JP3248426B2 - Vehicle steering system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering apparatus in which a pinion shaft connected to a steering wheel is connected to a rack shaft for turning steered wheels.

[0002]

2. Description of the Related Art In a vehicular steering system in which a pinion shaft connected to a steering wheel is connected to a rack shaft for turning steered wheels, a power assist based on an input torque of the pinion shaft is performed to perform rotation. 2. Description of the Related Art A steering device (power steering device) configured to steer a steering wheel is known (for example, Japanese Patent Application Laid-Open No. 57-167869).

In the steering apparatus disclosed in the above publication, a pinion shaft meshing with a rack shaft is supported so as to be swingable.
It swings according to the steering torque. A hydraulic control valve is connected to the pinion shaft, and the hydraulic control valve is operated by swinging of the pinion shaft. As a result, the hydraulic pressure is controlled in accordance with the steering torque, and predetermined power assist is performed.

However, in the conventional steering apparatus disclosed in the above publication, the pinion shaft swings around the fulcrum and is displaced with respect to the rack axis. Therefore, the pinion shaft is displaced with respect to the rack shaft. The state of meshing of the teeth with the rack shaft changes. That is, there is a disadvantage that the engagement of the rack and pinion is displaced in a direction in which the engagement of the rack and the pinion is separated, and the engagement rigidity is reduced.

[0005]

SUMMARY OF THE INVENTION In consideration of the above fact, the present invention can reduce the change in the meshing state of the teeth of the pinion shaft and the rack shaft to secure a predetermined rigidity, and can respond to the steering torque. It is possible to perform power assist,
It is another object of the present invention to provide a vehicular steering device capable of suppressing transmission of excessive reverse input to a pinion shaft.

[0006]

According to a first aspect of the present invention, there is provided a steering apparatus for a vehicle, wherein a pinion shaft connected to a steering wheel is connected to a rack shaft for turning steered wheels. In the picking device, one end is attached to the housing, the other end rotatably supports the pinion shaft, and the pinion shaft is arranged along the rack axis and the axis of the pinion shaft according to the magnitude of the steering torque.
A supporting member for supporting the movable member along the linear direction ;
And the housing is provided with an axial displacement of the pinion shaft.
Sometimes the pinion shaft comes into contact with the pinion shaft and
A friction damping portion for damping the rotation of the shaft .

In the vehicle steering apparatus according to the first aspect, when the pinion shaft is steered through the steering wheel,
This steering force is transmitted via the rack shaft, and the steered wheels are steered.

[0008] Here, immediately after steering, the rack shaft (that is, the steered wheel side) has a large resistance, so that the rack shaft is immobile, and the pinion shaft is displaced along the rack shaft via the support member. In this case, the pinion shaft is not simply configured to swing around the fulcrum and displaced with respect to the rack axis, but is supported by the support member so as to be displaceable along the rack axis. The change in the meshing state of the teeth of the pinion shaft and the rack shaft is reduced. That is, the predetermined rigidity can be secured without lowering the meshing rigidity due to the displacement of the rack and pinion meshing in a direction in which the rack and pinion mesh with each other. Further, the vehicle according to claim 1.
In the steering device, the pinion shaft is displaced along the rack axis.
Not only can it be displaced, but also along its own axis
It is. Therefore, for example, a steered wheel
If the reverse input is transmitted from the side via the rack shaft,
Due to the component force of this reverse input, the pinion shaft
Displaced along the direction, the friction damping part contacts the pinion shaft
You. This reduces the rotation of the pinion shaft due to frictional force.
The damped, excessive reverse input is caused by the pinion axis (that is, the steer axis).
Transmission to the ring wheel)
Back is reduced.

According to a second aspect of the present invention, there is provided a vehicle steering system comprising:
2. The vehicle steering apparatus according to claim 1, further comprising: a displacement detection unit configured to detect a displacement of the support member in the rack axis direction, wherein power assist is performed based on a detection result by the displacement detection unit. .

[0010] In the vehicle steering apparatus according to the second aspect, the displacement of the support member in the rack axis direction is detected by the displacement detecting means, and power assist is performed based on the detection result.

Here, the displacement of the support member in the rack axis direction corresponds to the magnitude of the steering torque from the pinion shaft. Therefore, the steering torque can be detected by detecting the displacement of the support member in the rack axis direction by the displacement detection means, and the power assist based on the steering torque can be performed by performing the power assist based on the steering torque. it can.

[0012]

[0013]

[0014]

1 to 5 schematically show a vehicle steering apparatus 10 according to a first embodiment of the present invention in a schematic sectional view.

The vehicle steering system 10 is applied, for example, as an electric power steering system for a vehicle.
A pinion shaft (steering shaft) 12 is provided. Pinion shaft 1
2, a steering wheel (not shown) is attached, and is disposed in a direction substantially orthogonal to the rack shaft 24.
The housing 19 is supported by a support beam 200 as a support member.
4 is supported. The support beam 200 has four legs 201
The ends of these legs 201 are fixed to the housing 194. The pinion shaft 12 is rotatably supported on the top of the support beam 200 by bearings 203 and 205. That is, the pinion shaft 12 is configured to be cantilevered by the support beam 200. Further, a pinion 196 is provided on the pinion shaft 12 and meshes with a rack gear 198 of the rack shaft 24.

Here, the support beam 200 that rotatably supports the pinion shaft 12 has flexibility along the axial direction of the rack shaft 24, so that the pinion shaft 12 is aligned with the axis of the rack shaft 24. It can be displaced along the direction.

One end of a lever 202 is connected to the top of the support beam 200 (near the bearing 203). Therefore, when the pinion shaft 12 is displaced along the rack shaft 24 together with the support beam 200, the lever 202 is moved in the longitudinal direction.

Further, the vehicle steering system 10 includes a motor unit 34. The motor unit 34 is a so-called print motor, and includes an armature 36 and first and second magnetic poles 38 and 4 provided on both sides of the armature 36.
0. A motor rotation shaft 42 is fixed to the center of the armature 36, and the motor rotation shaft 42 is rotatably supported by the housing 16. Armature 3
6 is provided with a gear 204 on the motor rotation shaft 42, and further connected to a rack gear 210 of the rack shaft 24 via a reduction gear 206 and a pinion 208.

On the other hand, the first magnetic pole piece 38 and the second magnetic pole piece 40 are fixed to the housing 16 so as to face both sides of the armature 36, respectively.

Further, a limit switch 214 is provided integrally with the motor section 34. As shown in FIG. 5, the limit switch 214 is connected to the lever 202 described above.
The operating state of the pinion shaft 12 (the left-right switching state) can be detected by moving the operating contact 216 connected to the right and left to contact the fixed contacts 217 and 219 respectively. The limit switch 214 is connected to the brushes 76 and 78 of the motor unit 34, and can switch the direction of energization to the motor unit 34 (armature 36) in accordance with the steering direction of the pinion shaft 12.

Further, a displacement sensor 207 as a displacement detecting means is arranged corresponding to an intermediate portion of the lever 202. When the displacement sensor 207 is engaged with the lever 202, the displacement amount of the lever 202,
A displacement of 0 (pinion shaft 12) can be detected.
This displacement sensor 207 is connected to the ECU 209. The ECU 209 determines a displacement amount of the support beam 200 (the pinion shaft 12) detected by the displacement sensor 207,
The limit switch 214 (the brush 76 of the motor unit 34,
The current supplied to the brush 78) is controlled.

Next, the operation of the first embodiment will be described. In the vehicle steering device 10 having the above-described configuration, when the steering wheel (pinion shaft 12) is not steered (the vehicle is traveling straight), as shown in FIG.
The operating contact 216 of 14 does not move, the limit switch 214 is turned off, and the motor section 34 is not energized.

Steering wheel (pinion shaft 12)
Is steered, the motor unit 34 is operated according to the steering torque.

That is, when the pinion shaft 12 is steered in either the left or right direction, for example, when turning right as shown by the arrow A in FIG. 1, the steering force of the pinion shaft 12 is transmitted via the pinion 196 and the rack gear 198. The power is transmitted to the rack shaft 24, and the rack shaft 24 is driven in the axial direction (the direction of arrow D) to steer the steered wheels.

In this case, immediately after the pinion shaft 12 is steered, the rack shaft 24 (that is, the tire side) has a large resistance, so that the rack shaft 24 is immobile. Is slightly displaced along. Thus, the displacement of the pinion shaft 12 causes the lever 202 to move in the longitudinal direction. With the movement of the lever 202, the displacement sensor 207 causes the lever 2 to move.
02, that is, the support beam 200 (pinion shaft 12)
Of the ECU 20 based on the detection result.
Reference numeral 9 controls the value of the current supplied to the limit switch 214. Further, by the movement of the lever 202, FIG.
As shown in FIG.
Moves, the limit switch 214 is turned on, and the motor section 34 (armature 36) is energized, and the armature 36 of the motor section 34 rotates.

As a result, the driving force of the motor section 34 acts on the rack shaft 24 to which the motor rotating shaft 42 is connected, and is applied as an auxiliary driving force. Therefore, the pinion shaft 12
The steering force of the (steering wheel) is reduced.

On the other hand, when the pinion shaft 12 is steered to the left (in the direction of arrow C in FIG. 1), the steering force of the pinion shaft 12 is transmitted to the rack shaft 2 via the pinion 196 and the rack gear 198.
4, the rack shaft 24 is driven in the axial direction (arrow B direction), and the steered wheels are steered.

In this case as well, immediately after the pinion shaft 12 is steered, the rack shaft 24 (that is, the tire side) has a large resistance, so that the rack shaft 24 is immovable. Displaces slightly along axis 24. Thus, the displacement of the pinion shaft 12 causes the lever 202 to move in the longitudinal direction. With the movement of the lever 202, the displacement sensor 207 moves the lever 202, that is, the support beam 200 (pinion shaft 1).
2) the displacement is detected, and based on the detection result, the ECU
209 controls the value of the current supplied to the limit switch 214. Further, the movement of the lever 202 causes
As shown in (A), the operating contact 216 of the limit switch 214 moves in the opposite direction to the above with the movement of the lever 202, and the limit switch 214 is turned on, and the motor unit 3
4 (the armature 36) and the armature 3 of the motor section 34
6 rotates in the opposite direction to that described above.

Thus, the driving force of the motor section 34 acts on the rack shaft 24 to which the motor rotating shaft 42 is connected, and is applied as an auxiliary driving force. Therefore, the pinion shaft 12
The steering force of the (steering wheel) is reduced.

In this case, the amount of movement of the lever 202 detected by the displacement sensor 207, that is, the amount of displacement of the support beam 200 that supports the pinion shaft 12, corresponds to the magnitude of the steering torque from the pinion shaft 12. The detection value of the sensor 207 is changed according to the magnitude of the steering torque. Accordingly, the driving force of the motor unit 34 increases and decreases in accordance with the steering torque, and performs power assist based on the steering torque from the pinion shaft 12 to perform predetermined power assisting, similarly to the conventional hydraulic power steering device. Output torque can be applied to the rack shaft 24.

When the steering wheel (pinion shaft 12) is switched between left and right, the direction of energization of the motor unit 34 to the armature 36 is switched by the operation of the lever 202 and the limit switch 214 as described above.
The rotation direction of the motor rotation shaft 42 is switched to correspond to the steering direction of the pinion shaft 12.

Further, in the vehicle steering apparatus 10, when the pinion shaft 12 is displaced along the rack shaft 24 via the support beam 200 (during steering), the pinion shaft 12 simply swings around the fulcrum. To move the rack shaft 24
Is not displaced with respect to the rack beam 24, but is displaceably supported along the rack shaft 24 by the support beam 200.
Even if the pinion shaft 12 is displaced, the change in the meshing state of the teeth between the pinion 196 of the pinion shaft 12 and the rack gear 198 of the rack shaft 24 is reduced. That is, the pinion 19
The predetermined rigidity can be ensured without the meshing rigidity being reduced due to the displacement of the meshing between the gear 6 and the rack gear 198 in the direction away from each other. Therefore, the operation accuracy does not decrease due to the decrease in rigidity.

As described above, in the vehicle steering system 10 according to the first embodiment, the pinion shaft 12 is connected to the support beam 200.
As a result, the pinion 196 and the rack gear 198 can be engaged with each other so as to be displaceably supported along the rack shaft 24, so that rigidity can be ensured. Further, the pinion shaft 12
The displacement of the (supporting beam 200) is detected by the displacement sensor 207, and the drive control of the motor unit 34 is performed according to the steering torque, so that the steering force can be favorably assisted. Further, the structure is simple, and the cost and the size and weight can be significantly reduced.

When a strain gauge is attached to the support beam 200 instead of the displacement sensor 207, the steering torque can be detected with high sensitivity and high accuracy, and a phenomenon such as flutter in a relatively high frequency region can be obtained. Can be detected. Furthermore, if the rigidity of the support beam 200 is appropriately adjusted, a rack guide or the like that supports the rack shaft 24 can be omitted.

Next, another embodiment of the present invention will be described. The same reference numerals as in the first embodiment denote the same parts as those in the first embodiment, and a description thereof will be omitted.

FIGS. 6 to 8 schematically show the overall structure of a vehicle steering system 220 according to a second embodiment of the present invention in a sectional view.

This vehicle steering device 220 has the same configuration as the above-described vehicle steering device 10 such as the pinion shaft 12 and the support beam 200, and further includes a hydraulic control valve 222 in place of the motor section 34. Have been. This hydraulic control valve 22
2 is connected to the pump 224 and the rack shaft 24
Are connected to the left and right cylinder chambers 226 and 228, and can adjust and supply the oil liquid to the respective cylinder chambers 226 and 228. Also, the spool 22 of the hydraulic control valve 222
Numeral 3 is connected to the above-described lever 202, and is configured to be actuated by displacement of the pinion shaft 12 (support beam 200).

In this vehicle steering device 220, when the steering wheel (pinion shaft 12) is steered, the pinion shaft 12 is displaced along with the support beam 200 along the rack shaft 24 in accordance with the steering torque, as described above. I do. Thus, the displacement of the pinion shaft 12 causes the lever 202 to move in the longitudinal direction. With the movement of the lever 202, the hydraulic control valve 222 operates, and the left and right cylinder chambers 2
The oil liquid is adjusted and sent to 26 and 228. Thereby, the auxiliary driving force is applied to the rack shaft 24, and the steering force of the pinion shaft 12 (steering wheel) is reduced.

In this case, the amount of operation of the hydraulic control valve 222 by the lever 202, that is, the amount of displacement of the support beam 200 that supports the pinion shaft 12, corresponds to the magnitude of the steering torque from the pinion shaft 12. The operation amount of the valve 222 is changed according to the magnitude of the steering torque. Therefore, the hydraulic pressure applied to the cylinder chambers 226 and 228 increases and decreases in accordance with the steering torque, and power assist based on the steering torque from the pinion shaft 12 is performed similarly to the conventional hydraulic power steering device. As a result, a predetermined output torque can be applied to the rack shaft 24.

Further, also in this vehicle steering device 220, the pinion shaft 12 is supported by the support beam 200 so as to be displaceable along the rack shaft 24 as in the first embodiment. Even if the pinion shaft 12 is displaced, the pinion 196 of the pinion shaft 12 and the rack shaft 24
The change in the meshing state of the teeth with the rack gear 198 is reduced. That is, the pinion 196 and the rack gear 198
The predetermined rigidity can be ensured without the meshing rigidity being reduced due to the displacement of the meshing in the direction in which the meshing is separated.
Therefore, the operation accuracy does not decrease due to the decrease in rigidity.

As described above, in the vehicle steering apparatus 220 according to the second embodiment, the pinion shaft 12 is
Since the pinion 196 and the rack gear 198 are displaceably supported along the rack shaft 24, the engagement rigidity between the pinion 196 and the rack gear 198 can be ensured. Furthermore, the pinion shaft 1
The hydraulic control valve 222 is operated by the displacement of 2 (support beam 200) to perform hydraulic control according to the steering torque.
The steering force can be favorably assisted. Further, the structure is simple, and the cost and the size and weight can be significantly reduced.

FIGS. 9 and 10 are schematic sectional views showing the entire structure of a vehicle steering system 230 according to a third embodiment of the present invention.

The vehicle steering device 230 includes the motor portion 34 of the vehicle steering device 10 and the vehicle steering device 22 described above.
It is configured as a manual steering device in which the zero hydraulic control valve 222 is omitted. The configurations of the pinion shaft 12 and the support beam 200 are the same as those of the vehicle steering devices 10 and 22 described above.
0, but the legs 201 of the support beam 200
Has a thin middle portion as shown in FIG.
Thus, the pinion shaft 12 is supported so as to be displaceable even in the axial direction.

The housing 194 facing the tip of the pinion shaft 12 is provided with a friction damping portion 232. A slight clearance is provided between the friction damping portion 232 and the pinion shaft 12, and the pinion shaft 12 is normally separated from the friction damping portion 232. Further, a friction damping portion 234 is provided in the housing 194 facing the inner race 203A of the bearing 203 that supports the pinion shaft 12. A slight clearance is provided between the friction damping portion 234 and the inner race 203A of the bearing 203, and the inner race 203A is usually separated from the friction damping portion 234.

In this vehicle steering device 230, when the steering wheel (pinion shaft 12) is steered, the steering force of the pinion shaft 12 is reduced by the pinion 196 and the rack gear 1
98 and transmitted to the rack shaft 24 via the rack shaft 24.
Is driven in the axial direction, and the steered wheels are steered.

Here, in this vehicle steering device 230,
The pinion shaft 12 (support beam 200) can be displaced not only along the rack shaft 24, but also along its own axial direction. Therefore, for example, when a reverse input is transmitted from the steered wheel side via the rack shaft 24 due to a curb collision or the like, the pinion shaft 1 is caused by the component force of the reverse input.
2 is displaced along its own axial direction, and the tip of the pinion shaft 12 and the friction damping portion 232 or the inner race 203A of the bearing 203 and the friction damping portion 234 come into contact with each other.
As a result, the pinion shaft 12
Is attenuated, and excessive reverse input is suppressed from being transmitted to the pinion shaft 12 (that is, the steering wheel), and kickback is reduced.

As described above, in the vehicle steering device 230 according to the third embodiment, not only the engagement rigidity between the pinion 196 and the rack gear 198 can be ensured, but also an excessive reverse input causes the pinion shaft 12 To be transmitted to the vehicle.

Note that in the third embodiment,
Although the example in which the vehicle steering device 230 is configured as a so-called manual steering device and provided with the friction damping unit 232 and the friction damping unit 234 has been described, the invention is not limited thereto. A frictional damping unit 232 is provided to an electric power steering device such as an electric power steering device or a hydraulic power steering device such as a vehicle steering device 220.
Of course, it is also possible to apply the friction damping part 234.

[0049]

As described above, in the vehicle steering system according to the first aspect, it is possible to reduce a change in the state of meshing of the teeth between the pinion shaft and the rack shaft, thereby securing a predetermined rigidity. without the operation accuracy decreases due to the decrease, and
Furthermore, excessive reverse input is prevented from being transmitted to the pinion shaft.
Control can also, in the vehicle steering device according to claim 2 has an excellent effect that it is possible to perform power assist according to the steering torque.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a configuration of a vehicle steering system according to a first embodiment of the present invention, as viewed from the front side.

FIG. 2 is a cross-sectional view of the configuration of the vehicle steering system according to the first embodiment of the present invention, as viewed from the rear side.

FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1 showing a configuration of the vehicle steering system according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1 showing the configuration of the vehicle steering system according to the first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram illustrating an operation state of a limit switch of the vehicle steering device according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view of the configuration of a vehicle steering system according to a second embodiment of the present invention, as viewed from the front.

FIG. 7 is a cross-sectional view of the configuration of a vehicle steering system according to a second embodiment of the present invention, as viewed from the rear side.

FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 6 showing a configuration of a vehicle steering system according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of a configuration of a vehicle steering system according to a third embodiment of the present invention, as viewed from the front side.

FIG. 10 is a cross-sectional view taken along line 10-10 in FIG. 9 showing a configuration of a friction damping unit of the vehicle steering system according to the third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vehicle steering device 12 Pinion shaft 24 Rack shaft 34 Motor unit 194 Housing 202 Lever 214 Limit switch 200 Support beam (support member) 201 Leg 207 Displacement sensor (displacement detecting means) 220 Vehicle steering device 222 Hydraulic control valve 230 Vehicle steering device 232 Friction damping part 234 Friction damping part

Claims (2)

(57) [Claims] 1. A steering apparatus for a vehicle, wherein a pinion shaft connected to a steering wheel is connected to a rack shaft for turning steered wheels, wherein one end of the pinion shaft is attached to a housing, and the other end is connected to the pinion shaft. Along with supporting the shaft rotatably, the pinion shaft is moved along the rack shaft according to the magnitude of the steering torque.
And a supporting member for displaceably supported in the axial direction of the pinion shaft and the housing, the axial variations of the pinion shaft
When the pinion shaft is in contact with the
A steering device for a vehicle , comprising a friction damping unit for damping rotation of an on-shaft . 2. The vehicle according to claim 1, further comprising a displacement detection unit that detects a displacement of the support member in the rack axis direction, and performing power assist based on a detection result by the displacement detection unit. Steering gear.