JPH10217990A - Power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost of a power steering device by constituting a cylindrical member which constitutes a check valve by one piece and simplifying the assembly work by incorporating a ball with a diameter which is smaller than a large diameter hole part that the cylindrical member has and larger than a small diameter hole part thereof into the large diameter hole part and then caulking its opening. SOLUTION: One or a plurality of holes 15e in the radial direction are provided in stepped parts on outer peripheral faces of a thick wall part 15c and a thin wall part 15d formed close to a small diameter hole part 15b of a part which corresponds to a large diameter hole part 15a of a seat union 15 which constitutes a check valve 2 and close to an opening 8, respectively, so that hydraulic fluid can pass therethrough. A diameter of a ball 13 is smaller than a diameter of the large diameter hole part 15a and is larger than that of the small diameter hole part 15b, and a contact face 16 on which the ball 13 is seated is formed between the large diameter hole part 15a and the small diameter hole part 15b. The check valve 2 is constituted by incorporating the ball 13 into the large diameter hole part 15a of the seat union 15 and then caulking the whole periphery or a part of the opening 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power steering system in which a check valve is provided between a rubber hose provided in an introduction passage for introducing hydraulic oil from a pump and a control valve for guiding the hydraulic oil to a power cylinder. The present invention relates to a taking device.

[0002]

2. Description of the Related Art In a conventional power steering apparatus, a rubber hose is provided in an introduction passage to attenuate pulsation caused by hydraulic oil discharged from a pump. However, when the vehicle travels on an uneven road surface, the rubber hose expands and allows the reverse flow of the hydraulic oil due to the reverse input (so-called kickback) from the steered wheels. As a result, the power cylinder is activated by the kickback input, and a so-called steering wheel is generated.

In order to solve the above problem, the present applicant has filed Japanese Patent Application No. 8-295468. Figure 1
3 will be described. The hydraulic oil discharged from the pump 1 is
It passes through a rubber hose 6 arranged in the introduction passage and flows into a pressure port 10 a formed in the gear housing 10. The hydraulic oil flowing into the pressure port 10a is introduced into each cylinder chamber of the power cylinder 4 by a control valve 3 operated by a handle (not shown).

The control valve 3 includes an inner member 3a and an outer member 3b. The inner member 3a is connected to a handle (not shown), and the outer member 3b is connected to a rack shaft 12 via a pinion 11. The rack shaft 12 extends through the power cylinder 4. The piston 7 provided on the rack shaft 12 divides the power cylinder 4 into right and left chambers.

In the control valve 3, an inner member 3a and an outer member 3b are relatively rotated by steering a handle (not shown). At this time, the hydraulic oil discharged from the pump 1 is introduced into one chamber of the power cylinder 4 and the other chamber is connected to the reservoir 5, thereby moving the rack shaft 12 connected to unillustrated steering wheels. The steering force is assisted by these actions.

In the power steering apparatus having the above structure, the check valve 2 is provided in the pressure port 10a formed in the gear housing 10, thereby preventing the hydraulic oil from flowing backward when kickback is input, and I try not to be caught.

[0007]

However, in the prior art, as shown in FIG. 14, the check valve 2 composed of the ball 13, the cup-shaped tubular body 14 and the seat union 15 Is assembled into the tubular body 14, and a sheet union 15 is press-fitted into the tubular body 14. Therefore, the check valve 2 requires a difficult press-fitting operation and requires a large number of parts, resulting in high cost and a problem that the overall shape cannot be made compact.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a pump, a rubber hose provided in an introduction passage for introducing hydraulic oil from the pump, and a steering wheel which is operated by steering the handle. In a power steering apparatus provided with a control valve for guiding hydraulic oil to a power cylinder and a check valve provided between the rubber hose and the control valve, the check valve has a large-diameter hole portion and a small-diameter A cylindrical member having a hole, and a ball having a diameter smaller than the large-diameter hole and larger than the small-diameter hole, and having the opening formed after the ball is assembled in the large-diameter hole. It is characterized by being closed.

[0009]

Embodiments of the present invention will be described with reference to the drawings. A first embodiment is shown in FIGS. Since the entire configuration of the power steering device shown in FIG. 1 is the same as that of the conventional one, only the same reference numerals are given and the detailed description is omitted.

In the power steering apparatus shown in FIG. 1, a check valve 2 is provided in a pressure port 10a formed in the gear housing 10. 2 to 4 show enlarged views of the check valve 2. FIG. As shown in FIG. 2, the check valve 2 includes a ball 13, a large-diameter hole 15a and a small-diameter hole 15 in the axial direction.
b.

The large-diameter hole 15a of the seat union 15
Is thicker than the small diameter hole 15b.
As for c, thin portions 15d are respectively formed from the opening portions 8, and a step portion is formed on the outer peripheral surface thereof.
One or more radial holes 15e are provided in this step so that hydraulic oil can pass through. The ball 13 has a diameter smaller than the diameter of the large-diameter hole 15a of the seat union 15 and larger than the diameter of the small-diameter hole 15b. Further, the seat union 15 has a contact surface 16 on which the ball 13 sits between the large-diameter hole 15a and the small-diameter hole 15b. The check valve 2 is formed by caulking the entire circumference or a part of the opening 8 after the ball 13 is assembled into the large-diameter hole 15a of the seat union 15.

[0012] The check valve 2 having the above-described structure is used for the flare nut 17.
To be fixedly installed in the pressure port 10a. This fixed state is shown in FIG. 3 and FIG.
As shown in FIGS. 3 and 4, a space 9 through which the hydraulic oil passes is formed between the periphery of the thin portion 15 d and the hole of the pressure port 10 a. During normal running, as shown in FIG. 3, the hydraulic oil discharged from the pump 1 is supplied to the small-diameter hole 15.
b, the large-diameter hole 15a, the radial hole 15e, and the space 9 flow in this order to the control valve 3.

Next, the operation when a kickback is input will be described with reference to FIGS. As shown in FIG. 5, the rack shaft 12 connected to the steered wheels (not shown) is forcibly moved to one side by the kickback input, and the piston 7 provided on the rack shaft 12 To move. The movement of the rack shaft 12 causes the pinion 1
Since the outer member 3b of the control valve 3 connected to the rack shaft 12 via 1 rotates, the power cylinder 4 and the pressure port 10a communicate with each other. At this time, since the hydraulic oil in the power cylinder 4 is compressed by the movement of the piston 7,
As shown in FIG. 4, the check valve 2 prevents the backflow of the hydraulic oil when the ball 12 comes into contact with the ball contact surface 16 of the seat union 15. That is, when the check valve 2 is operated, the hydraulic pressure in the power cylinder 4 becomes high, and the movement of the piston 7 (rack shaft 12), that is, kickback can be suppressed.

Next, a second embodiment will be described. In the second embodiment, as shown in FIG.
A groove 16a is formed in the ball contact surface 16 of the first embodiment. When the kickback is input and the check valve 2 is operated, a part of the hydraulic oil squeezed by the groove 16a formed in the contact surface 16 flows backward. The partial backflow of the hydraulic oil is allowed by the expansion of the rubber hose 6.

In the second embodiment, by releasing a part of the hydraulic oil in this way, when the kickback input is large, for example, when riding on a curb, the power cylinder 4 and the control valve It is possible to prevent the oil pressure in the pump 3 from excessively increasing, and thereby prevent the oil pressure of the pump 1 from increasing to the relief set pressure. Therefore, it is not necessary to increase the pressure resistance of the power steering device so much.

FIGS. 7 to 9 show a third embodiment.
In the third embodiment, the sheet union 15 is formed with one or a plurality of communication holes 15f that communicate the large-diameter hole 15a and the small-diameter hole 15b.
Ring 18 is press-fitted so as to close 5f. When a predetermined pressure acts on the ball 13, the ring 18 is pressed by the ball 13 and moves in the seat union 15. 7 to 9, the flare nut 17 is omitted.

According to the above configuration, when a relatively small kickback is input (the check valve 2 at this time is shown in FIG. 8), the hydraulic oil cannot flow backward, and the steering wheel is completely suppressed. be able to. When a large kickback is input (the check valve 2 at this time is shown in FIG. 9), the ring 18 moves rightward in FIG. Opens, and the hydraulic oil flows backward. Therefore, the power steering device does not exceed the pressure resistance limit.

Fourth to sixth embodiments are shown in FIGS. Once a large kickback is input, the communication hole 15f is in a communication state in the third embodiment, but can be returned to the original state in the fourth to sixth embodiments. ing. In addition, the fourth to sixth
In the embodiment, only the check valve 2 is illustrated. In the fourth embodiment, as shown in FIG. 10, instead of the ring 18 in the third embodiment, a spring 19 and a ring member 20 urged by the spring 19 so as to slide in the seat union 15 are used. And the ring member 20 is connected to the communication hole 15f.
And a circlip 21 that is positioned to close the circlip.

In the fifth embodiment, as shown in FIG. 11, a bellows body 22 made of an elastic material such as resin is used instead of the spring 19 in the fourth embodiment. In the sixth embodiment, as shown in FIG. 12, instead of the ring 18 in the third embodiment, a ring member 23 made of an elastic material such as rubber or resin is used to cover the communication hole 15f.

According to the fourth to sixth embodiments, only when a large kickback is input, the communication hole 15f communicates and the hydraulic oil flows backward. When the input is made, the hydraulic oil cannot flow backward, so that the steering wheel can be completely suppressed. Therefore, the power steering device does not exceed the pressure resistance limit. Further, the check valve 2 can return to the original state even after a large kickback is input.

[0021]

According to the power steering apparatus of the present invention, it is possible to reduce the number of parts of the check valve 2 and reduce the number of parts of the check valve 2, i. The cost can be reduced by making pieces and simplification of the assembling work, and the whole shape can be made compact.

[Brief description of the drawings]

FIG. 1 is an overall view showing a first embodiment of the present invention.

FIG. 2 is a view showing a check valve according to the first embodiment of the present invention.

FIG. 3 is a view showing a normal running state of FIG. 1;

FIG. 4 is a diagram illustrating a kickback input of FIG. 1;

FIG. 5 is a hydraulic circuit diagram of FIG.

FIG. 6 is a diagram illustrating a main part of a check valve according to a second embodiment of the present invention.

FIG. 7 is a view showing a check valve according to a third embodiment of the present invention.

FIG. 8 is a diagram showing a time when a small kickback is inputted in FIG.

FIG. 9 is a diagram illustrating a state when a large kickback is input in FIG. 7;

FIG. 10 is a view showing a check valve according to a fourth embodiment of the present invention.

FIG. 11 is a view showing a check valve according to a fifth embodiment of the present invention.

FIG. 12 is a view showing a check valve according to a sixth embodiment of the present invention.

FIG. 13 is an overall view showing a conventional technique.

FIG. 14 is a view showing the check valve of FIG. 13;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump 2 Check valve 3 Control valve 4 Power cylinder 5 Reservoir 6 Rubber hose 7 Piston 10a Pressure port 13 Ball 15 Seat union

Claims (4)

[Claims] 1. A pump, a rubber hose provided in an introduction passage for introducing hydraulic oil from the pump, a control valve for guiding hydraulic oil from the pump to a power cylinder by steering a steering wheel, In a power steering device provided with a check valve provided between the control valve and the control valve, the check valve includes a cylindrical member having a large-diameter hole and a small-diameter hole, and a cylindrical member having a large-diameter hole. A power steering device comprising: a ball having a smaller diameter than the small-diameter hole, and caulking the opening after the ball is assembled into the large-diameter hole. 2. The cylindrical member has a thicker portion than the small-diameter hole portion and a thinner portion than the opening portion at a portion corresponding to the large-diameter hole portion. The power steering device according to claim 1, wherein a radial hole is formed so as to straddle the portion and the thin portion. 3. The power steering apparatus according to claim 2, wherein the tubular member is a seat union. 4. The power steering device according to claim 1, wherein the check valve allows a part of the hydraulic oil to flow backward.