JPS63240470A - Power steering device - Google Patents

Abstract

PURPOSE:To improve the return characteristic of a power steering (PS) control valve, by supporting a pinion shaft to be displaceably guided by a large diametric circle, eccentrically positioned to the bottom crossing at a right angle from the axial center of the pinion shaft, in order to actuate the sliding type PS control valve by the displacement of the pinion shaft in its rack lengthwise direction. CONSTITUTION:In the case of a rack-pinion type power steering (PS) in which the PS action is performed by transmitting the lateral displacement of a pinion shaft 5 in its rack lengthwise direction to a sliding type PS control valve, a guide hole 31, which supports bearings 6, 7 of the pinion shaft 5 to be displaceably guided, forms a true circle X2 of large diameter eccentrically positioned to the bottom by a distance (e) from the axial center of the pinion shaft 5. If a handle is controlled, the pinion shaft 5 is laterally displaced along the internal peripheral surface of the guide hole 31 by load resistance for the rack. Here the pinion shaft is displaced also in the bottom direction being given a self centering function in the time of returning to the neutral condition by upper urging force of the rack by a spring, and the PS control valve enables its return characteristic to be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a rack-anthine type power steering device mainly used in automobiles.

(Prior Art) A steering device that transmits information from the steering wheel to the wheel steering arm via a mechanism consisting of a pinion and a rack is characterized by a simple structure and excellent operational response. The present applicant filed a patent application in 1982-14 as a power steering device that uses hydraulic power to assist a rough 7-pinion steering device.
The following has been proposed as No. 8612.

In other words, the pinion shaft is formed so that it moves in a direction parallel to the shaft center when the handle is operated, and by transmitting this parallel movement of the pinion shaft to the spool valve via the drive lever, the spool valve is moved close to the pinion and perpendicular to it. The device is arranged in the direction of the vehicle, thereby making the device more compact and saving installation space on the vehicle body side.The outline of this device will be explained based on FIGS. 2 and 3.

1 is a rack connected to a steering link (tie rods, etc. not shown); 2 is a pinion; 3 is a spool valve disposed perpendicular to the pinion 2; and 4 is a main body housing these components.

A pinion 2 that meshes with the rack 1 is formed integrally with a pinion shaft 5 and is supported by the main body 4 via bearings 6 and 7 provided after the pinion 2 has been disposed.

As shown in FIG. 4, the outer races 9 of the bearings 6 and 7 are inserted into oval long holes 8 in which long sleeves exist in the direction parallel to the rack 1, and the outer races 9 of the bearings 6 and 7 are inserted a predetermined distance left and right. The pinion shaft 5 is formed so that it can be displaced. however,
The pinion shaft 5 is connected to a handle (not shown), and a substitute shaft is provided on the way to absorb this displacement to the left and right.

On the other hand, the spool valve 3 is slidably housed in a sleeve portion 10 formed in the main body 4 in a direction orthogonal to the pinion shaft 5.

As shown in FIG. 3, the spool valve 3 is provided with an annular groove 11.12 that forms a pressure oil passage with the sleeve portion 10.
A control port that selectively communicates the hydraulic chamber of the power cylinder (not shown) with the pump side or the tank side in cooperation with 2)'1
3, 14, a pump boat 15, etc., are formed, and when the spool valve 3 moves from the neutral position shown in the figure to the right or left, the direction of pressure oil supply to the power cylinder is switched depending on the direction of movement.

This spool valve 3 is formed with a bottle hole 16 orthogonal to the pinion shaft 5. The drive lever 17 that connects the pin hole 16 and the pinion shaft 5 is connected to the partition wall 4A of the main body 4 that separates the spool valve 3 and the pinion shaft 5.
through an opening 18 formed in the. This drive lever 17 has a ring that fits on the pinion shaft 5. f
A support bin 20 and a drive bin 21 are protruded at symmetrical positions passing through the center of the lS 19, and a spherical support, an α portion 22, and a drive portion 23 are provided at the tips of the support bins 20 and 21, respectively.

The fulcrum part 22 of the support bottle 20 is fitted into a support hole 24 formed in the main body 4, and the drive part 23 of the drive bottle 21 is fitted into a pin hole 16 of the spool valve 3.

In the above configuration, when the pinion shaft 5 is rotated in any direction by operating a handle (not shown), the resistance of the rack 1 connected to the steering link is large, so the pinion shaft 5 is extended along the rack 1 in this rotation direction. The pinion shaft 5 is displaced by the amount allowed by the hole 8.

At this time, the drive lever 17 swings in the direction of displacement of the pinion shaft 5 after the ring portion 19 is not engaged with the pinion shaft 5, and the drive portion 23 swings about the fulcrum portion 22. As a result, the spool valve 3 is switched and the pressure oil is supplied to the power cylinder (not shown), and the pinion shaft 5
The rack 1 is driven in the rotational direction.

A neutral spring 25 biases the spool valve 3 to a neutral position, and a spring 26 biases the rack 1 upward toward the pinion 2.

(Problem to be Solved by the Invention) However, in this case, the elongated hole 8 that allows parallel movement of the pinion shaft 5 has an elliptical cross section, and the pinion shaft 5 when the spool valve 3 is in the neutral state has an elliptical cross section. Since the contact portions are vertically parallel, the spool valve 3 may not return smoothly from the switching state to the neutral state.

In addition, it is quite difficult to machine the oval long hole 8 into a machine ↑, and from the viewpoint of productivity, there is room for a few more holes.

In order to solve this problem, the present invention provides a self-centering function and improves the return of the valve by forming the elongated hole into a perfect circle with a large diameter that is eccentric in the direction perpendicular to the movement of the pinion shaft. At the same time, the processability was improved.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a rack connected to the steering wheel of a vehicle, a pinion that engages with the rack and rotates together with the steering wheel, and a pump that generates pressure from a pump. a spool valve that selectively supplies oil to the power cylinder, and supports the pinion shaft so as to be able to move in parallel along the rack by a predetermined distance via the elongated hole;
In a power steering device in which parallel movement of a pinion shaft is transmitted to a spool valve via a drive lever, the elongated hole is a perfect circle with a large diameter that is eccentric downward from the axis of the pinion shaft perpendicular to the direction of shaft displacement. Form.

(Function) In order to allow displacement of the pinion shaft, a perfect circle with an eccentric large diameter is formed below the pongee, so that the spool valve can smoothly return to its neutral state using the circular surface at the top.

(Example) Embodiments of the present invention will be described below based on the drawings.

In the embodiment shown in FIG. 1, in order to support the pinion shaft 5, a long hole (guide hole) 31 is formed by a perfect circle X2 eccentrically e downward from the axis of the pinion shaft 5.

The diameter of the perfect circle X2 is larger than that of the outer race 9, and the diameter is determined so that the pinion shaft 5 can move to the left and right by the amount necessary to switch the spool valve 3.

The other configurations are the same as those in FIGS. 2 and 3, so illustration and description will be omitted.

As the handle is fabricated and the pinion shaft 5 is rotated,
Due to the load resistance of the rack 1, the pinion shaft 5 is displaced parallel to the rack 1 along the elongated hole 31 to either side, but at the same time, the pinion shaft 5 is guided by the inner circumferential surface of the perfect circle X2 and is slightly displaced downward. Displace.

However, since the rack 1 that engages with the pinion 2 is urged upward by the spring 26, it can be displaced slightly downward, and conversely, the repulsive force of the spring 26 causes the control pulp 3 to return to the neutral state. When attempting to do so, it helps centering the pinion shaft 5.

Of course, in this case, since the top of the elongated hole 31 is formed into a mountain shape, the pinion shaft 5 can easily return, and the return of the control pulp 3 to the neutral state when the steering wheel is turned is responsive and smooth. It will be done.

(Effects of the Invention) According to the present invention, in order to allow displacement of the pinion shaft, a perfect circle with an eccentric large diameter is formed below the sleeve, so that the return of the spool valve to the neutral state is at the top. The process is carried out smoothly by utilizing the circular surface of the eel, and on top of this, the self-centering function of the pinion shaft is imparted to the eel, improving the stability and responsiveness of the control pulp. Formed as a foundation,
It has extremely good mechanical workability, improving productivity and reducing costs.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and ■-1IA in FIG.
1 [This is a sectional view of the main part corresponding to the cross section. FIG. 2 is a sectional view of the conventional device, FIG. 3 is an I-IM sectional view thereof, and FIG. 4 is the same <n-n1m sectional view. 1...Rack, 2...Pinion, 3...Control lever, 4...Main body, 5...Pinion shaft, 6
, 7...Bearing, 9...7 outer race, 17...
Drive lever, 31...long hole.

Claims (1)

[Claims] 1. A rack that is connected to the vehicle's steering wheel, a pinion that engages with the rack and rotates together with the steering wheel, and a spool valve that selectively supplies pressure oil from the pump to the power cylinder, and that has a pinion shaft. In the power steering device, the pinion shaft is supported so as to be able to move in parallel by a predetermined distance along the rack through the long hole, and the parallel movement of the pinion shaft is transmitted to the spool valve via the drive lever. A power steering device characterized by forming a perfect circle with a large diameter eccentrically downward from the axis of a pinion shaft perpendicular to the direction of shaft displacement.