JP2009202739A - Power steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce hydraulic fluid flow noise during steering without complicating the configuration of a control valve in a power steering system. <P>SOLUTION: This power steering system 10 is so configured that during steering, hydraulic fluid supplied to a supply port 30 is led to flow from a supply vertical groove 41 to one of a first port 31 and a second port 32 through a first vertical groove 31A or a second vertical groove 32A including the first or second port, and supplied to the first chamber 15A of a power cylinder 13, and also hydraulic fluid in a second chamber 15B is led to flow from the other of the first port 31 and second port 32 to a returning vertical groove 40A and a return port 40 through the first vertical groove 31A or the second vertical groove 32A including the first or second port. A control valve 50 throttling the channel area of a return channel according to a pressure difference between fluid pressure on the side of the first port 31 and fluid pressure on the side of the second port 32 is interposed in the return channel 27A on the side of a tank. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power steering apparatus including a control valve that switches and controls a hydraulic oil passage for a power cylinder.

  As shown in FIG. 7, the power steering device disclosed in Patent Document 1 has a pump-side supply channel 2 and a tank-side return channel (not shown) for steering operation in the first chamber 1 </ b> A and the second chamber 1 </ b> B of the power cylinder 1. It has a control valve 3 that performs switching control accordingly.

  The control valve 3 has a rotary pool 6 fitted in a sleeve 4 and is coaxially arranged so as to be capable of relative angular displacement according to the steering torque. The sleeve 4 has a supply port 4A connected to the pump-side supply flow path 2, and a first port 5A and a second port 5B connected to the first chamber 1A and the second chamber 1B of the power cylinder 1, respectively. It is point-symmetrically arranged around the axis. In the rotary pool 5, return ports 6A connected to the tank-side return flow path are arranged symmetrically about the central axis.

  In the control valve 3, first and second longitudinal grooves 7 </ b> A and 7 </ b> B are provided at positions including the first port 5 </ b> A and the second port 5 </ b> B on the inner surface of the sleeve 4. Further, a supply vertical groove 8A is provided at a position facing the front of the supply port 4A of the sleeve 4 at the time of neutral steering on the outer surface of the rotary pool 6, and a return vertical groove 9A at a position including the return port 6A on the outer surface of the rotary pool 6. Is provided. At this time, the first and second vertical grooves 7A and 7B on the sleeve 4 side, the supply vertical groove 8A on the rotary pool 6 side, and the return vertical groove 9A communicate with each other on both sides. The communicating part functions as a throttle part f that changes the throttle area in accordance with the relative angular displacement of the sleeve 4 and the rotary pool 6, and the change in the throttle area causes the first cylinder 5 of the power cylinder 1 to pass through the first port 5A and the second port 5B. The hydraulic pressure supplied to the first chamber 1A and the second chamber 1B is controlled.

  At the time of neutral steering shown in FIG. 6 (A), the hydraulic oil supplied to the supply port 4A is supplied to the first and second vertical grooves 7A and 7B adjacent to each other from the supply vertical groove 8A through the throttle portions f on both sides. The power cylinder 1 is distributed to each other and flows to the return vertical groove 9A and the return port 6A through the throttle portion f on the other side, and the power cylinder 1 does not operate.

At the time of turning shown in FIG. 6B, when the rotary pool 6 is rotated to the right, for example, the operating oil supplied to the supply port 4A is reduced to a throttle portion f with an increased throttle area on one side from the supply vertical groove 8A. The first vertical groove 7A flows to the first port 5A and is supplied to the first chamber 1A of the power cylinder 1, and the hydraulic fluid in the second chamber 1B is supplied from the second port 5B to the second vertical groove 7B. The power cylinder 1 is actuated by flowing through the return vertical groove 9A and the return port 6A through the throttle part f whose side throttle area is increased.
Patent 3541284

  In the control valve 3 of the power steering device, when the rotary pool 6 is rotated to the right, for example, during steering and the throttle portion f on the other side of the first vertical groove 7A is reduced, the supply port 4A passes through the supply vertical groove 8A. Thus, a part of the high-pressure hydraulic oil supplied to the first vertical groove 7A may flow through the narrow throttle portion f to the return vertical groove 9A on the low-pressure side, producing an unpleasant flow sound. Further, when the throttle part f on the other side of the second vertical groove 7B decreases, a part of the high-pressure hydraulic oil supplied from the supply port 4A to the supply vertical groove 8A passes through the narrow throttle part f to the low pressure side. May flow through the second vertical groove 7B open to the return vertical groove 9A, producing an unpleasant flow sound. The hydraulic oil supplied to the supply vertical groove 8A from the supply port 4A on the pump side is very high pressure, whereas the return vertical groove 9A connected to the return port 6A on the tank side is low pressure. Is attributed.

  In the power steering device described in Patent Literature 1, in order to reduce the above-described flow noise during turning, the throttle portions on both sides of the supply vertical groove 8A facing the supply port 4A are connected to the return port 6A. There has been proposed a structure in which the first and second longitudinal grooves 7A and 7B on the sleeve 4 side are offset in the circumferential direction so as to have a larger throttle area than the throttle portions on both sides of the groove 9A. In this case, it is difficult to process the sleeve 4 constituting the control valve 3.

  An object of the present invention is to reduce the flow noise of hydraulic oil during turning without complicating the shape of a control valve in a power steering device.

  The invention according to claim 1 has a control valve for switching and controlling the pump side supply flow path and the tank side return flow path in accordance with the steering operation in the first chamber and the second chamber of the power cylinder. The rotary pool is fitted to the two, and the two are coaxially arranged so as to be capable of relative angular displacement according to the steering torque. The sleeve has a supply port connected to the pump-side supply flow path, and a first chamber of the power cylinder. The first port and the second port connected to each of the first and second chambers are arranged point-symmetrically around the central axis, and in the rotary pool, the return port connected to the tank-side return flow path is point-symmetrical about the central axis The first and second longitudinal grooves are provided at the positions including the first port and the second port on the inner surface of the sleeve, respectively, and the slot is formed on the outer surface of the rotary pool during neutral steering. A vertical groove for supply is provided at a position facing the front of the supply port of the hub, and a vertical groove for return is provided at a position including the return port on the outer surface of the rotary pool, and during neutral steering, the hydraulic oil supplied to the supply port is From the supply longitudinal groove, the first and second longitudinal grooves are respectively passed to the return longitudinal groove and the return port. At the time of turning, hydraulic oil supplied to the supply port is supplied from the supply longitudinal groove to the first port. One of the second ports flows through the first or second longitudinal groove including the ports and is supplied to the first chamber of the power cylinder, and the hydraulic fluid in the second chamber is supplied to the first port and the second port. In the power steering apparatus configured to flow from the other side to the return vertical groove and the return port via the first or second vertical groove including those ports, the fluid pressure on the first port side is set in the tank-side return flow path. And fluid pressure on the second port side Is obtained by interposing the control valve for throttling a flow path area of said return Ri channel in response to a force difference.

  According to a second aspect of the invention, in the first aspect of the invention, the control valve is slidably incorporated in the valve housing and a main passage that is provided in the valve housing and forms an intermediate portion of the tank-side return flow path. A spool valve that adjusts the passage area of the main passage, a first pilot chamber that applies fluid pressure on the first port side to one end side of the spool valve in the valve housing, and the other end side of the spool valve in the valve housing. And a second pilot chamber for applying fluid pressure on the second port side.

(Claim 1)
(a) A control valve that restricts the flow area of the return flow path according to the pressure difference between the fluid pressure on the first port side and the fluid pressure on the second port side is interposed in the tank-side return flow path. Therefore, the control valve is operated by the pressure difference between the fluid pressure on the first port side and the fluid pressure on the second port side that is generated at the time of turning, and as a result, the channel area of the tank side return channel is reduced. The back pressure exerted on the return port increases, and the pressure in the return vertical groove connected to the return port increases. Therefore, the pressure difference between the pressure of the hydraulic oil supplied from the supply port on the pump side to the supply vertical groove and the pressure of the hydraulic oil in the return vertical groove connected to the return port on the tank side can be reduced.

  As a result, even when the rotary pool is rotated to the right, for example, when turning, and the throttle area of the throttle part f on the other side of the first vertical groove is reduced, the first vertical line is supplied from the supply port via the supply vertical groove. The flow noise generated when a part of the high-pressure hydraulic oil supplied to the groove flows through the narrow throttle portion f to the return vertical groove on the low pressure side is referred to as the pressure of the supply vertical groove and the return vertical groove. It can be reduced according to the reduction of the difference.

  Even if the throttle area of the throttle part f on the other side of the second vertical groove is reduced, a part of the high-pressure hydraulic oil supplied from the supply port to the supply vertical groove passes through the narrow throttle part f. The flow noise when passing through the second vertical groove opened in the return vertical groove on the low-pressure side can be reduced according to the reduced pressure difference between the supply vertical groove and the return vertical groove. .

  With a simple configuration in which a control valve is interposed in the tank-side return flow path, it is possible to reduce the flow noise of hydraulic oil during turning.

(Claim 2)
(b) a control valve is provided in the valve housing and forms a middle portion of the tank-side return flow path; and a spool valve that is slidably incorporated in the valve housing and adjusts the passage area of the main passage; A first pilot chamber for applying fluid pressure on the first port side to one end side of the spool valve in the valve housing, and a second pilot chamber for applying fluid pressure on the second port side to the other end side of the spool valve in the valve housing. It was made to have. Therefore, the spool valve always operates when a difference in fluid pressure between the first port side and the second port side occurs during turning, and the passage area of the main passage that forms the intermediate part of the tank side return passage is reduced. The flow path area of the return flow path can be narrowed by narrowing.

  1 is a block diagram showing a power steering device, FIG. 2 is a front view showing the power steering device, FIG. 3 is a sectional view showing a control valve, FIG. 4 is a sectional view taken along line IV-IV in FIG. FIG. 6A is a schematic diagram illustrating a neutral steering state, FIG. 6B is a schematic diagram illustrating a steered state, and FIG. 6 is a schematic diagram illustrating a conventional example.

  As shown in FIGS. 1 and 2, the hydraulic power steering apparatus 10 includes a power cylinder 13 that supports a rack shaft 12 so as to be linearly movable on a steering body 11 that is fixed to a vehicle body frame or the like by a bracket (not shown). The rack shaft 12 penetrating the power cylinder 13 is provided with a piston 14, and a first chamber 15 </ b> A and a second chamber 15 </ b> B partitioned by the piston 14 are formed inside the power cylinder 13. In the hydraulic power steering apparatus 10, the left and right tie rods 17 </ b> A and 17 </ b> B are connected to the rack shaft 12 to assist the steering force of the steering wheel 18 by the driver.

  In the hydraulic power steering apparatus 10, a valve body 21 of a control valve 20 is fixed to a steering body 11. The control valve 20 pivotally supports an input shaft 22 that rotates in conjunction with the steering wheel on the valve body 21, and is fixed to the input shaft 22 and a circular rotary pool 23 integrated with the input shaft 22, as shown in FIG. 3. A circular sleeve 24 fixed to the tip of the torsion bar 22A together with the pinion 25 is coaxially arranged so as to be capable of relative angular displacement by elastic torsional deformation of the torsion bar 22A in response to the steering torque applied to the steering wheel 18. A pump-side supply flow path 26A and a tank-side return flow path 27A are switched and connected to the first and second supply / discharge flow paths 16A and 16B connected to the first chamber 15A and the second chamber 15B, respectively, according to the steering operation. To do. In FIG. 1, 26 is a hydraulic pump, and 27 is a tank. The pinion 25 fixed to the sleeve 24 is engaged with the rack teeth 12A of the rack shaft 12.

  Specific configurations of the sleeve 24 and the rotary pool 23 of the control valve 20 are as follows (FIGS. 3 and 4).

  That is, the sleeve 24 is connected to the supply port 30 connected to the pump-side supply flow path 26A and to the first chamber 15A and the second chamber 15B of the power cylinder 13 disposed on both sides of the supply port 30, respectively. A port group of a plurality of groups (four groups in this embodiment), which is a set of three ports of the first port 31 and the second port 32, is arranged point-symmetrically around the central axis (torsion bar 22A). The first port 31 is connected to the first chamber 15A by the first supply / discharge channel 16A, and the second port 32 is connected to the second chamber 15B by the second supply / discharge channel 16B.

  Further, in the rotary pool 23, a plurality (four in this embodiment) of return ports 40 communicating with the tank-side return flow path 27A are arranged point-symmetrically around the central axis (torsion bar 22A).

  The control valve 20 is provided with a first vertical groove 31A and a second vertical groove 32A at positions including the first port 31 and the second port 32 on the inner surface of the sleeve 24, and on the outer surface of the rotary pool 23, A supply vertical groove 41 is provided at a position facing the front of the supply port 30 of the sleeve 24 during neutral steering of the steering wheel 18, and a return vertical groove 40A is provided at a position including the return port 40 on the outer surface of the rotary pool 23. .

  At this time, the first and second vertical grooves 31A and 31B on the sleeve 24 side, the supply vertical groove 41 on the rotary pool 23 side, and the return vertical groove 40A communicate with each other on both sides. The communication portion functions as a throttle portion f that changes the throttle area in accordance with the relative angular displacement between the rotary pool 23 and the sleeve 24, and the change in the throttle area causes the first port 31 and the second port 32 to change the first of the power cylinder 13. The hydraulic pressure supplied to the first chamber 15A and the second chamber 15B is controlled.

The basic operation of the control valve 20 is as follows.
(1) During neutral steering of the steering wheel 18, the supply vertical groove 41 of the rotary pool 23 faces the supply port 30 of the sleeve 24 and flows from the supply port 30 to the first port 31 in the circumferential direction of the control valve 20. The side of the supply vertical groove 41 constituting the path and the side of the first vertical groove 31A overlap, and the side of the supply vertical groove 41 constituting the flow path from the supply port 30 to the second port 32 The side portions of the second vertical groove 32A overlap. The side of the first vertical groove 31A and the side of the return vertical groove 40A overlap, and the side of the second vertical groove 32A and the side of the return vertical groove 40A overlap. Thereby, the hydraulic oil supplied to the supply port 30 is distributed to the first vertical groove 31A and the second vertical groove 32A which are adjacent to each other from the supply vertical groove 41 through the narrowed portions f on both sides, It flows to the return vertical groove 40 </ b> A and the return port 40 through the throttle part f on the other side, and then returns to the tank 27. Therefore, the power cylinder 13 does not operate.

  (2) When the steering wheel 18 is steered, for example, when the rotary pool 23 is rotated to the right from the state of FIGS. 1 and 5 to steer rightward, a flow path from the supply port 30 to the first port 31 is formed. The overlap between the supply vertical groove 41 and the first vertical groove 31A spreads, and the supply vertical groove 41 and the second vertical groove 32A constituting the flow path from the supply port 30 to the second port 32 disappear. The hydraulic oil supplied to the supply port 30 flows from the supply vertical groove 41 to the first port 31 through the throttle portion f having an increased throttle area on one side and the first vertical groove 31A, and the first chamber of the power cylinder 13 is supplied. 15A. The fluid in the second chamber 15B returns from the second port 32 to the tank 27 through the second vertical groove 32A and the return vertical groove 40A through the throttle part f having an increased throttle area on one side, and through the return vertical groove 40A. As a result, the power cylinder 13 operates to assist the steering force of the right steering.

  However, in the hydraulic power steering apparatus 10, in the control valve 20 at the time of turning, a part of the high-pressure hydraulic oil supplied from the supply port 30 to the first vertical groove 31A via the supply vertical groove 41. Is supplied to the supply vertical groove 41 from the supply port 30 and the flowing sound of the working oil flowing through the narrowing portion f narrowed on the other side of the first vertical groove 31A and the return vertical groove 40A. A part of the high-pressure hydraulic oil flows through the second vertical groove 32A opened to the return vertical groove 40A through the narrowed portion f narrowed on the other side of the second vertical groove 32A. In order to reduce the flow noise, the following configuration is provided.

  That is, the hydraulic power steering apparatus 10 includes the control valve 50 in the tank-side return flow path 27 </ b> A that extends from the return port 40 of the control valve 20 to the tank 27. The control valve 50 operates according to the pressure difference between the fluid pressure on the first port 31 (first longitudinal groove 31A) side and the fluid pressure on the second port 32 (second longitudinal groove 32A) side, and the tank side The flow passage area of the return flow passage 27A is reduced. When the control valve 50 restricts the flow area of the tank-side return flow path 27A, the back pressure exerted on the return port 40 (return vertical groove 40A) by the tank-side return flow path 27A increases, and as a result, the pump 26 side The pressure of the hydraulic oil supplied from the supply port 30 to the supply vertical groove 41 and the pressure of the hydraulic oil in the return vertical groove 40A connected to the return port 40 on the tank 27 side are reduced.

  As shown in FIG. 5, the control valve 50 is provided in the valve housing 51 and forms a middle portion of the tank-side return flow path 27 </ b> A, and is slidably incorporated in the valve housing 51. A spool valve 53 for adjusting the passage area, and a first pilot chamber 54 for applying fluid pressure on the first port 31 (first longitudinal groove 31A) side to the one end side of the spool valve 53 in the valve housing 51 via the communication passage 54A. And a second pilot chamber 55 for applying fluid pressure on the second port 32 (second longitudinal groove 32A) side via the communication path 55A to the other end side of the spool valve 53 in the valve housing 51.

  In the control valve 50, first and second compression springs 56, 57 sandwiching the spool valve 53 from both sides are loaded in the first pilot chamber 54 and the second pilot chamber 55, respectively. When there is no pressure difference between the fluid pressure on the first port 31 side and the fluid pressure on the second port 32 side, the spool valve 53 is set to the neutral position. The spool valve 53 has a small diameter at the central portion in the axial direction, and gradually increases in diameter toward both end sides, maximizes the passage area of the main passage 52 at the neutral position, and gradually increases the passage area of the main passage 52 toward both end sides. Decrease.

  Therefore, the control valve 50 has no pressure difference between the fluid pressure on the first port 31 side and the fluid pressure on the second port 32 side as shown in FIG. The spool valve 53 is set to the neutral position, the passage area of the main passage 52 is maximized, and the flow area of the pump side return flow path 27A is maximized, and the pump side return flow path 27A is connected to the return port 40 (return vertical groove 40A). ) Do not increase the back pressure.

  When the hydraulic power steering device 10 is steered to the right, for example, hydraulic oil supplied to the supply port 30 is supplied to the first chamber 15A of the power cylinder 13 via the first port 31 (first vertical groove 31A), and the power is supplied. The hydraulic oil in the second chamber 15B of the cylinder 13 returns from the second port 32 (second vertical groove 32A) to the tank 27 via the return port 40 and the tank-side return flow path 27A. At this time, as shown in FIG. 5B, the fluid pressure of the high-pressure first port 31 (first vertical groove 31A) is applied to the first pilot chamber 54 of the control valve 50, and the second pilot chamber 55 is The fluid pressure of the low-pressure second port (second vertical groove 32A) is applied, and the spool valve 53 is displaced from the neutral position toward one end side by these pressure differences, and the passage area of the main passage 52, and consequently the return to the tank side The flow path area of the flow path 27A is reduced, and the back pressure exerted on the return port 40 (return vertical groove 40A) by the tank-side return flow path 27A is increased. As the pressure difference between the fluid pressure at the first port 31 (first longitudinal groove 31A) and the fluid pressure at the second port 32 (second longitudinal groove 32A) increases, the displacement of the spool valve 53 from the neutral position increases. In addition, the passage area of the main passage 52 and the flow passage area of the tank-side return flow passage 27A are greatly reduced, and the back pressure exerted on the return port 40 (return vertical groove 40A) by the tank-side return flow passage 27A is further increased.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) The tank-side return flow path 27A is provided with a control valve 50 for reducing the flow area of the return flow path according to the pressure difference between the fluid pressure on the first port 31 side and the fluid pressure on the second port 32 side. did. Therefore, the control valve 50 is operated by the pressure difference between the fluid pressure on the first port 31 side and the fluid pressure on the second port 32 side that is generated at the time of turning, and as a result, the flow passage area of the tank side return flow passage 27A is reduced. The back pressure exerted on the return port 40 by the side return flow path 27A increases, and the pressure in the return vertical groove 40A connected to the return port 40 increases. Therefore, the pressure difference between the pressure of the hydraulic oil supplied from the supply port 30 on the pump 26 side to the supply vertical groove 41 and the pressure of the hydraulic oil in the return vertical groove 40A connected to the return port 40 on the tank 27 side can be reduced. .

  As a result, even when the rotary pool 23 is rotated to the right at the time of turning and the throttle area of the throttle portion f on the other side of the first vertical groove 31A is reduced, the supply port 30 through the supply vertical groove 41 is used. A supply vertical groove 41 is used to generate a flowing sound when a part of the high-pressure hydraulic oil supplied to the first vertical groove 31A flows through the narrow throttle part f to the low-pressure side return vertical groove 40A. And the reduction in the pressure difference of the return vertical groove 40A can be reduced.

  Further, even if the throttle area of the throttle portion f on the other side of the second vertical groove 32A is reduced, a part of the high-pressure hydraulic oil supplied from the supply port 30 to the supply vertical groove 41 is reduced in the narrow throttle portion f. The flow noise when flowing through the second vertical groove 32A that is open to the return vertical groove 40A on the low-pressure side is reduced by the pressure difference between the supply vertical groove 41 and the return vertical groove 40A. It can be reduced accordingly.

  With a simple configuration in which the control valve 50 is simply provided in the tank-side return flow path 27A, it is possible to reduce the flow noise of hydraulic oil during turning.

  (b) A control valve 50 is provided in the valve housing 51 to form an intermediate portion of the tank-side return flow path 27A, and a passage area of the main passage 52 is slidably incorporated in the valve housing 51. A first pilot chamber 54 for applying fluid pressure on the first port 31 side to one end side of the spool valve 53 in the valve housing 51, and the other end side of the spool valve 53 in the valve housing 51. And a second pilot chamber 55 for applying fluid pressure on the second port 32 side. Therefore, the spool valve 53 always operates when a difference in fluid pressure between the first port 31 side and the second port 32 side occurs during turning, and the main passage that forms the intermediate portion of the tank-side return flow path 27A. The area of the passage 52 can be narrowed, and thus the flow area of the return flow path can be reduced.

  Although the embodiment of the present invention has been described with reference to the drawings, the specific configuration of the present invention is not limited to this embodiment, and there are design changes and the like without departing from the scope of the present invention. Are also included in the present invention.

FIG. 1 is a block diagram showing a power steering apparatus. FIG. 2 is a front view showing the power steering apparatus. FIG. 3 is a sectional view showing the control valve. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 shows a control valve, (A) is a schematic diagram showing a neutral steering state, and (B) is a schematic diagram showing a steered state. FIG. 6 is a schematic diagram showing a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Power steering apparatus 13 Power cylinder 15A 1st chamber 15B 2nd chamber 20 Control valve 23 Rotary pool 24 Sleeve 26A Pump side supply flow path 27A Tank side return flow path 30 Supply port 31 1st port 31A 1st vertical groove 32 1st 2 port 32A second vertical groove 40 return port 40A return vertical groove 41 supply vertical groove 50 control valve 51 valve housing 52 main passage 53 spool valve 54 first pilot chamber 55 second pilot chamber

Claims (2)

A control valve for switching and controlling the pump-side supply flow path and the tank-side return flow path in accordance with the steering operation in the first chamber and the second chamber of the power cylinder;
The control valve fits the rotary pool in the sleeve, and both are arranged coaxially so that relative angular displacement is possible according to the steering torque.
In the sleeve, a supply port connected to the pump-side supply flow path, a first port and a second port connected to each of the first chamber and the second chamber of the power cylinder are arranged point-symmetrically around the central axis,
In the rotary pool, the return port connected to the tank side return flow path is point-symmetrically arranged around the central axis,
First and second longitudinal grooves are provided on the inner surface of the sleeve at positions including the first port and the second port, respectively, and the outer surface of the rotary pool is supplied to a position opposite to the front of the sleeve supply port during neutral steering. A vertical groove is provided at the position including the return port on the outer surface of the rotary pool,
At the time of neutral steering, the hydraulic oil supplied to the supply port is caused to flow from the supply vertical groove to the return vertical groove and the return port through the first and second vertical grooves,
At the time of turning, hydraulic oil supplied to the supply port is allowed to flow from the supply vertical groove to one of the first port and the second port through the first or second vertical groove including the port. While supplying to a 1st chamber, the hydraulic fluid of a 2nd chamber is flowed from the other of a 1st port and a 2nd port to the return vertical groove and a return port via the 1st or 2nd vertical groove containing those ports. In the power steering device configured as described above,
The tank-side return flow path is provided with a control valve that restricts the flow area of the return flow path according to the pressure difference between the fluid pressure on the first port side and the fluid pressure on the second port side. Steering device.   A main passage that is provided in a valve housing and forms an intermediate portion of the tank-side return flow path; a spool valve that is slidably incorporated in the valve housing and adjusts a passage area of the main passage; A first pilot chamber that applies fluid pressure on the first port side to one end side of the spool valve in the housing, and a second pilot chamber that applies fluid pressure on the second port side to the other end side of the spool valve in the valve housing. A power steering device comprising:

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