JP2003165454A - Power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power steering device capable of reducing noises caused by collision in a check valve when it is closed, and restraining pressure loss of hydraulic fluid, as much as possible, caused by a compression coil spring in the check valve in a valve-open condition. <P>SOLUTION: To prevent generation of a kick-back phenomena, this power steering device includes the check valve 30 which inhibits countercurrent of the hydraulic fluid from a power cylinder system to the hydraulic pump 3 side by using a flared seat 26 jointed to an inlet port forming part 14a of a valve housing 14 for accommodating a hydraulic control valve 13 as its valve body. The check valve 30 includes the valve body 31 formed out of synthetic resin and the compression coil spring 32. A plurality of passages 36 which allow the hydraulic fluid to flow between an inlet part 28a and an outlet part 28b of the check valve 30 without flowing in a diametrical direction of the compression coil spring 32 are formed at an outer part in the diametrical direction of the compression coil spring 32 and along a traveling direction of the valve body 31 in the check valve 30. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power steering apparatus used in a vehicle, which is a non-return mechanism for preventing backflow of hydraulic oil from a hydraulic actuator that generates a steering assist force to a hydraulic pump side. The present invention relates to a power steering device including a valve.

[0002]

2. Description of the Related Art Conventionally, as a power steering apparatus of this type, there is one disclosed in Japanese Patent Laid-Open No. 11-49007.
In this power steering apparatus, a check valve that prevents the pressure oil supplied to the hydraulic actuator from flowing backward to the hydraulic pump is provided in the input port of the hydraulic control valve, the output port of the hydraulic pump, or the hydraulic path. It is built into the flare nut that is inserted into the pipe joint. The check valve has a casing formed of an inner peripheral portion that forms a flow path inside the flare nut, a movable plug that is inserted into the casing, and a movable plug that closely contacts a valve seat formed in the casing. C for biasing the coil spring and the base end of the coil spring
It consists of a mold retaining ring. This check valve prevents the so-called kickback phenomenon in which the hydraulic oil supplied to the hydraulic actuator flows backward to the hydraulic pump and the steering wheel is taken by the external force applied to the wheels when the vehicle rides on a curb. To be done. In addition, since the check valve is built in the flare nut, the check valve is assembled at the same time as the flare nut is assembled. Therefore, productivity is enhanced as compared with the case where these are assembled separately.

[0003]

By the way, in the prior art described above, the collision noise generated when the movable plug (valve body) collides with the valve seat when the check valve is closed is not taken into consideration.

When the check valve opens, pressure oil (working oil) flows in from the inlet of the flare nut and flows through the gap between the outer peripheral portion of the movable plug and the peripheral portion of the casing. It passes through the coil spring from the outer side to the inner side in the radial direction and flows out from the outlet of the flare nut. At this time, the coil spring is compressed according to the amount of movement of the movable plug, and the pressure oil moves in the radial direction in the coil spring in which the pitch decreases and the flow area in the radial direction decreases as the opening degree of the check valve increases. You will pass through. Therefore, the pressure loss of the pressure oil due to the reduction of the flow area in the radial direction of the coil spring increases as the flow rate of the hydraulic oil increases and the opening degree of the check valve increases.
The increase in the pressure loss causes a decrease in responsiveness of the hydraulic actuator, and there is a difficulty in restricting the degree of freedom in designing the power steering apparatus.

Further, since the flare nut used in the power steering apparatus is a component having a small diameter passage, a C-shaped retaining ring for locking one end of the coil spring is attached to the flare nut of the flare nut. It is not easy to attach to the mounting groove formed at a position away from the end portion, and improvement of the assembling property of the retaining ring has been desired.

The present invention has been made in view of such circumstances, and the inventions according to claims 1 to 4 are:
A power steering device capable of reducing noise caused by a collision noise when the check valve is closed and capable of suppressing pressure loss of hydraulic oil due to a compression coil spring of the check valve in the open state as much as possible. The purpose is to provide. The invention according to claim 2 further aims at facilitating the assembly of the spring bearing of the check valve, and the invention according to claim 3 further facilitates the movement of the valve body of the check valve. With the aim of forming a passage for suppressing the pressure loss of the hydraulic oil with a simple structure using the guide piece, the invention according to claim 4 is further provided with a spring holder fixed to the valve body. It is an object of the present invention to suppress a pressure loss of hydraulic oil due to a compression coil spring in a check valve having a.

[0007]

According to a first aspect of the present invention, there is provided a hydraulic pump having a discharge port forming portion in which a discharge port for discharging hydraulic oil is formed, and a hydraulic pump operated by hydraulic pressure of the hydraulic oil. A hydraulic actuator that generates steering assisting force, a hydraulic control valve that is provided between the hydraulic pump and the hydraulic actuator to control the supply and discharge of hydraulic oil to and from the hydraulic actuator, and accommodates the hydraulic control valve. A valve housing having an inlet port forming portion in which an inlet port for hydraulic oil to the hydraulic control valve is formed;
A connecting member that is connected to a component for forming a hydraulic oil supply system from the discharge port forming part to the inlet port forming part so as to connect a conduit through which the hydraulic oil flows to the component. In a power steering apparatus having a valve body as a valve body, and a check valve for preventing a backflow of hydraulic oil from the hydraulic actuator to the hydraulic pump side, the check valve is an oil passage formed in the connecting member. A non-return valve having a valve body that is disposed inside thereof and at least a portion that comes into contact with the valve seat portion is formed of synthetic resin; and a compression coil spring that urges the valve body to seat on the valve seat portion. The valve has a first passage that allows hydraulic oil to flow between the inlet and the outlet of the check valve without passing through the compression coil spring in the radial direction. And A power steering system which is formed along the moving direction of the Kiben body.

As a result, in the power steering apparatus including the check valve for preventing the kickback phenomenon, the portion of the check valve that contacts the valve seat portion is made of synthetic resin.
When the check valve is closed, the collision noise generated when the valve body collides with the valve seat portion is reduced as compared with the case where the contacting portion is made of metal. Further, when the check valve opens, the hydraulic oil flowing in from the inlet of the check valve is deflected radially outward by the valve body, and then is not greatly deflected in the flow direction without being largely deflected by the compression coil spring. It flows into a first passage formed radially outward, and its main flow reaches the outlet portion through the first passage without passing through the compressed compression coil spring in the radial direction.

As a result, according to the invention of claim 1,
The following effects are exhibited. That is, in the power steering apparatus including the check valve for preventing the occurrence of the kickback phenomenon, when the check valve is closed, the collision sound generated when the valve body collides with the valve seat portion is reduced, Noise caused by the collision noise is reduced. Further, the check valve has a first passage that allows hydraulic oil to flow between the inlet portion and the outlet portion without passing through the compression coil spring in the radial direction, and is outside the compression coil spring in the radial direction, and has a valve body. By being formed along the moving direction of the check valve, when the check valve opens, the hydraulic oil flowing from the inlet of the check valve flows into the first passage without causing a large deflection in the flow direction. The main flow of the hydraulic oil reaches the outlet through the first passage without passing through the compression coil spring in the radial direction. Since it reaches the outlet through the first passage without passing through the compression coil spring in the radial direction, the pressure loss of hydraulic oil due to the compression coil spring of the check valve can be reduced as much as possible, and the response of the hydraulic actuator is improved. Therefore, the degree of freedom in designing the power steering apparatus is increased.

According to a second aspect of the present invention, in the power steering apparatus according to the first aspect, one end of the compression coil spring is held by the valve body and the other end thereof is the outlet of the connecting member. It is held by a spring receiver fixed to the connecting member by caulking the end portion forming the portion.

Thus, the spring receiver of the compression coil spring is fixed to the connecting member, which is the valve body, by caulking the end portion forming the outlet of the check valve. As a result, according to the invention described in claim 2, the following effect is exhibited in addition to the effect of the invention described in claim 1. That is, since the spring receiver of the compression coil spring is fixed to the end portion forming the outlet of the connecting member by caulking the end portion, the spring receiver can be easily assembled to the connecting member. The assembling property of the check valve in which the spring receiver is fixed to the connecting member (valve body) is improved.

According to a third aspect of the present invention, in the power steering apparatus according to the first or second aspect, a plurality of guide pieces contacting the wall surface of the oil passage are provided on the outer peripheral surface of the valve body. Formed to project in the radial direction at intervals in the direction,
The passage is formed by the guide pieces that are adjacent to each other in the circumferential direction between the wall surface and the valve body.

As a result, when the valve body moves, a plurality of guide pieces formed on the valve body slide on the wall surface,
Since the valve body is guided, the movement of the valve body in the connecting member becomes smooth, and the guide passages are used to form the first passage for suppressing the pressure loss of the hydraulic oil.

As a result, according to the invention of claim 3,
In addition to the effects of the invention described in the cited claims, the following effects are exhibited. That is, when the check valve is opened and closed, the valve body is guided by the plurality of guide pieces that are in sliding contact with the wall surface, so that the movement of the valve body in the connecting member is smooth and the guide pieces are used. Since the first passage is formed as a result, the first passage can be formed with a simple structure.

According to a fourth aspect of the present invention, in the power steering apparatus according to the second aspect, a second passage is formed in the spring receiver at a position overlapping with the first passage when viewed in the axial direction. A holding portion for holding the other end of the compression coil spring is formed near the center of the spring receiver with respect to the two passages.

Thus, the compression coil spring is held by the spring receiver fixed to the connecting member, and the main flow of the hydraulic oil flowing through the first passage passes through the second passage without passing through the compression coil spring in the radial direction. To reach the exit.

As a result, according to the invention of claim 4,
In addition to the effect of the invention described in claim 2, the following effect is exhibited. That is, the compression coil spring can be held by the spring receiver fixed to the connecting member, and the main flow of the hydraulic fluid flowing through the first passage passes through the second passage without passing through the compression coil spring in the radial direction. Since it reaches the outlet, the pressure loss due to the hydraulic oil passing through the compression coil spring in the radial direction can be reduced as much as possible even in the check valve in which the spring receiver is fixed to the connecting member.

In this specification, "axial direction", "radial direction" and "circumferential direction" mean "axial direction", "radial direction" and "circumferential direction" with reference to the compression coil spring.
Mean respectively.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 to 6 show a first embodiment of the present invention. Referring to FIGS. 1 and 2, a power steering apparatus 1 to which the present invention is applied is a rack and pinion type hydraulic power steering apparatus mounted on a vehicle. The power steering apparatus 1 includes a reservoir 2 that stores hydraulic oil.
From the hydraulic pump 3, the gear box 10, the suction pipe 4 provided between the reservoir 2 and the hydraulic pump 3, and the conduit provided between the hydraulic pump 3 and the gear box 10 through which the hydraulic oil flows. And a reflux pipe 6 provided between the gear box 10 and the reservoir 2.

The hydraulic pump 3 driven by the internal combustion engine mounted on the vehicle has a discharge port forming portion in which a discharge port is formed for hydraulic oil that has been sucked from the reservoir 2 through the suction pipe 4 and has a high pressure. It is supplied to a power cylinder mechanism 16 which will be described later and which is provided in the gear box 10 through a supply pipe 5 connected to 3a. The reservoir 2 has a power cylinder mechanism.
The hydraulic oil discharged from 16 flows in through the reflux pipe 6.

As shown in FIG. 1, the gear box 10 has a cylindrical housing 12 for accommodating a rack shaft 11 movably in its axial direction (in this embodiment, also in the lateral direction of the vehicle). And a valve housing 14 that is integrally formed near the end of the housing 12 and that houses the hydraulic control valve 13. One end of a pair of tie rods 15 is respectively connected to both ends of the rack shaft 11 via a pair of ball joints, and the other ends of both tie rods 15 are turned into steering wheels via an interlocking mechanism (not shown). Be connected.

A power cylinder mechanism 16 as a hydraulic actuator is provided in the middle of the housing 12. The power cylinder mechanism 16 includes a power cylinder 17 formed of a part of the housing 12, and a power piston 18 fixed to the rack shaft 11 and slidably fitted in the power cylinder 17 in the axial direction of the rack shaft 11. , A pair of first and second oil chambers 19 and 20 which are formed on both sides of the power piston 18, respectively.

The valve housing 14 has an input shaft 21 connected to a steering wheel (not shown) and an output shaft (rotatably connected via a torsion bar 22 integrally connected to the input shaft 21). And (not shown) are rotatably housed. A pinion that meshes with rack teeth formed on the rack shaft 11 is formed in the housing 12 at the lower end of the output shaft.

As shown in FIG. 2, the hydraulic control valve 13, which is a rotary valve, has a valve shaft 23 that rotates integrally with the input shaft 21.
And a valve sleeve 24 that accommodates the valve shaft 23 and rotates integrally with the output shaft. The valve shaft 23 having a plurality of lands 23a and the valve sleeve 24 having a control groove 24a are rotated relative to each other. Supply and discharge of hydraulic oil to and from the second oil chambers 19 and 20 are controlled. The valve housing 14 is connected to the supply pipe 5 and the inlet port into which the hydraulic oil from the hydraulic pump 3 flows.
Inlet port forming portion 14a in which 25 is formed, connecting portions 14b and 14c to which first and second oil pipes 7 and 8 respectively communicating with the first and second oil chambers 19 and 20 are respectively connected, and a return pipe 6 And a connecting portion 14d to which is connected.

When the steering wheel is operated, the rack shaft 11 is moved in the axial direction by the pinion that meshes with the rack teeth, and the left and right steered wheels are steered via the pair of tie rods 15. Done. At this time, the input shaft generated based on the reaction force from the road surface due to road surface resistance etc.
The hydraulic control valve 13 operates in accordance with the twist amount of the torsion bar 22 due to the rotation difference between the output shaft 21 and the output shaft, that is, the steering torque, and the hydraulic oil from the hydraulic pump 3 changes in accordance with the operating direction of the steering wheel. First oil chamber 19 (or second oil chamber
20) is supplied through the supply pipe 5 and the oil pipes 7 and 8, while the hydraulic oil in the second oil chamber 20 (or the first oil chamber 19) is discharged to the reservoir 2 through the return pipe 6 and the steering torque is changed. The hydraulic pressure is the first and second oil chambers 19 and 20 of the power cylinder mechanism 16.
The steering assist force generated based on the differential pressure between the oil chambers 19 and 20 is added to the rack shaft 11, and the steering force of the driver is reduced.

Therefore, the supply port 5 between the discharge port forming portion 3a, the inlet port forming portion 14a, and both port forming portions 3a, 14a supplies the hydraulic oil discharged from the hydraulic pump 3 to the power cylinder mechanism 16. Is a constituent element that constitutes a hydraulic oil supply system.

By the way, referring to FIG. 3, the hydraulic control valve
The flare sheet 26 is inserted into the inlet port 25 of the inlet port forming portion 14a of the valve housing 14 that accommodates 13, and the flared sheet 26 is further screwed into the flare sheet 26 and the inlet port forming portion 14a. The flare sheet 26 is sandwiched between the nuts 27, so that the flare sheet 26 becomes
The supply pipe 5 is connected to the flare sheet 26 while being connected to a. Therefore, the flare seat 26 is
The inlet port forming portion 14a of 14 constitutes a connecting member for connecting the supply pipe 5.

A supply pipe 5 is provided in the inlet port forming portion 14a.
With the flare seat 26 having an oil passage 28 communicating with the valve body as the valve body, the valve is opened when the hydraulic oil discharged from the hydraulic pump 3 and flowing into the inlet port 25 through the supply pipe 5 has a hydraulic pressure exceeding a predetermined hydraulic pressure. Then, the hydraulic oil is allowed to be supplied to the first and second oil chambers 19 and 20 of the power cylinder mechanism 16 via the hydraulic control valve 13, and the above-mentioned kickback phenomenon is prevented in order to prevent the above-mentioned vehicle. A check valve 30 that prevents the hydraulic oil in the first oil chamber 19 or the second oil chamber 20 from flowing back to the hydraulic pump 3 side by an external force applied to the steered wheels when the vehicle runs on a curb is built in.

The check valve 30 has a valve body 31 made entirely of synthetic resin, and a valve seat portion in which the valve body 31 is formed on a flare seat 26.
Compression coil spring 3 for seating on 26a and closing the valve
2 and a compression coil spring 32 whose one end 32a is held by the valve body 31.
The spring body 33 holds the other end 32b of the valve body 31, the compression coil spring 32, and the spring bearing 33.
The flare sheet 26 is incorporated in the flare sheet 26 while being arranged side by side in the axial direction of the axis L1.

When the check valve 30 is opened / closed, the valve body 31 moving in the direction parallel to the axial direction is brought into contact with or separated from the valve seat portion 26a, so that the oil passage 28 is located upstream of the valve seat portion 26a. The valve body that is housed in the oil passage 28 by contacting the control portion 31a that opens and closes the inlet portion 28a (which is also the inlet portion of the check valve 30) formed by the portion of the check valve 30 and the wall surface 26b of the oil passage 28. A guide portion that slidably guides 31 to the flare sheet 26 along the oil passage 28, and a cylindrical groove 34 centered on the axis of the valve body 31 that is coaxial or parallel to the axis L1 of the compression coil spring 32 are provided. Forming cylindrical side 31
b and a cylindrical central protrusion 31c and a bottom 31d,
A compression coil spring 32 that is inserted into the groove 34 and comes into contact with the bottom portion 31d.
And a holding portion 35 that holds the one end portion 32a.

Referring also to FIGS. 4 and 6, the guide portion projects radially outward at equal intervals in the circumferential direction on the outer circumferential surface 31e of the side portion 31b which is also the outer circumferential surface of the valve body 31. In addition, it has three or more, in this embodiment, five plate-shaped guide pieces 31f extending in the axial direction. Each guide piece 31f has a side portion 31b.
Is extended longer than the downstream end 31b1 in the axial direction, and the front end face 31f1 in the axial direction is located on the same plane as the front end face 31c1 of the central protrusion 31c. Outer surface 31f of each guide piece 31f
2 guides the valve element 31 such that the valve element 31 surely moves in parallel to the axial direction by making surface contact with the wall surface 26b of the oil passage 28.

Then, between the outer peripheral surface 31e of the valve body 31 having the guide piece 31f and the wall surface 26b, and between the guide pieces 31f adjacent in the circumferential direction, when the check valve 30 is opened, the inlet port is opened. The passage 36 through which the hydraulic oil flows from the portion 28a to the outlet portion 28b (which is also the outlet portion of the check valve 30) formed by the portion of the oil passage 28 on the downstream side of the spring receiver 33 is the valve body 31. It is formed so as to extend to the end surface of the downstream end portion 31b1 of the valve body 31 along the moving direction. Therefore, these passages 36 are located radially outward of the compression coil spring 32.

The disk-shaped spring receiver 33 is arranged near the end face of the end portion forming the outlet portion 28b of the flare sheet 26, and has a thin annular projection 31g formed at the end portion of the flare sheet 26.
The flare sheet 26 is formed at the caulking portion 38 formed by caulking the entire circumference (indicated by a chain double-dashed line in FIG. 3).
Fixed to. The spring receiver 33, as shown in FIG.
A ring-shaped outer ring part that is crimped to the flare sheet 26.
33a and the compression coil spring 32 located at the center of the spring receiver 33.
Of the holding portion 33b with which the other end portion 32b abuts, and a plurality of radially extending portions that connect the outer ring portion 33a and the holding portion 33b and that extend in the radial direction. And a passage 37 formed of three arc-shaped long holes in this embodiment.

The holding portion 33b has a hemispherical protruding portion 33b1 protruding in the axial direction in the inner space of the compression coil spring 32,
The other end 32b of the compression coil spring 32 is surrounded by the protrusion 33b1.
By engaging with, the movement of the compression coil spring 32 in the radial direction is blocked. Further, the protruding portion 33b1 faces the central protruding portion 31c in the axial direction, and when the check valve 30 is opened, the tip end surface 31c1 of the central protruding portion 31c abuts the protruding portion 33b1 so that the valve body 31 Functioning as a stopper that defines the maximum value of the movement amount of the valve body 31, the valve body 31 occupies the maximum valve opening position at this time.

Further, the passage 36 is, as shown in FIG.
When viewed in the axial direction, the passage 36 is formed so as to have a portion that overlaps with the passage 37. Therefore, when the check valve 30 is opened, the passage 36 has a main flow that occupies most of the working oil flowing from the inlet portion 28a.
The passage does not pass through the compression coil spring 32 in the radial direction.
It is allowed to flow through 36 in the axial direction to reach the outlet 28b. Further, at the maximum open position of the check valve 30, the side portion 31
A gap in the axial direction is formed between the downstream end 31b1 of b and the spring receiver 33. Then, this gap can be adjusted to an optimum value by changing the protrusion amount of the protrusion 33b1 that defines the maximum valve opening position by plastically deforming the protrusion 33b1.

Next, the operation and effect of the embodiment configured as described above will be described. When the steering wheel is operated, the hydraulic fluid discharged from the hydraulic pump 3 passes through the check valve 30 that opens due to the hydraulic pressure, and further operates according to the steering wheel operating direction and steering torque. While being supplied to the first oil chamber 19 (or the second oil chamber 20) via 13, the hydraulic oil of the second oil chamber 20 (or the first oil chamber 19) is passed through the hydraulic pressure control valve 13 and the return pipe 6 The steering assist force is applied to the rack shaft 11 by passing through it to the reservoir 2.

When the vehicle rides on a curb, the external force applied to the steered wheels is transmitted to the rack shaft 11, and the piston moves the hydraulic oil in the first oil chamber 19 or the second oil chamber 20 to the hydraulic pump 3 side. When a reverse flow is to be made, the check valve 30 prevents the reverse flow and prevents the kickback phenomenon from occurring.

Since the valve body 31 of the check valve 30 is made of synthetic resin including the control portion 31a, the valve body 31 collides with the valve seat portion 26a when the check valve 30 is closed. The collision sound generated by this is reduced as compared with the case where the portion of the valve body 31 in contact with the valve seat portion 26a is metal, the noise caused by the collision sound is reduced, and the valve body 31 is lightweight. Therefore, the open / close response of the check valve 30 is improved.

On the outer peripheral surface 31e of the valve body 31, there is provided a passage 36 which allows hydraulic oil to flow between the inlet portion 28a and the outlet portion 28b of the check valve 30 in the radially outward direction of the compression coil spring 32. And extending along the moving direction (axial direction) of the valve body 31 to the downstream end portion 31b1 of the valve body 31, when the check valve 30 opens, the check valve 30 passes through the supply pipe 5 and reverses. The hydraulic fluid that has flowed in from the inlet portion 28a of the stop valve 30 flows radially outward along the control portion 31a, and then flows into the passage 36 without significant deflection of the flow direction, and the main flow of hydraulic fluid is , Compression coil spring 32
Since it reaches the outlet 28b of the check valve 30 through the passage 36 without passing through in the radial direction, the pressure loss of the hydraulic oil due to the compression coil spring 32 of the check valve 30 can be reduced as much as possible, and The responsiveness of the cylinder mechanism 16 can be improved, and the degree of freedom in designing the power steering apparatus 1 is increased.

When the check valve 30 is opened and closed, the valve body 31 is
A plurality of guide pieces 31f formed on the outer peripheral surface 31e of the wall surface 26b
The sliding contact with the valve body 31 guides the valve body 31 so as to move in the axial direction along the wall surface 26b.
The movement of the valve body 31 inside becomes smooth. Since the passage 36 is formed by using the guide pieces 31f, the passage 36 can be formed with a simple structure.

Since the spring bearing 33 of the compression coil spring 32 is fixed to the flare sheet 26 which is the valve body by the caulking portion 38 at the end portion forming the outlet portion 28b, the spring bearing 33 is attached to the flare sheet 26. This facilitates the assembly of the check valve 30 in which the spring receiver 33 is fixed to the flare seat 26 which is the valve body.

The spring bearing 33 is provided with a passage when viewed in the axial direction.
A passage 37 is formed at a position overlapping with the passage 36, and a holding portion 33b for holding the other end 32b of the compression coil spring 32 is formed near the center of the spring receiver 33 with respect to the passage 37, thereby fixing the flare sheet 26 to the flare sheet 26. Compressed coil spring by spring receiver 33
In addition to holding 32, the main flow of hydraulic oil flowing through the passage 36 reaches the outlet 28b through the passage 37 without passing through the compression coil spring 32 in the radial direction. Even in the check valve 30 fixed to, the pressure loss due to the hydraulic oil passing through the compression coil spring 32 in the radial direction can be reduced as much as possible.

Further, the other end 32b of the compression coil spring 32 is
Is held by the holding portion 33b so as to be prevented from moving in the radial direction, so that the one end portion 32a is held by the holding portion 35 forming the groove 34, and the buckling of the compression coil spring 32 is prevented. And the inclination can be effectively prevented.

The maximum opening position of the check valve 30 can be easily adjusted by changing the amount of protrusion of the protrusion 31b1 which also functions as the holding portion 33b of the spring receiver 33 by plastic deformation.

Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. The second embodiment is different from the first embodiment mainly in the structure of the valve body of the check valve, and is basically the same in other respects. Therefore, the explanation of the same parts is omitted or simplified,
The different points will be mainly described. The same reference numerals are used for the same or corresponding members as those of the first embodiment.

In the second embodiment, the pipe joint 41, which is a 90 ° elbow pipe joint that constitutes the valve body of the check valve 40, includes a connecting portion 41a into which the flare seat 26 is inserted, and a valve housing 14.
Of the inlet port forming portion 14a and a flange portion 41e, and the inlet port forming portion is inserted into the insertion hole 44 formed in the flange portion 41e as shown in FIG. It is connected to the valve housing 14 by a pair of bolts (not shown) screwed into screw holes formed in 14a.

The oil passage 42 formed in the pipe joint 41 has a connecting portion 41.
The first oil passage 42a mainly formed in a and the second oil passage 42b mainly formed in the fitting portion 41b and orthogonal to the first oil passage 42a are formed, and the supply pipe 5 is the same as in the first embodiment. Further, the tip end thereof is sandwiched between the flare sheet 26 and the flare nut 27 screwed into the connecting portion 41a, so that the flare sheet 26 is connected to the pipe joint 41. Therefore, the pipe joint 41 is a connecting member.

Then, in the pipe joint 41, the fitting portion 41b
In addition, the valve body 31, the compression coil spring 32, and the spring receiver 33 of the first embodiment have the valve body 31, the compression coil spring 32, and the spring receiver 33 that have the same shape except for their sizes.

The inlet portion 42c of the check valve 40 is composed of the first oil passage 42a and the portion of the second oil passage 42b upstream of the valve seat portion 41c formed in the pipe joint 41. The outlet portion 42d of the check valve 40 is formed of a portion of the second oil passage 42b on the downstream side of the spring receiver 33.

The valve element 31 is urged by the compression coil spring 32 so as to be seated on the valve seat portion 41c, and the guide piece 31f is connected to the oil passage 42.
Of the wall surfaces 41d, the wall surface 41d1 of the second oil passage 42b in which the valve body 31 is housed is brought into surface contact, and the valve body 31 is guided so that the valve body 31 surely moves in parallel to the axial direction. Also, the spring receiver 33
Is a caulking portion that is formed by caulking a protrusion 41g (shown by a chain double-dashed line in FIG. 7) formed in the same manner as in the first embodiment on the end surface of the end portion where the outlet portion 42d of the oil passage 42 is formed. 43 by pipe fitting 41
Fixed to.

According to this second embodiment, the flare sheet 26
By replacing the pipe joint 41 with the pipe joint 41, the same action and effect as those of the first embodiment can be obtained, and the following action and effect can be obtained. That is, since the pipe joint 41 connected to the valve housing 14 also constitutes the check valve 40, by using the pipe joint 41 larger than the flare seat 26, the valve body 31 and the compression coil spring 32 can be easily assembled. As a result, the ease of assembly of the power steering apparatus 1 having the check valve 40 for preventing the kickback phenomenon is improved.

Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the second embodiment mainly in the connection structure of the supply pipe 5, and is basically the same in other respects. Therefore, the description of the same parts will be omitted or simplified, and different points will be mainly described. The same reference numerals are used for the same members as the members of the second embodiment or the corresponding members.

In the third embodiment, the supply pipe 5 is a pipe joint.
It is fixed by being welded to the connecting portion 41a of 41 by the welding portion 43. According to the third embodiment, the same action and effect as those of the second embodiment are obtained, and since the flare nut 27 is not used, the number of parts is reduced.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is different from the first embodiment mainly in the structure of the valve body of the check valve and in that there is no spring bearing fixed to the valve body, and the rest has basically the same configuration. is there. Therefore, the description of the same parts will be omitted or simplified, and different points will be mainly described. The same reference numerals are used for the same or corresponding members as those of the first embodiment.

A pipe joint 51 forming the valve body of the check valve 50.
Is connected to the inlet port forming portion 14a of the valve housing 14 by a bolt (not shown) as in the second embodiment.
As in the first embodiment, the supply pipe 5 is connected to the pipe joint 51 by being sandwiched between the flare sheet 26 and the flare nut 27 screwed into the pipe joint 51, and the flare sheet 26 is further inserted. The oil passage 52a and the second oil passage 52a orthogonal to the first oil passage 52a.
An oil passage 52 including the oil passage 52b is formed. Therefore, the pipe joint 51 is a connecting member.

The pipe joint 51 has a valve body 31 of the check valve 50.
And a compression coil spring 32 are incorporated. Here, the valve body 31
Is urged by the compression coil spring 32 so as to be seated on the valve seat portion 26a formed on the flare sheet 26.

The other end 32b of the compression coil spring 32 is connected to the pipe joint 5
In the wall surface 51a of the first oil passage 52, in order to form an annular groove 53 in the wall surface 51a1 that faces the valve body 31 in the axial direction, a central portion 51b surrounded by the groove 53 and a radially outer portion of the groove 53 are formed. It is held by a holding portion 54 composed of a peripheral portion 51c and a bottom portion 51d. That is, the other end 32b of the compression coil spring 32 inserted into the groove 53
Are held in contact with the bottom portion 51d. Then, in order to assemble the check valve 50, the compression coil spring 32 is held by the holding portion 35 of the valve body 31, the valve body 31 integrated with the compression coil spring 32 is assembled to the pipe joint 51, and then the check valve is assembled. The flare sheet 26 is press-fitted so that the spring force of the compression coil spring 32 when the valve 50 is in the closed state generates a fixing force that does not move the flare sheet 26.

Further, the guide piece 31f comes into surface contact with the wall surface 51a2 of the first oil passage 52a in which the valve body 31 is housed, so that the valve body 31 is securely moved in parallel with the axial direction. invite. Further, in the valve body 31, the tip surface 31c1 of the central protruding portion 31c has the central portion 5c.
1b occupies the maximum valve opening position, and at this maximum valve opening position, the axial gap between the tip surface 31b1 of the side portion 31b and the wall surface 51a1 on which the holding portion 54 is formed causes a pressure loss. When the check valve 50 is opened, the working oil that has been formed so as to be as small as possible flows through the gap from the inlet portion 52c, which is constituted by a portion of the oil passage 52 on the upstream side of the valve seat portion 26a,
It reaches the outlet formed by the second oil passage 52b and further flows into the inlet port 25 of the valve housing 14.

According to the fourth embodiment, except for matters relating to the spring receiver 33, the same operations and effects as those of the first embodiment are exhibited, and the following operations and effects are exhibited. That is, the pipe joint 51 connected to the valve housing 14 is connected to the check valve 50.
Since it also configures, the pipe fitting 51 larger than the flare sheet 26
By using the valve body 31 and the compression coil spring 32.
Of the power steering apparatus 1 having the check valve 50 for preventing the kickback phenomenon is improved. Further, since the spring receiver 33 is not used, the number of parts is reduced.

In the following, an example in which a part of the configuration of the above-described example is modified will be described with respect to the modified configuration.
In each of the above-mentioned embodiments, the valve body 31 was formed entirely of synthetic resin, but at least the control portion 31a,
A valve body in which the portion that contacts the valve seat is made of synthetic resin
May be 31. Further, the passage 36 is formed on the outer peripheral surface 31e of the valve body 31.
However, it is also possible to form the outer peripheral surface of the valve body 31 by a cylindrical surface and form a groove for forming a passage on the wall surface of the oil passage that is in surface contact with the outer peripheral surface.

The valve body constituting the check valve is the flare sheet 26 or the pipe joints 41, 51 which is connected to the inlet port forming portion 14a as a component in each of the above embodiments.
Flare sheet 26 or pipe joint 41, 51 which is a connecting member
In addition to the valve housing 14, for example, a plurality of discharge pipe forming portions 3a of the hydraulic pump 3 and a plurality of supply pipes 5 that make hydraulic oil flow between the hydraulic pump 3 and the hydraulic control valve 13 of the valve housing 14 are provided. It may be a component that constitutes the supply system of hydraulic oil, including a pipe joint that interconnects conduits.

[Brief description of drawings]

FIG. 1 is an overall schematic view of a power steering apparatus including a check valve according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram centering on an oil passage of the power steering apparatus of FIG.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is a side view of a valve body of the check valve of FIG.

5 is a view of the spring receiver of the check valve as viewed from the direction of arrow A in FIG. 3. FIG.

6 is a VI of FIG. 3 of a flare nut that is part of the check valve.
FIG. 6 is a cross-sectional view taken along line VI-VI and is a view of the valve body and the spring receiver viewed from the arrow A.

FIG. 7 shows a second embodiment of the present invention, and FIG.
It is a figure equivalent to.

FIG. 8 is a view on arrow B of FIG. 7.

FIG. 9 shows a third embodiment of the present invention, and FIG.
It is a figure equivalent to.

FIG. 10 shows a fourth embodiment of the present invention and is a view corresponding to FIG. 3 of the first embodiment.

[Explanation of symbols]

1 ... Power steering device, 2 ... Reservoir, 3 ... Hydraulic pump, 3a
... Discharge port forming part, 4 ... Suction pipe, 5 ... Supply pipe, 6 ... Reflux pipe, 7, 8 ... Oil pipe, 10 ... Gear box, 11 ... Rack shaft, 12 ... Housing, 13 ... Hydraulic control valve, 14 ... Valve Housing, 14a ... Inlet port forming part, 15 ... Tie rod, 16 ... Power cylinder mechanism, 17 ... Power cylinder, 18 ... Power piston, 19, 20 ... Oil chamber, 21 ... Input shaft, 22 ... Torsion bar, 23 ... Valve shaft , 24 ... Valve sleeve, 25 ... Inlet port, 26 ...
Flare sheet, 26a ... Valve seat, 27 ... Flare nut, 28 ...
Oil passage, 28a ... Inlet portion, 28b ... Outlet portion, 30 ... Check valve, 31 ... Valve body, 31e ... Outer peripheral surface, 31f ... Guide piece, 32 ... Compression coil spring,
33 ... Spring receiver, 33b ... Holding part, 34 ... Groove, 35 ... Holding part, 3
6, 37 ... passage, 38 ... caulking portion, 40 ... check valve, 41 ... pipe joint, 42 ... oil passage, 42c ... inlet portion, 42d ... outlet portion, 43 ... welded portion, 44 ... insertion hole, 50 ... reverse Stop valve, 51 ... Pipe joint, 52 ... Oil passage,
52c ... inlet part, 52d ... outlet part, 53 ... groove, 54 ... holding part, L1 ...
Axis.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3D033 EB01 EB05 EB07                 3H058 AA02 BB35 CA06 CA14 CA22                       CB06 CB11 CD05 CD26 EE03                       EE18

Claims (4)

[Claims] 1. A hydraulic pump having a discharge port forming portion in which a discharge port for discharging hydraulic oil is formed, a hydraulic actuator operated by hydraulic pressure of the hydraulic oil to generate a steering assist force, the hydraulic pump and the hydraulic pump. A hydraulic control valve that is provided between the hydraulic actuator and controls the supply and discharge of hydraulic oil to and from the hydraulic actuator, and an inlet that accommodates the hydraulic control valve and that forms an inlet port for the hydraulic oil to the hydraulic control valve. In order to connect a valve housing having a port forming portion and a conduit through which the operating oil flows to the components from the discharge port forming portion to the inlet port forming portion that constitute a hydraulic oil supply system to the hydraulic actuator, A non-return valve that prevents the backflow of hydraulic fluid from the hydraulic actuator to the hydraulic pump by using the connecting member connected to the component as a valve body. In a power steering apparatus including a valve, the check valve is arranged in an oil passage formed in the connecting member, and at least a portion in contact with the valve seat portion is formed of synthetic resin, A compression coil spring for urging the valve body to be seated on the valve seat portion, and the check valve includes an inlet portion of the check valve without hydraulic oil passing through the compression coil spring in a radial direction. The power steering apparatus is characterized in that a first passage that allows flow between the outlet and the outlet is formed radially outward of the compression coil spring and along the moving direction of the valve body. 2. The compression coil spring has one end held by the valve body and the other end fixed to the connecting member by caulking the end forming the outlet of the connecting member. The power steering apparatus according to claim 1, wherein the power steering apparatus is held by a spring receiver. 3. A plurality of guide pieces, which come into contact with the wall surface of the oil passage, are formed on the outer peripheral surface of the valve body so as to radially protrude at intervals in the circumferential direction. The guide piece is formed between the wall surface and the valve body and is adjacent in the circumferential direction, and the guide piece is formed.
The power steering apparatus described. 4. A second passage is formed in the spring receiver at a position overlapping the first passage when viewed in the axial direction.
The power steering apparatus according to claim 2, wherein a holding portion for holding the other end portion of the compression coil spring is formed near the center of the spring receiver with respect to the passage.