阅读说明：本技术 电动式致动器和电动制动装置 (Electric actuator and electric brake device ) 是由 增田唯 于 2020-03-19 设计创作，主要内容包括：提供可靠地使逆输入保持机构动作,并且可谋求成本的降低的电动式致动器和电动制动装置。该电动式致动器的控制装置(2)包括：马达角度推定机构(22a)；逆输入保持控制部(24),该逆输入保持控制部(24)在电动式致动器(DA)发挥负荷的状态,通过螺线管(16)的控制,具有将卡合部(15)与被卡合部卡合且使驻车制动机构(7)处于逆输入保持状态的功能、以及从逆输入保持状态使卡合部(15)与上述被卡合部脱离且使驻车制动机构(7)处于逆输入保持解除状态的功能。逆输入保持控制部(24)具有卡合中间控制功能部(24a),该卡合中间控制功能部(24a)以针对在使卡合部(15)与被卡合部卡合时、以及卡合部(15)与被卡合部的脱离时,在一定时间内被卡合部和卡合部(15)处于已确定的位置关系的方式,控制所推定的旋转角度。(Provided are an electric actuator and an electric brake device which can reliably operate a reverse input holding mechanism and can reduce the cost. The control device (2) for the electric actuator comprises: a motor angle estimation mechanism (22 a); and a reverse input hold control unit (24) which, when the electric actuator (DA) is in a state of exerting a load, has a function of engaging the engaging unit (15) with the engaged unit and bringing the parking brake mechanism (7) into a reverse input hold state, and a function of disengaging the engaging unit (15) from the engaged unit from the reverse input hold state and bringing the parking brake mechanism (7) into a reverse input hold release state, under the control of the solenoid (16). The reverse input hold control unit (24) has an intermediate engagement control function unit (24a), and the intermediate engagement control function unit (24a) controls the estimated rotation angle so that the engaged portion and the engaging portion (15) are in a predetermined positional relationship for a certain period of time when the engaging portion (15) is engaged with the engaged portion and when the engaging portion (15) is disengaged from the engaged portion.)

1. An electric actuator, comprising: an electric motor having a stator and a rotor; a control device that controls the electric motor;

the electric actuator includes a reverse input holding mechanism having an engaged portion that moves in synchronization with the rotor and a click mechanism that has a drive source that drives the engaging portion so as to be able to engage with and disengage from the engaged portion, the reverse input holding mechanism holding a load generated by the electric actuator without depending on a torque of the electric motor so that the rotation of the electric motor is prevented by engaging the engaging portion with the engaged portion,

the control device includes:

a motor angle estimating unit that estimates a rotation angle of the electric motor;

a reverse input holding control unit having a function of engaging the engaging portion with the engaged portion and bringing the reverse input holding mechanism into a reverse input holding state and a function of disengaging the engaging portion from the engaged portion and bringing the reverse input holding mechanism into a reverse input holding released state, under control of the drive source, in a state where the electric actuator exerts a load,

the reverse input hold control unit includes:

an intermediate engagement control function unit for: the estimated rotation angle is controlled so that the engaged portion and the engaging portion are in a predetermined positional relationship for a predetermined period of time, either or both of when the engaging portion is engaged with the engaged portion and when the engaging portion is disengaged from the engaged portion.

2. The electric actuator according to claim 1, wherein the control device includes: a motor angle control unit that controls an estimated angle, which is the estimated rotation angle, so as to track a target motor angle; a load estimation function unit that estimates a load applied to the outside by the electric actuator; a load control function unit that controls an estimated load estimated by the load estimation function unit so as to track a target load;

when the reverse input holding mechanism is in the reverse input holding released state by the reverse input holding control unit, the load control function unit is executed at least until the determined load is generated by the electric actuator, and the motor angle control unit is switched to when the engagement intermediate control function unit is executed.

3. The electric actuator according to claim 2, wherein the reverse input holding control unit has a function of, when engaging the engaging portion with the "engaged portion at the time of transition from the reverse input holding released state to the reverse input holding state", gradually rotating the electric motor in the same direction as the reaction torque of the reverse input from a rotation angle of the electric motor when the electric actuator is in a state of exerting a predetermined load in accordance with a target load in the reverse input holding state,

the reverse input hold control unit performs the following operations based on the engagement drive time and the engaged portion clearance angle,

the driving time at the time of engagement is set based on the driving force of the driving source acting at the time of engagement in the engagement portion and the inertia of the engagement portion, and is a time from the start of the engagement operation with the engaged portion to the end of the operation;

an engaged portion clearance angle that is set based on a clearance between the engaged portion and the engaging portion when the engaging portion and the engaged portion are engaged, the electric motor being rotatable in a state where the reverse input holding mechanism is engaged;

the operation is to gradually rotate the electric motor in the same direction as the reaction torque generated by the reverse input by an angle displacement amount of the electric motor set so that an angle displacement of the electric motor during the engagement driving time is smaller than the engaged portion gap angle.

4. The electric actuator according to claim 2 or 3, wherein the reverse input holding control unit has a function of storing a rotation angle of the electric motor in the reverse input holding state, and when the reverse input holding state is released, the electric motor is rotated in a direction opposite to a reaction torque of the reverse input by a motor angle amount that is smaller than "an engaged portion gap angle at which the electric motor is rotatable in a state in which the reverse input holding mechanism is engaged" and is not zero, which is set based on shapes of the engaging portion and the engaged portion, from the stored rotation angle in the reverse input holding state;

in a "disengagement driving period from the start of disengagement of the engagement portion from the engaged portion to the end of the operation", which is set based on the driving force of the driving source acting when the engagement portion is disengaged and the inertia of the engagement portion, the electric motor is maintained in a state of being rotated in a direction opposite to the reaction torque of the reverse input by a motor angle amount that is smaller than the gap angle of the engaged portion and is not zero.

5. The electric actuator according to any one of claims 2 to 4,

the control device has a function of deriving a load control target motor angle, which is a motor angle that is a target of load control, from the target load based on a relationship between the estimated load and the estimated rotation angle;

under a determined estimated load, correcting either or both of a load control target motor angle and an estimated motor angle based on a load control target electric motor angle derived from the determined estimated load based on the relationship and a load error from the estimated electric motor angle actually under the determined estimated load, and performing tracking control of the motor angle based on the corrected result;

the operation of switching to the motor angle control unit when the intermediate engagement control function unit is executed is an operation of stopping the correction of the motor angle based on the load error.

6. The electric actuator according to claim 5, wherein the control device executes the electric motor angle control unit with an electric motor angle obtained from "the estimated electric motor angle immediately before switching to the electric motor angle control unit" and "the determined electric motor angle adjustment bias" as a target electric motor angle when the estimated motor angle is controlled by the engagement intermediate control function unit so that the engaged portion and the engagement portion are in a predetermined positional relationship for a certain period of time.

7. The electric actuator according to claim 1, wherein the reverse input holding mechanism is a movable portion in which the engaging portion of the click mechanism moves linearly with respect to the engaged portion, and the engaged portion is formed with a hole or a groove having a contact surface parallel to a linear movement direction of the engaging portion with respect to any rotational direction of the electric motor.

8. An electric brake apparatus, comprising: braking the rotor; a friction member that is in contact with the brake rotor to generate braking force; the electric actuator according to any one of claims 1 to 7, wherein a load is generated when the friction material is operated to come into contact with the brake rotor, and a braking force is controlled,

the reverse input holding mechanism is a parking brake mechanism that holds a contact load of the brake rotor and the friction material at a predetermined load without depending on a torque of the electric motor.

Technical Field

The present invention relates to an electric actuator and an electric brake device mounted on a vehicle or the like.

Background

The following techniques have been proposed as electric actuators.

1. An electric actuator with a parking brake function is provided with a click mechanism on the outer periphery of a ratchet (patent document 1).

2. An electric actuator using a planetary gear mechanism and an electric motor (patent document 2).

Documents of the prior art

Patent document

Patent document 1: JP 2006-183809

Patent document 2: JP 2006-194356 publication

Disclosure of Invention

Problems to be solved by the invention

For example, as in the parking brake mechanism in the electric brake device of patent documents 1 and 2, there is a case where an electric actuator capable of locking while maintaining a predetermined load state without depending on the electric power of the motor is required.

In this case, in the electric actuator having the reverse input holding mechanism formed by engaging the movable portion and the stationary portion as in patent document 1, when the state is shifted to the reverse input holding state and when the reverse input holding state is released, it is often required to reliably perform the state shift. For example, if the reverse input hold mechanism is applied to the parking brake function unit of the electric brake device using the electric actuator, if the switching to the parking brake state, which is the reverse input hold state, fails, a problem occurs in that the vehicle moves on an inclined road or the like contrary to the intention of the driver, and if the parking brake release fails, a problem occurs in that the vehicle cannot start.

For example, in the case of a ratchet wheel as disclosed in patent document 1, in which an inclined portion is provided on the side of the engagement portion opposite to the side receiving the reverse input and the engagement is released at the inclined portion, the size of the engagement portion is increased by providing the inclined portion, and there is a problem that the variation in the holding load is increased when the reverse input is held. Further, since the structure of the engaging portion is relatively complicated, the processing cost may be a problem. Further, when the engagement is released by the inclined portion or the like as described above, it is necessary to appropriately manage the friction coefficient, the contact angle, and the like of the inclined portion in order to reliably release the engagement, and there may be a problem that the quality control cost increases or the reliability of the reverse input holding operation decreases.

An object of the present invention is to provide an electric actuator and an electric brake device that can reliably operate a reverse input holding mechanism and can reduce costs.

Means for solving the problems

Hereinafter, the present invention will be described with reference to the reference numerals of the embodiments for the sake of easy understanding.

An electric actuator DA according to the present invention includes: an electric motor 4, the electric motor 4 having a stator and a rotor; a control device 2, the control device 2 controlling the electric motor 4;

the electric actuator includes a reverse input holding mechanism 7, the reverse input holding mechanism 7 having an engaged portion Hk that moves in synchronization with the rotor and an engagement mechanism Ks having a drive source 16, the drive source 16 driving an engagement portion 15 so as to be engageable with and disengageable from the engaged portion Hk, the reverse input holding mechanism 7 holding a load generated by the electric actuator DA without depending on a torque of the electric motor 4 so that rotation of the electric motor 4 is prevented by engagement of the engagement portion 15 with the engaged portion Hk;

the control device 2 includes:

a motor angle estimating means 22a for estimating a rotation angle of the electric motor 4 by the motor angle estimating means 22 a;

a reverse input holding control unit 24 that, when the electric actuator DA is in a loaded state, has a function of engaging the engaging portion 15 with the engaged portion Hk and bringing the reverse input holding mechanism 7 into a reverse input holding state, and a function of disengaging the engaging portion 15 from the engaged portion Hk from the reverse input holding state and bringing the reverse input holding mechanism 24 into a reverse input holding released state, under the control of the drive source 16;

the reverse input hold control unit 24 includes:

an intermediate engagement control function unit 24a, the intermediate engagement control function unit 24a being directed to: the estimated rotation angle is controlled so that the engaged portion Hk and the engaging portion 15 are in a predetermined positional relationship for a predetermined period of time when either or both of the engaging portion 15 and the engaged portion Hk are engaged and the engaging portion 15 and the engaged portion Hk are disengaged.

The above-mentioned determined positional relationship is a positional relationship arbitrarily determined by design or the like, and is determined by finding an appropriate relationship by means of either or both of experiments and simulations, for example.

According to this configuration, the intermediate engagement control function unit 24a continuously maintains the positional relationship in which the engaged portion Hk and the engaging portion 15 are not in contact with each other, that is, the rotational angle of the electric motor 4 in accordance with the operation of the engaging portion 15, for a certain time required for the operation of the engaging portion 15 when the engaging portion 15 is engaged with or disengaged from the engaged portion Hk that moves in synchronization with the rotor of the electric motor 4, and maintains the engaging portion 15 in the intermediate engagement state with respect to the engaged portion Hk. Accordingly, the engaging portion 15 can be reliably engaged with or disengaged from the engaged portion Hk by the subsequent rotation of the electric motor 4, and the reverse input holding state or the reverse input holding release state can be more reliably shifted. Since the reverse input holding mechanism 7 can be reliably operated by such control, it is possible to reduce the cost as compared with the above-described conventional technique having a complicated structure or the like.

The control device 2 may be configured to include: a motor angle control unit 23b that controls an estimated angle that is an estimated rotation angle so as to track a target motor angle; a load estimation function unit 21 for estimating a load applied to the outside by the electric actuator DA; a load control function unit 23a that controls the estimated load estimated by the load estimation function unit 21 so as to track the target load;

when the reverse input holding mechanism 7 is placed in the reverse input holding released state by the reverse input holding control unit 24, the load control function unit 23a is executed at least until the specified load is generated by the electric actuator DA, and the engagement intermediate control function unit 24a is switched to the motor angle control unit 23 b.

The determined load is a load arbitrarily determined by design or the like, and is determined by finding an appropriate relationship by one or both of a test and a simulation, for example.

In general, angle estimation using an angle sensor or the like is often able to achieve a high control resolution for a motor angle, as compared with load estimation using a load sensor, a flow sensor, or the like. Therefore, in this embodiment, when the reverse input holding mechanism 7 is placed in the reverse input holding released state, the load control function unit 23a is executed until the specified load is generated in the electric actuator DA, and the motor angle control unit 23b is switched to when the engagement intermediate control function unit 24a is executed, whereby the positional relationship between the engagement unit 15 and the engaged unit Hk can be controlled more accurately. Therefore, the transition to the reverse input holding state or the release of the reverse input holding state can be performed more accurately.

The reverse input holding control unit 24 may be configured to, when the engaging portion 15 is engaged with the engaged portion Hk at the time of the transition from the reverse input holding released state to the reverse input holding state, gradually rotate the electric motor 4 in the same direction as the reaction torque of the reverse input from the rotation angle of the electric motor 4 when the electric actuator DA is in a state of exerting a predetermined load in accordance with the target load in the reverse input holding state;

the reverse input hold control section 24 performs the following operations based on the engagement drive time and the engaged portion clearance angle,

the engagement driving time is set based on the driving force of the driving source 16 acting at the time of engagement with the engagement portion 15 and the inertia of the engagement portion 15, and is a time from the start of the engagement operation with the engaged portion Hk of the engagement portion 15 to the end of the operation;

an engaged portion clearance angle which is set based on a clearance between the engaged portion Hk and the engaging portion 15 when the engaging portion 15 is engaged with the engaged portion Hk, and in which the electric motor 4 is rotatable in a state where the reverse input holding mechanism 7 is engaged;

the operation is to gradually rotate the electric motor 4 in the same direction as the reaction torque generated by the reverse input, by the angle displacement amount of the electric motor 4 set so that the angle displacement of the electric motor 4 in the driving time at the time of engagement is smaller than the engaged portion gap angle.

The determined load is a load arbitrarily determined by design or the like, and is determined by finding an appropriate relationship by one or both of a test and a simulation, for example.

According to this configuration, when the absolute position of the engaged portion Hk with respect to the motor angle is unclear, the electric motor 4 is gradually rotated in the same direction as the reaction torque generated by the reverse input by the angular displacement amount of the electric motor 4 set so that the angular displacement of the electric motor 4 during the driving time at the time of engagement is smaller than the engaged portion clearance angle, whereby the engagement portion 15 can be reliably engaged with the engaged portion Hk.

The reverse input holding control unit 24 may be configured to have a function of storing the rotation angle of the electric motor 4 in the reverse input holding state, and to rotate the electric motor 4 in a direction opposite to the reaction torque of the reverse input by a motor angle amount that is smaller than the "engaged portion clearance angle at which the electric motor 4 can rotate in the engaged state of the reverse input holding mechanism 7" and is not zero, which is set based on the shapes of the engaging portion 15 and the engaged portion Hk, from the stored rotation angle in the reverse input holding state when the reverse input holding state is released;

in a "disengagement driving period from the start of disengagement of the engagement portion 15 from the engaged portion Hk to the end of the operation", which is set based on the driving force of the driving source 16 acting when the engagement portion 15 is disengaged and the inertia of the engagement portion 15, the electric motor 4 is maintained in a state of being rotated in a direction opposite to the reaction torque of the reverse input by a motor angle amount smaller than the engaged portion clearance angle and not zero.

According to this configuration, since the absolute position of the motor angle with respect to the engaged portion Hk is known in advance when the reverse input holding state is released, the state in which the gap is generated between the engaged portion Hk and the engaging portion 15 is maintained during the drive at the time of disengagement of the latch mechanism Ks, and thus the reverse input holding state can be reliably released.

The control device 2 may be configured to have a function in which the load control function unit 23a derives a load control target motor angle, which is a motor angle to be a load control target, from the target load based on a relationship between the estimated load and the estimated rotation angle;

under a determined estimated load, correcting either or both of a load control target motor angle and an estimated motor angle based on a load control target motor angle derived from the determined estimated load based on the relationship and a load error from the estimated motor angle that is actual under the determined estimated load, and performing tracking control of the motor angle based on the corrected result;

the operation of switching to the motor angle control unit 23 when the intermediate engagement control function unit 24a is executed is an operation of stopping the correction of the motor angle based on the load error.

The estimated load determined as described above is a load arbitrarily determined by design or the like, and is determined by, for example, obtaining an appropriate load by one or both of experiments and simulations. In this case, the control of the load of the electric actuator DA is substantially configured as the motor angle control, and the control switching is performed by on-off correction of the motor angle, whereby smooth control switching can be performed.

The control device 2 may be configured to execute the motor angle control unit 23b with a motor angle obtained from the "estimated motor angle immediately before switching to the motor angle control unit 23 b" and the "determined motor angle adjusting bias" as a target motor angle when the estimated motor angle is controlled by the engagement intermediate control function unit 24a so that the engaged portion Hk and the engaging portion 15 are in a predetermined positional relationship for a predetermined time. In this manner, the motor angle control unit 23b is operated.

The reverse input holding mechanism 7 may be a movable portion in which the engaging portion 15 of the click mechanism Ks linearly moves with respect to the engaged portion Hk, and the engaged portion Hk may be formed with a hole ha or a groove mz having a contact surface parallel to the linear movement direction of the engaging portion 15 in any rotational direction of the electric motor 4. In this case, by forming simple holes ha and grooves mz in the engaged portion Hk, the pitch between adjacent holes or grooves in the circumferential direction of the engaged portion Hk can be made small. Therefore, the reverse input holding load can be finely adjusted, and the processing cost can be reduced.

The electric brake device 1 of the present invention relates to an electric brake device including: a brake rotor 8; a friction member 9 that generates braking force by coming into contact with the brake rotor 8; an electric actuator DA of any one of the above configurations of the present invention that generates a load when the friction material 9 is operated to come into contact with the brake rotor 8 and controls a braking force;

the reverse input holding mechanism 7 is a parking brake mechanism that holds a contact load of the brake rotor 8 and the friction material 9 at a predetermined load without depending on the torque of the electric motor 4.

The determined load is a load that is arbitrarily determined by design or the like, and is determined by, for example, obtaining an appropriate load by one or both of a test and a simulation. According to this configuration, the effects described above with respect to the electric actuator DA of the present invention are obtained. Further, since the parking brake mechanism can be reliably operated, it is possible to reliably prevent the vehicle from undesirably moving backward on an inclined road or the like.

Any combination of at least two of the aspects disclosed in the claims and/or the description and/or the drawings is comprised in the present invention. In particular, any combination of two or more of the claims is also encompassed by the present invention.

Drawings

The present invention can be more clearly understood by the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and the drawings are only for illustration and description and are not intended to limit the scope of the present invention. The scope of the invention is determined by the claims. In the drawings, like numbering represents like parts throughout the several views.

Fig. 1 is a schematic view of an electric brake device according to embodiment 1 of the present invention;

fig. 2 is a diagram showing a configuration example of a reverse input holding mechanism of the electric brake device;

fig. 3 is a diagram schematically showing a state in which the engaging portion is engaged with and disengaged from the engaged portion in the reverse input holding mechanism.

Fig. 4 is a block diagram of a control system of an electric actuator of the electric brake apparatus;

fig. 5 is a flowchart showing an example of the operation of the parking brake mechanism of the electric brake device;

FIG. 6 is a flowchart showing an example of the operation of releasing the parking brake mechanism;

fig. 7 is a block diagram showing an example of the operation of the control device of the electric brake device;

fig. 8 is a block diagram showing an example of the operation of the control device of the electric brake device;

fig. 9 is a block diagram showing an example of the operation of the control device of the electric brake device;

fig. 10 is a block diagram showing an example of the operation of the control device of the electric brake device;

fig. 11 is a block diagram showing an example of the operation of the control device of the electric brake device;

fig. 12 is a block diagram showing an example of the operation of the control device of the electric brake device;

fig. 13 is a diagram showing an example of operation of the parking brake mechanism;

fig. 14 is a diagram showing another operation example of the parking brake mechanism;

fig. 15A is a diagram showing a configuration example of an inverse input holding mechanism of an electric actuator according to another embodiment of the present invention;

fig. 15B is a diagram showing a configuration example of an inverse input holding mechanism of an electric actuator according to another embodiment of the present invention;

fig. 16A is a diagram showing a configuration example of an inverse input holding mechanism of an electric actuator according to still another embodiment of the present invention;

fig. 16B is a diagram showing a configuration example of an inverse input holding mechanism of an electric actuator according to still another embodiment of the present invention;

fig. 16C is a diagram showing a configuration example of an inverse input holding mechanism of an electric actuator according to another embodiment of the present invention;

fig. 17 is a block diagram of a control system of an electric actuator according to another embodiment of the present invention.

Detailed Description

[ embodiment 1 ]

An electric brake device having an electric actuator according to an embodiment of the present invention will be described with reference to fig. 1 to 14. The electric brake device is mounted on a vehicle, for example. As shown in fig. 1, the electric brake device 1 includes an electric actuator DA and a friction brake BR. First, the structures of the electric actuator DA and the friction brake BR will be described.

< Structure of electric actuator DA and Friction brake BR >

The electric actuator DA includes an actuator body AH, a power supply device 3, and a control device 2 described later. The actuator body AH includes an electric motor 4, a linear movement mechanism 6, a speed reducer 5, a parking brake mechanism 7, an angle sensor Sa (fig. 4), and a load sensor Sb (fig. 4). As shown in fig. 4, the brake actuator BA is constituted by an actuator body AH and a friction brake BR.

As shown in fig. 1 and 4, the electric motor 4 has a rotor and a stator, and is constituted by a permanent magnet type synchronous motor, for example. This embodiment is preferable because the electric motor 4 can be a permanent magnet type synchronous electric motor because it can save space, has high efficiency, and has high torque. The friction brakes BR are respectively provided on the wheels of the vehicle. The friction brake BR includes a brake rotor 8 that rotates in conjunction with a wheel, and a friction material 9 that comes into contact with the brake rotor 8 to generate a braking force. The friction member 9 is operated by an electric actuator DA. A mechanism may be used in which the friction member 9 is pressed against the brake rotor 8 by operating the actuator body AH of the electric actuator DA, and a load is generated by a frictional force. The friction brake BR of this example is a disc brake device using a brake rotor 8 as a brake disc and a caliper not shown in the figure, but may be a drum brake device using a drum and a lining.

The speed reducer 5 is a mechanism for reducing the rotation of the electric motor 4, and includes a primary gear 12, an intermediate (secondary) gear 13, and a tertiary gear 11 as transmission portions, respectively. In this example, the reduction gear 5 is a parallel gear capable of reducing the rotation of the primary gear 12 attached to the rotor shaft 4a of the electric motor 4 by the intermediate gear 13 and transmitting the reduced rotation to the tertiary gear 11 fixed to the end of the rotary shaft 10.

The linear movement mechanism 6 is a mechanism that converts the rotational motion output from the speed reducer 5 into a linear motion of the linear movement unit 14 by a feed screw mechanism, and causes the friction material 9 to abut against or separate from the brake rotor 8. The linearly moving portion 14 is supported to be movable in the axial direction indicated by an arrow a1 (fig. 1) while being prevented from rotating. A friction member 9 is provided at the outer end of the linearly moving portion 14. The rotation of the electric motor 4 is transmitted to the linear movement mechanism 6 via the speed reducer 5, and the rotational motion is converted into the linear motion, which is converted into the pressing force of the friction material 9, thereby generating the braking force. In a state where the electric brake device 1 is mounted on a vehicle, the vehicle width direction outer side of the vehicle is referred to as an outer side, and the vehicle width direction center side of the vehicle is referred to as an inner side.

As shown in fig. 4, the angle sensor Sa detects the rotation angle (motor angle) of the electric motor 4. The angle sensor Sa is preferably of this type because it has high accuracy and high reliability when a resolver, a magnetic encoder, or the like is used, for example, but various sensors such as an optical encoder may be used. Instead of using the angle sensor Sa, the control device 2 described later may use a non-angle sensor estimation for estimating the motor angle from the relationship between the voltage and the current of the electric motor 4.

The load sensor Sb detects the axial load of the linear movement mechanism 6. This load sensor Sb is preferably used in a low-cost and high-precision manner by using a sensor for detecting strain, deformation, or the like corresponding to the load of the linear movement mechanism 6, for example. The load sensor Sb may be a pressure-sensitive medium such as a piezoelectric element, a torque sensor for detecting a braking torque of the brake rotor 8, an acceleration sensor for detecting a front-rear deceleration of the vehicle in the case of the electric brake device 1 for a vehicle, or the like. Alternatively, the control device 2 may perform sensorless estimation without providing a load sensor based on predetermined correlations such as the correlation between the actuator rigidity and the motor angle and the correlation between the actuator load and the motor torque.

< example of Structure of reverse input holding mechanism (parking brake mechanism) >

As shown in fig. 1 and 2, the parking brake mechanism 7 is a reverse input holding mechanism that holds a load (brake load) generated by the electric actuator DA regardless of the torque of the electric motor 4. The parking brake mechanism 7 includes: an engaged portion Hk having a plurality of holes ha formed therein; the latch mechanism Ks includes a solenoid 16, and the solenoid 16 is a driving source for driving the engaging portion 15 to be engageable with and disengageable from each hole ha of the engaged portion Hk.

The engaged portion Hk is an intermediate gear 13 of the reduction gear 5 in this example, and a plurality of holes ha are provided at equal intervals on the circumference of the end face of the intermediate gear 13 in the rotation axis direction. As shown in fig. 2 and 3, the engaged portion Hk forms a hole ha having a contact surface parallel to the linear movement direction of the engaging portion 15 in any rotational direction of the electric motor 4 (fig. 1). In this structure, when the reverse input is held, the engaging portion 15 protrudes from the solenoid 16 held in a stationary system such as a housing and opposed thereto, and engages with any one of the holes ha to block the rotation of the electric motor 4 (fig. 1), and the engaged state is held by the frictional force of the contact surface, so that the reverse input is held without being affected by the torque of the electric motor 4 (fig. 1). Although fig. 2 shows an example of a through hole that penetrates in the axial direction as each hole ha, the hole ha may be a non-through hole that does not penetrate but has a predetermined depth. The shape of the hole ha is not limited to a circular hole, and may be a long hole, a slit hole, a polygonal hole, or the like. Instead of the hole ha, a shape in which a concave-convex portion is formed in the circumferential direction on the end surface in the rotation axis direction may be used.

The solenoid 16 generates an excitation magnetic field by a solenoid coil, drives the engagement portion 15 as a movable portion by an electromagnetic force, and locks the rotation of the intermediate gear 13 as a movable portion that is interlocked with the electric motor 4 (fig. 1) by engaging the engagement portion 15 as a latch pin with the engaged portion Hk provided in the reducer 5 (fig. 1) facing each other, thereby bringing the parking lock state (reverse input holding state). The engagement portion 15 is disengaged from the engaged portion Hk, so that the rotation of the intermediate gear 13 is permitted and the state is unlocked (reverse input holding release state).

In this embodiment, if a biasing mechanism (not shown in the drawings) such as a spring for holding the engaging portion 15 in a state of being separated from the engaged portion Hk is provided in the solenoid 16, and an electromagnetic force exceeding the urging force of the biasing mechanism is generated by energization regardless of the polarity to be in a lockable state, electric power can be saved at low cost, which is preferable. However, the solenoid 16 may be configured, for example, in such a manner that: an excitation portion such as a magnet is provided to the engagement portion 15 as the catch pin, and the engagement portion 15 is driven in both directions in accordance with the direction of the current of the solenoid coil.

The drive source may be a DC motor and a screw mechanism instead of the solenoid 16 to lock the engaged portion Hk. The engaged portion Hk is preferably provided in the reduction gear to save space, but may be provided at any position such as a rotor of the electric motor 4 (fig. 1) or the linear movement mechanism 6 (fig. 1) that operates in conjunction with the rotation of the motor. As elements not shown in the figure, various sensors such as a thermistor may be additionally provided according to requirements.

< construction of control device >

Fig. 4 is a block diagram of a control system of the electric actuator DA of the electric brake device 1. For example, the control device 2 and the brake actuator BA are provided corresponding to each wheel. Each control device 2 controls the corresponding electric motor 4. The dc power supply device 3 and the upper ECU 17 as upper control means of each control device 2 are connected to each control device 2. The power supply device 3 supplies electric power to the electric motor 4 and the control device 2. The power supply device 3 can use, for example, a low-voltage (e.g., 12V) battery or a step-down converter that steps down a high-voltage battery in the electric brake device 1 for an automobile. Alternatively, the power supply device 3 may use a high-capacity capacitor or the like, or may use them in parallel for redundancy.

As the upper ECU 17, for example, a Vehicle integrated Control Unit (VCU) that controls the entire Vehicle can be applied. The upper ECU 17 has a comprehensive control function of each control device 2. The upper ECU 17 has a brake command mechanism 17a and a parking brake command mechanism 17 b. The brake command mechanism 17a supplies, in an automobile, an output of a sensor that changes in accordance with an operation amount of a brake operating mechanism such as a brake pedal to each control device 2 as a brake command signal.

The brake command mechanism 17a may be, for example, a brake operating mechanism itself such as a brake pedal, or may automatically obtain and output a command value (brake command signal) according to a state of the vehicle and information of various sensors, etc., without depending on an operation of the brake operating mechanism, such as an autonomous vehicle. The parking brake command means 17b is a parking brake switch or the like, and supplies a parking brake command signal to the control device 2 in accordance with an operation by an operator, a state of a vehicle such as an autonomous vehicle, and information from various sensors or the like.

Each control device 2 includes various control operators that perform control calculations, a motor driver 18, a solenoid driver 19, and a current sensor 20. The various control arithmetic units described above include a load estimation function unit 21, a motion state estimator 22, an actuator controller 23, and a reverse input hold control unit 24. The load estimation function unit 21 estimates a braking load, which is a load applied to the outside by the electric actuator DA, based on the output of the load sensor Sb. As described above, the load estimation function unit 21 may perform sensorless estimation without using the load sensor Sb.

The motion state estimator 22 estimates the rotational motion state of the electric motor 4 based on the output of the angle sensor Sa. The motion state estimator 22 includes a motor angle estimating mechanism 22a that estimates the angle (rotation angle) of the rotor of the electric motor 4, and an angular velocity estimating unit 22b that estimates the angular velocity of the electric motor 4. Alternatively, the motion state estimator 22 may be provided with a function of estimating a predetermined micro-integration value such as an angular acceleration of the electric motor 4, a function of estimating disturbance, and the like, for example.

The motor angle estimating unit 22a has a function of appropriately obtaining a necessary physical quantity from a control configuration such as an electrical angle phase for current control, or a total rotation angle for correcting overlap or lack of overlap of the angle sensor Sa for angle control, when estimating the rotation angle of the electric motor 4. The rotation angle and the angular velocity may be, for example, angles of predetermined portions of the reduction gear unit 5 obtained from a reduction gear ratio, or positions and velocities obtained from an equivalent lead or the like, instead of the rotor of the electric motor 4. The estimation of the physical quantity may be performed by using a structure such as a state estimation observer, or may be performed by a direct operation such as differentiation or an inverse operation based on an inertial equation.

The current sensor 20 may be, for example, a sensor including an amplifier that detects a voltage across a shunt resistor, or a non-contact sensor that detects a magnetic flux or the like around a current path of a phase current of the electric motor 4. Other configurations of the current sensor 20 may be configured to detect a terminal voltage of an element or the like constituting the motor driver 18, for example. In addition, the current sensor 20 may be provided between the electric motor phases, or one or more current sensors may be provided on the low side or the high side. Alternatively, the control device 2 may perform feed-forward control based on motor characteristics such as inductance and resistance of the electric motor 4 without providing any current sensor.

The actuator controller 23 has a function of obtaining an operation amount for ideally causing the brake actuator BA to follow a predetermined command input, and converting the operation amount into a motor drive signal. The actuator controller 23 includes a brake load control unit 23a and a motor angle control unit 23b as load (brake load) control function units, and switches the brake load control unit 23a and the motor angle control unit 23b according to conditions. The brake load control unit 23a is a control unit mainly for controlling a brake load (braking force). The motor angle control unit 23b controls the estimated motor angle, which is the estimated rotation angle, so as to track the target motor angle. Further, as functions not shown in the drawings, it is preferable that the actuator controller 23 is provided with a current controller for controlling the motor current and a function of deriving the motor current for generating a desired motor torque based on the motor output characteristic, so that high-function control can be performed.

The reverse input hold control unit 24 has a function of bringing the parking brake mechanism 7 as the reverse input hold mechanism into a reverse input hold release state, a solenoid engagement angle control state, a reverse input hold state, and a solenoid disengagement angle control state, which will be described later, respectively. The reverse input hold control unit 24 has a control calculation function of engaging the engaging portion 15 with the engaged portion Hk by the control of the solenoid 16 in a state where the electric actuator DA exerts a load, that is, in a state where a predetermined braking load is exerted, and holding the braking load without driving the electric motor 4 to operate the electric motor 4 and the solenoid 16 in cooperation.

Specifically, the reverse input holding control unit 24 includes an intermediate engagement control function unit 24a that controls the estimated motor angle so that the engaged portion Hk and the engaging portion 15 are in a predetermined positional relationship for a predetermined time period in both cases when the engaging portion 15 is engaged with the engaged portion Hk and when the engaging portion 15 is disengaged from the engaged portion Hk. The engagement intermediate control function unit 24a has a function of setting the reverse input holding mechanism to the solenoid engagement angle control state and the solenoid disengagement angle control state described above.

The reverse input hold release state is a state in which the engagement portion 15 is released from the engaged portion Hk, and is a state in which a normal auxiliary brake is applied. At this time, the control switching signal is in a state of executing the brake load control by the brake load control unit 23a, and the brake actuator BA operates in accordance with the brake command input (brake command signal).

The electromagnetic engagement angle control state is a state in which the motor angle is controlled in order to engage the engaged portion Hk with the engagement portion 15 of the solenoid 16. At this time, the control switching signal is in a state where the motor angle control unit 23b performs the motor angle control, and for example, the engaged portion Hk can be locked by energizing the solenoid 16 while the position of the engaged portion Hk and the position of the engaging portion 15 of the solenoid 16 are maintained in an engageable positional relationship.

The reverse input holding state is a locked state in which the engaged portion Hk is locked by the engaging portion 15 of the electromagnetic element 16, and the locked state is held without consuming the motor power by a frictional force generated by the reverse input acting on the contact surface of the engaged portion Hk with respect to the engaging portion 15. At this time, the electric motor 4 may be in a failure state in which the energization is stopped, or may be in a state in which the control is continuously executed in a power saving manner such as zero torque, or may be a combination thereof. The reverse input hold control unit 24 outputs a control switching signal to the actuator controller 23 according to which state the electric motor 4 is in during reverse input hold.

The solenoid separation angle control state is a state in which the motor angle is controlled in order to separate the engaging portion 15 of the solenoid 16 from the engaged portion Hk. At this time, the control switching signal is in a state where the motor angle control is executed by the motor angle control unit 23b, and for example, in the case of the solenoid 16 having a biasing mechanism such as a release spring, the engaged portion Hk is driven to the brake pressure increasing side, which is the side opposite to the reverse input side, to such an extent that the above-described frictional force does not act, and the lock of the engaged portion Hk is released by the spring force of the release spring. When a solenoid 16 having a bias spring or the like is replaced with a bi-directional driving solenoid, a DC motor or the like, the solenoid or the DC motor is driven to the disengagement side of the engagement portion 15 in a state where the frictional force is not exerted, and the lock of the engaged portion Hk is released.

The motor driver 18 controls the electric power supplied to the electric motor 4. The motor driver 18 is inexpensive and high in performance by configuring a half-bridge circuit using switching elements such as Field Effect Transistors (FETs), for example, and by configuring the half-bridge circuit to perform PWM control for determining a motor applied voltage based ON the ON-OFF duty ratio of the switching elements. Alternatively, PAM control may be performed by providing a transformer circuit or the like.

The solenoid driver 19 drives and controls the solenoid 16 in accordance with a solenoid ON/OFF signal supplied from the reverse input holding control unit 24. For example, the solenoid driver 19 is preferably constituted by a switching element such as a field effect transistor or a bipolar transistor because of its low cost. In the case of the solenoid 16 having the biasing spring, one switch element may be provided as a switch for connecting/disconnecting the current from the power supply device 3 to the solenoid 16, or a switch for connecting/disconnecting the current from the solenoid 16 to GND, or both of them may be provided to make the configuration redundant. In the case of a bi-directionally driven solenoid, a DC motor, or the like, a bridge circuit having 4 switching elements can be configured at minimum.

As elements other than those shown in the drawing, it is preferable to supply the electric power from the power supply device 3 directly to the motor driver 18 or the solenoid driver 19, and among the various control arithmetic units described above, a small-sized step-down converter may be used in the control device 2, or electric power may be supplied to either or both of the motor driver 18 and the solenoid driver 19 via a step-up converter.

Fig. 4 shows an example of the electric brake device 1 having the parking brake mechanism 7 for a vehicle, but the applicable vehicle may be an automobile or a railway vehicle. The present invention can also be applied to an electric actuator DA for other applications having a reverse input holding mechanism. For example, the present invention can be applied to a rotation stop brake of a wind turbine, a water turbine, or the like having a pinch holding function at power saving, or can be applied to an electric pressure device having a pressure holding function, or the like. As another example of these applications, the peripheral structures of the control device 2 such as the brake command mechanism 17a and the parking brake command mechanism 17b may be configured as appropriate for each application.

< example of operation flow for holding inverse input >

Fig. 5 is a flowchart showing an example of the operation of the parking brake mechanism of the electric brake device shown in fig. 4. As shown in fig. 4 and 5, this operation flow is an internal flow of the reverse input holding control unit 24 and the actuator controller 23. The basic operation flow is also the same in the electric valve device (fig. 17) described later and other applications.

The lock start condition of the parking brake mechanism PBK may be, for example, a state in which the parking brake switch is operated by the operator and the parking brake mechanism is turned on. Alternatively, for example, in the case where the parking brake mechanism is automatically operated during a relatively long-time parking, the signal may be a signal independent of the operation of the operator, such as when the vehicle is parked in another autonomous vehicle.

After the PBK lock is started, if the brake load control is not in progress (NO in step S1), the control is switched to the brake load control by the control switching signal (step S2), and the process proceeds to step S3. The case where the braking load control is not being executed is, for example, a case where a predetermined gap is provided between the friction material 9 and the brake rotor 8 during brake release to perform gap control (motor angle control or the like). If the brake load control is in progress (YES at step S1), the process proceeds to step S3.

In step S3, the brake load control unit 23a performs brake load control to pressurize the brake until the brake reaches a predetermined load, i.e., a parking brake load. Here, the target brake load (target load) set as the parking brake load may be a predetermined brake load in which the influence of the pitch between the holes ha and ha adjacent in the circumferential direction of the engaged portion Hk when the reverse input holding mechanism is applied (fig. 3), the reduction ratio, and the amount of brake load variation depending on the unit pitch such as the screw lead is added to the predetermined parking brake load.

After the predetermined parking brake load is reached, the brake load control is switched to the motor angle control by the motor angle control unit 23b in accordance with the control switching signal (step S4). After that, the solenoid is operated (step S5). The state of solenoid operation is an operation of energizing the solenoid coil in the solenoid 16 in which the engaging portion 15 is projected by the attraction force of the solenoid coil and the engaging portion 15 is separated by the spring reaction force, for example, an operation of energizing the solenoid coil in the direction in which the catch mechanism is projected in a solenoid, a DC motor, or the like that is driven bidirectionally in the direction of current flow. Steps S4 and S5 may be reversed, or the solenoid may be operated and then switched to the motor angle control, or these operations may be performed simultaneously.

The engagement intermediate control function unit 24a keeps the motor angle for a predetermined time (fixed time) before the solenoid 16 completes the projection operation, in other words, to secure the projection time of the solenoid 16 (step S6). The predetermined time may be determined, for example, based on a solenoid projection time derived from a stroke amount of projection from the solenoid, a weight of the engaging portion 15 as the movable portion, a solenoid driving force, and the like, and is preferably set in consideration of an influence of a slip resistance, a temperature change, a variation in driving force due to an individual difference, and the like. Note that this operation may be implemented as angular velocity control for making the target angular velocity zero, for example.

Next, the electric motor 4 is rotated by a predetermined amount in the pressure reducing direction (see fig. 3), and the engaging portion of the solenoid is engaged with the engaged portion (step S7). At this time, for example, when the gear of the reduction gear 5 is applied as the engaged portion Hk, since the relative positional relationship of the engaged portion Hk with respect to the motor angle is not known in many cases, in order to project the solenoid 16 and engage with the engaged portion Hk, it is necessary to make the motor angle transition in the pressure reducing direction sufficiently gentle.

Specifically, first, when the solenoid 16 protrudes in a positional relationship in which the engaged portion Hk and the engaging portion 15 of the solenoid 16 do not match (for example, a state in which the holes of the solenoid valve and the engaged portion Hk are not substantially coaxial), the tip end of the engaging portion 15 comes into surface contact with the shaft end of the engaged portion Hk and stops in a halfway stroke state. Then, while the electric motor 4 and the engaged portion Hk are rotating in the pressure reducing direction, the engaging portion 15 of the solenoid 16 protrudes from the stroke halfway state to the full stroke state in a state where the relative positions of the engaged portion Hk and the engaging portion 15 of the solenoid 16 are matched.

Therefore, for example, when the angular velocity of the motor is too large with respect to the time during which the engaging portion 15 protrudes from the halfway stroke state to the full stroke state, there is a possibility that the solenoid in the halfway state may be locked or the locking may fail. Therefore, the motor angular velocity ω sn needs to be at least | ω sn | < | θ lk/tsn |, in a relationship including an angle θ lk, which is an angle at which the electric motor 4 and the engaged portion Hk can rotate due to a gap between the engaged portion Hk and the engaging portion 15 or the like in a state where the engaging portion 15 of the solenoid 16 is engaged (a state where the engaging portion 15 of the solenoid 16 is inserted into a hole of the gear), and a time tsn, which is a time during which the engaging portion 15 protrudes from the middle of the stroke to the full stroke.

Further, the motor angular velocity ω sn is preferably set under conditions of angular velocity that take into account the influences of sliding resistance, variations in driving force due to temperature changes and individual differences, a predetermined safety factor based on design requirements, and the like. This operation may be angle control in which the motor angle command value changes at a constant slope, or may be realized by angular velocity control of the motor angular velocity command as a whole.

In the case where the positional relationship of the engaged portion Hk can be grasped in advance such as when the engaged portion Hk is provided on the motor shaft, the motor angle may be stopped in advance at a position where the positional relationship between the engaged portion Hk and the engaging portion 15 of the solenoid 16 can be engaged, and the engaging portion 15 of the solenoid 16 may be protruded. In addition, in the motor rotation operation at the time of engagement, the limitation of the motor angular velocity as described above is not taken into consideration, and the engaging portion 15 only needs to be able to reliably contact the contact surface of the hole of the engaged portion Hk.

Subsequently, whether or not the lock state is established is checked (step S8), and if the lock state is established (step S8: YES), the energization of the electric motor 4 and the solenoid 16 is stopped (step S9). For example, when the motor angle is maintained for a certain time even when the electric motor 4 rotates, it is determined that the lock state is established. If the state is not the locked state (NO in step S8), the rotation state of the electric motor 4 after the decompression is started in step S7 is confirmed (step S10), and when the rotation amount of the electric motor 4 is small (NO in step S10), the process returns to step S7, and the electric motor 4 is rotated in the decompression direction. When the rotation amount of the electric motor 4 is large (yes in step S10), the present process is ended as a lock operation failure. The amount of rotation is preferably set based on the amount of pitch between holes ha, ha (fig. 3) adjacent in the circumferential direction of the engaged portion Hk, for example.

In addition, although step S9 shows an example in which the energization of the electric motor 4 and the solenoid 16 is stopped after the lock, this operation can be set as appropriate depending on the system design requirements. For example, in order to shorten the start-up time of the control device 2, the electric motor 4 may be put on standby in a power-saving driving state such as zero torque or zero current, or these processes may be performed simultaneously.

Fig. 6 shows an example of releasing the parking brake mechanism from the reverse input hold state during the execution of the parking brake of fig. 5. The control bodies of fig. 6 are also the reverse input holding control unit 24 (fig. 4) and the actuator controller 23 (fig. 4). As shown in fig. 4 and 6, the release start condition of the parking brake mechanism PBK is, for example, a state in which the parking brake mechanism is turned off when the parking brake switch is operated by the operator.

As shown in fig. 6 and 4, when the release start condition of the parking brake mechanism PBK is satisfied, the control is switched to the motor angle control by the motor angle control unit 23b by the control switching signal (step S11), the electric motor 4 is rotated in the direction opposite to the reaction torque by the reverse input, that is, in the pressure-increasing direction (step S12), and the state in which the electric motor 4 is rotated in the pressure-increasing direction for a predetermined time (during the disengagement drive time) is maintained (step S13). The state before switching to the motor angle control (step S11) may be arbitrarily determined according to the operation in the reverse input holding state, other design requirements, and the like.

The reverse input holding control unit 24 has a function of storing the rotation angle of the electric motor 4 in the reverse input holding state, and when the reverse input holding state is released, rotates the electric motor 4 in the direction opposite to the reaction torque caused by the reverse input from the stored rotation angle in the reverse input holding state by "an amount of a motor angle that is smaller than the engaged portion gap angle set based on the shapes of the engaging portion 15 and the engaged portion Hk and is not zero and that the electric motor 4 can rotate in the state where the reverse input holding mechanism is engaged". Further, the reverse input holding control unit 24 maintains the following state during the disengagement drive time from the start of the drive of the click mechanism to the end of the operation of the engagement portion 15, which is set based on the driving force and inertia at the time of disengagement of the engagement portion 15: the electric motor 4 is rotated by a motor angle smaller than the engaged portion clearance angle and not equal to zero in a direction opposite to the reaction torque by the reverse input.

Specifically, in step S12, the electric motor 4 is rotated by a predetermined amount in the supercharging direction. The predetermined amount is set on the condition that it is at least greater than zero and smaller than an angle (gap angle) θ lk that can be rotated by a gap between the engaged portion Hk and the engaging portion 15 in the engaged state of the engaging portion 15 of the solenoid 16, and is particularly preferably set to the degree of θ lk · (1/4) to θ lk · (3/4) in the above range.

In step S13, in a state where the electric motor 4 has rotated by a predetermined amount, the motor angle is maintained at a substantially constant angle for a predetermined time period in order to ensure the time for which the engagement portion 15 is disengaged. The substantially constant angle is assumed to be constant, although the swing that does not affect the degree of the parking brake release operation is negligible. The predetermined time may be determined based on, for example, a solenoid separation time derived from a stroke amount of solenoid separation, a mass of the coupling portion 15 as the movable portion, a solenoid driving force, and the like, and it is preferable to set the predetermined time in consideration of influences such as a slip resistance, a deviation of the driving force due to a temperature change and an individual difference, a predetermined safety factor, and the like. This operation can be also implemented by angular velocity control using a velocity zero as a motor angular velocity command value.

Then, the electric motor 4 is rotated by a predetermined amount in the pressure reducing direction (step S14), and the release of the locked state is confirmed (step S15). The release of the locked state may be determined, for example, based on a condition that the electric motor 4 is rotated to a pressure-reduced side from the position locked at the time of starting the flow, or may be determined based on a pitch amount or more by which the electric motor 4 is rotated to the pressure-reduced side to rotate the engaged portion Hk.

When it is confirmed that the electric motor 4 is locked, for example, that the rotation of the electric motor 4 is blocked before the above condition is reached (yes in step S15), it is determined that the parking brake release operation is defective. When the release of the locked state is confirmed (no in step S15), the release of the parking brake mechanism PBK is completed. This operation may be angle control in which the motor angle command value is shifted in the pressure reducing direction, or may be angular velocity control in which the motor angular velocity command value is shifted in a predetermined pressure reducing direction.

In fig. 6, a solenoid is assumed in which the engaging portion is projected by the attraction force of the solenoid coil and the engaging portion is separated by the spring reaction force, and therefore, the solenoid is not shown in the drawing, but for example, in a solenoid or a DC motor which is driven bidirectionally in the direction of passing a current, an operation of energizing in the direction of separating the locking mechanism needs to be provided between step S12 and step S13 or in the front and rear.

The operation when each malfunction shown in fig. 5 and 6 occurs can be set as appropriate according to the system requirements. For example, the operation may be retried from a predetermined flow or may be a malfunction, the operation related to the parking brake mechanism may be stopped, or both may be used according to a condition such as the number of retries. Further, a mechanism or the like for transmitting information of occurrence of the malfunction to the driver of the vehicle, the host ECU, or the like may be provided as appropriate.

Further, fig. 5 and 6 show a minimum operation flow of the parking brake operation, and changes are made as needed within a range in which a failure does not occur in the operation flow. For example, a flow path or the like may be separately provided when the parking brake operation is interrupted halfway, or a flow path or the like may be separately provided in which, for example, the inclination of the current position is detected in the automobile and the load of the parking brake is adjusted according to the inclination angle. In addition, the same flow as in fig. 5 and 6 can be applied to other applications such as an electric valve device (fig. 17) and an electric press device described later, for example, by replacing the brake load control with application-dependent changes such as valve flow control and pressure load control.

< example of operation of electric brake device >

Fig. 7 to 12 show, as an example of fig. 4, a configuration example of a part of the reverse input holding control unit 24 and the actuator controller 23. Fig. 7 shows an example in which the actuator controller 23 includes a load controller Ca and an angle controller Cb, and switches the controllers via the switch 25 based on the switching determination of the reverse input hold control unit 24, and derives a motor drive command (motor drive signal) from either one of the controllers. The motor drive command may be any one of motor torque, motor current, and motor voltage, for example, and may have another function such as a torque current converter and a current controller as elements not shown in the drawing.

The load controller Ca has a control calculation function of tracking and controlling the estimated load with respect to a load target value based on any one of the brake operation command and the parking brake load control command. The brake operation command may be, for example, a brake command signal that changes in accordance with the amount of operation of a brake pedal or the like, a control signal from the host ECU 17 (fig. 4) such as a brake command for an autonomous vehicle, a control signal based on antiskid control, anti-sideslip control, emergency automatic braking, or the like, or a function of changing an operation parameter such as a control gain in accordance with the use.

The parking brake load control command may be set as a brake load command for a parking brake operation for applying a predetermined brake load. Based on the switching determination of the reverse-input hold control portion 24, switching is performed between the parking brake load control command and the brake operation command through the switch 26.

The angle controller Cb has a control arithmetic function of tracking and controlling the estimated motor angle with respect to the parking brake angle control command. Further, the angle controller Cb may be not limited to the parking brake application. For example, when a gap control function or the like at the time of brake release is provided as an element other than the illustrated elements, a function of controlling the estimated motor angle in accordance with the motor angle command value for the gap control may be provided, or a function of changing an operation parameter such as a control gain may be provided in accordance with the use.

The reverse input hold control unit 24 has a function of deriving each control signal and control switching signal for locking by the solenoid 16 (fig. 4) in a state where a predetermined braking load is exerted, based on a parking brake command, using at least the load controller Ca and the angle controller Cb.

The solenoid drive command may be a command signal for performing an operation of ON-OFF switching energization of the solenoid coil in a solenoid separated by a spring reaction force, for example. As an example of a specific configuration, the configuration may be made up of an operation element port of a microcomputer or the like, which switches a potential of TTL or the like with respect to a predetermined threshold value to ("1 (high)"/"0 (low)"), and a switching element driver or a switching element itself, which switches on and off an energization switching element (FET, bipolar transistor, or the like) to a solenoid coil in accordance with the high/low of the port signal.

Alternatively, for example, in a solenoid or a DC motor that performs bidirectional driving in accordance with the flow of current, a command signal for switching the energization direction and ON-OFF of each operation of the click mechanism in the flow of protrusion, separation, and stop (non-driving) may be used. As an example of a specific configuration, the bridge circuit may be configured by a bridge circuit including at least four current-carrying switching elements, a port group such as a microcomputer for setting each switching element of the bridge circuit to a predetermined current-carrying and cutoff mode, a predetermined protocol communication port such as SPI, SENT, PWM, or the like, and a bridge circuit control driver.

Fig. 7, 8, and 9 show the same functional configuration, and are in different control states by switching the switches 25 and 26. The switches 25 and 26 are switched by the reverse input hold control unit 24. Fig. 7 shows an example of a normal brake control state, fig. 8 shows an example of a brake load control state at the time of parking brake operation, and fig. 9 shows an example of a motor angle control state at the time of parking brake operation.

Fig. 10 shows an example in which the brake load control function is configured using the angle controller Cb and the predetermined correlation between the brake load and the motor angle without providing a load controller, as compared with the examples of fig. 7 to 9.

As shown in fig. 10, the angle converter 27 has a function of converting the braking load into the motor angle based on the correlation that can derive the motor angle when the predetermined braking load is exerted. The correlation between the braking load and the motor angle may be constructed as needed, for example, based on a previously measured rigidity of an electric brake device using an electric actuator, based on a correlation between the braking load and the motor angle during operation, by means of data fitting, learning, or the like, or may be used in combination.

The motor angle correction amount calculator 28 compares the motor angle obtained via the angle converter 27 with the motor angle corrected by the motor angle corrector 29, which will be described later, based on the estimated load, and derives a motor angle correction amount for making the error between them substantially zero.

The motor angle corrector 29 corrects the current estimated motor angle to a motor angle at which the brake load deviation can be converged to substantially zero, based on the motor angle correction amount calculated by the motor angle correction amount calculator 28. That is, the tracking control of the braking load can be realized as a result of correcting the estimated motor angle by correcting the error in which the correlation between the braking load and the motor angle in the angle converter 27 and the correlation of the actual machine have an error, and performing the tracking control of the corrected motor angle by the angle controller Cb. Note that the configuration in which the motor angle correction amount calculator 28 is not operated (the state in which the multiplexer 31 at the subsequent stage of the motor angle correction amount calculator 28 shown in fig. 10 is connected to "0") is equivalent to the execution of the tracking control of the motor angle in the examples of fig. 7 to 9.

Fig. 10, 11, and 12 show the same functional configuration, and are in different control states by switching the switches 30 and 31. The switches 30 and 31 are switched by the reverse input hold control unit 24. Fig. 10 shows an example of a normal brake load control state, fig. 11 shows an example of a brake load control state during parking brake operation, and fig. 12 shows an example of a motor angle control state during parking brake operation.

Fig. 7 to 12 are conceptual views showing only functional configurations, and elements not shown are appropriately provided according to requirements. The functional blocks are provided for convenience, and can be integrated or divided appropriately in a configuration using hardware or software as the case may be.

In the block diagrams of fig. 7 to 12, only the flow of signals in the function is described, and the operation sequence and timing at the time of mounting are not defined. The order of the calculation may be arbitrarily set as long as the function does not fail, and timing may be appropriately set by introducing multi-rate processing or the like which is executed at a plurality of sampling rates such as calculation at a high speed or a low speed by the function. The present embodiment is not an example of selecting one of them, and a structure in which a part or the whole is combined may be adopted as necessary as long as there is no contradiction in mounting. Fig. 7 to 12 show examples of the parking brake mechanism, but the same configuration as that of fig. 7 to 12 can be applied to other applications such as the electric valve device and the electric pressure device shown in fig. 17 by changing the application.

< example of operation of parking brake mechanism >

Fig. 13 and 14 are views showing operation examples of the parking brake mechanism shown in fig. 1 to 12, respectively. Fig. 13 shows an example of starting the parking brake operation during brake release, i.e., in a state where the clearance control is performed by the motor angle control. At time t1, when the locking operation of the parking brake mechanism is started, the brake load control is executed to increase the brake load to a predetermined parking brake load.

After reaching a predetermined parking brake load at time t2, the control is switched to the motor angle control and the amount is further increased by a predetermined amount. This operation is because, for example, the braking load may be reduced by 1 pitch amount (fig. 3) of the holes of the engaged portion in the process of locking by the reverse input holding mechanism, and the weight of the reduced braking load may be a magnitude depending on the hole pitch, that is, the motor angle. At this time, for example, in a state where the brake load control is maintained at time t2, the brake load weight that can be reduced by the hole pitch amount is determined in advance, and the predetermined brake load obtained by adding the predetermined brake load weight to the predetermined parking brake load may be increased, and then the process of switching to the motor angle control may be performed.

After the predetermined amount of pressurization is completed at time t3, the motor angle is maintained substantially constant until time t 4. At this time, the operation of projecting the engaging portion of the solenoid is performed at the same time. When the engagement portion of the solenoid is kept in the protruding state from time t4, the motor is rotated in the pressure reducing direction. When the positional relationship between the engaged portion and the engaging portion of the solenoid reaches the predetermined position of engagement, the engaged portion is locked by the solenoid, the motor rotation is stopped (time t5), and the locking operation of the parking brake mechanism is completed. Note that, although fig. 13 shows a process of deactivating the motor (the engaging portion is in a state of being engaged with the engaged portion regardless of the torque of the motor) after the lock is completed, for example, a predetermined low-power-consumption standby state such as a state in which the torque is zero or the current is zero may be adopted.

From time t6, the release operation of the parking brake mechanism is started, the motor angle control is switched, and the motor is rotated by a predetermined amount toward the pressure increasing side. In fig. 13, it is assumed that the engaging portion is a solenoid that protrudes due to the attraction force of the solenoid coil and is separated due to the spring reaction force, and the solenoid is not shown in the figure, but for example, in a solenoid, a DC motor, or the like that is bidirectionally driven in accordance with the direction of current, an operation of energizing in the direction of separating the catch mechanism at time t6 or t7 is performed.

From time t7, the motor angle is maintained substantially constant until the engagement portion of the solenoid reliably separates. Then, the motor is rotated in the pressure reducing direction from the time t8, and the motor is rotated in the pressure reducing direction to a pressure reducing direction at least higher than the motor angle in the locked state at a time t9, so that the unlocking is confirmed and the releasing operation of the parking brake mechanism is completed. The operation after time t9 is arbitrary.

Fig. 14 shows an example of the operation of the parking brake mechanism from the start of the brake load control state. In addition, although fig. 13 and 14 show the operation based on the premise that the relative position of the engaged portion and the engaging portion of the electromagnetic element is unknown when the locking operation of the parking brake mechanism is started, when the engaged portion is provided on the motor shaft or the like, the positional relationship of the engaged portion can be grasped in advance, the engaging portion of the electromagnetic element may be protruded by stopping the angle of the motor at a position where the positional relationship of the engaged portion and the engaging portion of the electromagnetic element can be engaged.

< action Effect >

According to the electric actuator DA and the electric brake device 1 described above, when the engaging portion 15 is engaged with or disengaged from the engaged portion Hk that moves in synchronization with the rotor of the electric motor 4, the engagement intermediate control function portion 24a maintains the positional relationship in which the engaged portion Hk and the engaging portion 15 do not contact for a certain period of time required for the operation of the engaging portion 15. In other words, the rotation angle of the electric motor 4 is controlled in accordance with the operation of the engaging portion 15 to hold the engaging portion 15 in the intermediate engagement state with respect to the engaged portion Hk. Accordingly, the engagement portion 15 can be reliably engaged with or disengaged from the engaged portion Hk by the subsequent rotation of the electric motor 4, and the reverse input holding state or the reverse input holding release state can be more reliably shifted. Since the reverse input holding mechanism can be reliably operated by such control, cost reduction can be achieved as compared with the above-described conventional technique having a complicated configuration or the like.

< related to other embodiments >

Next, other embodiments and the like will be described. In the following description, the same reference numerals are given to parts corresponding to the items described earlier in the respective embodiments, and redundant description is omitted. When only a part of the structure is described, the other parts of the structure are the same as those described above unless otherwise specified. The same structure can achieve the same effect. Not only the combinations of the portions specifically described in the respective embodiments but also the embodiments may be partially combined with each other as long as there is no particular obstacle to the combinations.

< example of other Structure of reverse input holding mechanism >

Fig. 15A shows an example in which an engaging member 32 (engaged portion) that rotates in synchronization with the rotation axis of the intermediate gear 13 of the reduction gear 5 is separately provided in the rotation axis direction, and a radial groove mz is provided in the engaging member 32. The groove mz has a contact surface parallel to the linear movement direction of the engagement portion 15 with respect to any rotational direction of the motor. The engaging member 32 provided may be a member that rotates in synchronization with the gear by a shaft fitting shape such as a flat surface processing or a spline processing, or may be a member that is coupled to the gear portion by welding or bonding.

In the example of fig. 15A, as in fig. 2, the engagement portion 15 of the solenoid 16 engages with the groove mz, thereby preventing rotation of the motor, and the engagement state is maintained by the frictional force of the contact surface, and the engagement state is maintained against the reverse input without being affected by the torque of the motor. Fig. 15B shows an example in which the radial grooves mz are provided directly on the gear 13. In this case, the structure can be simplified and the cost can be reduced as compared with the example of fig. 15A.

Fig. 16A shows, as another example, an example in which the solenoid 16 is disposed on the radially outer side of the outer peripheral surface of the engaging member 32 as the engaged portion, facing the outer peripheral surface. In this case, the engaging portion 15 of the solenoid 16 linearly moves in a radial direction orthogonal to the axial direction of the engaged portion. Fig. 16B shows an example in which a plurality of holes ha are provided at equal intervals on the circumference instead of the grooves on the outer circumferential surface of the engaging member 32 as the engaged portion, as compared with the example of fig. 16A. Fig. 16C shows an example in which the hole ha shown in fig. 2 is directly provided in the rotor 4b of the electric motor 4.

The structures of fig. 2 and 15A to 16C may be combined as appropriate within a range where no problem arises in the shape. For example, the shapes shown in fig. 15A, 15B, 16A, and 16B can be applied to the rotor of the motor shown in fig. 16C. In fig. 2 and fig. 15A to 16C, an example in which a solenoid is used as a drive source is shown, but for example, a linear movement structure of a DC motor and a screw may be used. Alternatively, a link mechanism or the like may be provided separately without directly arranging the engaged portion and the solenoid to face each other.

Fig. 17 shows another example in which the electric actuator is applied to an application other than the electric brake device, that is, an example of an electric valve device having a function of locking the flow rate control valve in a predetermined state. The example of fig. 17 differs from the electric brake device 1 (fig. 4) in that the linear movement mechanism is a valve device (for example, a butterfly valve or the like) and the function related to the load control is a function related to the flow rate control. Further, a flow rate command device 17c is used instead of the brake command device 17a (fig. 4), and a valve lock command device 17d is used instead of the parking brake command device 17b (fig. 4).

The motor angle control unit 23b in fig. 17 also includes a structure that can substantially function as an angle control function. For example, the angular control of a predetermined reduction gear that rotates in synchronization with the electric motor 4, or the position control of the position of a linear movement mechanism via a screw lead or the like may be performed. Alternatively, angular velocity control may be applied according to conditions, and for example, angular velocity control in which the position control held at a predetermined position is replaced with angular velocity control in which the velocity is maintained at zero, and angular velocity control in which the position control when the angle is changed under a predetermined condition is replaced with angular velocity control of a predetermined value. Alternatively, these methods may be appropriately used in combination as long as they are within a range in which failure does not occur.

In addition, the functional blocks shown in fig. 4 and 17 are provided only for convenience of description, and the configuration, partition, and the like of hardware or software are not limited. The specific configurations of the software and hardware may be arbitrarily configured within a range not affecting the functions shown in fig. 4 and 17, and the functions of the respective blocks shown in this figure may be unified or divided as necessary. Alternatively, elements other than those shown in the drawings may be added to the extent that the functions of the present drawing are not impaired, and additional controls such as anti-slip control of the electric brake device, pad clearance control at the time of brake release, and anti-sideslip control, and other safety mechanisms may be added as appropriate depending on the system requirements, for example.

As the electric motor 4, for example, a DC motor using a brush, a reluctance motor not using a permanent magnet, an induction motor, or the like can be applied. For example, a planetary gear, a worm gear, a harmonic reducer, or the like may be used as the reducer 5. The linear movement mechanism 6 can use various screw mechanisms such as a planetary screw and a ball screw, and various mechanisms such as a ball ramp that converts a rotational motion into a linear motion by tilting the rotation axis in the circumferential direction.

As described above, the preferred embodiments have been described with reference to the drawings, but various additions, modifications, and deletions can be made within the scope not departing from the spirit of the present invention. Therefore, such a structure is also included in the scope of the present invention.

Description of reference numerals:

reference numeral 1 denotes an electric brake device;

reference numeral 2 denotes a control device;

reference numeral 4 denotes an electric motor;

reference numeral 7 denotes a parking brake mechanism (reverse input holding mechanism);

reference numeral 8 denotes a brake rotor;

reference numeral 9 denotes a friction member;

reference numeral 15 denotes an engaging portion;

reference numeral 16 denotes an actuator (driving source);

reference numeral 21 denotes a load estimation mechanism;

reference numeral 22a denotes a motor angle estimating mechanism;

reference numeral 23a denotes a brake load control unit (load control function unit);

reference numeral 23b denotes a motor angle control section;

reference numeral 24 denotes a reverse input hold control unit;

reference numeral 24a denotes an engagement intermediate control function unit;

symbol Ks represents a snap mechanism;

symbol DA denotes an electric actuator;

symbol Hk denotes an engaged portion.