Air spring devices for railway vehicles

Abstract

To provide an air spring device for a railway vehicle which has a simple structure without feedback control and steadily attenuates vibrations both in a low frequency range having an eigen frequency of an air spring and in a high frequency range having an eigen frequency of an axle spring.SOLUTION: An air spring device 10 of a railway vehicle has: an air spring 4 installed between a truck 2 and a vehicle body 3; and an auxiliary air chamber 6 communicated with an air chamber 4S of an air spring body 4H via a fixed throttle 51. The auxiliary air chamber has: a first auxiliary air chamber 61 communicated with the air spring via the fixed throttle; and a second auxiliary air chamber 62 communicated with the first auxiliary air chamber via a second fixed throttle 52 whose throttle diameter is formed to have a smaller throttle diameter than the fixed throttle. Between the first and second auxiliary air chambers, a bypass circuit 5B which has a relief valve 54 that makes a third fixed throttle 53 formed to have a throttle diameter smaller than the fixed throttle but larger than the second fixed throttle is in parallel with a fixed throttle circuit 5A with the second fixed throttle 52.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air spring device for a railway vehicle, and more particularly to an air spring device for a railway vehicle that is capable of damping vibrations in both a low-frequency region having the natural frequency of the air spring and a high-frequency region having the natural frequency of the axle spring. [Background technology]

[0002] In general, railway vehicles connect the wheels that make up the bogie to the bogie frame via axle springs, and connect the bogie frame to the carbody via air springs to dampen the vibrations that the wheels receive from the rails, thereby improving the ride comfort for passengers on the carbody.The air spring is composed of an air chamber in the air spring body, which is made up of a rubber bellows and a laminated rubber section, an auxiliary air chamber installed in the bogie, and a throttle (orifice) formed between the two air chambers, and is structured so that vibrations are damped by the pressure loss of the air passing through this throttle.

[0003] On the other hand, air springs, which are made of rubber bellows or similar materials and have excellent vibration isolation properties at high frequencies due to their flexibility, often have a natural frequency that resonates at low frequencies (around 1 to 2 Hz), so the orifice diameter is uniquely selected to achieve significant vibration damping in that low-frequency range. However, in the case of an orifice with a uniquely selected diameter (a fixed orifice), when the vibration frequency is high and the amplitude is large, the flow rate of air passing through the orifice (orifice flow rate) increases, causing a sudden increase in the pressure difference before and after the orifice. As a result, in the high-frequency range (around 10 Hz) where the shaft spring has its natural frequency, the damping force of the orifice is significantly reduced, resulting in the problem of insufficient vibration damping performance in that range.

[0004] In order to address such problems, for example, Patent Document 1 discloses an air spring device for railway vehicles, which is used as a secondary spring for railway vehicles, and in which a throttle connects the air spring main body and an auxiliary air chamber, the device is configured with a variable throttle mechanism that continuously changes the size of the throttle, and is provided with a throttle control mechanism that detects vibrations of the car body with a sensor or the like and provides a damping force proportional to the vibration speed.

[0005] Specifically, as shown in Figure 7, an air spring device 100 for a railway vehicle is disclosed, in which a vertical vibration accelerometer 102 is provided on the floor of a car body 101, and a height sensor 104 is provided between the car body 101 and a bogie frame 103, and the detection signals thereof are input to a controller 105, which then inputs a control signal to a variable throttle mechanism 107 provided in an air spring 106 in order to generate a damping force proportional to the vertical vibration speed of the car body 101 according to the theory of the skyhook damper.

[0006] 8, the variable throttle mechanism 107 is made up of a disk valve 110 and the like, the throttle of which is variable by a control motor 109 such as a step motor or a servo motor. The disk valve 110 has, for example, a partition wall 111 separating the air spring main body 106a and the auxiliary air chamber 106b, on which a plurality of small circular holes 112 are arranged circumferentially, and a rotating disk 114 on which a plurality of through holes 113 are arranged in the same circumferential position as the small circular holes 112 is rotated by the overlap control motor 109 to control the size of the throttle formed by the overlap of the small circular holes 112 and the through holes 113. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 6-239230 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the air spring device 100 for a railway vehicle described in Patent Document 1, a vertical vibration accelerometer 102 is provided on the floor surface of the carbody 101, and a height sensor 104 is provided between the carbody 101 and the bogie frame 103, and their detection signals are input to a controller 105, which in turn inputs a control signal to a variable throttle mechanism 107 provided on the air spring 106 in order to generate a damping force proportional to the vertical vibration speed of the carbody 101 according to the theory of the skyhook damper. Therefore, the information on the vertical vibration speed of the carbody 101 is feedback-controlled to the variable throttle mechanism 107. Therefore, when the vertical vibration speed of the carbody 101 increases, a delay in the response of the throttle diameter in the variable throttle mechanism 107 is likely to occur, which may make it impossible to solve the problem of insufficient vibration damping performance being obtained in the high frequency range (around 10 Hz) where the axle spring has its natural frequency.

[0009]

[0005] Variable throttle mechanism 107 is comprised of a disk valve 110 whose aperture is variable by a control motor 109 such as a step motor or servo motor, and disk valve 110 has, for example, a partition wall 111 separating air spring main body 106a and auxiliary air chamber 106b, with a plurality of small circular holes 112 arranged circumferentially, and a rotating disk 114 having a plurality of through holes 113 arranged in the same circumferential direction as small circular holes 112, which is rotated by overlap control motor 109 to control the size of the aperture formed by the overlap of small circular holes 112 and through holes 113. Therefore, variable throttle mechanism 107 is formed in the narrow gap between air spring main body 106a and auxiliary air chamber 106b, resulting in a complex structure. This poses the problem that replacement of variable throttle mechanism 107 when it breaks down and regular inspection of variable throttle mechanism 107 are complicated.

[0010] The present invention has been made to solve such problems, and has an object to provide an air spring device for a railway vehicle that has a simple structure without using feedback control and is capable of stably damping vibrations in both the low-frequency region where the air spring has its natural frequency and the high-frequency region where the axle spring has its natural frequency. [Means for solving the problem]

[0011] In order to achieve the above object, an air spring device for a railway vehicle according to the present invention has the following configuration. (1) An air spring device for a railway vehicle, comprising: an air spring installed between a bogie and a car body of the railway vehicle; and an auxiliary air chamber formed in the bogie and communicating with the air chamber of the air spring main body via a fixed throttle, the auxiliary air chamber includes a first auxiliary air chamber that is in communication with the air chamber of the air spring body via the fixed orifice, and a second auxiliary air chamber that is in communication with the first auxiliary air chamber via a second fixed orifice that is formed with a smaller orifice diameter than the fixed orifice, Between the first auxiliary air chamber and the second auxiliary air chamber, a bypass circuit having a third fixed throttle formed with a throttle diameter smaller than that of the fixed throttle but larger than that of the second fixed throttle and a relief valve that opens the chamber when a predetermined pressure difference occurs is connected in parallel to a fixed throttle circuit having the second fixed throttle.

[0012] In the present invention, the auxiliary air chamber comprises a first auxiliary air chamber which is connected to the air chamber of the air spring body via a fixed orifice, and a second auxiliary air chamber which is connected to the first auxiliary air chamber via a second fixed orifice which is formed with a smaller orifice diameter than the fixed orifice, and between the first auxiliary air chamber and the second auxiliary air chamber is a bypass circuit which has a third fixed orifice which is formed with a smaller but larger orifice diameter than the fixed orifice but a relief valve which opens the first auxiliary air chamber when a predetermined pressure difference occurs, and this bypass circuit is connected in parallel to the fixed orifice circuit which has the second fixed orifice.Therefore, the fixed orifice circuit and the bypass circuit each play their respective roles for vibrations in both low frequency ranges which have the natural frequency of the air spring and high frequency ranges which have the natural frequency of the axle spring, thereby ensuring stable vibration damping performance.

[0013] That is, low-frequency vibrations having the natural frequency of the air spring can be largely damped by the pressure loss of the air passing through the fixed orifice that connects the air chamber of the air spring main body and the first auxiliary air chamber, and then passing through the second fixed orifice, which is formed with a smaller orifice diameter than the fixed orifice. Also, high-frequency vibrations having the natural frequency of the axle spring can be damped by the second fixed orifice when the amplitude is small, because the flow rate of air passing through the second fixed orifice (orifice flow rate) is small and the pressure difference between the pressures in the first and second auxiliary air chambers does not exceed a predetermined value. However, when the amplitude increases and the pressure difference exceeds the predetermined value, the relief valve is opened and the vibrations can be damped by the pressure loss of the air passing through the third fixed orifice.

[0014] Furthermore, the fixed throttle, second fixed throttle, and third fixed throttle all have a simple throttle structure in which the throttle diameter is set to a predetermined size, and no feedback control is used. Therefore, even if the vertical vibration speed of the vehicle body increases, there is no delay in the throttle diameter, as occurs with a variable throttle mechanism, and the vibration damping performance of the air spring can be stably ensured in the high-frequency range containing the natural frequency of the axle spring.

[0015] Therefore, according to the present invention, it is possible to provide an air spring device for a railway vehicle that has a simple structure without using feedback control and is capable of stably damping vibrations in both the low-frequency region having the natural frequency of the air spring and the high-frequency region having the natural frequency of the axle spring.

[0016] (2) In the air spring device for a railway vehicle described in (1), The first auxiliary air chamber and the second auxiliary air chamber are formed inside the bogie frame of the bogie, and the bypass circuit is formed outside the bogie frame of the bogie.

[0017] In the present invention, the first auxiliary air chamber and the second auxiliary air chamber are formed inside the bogie frame of the bogie, and therefore the first auxiliary air chamber and the second auxiliary air chamber can be easily formed by dividing the internal space of the frame members constituting the bogie frame with a partition plate. Furthermore, since the bypass circuit is formed outside the bogie frame of the bogie, the bypass circuit can be formed with a simple structure by piping the third fixed throttle and the relief valve outside the bogie frame. Therefore, the relief valve and other components constituting the bypass circuit can be easily inspected, repaired, or replaced from outside the bogie frame. This makes it possible to ensure the vibration damping performance of the air spring with even greater stability.

[0018] (3) In the air spring device for a railway vehicle described in (1) or (2), The second auxiliary air chamber is formed to have a volume larger than the volume of the first auxiliary air chamber.

[0019] In the present invention, the volume of the second auxiliary air chamber is larger than the volume of the first auxiliary air chamber, so that air passing from the air chamber of the air spring main body through the fixed orifice due to vehicle body vibration does not stagnate in the first auxiliary air chamber but can quickly move through the second or third fixed orifice to the second auxiliary air chamber. This allows the air chamber of the air spring main body to be in nearly direct communication with the second auxiliary air chamber via the second or third fixed orifice, thereby improving the responsiveness of the damping force of the second or third fixed orifice. As a result, the vibration damping performance of the air spring can be further improved.

[0020] (4) In the air spring device for a railway vehicle described in any one of (1) to (3), the auxiliary air chambers include a right first auxiliary air chamber and a right second auxiliary air chamber that communicate with the air springs arranged on the right side of the vehicle, and a left first auxiliary air chamber and a left second auxiliary air chamber that communicate with the air springs arranged on the left side of the vehicle, A second bypass circuit having a second relief valve that opens the right and left second auxiliary air chambers when a predetermined pressure difference occurs is connected between the right and left second auxiliary air chambers. Here, the "right side of the vehicle" means the right side when facing the direction of travel of the vehicle, and the "left side of the vehicle" means the left side when facing the direction of travel of the vehicle.

[0021] In the present invention, the auxiliary air chambers include a right first auxiliary air chamber and a right second auxiliary air chamber that communicate with the air springs located on the right side of the vehicle, and a left first auxiliary air chamber and a left second auxiliary air chamber that communicate with the air springs located on the left side of the vehicle, and a second bypass circuit having a second relief valve that connects the right second auxiliary air chamber and the left second auxiliary air chamber when a predetermined pressure difference occurs is connected between them.Therefore, if the pressure in the right second auxiliary air chamber or the left second auxiliary air chamber increases excessively due to the vehicle body tilting (rolling) to the left or right, etc., and a predetermined pressure difference occurs, the second relief valve opens to equalize the pressures in both chambers, thereby suppressing a decrease in the damping force of the second fixed orifice or the third fixed orifice and enabling the damping force of the second fixed orifice or the third fixed orifice to be equalized.

[0022] (5) In the air spring device for a railway vehicle according to any one of (1) to (4), A plurality of bypass circuits each having a third fixed throttle with a different throttle diameter and a relief valve that communicates with the first auxiliary air chamber and the second auxiliary air chamber at a different pressure difference are connected in parallel between the first auxiliary air chamber and the second auxiliary air chamber.

[0023] In the present invention, multiple bypass circuits each having a third fixed orifice with a different orifice diameter and a relief valve that communicates with the first auxiliary air chamber and the second auxiliary air chamber are connected in parallel between the first auxiliary air chamber and the second auxiliary air chamber, so that the multiple bypass circuits can operate separately to exhibit their respective vibration damping capabilities in response to high-frequency vibrations having a plurality of natural frequencies. As a result, stable vibration damping performance can be ensured even in response to the specific vibrations that occur in running sections with different track conditions, such as bridges and tunnels. [Effects of the Invention]

[0024] According to the present invention, it is possible to provide an air spring device for a railway vehicle that has a simple structure without using feedback control and is capable of stably damping vibrations in both the low-frequency region having the natural frequency of the air spring and the high-frequency region having the natural frequency of the axle spring. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic cross-sectional view of an air spring device for a railway vehicle illustrating one aspect of the present embodiment. [Figure 2] 2 is a schematic diagram of an air circuit in the air spring device of the railway vehicle shown in FIG. 1. FIG. [Figure 3] 3A and 3B are diagrams illustrating the operation of the air circuit shown in FIG. 2, in which (A) shows an explanatory diagram illustrating the operation when the pressure in the first auxiliary air chamber and the pressure in the second auxiliary air chamber are smaller than a predetermined pressure difference, and (B) shows an explanatory diagram illustrating the operation when the pressure in the first auxiliary air chamber and the pressure in the second auxiliary air chamber are larger than a predetermined pressure difference. [Figure 4] 2 is a vibration damping characteristic diagram showing the relationship between the vibration frequency and the response magnification in the air spring device of the railway vehicle shown in FIG. 1. FIG. [Figure 5] 2 is a schematic diagram of an air circuit according to a first modified example of the air spring device for the railway vehicle shown in FIG. 1. FIG. [Figure 6] 1. FIG. 4 is a schematic diagram of an air circuit according to a second modified example of the air spring device for the railway vehicle shown in FIG. [Figure 7] 1 is a schematic cross-sectional view of an air spring device for a railway vehicle disclosed in Patent Document 1. FIG. [Figure 8] 8 is a schematic diagram of the variable throttle mechanism of the railcar air spring device shown in FIG. 7. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] Next, a railway vehicle air spring device representing one aspect of this embodiment will be described in detail with reference to the drawings. Specifically, the configuration and operation method of the railway vehicle air spring device according to this embodiment will be described in detail, and then the configurations and operation methods of first and second modified examples will be described.

[0027] <Configuration and operation method of the air spring device of this railway vehicle> First, the configuration and operating method of the air spring device for a railway vehicle will be described with reference to Figures 1 to 4. Figure 1 shows a schematic cross-sectional view of an air spring device for a railway vehicle representing one aspect of this embodiment. Figure 2 shows a schematic configuration diagram of an air circuit in the air spring device for a railway vehicle shown in Figure 1. Figure 3 is an explanatory diagram of the operation of the air circuit shown in Figure 2, where (A) shows an explanatory diagram of operation when the pressure in the first auxiliary air chamber and the pressure in the second auxiliary air chamber are smaller than a predetermined pressure difference, and (B) shows an explanatory diagram of operation when the pressure in the first auxiliary air chamber and the pressure in the second auxiliary air chamber are larger than the predetermined pressure difference. Figure 4 shows a vibration damping characteristic diagram showing the relationship between the vibration frequency and the response magnification in the air spring device for a railway vehicle shown in Figure 1.

[0028] As shown in FIGS. 1 to 3, an air spring device 10 for a railway vehicle representing one aspect of this embodiment is an air spring device 10 for a railway vehicle that includes an air spring 4 installed between a bogie 2 and a carbody 3 of the railway vehicle 1, and an auxiliary air chamber 6 formed in the bogie 2 and communicating with an air chamber 4S of an air spring main body 4H via a fixed orifice 51. Here, the bogie 2 includes a wheel set 8 that runs on a rail RL laid on a track FL, and a bogie frame 21 to which the air spring 4 is attached, and the wheel set 8 is connected to the bogie frame 21 via an axle spring 7. The air springs 4 are disposed on both the right and left sides of the vehicle. Here, the "right side of the vehicle" refers to the right side when facing the direction of travel of the vehicle, and the "left side of the vehicle" refers to the left side when facing the direction of travel of the vehicle.

[0029] The auxiliary air chamber 6 is provided with a first auxiliary air chamber 61 that communicates with the air chamber 4S of the air spring main body 4H via a fixed orifice 51, and a second auxiliary air chamber 62 that communicates with the first auxiliary air chamber 61 via a second fixed orifice 52 that has a smaller orifice diameter than the fixed orifice 51. Here, the fixed orifice 51 is installed in the partition wall that separates the air chamber 4S of the air spring main body 4H from the first auxiliary air chamber 61. The second fixed orifice 52 is installed in the partition wall that separates the first auxiliary air chamber 61 and the second auxiliary air chamber 62, but it may also be installed in the external piping that connects the first auxiliary air chamber 61 and the second auxiliary air chamber 62.

[0030] The diameter of fixed orifice 51 need only be large enough to allow air to move approximately freely between air chamber 4S of air spring main body 4H and first auxiliary air chamber 61, and need only be large enough to cause almost no pressure loss in the air passing through. The diameter of second fixed orifice 52 is set to a size that can significantly attenuate the pressure loss of air passing through second fixed orifice 52 in the low-frequency range (around 1 to 2 Hz) that includes the natural frequency of air spring 4. For example, the diameter of second fixed orifice 52 is preferably set to about 1 / 2 to 1 / 3 times the diameter of fixed orifice 51.

[0031] Furthermore, between the first auxiliary air chamber 61 and the second auxiliary air chamber 62, a bypass circuit 5B is connected in parallel to the fixed throttle circuit 5A having the second fixed throttle 52. The bypass circuit 5B has a third fixed throttle 53, which has a throttle diameter smaller than that of the fixed throttle 51 but larger than that of the second fixed throttle 52, and a relief valve 54 that opens the circuit when a predetermined pressure difference ΔP occurs. The throttle diameter of the third fixed throttle 53 is set to a size that allows significant attenuation by the pressure loss of the air passing through the third fixed throttle 53 in the high frequency range (around 10 Hz) that includes the natural frequency of the axle spring 7.

[0032] The relief valve 54 includes a relief valve 54a that opens when the pressure P1b in the first auxiliary air chamber 61 becomes greater than a predetermined pressure difference ΔP (for example, approximately 80 to 120 kPa) above the pressure P2b in the second auxiliary air chamber 62, and a relief valve 54b that opens when the pressure P2b in the second auxiliary air chamber 62 becomes greater than the pressure P1b in the first auxiliary air chamber 61 by the predetermined pressure difference ΔP (for example, approximately 80 to 120 kPa), and both relief valves 54a, 54b are arranged in parallel.

[0033] Since the air spring device 10 of this railway vehicle has the above-mentioned configuration, the fixed throttle circuit 5A and the bypass circuit 5B each share their roles in terms of vibrations Q1 and Q2 in both the low frequency range (around 1 to 2 Hz) where the air spring 4 has its natural frequency, and the high frequency range (around 10 Hz) where the axle spring 7 has its natural frequency, thereby ensuring stable vibration damping performance.

[0034] 3(A), low-frequency vibration Q1 (around 1 to 2 Hz) having the natural frequency of the air spring 4 passes almost without attenuation through fixed orifice 51, which connects air chamber 4S of air spring main body 4H with first auxiliary air chamber 61, and then passes through second fixed orifice 52, which is formed with a smaller orifice diameter than fixed orifice 51. Then, due to the pressure loss of the air passing through second fixed orifice 52, low-frequency vibration Q1 (around 1 to 2 Hz) having the natural frequency of the air spring 4 can be significantly attenuated.

[0035] Furthermore, when the amplitude f1 is small, the high-frequency (around 10 Hz) vibration Q2 having the natural frequency of the axle spring 7 can be damped by the second fixed orifice 52 because the flow rate of air passing through the second fixed orifice 52 (or orifice flow rate) is small and the pressure difference (|P1a-P2a|) between the pressure P1a in the first auxiliary air chamber 61 and the pressure P2a in the second auxiliary air chamber 62 does not exceed the predetermined value ΔP.

[0036] However, as shown in FIG. 3(B), when the amplitude f2 of the high-frequency (near 10 Hz) vibration Q2 having the natural frequency of the axle spring 7 increases and the flow rate of air passing through the second fixed orifice 52 (throttle flow rate) increases, causing the pressure difference (|P1b-P2b|) to exceed the predetermined value ΔP, the relief valve 54 (54a, 54b) of the bypass circuit 5B is opened and the pressure loss of the air passing through the third fixed orifice 53 can attenuate the pressure difference.

[0037] Furthermore, the fixed throttle 51, the second fixed throttle 52 and the third fixed throttle 53 are all of a simple throttle structure in which the throttle diameter is set to a predetermined size and no feedback control is used, so even if the vertical vibration speed of the vehicle body 3 increases, there is no delay in the throttle diameter as occurs with a variable throttle mechanism, and the vibration damping performance of the air spring 4 can be stably ensured in the high frequency range (around 10 Hz) where the axle spring 7 has its natural frequency.

[0038] Therefore, according to the present air spring device 10 for a railway vehicle, it is possible to provide an air spring device 10 for a railway vehicle 1 that can stably damp vibrations in both the low-frequency region having the natural frequency of the air spring 4 and the high-frequency region having the natural frequency of the axle spring 7, with a simple structure without using feedback control.

[0039] In addition, in the air spring device 10 of this railway vehicle, it is preferable that the first auxiliary air chamber 61 and the second auxiliary air chamber 62 are formed within the bogie frame 21 of the bogie 2, and the bypass circuit 5B is formed outside the bogie frame 21 of the bogie 2.

[0040] Because the first auxiliary air chamber 61 and the second auxiliary air chamber 62 are formed inside the bogie frame 21 of the bogie 2, the internal space of the frame members constituting the bogie frame 21 can be divided by a partition plate to easily form the first auxiliary air chamber 61 and the second auxiliary air chamber 62. Furthermore, because the bypass circuit 5B is formed outside the bogie frame 21 of the bogie 2, the bypass circuit 5B can be formed with a simple structure by piping the third fixed throttle 53 and the relief valve 54 (54a, 54b) to the outside of the bogie frame 21. Therefore, the relief valve 54 and other components constituting the bypass circuit 5B can be easily inspected from the outside of the bogie frame 21, and repairs, replacements, etc. can also be performed.

[0041] Furthermore, in the present air spring device 10 for a railway vehicle, it is preferable that the volume of the second auxiliary air chamber 62 is larger than the volume of the first auxiliary air chamber 61. For example, it is even more preferable that the volume of the second auxiliary air chamber 62 is approximately 3 to 10 times the volume of the first auxiliary air chamber 61. It is also preferable that the volume of the entire auxiliary air chamber 6 is approximately 1.5 to 3 times the volume of the air chamber 4S of the air spring main body 4H.

[0042] In this case, air passing from the air chamber 4S of the air spring main body 4H through the fixed orifice 51 in response to vibrations Q1 and Q2 of the vehicle body 3 can quickly move to the second auxiliary air chamber 62 through the second fixed orifice 52 or the third fixed orifice 53 without accumulating in the first auxiliary air chamber 61. This allows the air chamber 4S of the air spring main body 4H to be in substantially direct communication with the second auxiliary air chamber 62 via the second fixed orifice 52 or the third fixed orifice 53, thereby improving the responsiveness of the damping force of the second fixed orifice 52 or the third fixed orifice 53. As a result, the vibration damping performance of the air spring 4 can be further improved.

[0043] Next, the vibration damping characteristics, which represent the relationship between the vibration frequency and the response magnification factor in the air spring device 10 of this railway vehicle, will be explained using Figure 4. In Figure 4, the vertical axis represents the response magnification factor, and the horizontal axis represents the vibration frequency. The response magnification factor refers to the ratio of the sprung displacement of the air spring 4 to the unsprung displacement of the axle spring 7, and more specifically, the ratio of the vertical displacement of the carbody 3 to the vertical displacement of the wheelset 8. Therefore, the smaller the response magnification factor, the better the vibration damping performance, including the axle spring resonance frequency, of the air spring device. Here, we will show the results of a simulation of the vibration damping characteristics of the air spring device 10 of this railway vehicle, and, as a comparative example, the results of a simulation of the vibration damping characteristics of a conventional air spring device in which the air spring is connected to the auxiliary air chamber via a fixed orifice, with the orifice diameters of the fixed orifice being (large), (medium), and (small).

[0044] As shown in Figure 4, in the air spring device of the prior art, when the diameter of the fixed orifice is (large), the response magnification increases significantly in the low-frequency region (around 1 to 2 Hz) where the natural frequency of the air spring 4 is present, but the response magnification only increases slightly in the high-frequency region (around 10 Hz) where the natural frequency of the axle spring 7 is present. Also, in the air spring device of the prior art, when the diameter of the fixed orifice is (medium) or (small), the response magnification decreases significantly in the low-frequency region (around 1 to 2 Hz) where the natural frequency of the air spring 4 is present, compared to when the diameter of the fixed orifice is (large), but in the high-frequency region (around 10 Hz) where the natural frequency of the axle spring 7 is present, the response magnification increases significantly, compared to when the diameter of the fixed orifice is (large).

[0045] That is, in the air spring device of the prior art, the larger the diameter of the fixed orifice, the higher the vibration damping performance in the high frequency range (around 10 Hz) where the axle spring 7 has its natural frequency, but the lower the vibration damping performance in the low frequency range (around 1 to 2 Hz) where the air spring 4 has its natural frequency, and the smaller the diameter of the fixed orifice, the higher the vibration damping performance in the low frequency range (around 1 to 2 Hz) where the air spring 4 has its natural frequency, but the lower the vibration damping performance in the high frequency range (around 10 Hz) where the axle spring 7 has its natural frequency. Therefore, it can be seen that the air spring device of the prior art cannot stably damp vibration in both the low frequency range where the air spring 4 has its natural frequency, and the high frequency range where the axle spring 7 has its natural frequency.

[0046] In contrast, in the case of the present invention (air spring device 10 of this railway vehicle), in the low frequency range (around 1 to 2 Hz) where the air spring 4 has its natural frequency, the response magnification ratio decreases to approximately the same extent as when the aperture diameter of the fixed orifice in the air spring device of the prior art is (medium) or (small), and in the high frequency range (around 10 Hz) where the axle spring 7 has its natural frequency, the response magnification ratio decreases to approximately the same extent as when the aperture diameter of the fixed orifice in the air spring device of the prior art is (large).

[0047] From the above results, it was found that the air spring device 10 of this railway vehicle can stably damp vibrations in both the low frequency region (around 1 to 2 Hz) where the air spring 4 has its natural frequency, and the high frequency region (around 10 Hz) where the axle spring 7 has its natural frequency.

[0048] <Modifications of the air spring device of the present railway vehicle> Next, an air spring device 10B for a railway vehicle according to a first modified example and an air spring device 10C for a railway vehicle according to a second modified example will be described with reference to Figures 5 and 6. Figure 5 shows a schematic configuration diagram of an air circuit of the first modified example in the air spring device for a railway vehicle shown in Figure 1. Figure 6 shows a schematic configuration diagram of an air circuit of the second modified example in the air spring device for a railway vehicle shown in Figure 1.

[0049] (First Modification) As shown in Figure 5, the air spring device 10B for a railway vehicle according to this first modified example has, in the auxiliary air chamber 6, a right first auxiliary air chamber 61R and a right second auxiliary air chamber 62R which communicate with the air spring 4R arranged on the right side of the vehicle, and a left first auxiliary air chamber 61L and a left second auxiliary air chamber 62L which communicate with the air spring 4L arranged on the left side of the vehicle, and a second bypass circuit 5C having a second relief valve 55 (55a, 55b) which opens the connection between the right second auxiliary air chamber 62R and the left second auxiliary air chamber 62L when a predetermined pressure difference occurs is connected between them.

[0050] The air spring 4R on the right side of the vehicle is connected to a right first auxiliary air chamber 61R via a right fixed orifice 51R, and the right first auxiliary air chamber 61R is connected to a right second auxiliary air chamber 62R via a right second fixed orifice 52R formed with a smaller orifice diameter than the right fixed orifice 51R. In addition, between the right first auxiliary air chamber 61R and the right second auxiliary air chamber 62R, a right bypass circuit 5RB having a right third fixed orifice 53R formed with a smaller orifice diameter than the right fixed orifice 51R and larger than the right second fixed orifice 52R and a relief valve 54R (54Ra, 54Rb) that opens the chamber when a predetermined pressure difference ΔP occurs is connected in parallel to a right fixed orifice circuit 5RA having a right second fixed orifice 52R.

[0051] Furthermore, the air spring 4L on the left side of the vehicle is connected to a first left auxiliary air chamber 61L via a left fixed orifice 51L, and the first left auxiliary air chamber 61L is connected to a second left auxiliary air chamber 62L via a second left fixed orifice 52L formed with a smaller orifice diameter than the left fixed orifice 51L. Between the first left auxiliary air chamber 61L and the second left auxiliary air chamber 62L, a left bypass circuit 5LB having a third left fixed orifice 53L formed with a smaller orifice diameter than the left fixed orifice 51L but larger than the second left fixed orifice 52L, and a relief valve 54L (54La, 54Lb) that opens the air chambers when a predetermined pressure difference ΔP occurs, is connected in parallel to the left fixed orifice circuit 5LA having the second left fixed orifice 52L. These configurations are the same as those of the air spring device 10 of this railway vehicle described above, and detailed description thereof will be omitted.

[0052] According to the air spring device 10B for a railway vehicle relating to this first modified example, a second bypass circuit 5C having a second relief valve 55 (55a, 55b) that connects the right second auxiliary air chamber 62R and the left second auxiliary air chamber 62L when a predetermined pressure difference occurs is connected between them.Therefore, when the pressure in the right second auxiliary air chamber 62R or the pressure in the left second auxiliary air chamber 62L increases excessively due to the carbody 3 tilting (rolling) to the left or right, etc., and a predetermined pressure difference ΔP occurs, the second relief valve 55 (55a, 55b) opens to equalize the pressures in both chambers, thereby suppressing a decrease in the damping force of the second fixed orifice 52 (52R, 52L) or the third fixed orifice 53 (53R, 53L) and enabling the damping force of the second fixed orifice 52 (52R, 52L) or the third fixed orifice 53 (53R, 53L) to be equalized.

[0053] (Second Modification) As shown in Figure 6, in the air spring device 10C for a railway vehicle according to this second modified example, multiple bypass circuits 5B1, 5B2 are connected in parallel between the first auxiliary air chamber 61 and the second auxiliary air chamber 62. The bypass circuits 5B1, 5B2 have third fixed throttles 531, 532 with different throttle diameters and relief valves 541, 542 that communicate with each other at different pressure differences.

[0054] The auxiliary air chamber 6 is similar to the air spring device 10 for railway vehicles described above in that it is equipped with a first auxiliary air chamber 61 that is connected to the air chamber 4S of the air spring 4 via a fixed orifice 51, and a second auxiliary air chamber 62 that is connected to the first auxiliary air chamber 61 via a second fixed orifice 52 that is formed with a smaller orifice diameter than the fixed orifice 51, and therefore detailed explanation will be omitted.

[0055] In addition, the relief valves 541, 542 include relief valves 541a, 542a that open when the pressure in the first auxiliary air chamber 61 becomes greater than a predetermined pressure difference from the pressure in the second auxiliary air chamber 62, and relief valves 541b, 542b that open when the pressure in the second auxiliary air chamber 62 becomes greater than the pressure in the first auxiliary air chamber 61 by a predetermined pressure difference.

[0056] In one bypass circuit 5B1, relief valves 541a and 541b are arranged in parallel, and in the other bypass circuit 5B2, relief valves 542a and 542b are arranged in parallel. The pressure difference at which relief valves 541a and 541b in one bypass circuit 5B1 open is set to a different value from the pressure difference at which relief valves 542a and 542b in the other bypass circuit 5B2 open. Here, an example is shown in which there are two bypass circuits 5B1 and 5B2, but the number of bypass circuits 5B1 and 5B2 is not necessarily limited to two and may be three or more.

[0057] According to air spring device 10C for a railway vehicle according to the second modification, multiple bypass circuits 5B1, 5B2 each having third fixed orifices 531, 532 with different orifice diameters and relief valves 541, 542 that communicate with each other at different pressure differences are connected in parallel between first auxiliary air chamber 61 and second auxiliary air chamber 62, so that multiple bypass circuits 5B1, 5B2 can operate separately to exhibit their respective vibration damping performance in response to high-frequency vibrations having multiple natural frequencies. Therefore, stable vibration damping performance can be ensured even in response to specific vibrations that occur in running sections of the line with different conditions, such as bridges and tunnels.

[0058] <Action and effect> According to the air spring devices 10, 10B, 10C for railway vehicles according to the present embodiment described above in detail, the auxiliary air chambers 6, 6R, 6L are provided with first auxiliary air chambers 61, 61R, 61L that communicate with the air chamber 4S of the air spring main body 4H via fixed orifices 51, 51R, 51L, and second auxiliary air chambers 62, 62R, 62L that communicate with the first auxiliary air chambers 61, 61R, 61L via second fixed orifices 52, 52R, 52L that are formed with a smaller orifice diameter than the fixed orifices 51, 51R, 51L, and between the first auxiliary air chambers 61, 61R, 61L and the second auxiliary air chambers 62, 62R, 62L, Bypass circuits 5B, 5B1, 5B2 having larger third fixed orifices 53, 53R, 53L, 531, 532 and relief valves 54, 54R, 54L, 541, 542 that open when a predetermined pressure difference ΔP occurs are connected in parallel to fixed orifice circuits 5A, 5RA, 5LA having second fixed orifices 52, 52R, 52L. Therefore, the fixed orifice circuits 5A, 5RA, 5LA and the bypass circuits 5B, 5B1, 5B2 share roles with each other to ensure stable vibration damping performance for vibrations in both low frequency (around 1 to 2 Hz) having the natural frequency of the air springs 4, 4R, 4L and high frequency (around 10 Hz) having the natural frequency of the axle spring 7.

[0059] In other words, low-frequency (around 1 to 2 Hz) vibration Q1 having the natural frequency of the air springs 4, 4R, 4L can be greatly damped by the pressure loss of the air passing through the fixed orifices 51, 51R, 51L that connect the air chamber 4S of the air spring main body 4H to the first auxiliary air chambers 61, 61R, 61L, and then passing through the second fixed orifices 52, 52R, 52L, which have a smaller orifice diameter than the fixed orifices 51, 51R, 51L. Furthermore, when the amplitude f1 is small, the flow rate of air passing through the second fixed orifices 52, 52R, 52L (throttle flow rate) is small and the pressure difference (|P1a - P2a|) between the pressure P1a in the first auxiliary air chamber 61, 61R, 61L and the pressure P2a in the second auxiliary air chamber 62, 62R, 62L does not exceed a predetermined value ΔP, so the high-frequency vibration Q2 (around 10 Hz) having the natural frequency of the axle spring 7 is damped by the second fixed orifices 52, 52R, 52L. When the amplitude f2 increases and the pressure difference (|P1a - P2a|) exceeds the predetermined value ΔP, the relief valves 54 (54a, 54b), 54R, 54L, 541, 542 are opened and the vibration Q2 can be damped by the pressure loss of the air passing through the third fixed orifices 53, 53R, 53L, 531, 532.

[0060] Furthermore, the fixed orifice 51, the second fixed orifice 52, 52R, 52L and the third fixed orifice 53, 53R, 53L, 531, 532 are all simple orifice structures with orifice diameters set to predetermined sizes and do not use feedback control, so even if the vertical vibration speed of the vehicle body 3 increases, there is no delay in the orifice diameter as occurs with a variable orifice mechanism, and the vibration damping performance of the air spring 4 can be stably ensured in the high frequency range (around 10 Hz) where the axle spring 7 has its natural frequency.

[0061] Therefore, according to this embodiment, it is possible to provide air spring devices 10, 10B, and 10C for railway vehicles that have a simple structure without using feedback control and can stably damp vibrations in the low-frequency region having the natural frequency of the air springs 4, 4R, and 4L and the high-frequency region having the natural frequency of the axle spring 7.

[0062] Furthermore, according to this embodiment, the first auxiliary air chambers 61, 61R, 61L and the second auxiliary air chambers 62, 62R, 62L are formed inside the bogie frame 21 of the bogie 2, and therefore the first auxiliary air chambers 61, 61R, 61L and the second auxiliary air chambers 62, 62R, 62L can be easily formed by dividing the internal space of the frame members constituting the bogie frame 21 with a partition plate. Furthermore, since the bypass circuits 5B, 5B1, 5B2 are formed outside the bogie frame 21 of the bogie 2, the bypass circuits 5B, 5B1, 5B2 can be formed with a simple structure by piping and connecting the third fixed throttles 53, 53R, 53L, 531, 532 and the relief valves 54 (54a, 54b), 54R, 54L, 541, 542 to the outside of the bogie frame 21. Therefore, the relief valves 54 (54a, 54b), 54R, 54L, 541, 542, etc. constituting the bypass circuits 5B, 5B1, 5B2 can be easily inspected, and repairs, replacements, etc. can be easily performed from the outside of the bogie frame 21. Therefore, the vibration damping performance of the air springs 4, 4R, 4L can be ensured more stably.

[0063] In addition, according to this embodiment, the volume of the second auxiliary air chambers 62, 62R, 62L is made larger than the volume of the first auxiliary air chambers 61, 61R, 61L, so that air passing from the air chamber 4S of the air spring main body 4H through the fixed orifices 51, 51R, 51L in conjunction with vibration of the vehicle body 3 does not stagnate in the first auxiliary air chambers 61, 61R, 61L, but can quickly move to the second auxiliary air chambers 62, 62R, 62L by passing through the second fixed orifices 52, 52R, 52L or the third fixed orifices 53, 53R, 53L, 531, 532. Therefore, the air chamber 4S of the air spring main body 4H and the second auxiliary air chambers 62, 62R, 62L can be connected almost directly via the second fixed orifices 52, 52R, 52L or the third fixed orifices 53, 53R, 53L, 531, 532, thereby improving the responsiveness of the damping force of the second fixed orifices 52, 52R, 52L or the third fixed orifices 53, 53R, 53L, 531, 532. As a result, the vibration damping performance of the air springs 4, 4R, 4L can be further improved.

[0064] Furthermore, according to this embodiment, the auxiliary air chamber 6 includes a right first auxiliary air chamber 61R and a right second auxiliary air chamber 62R that communicate with the air spring 4R arranged on the right side of the vehicle, and a left first auxiliary air chamber 61L and a left second auxiliary air chamber 62L that communicate with the air spring 4L arranged on the left side of the vehicle. A second bypass circuit 5C having a second relief valve 55 (55a, 55b) that opens the right second auxiliary air chamber 62R and the left second auxiliary air chamber 62L when a predetermined pressure difference occurs is connected between the right second auxiliary air chamber 62R and the left second auxiliary air chamber 62L. If the pressure in the right second auxiliary air chamber 62R or the pressure in the left second auxiliary air chamber 62L rises excessively due to tilting (rolling) to the left or right, causing a predetermined pressure difference ΔP, the second relief valve 55 (55a, 55b) opens to equalize the pressure in both chambers, thereby suppressing a decrease in the damping force of the second fixed orifice 52 (52R, 52L) or the third fixed orifice 53 (53R, 53L) and equalizing the damping force of the second fixed orifice 52 (52R, 52L) or the third fixed orifice 53 (53R, 53L).

[0065] Furthermore, according to this embodiment, multiple bypass circuits 5B1, 5B2 each having third fixed orifices 531, 532 with different orifice diameters and relief valves 541, 542 that communicate with each other at different pressure differences are connected in parallel between the first auxiliary air chambers 61, 61R, 61L and the second auxiliary air chambers 62, 62R, 62L, so that the multiple bypass circuits 5B1, 5B2 can operate separately to exhibit their respective vibration damping capabilities against high-frequency vibrations having multiple natural frequencies. Therefore, stable vibration damping performance can be ensured even against specific vibrations that occur in running sections with different route conditions, such as bridges and tunnels. [Industrial Applicability]

[0066] The present invention can be used as an air spring device for railway vehicles that can damp vibrations in both the low frequency region having the natural frequency of the air spring and the high frequency region having the natural frequency of the axle spring. [Explanation of symbols]

[0067] 1. Railway vehicles 2 carts 3. Body 4, 4R, 4L air spring 4H air spring body 4S air chamber 5A fixed iris circuit 5B, 5B1, 5B2 bypass circuits 5RB, 5LB bypass circuit 5C Second bypass circuit 6 Auxiliary Air Chamber 10, 10B, 10C Air spring device for railway vehicle 21 Bogie frame 51, 51R, 51L fixed aperture 52, 52R, 52L Second fixed aperture 53, 53R, 53L 3rd fixed aperture 54, 55 Relief valve 61, 61R, 61L 1st auxiliary air chamber 62, 62R, 62L Second auxiliary air chamber 531, 532 Third fixed aperture 541, 542 Relief valve

Claims

1. An air spring device for a railway vehicle, comprising: an air spring installed between a bogie and a car body of the railway vehicle; and an auxiliary air chamber formed in the bogie and communicating with an air chamber of an air spring main body via a fixed throttle, the auxiliary air chamber includes a first auxiliary air chamber that is in communication with the air chamber of the air spring body via the fixed orifice, and a second auxiliary air chamber that is in communication with the first auxiliary air chamber via a second fixed orifice that is formed with a smaller orifice diameter than the fixed orifice, an air spring device for a railway vehicle, wherein a bypass circuit having a third fixed orifice formed with a orifice diameter smaller than that of the fixed orifice but larger than that of the second fixed orifice and a relief valve which opens the chamber when a predetermined pressure difference occurs is connected between the first auxiliary air chamber and the second auxiliary air chamber in parallel with a fixed orifice circuit having the second fixed orifice.

2. 2. The air spring device for a railway vehicle according to claim 1, an air spring device for a railway vehicle, characterized in that the first auxiliary air chamber and the second auxiliary air chamber are formed within a bogie frame of the bogie, and the bypass circuit is formed outside the bogie frame of the bogie.

3. 3. The air spring device for a railway vehicle according to claim 1 or 2, 10. An air spring device for a railway vehicle, wherein the second auxiliary air chamber has a volume larger than the volume of the first auxiliary air chamber.

4. The air spring device for a railway vehicle according to any one of claims 1 to 3, the auxiliary air chambers include a right first auxiliary air chamber and a right second auxiliary air chamber communicating with the air springs arranged on the right side of the vehicle, and a left first auxiliary air chamber and a left second auxiliary air chamber communicating with the air springs arranged on the left side of the vehicle, a second bypass circuit having a second relief valve that opens the second auxiliary air chamber when a predetermined pressure difference occurs, connected between the second auxiliary air chamber for right use and the second auxiliary air chamber for left use.

5. The air spring device for a railway vehicle according to any one of claims 1 to 4, an air spring device for a railway vehicle, characterized in that a plurality of bypass circuits, each having a third fixed orifice with a different orifice diameter and a relief valve that communicates with the first auxiliary air chamber and the second auxiliary air chamber, are connected in parallel between the first auxiliary air chamber and the second auxiliary air chamber.

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