JP2622359B2 - Car steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve for a vehicle hydraulic power steering device, and more particularly to a hydraulic mechanical device for resisting the operation of a power steering control valve.

[0002]

A known power steering device is disclosed in U.S. Pat. No. 4,819,545. The power steering apparatus includes a control valve assembly having coaxial inner and outer valve members. A plurality of rollers are arranged between a cam surface formed on the outer valve member and a cam surface of the annular force transmission ring. The force transmission ring is
The spring is pressed against these rollers. Due to the action of the pressurized hydraulic pressure acting on the force transmission ring, the rollers and the cam surface cooperate to resist relative rotation of the valve members.

[0003]

SUMMARY OF THE INVENTION The present invention provides a new and improved hydraulically assisted power steering apparatus for a motor vehicle. The power steering device includes a manually operable hydraulic control valve assembly that regulates the amount of pressurized hydraulic fluid from a hydraulic pump to a motor device that provides power to assist a driver in driving an automobile. Steering gear. The control valve assembly includes a valve member that is biased and resists rotation with respect to each other, but the valve members rotate with respect to each other and transfer fluid to a vehicle power steering motor. I can send it.

[0004]

SUMMARY OF THE INVENTION A cam in the form of a rocker arm is pivotally connected to one of the valve members, the cam having a portion in contact with the other valve member. When the valve members rotate relative to each other, the rocker arm pivots. The force that can be generated by a spring is
Applied to one of the valve members and the rocker arm to resist pivoting of the rocker arm and relative rotation of the valve members.

In the present invention, the resistance to relative rotation between the valve members changes with the change in the relative angular positions of the inner valve member and the outer valve member. The rocker arm has a cam surface having an outer shape for changing a position where the rocker arm engages with a member that resists pivotal movement of the rocker arm.

In operation of one embodiment of the present invention, the pump supplies fluid to the control valve assembly at a pressure that increases as the speed of the vehicle increases. The fluid pressure supplied by this pump operates the power steering motor. The variable fluid pressure provided by the pump is also used to reduce the relative rotation of the control valve assembly, and thus the resistance to its operation. Fluid pressure from the pump is transmitted to a plurality of piston chambers formed in one of the valve members to reduce resistance to actuation of the control valve assembly.

[0007] In another embodiment of the present invention, the fluid is transferred to a chamber having a rocker arm disposed therein. A relief valve controls the pressure in the chamber to create a force that resists the spring, reducing the resistance to actuation of the control valve assembly.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects of the present invention will become apparent to those skilled in the art from the following detailed description when read in conjunction with the accompanying drawings.

A car steering device 10 (FIG. 1) is used when a driver of a car turns a steering wheel 12.
It acts to turn the wheels (not shown) of a steerable car. Turning the steering handle 12 activates the power steering control valve 14, which is open at the center, to pump fluid from the engine driven pump 18 and the supply conduit 20 to one of the pair of motor conduits 22,24. Motor conduit 2
The high pressure fluid delivered from the supply conduit 20 through either 2 or 24 activates the power steering motor 30 to turn the steerable vehicle wheels. Fluid is sent from the motor 30 to the reservoir 31 through the other one of the motor conduits 22 or 24, the power steering control valve 14, the return conduit 32 and the pressure relief valve 34. A drain conduit 36 directs fluid from a lower portion of the control valve 14 to the reservoir 31.

The control valve 14 has an inner valve member 40 and an outer valve member, ie, a sleeve 42. The outer valve member 42 has a cylindrical shape and encloses the inner valve member 40.
Inner valve member 40 and outer valve member 42 are rotatable with respect to each other and with respect to housing 44 about a common central axis 46.

The inner valve member 40 is formed integrally with a cylindrical input shaft or valve stem 50 connected to the steering handle 12. The outer valve member 42 is connected to the output member 54 by a pin 56. The output member 54 is rotatably supported in the housing 44 by bearings 58 and 60. The output member 54 includes a rack 66
Gear portion 64 meshingly engaged with the toothed portion of
It has. The rack 66 is drivably connected to the power steering motor 30 and the steerable vehicle wheels in a known manner.

The inner valve member 40 and outer member 42 are drivably interconnected through an elastic torsion bar 70 (only a portion of which is shown in FIG. 1). One end of the torsion bar 70 is connected to the input shaft 50 and the torsion bar 70
Is connected to the output member 54. Torsion bar 7
0 flexes (twists) to allow the inner valve member 40 and the outer valve member 42 to rotate relative to each other, and when free, as is well known in the art, the inner valve member 40 and the outer valve member 42. Bias the outer valve member to its initial position.

The control valve 14 is of a type whose center is open. Therefore, when the power steering control valve 14 is in the initial state, that is, in the inactive state, the fluid pressure from the pump 18 causes the piston 7 to move in the power steering motor 30.
8, motor cylinder chambers 74 provided on both sides,
76 is transmitted through motor conduits 22,24. The fluid flow from the pump 18 is introduced into the return conduit 32 and the reservoir 31 by the control valve 14.

When the steering handle 12 is turned and the input shaft 50 rotates, the frictional force between the road surface and the wheels contacting the road surface resists the rotation of the wheels of the car, and the steering between the wheels contacting the ground and the steering handle is performed. Torque is generated in the coupling mechanism. In response to this torque, inner valve member 40 rotates about axis 46 with respect to outer valve member 42. This relative rotation causes the valving edge of the inner valve member 40 to move with respect to the valving edge of the outer valve member 42 to pump high pressure fluid from the pump 18 to the motor conduit 2.
2 or 24 and the fluid is introduced into the reservoir 31 from the other motor conduit.

For example, the inner valve member 40 is replaced by the outer valve member 42
Rotating in one direction with respect to reduces the extent to which the motor conduit 24 communicates with the reservoir 31 and increases the extent to which the motor conduit 24 communicates with the pump 18. As a result, high pressure fluid from pump 18
Is transmitted to This high pressure fluid moves the piston 78 to the right (as viewed in FIG. 1). As the piston 78 moves to the right (as viewed in FIG. 1), fluid evacuated from the chamber 74 is sent to the reservoir 31 through the motor conduit 22, the return conduit 32, and the control valve 14.

When the power steering motor 30 operates, the rack 66 rotates the pinion 64 and the output member 54. Thereby, the outer valve member 42 is connected to the inner valve member 4.
Rotate about zero to return the outer valve member to neutral. When the power steering motor 30 is operated to rotate the steerable vehicle wheels to an extent corresponding to the amount of rotation of the inner valve member 40, the rack 66 moves the outer valve member 42 to its initial position with respect to the inner valve member. Rotate pinion 64 a sufficient distance to move. When this is done, the fluid pressures in the motor cylinder chambers 74, 76 will be equal and motor 30 will stop operating.

The pressurized fluid from the pump 18 is transmitted to an annular central groove 80 formed in the outer valve member 42. The fluid flows to the inside of the outer valve member 42 through a pair of diametrically opposed passages 82. These inner valve members 40
The outer valve member 42 and the outer valve member 42 have the same structure, and are provided on July 7, 1981, entitled "Power Steering Valve and Method of Manufacturing."
aking Same) ", U.S. Pat.
No. 12 cooperates with each other and with the torsion bar 70 in the same manner. However, if desired, the inner valve member 40 and outer valve member 42 can have different configurations.

The inner valve member 40 has a substantially rectangular cross section having rounded corner portions. The rounded corners cooperate with axially extending grooves formed inside outer valve member 42 to control the amount of fluid entering and exiting motor 30. The ends of a pair of diametrically opposed grooves formed inside the outer valve member 42 are connected in fluid communication with an annular outer groove 88 connected to the motor conduit 22. A second pair of diametrically opposed and axially extending grooves formed on the inside of the outer valve member 42 are connected in fluid communication with an annular outer groove 90 formed on the outer valve member; Furthermore, it is connected to a motor conduit 24. A pair of diametrically opposed openings 94 are
It extends radially inward to an axially extending central passage formed in the inner valve member 40. The central passage is connected in fluid communication with the return conduit 32.

An annular force transmitting member, ie, piston 110
Is located in the housing 44 of the power steering control valve, the piston 110 being axially movable with respect to the inner valve member 40 and the outer valve member 42. The annular piston 110 is connected to the inner valve member 40 so as to circumscribe the inner valve member 40 and rotate with the inner valve member 40. However, piston 110 is axially movable with respect to inner valve member 40. Piston 11
0 is the cylindrical outer valve member 4 by the coil spring 112.
2, and the coil spring 112 circumscribes the inner valve member 40, and urges the inner valve member 4.
Rotates with 0.

The downward force applied to the piston 110 by the coil spring 112 applies an annular lower surface 114 of the piston.
(FIG. 2) is pressed against the upper surfaces 120 of the plurality of rocker arms 122. The rocker arm 122 is connected to the inner valve member 4.
It is pivotally connected to zero. It is desirable to provide three rocker arms 122 arranged at equal intervals around the inner valve member 40.

Each of the rocker arms 122 (FIG. 2)
A radial pin 124 extends through the central portion 125 of the rocker arm and is pivotally connected to the inner valve member 40 and the input shaft 50. Bearing 126 pivotally supports rocker arm 122 about pin 124. The rocker arm 122 is pivotable about a radial axis of the inner valve member 40. The axis about which rocker arm 122 pivots passes through and is perpendicular to axis 46 of inner valve member 40 and outer valve member 42.

Each of the rocker arms 122 has a substantially T-shape. To this end, each of the rocker arms 122 has a lower portion 130 that extends parallel to the axis 46 of the inner valve member 40 and the outer valve member 42 when the rocker arms are in the initial position of FIG. . This lower portion 130 of rocker arm 122 extends into a recess 132 formed in the upper end portion of outer valve member 42.
The lower portion 130 of the rocker arm 122 engages a surface 134 that forms a recess 132 in the outer valve portion 42.

The rocker arm 122 includes a lower portion 130
And a pair of side portions 140, 142 extending perpendicularly thereto. These side portions 140, 142 extend from both sides of the central portion 125, so that the rocker arm 122 has a substantially T-shaped shape. When the rocker arm 122 is in the initial position of FIG.
10 is engaged.

As inner valve member 40 rotates with respect to outer valve member 42, the axis about which rocker arm 122 pivots moves with respect to the outer valve member. When this is done, the surface 134 of the recess 132 of the outer valve member 42
Exerts a force on the lower portion 130 of the rocker arm 122. This force causes rocker arm 122 to pivot about pin 124. As the rocker arm pivots about the pin 124, each side portion 14 of the rocker arm
0 or 142 moves upward relative to piston 110 (as shown in FIGS. 1 and 2). Rocker arm 122
The upward force exerted on the piston 110 causes the piston to move upward and compress the spring 112.

As the rocker arm pivots due to rotation of the inner valve member 40 with respect to the outer valve member 42, the spring 112 biases the piston 110 downward (as shown in FIG. 1), causing the rocker arm 122 to pivot. Side part 140 of the
Or 142 (FIG. 2). The side part 14 of the rocker arm 122 is moved by the piston 110 and the spring 112.
A force applied to zero or 142 resists pivoting of the rocker arm. By resisting the pivoting movement of rocker arm 122, piston 110 and spring 112
Resists relative rotation between the inner valve member 40 and the outer valve member 42.

When the inner valve member 40 rotates with respect to the outer valve member 42 in the direction of arrow 144 (FIG. 3), the axis about which the rocker arm 122 pivots is leftward (as viewed in FIG. 3). Go to As a result, the left side surface 134 of the recess 132 formed in the outer valve member 42 applies a force to the lower portion 130 of the rocker arm 122. Lower portion 130 of rocker arm 122 is provided by outer valve member 42.
This force causes the rocker arm to pivot about pin 124 in a counterclockwise direction as shown by arrow 146 in FIG. As rocker arm 122 pivots counterclockwise (FIG. 3), rocker arm side portion 140 moves away from piston 110 and rocker arm side portion 142 moves the piston against the force of spring 112. Bias upward.

According to one feature of the first embodiment of the present invention, the torque required to operate power steering control valve 14 decreases with decreasing vehicle speed. Thus, when the vehicle is slow and the vehicle is stationary, a relatively small torque is required to rotate the inner valve member 40 with respect to the outer valve member 42. When the vehicle is at high speed, more torque is required to rotate inner valve member 40 with respect to outer valve member 42.

The piston 110 (FIG. 1) is connected to the housing 4
4 cooperates with the cylindrical inner surface 150 and the input shaft 50 to form an annular fluid pressure chamber 152 on the axial side of the piston 110 opposite the spring 112. Rocker arm 122 is located within this fluid pressure chamber 152. The fluid pressure chamber 152 includes the inner valve member 4
It is in fluid communication with an axially extending central passage formed at zero and a reservoir 31. The fluid pressure chamber 152
Fluid pressure within biases piston 110 against spring 112 and moves it away from rocker arm 122.

The rotation of the input shaft 50 and the inner valve member 40 relative to the housing 44 and the outer valve member 42 is a torque that is a function of the difference between the fluid pressure applied to the piston 110 and the spring force applied to the piston. Receive resistance. When the input shaft 50 rotates from the initial position, the surface 13 of the recess 132 formed in the outer valve member 42
4 engages rocker arm 122 to pivot rocker arm 122 relative to inner valve member 40. When this occurs, the portion 142 of the rocker arm 122 engages the piston 110 (FIG. 3) to move the piston against the action of the spring 112.

The torque required to pivot rocker arm 122 and move piston 110 away from outer valve member 42 varies as a function of the pure force that urges piston 110 toward outer valve member 42. I do. Therefore, the greater the final force pressing the piston 110 against the rocker arm 122, the greater the input shaft 5
0 and the inner valve member 40 are connected to the output member 54 and the outer valve member 4.
The force required to rotate about 2 is greater. The ultimate force pressing the piston 110 against the rocker arm 122 is equal to the difference between the force applied by the spring 112 and the fluid pressure applied by the fluid in the chamber 152. The greater the fluid pressure applied to the piston 110, the less force must be overcome to rotate the inner valve member 40 with respect to the outer valve member 42.

The pressure relief valve 34 (FIG. 1)
The pressure in 52 is controlled. Electronic control unit, ie ECU1
56 receives the signal from the speed sensor 158 and controls the pressure relief valve 34. EC when car speed decreases
U156 controls the pressure relief valve 34 to
The amount of fluid flowing from 52 to the reservoir 31 is reduced, and the fluid pressure in the chamber 152 is increased. As the speed of the vehicle decreases, the force urging the piston 110 toward the rocker arm 122 decreases and reduces the force applied to the rocker arm that resists pivoting of the rocker arm.
Therefore, when the speed of the vehicle decreases, the resistance to the relative rotation between the inner valve member 40 and the outer valve member 42 also decreases. Electronic control unit 156 and pressure relief valve 34
Has the same structure and mode of operation as the speed responsive control device disclosed in U.S. Pat. No. 4,819,545.

When the steering wheel 12 is turned to rotate the inner valve member 40, the rocker arm 122 applies a force to the piston 110. This force is applied to the chamber 152
The internal fluid pressure is applied to move the piston 110 away from the outer valve member 42. When this occurs, the spring 112 is compressed into a collar 162 which is held stationary in the axial direction with respect to the valve stem 50.

In the embodiment of the present invention shown in FIGS. 1 and 2, the fluid pressure in the chamber
In addition, the resistance given by the rocker arm 122 to the relative rotation between the outer valve members 42 is reduced.
In the embodiment of the present invention shown in FIGS. 4, 5 and 6,
Fluid pressure in the plurality of piston chambers reduces the resistance provided by the rocker arm to relative rotation of the inner and outer valve members. The embodiments of the present invention shown in FIGS. 4, 5 and 6 are substantially similar to the embodiments of the present invention shown in FIGS. 1 and 2, and the same constituent elements use the same reference numerals. To display.

The vehicle power steering device 190 (FIG. 4) is operable to rotate a steerable vehicle wheel (not shown) in contact with the ground when the vehicle driver turns the steering wheel 12. When the speed of the vehicle is equal to or lower than a predetermined speed, turning the steering handle 12 activates the power steering control valve 192 which is opened at the center, and pumps fluid from the pump 18 and the supply conduit 20 to the pair of motor conduits 22, 24. Send to one of them. It is also possible to use similar pumps driven by the engine and controlled by appropriate flow and pressure controls,
Preferably, the pump 18 is driven by an electric motor 200.

The speed at which the pump 18 is driven by the electric motor 200, and thus the flow rate of the pump, is controlled by an electronic controller,
That is, it is set by the ECU 202. The ECU 202
Receives signals from the vehicle speed sensor 204. When the vehicle speed is equal to or lower than a predetermined speed, the ECU 202
The electric motor 200 is operated to drive the pump 18. EC when the vehicle speed exceeds the predetermined speed
U202 stops the motor 200. When the vehicle speed changes from a low speed to a predetermined vehicle speed, the motor 200
Reduces the speed of the pump 18 and thus reduces the flow from the pump.

When the vehicle speed is equal to or lower than a predetermined speed, E
The CU 202 operates the motor 200 to drive the pump 18 at a speed that increases as the speed of the vehicle decreases.
Thus, when the vehicle is stationary or moving very slowly, the motor 200 operates at relatively high speeds with the pump 18.
And a large amount of fluid is supplied by the control valve 192.
As the speed of the vehicle increases, the speed at which motor 200 drives pump 18 decreases, and the amount of fluid supplied to control valve 192 and the steering motor decreases. In the illustrated embodiment of the invention, the ECU 202 calculates the motor 20 by a linear inverse function of the vehicle speed until a predetermined vehicle speed is reached.
0 changes the speed at which the pump 18 is driven. When the vehicle reaches a predetermined speed, the operation of the pump 18 is stopped, and no hydraulic assistance force for steering is applied.

The pressurized fluid is transmitted from the supply conduit 20 to one of the motor conduits 22 or 24 through a control valve 192,
The power steering motor 30 is operated to rotate the steerable vehicle wheels at a speed lower than a predetermined speed. Fluid is transmitted from the motor 30 to the reservoir 31 through the other of the motor conduits 22 or 24 and the return conduit 32. Drain conduit 36 communicates fluid from an upper portion of control valve 192 to reservoir 31.

When the vehicle speed is equal to or higher than the predetermined vehicle speed, the motor 200 is disabled and the pump 18 does not operate. When the pump is stopped, the steerable vehicle wheels are rotated by the action of a manual force transmitted from the steering handle 12 to the pinion gear 64 through the control valve 192. The control valve 192 is of the open-centred type, so that when the wheels of a steerable car are manually turned, fluid can flow through the control valve between the opposing chambers of the power steering motor 30. .

The control valve 192 has an inner valve member 40 and an outer valve member 42. The outer valve member 42 is cylindrical and encloses the inner valve member 40. The inner valve member 40 and the outer valve member 42 are rotatable with respect to each other about a common central axis 46 and with respect to a housing 44.

The inner valve member 40 and the outer valve member 42 are drivably interconnected through an elastic torsion bar 70 (only a portion of which is shown in FIG. 4). One end of the torsion bar 70 is connected to an input shaft 50 formed integrally with the inner valve member 40. The other end of the torsion bar 70 is connected to the output member 54. The output member 54 includes a pin 5
6 is connected to the outer valve member 42. Torsion bar 7
0 flexes to allow relative rotation of the inner valve member 40 and the outer valve member 42 and also attaches the inner and outer valve members to their initial positions, as is well known in the art. Energize.

When the steering shaft 12 is turned to rotate the input shaft 50, the inner valve member 40
6 about the outer valve member 42. Due to this relative rotation, when the speed of the vehicle is equal to or lower than the predetermined speed, the valve action edge of the inner valve member 40 causes the outer valve member 42
And pressurized fluid is introduced from pump 18 into one of motor conduits 22 or 24. Also,
As a result of the relative rotation of the inner valve member 40 and the outer valve member 42, fluid is introduced into the reservoir 31 from the other motor conduit.

When the speed of the vehicle is equal to or less than the predetermined speed, the pressurized fluid from the pump 18 is transmitted to the annular central groove 80 formed in the outer valve member 42. The fluid flows into the outer valve member 42 through a pair of diametrically opposed passages 82. These inner valve member 40 and outer valve member 4
2 have the same structure and can cooperate with each other in the same way as described with reference to the embodiment of FIG. 1 when the speed of the vehicle is below a predetermined speed. However, if desired, these inner and outer valve members 40 and 4
2 may have a different structure.

The piston 110 is located within the power steering control valve housing 44 and is axially movable with respect to the inner valve member 40 and the outer valve member 42. The piston 110 is arranged in a concentric relationship with the input shaft 50 and circumscribes the input shaft 50.
2 urges the outer valve member 42 in the axial direction. The force applied to the piston 110 by the coil spring 112 presses the lower surface 114 (FIG. 5) of the piston 110 against the upper surface 120 of the plurality of rocker arms 122.

The rocker arm 122 is connected to the inner valve member 4.
It is pivotally connected to zero. It is desirable to provide three equally spaced rocker arms 122 around the inner valve member 40. The rocker arm 122 cooperates with the inner valve member 40, the outer valve member 42, the piston 110 and the spring 112 in the same manner as described above with respect to the embodiment of the invention shown in FIGS. Resist relative rotation between the valve member and the outer valve member.

The outer valve member 42 includes a plurality, preferably three, axially extending cylindrical chambers 220. One of the chambers is shown in FIG. An axially extending cylindrical piston 222 engagable with the face 114 of the piston 110 is disposed inside each of the chambers 220. These piston chamber 220 and piston 222 have a common central axis that is parallel to central axis 46 of control valve 192. Each of the axially extending chambers 220 is connected in fluid communication with the pump 18 through a radially extending passage 224 (FIG. 5) and by an annular outer groove 82 formed in the outer valve member 42. I have.

The upper end portion 230 of the piston 222 and the lower end portion 232 of the spring 112 engage both sides of the piston 110. Spring 112 rotates with inner valve member 40. The piston 222 rotates with the outer valve member 42. The piston 222 and piston chamber 220 are preferably located within the outer valve member 42, but these pistons and piston chambers can be located at other locations within the control valve 192 if desired. .

To accommodate the relative rotation of the inner valve member 40 and the outer valve member 42, the piston 110 is
An annular thrust bearing assembly 234 (FIG. 6) is provided. The thrust bearing assembly 234 is disposed between a flat, annular upper thrust plate 236 and a lower thrust plate 238. The upper thrust plate 236 includes a spring 112
Of the upper thrust plate 236
Rotates together with the inner valve member 40. Lower thrust plate 2
The piston 222 is engaged with 38.

When the speed of the vehicle has decreased to a predetermined speed or less, the ECU 202 drives the motor 200 to drive the pump 18 at a speed that increases as the speed of the vehicle decreases. Therefore, the power steering motor 3
The amount of fluid transferred to zero and to the piston chamber 220 increases with decreasing vehicle speed.

When the speed of the vehicle is equal to or less than the predetermined speed, E
The CU 202 operates the motor 200 to operate the pump 18. The pump 18 passes through the passage 224 (FIG. 5).
And the axially extending chamber 22 in the outer valve member 42
Supply pressurized fluid to zero. Fluid pressure within the chamber 220 urges the piston 222 upward, causing the piston 110
To be engaged. When the speed of the vehicle drops below a predetermined speed, the amount of fluid from the pump 18 increases and the
Increase fluid pressure in zero. Further, the pump 18 supplies a pressurized fluid to the power steering motor 30 through the control valve 192.

When the speed of the vehicle is extremely slow, the chamber 22
The fluid pressure in 0 causes the piston 222 to
0 is moved axially upward (as viewed in FIG. 5) to disengage the rocker arm 122. Inner valve member 40
When rotated about the outer valve member 42, the rocker arm 122 pivots but does not engage the piston 110. The only resistance to the initial relative rotation between the inner valve member 40 and the outer valve member 42 is provided by the torsion bar 70. Therefore, when the speed of the vehicle is extremely low, the resistance to the relative rotation between the inner valve member 40 and the outer valve member 42 is minimized.

The operation of the pump 18 is stopped and the inner valve member 4
As the zero and outer valve members 42 rotate relative to each other, the rocker arm 122 pivots and engages the piston 110 if the speed of the vehicle is faster than a significantly lower speed but less than or equal to a predetermined speed. The force exerted by the piston 110 on the rocker arm 122 once again helps the torsion bar 70 resist the relative rotation of the valve members. As the speed of the vehicle increases from a significantly lower speed to a predetermined speed, the fluid pressure in the chamber 220 decreases. Piston 22
The force exerted by piston 2 on piston 110 decreases, increasing the resistance of inner valve member 40 and outer valve member 42 to relative rotation.

When the speed of the vehicle exceeds a predetermined speed, the ECU
202 stops motor 200 and pump 18 does not supply high pressure fluid to control valve 192. In the chamber 220, a piston 222 is urged to move the piston 11
There is no fluid pressure to engage zero. As input shaft 50 rotates from its initial position, surface 134 of recess 132 of rocker arm 122 causes piston 110
To move the piston against the action of the spring 112. By pivoting the rocker arm 122, the piston 110
The torque required to move the outer valve member 42 away from the outer valve member 42 resists relative rotation between the inner valve member 40 and the outer valve member 42.

The ECU 202 stops the motor 200,
When pump 18 does not supply fluid pressure to control valve 192, power steering motor 30 does not serve to assist in turning the steerable vehicle wheels. At this time, the manual force applied to the steering handle 12 is effective in turning the steerable vehicle wheel. This manual force is applied to the torsion bar 70 and the rocker arm 1.
22.

In the embodiment of the invention shown in FIGS. 1, 2 and 3, the torque applied to rocker arm 122 to resist rocker arm pivoting is controlled by the speed of the vehicle. In the embodiment of the present invention shown in FIGS. 7 and 8, the torque applied to the rocker arm 122 changes with a change in the relative angular position between the inner valve member 40 and the outer valve member 42. The embodiments of the present invention shown in FIGS. 7 and 8 are generally the same as the embodiments of the present invention shown in FIGS. 1, 2 and 3, and the same components are denoted by the same reference numerals. Display using.

When the driver turns the steering wheel 12, the vehicle power steering device 290 (FIG. 7) serves to rotate the steerable vehicle wheels (not shown). By turning the steering handle 12, the center of the power steering control valve 29 is opened.
2 is actuated to pump fluid from the engine driven pump 18 and the supply conduit 20 to one of the pair of motor conduits 22,24. Pressurized fluid transmitted from supply conduit 20 through one of motor conduits 22 or 24 activates power steering motor 30 to spin steerable vehicle wheels. Fluid is transmitted from the motor 30 to the reservoir 31 through the power steering control valve 292 and the return conduit 32, other than the motor conduit 22 or 24. Drainage conduit 36 communicates fluid from an upper portion of control valve 292 to reservoir 31.

The control valve 292 has an inner valve member 40 and an outer valve member, that is, a sleeve 42. The outer valve member 42 has a cylindrical shape and encloses the inner valve member 40.
Inner valve member 40 and outer valve member 42 are rotatable with respect to each other and with respect to housing 44 about a common central axis 46.

The inner valve member 40 and the outer valve member 42 are connected to each other via an elastic torsion bar 70 (only a part of which is shown in FIG. 7). One end of the torsion bar 70 is connected to an input shaft 50 formed integrally with the inner valve member 40. The other end of the torsion bar 70 is connected to an output member 54 connected to the outer valve member 42. The torsion bar 70 twists to allow relative rotation between the inner valve member 40 and the outer valve member 42, and the bar 70
When free, as is well known in the art,
The inner and outer valve members are biased back to their initial position.

When the steering handle 12 is turned to rotate the input shaft 50, the inner valve member 40
6 about the outer valve member 42. This relative rotation moves the valving edge of inner valve member 40 with respect to the valving edge of outer valve member 42 and introduces pressurized fluid from pump 18 into one of motor conduits 22 or 24;
The fluid is introduced into the reservoir 31 from the other motor conduit.

The pressurized fluid from the pump 18 is transmitted to an annular central groove 80 formed in the outer valve member 42. The fluid flows into the outer valve member 42 through a pair of diametrically opposed openings 82. These inner valve members 40
And the outer valve member 42 are of identical construction and cooperate with each other as described with respect to the embodiment of FIG. However, these inner valve member 40 and outer valve member 42
Different structures may be used.

The piston 110 is axially urged toward the outer valve member 42 by a coil spring 112 arranged coaxially with the input shaft 50 and circumscribing the input shaft 50. The piston 1 is moved by the coil spring 112.
The downward force applied to 10 urges the lower surface 114 (FIG. 8) of piston 110 against the upper surface 300 of a plurality of rocker arms 302 pivotally connected to inner valve member 40. It is desirable to provide three rocker arms 302 equally spaced about the inner valve member 40.

Each of the rocker arms 302 (FIG. 8)
The inner valve member 40 and the input shaft 50 are
Is pivotally connected to the The bearing 126 is mounted on the pin 12
The rocker arm 302 is supported so as to be pivotable about an axis 4 and about an axis extending perpendicular to the axis 46 of the inner valve member 40 and the outer valve member 42. Each of the rocker arms 302 includes a first valve member 40
And the lower portion 13 extending parallel to the axis 46 of the second valve member 42 and reaching the recess 132 of the outer valve member 42
0 is provided. The lower part 1 of the rocker arm 302
30 is the surface 13 forming the recess 132 of the outer valve member 42
4 is engaged.

The rocker arm 302 is connected to the lower part 13.
A pair of side portions 304, 306 extending perpendicular to zero
It has. These side portions 304, 306 extend from both sides of the central portion 308, so that the rocker arm 302 has a T-shape. When the inner valve member 40 and the outer valve member 42 rotate relative to each other, the rocker arm 302 pivots about the pin 124. One of the side portions 304 or 306 is the piston 11
0 to move the piston axially away from the outer valve member 42 against the force of the spring 112. The spring 112 and the piston 110 apply a torque to the rocker arm 302 to resist pivotal movement of the rocker arm and to resist relative rotation between the inner valve member 40 and the outer valve member 42.

Each of the surfaces 300 of the rocker arm 302 has a predetermined outer shape. As a result of the outer shape of this surface 300, the location where the piston 110 engages the rocker arm 302 is:
As the relative angular position between the inner valve member 40 and the outer valve member 42 changes, the distance fluctuates along the surface 300.
As a result of the change in the contact point between the piston 110 and the rocker arm 302, the torque applied to the rocker arm by the piston also changes. The force applied to the rocker arm 302 by the piston 110 is constant, while the length of the moment arm of the force applied to the rocker arm varies. For this reason, the torque applied to the rocker arm 302 changes depending on the relative angular positions of the inner valve member 40 and the outer valve member 42.

As the input shaft 50 rotates and the inner valve member 40 rotates with respect to the outer valve member 42, the rocker arm 302 pivots with respect to the inner valve member. The pivot amount of the rocker arm 302 depends on the relative rotation amount between the inner valve member 40 and the outer valve member 42. Piston 11
The point of contact between the zero and the rocker arm 302, and therefore the moment arm of the force applied to the rocker arm, depends on the amount by which the rocker arm pivots with respect to the inner valve member 40. In this way, the resistance of the piston 110, the spring 112, and the rocker arm 302 to the relative rotation between the inner valve member 40 and the outer valve member 42 is
It changes with a change in the relative angular position between the inner valve member and the outer valve member.

From the above description, those skilled in the art will recognize their modifications,
Changes and modifications will be recognized. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.

[Brief description of the drawings]

FIG. 1 is a schematic view of a first embodiment of a power steering apparatus showing a power steering control valve in a sectional view.

FIG. 2 is an enlarged view of a portion of FIG. 1 showing a relationship between inner and outer valve members and a rocker arm when the valve members are in an inoperative state.

FIG. 3 shows the relationship between the inner and outer valve members and the rocker arm when the valve members rotate relative to each other.
FIG.

FIG. 4 is a schematic view similar to FIG. 1 of a second embodiment of the power steering apparatus, showing the second power steering control valve in a sectional view.

FIG. 5 is an enlarged cutaway view of a part of FIG. 4;

FIG. 6 is an enlarged partial sectional view of a part of FIG. 4;

FIG. 7 is a schematic view similar to FIG. 1 of a third embodiment of the power steering apparatus, showing a third power steering control valve in a sectional view.

FIG. 8 is an enlarged view of a part of FIG. 7 showing a second embodiment of the rocker arm.

[Explanation of symbols]

Reference Signs List 10 Steering device 12 Steering handle 14 Power steering control valve 18 Motor driven pump 20 Supply conduit 22, 24 Motor conduit 30 Power steering motor 31 Reservoir 32 Return conduit 34 Pressure relief valve 36 Drain conduit 40 Inner valve member 42 Outer valve member 44 Housing Reference Signs List 50 valve stem / input shaft 54 output member 56 pin 64 pinion gear portion 66 rack 70 torsion bar 74, 76 motor cylinder chamber 78 piston 88, 90 outer groove 94 opening 110 piston 112 coil spring 114 lower surface 120 upper surface 122 rocker arm 124 pin 126 Bearing 150 Inner surface of housing 152 Liquid pressure chamber 156 Electronic control unit 158 Speed sensor 162 Color

Claims (39)

(57) [Claims] 1. A vehicle steering system comprising: first and second valve members that rotate with respect to each other and deliver fluid to a vehicle power steering motor; and are pivotally connected to the first valve member. A rocker arm that is pivotable with respect to the first valve member by the second valve member when the first and second valve members rotate relative to each other. Applying a force to the rocker arm to resist pivoting of the rocker arm with respect to the first valve member by the second valve member, whereby the first valve member and the second Means for resisting relative rotation between the valve members. 2. The steering apparatus according to claim 1, further comprising means for changing a resistance of the rocker arm to the pivoting operation of the first valve member. 3. The steering apparatus according to claim 1, wherein the means for applying a force to the rocker arm engages the rocker arm and is perpendicular to a pivot axis of the rocker arm. A steering device comprising: a force transmitting member movable with respect to an arm; and means for urging the force transmitting member toward the rocker arm. 4. The steering apparatus according to claim 3, wherein said means for urging said force transmitting member toward said rocker arm comprises a spring. 5. The steering device according to claim 1, wherein the first and second valve members are substantially cylindrical, and the second valve member surrounds the first valve member. And a steering device. 6. The steering device according to claim 1, wherein said second valve member comprises surface means defining a recess, and said rocker arm extends into said recess and is connected to said surface means. An engaging portion, capable of transmitting a force between the second valve member and the rocker arm when the first valve member and the second valve member rotate relative to each other. A steering device, comprising: 7. The steering apparatus according to claim 1, wherein the first valve member and the second valve member rotate relative to each other, so that the pivot axis of the rocker arm becomes the second valve. Moving with respect to a member, the rocker arm comprising a first portion to which a force is applied by the second valve member, wherein the rocker arm is moved relative to the second valve member when the rocker arm moves with respect to the second valve member. Pivoting in a first direction about the rocker arm, wherein the rocker arm is a second portion extending in a direction perpendicular to the first portion, the means for applying a force to the rocker arm, A steering device comprising: a second portion to which a force for pivoting the rocker in a second direction about a pivot axis thereof is applied. 8. The steering apparatus according to claim 1, further comprising means for reducing a resistance to relative rotation between the first and second valve members when the speed of the vehicle decreases. A steering device characterized by the above-mentioned. 9. The steering apparatus according to claim 8, wherein the means for applying a force to the rocker arm is a force transmitting member engageable with the rocker arm, and the force transmitting member is capable of engaging the rocker arm with respect to a pivot axis of the rocker arm. A force transmitting member movable with respect to the rocker arm in a direction perpendicular to the rocker arm, and means for applying a first force to the force transmitting member to bias the force transmitting member toward the rocker arm. Characteristic steering device. 10. The steering apparatus according to claim 9, further comprising: means for applying a second force to the force transmitting member to urge the force transmitting member in a direction away from the rocker arm. And a steering device. 11. The steering device according to claim 10, further comprising: means for increasing a second force applied to the force transmitting member when the speed of the vehicle decreases. 12. The steering apparatus according to claim 10, wherein the means for applying the second force to the force transmitting member comprises a surface means forming a chamber for holding a pressurized fluid, A steering device, wherein a fluid pressure acts on the force transmitting member to urge the force transmitting member in a direction away from the rocker arm. 13. The steering apparatus according to claim 12, wherein when the speed of the vehicle decreases, the fluid pressure in the chamber is increased, so that the force transmitting member is moved away from the rocker arm. A steering device, further comprising means for increasing a biasing force. 14. The steering apparatus according to claim 1, further comprising means for disabling the means for applying a force to the rocker arm when the speed of the vehicle is equal to or lower than a predetermined speed. And a steering device. 15. The steering device according to claim 14, wherein the means for applying a force to the rocker arm comprises:
A force transmitting member engageable with the rocker arm,
A force transmitting member movable relative to the rocker arm in a direction perpendicular to the pivot axis of the rocker arm, and applying a first force to the force transmitting member to apply the force transmitting member toward the rocker arm. A steering device. 16. The steering apparatus according to claim 15, wherein the means for disabling the means for applying a force to the rocker arm applies a second force to the force transmitting member to transmit the force. A steering device comprising means for urging a member away from the rocker arm. 17. The steering apparatus according to claim 16, wherein the means for applying a second force to the force transmitting member includes a second force transmitting member engageable with the first force transmitting member. Surface means for forming a chamber for holding a pressurized fluid, wherein the fluid pressure in the chamber acts on a part of the second force transmitting member, causing the second force transmitting member to move to the first force transmitting member. A steering device, wherein the first force transmitting member is moved in a direction away from the rocker arm, while being biased toward the force transmitting member. 18. The steering apparatus according to claim 14, wherein the means for disabling the means for applying a force to the rocker arm includes a means for disengaging the rocker arm when a vehicle speed is equal to or higher than a predetermined speed. A pump for supplying fluid pressure to a chamber in the means for disabling the means for applying force and a pump for supplying fluid pressure to the chamber when the speed of the vehicle exceeds a predetermined speed; A steering device. 19. The steering device according to claim 1, wherein the means for applying a force to the rocker arm includes a first and a second valve member which rotate while the valve members rotate relative to each other. A steering device, comprising: means for changing a position where a force is applied to the rocker arm when a relative angular position changes. 20. The steering device according to claim 1, wherein the means for applying a force to the rocker arm comprises a force transmitting member, wherein the force transmitting member comprises the rocker arm.
Surface means engageable with the upper surface means, the force transmitting member being movable with respect to the rocker arm in a direction perpendicular to the pivot axis of the rocker arm;
The force transmitting member and the surface means of the rocker arm define a position where the force transmitting member engages with the rocker arm while the first valve member and the second valve member rotate relative to each other. A steering device having an outer shape to be changed. 21. The steering apparatus according to claim 20, wherein the surface means of the rocker arm is configured to rotate the first and second valve members while the first and second valve members rotate relative to each other. A steering device having an outer shape that changes a position where the force transmitting member engages with the rocker arm when a relative angular position of the valve member changes. 22. The steering device according to claim 1, wherein the rocker arm extends centrally from the central portion in a first direction and pivotally connected to the first valve member. A first portion cooperating with said second valve member, and said means for applying a force to said rocker arm, from said central portion in a second direction perpendicular to said first direction. A second portion extending from the central portion, adjacent the means for applying a force to the rocker arm, and extending from the central portion in a third direction perpendicular to the first direction. The rocker arm, when the first and second valve members rotate relative to one another in one direction and press the second portion of the rocker arm against the means for applying a force to the rocker arm, Rocker arm said first Moving the third portion of the rocker arm away from the means for applying a force to the rocker arm, the rocker arm being pivotable with respect to the first valve member by the action of a force applied to the portion; However, when the first valve member and the second valve member rotate relative to each other in another direction opposite to the one direction in which the valve members rotate relative to each other, the first By the action of the force applied to the part,
The third portion of the rocker arm is pivotable with respect to the first valve member and presses the third portion of the rocker arm against the means for applying a force to the rocker arm, and the second portion of the rocker arm is pressed against the rocker arm. A steering device for moving in a direction away from said means for applying a force. 23. A steering device according to claim 22, wherein said pin means extends outwardly from said first valve member to said central portion of said rocker arm, and said center of said pin means and said rocker arm. And a bearing means for supporting the rocker arm so as to be pivotable with respect to the pin means. 24. The steering device according to claim 22, wherein the second valve member includes surface means for forming a recess in the second valve member, and the first portion of the rocker arm. Extend into the recess, wherein the surface means is configured to rotate the first valve member and the second valve member relative to each other in one direction. Operable to apply a force to a side portion of the rocker arm when the first and second valve members rotate relative to each other in opposite directions. A steering device operable to apply a force to a side portion of the steering wheel. 25. The steering device according to claim 1, wherein the second valve member extends parallel to an axis about which the first and second valve members rotate with respect to each other. And elongate piston disposed at least partially within the elongate chamber in the second valve member, the elongate means defining an elongate chamber having a longitudinal axis offset from the axis. And a means for transmitting fluid pressure to one end of the chamber and biasing the piston toward the means for applying a force to the rocker arm. 26. A vehicle steering system comprising: first and second valve members that rotate with respect to each other and deliver fluid to a vehicle power steering motor; A force transmitting unit that resists rotation, and a speed response unit that changes a resistance applied by the force transmitting unit to a relative operation between the first and second valve members, The speed response means includes a plurality of pistons disposed in a chamber formed in the second valve member, wherein the chamber and the piston include:
A central axis parallel to and spaced apart from the axis about which the first and second valve members rotate with respect to each other; and as a function of vehicle speed. A steering device for transmitting varying fluid pressure to the chamber, the device comprising means for biasing the piston to the force transmitting means with a force that varies as a function of vehicle speed. 27. The steering device according to claim 26, wherein the force transmitting means includes a plurality of pivot members connected to the first valve member and capable of pivoting with respect to the valve member. The moving member is pivoted by the second valve member when the first valve member and the second valve member rotate relative to each other, and further, the moving member is pivoted by the second valve member. Means for applying a force to the pivot member to resist pivoting, wherein the piston applies a force to the pivot member to reduce the force applied to the pivot member by the second valve member. A steering device having an end portion for applying a force to said means. 28. The steering device according to claim 26, wherein the force transmitting means has a plurality of recesses in the second valve member at a position in the second valve member separated from the chamber. Surrounding the first valve member;
An annular force transmitting member, and a plurality of force transmitting elements extending into the recess and disposed in engagement with the annular force transmitting member, wherein the force transmitting element is the first valve. When the member and the second valve member rotate relative to each other, the steering device is operable to transmit a force between the second valve member and the annular force transmitting member. 29. The steering device according to claim 28, wherein the force transmitting means further includes means for urging the annular force transmitting member toward the force transmitting element, and wherein the piston includes the annular force transmitting member. A steering device capable of transmitting a force to the force transmitting member and biasing the annular force transmitting member in a direction away from the force transmitting element. 30. The steering device according to claim 26, wherein said force transmitting means each extend from said central portion in a first direction and connected to said second valve member. A first portion, a second portion extending from the central portion in a second direction perpendicular to the first direction, and in a third direction perpendicular to the first direction. And a third portion extending from the central portion, wherein each of the force transmitting elements is such that the first valve member and the second valve member relatively move in one direction. When rotating, the force transmitting element is movable in one direction with respect to the first valve member by an action of a force applied to the first portion of each of the force transmitting elements. The first valve member and the second valve member in another direction opposite to the relative rotational direction of When the valve members to each other is relatively rotated by the action of force applied to said first portion of said rocker arm, a steering device, characterized in that the movable in the movement direction opposite to another direction of the. 31. The steering device according to claim 30, wherein a central portion of each of the force transmitting elements is pivotally connected to the first valve member. 32. A vehicle steering system comprising: a first and a second valve member rotatable with respect to each other; and the first and second valve members rotating relative to each other when the first and second valve members rotate relative to each other. A plurality of force transmitting elements movable with respect to the valve member and the second valve member; and resisting movement of the plurality of force transmitting elements and relative rotation between the first and second valve members. Means for applying a force to the plurality of force transmitting elements, wherein each of the plurality of force transmitting elements has a central portion,
A first portion extending from the central portion in a first direction and connected to the second valve member, and a first portion extending from the central portion in a second direction perpendicular to the first direction. A second portion, a second portion disposed adjacent to the element for applying a force to the force transmitting element, and extending from the central portion in a third direction perpendicular to the first direction. A third portion disposed adjacent to said means for applying a force to said force transmitting element, wherein each of said force transmitting elements comprises said first valve member and When the second valve members rotate relative to each other in one direction, the force transmitting element moves with respect to the first valve member by the action of a force applied to the first portion of each of the force transmitting elements, and Pressing the second portion of each of the elements against the means for applying a force to each of the force transmitting elements Moving the third portion of each of the force transmitting elements away from the means for applying a force to each of the force transmitting elements, wherein each of the force transmitting elements is positioned relative to the valve member. The action of a force applied to the first portion of each of the force transmitting elements when the first and second valve members rotate relative to each other in another direction opposite to the direction of rotation. Is movable with respect to the first valve member and presses the third portion of each of the force transmitting elements against the means for applying a force to the force transmitting element, and the second portion of each of the force transmitting elements The steering device is moved in a direction away from the means for applying a force to the force transmitting element. 33. The steering device according to claim 33, wherein said central portion of each of said force transmitting elements is pivotally connected to said first valve member. 34. The steering device according to claim 32, further comprising speed response means for changing a force applied to the plurality of force transmitting elements by the means for applying a force to the plurality of force transmitting elements, The speed response means extends parallel to an axis which is the center when the first valve member and the second valve member rotate relative to each other, and defines a central axis arranged at a distance from the axis. A plurality of pistons disposed in the chamber having a fluid pressure that varies as a function of vehicle speed to the chamber and forcing the plurality of force transmitting elements with a force that varies as a function of vehicle speed. Means for biasing the piston toward the means. 35. A first and a second valve member for a vehicle steering device forming valve means for rotating with respect to each other and delivering fluid to a vehicle power steering motor ; And a plurality of force transmitting elements connected to the second valve member, when the first valve member and the second valve member rotate relative to each other, the first valve member and the second A plurality of force transmitting elements movable with respect to the valve member; force applying means for applying a force to the force transmitting element to resist relative rotation between the first valve member and the second valve member; Means for supplying fluid to the valve means at a pressure which decreases with increasing speed; means for transmitting fluid from the valve means to the power steering motor of the vehicle at a pressure which decreases with increasing speed of the vehicle. And the fluid pressure supplied to the valve means is low. When the speed of the vehicle increases, the force applied to the plurality of force transmitting elements by the force applying means is increased, and when the speed of the vehicle increases, the first valve member and the second valve member are connected to each other. Means for increasing the resistance to relative rotation. 36. The steering device according to claim 35, wherein the force applying means includes an annular member, and means for pressing the annular member against the force transmitting element, and the fluid supplied to the valve means. As the pressure decreases and the speed of the vehicle increases, the means for increasing the force applied by the force applying means to the plurality of force transmitting elements changes with a variation in the fluid pressure supplied to the valve means. A steering device, comprising: chamber means for holding a fluid under pressure, the chamber means being operable to provide a force to bias the annular member away from the force transmitting element. 37. The steering device according to claim 35, wherein the force applying means includes: an annular member; and means for pressing the annular member against the force transmitting element, wherein the fluid supplied to the valve means is provided. As the pressure decreases and the speed of the vehicle increases, the means for increasing the force applied by the force applying means to the plurality of force transmitting elements changes with a variation in the fluid pressure supplied to the valve means. A steering device comprising: a plurality of pistons biased toward said annular member by fluid pressure. 38. The steering device according to claim 35, wherein when the fluid pressure supplied to the valve means decreases and the speed of the vehicle increases, the force applying means applies the force to the plurality of force transmitting elements. The means for increasing a force comprises a plurality of pistons disposed in a chamber in the second valve member, wherein the chamber and the piston rotate the first and second valve members with respect to each other. A steering device having a central axis extending in parallel with an axis serving as a center when performing the operation and spaced apart from the axis. 39. The steering device according to claim 38, wherein the force transmitting element is pivotally connected to the first valve member, and the first and second valve members rotate. A steering device which is pivotable with respect to the first valve member about an axis extending at right angles to an axis which becomes a center when the first valve member is operated.