KR20050040704A - 4 circuit protection valve - Google Patents

Abstract

Providing a four-circuit protection valve which can reduce the number of parts, and can maintain strong strength by having a valve body as a unitary structure.

The four-circuit protection valve 1 has a valve body 3, the valve body 3 extends in the first axial direction 5 and the second axial direction 7, respectively; A check valve opening for forming the first check valve portion 51 and the second check valve portion 53, which is formed as a single body that is bent as a whole in the curved portion 13 to form the second body portion 11; 54 is formed at an accessible position from the outer walls 87 and 88 of the bent portion 13 without passing through other members.

Description

4 CIRCUIT PROTECTION VALVE

The present invention relates to a four-circuit protection valve for a vehicle.

Japanese Patent Laid-Open No. 2000-264193 discloses a conventional four-circuit protection valve for a vehicle. In order to increase the reliability of the air system, a four-circuit protection valve may be used in a vehicle in which service brakes, parking brakes, clutches, suspensions, or other auxiliary devices are operated by air pressure.

This four-circuit protection valve is a 1st output port C1 via the 1st piston valve B1 and the 2nd piston valve B2 to the primary chamber A1 to which air is supplied from an air tank as shown in FIG. ) And the second output port C2 are connected.

Moreover, the 2nd side (output port C1) of the 1st piston valve B1 and the 2nd side (2nd output port C2) of the 2nd piston valve B2 are respectively made into the 1st check valve D1 and 1st. While connecting to the secondary chamber A2 via two supply paths by the second check valve D2, a third check valve D3 and a fourth check valve D4 and a third piston are connected to the secondary chamber A2. The third output port C3 and the fourth output port C4 are connected via the valve B3 and the fourth piston valve B4.

Therefore, the air supplied to the primary chamber A1 is sent to the 1st output port C1 and the 2nd output port C2 via the 1st piston valve B1 and the 2nd piston valve B2. At the same time, a part of the air sent from the 1st piston valve B1 and the 2nd piston valve B2 passes the supply path by the 1st check valve D1 and the 2nd check valve D2, and the secondary chamber A2. Put in The third check valve D3 and the third piston valve B3 are passed from the secondary chamber A2 to the third output port C3, and the fourth check valve D4 and the fourth piston valve are also provided. It is sent to the fourth output port C4 via (B4). In Fig. 12, reference numerals E1, E2 and F1, F2 denote orifices and check valves connecting the primary side and the secondary side of the first piston valve B1 and the second piston valve B2.

(Patent Document 1) Japanese Unexamined Patent Publication No. 2000-264193

However, in the four-circuit protection valve shown in FIG. 12, a space for accommodating the first check valve D1 and the second check valve D2, and flow holes G1, G2 and H3 for closing by these valves, In order to form H4), the drilling operation must be performed from the left and right directions of the valve body 100 in FIG. 12. By the way, since the other member is arrange | positioned at the right and left sides of a check valve, such a perforation operation is technically difficult, for example, even if it is possible, it costs enormous cost.

In this case, in practice, the left and right both sides of the position shown by the imaginary line K in FIG. 12 are divided into two parts, and the space for storing the check valves D1 and D2 and the distribution holes G1, G2 and H3 are provided. And H4, after forming the check valve, the two parts are fastened with bolts V1 and V2 to form the valve body 100. However, in such a two-divided structure, not only does the management cost increase due to the increase in the number of parts, the manufacturing process becomes complicated, but there is also a problem in strength.

Accordingly, an object of the present invention is to provide a four-circuit protection valve capable of reducing the number of parts and maintaining a strong strength as a whole.

In order to achieve the said subject, the 4th circuit protection valve which concerns on the 1st aspect of this invention is the 1st chamber connected to an inlet port, and the 1st chamber connected with the said 1st chamber, respectively through the 1st valve part and the 2nd valve part, A second chamber connected to a first output port and a second output port, the first output port and the second output port through a first check valve portion and a second check valve portion, and the second chamber and a third valve portion, respectively. And a valve body having a third output port and a fourth output port connected via a fourth valve portion, wherein the valve body extends in the first axial direction and the second axial direction, respectively. A check valve for forming the first body portion and the second body portion which is formed as a single body of the shape bent entirely in the bent, the first check valve portion and the second check valve portion A and from the outer wall of the bend being formed in the accessible location rather than through the other member.

Moreover, the 4th circuit protection valve which concerns on the 2nd aspect of this invention is the 1st output port connected with the inlet port, the 1st output port connected with the said 1st chamber via the 1st valve part, and the 2nd valve part, respectively, A second seal connected to the second output port, the first output port and the second output port via a first check valve portion and a second check valve portion, and the third seal and the third valve portion and the fourth valve portion, respectively. The valve body provided with the 3rd output port and the 4th output port connected via the said 1st valve part and the 2nd valve part, A 1st valve body and a 2nd valve body are respectively a 1st valve seat and a 2nd valve body. The first valve body and the second valve body are respectively the first valve seat and the second valve body when the valve seat is always pressed and pressurized in the direction of closing the communication by the connection, and the inside of the first chamber is at a predetermined pressure or more. Valve seat Apart from each other, each of the first and second output ports is openable to communicate with the first and second output ports, wherein the first check valve portion is pressed by the first check valve seat and the first valve portion is opened. The first check valve body is openable so as to communicate with the second chamber away from the first check valve seat, and the second check valve part is pressed by the second check valve seat. When the second valve portion is opened, the second check valve body is openable so as to communicate with the second chamber away from the second check valve seat, and the third valve portion and the fourth valve portion are respectively the third valve body. And the fourth valve body is pressed against the third valve seat and the fourth valve seat at all times to close the communication by the connection, and the inside of the second chamber is above a certain pressure. In this case, the third valve body and the fourth valve body are openable to communicate with the third output port and the fourth output port, respectively, away from the third valve seat and the fourth valve seat, and the valve body is And a single body having a shape that is bent entirely in the bent portion so as to form a first body portion and a second body portion extending in the first axial direction and the second axial direction, respectively, wherein the first check valve portion and the second check valve portion are installed. The opening for the check valve is formed at a position accessible from the outer wall of the bent portion without passing through other members.

According to the first or second aspect of the present invention, it is not necessary to divide the valve body in order to form a hole for installing a check valve as in the prior art, and to directly drill from the outer wall of the bent portion of the valve body made of a single body. The hole drilling operation can be performed. Therefore, it is possible to provide a valve body, i.e., a four-circuit protection valve, which maintains a high strength without increasing the number of parts.

Moreover, in the 4th circuit protection valve which concerns on the 3rd aspect of this invention, in the said 1st or 2nd aspect, the said bending part is bent in the direction orthogonal to a 1st axial direction and a 2nd axial direction, It is characterized by the above-mentioned. will be. According to this aspect, the opening for a check valve can be easily formed in a 1st axial direction or a 2nd axial direction by a drill etc. from the outer wall of a curved part.

Moreover, in the 4th circuit protection valve which concerns on the 4th aspect of this invention, in the said 1st or 2nd aspect, the said bend part is bent so that a 1st axial direction and a 2nd axial direction may cross at an obtuse angle, It is characterized by the above-mentioned. will be. According to the present invention, the change in the overall shape of the four-circuit protection valve becomes wider, and the crossing angle between the first axial direction and the second axial direction can be set according to the intended use.

Moreover, in the 4th circuit protection valve which concerns on the 5th aspect of this invention, in any one of said 2nd-4th aspect, the said 1st valve part and the 2nd valve part are located in the vicinity of the 1st end part separated from the said bend part. A first valve body and a second valve body arranged and movable in a direction orthogonal to a surface made in the first axial direction and the second axial direction, wherein the third valve portion and the fourth valve portion are the bent portions. And a third valve body and a fourth valve body disposed near the second end portion away from the second end and movable in a direction orthogonal to a surface made in the first axial direction and the second axial direction. According to this aspect, it is possible to provide a compact 4-circuit protection valve as a whole.

Moreover, in the 4th circuit protection valve which concerns on the 6th aspect of this invention, in any one of said 2nd-5th aspect, a said 1st valve part, a 2nd valve part, a 3rd valve part, and a 4th valve part A pressure medium flow path region composed of the first chamber, the second chamber, and the like in the valve body, and the first valve body, the second valve body, the third valve body, and the fourth valve body in each of these valve parts are closed. It characterized by having a diaphragm partitioning the arrangement | positioning area of each pressurizing means which presses in a direction. According to this aspect, each valve part can be structured simply.

In the sixth aspect, the four-circuit protection valve according to the seventh aspect of the present invention is the first valve portion and the second valve portion on the pressure medium flow path region side of the diaphragm. The first reinforcement valve portion and the second reinforcement valve portion, which are folded to the second valve seat and open and close the pressure medium flow path, are further provided. As a result, the opening and closing operations of the first valve portion and the second valve portion disposed upstream of the third valve portion and the fourth valve portion with respect to the flow direction of the pressure medium can be performed with high accuracy, and the whole opening and closing is performed. The operation can be realized with high precision.

(The best form to carry out invention)

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. 1 is a perspective view of a four-circuit protection valve according to the present invention.

2 is a schematic diagram for explaining the role of the four-circuit protection valve. Fig.3 (a) (b) is operation explanatory drawing which shows two aspects at the time of valve opening of a 4 circuit protection valve. (A), (b) and (c) of FIG. 4 respectively show the 4 circuit protection valves from the IV (a) direction of FIG. 1, the 4 circuit protection valves from the IV (b) direction, and FIG. CC line sectional drawing of (b).

FIG. 5 is a view of the four circuit protection valve from the V direction of FIG. 1. FIG. 6 is a view of the four circuit protection valve from the VI direction of FIG. 1. FIG. FIG. 7 is a view of the four circuit protection valve from the VII direction of FIG. 1. FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG. 7. Fig. 9 is a sectional view taken along the line IX-IX in Fig. 4A. 10 is a cross-sectional view taken along line X-X of FIG. 7. 11 is a circuit diagram of a four circuit protection valve.

As shown in FIG. 1, the four-circuit protection valve 1 (hereinafter simply referred to as the valve 1) is composed mainly of the valve body 3, and the valve body 3 is each configured in the present embodiment. The first main body portion 9 and the second main body portion 11 extending in the first axial direction 5 and the second axial direction 7 in an orthogonal relationship are formed as a unitary body by integral molding. . Examples of the material of the valve body 3 include aluminum materials, polyacetal (POM) materials and nylon materials which are synthetic resins. The 1st main body part 9 and the 2nd main body part 11 are integrated by the bending part 13, as shown in FIG. Therefore, the valve main body 3, that is, the valve 1, is a single body of a shape bent in an L shape as a whole in this embodiment, and is formed by the injection molding method. The valve body 3 having a single-piece structure having such a curved shape is a structure which does not exist in this type of valve in the prior art, and is a part of the characteristic configuration of the present invention. This point will be described later in detail.

In FIG. 1, 4A is a cover of the 1st valve part 25 mentioned later, 4B is a cover of the 2nd valve part 27 mentioned later, 4C is a cover of the 3rd valve part 67 mentioned later, and 4D shows a cover of the fourth valve section 69 described later.

Before explaining the characteristic configuration of the present invention, the method (role) of the valve 1 will be described first based on FIG. As shown in FIG. 2, the valve 1 constitutes a part of the air pressure supply mechanism of the vehicle, and is supplied from the air compressor 15 to supply compressed air through the air dryer 17 of the present invention. It distributes to four air accumulators 19a-19d as an example through the valve 1. As shown in FIG. The valve 1 has a function of preventing decompression to other air accumulators even when air leakage occurs in any one of the four air accumulators 19a to 19d.

Next, the basic structure of the said valve 1 and its operation principle are demonstrated based on the operation | movement explanatory drawing of FIG. As shown in FIG. 3, the valve 1 includes a first chamber 21 and a second chamber 23 therein, and the first chamber 21 is connected to the inlet port 22. Two valve parts, that is, the first valve part 25 and the second valve part 27, are formed in the first chamber 21. The 1st valve part 25 is equipped with the movable 1st valve body 29 and the 1st valve seat 31 which is always pressed by the coil spring 41 which is the pressurizing member. The second valve portion 27 is a second valve seat 33 which is always pressed by the movable second valve body 30 and the coil spring 41 which is another pressurizing member. Equipped)

The first valve body 29 and the second valve body 30 are each valve seat (when the pressure in the first chamber 21 is greater than a predetermined pressure) when the pressure in the first chamber 21 is greater than the pressing force of the coil spring 41 ( The valve sections 25 and 27 are opened apart from the sections 31 and 33. In Fig. 3, reference numeral 37 denotes an air opening port, and the air opening port 37 is for air opening the coil spring chamber 39.

On the downstream side of the first valve portion 25 and the second valve portion 27, the first output port 47 and the second output port 49 through the first flow passage 43 and the second flow passage 45, respectively. Is formed. In place of the first flow passage 43 and the second flow passage 45 that are connected to the first output port 47 and the second output port 49, the first check valve portion 51 and the second check valve portion, respectively. 53 is formed. The first check valve section 51 has a first check valve seat 57 in which the movable first check valve body 55 and the first check valve body 55 are pressed by the coil spring 42 to be pressed. The second check valve portion 53 is a second check valve seat 59 in which the movable second check valve body 59 and the second check valve body 59 are pressed and pressed by another coil spring 42 ( 61). The downstream side of the 1st check valve part 51 and the 2nd check valve part 53 is joined in the 3rd flow path 63, and this 3rd flow path 63 communicates with the 2nd chamber 23. As shown in FIG. When the pressure in the 1st output port 47 and the 2nd output port 49 is larger than the pressure of the 2nd chamber 23, respectively, in the 1st check valve body 55 and the 2nd check valve body 59, respectively, Only the check valve parts 51 and 53 are opened apart from the first check valve seat 57 and the second check valve seat 61.

Two valve parts, that is, a third valve part 67 and a fourth valve part 69, are formed in the second chamber 23. The third valve portion 67 includes a movable third valve body 71 and a third valve seat 73 on which the third valve body 71 is pressed, and the fourth valve portion 69 is movable. The 4th valve body 75 and the 4th valve seat 77 by which the 4th valve body 75 is pressed are provided. The third valve body 71 and the fourth valve body 75 have the same configurations as the first valve body 29 and the second valve body 30.

Downstream of the third valve portion 67 and the fourth valve portion 69, the third output port 83 and the fourth output port 85 through the fourth flow path 79 and the fifth flow path 81, respectively. Is formed. The first output port 47, the second output port 49, the third output port 83, and the fourth output port 85 are connected to the air accumulators 19a to 19d in Fig. 2, respectively. 3, the said cover 4A, 4B, 4C, 4D of each said valve part 25, 27, 67, 69 is abbreviate | omitted.

The above is the basic principle structure inside the valve 1, and the action is demonstrated below. When air pressure is supplied from the air compressor 15 to the air accumulators 19a to 19d, the pressure at the inlet port 22 is reduced by the first valve portion 25 and as shown in Fig. 3 (a). Since it exceeds the pressing force of the coil spring 41 which closes the 2nd valve part 27, the 1st valve body 29 and the 2nd valve body 30 fall from each valve seat 31,33, and pressurized air Is supplied to the air accumulators 19a and 19b through the first output port 47 and the second output port 49. This pressure also acts on the first check valve section 51 and the second check valve section 53 to open these valve sections 51 and 53, thereby allowing the third valve section 67 and the fourth valve section 69 to be opened. The third valve body 71 and the fourth valve body 75 are separated from the valve seats 73 and 77, and the compressed air passes through the third output port 83 and the fourth output port 85 It is also supplied to the air accumulators 19c and 19d. When the operation of the air compressor 15 is stopped, the valve sections 25, 27, 67, and 69 and the check valve sections 51 and 53 are closed so that the constant air pressure in the air accumulators 19a to 19d is accumulated. It becomes a state.

For example, in the process of supplying the compressed air as described above, assuming that a hole causing air leakage is formed in the air accumulator 19a, the first output port 47 passing through the air accumulator 19a is provided. The pressure is lower than the pressure at the second output port 49, the third output port 83, and the fourth output port 85 through the other air accumulators 19b to 19d due to air leakage. When the air compressor 15 is operated in this state, the second valve body 30, the third valve body 71 and the fourth valve body 75 are caught from the output ports 49, 83, 85 on each side. Since the pressure is larger than the pressure applied to the first valve body 29 from the first output port 47 (pressure drop due to air leakage), as shown in Fig. 3B, the second valve body ( 30) and the 3rd valve body 71 and the 4th valve body 75 operate | move so that each valve part 27, 67, 69 may open earlier than the 1st valve body 29. FIG. Therefore, with respect to the air accumulators 19b to 19d, compressed air is filled in preference to the air accumulator 19a, so that the function thereof can be maintained. On the other hand, the first valve portion 25 is also opened thereafter, and compressed air is supplied toward the air accumulator 19a. The pressure at the first output port 47 decreases instantly due to the air leakage, and immediately The first valve portion 25 is to be closed.

The driver who notices the air leakage of the air accumulator 19a by the alarm lamp etc. can move using the air pressure of the air accumulators 19b-19d while driving to the gas station etc. which are close in this state. As a result, air leakage of the air accumulator 19a can be repaired at the gas station.

Next, the characteristic structure of the valve 1 which concerns on this invention is demonstrated based on FIG. 1, FIG. 4 (a) (b) (c), and FIGS. In addition, about the basic structure and functional part which were demonstrated in FIG. 3, the same code | symbol is attached | subjected to the corresponding part in each figure, and the description is abbreviate | omitted. As described above, the valve body 3 has a bent portion to form a first body portion 9 and a second body portion 11 extending in the first axial direction 5 and the second axial direction 7, respectively. In Fig. 13, the shape is bent entirely.

The check valve openings 54 and 54 for installing the first check valve part 51 and the second check valve part 53 are as shown in Figs. 1, 4 (c) and 7. Likewise, the outer wall 87 of the bent portion 13 is formed at an accessible position without passing through other members. That is, the check valve openings 54 and 54 are formed at positions where drilling can be performed directly from the outer wall 87 of the bent portion 13 by a drill or the like. The check valve openings 54 and 54 are formed so as to communicate with the first chamber 21 as shown in Figs. 4 (c) and 7. In addition, from another outer wall 88 of the bent portion 13, a check valve opening for establishing communication with the second chamber 23 at a position where a punching operation can be directly performed through a drill or the like without passing through other members. (64, 64) are formed. The openings 54 and 64 for both check valves are formed so as to communicate naturally. 8, the 1st check valve part 51 and the 2nd check valve part 53 are provided in the bending part 13 with the same structure.

By adopting such a configuration, the check valve openings 54 and 64 do not need to divide a member in order to form an opening for check valve arrangement as in the prior art, and the outer walls 87 and 88 of the bent portion 13 do not need to be divided. It can form by performing a punching | drilling operation | work directly from a drill etc. directly. By arranging the check valves 51 and 53 in such a perforated portion, the valve body 3 can be formed in a single body without being divided. Thereby, the four-circuit protection valve which consists of the valve main body 3 which did not increase the number of components and maintained strong intensity | strength can be provided. 4 (c) and 7, reference numeral 72 denotes a steel ball that blocks the inlet of the check valve opening 64, and in FIG. 8, reference numerals 74 and 74 block the inlet of the check valve opening 54. Support ring. Reference numeral 76 denotes a check valve stopper, and reference numeral 78 denotes an O-ring for sealing.

In the present embodiment, the first valve portion 25, the second valve portion 27, the third valve portion 67 and the fourth valve portion 69 are the first in the valve body 3. The pressure medium (air) flow path region composed of the chamber 21, the second chamber 23, and the like, and the first valve body 29, the second valve body 30, and the third in each of these valve sections. The diaphragm 35 which partitions the arrangement | positioning area of the valve body 71, the 4th valve body 75, and each coil spring 41 which presses these in the closing direction is provided as shown to FIGS. 8-10. It is. The first valve portion 25 and the second valve portion 27 are connected to the first valve seat 31 and the second valve seat 33 on the pressure medium flow path region side of the diaphragm 35. The first reinforcement valve portion 101 and the second reinforcement valve portion 107, which fold to open and close the pressure medium flow path, are further provided as shown in Figs. The 1st strengthening valve part 101 and the 2nd strengthening valve part 107 have the same structure, and are the valve body 101, the valve sealing part 102 provided in this valve body 101, and this valve body. The orifice valve 103 and the orifice spring 104 which are provided in 101 are comprised. A portion of the valve seal 102 is pressed against the valve seats 31 and 33 to close the flow path.

Thereby, opening and closing of the said 1st valve part 25 and the 2nd valve part 27 arrange | positioned upstream rather than the 3rd valve part 67 and the 4th valve part 69 with respect to the flow direction of a pressure medium. The operation can be performed with high accuracy, and therefore the entire opening and closing operation can be realized with high accuracy.

In the above embodiment, the first axial direction 5 and the second axial direction 7 are orthogonal to each other, so as to realize a hole drilling operation of the opening for the check valve from the outer walls 87 and 88 of the bent portion 13. The bend may be curved such that the first axial direction and the second axial direction intersect at an obtuse angle.

In the above embodiment, the first valve portion 25 and the second valve portion 27 are disposed near the first end portion 91 away from the bend portion 13, and the first axial direction 5 is also provided. And a first valve body 29 and a second valve body 30 which are movable in a direction orthogonal to a surface made in the second axial direction 7, wherein the third valve portion 67 and the fourth valve body are provided. The valve portion 69 is disposed near the second end portion 89 away from the bend portion 13 and in a direction orthogonal to a surface made in the first axial direction 5 and the second axial direction 7. And a third valve body 71 and a fourth valve body 75 that are movable. By adopting such a configuration, the compact valve 1 can be provided as a whole.

According to the present invention, it is not necessary to divide the valve body in order to form a hole for installing a check valve as in the related art, and a drilling operation can be performed directly from the outer wall of the bent portion of the valve body made of a single body by a drill or the like. . Therefore, it is possible to provide a four-circuit protection valve having a valve body which does not increase the number of parts and maintains a strong strength.

1 is a perspective view of a four-circuit protection valve of the present invention.

2 is a schematic view for explaining the operation of the four-circuit protection valve.

FIG. 3: (a) (b) is operation explanatory drawing which shows two aspects at the time of valve opening of a 4 circuit protection valve.

4 is a view of the four circuit protection valve from the IV (a) direction of Fig. 1, (b) is a view of the four circuit protection valve from the IV (b) direction, (c) is (b) CC line cross-sectional view.

FIG. 5 is a view of the four circuit protection valve from the V direction of FIG. 1.

FIG. 6 is a view of the four circuit protection valve from the VI direction of FIG. 1. FIG.

FIG. 7 is a view of the four circuit protection valve from the VII direction of FIG. 1.

FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG. 7.

FIG. 9 is a sectional view taken along the line IX-IX of FIG. 4 (a).

10 is a cross-sectional view taken along line X-X of FIG. 7.

11 is a circuit diagram of a four circuit protection valve.

12 is a longitudinal sectional view of a conventional four-circuit protection valve.

(Explanation of the sign)

1 4 Circuit Protection Valve 3 Valve Body

5 1st axial direction 7 2nd axial direction

9 First body part 11 Second body part

13 Bend 15 Air Compressor

17 Air Dryer 19a ~ 19d Air Accumulator

21 1st room 22 Entrance port

23 2nd chamber 25 1st valve part

27 2nd valve part 29 1st valve body

30 2nd valve body 31 1st valve seat

33 2nd valve seat 35 Diaphragm

37 openings 39 spaces

41 coil spring 43 1st flow path

45 2nd Euro 47 1st Output Port

49 2nd output port 51 1st check valve part

53 2nd check valve part 54 Opening for check valve

55 1st check valve body 57 1st check valve seat

59 Second check valve body 61 Second check valve seat

63 3rd flow path 67 3rd valve part

69 4th valve part 71 3rd valve body

73 3rd valve seat 75 4th valve body

77 4th valve seat 79 4th flow path

81 5th Euro 83 3rd Output Port

85 Fourth output port 87 Outer wall of the bend

89 second end away from the bend in the first axial direction

91 first end away from the bend in the second axial direction

Claims (7)

The first chamber connected to the inlet port, A first output port and a second output port connected to the first chamber via a first valve portion and a second valve portion, respectively; A second seal connected to the first output port and the second output port via a first check valve portion and a second check valve portion, respectively; A four-circuit protection valve comprising a valve body having a third output port and a fourth output port connected to the second seal via a third valve portion and a fourth valve portion, respectively. The valve body is formed as a single body having a shape that is bent entirely in the bent portion so as to form a first body portion and a second body portion extending in the first axial direction and the second axial direction, respectively, the first check valve portion and the second 4. A four-circuit protection valve, wherein an opening for a check valve for installing a check valve portion is formed at a position accessible from an outer wall of the curved portion without passing through another member. The first chamber connected to the inlet port, A first output port and a second output port connected to the first chamber via a first valve portion and a second valve portion, respectively; A second seal connected to the first output port and the second output port via a first check valve portion and a second check valve portion, respectively; And a valve body having a third output port and a fourth output port connected to the second chamber via a third valve portion and a fourth valve portion, respectively. The first valve portion and the second valve portion are pressed in a direction in which the first valve body and the second valve body are always pressed against the first valve seat and the second valve seat, respectively, to close the communication by the connection. When the inside of the first chamber is above a certain pressure, the first valve body and the second valve body are separated from the first valve seat and the second valve seat, respectively, so that they can communicate with the first output port and the second output port, respectively. Openable, The first check valve portion is in communication with the second chamber away from the first check valve seat when the first check valve member is pressed against the first check valve seat and the first valve portion is opened. And the second check valve part is separated from the second check valve seat when the second check valve body is pressed by the second check valve seat and the second valve part is opened. Openable to communicate with the second room, The third valve portion and the fourth valve portion are pressed in the direction in which the third valve body and the fourth valve body are always pressed against the third valve seat and the fourth valve seat to close the communication by the connection, respectively. When the inside of the chamber is at a certain pressure or higher, the third valve body and the fourth valve body are separated from the third valve seat and the fourth valve seat, respectively, so that they can communicate with the third output port and the fourth output port, respectively. Openable, The valve body is formed as a single body having a shape that is bent entirely in the bent portion so as to form a first body portion and a second body portion extending in the first axial direction and the second axial direction, respectively, the first check valve portion and the second A four-circuit protection valve is provided with a check valve opening for installing a check valve portion at a position accessible from an outer wall of the bent portion without passing through another member. The four-circuit protection valve according to claim 1 or 2, wherein the bent portion is bent in a direction orthogonal to the first and second axial directions. The four-circuit protection valve according to claim 1 or 2, wherein the bent portion is bent such that the first axial direction and the second axial direction intersect at an obtuse angle. The surface according to any one of claims 2 to 4, wherein the first valve portion and the second valve portion are disposed near the first end portion away from the bent portion, and are made in the first axial direction and the second axial direction. A first valve body and a second valve body movable in a direction orthogonal to the second valve body, wherein the third valve portion and the fourth valve portion are disposed near a second end portion away from the bent portion, and further comprising the first axial direction and the first valve body. A four-circuit protection valve comprising a third valve body and a fourth valve body movable in a direction orthogonal to a surface made in two axial directions. The pressure medium according to any one of claims 1 to 4, wherein the first valve portion, the second valve portion, the third valve portion, and the fourth valve portion are composed of the first chamber, the second chamber, and the like in the valve body. The diaphragm which partitions a flow path area | region and the arrangement | positioning area of the said 1st valve body, the 2nd valve body, the 3rd valve body, the 4th valve body in these valve parts, and each pressurizing means which presses these in the direction which closes them is made. Four-circuit protection valve characterized by having. 7. The first reinforcement of claim 6, wherein the first valve portion and the second valve portion are connected to the first valve seat and the second valve seat on the pressure medium flow path region side of the diaphragm to open and close the pressure medium flow path. A four-circuit protection valve further comprising a valve portion and a second reinforcement valve portion.