JPS61160362A - Power steering device - Google Patents

Abstract

PURPOSE:To make a price inexpensive by forming a gear shaft, which forms a steering gear, in one body with a valve sleeve, which forms a control valve for oil pressure along with a valve shaft, and interposing a bearing between said shaft and sleeve. CONSTITUTION:When rotation of a valve shaft 12 puts a valve sleeve gear shaft 18 in rotation through a pin 16, a torsion bar 14 and a pin 20, a wheel is steered through engagement and the like of a steering gear by a gear tooth 18a of said shaft 18. When the torsion bar 14 is torsionally deformed due to reaction force of a road surface, relative rotation is generated between the valve shaft 12 and the gear shaft 18, that is, a valve sleeve 18, and a throttle part 10a and the like of a rotary valve 10 are put in opening/closing and assist a steering system with power. At this time, generation of rolling friction due to eccentricity between the shaft 12 and the sleeve 18b is prevented by needle bearings 22, 23. Accordingly, the valve 10 can be smoothly operated regardless of forming the gear shaft 18 in one body with the sleeve 18b.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a power steering device, and more particularly, to a power steering device.

The present invention relates to a power steering device that can rotationally displace an a-tally valve in response to a driver's steering, assist the steering force with the hydraulic pressure generated thereby, and reduce the steering force shared by a passenger.

(Prior Art) Conventionally, such a power steering device is disclosed in, for example, Japanese Utility Model Application Publication No. 57-174273. This power steering device includes a valve rotor (valve shaft) connected to the steering handle, an output shaft (gear The valve sleeve (valve sleeve) slides around the valve shaft, rotates together with the gear shaft, and together with the valve shaft constitutes a hydraulic control valve (rotary valve). ing. This is done by setting the clearance between the valve sleeve and the valve shaft to less than a few lθμ to prevent pressure leaks, and by preventing rotational friction caused by eccentricity of the valve shaft to prevent smooth relative rotation between the valve sleeve and the valve shaft. This is to prevent this from being inhibited.

(Problems to be Solved by the Invention) However, in such a conventional power steering device, the main components for operating the control valve are three members: a valve shaft, a gear shaft, and a valve sleeve. Therefore, there was a problem in that the number of parts increased, making the power steering device expensive.

Therefore, the present invention provides an inexpensive power source by integrally forming a gear shaft with teeth forming a steering gear and a valve sleeve, and interposing a bearing between the valve sleeve and the valve shaft. The purpose of this invention is to provide a steering device.

(Means for Solving the Problems) In order to solve the above problems, the power steering device according to the present invention has a valve shaft connected to a steering handle, and a torsion bar connected to the valve shaft on the same axis. A gear shaft that is connected and has teeth forming a steering gear, and a valve sleeve that rotates together with the gear shaft in relative rotatable sliding contact with the outer periphery of the valve shaft and that forms a hydraulic control valve together with the valve shaft. The gear shaft and the valve sleeve are integrally formed, and the shaft is disposed between the valve shaft and the valve sleeve.

-It is composed of a receiver.

(Function) When the steering handle is rotated, the torsion bar is torsionally deformed and relative rotation occurs between the valve shaft and the gear shaft, that is, the valve shaft and the valve sleeve, and the rotary valve operates and the pump (not shown) By supplying high oil pressure to the power cylinder and power assisting the steering system, it is possible to reduce the steering force shared by the driver. Even if rotational friction is likely to occur due to eccentricity of the valve shaft, the bearing between the valve shaft and the valve sleeve prevents rotational friction from occurring, allowing the rotary valve to operate smoothly.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. 1 and 2 are diagrams showing a power steering device according to a first embodiment of the present invention.

In FIG. 1, 10 is a rotary valve (control valve), and 12 is a valve shaft connected to a steering handle (not shown) via a steering shaft, a joint, etc. (not shown).

A hole 12a is formed in the axis of the valve shaft 12, and one end of the torsion bar 14 is fixed to the steering handle side end of the hole 12a via a pin 16 on the same axis as the valve shaft 12. .

The other end of the torsion bar 14 is connected to the hole 18c of the gear shaft 18.
The gear shaft 18 is inserted into the gear shaft 18 and connected to the gear shaft 18 by a pin 20. The gear shaft 18 has teeth 18a (in the case of a rack and pinion type, a pinion,
In the case of a recirculating ball type, a worm is formed, and a valve sleeve 18b is integrally formed at the other end. The valve sleeve 18b is connected to the valve shaft 12
A throttle portion 10a of the rotary valve 10 is formed between the valve sleeve 18b and the valve shaft 12, and the valve sleeve 18b and the valve shaft 12 open and close by rotating relative to each other. Also,
Needle bearings 22 and 23 are interposed between the valve sleeve 18b and the valve shaft 12.
As shown in the figure, when the needle bearings 22 and 23 are installed around the valve shaft 12, their maximum outer a
DN is set to be larger than the outer diameter Ds of the valve shaft 12 and smaller than the inner diameter DI of the valve sleeve 18b. 3
0 is a snap ring that is fitted onto the valve shaft 12. The valve sleeve gear shaft 18 is rotatably supported within the gear housing 27 via a bearing 25. The rotary valve 10 is a valve shaft 1 to which the steering force from the driver is input during steering.
2 and the valve sleeve gear shaft 18 through which input from the road surface is transmitted to the wheels, and a relative rotational displacement occurs between the valve sleeve and the valve shaft 12 by an amount corresponding to the amount of twist.

The gear housing 27 is formed with a supply port 27a for supplying hydraulic oil from a pump (not shown) and a discharge port 27b for discharging hydraulic oil to a reservoir tank (not shown), as well as a discharge port 27b for discharging hydraulic oil to a power cylinder (not shown). A supply port (not shown) for supplying and discharging the fluid is formed.

Next, the effect will be explained. When the driver rotates a steering handle (not shown), the valve shaft 12 rotates via a steering shaft (not shown), a joint, etc., and the valve sleeve gear shaft 18 rotates via a pin 16, a torsion bar 14, and a pin 20. Next, the teeth 18a of the valve sleeve gear shaft 18 engage the steering gear,
Steering transmission member not shown.

The wheels are steered via a joint or the like. During this steering.

Torsional deformation occurs in the torsion bar 14 due to the reaction force of the road surface, and relative rotation occurs between the valve shaft 12 and the valve sleeve gear shaft 18, that is, the valve shaft 12 and the valve sleeve 18b, and the constricted portion 1 of the rotary valve 10
0a etc. operate to open and close the throttle, and a pump (not shown) supplies high hydraulic oil to the power cylinder, thereby power assisting the steering system and reducing the steering force shared by the driver. Even if the valve shaft 12 tends to be eccentric with respect to the valve sleeve 18b during the above-mentioned steering due to processing errors, assembly errors, or lateral forces acting on the joint, the needle bearings 22 and 23 cause the valve shaft 12 and the valve sleeve to 18b can be prevented from occurring due to eccentricity. Therefore, even if the gear shaft on which the teeth 18a are formed and the valve sleeve 18b are integrally formed in this way, the rotary valve 10 can be operated smoothly.

FIG. 3 shows a power steering device according to a second embodiment of the present invention. In the first embodiment, a pair of needle bearings 22 and 23 are provided at both ends between the valve shaft 12 and the valve sleeve 18. However, the second embodiment differs in that a pair of sliding bearings 42 and 43 are interposed at both ends. The outer diameters of these slide bearings 42, 43 are machined simultaneously with the outer diameter surface of the valve shaft 12 after the slide bearings 42, 43 are press-fitted into the valve shaft 12. In this second embodiment, the occurrence of rotational friction due to eccentricity between the valve shaft 12 and the valve sleeve 18b is prevented by the bearing action with a low friction coefficient between the sliding bearings 42 and 43 and the valve sleeve 18b. I can do it. According to this second embodiment, the 5Q space for the bearing can be reduced, the wall thickness of the valve shaft 12 can be reduced, and the rotary valve 10 can be made thinner.
can be made compact.

FIG. 4 shows a power steering device according to a third embodiment of the present invention. In the first embodiment, a pair of needle bearings 22 and 23 are interposed at both ends between the valve shaft 12 and the valve sleeve 18b.
In the embodiment, a pair of sliding bearings 42.4 are provided at both ends thereof.
3 was interposed therein, whereas in this third embodiment, a sliding bearing 52 is interposed at one end on the pin 20 side of both ends, and a needle is interposed at the other end on the pin 16 side. A bearing 53 is interposed. In this third embodiment, the bearing action of the sliding bearing 52 and the needle bearing 53 can prevent rotational friction due to eccentricity between the valve shaft 12 and the valve sleeve 18b. The end of the valve sleeve 18b that is away from the bearing 25 tends to have a large radial displacement (deviation J" amount), and the rotational friction between it and the valve shaft 12 tends to increase. According to this third embodiment, in which the needle bearing 53 is used only for the rotation, the generation of such large rotational friction can be effectively prevented.

(Effects of the Invention) As explained above, according to the present invention, the gear shaft on which the teeth constituting the steering gear are formed and the valve sleeve are integrally formed, and the valve sleeve and the valve shaft are disposed between the gear shaft and the valve sleeve. By interposing the bearing, an inexpensive power steering device can be provided. Furthermore, according to the second embodiment of the present invention, the power steering device can be made compact. Furthermore, according to the third embodiment of the present invention, it is possible to effectively prevent the occurrence of large rotational friction at the end of the valve sleeve 18b facing away from the bearing 25.

[Brief explanation of drawings]

1 and 2 are diagrams showing a power steering device according to a first embodiment of the present invention, in which FIG. 1 is an upper half sectional view thereof, FIG. 2 is an enlarged view of a part in FIG. 1, FIG. 3 is an upper half sectional view showing a power steering device according to a second embodiment of the invention, and FIG. 4 is an upper half sectional view showing a power steering device according to a third embodiment of the invention. 12... Valve shaft, 14... Torsion bar, 18... Valve sleeve gear shaft (gear shaft, valve sleeve), 18a... Teeth, 18b. ...Valve sleeve. 22, 23.53... Needle bearing (bearing). 42, 43.52...Sliding bearing (bearing).

Claims (1)

[Claims] a valve shaft connected to the steering handle;
A gear shaft is connected to the valve shaft on the same axis via a torsion bar and has teeth forming a steering gear, and a gear shaft is in sliding contact with the outer periphery of the valve shaft so as to be relatively rotatable and rotates together with the gear shaft. A power steering device comprising a valve sleeve that constitutes a hydraulic control valve together with a shaft, wherein the gear shaft and the valve sleeve are integrally formed, and a bearing is interposed between the valve shaft and the valve sleeve. A power steering device characterized by: