JP2014167327A - Differential pressure valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a convenient structure of a differential pressure valve in which a valve opening pressure can be increased as a pressure of working fluid guided is increased.SOLUTION: There is provided a differential valve 1 opened or closed in response to a differential pressure ΔP between an upstream side pressure P1 and a downstream side pressure P2. This differential pressure valve 1 comprises an upstream side pressure chamber 13 to which the upstream side pressure P1 is guided, a downstream side pressure chamber 14 to which the downstream side pressure P2 is guided, a valve 6 abutted against a seat part 9A to part the upstream side pressure chamber 13 and the downstream side pressure chamber 14, a piston 8 for parting the upstream side pressure chamber 13 and an external side to which the external pressure (atmospheric pressure) is guided and a piston rod 7 (a piston connecting part) for connecting the piston 8 to the valve 6, and a differential pressure between the upstream side pressure P1 and the external pressure biases the piston 8 to close the valve 6.

Description

  The present invention relates to a differential pressure valve that opens and closes according to a differential pressure between an upstream pressure and a downstream pressure of a working fluid.

  The rail spring air spring suspension system adjusts the pressure of the pressurized air (working fluid) guided to the left and right first air springs, the second air spring, and the first air spring and the second air spring that suspend the axle. And a first differential pressure valve and a second differential pressure valve that communicate with each other according to a pressure difference between the first air spring and the second air spring.

  When the loading weight of the vehicle increases or decreases, pressurized air is supplied to and discharged from the first air spring and the second air spring by the height adjustment valve, and the vehicle height is automatically adjusted according to the vehicle weight.

  When one of the first air spring and the second air spring becomes high pressure due to the inclination of the vehicle, etc., one of the first differential pressure valve and the second differential pressure valve opens, and the high pressure of one air spring It is guided to the air spring and automatically adjusted so that the vehicle body does not tilt significantly.

  By the way, in the curve where the rail (track) bends, a centrifugal force acts on the vehicle, and therefore, a cant amount is set to make the rail height different so that the rail outside the curve is higher than the rail inside the curve. This eliminates the load difference between the inside and the outside that occurs when the vehicle is traveling on a curve.

  When the vehicle runs at a low speed or stops on a curve with a cant amount set, the load on the inside of the curve increases as the centrifugal force of the vehicle decreases, and the left and right first air springs, The differential pressure of the two air springs increases.

  In such a case, if the set value of the valve opening pressure of the differential pressure valve is low, one of the first differential pressure valve and the second differential pressure valve opens, and a cant loss phenomenon occurs in which the inclination of the vehicle body cannot be restored.

  The Kant defeat phenomenon is, for example, as the first air spring is compressed due to the inclination of the vehicle body, the first differential pressure valve opens, and the air of the first air spring is guided to the second air spring, When the air of the second air spring in the extended state is exhausted from the height adjustment valve, the air of the first air spring is exhausted from the second air spring via the first differential pressure valve. This is a phenomenon in which the tilt of the vehicle body cannot be restored.

  As a measure for preventing the Kant defeat phenomenon, Patent Document 1 discloses an air spring type suspension device in which the valve opening pressure of the differential pressure valve is increased as the vehicle weight (pressure of the air spring) increases. ing.

  In this differential pressure valve, a closed diaphragm and an open diaphragm are respectively attached to the valve body and the housing, and an atmospheric pressure chamber is defined between them. The pressure of the air spring guided around the valve body and each diaphragm As the valve rises, the valve opening pressure is increased.

  As a result, in the air spring type suspension device, the valve opening pressure of the differential pressure valve is increased as the pressure of the air spring increases when the vehicle weight increases, and the cant loss phenomenon is prevented.

JP 2002-120723 A

  However, in such a differential pressure valve of Patent Document 1, two diaphragms are respectively attached across the housing and the valve body, and an atmospheric pressure chamber is defined between the diaphragms, so that the structure becomes complicated. There was a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a differential pressure valve that can increase the valve opening pressure with a simple structure as the pressure of the guided working fluid increases.

  In the differential pressure valve that opens and closes according to the differential pressure between the upstream pressure and the downstream pressure of the working fluid, the present invention guides the upstream pressure chamber to which the upstream pressure of the working fluid is guided and the downstream pressure of the working fluid. A downstream pressure chamber, a seat portion provided between the upstream pressure chamber and the downstream pressure chamber, a valve that contacts the seat portion to partition the upstream pressure chamber and the downstream pressure chamber, an upstream pressure chamber, and an external pressure (atmospheric pressure) A piston for partitioning the outside to be guided and a piston connecting part for connecting the piston to the valve are provided, and the piston biases the valve toward the closing side by a differential pressure between the upstream pressure and the external pressure.

  In the differential pressure valve of the present invention, the piston urges the valve to close by the differential pressure between the upstream pressure of the working fluid and the external pressure, so that the valve is removed from the seat portion as the upstream pressure of the working fluid increases. The valve opening pressure which leaves is increased.

  The differential pressure valve has a simple structure in which the upstream pressure chamber and the outside are partitioned by a piston, and an atmospheric pressure chamber is defined by interposing two diaphragms inside the housing like the device described in Patent Document 1. There is no need to do.

It is sectional drawing of the differential pressure | voltage valve unit which concerns on 1st Embodiment of this invention. It is sectional drawing of the differential pressure | voltage valve which concerns on 1st Embodiment of this invention. It is sectional drawing of the differential pressure valve which concerns on 2nd Embodiment of this invention. It is sectional drawing of the differential pressure | voltage valve which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
In FIG. 1, a first air spring 21 and a second air spring 22 are provided in an air spring type suspension device of a railway vehicle, and suspend an axle via a carriage on the left and right sides of a vehicle body (not shown).

  The differential pressure valve unit 10 is provided in an air spring type suspension device, and generates a differential pressure ΔP between the pressure P1 of air (working fluid) guided from the first air spring 21 and the pressure P2 of air guided from the second air spring 22. It operates to keep below the set value.

  The differential pressure valve unit 10 is directed from the first series passage 3 communicating with the first air spring 21, the second communication path 4 communicating with the second air spring 22, and from the first series passage 3 to the second communication path 4. A first differential pressure valve 1 that controls the flow of air and a second differential pressure valve 2 that controls the flow of air from the second communication path 4 to the first series path 3 are provided.

  When the first air spring 21 is compressed by the inclination of the vehicle body, and the pressure P1 of the first air spring 21 rises beyond the set value by the pressure P2 of the second air spring 22, the first differential pressure valve 1 opens. Then, the air from the first air spring 21 is guided to the second air spring 22 through the first series passage 3 and the second communication passage 4 as indicated by black arrows in the drawing. On the other hand, when the second air spring 22 is compressed and the pressure P2 of the second air spring 22 rises above the set value from the pressure P1 of the first air spring 21, the second differential pressure valve 2 opens, The air from the second air spring 22 is guided to the first air spring 21 through the second communication path 4 and the first series path 3 as indicated by white arrows in the figure. In the air spring type suspension device, the pressure P1 of the first air spring 21 and the pressure P2 of the second air spring 22 are automatically adjusted by the operation of the differential pressure valve unit 10 so that the vehicle body does not tilt significantly.

  The first differential pressure valve 1 and the second differential pressure valve 2 have the same basic configuration. The first differential pressure valve 1 (hereinafter simply referred to as “differential pressure valve 1”) will be described with reference to FIG.

  A housing 20 provided in the differential pressure valve 1 accommodates a valve 6 that opens and closes the first series passage 3, a valve seat 9 that contacts the valve 6, and a spring 5 that presses the valve 6 against the valve seat 9. .

  In FIG. 2, O is the central axis of the cylindrical valve 6. A guide portion 25 extending in the axial direction is formed in the housing 20. The valve 6 is slidably inserted into the guide portion 25 and is accommodated in the housing 20 so as to be movable in the axial direction. The “axial direction” means a direction in which the central axis O of the valve 6 extends.

  The valve 6 has annular outer peripheral flange portions 6 </ b> A and 6 </ b> B that are in sliding contact with the guide portion 25 of the housing 20. A plurality of notches 6C and 6D are formed in the annular outer peripheral flange portions 6A and 6B, respectively. In the figure, spaces defined above and below the valve 6 communicate with each other via notches 6C and 6D.

  The cylindrical valve seat 9 has a seat portion 9A that is interposed in the housing 20 and protrudes in an annular shape. The valve seat 9 may be formed integrally with the housing 20 without being limited thereto.

  The valve 6 is provided with a packing 18 made of an elastic material such as a rubber material at a portion facing the seat portion 9A. The valve 6 is closed when the disc-shaped packing 18 abuts against the seat portion 9 </ b> A of the valve seat 9 and closes between the first series passage 3 and the second communication passage 4. On the other hand, the valve 6 is opened when the packing 18 is separated from the seat portion 9 </ b> A of the valve seat 9, and the first series passage 3 and the second communication passage 4 are communicated.

  In addition, it is not restricted to the structure mentioned above, the packing 18 interposed by the valve | bulb 6 is abolished, and the main body of the valve | bulb 6 contact | abuts directly to the sheet | seat part 9A, Between the 1st serial passage 3 and the 2nd communicating path 4 It is good also as a structure which closes.

  The internal space of the housing 20 is partitioned into an upstream pressure chamber 13 and a downstream pressure chamber 14 by the valve seat 9 and the valve 6. The upstream pressure chamber 13 communicates with the second air spring 22 through the first series passage 3, and the pressure P2 of the second air spring 22 is guided. The downstream pressure chamber 14 communicates with the first air spring 21 through the second communication passage 4 and the pressure P1 of the first air spring 21 is guided.

  The valve 6 has an opening-side pressure receiving surface 6 </ b> G facing the upstream pressure chamber 13 facing the inside of the seat portion 9 </ b> A of the valve seat 9. The valve 6 is urged in the opening direction away from the seat portion 9A by the pressure P1 of the first air spring 21 acting on the opening-side pressure receiving surface 6G.

  The valve 6 has a closed pressure receiving surface 6 </ b> F that faces the downstream pressure chamber 14. The closing side pressure receiving surface 6F and the opening side pressure receiving surface 6G are divided according to the portion that contacts the seat portion 9A of the valve seat 9. The valve 6 is biased in the closing direction in contact with the seat portion 9A by the pressure P2 of the second air spring 22 acting on the closing side pressure receiving surface 6F.

  The valve 6 has a spring receiving portion 6E that receives the spring force of the spring 5 on the closing side pressure receiving surface 6F. The spring receiving portion 6E is formed so as to be recessed in the inner side of the outer peripheral flange portion 6A.

  The coiled spring 5 is compressed and interposed between the spring receiving portion 6E and the cap 19 attached to the housing 20. The spring 5 is arranged coaxially with the valve 6 by being inserted into a spring receiving portion 6E whose end is recessed in a concave shape.

  During normal operation of the vehicle, the differential pressure ΔP (= P1−P2) between the pressure P1 of the first air spring 21 and the pressure P2 of the second air spring 22 acting on the valve 6 is kept lower than the valve opening pressure. The valve 6 is brought into contact with the seat portion 9A to close the valve, and the first series passage 3 and the second communication passage 4 are blocked.

  When the first air spring 21 is compressed due to the inclination of the vehicle body, a differential pressure ΔP between the first air spring 21 and the second air spring 22 acting on the valve 6 is generated. When the differential pressure ΔP increases beyond the valve opening pressure, the valve 6 compresses the spring 5 and moves away from the seat portion 9A to open the valve. Thereby, in the differential pressure valve 1, the first series passage 3 and the second communication passage 4 are opened, and the air of the first air spring 21 is sent to the second air spring 22.

  The differential pressure valve 1 has a valve opening pressure adjustment mechanism that increases the valve opening pressure as the vehicle weight (pressure P1 of the first air spring 21) increases.

  As the valve opening pressure adjusting mechanism, the differential pressure valve 1 includes a piston 8 that partitions the upstream pressure chamber 13 and the outside from which atmospheric pressure is introduced as an external pressure, and a piston rod 7 that connects the piston 8 to the valve 6. .

  A cylinder portion 23 that accommodates the piston 8 is formed in the housing 20. The cylinder part 23 has a cylindrical inner wall centered on the central axis O, and both ends thereof open to the upstream pressure chamber 13 and the outside, respectively.

  The piston 8 is formed in a columnar shape centered on the central axis O, and is slidably inserted into the cylinder portion 23. The upstream pressure chamber 13 and the outside are partitioned by the piston 8 that is in sliding contact with the cylinder portion 23.

  The columnar piston rod 7 protrudes from the opening-side pressure receiving surface 6G facing the upstream pressure chamber 13 of the valve 6 and extends to the piston 8, and constitutes a piston connecting portion that connects the piston 8 to the valve 6. The piston rod 7 functions as a beam that supports the piston 8 on the valve 6. The columnar piston rod 7 connects the valve 6 and the piston 8, whereby the posture of the valve 6 is maintained by the piston 8, and the valve 6 moves smoothly during the opening / closing operation.

  An annular seal member 26 is provided between the cylinder portion 23 and the piston 8. An annular groove 24 in which a seal member 26 is interposed is formed in the middle of the cylinder portion 23. When the outer peripheral surface 8C of the piston 8 is in sliding contact with the seal member 26 without a gap, the sliding contact portion between the piston 8 and the cylinder portion 23 is sealed. The seal member 26 is an O-ring. The seal member 26 is not limited to the O-ring, and a seal ring having another cross-sectional shape may be used as appropriate.

  In addition, not only the structure mentioned above but it is good also as a structure by which a sealing member is directly attached to the outer periphery of piston 8. FIG. Moreover, it is good also as a structure which abolishes a sealing member and the outer periphery of piston 8 directly contacts the inner wall of the cylinder part 23 without a clearance gap.

  The valve 6, the piston rod 7, and the piston 8 are arranged on the central axis O and are formed symmetrically with respect to the central axis O. The valve 6, the piston rod 7 and the piston 8 are integrally formed with each other. However, the configuration is not limited to this, and the valve 6, the piston rod 7, and the piston 8 may be formed separately from each other.

  The piston 8 has an external pressure receiving surface 8B that is exposed to the outside from the cylinder portion 23 and receives the atmospheric pressure at the tip portion thereof. The pressure receiving area of the external pressure receiving surface 8 </ b> B is expressed as a cross-sectional area B of the piston 8 that is orthogonal to the central axis O of the piston 8.

  When the cross-sectional area perpendicular to the central axis O of the piston rod 7 is C, the cross-sectional area C is formed smaller than the cross-sectional area B. As a result, a closing side pressure receiving surface 8A for biasing the valve 6 toward the closing side is formed at the base end portion of the piston 8, and the pressure receiving area of the closing side pressure receiving surface 8A becomes (BC).

  When the closed pressure receiving surface 8A receives the upstream pressure P1 of the upstream pressure chamber 13, the valve 6 is biased to the closed side by the differential pressure between the upstream pressure P1 and the external pressure. The force by which the piston 8 receives the upstream pressure P1 and biases the valve 6 toward the closing side is expressed as P1 · (BC).

  Assuming that the cross-sectional area perpendicular to the axial direction of the piston rod 7 in the inner region of the portion of the valve 6 that contacts the seat portion 9A is A, the opening-side pressure receiving area that biases the valve 6 toward the opening side is expressed as AC. Is done.

Here, the force with which the valve 6 receives the differential pressure ΔP and is biased to the open side is expressed as ΔP (= P1−P2) · (AC). On the other hand, the force that biases the valve 6 toward the closing side is the sum of the spring force F of the spring 5 and the force P1 · (B−C) that biases the piston 8 toward the closing side, and the force acting on the differential pressure valve 1 is The relationship is:
ΔP · (A−C) = P1 · (B−C) + F (1)
From the above equation (1), the following equation is obtained.
ΔP = P1 · (BC) / (AC) + F / (AC) (2)
In the above equation (2), (B−C), (A−C), and F can be regarded as constants, so the differential pressure ΔP is a linear function with the pressure P1 of the first air spring 21 as a variable. . Therefore, when the pressure P1 increases, the differential pressure ΔP between the pressure P1 of the first air spring 21 and the pressure P2 of the second air spring 22 increases.

  Since the piston 8 is configured to partition the upstream pressure chamber 13 from the outside (atmospheric pressure), the force for biasing the valve 6 toward the closing side is increased, and the valve opening pressure of the valve 6 can be increased. When the vehicle body is tilted statically, the differential pressure valve 1 is difficult to open, and the cant loss phenomenon in which the vehicle body is largely tilted can be prevented.

  Further, when the vehicle weight is small, the pressure P1 of the first air spring 21 is small, and the differential pressure between the pressure P1 of the first air spring 21 and the atmospheric pressure is small, so the piston 8 biases the valve 6 toward the closing side. The power to do becomes smaller. Therefore, the differential pressure valve 1 is immediately opened by the differential pressure ΔP between the first air spring 21 and the second air spring 22, and the vehicle body can be prevented from tilting greatly.

  The second differential pressure valve 2 has the same configuration as that of the first differential pressure valve 1, and cant loss phenomenon can be prevented.

  According to the above 1st Embodiment, there exists an effect shown below.

  [1] In the differential pressure valve 1 that opens and closes according to the differential pressure ΔP between the upstream pressure P1 and the downstream pressure P2 of the working fluid, the upstream pressure chamber 13 into which the upstream pressure P1 of the working fluid is guided, and the downstream of the working fluid A downstream pressure chamber 14 through which the side pressure P2 is guided, a seat portion 9A provided between the upstream pressure chamber 13 and the downstream pressure chamber 14, and a valve that contacts the seat portion 9A and separates the upstream pressure chamber 13 and the downstream pressure chamber 14 from each other. 6, a piston 8 that partitions the upstream pressure chamber 13 from the outside from which external pressure (atmospheric pressure) is guided, and a piston rod 7 (piston coupling portion) that couples the piston 8 to the valve 6, and an upstream pressure P <b> 1. The piston 8 biases the valve 6 to the closing side by the differential pressure between the external pressure and the external pressure.

  According to the above configuration, the differential pressure valve 1 is configured so that the piston 8 biases the valve 6 to the closed side due to the differential pressure between the upstream pressure P1 of the working fluid and the external pressure, so that the upstream pressure P1 increases as the upstream pressure P1 increases. The valve opening pressure at which 6 separates from the seat portion 9A is increased. As a result, the cant losing phenomenon can be prevented when the vehicle weight increases.

  The differential pressure valve 1 has a simple structure in which the upstream side pressure chamber 13 and the outside are partitioned by a piston 8, and the atmospheric pressure chamber is defined inside the housing via two diaphragms as in the device described in Patent Document 1. There is no need to make it.

  [2] The differential pressure valve 1 includes an open pressure receiving surface 6G facing the upstream pressure chamber 13 of the valve 6, and the piston rod 7 (piston coupling portion) protrudes from the open pressure receiving surface 6G.

  According to the above configuration, the valve 6 is biased to the closing side via the piston rod 7 (piston coupling portion) by the piston 8 that receives the differential pressure between the pressure P1 of the upstream pressure chamber 13 and the external pressure, and therefore the upstream pressure P1. Is increased, the valve opening pressure at which the valve 6 opens the communication passages 3 and 4 is increased.

  [3] The differential pressure valve 1 has a configuration in which the cross-sectional area B of the piston 8 is larger than the cross-sectional area C of the piston rod 7 and smaller than the cross-sectional area A of the inner region of the portion that contacts the seat portion 9A of the valve 6. did.

  According to the above configuration, the valve 8 is biased to the open side by the pressure P1 of the upstream pressure chamber 13 because the cross-sectional area A of the portion that contacts the seat portion 9A of the valve 6 is larger than the cross-sectional area B of the piston 8. Since the cross-sectional area B of the piston 8 is larger than the cross-sectional area C of the piston rod 7, the piston 8 is urged to close the valve 6 by the pressure difference between the pressure P1 in the upstream pressure chamber 13 and the external pressure. As the pressure P1 in the side pressure chamber 13 increases, the differential pressure between the pressure P1 and the external pressure also increases, so that the differential pressure valve 1 is difficult to open.

  The differential pressure valve 1 includes a seal member 26 that is interposed between the housing 20 and the piston 8 and that is in sliding contact with the piston 8.

  According to the above configuration, in the differential pressure valve 1, the sliding contact portion of the piston 8 with respect to the cylinder portion 23 is sealed by the sealing member 26, and air (working fluid) is prevented from leaking from the upstream pressure chamber 13 to the outside.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the said 1st Embodiment, and description is abbreviate | omitted.

  In the differential pressure valve 1 according to the first embodiment, the seal member 26 is interposed between the housing 20 and the piston 8. In the differential pressure valve 101 according to the second embodiment, a configuration in which a membrane-like diaphragm 126 is interposed between the housing 120 and the piston 108 is different.

  The differential pressure valve 101 includes, as a valve opening pressure adjustment mechanism, a piston 108 that partitions the upstream pressure chamber 13 and the outside from which external pressure is guided, and a columnar piston rod 107 that connects the piston 108 to the valve 6.

  The housing 120 has a through hole 123 into which the piston 108 is inserted with a gap. The annular diaphragm 126 has an outer peripheral end fixed to the inner wall of the through hole 123, and an inner peripheral end fixed to the outer periphery of the piston 8, thereby sealing the gap between the through hole 123 and the piston 108. The diaphragm 126 is provided between the through hole 123 and the piston 108.

  The differential pressure valve 101 includes a downstream pressure P2 applied to the closing side pressure receiving surface 6F of the valve 6, a spring force of the spring 5, an upstream pressure P1 applied to the opening side pressure receiving surface 6G of the valve 6, and an upstream side applied to the piston 108. The valve 6 moves and opens and closes so that the pressure P1 is balanced.

  The diaphragm 126 is formed in a film shape by an elastic material such as a rubber material, and is elastically deformed following the movement of the piston 108 with respect to the through hole 123 so as not to restrain the movement of the piston 108.

  According to the above 2nd Embodiment, while exhibiting the effect of said [1]-[4] similarly to 1st Embodiment, there exists an effect shown below.

  [4] The differential pressure valve 101 includes a housing 120 that houses the piston 108 and a membrane-like diaphragm 126 that is interposed between the piston 108.

  According to the above configuration, the differential pressure valve 101 is sealed between the housing 120 and the piston 108 by the diaphragm 126, and air is prevented from leaking outside from the upstream pressure chamber 13. Since the diaphragm 126 does not have a portion that is in sliding contact with the piston 108 and the housing 120, the friction of the piston 108 can be suppressed.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the said 1st Embodiment, and description is abbreviate | omitted.

  In the differential pressure valve according to the first embodiment, a columnar piston rod 7 is provided as a piston connecting portion that connects the valve 6 and the piston 8. The differential pressure valve 201 according to the second embodiment is different in a configuration including a wire rope-like (cord-like) piston wire 207 as a piston connecting portion.

  The differential pressure valve 201 includes, as a valve opening pressure adjusting mechanism, a piston 208 that partitions the upstream pressure chamber 13 and the outside from which atmospheric pressure is guided, and a wire rope-shaped piston wire 207 that connects the piston 208 to the valve 6.

  The piston 208 is formed in a cylindrical shape separately from the valve 206 and is slidably inserted into the cylinder portion 23 of the housing 20. A seal member 26 is interposed between the cylinder portion 23 and the piston 8.

  One end of the wire rope-like piston wire 207 is coupled to the central portion of the opening-side pressure receiving surface 206G of the valve 206, and the other end is coupled to the central portion of the piston 208.

  The valve 206, the piston wire 207, and the piston 208 are arranged on the central axis O and are formed symmetrically with respect to the central axis O.

  The differential pressure valve 201 includes a downstream pressure P2 applied to the closed pressure receiving surface 206F of the valve 206, a spring force of the spring 5, an upstream pressure P1 applied to the open pressure receiving surface 206G of the valve 6, and an upstream applied to the piston 8. The valve 206 moves and opens and closes so that the pressure P1 is balanced. The piston wire 207 supports a tensile load in a direction in which the piston 208 moves away from the valve 206.

  According to the above 3rd Embodiment, while exhibiting the effect of said [1]-[4] similarly to 1st Embodiment, there exists an effect shown below.

  [5] The differential pressure valve 201 includes a wire rope-like piston wire 207 that connects the valve 206 and the piston 208 as a piston connecting portion.

  According to the above configuration, in the differential pressure valve 201, the piston wire 207 supports the tensile load in the direction in which the piston 208 is separated from the valve 206, and the piston 208 biases the valve 6 to the closed side. When the piston wire 207 is elastically deformed and bent in the radial direction of the piston 208, the concentricity required for the piston 208 and the cylinder part 23 is lowered, and the machining accuracy of the cylinder part 23 formed in the housing 20 is lowered. be able to.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The differential pressure valve of the present invention is not limited to a differential pressure valve unit mounted on a railway vehicle, and can be used for other machines, facilities, and the like.

DESCRIPTION OF SYMBOLS 1, 101, 201 Differential pressure valve 5 Spring 6, 206 Valve 6E Spring receiving part 6F Close side pressure receiving surface 6G Open side pressure receiving surface 7 Piston rod (piston coupling part)
8, 208 Piston 9A Seat portion 13 Upstream pressure chamber 14 Downstream pressure chamber 20 Housing 21, 22 Air spring 20, 120 Housing 126 Diaphragm 207 Piston wire (piston connecting portion)

Claims (5)

In the differential pressure valve that opens and closes according to the differential pressure between the upstream pressure and the downstream pressure of the working fluid,
An upstream pressure chamber into which the upstream pressure of the working fluid is guided;
A downstream pressure chamber into which the downstream pressure of the working fluid is guided;
A seat portion provided between the upstream pressure chamber and the downstream pressure chamber;
A valve that abuts against the seat portion and partitions the upstream pressure chamber and the downstream pressure chamber;
A piston that partitions the upstream pressure chamber and the outside from which external pressure is guided;
A piston connecting part for connecting the piston to the valve;
The differential pressure valve, wherein the piston urges the valve to close by a differential pressure between the upstream pressure and an external pressure. An open pressure receiving surface facing the upstream pressure chamber of the valve;
The differential pressure valve according to claim 1, wherein the piston connecting portion protrudes from the opening-side pressure receiving surface.   The cross-sectional area of the piston is larger than the cross-sectional area of the piston coupling portion and smaller than the cross-sectional area of the inner region of the portion that contacts the seat portion of the valve. The differential pressure valve described. A housing that houses the piston;
The differential pressure valve according to any one of claims 1 to 3, further comprising a membrane-like diaphragm interposed between the housing and the piston.   The differential pressure valve according to any one of claims 1 to 4, further comprising a cord-like piston wire connecting the valve and the piston as the piston connecting portion.

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