JPH04112171U - Integral power steering device - Google Patents

Abstract

(57) [Summary] (with amendments) [Purpose] To prevent damage to both the sector gear of an integral type power steering device and the stopper bolt that regulates its rotation limit. [Configuration] Gear housing 2 housing sector gear 14
The rotation angle of the stopper bolt 36 is regulated by screwing the stopper bolt 36 and abutting against the sector gear. The distal end surface 36a of the stopper bolt that abuts the sector gear is bulged into a spherical shape, and the outer circumferential portion of the distal end surface and the threaded portion screwed into the gear housing are hardened by quenching. [Effect] When the sector gear hits the stopper bolt, the bulge at the tip of the stopper bolt is recessed, increasing the contact area and reducing the surface pressure.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to an integral type power steering device.

0002

[Conventional technology]

Generally, a power steering device consists of a piston that is slidably fitted into a cylinder. The inside of the cylinder is divided into two pressure chambers, one of which is equipped with a control valve. Introduces pressure fluid controlled by switching, and operates the piston by the pressure difference between the two chambers. It is designed to apply an auxiliary force in the steering direction.

0003 In such power steering devices, necessary measures are taken to protect the steering link system. After reaching the required steering angle, a stroke limiter is installed to limit the piston stroke. It is set up.

0004 As a stroke limiter for conventional integral type power steering equipment, A rack formed on the piston and a sector gear that rotates forward and backward as the piston reciprocates. A stopper is installed at the extreme position of meshing with What has been established is known. This stopper is usually formed in the housing. It consists of a stopper bolt that is screwed into the same hole in a fluid-tight manner.

[0005]

[Problem that the idea aims to solve]

If the above stopper bolt is not hardened, it should not touch the sector gear. At times, there was a risk that the end surface of the stopper bolt would be deformed and destroyed. Also, If the entire surface of the stopper bolt is hardened to prevent deformation and failure of the tip, the sector gear will Since the area of the abutting part between the tooth surface of A and the end surface of the stopper is small, plasticity remains even under high surface pressure. The problem is that the deformation is small and cracks occur on one or both surfaces. was there.

[0006] This invention was devised to eliminate the above-mentioned drawbacks, and there is no risk of deformation or destruction. The present invention provides an integral type power steering device equipped with a stopper. .

[0007]

[Means to solve the problem]

The integral type power steering device according to the present invention has a sliding automatic structure in the cylinder. The piston fitted in the The sector gear that meshes with the gear housing, and the sector gear that is screwed into the gear housing and butts against the sector gear. and a stopper bolt that regulates the rotation angle of the stopper bolt. The tip of the bolt that hits the sector gear is bulged, and the outside of the tip is expanded. The circumferential part and the threaded part that screws into the gear housing are hardened by quenching. It is something.

[0008]

[Effect]

In the integral type power steering device according to the present invention, the sector gear is rotated. When it hits the stopper bolt, the bulge at the end of the stopper bolt will be recessed and the contact will come into contact. The contact area increases and the surface pressure decreases.

[0009]

【Example】

The present invention will be explained below with reference to illustrated embodiments. Figure 1 shows an illustration of an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view showing an integral type power steering device, showing a gear housing. A piston 6 is slidably fitted into the cylinder portion 4 of No. 2. Therefore, the inside of the cylinder 4 is divided into two pressure chambers 8 and 10. Piston 6 side A rack 12 is formed on the surface (lower surface in FIG. 1), and on this rack 12, A sector gear 14 interlocked with a steering wheel (not shown) is engaged, and the piston 6 reciprocates. It is designed to rotate forward and backward as it moves. Sector gear 1 in gear housing 2 A chamber (gear chamber) 15 in which 4 is accommodated is connected to one pressure chamber 10 via a passage 2a. It's communicating.

0010 A ball screw groove 18 is screwed into the hole 16 in the axial center of the piston 6. A worm shaft 22 is screwed together via a large number of balls 20. Gear housing above A valve housing 24 is fixed to one end of the ring 2. A stub shaft (input shaft) 26 is disposed within the worm shaft 22 so that its axis coincides with the worm shaft 22. ing. A cylindrical hole is formed on the stub shaft 26 side of the worm shaft 22. The end of the stub shaft 26 is fitted in the inside a, and both shafts 22 and 26 are connected to each other. They are connected by a torsion bar 28 inserted into a hole in the shaft core. In addition, The tab shaft 26 is linked to a steering wheel (not shown).

[0011] Inside the valve housing 24 is a valve rotor 30 that rotates integrally with the stub shaft 26. and a valve sleeve 32 formed on the worm shaft 22. A control valve 34 is housed therein.

0012 The control valve 34 is connected via the supply path 24a and the inlet port 24b. to an oil pump not shown and through a return path and outlet port not shown. A passage 32 is connected to the pressure chamber 8 on the left side in the figure via the passage 2b. They communicate with the pressure chamber 10 on the right side via b. By operating the steering wheel When this control valve 34 is switched, the oil is discharged from the pump. The pressure fluid is supplied to one of the pressure chambers 8 and 10, and the other pressure chamber is supplied to the tank. A pressure difference is created between the two chambers, and this pressure difference operates the piston 6 for operation. It is designed to provide auxiliary force in the direction of the rudder.

[0013] Gear housing 2 wall around the gear chamber 15 in which the sector gear 14 is housed A pair of stopper bolts 3 for regulating the rotation angle of the sector gear 14 in the left and right direction are provided on the surface. 6 is provided. These stopper bolts 36 are formed on the gear housing 2. screwed into the screw hole 2c, fixed with a nut 38, and fitted around the nut 38. The gear chamber 15 is kept liquid-tight by the attached O-ring 40. Stopper Bol As shown on the left side of FIG. are arranged so that they are in contact with each other.

[0014] The tips 36a of both stopper bolts 36 are bulged into a spherical shape, and the outer periphery of the tip surface The part near the tip of the threaded part that is screwed into the threaded hole 2c of the gear housing 2 from the side part Hardening is performed by induction hardening etc. for several minutes (indicated by reference numeral 36b in Fig. 2). ). The center part of the end surface 36a of the stopper bolt 36 is hardened by induction hardening. It is made softer than the hardened portion 36b on the outer periphery by reducing the vibration. In addition, sector gear 14 is carburized and quenched.

[0015] In the integral type power steering device with the above configuration, the steering wheel When the control valve is switched by the operation, one pressure chamber 8 or 10 Pressure oil from the pump is supplied to the pressure chamber 10 or 8, and the hydraulic oil in the other pressure chamber 10 or 8 is is returned to the tank, and the pressure difference between these two chambers 8 and 10 causes the piston 6 to move and Rotate the cutter gear 14.

[0016] The sector gear 14 rotates to the extreme of meshing with the rack 12 formed on the piston 6. When the position is reached, the tooth surface 14a of the sector gear 14 touches the tip surface 36 of the stopper bolt 36. When the load acts on a, the bulging center part of the stopper bolt 36 becomes concave. (see stopper bolt 36 on the right side of Figure 2), the contact area between both 14 and 36 increases. The surface pressure decreases. By reducing the surface pressure in this way, the tooth surface 14 of the sector gear 14 Abnormal surface pressure concentration occurs only at the abutting portion of the tip surface 36a of the stopper bolt 36 and the stopper bolt 36. This can prevent damage such as cracks from occurring.

[0017] Note that the dent in the stopper bolt 36 occurs due to one or two load applications, so The rotation angle of the sector gear 14 should be adjusted accordingly since the dent will be formed before the adjustment at the time of vehicle shipment. After that, it will not change over time.

[0018]

[Effect of the idea]

As described above, according to the present invention, the sector gear and the stopper bolt abut against each other. Occasionally, abnormal surface pressure concentration does not occur, and the occurrence of cracks, etc. can be prevented. Wear.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an integral power steering device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the main part of FIG. 1;

[Explanation of symbols]

2 Gear housing 4 cylinder 6 Piston 12 racks 14 Sector Gear 36 Stopper bolt 36a Tip surface of stopper bolt

Claims (1)

[Scope of utility model registration request] Claim 1: A piston that is slidably fitted into a cylinder, a rack formed on the side surface of this piston, a sector gear that meshes with this rack, and a sector gear that is threadedly engaged with a gear housing and that abuts against the sector gear. In an integral power steering device equipped with a stopper bolt that regulates the rotation angle, the stopper bolt has a protruding end surface that abuts against the sector gear, and an outer circumferential portion of the stopper bolt is screwed into the gear housing. An integral type power steering device characterized by having a threaded portion hardened by quenching.