JP2706788B2 - Control valve - Google Patents

Description

Description of the Invention [Object of the Invention] (Field of Industrial Application) The present invention relates to a control valve for controlling a generated pressure by a differential value of a pilot pressure.

(Prior Art) In four-wheel steering, it has been found that controlling the steering angles of the front wheels and the rear wheels enhances the motion characteristics during turning.

That is, at the start of steering, the rear wheel is momentarily shifted to the opposite phase, and the steering angle of the front wheel is increased to balance the yaw rate and the lateral acceleration. Thereby, the rising of the rotational motion of the vehicle is improved. Then, the next moment, returning to steady four-wheel in-phase steering,
The vehicle is able to turn along the trajectory aimed at while keeping the sideslip angle at zero.

It is considered that such four-wheel steering is performed using highly reliable hydraulic control. To achieve this,
It is conceivable that the hydraulic pressure is controlled by a control valve and input to the hydraulic front wheel steering mechanism and the rear wheel steering mechanism.

To this end, the time change rate of the steering angle velocity, which is the differential term of the steering angle, or the power steering pressure, which is equivalent to the same, and the vehicle speed (because the steering angle speed and the absolute value of the time change rate are different even at the same handle angle) It is necessary to generate hydraulic pressure according to the two conditions.

(Problems to be Solved by the Invention) However, there is no control valve that outputs a hydraulic pressure having such complicated characteristics, which has been a bottleneck for realization.

The present invention has been made in view of such circumstances, and a purpose thereof is to control an input pressure by a differential value of one pilot pressure and another pilot pressure. It is to provide a valve.

[Means for Solving the Problems] To achieve the above object, a control valve according to the present invention includes a valve body, a spool slidably provided in the valve body, and an outer periphery of the spool. A pair of pressure receiving chambers provided with the sleeve end facing the end face side of the sleeve and filled with a fluid, and a first end provided on the spool end provided on the valve body. A first pilot input port for inputting a pilot pressure, and a first pilot input port connected between the pressure receiving chambers for relatively displacing the spool and the sleeve in accordance with the pressure of the pilot pressure input from the first pilot input port. A flow path, a second pilot input port provided in the valve body for inputting a second pilot pressure, and the second pilot input port interposed in the flow path. A throttle device that receives a second pilot pressure input from a port and that can change a throttle amount that changes a relative displacement amount of the spool and the sleeve in accordance with the pressure; a fluid inlet port provided in the valve body; An opening / closing passage provided on the spool and the sleeve for varying the pressure of the fluid input from the fluid inlet port in accordance with the relative displacement between the spool and the sleeve; and a fluid provided on the valve body for varying the pressure. A fluid outlet port is provided.

(Operation) According to the control valve of the present invention, when the first pilot pressure is applied from the first pilot input port,
The spool slides by an amount proportional to the first pilot pressure. Then, at this time, the sleeve relatively shifts with respect to the spool in accordance with the differential pressure generated on both sides of the expansion device which varies according to the second pilot pressure.
Then, the opening degree of the opening / closing passage is determined according to the relative displacement. Thereby, the pressure of the fluid input from the fluid inlet port is controlled to a pressure corresponding to the two inputs of the differential value of the first pilot pressure and the second pilot pressure, and this is output from the fluid output port to the outside. Go.

(Embodiment) Hereinafter, the present invention will be described based on an embodiment shown in FIGS. 1 to 19. FIG. 15 shows a four-wheel steering device for a vehicle to which the present invention is applied, wherein 1a and 1b are left and right front wheels. The front wheels 1a and 1b are rotatably supported by knuckles 2a and 2b which are supported so as to be swingable in a horizontal direction with respect to a vehicle body (not shown). Knuckles 2a, 2b are tie lots 3a,
For example, it is connected via a 3b to a vehicle speed-sensitive power steering 6 formed by combining a rack 4 and a pinion 5. That is, the power steering 6 includes a steering gear assembly 9 having a rack 4, a pinion 5, a rotary valve 7, and a torsion bar 8, and a power cylinder device 10 for steering connected to the rotary valve 7.
(Piston 12 connected to rack 4 in power cylinder 11
And an engine-driven oil pump 13 (for power steering) that supplies hydraulic pressure to the rotary valve 7. And the power cylinder device 10
The piston rods 12a, 12b on both sides of the piston 12 are connected to the tie rods 3a, 3b.

Further, a steering wheel 17 is connected to a valve input shaft 7a and a torsion bar 8 of the rotary valve 7 connected to the pinion 5, which are input portions of the steering gear assembly 9, via a phase advance mechanism 14, an intermediate joint 15, and a column shaft 16 to be described later. Are connected. Thus, when the steering wheel 17 is operated, the rack 4 is driven in the same direction as the steering wheel 17. And at the same time, the left ventricle 1 configured on both sides of the piston 12
8, a power steering pressure generated by the oil pump 13 is supplied to the right chamber 19 through the rotary valve 7, so that the steering force of the steering wheel 17 can be assisted. In addition,
As the oil pump 13, a pump whose discharge flow rate decreases as the rotation speed of the engine 20 increases from a certain region is used.

Here, the phase advance mechanism 14 will be described. The phase advance mechanism 14 is provided with two sets of planetary gear mechanisms 21 and 22 and a control valve 23 on the steering gear assembly 9 as shown in detail in FIGS. Is provided.

In detail, 37 is a case installed on the upper end of the case 9a of the steering gear assembly 9, and 37a is the case 3
7 is a screw-type cap for closing the upper opening. The case 37 and the cap 37a are fixed to the case 9a by bolts 35 penetrating therethrough and nuts 36 screwed to bolt ends, and constitute a body of the phase advance mechanism 14.
On the upper side in the case 37, the input shaft 24 is rotatably provided coaxially with the valve input shaft 7a. 24a is a bearing that rotatably supports the input shaft 24. A sun gear 25 is provided integrally with a lower outer periphery of the input shaft 24. Around this sun gear 25, a ring gear 26 supported on the case 37 side is provided. Further, between the ring gear 26 and the sun gear 25, four sets of planetary gears 27 meshing with the gears are provided on both sides, and constitute the first stage planetary gear mechanism 21. On the upper part of the input shaft 24 protruding from the cap 37a,
Are linked.

The end of the valve input shaft 24 projects upward from the upper end opening of the case 9a. And this case
A sun gear 28 having the same specifications as the first-stage planetary gear 21 is integrally provided on the outer periphery of the end of the valve input shaft 24 that enters the inside 37. A ring gear 29 having the same specifications as the first stage is provided in a case 37 around the sun gear 28. The first stage planetary gear 27 is provided between the ring gear 29 and the sun gear 28 via a shaft 30.
There are provided four rotatable planetary gears 31 which are coaxial with the planetary gear mechanism 22 and constitute a second stage planetary gear mechanism 22. In addition, the planetary gear 27 and the planetary gear 31
A holder 32 for holding 30 and a holder 33 for gear regulation provided at the end of the shaft are supported so as to be movable in the circumferential direction around the axis of the valve input shaft 24.

An adjuster 38 for regulating the vertical movement of the bearing 24a is provided on the cap 37a, and the planetary gear mechanisms 21 and 22 are provided.
Are assembled to the steering gear assembly 9 in a predetermined manner. Numeral 39 is a seal member, numeral 40 is a nut for preventing the adjuster 38 from loosening, and numeral 41 is a spacer for restricting the vertical movement of the ring gears 26, 29.

The distal end of the valve input shaft 7a is inserted into a concave portion 43 provided at the shaft end of the input shaft 24. The end of the torsion bar 8 is connected to the insertion end of the valve input shaft 7a by a pin 44, and the steering wheel 1 is fixed with the ring gears 26 and 29 fixed.
When the steering wheel 7 is steered, the steering angle of the steering wheel 17 can be transmitted to the rotary valve 7 and the torsion bar 8 at the same ratio through the first and second stage planetary gear mechanisms 21 and 22. However, between the insertion end of the valve input shaft 7a and the concave portion 43, a metal bush 45 for preventing rattling in the circumferential direction is interposed.

The first-stage planetary gear mechanism 21 is provided with a safety device 46 for preventing an excessive torque from the steering wheel 17 from entering. Specifically, the safety device 46 has a concave portion 47 on the outer peripheral surface of the ring gear 26. Also, on the case 37 side, a pin part 48 and a pin part 4
There is provided a set screw composed of a spring 49 and an adapter component 50 for urging the connector 8 in the fitting direction. And
With this structure, the rotation of the ring gear 26 in the rotational direction is restricted by the concave and convex fitting, and when an excessive steering force exceeding the preload from the steering wheel 17 enters the ring gear 29, the concave and convex fitting is released and the ring gear 26 is released. Can be rotated to protect the planetary gear mechanisms 21 and 22 from excessive torque. Although not shown, a stopper portion formed by fitting a stepped portion is provided at the end of the input shaft and the end of the valve input shaft which are in the fitted state. When they rotate, they come into contact with each other so that the steering force from the steering wheel 17 is directly transmitted from the input shaft 24 to the valve input shaft 16.

The control valve 23 for phase advance is mounted on a case 37 on which the planetary gear mechanisms 21 and 22 are mounted.

In other words, regarding the control valve 23, reference numeral 51 denotes an elongated valve body integrally provided in a case portion adjacent to the ring gear 29 along a direction perpendicular to the center of the planetary gear mechanism 22. In the valve body 51, the ring gear 29
A substantially cylindrical valve chamber 52 is formed along a direction perpendicular to the axis of the valve chamber 52. A spool 53 is provided in the valve chamber 52. One end of the spool 53 is slidably supported by a plug 54 attached to an end of the valve chamber 52, and the other end is slidably supported by a plug 56 attached to the other end of the valve chamber 52 via an adapter 55. Supported. Then, each shaft end face of the spool 53 faces the hole 54a, 56a of the plug 54, 56. A spring chamber 55a is formed inside the adapter 55. And, in this spring chamber 55a, a spring spanned between a washer 56a slidably fitted to the small diameter portion 53a on the outer periphery of the end of the spool 53 and a snap ring 57 fixed to the end of the small diameter portion 53a. The spool 58 is accommodated therein, and the spool 53 is positioned by the spring 58. 59 is a plug
Nuts for locking the 54, 56 and adapter 56.

A plate-shaped lever 60 is provided on the outer periphery of the spool 53 so as to movably penetrate the shaft of the spool 53. The lever 60 is arranged on a line that intersects the axis of the ring gear 29 at right angles. An arc portion formed at the end of the lever 60 on the ring gear 29 side is engaged with a groove portion 62 formed on the outer peripheral surface of the ring gear 29 through a through hole 61 formed in the valve body portion and the case portion. ing. Further, the arc portion formed at the remaining narrow end of the lever 60 is rotatable in the groove 65 of the plate 64 provided on the inner bottom surface of the adapter 63 mounted on the valve chamber 52 so as to cover the end. The entire lever is rotatable along the axis of the spool 53 with the end on the plate 64 side as a fulcrum. In addition, 66 is an adapter
63 is a locking nut and 67 is a corrugated washer interposed between the plate 64 and the inner bottom surface of the adapter 63.

A collar 68 is slidably fitted on the outer periphery of the spool portion on the plug 54 side, and a sleeve 69 is slidably fitted on the outer periphery of the spool portion on the plug 56 side with the lever 60 interposed therebetween. The collar 68 and the sleeve 69 are provided with a spring 7 provided between the outer end thereof and the plug 54 and the adapter 55.
By the elastic force (preload) of 0a and 70b, the lever 60 is pressed on both sides of the lever 60, and the three parts including the lever 60 are positioned on the spool 53. On the outer peripheral surface of the spool 53 covered with the sleeve 69, two inflow-side chambers 71, 72 each formed of an annular groove are provided in parallel. On the other hand, chambers 71, 7
Two outflow-side chambers 73 to 75 each composed of a groove are provided at the boundary portion of No. 2. The chamber 71 communicates with a pressure receiving chamber 77 which is formed between the collar 68 and the plug 54 and also serves as a spring chamber via a passage 76 provided inside the spool 53. Further, the chamber 72 communicates with a pressure receiving chamber 79 which is formed between the sleeve 69 and the adapter 55 and also serves as a spring chamber via a passage 78 similarly provided inside the spool 53.
The center chamber 74 on the outflow side is connected to the discharge section of the oil pump 13 via a port 80 provided in the valve body 51. The remaining chambers 73 and 75 are provided by ports 81 provided in the valve body 51.
Through the inlet port (not shown) of the rotary valve 7 of the steering gear assembly 9 to hold the ring gear 29 at a predetermined position by using the hydraulic pressure generated by the oil pump 13 or to input the steering angle. And a follow-up servo valve (spool valve) that can increase the number of motors. That is, since the oil of the oil pump 13 flows into the pressure receiving chambers 77 and 79 through the passages 76 and 78, when the sleeve 69 is displaced by the steering reaction force from the second-stage ring gear 29, the chambers 71 and 72 and the chamber 71 From the opening and closing with 73-75, at the same time as a lot of oil flows into the displaced pressure receiving chamber side,
A large amount of oil flows out from the remaining pressure receiving chamber side, and the displaced sleeve 69 is returned to the original position in order to return the ring gear 29 to the original state. Also plug 54 and plug 56
When the force for displacing the spool 53 is applied from above, the sleeve 69 moves in accordance with the displacement of the spool 53, and rotates the lever 60 to rotate the ring gear 29 to the additional side (steering gear). Ratio variable).

On the other hand, 82a and 82b are left and right rear wheels. The rear wheels 82a, 82b
It is supported by a double wishbone type rear wheel suspension with a toe control mechanism. That is, the rear wheel suspension is
A pair of upper and lower lateral arms composed of 84 and a lower arm 85 are provided, and an arm formed by connecting a toe control arm 86 and a trailing arm 87 by an intermediate joint 88 is connected. The rear wheels 82a and 82b are supported on the arm ends via wheel supports (not shown). The intermediate joint 88 includes a pivot shaft 89 such as a pin whose rotation axis is set substantially in the vertical direction, and has a structure capable of steering the rear wheels 82a and 82b according to the displacement of the intermediate joint point.

Further, a double rear power cylinder 90 is provided on the cross member 83 so as to connect the left and right pivot shafts 89, 89 of the rear wheel suspension. That is, the rear power cylinder 90 includes a cylinder 9 having a large-diameter cylinder chamber 91 formed in the center and a pair of small-diameter cylinder chambers 92a and 92b formed on both sides.
4, a piston part 95a having a diameter corresponding to the cylinder chamber 91 is provided at the center.
And a piston 95 having a piston portion 95b on both sides having a diameter corresponding to the cylinder chambers 92a and 92b is slidably provided.
In addition, piston rods 96a, 96
It is constructed by connecting b. A left chamber 97a and a right chamber 97b that receive an output for the same phase are formed in a portion where the cross-sectional area of the cylinder chamber 91 partitioned by the piston portion 95a is large. Room 97
The cross-sectional areas of the cylinder chambers 92a and 92b, which are lined with the cylinder chambers a and 97b, receive a phase output in a small space. This cylinder 94
However, it is fixed to the cross member 83 with the axial direction determined in the left-right direction. Then, the left piston rod 96a is connected to the pivot shaft 39 of the left intermediate joint 38, and the receiving piston rod 96b is connected to the pivot shaft 39 of the right intermediate joint 38, after the movement of the piston 95. The wheels 82a and 82b can be steered.

The left chamber 97a and the right chamber 97 of the rear power cylinder 90
b is connected to an in-phase control valve 98 via an oil flow passage 99, and the cylinder chambers 92a and 92b of the rear power cylinder 90 have a phase control valve 100 which is a main part of the present invention.
Are connected via oil passages 101a and 101b.

As the in-phase control valve 98, a spool valve as shown in FIG. 16 is used. Specifically, the spool valve has a spool 221 whose both ends are urged by a pair of springs 220 in a cylindrical case 102. Two annular grooves 222 and 223 are provided side by side on the outer periphery of the spool 221. Further, on both sides of the peripheral wall of the case 102 where the grooves 222 and 223 face the space, reserve-side ports 224a and 224b and pump-side ports 225a and 225b are provided symmetrically around the convex portion between the grooves, and further face the space of the grooves 222 and 223. Actuator side ports 226 and 227 are provided at the center of the peripheral wall of the case 102, respectively. And case 1
Pilot ports 228 and 229 for applying control pressure to the spool end are provided at both ends of 02. Then, the actuator side ports 226, 227 are connected to the oil flow path 99.

The left and right chambers 18 and 19 of the power steering 6 are connected to the pilot ports 228 and 229 of the in-phase control valve 98 via the oil passage 103, respectively. When a power stay pressure is generated, the neutral spool 221 is displaced. Then, switching between the reserve ports 224a, 224b and the pump ports 225a, 225b is performed. The pump ports 225a and 225b of the control valve 100 are connected to an oil pump 105 that is driven by a differential gear 104 and generates a hydraulic pressure according to the vehicle speed (high vehicle speed: increased hydraulic pressure). Thereby, the hydraulic pressure according to the vehicle speed and the moving amount of the spool 221 can be supplied to the left chamber 97a or the right chamber 97b in the steering direction of the rear power cylinder 90. That is,
The rear wheels 82a, 82b can be steered in the same direction as the front wheels 1a, 1b in accordance with the steering state of the front wheels 1a, 1b. The reserve ports 224a and 224b are connected to the reserve tank 106 receiving the return of the power steering 6.

Further, a spool valve type four-port throttle switching valve is used as the phase control valve 100 which is a main part of the present invention. The schematic structure of the throttle switching valve is shown in FIGS. 1 to 11.

Describing the switching valve, reference numeral 300 denotes an elongated valve body. A valve chamber 301 is formed in the valve main body 300 along the axial direction. An elongated spool 302 is provided in the valve chamber 301. The spool 302 has a valve chamber 301 at each end.
The slide is supported by a bearing portion 304 of an adapter 303 attached to the end of the valve body 300 so that the entire spool can slide along the axial direction of the valve body 300. In addition, a plug 306 (corresponding to a first pilot input port) having a hole 305 facing the spool end is attached to the end of each adapter 303, and constitutes the body of the control valve 100 together with the valve body 301. Each spring chamber 307 (also serving as a hydraulic chamber) formed between the plug 306 and the adapter 303 has a pair of springs 3 for urging the spool 302 toward the center.
08,308 are positioned to position the spool 302. Each of the plugs 306 is connected to an intermediate portion of the oil flow path 103 via a branch passage 312 so as to apply a power steering pressure serving as a first pilot pressure to the spool end. Reference numeral 309 denotes a washer provided at an end of the spool 302 for forming a spun ring seat, 310 denotes an air bleeder for adjusting the bearing 304 of the adapter 303, and 311 denotes a nut for preventing the adapter 303 and the plug 306 from loosening.

A through-hole 313 is slidably mounted on the outer periphery of the center of the spool 302. At both ends of the sleeve 313, a concave portion 315 accommodating a spring 314 is provided. The remaining ends of the pair of springs 314, 314 are connected to the spool 3
The sleeve 313 is urged from both sides by springs 314, 314, being locked by a ring-shaped portion 316 provided on the outer periphery of the end of 02.
That is, the entire sleeve is positioned on the spool 302. In addition, 317 is a washer interposed between the spring end and the ring-shaped portion 316, and 318 is a snap ring fixed to the inner peripheral portion on the opening side of the concave portion 315 for restricting the movement of the washer 317. A pair of pressure receiving chambers 319 and 320 facing the sleeve end is formed in a space surrounded by the adapter distal end surface around each ring-shaped portion 316 and the valve chamber portion. Note that the washer 317 and the snap ring 318 correspond to a sleeve end.

On the outer peripheral surface of the spool 302 covered with the sleeve 313, two chambers 321 and 322 each having an annular groove are provided in parallel. Also, on the inner peripheral surface of the sleeve 313, three chambers formed of an annular groove are located at three boundary portions of the chambers 321 and 322.
323 to 325 are provided. 326 is a guide recess formed at the boundary between the chambers 323 to 325. The chambers 321 and 322 are respectively provided with actuator ports 329 and 330 (fluid outlet ports) drilled on the upper surface of the valve body 300 through guide recessed portions of the sleeve 313 and passage spaces 327 and 328 formed on the peripheral surface of the valve chamber. ). The ports 329 and 330 are connected to the oil passages 101a and
Connected to 101b. The chamber 324 is connected to the valve body 300 via a passage space 331 formed in the sleeve portion and the peripheral surface of the valve chamber.
Is connected to an oil supply port 332 (corresponding to a fluid inlet port) provided on the upper surface of the oil tank. And this port 332
A port connected to a discharge portion of a constant flow rate (a constant flow rate regardless of the number of revolutions) oil pump 334 driven by the engine 20 together with the oil pump 13 via an oil supply path 333; The 332 can be supplied with a constant flow of oil.

Further, the remaining chambers 323 and 325 are respectively provided with passage spaces 335 and 336 formed in the sleeve portion and the peripheral surface of the valve chamber, and a communication passage 337 that communicates in parallel between the two passage spaces 335 and 336 formed in the valve body 300. It communicates with a reservoir port 338 drilled on the top of the 300. Then, this port 338 is connected to the reservoir tank 106 via a flow path 338a. Further, in the parallel communication passage 337, pressure receiving chambers 319 and 320 on both sides of the sleeve are connected in parallel via passages 339 and 339, respectively, to receive oil from the oil pump 334 into the pressure receiving chamber 31.
9,320. In addition, each passage 339,339
Each has a check valve 340 (a structure in which a ball 343 is pressed against a valve seat 344 by a valve rod 342 biased by a spring 341) for regulating the flow toward the reservoir tank 106 side.

Further, the pressure receiving chambers 319 and 320 communicate with each other via a communication passage 345 (corresponding to a flow passage) provided in the valve body 300. The variable orifice 346 is provided in the middle of the communication passage 345 (flow path).
(Or a variable choke, corresponding to a diaphragm device) is interposed. The detailed structure of the variable orifice 346 is the eighth.
This is shown in FIGS.

To explain the variable orifice 346, 347 is a communication passage
A through-passage formed along the direction perpendicular to the communication passage 345 in the middle of 345, a cylinder 348 (comprising a pipe) press-fitted in a part of the through-passage 347, and a 349 sliding into the cylinder 348 It is a piston freely arranged. Slots 350 and 351 are formed in the peripheral wall of the cylinder 348 and the shaft of the piston 349, respectively. A pin 352a is press-fitted between the ends of the long holes of the cylinder 348. This pin 352a is
9 is slidably inserted into the long hole 351 to position the piston 349 in the circumferential direction. Then, in conjunction with the movement of the piston 349 in the axial direction, the long hole 35 of the cylinder 348 is formed.
Communication (flow) formed by 0 and the long hole 351 of the piston 349
The area, that is, the aperture area can be varied. Needless to say, the throttle portion formed by the combination of the long holes 350 and 351 is arranged at a portion communicating with the communication path 345. The piston 349 is urged upward from a lower end of the through passage 347 by a spring 351a inserted together with the adapter 350a. I have to. The upper side of the through passage 347 communicates with a high-pressure side vehicle speed pilot pressure port 352 (corresponding to a second pilot input port) formed in the upper surface of the valve body 300. Further, a through hole 353 is formed in the peripheral wall portion on the low pressure side of the cylinder 348. And this through hole 3
Reference numeral 53 communicates with a low-pressure side vehicle speed pilot port 355 (corresponding to a second pilot input port) formed on the right side of the valve body 300 via a flow path 354 provided in the valve body 300.

The vehicle speed pilots 352 and 355 on the high and low pressure sides of the variable orifice 346 are connected to a vehicle speed sensitive pressure generator 356 built in the differential drive oil pump 105, and the vehicle speed generated from the vehicle speed sensitive pressure generator 356 increases as the vehicle speed increases. Therefore, the throttle amount of the variable orifice 346 can be changed in response to the vehicle speed by the hydraulic pressure (second pilot pressure) that increases the pressure. More specifically, the vehicle speed-sensitive pressure generator 356 has a fixed orifice (not shown) provided in the discharge portion of the oil pump 105 that rotates in proportion to the vehicle speed. Through the variable orifice 346.

As a result, the control valve 100 cuts the steering wheel 17 from the displacement of the spool 302 and the relative displacement of the sleeve 313 with respect to the spool 302 caused by the pilot pressure applied to the spool end and the pilot pressure applied to the variable orifice 346. A phase hydraulic pressure can be generated according to the time change rate of the power steering pressure (time differential value, which corresponds to the steering wheel angular velocity) and the vehicle speed. That is, the hydraulic pressure for the phase can be supplied to the cylinder chamber 92a or the cylinder chamber 92b of the rear power cylinder 90 as an output for steering the rear wheels 82a, 82b in the opposite direction to the front wheels 1a, 1b.

The oil flow paths 101a, 101b connected to the phase control valve 100 are connected to the plugs 54, 56 of the phase advance mechanism 14 via the branch paths 358, 358, and the momentary rear wheels 82a, 82b
At the same time as the phase, the front wheels 1a and 1b can be advanced to the side to be increased. However, in the drawing, a blind plug 360 is provided at the opening end of the passage.

FIG. 11 shows a schematic structure of such a control valve 100.

Next, the operation of the four-wheel steering device configured as described above will be described.

When the vehicle is traveling straight, the steering wheel 17 is in a neutral state, so that the front wheels 1a, 1b and the rear wheels 82a, 82b are oriented in the straight traveling direction.

When the steering wheel 17 is turned, for example, to the right turning side (medium-high speed) in order to turn from such a straight running state (turn-in), the cut-off angle is momentarily changed according to the steering angular speed and the vehicle speed. The rear wheels 82a and 82b are in opposite phases, and the front wheels 1a and 1b momentarily increase the steering angle from the input steering angle.

Specifically, when the steering wheel 17 is operated, this rotation is transmitted to the sun gear 25 of the first-stage planetary gear mechanism 21 via the column shaft 16, the intermediate joint 15, and the input shaft 24. Here, the ring gear 26 receives the steering force, but the ring gear 26 is
Since the rotation is fixed to 37, the rotation is further transmitted to the planetary gear 31 of the second-stage planetary gear mechanism 22 via the planetary gear 27. The ring gear 31 of the second-stage planetary gear mechanism 22 also tries to rotate by receiving the steering force. However, the ring gear 31 has a restoring force (ie, a force to return the ring gear 31 generated by the control valve 23 to the original position). The oil pressure generated by the oil pump 13 causes the sleeve 53
The force of the planetary gear 31 is transmitted from the sun gear 28 to the valve input shaft 7a and the torsion bar 8 as it is, because the relative displacement of the 69 always forces the relative displacement to zero. As a result, the rotation transmitted to the torsion bar 8 is transmitted to the pinion 5, and the front wheels 1a and 1b are steered in a direction in which the steering wheel 17 is turned. At the same time, the rotary valve 7 is operated by the rotation transmitted to the valve input shaft 7a, and the hydraulic pressure generated by the oil pump 13 is transmitted to the power cylinder 11
To the right room 19 to assist the operation of the steering wheel 17.

On the other hand, the spool of the in-phase control valve 98 is stroked in accordance with the power stay pressure of the power steering 6. Then, the oil discharged from the oil pump 105 is controlled by the stroke of the spool. That is, the control valve 98 generates a hydraulic pressure according to the vehicle speed (rear wheel rotation speed) and the power stay pressure. Then, this hydraulic pressure is applied to the rear power cylinder 90
Into the left ventricle 97a.

On the other hand, when the power stay pressure is applied as pilot pressure from the hole 305 of the plug 306 on the right side, the control valve 100 for the phase shifts the spool 30 by an amount proportional to this pressure.
2 is displaced to the left (x ₁ ).

Looking at the relationship between the displacement amounts, the product of the area of the end face of the spool 302 and the pilot pressure balances the elastic force of the right spring 314, so the following relational expression holds for the displacement amount.

_{a 1 · F 1 = K 1} · x 1 + f 1 i.e., is represented by _{x 1 = a 1 · F 1} -f 1 / K 1. Incidentally, a ₁ is the area of the spool end faces, K ₁ is the spring constant of the left spring 314, f ₁ preload value of the spring, F ₁ is the pilot pressure. However, spool 302
Ignore the friction of.

At this time, the displacement of the spool 302 causes the sleeve 313
Also try to move in the same direction. This requires that the oil in the pressure receiving chamber 319 move to the pressure receiving chamber 320 through the communication passage 345. However, since the variable orifice 346 is incorporated in the communication passage 345, the differential pressure ΔP
Occurs. Here, ΔP is represented as follows.

^{ΔP = δ · Qb 2/2} · Cd · d 2 where, [delta] is the fluid density, Qb is the flow rate through the throttle section, the cross-sectional area of d the diaphragm portion, Cd is a flow coefficient.

In the case of a choke structure, ΔP = 8 · π · μ · l · Qb / d ² . Here, 1 is the length of the throttle portion, and μ is the viscosity coefficient of the oil.

Then, the sleeve 313 is relatively shifted to the right side with respect to the spool 302 due to the differential pressure ΔP. The relative displacement y at this time is represented by y = ΔP · b ₂ −f ₂ / K ₂ . Incidentally, b ₂ is the area of the end face of the sleeve, K ₂ is the spring constant of the right spring 314, f ₂ is the pre-load value of the spring. However, the sliding resistance of the sleeve 313 is ignored.

Since a constant flow of oil generated by the oil pump 334 is supplied from the oil supply port 332, a differential pressure proportional to the relative displacement y is generated from the actuator ports 329 and 330. That is, the relative displacement y is, WaiarufaderutaPiarufakyubiarufaeruarufa1 / is a function of _{^{d 2, Qb = b 2 ·}} (x 1 -y) / t where, t is time holds (x ₁ -y ) ∝Pilot 306 pilot pressure.

This means that the control valve 100 has a differential value of one pilot pressure, as well as the other pilot pressure,
It can be seen that the hydraulic pressure can be controlled.

Therefore, as shown in the diagrams of FIGS. 13 and 14, the output hydraulic pressure is reduced from the actuator ports 329 and 330 according to the vehicle speed, and the hydraulic pressure controlled in proportion to the time change of the power steering pressure is output. (Actuator ports 329, 33 depending on the two pilot pressures)
Control the differential pressure of 0).

The hydraulic pressure (differential pressure) is applied to the rear power cylinder 90
Is supplied as an output to phase the rear wheels 82a and 82b, and is supplied to the plug 54 of the phase advance mechanism 14 as an output to increase the steering angle of the front wheels 1a and 1b.

That is, the rear wheels 82a and 82b attempt to steer the rear wheels 82a and 82b in the same direction as the rear wheels, and the output of the cylinder chamber 92b that attempts to steer the rear wheels 82a and 82b in the direction opposite to the front wheels. The steering is performed in accordance with the opposite-phase side angle obtained by the output synthesis with the output of the left chamber 97a.

Further, the front wheels 1a and 1b are controlled by the control pressure applied to the plug 54 on the left side of the phase advance mechanism 14 so that the front wheels 1a and 1b are turned further. That is, when the control pressure is applied to the plug 54, the phase advance mechanism 14 causes the spool 53 to slide rightward in proportion to the hydraulic pressure. Then, the sleeve 69 and the collar 68 follow the spool 53 by the restoring function performed by the oil pressure of the oil pump 13 and move to a position where the relative position with respect to the spool 53 becomes zero. As a result, the lever 60 rotates around the plate 64 as a fulcrum, and rotates the ring gear 29 clockwise. Here, since the planetary gears 27 and 31 are fixed by the steering wheel 17 held by the driver, the valve input shaft 7a and the torsion bar 8 are turned to the side of increasing the angle.

At the next moment, as the change speed of the steering wheel 17 stops, only the output from the in-phase control valve 98 according to the vehicle speed becomes the original steady-state four-wheel in-phase steering (normal in-phase four WS ) And stabilize the movement of the car.

Thus, four-wheel steering or four-wheel active steering with phase inversion can be realized using highly reliable hydraulic control. Of course, because of the pure mechanical valve structure, noise,
Reliability against radio interference is high.

[Effects of the Invention] As described above, according to the present invention, the pressure of the fluid input from the liquid inlet port is changed to a pressure corresponding to two inputs of the differential value of the first pilot pressure and the second pilot pressure. Can be controlled.

Therefore, the steering wheel angular velocity, which is the differential term of the steering angle,
Alternatively, it is possible to generate a pressure of a complicated factor required for hydraulic control, such as hydraulic pressure according to the two states of the time change rate of the power steering pressure and the vehicle speed, which is equivalent to that. It can be controlled by control.

[Brief description of the drawings]

1 to 19 show an embodiment of the present invention.
FIG. 1 is a front sectional view of a control valve for phase as a main part, FIG. 2 is a plan view of the control valve, FIG. 3 is a sectional view of the control valve along BB in FIG. 1, and FIG. FIG. 5 is a side view of the control valve, FIG. 5 is a partial bottom view of the control valve, FIG. 6 is a cross-sectional view of the control valve along line CC in FIG. 5, and FIG. 7 is FIG. FIG. 8 is a cross-sectional view showing the structure around the drawing device along line AA, FIG. 8 is a cross-sectional view showing the drawing device, FIG. 9 is a cross-sectional view of the drawing device along line DD in FIG. The figure is an enlarged front view of the throttle section of the throttle device, FIG. 11 is a schematic configuration diagram of a phase control valve, FIG. 12 is a view showing the operation of the control valve, and FIG. 13 is a phase control valve. Diagram showing output characteristics of valve against pilot pressure, Fig. 14 And FIG. 15 is a diagram showing a four-wheel steering system to which the present invention is applied, and FIG.
FIG. 17 is a sectional view showing a control valve for the in-phase mechanism, FIG. 17 is a perspective view showing a partly sectional view of the phase advance mechanism, FIG. 18 is a sectional view showing the periphery of the planetary gear mechanism of the phase advance mechanism, and FIG. It is sectional drawing which shows the structure around the control valve of a phase mechanism. 100 ... control valve, 300 ... valve body, 302 ...
Spool, 306: plug (first pilot input port), 313: sleeve, 319, 320: pressure receiving chamber, 321-325
... chamber (opening / closing passage), 329, 330 ... actuator port (fluid outlet port), 332 ... oil supply port (fluid inlet port), 345 ... communication passage (flow path), 346 ...
Variable orifice (throttle device), 352, 355 ... Vehicle speed pilot port (second pilot input port).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadao Tanaka 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Keiji Fujii 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Masayoshi Nishimori 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Hiroyuki Masuda 1 Nakashinagiri, Hashime-cho, Okazaki City, Aichi Prefecture Address: Mitsubishi Motors Engineering Co., Ltd. Okazaki Office (56) References JP-A-62-110573 (JP, A)

Claims (1)

(57) [Claims] 1. A valve body, a spool slidably provided in the valve body, a sleeve slidably provided on an outer periphery of the spool, and a sleeve provided on an end face side of the sleeve with the end of the sleeve facing the sleeve. A pair of pressure receiving chambers filled with fluid, and a first end provided on the spool end provided in the valve body.
A first pilot input port for inputting a pilot pressure, and a flow path connected between the pressure receiving chambers for relatively displacing the spool and the sleeve in accordance with the pressure of the pilot pressure input from the first pilot input port. A second pilot input port provided in the valve body for inputting a second pilot pressure, and a second pilot pressure interposed in the flow path and input from the second pilot input port; A throttle device that can vary the amount of relative displacement between the spool and the sleeve according to pressure; a fluid inlet port provided on the valve body; and a relative displacement between the spool and the sleeve provided on the spool and the sleeve. An opening / closing passage for varying the pressure of the fluid input from the fluid inlet port in accordance with the amount, and a fluid provided in the valve body and varying the pressure. Control valve, characterized by comprising a fluid outlet port for outputting.