阅读说明：本技术 旋转式致动器 (Rotary actuator ) 是由 粂干根 木村纯 角弘之 于 2019-09-19 设计创作，主要内容包括：用于车辆的线控换挡系统(11)的旋转式的致动器(10)具备马达(30)、与马达(30)的旋转轴(33)平行地配置的输出轴(40)、和将马达(30)的旋转减速并向输出轴(40)传递的减速机构(50)。减速机构(50)包括设在旋转轴(33)的旋转轴心(AX1)上的传动齿轮(53)、以及设在输出轴(40)的旋转轴心(AX3)上并与传动齿轮(53)啮合的从动齿轮(54)。从动齿轮(54)是与输出轴(40)不同的部件,与输出轴(40)游隙嵌合。(A rotary actuator (10) for a shift-by-wire system (11) of a vehicle is provided with a motor (30), an output shaft (40) arranged parallel to a rotating shaft (33) of the motor (30), and a speed reduction mechanism (50) that reduces the speed of rotation of the motor (30) and transmits the reduced speed to the output shaft (40). The speed reduction mechanism (50) includes a transmission gear (53) provided on a rotation axis (AX1) of the rotation shaft (33), and a driven gear (54) provided on a rotation axis (AX3) of the output shaft (40) and meshing with the transmission gear (53). The driven gear (54) is a member different from the output shaft (40), and is fitted to the output shaft (40) with play.)

1. Rotary actuator for a shift-by-wire system (11) of a vehicle,

the disclosed device is provided with:

a motor (30);

an output shaft (40) disposed parallel to the rotating shaft (33) of the motor; and

a speed reduction mechanism (50) for reducing the speed of the rotation of the motor and transmitting the rotation to the output shaft;

the speed reduction mechanism includes a transmission gear (53) provided on an axial center (AX1) of the rotating shaft, and a driven gear (54) provided on an axial center (AX3) of the output shaft and meshing with the transmission gear;

the driven gear is a member different from the output shaft, and is fitted to the output shaft with play.

2. The rotary actuator of claim 1,

the rotary actuator further comprises a rotational position detection unit (80), wherein the rotational position detection unit (80) comprises a magnetic circuit unit (81) and a magnetic sensor (82);

the magnetic circuit portion is provided on the output shaft or a member that rotates integrally with the output shaft.

3. The rotary actuator of claim 1 or 2,

the driven gear is provided with a 1 st engaging part (74) on the inner circumference;

the output shaft is provided with a 2 nd engaging part (44) on the outer peripheral part, and the 2 nd engaging part (44) can be relatively rotatably engaged with the 1 st engaging part corresponding to the play;

the driven gear can be fitted to the output shaft only within a predetermined angular range including the play.

4. The rotary actuator of claim 3,

the 1 st engaging part is an internal tooth part having a plurality of internal teeth (73) arranged in the circumferential direction;

the 2 nd engagement portion is an external tooth portion having a plurality of external teeth (43) arranged in the circumferential direction;

the inner tooth part is provided with a tooth missing part (76) at one part in the circumferential direction;

the external tooth portion has a coupling tooth (45) at a portion corresponding to the missing tooth portion, the coupling tooth connecting the pair of external teeth with the missing tooth portion therebetween.

5. The rotary actuator of any one of claims 1 to 4,

a meshing section (75) of the driven gear that meshes with the transmission gear and a play fitting section (74) that fits with the output shaft are arranged so that the axial positions thereof overlap each other.

6. The rotary actuator of any one of claims 1 to 5,

the driven gear is supported in the axial direction so as to be sandwiched between a 1 st support part (48) and a 2 nd support part (49).

Technical Field

The present invention relates to rotary actuators.

Background

Conventionally, a rotary actuator used as a drive unit of a shift-by-wire system of a vehicle is known. Patent document 1 discloses a two-axis actuator having an output shaft arranged parallel to a rotation axis of a motor. A speed reduction mechanism is disposed between the motor and the output shaft. The speed reduction mechanism has a planetary gear speed reduction portion including a sun gear and an internal gear, and a parallel shaft type speed reduction portion including a transmission gear and a driven gear. The driven gear and the output shaft are molded articles of the same member.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2018/079418

Disclosure of Invention

Further, when the output shaft position of the actuator is stopped in a state where the locking portion of the stopper spring is positioned before the valley of the stopper rod at the time of switching the shift range, the locking portion falls into the valley position of the stopper rod by the spring force of the stopper spring. The depression range by the torque of the spring force (hereinafter referred to as detent torque) becomes narrow as the driven torque of the actuator becomes larger. Therefore, when the driven torque is large, high accuracy is required for the stop control of the output shaft position of the actuator. Although it is conceivable to increase the detent torque, in this case, the required torque for the actuator becomes high, which is not preferable because the volume of the actuator increases.

In patent document 1, a play is secured by a fitting portion between the output shaft and the manual spindle, which is advantageous for reduction of the driven torque. However, there is a concern that the play may be reduced by the influence of inclination, shaft misalignment, and deviation of the fitting portion at the time of assembling the manual stem.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotary actuator capable of mitigating the stop control accuracy of the output shaft position.

The present invention is a rotary actuator used for a shift-by-wire system (11) of a vehicle, comprising: a motor; an output shaft disposed parallel to a rotation shaft of the motor; and a speed reduction mechanism for reducing the speed of the rotation of the motor and transmitting the rotation to the output shaft. The speed reducing mechanism comprises a transmission gear arranged on the axis of the rotating shaft and a driven gear arranged on the axis of the output shaft and meshed with the transmission gear. The driven gear is a member different from the output shaft, and is fitted to the output shaft with play.

In this way, the backlash is set (that is, a clearance is intentionally provided) between the driven gear and the output shaft in the actuator to reduce the driven torque and enlarge the sinking range, thereby reducing the stop control accuracy of the output shaft position.

Further, the detent torque can be reduced, and the required torque of the actuator and the load on the actuator side and the detent side at the time of shift range switching can be reduced.

Here, when the projection of the sun gear and the through hole of the transmission gear are provided for torque transmission, the through hole can be made as an elongated hole from a circular hole to secure a play. However, there is a problem that the driven torque is increased by the influence of friction of a gear meshing portion between the transmission gear and the driven gear, friction of a bearing of the transmission gear, and the like. Further, the long hole increases the processing cost. Further, in the case where the number of through holes needs to be reduced spatially, there is a possibility that the torque transmission efficiency is lowered.

In view of the above problem, in the present embodiment, by providing a clearance between the driven gear and the output shaft, it is not necessary to lengthen the through-holes and reduce the number of through-holes.

In addition, in the present embodiment in which the driven gear and the output shaft are formed separately, the driven gear and the output shaft can be formed into a simple shape, and the processing cost can be reduced, as compared with a conventional molded article in which the driven gear and the output shaft are the same component.

In the present specification, the "member that rotates integrally with the output shaft" refers to a member that rotates together without relative rotation with respect to the output shaft, and is, for example, a manual shaft lever of a shift range switching mechanism.

Drawings

The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

Fig. 1 is a schematic view showing a shift-by-wire system to which a rotary actuator of an embodiment is applied.

Fig. 2 is a diagram illustrating the shift-position switching mechanism of fig. 1.

Fig. 3 is a cross-sectional view of the rotary actuator of fig. 1.

Fig. 4 is an enlarged sectional view of the driven gear and the output shaft of fig. 3.

Fig. 5 is a view of the driven gear and the output shaft of fig. 4 as viewed from the direction of arrow V.

Fig. 6 is a sectional view showing the driven gear of fig. 4.

Fig. 7 is a view of the driven gear of fig. 6 as viewed from the direction of arrow VII.

Fig. 8 is a sectional view showing the output shaft of fig. 4.

Fig. 9 is a view of the output shaft of fig. 6 as viewed from the direction of arrow IX.

Fig. 10 is an enlarged view of the X portion of fig. 5.

Fig. 11 is an enlarged view of a portion XI of fig. 3.

Detailed Description

[ one embodiment ]

A rotary actuator (hereinafter referred to as an actuator) according to an embodiment will be described below with reference to the drawings. The actuator is used as a drive portion of a shift-by-wire system of a vehicle.

(Shift-by-wire System)

First, the structure of the shift control system will be described with reference to fig. 1 and 2. As shown in fig. 1, the shift-by-wire system 11 includes a shift operation device 13 that commands a shift range of a transmission 12, an actuator 10 that operates a shift range switching mechanism 14 of the transmission 12, a drive circuit 15 that energizes the actuator 10, and a control circuit 17. The control circuit 17 controls the drive circuit 15 according to a command signal for the shift position to drive the actuator 10. The drive circuit 15 and the control circuit 17 constitute an electronic control unit (hereinafter referred to as ECU) 18.

As shown in fig. 2, the shift range switching mechanism 14 includes: a shift position switching valve 20 that controls supply of hydraulic pressure to a hydraulic operating mechanism in the transmission 12; a detent spring 21 and a detent lever 22 for holding the shift position; a parking lever 25 that locks rotation of the output shaft by fitting a parking column 24 to a parking gear 23 of the output shaft of the transmission 12 when the shift range is switched to the parking range; and a manual shaft 26 integrally rotated with the stopper lever 22.

The shift-position switching mechanism 14 rotates the stopper lever 22 together with the manual shaft 26, and moves the valve body 27 of the shift-position switching valve 20 coupled to the stopper lever 22 and the parking lever 25 to a position corresponding to the target shift position. In the shift-by-wire system 11, the actuator 10 is coupled to the manual shaft 26 in order to electrically shift the shift range.

(actuator)

Next, the structure of the actuator 10 will be described. As shown in fig. 3, the actuator 10 includes a motor 30 as a power generation source, an output shaft 40 arranged in parallel to the motor 30, a reduction mechanism 50 that reduces the rotation of the motor 30 and transmits the reduced rotation to the output shaft 40, and a housing 60 that houses the motor 30, the output shaft 40, and the reduction mechanism 50.

The housing 60 includes a cylindrical upper housing portion 61 and a cover-shaped lower housing portion 62. The upper case 61 has a partition 65 formed between one end 63 and the other end 64. A substrate 66 on which a drive circuit and a control circuit (see fig. 1) are mounted is provided inside the one end portion 63. The base plate 66 is fixed to the partition wall 65 by, for example, thermal caulking. The base plate 66 is covered with a cover plate 67 made of iron, thereby ensuring shielding. The lower housing portion 62 is assembled to the other end portion 64. The lower case portion 62 forms a cylindrical protruding portion 69 protruding to the opposite side of the upper case portion 61. The control lever 26 is disposed so as to insert the cylindrical protrusion 69 therethrough.

The motor 30 includes a stator 31 press-fitted into a plate case 68 fixed to the other end 64, a rotor 32 provided inside the stator 31, and a rotary shaft 33 that rotates around a rotation axis AX1 together with the rotor 32. The rotary shaft 33 is rotatably supported by the bearing 34 provided in the plate case 68 and the bearing 35 provided in the lower case 62. The rotary shaft 33 has an eccentric portion 36 eccentric to the rotation axis AX1 on the lower housing portion 62 side with respect to the rotor 32. The motor 30 can be rotated in both directions by controlling the current supplied to the three-phase windings 38 constituting the stator 31 by a control circuit (see fig. 1), and can be stopped at a desired rotational position. The cover plate 67 has a through hole in which the plug 39 is mounted. The rotation shaft 33 can be manually rotated by removing the plug 39 at the time of failure.

The reduction mechanism 50 includes an internal gear 51, a sun gear 52, a transmission gear 53, and a driven gear 54. The internal gear 51 is provided on the rotation axis AX1, and is press-fitted and fixed to the lower case portion 62. The sun gear 52 is supported rotatably about an eccentric axis AX2 by a bearing 55 fitted to the eccentric portion 36, and is meshed with the ring gear 51 in an inscribed manner. When the rotation shaft 33 rotates, the sun gear 52 performs a planetary motion of rotating around the eccentric axis AX2 while revolving around the rotation axis AX 1. The rotation speed of the sun gear 52 at this time is reduced with respect to the rotation speed of the rotary shaft 33. The sun gear 52 has a through hole 56 for transmitting rotation, which penetrates in the axial direction.

The transmission gear 53 is provided on the rotation axis AX1 between the rotor 32 and the sun gear 52, and is supported rotatably about the rotation axis AX1 by a bearing 57 fitted to the rotation shaft 33. Further, the transmission gear 53 has a projection 58 for rotation transmission inserted in the through hole 56. The rotation of the sun gear 52 is transmitted to the transmission gear 53 by the engagement of the through hole 56 and the projection 58. The through hole 56 and the projection 58 constitute a transmission mechanism 59. The driven gear 54 is provided on a rotation axis AX3 parallel to the rotation axis AX1 and coaxial with the cylindrical protrusion 69, and is meshed with the transmission gear 53 in an externally-contacting manner. The driven gear 54 rotates about the rotation axis AX3 while the transmission gear 53 rotates about the rotation axis AX 1. The rotational speed of the driven gear 54 at this time is reduced relative to the rotational speed of the transmission gear 53.

The output shaft 40 is formed in a cylindrical shape and is provided on the rotation axis AX 3. The partition wall 65 has a through support hole 89 coaxial with the rotation axis AX 3. The output shaft 40 is supported rotatably about a rotation axis AX3 by the 1 st flanged sleeve 46 fitted into the through support hole 89 and the 2 nd flanged sleeve 47 fitted inside the cylindrical protruding portion 69. The control lever 26 is inserted into the output shaft 40, and is rotatably and transmissively coupled to the output shaft 40 by spline fitting, for example.

(driven gear, output shaft)

Next, the structure of the driven gear 54, the output shaft 40, and their peripheral portions will be described. As shown in fig. 3 to 5, the driven gear 54 is a member different from the output shaft 40, and is fitted to the output shaft 40 with play.

As shown in fig. 4 to 7, the driven gear 54 includes an annular portion 71 fitted to the output shaft 40 and a gear plate portion 72 protruding radially outward from the annular portion 71. The ring portion 71 forms an internal tooth portion 74 having a plurality of internal teeth 73 arranged in the circumferential direction. The gear plate portion 72 is plate-shaped, and only the meshing portion 75 meshing with the transmission gear 53 is made thick to ensure gear strength. The meshing portion 75 and the internal tooth portion 74 as a "loose fitting portion" are arranged so as to overlap each other in axial position.

As shown in fig. 4, 5, 8, and 9, the output shaft 40 has an external tooth portion 44 having a plurality of external teeth 43 arranged in the circumferential direction formed between the one end portion 41 and the other end portion 42. The outer teeth 43 have a circumferential width smaller than a circumferential width of a gap between the adjacent pair of inner teeth 73. The external toothing 44 and the internal toothing 74 engage in a relatively rotatable manner in accordance with play (i.e. intentionally provided play). The rotation of the driven gear 54 is transmitted to the output shaft 40 via the internal tooth portion 74 and the external tooth portion 44.

As shown in fig. 10, the internal tooth portion 74 has a tooth-missing portion 76 at one circumferential portion. That is, the plurality of internal teeth 73 are arranged at equal intervals in the circumferential direction, and only one portion of the plurality of internal teeth 73 does not have the internal teeth 73. The outer teeth 44 have coupling teeth 45 at a portion corresponding to the tooth-missing portion 76, which couple the pair of outer teeth 43 across the portion. In the present embodiment, the coupling teeth 45 connect the root portions of the pair of external teeth 43 to each other. The driven gear 54 can be fitted to the output shaft 40 only within a predetermined angular range including a backlash.

As shown in fig. 11, one end portion 41 of the output shaft 40 is rotatably supported by the 1 st flanged sleeve 46. The other end 42 of the output shaft 40 is rotatably supported by the 2 nd flanged sleeve 47. The driven gear 54 is axially supported so as to be sandwiched between the 1 st flange portion 48 of the 1 st flanged sleeve 46 and the 2 nd flange portion 49 of the 2 nd flanged sleeve 47. In another embodiment, the driven gear 54 may be supported in the axial direction so as to be sandwiched between a pair of support portions such as the housing 60 and another plate.

The actuator 10 further includes a rotational position detecting unit 80, and the rotational position detecting unit 80 includes a magnetic circuit unit 81 and a magnetic sensor 82. The magnetic circuit portion 81 is attached to the output shaft 40. Specifically, the magnetic circuit portion 81 is formed by integrally molding the holding body 83 and the magnet 84. The position of the holding body 83 in the thrust (thrust) direction is regulated by the upper case portion 61, and the position in the radial direction is regulated by the output shaft 40. The rotational position detecting unit 80 detects the rotational position of the output shaft 40 and the manual stem 26 that rotates integrally therewith, and outputs the detected rotational position to the ECU 18. In another embodiment, the magnetic circuit portion may be provided on the output shaft or a member (e.g., a manual shaft) that rotates integrally with the output shaft. For example, the magnetic circuit portion may be mounted to a manual shaft. The holding body of the magnetic circuit portion may be formed of the same component as the output shaft or the manual shaft, and the magnet of the magnetic circuit portion may be integrally fixed (for example, bonded, integrally formed, or the like) to the holding body.

The holding body 83 is inserted inside the one end portion 41. An O-ring 85 is provided between the holder 83 and the one end portion 41. The end of the holding body 83 on the output shaft 40 side has a bottom hole 86. A spring 87 is inserted into the bottomed hole 86. The spring 87 holds the facing portion 28 formed at the end of the manual stem 26 by a spring force, and functions as a play elimination mechanism with the manual stem 26.

An X-ring 88 is provided between the other end 42 of the output shaft 40 and the cylindrical protruding portion 69. Conventionally, a structure in which sealing is performed by a sealing member provided between an actuator and a transmission case of a transmission is known. However, by providing the X-ring 88 at the above position, the sealing performance can be ensured by the actuator 10 alone.

(Effect)

As described above, in the present embodiment, the actuator 10 includes the motor 30, the output shaft 40 disposed parallel to the rotary shaft 33 of the motor 30, and the reduction mechanism 50 that reduces the rotation of the motor 30 and transmits the reduced rotation to the output shaft 40. The reduction mechanism 50 includes a transmission gear 53 provided on the rotation axis AX1 of the rotation shaft 33, and a driven gear 54 provided on the rotation axis AX3 of the output shaft 40 and meshing with the transmission gear 53. The driven gear 54 is a member different from the output shaft 40, and is fitted to the output shaft 40 with play.

In this way, the backlash between the driven gear 54 and the output shaft 40 is set in the actuator 10 to reduce the driven torque and expand the sinking range, thereby reducing the stop control accuracy of the output shaft position.

Further, the detent torque can be reduced, and the required torque of the actuator 10 and the load on the actuator 10 side and the detent lever 22 side at the time of shifting gear shift can be reduced.

Here, when the projection of the sun gear and the through hole of the transmission gear are provided for torque transmission, the through hole can be made as an elongated hole from a circular hole to secure a play. However, there is a problem that the driven torque is increased by the influence of friction of a gear meshing portion between the transmission gear and the driven gear, friction of a bearing of the transmission gear, and the like. Further, the long hole increases the processing cost. Further, in the case where the number of through holes needs to be reduced spatially, there is a possibility that the torque transmission efficiency is lowered.

In view of the above, in the present embodiment, by providing a play between the driven gear 54 and the output shaft 40, it is no longer necessary to lengthen the through-holes and reduce the number of through-holes.

In addition, in the present embodiment in which the driven gear 54 and the output shaft 40 are formed separately, the driven gear 54 and the output shaft 40 can be formed into a simple shape, and the processing cost can be reduced, as compared with a conventional molded product in which the same member is used as the driven gear and the output shaft.

In the present embodiment, the actuator 10 further includes a rotational position detecting unit 80 including a magnetic circuit unit 81 and a magnetic sensor 82. The magnetic circuit portion 81 is attached to the output shaft 40. This allows the position of the manual spindle 26 as the torque output target to be directly detected.

In the present embodiment, the driven gear 54 is formed with an internal tooth portion 74 having a plurality of internal teeth 73 arranged in the circumferential direction. The output shaft 40 has an external gear portion 44 having a plurality of external teeth 43 arranged in the circumferential direction and engaging with the internal gear portion 74 so as to be relatively rotatable in accordance with play. The internal teeth 74 have a tooth missing portion 76 at one circumferential point. The outer teeth 44 have coupling teeth 45 at a portion corresponding to the tooth-missing portion 76, which couple the pair of outer teeth 43 across the portion. This enables the driven gear 54 and the output shaft 40 to be assembled only at a specific relative rotational position. Therefore, erroneous assembly of the rotational position can be prevented.

In the present embodiment, the meshing portion 75 of the driven gear 54 with the transmission gear 53 and the internal gear portion 74 are disposed so as to overlap each other in the axial direction position. Thereby, the falling of the driven gear 54 is suppressed.

In the present embodiment, the actuator 10 further includes a 1 st flanged sleeve 46 that supports the one end portion 41 of the output shaft 40, and a 2 nd flanged sleeve 47 that supports the other end portion 42 of the output shaft 40. The driven gear 54 is axially supported so as to be sandwiched between the 1 st flange portion 48 of the 1 st flanged sleeve 46 and the 2 nd flange portion 49 of the 2 nd flanged sleeve 47. This restricts the driven gear 54 in the axial direction, and prevents the tilting.

In the present embodiment, although the magnets of the stator and the rotor are not shown in fig. 2 and the like, the motor 30 is configured to generate cogging torque. When the cogging torque is generated in this way, the driven torque of the actuator 10 becomes further large. Therefore, the problem that high accuracy is required for the stop control of the output shaft position is more pronounced, but this problem is effectively eliminated in the case of the present embodiment.

[ other embodiments ]

In another embodiment, the internal gear may be a molded product of the same member as the lower housing portion. In another embodiment, the free-play fitting between the driven gear and the output shaft may be achieved by, for example, a positioning convex portion and a positioning concave portion (e.g., a key groove).

The present invention is described based on the embodiments, but the present invention is not limited to the embodiments and the structure. The present invention also includes various modifications and modifications within the equivalent scope. In addition, various combinations and forms, and further, other combinations and forms including only one element, more than one element, or less than one element are also within the scope and spirit of the present invention.