JP5324502B2 - Damping valve - Google Patents

Description

  The present invention relates to an improved damping valve.

  Conventionally, in this type of damping valve, for example, an annular valve is provided in the middle of a passage communicating two pressure chambers provided inside a shock absorber interposed between a bogie and a vehicle body of a railway vehicle. A piston having a valve hole with a seat; a valve body that can be freely attached to and detached from the annular valve seat; and that is accommodated in the valve hole; a spring seat stacked on the piston; and the valve body and the spring seat. There are known ones that are configured to include a coil spring that is interposed and biases the valve body toward the annular valve seat (see, for example, Patent Document 1).

  When the pressure valve receives pressure from the spring seat side against the valve hole, the valve body sits on the annular valve seat and closes the valve hole. Conversely, when pressure is received from the annular valve seat side, the valve body The valve is retreated from the annular valve seat to open the valve hole and allow fluid flow. More specifically, when the shock absorber operates, if the annular valve seat side of the valve hole faces the pressure chamber reduced by the piston, the valve body is pushed into the valve hole by the pressure in the pressure chamber that rises. It is designed to open the valve. When the damping valve is opened, the fluid that has entered the valve hole moves into the pressure chamber on the expansion side via a communication groove provided in the piston.

  In addition, as the pressure in the reduction-side pressure chamber increases, the retraction amount of the valve body retreating in the direction away from the annular valve seat increases, and the valve opening area limited by the valve body and the annular valve seat increases as the retraction amount increases. However, when the valve body is retracted from the annular valve seat by a predetermined amount of retraction, the valve opening area limited by the valve body and the annular valve seat becomes larger than the flow passage area in the communication groove, and the valve body beyond that The flow path area does not change with respect to the backward movement.

  Furthermore, the spring seat is not stacked on the piston, but is screwed into a valve hole provided in the piston (see, for example, Patent Document 2). When the annular valve seat side of the valve hole faces the pressure chamber on the reduction side, the valve body is opened by being pushed into the valve hole by the pressure in the pressure chamber that rises, and the pressure in the pressure chamber on the reduction side As the valve body moves upward, the retraction amount of the valve body retreating in the direction away from the annular valve seat increases, and as the retraction amount increases, the valve opening area limited by the valve body and the annular valve seat increases. When the retracted amount is retracted from the annular valve seat, the valve opening area limited by the valve body and the annular valve seat becomes greater than the flow passage area in the through hole provided in the spring seat, and the valve body is further retracted. On the other hand, the flow path area does not change

  Further, the shock absorber provided with the damping valve includes a constant orifice arranged in parallel with the damping valve. Such a shock absorber has a relatively abrupt square characteristic due to a constant orifice when the expansion / contraction speed is extremely low, such as the damping force characteristic (damping force characteristic) shown in FIG. The damping valve opens when the expansion speed exceeds the low speed range and becomes the high speed area, and the valve opening area expands as the expansion speed increases. If the damping force with a small dynamic damping coefficient is output, and the flow path area does not increase even when the expansion and contraction speed is extremely high and the valve body is retracted, the damping force with a relatively large damping coefficient will be exhibited. Will do.

JP 2007-71233 A JP 2007-71232 A

  By the way, in particular, in a shock absorber provided for the purpose of suppressing lateral vibrations of a bogie and a vehicle body in a railway vehicle, mainly vehicle body vibrations caused by an input of disturbance in a track error, a cross wind, a tunnel traveling, etc. In recent years, there has been a demand for suppression for the purpose of improving riding comfort. However, in recent years, when the vehicle body vibrates due to a strong earthquake or the like generated while the vehicle is running, the vehicle body vibration is effectively exerted with a large damping force. It has come to be required to suppress.

  When this requirement is achieved with a conventional shock absorber, the damping force characteristics after the shock absorber expansion and contraction speed exceeds the high speed region and reaches the ultra high speed region, and the flow path area does not increase even if the valve body is retracted. Therefore, it is only necessary to tune to a characteristic capable of suppressing vehicle body vibration when a strong earthquake occurs.

  However, if the damping force characteristic is tuned mainly for the suppression of vehicle body vibration when a strong earthquake occurs, the damping force that should be generated when the expansion and contraction speed of the shock absorber is in the ultra high speed region must be very large. As a result, the damping force generated when the expansion / contraction speed of the shock absorber is in an area where it does not reach ultra high speed is also increased by this, so it is attenuated during normal driving (hereinafter simply referred to as “normal driving”) that is not during an earthquake. As a result, the ride is overpowered and the ride comfort of the vehicle is impaired.

  On the other hand, if the damping force during normal driving is set so as not to impair the riding comfort of the vehicle, this time, the damping force that should be generated when the expansion and contraction speed of the shock absorber is in the ultra high speed region is too small. There is a risk that vehicle body vibration during a strong earthquake cannot be effectively suppressed.

  In other words, there is a trade-off between the ride comfort during normal driving and the effective suppression of vehicle vibration during strong earthquakes. With conventional damping valves, the ride comfort during normal driving and vehicle vibration during strong earthquakes occur. It has been difficult to achieve both effective suppression.

  Therefore, the present invention was devised to improve the above-described problems, and the object of the present invention is to effectively suppress the ride comfort during normal driving of a railway vehicle and vehicle body vibration when a strong earthquake occurs. It is an object of the present invention to provide a damping valve capable of achieving both of the above.

  In order to solve the above-described object, the problem-solving means in the present invention is configured to connect one chamber and the other chamber with one chamber of the two chambers formed in the shock absorber as an upstream and the other chamber as a downstream. A housing having a valve hole that communicates and has an annular valve seat in the middle thereof, a valve body that is movably accommodated in the valve hole and is attached to and detached from the annular valve seat, and a spring seat fixed in the valve hole; In a damping valve having a spring interposed between a valve body and a spring seat and biasing the valve body toward the annular valve seat, a space between the annular valve seat and the spring seat is provided in the spring seat. A first port that communicates with the other chamber, a second port that bypasses the first port and communicates the space with the other chamber, and the valve body is retracted by a predetermined amount in a direction away from the annular valve seat. Shuts off the first port.

  In the damping valve of the present invention, the damping force characteristic when the first port is closed can be freely set independently of the damping force characteristic when the first port is open.

  Therefore, the shock absorber equipped with the damping valve of the present invention exhibits an appropriate damping force to suppress the vehicle body vibration during the traveling of the railway vehicle, particularly during the normal traveling state in which the large earthquake does not occur. In a situation where the vehicle body vibration becomes large due to an earthquake while the vehicle is running, while suppressing the vehicle's ride comfort, it exerts a large damping force characterized by the second port to reduce the vehicle body vibration of the railway vehicle. It can be effectively suppressed. That is, it is possible to achieve both the ride comfort of the vehicle during normal traveling and the suppression of vehicle body vibration due to strong earthquakes.

  Therefore, this damping valve can cause the shock absorber to exhibit an optimum damping force, particularly for suppressing the vibration of the vehicle body of the railway vehicle, and is optimal for the shock absorber for the railway system vibration application.

It is a longitudinal cross-sectional view of the damping valve in one embodiment. It is the schematic of the shock absorber for the vehicle system vibration of a railway vehicle to which the damping valve of one embodiment is applied. It is the figure which showed the damping force characteristic of the shock absorber for vehicle system vibration to which the damping valve of one embodiment was applied. It is a longitudinal cross-sectional view of the damping valve in one modification of one embodiment. It is a longitudinal cross-sectional view of the damping valve in the other modification of one Embodiment. It is the figure which showed the damping force characteristic of the shock absorber for vehicle system vibration to which the conventional damping valve was applied.

  Hereinafter, the damping valve 1 of this invention is demonstrated based on figures. As shown in FIG. 1, the damping valve 1 in one embodiment is embodied in a piston portion of a shock absorber D, and more specifically, pressure chambers R1 as two chambers formed in the shock absorber D. Piston 2 as a housing having valve holes 2a and 2b each having an annular valve seat 4 in the middle and communicating the pressure chamber R1 and pressure chamber R2 with one of R2 being upstream and the other being downstream; 2b, a valve body 5 movably accommodated in the annular valve seat 4, a spring seat 10 fixed in the valve holes 2a, 2b, and an intervening space between the valve body 5 and the spring seat 10. And a coil spring 14 as a spring for urging the valve body 5 toward the annular valve seat 4.

  Further, in the damping valve 1 on the valve hole 2a side, the first is provided in the spring seat 10 and communicates the space L between the annular valve seat 4 and the spring seat 10 in the valve hole 2a to the pressure chamber R2. A port 11 and a second port 12 that bypasses the first port 11 and communicates the space L to the pressure chamber R2 are provided in the spring seat 10 even in the damping valve 1 on the valve hole 2b side. A space L between the annular valve seat 4 and the spring seat 10 in the valve hole 2b communicates with the pressure chamber R1, and the space L bypasses the first port 11 and communicates with the pressure chamber R1. In any damping valve 1, the valve body 5 blocks the first port 11 when the valve body 5 is retracted by a predetermined amount in the direction away from the annular valve seat 4. .

  The damping valve 1 is embodied in a shock absorber D as shown in FIG. The shock absorber D is particularly used for the purpose of suppressing the vehicle body vibration in the lateral direction with respect to the traveling direction of the railway vehicle by being interposed between the vehicle body B and the carriage W of the railway vehicle. The shock absorber D includes a cylinder 21, a piston 2 that is slidably inserted into the cylinder 21, and that defines two pressure chambers R <b> 1 and R <b> 2 that are filled with a fluid such as hydraulic oil, and the cylinder 21. A piston rod 22 that is movably inserted into the piston 21 and connected to the piston 2, an outer cylinder 23 that covers the outer periphery of the cylinder 21 and forms a reservoir R between the cylinder 21, and the cylinder 21 and the outer cylinder 23. A rod guide 24 that closes the end portion and pivotally supports the piston rod 22 and a lid 25 that closes the other end of the cylinder 21 and the outer cylinder 23 are provided. In this case, the shock absorber D is a single piece. Lo There is a type of damper. Of course, a double rod type shock absorber may be used.

  The piston 2 is provided with valve holes 2a and 2b, and the damping valve 1 is installed with the piston 2 as a housing, and the valve bodies 5 are accommodated in the valve holes 2a and 2b with the directions of the valve bodies 5 being alternately arranged. Has been.

  In the shock absorber D, when the piston 2 tries to move to the left in FIG. 2, the pressure in the pressure chamber R1 on the left in the figure rises, and the pressure on the valve hole 2a side is increased by the pressure. When the damping valve 1 is opened, the damping valve 1 exerts a damping force by giving resistance to the liquid flow while allowing the fluid in the pressure chamber R1 to escape to the right pressure chamber R2 in the figure through the valve hole 2a. To do. In addition, the damping valve 1 on the valve hole 2b side receives the pressure of the pressure chamber R1 and remains closed to block the valve hole 2b. That is, the damping valve 1 installed in the valve hole 2a has the pressure chamber R1 as one chamber, which is upstream, and the pressure chamber R2 is the other chamber, which is downstream. The pressure chamber R1 flows toward the downstream pressure chamber R2.

  On the other hand, when the piston 2 tries to move to the right in FIG. 2, the pressure in the right pressure chamber R2 in the figure rises, and the damping valve 1 on the valve hole 2b side opens by the pressure, The damping valve 1 exerts a damping force by giving resistance to the flow of liquid while allowing the fluid in the pressure chamber R2 to escape to the left pressure chamber R1 in the drawing through the valve hole 2b. In addition, the damping valve 1 on the valve hole 2a side receives the pressure of the pressure chamber R2 and remains closed to block the valve hole 2a. That is, the damping valve 1 installed in the valve hole 2b has the pressure chamber R2 as one chamber, which is upstream, and the pressure chamber R1 as the other chamber, which is downstream. The pressure chamber R2 flows toward the downstream pressure chamber R1.

  Thus, the damping valve 1 acts as a damping valve that causes the shock absorber D to exert a damping force when vibration is input to the shock absorber D. In the case of the shock absorber D, the volume of fluid in which the piston rod 22 enters and exits the cylinder 21 is compensated by supplying and discharging the fluid from the reservoir R through the passages 25a and 25b provided in the lid 25. In particular, during the stroke in which the piston rod 22 enters the cylinder 21, the damping valve 26 provided in the middle of the passage 25a is opened and the fluid is discharged from the pressure chamber R2 to the reservoir R. Thus, a resistance is given to the flow of the fluid to increase the internal pressure in the cylinder 21, and a damping force is exhibited in cooperation with the damping valve 1 on the valve hole 2b side. Note that the above-described configuration of the damping valve 1 can be adopted as the damping valve 26. On the other hand, in the process of retracting the piston rod 22 from the cylinder 21, the check valve 27 provided in the middle of the passage 25b is opened and the fluid is supplied from the reservoir R to the pressure chamber R2. Hardly gives resistance to the flow of the fluid.

  Further, the shock absorber D includes a constant orifice 28 that communicates the pressure chamber R1 and the pressure chamber R2 in parallel with the above-described damping valve 1, and the fluid is kept constant until the damping valve 1 is opened. 28, the pressure chambers R1 and R2 are moved back and forth. The constant orifice 28 is provided in the piston 2, but may be provided in the rod guide 24, the cylinder 21, and the lid 25.

  The configuration of the shock absorber D is not limited to the above. For example, the reservoir R, the pressure chamber R1, the pressure chamber R2, and the reservoir R of the shock absorber D are connected in a passage through a passage, and the shock absorber D is expanded and contracted. In the case of a uniflow buffer that circulates fluid in the order of the reservoir R, the pressure chamber R2, the pressure chamber R1, and the reservoir R, the upstream chamber is the pressure chamber R1 and the downstream chamber is the downstream chamber. As the reservoir R, a valve hole that communicates these is provided in the rod guide 24 as a housing, and the damping valve 1 is installed so as to give resistance when a fluid flows from the pressure chamber R1 toward the reservoir R. Good. Further, the damping valve 1 according to the present invention may be applied to the damping valve 26 provided on the lid 25. In this case, the lid 25 is a housing, the upstream one chamber is the pressure chamber R2, and the downstream is the downstream. The other chamber is the reservoir R. The lid 25 may block only the outer cylinder 23 and partition the cylinder 21 and the reservoir R with a member including a check valve 27 and an attenuation valve 26.

  Hereafter, each part of the damping valve 1 will be described in detail below. The piston 2 as a housing is annular, and is provided with valve holes 2a and 2b in which the valve body 5 is accommodated. The damping valve 1 is installed in the piston 2 in opposite directions on the side of the valve holes 2a and 2b. However, since the structure is the same and the description is repeated, a specific structure will be described below with the valve hole 2a as an example. Will be described.

  As shown in FIG. 1, the inner periphery of the lower end in FIG. 1 of the valve hole 2 a is reduced in diameter to form a reduced diameter portion 3, and the annular valve seat 4 is formed by a step portion provided by the formation of the reduced diameter portion 3. Is formed. Further, a screw portion 9 is provided on the inner periphery of the upper end in FIG. 1 of the valve hole 2a, and a spring seat 10 is screwed to the screw portion 9.

  Further, the piston 2 is opened from the side of the valve hole 2a and communicates a space L between the annular valve seat 4 and the spring seat 10 in the valve hole 2a to a pressure chamber R2 as the other chamber. A port 12 is provided. Since the other chamber of the valve hole 2b is the pressure chamber R1, the second port 12 opens from the side of the valve hole 2b and is located between the annular valve seat 4 and the spring seat 10 in the valve hole 2b. Is provided in the piston 2 so as to communicate with the pressure chamber R1 as the other chamber.

  The valve body 5 is accommodated in the valve hole 2a so as to be movable in the axial direction, and a disc-shaped valve body 6 that is attached to and detached from the annular valve seat 4 and a lower end in FIG. A cylindrical valve head 7 and a spring fitting portion 8 protruding to the valve body 6 on the side opposite to the valve head. Further, the valve head 7 is slidably inserted into the reduced diameter portion 3 in the valve hole 2a, and the valve body 5 moves in the axial direction without being displaced by the valve hole 2a with the valve head 7 as a guide. Can be done. In addition, you may make it guide the movement of the valve body 5 by making the outer periphery of the valve main body 6 slidably contact with the inner peripheral surface of the valve hole 2a. A cutout or the like may be provided so as to allow passage of fluid.

  When the lower end of the valve body 6 in FIG. 1 is brought into contact with the upper surface of the annular valve seat 4 in FIG. 1 and is seated, the damping valve 1 is closed and the flow of fluid into the valve hole 2a is blocked. Can be done. Further, the valve head 7 is provided with a U-shaped groove 7a from the distal end to the proximal end, and the lower end of the valve body 6 in FIG. 1 is from the upper surface in FIG. When retreating to the inside of the hole 2a, the groove 7a opens from the reduced diameter portion 3 to the inside of the valve hole 2a according to the retraction amount, and the fluid flows into the valve hole 2a through the groove 7a. It can be done. And according to the retraction amount of the valve body 6 in this valve body 5, the area which the groove | channel 7a faces in the valve hole 2a becomes large, and the valve opening area increases. Note that the shape of the valve head 7 is not limited to the above, and in particular, the valve head 7 may not function as a guide for the movement of the valve body 5.

  In addition to the valve body 5, a spring seat 10 is accommodated in the valve hole 2a described above. The spring seat 10 includes a cylindrical spring fitting portion 10a and a spring fitting portion 10a shown in FIG. A flange-shaped spring receiving portion 10b that is provided at the middle upper end and is screwed to the screw portion 9 of the valve hole 2a, and a first port 11 that communicates from the upper end to the lower end of the spring fitting portion 10a. . The first port 11 communicates the space L between the annular valve seat 4 and the spring seat 10 in the valve hole 2a to a pressure chamber R2 as the other chamber. The area obtained by adding the flow areas of both the first port 11 and the second port 12 is set to be larger than the maximum value of the valve opening area limited between the valve body 5 and the annular valve seat 4. .

  As described above, the spring seat 10 is screwed into the screw portion 9 of the valve hole 2a and is restricted from moving away from the annular valve seat 4. A coil spring 14 is interposed between the spring receiving portion 10b of the spring seat 10 and the valve body 5 in a compressed state, and the urging force of the compressed coil spring 14 is applied to the valve body 5 in the annular valve seat. Acting toward 4.

  Therefore, in the damping valve 1 on the valve hole 2a side, the pressure in the upstream pressure chamber R1 acts on the valve head 7 of the valve body 5, and the force pushing the valve body 5 biases the valve body 5 of the coil spring 14. When the urging force is exceeded, the valve opens, and the fluid that has pushed the valve body 5 and passed through the groove 7a passes through the valve hole 2a, the first port 11 and the second port 12, and then escapes to the downstream pressure chamber R2. It will follow.

  As the pressure acting on the distal end side of the valve body 5 increases, the amount of retreat away from the annular valve seat 4 and inward of the valve hole 2a increases. As the retraction amount increases, the valve body 5 and the annular valve increase. The valve opening area limited by the seat 4 also increases. When the valve body 5 moves backward and the valve body 5 retracts from the annular valve seat 4 to a predetermined amount, the upper end of the spring fitting portion 8 of the valve body 5 in FIG. The opening of the first port 11 provided in the spring fitting portion 10a is controlled while abutting the lower end of the valve body 10a and restricting further movement of the valve body 5 away from the annular valve seat 4. It is supposed to block. The flow area of the second port 12 is at least the valve opening area between the valve body 5 and the annular valve seat 4 when the valve body 5 moves backward from the annular valve seat 4 and abuts against the spring seat 10. It is set to be smaller. Therefore, when the retraction amount of the valve body 5 from the annular valve seat 4 becomes a predetermined retraction amount, the fluid flows from the pressure chamber R1 to the pressure chamber R2 only through the second port 12 because the first port 11 is blocked. Therefore, the flow area of the damping valve 1 as a whole is reduced to the flow area of the second port 12.

  On the other hand, in the damping valve 1 on the valve hole 2b side, the pressure in the pressure chamber R2 acts on the valve head 7 of the valve body 5, and the force pushing the valve body 5 biases the valve body 5 of the coil spring 14. When the force is exceeded, the valve opens, and the fluid that has pushed the valve body 5 and passed through the groove 7a passes through the valve hole 2b, the first port 11 and the second port 12, and then escapes to the pressure chamber R1. Become.

  As the pressure acting on the distal end side of the valve body 5 increases, the amount of retreat away from the annular valve seat 4 and inward of the valve hole 2b increases. As the retraction amount increases, the valve body 5 and the annular valve increase. The valve opening area limited by the seat 4 also increases. Then, when the valve body 5 is moved backward, and the amount of valve body 5 retracted from the annular valve seat 4 reaches a predetermined amount, the spring fitting portion 8 of the valve body 5 collides with the spring fitting portion 10a. Thus, the valve body 5 is restricted from moving further away from the annular valve seat 4, and the valve body 5 closes the opening of the first port 11 provided in the spring fitting portion 10a. . The flow area of the second port 12 is at least the valve opening area between the valve body 5 and the annular valve seat 4 when the valve body 5 moves backward from the annular valve seat 4 and abuts against the spring seat 10. It is set to be smaller.

  Therefore, when the retraction amount of the valve body 5 from the annular valve seat 4 becomes a predetermined retraction amount, the fluid flows from the pressure chamber R2 to the pressure chamber R1 only through the second port 12 because the first port 11 is blocked. Therefore, the flow area of the damping valve 1 as a whole installed in the valve hole 2 b is reduced to the flow area of the second port 12.

  Next, the operation of the damping valve 1 will be described by taking as an example one installed in the valve hole 2a of the shock absorber D. In the damping valve 1 configured as described above, when the piston 2 has a leftward displacement input in FIG. 2, the pressure in the left pressure chamber R1 in the figure rises. However, since the valve does not open until the pressure reaches the valve opening pressure of the damping valve 1, the fluid moves from the pressure chamber R1 to the pressure chamber R2 only through the constant orifice 28. Therefore, the damping force characteristic that is the characteristic of the damping force with respect to the piston speed of the shock absorber D until the damping valve 1 is opened becomes a square characteristic peculiar to the orifice as shown in the section A in FIG. Exhibits a damping force with a relatively high damping coefficient with respect to the piston speed.

  When the moving speed of the piston 2 increases, the pressure in the left pressure chamber R1 in the figure increases and the pressure reaches the valve opening pressure of the damping valve 1, the valve body 5 is The coil spring 14 is compressed by being pressed by the pressure, retreats away from the annular valve seat 4 and opens the valve hole 2a. When the damping valve 1 is opened in this way, the compressed fluid in the left pressure chamber R1 flows into the valve hole 2a and moves to the pressure chamber R2 via the first port 11 and the second port 12. Will do. The shock absorber D applies a resistance to the fluid flow by the damping valve 1 against the leftward movement of the piston 2 to generate a damping force that suppresses the movement of the piston 2. At this time, the resistance at the constant orifice 28 is larger than that of the damping valve 1, and the flow rate flowing through this is small, and the damping force characteristic of the shock absorber D is dominated by the characteristic of the damping valve 1.

  Then, the movement speed of the piston 2 to the left does not reach a predetermined movement speed, and the pressure in the pressure chamber R1 acting on the valve body 5 is retracted until the valve body 5 abuts against the spring seat 10. In the absence, the valve body 5 can be moved away from the annular valve seat 4 to increase the valve opening area in accordance with the pressure increase in the pressure chamber R1 due to the increase in the piston speed. As shown in the section B, the damping force characteristic that increases the damping force with a relatively small inclination with respect to the increase in the piston speed is exhibited.

  In the damping valve 1, when the fluid passes between the valve body 5 and the annular valve seat 4, not only resistance is given to the flow of the fluid, but also the fluid flows to the first port 11 and the first valve 11. When passing through the two ports 12, resistance is given to the flow of the fluid. Therefore, when the fluid that has passed between the valve body 5 and the annular valve seat 4 passes through the first port 11 and the second port 12, the pressure in the space L in the valve hole 2a increases, and this pressure is reduced. As a secondary pressure, the valve body 5 can be urged toward the annular valve seat 4 in the valve closing direction by acting on the back surface side of the valve body 5 in FIG. As described above, the secondary pressure can be arbitrarily set according to the opening areas of the first port 11 and the second port 12, and the opening areas of the first port 11 and the second port 12 are determined after the damping valve 1 is opened. It is also an adjustment element characterizing the damping force characteristic of the shock absorber D.

  Subsequently, the moving speed of the piston 2 to the left (the expansion / contraction speed of the shock absorber D) reaches a predetermined speed, the pressure in the pressure chamber R1 acting on the valve body 5 increases, and the valve body 5 is moved to the spring seat 10. , The valve body 5 closes the first port 11, and the flow area of the damping valve 1 is reduced to the flow area of the second port 12. No matter how much the pressure in the pressure chamber R1 increases due to the subsequent increase in the piston speed, the flow path area cannot be increased any further, and the shock absorber D has a piston as shown in section C in FIG. It exhibits a damping force characteristic that increases the damping force with a large slope (damping coefficient) with respect to an increase in speed. When the first port 11 is opened and enabled, the area obtained by adding the flow areas of both the first port 11 and the second port 12 is set between the valve body 5 and the annular valve seat 4. Since the valve opening area is set to be larger than the restricted valve opening area, the flow of fluid is most restricted between the valve body 5 and the annular valve seat 4 until the valve body 5 closes the first port 11. The damping force characteristic of the shock absorber D is dominated by the restriction made by the valve body 5 and the annular valve seat 4. On the contrary, the damping coefficient in the section C is that the first port 11 is closed and only the second port is effective, so that the damping force characteristic of the shock absorber D is between the valve body 5 and the annular valve seat 4. The characteristics of the second port 12 having a smaller flow path area than the restricted valve opening area become dominant, and the attenuation coefficient in the section C can be freely set by the flow path area of the second port 12.

  Note that the operation of the damping valve 1 installed in the valve hole 2b of the shock absorber D exhibits the same operation as described above when the movement direction of the piston 2 is opposite to the above, and a detailed description thereof will be omitted. To do.

  Thus, in the damping valve 1, the damping force characteristic when the first port 11 is closed can be freely set independently of the damping force characteristic in the state where the first port 11 is opened. is there.

  Therefore, the shock absorber D equipped with the damping valve 1 of the present invention exhibits an appropriate damping force and exhibits a moderate damping force especially during normal traveling, which is a traveling situation in which a large earthquake does not occur. In a situation where the vibration is suppressed and the ride comfort in the vehicle is ensured, and an earthquake occurs while the vehicle is running and the vehicle body vibration becomes large, the large damping force characterized by the second port 12 is exerted, Vehicle vibration can be effectively suppressed. That is, it is possible to achieve both the ride comfort of the vehicle during normal traveling and the suppression of vehicle body vibration due to strong earthquakes.

  Therefore, the damping valve 1 can cause the shock absorber D to exhibit an optimum damping force particularly for suppressing the vibration of the vehicle body of the railway vehicle, and is optimal for the shock absorber D for the vehicle system vibration use of the rail vehicle. Become.

  The second port 12 can also be provided at a position where the spring seat 10 is not blocked by the valve body 5, and as shown in FIG. 4, the second port 12 tapers to the outer periphery of the upper end of the spring fitting portion 8 of the valve body 5. A poppet shape is formed by providing a surface, the tip diameter thereof is set to a diameter that can enter the first port 11 provided in the spring seat 10, and the spring fitting portion 8 is used as a poppet valve body to make the first of the spring seat 10. A poppet valve having a valve seat around the opening of the port 11 may be configured. In this case, the degree of decrease in the flow path area of the first port 11 can be tuned with respect to the retraction of the valve body 5 by the taper angle. Can be avoided, and a sudden change in the damping force characteristic can be prevented.

  Furthermore, as shown in FIG. 5, the first port 11 has a vertical hole 11a that penetrates the spring fitting portion 10a in the axial direction, and a horizontal hole that opens from the side of the spring fitting portion 10a and communicates with the vertical hole 11a. A rod 13 that is slidably inserted into the vertical hole 11 a at the tip of the spring fitting portion 8 of the valve body 5, and the valve body 5 is retracted from the annular valve seat 4. When the rod 13 penetrates deeply into the vertical hole 11a, the rod 13 faces the horizontal hole 11b, and when the retraction amount of the valve body 5 from the annular valve seat 4 reaches a predetermined amount, the rod 13 enters the horizontal hole 11b. It is also possible to adopt a configuration in which the first port 11 is completely opposed and closed. Also in this case, the degree of decrease in the flow area of the first port 11 can be tuned with respect to the retraction of the valve body 5 by setting the shape of the lateral hole 11b and the shape of the tip of the rod 13, so that the first port Therefore, it is possible to avoid a sudden decrease in the flow path area of the damping valve 1 due to the blockage of 11, and to prevent a sudden change in the damping force characteristic.

  In the present embodiment, the spring seat 10 is provided with the vertical hole 11a and the horizontal hole 11b. However, the present invention is not limited thereto, and the vertical hole and the horizontal hole may be provided in the rod 13 of the valve body 5. Further, the second port 12 may be provided on the rod 13.

  As described above, in the present embodiment, the first port 11 provided in the spring seat 10 is closed by the spring fitting portion 8 provided in the valve body 5, but the coil spring 14 is necessarily fitted. This is not an essential configuration, and a configuration in which the outer diameter of the spring fitting portion 8 in each drawing is smaller than the inner diameter of the coil spring 14 and the coil spring 14 is loosely fitted may be employed. The same applies to the spring seat 10, and the outer diameter of the spring fitting portion 10 a can be set smaller than the inner diameter of the coil spring 14.

  The predetermined speed of the shock absorber D when the valve body 5 abuts on the spring seat 10 and the first port 11 is closed can be arbitrarily set. It is good to set it to the expansion / contraction speed expected to reach when the vehicle body vibrates due to an earthquake. Further, when the predetermined speed is reached, the valve body 5 may abut against the spring seat 10 so that the first port 11 is closed, so that the valve body 5 closes the first port 11. What is necessary is just to set the predetermined reverse amount at the time of performing according to predetermined speed.

 Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the details shown or described.

  The present invention can be used for a damping valve of a shock absorber.

DESCRIPTION OF SYMBOLS 1 Damping valve 2 Piston 2a, 2b as a housing Valve hole 3 Diameter reduction part 4 Annular valve seat 5 Valve body 6 Valve main body 7 Valve head 7a Groove 8 Spring fitting part 9 Screw part 10 Spring seat 10a Spring fitting part 10b Spring Receiving portion 11 First port 11a Vertical hole 11b Horizontal hole 12 Second port 13 Rod 14 Coil spring 21 Cylinder 22 Piston rod 23 Outer cylinder 24 Rod guide 25 Lid 25a, 25b Passage 26 Damping valve 27 Check valve 28 Constant orifice D Buffer B Body L Space R Reservoir R1, R2 Pressure chamber W Bogie

Claims (2)

A housing provided with a valve hole having an annular valve seat in the middle thereof, with one chamber of the two chambers formed in the shock absorber as the upstream and the other chamber as the downstream, the one chamber communicated with the other chamber; The valve body is movably accommodated in the valve hole and is attached to and detached from the annular valve seat, the spring seat fixed in the valve hole, and the valve body annularly interposed between the valve body and the spring seat. In a damping valve having a spring urged toward the valve seat, the spring seat is provided with a first port that communicates the space between the annular valve seat and the spring seat to the other chamber, and bypasses the first port A damping valve is provided, wherein a second port for communicating the space with the other chamber is provided, and the valve body shuts off the first port when the valve body is retracted by a predetermined amount in a direction away from the annular valve seat. 2. The damping valve according to claim 1, wherein when the expansion / contraction speed of the shock absorber reaches a predetermined speed, the valve body abuts on the spring seat to shut off the first port.

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