阅读说明：本技术 电动驱动装置以及电动动力转向装置 (Electric drive device and electric power steering device ) 是由 滨田启二 于 2018-09-07 设计创作，主要内容包括：具备马达壳体侧环状槽部(35)和金属罩侧环状前端部(37),该马达壳体侧环状槽部(35)形成于金属制的马达壳体(11)的、与电动马达部(8)的旋转轴(23)的输出部位于相反侧的端面部(15)的外周面,由向与马达壳体(11)的轴线正交的径向的内侧后退的环状槽构成,该金属罩侧环状前端部(37)形成于将对电动马达部(8)进行控制的电子控制部(9)覆盖的金属罩(12)的开口端,从外侧与马达壳体侧环状槽部(35)的环状槽相对,在金属罩侧环状前端部(37)与马达壳体侧环状槽部(35)相对地配置的状态下,在马达壳体侧环状槽部(35)与金属罩侧环状前端部(37)之间填充有液状密封剂(41),并且在金属罩侧环状前端部(37)的内周面形成有在金属罩(12)的径向上朝向外侧倾斜地扩张的环状倾斜面(37IN)。(The motor is provided with a motor housing side annular groove part (35) and a metal cover side annular front end part (37), the motor housing side annular groove part (35) is formed on the outer peripheral surface of an end surface part (15) of a metal motor housing (11) which is positioned on the opposite side of an output part of a rotating shaft (23) of an electric motor part (8) and is composed of an annular groove which retreats to the inner side of the radial direction orthogonal to the axis of the motor housing (11), the metal cover side annular front end part (37) is formed on the opening end of a metal cover (12) which covers an electronic control part (9) which controls the electric motor part (8), the opening end is opposite to the annular groove of the motor housing side annular groove part (35) from the outer side, and a liquid sealing agent (41) is filled between the motor housing side annular groove part (35) and the metal cover side annular front end part (37) under the state that the metal cover side annular front end part (37) is opposite to the motor housing side annular groove part (35), an annular inclined surface (37IN) which is inclined outward IN the radial direction of the metal cover (12) and is expanded is formed on the inner peripheral surface of the metal cover side annular front end portion (37).)

1. An electric drive device is provided with: a motor case that houses an electric motor that drives a machine control element; an electronic control unit disposed on an end surface side of the motor case opposite to an output unit of a rotation shaft of the electric motor, for driving the electric motor; a cover that covers the electronic control unit; the disclosed device is characterized by being provided with:

a motor case side annular groove portion formed in an outer peripheral surface of the end surface portion of the motor case on an opposite side to the output portion of the rotary shaft of the electric motor, and including an annular groove receding inward in a radial direction orthogonal to an axis of the motor case;

a cover-side annular front end portion formed at an opening end of the cover covering the electronic control unit for controlling the electric motor, the cover-side annular front end portion facing the annular groove of the motor-case-side annular groove portion from outside;

in a state where the cover-side annular leading end portion is disposed to face the motor-housing-side annular groove portion, a liquid sealant is filled between the motor-housing-side annular groove portion and the cover-side annular leading end portion, and an annular inclined surface that expands obliquely outward in a radial direction of the cover is formed on an inner peripheral surface of the cover-side annular leading end portion.

2. The electric drive apparatus according to claim 1,

the cover-side annular tip portion of the cover is bent to form the annular inclined surface.

3. The electric drive apparatus according to claim 1,

the cover-side annular tip portion of the cover is formed with the annular inclined surface by press working or cutting working.

4. The electric drive apparatus according to claim 1,

a radial wall surface of the motor case side annular groove portion is formed along an axis of the motor case.

5. The electric drive apparatus according to claim 1,

a radial wall surface of the motor case-side annular groove portion is formed along the annular inclined surface of the cover-side annular tip portion.

6. An electric power steering device is provided with: an electric motor that applies a steering assist force to a steering shaft based on an output from a torque sensor that detects a turning direction and a turning torque of the steering shaft; a motor case that houses the electric motor; an electronic control unit disposed on an end surface side of the motor case opposite to an output unit of a rotation shaft of the electric motor, for driving the electric motor; a cover that covers the electronic control unit; the disclosed device is characterized by being provided with:

a motor case side annular groove portion formed in an outer peripheral surface of the end surface portion of the motor case on an opposite side to the output portion of the rotary shaft of the electric motor, and including an annular groove receding inward in a radial direction orthogonal to an axis of the motor case;

a cover-side annular front end portion formed at an opening end of the cover covering the electronic control unit for controlling the electric motor, the cover-side annular front end portion facing the annular groove of the motor-case-side annular groove portion from outside;

in a state where the cover-side annular leading end portion is disposed to face the motor housing-side annular groove portion, a liquid sealant is filled between the motor housing-side annular groove portion and the cover-side annular leading end portion, and an annular inclined surface of the cover-side annular leading end portion, which is inclined outward in a radial direction of the cover, is formed on an inner peripheral surface of the cover-side annular leading end portion.

7. The electric power steering apparatus according to claim 6,

the cover-side annular tip portion of the cover is bent to form the annular inclined surface.

8. The electric power steering apparatus according to claim 6,

the cover-side annular tip portion of the cover is formed with the annular inclined surface by press working or cutting working.

9. The electric power steering apparatus according to claim 6,

a radial wall surface of the motor case side annular groove portion is formed along an axis of the motor case.

10. The electric power steering apparatus according to claim 6,

a radial wall surface of the motor case-side annular groove portion is formed along the annular inclined surface of the cover-side annular tip portion.

Technical Field

The present invention relates to an electric drive device and an electric power steering device, and more particularly to an electric drive device and an electric power steering device incorporating an electronic control device.

Background

In the field of general industrial machinery, an electric motor is used to drive a machine control element, but recently, a so-called mechatronic electric drive device has been used in which an electronic control unit, which is configured by a semiconductor element or the like and controls the rotation speed and the rotation torque of the electric motor, is integrally incorporated in the electric motor.

As an example of the electromechanical integrated electric drive device, for example, in an electric power steering device of an automobile, a turning direction and a turning torque of a steering shaft turned by a driver's operation of a steering wheel are detected, and an electric motor is driven to turn in the same direction as the turning direction of the steering shaft based on the detected value, thereby generating a steering assist torque. An Electronic Control Unit (ECU) is provided in the power steering system to Control the electric motor.

As a conventional electric power steering apparatus, for example, an electric power steering apparatus described in japanese patent laying-open No. 2015-134598 (patent document 1) is known. Patent document 1 describes an electric power steering system including an electric motor unit and an electronic control unit. The electric motor of the electric motor unit is housed in a motor case having a cylindrical portion made of an aluminum alloy or the like, and the substrate of the electronic control unit on which the electronic components are mounted is attached to a heat sink functioning as an ECU case disposed on the opposite side of the output shaft in the axial direction of the motor case.

The substrate mounted on the heat sink includes a power supply circuit unit, a power conversion circuit unit having a power switching element such as a MOSFET or an IGBT for drive-controlling the electric motor, and a control circuit unit for controlling the power switching element, and an output terminal of the power switching element and an input terminal of the electric motor are electrically connected via a bus bar.

Then, power is supplied from a power source to an electronic control unit mounted on the heat sink via a connector housing made of synthetic resin, and a detection signal of an operation state or the like is supplied from a detection sensor or the like to the electronic control unit mounted on the heat sink. The connector housing functions as a cover, is fixed to seal and close the heat sink, and is fixed to the outer peripheral surface of the heat sink by fixing screws.

In addition to this, as an electric drive device integrating an electronic control device, an electric brake, an electric hydraulic controller for various hydraulic control, and the like are known, but the electric power steering device will be described as a representative in the following description.

Disclosure of Invention

Technical problem to be solved by the invention

Here, in the electric power steering apparatus of patent document 1, the motor housing, the heat sink, and the connector housing are fastened together by a fixing screw inserted through a fixing portion formed to protrude toward the outer peripheral side.

Further, a sealing member such as an O-ring is used between the motor housing and the heat sink or between the heat sink and the connector housing to achieve liquid tightness. In addition, the fixation between the motor case and the heat sink or between the heat sink and the connector housing is achieved by fixing screws. When the heat sink is not used, an O-ring is interposed between the motor housing and the connector housing and the motor housing and the connector housing are fixed by a fixing screw.

However, in the case of automobiles, there are cases where the automobiles travel on roads on which snow melting agents and the like are scattered and where the automobiles travel on roads near coastlines. Therefore, when the vehicle travels on a road after melting snow or a road near a coastline where rain is present, salt water often enters under the floor of the vehicle. Therefore, in the case of a liquid-tight sealing structure using only an O-ring, a fitting gap is substantially formed before reaching a region where the O-ring is disposed. Therefore, the brine enters the fitting gap, the O-ring housing is corroded, and in the worst case, a liquid-tight failure may occur, and the brine may enter the inside, which may deteriorate the reliability of the electric device.

Therefore, in order to solve such a problem, for example, as shown in fig. 16, a configuration is conceivable in which an electronic control unit is disposed on an end surface portion of a motor case, and an open end of a metal cover covering the electronic control unit is joined to the end surface of the motor case via a liquid sealant.

In fig. 16, an annular sealant accommodating groove 61 that recedes inward is formed in the outer peripheral surface of the motor case 60, and after the liquid sealant 62 is filled into the sealant accommodating groove 61, the sealant accommodating groove 61 is covered with a metal cover side annular tip portion 64 of a metal cover 63, whereby the motor case 60 and the metal cover 63 can be joined together in a liquid-tight manner.

The liquid sealant 62 has adhesiveness and viscosity to maintain the shape during application, and thus the metal cover side annular tip portion 64 and the sealant accommodating groove 61 can be joined together by the liquid sealant 62. However, since the adhesiveness and the viscosity are provided, when the metal cover side annular tip portion 64 is pressed toward the end surface side of the motor housing 60 in the direction of the arrow, a pulling force acts in one direction (downward arrow direction in the drawing) of the liquid sealant 62 in contact with the inner peripheral surface of the metal cover side annular tip portion 64.

Therefore, when the metal cover side annular tip portion 64 is pushed toward the end surface side of the motor case 60, the liquid sealant 62 filled in the sealant accommodating groove 61 is pulled and moved along the movement of the inner peripheral surface of the metal cover side annular tip portion 64. Thus, a space P in which the liquid sealant 62 does not exist in the sealant accommodating groove 61 appears at the interface between the liquid sealant 62 and the inner peripheral side of the metal cap side annular tip portion 64.

This eventually leads to a problem that the seal length is shortened, and the possibility of salt water or the like entering the metal cover 63 is increased, thereby impairing the mechanical and electrical reliability.

Therefore, an electric drive device and an electric power steering device that can cope with such a problem are desired. The main object of the present invention is to provide a novel electric drive device and electric power steering device with improved mechanical and electrical reliability.

Technical solution for solving technical problem

The present invention is characterized by comprising a motor housing-side annular groove portion formed in an outer peripheral surface of an end surface portion of a motor housing located on an opposite side to an output portion of a rotary shaft of an electric motor, the motor housing-side annular groove portion being constituted by an annular groove that recedes inward in a radial direction orthogonal to an axis of the motor housing, and a cover-side annular tip portion formed at an opening end of a cover covering an electronic control portion that controls the electric motor, the cover-side annular tip portion facing the annular groove of the motor housing-side annular groove portion from outside, the cover-side annular tip portion being arranged to face the motor housing-side annular groove portion, a liquid sealant being filled between the motor housing-side annular groove portion and the cover-side annular tip portion, and an annular inclined surface that extends obliquely outward in the radial direction of the cover being formed on an inner peripheral surface of the cover-side annular tip portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, since the annular inclined surface which is inclined and expanded outward in the radial direction of the cover is formed on the inner peripheral surface of the cover-side annular tip portion, when the cover-side annular tip portion is pressed against the end surface side of the motor housing, the pressing force acting on the liquid sealant filled in the motor housing-side annular groove portion is dispersed, whereby the liquid sealant can be prevented from being moved along the inner peripheral surface of the cover-side annular tip portion by being pulled, and the generation of a space in which the liquid sealant does not exist can be prevented.

Drawings

Fig. 1 is an overall perspective view of a steering device to which an example of the present invention is applied.

Fig. 2 is a perspective view showing the overall shape of an electric power steering apparatus according to an embodiment of the present invention.

Fig. 3 is an exploded perspective view of the electric power steering apparatus shown in fig. 2.

Fig. 4 is an external perspective view of the motor housing shown in fig. 3.

Fig. 5 is an axial sectional view of the motor housing shown in fig. 4.

Fig. 6 is an external perspective view showing a state in which the power conversion circuit unit is placed and fixed on the motor case shown in fig. 4.

Fig. 7 is an external perspective view showing a state where the power circuit unit is placed and fixed on the motor case shown in fig. 6.

Fig. 8 is an external perspective view showing a state where the control circuit unit is placed and fixed on the motor case shown in fig. 7.

Fig. 9 is an external perspective view showing a state where the connector terminal assembly is placed and fixed on the motor housing shown in fig. 8.

Fig. 10 is an external view of the electric power steering apparatus after the metal cover and the motor case of the embodiment of the present invention are pressed and fixed.

Fig. 11 is a main part sectional view of the electric power steering apparatus before the metal cover shown in fig. 10 is pressed and fixed to the motor case.

Fig. 12 is a sectional view showing a state where the motor case shown in fig. 11 is assembled with a metal cover.

Fig. 13 is a cross-sectional view showing the shape of the inclined surface of the tip end portion of the metal cover shown in fig. 11.

Fig. 14 is a cross-sectional view showing another shape of the annular groove portion of the motor housing shown in fig. 11.

Fig. 15 is a cross-sectional view showing another shape of the inclined surface of the tip end portion of the metal cover shown in fig. 11.

Fig. 16 is a cross-sectional view showing an enlarged cross-section of a joint portion between a motor case and a metal cover by a liquid sealant for explaining a technical problem to be solved by the present invention.

Detailed Description

The present invention is not limited to the following embodiments, and various modifications and application examples are included within the scope of the technical concept of the present invention.

Before describing an embodiment of the present invention, a configuration of a steering device as an example to which the present invention is applied will be described with reference to fig. 1.

First, a steering device for steering the front wheels of an automobile will be described. The steering device 1 is configured as shown in fig. 1. A pinion gear, not shown, is provided at the lower end of the steering shaft 2 coupled to a steering wheel, not shown, and the pinion gear meshes with a rack, not shown, that is long in the left-right direction of the vehicle body. Tie rods 3 for steering the front wheels in the right-left direction are connected to both ends of the rack, and the rack is covered with a rack housing 4. A rubber bush 5 is provided between the rack housing 4 and the tie rod 3.

An electric power steering device 6 is provided to assist torque when the steering wheel is turned. That is, a torque sensor 7 that detects the turning direction and the turning torque of the steering shaft 2, an electric motor unit 8 that applies a steering assist force to the rack via a gear 10 based on the detection value of the torque sensor 7, and an Electronic Control Unit (ECU) 9 that controls an electric motor disposed in the electric motor unit 8 are provided. Three portions of the outer peripheral portion of the electric motor portion 8 on the output shaft side of the electric power steering apparatus 6 are connected to a gear 10 via unillustrated screws, and an electronic control portion 9 is provided at a position opposite to the output shaft of the electric motor portion 8.

In the electric power steering apparatus 6, when the steering shaft 2 is rotationally operated in either direction by the operation of the steering wheel, the torque sensor 7 detects the rotational direction and the rotational torque of the steering shaft 2, and the control circuit unit calculates the drive operation amount of the electric motor based on the detected values. Based on the calculated drive operation amount, the electric motor is driven by the power switching element of the power conversion circuit unit, and the output shaft of the electric motor is rotated so as to drive the steering shaft 2in the same direction as the operation direction. The rotation of the output shaft is transmitted from a pinion gear not shown to a rack gear not shown via a gear 10, and the vehicle is steered. Since these structures and functions are well known, further description thereof will be omitted.

In fig. 16, since the liquid sealant 62 has adhesiveness and viscosity, when the metal cover side annular tip portion 64 is pressed toward the end surface side of the motor housing 60 in the direction of the arrow, a pulling force acts on the liquid sealant 62 in contact with the inner peripheral surface of the metal cover side annular tip portion 64.

Therefore, when the metal cover side annular tip portion 64 is pressed against the end surface side of the motor case 60, a phenomenon occurs in which the liquid sealant 62 filled in the sealant accommodating groove 61 moves so as to be pulled along the movement of the inner peripheral surface of the metal cover side annular tip portion 64. As a result, a space P in which the liquid sealant 62 is not present is created in the sealant storage groove 61, and as a result, a sealing length becomes short, and the possibility that salt water or the like enters the metal cover 63 becomes high, which causes a problem that mechanical and electrical reliability is lowered.

In view of such a background, the present invention proposes an electric power steering apparatus having the following configuration.

In the present invention, the motor case side annular groove portion is formed in the outer peripheral surface of the end surface portion of the metal motor case on the opposite side to the output portion of the rotating shaft of the electric motor, and is constituted by an annular groove receding inward in the radial direction orthogonal to the axis of the motor case, the metal cover side annular front end portion is formed at an opening end of a metal cover covering an electronic control portion for controlling the electric motor, and is opposed to the annular groove of the motor housing side annular groove portion from the outside, a liquid sealant is filled between the motor case side annular groove portion and the metal cover side annular tip portion in a state where the metal cover side annular tip portion is disposed to face the motor case side annular groove portion, an annular inclined surface that is inclined outward in the radial direction of the metal cover is formed on the inner peripheral surface of the metal cover side annular tip portion.

Accordingly, since the annular inclined surface which is inclined outward in the radial direction of the metal cover is formed on the inner peripheral surface of the metal cover-side annular tip portion, when the metal cover-side annular tip portion is pressed against the end surface side of the motor housing, the pressing force acting on the liquid sealant filled in the motor housing-side annular groove portion is dispersed, whereby the liquid sealant can be prevented from moving along the inner peripheral surface of the metal cover-side annular tip portion in a pulling manner, and the occurrence of a space in which the liquid sealant does not exist can be prevented.