JPH06300150A - Pipe coupling with valve, check valve, and check valve structure - Google Patents

Abstract

PURPOSE:To provide a coupling with a valve, a check valve, and a check valve structure which are constituted to reduce the size of a device having a hydraulic circuit and reduce the number of using parts by incorporating a valve mechanism of a line of which the hydraulic circuit consists. CONSTITUTION:A check valve comprises a seat surface formed in the line of a check valve housing 31; and a poppet 32 energized toward the seat surface through the force of a coil spring 33. On the outlet side of the check valve, a spring support 34 is securely screwed in the check valve housing 31 to support the coil spring 33. Male screw is formed on the outer peripheral surface of the check valve housing 31, the check valve is securely screwed in a pipe coupling and used in a state to be incorporated therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint with a valve, a check valve and a check valve structure, and more particularly to a technique for incorporating a valve mechanism in a pipe forming a fluid pressure circuit.

[0002]

2. Description of the Related Art In a hydraulic circuit of an apparatus, each pipe is connected by a pipe joint to facilitate the disassembly and assembly of the hydraulic circuit, and as shown in FIG.
When supplying hydraulic pressure to 0, etc., the check valve 11 is connected to the pipe 112 connected by the pipe joint 111.
3 and the throttle valve 114 are connected by flange coupling or gasket coupling to form a meter-in circuit or the like.

[0003]

Therefore, in the conventional piping method, in addition to the piping space,
Since a space for arranging pipe joints and pipes for the check valve 113 and the throttle valve 114 is also required, there is a limit to the space saving of the hydraulic circuit and there is a problem that the number of parts constituting the circuit is large. Moreover, a large number of throttle valves are used not only in the meter-in circuit but also in many hydraulic circuits, and as the number of throttle valves used increases, the number of pipe joints and pipes accordingly increases.

In view of the above problems, the object of the present invention is to
By incorporating a valve mechanism in the pipelines that make up hydraulic circuits, etc., we will realize pipe fittings with valves, check valves, and check valve structures that can reduce the size of devices equipped with hydraulic circuits and reduce the number of parts used. Especially.

[0005]

In order to solve the above-mentioned problems, according to the present invention, the inside of the pipe joint body is provided with a seat surface formed in the pipe line, a state in which the seat surface is in close contact with the seat surface, and a seat surface. It is characterized in that the valve-equipped pipe joint is configured by providing a valve body that can be displaced in the pipe line in a separated state and a biasing means that biases the valve body toward the seat surface.

Here, the urging means is composed of a spring for urging the valve body and a spring receiving member which is screwed and fixed to the pipe joint body and holds the spring in a compressed state in the pipe line. Preferably in this case,
After inserting the valve body and spring into the pipe joint body,
The valve-equipped pipe joint can be easily manufactured simply by screwing and fixing the spring receiving member into the pipe joint body.

In the present invention, it is preferable that a male thread is formed on the outer peripheral side surface of the pipe joint body so that the valve-equipped pipe joint is constructed as a screw-in type pipe joint. Further, the valve body may be formed with an orifice penetrating the valve body.

According to another aspect of the present invention, a seat surface formed in a cylindrical check valve housing and a valve body displaceable in the fluid passage in a state of being in close contact with the seat surface and a state of being separated from the seat surface. And a biasing means for biasing the valve body toward the seat surface, the check valve housing has an outer peripheral surface provided with a male screw capable of being screwed into a female screw in a conduit forming a fluid pressure circuit. It is characterized by being formed.

Here, the urging means is composed of a spring for urging the valve element and a spring receiving member which is screwed and fixed in the check valve housing to hold the spring in a compressed state in the check valve housing. It is preferable to configure.

Also in the check valve according to the present invention, the valve body may be provided with an orifice penetrating it. Further, an orifice penetrating the check valve housing may be formed on the side surface of the check valve housing at a position closer to the fluid outlet side of the check valve than the seat surface.

In still another form of the present invention, a seat surface formed in a conduit (a conduit formed inside various hydraulic components) forming a fluid pressure circuit and a state in which the seat surface is in close contact with the seat surface. And a valve element displaceable in the pipe line in a state of being separated from the seat surface, a spring for biasing the valve body toward the seat surface, and screwed and fixed in the pipe line,
The check valve mechanism is configured by a spring receiving member that holds the spring in a compressed state in the pipe line.

[0012]

In the valve-fitted pipe joint according to the present invention, since the valve body and its urging means for the seat surface are provided in the body of the pipe joint, the fluid flow in the same direction as the urging direction of the valve body. The flow is blocked while the fluid flow in the opposite direction is free. That is, since the pipe fitting itself has the function of a check valve, it is possible to reduce the number of parts that make up the hydraulic circuit and the like, and also to have a structure in which the valve is also arranged in the conventional piping space. The size can be reduced.

Further, in the check valve according to the present invention, a male screw is formed on the outer peripheral surface of the check valve housing, and the check valve is screwed into the conduit of the fluid pressure circuit by utilizing this male screw. Therefore, since the check valve can be built in the conduit of the fluid pressure circuit, it is possible to reduce the size of the device including the hydraulic circuit. Further, the direction in which the flow of the fluid is restricted can be easily switched by simply switching the screwing direction of the check valve to the opposite direction.

[0014]

EXAMPLE 1 FIG. 1 is a schematic cross-sectional view schematically showing the structure of a valve-equipped pipe joint according to an example of the present invention and its method of use.

In the drawing, a pipe fitting with valve 1 of this example is a screw-in type in which a pipe passage 3 is formed inside a straight pipe fitting body 2 and external threads 21 and 22 are formed on the outer peripheral surface thereof. It is a pipe joint.

A seat surface 4 as a stepped portion having a curved surface is formed at an intermediate position of the pipe passage 3 of the pipe joint body 2, and the inner diameter of the base end side of the pipe joint body 2 is larger than the seat surface 4. A contact surface 51 that can be in close contact with the seat surface 4 is provided on the pipe line 3.
A poppet 5 is disposed as a valve body having a front end of the poppet. The contact surface 51 of the poppet 5 is the seat surface 4
The inside of the conduit 3 can be moved so as to be in close contact with the seat surface 4 and to be separated from the seat surface 4. A protrusion 52 for receiving a spring is formed on the side surface of the poppet 5, while an internal thread 31 is formed on the open end side of the conduit 3, and a disc-shaped spring receiver 6 is screwed therein. ing. Here, the spring receiver 6 has a fluid passage hole 61.
Are formed. Further, a coil spring 7 (biasing means) that biases the poppet 5 toward the seat surface 4 is arranged between the spring receiver 6 and the projection 52 of the poppet 5. Therefore, in the inside of the pipe line 3, in a state where the seat surface 4, the poppet 5 and the coil spring 7 constitute a check valve, one of the both ends of the pipe joint body 2 is located on the biasing direction side of the coil spring 7. The end is the inlet 11, and the opposite end is the outlet 12.

Further, in the pipe joint with valve 1 of this example, an orifice 9 having a large inner diameter on the proximal side of the poppet 5 and a small inner diameter on the distal side thereof is provided inside the poppet 5 along the axial direction thereof. Has been formed.

The valve-equipped pipe joint 1 having such a configuration is connected to the pipe 13 constituting the hydraulic circuit of the apparatus by the union nut 14 via the male threads 21 and 22 on the outer peripheral side surface.
It functions not only as a pipe joint but also as a valve directly connected to the pipe 13. That is, in a state where the pipe 13 is directly connected to both the inlet 11 and the outlet 12 of the valve-equipped pipe joint 1, the fluid supplied from the direction indicated by the arrow A causes the fluid pressure of the fluid to reach the urging force of the coil spring 7 and poppet. Push 5 towards exit 12. As a result, the contact surface 51 of the poppet 5 and the seat surface 4 are separated from each other, and a fluid passage is secured around the seat surface 4 from the inlet 11 side toward the outlet 12. ,
The fluid flow in this direction is free. On the contrary,
The fluid supplied from the direction indicated by the arrow B acts on the contact surface 51 of the poppet 5 in close contact with the seat surface 4 together with the urging force of the coil spring 7 due to the fluid pressure, so that the outlet 12 is provided around the seat surface 4. From the side of entrance 1
The fluid passage toward the 1 side is blocked. Therefore, the valve-equipped pipe joint 1 functions as a check valve that regulates the fluid supply direction.

Further, the poppet 5 of the valve-equipped pipe joint 1 of the present example.
Since the orifice 9 is formed in the valve, it functions as a throttle valve for the fluid in the direction of arrow B. Therefore, by using it as shown in FIG. 2, an ideal meter-in circuit can be constructed. That is, when supplying the hydraulic oil to the working chambers 103 and 104 of the actuator 10, female threads 105 and 106 are formed in the cylinder 101, and the valve-equipped pipe joint 1 of this example is fitted therein with the male threads 2 on the outer peripheral surface.
1, which does not require a large occupied space or a long piping distance, unlike the hydraulic circuit using the conventional pipe joint and valve shown in FIG.

As described above, in the pipe fitting with valve 1 of this example, the valve fitting itself is a pipe joint and has a valve function. The same function as when a joint and a valve are provided is exhibited. Therefore, when configuring the hydraulic circuit in the device, the valve can be provided in a small piping space, so that the device can be downsized. Moreover, since the number of parts used can be reduced, the device can be constructed at low cost. Further, since the inside of the fluid passage is simplified by reducing the number of parts constituting the hydraulic circuit, it is possible to suppress the generation of noise accompanying the flow of fluid. Furthermore, since the internal configuration of the valve-equipped pipe joint 1 is simple, the occurrence of failures is small.

Since the valve (pipe joint with valve 1) can be directly connected to the actuator 10, the distance from the working chambers 103 and 104 of the actuator 10 to the pipe joint with valve 1 (check valve and throttle valve) is substantially. Since it becomes zero, the space can be saved and the number of parts can be reduced, and the influence from the fluid path between them can be eliminated, so that the flow rate adjustment and the like can be easily and accurately performed.

Further, in the pipe fitting with valve 1 of this example,
Since the valve body is formed of the poppet 5 having the orifice 9, the passage of fluid is free in one direction (direction of arrow A) and the other direction (direction of arrow B).
For, a fixed throttle can be used for the passage of fluid. Therefore, since the configuration of the hydraulic circuit can be simplified, the meter-in circuit of the actuator 10 can be configured without using the manifold block. Moreover, the mounting direction of the valve-equipped pipe joint 1 to the actuator 10 is shown in FIG.
The meter-in circuit can be easily changed to the meter-out circuit simply by changing the state shown in (1) to the opposite direction.
Further, the aperture amount can be set to an arbitrary value depending on the diameter of the orifice 9.

Modification of Embodiment 1 In the pipe fitting with valve 1 of this embodiment, the poppet 5 is adopted as the valve body and the orifice 9 is formed in the poppet 5 to provide the throttle valve function. May be formed as a check valve in which the passage of the fluid is free in one direction while the passage of the fluid is completely blocked in the other direction. .

When the check valve is used, a spherical body can be used as the valve body.

Furthermore, the shape of the valve-equipped pipe joint 1 is not limited to that of this example, and as shown in FIG. 3 (a), the pipe joint body 2 has an L-shape, and its pipe line is straight. Seat surface 4, poppet 5 (valve body), coil spring 9 on parts etc.
And a spring receiver 6 (biasing means) arranged,
As shown in FIG. 3 (b), a male thread 23 is continuously formed on the outer peripheral side surface of the pipe joint body 2, and as shown in FIG. 3 (c), different diameters are provided at both ends of the pipe joint body 2. 3D, which has connecting portions 20 on three or four sides of the pipe joint body 2 and has a seat surface and a valve body in any one of the pipe lines. Further, it is possible to configure a device provided with a biasing means.

In the case of the valve-equipped pipe joint 1 having the shape shown in FIG. 3 (b) among these shapes, as shown in FIG. 4 (a), a pipe 27a connected by utilizing its male screw 23,
It is also possible to use the valve-equipped pipe joint 1 completely housed inside 28a. In addition, as shown in FIG.
It is also possible to directly connect the pipe 28a and the pipe 27b in a state where the pipe fitting with valve 1 itself is simply stored as a check valve assembly inside a hydraulic component such as the pipe 27b.

Second Embodiment Next, a check valve according to a second embodiment will be described with reference to FIGS. 5 and 6.

FIG. 5 is a sectional view showing the structure of the check valve of this embodiment, and FIG. 6 is an exploded perspective view showing the structure of each member constituting the check valve.

In these figures, the check valve 3 of this example is
0 is the conduit 310 of the cylindrical check valve housing 31.
A valve mechanism is formed inside, and a small opening on one side of the valve mechanism serves as a fluid inlet 311 and an open end on the other side serves as a fluid outlet 316.

In this example, a female screw 313 is formed on the inner peripheral surface of the check valve housing 31 on the outlet 316 side, while the seat surface 31 is formed on the inlet 311 side.
2 is formed.

Further, a male screw 317 is formed on the outer peripheral surface of the check valve housing 31, and as will be described later, the male screw 317 is utilized to make the check valve 30
It is used in the state that it is built in the pipeline that constitutes the hydraulic circuit. Here, the male screw 317 is formed in a region that is biased toward the outlet 316 side, and the inlet 311 side and the outlet 316 side can be visually recognized due to the width of the region where the screw is not formed.

Inside the conduit 310, there is a poppet 32 (valve body) inserted from the outlet 316 side, and this poppet 32 is displaceable in the conduit 310 along its axial direction. Is in a state. The poppet 32 has a conical surface on the tip side, and the conical surface is the contact surface 321 for the seat surface 312.
Is. The interior of the poppet 32 is hollow, and four fluid passage holes 324 penetrating the poppet 32 are formed in the conical surface of the poppet 32 toward the central axis. Here, the formation positions of the fluid passage holes 324 are both on the fluid outlet 316 side with respect to the contact portion between the poppet 32 and the seat surface 312.

In addition, the coil spring 33 is provided in the conduit 310.
This coil spring 33 has its tip end side in contact with the step portion 323 inside the poppet 32, while its base end side is supported by the spring receiver 34 and is in a compressed state. Are urged toward the seat surface 312. The spring receiver 34 has a base 34.
2 and the protrusion 343, and the fluid passage hole 340 penetrates them. Of these, a male screw 341 is formed on the outer periphery of the protruding portion 343, and the spring receiver 34 is screwed and fixed to the check valve housing 31 by utilizing the male screw 341 and the female screw 313 of the check valve housing 31.

The check valve 30 having such a structure is assembled as follows.

First, the conduit 3 of the check valve housing 31
Inside the 10, the poppet 32 is inserted from the outlet 316 side, and then the coil spring 33 is inserted.

Next, at the side of the outlet 316, the male screw 3
41 and the female screw 313, the spring receiver 3
4 is screwed and fixed to the check valve housing 31, and the coil spring 33 is put into a compressed state. As a result, the coil spring 3
3 is in a state in which the poppet 32 is biased to the seat surface 312.

Check valve 30 assembled in this way
In the above, the biasing force of the coil spring 33 with respect to the poppet 32 is adjusted by the screwing amount of the spring receiver 34 with respect to the check valve housing 31.

In the check valve 30 of this embodiment, as shown in FIG. 6, a groove 3 is formed on the tip surface of the check valve housing 31.
On the other hand, as shown in FIG. 7, a groove 345 is also formed on the end surface of the spring receiver 34. Therefore, the spring receiver 34 is attached to the check valve housing 3
The operation of screwing into 1 can be performed by inserting a flat-blade screwdriver shaft into each of these grooves 315 and 345.

As shown in FIG. 8, the check valve 30 thus constructed is used in a state where it is built in a pipe joint or a pipe. That is, the male screw 41 is formed on the outer peripheral side of the pipe portion 40a of the pipe joint 40, while the female screw 42 is formed on the inner peripheral side thereof, and the female screw 42 and the female screw 313 of the check valve 30 (check valve housing 31) are connected to each other. Utilizing this, the check valve 30 is built in the pipe portion 40a. In this state, the pipe 44 having the female screw 43 is connected to the pipe portion 40a of the pipe joint 40.

In this state, the fluid supplied from the direction indicated by the arrow C pushes the poppet 32 toward the outlet 316 side by the urging force of the coil spring 33 due to the fluid pressure, so that the fluid flowing in from the inlet 311 is removed. Since it passes through the inside of the poppet 32 through the fluid passage hole 324, the fluid flow in this direction is free. On the other hand, the fluid supplied from the direction indicated by the arrow D causes the fluid pressure to bring the contact surface 321 of the poppet 32 into close contact with the seat surface 312 due to the urging force of the coil spring 33, so that the fluid passage is blocked.

As described above, in the check valve 30 of this example, the male screw 3 is attached to the outer peripheral surface of the check valve housing 31.
17 is formed, and using this male screw 317,
The check valve 30 is screwed into the conduit of the fluid pressure circuit, for example inside the fitting 40. Therefore, the check valve 30
Is completely contained in the pipeline of the hydraulic circuit, so that the piping space of the hydraulic circuit can be reduced. In addition, the direction in which the flow of the fluid is restricted can be easily switched to the opposite direction only by reversing the screwing direction of the check valve 30.

In the check valve 30, the poppet 32 and the coil spring 33 are inserted into the conduit 310 of the check valve housing 31 from the outlet 316 side, and then the spring receiver 34 is screwed and fixed to the check valve housing 31. You can assemble just by doing. Therefore, the manufacturing cost of the check valve 30 is low. Further, even when the conditions of the hydraulic circuit are adjusted or changed, the poppet 32 is replaced with one having a different diameter of the fluid passage hole 324, the coil spring 33 is replaced with one having a different biasing force, or the spring receiver 34 is screwed in. The performance of the check valve 30 can be easily changed only by changing the amount.

Modified Example of Embodiment 2 In the check valve 30 according to Embodiment 2, as shown by the broken line in FIG. 9, an orifice 328 is formed in the poppet 32 so as to penetrate the poppet 32 in the axial direction, Arrow E
Fixed throttling may be performed on the fluid in the direction.

Further, instead of the orifice 328, in the poppet 32, the fluid passage hole 324 formed on the side of the outlet 316 with respect to the contact portion with the seat surface 312 is used, while the side surface of the check valve housing 31 is used. Of these, the orifice 319 may be formed at a position closer to the outlet 316 than the seat surface 312 to secure the fluid passage indicated by the arrow F, and the fixed restriction may be performed on the fluid in the direction of the arrow E. In this case, it has been confirmed that the noise caused by the flow of the fluid is reduced as compared with the case where the orifice 328 is used.

Third Embodiment FIG. 10 is a sectional view showing a check valve mechanism according to the third embodiment.

In this figure, the check valve mechanism 6 of this example is shown.
No. 0 uses the piping itself and the hydraulic components themselves that form the hydraulic path as the check valve housing 62, and the seat surface 64 is formed in the piping 63, and the poppet 65 and the coil spring 66 are inserted. ing. A female screw 69 is formed on the side of the outlet 61 of the conduit 63, and a spring receiver 68 having a male screw 67 is screwed and fixed by using this female screw 69. The seat surface 64 formed in the pipe passage 63 can use, for example, a stepped portion formed in the pipe or a stepped portion formed at a joint between different pipes.

In the check valve mechanism 60 having such a structure, if the seat surface 64 and the female screw 69 are formed in the pipe 63, the poppet 65, the coil spring 6 and the spring receiver are used without using a separate check valve. The check valve mechanism 60 can be configured only by using 68, and the flow of fluid can be regulated.

In any of the embodiments, the fluid used in the fluid circuit is not limited to hydraulic oil, and may be water or air, and the type thereof is not limited.

[0049]

As described above, in the valve-equipped pipe joint according to the present invention, since the seat surface and the valve body are provided in the pipe, the valve joint function is provided in addition to the function as the pipe joint. Have. Therefore, according to the present invention, since the function of both the pipe joint and the valve is exhibited by one valve joint, the space occupied by the hydraulic circuit or the like can be reduced, and the device provided therewith can be downsized, and the number of parts can be reduced. It can be reduced.

Further, in the pipe fitting with valve according to the present invention,
When an orifice is formed in the valve element, the passage of fluid in one direction is free, and fixed throttling can be performed on the fluid in the opposite direction. The amount can be set arbitrarily. Further, the meter-in circuit or the like can be easily configured by directly connecting to the actuator or the like. In this case, the actuator and the pipe joint with the valve are connected to each other at the shortest distance, so that the influence of the fluid passage on the flow rate can be eliminated.

The check valve according to the present invention is characterized in that a male thread is formed on the outer peripheral surface of the check valve housing. Therefore, according to the present invention, the check valve can be built in the pipe joint, the pipe, or the like by simply screwing and fixing the check valve by using the internal thread inside the pipe joint, so that the piping space can be reduced.

In the check valve mechanism according to the present invention,
The present invention is characterized in that a seat surface and a female screw are formed in a pipe forming a fluid pressure circuit, a valve body and a spring are inserted therein, and then a spring receiver is screwed and fixed. Therefore, according to the present invention, the conduit itself forming the fluid pressure circuit is used for the housing of the check valve,
A check valve mechanism can be built in it. Therefore, it is not necessary to use a single check valve, and the piping space can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic sectional view schematically showing a pipe joint with valve and a method of using the pipe joint according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory view schematically showing a state in which the pipe joint with valve shown in FIG. 1 is connected to an actuator.

3 (a) to 3 (d) are explanatory views schematically showing the shape of a pipe joint with a valve according to a modification of the embodiment of the present invention.

FIG. 4 is an explanatory view schematically showing how to use the pipe joint with valve shown in FIG. 3 (b).

FIG. 5 is a schematic cross-sectional view schematically showing the configuration of the check valve according to the second embodiment of the present invention.

FIG. 6 is an exploded view showing a part of the components of the check valve shown in FIG.

7 is a rear view of a spring receiver of the components of the check valve shown in FIGS. 5 and 6. FIG.

FIG. 8 is an explanatory view schematically showing how to use the check valve shown in FIG.

FIG. 9 is a schematic cross-sectional view schematically showing the configuration and usage of a check valve according to an improved example of the second embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view schematically showing the configuration of the check valve mechanism according to the third embodiment of the present invention.

FIG. 11 is an explanatory diagram schematically showing a configuration of a conventional meter-in circuit.

[Explanation of symbols]

1 ... Pipe fitting with valve 2 ... Pipe fitting main body 3, 310, 63 ... Pipe line 4, 64, 312 ... Seat surface 5, 32, 65 ... Poppet (valve body) 6, 34, 68 ... Spring receiver 7, 33, 66 ... Coil spring 9, 319, 328 ... Orifice 10 ... Actuator 11, 311 ... Inlet 12, 61, 316 ... Outlet 21, 22 , 23, 41, 67, 317, 341 ...
Male screw 30 ... Check valve 31, 62 ... Check valve housing 40 ... Pipe fitting 42, 43, 69, 313 ... Female screw 60 ... Check valve mechanism 324 ... Fluid passage hole

Claims (9)

[Claims] 1. A seat surface formed in the pipe passage inside the pipe joint body, and a valve body displaceable in the pipe passage in a state of being in close contact with the seat face and in a state of being separated from the seat surface. And a biasing device that biases the valve body toward the seat surface. 2. The spring according to claim 1, wherein the urging means is screwed and fixed to a spring for urging the valve body toward the seat surface and the pipe joint body, and the spring is connected to the pipe line. A pipe fitting with a valve, comprising: a spring receiving member that holds the compressed state inside. 3. The valve-equipped pipe joint according to claim 1, wherein the pipe joint body is a screw-in type pipe joint having an external thread formed on an outer peripheral surface thereof. 4. The valve-equipped pipe joint according to claim 1, wherein the valve body has an orifice formed therethrough. 5. A seat surface formed in a tubular check valve housing, a valve body displaceable in the fluid passage in a state of being in close contact with the seat surface and in a state of being separated from the seat surface, and the valve. An urging means for urging the body toward the seat surface, and a male screw capable of being screwed into a female screw in a conduit forming a fluid pressure circuit is formed on an outer peripheral surface of the check valve housing. Check valve characterized by that. 6. The check mechanism according to claim 5, wherein the biasing means is a spring for biasing the valve body toward the seat surface, and is screwed and fixed in the check valve housing to check the spring. A check valve, comprising: a spring receiving member that holds the compressed state in the valve housing. 7. The check valve according to claim 5, wherein the valve body has an orifice formed therethrough. 8. The check valve according to claim 5, wherein an orifice penetrating the side surface of the check valve housing is formed at a position closer to a fluid outlet than the seat surface. 9. A seat surface formed in a conduit forming a fluid pressure circuit, a valve body displaceable in the conduit so as to be in close contact with the seat surface and apart from the seat surface, A check valve structure comprising: a spring for urging the valve body toward the seat surface; and a spring receiving member that is screwed and fixed in the pipe line to hold the spring in a compressed state. .