JPH065947Y2 - Power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a power steering apparatus, and more particularly to an integral power steering apparatus in which a power cylinder and a control valve are integrally incorporated. .

[Conventional technology]

Generally, in an integral type power steering apparatus, a control valve is attached to one end of a gear housing having a cylinder part, and a pressure fluid controlled by the control valve is slidably fitted in the cylinder. It is supplied to the pressure chambers on both sides of the piston, and the piston is operated by the pressure difference between the two chambers to give an assisting force in the steering direction (Japanese Patent Laid-Open No. 57-160765, etc.).

[Problems to be solved by the invention]

In the conventional power steering apparatus as described above, one pressure chamber is adjacent to the control valve, but the other pressure chamber is located on the other end side of the gear housing, so that the passage for supplying pressure fluid is provided. Causes long pressure loss. In particular, when a large flow rate flows to the cylinder during sudden steering or when pressure fluid is supplied to both chambers of the auxiliary cylinder connected to this power steering device through the pressure chambers, the pressure loss is large,
Even if the oil pressure generated by the oil pump is high, the oil pressure in the pressure chamber of the power steering apparatus is reduced by the pressure loss, and the expected output cannot be obtained.

The present invention has been made to eliminate the above drawbacks, and an object of the present invention is to provide a power steering apparatus with little pressure loss even when a large flow rate is supplied to a cylinder.

[Means for solving problems]

The power steering apparatus according to the present invention is provided with a plurality of pressure fluid supply passages for the pressure chambers located farther from the control valve among the two pressure chambers defined by the piston in the cylinder. A plurality of passages are connected to a control valve via one annular groove.

[Action]

In the present invention, even when a large flow rate is supplied to the pressure chamber on the far side in the cylinder, the pressure loss is reduced because it flows through the plurality of passages.

〔Example〕

The present invention will be described below with reference to the illustrated embodiment. FIGS. 1 and 2 show an integral type power steering apparatus according to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view and FIG. The figure is a side view. A piston (6) is slidably fitted in the cylinder part (4) of the gear housing (2).
The inside of the cylinder (4) is divided into two pressure chambers (8) and (10) by (6). A rack (12) is formed on the side surface (bottom surface in FIG. 1) of the piston (6).
Further, a sector gear (14) interlocking with a steering wheel (not shown) is meshed with the piston (6) so that the piston (6) is rotated forward and backward as the piston (6) reciprocates.

In the hole (16) at the shaft center of the piston (6), the ball screw groove (1
8) is screwed, and the worm shaft (22) is screwed through a large number of balls (20) in the groove (18). A valve housing (24) is fixed to one end of the gear housing (2), and an input shaft (26) is arranged in the valve housing (24) with its axis aligned with the worm shaft (22). , These two axes
(22) and (26) are connected by a torsion bar (28) inserted in the hole of each axial center. The input shaft (2
6) is linked to a steering wheel (not shown).

A rotary type control valve including a valve rotor (30) that rotates integrally with the input shaft (26) and a valve sleeve (32) formed on the worm shaft (22) in the valve housing (24). (34) is housed.

Although the structure of the control valve (34) is well known in the art, the details thereof will not be described.However, the pressure chamber (10) adjacent to the control valve (34) has a diagonal passage formed in the worm shaft (22). Control valve (34) through (50)
Further, the pressure chamber (8) on the other end side of the cylinder (4), that is, on the side far from the control valve (34), has an annular groove (52) on the inner surface of the valve housing (24) and an annular groove (52). ) Communicating with two passage holes (54), (56) and gear housing (2)
It communicates with the control valve (34) through two passages (36), (38) formed around the. Then, when the control valve (34) is switched by the operation of the steering wheel, the pressure fluid discharged from the oil pump is transferred to the pressure chamber.
It is supplied to one of (8) and (10) to generate a pressure difference between the two chambers, and the piston (6) is operated by this pressure difference to apply an assisting force in the steering direction.

In addition, the two outlet holes (4
0) and (42) respectively communicate with two chambers of an auxiliary cylinder (not shown) connected to the power steering device, and pressure is applied via both pressure chambers (8) and (10). It is designed to supply fluid. Such a power steering apparatus with an auxiliary cylinder is mainly used for a vehicle having two front wheels.

In the power steering apparatus configured as described above, even when a large flow rate is supplied to the pressure chamber (8) on the side remote from the control valve (34), the inside of the plurality of passages (36), (38) is Since they flow in a dispersed manner, pressure loss can be kept small. Since the pressure loss can be reduced in this way, a sufficient output can be obtained and the flow rate of the oil pump can be reduced even if the diameter of the cylinder (4) is reduced. Further, the set pressure of the oil pump can be reduced. In addition, the responsiveness at the time of steering, the return of the steering wheel, etc. are improved. Reducing the pressure loss can also be achieved by increasing the diameter of the single passage, but in this case only a part may project outwards and interfere with other parts of the vehicle, and However, there is a problem that the entire control valve needs to be changed in design and becomes large in size, but in the case of the present embodiment, there is no such drawback. Moreover, in the annular groove (52) of the valve housing (24) to which the plurality of passages (36) and (38) are connected, although not shown in this embodiment, the control valve (34) is not shown.
Normally, 3 to 4 supply / discharge holes are opened at equal intervals in the circumferential direction from the inside, and when there is only one passage to the pressure chamber as in the conventional case, the supply / discharge holes located far from this passage are provided. The pressure fluid flowing into the passage from the hole to the pressure chamber or the pressure fluid flowing from the passage to the pressure chamber into the supply / discharge hole flows through a long distance in the annular groove. There was a problem that the pressure loss was also large, but when a plurality of passages (36), (38) were connected to the annular groove (52) as in the above-mentioned embodiment, the supply / discharge from the control valve (34) was performed. The fluid that enters the annular groove (52) through the hole passes through the passage (36), whichever is closer.
Since the fluid flows into the annular groove (52), the distance in which the fluid flows in the annular groove (52) is shortened, so that the pressure loss in the annular groove (52) can also be reduced. Moreover, by properly disposing the plurality of passages (36), (38) on the circumference of the gear housing (2), the strength of the gear housing (2) can be balanced. Further, the cylinder (4) can be reinforced, and the overall thickness can be reduced.

FIG. 3 shows another embodiment of the present invention, in which three passages (36), (38), around the gear housing (2) are provided with passages from the control valve (34) to the pressure chamber on the far side. (44) It is arranged. It goes without saying that this embodiment also has the same effects as the above embodiments.

The number of passages and their arrangement are not limited to the above,
Various configurations are possible.

[Effect of device]

As described above, according to the present invention, by providing a plurality of passages to the pressure chamber located far from the control valve, the pressure loss can be suppressed to be small even when a large flow rate is supplied to the cylinder. it can.

[Brief description of drawings]

1 and 2 show a power steering apparatus according to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a side view, and FIG. 3 is a second embodiment. It is a side view shown. (4) …… Cylinder, (6) …… Piston, (8) …… Pressure chamber far from control valve, (10) …… Pressure chamber close to control valve, (34) …… Control valve, (36 ), (38), (44) …… Aisle.

Claims (1)

[Scope of utility model registration request] 1. A pressure fluid, which is switch-controlled by a control valve that operates according to the operation of a steering wheel, is introduced into pressure chambers formed on both sides of a piston in a cylinder,
In the power steering device that applies the steering assist force through the piston, a plurality of passages are provided to the pressure chambers on the side farther from the control valve among the pressure chambers, and the passages are separated from each other. A power steering apparatus, which is arranged and connected to the control valve through one annular groove surrounding the control valve.