JP2001324037A - Check valve with variable throttle and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To simplify the structure of an in-line type check valve with a variable throttle used for a steering damper for mitigating an impact such as kickback, reduce the number of assembly steps, and reduce the manufacturing cost. SOLUTION: An inner pipe 23 having a first reduced diameter portion 23a forming a valve seat of a check valve 21 for preventing a fluid from flowing in one direction, and forming a first flow path 24 therein, The valve has a second reduced diameter portion 25a that forms a valve seat of the variable throttle valve 22 that allows a flow in the valve closing direction when the check valve is closed. An outer pipe 25 forming a second flow path 26 therebetween is provided.
The variable throttle valve is disposed between a valve body 27 that closes a check valve by contacting a first reduced diameter portion and a second reduced diameter portion that is slidably held in a second flow path. Valve body 29 for closing the valve
And urging means 30 for urging the cylindrical valve body in the direction of the second reduced diameter portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve which is incorporated in a fluid pressure piping system of various fluid pressure utilizing devices and apparatuses to allow a fluid flow in one direction, and a check valve in a valve closing direction. The present invention relates to an in-line type check valve with a variable throttle and a method of manufacturing the check valve.

[0002]

2. Description of the Related Art A check valve with a variable throttle of this type operates a power cylinder to obtain a power assisting force (steering assisting force) by, for example, controlling switching of a flow path switching valve in accordance with a steering operation of a steering wheel. 2. Description of the Related Art In a power steering apparatus, a power steering apparatus is used as a damper valve of a steering damper used to attenuate an impact when a reverse input is made from a steered wheel side such as kickback.

The hydraulic power steering apparatus includes a flow path switching valve for selectively connecting a pump and a tank to left and right chambers of a power cylinder in accordance with a steering operation of a steering handle. The flow path switching valve supplies pressure oil to a power cylinder chamber corresponding to a steering operation to apply a power assist force for turning a steered wheel.

[0004] In an automobile equipped with a power steering device, a power steering device provided with the steering damper is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-219.
No. 70, Japanese Utility Model Application Laid-Open No. 61-176065, Japanese Patent Application Laid-Open No. 62-43367, and the like. These steering dampers are used when driving a car.
For example, a shock caused by a reverse input (so-called kickback; hereinafter simply referred to as a reverse input) acting from the steered wheels due to unevenness of the traveling road surface or an obstacle is attenuated and reduced, so that the shock is not transmitted to the steering wheel. It is for doing.

That is, this type of steering damper is provided in a left and right cylinder passage between a passage switching valve and a left and right chamber of a power cylinder in a power steering device.
When the above-described reverse input acts, a variable throttle valve is provided to provide resistance to the flow of the hydraulic oil discharged from the return chamber of the power cylinder with the movement of the piston, and in parallel with these variable throttle valves. Each check valve is provided, and by opening the check valve of the corresponding cylinder passage at the time of positive input by the steering operation, it is possible to sufficiently supply the pressure oil from the pump to the cylinder chamber via the flow path switching valve. It has a structure.

[0006]

However, the damper valve used in the above-mentioned conventional steering damper generally has a large valve body, and a check valve and a variable throttle valve are arranged in a passage formed in the valve body. The structure is installed in a state where it is installed, and the number of components is large, the structure is complicated, and the assembling work is troublesome, resulting in a problem of high cost.

Further, since the conventional damper valve uses a large-scale valve body as described above, it is generally provided integrally or integrally with a valve housing for a flow path switching valve of a power steering device. There is also a problem that the versatility is poor, and the increase in size and weight of the entire apparatus cannot be avoided.

For this reason, the number of parts constituting the above-mentioned steering damper can be reduced, the structure can be simplified, and the assembling operation can be simplified. In addition, measures to reduce the size, weight, and cost of the entire apparatus can be achieved. It is also desired to take it.

The present invention has been made in view of such circumstances, and has been developed to provide an in-line type non-return check valve having a check valve and a variable throttle valve to a standard pipe material having different diameters. An object of the present invention is to provide a check valve with a variable throttle and a method of manufacturing the check valve, which can be formed in combination to simplify the structure, reduce the overall weight, reduce the number of assembly steps, and reduce the manufacturing cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a check valve with a variable throttle used as a damper valve for alleviating an impact at the time of reverse input from a steered wheel side, such as kickback in a power steering apparatus, and a method of manufacturing the same. .

[0011]

In order to meet such an object, a check valve with a variable throttle according to the present invention (the invention according to claim 1) has a check valve for preventing a fluid from flowing in one direction. A check valve with a variable throttle, comprising a valve and a variable throttle valve that allows a flow in the valve closing direction when the check valve is closed.
An inner pipe having a first reduced diameter portion forming a valve seat of the check valve and forming a first flow path therein; and a second reduced diameter portion forming a valve seat of the variable throttle valve. An outer pipe fitted outside the inner pipe and forming a second flow path between the outer pipe and the inner pipe; and a valve for closing the check valve by contacting the first reduced diameter portion. The body and the second
A cylindrical valve body slidably held in the flow path of the second valve and closing the variable throttle valve with the second reduced-diameter portion, and moving the cylindrical valve body in the direction of the second reduced-diameter portion. And a biasing means for biasing the pressure.

The check valve with a variable throttle according to the present invention (the invention according to claim 2) is the check valve with a variable throttle according to claim 1, wherein the inner pipe is provided with a first enlarged diameter portion. The end of the urging means is locked to the first enlarged diameter portion.

According to the present invention (the first or second aspect of the present invention), an inner pipe and an outer pipe are prepared, each of which is provided with a reduced diameter portion and an increased diameter portion, and the inner pipe is provided with a check valve. The valve body, the cylindrical valve body of the variable throttle valve, and the urging means are appropriately assembled, and an outer pipe is fitted thereto,
By joining at least one end in the longitudinal direction, a check valve with a variable throttle can be formed.

A check valve with a variable throttle according to the present invention (the third aspect of the present invention) includes a check valve for preventing fluid from flowing in one direction, and a check valve for closing the check valve when the check valve is closed. A check valve with a variable throttle, comprising a variable throttle valve allowing flow, a first reduced diameter portion forming a valve seat of the check valve, and a first radial expansion forming a valve seat of the variable throttle valve. And an inner pipe having a first flow path therein, an outer pipe fitted outside of the inner pipe and forming a second flow path between the inner pipe and the first pipe, The variable throttle valve is disposed between the valve body that closes the check valve by contacting the reduced diameter portion and the first enlarged diameter portion that is slidably held in the second flow path. It is characterized by comprising a cylindrical valve body for closing the valve, and urging means for urging the cylindrical valve body in the direction of the first enlarged diameter portion. To.

The check valve with variable throttle according to the present invention (the invention according to claim 4) is the check valve with variable throttle according to claim 3, wherein the outer pipe is provided with a second reduced diameter portion. The end of the biasing means is locked to the reduced diameter portion of (2).

According to the present invention (the third or fourth aspect of the present invention), similarly to the first and second aspects of the present invention, the inner pipe and the outer pipe are prepared, and the diameter of each of the inner pipe and the outer pipe is reduced. Part, the enlarged diameter part, the valve body of the check valve, the cylindrical valve body of the variable throttle valve, the biasing means are appropriately assembled to the inner pipe, the outer pipe is fitted to these, and at least one end in the longitudinal direction. By joining them, a check valve with a variable throttle can be formed.

A check valve with a variable throttle according to the present invention (invention of claim 5) has a check valve for preventing a fluid from flowing in one direction, and a check valve for closing the check valve when the check valve is closed. A method for manufacturing a check valve with a variable throttle, comprising a variable throttle valve allowing a flow, wherein a second flow path is formed between an inner pipe having a first flow path formed therein and the inner pipe. A step of expanding or reducing the diameter at an appropriate position with the outer pipe to be formed, and incorporating a valve element constituting the check valve into the inner pipe, and forming the variable throttle valve on the outer peripheral side of the inner pipe. Assembling the valve body and biasing means;
Fitting the outer pipe to the outside of the inner pipe,
A step of radially overlapping and joining the inner pipe and the outer pipe at at least one end in the longitudinal direction, and a step of connecting each end of the outer pipe to a pipe on the connected side. And

According to the present invention (the invention described in claim 5),
It is possible to assemble by preparing two pipe materials with different diameters, an inner pipe and an outer pipe, reducing and expanding the diameter of these, and incorporating the valve body of each valve, etc.
Connection with the connected pipe is also possible.

[0019]

1 to 3 show one embodiment of a check valve with a variable throttle and a method of manufacturing the same according to the present invention. In these figures, in this embodiment,
As shown in FIG. 3, the non-return valve with variable throttle 11 according to the present invention is used in left and right damper units 10A and 10B constituting a steering damper 10 in a hydraulic power steering apparatus 1 using pressure oil as a pressure fluid. A description will be given of a case where the present invention is applied.

FIG. 3 shows an outline of a hydraulic circuit in a power steering apparatus indicated by reference numeral 1 as a whole. This hydraulic circuit supplies pressure oil supplied from a pump P, which is a hydraulic source, through a supply passage 2 to a hydraulic circuit. Left and right chambers CL, C of a power cylinder (indicated by P / C) as a device actuator via a flow path switching valve (control valve) CV that is switched and controlled by a steering operation (not shown) by a steering handle.
It is configured to feed to R and return to tank T.

In the figure, 3 and 4 are the left of the power cylinder P / C,
Left and right cylinder passages 5 and 5 to the right chamber are return passages from the flow path switching valve CV to the tank T. In this embodiment, a rotary flow path switching valve C including a rotor and a sleeve is used.
V is used.

In the power steering device 1,
The passage switching valve CV is used to control the steering operation state of the steering wheel (for example, the steering direction, the steering angle, the steering speed, etc.) and the passages 3, 4 to the left and right chambers CL, CR of the power cylinder P / C.
Is controlled by switching. By this switching, the pressure oil from the pump P is supplied to one of the chambers CL and CR, and the other chamber is connected to the tank T, so that the power cylinder P /
By C, a power assist force for assisting the steering force is obtained. As this is widely known,
Detailed description here is omitted.

In the power steering device 1,
In the middle of the left and right cylinder passages 3, 4, a pair of left and right variable throttle valves 6, 7 constituting the steering damper 10 are provided, respectively. These variable throttle valves 6 and 7 are supplied from one of the chambers CL and CR of the power cylinder P / C to the tank T via the flow path switching valve CV at the time of reverse input from the steered wheel side such as kickback or the like. It is configured such that the opening area changes depending on the passing flow rate on the return side.

The variable throttle valves 6 and 7 are provided with a flow path resistance caused by passing a flow on the return side from the return side chamber CL or CR of the power cylinder P / C caused by an impact at the time of reverse input from the steered wheels. Attenuates, relaxes, and functions as a damper. Further, the variable throttle valves 6 and 7 allow the flow on the return side from the cylinder chamber to the flow path switching valve CV, and depend on the passing flow rate. When the flow rate from the cylinder chamber is large, the throttle opening is large. The smaller the flow rate, the smaller the aperture of the throttle.

The left and right cylinder passages 3 and 4 of the power steering device 1 are provided with respective chambers C of the power cylinder P / C.
A steering damper 1 that blocks a return flow from L and CR to the tank T via the flow path switching valve CV.
0, a pair of left and right check valves 8 and 9 are connected in parallel to the respective variable throttle valves 6 and 7, and these valves form a pair of left and right damper units 10A and 10B. ing.

The non-return valves 8 and 9 are closed so as to prevent the flow on the return side when the above-mentioned reverse input from the steered wheels is performed. The variable throttle valves 6 and 7 are provided with check valves 8 and
9 is provided so as to allow the flow in the valve closing direction with a predetermined fluid resistance.

According to the present invention, the above-described variable throttle valve 6,
7, right and left damper portions 10A,
The check valve with a variable throttle 11 serving as a damper valve in 10B is characterized in that it is configured as shown in FIGS. Hereinafter, the structure and the manufacturing method will be described in detail.

As shown in FIG. 1, the check valve 11 with a variable throttle has a first reduced diameter portion 23a forming a valve seat of the check valve 21 (8, 9). An inner pipe 23 forming a flow path 24; and the variable throttle valve 22 (6, 7).
An outer pipe 25 having a second reduced-diameter portion 25a forming the valve seat and being fitted to the outside of the inner pipe 23 and forming a second flow path 26 between the inner pipe 23 and the inner pipe 23. . The first and second reduced diameter portions 23a, 23
5a is formed by beading or the like.

In the inner pipe 23, a ball 27 as a valve body for closing the check valve 21 by abutting on the first reduced diameter portion 23a is incorporated. In FIG. 1, reference numeral 28 denotes a ball stopper pin for preventing the ball 27 from dropping, and is provided at a position where the opening and closing operation of the ball 27 can be permitted so as to pass through the inner pipe 23. The ball stopper pin 27 penetrates a hole formed in the inner pipe 23 in the radial direction, and is locked by bending both ends. However, such a ball stopper pin 27 may be provided by press fitting or the like, or may be simply inserted. This is because the escape is restricted by the outer pipe 25, and at this time, the length may be appropriately set.

On the outer peripheral portion of the inner pipe 23, a cylinder which is slidably held in the second flow path 26 and closes the variable throttle valve 22 with the second reduced diameter portion 25a. And the cylindrical valve body 29 is connected to the second reduced diameter portion 25a.
A compression coil spring 30 is provided as urging means for urging in the direction. In the figure, reference numeral 31 denotes a spring receiving ring for locking the other end of the compression coil spring 30.
1 is locked by a first enlarged diameter portion 23b formed in the inner pipe 23 by beading or the like so that movement in the longitudinal direction is restricted. This first enlarged diameter portion 2
3b, the other end of the compression coil spring 30 may be directly locked.

In this embodiment, the cylindrical valve element 29
Similarly to the inner pipe 23 and the outer pipe 25 described above, the inner pipe 23 is formed by a tubular member 29a made of a pipe material and a flange 29b bent at one end in the longitudinal direction thereof. Of course, the cylindrical valve body 29 may be formed from a cylindrical material.

Here, in the cylindrical valve body 29 formed of such a pipe material, there is a clearance between the inner wall and the inner pipe 23 so that the fluid leaks. However, such a clearance does not cause any problem when the check valve 21 is in the open state. Also, when the check valve 21 is closed and the flow rate of the pressure oil is small, it functions to ensure the minimum opening of the variable throttle valve 22. In this way, for example, the return of the steering wheel is improved. Notches or small holes may be provided in the flange 29b to secure such a minimum opening.

In the drawing, reference numerals 33a and 33b denote passage holes formed in the inner pipe 23 so as to communicate with the second flow path 26 bypassing the check valve 21. 34a, 34 in the figure
“b” is a narrowed portion whose diameter is reduced so that both ends of the outer pipe 25 in the longitudinal direction are overlapped with both ends of the inner pipe 23, and these narrowed portions 34a, 34
b is formed, for example, by swaging.

Here, the check valve 11 with a variable throttle having the above-described configuration is constructed such that an 8 mmφ pipe material is used as the inner pipe 23, a 15 mmφ pipe material is used as the outer pipe 25, and a 10 mmφ pipe material is used as the cylindrical valve body 29. It is formed by using. These pipe materials are pipe materials used as standard products in metal pipes for automobile piping, and can be easily and inexpensively obtained. Therefore, most of the check valve 11 with a variable throttle can be formed only by using such pipe materials and performing a process of appropriately reducing and expanding the diameter of these pipe materials. In addition, the above-mentioned dimensions are as follows.
It is an example when it is formed of a pipe material.

The check valve 11 with a variable throttle having the above-described configuration.
Can be easily assembled as follows. That is, an inner pipe 23 and an outer pipe 25, which are generally used standard pipe materials and have different diameters, are prepared, and each of the inner pipe 23 and the outer pipe 25 is expanded and reduced in diameter by beading as shown in FIG. Apply processing. And
A ball 27 constituting the check valve 21 is incorporated in the inner pipe 23, and a cylindrical valve body 29, a compression coil spring 30, and a spring receiving ring constituting the variable throttle valve 22 are provided on the outer peripheral side of the inner pipe 23. 31 and finally the ball stopper pin 28. The ball stopper pin 28 also serves to prevent the cylindrical valve body 29, the compression coil spring 30, and the spring receiving ring 31 from dropping off.

Thereafter, the outer pipe 25 is concentrically fitted on the outer side of the inner pipe 23, and at least one end in the longitudinal direction of the inner pipe 23 and the outer pipe 25 (the left end in the central view of FIG. 2). ) And overlap in the radial direction. This joint may be joined by brazing or the like, but may be integrally joined by brazing (brazing portion 13b) at the time of joining with the connected pipe 13 connected to this end. Further, at the end on one end side, the end of the outer pipe 25 and the connection-side pipe 13 may be joined at a position spaced apart outward in the longitudinal direction.

The check valve with variable throttle 11 obtained by assembling as described above is of a so-called in-line type, in which a first flow path 24 is formed in an inner pipe 23, and an inner pipe 23 and an outer pipe 23 are formed. 25, a second flow path 26 is formed. In this state, one end of each of the pipes 23 and 25 is connected to the connection side pipe 1.
3 and the other end is preferably connected to the connected pipe 12. Here, at the end of the check valve 21 in the valve closing direction, the squeezed portion 34b of the outer pipe 25 is overlapped with the end of the inner pipe 23 and brazed (the brazed portion 12).
The case shown in FIG. However, the present invention is not limited to this, and only the end of the outer pipe 25 is connected to the connection-side pipe 1 independently of the inner pipe 23.
2 or may be joined at a position separated from the joint with the inner pipe 23 in the longitudinal direction outside.

In the figure, reference numerals 12a and 13a denote connected side pipes 12,
13 is an enlarged diameter portion provided at the connection end. If such enlarged diameter portions 12a and 13a are provided, the check valve with variable throttle 1
Positioning workability at the time of joining to the first pipes 12 and 13 can be improved. In addition, such enlarged diameter portions 12a,
The reduced diameter portions 23a, 25a and the increased diameter portion 23b of the inner pipe 23 and the outer pipe 25, including the inner pipe 13a, may be formed by, for example, beading using a roll, a bulge, a rolling machine, or the like. If the processing method using the core metal is used, the processing accuracy can be ensured.
These are effective when used as the valve seats of the check valve 21 and the variable throttle valve 22. In addition, the outer pipe 25
The squeezed portions 34a and 34b for connecting the pipes can be formed by, for example, swaging.

The check valve 11 with the variable throttle according to the above configuration.
Are 6.35 mmφ, 8 mmφ, 10 m from among standard products generally known as metal pipes for automobile piping, for example.
Most of them can be formed only by using pipe materials of mφ and 15 mmφ and subjecting them to appropriate processing such as diameter reduction and diameter expansion.

The in-line type check valve with variable throttle 11 thus obtained can be incorporated into a part of a pipe connecting the valve CV and the cylinders CL and CR, so that a conventional valve body is provided. It has a greater degree of freedom in arrangement as compared with the type that uses the same, and can be used as a damper valve for a steering damper of a power steering device.

FIG. 4 shows a second embodiment of the present invention.
In this embodiment, the ball 2 constituting the check valve 21
A compression coil spring 41 for urging the ball 7 is used in place of the ball stopper pin 28, and a preload is applied so that the behavior of the ball 27 can be suppressed. With this configuration, resistance can be given when the pressure oil flows in,
There is an advantage that a feeling of response can be given to the steering wheel when traveling straight ahead. Although the other end of the spring 41 is shown as being locked at the end of the connected pipe 13, the present invention is not limited to this.

FIGS. 5A and 5B show a third embodiment of the present invention and a modification thereof. In this embodiment,
In the cylindrical valve body 29 constituting the variable throttle valve 22, the flange 29 b is formed inward, and is slidably held on the inner peripheral portion of the outer pipe 25, and a second enlarged diameter portion formed on the inner pipe 23. An example using 42 as a valve seat is shown. In FIG. 5A, reference numeral 43 denotes a second reduced diameter portion formed on the outer pipe 25, which is used as a spring locking portion of the spring 30. FIG. 5B shows an example in which the second reduced diameter portion 43 is omitted and a reduced diameter portion reaching the narrowed portion 34 b of the outer pipe 25 is used as a spring locking portion of the spring 30.

The present invention is not limited to the structure described in the above embodiment, and it goes without saying that the shape, structure, etc. of each part can be appropriately modified or changed. For example, in the above-described embodiment, the ball 2 is used as the valve body of the check valve 21.
Although the example using 7 has been described, the present invention is not limited to this, and a valve plug having an appropriate shape can be freely used.

Although the case where the compression coil spring 30 is used as the urging means of the variable throttle valve 22 has been described as an example, the present invention is not limited to this, and a disc spring or the like capable of urging the cylindrical valve body 29 can be used. Any suitable urging means may be used. Further, as the cylindrical valve body 29 constituting the variable throttle valve 22, for example, a case in which a cylindrical member 29a and a flange 29b provided at the end thereof are formed from a pipe material has been described. The present invention is not limited to this, and may have any equivalent structure. Also, the inner pipe 23 and the outer pipe 2
5 may be formed from other than a standard pipe material.

Further, the check valve 1 with a variable throttle according to the present invention.
1 is not limited to the damper valve for the steering damper 10 of the power steering apparatus 1 described in the above-described embodiment, but also functions as a check valve in various fluid pressure piping systems and controls the flow in the valve closing direction. The present invention can be used for various fluid pressure utilizing devices and devices such as a shock absorber which requires a juxtaposition of a variable throttle valve that allows under a predetermined fluid pressure condition.

[0046]

As described above, according to the check valve with a variable throttle and the method of manufacturing the same according to the present invention, the reduced diameter portion and the increased diameter portion are formed at appropriate locations made of pipe materials having different diameters. Inner pipe and outer pipe, check valve body,
Since it is formed by the cylindrical valve element of the variable throttle valve and the urging means, the structure is simplified, the assembling work is simple, the overall weight can be reduced, and the cost can be reduced.

In particular, the check valve with a variable throttle according to the present invention is almost entirely formed of a standard pipe material in a metal pipe for an automobile pipe, and furthermore, a processing such as a diameter reduction and a diameter expansion is appropriately performed. In addition to simplifying the structure described above, reducing the overall weight, simplifying the assembly work,
Significant cost reduction can be achieved.

Also, the check valve with a variable throttle according to the present invention can be easily incorporated in the middle of the fluid pressure pipe as an in-line type, so that no installation space is required and there is a degree of freedom in installation. There are advantages. Furthermore, such a check valve with a variable throttle only needs to be incorporated in the middle of a conventional fluid pressure pipe, so that there is an advantage that it can be easily adopted in existing fluid pressure utilizing equipment.

According to the present invention, the reduced diameter portion and the increased diameter portion of the inner pipe and the outer pipe can be formed very easily by, for example, beading with a roll, a bulge, a rolling machine, or the like. Since the accuracy can be ensured, it is effective in using these as a check valve or a valve seat of a variable throttle valve. In particular, when a cored bar is used, the shape and dimensional accuracy of the reduced diameter portion and the increased diameter portion can be further improved. In addition, the squeezed portion for connecting the inner pipe and the connected pipe of the outer pipe can be easily formed by, for example, swaging.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing one embodiment of a check valve with a variable throttle according to the present invention.

FIG. 2 is a view for explaining a method of manufacturing the check valve with a variable throttle shown in FIG. 1;

FIG. 3 is a schematic diagram for explaining a hydraulic circuit of a power steering device provided with a steering damper to which the check valve with a variable throttle according to the present invention is applied.

FIG. 4 is a cross-sectional view of a main part showing a modification of the check valve with variable throttle of FIG. 1;

FIGS. 5 (a) and 5 (b) are cross-sectional views of relevant parts showing another modified example of the check valve with variable throttle shown in FIGS. 1 and 4. FIG.

[Explanation of symbols]

1. Power steering device, 2. Supply passage, 3, 4 ...
Left and right cylinder passages, 3a, 4a: passage switching valve, cylinder passage portion between variable throttle valves, 5: return passage, 6, 7 ... variable throttle valve, 8, 9 ... pilot operated check valve, 8a, 9
a: pilot pressure passage, 10: steering damper, 1
0A, 10B: left and right damper portions, 11: check valve with a variable throttle used as a damper valve, 12, 13: connected pipe, 12a, 13a: enlarged diameter portion, 12b, 13b: joined portion by brazing, 21 ... check valve, 22 ... variable throttle valve, 23 ... inner pipe, 23a ... first reduced diameter portion, 23
b: first enlarged diameter part, 24: first flow path, 25: outer pipe, 25a: second reduced diameter part, 26: second flow path, 27
... ball (valve element), 28 ... ball stopper pin, 29 ... cylindrical valve element, 29a ... cylindrical part, 29b ... flange, 30 ... compression coil spring (biasing means), 31 ... spring receiving ring, 33
a, 33b: passage hole, 34a, 34b: squeezed portion, 41
… Compression coil spring, 42… diameter enlarged portion (first enlarged diameter portion), 4
3: reduced diameter portion (second reduced diameter portion), P: pump, T: tank, CV: flow path switching valve (control valve), P / C
... power cylinder, CL, CR ... left and right cylinder chambers.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16K 17/04 F16K 17/04 D 47/10 47/10 F16L 55/04 F16L 55/04 F term (Reference) 3D033 ED02 ED05 HA00 3H025 CA03 CB35 3H058 AA04 BB29 CB02 CC02 CD04 CD27 CD28 EE03 3H059 AA03 AA09 BB15 BB30 CA05 CB02 CC02 CC08 CD04 CF01 CF06 EE01 FF03 3H066 AA12 EA09 EA09 EA09

Claims (5)

[Claims] 1. A check valve with a variable throttle, comprising: a check valve for preventing a fluid from flowing in one direction; and a variable throttle valve for allowing a flow in a valve closing direction when the check valve is closed. An inner pipe having a first reduced diameter portion forming a valve seat of the check valve and forming a first flow path therein; and a second reduced diameter portion forming a valve seat of the variable throttle valve. An outer pipe fitted outside of the inner pipe and forming a second flow path between the outer pipe and the inner pipe; and a valve for closing the check valve by contacting the first reduced diameter portion. A cylindrical valve body that is slidably held in the second flow passage and closes the variable throttle valve between the second reduced diameter portion; And a biasing means for biasing in the direction of the reduced diameter portion. 2. The check valve with a variable throttle according to claim 1, wherein a first enlarged diameter portion is provided on the inner pipe, and an end of the urging means is locked to the first enlarged diameter portion. A check valve with a variable throttle. 3. A check valve with a variable throttle, comprising: a check valve for preventing a flow of a fluid in one direction; and a variable throttle valve for allowing a flow in a valve closing direction when the check valve is closed. An inner pipe having a first reduced diameter portion forming a valve seat of the check valve and a first enlarged diameter portion forming a valve seat of the variable throttle valve, and forming a first flow passage therein; An outer pipe fitted outside the inner pipe to form a second flow path between the inner pipe and the inner pipe; and a valve body closing the check valve by contacting the first reduced diameter portion. A cylindrical valve body slidably held in the second flow path and closing the variable throttle valve between the first enlarged diameter portion and the first valve body; And a biasing means for biasing in the direction of the enlarged diameter portion. 4. The check valve with a variable throttle according to claim 3, wherein a second reduced diameter portion is provided on the outer pipe, and an end of the urging means is locked to the second reduced diameter portion. Check valve with variable throttle. 5. A method for manufacturing a check valve with a variable throttle, comprising a check valve for preventing a fluid from flowing in one direction and a variable throttle valve for allowing a flow in the valve closing direction when the check valve is closed. A method of subjecting an inner pipe forming a first flow path inside and an outer pipe forming a second flow path between the inner pipe to a diameter increasing or reducing processing at an appropriate position. A step of assembling a valve element constituting the check valve in the inner pipe, and assembling a cylindrical valve element and biasing means constituting the variable throttle valve on the outer peripheral side of the inner pipe; Fitting the outer pipe to
A step of radially overlapping and connecting the inner pipe and the outer pipe at at least one end in the longitudinal direction, and a step of connecting each end of the outer pipe to a pipe on a connection side. Of manufacturing a check valve with a variable throttle.