Electric drive device and electric power steering device

文档序号：1439976 发布日期：2020-02-14 浏览：6次中文

阅读说明：本技术 电动驱动装置及电动动力转向装置 (Electric drive device and electric power steering device ) 是由原秀幸元田晴晃中野和彦萩原克将馆山哲郎于 2018-03-07 设计创作，主要内容包括：提供一种提高机械及电气可靠性并且减小外观形状而降低重量的新式的电动驱动装置及电动动力转向装置。具备：马达外壳侧环状卡合部(40),其形成在金属制的马达外壳(11)的与电动马达的旋转轴的输出部(14)相反的一侧的端面部的外周面；金属罩侧环状卡合部(38),其形成在对控制电动马达的电子控制部进行覆盖的金属罩(12)的开口端(37),并且与马达外壳侧环状卡合部(40)卡合；在将金属罩侧环状卡合部(38)卡合于马达外壳侧环状卡合部(40)的状态下,通过不使用固定螺钉的固定手段来固定金属罩(12)和马达外壳(11),从而形成固定区域部,在固定区域部(38、40)与金属罩的开口端(37)之间形成有填充了液状密封剂(41)的密封区域部。(Provided are a novel electric drive device and an electric power steering device which improve mechanical and electrical reliability and reduce the weight by reducing the external shape. The disclosed device is provided with: a motor housing-side annular engaging portion (40) formed on the outer peripheral surface of an end surface portion of the metal motor housing (11) on the side opposite to the output portion (14) of the rotating shaft of the electric motor; a metal cover side annular engaging portion (38) which is formed at an opening end (37) of a metal cover (12) that covers an electronic control portion that controls the electric motor, and which engages with a motor case side annular engaging portion (40); a metal cover (12) and a motor housing (11) are fixed by a fixing means without using a fixing screw in a state where a metal cover side annular engaging portion (38) is engaged with a motor housing side annular engaging portion (40), thereby forming a fixed region portion, and a seal region portion filled with a liquid sealant (41) is formed between the fixed region portions (38, 40) and an opening end (37) of the metal cover.)

1. An electric drive device is characterized by comprising: a metal motor case that houses an electric motor that drives a mechanical system control element; an electronic control unit disposed on one side of an end surface portion of the motor case on the opposite side of an output portion of the rotary shaft of the electric motor, and including a control circuit unit for driving the electric motor, a power supply circuit unit, and a power conversion circuit unit; a metal cover covering the electronic control unit;

the electric drive device is formed with: a motor case side annular engaging portion formed on an outer peripheral surface of an end surface portion of the motor case on a side opposite to an output portion of a rotating shaft of the electric motor; a metal cover side annular engaging portion formed at an opening end of the metal cover and engaged with the motor case side annular engaging portion;

the metal cover side annular engaging portion and the annular engaging portion are fixed by a fixing means without using a fixing screw in a state where the metal cover side annular engaging portion is engaged with the motor case side annular engaging portion, thereby forming a fixed region portion, and a seal region portion filled with a liquid sealant is formed between the fixed region portion and the opening end of the metal cover.

2. The electric drive of claim 1,

the fixing region portion is formed by press-fitting and caulking a wall surface of the metal cover side annular engaging portion into a caulking recess formed in the motor case side annular engaging portion.

3. The electric drive of claim 2,

the caulking recesses formed in the motor case side annular engaging portion are formed over the entire circumference of the circumferential surface of the motor case side annular engaging portion, or are formed at predetermined positions in the circumferential surface of the motor case side annular engaging portion in a dispersed manner.

4. Electric drive device according to claim 2 or 3,

the seal region portion is formed by filling the liquid sealant into a space formed in a state where the metal cover side annular engagement portion is engaged with the motor case side annular engagement portion.

5. The electromotive drive device according to claim 4,

an annular groove that recedes inward is formed on the peripheral surface of the motor case-side annular engaging portion on the side of the open end of the metal cover when viewed from the caulking recess, and the liquid sealant is filled in the annular groove.

6. The electromotive drive device according to claim 5,

and forming a bent portion by using at least two cut portions formed at the opening end of the metal cover, wherein the bent portion is bent to be engaged with the wall surface of the annular groove.

7. The electromotive drive device according to claim 6,

the caulking recesses are dispersedly formed at predetermined positions on the peripheral surface of the motor case-side annular engaging portion, and the bent portion formed at the opening end of the metal cover is formed at a position corresponding to the caulking recesses.

8. The electric drive of claim 1,

the fixing region portion is formed by press-fitting or shrink-fitting the motor case side annular engaging portion and the metal cover side annular engaging portion.

9. The electromotive drive device according to claim 8,

a housing groove for housing the opening end of the metal cover is formed in the motor case side annular engagement portion, the opening end of the metal cover is housed in the housing groove, and the housing groove is filled with the liquid sealant so as to surround the opening end from the outside.

10. An electric power steering device is characterized by comprising: 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 torque of the steering shaft; an aluminum-based metal motor case that houses the electric motor; an electronic control unit disposed on one side of an end surface portion of the motor case on the opposite side of an output portion of the rotary shaft of the electric motor, and including a control circuit unit for driving the electric motor, a power supply circuit unit, and a power conversion circuit unit; a metal cover covering the electronic control unit;

the electric power steering device is provided with: a motor case side annular engaging portion formed on an outer peripheral surface of an end surface portion of the motor case on a side opposite to an output portion of a rotating shaft of the electric motor; a metal cover side annular engaging portion formed at an opening end of the metal cover and engaged with the motor case side annular engaging portion;

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

12. The electric power steering apparatus according to claim 11,

13. The electric power steering apparatus according to claim 11 or 12,

14. The electric power steering apparatus according to claim 13,

15. The electric power steering apparatus according to claim 14,

and forming a bent portion by using at least two cut portions formed at the opening end of the metal cover, wherein the bent portion is bent to be engaged with the wall surface of the annular groove.

16. The electric power steering apparatus according to claim 15,

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

the fixing region portion is formed by press-fitting or shrink-fitting the motor case side annular engaging portion and the metal cover side annular engaging portion.

18. The electric power steering apparatus according to claim 17,

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 machines, it has been common practice to drive machine system control elements using an electric motor, but recently, a so-called electromechanical integrated electric drive device has been employed in which an electronic control unit including a semiconductor element or the like for controlling the rotation speed and 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 steering direction and a torque of a steering shaft that is turned by a driver operating 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 values, thereby generating a steering assist torque. In order to control the electric motor, an Electronic Control Unit (ECU) is provided in the power steering system.

As a conventional electric power steering apparatus, for example, an electric power steering apparatus described in japanese patent application laid-open No. 2015-134598 (patent document 1) is known. Patent document 1 describes an electric power steering apparatus 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 a substrate on which electronic components of the electronic control unit are mounted is mounted on a heat sink that is disposed on the side of the motor case opposite to the output shaft in the axial direction and functions as an ECU case.

The substrate mounted on the heat sink includes a power supply circuit unit, a power conversion circuit unit, and a control circuit unit, the power conversion circuit unit includes a power switching element such as a MOSFET or an IGBT that drives and controls the electric motor, the control circuit unit controls 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.

Then, electric 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 such as an operation state is supplied from a detection sensor or the like to the electronic control unit. The connector housing functions as a cover body, and is fixed so as to hermetically seal the heat sink, and the connector housing is fixed to the outer peripheral surface of the heat sink by fixing screws.

Note that, in addition to this, as an electric drive device in which an electronic control device is integrated, an electric brake, an electric hydraulic controller for various hydraulic control, and the like are known, but in the following description, a description will be given by taking an electric power steering device as a representative example.

Disclosure of Invention

Technical problem to be solved by the invention

In the electric power steering apparatus having the structure described in 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 on the outer peripheral side.

Further, a sealing member such as an O-ring is used for liquid tightness between the motor case and the heat sink or between the heat sink and the connector case. The fixing between the motor case and the heat sink or the fixing between the heat sink and the connector housing is performed by fixing screws. Note that, in the case where a heat sink is not used, an O-ring is interposed between the motor housing and the connector housing and fixed by a fixing screw.

However, in automobiles, the sealing structure is often used in areas with severe salt damage, and in the case of a liquid-tight sealing structure using only O-rings, a region where the O-rings are arranged substantially forms a fitting gap. Therefore, the saline water enters the fitting gap, corrodes the O-ring housing, and in the worst case, causes poor liquid-tightness, and the saline water enters the inside, thereby impairing the electrical reliability.

Further, if the fixing portion and the fixing screw are provided on the outer peripheries of the motor case, the heat sink, and the connector housing, there is a possibility that the fixing strength is lowered due to corrosion of the fixing screw, and the mechanical reliability is impaired, and there is a problem that the external appearance shape is increased and the weight is increased.

Therefore, an electric drive device and an electric power steering device that solve these problems are required.

In addition, although a secondary problem is involved, in the electric power steering apparatus having the configuration described in patent document 1, a radiator member for radiating heat of the power supply circuit portion and the power conversion circuit portion to the outside is disposed between the motor case and the ECU case. Therefore, the axial length tends to be excessively increased in accordance with the radiator module. Further, the amount of heat generated by the electric devices constituting the power supply circuit portion and the power conversion circuit portion increases, and in the case of downsizing, it is necessary to efficiently dissipate the heat to the outside. Therefore, it is also required to reduce the axial length as much as possible and to effectively dissipate heat of the power supply circuit portion and the power conversion circuit portion to the outside.

The main object of the present invention is to provide a novel electric drive device and electric power steering device that have improved mechanical and electrical reliability and a reduced weight by reducing the external shape.

Means for solving the problems

The present invention is characterized by comprising: a motor case side annular engaging portion formed on an outer peripheral surface of an end surface portion of the metal motor case on a side opposite to an output portion of the rotating shaft of the electric motor; a metal cover side annular engaging portion formed at an opening end of a metal cover covering an electronic control portion for controlling the electric motor, and engaged with the motor case side annular engaging portion; the metal cover side annular engaging portion and the annular engaging portion are fixed by a fixing means without using a fixing screw in a state where the metal cover side annular engaging portion is engaged with the motor housing side annular engaging portion, thereby forming a fixed region portion, and a seal region portion filled with a liquid sealant is formed between the fixed region portion and an opening end of the metal cover.

Effects of the invention

According to the present invention, since the sealing region portion filled with the liquid sealant is formed between the fixing region portion and the opening end of the metal cover, it is possible to suppress intrusion of saline water or the like into the fixing region portion, thereby improving mechanical and electrical reliability. In addition, since the fixing screw is not used, the external appearance can be reduced and the weight can be reduced.

Drawings

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

Fig. 2 is an overall perspective view showing the overall shape of the electric power steering apparatus according to the embodiment of the present invention, before being fixed by an adhesive tape.

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

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

Fig. 5 is a sectional view of the motor housing shown in fig. 4 cut in the axial direction.

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

Fig. 7 is a perspective view showing a state in which the power circuit unit is mounted and fixed on the motor case shown in fig. 6.

Fig. 8 is a perspective view showing a state in which the control circuit unit is mounted and fixed on the motor case shown in fig. 7.

Fig. 9 is a perspective view showing a state in which the connector terminal assembly shown in fig. 8 is mounted and fixed on the motor housing.

Fig. 10 is a front view of the electric power steering apparatus after caulking and fixing according to the first embodiment of the present invention.

Fig. 11 is a cross-sectional view of the electric power steering apparatus shown in fig. 10, which is a cross-sectional view after being caulked and fixed.

Fig. 12 is a partially enlarged cross-sectional view showing an axial cross section of the motor case and the metal cover after caulking and fixing the motor case and the metal cover in the vicinity of the engaging portion.

Fig. 13 is an enlarged sectional view of the portion P of fig. 12.

Fig. 14 is a plan view as viewed from the connector terminal assembly side of fig. 12.

Fig. 15 is an enlarged sectional perspective view of the second embodiment of the present invention after caulking.

Fig. 16 is an enlarged cross-sectional view of fig. 5 after caulking.

Fig. 17 is an enlarged sectional perspective view of the third embodiment of the present invention after being subjected to shrink fitting.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the embodiments described below, and various modifications and application examples are included in the technical concept of the present invention.

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

First, a steering device for steering 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 meshes with a rack, not shown, extending in the left-right direction of the vehicle body. Tie rods 3 for steering the front wheels in the right and left directions are connected to both ends of the rack, and the rack is covered with a rack case 4. A rubber boot 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 torque of the steering shaft 2 is provided, 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 on the side opposite to the output shaft of the electric motor portion 8.

In the electric power steering apparatus 6, if the steering shaft 2 is operated to turn in either direction by operating the steering wheel, the torque sensor 7 detects the turning direction and the torque of the steering shaft 2, and based on the detected values, the control circuit section calculates the driving operation amount of the electric motor. Based on the calculated driving 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 rotates to drive the steering shaft 1 in 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 automobile is operated. Since these structures and functions are already known, further description thereof will be omitted.

As described above, in the electric power steering system having the structure described in patent document 1, the electric power steering system is often used in a region with a serious salt damage, and in the case of a liquid-tight seal structure using only O-rings, a fitting gap is substantially formed in a region where the O-rings are arranged. Therefore, the saline water enters the fitting gap, corrodes the O-ring housing, and in the worst case, may cause poor liquid-tightness, and the saline water may infiltrate into the inside to impair electrical reliability.

Against this background, the present invention proposes an electric power steering apparatus having the following configuration.

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Electric drive device and electric power steering device

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