JP2002249055A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a steering device for vehicle. SOLUTION: An active steering device 10 connects a first pinion shaft 24 connected to a steering wheel 21 and a first rack shaft 26 connected to front wheels 29 and 29 to each other via a first rack-and-pinion mechanism 25, and fits them to a housing 46. The housing 46 is movably fitted to a vehicle body 41 in the vehicle width direction, and a motor 71 for moving the housing 46 in the vehicle width direction is fitted to the vehicle body 41. The motor 71 is disposed so that a motor shaft 71a is substantially parallel to the first rack shaft 26. The motor shaft 71a is connected to a second rack 96 via a hypoid gear mechanism 73 and a second rack-and-pinion mechanism 75. A second rack shaft 76 is disposed substantially parallel to the first rack shaft 26, fitted movably in the vehicle width direction, and connected to the housing 46.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a vehicle steering system.

[0002]

2. Description of the Related Art In recent years, there has been developed a steering apparatus for a vehicle in which the steering stability and the kinetic performance of the vehicle are further improved in accordance with the running state and the steering state of the vehicle. As this type of steering device, for example, a so-called active steering device or a so-called active steering device capable of controlling a steering angle of a front wheel independently of a driver's steering operation, so that left and right front wheels and left and right rear wheels can be steered. The development of a four-wheel steering system is also progressing. As an active steering device, for example, Japanese Patent Application Laid-Open No. 7-52819 entitled "Auxiliary steering device for wheels" is known. Hereinafter, this conventional technique will be described.

The above prior art is disclosed in FIG. 1 and FIG.
As shown in FIG. 1, the steering gear box 1 is mounted on the vehicle body via left and right brackets 5 and 6 (the numbers are cited in the gazette; the same applies hereinafter). 1, a motor shaft of the motor 9 is connected via a non-reciprocal transmission 12. The steering gear box 1 is a storage member which is elongated in the vehicle width direction and stores a stub shaft 2 having a pinion 3 connected to a steering wheel 21 and a rack 4 which meshes with the pinion 3 and is connected to the front wheels 22. The irreversible transmission 12 is a worm gear mechanism including a worm 10 connected to a motor shaft and a worm gear 11 formed on the steering gear box 1.

Such an active steering device can steer the front wheels 22 via the rack 4 by steering the steering wheel 21. Moreover, the front wheels 22 can be steered by moving the rack 4 in the vehicle width direction by moving the steering gear box 1 in the vehicle width direction by the motor 9. The driver's steering operation can be assisted by the motor 9.

[0005]

In the above-mentioned conventional technique, the driving torque of the motor 9 is transmitted to the steering gear box 1 via a worm gear mechanism. Inevitably, the motor 9 is arranged so that the motor axis is orthogonal to the steering gear box 1 which is elongated in the vehicle width direction. Generally, the length of the motor 9 in the motor axis direction is larger than the width. Accordingly, the motor 9 protrudes greatly from the side wall of the elongated steering gear box 1. As a result, the steering device must be large. When a steering device is arranged in a narrow space such as in an engine room of a vehicle or under a floor, the arrangement of the steering device is difficult because the steering device is large.

An object of the present invention is to provide a technique capable of reducing the size of a steering device.

[0007]

To achieve the above object, a first pinion shaft connected to a steering wheel and having a first pinion is rotatably mounted on a housing and meshes with the first pinion. An electric motor having a rack and a first rack shaft connected to a steering wheel is mounted on a housing movably in a vehicle width direction, the housing is mounted on a vehicle body movably in the vehicle width direction, and an electric motor for moving the housing in the vehicle width direction. In a steering device mounted on a vehicle body and capable of steering a steered wheel also by moving a housing in a vehicle width direction with an electric motor, the electric motor is arranged such that an electric motor axis is parallel or substantially parallel to a first rack axis. Arranged, and the motor shaft is connected to the second pinion shaft via a hypoid gear mechanism or a worm gear mechanism,
The pinion of the second pinion shaft is engaged with the rack of the second rack shaft, and the second rack shaft is mounted on the vehicle body so as to be movable in the vehicle width direction. The second rack shaft is parallel or substantially parallel to the first rack shaft. And connected to the housing.

[0008] Since the second pinion shaft is connected to the motor shaft of the motor that generates the housing drive torque via a hypoid gear mechanism or a worm gear mechanism, the second pinion shaft extends in a direction orthogonal to the motor shaft. Since the second rack shaft is connected to the second pinion shaft via a rack and pinion mechanism, the second rack shaft extends in a direction orthogonal to the second pinion shaft. Therefore, the motor can be arranged such that the motor axis is parallel or substantially parallel to the second rack axis. On the other hand, when the first rack shaft connected to the steered wheels is housed in the housing and the second rack shaft is connected to the housing, the second rack shaft can be arranged parallel or substantially parallel to the first rack shaft. . Therefore, the motor can be arranged such that the motor axis is parallel or substantially parallel to the first rack axis.

The projecting distance of the second rack shaft and the electric motor projecting in the radial direction of the first rack shaft can be reduced. As a result, the steering device becomes smaller. Since the small steering device is arranged in a narrow space such as in the engine room of the vehicle or under the floor, the degree of freedom in designing the vehicle is increased.

According to another aspect of the present invention, there is provided a steering apparatus for steering left and right front wheels and left and right rear wheels.
By moving the rack shaft extending in the vehicle width direction and connected to the rear wheels in the vehicle width direction with an electric motor mounted on the vehicle body, the rear wheel is steered. Arrange the motor so that it is almost parallel,
A pinion shaft is connected to the motor shaft via a hypoid gear mechanism or a worm gear mechanism, and a rack shaft is connected to the pinion shaft via a rack and pinion mechanism.

In the four-wheel steering system, since the pinion shaft is connected to the motor shaft of the motor that generates the rear wheel driving torque via a hypoid gear mechanism or a worm gear mechanism, the pinion shaft extends in a direction perpendicular to the motor shaft. Since the rack shaft is connected to the pinion shaft via a rack and pinion mechanism, the rack shaft connected to the rear wheel extends in a direction perpendicular to the pinion shaft. Therefore, the motor can be arranged such that the motor axis is parallel or substantially parallel to the rack axis. In this way, the projecting distance of the electric motor projecting in the radial direction of the rack shaft can be reduced.
As a result, the steering device becomes smaller. Since the small steering device is arranged in a narrow space such as under the floor of the vehicle, the degree of freedom in designing the vehicle is increased.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that "before", "after",
“Left”, “right”, “up”, and “down” follow directions seen from the driver. Also, the drawings should be viewed in the direction of reference numerals.

First, a steering apparatus according to a first embodiment will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a schematic diagram of a steering device (first embodiment) according to the present invention. The steering apparatus 10 according to the first embodiment controls the steering system 20 from the steering wheel 21 of the vehicle to the steered wheels (front wheels) 29, 29 and the steering angle of the steered wheels 29, 29 independently of the steering operation of the driver. An active steering device including an auxiliary steering mechanism 60 that can be controlled.

In the steering system 20, a first pinion shaft 24 is connected to a steering wheel 21 via a steering shaft 22 and a universal joint mechanism 23, and a first pinion shaft 24 is connected to a first pinion shaft 24 via a first rack and pinion mechanism 25. The first rack shaft 26 is connected, and the left and right steering wheels 29, 29 are connected to the first rack shaft 26 via left and right tie rods 27, 27 and knuckles 28, 28. The first rack and pinion mechanism 25 includes a first pinion shaft 2
The first pinion 31 provided on the first rack 4 and the first rack 32 provided on the first rack shaft 26 are engaged with each other.

In such a steering system 20, a first pinion shaft 24 extending in the vertical direction and a first rack shaft 26 extending in the vehicle width direction are housed in a housing 46. That is, the housing 46 has the first pinion shaft 24 mounted rotatably and immovably in the axial direction, and the first rack shaft 26 mounted so as to be movable in the vehicle width direction (axial direction). The storage member is concentric with the one rack shaft 26 and is elongated in the vehicle width direction.

The universal shaft coupling mechanism 23 includes a first rack shaft 26
Is allowed to displace the first pinion 31 in the axial direction. In other words, the universal joint mechanism 23 is a mechanism that transmits the steering torque of the steering wheel 21 to the first pinion shaft 24 and that can expand and contract in the axial direction of the first pinion shaft 24.

Here, the support structure of the housing 46 will be described. The support structure is such that the sub-frame 42 is attached to the vehicle body 41 by bolting, and three sub-frames (first, second, and third bearings) are mounted on the sub-frame 42. The housing 46 is attached to the vehicle body 41 so as to be movable in the vehicle width direction and non-rotatably by supporting the housing 46 so as to be movable in the vehicle width direction and non-rotatable through the portions 43 to 45).

The first bearing portion 43 is a slide bearing that is disposed concentrically with the housing 46 and attached to the sub-frame 42, and slidably supports the outer peripheral surface at one end of the housing 46 via a sliding bush 51. Things. The second bearing portion 44 and the third bearing portion 45 are slide bearings arranged at positions offset from the center of the housing 46 and attached to the subframe 42. Specifically, the second bearing portion 44 and the third bearing portion 45 include a bearing arm 46a extending radially outward from the other end of the housing 46, a sliding bush 52 provided in a bearing hole of the bearing arm 46a, A support shaft 53 for slidably supporting the support arm 46a via a sliding bush 52; The support shaft 53 is a member attached to the subframe 42. In the figure, 54, 5
4 is a dust sealing boot surrounding the support shaft 53;
5 is a bearing, and 56 and 56 are dust seal boots.

The auxiliary steering mechanism 60 drives the electric motor 71 based on predetermined steering conditions set in advance by the control unit 61, so that the housing 46 is moved in the vehicle width direction by the electric motor 71. is there. The control unit 61 includes, for example, a steering angle sensor 62 for detecting a steering angle of the steering wheel 21 and a vehicle speed sensor 6 for detecting a traveling speed of the vehicle.
3. It has a function of controlling the driving of the electric motor 71 in accordance with each detection signal of the displacement amount detection sensor 64 for detecting the displacement amount of the housing 46.

More specifically, the auxiliary steering mechanism 6
0 denotes an electric motor 7 for moving the housing 46 in the vehicle width direction.
A second pinion shaft 74 is connected to the first output shaft 71a (motor shaft 71a) via a hypoid gear mechanism 73, and a second rack shaft 76 is connected to the second pinion shaft 74 via a second rack and pinion mechanism 75. , A housing 46 connected to a second rack shaft 76.

The auxiliary steering mechanism 60 has a second pinion shaft 74 extending in the vertical direction and a second pinion shaft 74 extending in the vehicle width direction.
The rack shaft 76 is housed in an auxiliary steering housing 81. The auxiliary steering housing 81 is mounted on the vehicle body 41 via the sub-frame 42.

FIG. 2 is a front view of an auxiliary steering mechanism (first embodiment) according to the present invention, and shows a cross section of a main part. The auxiliary steering housing 81 is a storage member that is disposed so as to be parallel to the first rack shaft 26 and is concentric with the second rack shaft 76 and elongated in the vehicle width direction. (In the axial direction).
As a result, the second rack shaft 76 is attached to the vehicle body 41 (see FIG. 1) so as to be movable in the vehicle width direction, and the second rack shaft 76 is arranged so as to be parallel to the first rack shaft 26.

The second rack shaft 76 has one end protruding from the auxiliary steering housing 81 and a rod 83 connected to the end thereof via a universal joint (ball joint) 82. A bifurcated connecting arm 46 b extending in the direction is connected by a pin 84.
In the figure, 85 and 85 are bearings, and 86 and 87 are dust seal boots.

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2, and the second pinion shaft 74 is mounted in the auxiliary steering housing 81 via upper and lower bearings 88 and 89 so as to be rotatable and immovable in the axial direction. , The upper opening of the auxiliary steering housing 81 is closed by the lid 111. The second pinion shaft 74 is
The large gear 92 of the hypoid gear mechanism 73 is attached to the upper end by serration coupling or the like. The second rack and pinion mechanism 75 is formed by meshing a second pinion 95 formed on the second pinion shaft 74 with a second rack 96 formed on the second rack shaft 76. The displacement amount detection sensor 64 is attached to the lid 111 and detects the rotation angle of the second pinion shaft 74 so that the housing 4
6 (see FIG. 2) is a potentiometer that detects the amount of displacement.

The auxiliary steering housing 81 has a rack guide 100 disposed at a center position where the second pinion 95 and the second rack 96 mesh with each other. Rack guide 1
00 serves to push the rear surface of the second rack shaft 76 to the rear surface side of the surface on which the second rack 96 is formed. More specifically, the rack guide 100 is configured to guide the second rack shaft 76 from the side opposite to the second rack 96.
And an adjustment bolt 103 for pushing the guide portion 101 via a compression spring 102.

According to such a rack guide 100,
Adjustment bolt 10 screwed into auxiliary steering housing 81
At 3, the guide part 101 is pressed with an appropriate pressing force via the compression spring 102, so that the guide part 101
6 to the second pinion 95 by applying a preload to the second rack 96.
Can be pressed. In the figure, 104 is a contact member for sliding the back surface of the second rack shaft 76, 105 is a lock nut, 112 is a lid fixing bolt, 113 is a washer,
14 is a nut and 115 is a retaining ring.

FIG. 4 is a sectional view taken along line 4-4 in FIG. 2, and shows that the motor 71 is attached to the vehicle body 41 (see FIG. 1) by bolting the motor 71 to the auxiliary steering housing 81. The electric motor 71 is configured such that the electric motor shaft 71a is arranged sideways so as to be substantially parallel to the second rack shaft 76, and the intermediate shaft 72 is serrated and connected to the tip of the electric motor shaft 71a. That is, the motor shaft 71a is inclined by the angle θ with respect to the second rack shaft 76. The angle θ is, for example, 20 ° to 30 °. The reason for the inclination will be described later (see FIG. 6). The intermediate shaft 72 is mounted rotatably and axially immovable inside the auxiliary steering housing 81 via bearings 116 and 117.

The hypoid gear mechanism 73 has a meshing structure between hypoid gears, which comprises a small diameter small gear 91 formed on the intermediate shaft 72 and a large diameter large gear 92 mounted on the second pinion shaft 74. Therefore, the motor shaft 71a is connected to the second pinion shaft 74 via the hypoid gear mechanism 73.

As described above, the hypoid gear mechanism 73 interposed between the motor shaft 71a and the second pinion shaft 74 is driven by the force from the second pinion shaft 74 on the load side.
Has a self-locking function to prevent driving of the motor. The "self-locking function" refers to a function that allows power transmission from the input side to the output side and prevents power transmission from the output side to the input side. The combination of hypoid gear
Power transmission efficiency (reverse transmission efficiency) in the reverse direction from the load side to the drive side is generally small. The reverse transmission efficiency is further set so as to prevent the electric motor 71 from being driven by the force from the second pinion shaft 74 on the load side. Motor 71 in a stopped state
Is not driven by external force. In the drawing, reference numeral 118 denotes a lock nut, and reference numerals 121 and 122 denote retaining rings.

FIG. 5 is a perspective view of the steering apparatus (first embodiment) according to the present invention, and shows the steering apparatus 10 as viewed from the front. This figure shows the housing 46 on the sub-frame 42.
The stand 125 is attached so as to straddle the
By attaching the auxiliary steering housing 81 to the vehicle 25, the electric motor 71 for moving the housing 46 in the vehicle width direction is attached to the vehicle body 41 (see FIG. 1), and the engine mount 126 is also attached to the stand 125. To indicate that The engine mount 126 is a mounting member for mounting an engine (not shown) on a vehicle body.

FIG. 6 is a plan view of a steering device (first embodiment) according to the present invention. This figure shows that the second rack shaft 76 and the auxiliary steering housing 81 are arranged parallel to the first rack shaft 26. Further, this view shows the housing 46
Since the engine mount 126 is disposed directly above the motor mount 71, the motor 71 is disposed slightly inclined with respect to the housing 46, that is, substantially parallel to the housing 46 so that the motor 71 does not interfere with the engine mount 126. Naturally, when the electric motor 71 does not interfere with other members,
The electric motor 71 can be arranged so that the electric motor shaft 71a (see FIG. 4) is parallel to the first rack shaft 26.

In this manner, the motor 71 can be arranged so that the motor shaft 71a is parallel or substantially parallel to the first rack shaft 26. Also, the second rack shaft 76 is
It can be arranged parallel or substantially parallel to the rack shaft 26. The second bearing portion 44 and the third bearing portion 45 are arranged on both radial sides of the housing 46 in a plan view.

Next, the steering apparatus 1 according to the first embodiment having the above configuration will be described.
The operation of 0 will be described with reference to FIG. In the neutral state shown in FIG. 1, when the large gear 92 is rotated clockwise by a predetermined angle by the electric motor 71 in accordance with the steering condition, the second rack shaft 76 is displaced to the left in the figure. The housing 46 and the first pinion 31 are also displaced to the left in the axial direction of the first rack shaft 26. When the driver is holding the steering wheel 21, the first pinion 31 does not rotate. Therefore, the first rack shaft 26 moves to the left in the axial direction together with the housing 46. Thus, the steered wheels 29, 29 can be steered.

When the large gear 92 is rotated counterclockwise in this state, the housing 46, the first pinion 31, and the first rack shaft 26 also return to the neutral position shown in FIG. On the other hand, by displacing the first rack shaft 26 at the neutral position to the right in the figure, the first rack shaft 26 can be moved to the right in the axial direction as in the case of the left displacement. Thus, the steering of the steered wheels 29, 29 can be controlled independently of the driver's steering operation.

Further, while steering the steering wheel 21, the large gear 92 can be rotated by the electric motor 71 in accordance with the steering conditions. The total movement amount S0 of the first rack shaft 26 in the axial direction is obtained by synthesizing the movement amount S1 of the first rack shaft 26 by the electric motor 71 with the movement amount S1 of the first rack shaft 26 by the driver's handle operation. (S0 = S
1 ± S2). Therefore, the steered wheels 29, 29 can be steered largely by adding the movement amount of the first rack shaft 26, or can be steered by subtracting the movement amount of the first rack shaft 26.

In the auxiliary steering mechanism 60, since the second pinion shaft 74 is connected to the motor shaft 71a via the hypoid gear mechanism 73, the second pinion shaft 74 extends in a direction perpendicular to the motor shaft 71a. Also, the second
Since the second rack shaft 76 is connected to the pinion shaft 74 via the second rack and pinion mechanism 75, the second rack shaft 76 extends in a direction orthogonal to the second pinion shaft 74. Therefore, by appropriately setting the gear arrangement of the hypoid gear mechanism 73 and the second rack and pinion mechanism 75, the electric motor 71 can be arranged such that the electric motor shaft 71a is parallel or substantially parallel to the second rack shaft 76. it can.

On the other hand, the first rack shaft 26 is
When the second rack shaft 76 is connected to the housing 46, the second rack shaft 76 can be arranged parallel or substantially parallel to the first rack shaft 26. As a result,
The electric motor 71 can be arranged so that the electric motor shaft 71a is parallel or substantially parallel to the first rack shaft 26. In this way, by reducing the protrusion distance of the electric motor 71 and the second rack shaft 76 in the radial direction of the first rack shaft 26, the entire steering device 10 can be reduced in size. Since the steering device 10 is small, it can be easily arranged in a narrow space such as in the engine room of the vehicle or under the floor.
Since the arrangement is easy, the degree of freedom in vehicle design can be increased.

Further, the auxiliary steering mechanism 60 moves the housing 46 in the vehicle width direction by transmitting the driving torque of the electric motor 71 to the housing 46 via the hypoid gear mechanism 73 and the second rack and pinion mechanism 75. Configuration. Therefore, the amount of movement of the housing 46 with respect to the rotation angle of the electric motor 71 is always proportional. As a result, the proportional control range when controlling the amount of movement of the housing 46 is wide, so that the steered wheels 29, 29
Can be controlled with higher accuracy.
Moreover, the movement control range of the housing 46 can be set to be large despite the use of the small steering device 10 as described above.

Next, the steering apparatus according to the second embodiment will be described with reference to FIGS.
A description will be given based on FIG. FIG. 7 is a schematic diagram of a steering device (second embodiment) according to the present invention, and shows the steering device 2 viewed from above.
00 is schematically shown. The steering device 200 according to the second embodiment includes a front wheel steering mechanism 210 that controls the left and right front wheels 2.
19 and 219, and a rear wheel steering mechanism 230
This is a four-wheel steering device in which the left and right rear wheels 249, 249 are steered.

The front wheel steering mechanism 210 connects a first pinion shaft 214 to a steering wheel 211 via a steering shaft 212 and universal joints 213 and 213, and connects to the first pinion shaft 214 via a first rack and pinion mechanism 215. To connect the first rack shaft 216
Left and right front wheels 219, 2 are connected to a rack shaft 216 via left and right tie rods 217, 217 and knuckles 218, 218.
19 are connected. The first rack and pinion mechanism 215 is configured by meshing a first pinion 221 provided on a first pinion shaft 214 with a first rack 222 provided on a first rack shaft 216. Such a front wheel steering mechanism 210 includes a first housing 22 fixed to a vehicle body.
5, a first pinion shaft 214 is mounted rotatably and immovable in the axial direction, and a first rack shaft 216 is mounted movably in the vehicle width direction (axial direction).

On the other hand, the rear wheel steering mechanism 230 is
The electric motor 2 based on the predetermined steering conditions set in advance in 1.
By driving the motor 41, the second rack shaft 246 is moved in the vehicle width direction by the electric motor 241, and the rear wheels 249, 249 are steered. The control unit 231 detects, for example, a steering angle sensor 232 that detects a steering angle of the steering wheel 211, a vehicle speed sensor 233 that detects a traveling speed of the vehicle, and a displacement detection sensor 234 that detects a displacement of the second rack shaft 246. It has a function of driving and controlling the electric motor 241 according to a signal.

More specifically, the rear wheel steering mechanism 2
30 is an output shaft 241a of the motor 241 (the motor shaft 24
1a), a second pinion shaft 244 is connected via a hypoid gear mechanism 243, and the second rack shaft 24 is connected to the second pinion shaft 244 via a second rack and pinion mechanism 245.
6 and connect the left and right tie rods 2 to the second rack shaft 246.
47 and 247 and left and right rear wheels 249 and 249 are connected via knuckles 248 and 248. The second rack and pinion mechanism 245 includes a second pinion shaft 244.
The second pinion 251 of the second rack 252 and the second rack 252 of the second rack shaft 246 are engaged with each other.

In the rear wheel steering mechanism 230, a second pinion shaft 244 extending in the front-rear direction and a second rack shaft 246 extending in the vehicle width direction are housed in a second housing 262. That is, the second housing 262 fixed to the vehicle body 261 has the second pinion shaft 244 rotatably and axially immovable mounted thereon, and the second rack shaft 246 mounted movably in the vehicle width direction (axial direction). Things.

FIG. 8 is a rear view of a rear wheel steering mechanism (second embodiment) according to the present invention, and shows a main portion in section. The left and right ends of the second rack shaft 246 project from the second housing 262, and tie rods 247, 247 are connected via universal joints (ball joints) 263, 263.
It is connected to. The second housing 262 is
The storage member is disposed so as to be parallel to the rack shaft 246 and is concentric with the second rack shaft 246 and elongated in the vehicle width direction. In the figure, 264 is a bearing, and 265 and 265 are dust seal boots.

FIG. 9 is a sectional view taken along the line 9-9 in FIG.
This shows that the horizontal second pinion shaft 244 is rotatably and axially immovably mounted in the housing 262 via bearings 271 and 272, and the rear opening of the second housing 262 is closed by the lid 273. Second pinion shaft 244
Is the large gear 302 of the hypoid gear mechanism 243 at the rear end.
Are attached by serration connection or the like. The displacement amount detection sensor 234 is attached to the lid 273 and detects the rotation angle of the second
This is a potentiometer that detects the amount of displacement of the rack shaft 246.

The second housing 262 includes a second pinion 2
A rack guide 280 is arranged at a center position where the first rack 51 and the second rack 252 mesh with each other. Rack guide 2
80 serves to push the rear surface of the second rack shaft 246 toward the rear surface of the surface on which the second rack 252 is formed. More specifically, the rack guide 280 is a second rack 2
The guide portion 281 contacts the second rack shaft 246 from the side opposite to the position 52, and the adjusting bolt 283 pushes the guide portion 281 via a compression spring 282.

According to such a rack guide 280,
The guide portion 281 is pressed with an appropriate pressing force via the compression spring 282 by the adjusting bolt 283 screwed into the second housing 262, so that the second rack 252 is
To the second rack 252 and the second pinion 25
1 can be pressed. In the figure, 274 is a lid fixing bolt, 275 is a washer, 276 is a nut, 277
Is a retaining ring, 284 is a contact member for sliding the rear surface of the second rack shaft 246, and 285 is a lock nut.

FIG. 10 is a sectional view taken along line 10-10 of FIG. 9, and shows that the motor 241 is attached to the vehicle body (see FIG. 7) by bolting the motor 241 to the second housing 262. The motor 241 is disposed sideways so that the motor shaft 241a is parallel to the second rack shaft 246,
An intermediate shaft 242 is serration-coupled to a tip of a motor shaft 241a. The intermediate shaft 242 includes bearings 291,
It is attached to the inside of the second housing 262 via a shaft 92 so as to be rotatable and immovable in the axial direction.

The hypoid gear mechanism 243 includes the intermediate shaft 24
2, a small gear 301 having a small diameter and a second pinion shaft 2
A hypoid gear meshing structure composed of a large-diameter large gear 302 attached to the gear 44. Therefore, the motor shaft 241a is connected to the second pinion shaft 244 via the hypoid gear mechanism 243.

Thus, the hypoid gear mechanism 243 interposed between the motor shaft 241a and the second pinion shaft 244
Has a self-locking function that prevents the electric motor 241 from being driven by the force from the second pinion shaft 244 on the load side. The “self-locking function” is the same function as the hypoid gear mechanism 73 of the first embodiment described with reference to FIG. 4 and will not be described in detail. The motor 241 in the stopped state is not driven by the external force. In the figure, 293 is a lock nut, and 294 and 295 are retaining rings.

Next, the steering apparatus 2 according to the second embodiment having the above configuration will be described.
The operation of 00 will be described with reference to FIG. By steering the steering wheel 211, the front wheel steering mechanism 210
, The front wheels 219, 219 can be steered.
On the other hand, the rear wheel steering mechanism 230 is driven by the driving torque generated by the electric motor 241 according to the steering conditions, via the hypoid gear mechanism 243, the second pinion shaft 244, the second rack and pinion mechanism 245, and the second rack shaft 246. The steering of the wheels 249, 249 can be controlled. Thus, the left and right front wheels 219, 219 and the left and right rear wheels 24
9,249 can be steered.

In the rear wheel steering mechanism 230, since the second pinion shaft 244 is connected to the motor shaft 241a via the hypoid gear mechanism 243, the second pinion shaft 2
44 extends in a direction orthogonal to the motor shaft 241a. Further, since the second rack shaft 246 is connected to the second pinion shaft 244 via the second rack and pinion mechanism 245, the second rack shaft 2 connected to the rear wheels 249, 249 is also provided.
46 extends in a direction orthogonal to the second pinion shaft 244. Therefore, by appropriately setting the gear arrangement of the hypoid gear mechanism 243 and the second rack and pinion mechanism 245, the electric motor 241 can be arranged such that the electric motor shaft 241a is parallel or substantially parallel to the second rack shaft 246. it can.

In this way, by reducing the projecting distance of the electric motor 241 in the radial direction of the second rack shaft 246, the entire rear wheel steering mechanism 230 can be downsized. Since it is a small rear wheel steering mechanism 230, it can be easily arranged in a narrow space such as in the engine room of the vehicle or under the floor. Since the arrangement is easy, the degree of freedom in vehicle design can be increased.

Further, the rear wheel steering mechanism 230 includes the electric motor 24
The first drive torque is applied to the hypoid gear mechanism 243 and the second drive torque.
By transmitting the second rack shaft 246 to the second rack shaft 246 via the rack and pinion mechanism 245, the second rack shaft 246 is moved in the vehicle width direction. Therefore, the amount of movement of the second rack shaft 246 with respect to the rotation angle of the electric motor 241 is always proportional. As a result, since the proportional control range when controlling the movement amount of the second rack shaft 246 is wide, the motor 24
1 can control the steering of the steered wheels 249, 249 with even higher accuracy. In addition, the movement control range of the second rack shaft 246 can be set large even though the steering device 200 is small as described above.

In the above embodiment of the present invention,
The presence or absence of the intermediate shafts 72 and 242 is optional.
a, 241a may be provided with the small gears 91, 301 directly.

Further, the steering devices 10 and 200 may be provided with a worm gear mechanism having a self-locking function instead of the hypoid gear mechanisms 73 and 243. When the hypoid gear mechanism 73 is changed to a worm gear mechanism, a worm may be connected to the electric motor shaft 71a or the intermediate shaft 72, and a worm wheel may be connected to the second pinion shaft 74. On the other hand, when the hypoid gear mechanism 243 is changed to a worm gear mechanism, the motor shaft 241a
Alternatively, a worm may be connected to the intermediate shaft 242, and a worm wheel may be connected to the second pinion shaft 244. Naturally, even when the hypoid gear mechanisms 73 and 243 are changed to worm gear mechanisms, the same functions and effects as those of the hypoid gear mechanisms 73 and 243 are obtained, and the self-locking function is also provided. .

[0057]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, the second pinion shaft is connected to the motor shaft of the motor that generates the housing drive torque via a hypoid gear mechanism or a worm gear mechanism, so that the second pinion shaft extends in a direction orthogonal to the motor shaft. Can be. Since the second rack shaft is connected to the second pinion shaft via a rack and pinion mechanism, the second rack shaft is connected to the second rack shaft.
It can extend in a direction perpendicular to the pinion axis.
Therefore, the motor can be arranged such that the motor axis is parallel or substantially parallel to the second rack axis. On the other hand, when the first rack shaft connected to the steered wheels is housed in the housing, and the second rack shaft is connected to the housing, the second rack shaft can be arranged parallel or substantially parallel to the first rack shaft. . Therefore, the motor can be arranged such that the motor axis is parallel or substantially parallel to the first rack axis.
In this way, by reducing the projecting distance of the second rack shaft or the electric motor in the radial direction of the first rack shaft, the steering device can be downsized. Since a small steering device can be arranged in a narrow space such as in the engine room of the vehicle or under the floor, the degree of freedom in designing the vehicle is increased.

Further, since the self-locking function is provided by connecting the motor shaft to the second pinion shaft via a hypoid gear mechanism or a worm gear mechanism, the force from the load side is transmitted to the drive side. Can be blocked. Therefore, the stopped housing does not move. The position of the first pinion does not change due to the reaction force from the steered wheels. Even at this time, the steered wheels can be steered by the steering wheel via the first rack shaft.

Further, in the first aspect, the power torque of the electric motor is transmitted to the housing via the hypoid gear mechanism or the worm gear mechanism and the second rack and pinion mechanism, so that the housing is moved in the vehicle width direction. The amount of movement of the housing with respect to the rotation angle of the electric motor can always be made proportional. As a result, since the proportional control range when controlling the amount of movement of the housing is wide, the auxiliary steering of the steered wheels by the electric motor can be controlled with higher accuracy. In addition, the movement control range of the housing can be set large even though the steering device is small as described above.

According to a second aspect of the present invention, in the four-wheel steering system, the pinion shaft is connected to the motor shaft of the motor that generates the rear wheel steering torque via a hypoid gear mechanism or a worm gear mechanism, so that the pinion shaft is orthogonal to the motor shaft. It can be extended in the direction of. Since the rack shaft is connected to the pinion shaft via the rack and pinion mechanism, the rack shaft connected to the rear wheel can be extended in a direction perpendicular to the pinion shaft. Therefore, the motor can be arranged such that the motor axis is parallel or substantially parallel to the rack axis. Thus, the steering device can be downsized by reducing the projecting distance of the electric motor projecting in the radial direction of the rack shaft. Since a small steering device can be arranged in a narrow space such as under the floor of the vehicle, the degree of freedom in designing the vehicle is increased.

Further, since the self-locking function is provided by connecting the motor shaft to the pinion shaft via a hypoid gear mechanism or a worm gear mechanism, transmission of the force from the load side to the drive side is prevented. be able to. Therefore, the stopped rack axis does not move. The position of the rack shaft does not change due to the reaction force from the rear wheel. Even at this time, the steered wheels can be steered by the steering wheel via the rack shaft.

Furthermore, in the second aspect, the power torque of the electric motor is transmitted to the rack shaft via a hypoid gear mechanism or a worm gear mechanism and a rack and pinion mechanism, so that the rack shaft is moved in the vehicle width direction. The amount of movement of the rack shaft with respect to the rotation angle of the electric motor can always be made proportional. As a result, the proportional control range when controlling the movement amount of the rack shaft is wide, so that the steering of the rear wheels by the electric motor can be controlled with higher accuracy.
In addition, the movement control range of the rack shaft can be set large even though the steering device is small as described above.

[Brief description of the drawings]

FIG. 1 is a schematic view of a steering device (first embodiment) according to the present invention.

FIG. 2 is a front view of an auxiliary steering mechanism (first embodiment) according to the present invention.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a perspective view of a steering device (first embodiment) according to the present invention.

FIG. 6 is a plan view of a steering device (first embodiment) according to the present invention.

FIG. 7 is a schematic diagram of a steering device (second embodiment) according to the present invention.

FIG. 8 is a rear view of a rear wheel steering mechanism (second embodiment) according to the present invention.

9 is a sectional view taken along line 9-9 in FIG.

FIG. 10 is a sectional view taken along line 10-10 of FIG. 9;

[Explanation of symbols]

10 steering device, 21 steering wheel, 24 ...
1st pinion shaft, 26 ... 1st rack shaft, 29 ... Steering wheel (front wheel), 31 ... 1st pinion, 32 ... 1st rack, 4
DESCRIPTION OF SYMBOLS 1 ... Body, 46 ... Housing, 71 ... Electric motor, 71a ...
Motor shaft, 73: hypoid gear mechanism, 74: second pinion shaft, 76: second rack shaft, 95: pinion of second pinion shaft (second pinion), 96: rack of second rack shaft (second rack), 200: steering device, 219: front wheels,
241, an electric motor, 241a ... an electric motor shaft, 243 ... a hypoid gear mechanism, 244 ... a pinion shaft (second pinion shaft), 245 ... a rack and pinion mechanism (second rack and pinion mechanism) (Second rack shaft), 249: rear wheel, 261: vehicle body.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takuya Yamaguchi 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Inventor Go Nishimori 1-4-1 Chuo, Wako-shi, Saitama Inside the Honda R & D Co., Ltd. (72) Inventor Keiichi Takikawa 1-4-1 Chuo, Wako-shi, Saitama F-term in the Honda R & D Co., Ltd. 3D033 CA02 CA05 CA23 JB02 JB17

Claims (2)

[Claims] A first pinion shaft connected to a steering wheel and having a first pinion is rotatably mounted on a housing, and a first rack shaft having a first rack engaged with the first pinion and connected to a steering wheel is provided. Attached to the housing so as to be movable in the vehicle width direction, this housing is attached to the vehicle body so as to be movable in the vehicle width direction, and an electric motor for moving the housing in the vehicle width direction is attached to the vehicle body. In the steering device, the steering wheel can be steered by causing the motor shaft to be parallel or substantially parallel to the first rack shaft, and the motor shaft is connected to a hypoid gear mechanism or It is connected to a second pinion shaft via a worm gear mechanism, and the pinion of the second pinion shaft is connected to a second rack. Engagement to the axis of the rack, attaching the second rack shaft to the vehicle body movably in the vehicle width direction, wherein the second rack shaft first
A steering device arranged so as to be parallel or substantially parallel to a rack axis and connected to the housing. 2. A steering device for steering left and right front wheels and left and right rear wheels, wherein a rack shaft extending in a vehicle width direction and connected to the rear wheel is moved in a vehicle width direction by an electric motor mounted on a vehicle body. Thus, in the steering device configured to steer the rear wheel, the motor is arranged so that the motor shaft is parallel or substantially parallel to the rack shaft, and the motor shaft is connected to a pinion via a hypoid gear mechanism or a worm gear mechanism. A steering device, wherein a shaft is connected, and the rack shaft is connected to the pinion shaft via a rack and pinion mechanism.