WO1995023086A1

WO1995023086A1 - Pressure control device

Info

Publication number: WO1995023086A1
Application number: PCT/JP1995/000291
Authority: WO
Inventors: Toshinori Aihara; Tatuyoshi Maruyama; Koichi Komatsu
Original assignee: Unisia Jecs Corporation
Priority date: 1994-02-25
Filing date: 1995-02-27
Publication date: 1995-08-31
Also published as: KR960701767A; DE19580329T1

Abstract

A pressure control device comprising a spool (38) slidably fitted over a valve body (31) so as to partition off a first liquid chamber (40), second and third liquid chambers (44, 45) formed between the spool (38) and the valve body (31), the second liquid chamber being connected to an oil pump (61) and the third liquid chamber being connected to an actuator, valve means (42, 43) for shutting off communication between the second and third liquid chambers (44, 45), valve operating means (54) for moving the spool (38) toward the first liquid chamber (40) side against biassing means (46, 47) for biassing the valve means (42, 43) into a valve closing state so as to establish communication between the second and third liquid chambers (44, 45), an operation liquid passageway (67) for establishing communication between the first liquid chamber (40) and third liquid chamber (45), and a directional control valve (69) disposed along the length of the operating liquid passageway (67) so as to shut off communication between the first liquid chamber (40) and third liquid chamber (45) when the pressure inside the third liquid chamber (45) exceeds a certain level.

Description

Description Invention <Name Pressure control device Technical field

The present invention relates to a pressure control device having a non-linear characteristic of a hydraulic fluid generated with respect to an operation force, and is particularly suitable for application to a power steering device. Background art

In a power steering device using hydraulic pressure, a pressure control device for supplying a hydraulic pressure corresponding to a steering force to a power cylinder is incorporated, and the hydraulic pressure supplied to the power cylinder by the pressure control device is used as an auxiliary steering force. We are using.

As an example of such a pressure control device, for example, a pressure control valve disclosed in Japanese Patent Application Laid-Open No. 62-320286 is known. In this pressure control valve, an increase or decrease in oil pressure with respect to the actuator for steering corresponds only to the opening / closing operation of a valve spool constituting the pressure control valve. In other words, when the pressing force of the plunger generated according to the steering torque increases, the valve spool opens and high-pressure hydraulic oil from the oil pump is guided to the actuator, and at the same time, the feedback provided on the back of the valve spool is provided. This high-pressure oil acts on the chamber and generates a steering reaction force that pushes back the valve spool.

The conventional pressure control valve disclosed in Japanese Patent Application Laid-Open No. 62-332026 discloses that when the pressing force of the plunger generated according to the steering torque increases, the valve spool opens and the pressure from the oil pump increases. Since high-pressure hydraulic oil is guided to the actuator and the feedback chamber, an auxiliary steering force is generated by hydraulic pressure proportional to the steering torque. At high load such as turning, the steering torque was relatively large. Therefore, in order to reduce the steering torque at the time of high load such as stationary, If the hydraulic reaction force from the feedback chamber was set to be small, the required steering force during normal running would be too small, which could impair the maneuverability.

Accordingly, an object of the present invention is to provide a pressure control device capable of changing the ascending characteristic of the hydraulic fluid with respect to the spool operation force in the middle.

Another object of the present invention is to provide a power steering apparatus which has a non-linear characteristic in hydraulic pressure supplied to a power cylinder with respect to a steering force, and in particular, can reduce a steering torque at the time of stationary steering as compared with a conventional one. Aim.

Another object of the present invention is to provide a power steering device which does not require the use of a seal member and can improve durability. Disclosure of the invention

A pressure control device according to the present invention comprises: a spool slidably fitted in a valve receiving hole formed in a valve body; and a first liquid chamber partitioned by the spool at one end of the valve receiving hole. A second liquid chamber formed between the valve body and the spool and connected to a hydraulic fluid supply source and a third liquid chamber connected to an actuator, and the spool is connected to the first liquid chamber. Valve operating means that can move to the liquid chamber side and operate so that the second liquid chamber communicates with the third liquid chamber; and communicates the first liquid chamber with the third liquid chamber. And a communication state between the first liquid chamber and the third liquid chamber when the third liquid chamber has a predetermined pressure or more and is interposed in the middle of the hydraulic liquid path. And a switching valve for shutting off.

In addition, a pressure control device according to the present invention includes a spool that is slidably fitted in a valve receiving hole formed in a valve body, and a first partition partitioned to one end of the valve receiving hole by the spool. A second liquid chamber respectively formed between the valve body and the spool and connected to the hydraulic fluid supply source, and a third liquid chamber connected to the actuator and the spool. Valve operating means which can be moved to the first liquid chamber side and operated so that the second liquid chamber and the third liquid chamber communicate with each other; the first liquid chamber and the third liquid A hydraulic fluid passage communicating with the third fluid chamber, the hydraulic fluid passage being interposed in the middle of the hydraulic fluid passage, and (1) A switching valve that cuts off a communication state between the first liquid chamber and the third liquid chamber and connects the first liquid chamber to a drain passage branched from the hydraulic fluid passage. It is assumed that.

In addition, a pressure control device according to the present invention includes a spool slidably fitted in a valve receiving hole formed in a valve body, and a first partition partitioned on one end side of the valve receiving hole by the spool. A second liquid chamber respectively formed between the valve body and the spool, and connected to a hydraulic fluid supply source; and a second liquid chamber that can communicate with the second liquid chamber and a drain passage. A third chamber connected to the reservoir via a chamber and a third chamber connected to the actuator, the chamber and the third chamber shut off, and the spool is connected to the first chamber. Valve operating means which can be moved to the side to operate the second liquid chamber and the third liquid chamber to communicate with each other; and an operation for communicating the first liquid chamber with the third liquid chamber. A fluid passage, and a third fluid chamber interposed in the middle of the working fluid passage when the pressure of the third fluid chamber becomes a predetermined pressure or more. A switching valve for shutting off a communication state between the first liquid chamber and the third liquid chamber is provided.

In addition, a pressure control device according to the present invention includes a spool slidably fitted in a valve receiving hole formed in a valve body, and a first partition partitioned on one end side of the valve receiving hole by the spool. A second liquid chamber respectively formed between the valve body and the spool, and connected to a hydraulic fluid supply source; and a second liquid chamber that can communicate with the second liquid chamber and a drain passage. A third chamber connected to the reservoir via a chamber and a third chamber connected to the actuator, and the chamber chamber and the third chamber closed. Valve operating means that can move the second liquid chamber and the third liquid chamber to communicate with each other, and a hydraulic fluid that communicates the first liquid chamber with the third liquid chamber. The third fluid chamber is interposed in the middle of the hydraulic fluid passage and the third fluid chamber has a predetermined pressure or more. A switching valve for cutting off a communication state between the first liquid chamber and the third liquid chamber and connecting the first liquid chamber to a drain passage branched from the hydraulic fluid passage. It is assumed that.

Further, a pressure control device according to the present invention includes a spool that is slidably fitted into a valve receiving hole formed in a valve body, and a spool between the spool and the valve body. JP95 / 00291 First liquid chamber formed respectively and connected to the actuator and second liquid chamber connected to the hydraulic liquid supply source, and the first and second liquid chambers are communicated with each other. A spool operating means capable of operating a spool, an auxiliary urging means connected to the first liquid chamber via an auxiliary liquid path, and capable of urging the spool operating means; provided in the middle of the auxiliary wave path The auxiliary urging means is provided with an on-off valve for guiding the hydraulic fluid from the first liquid chamber when the pressure of the first liquid chamber becomes equal to or higher than a predetermined pressure.

In addition, a pressure control device according to the present invention includes a spool that is slidably fitted in a valve receiving hole formed in a valve body, and a spool formed between the spool and the valve body, respectively. And a second chamber connected to the hydraulic chamber and a chamber chamber which can communicate with the first chamber and which communicates with the oil reservoir via an oil drain. A liquid chamber, a first liquid chamber and a chamber chamber, and a spool operating means capable of operating the spool so that the first and second liquid chambers communicate with each other; and an auxiliary wave path. An auxiliary urging means connected to the first liquid chamber and capable of urging the spool operating means; provided in the middle of the auxiliary liquid path, when the first liquid chamber has a predetermined pressure or higher. An on-off valve for guiding the hydraulic fluid from the first fluid chamber to the auxiliary urging means. The one in which the features.

Further, the power steering device according to the present invention includes a pair of hydraulic control valves for supplying and discharging hydraulic oil to and from a pair of cylinder chambers formed in the power cylinder, respectively, and a valve drive for operating the pair of hydraulic control valves. A hydraulic steering valve having a mechanism, wherein the hydraulic control valve is slidably fitted in a valve receiving hole formed in a valve body, and the spool accommodates the valve by the spool. A first oil chamber partitioned at one end of the hole, a second oil chamber formed between the valve body and the spool and supplied with pressure oil from an oil pump, and one of the power cylinder A third oil chamber that communicates with the cylinder chamber; and a chamber chamber that can communicate with the third oil chamber and communicates with the oil reservoir via a drainage passage. The said third Isolation from the chamber and the Chiyanba chamber, which further communicates with said spool to move to the first oil chamber side second oil chamber and the third oil chamber, the first The oil chamber is provided with hydraulic pressure adjusting means for adjusting the oil pressure in the first oil chamber in accordance with the operation state of the vehicle. Here, the hydraulic pressure adjusting means includes an oil pump for supplying pressure oil to the first oil chamber, and an oil discharge passage communicating with the first oil chamber and incorporating a throttle. A branch passage communicating between the first oil chamber and the third oil chamber, valve means for restricting or opening or closing the branch passage, and a discharge passage communicating with the first oil chamber and having a restriction incorporated therein. It is desirable to have an oil passage. It is particularly effective that the driving state of the vehicle is the traveling speed of the vehicle.

Further, the power steering device according to the present invention is configured such that an input shaft to which a steering force is input and an output shaft for driving a steering member are connected by a torsion bar, and actuated according to a relative rotation amount between the input shaft and the output shaft. A power steering device having a spool valve type valve operating mechanism, wherein the spool valve type valve operating mechanism is disposed on a fixed member that rotatably supports the input shaft and the output shaft, and the input shaft and the output shaft A motion direction converting means for converting the relative rotation of the two shafts into an axial motion of the two shafts is provided, and the valve operating mechanism is operated by the motion direction converting means.

Further, in the power steering apparatus according to the present invention, the spool valve-type valve operating mechanism is disposed in parallel with the input shaft, and the movement direction changing means is slidably fitted on the input shaft, A sleeve member formed with an inclined guide portion inclined with respect to the axis and a guide portion in the axial direction; and a lever for driving the valve operating mechanism, integrally connected to the sleeve member in the axial direction, and A ring member rotatable in the direction, a drive pin protruding from the input shaft and engaging with the inclined guide portion, and a guide bin fixed to the output shaft and engaging with the axial guide portion. It is characterized by having.

Further, in the power steering apparatus according to the present invention, the spool valve-type valve operating mechanism is disposed in parallel with the input shaft, and the movement direction changing unit is slidable integrally with the input shaft in an axial direction. A sleeve member fitted with a sleeve member and a ring member, the sleeve member having an inclined guide portion inclined with respect to an axis and an axial guide portion, and a lever for driving the valve operating mechanism; A ring member rotatable with respect to one member, and the inclination protruding from the input shaft. It is characterized by comprising a drive pin engaged with the guide portion, and a guide bin fixed to the output shaft and engaged with the axial guide portion.

Further, in the power steering apparatus according to the present invention, the spool valve type operating mechanism is disposed in a direction perpendicular to the input shaft, and the movement direction changing means is integrally slidably fitted in the input shaft in the axial direction. A first sleeve member provided with a first inclined guide portion inclined with respect to the axis and an axial guide portion, and a first sleeve member inclined with respect to the axis. A second sleeve member on which a ring member having a valve operating mechanism driving lever and a pin engaged with the second inclined guide portion is fitted, and a second sleeve member is fitted to the input shaft; A drive pin engaged with the first inclined guide portion; and a guide bin fixed to the output shaft and engaged with the axial guide portion.

The power steering apparatus according to the present invention is characterized in that the fixed member is a housing fixed to a cylinder that slidably supports a steering member.

According to the pressure control device of the present invention, when the fluid pressure in the third fluid chamber connected to the actuator becomes higher than a predetermined value, the first fluid with respect to the movement of the spool to the first fluid chamber side Since the reaction force of the hydraulic pressure in the room is eliminated, the operating force of the spool by the valve operating means is reduced when it is equal to or more than a predetermined value. The steering can be more easily performed in a heavy load such as stationary operation than before.

Further, according to the pressure control device of the present invention, when the first liquid chamber connected to the actuator becomes a predetermined pressure or more, the hydraulic fluid from the first liquid chamber is supplied to the auxiliary urging means, Since the operating force of the spool is supplemented by the auxiliary biasing means, the operating force of the spool by the spool operating means can be reduced by a predetermined amount or more. Without changing the characteristics, it is possible to steer more easily than before with high loads such as stationary.

Further, according to the power steering device of the present invention, the hydraulic pressure adjusting means for adjusting the hydraulic pressure in the first oil chamber according to the driving state of the vehicle is provided, and the spool is moved. The hydraulic pressure in the first oil chamber, which generates a hydraulic reaction force to the movement, is adjusted according to, for example, the vehicle speed, so that the steering torque during only high loads such as stationary operation is reduced compared to the conventional one. Can be.

Further, according to the power steering device of the present invention, since the spool valve-type valve operating mechanism is disposed on the fixed member, it is possible to eliminate the need for a seal member that causes a problem of durability. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic sectional view of a pressure control device according to an embodiment of the present invention applied to a power steering device.

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

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

FIG. 4 is an enlarged sectional view of a main part of the pressure control device of FIG.

FIG. 5 is a graph showing the relationship between the steering torque in the pressure control device of FIG. 1 and the pressure of the hydraulic oil in the connecting oil passage.

FIG. 6 is a view similar to FIG. 4, showing another embodiment of the present invention.

FIG. 7 is a schematic sectional view of a pressure control device according to another embodiment of the present invention applied to a power steering device.

FIG. 8 is an enlarged sectional view of a main part of the hydraulic control device of FIG.

FIG. 9 is a graph showing the relationship between the steering torque and the hydraulic pressure supplied to the power cylinder in the hydraulic control device of FIG.

FIG. 10 is a view similar to FIG. 7 showing a hydraulic control device according to another embodiment of the present invention.

FIG. 11 is an enlarged sectional view of a main part of the hydraulic control device of FIG.

FIG. 12 is a graph showing the relationship between the steering torque and the hydraulic pressure supplied to the power cylinder in the hydraulic control device of FIG.

FIG. 13 is a view similar to FIG. 11 showing a main part of a hydraulic control device according to another embodiment of the present invention.

Fig. 14 is a map diagram showing the relationship between the vehicle speed and the oil pressure in the drainage passage and the on / off state of energization to the solenoid in the hydraulic control device of Fig. 13, FIG. 15 is a graph showing the relationship between the steering torque and the hydraulic oil and pressure in the power cylinder in the hydraulic control device shown in FIG.

FIG. 16 is a schematic cross-sectional view of a pressure control device according to still another embodiment of the present invention applied to a power steering device.

FIG. 17 is a sectional view taken along the line 17-17 in FIG.

FIG. 18 is an enlarged sectional view of a main part of the pressure control device of FIG.

FIG. 19 is the same stick as FIG. 17 showing still another embodiment of the present invention.

FIG. 20 is a schematic sectional view showing a hydraulic control device according to another embodiment of the present invention applied to a power steering device.

FIG. 21 is a view similar to FIG. 20 showing a hydraulic control apparatus according to still another embodiment of the present invention.

FIG. 22 is a view similar to FIG. 20 showing a hydraulic control apparatus according to still another embodiment of the present invention.

FIG. 23 is a sectional view taken along the line 23-3-23 in FIG.

FIG. 24 is a sectional view taken along the line 24-24 in FIG. BEST MODE FOR CARRYING OUT THE INVENTION

A pressure control device according to an embodiment of the present invention applied to a power steering device will be described in detail with reference to FIGS.

As shown in FIG. 1 showing a schematic structure of the present embodiment, a cylinder 11 extending in the width direction (left and right direction in the figure) of a vehicle body (not shown) is provided with a rack rod having tie openings (not shown) connected to both ends. 1 is penetrated so as to be slidable in the left-right direction in the figure, and one end of the rack rod 12 held by the cylinder 11 is connected to one end of the cylinder 11 by two oil chambers 1 on the left and right. Biston 14 partitioning into 3 L and 13 R is integrally fitted. In the center of the cylinder 11, the upper and lower ends of a pinion shaft 15 intersecting with the rack bar 12 are rotatably held via bearings 16 and 17, respectively. The rack 19 formed on the rack bar 12 is aligned with the pinion 18 formed on the rack. That is, by driving and rotating the pinion shaft 15, the tie rod changes the direction of the steered wheels (not shown) via the rack bar 12. As described above, in the present embodiment, the piston of the present invention is slidably fitted to the cylinder 11 to partition the cylinder 11 into two oil chambers 13 L and 13 R. Although the rack bar 12 equipped with 14 is employed, it is also possible to employ an actuator of other structure.

A lower end of a torsion bar spring 20 is selectively fitted to the center upper portion of the pinion shaft 15, and a cylindrical input shaft 21 coaxially surrounding the torsion bar spring 20 is a pair of upper and lower bearings. The pinion shaft 15 and the housing 24 are held rotatably relative to the upper end of the pinion shaft 15 and the housing 24 via 22 and 23, respectively. A connecting pin 25 for integrally connecting the torsion bar spring 20 and the input shaft 21 is mounted on an upper end of the input shaft 21. A steering handle (not shown) is provided on the upper end of the input shaft 21. The lower end of the steering shaft 26 having the upper end attached thereto is serration-fitted. That is, the rotational force of the steering shaft 26 due to the operation of the steering wheel with respect to the pinion shaft 15 is transmitted only through the torsion bar spring 20.

As shown in FIG. 1 and FIG. 2 showing the cross-sectional structure taken along the line 2-2, the housing 24 in which the inside is held in a liquid-tight state has a lower end portion on a pinion shaft 15 and a plurality of connecting pins 2. A cylindrical valve rotor 28 connected to the housing 24 is slidably housed in the housing 24. A fan-shaped lever holding space 29 is formed above the valve rotor 28 surrounding the input shaft 21. The lever holding space 29 is integrated with the center of the input shaft 21. A V-shaped spool operation lever 30 which is fitted in the housing is housed so as to be relatively rotatable.

As shown in FIGS. 1 to 4, the valve opening 28 in this embodiment is formed by a valve holder 31 and a pair of cover plates 32, 33, and is assembled so as to form a cylindrical shape as a whole. . The valve holder 31 has a pair of stepped holes 34 extending in a direction perpendicular to the direction in which the input shaft 21 penetrates. A seal cap 35 is tightly attached to the end, and a cover sleeve 37 into which a seal plug 36 is press-fitted is attached to each of the large-diameter open ends.

The configuration of the pair of stepped holes 34 is exactly the same, —One end of a cylindrical spool 38 L, 38 R (sometimes simply described as 38) is slidably fitted to the valve 37 via a 0 ring 39. As a result, the first oil chambers 40 L and 40 R surrounded by the inner periphery of the seal plug 36 and the cover sleeve 37 and one end surface of the spool 38 (may be simply referred to as 40). There is). At the center of the spool 38, the other end of which is slidably fitted to the small diameter portion of the stepped hole 34 via the O-ring 41, there is a stepped hole 34 that functions as a valve seat. A conical valve body 43 that can abut the step portion 42 is integrally formed. The inner peripheral side of the small diameter portion of the stepped hole 34 located between the other end of the spool 38 and the valve element 43 is the second oil chamber 44 L, 44 R (simply, 4 4 And the inner peripheral side of the large diameter portion of the stepped hole 34 located between the valve body 43 and the cover sleeve 37 is the third oil chamber 45 L, 4 5 R (may be simply written as 4 5).

In this embodiment, the second oil chamber 44 and the third oil chamber 45 are partitioned by the step portion 42 and the valve element 43, but these two oil chambers 44, 45 The spool

If a structure capable of blocking the 3 8, so as to employ other well-known structures is not limited to this embodiment may _c Also, in this embodiment the valve holder 3 1 in terms of ease of manufacture is Although the cover sleeve 37 and the cover sleeve 37 are formed separately and function as the valve body of the present invention, it is also possible to adopt another divided structure.

In the first and second oil chambers 40, 44, a valve body 43 is in contact with the stepped portion 42 of the stepped hole 34, and the second oil chamber 44 and the third oil chamber Compression coil springs 46, 47 for urging the spool 38, respectively, so as to block the communication with the spool 45 are housed.

At the center of the spool 38, one end is connected to a third oil chamber through a communication hole 48.

An oil discharge guide passage 49 is formed which communicates with the seal cap 45 and opens at the other end toward the seal cap 35. Further, an inner flange 50 is formed on the seal cap 35 side of the small diameter portion of the stepped hole 34, and a stepped hole 3 located between the inner flange 50 and the seal cap 35 is formed. The small-diameter portion of 4 (hereinafter, referred to as the chamber) 5 1 is connected to the oil drain passage 52 It is connected to the sump 5 3.

In the small-diameter portion of the stepped hole 34 between the inner flange 50 and the other end of the spool 38, disc-shaped plungers 54 L and 54 R (when simply described as 54) The plunger 54 is slidably accommodated, and the plunger 54 has a conical poppet 5 on its spool 38 side that can abut the open end of the oil discharge guide passage 49 to close it. 5 are protruding. Around the poppet 55, a plurality of communication holes 56 are formed for communicating the chamber chamber 51 described above and the oil discharge guide passage 49 side. On the other side of the plunger 54, there are provided drive pins 58L, 58R (simply, 58 and 85R) which are slidably engaged with an elongated hole 57 formed at the end of the spool operation lever 30 '. Are sometimes linked together.

That is, when a relative rotation difference is generated between the torsion bar spring 20 and the input shaft 21 by the operation of the steering handle, that is, when a relative rotation difference is generated between the valve port 28 and the spool operation lever 30, the drive pin is driven. Plunger 54 slides in stepped hole 34 through 58, and one of plungers 54 piles on the spring force of compression coil springs 46, 47 to press spool 38 and to push Pet 5 5 Force Close the oil drain guide passage 49. Conversely, the other side of the plunger 54 moves to the inner flange 50 side, and the communication state between the chamber chamber 51 and the oil discharge guide passage 49 via the communication hole 56 is ensured. . Therefore, between the spool 38 and the plunger 54, the spool 38 and the plunger 54 are urged so as to be separated from each other, and the opening ends of the port 55 and the oil discharge guide passage 49 are urged. A compression coil spring 59 is interposed between the torsion bar spring 20 and the input shaft 21 so that there is no relative rotation difference between the torsion bar spring 20 and the input shaft 21. When there is no relative rotation difference between the operation lever 30 and the chamber chamber 51, the oil discharge guide passage .49 is in communication with the oil discharge guide passage 49 through the communication hole 56. The drive pin 58, the plunger 54, and the port 55 via the spool 26 and the spool operation lever 30 constitute a valve operating means of the present invention.

An oil pump 61 for pumping hydraulic oil from an oil reservoir 53 to the second oil chamber 44 is provided in a pressure oil supply path 60 facing the second oil chamber 44. oil A pressure oil supply path 60 between the pump 61 and the second oil chamber 44 includes an accumulator 62 for accumulating pressure in order from the second oil chamber 44 side, and a pressure oil supply path 60 inside the pressure oil supply path 60. A pressure switch 63 that detects the pressure of the hydraulic oil of the oil pump and a check valve 64 that prevents the hydraulic fluid from flowing back from the second oil chamber 44 to the oil pump 61 are incorporated. . The electric motor 65 that drives the oil pump 61 switches between an operating state and a stopped state based on a detection signal from the pressure switch 63 so that the pressure oil supply passage 60 falls within a predetermined pressure range. It has become.

Further, connection oil passages 66 L, 66 R (simply, 66 R) connecting the third oil chambers 45 L, 45 R and the oil chambers 13 L, 13 R formed in the cylinder, respectively. In some cases, there is a branch oil passage 67 L, 67 R (sometimes simply described as 67) communicating with the first oil chamber 40 L, 4 OR. It is formed as the hydraulic fluid passage of the present invention, and in the middle of the branch oil passages 67 L, 67 R, when the hydraulic oil in the connection oil passages 66 L, 66 R becomes higher than the set pressure. And the first oil chambers 40 L, 40 R and the oil drain passages 68 L, 68 R (sometimes simply described as 68) connected to the oil sump 53 are connected and connected. A 3-port 2-position switching valve 69 L, 69 R (sometimes simply described as 69) that shuts off the oil passages 66 L, 66 R and the branch oil passages 67 L, 67 R It has been incorporated. That is, the pressure of the hydraulic oil in the pilot oil passages 71 L and 71 R of the 3-port 2-position switching valve 69 is lower than the spring force of the spring 70 of the 3-port 2-position switching valve 69. In this state, the branch oil passage 67 and the drain oil passage 68 are shut off and the connection oil passage 66 and the branch oil passage 67 are in communication with each other, but they are connected to the connection oil passage 66. When the pressure of the hydraulic oil in the pilot oil passage 7 1 becomes larger than the spring force of the spring 70 of the 3-port 2-position switching valve 69, the connection oil passage 66 and the branch oil passage 67 are cut off. However, instead of the branch oil passage 67 and the oil drain passage 68 communicate with each other ^ z. o

The sliding contact between the cylinder 11 and the housing 24 and the valve rotor 28 is made up of a drain oil passage 52, a pressure oil supply passage 60, a connection oil passage 66, and a branch oil As shown in FIG. 1, a plurality of annular grooves for communicating the passages 67 are respectively formed in a sealed state, but as for the structure of this part, for example, U.S. Pat. No. 4,953,416 No.Japan Patent Showa 60-1 9 9 7 6 5 Since it is well-known in Japanese Patent Application Publication Nos. H07-26103, further description will be omitted.

Therefore, when the steering wheel is operated clockwise in FIG. 2, for example, the steering force is transmitted to the pinion shaft 15 and the valve opening 28 through the torsion rod spring 20 via the steering shaft 26. On the other hand, the spool operation lever 30 integral with the input shaft 21 is also transmitted. Here, if the rack bar 12 is hard to move rightward in FIG. 1 due to frictional resistance between the road surface and the wheels (not shown), the torsion will occur with respect to the rotation angle of the input shaft 21. The rotation angle of the bar spring 20 becomes smaller. As a result, the spool operation lever 30 rotates clockwise relative to the valve port 28 in FIG. 2 in the lever holding space 29 of the valve rotor 28, and through the drive pin 58L. The plunger 54L moves forward to the spool 38L side, and the port 55 blocks the oil discharge guide passage 49, and is further piled on the spring force of the compression coil springs 46, 47 to make the spool 38 Push L to the first oil chamber 40 L side. As a result, the second and third oil chambers 44 L and 45 L are in communication with each other, and the hydraulic oil from the pressure oil supply passage 60 is connected to the oil chamber 13 L via the connection oil passage 66 L. While supplied, the plunger 54R moves away from the spool 38R via the drive pin 58R, but the oil discharge guide passage 49 communicates with the chamber 51 via the communication hole 56. In this state, the piston 14 is urged to the right side in FIG. 1 together with the rack rod 12 by the pressure of the hydraulic oil in the oil chamber 13 L. As a result, the pinion shaft 15 also rotates clockwise in FIG. 2 together with the valve port 28, and the relative rotation of the torsion bar spring 20 with respect to the input shaft 21 is cancelled.

When the steering wheel is operated clockwise in Fig. 2, when the rotation angle of the torsion bar spring 20 is smaller than the rotation angle of the input shaft 21, the opposite is true for the second and third oil wheels. The chambers 44R and 45R are in communication with each other, and the pressure of hydraulic oil in the oil chamber 13R urges the piston 14 along with the rack rod 12 to the left in Fig. 1, and the pinion shaft 15 is also a valve. With counterclockwise rotation 28, it rotates counterclockwise in FIG. 2 and the relative rotation of the torsion bar spring 20 with respect to the input shaft 21 is cancelled.

In other words, when a relative rotation difference occurs between the torsion bar spring 20 and the input shaft 21, hydraulic oil is supplied to one of the oil chambers 13 L and 13 R so as to eliminate the difference, Since the rack bar 12 is forcibly pushed out in the steering direction by the oil pressure, the steering operation can be performed with a small steering force. In this case, As shown in FIG. 5, which shows the relationship between the steering torque applied to the rudder shaft 26 and the pressure of the hydraulic oil in the third oil chamber 45, the oil discharge guide passage 49 is closed with the movement of the plunger 54. When the spool 38 is pushed into the first oil chamber 40, the first oil chamber 40 is compressed and the second and third oil chambers 44, 45 are in communication. The hydraulic oil from the oil pump 61 starts to be supplied to the connection oil passage 66 side, and the oil pressure in the connection oil passage 66 increases. Then, a steering reaction force acts on the input shaft 21 side from the drive pin 58 through the spool operation lever 30 in proportion to the increase in the oil pressure, and unless the steering torque increases, the spool 3 8 Is pushed back to the right in FIG. 4, and the second oil chamber 44 and the third oil chamber 45 are shut off. However, when the steering torque is increased by overcoming the steering reaction force from the first oil chamber 40, the hydraulic pressure in the connection oil passage 66 becomes equal to or higher than a predetermined pressure, and the 3-port 2-position switching valve 6 9 is switched so that the branch oil passage 67 communicates with the oil discharge passage 68, and the pressure in the second oil chamber 40 is reduced. As a result, the steering reaction force from the first oil chamber 40 is obtained. Therefore, the hydraulic oil from the pressure oil supply passage 60 is supplied to the connection oil passage 66 side without increasing the steering torque at that rate, and the hydraulic pressure rises.

For this reason, as shown by the two-dot chain line in FIG. 5, the steering oil and the hydraulic oil pressure in the connection oil passage 66 exceed the predetermined steering torque more than the conventional steering torque that is in a proportional relationship throughout. The pressure of the vehicle can be increased more rapidly, and steering in a stopped state, that is, so-called stationary steering can be easily performed.

As shown in FIG. 2, when the relative rotation difference between the torsion bar spring 20 and the input shaft 21 disappears, that is, when the steering torque becomes 0, the plunger 54 returns to the neutral state shown in FIG. Hydraulic oil in the oil chamber 4 5 passes from the communication hole 48 to the oil discharge guide passage 49 and the communication chamber 56, passes through the chamber chamber 51, and is discharged to the oil reservoir 53 via the oil discharge passage 52. At the same time, the three-port two-position switching valve 69 is switched by the spring force of the spring 70, and the connection oil passage 66 and the branch oil passage 67 are communicated.

In the above-described embodiment, the first oil chamber 40 is connected to the oil discharge passage 68 when the hydraulic oil in the connection oil passage 66 exceeds a predetermined pressure by using the 3-port 2-position switching valve 69. To reduce the steering reaction force abruptly. As shown in FIG. 6 showing the schematic structure of the pressure control device in the embodiment, the connection oil passage 66 and the branch oil passage 67 are shut off using a two-port two-position switching valve 72, The hydraulic oil in the oil chamber 40 may be drained little by little as the steering torque increases. In other words, the drain oil passage 75 connected to the oil reservoir 53 is connected to the middle of the branch oil passage 67, and a relief valve 76 is incorporated in the middle of the drain oil passage 75, and the spring of the relief valve 76 is mounted. The spring force of 7 is set to be greater than the spring force of the blooming 2-port 2-position switching valve 7 2 spring 7 4 and the oil in the pilot oil passage 7 8 through which the hydraulic oil in the oil drain passage 75 is guided When the oil pressure becomes larger than the spring force of the spring 77, a part of the hydraulic oil in the first oil chamber 40 is discharged from the oil discharge passage 75 through the relief valve 76 to the oil reservoir 53. I am trying to.

Therefore, the pressure of the hydraulic oil in the pilot oil passage 73 of the 2-port 2-position switching valve 72 communicating with the connection oil passage 66 is larger than the spring force of the spring 74 of the 2-port 2-position switching valve 72. When it becomes larger, the connection oil passage 66 and the branch oil passage 67 are shut off, and the pressure of the hydraulic oil in the first oil chambers 40 L and 40 R is maintained, so that the The steering reaction force does not decrease sharply, and the relationship between the steering torque and the pressure of the hydraulic oil in the connection oil passage 66 can be changed more smoothly than in the previous embodiment. The opening operation of the relief valve 77 is repeated each time the hydraulic oil pressure in the first oil chamber 40 further increases and reaches a predetermined pressure with an increase in the steering torque, and the steering reaction force is moderate. As the pressure rises, the pressure in the connecting oil passage 66 rises.

In the above two embodiments, hydraulic oil is used as the hydraulic fluid, but other incompressible liquids can naturally be used. In this embodiment, the present invention is applied to a power steering device. However, it is naturally possible to use the present invention for a power assist device.

7 to 9 show a pressure control device according to another embodiment of the present invention.

In the present embodiment, a pressure-regulating oil pump 1 for pumping hydraulic oil from an oil reservoir 53 to the first oil chamber 40 is provided in a pressure-regulating oil passage 167 facing the first oil chamber 40. The electric motor 169 that drives the JE pump 168 is based on a detection signal from a vehicle speed sensor 100 that detects the vehicle speed. The chamber 40 is driven via the controller 17 1 so that the inside of the chamber 40 has a high pressure. In the middle of the pressure control oil passage 16 7 The oil drain 17 2 connected to the oil reservoir 5 3 branches, and a throttle 1 7 3 is interposed in the oil drain 17 2.

The sliding contact between the cylinder 11 and the housing 24 and the valve port 128 is made up of a supply / discharge oil passage 166, an oil discharge passage 15 As shown in FIG. 7, a plurality of annular grooves for communicating the supply passage 60, the pressure regulating oil passage 167, and the drainage passage 172 are formed in a sealed state.

In the present embodiment, when the spool 38 is pushed into the first oil chamber 40 along with the movement of the plunger 54, the hydraulic pressure in the first oil chamber 40 increases, and the steering reaction accompanying this is increased. The force acts on the input shaft 21 side from the drive pin 58 side via the spool operation lever 30 and unless the steering torque is increased, the spool 38 is pushed back to the right in FIG. The oil chamber 44 and the third oil chamber 45 are shut off. That is, the rising tendency of the hydraulic pressure supplied from the second oil chamber 44 to the power cylinder via the third oil chamber 45 is set so as to correspond to the hydraulic pressure of the first oil chamber 40. Has become.

Further, in the present embodiment, the controller 17 1 controls the discharge flow rate of the pressure-regulating oil pump 16 8 via the electric motor 16 9 based on the detection signal from the vehicle speed sensor 17 The larger the pressure is, the higher the oil pressure in the first oil chamber 40 becomes. Therefore, as shown in FIG. 9, which shows the relationship between the steering torque applied to the steering shaft 26 and the pressure of the hydraulic oil in the third oil chamber 45, the third oil chamber 45 The starting point of the hydraulic pressure supplied to the power cylinder via the motor shifts to the point where the steering torque is smaller, and steering in a stopped state, so-called stationary operation, etc., can be performed more easily than before.

In the above-described embodiment, the pressure in the first oil chamber 40 is adjusted using the pressure adjusting oil pump 168. However, the oil pressure in the first oil chamber 40 is adjusted without using the oil pump. It is also possible to adjust the pressure.

10 and 11 show still another embodiment of the present invention. In this embodiment, in the middle of the oil supply / drain passage 266, there are branch oil passages 278L and 278R communicating with the first oil chambers 40L and 4OR. 7 and 8) are formed. In the middle of the branch oil passages 2 780 L and 278 R, the controller 27 1 is controlled based on information from the vehicle speed sensor 2 70. Through the passage cross section The variable apertures 2779L and 2779R (sometimes simply described as 2779) that can be changed are incorporated.

Other configurations are the same as those in the previous embodiment shown in FIGS. 1 to 5. In FIGS. 10 and 11, the same members as those in the previous embodiment shown in FIGS. The same reference numerals are used.

The controller 27 1 in the present embodiment is variable so that the passage cross-sectional area of the branch oil passage 278 becomes smaller as the vehicle speed becomes lower, that is, the passage cross-sectional area of the branch oil passage 278 becomes larger as the vehicle speed becomes higher. The opening of the throttle 79 is controlled. That is, as shown in FIG. 12 showing the relationship between the steering torque applied to the steering shaft 26 and the hydraulic pressure supplied to the power cylinder in this embodiment, the oil discharge guide passage 4 When the spool 9 is closed and the spool 38 is pushed into the first oil chamber 40, the second and third oil chambers 4 4 and 4 5 communicate with each other, and the hydraulic oil from the oil pump 6 1 Starts to be supplied to the oil supply / discharge passage 266 side, and the hydraulic pressure in the oil supply / discharge passage 266 increases. Then, in response to the increase in the oil pressure, the oil pressure in the first oil chamber 40 also increases through the branch oil passage 2778, and the steering reaction force toward the input shaft 21 increases. The closer the closing of 79, the lower the oil pressure on the first oil chamber 40 side than the oil supply / discharge passage 26 6 side, so the lower the vehicle speed, the close the variable throttle 27 9 and the first oil chamber 40 To reduce the steering force during stationary operation.

It should be noted that the present invention can be implemented even if the throttle 273 formed in the middle of the oil drain passage 272 is made variable and the variable throttle 279 provided in the middle of the branch oil passage 278 is changed to a fixed throttle. The same effect as the example can be obtained. In this case, a variable throttle formed in the middle of the oil drainage passage 27 2 may be opened so that the passage cross-sectional area increases as the vehicle speed decreases.

FIG. 13 shows still another embodiment of the present invention. In this embodiment, in the middle of the supply / discharge oil passage 266, pressure sensors 380L, 380R (only 3 The sensor signal from these pressure sensors 380 is a two-port two-position switching valve 381 L, 381 R (simply, described as 381) ) Solenoids 38 2 L, 38 2 R (Sometimes described simply as 38 2 ) Is turned on and off. As shown in Fig. 14, which shows the relationship between the vehicle speed and the oil pressure in the oil supply / drain passageway 26, and the on / off state of energization to the solenoid 382, the controller 371, the vehicle speed sensor 37 0 Based on the detection signal from the sensor 380, the solenoid 382 is kept energized as the vehicle speed is higher and the oil pressure is lower, and the solenoid 382 is not energized as the vehicle speed is lower and the oil pressure is higher. The steering reaction force at the time of stationary steering is set to be small, and the steering reaction force at the time of running of the vehicle is appropriately set. Figure 15 shows the relationship between torque and hydraulic oil pressure in the power cylinder.

In other words, when the vehicle speed is high and the hydraulic pressure is low, the solenoid 382 is energized, and the two-port two-position switching valve 381 is piled on the spring force of the spring 383 and the first oil chamber 40 And the oil supply / discharge passage 266 are communicated with each other, and a hydraulic reaction force corresponding to the pressure of the hydraulic oil in the oil discharge passage 266 is generated in the first oil chamber 40. Conversely, when the vehicle speed is low and the oil pressure is high, the solenoid 382 is de-energized, and the two-port two-position switching valve 381 The spring of the 381 The branch oil path 3 8 is shut off, and the pressure in the first oil chamber 40 is maintained at the previous oil pressure. As a result, the steering reaction force accompanying the movement of the spool 38 to the first oil chamber 40 is greatly reduced. Is done.

Is the other configuration shown in the diagram? 8 are the same as those in the previous embodiment, and the same members are denoted by the same reference numerals.

FIGS. 16 to 18 show a pressure control device according to still another embodiment of the present invention. The valve rotor 428 in this embodiment is formed by a valve holder 431 and a pair of cover plates 432, 433, and is assembled so as to form a cylindrical shape as a whole. In the valve holder 431, which functions as the valve body of the present invention, a pair of stepped holes 434 and a through hole 435 extending in a direction perpendicular to the through They are bored in parallel with each other, and seal caps 436 and 437 are tightly attached to their open ends.

A pair of flanges 438 are formed in the center of the stepped hole 434, and a drainage hole is formed in the center of the stepped hole 434 located between the inner flanges 438. A chamber chamber 441 communicating with the oil reservoir 440 via the oil passage 439 is formed. The stepped hole 4 3 4 has a structure symmetrical in the longitudinal direction of the chamber chamber 4 4 1, and a small diameter portion of the stepped hole 4 3 4 in which the inner flange 4 3 The proximal ends of the spools 44 2 L and 44 2 R (which may be simply described as 44 2) are slidably fitted via O-rings 4 4 3. A conical valve body 45 that can abut the step portion 44 of the stepped hole 43 functioning as a valve seat is integrally formed at the tip of the spool 44. The inner peripheral side of the large-diameter portion of the stepped hole 4 3 4 constitutes the first oil chambers 4 4 6 L and 4 4 6 R (sometimes simply described as 4 4 6). The inner peripheral side of the small diameter portion of the stepped hole 4 3 4 located between the base end of the spool 4 4 2 and the valve body 4 4 5 is the second oil chamber 4 4 7 L, 4 4 7 R (simply , 447).

In this embodiment, the first oil chamber 446 and the second oil chamber 447 are partitioned by the step portion 4444 and the valve element 445. The present invention is not limited to this embodiment, and any other well-known structure may be employed as long as it is a structure that can shut off 46 and 447 with the spool 442.

In the second oil chamber 4 4 7, a valve body 4 4 5 is in contact with the step 4 4 4 of the stepped hole 4 3 4, and the first oil chamber 4 4 6 and the second oil chamber 4 A compression coil spring 448 for urging the spool 442 so that the communication with the port 47 is shut off is housed. An oil discharge guide passage 449 having a leading end communicating with the first oil chamber 446 is formed in the center of the spool 442 in a penetrating state along the longitudinal direction thereof.

A small diameter portion of the stepped hole 4 3 4 between the inner flange 4 3 8 and the base end of the spool 4 4 2 has a disc-shaped plunger 4 5 0 L, 4 5 OR (simply 4 5 0 The plunger 450 is provided with a cone which is slidably accommodated, and which can be closed by contacting the open end of the oil discharge guide passage 449 on the spool 442 side of the plunger 450. The shape of the pot 4 51 is protruding. Around this port 451, a plurality of communication holes 452 are formed so as to allow communication between the above-described chamber chamber 441 and the oil discharge guide passage 449 side. I have. In addition, the plunger 450 on the opposite side of the chamber chamber port 451, has a spool operation. Push lever 4 5 integrated with drive pin 4 5 3 L protruding from one end of lever 4 3 0

4 L is accommodated, and between the base end of the spool 4 42 and the plunger 450, the spool 4 42 and the plunger 450 are urged so as to be separated from each other. 5 A compression coil spring 4 that secures a gap between 1 and the opening end of the oil drainage guide passage 4 4 9 and urges the plunger 4 50 against the pressing plate 4 5 4 L 4

5 5 are interposed.

In other words, when a relative rotation difference is generated between the torsion bar spring 20 and the input shaft 21 by the operation of the steering wheel, that is, when a relative rotation difference is generated between the valve port 428 and the spool operation lever 130, The plunger 450 slides in the stepped hole 434 via the pressing plate 45.4L integral with the drive pin 45.3L, and one of the plungers 450 is connected to the compression coil spring 4488. The spool is pressed by the spring force to press the spool 442, and the port 451 blocks the oil discharge guide passage 449. Conversely, the other side of the plunger 450 moves to the inner flange 438 side, and the communication state between the chamber chamber 441 and the oil discharge guide passage 449 is ensured through the communication hole 452. In a state where there is no relative rotation difference between the torsion bar spring 20 and the input shaft 21, that is, when no relative rotation occurs between the valve rotor 4 28 and the spool operation lever 30, the chamber chamber 4 4 1 and the oil discharge guide passage 4 49 are in communication with each other through the communication hole 4 52.

In addition, the drive pin 4553 L, the press 45 5 L, the plunger 450 and the port 45 1 are operated from the steering handle via the steering shaft 26 and the spool operation lever 30 to operate the spool of the present invention. Means.

An oil pump 457 for pumping hydraulic oil from the oil reservoir 440 to the second oil chamber 447 is provided in the pressure oil supply path 456 facing the second oil chamber 447. A pressurized oil supply passageway 456 between the oil pump 457 and the second oil chamber 447 is provided with a pressure accumulator 458 in order from the second oil chamber 447 side. And a pressure switch 459 for detecting the pressure of the hydraulic oil in the pressure oil supply passage 456, and a backflow of the hydraulic fluid from the second oil chamber 447 to the oil pump 457. A check valve 460 to prevent it is incorporated. The electric motor 461 driving the oil pump 457 is operated and stopped so that the pressure oil supply passage 456 falls within a predetermined pressure range based on a detection signal from the pressure switch 549. And switch It is supposed to be.

On the other hand, in the center of the through hole 4 35, a pressing plate 45 5 R having the same shape as the above-described pressing plate 45 5 L is housed. The driving pin 4553R protruding from the other end of the operating lever 30 is integrally connected. A pair of auxiliary pistons 4 62 L and 4 62 R (sometimes simply described as 4 62) opposed to each other across the pressing plate 4 5 4 R are slidable with respect to the through hole 4 35 A compression coil spring 4 6 that presses the auxiliary piston 4 62 into the through hole 4 35 between these auxiliary pistons 4 6 2 and the seal cap 4 3 7 3 are interposed. These through-holes 435 for accommodating the compression coil springs 463 constitute auxiliary pressure chambers 464L and 464R (sometimes simply referred to as 464). are doing.

The first oil chambers 4 4 6 L, 4 4 6 R and the oil chambers 13 L, 13 R formed in the cylinder are respectively supplied and discharged oil passages 4 65 L, 4 6 5 R (simply, 4 6 5). In addition, the auxiliary oil passages 466 L and 466 R (which may be simply referred to as 466) communicating with the auxiliary pressure chambers 464 L and 464 R, respectively, are connected to the oil discharge passages 4 6 Connected to oil sump 4 4 0 via 7. A branch oil passage that branches from the supply / discharge oil passage 465 when the pressure inside the supply / discharge oil passage 465 is equal to or higher than a predetermined pressure. 4 6 8 L, 4 6 6 R (may be simply described as 4 6 8) and the auxiliary oil path 4 6 6 are connected, and the auxiliary oil path 4 6 6 and the drain oil path 4 6 7 are shut off. On the other hand, when the pressure in the oil supply / discharge passageway 465 is lower than the predetermined pressure, the auxiliary oil passageway 466 and the drainage passageway 467 are communicated and the branch oil passageway 468 is shut off as shown in the figure. It incorporates a 3-port 2-position switching valve 469 L and 469 R (sometimes simply described as 469).

That is, the hydraulic oil in the pilot oil passages 47 1 L and 47 1 R of the 3 port 2 position switching valve 469 is larger than the spring force of the spring 470 of the 3 port 2 position switching valve 469. When the pressure is low, the branch oil passage 468 is shut off and the auxiliary oil passage 466 and the drain oil passage 467 are in communication with each other. When the pressure of the hydraulic oil in the communicating pipe oil passage 4 7 1 becomes larger than the spring force of the spring 4 70 of the 3 port 2 position switching valve 4 69, the auxiliary oil passage 4 6 6 And the drain oil passage 467 is shut off, and the branch oil passage 467 communicates with the auxiliary oil passage 466 instead. Then, the hydraulic oil from the first oil chamber 4 446 is guided to the auxiliary pressure chamber 464, and to the driving pin 4 5 3 R integrated with the pressing plate 4 5 4 R via the auxiliary piston 4 62. The steering assist force is energized.

The sliding contact between the cylinder 11 and the housing 24 and the valve rotor 4 28 includes a drain oil passage 439, a pressure oil supply passage 456, and a supply / drain oil passage A plurality of annular grooves for communicating the auxiliary oil passages 466 and 465 are formed in a sealed state as shown in FIG.

Therefore, when the steering handle is operated clockwise in FIG. 17, for example, the steering force is transmitted from the steering shaft 26 to the pinion shaft 15 and the valve rotor 28 via the torsion rod spring 20, The power is also transmitted to the spool operation lever 30 integrated with the input shaft 21. If the rack bar 12 is difficult to move rightward in Fig. 16 due to frictional resistance between the road surface and the wheels (not shown), the torsion bar is The rotation angle of the spring 20 becomes smaller. For this reason, the spool operation lever 30 rotates clockwise relative to the inside of the lever holding space 29 of the valve rotor 4 28 in FIG. 17 to move the pressing plate 45 5 L integral with the drive pin 45 3 L. The plunger 450 L moves forward to the spool 44 2 L side via the plunger, and the poppet 45 1 closes the oil discharge guide passage 44 9, and is further piled by the spring force of the compression coil spring 4 48. Push the spool 4 4 2 L to the first oil chamber 4 4 6 L side. As a result, the first and second oil chambers 4 4 6 L and 4 4 7 L are in communication with each other, and the hydraulic oil from the pressurized oil supply path 4 56 6 is supplied to the oil chamber 1 via the supply and discharge path 4 65 5 L. 3 L, while the plunger 450 R moves away from the spool 44 42 R by the spring force of the compression coil spring 45 55, but the oil discharge guide passage 44 9 Since it is kept in communication with the chamber chamber 4 4 1 via 2, the pressure of hydraulic oil in the oil chamber 13 L urges the piston 14 along with the rack bar 12 to the right in Fig. 16 Is done. As a result, the pinion shaft 15 also rotates clockwise in FIG. 17 together with the valve port 428, and the relative rotation of the torsion bar spring 20 with respect to the input shaft 21 is cancelled.

When the steering wheel is operated counterclockwise in Fig. 17, when the rotation angle of the torsion bar spring 20 becomes smaller than the rotation angle of the input shaft 21, the first on the opposite side And the second oil chambers 4 4 6R and 4 4 7R are in communication with each other, and the piston 14 is urged to the left in Fig. 16 together with the rack rod 12 by the pressure of the hydraulic oil in the oil chamber 13 R. As a result, the pinion shaft 15 also rotates counterclockwise in FIG. 17 along with the valve port 1 28 to cancel the relative rotation of the torsion bar spring 20 with respect to the input shaft 21. In other words, when a relative rotation difference occurs between the torsion bar spring 20 and the input shaft 21, hydraulic fluid is supplied to one of the oil chambers 13L and 13R so as to eliminate the difference, Since the rack bar 12 is forcibly pushed in the steering direction by the oil pressure, the steering operation can be performed with a slight steering force. In this case, when the plunger 450 moves, the oil discharge guide passage 449 is closed, and the spool 442 is pushed into the first oil chamber 446. The chambers 4 4 6 and 4 4 7 are in communication with each other, and the hydraulic oil from the oil pump 4 5 7 starts to be supplied to the supply / drain oil path 4 65, but the first oil chamber 4 4 6 and the second oil chamber 4 Due to the pressure receiving area difference between the spools 4 4 2 in the oil chamber 4 4 7, a steering reaction force acts on the input shaft 2 1 side from the drive pin 4 5 3 side via the spool operation lever 30 to reduce the steering torque. Unless it increases, the spool 442 is pushed back to the drive pin 453 side, and the first oil chamber 446 and the second oil chamber 444 are shut off.

However, when the steering torque is increased by overcoming the steering reaction force from the first oil chamber 446 side, the hydraulic pressure in the supply / drain oil passage 465 becomes equal to or higher than a predetermined pressure, and at this time, the 3 port 2 The position switching valve 4 6 9 is switched so that the branch oil passage 4 6 7 communicates with the drain oil passage 4 6 8, and the hydraulic oil from the first oil chamber 4 4 6 also flows into the auxiliary pressure chamber 4 6 4 As a result, the steering assist force is urged to the driving pin 45 3 R integrated with the pressing plate 45 4 R via the catching piston 46 2, and as a result, the compression coil springs 4 4 8 and 4 63 Regardless of the load of the steering reaction force due to the difference between the spring force and the pressure receiving area of the spool 4 4 2, the hydraulic oil from the pressure oil supply passage 4 5 6 will be flushed without increasing the steering torque at that rate. The oil is supplied to the road 465 side and the hydraulic pressure rises quickly.

Therefore, as shown by the two-dot chain line in FIG. 5, the pressure of the hydraulic oil can be further increased at a predetermined steering torque or more, compared to the conventional one which is in a proportional relationship throughout, and steering in a stopped state, so-called, It can be easily deferred. When the relative rotation difference between the torsion bar spring 20 and the input shaft 21 disappears as shown in FIG. 17, that is, when the steering torque becomes 0, the plunger 450 returns to the neutral state shown in FIG. Then, the hydraulic oil in the first oil chamber 4 4 6 flows from the oil discharge guide passage 4 4 9 through the communication hole 4 5 2 through the chamber chamber 4 4 1, and the oil reservoir through the oil discharge path 4 3 9 At the same time, the 3-port 2-position switching valve 469 is switched by the spring force of the spring 470, and the auxiliary oil passage 466 and the branch oil passage 466 are shut off. Become.

In the above-described embodiment, the drive pins 45 3 are arranged at an equal distance 180 degrees apart from the center axis of the input shaft 21 in the radial direction. It is also possible to set a longer interval to the drive pin 4553R on the side.

FIG. 19 shows still another embodiment. In this embodiment, the rotation center of the input shaft 21 is larger than the length L i_ of the spool operation lever 30 from the rotation center of the input shaft 21 to the drive pin 4553 L of the plunger 450. If the length L _R of the spool control lever 30 is set longer from the drive pin 4 5 3 R to the auxiliary pin 4 on the side of the auxiliary piston 4 6 2, the drive pin 4 is set when hydraulic oil is supplied into the auxiliary pressure chamber 4 64. It is possible to increase the steering assist torque acting on the input shaft 21 via 53R. However, in this embodiment, the steering assist torque equivalent to that of the previous embodiment is obtained by setting the inner diameter of the through hole 435 small.

The other configurations are the same as those of the previous embodiment shown in FIGS.

FIGS. 20 to 24 show a pressure control device according to still another embodiment of the present invention. In this embodiment, reference numeral 530 denotes a housing as a fixed member fixed to a cylinder (gear housing) 11. In the present embodiment, there are three portions, namely, a bottom portion 530A, an intermediate portion 530B, and an upper portion 530C. A bearing 22 is provided on the upper part 5300 of the housing, and rotatably supports the input shaft 21. A spool valve type valve operating mechanism 540 is disposed in the housing middle portion 530B.

The valve operating mechanisms 540 are arranged in a symmetrical relationship to control the hydraulic pressure of the left and right working hydraulic chambers 13L and 13R.

The valve actuation mechanism 540 is an input shaft formed in the housing middle section 530B. 21 Spool valve 54, drain port 54, and spool valve 54, which are slidably disposed in holes parallel to the axis of 1 and output shaft 15, are attached in the closing direction. It mainly includes an energizing inlet spring 546, a spool valve 542, and a drain spring 548 provided between the drain port 544. The spring constant of the inlet spring 546 is set to be larger than that of the drain spring 548.

The spool valve 542 is formed with a drain hole 542 in the center and a tapered surface with the first land 542C with a seal 542B attached on the outer periphery. The formed second land 5 4 2 D is formed.

The drain poppet 544 has a conical head 544A at the end thereof to close the through hole 542A of the spool valve 542, and a flange 544 serving also as a seat of the drain spring 548 at an intermediate portion. 4B, and a drain hole 544C is formed in the flange 544B.

Further, the above-mentioned hole of the housing intermediate portion 5300B is enlarged in diameter at both ends thereof to form a working chamber 5500. The dimensions are set so that the edge portion generated by the diameter enlargement comes into contact with the above-described tapered surface of the spool valve 542.

The housing middle section 530 B is located between the cylinder ports 55 1 L and 55 1 R communicating with the working chamber 55 0 and the first land 54 2 D of the spool valve 54 2. Pump ports 52 L and 55 2 R communicating with the space to be defined are formed.

In short, the discharge side of the pump 562 driven by the motor 560 is connected to the pump ports 552 L and 552 R via the check valve 564. In this embodiment, an accumulator 566 is provided in this communication path, and the pressure operation switch 568 operates when the accumulated pressure falls below a predetermined pressure to rotate the motor 560. ing.

Next, the configuration of the movement direction changing means will be described. In this embodiment, a sleeve member 570 is provided.

The sleeve member 570 is fitted on the input shaft 21 so as to be slidable in the axial direction, and has a predetermined width as a slant guide portion inclined with respect to the axis at a middle portion thereof. Long holes 57 OA are not formed. In addition, a long groove may be formed not only in the long hole but also in the inner peripheral surface thereof. The sleeve member 570 has a guide groove or a guide slot 570B formed as an axial guide portion at a lower portion thereof, and a disc-shaped flange 5 for driving a valve actuating mechanism at an upper portion thereof. 70 C is formed.

A drive pin 572 formed on the input shaft 21 is engaged with the long hole 570A of the sleeve member 570, and a pinion shaft 18 as an output shaft is engaged with the guide groove 570B. The guide bin 574 fixed to the connector is engaged.

Thus, the above-mentioned disc-shaped flange 570C is provided at the rear end portions 544DL and 544D of the left and right drain poppets 544 of the valve operating mechanism 540 arranged symmetrically with the aforementioned line. It is arranged in a form sandwiched by DR.

In the embodiment having such a configuration, the steering force is not applied, that is, the vehicle is in a state shown in FIG. 20 when the vehicle is traveling straight in a neutral direction, and the pressure accumulated in the accumulator 566 is equal to the check valve 564 and It is held by the spool valve 542 in the closed position. At this time, the pump 562 is stopped. In the spool valve 542, the spring constant of the inlet spring 546 is larger than that of the drain spring 548, and the pressure receiving area of the pressure action surface of the lands 542C and 542 is set equal. Do not move because there is.

When the steering wheel is steered and the steering force is input to the input shaft 21, the pinion shaft 15 rotates through the torsion bar 20, and the piston rod 12 with the rack 19 formed is moved in either the left or right direction. Then, the wheels are steered.

At this time, the torsion bar 20 is twisted corresponding to the load of the rack 19, and a relative rotational displacement occurs between the input shaft 21 and the pinion shaft 15 according to the amount of twist. Therefore, the sleeve member 570 whose relative rotation with the pinion shaft 18 is prevented by the engagement between the guide bin 574 and the guide groove 570B is formed by the drive pin 57 of the input shaft 10. The input shaft 21 is moved in one of the axial directions with the relative rotation of the input shaft 21 by the engagement between the inclined shaft 2 and the elongated oblong hole 570A. For example, when the sleeve member 570 is moved upward in the axial direction, the flange 570C causes the left drain port 544L to resist the set load of the drain spring 548. And the conical head 544A closes the drain through hole 542A of the spool valve.

Then, when the relative rotation further increases, the spool valve 542 is moved against the set load of the inlet spring 546. With this movement, the tapered surface of the land 542D moves away from the edge, and the pressure accumulated in the accumulator passes through the working chamber 550 to the left hydraulic pressure chamber 522L of the cylinder 522. Introduced and assisted.

At this time, the hydraulic oil in the right-hand working hydraulic chamber 5 2 2R flows from the working chamber 5 50 R, the through hole 5 4 2 AR of the spool valve, and the through hole 5 4 4 C of the drain port to the housing 5 3 0 And drains to drain tank D via drain hole 530D.

FIG. 21 shows still another embodiment of the present invention. This embodiment differs from the previous embodiment in the movement direction changing means as described above, and the structure of the portion corresponding to the flange 570C formed integrally with the sleeve member 570 Are different.

That is, the sleeve member 670 of this embodiment has the same configuration as the sleeve member 570 except that the flange 670C has a smaller diameter than the flange 570C of the previous embodiment shown in FIG. 6 7 0 A Axial guide groove

670 B is provided.

A ring member 674 is provided so as to be relatively rotatable via a thrust bearing 672 on a flange 670C of the sleeve member 670, and the ring member 674 is a collar 6776. Thus, it is held so as to move integrally with the sleeve member 670 in the axial direction.

Further, a lever 674 A for driving a valve operating mechanism 540 is projected from the ring member 674, and the lever 674 A is neutral as in the previous embodiment shown in FIG. It is located in contact between the left and right drain ports 544 in the position. Drive pin 5 7 2 Force guide groove 6

Guide bins 574 engage with 70B, respectively, as in the previous embodiment shown in FIG.

Therefore, there is a phase difference between the input shaft 21 and the output shaft pinion shaft 15. When there is a displacement, the sleeve member 670 moves in the axial direction together with the ring member 670 as in the previous embodiment, and drives the valve operating mechanism 540. However, while the ring member 674 rotates with the pinion shaft 15 together with the sleeve member 674, the ring member 674 remains at the same rotational position due to the action of the thrust bearing 672.

Accordingly, in the present embodiment, the provision of the ring member 674 that is rotatable with respect to the input shaft 21 allows the lever 674A for driving the valve operating mechanism to be kept at a fixed position. The housing 530 can be made smaller.

FIGS. 22 to 24 show still another embodiment. This embodiment is significantly different from the previous embodiment shown in FIG. 20 in that the symmetrically arranged valve actuation mechanisms 6400 are arranged at right angles to the axis of the input shaft 10. The movement direction conversion means has been changed with the change in the arrangement.

That is, the basic operation of the valve operating mechanism 640 according to the present embodiment is the same as that of the previous embodiment shown in FIG. 20, but the configuration is slightly changed.

First, in FIG. 23, the valve operating mechanism 6400 of this example includes left and right valve bodies 641, and the valve bodies 641 are attached to the housing 630 at right angles to the axis of the input shaft 10. It is fixed facing the direction. A spool valve 642 and a drain port 644 are slidably disposed in a hole formed in the valve body 641. The spool valve 642 is urged by an inlet spring 6464 held by a plug 6447 screwed to the valve body 641, and is held at a closed position where its tapered surface contacts the edge portion. This is the same as the previous embodiment.

In this embodiment, a drain port 649 is formed in the valve body 641, instead of the drain hole 5444 of the drain port 544 in the previous embodiment shown in FIG. Others are the same as the previous embodiment shown in FIG.

Next, the housing 630 is fixed to a cylinder (gear housing) 11 formed in a substantially cylindrical shape. The movement direction changing means in this embodiment is composed of first and second sleeve members 770 and 8 fitted integrally and slidably on the input shaft 21 in the axial direction.

Contains 70. The first sleeve member 770 has a first oblong slot 77A similar to the sleeve members 570, 670 of the previous embodiment shown in FIGS. 20 and 21 and an axial guide groove 77. 0 B and a small diameter flange 770 C. The second sleeve member 870 has a second inclined long hole 87OA and a flange 870C inclined in the same direction as the first inclined long hole 870A. As shown in FIG. 24, the first and second sleeve members 770 and 870 have flanges opposed to each other, and are interposed between thrust bearings 772 by a connecting ring 774. Are linked. The connecting ring 774 is formed in an L-shaped section, and after a thrust bearing 776 is interposed between the short piece and the flange 870C of the second sleeve member 870, the long piece is formed. By screwing the portion to the flange 770C of the first sleeve member 770, the two sleeve members are connected in the axial direction while allowing relative rotation of the two sleeve members.

Further, a ring member 872 is fitted around the outer periphery of the second sleeve member 870, and the ring member 872 is provided with a lever 872A protruding outward and an inward projection. Pin 872B. The pin 872B engages with the second oblong hole 87OA formed in the second sleeve member 870, and the lever 8772A is inside the through hole 63OA of the housing 63O. The adapter between the drain port 644 L and 644 R, which are arranged opposite to the valve operating mechanism 640 described above

874 L and 874 R are arranged in contact with the interposition. The through hole 630 A allows only the rotational movement of the lever 872 A, and the movement in the axial direction is restricted.

In the above embodiment, if there is a relative displacement in the rotational direction between the input shaft 21 and the pinion shaft 15 as the output shaft, the drive pin 57 2 projecting from the input shaft 21 and the first The first slide member 7

Both 70 and the varnish slide member 870 move in the axial direction. When the second slide member 870 moves in the axial direction, the pin 872B is moved into the second oblong hole.

The member 872 engaged with 870A rotates by cam action, and the lever 872A moves the drain port 644 through the adapter 874. become.

Thus, as described in the previous embodiment, the drain port 644 and, consequently, the spool valve 642 are moved to supply pressure oil to a predetermined working hydraulic chamber to generate an assist force.

In the embodiment shown in FIGS. 20 to 24 described above, the direction of the valve operating mechanism (the axial direction of the symmetrically disposed spool valve) is arranged in parallel with the input shaft or in the direction perpendicular to the input shaft. Is different. This difference is effective because the layout can be selected in the vehicle in an advantageous manner.

Further, in the embodiment shown in FIGS. 20 to 24 described above, even if the rack (in this example, the same as the piston rod 12) is eccentric when the vehicle bounces, the output shaft and the input shaft are not connected. As long as the relative angular displacement does not occur, the valve actuating mechanism does not operate, so that there is also an effect that the steering rigidity is increased and the straight running performance of the vehicle is improved without any unnecessary assist force. In addition, since the spool valve type valve operating mechanism is disposed on the fixed member, it is possible to eliminate the need for a sealing member that may cause a problem of durability.

Claims

The scope of the claims

1. A spool slidably fitted in a valve receiving hole formed in the valve body, a first liquid chamber partitioned on one end side of the valve receiving hole by the spool, A second fluid chamber respectively formed between the spool and the hydraulic fluid supply source, and a third fluid chamber connected to the actuator.

Valve operating means for moving the spool to the first liquid chamber side and operating the second liquid chamber and the third liquid chamber so as to communicate with each other;

A working fluid passage communicating the first fluid chamber and the third fluid chamber,

A switching valve interposed in the middle of the hydraulic fluid passage to shut off a communication state between the first fluid chamber and the third fluid chamber when the pressure of the third fluid chamber becomes equal to or higher than a predetermined pressure;

A pressure control device characterized by comprising:

2. A spool slidably fitted in a valve receiving hole formed in the valve body, a first liquid chamber partitioned at one end of the valve receiving hole by the spool, the valve body and the spool. And a third liquid chamber connected to the working fluid supply source and a third liquid chamber connected to the actuator, respectively.

When the third liquid chamber becomes higher than a predetermined pressure by being interposed in the middle of the hydraulic liquid passage, the communication between the first liquid chamber and the third liquid chamber is cut off and the first liquid chamber is cut off. A switching valve connecting the liquid chamber of the above to a drainage passage branched from the hydraulic fluid passage; and

A pressure control device characterized by comprising:

3. A spool slidably fitted in a valve receiving hole formed in the valve body, a first liquid chamber partitioned on one end side of the valve receiving hole by the spool, And a hydraulic fluid supply source A second chamber connected to the second chamber, a chamber connected to the reservoir via a drainage passage, and a third chamber connected to the actuator.

The chamber is shut off from the third liquid chamber, and the spool is further moved toward the first liquid chamber so that the second liquid chamber communicates with the third liquid chamber. Valve operating means operable to

A switching valve interposed in the middle of the working fluid passage to shut off the communication between the first fluid chamber and the third fluid chamber when the third fluid chamber has a predetermined pressure or more;

A pressure control device characterized by comprising:

4. A spool that is slidably fitted in a valve receiving hole formed in the valve body, a first liquid chamber partitioned on one end side of the valve receiving hole by the spool, A second liquid chamber respectively formed between the first and second spools and connected to the hydraulic fluid supply source; a chamber chamber and an actuator which can communicate with the second liquid chamber and which are connected to the liquid reservoir via a drain passage; A third fluid chamber that connects overnight,

A pressure control device characterized by comprising:

5. A spool slidably fitted in a valve receiving hole formed in the valve body; A first liquid chamber formed between the spool and the valve body and connected to the actuator and a second liquid chamber connected to the hydraulic fluid supply source;

Spool operation means capable of operating the spool so that the first liquid chamber and the second liquid chamber communicate with each other;

Auxiliary urging means connected to the first liquid chamber via an auxiliary wave path, and capable of urging the spool operating means;

An opening / closing valve that is provided in the middle of the auxiliary liquid passage and guides the hydraulic fluid from the first liquid chamber to the auxiliary urging means when the first liquid chamber has a predetermined pressure or higher. A pressure control device characterized by the above-mentioned.

6. A spool slidably fitted in a valve receiving hole formed in the valve body,

A first liquid chamber formed between the spool and the valve body and connected to the actuator, and a chamber which can communicate with the first liquid chamber and which communicates with the liquid reservoir via a drain passage. A second fluid chamber connected to the chamber and a hydraulic fluid supply;

A spool operating means for shutting off the first liquid chamber and the chamber chamber, and further operating the spool so that the first liquid chamber and the second liquid chamber communicate with each other; An auxiliary urging means connected to the first liquid chamber through the first liquid chamber, and capable of urging the spool operating means;

An opening / closing valve that is provided in the middle of the auxiliary wave path and guides the hydraulic fluid from the first liquid chamber to the auxiliary urging means when the first liquid chamber has a predetermined pressure or more. Characteristic pressure control device.

7. A power steering device having a pair of hydraulic control valves for supplying and discharging hydraulic oil to and from a pair of cylinder chambers formed in a power cylinder, respectively, and a valve drive mechanism for operating the pair of hydraulic control valves. hand,

The hydraulic control valve includes a spool slidably fitted in a valve receiving hole formed in a valve body, and a first oil chamber partitioned by the spool at one end of the valve receiving hole. , Formed between the valve body and the spool, respectively A third oil chamber that communicates with a second oil chamber to which pressure oil from an oil pump is supplied and one of the cylinder chambers of the power cylinder; and a third oil chamber that can communicate with the third oil chamber and a drain passage. With a chamber chamber that communicates with the oil sump via

The valve drive mechanism shuts off the third oil chamber and the chamber chamber with steering, and further moves the spool to the first oil chamber side to move the second oil chamber and the third oil chamber. With the oil chamber of

A power steering device, wherein the first oil chamber is provided with hydraulic pressure adjusting means for adjusting a hydraulic pressure in the first oil chamber according to a driving state of a vehicle.

8. The hydraulic adjustment means is characterized by comprising an oil pump for supplying pressurized oil to the first oil chamber, and an oil discharge passage communicating with the first oil chamber and incorporating a throttle. The power steering device according to claim 7.

9. Hydraulic pressure adjusting means includes: a branch passage communicating the first oil chamber and the third oil chamber; valve means for narrowing or opening / closing this branch passage; and a throttle communicating and communicating with the first oil chamber. 8. The power steering apparatus according to claim 7, further comprising an oil drain in which the oil is incorporated.

10. The power steering device according to claim 7, wherein the driving state of the vehicle is a traveling speed of the vehicle.

1 1. An input shaft to which the steering force is input and an output shaft for driving the steering member are connected by a torsion bar, and a spool valve type valve is operated according to the relative rotation amount between the input shaft and the output shaft. In a power steering device having a mechanism, the spool valve type valve operating mechanism is disposed on a fixed member that rotatably supports the input shaft and the output shaft,

A movement direction converting means for converting relative rotation between the input shaft and the output shaft into movement in the axial direction of the two shafts;

Operating the valve operating mechanism by the motion direction converting means. Characteristic power steering device.

1 2. The spool valve type valve operating mechanism is arranged in parallel with the input shaft,

A sleeve member fitted with the input shaft so as to be slidable in the axial direction and inclined with respect to the axis, a guide portion in the axial direction, and a flange formed with the flange for driving the valve operating mechanism;

A drive pin protruding from the input shaft and engaging with the inclined guide portion;

The power steering according to claim 11, further comprising: a guide pin fixed to the output shaft and engaged with the axial guide portion.

13. The spool valve type valve actuating mechanism is arranged in parallel with the input shaft, and the movement direction changing means is:

A sleeve member fitted to the input shaft so as to be freely slidable and formed with an inclined guide portion inclined with respect to an axis and an axial guide portion;

A ring member including the valve operating mechanism driving lever, integrally connected to the sleeve member in the axial direction, and rotatable in the circumferential direction;

The power steering according to claim 11, further comprising a guide bin fixed to the output shaft and engaged with the axial guide portion.

14. The spool valve type valve operating mechanism is disposed at right angles to the input shaft,

The movement direction conversion means,

A first sleeve member fitted to the input shaft so as to be freely slidable and formed with a first inclined guide portion inclined with respect to an axis and a guide portion in an axial direction;

A second inclined guide portion which is rotatably and axially integrally connected to the first sleeve member and is inclined with respect to the axis; A second sleeve member in which a ring member having a pin engaged with the ring and a valve operating mechanism driving lever for driving the valve operating mechanism is fitted around the outer periphery;

A driving pin protruding from the input shaft and engaging with the first inclined guide portion; and a guide bin fixed to the output shaft and engaging with the axial guide portion. Power steering described in item 11

15. The power steering apparatus according to claim 11, wherein the fixed member is a housing fixed to a cylinder that slidably supports the steering member.