Leveling valve

Abstract

To provide a leveling valve capable of suppressing abrasion of a contact surface between a piston and a housing.SOLUTION: A leveling valve 100 includes a piston 20 stored in a storage hole 11 formed in a case 10 to move in an axial direction with the rotation of a lever 4, a stem 50 with one end inserted into a through-hole 22 formed in the piston 20 to move in an axial direction together with the piston 20, and a supply and exhaust valve 80 for communicating an air spring 3 with a compressor 7 by making the stem 50 move from a neutral position to one direction and communicating the air spring 3 with an exhaust passage 8 by making the stem 50 from the neutral position to the other direction. The piston 20 is fitted in the stem 50 to be movable in an axial direction and a radial direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a leveling valve.

Background Art

[0002] Patent Document 1 describes a leveling valve that supplies compressed air to the air spring of a railway vehicle or discharges air from the air spring to keep the support position of the railway vehicle by the air spring constant.

[0003] In the leveling valve described in Patent Document 1, when the load of the vehicle body changes and the support height of the vehicle body by the air spring changes, this change causes the lever to swing via a link, and the stem moves axially via a piston connected to the tip of the lever. Then, in response to the movement of this stem, the supply and discharge valve is opened and closed, and either the supply passage connected to the compressor or the exhaust passage released to the atmosphere is selectively connected to the air spring passage connected to the air spring.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the leveling valve described in Patent Document 1, the piston is fixed to the stem by a nut. Further, in the leveling valve described in Patent Document 1, a part of the stem is inserted into an insertion hole formed in the valve case, and the stem moves axially while being guided by this insertion hole.

[0006] When a piston is fixed to the stem by tightening a nut, as in the leveling valve described in Patent Document 1, the central axis of the stem and the central axis of the piston may be misaligned. When the stem and piston move axially with this misalignment, the piston may reciprocate in contact with the housing because the stem is guided by the insertion hole in the valve case. Repeated reciprocating motion with the piston in contact with the housing can cause wear on the contact surface between the piston and the housing, potentially reducing the reliability of the leveling valve.

[0007] This invention has been made in view of the above-mentioned problems, and aims to provide a leveling valve that can suppress wear on the contact surface between the piston and the housing. [Means for solving the problem]

[0008] The present invention relates to a leveling valve that adjusts the height of an air spring provided between a bogie and a car body by selectively connecting the air spring to a compressed air source or an exhaust passage according to the direction of rotation of a lever that rotates according to the relative displacement of the car body with respect to the bogie of a railway vehicle, the valve comprising a piston housed in a housing hole formed in the housing and moving in the axial direction of the housing hole as the lever rotates, before The piston is attached Penetrating in the axial direction Through hole One end Inserted through, together with the piston axis The system comprises a stem that moves in one direction, and a supply / exhaust valve that connects the air spring and the compressed air source when the stem moves in one direction from a neutral position, and connects the air spring and the exhaust passage when the stem moves in the other direction from the neutral position. The stem comprises a main body portion having a valve portion at its tip that constitutes part of the supply and discharge valve; an insertion portion having a smaller diameter than the main body portion and a smaller diameter than the through hole of the piston, and which passes through the through hole of the piston; a locking member provided at the tip of the insertion portion that passes through the through hole; and a first stage portion formed by the boundary between the main body portion and the insertion portion, which has a larger diameter than the through hole of the piston. The piston is, In a movable state between the first step and the locking member, It is characterized by being fitted onto the stem so as to be movable in the axial and radial directions.

[0009] In this invention, the piston is fitted to the stem so as to be movable in the axial and radial directions; in other words, the piston is not fixed to the stem. Therefore, even if the outer surface of the piston and the inner surface of the housing hole come into contact, the piston can move away from the contact point, thereby suppressing reciprocating motion while the outer surface of the piston is pressed against the inner surface of the housing hole. This suppresses wear on the contact surface between the piston and the housing. Furthermore, since the piston can be fitted into the stem in a manner that allows it to move in the axial and radial directions without adding any new parts, cost increases can be suppressed.

[0012] Furthermore, the present invention further comprises a stem formed at the end of the insertion portion opposite to the main body portion, having a smaller diameter portion smaller in diameter than the insertion portion, a male thread portion formed on the outer circumferential surface of the smaller diameter portion to which a nut is fastened, and a second stage portion formed by the boundary portion between the insertion portion and the smaller diameter portion, wherein the locking member is a washer through which the smaller diameter portion is inserted and which has a larger diameter than the through hole of the piston, the washer is fixed between the nut and the second stage portion by fastening the nut to the male thread portion, and the length between the first stage portion and the second stage portion is longer than the axial length of the through hole of the piston.

[0013] In this invention, the locking member is positioned axially by a nut and a second stage. This allows for precise setting of the allowable axial movement of the piston. [Effects of the Invention]

[0014] According to the present invention, a leveling valve can be provided that can suppress wear on the contact surface between the piston and the housing. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a mounting diagram of a leveling valve according to an embodiment of the present invention. [Figure 2] Figure 2 is an axial cross-sectional view of a leveling valve according to an embodiment of the present invention. [Figure 3] Figure 3 is a radial cross-sectional view of a leveling valve according to an embodiment of the present invention. [Figure 4]FIG. 4 is an enlarged view of the vicinity of the piston in the leveling valve according to an embodiment of the present invention. [Figure 5] FIG. 5 is an enlarged view of the vicinity of the supply / discharge valve in the leveling valve according to an embodiment of the present invention. MODE FOR CARRYING OUT THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0017] The leveling valve 100 according to an embodiment of the present invention will be described. First, the outline of the leveling valve 100 will be described with reference to FIGS. 1 and 2.

[0018] The leveling valve 100 has a function of adjusting the height of the air spring 3 provided between the car body 1 and the bogie 2 of a railway vehicle to maintain the car body 1 at a constant height.

[0019] As shown in FIG. 1, the leveling valve 100 is mounted across between the car body 1 and the bogie 2. Specifically, the leveling valve 100 is attached to the car body 1 and connected to the bogie 2 via a lever 4 and a connecting rod 5. When the air spring 3 expands and contracts due to a change in the load of the car body 1 and the height of the car body 1 changes, this change is transmitted to the leveling valve 100 via the connecting rod 5 and the lever 4.

[0020] When the car body load increases and the air spring 3 deflects, the lever 4 is pushed upward from the neutral position (rotation in the direction of arrow A in FIG. 1), and accordingly, the piston 20 (see FIG. 2) of the leveling valve 100 moves, whereby an air supply valve 80A described later opens, and an air spring passage 6 communicating with the air spring 3 and a supply passage 9 communicating with a compressor 7 as a compressed air source are communicated. Thereby, compressed air from the compressor 7 is supplied to the air spring 3. When the air spring 3 returns to a certain height, the lever 4 returns to the neutral position and the air supply valve 80A of the leveling valve 100 closes, shutting off the supply of compressed air.

[0021] On the other hand, when the vehicle body load decreases and the air spring 3 extends, the lever 4 is pulled downward from the neutral position (rotates in the direction of arrow B in FIG. 1), and accordingly, an exhaust valve 80B of the leveling valve 100 described later opens, and the air spring passage 6 and the exhaust passage 8 communicate with each other. Since the exhaust passage 8 communicates with the atmosphere, the compressed air in the air spring 3 is discharged to the atmosphere. When the air spring 3 returns to a certain height, the lever 4 returns to the neutral position and the exhaust valve 80B of the leveling valve 100 closes, blocking the discharge of the compressed air.

[0022] In this way, the leveling valve 100 selectively communicates the air spring 3 with the compressor 7 or the exhaust passage 8 according to the rotation direction of the lever 4 that rotates according to the relative displacement of the vehicle body 1 with respect to the bogie 2, automatically adjusting the relative displacement generated between the vehicle body 1 and the bogie 2 to maintain the vehicle body 1 at a constant height.

[0023] Next, referring to FIGS. 2 and 3, the specific configuration of the leveling valve 100 will be described. FIG. 2 is an axial cross-sectional view of the leveling valve 100, and FIG. 3 is a radial cross-sectional view of the leveling valve 100. In addition, the "axial direction" of the present embodiment means the direction of the central axis in the piston 20 and the stem 50, and the "radial direction" means the radial direction in the piston 20 and the stem 50.

[0024] The leveling valve 100 includes a case 10 having a housing hole 11 formed to penetrate the inside and fixed to the vehicle body 1, a first cap member 12 attached to one side surface of the case 10 and closing one opening of the housing hole 11, a second cap member 13 attached to the other side surface of the case 10, and a cylindrical valve case 40 closing the other opening of the housing hole 11.

[0025] The first cap member 12 comprises a cylindrical insertion portion 12a that is inserted into the housing hole 11, and a flange portion 12b that is formed continuously with the insertion portion 12a and has a larger diameter than the insertion portion 12a. The first cap member 12 is attached to the case 10 by fastening a bolt (not shown) through a through hole (not shown) provided in the flange portion 12b to a bolt hole formed in the case 10.

[0026] A male threaded portion 40b is formed on a part of the outer circumferential surface of the valve case 40. The valve case 40 comprises a first cylindrical portion 40a and a second cylindrical portion 40c, separated by the male threaded portion 40b. The first cylindrical portion 40a and the male threaded portion 40b are inserted into the housing hole 11. The male threaded portion 40b is screwed into a female threaded portion 11a formed near the opening of the housing hole 11. In this way, the valve case 40 is fixed to the case 10.

[0027] The second cap member 13 is fixed to the case 10 so as to cover the outer circumferential surface of the second cylindrical portion 40c of the valve case 40 and the side of the male thread portion 40b on the second cylindrical portion 40c side. This prevents the valve case 40 from coming off the case 10. The second cap member 13 has a flow path 13a that connects the flow path 10b formed in the case 10 and the through hole 46 that connects the inside and outside of the valve case 40.

[0028] As shown in Figure 3, the case 10 has a recess 16 that opens radially to the housing hole 11. The recess 16 is formed to connect with the housing hole 11.

[0029] The leveling valve 100 further includes a cover member 70 that covers the recess 16 and is attached to the case 10. When the cover member 70 is attached to the case 10, a housing space 17 is formed for housing the rotor 30, which will be described later.

[0030] The cover member 70 has a communication hole 72 that connects the containment space 17 to the outside. A filter 73 is provided in the communication hole 72 to prevent foreign matter from entering from the outside.

[0031] In the leveling valve 100, the housing is composed of a case 10, a first cap member 12, a second cap member 13, a cover member 70, and a valve case 40.

[0032] As shown in Figures 2 and 3, the leveling valve 100 further comprises a piston 20 housed in a housing hole 11 of the case 10 and moving axially with the rotation of the lever 4, a rotor 30 for transmitting the rotation of the lever 4 to the piston 20, a stem 50 with one end inserted through a through hole 22 formed in the piston 20 and moving axially together with the piston 20, and a supply / exhaust valve 80 which connects the air spring 3 and the compressor 7 when the stem 50 moves in one direction from the neutral position, and connects the air spring 3 and the exhaust passage 8 when the stem 50 moves in the other direction from the neutral position.

[0033] The piston 20 is movably supported by the stem 50 within the housing hole 11 of the case 10. A small gap is provided between the outer surface of the piston 20 and the inner surface of the housing hole 11. As a result, the outer surface of the piston 20 does not slide against the inner surface of the housing hole 11, and therefore no frictional resistance is generated. A groove 21 with a crescent cross-sectional shape is formed on a part of the outer surface of the piston 20, as shown in Figure 3.

[0034] As shown in Figure 3, the rotor 30 is rotatably supported in a support hole 71 formed in the cover member 70 via bearings 14 and 15. The rotor 30 has a cylindrical body portion 31 supported by the bearings 14 and 15, a rectangular prism-shaped boss portion 32 formed to protrude from one end of the body portion 31 and having a two-sided width smaller than the outer diameter of the body portion 31, a flange portion 33 provided at the other end of the body portion 31, and an arm portion 34 formed to protrude radially outward from the outer circumferential surface of the flange portion 33. The boss portion 32 is fitted into a fitting hole 4a formed in the lever 4 (see Figure 1). As shown in Figures 2 and 3, a pin 35 is press-fitted into the arm portion 34. The pin 35 is inserted into a sleeve 36 and is movably inserted together with the sleeve 36 into a groove 21 of the piston 20. As a result, when the boss portion 32 rotates with the rotation of the lever 4, the pin 35 press-fitted into the arm portion 34 rotates in the direction of the arrow shown in Figure 2. Since the pin 35 is inserted into the groove 21 of the piston 20, the piston 20 moves axially within the housing hole 11 as the pin 35 rotates.

[0035] As shown in Figure 2, the stem 50 is formed in a rod shape that extends in the direction of movement of the piston 20 (axial direction of the housing hole 11). As shown in Figures 2 and 4, the stem 50 has a main body portion 50A with a valve portion 53 at its tip that constitutes part of the supply and discharge valve 80; an insertion portion 50B that is smaller in diameter than the main body portion 50A and smaller in diameter than the through hole 22 of the piston 20 and passes through the through hole 22 formed in the piston 20; a stepped portion 50C as a first step portion that is larger in diameter than the through hole 22 of the piston 20 and is formed by the boundary portion between the main body portion 50A and the insertion portion 50B; a small diameter portion 50D formed at the end of the insertion portion 50B opposite to the main body portion 50A and smaller in diameter than the insertion portion 50B; a male thread portion 50E formed on the outer circumferential surface of the small diameter portion 50D and to which a nut 60 is fastened; and a stepped portion 50F as a second step portion that is formed by the boundary portion between the insertion portion 50B and the small diameter portion 50D.

[0036] As shown in Figures 2 and 4, the main body portion 50A of the stem 50 is provided with an axially extending axial hole 51. On the insertion portion 50B side of the main body portion 50A, multiple through holes 52 are provided radially, connecting the axial hole 51 and the housing hole 11. The axial hole 51 communicates with the outside through the through holes 52, the housing hole 11, the housing space 17, and the communication holes 72. The axial hole 51, through holes 52, housing hole 11, housing space 17, and communication holes 72 constitute the exhaust passage 8.

[0037] As shown in Figure 2, an annular groove 54 is formed on the outer circumferential surface of the main body portion 50A of the stem 50. A valve portion 53 is formed adjacent to the annular groove 54 on the tip side of the stem 50, with a smaller diameter than the piston 20 side of the stem 50 and a larger diameter than the annular groove 54. The valve portion 53 will be described in detail later.

[0038] The stem 50 is connected to the piston 20 by inserting the insertion portion 50B through the through hole 22 formed in the piston 20 and fastening the nut 60 to the male thread portion 50E. Also, as shown in Figures 2 and 4, a washer 61 is provided between the insertion portion 50B and the nut 60, with an outer diameter larger than the inner diameter of the through hole 22 in the piston 20 and inserted through the small diameter portion 50D. The washer 61 is fixed between the nut 60 and the stepped portion 50F (see Figure 4) by fastening the nut 60 to the male thread portion 50E. The washer 61 functions as a locking member that prevents the piston 20 from falling out of the stem 50.

[0039] The leveling valve 100 further comprises an annular ring member 81 positioned opposite the outer circumference of the tip of the stem 50 and movable in the radial direction. The ring member 81 has a valve seat portion 81a formed on one end face and is positioned inside the valve case 40.

[0040] Now, with reference to Figures 2 and 5, the valve case 40 and the internal structure of the valve case 40 will be described.

[0041] The valve case 40 includes a first through hole 41 into which the tip of the stem 50 is inserted, a second through hole 42 formed to be larger in diameter than the first through hole 41, and a stepped portion 43 that forms the boundary between the first through hole 41 and the second through hole 42.

[0042] An O-ring 44 is provided near the tip of the first through-hole 41 on the piston 20 side, to seal the space between the inner surface of the first through-hole 41 and the outer surface of the stem 50.

[0043] A ring member 81, a cylindrical collar member 86 having an internal space 86a, and a plug 84 that closes the opening of the second through hole 42 are provided inside the second through hole 42. The plug 84 is locked by a retaining ring 87 engaged inside the second through hole 42, by pressing the ring member 81 against the stepped portion 43 via the collar member 86.

[0044] The internal space 86a of the color member 86 is provided with a valve body 82 that seats away from the valve seat portion 81a of the ring member 81, a spring 83 that biases the valve body 82 toward the valve seat portion 81a, and a check valve body 85 that seats away from the valve seat portion 84a formed on the plug 84 and is biased toward the valve seat portion 84a by the spring 83.

[0045] A gap is provided between the outer circumferential surface of the ring member 81 and the inner circumferential surface of the second through hole 42, and an O-ring 90 is provided to prevent compressed air from leaking through the gap. Since the O-ring 90 is elastic, the ring member 81 can move radially within the second through hole 42.

[0046] As shown in Figure 5, the ring member 81 includes a valve seat portion 81a formed on one end face and an annular projection portion 81b formed to project radially inward from the inner circumferential surface on one end. At the tip of the stem 50, a small annular gap S is formed by the gap between the inner circumferential surface of the projection portion 81b and the outer circumferential surface of the valve portion 53 of the stem 50, which restricts the flow of compressed air when the supply and discharge valve 80 is opened and closed (see Figure 5). The annular gap S communicates with the air spring 3 through an annular groove 54, a through hole 45 formed in the valve case 40, a passage 10a formed in the case 10, an annular flow path 10c formed between the inner circumferential surface of the case 10 and the insertion portion 12a of the first cap member 12, and a through flow path 10d formed in the case 10 and connected to the annular flow path 10c. The annular gap S, the annular groove 54, the through hole 45, the passage 10a, the annular flow path 10c, and the through flow path 10d constitute the air spring passage 6.

[0047] As shown in Figure 2, a flow path 84b is formed inside the plug 84. The flow path 84b communicates with the compressor 7 through the through hole 46 in the valve case 40, the flow path 13a in the second cap member 13, and the flow path 10b in the case 10.

[0048] The check valve body 85 seats to and from the valve seat portion 84a of the plug 84. When the pressure on the compressor 7 side (flow path 84b) is higher than the pressure downstream of the check valve body 85 (internal space 86a), the check valve body 85 separates from the valve seat portion 84a against the biasing force of the spring 83. Conversely, when the pressure on the compressor 7 side (flow path 84b) is lower than the pressure downstream of the check valve body 85 (internal space 86a), the check valve body 85 seats to the valve seat portion 84a. In the leveling valve 100, the supply passage 9 is formed by the internal space 86a, the flow path 84b, the through hole 46, the flow path 13a, and the flow path 10b.

[0049] The valve case 40 includes an internal supply and exhaust valve 80. The supply and exhaust valve 80 includes an air supply valve 80A that controls communication or blocking between the supply passage 9 and the air spring passage 6, and an exhaust valve 80B that controls communication or blocking between the air spring passage 6 and the exhaust passage 8. A detailed explanation follows below.

[0050] The valve body 82 has an elastic seat portion 82a. The seat portion 82a seats onto and away from the valve seat portion 81a of the ring member 81. When the seat portion 82a of the valve body 82 seats onto the valve seat portion 81a of the ring member 81, communication between the supply passage 9 and the air spring passage 6 is blocked. Conversely, when the seat portion 82a of the valve body 82 separates from the valve seat portion 81a of the ring member 81, communication between the supply passage 9 and the air spring passage 6 is restored. In this way, the seat portion 82a of the valve body 82 and the valve seat portion 81a of the ring member 81 constitute the air supply valve 80A that controls the supply of air to the air spring 3.

[0051] The valve portion 53 of the stem 50 seats onto and away from the seat portion 82a of the valve body 82. When the valve portion 53 of the stem 50 seats onto the seat portion 82a of the valve body 82, communication between the air spring passage 6 and the exhaust passage 8 is blocked. Conversely, when the valve portion 53 of the stem 50 separates from the seat portion 82a of the valve body 82, communication between the air spring passage 6 and the exhaust passage 8 is restored. In this way, the valve portion 53 of the stem 50 and the seat portion 82a of the valve body 82 constitute the exhaust valve 80B that controls the exhaust from the air spring 3.

[0052] The operation of the leveling valve 100 configured as described above will now be explained.

[0053] As described above, when the vehicle load increases and the air spring 3 flexes, the lever 4 is pushed upward from its neutral position (rotation in the direction of arrow A in Figure 1). Consequently, the rotor 30 connected to the lever 4 rotates to the right in Figure 2, causing the pin 35 provided on the arm portion 34 of the rotor 30 to rotate to the right around the main body portion 31. The pin 35 rotates to the right while moving downward in Figure 2 within the groove 21 of the piston 20. As a result, the piston 20 moves to the right in Figure 2. Consequently, the stem 50 connected to the piston 20 pushes the valve body 82 against the biasing force of the spring 83, separating it from the valve seat portion 81a of the ring member 81. This connects the supply passage 9 and the air spring passage 6. Specifically, the compressed air discharged from the compressor 7 is supplied to the air spring 3 through the path of flow path 10b, flow path 13a, through hole 46, flow path 84b, internal space 86a, annular gap S, annular groove 54, through hole 45, passage 10a, annular flow path 10c, and through flow path 10d.

[0054] At this time, the valve portion 53 of the stem 50 is pressed against the seat portion 82a of the valve body 82, so that the axial hole 51 and the annular gap S are kept closed. In other words, when the piston 20 moves to the right from the neutral position, the intake valve 80A opens, allowing the supply passage 9 and the air spring passage 6 to communicate, and the exhaust valve 80B closes, blocking the exhaust passage 8 and the air spring passage 6.

[0055] When the supply passage 9 and the air spring passage 6 are connected, compressed air from the compressor 7 is supplied to the air spring 3 through the supply passage 9 and the air spring passage 6, causing the height of the air spring 3 to increase. Consequently, the height of the vehicle body 1 increases, and the lever 4 moves closer to the neutral position. As the lever 4 approaches the neutral position, the piston 20 and stem 50 also move to the left in Figure 1. Eventually, when the height of the vehicle body 1 returns to the specified position, the lever 4 returns to the neutral position, and the seat portion 82a of the valve body 82 seats on the valve seat portion 81a of the ring member 81. In other words, the air intake valve 80A of the leveling valve 100 closes. This blocks the connection between the supply passage 9 and the air spring passage 6, and the supply of compressed air to the air spring 3 is cut off.

[0056] Conversely, when the vehicle load decreases and the air spring 3 extends, the lever 4 is pushed downward from the neutral position (rotation in the direction of arrow B in Figure 1). As a result, the rotor 30 connected to the lever 4 rotates to the left in Figure 2, causing the pin 35 provided on the arm portion 34 of the rotor 30 to rotate to the left around the main body portion 31. The pin 35 rotates to the left while moving downward in Figure 2 within the groove 21 of the piston 20. As a result, the piston 20 moves to the left in Figure 2. The stem 50 moves to the left along with the piston 20. Consequently, the valve portion 53 of the stem 50 separates from the seat portion 82a of the valve body 82. This connects the air spring passage 6 and the exhaust passage 8. Specifically, the compressed air inside the air spring 3 is released into the atmosphere through the passage 10d, the annular passage 10c, the passage 10a, the through hole 45, the annular groove 54, the annular gap S, the axial hole 51, the through hole 52, the containment hole 11, the containment space 17, and the communication hole 72.

[0057] At this time, the seat portion 82a of the valve body 82 is pressed against the valve seat portion 81a of the ring member 81 by the biasing force of the spring 83, so that the internal space 86a of the collar member 86 and the annular gap S are blocked off. In other words, when the piston 20 moves to the left from the neutral position, the exhaust valve 80B opens and the air spring passage 6 and the exhaust passage 8 come into contact, and the intake valve 80A closes and the supply passage 9 and the air spring passage 6 are blocked off.

[0058] When the air spring passage 6 and the exhaust passage 8 are connected, compressed air from the air spring 3 is released into the atmosphere through the air spring passage 6 and the exhaust passage 8, causing the height of the air spring 3 to decrease. Consequently, the height of the vehicle body 1 decreases, and the lever 4 moves closer to the neutral position. As the lever 4 approaches the neutral position, the piston 20 and stem 50 also move to the right in Figure 1. Eventually, when the height of the vehicle body 1 returns to the specified position, the lever 4 returns to the neutral position, and the valve portion 53 of the stem 50 seats on the seat portion 82a of the valve body 82. In other words, the exhaust valve 80B of the leveling valve 100 closes. As a result, the connection between the air spring passage 6 and the exhaust passage 8 is blocked, and the exhaust of compressed air from the air spring 3 is blocked.

[0059] In this way, the leveling valve 100 adjusts the height of the air spring 3 by selectively connecting it to the compressor 7 or the atmosphere, according to the direction of rotation of the lever 4, which rotates in accordance with the relative displacement of the car body 1 with respect to the bogie 2.

[0060] Next, we will explain the function of the annular gap S.

[0061] For example, when a railway vehicle is in motion, the height of the vehicle body 1 changes in small increments due to vibrations and other factors. If the height of the air spring 3 changes in small increments accordingly, the ride comfort will deteriorate. For this reason, the leveling valve 100 is provided with an annular gap S. As a result, when the amount of change in the height of the vehicle body 1 is small, that is, when the amount of change of the stem 50 is small, even if the intake valve 80A or exhaust valve 80B is opened, the flow rate supplied to the air spring passage 6 or the flow rate discharged from the air spring passage 6 is limited because the annular gap S exists. This prevents the height of the air spring 3 from following the small increments in the height of the vehicle body 1. This prevents the ride comfort from deteriorating. Even with the annular gap S provided, when the stem 50 moves to a position where the valve portion 53 and the projection portion 81b are misaligned in the axial direction, the annular gap S disappears, and a large flow rate of compressed air can be passed through.

[0062] By the way, in the leveling valve 100, for example, when the piston 20 is fixed to the stem 50 by tightening the nut 60, the central axes of the piston 20 and the stem 50 may be misaligned when they are fixed. When the piston 20 and the stem 50 move axially with their central axes misaligned in this way, the stem 50 is guided by the first through hole 41 formed in the valve case 40, so there is a risk that the piston 20 will reciprocate while in contact with the housing hole 11 of the case 10. When the piston 20 reciprocates while in contact with the housing hole 11 of the case 10 in this way, the contact surface between the piston 20 and the housing hole 11 of the case 10 will wear down.

[0063] Therefore, in the leveling valve 100 of this embodiment, the piston 20 is connected to the stem 50 with some play. In other words, the piston 20 is fitted to the stem 50 so as to be movable in the axial and radial directions. Now, with reference to Figure 4, the connection structure between the piston 20 and the stem 50 will be described in detail.

[0064] As shown in Figure 4, the axial length L1 of the wall portion 23 in which the through hole 22 of the piston 20 is formed is shorter than the axial length L2 between the stepped portion 50C and the stepped portion 50F (washer 61) of the stem 50. As a result, there is an axial gap S1 of L2-L1 between the wall portion 23 of the piston 20 and the stepped portions 50C and 50F (washer 61) of the stem 50, so the piston 20 is allowed to move by this gap S1 in the axial direction.

[0065] Furthermore, as shown in Figure 4, the inner diameter D1 of the through hole 22 of the piston 20 is larger than the outer diameter D2 of the insertion portion 50B of the stem 50. Since there is an axial gap S2 between the through hole 22 of the piston 20 and the insertion portion 50B of the stem 50, the piston 20 is allowed to move radially by the amount of this gap S2.

[0066] Thus, in the leveling valve 100 of this embodiment, the piston 20 is allowed to move axially and radially relative to the stem 50 by a gap S1, S2. In other words, in the leveling valve 100, the piston 20 and the stem 50 are not fixed in a misaligned state. Therefore, even if the outer surface of the piston 20 and the inner surface of the housing hole 11 of the case 10 come into contact, the piston 20 can move away from the contact point, that is, the piston 20 can move away from the contact point. This suppresses reciprocating motion of the outer surface of the piston 20 while it is pressed against the inner surface of the housing hole 11, thereby suppressing wear on the contact surface of the piston 20 with the case 10.

[0067] In the above embodiment, the case in which the piston 20 is connected to the stem 50 using a nut 60 and a washer 61 was described as an example, but the invention is not limited to this, and for example, the piston 20 may be connected to the stem 50 with a configuration in which the nut 60 and washer 61 are integrated (a so-called flanged nut). Alternatively, the piston 20 may be connected to the stem 50 using only the nut 60 without providing the washer 61.

[0068] Furthermore, instead of using a nut 60 and washer 61, the piston 20 may be connected to the stem 50 by attaching a cotter pin or press-fit pin to the stem 50.

[0069] According to the above embodiments, the following effects are achieved.

[0070] In the leveling valve 100, the piston 20 is fitted to the stem 50 so as to be movable in the axial and radial directions. Therefore, even if the outer surface of the piston 20 and the inner surface of the housing hole 11 of the case 10 come into contact, the piston 20 can move away from the contact point, that is, in a direction away from the contact point. This prevents the outer surface of the piston 20 from reciprocating while pressed against the inner surface of the housing hole 11. Thus, wear on the contact surface of the piston 20 with the case 10 can be suppressed, improving the durability and reliability of both the piston 20 and the case 10.

[0071] Furthermore, with the leveling valve 100, the amount of axial play between the piston 20 and the stem 50 can be easily adjusted by adjusting the position of the stepped portion 50F. Similarly, the amount of radial play (gap S1, S2) between the piston 20 and the stem 50 can be easily adjusted by adjusting the inner diameter of the through hole 22 of the piston 20 or the outer diameter of the insertion portion 50B of the stem 50.

[0072] The configuration, operation, and effects of the embodiment of the present invention configured as described above will be summarized below.

[0073] The leveling valve 100 adjusts the height of the air spring 3, which is installed between the bogie 2 and the car body 1, by selectively connecting it to a compressed air source (compressor 7) or an exhaust passage 8, according to the direction of rotation of a lever 4 that rotates in accordance with the relative displacement of the car body 1 with respect to the bogie 2 of the railway vehicle. The leveling valve 100 also includes a piston 20 housed in a housing hole 11 formed in the housing (case 10) and moving axially with the rotation of the lever 4, a stem 50 with one end inserted through a through hole 22 formed in the piston 20 and moving axially together with the piston 20, and a supply / exhaust valve 80 which connects the air spring 3 to the compressed air source (compressor 7) when the stem 50 moves in one direction from the neutral position, and connects the air spring 3 to the exhaust passage 8 when the stem 50 moves in the other direction from the neutral position, and the piston 20 is fitted into the stem 50 so as to be movable in the axial and radial directions.

[0074] In this configuration, the piston 20 is fitted to the stem 50 so as to be movable in the axial and radial directions. In other words, since the piston 20 is not fixed to the stem 50, even if the outer surface of the piston 20 and the inner surface of the housing hole 11 come into contact, the piston 20 can move away from the contact point. This prevents the outer surface of the piston 20 from reciprocating while pressed against the inner surface of the housing hole 11. This reduces wear on the contact surface between the piston 20 and the housing (case 10). Therefore, the durability and reliability of the piston 20 and the case 10 can be improved.

[0075] In the leveling valve 100, the stem 50 has a main body portion 50A with a valve portion 53 at its tip that forms part of the supply and discharge valve 80, an insertion portion 50B which is smaller in diameter than the main body portion 50A and smaller in diameter than the through hole 22 of the piston 20 and through the through hole 22 of the piston 20, and a stepped portion 50C (first stepped portion) which is formed by the boundary portion between the main body portion 50A and the insertion portion 50B and is larger in diameter than the through hole 22 of the piston 20, and the piston 20 is movable between the stepped portion 50C (first stepped portion) and a washer 61 (locking member) fixed to the insertion portion 50B.

[0076] In this configuration, the piston 20 can be fitted to the stem 50 so as to be movable in the axial and radial directions without adding any new parts compared to the conventional configuration, thus suppressing an increase in costs.

[0077] In the leveling valve 100, the stem 50 further has a small-diameter portion 50D formed to be smaller in diameter than the insertion portion 50B at the end of the insertion portion 50B opposite to the main body portion 50A, a male thread portion 50E formed on the outer circumferential surface of the tip side of the small-diameter portion 50D to which a nut 60 is fastened, and a stepped portion 50F (second stepped portion) formed by the boundary portion between the insertion portion 50B and the small-diameter portion 50D. The locking member is a washer 61 through which the small-diameter portion 50D is inserted and which has a larger diameter than the inner diameter of the through hole 22 of the piston 20. The washer 61 is fixed between the nut 60 and the stepped portion 50F (second stepped portion) by fastening the nut 60 to the male thread portion 50E, and the length between the stepped portion 50C (first stepped portion) and the stepped portion 50F (second stepped portion) is longer than the axial length of the through hole 22 of the piston 20.

[0078] In this configuration, the washer 61 (locking member) is positioned axially by the nut 60 and the stepped portion 50F (second stepped portion). This allows for precise setting of the axial play (allowable movement) of the piston 20.

[0079] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of Symbols]

[0080] 100... Leveling valve, 1... Body, 2... Bogie, 3... Air spring, 4... Lever, 6... Air spring passage, 7... Compressor (compressed air source), 8... Exhaust passage, 9... Supply passage, 10... Case (housing), 11... Housing hole, 12... First cap member (housing), 12c... Guide hole, 13... Second cap member (housing), 20... Piston 21... Groove, 30... Rotor, 35... Pin, 40... Valve case (housing), 50... Stem, 50A... Main body, 50B... Insertion part, 50C... Stepped section (first step), 50D... Small diameter section, 50E... Male thread section, 50F... Stepped section (second step), 53... Valve section, 60... Nut, 61... Washer, 80... Intake / exhaust valve, 80A... Intake valve, 80B... Exhaust valve

Claims

1. A leveling valve that adjusts the height of an air spring provided between a bogie and a car body by selectively connecting the air spring to a compressed air source or an exhaust passage according to the direction of rotation of a lever that rotates according to the relative displacement of the car body with respect to the bogie of a railway vehicle, A piston housed in a housing formed in the housing and moving axially in the housing as the lever rotates, A stem, one end of which is inserted through an axially penetrating through-hole formed in the piston, moves axially together with the piston, The system includes a supply and exhaust valve, the stem of which moves in one direction from a neutral position to connect the air spring and the compressed air source, and the stem of which moves in another direction from a neutral position to connect the air spring and the exhaust passage, The aforementioned stem is, A main body portion having a valve portion at its tip that constitutes part of the aforementioned supply and discharge valve, An insertion portion is formed to have a smaller diameter than the main body and a smaller diameter than the through hole of the piston, and to pass through the through hole of the piston, A locking member provided at the tip of the insertion portion that penetrates the through hole, It has a first stage portion formed by the boundary between the main body portion and the insertion portion, and having a larger diameter than the through hole of the piston, The leveling valve is characterized in that the piston is fitted to the stem so as to be movable in the axial and radial directions, while being movable between the first stage and the locking member.

2. A leveling valve according to claim 1, The aforementioned stem is, A small-diameter portion is formed at the end of the insertion portion opposite to the main body portion, and has a smaller diameter than the insertion portion. A male threaded portion formed on the outer circumferential surface of the small diameter portion, to which a nut is fastened, It further comprises a second stepped portion formed by the boundary between the insertion portion and the small diameter portion, The locking member is a washer through which the small diameter portion is inserted and which has a larger diameter than the inner diameter of the through hole of the piston. The washer is fixed between the nut and the second stage by fastening the nut to the male thread portion. A leveling valve characterized in that the length between the first stage and the second stage is longer than the axial length of the through hole of the piston.

Images