JPS6212468A - Power steering device - Google Patents

Abstract

PURPOSE:To obtain adequate road resistance feeling in response to a car speed during traveling by connecting a control valve opened in response to a car speed during the advance travel and backward travel of a car to release the oil in an oil path to the oil path communicating a power cylinder and an oil pump. CONSTITUTION:During the advance travel or backward travel, a rotary member 71 is rotated in proportion to a car speed via a rotary shaft 65. Next at a predetermined rotating speed or more, a valve stem 82 is moved in the axial direction via a pin 72 in response to the rotating speed. Then, a recessed groove is moved, and a steel ball 116 is moved via a small steel ball to communicate oil paths 62a, 62b. The oil in a back pressure chamber 51 is released to an oil tank, the pressure of the pressure oil in the back pressure chamber 51 is decreased, a valve body 43 is moved toward the back pressure chamber 51, the pressure oil fed to a control valve 3 and a power cylinder 4 is released via a bypass path 55 to decrease the pressure of the pressure oil, thus a steering force is made heavy in response to the car speed during the advance travel and backward travel, and adequate road resistance feeling is obtained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a power steering device for a vehicle.

(Prior art) A vehicle speed-responsive valve or the like is used to make the steering heavier at high speeds, giving the driver an appropriate sense of road resistance while driving at high speeds!
f #g M , & n −'y
= 71+ '//f' Tobashira Station 1to Takeshi h
n) method has been proposed.

(Problem to be Solved by the Invention) However, conventional power steering devices are configured to increase the steering force only according to the vehicle speed when traveling forward, and therefore do not provide an appropriate sense of road resistance depending on the vehicle speed when traveling backwards. There was a problem that I couldn't get it.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a power steering device that can obtain an appropriate feeling of road resistance depending on the vehicle speed when moving forward and backward. There is something to do.

(Means for Solving the Problems) In order to achieve the above object, the present invention has an oil passage (7) communicating between the power cylinder and the oil pump that opens in accordance with the vehicle speed when the vehicle is moving forward and backward. It is characterized in that a control valve is connected to release the oil in the passage (7).

(Function) Pressure oil supplied to the power cylinder is released via the control valve depending on the vehicle speed when the vehicle is moving forward or backward, lowering the pressure of the pressure oil and making the steering heavier.

(Example) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a hydraulic circuit diagram of a power steering device.

(1) is oil pump, (2) is oil tank, (3)
is a control valve, (4) is a power cylinder, which connects the suction port (1a) of the oil pump (1) and the oil tank (2).
) are connected through an oil passage (8), and the discharge port (1b) of the oil pump (1) and the control valve (3) are connected through an oil passage (7).

The left and right cylinder chambers (12) and (13) defined by the piston (11) of the power cylinder (4) and the control valve (3) are connected through oil passages (14) and (15), ), both ends of the piston rod (17) are connected to left and right steering wheels via tie rods or the like, and a rack (18) is formed on the piston rod (17).

(21) is a steering wheel, and when the steering wheel (21) is operated, the pinion shaft (22) rolls on the rack (18) and slides on the valve body (24) of the operating valve (23). Oil chamber (2B) defined on both sides of (24)
, (27) is the valve body (31) of the control valve (3).
) are communicated with oil chambers (32) and (33) defined on both sides of the cylinder via oil passages (34) and (35), respectively.

Then, by operating the steering wheel (21), the valve body (24) is slid, and the oil chambers (2B), (27), and (32) are opened.
, (33), the valve body (31) of the control valve (3) via the oil passages (34) and (35), and the oil passage (
Power assist is performed by supplying and discharging pressure oil from the oil pump (1) to the left and right cylinder chambers (12) and (13) via (14) and (15), and (3B) in the figure is the control valve (
3) shows the oil passage connecting the operating valve (23) and the oil tank (2).

(41) is a flow control valve, and the flow control valve (41) is interposed in the oil passage (7) connecting the oil pump (1) and the control valve (3).

The flow rate control valve (41) includes a valve body (43), and an oil chamber (45) of the flow rate control valve (41) and an annular groove (43) of the valve body (43).
4B) is an oil path (
47), and also connects the oil chamber (45) and the annular groove (4
6) is connected to the oil passage (7). The back pressure chamber (51) of the flow control valve (41) is an oil passage (51) having an orifice (52a).
52) to the annular groove (46), and the back pressure chamber (51) is connected to an oil passage (54) having a relief valve (53).
When the pressure in the oil chamber (45) increases, the valve body (43) is moved to the back pressure chamber (51) side, and the oil in the oil chamber (45) is connected to the bypass path (55) through the bypass path (55). 55), control valve (3), and power cylinder (4).
) side to keep the pressure of the pressure oil constant.

(61) is a vehicle speed responsive valve, and the vehicle speed responsive valve (61) is interposed in an oil passage (62) connecting the back pressure chamber (51) of the flow control valve (41) and the oil tank (2).

Next, the vehicle speed responsive valve will be explained with reference to FIGS. 2 to 4.

Figure 2 is a cross-sectional side view of the main parts of the vehicle speed-responsive valve and final counter gear, and Figures 3 and 4 are respectively
A cross-sectional view taken along the IT-ff line is shown.

The vehicle speed responsive valve (61) meshes with the final counter gear (64) of the transmission mechanism and includes a rotating shaft (65) that rotates in proportion to the vehicle speed, and the rotating shaft (65) is connected to the lower case (6
6) and an upper case (67) to rotatably support it.

A rotating member (7) is attached to the upper part of the lower case (6B) and is connected to the rotating shaft (65) via a pin (68) and rotates together with the rotating shaft (65). A plurality of movable members (72) are incorporated so as to be freely movable in the radial direction.

A spherical engaging portion (73) is provided at the outer end of the movable member (72).
), and the movable member (72) is urged radially outward by the coil spring (74).

The rotating member (71) is covered with a rotated member (76) loosely fitted to the rotating shaft (85).

The rotated member (76) has an upper surface portion (78) on which a pin (77) is erected, and an engaging portion (73) of the movable member (72) that is vertically disposed from the upper surface portion (78). The facing cylindrical part (7
9).

The pin (77) is inserted into the guide groove (81) of the upper case (67).
), and the pin (77) is inserted into the long groove (83) of the valve shaft (82), which is installed in the upper case (67) so as to be freely movable in the axial direction, and the pin ( 77) causes the valve shaft (82) to move automatically in the axial direction.

The valve stem (82) includes a stopper (85) and an upper case (67).
), the valve stem (82) is biased to the neutral position via the step portion (86), spring bearings (87), (8B), stopper (91), and coil spring (92).

A V-shaped groove (93) is formed in the middle part of the valve stem (82), and an oil hole is formed in the upper case (67) from the direction perpendicular to the valve stem (82) facing the groove (83). (95) , (9El
), and the oil holes (95) and (9B) are each formed with a stopper (9
7) and (9B).

One of the oil holes (95) is connected to the oil path (82a) via the oil path (111), and the other oil hole (86) is connected to the oil path (112a) through the oil path (111).
) are respectively connected to the oil passages (ll12b).

Then, each of the oil holes (95) and (9B) is biased by a coil spring (114) to form a small diameter steel ball (115).
, (115) and a large-diameter steel ball (11&) are assembled, and the large-diameter steel ball (11B) is brought into close contact with the valve seat (117) and biased to close the bow (118).

The elastic force of the spring (74) A32) causes the engagement portion (73) of the movable member (72) and the cylindrical portion (
The rotating member (76) is rotated against the elastic force of the spring (92) by the frictional force due to the centrifugal force between the valve shaft (82) and the valve shaft (82).

Since this embodiment is configured as described above, when moving forward or backward, the rotating member (7 is the final counter gear (84)
), rotates in proportion to the vehicle speed via the rotating shaft (65), and rotates the valve stem (82) in the axial direction via the pin (77) according to the rotational speed at a predetermined rotational speed or higher when moving forward or backward. Automatically, the concave groove (93) moves and the small diameter steel ball (
115), a large diameter steel ball (tte) via (115)
the boat (118),
(118) is opened and the oil passages (111) and (112) are communicated through the oil holes (95) and (9B).

Then, the oil in the back pressure chambers (51) and (7) is transferred to the oil passages (82a) and (1).
11), oil hole (95), (9B), oil passage (112)
, C62b) to lower the pressure of the pressure oil in the back pressure chamber (51), move the valve body (43) to the back pressure chamber (51) side, and release the control valve (3) and power cylinder (
4) The pressure oil supplied to the side is released through the bypass path (55), and the pressure of the pressure oil is lowered to make the steering heavier depending on the vehicle speed when moving forward and when moving backward.

In addition, in the embodiment, a control valve (121) opens depending on the vehicle speed when the vehicle is moving forward or backward to release oil from the oil passage (7).
Although the case has been described in which the control valve (121) is configured by the flow rate control valve (41) and the vehicle speed responsive valve (61), the control valve (121) is not limited to this, and may be configured by the vehicle speed responsive valve (B1) alone, for example. In this case, the oil passage (111) is directly connected to the oil passage (7).
The vehicle speed responsive valve (61) is not limited to the one in the embodiment and may be optional.

(Effects of the Invention) As is clear from the above description, according to the present invention, it is possible to obtain an appropriate sense of road resistance depending on the vehicle speed when moving forward and when moving backward.

[Brief explanation of drawings]

Figure m1 is the hydraulic circuit diagram of the power steering system, Figure 2 is the vehicle speed response valve, final power untagey, and [-
It is a sectional view taken along line III and IT-rV. In the drawings, (1) is the oil pump, (2) is the oil tank, (3) is the control valve, (4) is the power cylinder, (21) is the steering wheel, (41) is the flow control valve, and (61) is the Vehicle speed responsive valve (121) is a control valve. Patent Applicant Showa Seisakusho Co., Ltd. Patent Attorney 2 1) Yong-Buma Patent Attorney Kuni Ohashi Patent Attorney Udo Koyama Patent Attorney No 1) Shigeru Figure 2

Claims (1)

[Scope of Claims] In a power steering device that performs power assist by supplying and discharging pressure oil from an oil pump to and from a power cylinder by operating a control valve by operating a handle, an oil passage (7) that communicates between the power cylinder and the oil pump is provided. A power steering device characterized in that a control valve is connected to the oil passageway (7) which opens in accordance with the vehicle speed when the vehicle is moving forward or backward.