JPS6192963A - Hydraulic power steering device - Google Patents

Abstract

PURPOSE:To improve the damping effect of a valve spool by forming a pair of reaction liquid pressure chambers on both ends of the valve spool of a control valve device stored in the piston of the said steering device and communicating them respectively to the left and right operating liquid pressure chambers adequately. CONSTITUTION:The said steering device 10 drives and rotates an output shaft 14 having a sector 14a engaged with a rack 13a made in one body with a piston 13 inserted into a housing 11 when it is slided. A control valve device 17 controlling the feeding or discharging of the operating liquid to both operating liquid pressure chambers 15, 16 is stored in the piston 13. In this case, a control valve device 17 is formed with reaction liquid pressure chambers 27, 28 on both ends of a valve spool 21, and the reaction liquid pressure chamber 27 is communicated to the operating liquid pressure chamber 15 via an orifice 29. Furthermore, the reaction liquid pressure chamber 28 is partitioned by a plug 30 into two chambers 28a, 28b, both chambers 28a, 28b are communicated together via an orifice 31, and the chamber 28a is communicated together via an orifice 31, and the chamber 28a is communicated to the operating liquid pressure chambers 15, 16 via orifices 32, 33 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a hydraulic power steering system for a vehicle, and more particularly to a reciprocating hydraulic power steering system for moving a steering linkage of a vehicle. a cylinder device, a hydraulic pump for sending hydraulic fluid in a reservoir to the reciprocating hydraulically operated cylinder device, a passage communicating with the hydraulic pump, a 1 m passage communicating with the reservoir, and the reciprocating hydraulic The input shaft includes a valve cylinder having a passage communicating with both working hydraulic pressure chambers of the pressure-actuating cylinder, and a valve spool that is slidably housed in the valve cylinder and slid back and forth by rotation of the manual shaft. In accordance with the rotation in one direction, the hydraulic fluid from the hydraulic pump is caused to flow into one of the two hydraulic chambers of the reciprocating hydraulic hydraulic cylinder, and the hydraulic fluid in the other hydraulic chamber is caused to flow. 11 leaked into the reservoir! a control valve device that causes hydraulic fluid from the hydraulic pump to flow into the other hydraulic pressure chamber and causes hydraulic fluid in the one hydraulic pressure chamber to flow out into the reservoir in response to rotation of the input shaft in the other direction; The present invention relates to improvements in a hydraulic reaction force mechanism and a valve spool allocation mechanism in a hydraulic power steering device equipped with a hydraulic power steering device.

(Prior Art) Conventional hydraulic power steering devices of this type include, for example,
There is one described in Japanese Patent Publication No. 49-1809.

In this conventional device, as shown in FIG. 3, a pair of chambers C1 and C2 are provided at both ends of a valve spool S to which hydraulic fluid is supplied from a hydraulic pump P. Valve spool S via valve rod I7
is slid to the right, the variable throttles VOI and VO3 change to open, and the variable throttles VO2 and VO4 change to close, so that the flow from the hydraulic pump P to the chamber CI,
The hydraulic fluid sent to C2 flows from chamber CI to passage D1.
The hydraulic fluid flows into one reaction hydraulic pressure chamber E1 of the reciprocating hydraulic operating cylinder device E through the passage D2. It flows out into the reservoir R through D3, and the piston E3 slides to the left due to the hydraulic pressure difference between the two working hydraulic pressure chambers El and E2. At this time, the respective hydraulic pressures of the working hydraulic pressure chambers El and E2 are slidably fitted into the axial holes Sl and S2 of the valve spool S through orifices 01 and 02 provided in the valve spool S, and the valve cylinder The reaction force pistons Fl and F2 fixed at A are transmitted to the reaction force hydraulic pressure chambers Gl and G2 formed in the valve spool S4), and the hydraulic pressure difference between these reaction force pressure chambers Gl and G2 causes the valve spool to increase. A reaction force to the left acts on S. Further, these reaction force hydraulic pressure chambers Gl and G2 communicate with the hydraulic fluid passage only through the orifice 01.02, and when the valve spool S tries to vibrate, the hydraulic fluid passes through the orifices 01 and 02 and flows into the reaction force hydraulic pressure chamber. It goes in and out of Gl and G2, and therefore acts to prevent vibration of the valve spool S.

(Problems to be Solved by the Invention) As described above, in the prior art, the hydraulic pressure difference between the re-operating hydraulic chambers of the reciprocating hydraulic cylinder is applied to the valve spool to generate a reaction force. Since this hydraulic pressure difference is large, an appropriate reaction force cannot be obtained unless the hydraulic pressure acting area is made considerably smaller than the cross-sectional area of the valve spool S. For this reason, if an attempt is made to form such a reaction force pressure chamber under the demand for downsizing, the reaction force pressure chamber will have to be formed inside the valve spool S as shown in Fig. 3, resulting in a complicated structure. There is a problem in that manufacturing costs cannot be reduced because of the unavoidable change in technology. Moreover, since the cross-sectional area of the reaction force hydraulic pressure chamber is small, the distribution effect of the valve spool S is not good at all, and there is also the problem that the valve spool S vibrates, deteriorating the operating feeling for the driver.

Therefore, the present invention solves the above problem by making the hydraulic pressure difference that acts on the valve spool to generate a reaction force separate from the hydraulic pressure difference between the re-operating hydraulic chambers of the reciprocating hydraulic cylinder. , is the technical issue.

[Structure of the invention]

(Means for Solving the Problems) The technical means taken by the present invention to solve the above technical problems is to provide a pair of reaction pressure chambers in which both end faces of the valve spool are exposed, and to One of the reaction pressure chambers is communicated with one of the hydraulic pressure chambers of the reciprocating hydraulic cylinder through the first orifice, and the other reaction pressure chamber is connected to an axial hole of the valve spool. It is divided into two chambers by a tightly fitted plug and communicated with each other through a second orifice, and one chamber located in the valve spool is connected to one chamber of the reciprocating hydraulic cylinder through a third orifice and a fourth orifice. This means that the hydraulic pressure chamber and the other hydraulic pressure chamber are communicated with each other.

(Function) In this configuration, when the input shaft is rotated in one direction and the valve spool is slid, the hydraulic fluid from the hydraulic pump is transferred to one hydraulic chamber of the reciprocating hydraulic cylinder. At the inflow point, when the hydraulic fluid in the other hydraulic pressure chamber flows out to the reservoir, the hydraulic pressure in the one hydraulic pressure chamber is transmitted to the reaction hydraulic pressure chamber, and A portion of the hydraulic fluid sent to the second hydraulic pressure chamber flows through the third orifice into the second hydraulic pressure chamber and flows through the fourth orifice together with the hydraulic fluid in the second hydraulic pressure chamber into the reservoir. The hydraulic pressure determined by the size of the third and fourth orifices and lower than the hydraulic pressure in the reaction hydraulic pressure chamber is transmitted to the force hydraulic pressure chamber, and the hydraulic pressure between these reaction hydraulic pressure chambers is transmitted to the force hydraulic pressure chamber. The pressure difference acts on the cross-sectional area of the valve spool, producing a reaction force on the valve spool. In addition, when the input shaft is rotated in the other direction and the valve spool is slid, the hydraulic fluid from the hydraulic pump flows into the other hydraulic pressure chamber of the reciprocating hydraulic cylinder, and one hydraulic pressure is increased. When the hydraulic fluid in the chamber flows out to the reservoir, a portion of the hydraulic fluid sent to the other hydraulic chamber flows through the fourth orifice into the other reaction hydraulic chamber and through the third orifice to the one side. Since the hydraulic fluid in the hydraulic pressure chamber flows out into the reservoir together with the hydraulic fluid in the hydraulic pressure chamber, the hydraulic pressure in the reaction hydraulic pressure chamber is determined by the sizes of the third and fourth orifices and is lower than the hydraulic pressure in the reaction hydraulic pressure chamber. Pressure is transmitted, and on the other hand, there is no pressure increase in the reaction force pressure chamber, so the difference in liquid pressure between these two reaction force pressure chambers acts on the cross-sectional area of the valve spool, producing a reaction force on the valve spool. . Therefore, the double-reaction hydraulic pressure chambers have an extremely simple configuration in which the internal spaces at both ends of the valve cylinder are used, and the manufacturing cost of the device is reduced. The hydraulic pressure in both reaction pressure chambers acts on the cross-sectional area of the valve spool, and when the valve spool attempts to vibrate, the hydraulic fluid passes through the first orifice and enters and exits the reaction pressure chamber on the one hand, and the other. Since the hydraulic fluid enters and exits the reaction hydraulic pressure chamber through the second orifice into the other chamber located outside the valve spool, the vibration damping effect of the valve spool is extremely high, resulting in an extremely good operating feeling for the driver. .

(Example) Hereinafter, the present invention will be further clarified by describing examples of the present invention based on the drawings.

1 and 2, a hydraulic power steering device 10 includes a housing 11 fixed to a vehicle, and a housing 11 fixed to a vehicle.
1, an input shaft 12 rotatably disposed within the housing 11, and a piston 13 slidably and fluid-tightly fitted within the housing 11.
and an output shaft 14 having a sector 14a that meshes with a rack 13a formed on the piston 13. The input shaft 12 is connected to a steering wheel (not shown), and the output shaft 1
4 is connected to a steering link mechanism (not shown). The housing 11 and the piston 13 constitute a reciprocating hydraulic cylinder device having one hydraulic pressure chamber 15 and the other hydraulic pressure chamber 16 on both sides of the piston 13.

In the piston 13, hydraulic fluid from a hydraulic pump P (operated by the vehicle engine) flows into one of the re-operating hydraulic pressure chambers 15 and 16, and the other hydraulic fluid is transferred to a reservoir R.
a control valve device W17 for causing the flow to flow into the input shaft 12; and a nut member 18 for operating the control valve device in response to rotation of the input shaft 12. A valve pin 19 is arranged. The nut member 18 is threadedly engaged with the input shaft via a ball 2o that fits into a threaded groove formed on the outer periphery of the input shaft 12 and a threaded groove formed on the inner periphery of the nut member 18. It is assembled so that it can rotate but cannot move in the axial direction. Therefore, when the input shaft 12 is rotated, the nut member 18 rotates together with the input shaft 12. The valve pin 19 is fixed to the nut member 18, and its free end is inserted into the radial hole 21'' of the valve spool 21 of the control valve device 17.

The control valve device 17 includes a bushing 22 that is fitted into the lateral hole 13b of the valve cylinder, that is, the piston 13, and a valve spool 21 that is slidably housed within the bushing 22. . The piston 13 and the bushing 22 are provided with passages 13c and 22c that communicate with the hydraulic pump P through the hydraulic fluid inlet of the housing 11.
, iwU passages 13d and 22d communicating with the reservoir R via the hydraulic fluid outlet of the buzzing 11, and one hydraulic fluid pressure chamber 15.
passages 13e and 22e connected to im, and the other working hydraulic pressure chamber 1.
Passages 13f and 22f communicating with 6 are formed. The bush 22 further has circumferential grooves 22a and 22b on its inner circumference.
is formed. Land 2 on valve spool 21]
a, 21b, 21c, and 21d are provided, a variable aperture 23.24 is formed by the land 21b and the circumferential groove 22a, and a variable aperture 25 is formed by the land 21c and the circumferential groove 22b.
．． 26 is formed. As a result, the input shaft 12 is rotated in the direction of the arrow shown in FIG. 2', and the nut member 18 and the valve pin 19 are rotated together with the input shaft 12.
is moved to the right, the opening amount of the variable throttle 24.26 increases and the opening amount of the variable throttle 23.25 decreases, causing the hydraulic fluid from the hydraulic pump P to flow between the passage 13d and the passage 22.
d - Variable throttle 24 - Groove between lands 21b and 2IC - Passage 22e - Passage 13e to flow into one working hydraulic pressure chamber 5, while the working fluid in the other working hydraulic pressure chamber 16 flows into passage 13'-
Passage 22f - Groove between lands 21C and 21d - Variable aperture 2
6-passage 22d-passage 13d to the reservoir R, so the piston 13 slides in one direction and moves the steering linkage. When the input shaft 12 is rotated in the opposite direction, the valve spool 21 is rotated by the valve pin 19 in FIG.
is moved to the left, the opening amount of the variable diaphragm 23.25 increases, and the opening amount of the variable diaphragm 24.26 decreases.
The hydraulic fluid from the hydraulic pump P flows through the passage 13C-the passage 22C-
Variable throttle 23 - groove between lands 21a and 21b - passage 22
f - The working fluid in the working hydraulic pressure chamber 15 flows through the passage 13f into the other working hydraulic pressure chamber 16, while the working fluid in the working hydraulic pressure chamber 15 flows through the passage 13e, the passage 22e, the groove between the lands 21b and 21c, and the variable throttle 25.
As it flows out through the passage 22d-13d into the reservoir R, the piston 13 slides in the other direction, moving the steering linkage in the opposite direction.

a reaction hydraulic pressure chamber 27 in which both ends of the valve spool 21 are exposed;
2B is the housing 11. Piston 13° Valve spool 21. is formed by a bush 22, while a reaction force hydraulic chamber 2
7 communicates with the groove between the lands 21b and 21c, that is, with the hydraulic pressure chamber 15, through a first orifice 29 formed in the valve spool 22. On the other hand, the reaction force hydraulic pressure chamber 28
is divided into one chamber 28a and the other chamber 28b by a plug 30 fitted and fixed in the axial hole 21e of the valve spool 21, and a second orifice 3 formed in the plug 30.
Both chambers 28a and 28b are communicated with each other through the radial hole 21r ( Land 21b, 2
1c) and land 2]c, 2Id
They communicate with the grooves between them, that is, one side of the working hydraulic pressure chambers 15 and (
]3) The other side is connected to the hydraulic pressure chamber 16, respectively.

Therefore, the hydraulic fluid from the hydraulic pump P is supplied to the hydraulic pressure chamber 1 on one side.
5 and the hydraulic fluid in the other hydraulic pressure chamber 16 flows out to the reservoir, the hydraulic pressure in the hydraulic pressure chamber 15 on the one hand is transmitted to the reaction hydraulic pressure chamber 27 on the other hand, and 1
A portion of the hydraulic fluid sent to the third orifice 3
2 into the one chamber 28a and the fourth orifice 33.
The hydraulic pressure that is lower than the hydraulic pressure in one of the working hydraulic pressure chambers 15 is transmitted to the other reaction force hydraulic pressure chamber 28 by flowing out to the reservoir through the reaction force hydraulic pressure chamber 28, and the hydraulic pressure difference between the two reaction force hydraulic pressure chambers 27 and 28 is is valve spool 2
1, the valve spool 21 is pushed leftward in FIG. 1, and this is transmitted to the input shaft 12 as a reaction force. Further, when the hydraulic fluid from the hydraulic pump P flows into the other hydraulic pressure chamber 16 and the hydraulic fluid in the one hydraulic pressure chamber 15 flows out to the reservoir, the hydraulic fluid is sent to the other hydraulic pressure chamber 16. A portion of the hydraulic fluid flows into one chamber 28a through the fourth orifice 33, flows out through the third orifice 32 into the reservoir R, and enters the other reaction hydraulic pressure chamber 28 in the other hydraulic pressure chamber 16. A hydraulic pressure lower than the hydraulic pressure is transmitted, and on the other hand, there is no pressure increase in the reaction force hydraulic pressure chamber 27, so both reaction force hydraulic pressure chambers 27, 2
8 acts on the cross-sectional area of the valve spool 21 and presses the valve spool 21 to the right in FIG.

On the other hand, since the reaction hydraulic pressure chamber 27 communicates with the hydraulic fluid passage only through the first orifice 29, when the valve spool 21 attempts to vibrate, the hydraulic fluid passes through the first orifice 29 and flows into the reaction hydraulic pressure chamber. 27, thus providing an anti-vibration effect for the valve spool 21. On the other hand, the reaction force hydraulic pressure chamber 28
Also, since the other chamber 28b communicates with the hydraulic fluid passage only through the second orifice 30, when the valve spool 21 attempts to vibrate, the hydraulic fluid passes through the second orifice 30 and enters and exits the other chamber 28b. , the vibration prevention effect of the valve spool 21 occurs. In this way, both reaction force hydraulic pressure chambers 27 and 22 act as a so-called damper, and the hydraulic pressure of each reaction force hydraulic pressure chamber acts on the cross-sectional area of the valve spool 21, so that the vibration damping effect of the valve spool 21 is improved. is extremely high.

Although one embodiment of the present invention has been described above, the cylinder device, the control valve device, the connection structure between the input shaft and the control valve device, etc. of the present invention are not limited to the structure of the one embodiment, and the It can be changed as appropriate within the range described in .

〔Effect of the invention〕

As detailed above, according to the present invention, the configuration of the control valve device is simplified and miniaturized, the manufacturing cost is reduced, and the vibration damping effect of the valve spool is high.
This has the effect of improving the steering feel.

[Brief explanation of drawings]

Fig. 1 is a partially enlarged cross-sectional view of an embodiment of the present invention taken along line I-I in Fig. 2, Fig. 2 is a vertical cross-sectional view, and Fig. 3 is a partially enlarged cross-sectional view of a conventional device. It is a diagram. Explanation of symbols

Claims (1)

[Claims] A reciprocating hydraulic cylinder device for moving a steering linkage mechanism of a vehicle, a hydraulic pump for sending hydraulic fluid in a reservoir to the reciprocating hydraulic cylinder device, and communicating with the hydraulic pump. a valve cylinder having a passage communicating with the reservoir, a passage communicating with both working hydraulic pressure chambers of the reciprocating hydraulic actuating cylinder; and a valve spool that is slidable in a reciprocating manner, so that in response to unidirectional rotation of the input shaft, one of the two working hydraulic chambers of the reciprocating hydraulic actuating cylinder receives actuation from the hydraulic pump. The hydraulic fluid is allowed to flow in, the hydraulic fluid in the other hydraulic pressure chamber is caused to flow out into the reservoir, and the hydraulic fluid from the hydraulic pump is caused to flow into the other hydraulic pressure chamber in response to rotation of the input shaft in the other direction. and a control valve device for causing the hydraulic fluid in the one hydraulic pressure chamber to flow out to the reservoir, the hydraulic power steering device comprising: a pair of reaction hydraulic pressure chambers in which both end surfaces of the valve spool are exposed; One of these reaction hydraulic pressure chambers is communicated with the one working hydraulic pressure chamber through a first orifice, and the other reaction hydraulic pressure chamber is tightly fitted into the axial hole of the valve spool. The two chambers are divided by a plug and communicated with each other through a second orifice, and one chamber located in the valve spool is connected to the one working hydraulic pressure chamber and the other working hydraulic pressure chamber through a third orifice and a fourth orifice. Hydraulic power steering device connected to each chamber.