JP5279695B2 - Power steering device - Google Patents

Description

  The present invention relates to a power steering apparatus.

  As this type of technology, the technology described in Patent Document 1 below is disclosed. This publication discloses an electric power steering device in which a control device is provided between the electric motor and the speed reducer. In this electric power steering apparatus, inside the control housing in which the control device is accommodated, the partition member accommodates the motor housing in which the electric motor is accommodated, the gear housing in which the speed reducer is accommodated, and the control device. The space is divided.

JP 2009-46045 A

Since the control device is vulnerable to water and dust, the housing in which the control device is housed is required to be waterproof and dustproof, and the air in the housing repeatedly expands and contracts due to heat generated by the control device. It was necessary to secure breathability by installing a breathing hole that absorbs the volume change of air.
The present invention has been made paying attention to the above problems, and the object of the present invention is to ensure both waterproofness and dustproofness and air permeability in the housing in which the control device is accommodated. It is to provide a power steering device that can be used.

  In order to achieve the above object, according to the present invention, when the axial direction of the output shaft is defined as the axial direction, the control housing is provided at one axial end of the control housing so as to surround at least a part of the outer periphery of the output shaft or the rotating shaft. And a first through hole that is provided at one end in the axial direction of the control housing and that is disposed radially outside the surrounding portion, and passes through the inside and the outside of the control housing, and the shaft of the control housing A waterproof wall provided at one end portion in the direction, disposed radially outside the surrounding portion and the first through hole, and provided to surround the surrounding portion and the first through hole; And the direction of the opening inside the waterproof wall is the opening and the outer edge of the first through hole, with the center axis being outside the predetermined angle range including the virtual line connecting the center axis and the first through hole Open to the outside of a pair of tangents that touch And a second through hole passing through the inside and outside of the waterproof wall, the provided.

  Since the first through hole, the output shaft of the electric motor, and the rotary shaft of the reversible pump are defined by the surrounding portion, it is possible to prevent foreign matter from entering the control housing from the output shaft or the rotary shaft side. it can.

It is a block diagram of the power steering apparatus of Example 1. It is a perspective view of the electromechanical integrated unit of Example 1. It is sectional drawing of the electromechanical integrated unit of Example 1. FIG. It is a fragmentary sectional view near the breathing hole of the electromechanical integrated unit of the first embodiment. It is the side view and sectional drawing of the control housing of Example 1, and a motor housing. It is an enlarged view of the respiratory hole and respiratory valve of Example 1. It is the figure which looked at the pump body of Example 1 from the external side surface.

[Example 1]
[Configuration of power steering device]
FIG. 1 is a configuration diagram of the power steering device 24. The power steering device 24 is a steering mechanism 3 that transmits a steering force to the steered wheels 2 by a driver, and a steering shaft 25 to which the steering force is input from the steering wheel 1 and a steering force in the rotational direction of the steering shaft 25 are A rack and pinion 26 that converts the steering force in the direction and a tie rod 27 that transmits the steering force to the steered wheels 2 are provided.
Further, as a mechanism for assisting the driver's steering force, a torque sensor 28 for detecting torque applied to the steering shaft 25 and an electric motor 5 for driving the reversible pump 7 based on information from the torque sensor 28 are provided. An electronic control unit 10 (control circuit) for controlling, and a hydraulic circuit 29 for supplying the discharge pressure of the reversible pump 7 to the hydraulic power cylinder 32 are provided.
The rack and pinion 26 includes a pinion 30 that rotates integrally with the steering shaft 25 and a rack shaft 31 that meshes with the pinion. Both ends of the rack shaft 31 are connected to the tie rod 27, and the axial movement of the rack shaft 31 is transmitted to the steered wheels 2.
Inside the hydraulic power cylinder 32, there is provided a piston 33 that can move in the axial direction within the hydraulic power cylinder 32. The piston 33 defines a first hydraulic chamber 34 and a second hydraulic chamber 35 within the hydraulic power cylinder 32. It is installed. The hydraulic power cylinder 32 is fixed to the rack shaft 31.
The hydraulic circuit 29 includes a first passage 36 connected to the reversible pump 7 (decelerator) and the first hydraulic chamber 34, and a second passage 37 connected to the reversible pump 7 and the second hydraulic chamber 35. .
The electronic control unit 10 inputs steering torque information from the torque sensor 28, and calculates assist torque according to the steering torque information. The reversible pump 7 is driven by controlling the electric motor 5 so as to apply the calculated assist torque to the steering mechanism 3. The oil supplied by the reversible pump 7 causes the hydraulic pressure to act on the first hydraulic chamber 34 and the second hydraulic chamber 35 of the hydraulic power cylinder 32, and assist force is applied to the rack shaft 31.

[Structure of electro-mechanical unit]
FIG. 2 is a perspective view of the electromechanical integrated unit 16. FIG. 3 is a cross-sectional view of the electromechanical integrated unit 16. FIG. 4 is a partial sectional view of the vicinity of the breathing hole 12 of the electromechanical integrated unit 16. FIG. 5 is a side view (FIG. 5A) and a cross-sectional view (FIG. 5B) of the control housing 9 and the motor housing 82 of the electromechanical integrated unit 16. FIG. 6 is an enlarged view of the breathing hole 12 and the breathing valve 19. FIG. 7 is a view of the pump housing body 44 as seen from the outer side surface.
The electromechanical unit 16 includes an electronic control unit 10 housed in the control housing 9, an electric motor 5 housed in the motor housing 82, a reversible pump 7 housed in the pump housing 38, and a reversible pump 7. It is comprised from the reservoir tank 39 which supplies.
The control housing 9 is formed of a control housing body 40 and a control housing cover 41. The motor housing 82 is formed from the motor housing body 42 and the motor housing cover 43. The pump housing 38 is formed by a pump housing body 44 and a pump housing cover 45.

(Configuration of electronic control unit)
The electronic control unit 10 is accommodated in an accommodating portion 72 that is formed hollow by the control housing body 40, the control housing cover 41, and the defining member 46 described later. The electronic control unit 10 is fixed to the control housing body 40. The electronic control unit 10 is connected to a stator 48 and a resolver 49 of the electric motor 5 described later via a bus bar. The electronic control unit 10 is connected to the connector 50 from the outside of the control housing body 40, and the steering torque information from the torque sensor 28 is input via the connector 50.
(Configuration of electric motor)
The electric motor 5 is accommodated in an accommodating portion 47 formed hollow by the motor housing body 42 and the motor housing cover 43. The electric motor 5 includes a hollow stator 48, a rotor 51 that rotates integrally with the output shaft 4, and a resolver 49 that detects the rotational position of the rotor 51.
The stator 48 is fixed to the motor housing body 42. The rotor 51 is inserted into the hollow portion of the stator 48. The output shaft 4 passes through the housing portion 72 of the control housing 9 and the housing portion 47 of the motor housing 82 and projects outside from the through hole 8 formed in the control housing cover 41. An defining member 46 having a hollow penetrating portion 52 is provided on the outer periphery of the range where the output shaft 4 penetrates the accommodating portion 72 of the control housing 9. The defining member 46 is inserted into the through hole 8 of the control housing 9, and an outer end of the control housing 9 is formed with a projecting portion 78 projecting outward from the opening of the through hole 8.
The output shaft 4 is accommodated in a ball bearing 54 accommodated in a bearing accommodating portion 53 formed on the bottom of the motor housing cover 43 and a bearing accommodating portion 55 provided in an opening of the defining member 46 on the motor housing cover 43 side. The ball bearing 56 is supported by a shaft. Further, a resolver accommodating portion 57 is formed on the opening end side of the defining member 46 further than the bearing accommodating portion 55, and a resolver 49 is accommodated therein.
Further, a seal member 79 is inserted into a seal housing portion 73 provided in the opening on the outside of the defining member 46. The seal member 79 slides on the outer peripheral surface of the output shaft 4 to ensure a sealing property between the housing portion 47 of the motor housing 82 and the outside.

(Configuration of reversible pump)
The reversible pump 7 is accommodated in an accommodating portion 74 formed hollow by a pump housing body 44 and a pump housing cover 45. The reversible pump 7 includes an inscribed pump gear 58 and a side plate 59 that abuts against a side surface of the pump gear 58. The pump gear 58 includes an internal gear 60 fixed to the pump housing body 44 and an external gear 61 that rotates integrally with the rotary shaft 6. The reversible pump 7 is driven by the electric motor 5, and oil is supplied from the first hydraulic chamber 34 to the second hydraulic chamber 35 and from the second hydraulic chamber 35 to the first hydraulic chamber 34 according to the rotation direction of the electric motor 5. It is possible to absorb and discharge in both directions.
The rotary shaft 6 includes an oil seal 65 housed in a seal housing portion 62 formed on the side plate 59 and an oil seal housed in a seal housing portion 64 formed in a through hole 63 that penetrates the pump housing body 44. And 65. The rotating shaft 6 protrudes outside through the through hole 63 of the pump housing body 44. The rotary shaft 6 is connected to the output shaft 4 via a connector 80, and transmits the rotational drive of the electric motor 5 to the reversible pump 7.
A seal member 67 is inserted into a seal housing portion 66 provided in an opening on the outside of the pump housing body 44. The seal member 67 slides on the outer peripheral surface of the rotary shaft 6 and ensures a sealing property between the housing portion 74 of the pump housing 38 and the outside.
The reversible pump 7 has a function as a speed reducer that reduces the rotational speed of the electric motor 5 and increases the rotational torque to transmit work to the steering mechanism 3.

(Structure of reservoir tank)
The reservoir tank 39 includes a tank body 68 formed integrally with the pump housing cover 45, a tank cover 69, and a lid member 70 that closes the opening of the tank body 68. The reservoir tank 39 stores the oil in the oil storage portion 71 formed by the tank body 68 and the tank cover 69.
(Composition of breathing hole)
The control housing cover 41 of the control housing 9 is formed with a breathing hole 12 (first through hole) that allows the accommodating portion 72 to communicate with the outside, and a breathing valve 19 is attached to the breathing hole 12. The breathing valve 19 includes a bottom 75 that is inserted into the breathing hole 12, a filter 76 that is stretched on the opening of the bottom 75, and a cap 77 that is attached to the bottom 75 and covers the filter 76.
The bottom 75 is inserted into the breathing hole 12 with an O-ring 81 attached to the outer periphery. The filter 76 is a cloth having air permeability for allowing air and water vapor to pass therethrough and waterproofing for blocking water. The cap 77 is provided so that water or mud or the like does not directly contact the filter 76, and has an opening so that air and water vapor can be sufficiently transferred between the filter 76 and the outside. ing.
The breathing valve 19 is formed between the side surface of the control housing cover 41 of the control housing 9 and the side surface of the pump housing body 44 of the pump housing 38, and is accommodated in a waterproof wall 13 described later.

(Configuration of the pump body side)
As shown in FIG. 7, the surrounding portion 11 is formed on the side surface of the pump housing body 44 on the control housing 9 side and outside the opening portion of the through hole 63 in the radial direction. The surrounding portion 11 is formed so as to surround a part of the outer periphery of the output shaft 4 of the electric motor 5 and the rotating shaft 6 of the reversible pump 7. In the surrounding portion 11, a seal check hole 23 (third through hole) that penetrates the inside and outside of the surrounding portion 11 is formed. The seal check hole 23 is provided with a seal member 67 for checking. When the seal member 67 is not properly mounted, oil leaks from the seal check hole 23. The breathing hole 12 formed in the control housing cover 41 of the control housing 9 is formed on the radially outer side of the surrounding portion 11.
On the control housing 9 side surface of the pump housing body 44 and on the radially outer side of the surrounding portion 11 and the breathing hole 12, a waterproof wall 13 provided so as to surround the surrounding portion 11 and the breathing hole 12 is formed. Yes. The waterproof wall 13 is formed with a discharge hole 15 (second through hole) that drains oil and water from a region surrounded by the waterproof wall 13. An extending wall 20 is connected to the inner end of the waterproof wall 13 of the discharge hole 15.
The axial direction of the discharge hole 15 and the extending wall 20 is formed toward the direction of gravity. Further, the opening 14 inside the waterproof wall 13 of the discharge hole 15 and the opening 22 inside the waterproof wall 13 of the extending wall 20 are opened upward in the gravitational direction toward the surrounding portion 11. An opening 21 on the outside of the waterproof wall 13 of the discharge hole 15 is open downward in the direction of gravity. Further, the inner end portion of the waterproof wall 13 of the extending wall 20 is disposed below the breathing hole 12 in the gravity direction.
The discharge hole 15 is not limited to this configuration, and water that has entered from the outside through the discharge hole 15 may be prevented from going to the breathing hole 12. Specifically, the discharge hole 15 may be formed under the following conditions. When the axis of the rotary shaft 6 is the central axis 17, the discharge hole 15 is disposed outside a predetermined angle range A including a virtual line connecting the central axis 17 and the axis 18 of the breathing hole 12, and the waterproof wall 13 It is only necessary to satisfy the condition that the direction of the inner opening 14 is directed toward the outside of a pair of tangents that contact the outer edge of the opening 14 and the breathing hole 12.
The side surface on the control housing 9 side of the pump housing body 44 corresponds to one axial end portion of the output shaft 4 of the control housing 9. That is, the surrounding portion 11 and the waterproof wall 13 are provided at one axial end portion of the output shaft 4 of the control housing 9.

[Action]
Next, the operation of the power steering device 24 according to the first embodiment will be described. In the electromechanical integrated unit 16, the electronic control unit 10 is incorporated in the unit in which the electric motor 5 and the reversible pump 7 are integrated. However, since the electronic control unit 10 is vulnerable to water and dust, the housing portion 72 that houses the electronic control unit 10 is required to be dustproof and waterproof. On the other hand, since the electronic control unit 10 generates heat, the air in the accommodating portion 72 expands and contracts, and it is necessary to provide a breathing hole 12 that absorbs the volume change of the air to ensure air permeability. In order to secure the dustproof and waterproof properties of the breathing hole 12, it is conceivable to provide a wall around the breathing hole 12. However, the control housing cover 41 is manufactured by aluminum die casting, and the control housing cover 41 has a main body. Since it is necessary to form a thin wall with respect to the thickness, the flow of aluminum is poor and it is difficult to form the wall.
Therefore, in the power steering device 24 of the first embodiment, the surrounding portion 11 is formed on the side surface of the pump housing body 44 of the pump housing 38 adjacent to the control housing cover 41 of the control housing 9. The surrounding portion 11 surrounds the outer periphery of the output shaft 4 of the electric motor 5 exposed outside the motor housing 82 and the rotating shaft 6 of the reversible pump 7 exposed outside the pump housing 38. Further, a waterproof wall 13 is formed on the side surface of the pump housing body 44 so as to surround the surrounding portion 11 and the breathing hole 12, and the waterproof wall 13 is opened toward the surrounding portion 11, so that the inside and outside of the waterproof wall are formed. And a discharge hole 15 penetrating them.
Therefore, the breathing hole 12, the output shaft 4 of the electric motor 5, and the rotating shaft 6 of the reversible pump 7 are defined by the surrounding portion 11, so that foreign matter from the output shaft 4 and the rotating shaft 6 side is caused in the control housing 9. It can suppress entering into.
In addition, since the breathing hole 12 is surrounded by the waterproof wall 13, it is possible to prevent foreign matter from entering the control housing 9.
Further, since the discharge hole 15 is formed so as to open toward the surrounding portion 11, it is possible to prevent foreign matter from entering the control housing.

[effect]
The effects of the power steering device 24 of the first embodiment will be described below.
An electric motor which is provided between the steering wheel 1 and the steered wheel 2 and has a steering mechanism 3 for transmitting the steering operation of the steering wheel 1 to the steered wheel 2 and an output shaft 4 and applies a steering assist force to the steering mechanism 3. A reversible shaft 6 is provided between the motor 5, the steering mechanism 3, and the electric motor 5, has a rotating shaft 6 connected to the output shaft 4 of the electric motor 5, and transmits the rotational force of the electric motor 5 to the steering mechanism 3. A control housing 9 provided between the electric pump 7 and the electric motor 5 and the reversible pump 7 and having a through hole 8 through which the output shaft 4 or the rotary shaft 6 passes, and accommodated in the control housing 9, 5 is provided on the one end side of the axial direction of the control housing 9 when the rotation axis direction of the output shaft 4 is the axial direction, and the outer circumference of the output shaft 4 or the rotation shaft 6 at least The surrounding part 11 formed so as to surround the part and the breathing that is provided at one end in the axial direction of the control housing 9 and that is disposed radially outside the surrounding part 11 and penetrates the inside and the outside of the control housing 9 A waterproof wall provided on the one end side in the axial direction of the hole 12 and the control housing 9, disposed on the radially outer side of the surrounding portion 11 and the breathing hole 12, and so as to surround the surrounding portion 11 and the breathing hole 12 13 and the waterproof wall 13, and when the output shaft 4 is the central axis 17, it is disposed outside a predetermined angle range including a virtual line connecting the central axis 17 and the axis 18 of the breathing hole 12. 13 is provided with a discharge hole 15 that opens toward the outside of a pair of tangents that contact the opening 14 and the outer edge of the breathing hole 12, and penetrates the inside and outside of the waterproof wall 13. .
Therefore, the breathing hole 12, the output shaft 4 of the electric motor 5, and the rotating shaft 6 of the reversible pump 7 are defined by the surrounding portion 11, so that foreign matter from the output shaft 4 and the rotating shaft 6 side is caused in the control housing 9. It can suppress entering into.
In addition, since the breathing hole 12 is surrounded by the waterproof wall 13, it is possible to prevent foreign matter from entering the control housing 9.
Further, since the discharge hole 15 is formed so as to open toward the surrounding portion 11, it is possible to prevent foreign matter from entering the control housing.

[Other Examples]
As described above, the present invention has been described based on the first embodiment. However, the specific configuration of each invention is not limited to each embodiment, and even if there is a design change or the like without departing from the gist of the invention. Are included in the present invention.
For example, in the power steering device 24 of the first embodiment, the surrounding portion 11 and the waterproof wall 13 are provided on the side surface of the pump housing body 44 on the control housing 9 side. In this configuration, the surrounding portion 11 and the waterproof wall 13 may be provided at one axial end portion of the output shaft 4 of the control housing 9, that is, on the pump housing 38 side of the control housing cover 41.
Further, for example, in the power steering device 24 of the first embodiment, the reversible pump 7 is used as a speed reducer, but a speed reducer such as a worm gear may be used.

Further, technical ideas other than the claims that can be grasped from the above embodiments will be described below together with the effects thereof.
(A) In the power steering apparatus according to claim 1,
The power steering apparatus according to claim 1, wherein the predetermined angle range is a range sandwiched between a pair of tangent lines that pass through the central axis and contact an outer edge of the first through hole.
Therefore, since the first through hole and the second through hole do not overlap in the circumferential direction, it is possible to prevent foreign matter that has passed through the second through hole from entering the control housing from the first through hole. it can.
(B) In the power steering device according to claim 1,
The power steering apparatus further comprising a filter provided in the first through hole, closing the first through hole, and made of a material having air permeability and not water permeability.
The filter can ensure water permeability and dust resistance while ensuring air permeability. Moreover, damage to the filter can be prevented by the waterproof wall.
(C) In the power steering device according to claim 1,
The power steering device according to claim 1, further comprising an extending wall provided on a radially inner side of the second through hole, having one end connected to the second through hole and the other end opened to the inside of the waterproof wall.
Therefore, the invasion of foreign matter from the outside to the inside of the waterproof wall can be suppressed.
(D) In the power steering device described in (c) above,
The second through hole is disposed so as to open downward in the gravitational direction when the power steering device is mounted on a vehicle.
The power steering device, wherein the other end side of the extending wall is arranged so as to open toward the upper side in the gravity direction.
Therefore, if the foreign matter inside the waterproof wall, particularly oil leaking from the pump housing or the control housing side, is less than a predetermined amount, it can be prevented from being discharged to the outside by the extending wall.
(E) In the power steering apparatus described in (d) above,
A third through hole provided in the surrounding portion and penetrating the inside and the outside of the surrounding portion;
The power steering device, wherein the third through hole is disposed to open downward in the direction of gravity when the power steering device is mounted on a vehicle.
Therefore, the oil leaked from the output shaft of the electric motor and the rotary shaft of the reversible pump passes through the third through hole and is stored inside the waterproof wall. When the amount of oil stored inside the waterproof wall exceeds the waterproof wall, the oil is discharged to the outside through the second through hole, so that the sealability of the rotating shaft and the output shaft can be confirmed.
(F) In the power steering device described in (e) above,
The extended wall is formed such that the other end of the extended wall is disposed below the first through hole in the gravitational direction when the power steering device is mounted on a vehicle. Steering device.
Therefore, when the amount of foreign matter stored in the waterproof wall exceeds the waterproof wall, the foreign matter is discharged from the second through hole, so that the foreign matter is prevented from entering the control housing through the first through hole. be able to.

1 Steering wheel 2 Steering wheel 3 Steering mechanism 4 Output shaft 5 Electric motor 6 Rotating shaft 7 Reversible pump (decelerator)
8 Through-hole 9 Control housing 10 Electronic control unit (control circuit)
11 Enclosure 12 Breathing hole (first through passage)
13 Waterproof wall 15 Discharge hole (second through hole)
16 Mechanical-electric unit 17 Central axis 18 Axis 19 Breathing valve 20 Extension wall 23 Seal check hole (third through hole)
24 Power steering device 38 Pump housing 76 Filter 82 Motor housing

Claims (1)

A steering mechanism provided between a steering wheel and a steered wheel, and transmitting a steering operation of the steering wheel to the steered wheel;
An electric motor having an output shaft and applying a steering assist force to the steering mechanism;
A speed reducer provided between the steering mechanism and the electric motor, having a rotating shaft connected to an output shaft of the electric motor, and transmitting a rotational force of the electric motor to the steering mechanism;
A control housing provided between the electric motor and the speed reducer and having a through hole through which the output shaft or the rotation shaft passes;
A control circuit housed in the control housing and drivingly controlling the electric motor;
When the axial direction of the output shaft is defined as the axial direction, the control housing is provided on the one end side in the axial direction of the control housing, and is formed so as to surround at least a part of the outer periphery of the output shaft or the rotating shaft. An enclosure,
A first through hole provided at one end of the control housing in the axial direction and disposed radially outside the enclosure; and passing through the inside and the outside of the control housing;
A waterproof wall provided at the one axial end of the control housing, disposed radially outside the surrounding portion and the first through hole, and surrounding the surrounding portion and the first through hole. When,
Provided on the waterproof wall, when the output shaft is the central axis, the waterproof wall is disposed outside a predetermined angle range including a virtual line connecting the central axis and the first through hole, and an opening inside the waterproof wall A second through hole that opens toward the outside of a pair of tangents that contact the opening and the outer edge of the first through hole, and penetrates the inside and the outside of the waterproof wall;
A power steering apparatus comprising:

Images