Axle box support device and bogie for railway vehicles

Abstract

To provide an axle box support device that can prevent shortening of the product life by suppressing the stretching of the cylindrical laminated rubber when the bogie is a standalone unit, and to provide the axle box support device thereof. [Solution] The cylindrical laminated rubber 40 is provided with a displacement suppression means 4Z2 that suppresses the vertical displacement of the outermost outer tube 42 relative to the cylindrical portion 21. The displacement suppression means 4Z2 is configured to release the suppression of the vertical downward displacement of the outer tube 42 relative to the cylindrical portion 21 when the vertical downward tensile force on the outer tube 42 by the cylindrical laminated rubber 40 due to the vertical upward displacement of the outer tube 42 reaches a predetermined value. The amount of vertical upward displacement of the outer tube 42 when the tensile force reaches the predetermined value is less than a preset value.

Description

Technical Field

[0001] The present invention relates to a railcar axle box support device that elastically supports an axle box relative to a bogie frame and includes laminated rubber functioning as a primary spring, as well as a bogie and a railcar provided with the railcar axle box support device.

Background Art

[0002] Conventionally, in a bogie for a railcar, a railcar axle box support device (hereinafter simply referred to as "axle box support device") interposed between a bogie frame and an axle box is known (see, for example, Patent Document 1). The axle box support device elastically supports the axle box relative to the bogie frame. The axle box support device includes a coil spring functioning as a primary spring, and laminated rubber. The coil spring mainly receives a load acting in the vertical direction by expanding and contracting in the vertical direction. On the other hand, the laminated rubber mainly receives a load acting in the horizontal direction (the track direction and the sleeper direction) by deforming in the horizontal direction.

[0003] Incidentally, the applicant may adopt a tandem type as the configuration of the axle box support device in the bogie of a railcar. Fig. 11 is an explanatory diagram for describing the tandem type axle box support device adopted by the applicant, and Fig. 12 is a cross-sectional view taken along the Z-Z line in Fig. 11. Note that a part of Fig. 11 is shown in cross section.

[0004] The axle box support device 803 as the prior art is interposed between the bogie frame 801 and the axle box 802 that together constitute the bogie 800, and is attached to the end of the side beam 801B extending in the track direction at the end of the bogie frame 801 in the sleeper direction. The axle box support device 803 mainly includes a lower shaft spring seat 901, an upper shaft spring seat 902, a coil spring 903, a first cylindrical laminated rubber 904, and a second cylindrical laminated rubber 905.

[0005] The lower axle spring seat 901 is fixed to the upper surface of the axle box 802. The lower axle spring seat 901 also has a cylindrical support shaft portion 910 that extends coaxially with the spring centerline O9, and a flange portion 911 that protrudes circumferentially from the lower end of the support shaft portion 910.

[0006] The upper shaft spring seat 902 is fixed to the bottom surface of the top plate 801B1 of the side beam 801B. The upper shaft spring seat 902 also has a cylindrical portion 912 that extends coaxially with the spring centerline O9, a flange portion 913 that protrudes circumferentially from the upper end of the cylindrical portion 912, and an annular portion 914 that extends upward from the inward end of the flange portion 913.

[0007] The coil spring 903 functions as the primary spring of the axle box support device 803, and primarily receives loads acting in the vertical direction by expanding and contracting in the vertical direction. The coil spring 903 is interposed between the flange portion 913 of the upper axle spring seat 902 and the flange portion 911 of the lower axle spring seat 901. Inside the coil spring 903, the support shaft portion 910 and the cylindrical portion 912 are arranged coaxially with the spring centerline O9.

[0008] The first cylindrical laminated rubber 904 functions as the primary spring of the axle box support device 803, and mainly receives loads acting in the track direction by deforming in the horizontal direction. The first cylindrical laminated rubber 904 is concentrically arranged inside the coil spring 903 and has an annular inner tube 921, an outer tube 922, and an arc-shaped curved metal plate 923 and rubber plate 924.

[0009] The inner circumferential tube 921 of the first cylindrical laminated rubber 904 has the support shaft portion 910 of the lower shaft spring seat 901 inserted into it. The inner circumferential tube 921 is fixed to the support shaft portion 910. The outer circumferential tube 922 of the first cylindrical laminated rubber 904 is fitted into a fitting groove 912m formed on the inner circumferential surface 912S of the cylindrical portion 912 of the upper shaft spring seat 902. That is, the vertical displacement of the outer circumferential tube 922 relative to the cylindrical portion 912 is constrained.

[0010] The first cylindrical laminated rubber 904 is then press-fitted into the cylindrical portion 912 of the upper shaft spring seat 902 in a compressed state with respect to the horizontal direction, or in other words, with respect to the radial direction with respect to the spring centerline O9.

[0011] The second cylindrical laminated rubber 905 functions as the primary spring of the axle box support device 803, and mainly receives loads acting in the direction of the sleepers by deforming in the horizontal direction. The second cylindrical laminated rubber 905 is located on the inside side of the axle box 802 in the direction of the track, and is concentric and cylindrical, and like the first cylindrical laminated rubber 904, it has an annular inner tube and an outer tube, and an arc-shaped curved metal plate and rubber plate.

[0012] A vertically extending support shaft 804a, formed in the inner cylinder member 804, is coaxially inserted into the inner circumference tube of the second cylindrical laminated rubber 905. The inner cylinder member 804 is attached to the bottom plate 801B2 of the side beam 801B via a support seat 805. The inner circumference tube of the second cylindrical laminated rubber 905 is fixed to the support shaft 804a.

[0013] The outer tube of the second cylindrical laminated rubber 905 is positioned within the cylindrical ring 806 by upper and lower C-rings provided at the upper and lower ends inside the cylindrical ring 806, so as not to move. The cylindrical ring 806 is attached to the axle box 802 via support arms 807.

[0014] The second cylindrical laminated rubber 905 is then press-fitted into the cylindrical ring 806 in a compressed state with respect to the horizontal direction, or in other words, with respect to the radial direction with respect to the central axis.

[0015] Here, we will explain the behavior of the outer tube 922 of the first cylindrical laminated rubber 904. When a car body (not shown) is placed on a bogie 800 equipped with an axle box support device 803, the bogie 800 receives a load from the car body. At this time, the coil spring 903 is compressed to some extent. Therefore, for example, if the vertical displacement between the bogie frame 801 and the axle box 802 is free, when the car body is removed from the bogie 800 for inspection, the load that the bogie 800 was receiving from the car body is released, and the coil spring 903 extends. In this case, the bogie frame 801 rises as the coil spring 903 extends. As a result, the cylindrical portion 912 of the upper axle spring seat 902 fixed to the bogie frame 801 also rises, and the outer tube 922 of the first cylindrical laminated rubber 904, which is constrained by the cylindrical portion 912, is pulled upward and displaced vertically upward. Here, since the inner circumferential tube 921 of the first cylindrical laminated rubber 904 is fixed to the support shaft portion 910, the outer circumferential tube 922 of the first cylindrical laminated rubber 904 moves relative to the inner circumferential tube 921. In other words, the inside of the first cylindrical laminated rubber 904 deforms.

[0016] The limit for vertical displacement (vertical displacement) of the outer tube 922 of the first cylindrical laminated rubber 904 is approximately the amount of displacement caused by vibration. In other words, the vertical displacement that occurs when the bogie is empty is outside the range of the limit. If the vertical displacement exceeds the limit, the product life of the first cylindrical laminated rubber 904 will be shortened. Therefore, when removing the car body from the bogie 800, such as during bogie inspection, a jig 809 is installed between the receiving piece member 808 provided at the tip of the side beam 801B and the axle box 802 to restrain the upward movement of the bogie frame 801 (cylindrical portion 912 of the upper axle spring seat 902) relative to the axle box 802, as shown in Figure 11, thereby preventing vertical upward displacement (extension) of the first cylindrical laminated rubber 904 exceeding the allowable limit. [Prior art documents] [Patent Documents]

[0017] [Patent Document 1] Japanese Patent Publication No. 2014-201083 [Overview of the Initiative] [Problems that the invention aims to solve]

[0018] However, when removing the car body from the bogie, such as during inspection of the bogie, there is a risk that the worker may forget to attach the jig 809.

[0019] The present invention was made to solve the aforementioned problems, and aims to provide an axle box support device that can prevent shortening of product life by suppressing vertical upward displacement (elongation) of the cylindrical laminated rubber when the bogie is a standalone unit, and a bogie including the axle box support device. [Means for solving the problem]

[0020] To achieve the above objective, an axle box support device and a bogie for a railway vehicle according to one aspect of the present invention have the following features.

[0021] (1) Axle box support device for railway vehicles, The bogie supporting the vehicle body includes a coil spring interposed between the bogie frame and the axle box, which is expandable and contractible in the vertical direction, and a cylindrical laminated rubber interposed between the member on the bogie frame side to which the coil spring is fixed and the member on the axle box side, which is arranged concentrically, wherein the axle box is elastically supported by the bogie frame by the coil spring and the cylindrical laminated rubber. The member on the bogie frame side has a cylindrical portion that is open at the bottom, The cylindrical laminated rubber has an outer peripheral tube positioned on the outermost side, and the outer peripheral tube is press-fitted radially into the cylindrical portion with the cylindrical portion in contact with the cylindrical portion. The cylindrical portion can be raised as the coil spring extends during the transition from an empty state with the car body to a state where the bogie does not support the car body. The outer tube is equipped with a displacement suppression means for suppressing vertical displacement of the outer tube relative to the cylindrical portion, The displacement suppressing means is configured to release the suppression of the vertically downward displacement of the outer tube relative to the cylindrical portion when a vertically downward tensile force on the outer tube from the cylindrical laminated rubber accompanying the vertically upward displacement of the outer tube reaches a predetermined value, The amount of vertically upward displacement of the outer tube when the tensile force reaches the predetermined value is less than a preset specified value. According to the aspect described in the above (1), the outer tube is firmly fixed to the cylindrical portion by the displacement suppressing means until the tensile force reaches the predetermined value. Therefore, during normal use (within the range of the normal maximum displacement of the outer tube during service), the outer tube follows the vertical displacement (rising and lowering) of the cylindrical portion, and the function of the cylindrical laminated rubber can be maintained. Here, if the suppression of the vertical displacement of the outer tube relative to the cylindrical portion is not released during the transition from the unloaded state to the bogie standalone state, the outer tube will continue to displace vertically upward, so that the amount of vertically upward displacement of the outer tube will exceed the allowable value when the transition from the unloaded state to the bogie standalone state is completed. However, when the vertically downward tensile force on the outer tube from the cylindrical laminated rubber accompanying the vertically upward displacement of the outer tube reaches a predetermined value, in other words, during the transition from the unloaded state to the bogie standalone state, the displacement suppressing means releases the suppression of the vertically downward displacement of the outer tube relative to the cylindrical portion, so that the outer tube displaces vertically downward. As a result, the final amount of vertically upward displacement of the outer tube can be reduced.

[0022] (2) In the axle box support device for a railway vehicle according to (1), a locking portion protruding radially inward is formed on the inner side surface of the cylindrical portion and below the outer tube, The value obtained by subtracting the distance from the outer peripheral tube to the locking portion from the extension amount of the coil spring during the transition from the unloaded vehicle state to the bogie standalone state may be less than the specified value. According to the aspect described in the above (2), when the cylindrical portion further rises after the tensile force reaches a predetermined value, the outer peripheral tube is locked by the locking portion. Therefore, it is possible to prevent the cylindrical laminated rubber from slipping out of the member on the bogie frame side. Furthermore, when the cylindrical portion further rises after the tensile force reaches the predetermined value, it is possible to prevent the vertically upward displacement amount of the outer peripheral tube from exceeding the specified value. In the axle box support device for railway vehicles according to (3) or (1), as the displacement suppressing means, a surface treatment may be applied to a portion of the inner side surface of the cylindrical portion that is in contact with the outer peripheral tube such that the maximum static friction force becomes the predetermined value. According to the aspect described in the above (4), it is possible to reduce the final vertically upward displacement amount of the outer peripheral tube while suppressing an increase in the number of components. In the axle box support device for railway vehicles according to (4) or (1), a locking portion protruding radially inward is formed on the inner side surface of the cylindrical portion and below the outer peripheral tube, As the displacement suppressing means, a special member made of a material that breaks when the tensile force reaches the predetermined value may be provided between the locking portion and the outer peripheral tube. According to the aspect described in the above (4), it is possible to further securely fix the outer peripheral tube to the cylindrical portion until the tensile force reaches the predetermined value, and reduce the final vertically upward displacement amount of the outer peripheral tube. Effects of the Invention

[0023] According to the present invention, it is possible to prevent the shortening of the product life by suppressing the upward extension of the cylindrical laminated rubber when the bogie becomes standalone. Brief Description of the Drawings

[0024] [Figure 1] It is a schematic side view of a vehicle. [Figure 2] It is a schematic side view of a bogie. [Figure 3] It is a plan view of a bogie frame. [Figure 4]This is a side view of a shaft box support device according to the first embodiment of the present invention. [Figure 5] Figure 4 is a plan view of the axle box support device. [Figure 6] This is a cross-sectional view along line XX in Figure 4. [Figure 7] This is a cross-sectional view along the YY line in Figure 4. [Figure 8A] This is an explanatory diagram illustrating the behavior of the cylindrical section and the first cylindrical laminated rubber when transitioning from an empty state to a single bogie state. [Figure 8B] This is an explanatory diagram illustrating the behavior of the cylindrical section and the first cylindrical laminated rubber when transitioning from an empty state to a single bogie state. [Figure 8C] This is an explanatory diagram illustrating the behavior of the cylindrical section and the first cylindrical laminated rubber when transitioning from an empty state to a single bogie state. [Figure 8D] This is an explanatory diagram illustrating the behavior of the cylindrical section and the first cylindrical laminated rubber when transitioning from an empty state to a single bogie state. [Figure 8E] This is an explanatory diagram illustrating the behavior of the cylindrical section and the first cylindrical laminated rubber when transitioning from an empty state to a single bogie state. [Figure 8F] This is an explanatory diagram illustrating the behavior of the cylindrical section and the first cylindrical laminated rubber when transitioning from an empty state to a single bogie state. [Figure 8G] This is an explanatory diagram illustrating the behavior of the cylindrical section and the first cylindrical laminated rubber when transitioning from an empty state to a single bogie state. [Figure 9] This graph shows the relationship between the vertically downward load acting on the bogie frame during the transition from an empty state to a single bogie state, and the vertically upward displacement of the outer tube. [Figure 10] This is a side view of a shaft box support device according to a second embodiment of the present invention. [Figure 11] This is a side view of a conventional axle box support device. [Figure 12] This is a cross-sectional view along the ZZ line in Figure 11. [Modes for carrying out the invention]

[0025] <First Embodiment> Each embodiment of the axle box support device for railway vehicles (hereinafter simply referred to as "axle box support device") and the bogie according to the present invention will be described with reference to the drawings.

[0026] First, an overview of the bogie 101 and the axle box support device 4 of the first embodiment will be described. Figure 1 is a schematic side view of the vehicle 100 equipped with the bogie 101. Figure 2 is a schematic side view of the bogie 101 equipped with the axle box support device 4.

[0027] Vehicle 100 consists of a commuter train and comprises two bogies 101 and one car body 102. The two bogies 101 are arranged side by side, spaced apart along the direction of the track. The car body 102 is supported by the two bogies 101.

[0028] The bogie 101 comprises a wheelset 1, axle boxes 2, a bogie frame 3, axle box support devices 4, and a car body support device 5. The wheelset 1 comprises an axle (not shown) and a wheel 1A. The axle extends in the direction of the sleepers. The axle centerline O2 passes through the center of the axle, and the wheel 1A is connected to the axle. Therefore, the wheel 1A rotates about the axle centerline O2. The axle box 2 is located at the end of the axle. The axle box 2 houses a bearing (not shown) that rotatably supports the axle. The bogie frame 3 forms the framework of the bogie 101 and is located between the axle box support device 4 and the car body support device 5. The axle box support device 4 is interposed between the bogie frame 3 and the axle box 2 and supports the axle box 2 relative to the bogie frame 3. The car body support device 5 is installed on the bogie frame 3 and supports the car body 102 relative to the bogie frame 3. Therefore, the bogie frame 3 receives vertical and horizontal loads from the car body 102 via the car body support device 5.

[0029] Next, the details of the axle box support device 4 will be described. Figure 3 is a plan view of the bogie frame 3, Figure 4 is a front view showing the axle box support device 4 when the car body 102 is empty, Figure 5 is a plan view of the axle box support device 4 shown in Figure 4, Figure 6 is a cross-sectional view along line XX in Figure 4, and Figure 7 is a cross-sectional view along line YY in Figure 4. Note that in Figure 4, only a portion is shown in cross-section.

[0030] The bogie frame 3 comprises one crossbeam 3A extending in the direction of the sleepers and two side beams 3B extending in the direction of the track from both ends of the crossbeam 3A. Axle box support devices 4 are provided at each end of the side beams 3B. In other words, the bogie frame 3 is provided with a total of four axle box support devices 4. The load that the bogie frame 3 receives from the car body 102 is transmitted to each axle box support device 4. In the following, the direction of the track from one wheelset of the bogie 101 toward the other wheelset will be simply referred to as the "inside direction of the track," and the direction of the track from one wheelset of the bogie 101 toward the opposite direction from the other wheelset will be simply referred to as the "outside direction of the track."

[0031] The axle box support device 4 is installed between the bogie frame 3 and the axle box 2, more specifically between the side beam 3B and the axle box 2. The axle box support device 4 is a so-called "tandem type axle box support device" and elastically supports the axle box 2 with respect to the bogie frame 3 (side beam 3B). Therefore, the axle box support device 4 has the function of absorbing small vibrations transmitted from the rails when the vehicle 100 is running, preventing them from being transmitted to the bogie frame 3, and ensuring stable running of the vehicle 100. The axle box support device 4 mainly comprises a lower axle spring seat 10, an upper axle spring seat 20, a coil spring 30, a first cylindrical laminated rubber 40, and a second cylindrical laminated rubber 50.

[0032] The lower axle spring seat 10 is positioned between the axle box 2 and the side beam 3B and is supported by the axle box 2. In other words, the lower axle spring seat 10 is a component of the axle box 2. The lower axle spring seat 10 also has a support shaft portion 11 and a flange portion 12. The support shaft portion 11 is formed in a cylindrical shape with its center coaxial with the spring centerline O1. The spring centerline O1 extends vertically perpendicular to the axle centerline O2. The flange portion 12 protrudes radially outward from the lower end of the support shaft portion 11 around its entire circumference.

[0033] The upper axle spring seat 20 is positioned between the axle box 2 and the side beam 3B and is supported by the top plate 3B1 of the side beam 3B. In other words, the upper axle spring seat 20 is a component on the bogie frame 3 side. The upper axle spring seat 20 also has a cylindrical portion 21, a flange portion 22, and an annular portion 23. The cylindrical portion 21 is made of steel and is formed in a cylindrical shape with its center coaxially with the spring centerline O1. The support shaft portion 11 of the lower axle spring seat 10 is coaxially inserted into the cylindrical portion 21 from below. The flange portion 22 protrudes radially outward from the upper end of the cylindrical portion 21 around its entire circumference. The annular portion 23 extends upward from the radially inward end of the flange portion 22. The annular portion 23 has a mounting hole 23h for attaching a rubber cap 24. The rubber cap 24 prevents water droplets and dust from entering the inside of the cylindrical portion 21.

[0034] Furthermore, the inner surface 21S of the cylindrical portion 21 is provided with an upper locking portion 210, a sliding portion 211, and a lower locking portion 212 around its entire circumference. On the inner surface 21S, a step is formed where the inner diameter becomes slightly larger, or in other words, the thickness of the cylindrical portion 21 becomes thinner, as it moves from the upper end to the lower end, specifically around the center in the vertical direction. This step constitutes the upper locking portion 210. The portion of the inner surface 21S below the upper locking portion 210 constitutes the sliding portion 211. Therefore, the upper locking portion 210 protrudes radially inward (towards the spring centerline O1) relative to the sliding portion 211. The lower locking portion 212 is formed in an annular shape and protrudes radially inward (towards the spring centerline O1) from the lower end of the sliding portion 211. In the first embodiment, the length of the upper locking portion 210 protruding from the sliding portion 211 and the length of the lower locking portion 212 protruding from the sliding portion 211 are approximately the same. Furthermore, the length of the upper locking portion 210 protruding from the sliding portion 211 and the length of the lower locking portion 212 protruding from the sliding portion 211 are approximately the same as the thickness of the outer perimeter pipe 42, which will be described later.

[0035] Furthermore, the area between the upper locking portion 210 and the lower locking portion 212 on the inner surface 21S of the cylindrical portion 21 is surface-treated to achieve a coefficient of friction lower than that between the other parts of the cylindrical portion 21 and the steel member. Hereinafter, the portion of the inner surface 21S that has been surface-treated will be referred to as the "inner surface friction reduction portion 21S1".

[0036] Thus, the lower axle spring seat 10 and the upper axle spring seat 20 are arranged coaxially with the spring centerline O1 between the axle box 2 and the side beam 3B. The lower axle spring seat 10 is joined to the upper surface of the axle box 2 via a liner 19 at a flange portion 12. On the other hand, the upper axle spring seat 20 is joined to the bottom surface of the top plate 3B1 of the side beam 3B via a vibration-damping rubber 29 at a flange portion 22.

[0037] The coil spring 30 is positioned coaxially with the spring centerline O1 between the flange portion 22 of the upper shaft spring seat 20 and the flange portion 12 of the lower shaft spring seat 10, and functions as the primary spring of the shaft box support device 4. In detail, the coil spring 30 is fixed to the flange portion 22 of the upper shaft spring seat 20 and the flange portion 12 of the lower shaft spring seat 10, and mainly receives loads acting in the vertical direction by expanding and contracting in the vertical direction. A cylindrical portion 21 and a support shaft portion 11 are also coaxially inserted inside the coil spring 30.

[0038] The first cylindrical laminated rubber 40 is coaxially arranged inside the coil spring 30 and functions as the primary spring of the axle box support device 4. The first cylindrical laminated rubber 40 also has an inner circumferential tube 41, an outer circumferential tube 42, a metal plate 43, and a rubber plate 44. The inner circumferential tube 41, outer circumferential tube 42, metal plate 43, and rubber plate 44 are arranged concentrically. The inner circumferential tube 41 and outer circumferential tube 42 are made of steel and are formed in an annular shape. The metal plate 43 and rubber plate 44 are curved in an arc shape.

[0039] The rubber portion 40A, which is formed in a roughly fan shape by the integration of a metal plate 43 and a rubber plate 44, is configured to be elastically deformable. In each rubber portion 40A, the metal plate 43 is provided in two layers radially between the inner circumferential tube 41 and the outer circumferential tube 42. The circumferential length of each rubber portion 40A increases radially outward. The rubber plate 44 is bonded by vulcanization molding between the inner circumferential tube 41 and the inner metal plate 43, between each metal plate 43, and between the outer circumferential tube 42 and the outer metal plate 43. A gap 40B is also formed between a pair of rubber portions 40A.

[0040] The support shaft portion 11 of the lower shaft spring seat 10 is inserted into the inner circumference tube 41 of the first cylindrical laminated rubber 40. The inner circumference tube 41 is fixed to the support shaft portion 11. The outer circumference tube 42 of the first cylindrical laminated rubber 40 is in contact with the inner surface friction reduction portion 21S1 formed on the inner surface 21S of the cylindrical portion 21 of the upper shaft spring seat 20. The first cylindrical laminated rubber 40 is press-fitted into the cylindrical portion 21 of the upper shaft spring seat 20 in a compressed state with respect to the horizontal direction, or in other words, in the radial direction with respect to the spring centerline O1. Therefore, the cylindrical portion 21 of the upper shaft spring seat 20 is subjected to a radially outward load (pressure force) from the first cylindrical laminated rubber 40.

[0041] Furthermore, the first cylindrical laminated rubber 40 is positioned so that each gap 40B faces the front and rear sides (track direction side) of the vehicle 100. Therefore, the first cylindrical laminated rubber 40 mainly receives loads acting in the track direction by deforming in the horizontal direction.

[0042] Furthermore, Figure 4 shows the axle box support device 4 when the vehicle body 102 is empty. Hereafter, the position of the outer tube 42 in the empty state shown in Figure 4 will be referred to as the "normal position". When the outer tube 42 is held in the normal position, the first cylindrical laminated rubber 40 is not deformed, and no force (restoring force) is generated inside the first cylindrical laminated rubber 40 that tries to return it to its original state, and the outer tube 42 is not subjected to tensile force from the rubber part 40A.

[0043] Furthermore, the vertical gap between the outer pipe 42 and the lower locking portion 212 is referred to as the "displacement suppression gap L1," the vertical length of the displacement suppression gap L1 is referred to as the "displacement suppression gap length," and the displacement suppression gap length in the unloaded state is referred to as the "initial value of the displacement suppression gap." The displacement suppression gap L1 and other related details will be described later.

[0044] Next, before describing the second cylindrical laminated rubber 50, the surrounding structure of the second cylindrical laminated rubber 50 will be described. A cylindrical housing member 6 is positioned on the inside of the axle box 2 in the direction of the track. The cylindrical housing member 6 has a housing body 60. The housing body 60 is formed in a cylindrical shape overall and is supported by support arms 61 that extend inward from the axle box 2 in the direction of the track. In addition, a support seat 7 is provided on the bottom plate 3B2 of the side beam 3B. The support seat 7 is close to the coil spring 30 in the direction of the track. A receiving member 8 is joined to the side surface 7S1 on the outside in the direction of the sleeper of the support seat 7, and an inner cylinder member 9 is joined to the bottom surface 7S2 of the support seat 7.

[0045] The second cylindrical laminated rubber 50 is coaxially housed in the housing body 60 of the cylindrical housing member 6, in other words, it is positioned on the inside of the axle box 2 in the track direction, and functions as the primary spring of the axle box support device 4. The second cylindrical laminated rubber 50 also has an inner circumferential tube 51, an outer circumferential tube 52, a metal plate 53, and a rubber plate 54. The inner circumferential tube 51, outer circumferential tube 52, metal plate 53, and rubber plate 54 are arranged concentrically. The inner circumferential tube 51 and outer circumferential tube 52 are made of steel and are formed in an annular shape. The metal plate 53 and rubber plate 54 are curved in an arc shape.

[0046] The rubber section 50A, composed of a metal plate 53 and a rubber plate 54, is configured to be elastically deformable and is formed in pairs in a fan shape. In each rubber section 50A, the metal plate 53 is provided in three layers radially between the inner circumferential tube 51 and the outer circumferential tube 52. The circumferential length of each rubber section 50A increases radially outward. The rubber plate 54 is bonded by vulcanization molding between the inner circumferential tube 51 and the inner metal plate 53, between each metal plate 53, and between the outer circumferential tube 52 and the outer metal plate 53. A gap 50B is also formed between the pair of rubber sections 50A.

[0047] A vertically extending support shaft portion 91 formed on the inner cylinder member 9 is coaxially inserted into the inner circumference tube 51 of the second cylindrical laminated rubber 50. The inner circumference tube 51 is fixed to the support shaft portion 91. The outer circumference tube 52 of the second cylindrical laminated rubber 50 is positioned within the housing body 60 by upper and lower C-rings 62 provided at the upper and lower ends inside the housing body 60, so as not to move. The second cylindrical laminated rubber 50 is then press-fitted into the housing body 60 in a compressed state relative to the horizontal direction. Therefore, the housing body 60 is subjected to a radially outward load (pressure force) from the second cylindrical laminated rubber 50.

[0048] Furthermore, the second cylindrical laminated rubber 50 is positioned so that each gap 50B is on the left and right sides (sleeper direction side) of the vehicle 100. Therefore, the second cylindrical laminated rubber 50 mainly receives loads acting in the sleeper direction by deforming in the horizontal direction.

[0049] Next, the behavior of the cylindrical section 21 and the first cylindrical laminated rubber 40 when transitioning from the empty state to the single-unit bogie state will be described. Note that the empty state and the single-unit bogie state refer to the state of the bogie 101 including the cylindrical section 21 and the first cylindrical laminated rubber 40. The empty state is the state of the bogie 101 when the car body 102 supported by the bogie 101 is empty, and the single-unit bogie state is the state of the bogie 101 when the car body 102 has been removed from the bogie 101 and it is a single unit.

[0050] Figures 8A to 8G are explanatory diagrams illustrating the behavior of the cylindrical section 21 and the first cylindrical laminated rubber 40 when transitioning from an empty state to a single bogie state. In the empty state, as shown in Figure 8A, the outer tube 42 of the first cylindrical laminated rubber 40 is held in its normal position and is in contact with the upper locking section 210. From this state, in order to remove the car body 102 from the bogie frame 3, for example, the car body 102 is lifted by a crane or the like with the fixing between the car body 102 and the bogie frame 3 released, and as the load on the bogie frame 3 from the car body 102 gradually decreases, the bogie frame 3 gradually rises and the coil spring 30 extends. As the bogie frame 3 rises, the upper axle spring seat 20 fixed to the bogie frame 3 (side beam 3B) also rises.

[0051] Here, although the outer tube 42 of the first cylindrical laminated rubber 40 is not directly fixed to the cylindrical portion 21 of the upper shaft spring seat 20, the first cylindrical laminated rubber 40 is press-fitted into the cylindrical portion 21 with the outer tube 42 in contact with the inner surface friction reduction portion 21S1, thus pressing the cylindrical portion 21 radially outward. Therefore, as shown in Figure 8B, as the upper shaft spring seat 20 rises, the outer tube 42 is also displaced vertically upward as a whole (rises), and the rubber portion 40A of the first cylindrical laminated rubber 40 undergoes elastic deformation. Then, when the rubber portion 40A of the first cylindrical laminated rubber 40 undergoes elastic deformation, it tries to return to its original state, so the outer tube 42 is pulled downward by the restoring force (a vertically downward tensile force acts on the outer tube 42).

[0052] However, the inner surface friction reduction section 21S1 has a coefficient of friction, and the pressing force of the first cylindrical laminated rubber 40 on the cylindrical section 21 acts as a normal force, so a vertically upward static friction force is generated between the outer tube 42 and the inner surface friction reduction section 21S1. As the vertically upward displacement of the outer tube 42 progresses, the tensile force on the outer tube 42 increases, so the static friction force gradually increases. When the static friction force reaches its maximum static friction force, the vertically upward displacement of the outer tube 42 becomes maximum, as shown in Figure 8C.

[0053] As the car body 102 is further lifted and the bogie frame 3 rises, the outer tube 42 begins to displace (descend) vertically downward, as shown in Figure 8D, and finally, as shown in Figure 8E, it locks into place at the lower locking portion 212, ending the vertical downward displacement of the outer tube 42. Then, as the cylindrical portion 21 rises further, the outer tube 42, which is locked to the lower locking portion 212 of the cylindrical portion 21, displaces vertically upward again, as shown in Figure 8F. Finally, when the car body 102 is completely removed and the rise of the cylindrical portion 21 is finished, the vertical upward displacement (rise) of the outer tube 42 ends, as shown in Figure 8G.

[0054] By the way, in the first embodiment, the coil spring 30 is set to extend by 50 mm when transitioning from an unloaded state to a single-unit bogie state. Also, the allowable value for the vertical displacement of the first cylindrical laminated rubber 40 (outer tube 42) is set to 24 mm. If the vertical displacement of the first cylindrical laminated rubber 40 (outer tube 42) exceeds 24 mm, the first cylindrical laminated rubber 40 will not break (become unusable), but the product life of the first cylindrical laminated rubber 40 will be shortened.

[0055] In the first embodiment, the static friction force reaches its maximum when the vertical upward displacement of the first cylindrical laminated rubber 40 (outer tube 42) is 22 mm. Conversely, the static friction coefficient of the inner surface friction reduction section 21S1 and the fit tolerance (press-fit tolerance) of the first cylindrical laminated rubber 40 with respect to the cylindrical section 21 are set so that the vertical downward tensile force (restoring force) when the outer tube 42 is displaced vertically upward by 22 mm becomes the maximum static friction force.

[0056] The "fit tolerance (press-fit tolerance)" refers to the degree to which the first cylindrical laminated rubber 40 is press-fitted into the cylindrical portion 21. In other words, it is the outer diameter of the first cylindrical laminated rubber 40 when it is not press-fitted into the cylindrical portion 21, relative to the inner diameter of the cylindrical portion 21.

[0057] Furthermore, even if the outer tube 42 is displaced vertically downward after the static friction force between the outer tube 42 and the inner surface friction reduction section 21S1 reaches its maximum static friction force, if the amount of vertical upward displacement (rise) of the outer tube 42 at the time the maximum static friction force is reached exceeds the allowable value, it will cause deterioration of the first cylindrical laminated rubber 40. Therefore, the static friction coefficient of the inner surface friction reduction section 21S1 and the fit tolerance (press-fit tolerance) of the first cylindrical laminated rubber 40 with respect to the cylindrical section 21 are set so that the static friction force between the outer tube 42 and the inner surface friction reduction section 21S1 reaches its maximum static friction force before the amount of vertical upward displacement (rise) of the outer tube 42 reaches the allowable value.

[0058] Furthermore, the amount of vertical upward displacement (rise) of the outer perimeter pipe 42 when the static friction force between the outer perimeter pipe 42 and the inner surface friction reduction section 21S1 reaches the maximum static friction force, in other words, when the outer perimeter pipe 42 begins to displace (descend) vertically downward, is referred to as the "maximum displacement." Therefore, in the first embodiment, the maximum displacement is 22 mm. The maximum displacement of the outer perimeter pipe 42 is at least a value that exceeds the normal maximum displacement of the outer perimeter pipe 42 during operation, specifically, the vertical upward displacement of the outer perimeter pipe 42 when an upward load due to vibrations occurring during running in an unloaded state (in this embodiment, a state where the downward load is 0.6 times the static load in an unloaded state) acts on the bogie frame 3.

[0059] Furthermore, even if the outer tube 42 is displaced (descended) vertically downward after the static friction force between the outer tube 42 and the inner surface friction reduction section 21S1 reaches its maximum static friction force, if the initial value of the displacement suppression gap is not adequately secured, the subsequent upward movement of the cylindrical section 21 will cause the vertical upward displacement of the outer tube 42 to exceed the allowable value. Therefore, in order to prevent the vertical upward displacement of the outer tube 42 from exceeding the allowable value when transitioning from an empty state to a single-unit bogie state, the initial value of the displacement suppression gap is set to be greater than or equal to the value obtained by subtracting the allowable value of the outer tube 42 from the extension amount of the coil spring 30 (50 mm) when transitioning from an empty state to a single-unit bogie state. In the first embodiment, the initial value of the displacement suppression gap is set to 29 mm.

[0060] Thus, in the bogie 101, the inner surface friction reduction portion 21S1 is formed on the inner surface 21S of the cylindrical portion 21, and an appropriate initial value for the displacement suppression gap is secured. As a result, the vertical downward displacement (downward movement) of the outer tube 42 is suppressed until the vertical upward displacement of the outer tube 42 reaches its maximum displacement, and the final vertical upward displacement of the outer tube 42 remains within the allowable value. Therefore, the formation of the inner surface friction reduction portion 21S1 on the inner surface 21S of the cylindrical portion 21, and the appropriate initial value for the displacement suppression gap are referred to as the "downward movement suppression means 4Z1" for keeping the vertical upward displacement of the outer tube 42 within the allowable value. In other words, the axle box support device 4, and by extension the bogie 101, has a downward movement suppression means 4Z1.

[0061] Furthermore, the downward suppression means 4Z1 and the upper locking part 210 suppress the vertical upward displacement (rise) and vertical downward displacement (descendance) of the outer tube 42 until the vertical upward displacement of the outer tube 42 reaches the maximum displacement. Therefore, during normal use (within the range of the normal maximum displacement of the outer tube during operation), the outer tube 42 follows the vertical displacement (rise and fall) of the cylindrical part 21, and the function of the first cylindrical laminated rubber 40 can be maintained. For this reason, the downward suppression means 4Z and the upper locking part 210 together are referred to as the "vertical displacement suppression means 4Z2". In other words, the axle box support device 4, and by extension the bogie 101, has the vertical displacement suppression means 4Z2.

[0062] Here, Figure 9 is a graph showing the relationship between the vertically downward load acting on the bogie frame 3 during the transition from the unloaded state to the bogie-only state in the first embodiment, and the vertically upward displacement of the outer tube 42. In Figure 9, the horizontal axis (X axis) represents the vertically downward load (removed load) removed from the bogie frame 3, and the vertical axis (Y axis) represents the vertically upward displacement of the outer tube 42. Note that the horizontal axis (X axis) and the vertical axis (Y axis) are set to the removed load and displacement in the unloaded state as the origin.

[0063] As shown in Figure 9, initially, the vertical upward displacement of the outer tube 42 increases as the load is reduced. Then, as the vertical upward displacement of the outer tube 42 increases, when the tensile force acting on the outer tube 42 reaches the maximum static friction force, the outer tube 42 displaces vertically downward by the maximum displacement amount to return to the unloaded state, and the vertical downward displacement of the outer tube 42 becomes "0".

[0064] In the first embodiment, the initial value of the displacement suppression gap (29 mm) is longer than the maximum displacement (22 mm). Therefore, when the outer tube 42 is displaced vertically downward by the maximum displacement, there is a small gap (7 mm vertically) between the outer tube 42 and the lower locking part 212. However, in reality, while the outer tube 42 is displaced vertically downward, the cylindrical part 21 rises somewhat, so the gap is absorbed by the rise of the cylindrical part 21. That is, when the outer tube 42 is displaced vertically downward by the maximum displacement, it comes into contact with the lower locking part 212 and is locked. Therefore, the absolute vertical downward displacement of the outer tube 42 is the maximum displacement, but the vertical downward displacement of the outer tube 42 relative to the cylindrical part 21 is equal to the initial value of the displacement suppression gap (29 mm). As a result, when the outer tube 42 contacts the lower locking portion 212, the amount the cylindrical portion 21 rises (the amount the coil spring 30 extends) is 29 mm, and the remaining amount the cylindrical portion 21 rises (the remaining amount the coil spring 30 extends) is 21 mm.

[0065] Then, as the load reduction increases further, the vertical upward displacement of the outer tube 42 also increases again. When the vehicle body 102 is completely removed (remaining as a single bogie) and the load reduction reaches its maximum value, the vertical upward displacement of the outer tube 42 ends. At this point, since the amount the cylindrical part 21 rises (the extension of the coil spring 30) after the outer tube 42 contacts the lower locking part 212 is 21 mm, the final vertical upward displacement of the outer tube 42 is also 21 mm, which is below the allowable value.

[0066] The dashed line graph in Figure 9 shows the relationship between the load removal of the bogie frame 3 and the vertical upward displacement of the outer pipe 42 during the transition from the unloaded state to the bogie-only state, when the outer pipe 42 is constrained to the cylindrical section 21 as shown in Figure 10. When the outer pipe 42 is constrained to the cylindrical section 21 as shown in Figure 10, no static friction force acts between the outer pipe 42 and the cylindrical section 21. However, as the load removal increases, the vertical upward displacement of the outer pipe 42 continues to increase without decreasing. As a result, the vertical upward displacement of the outer pipe 42 exceeds the allowable value.

[0067] Furthermore, in the first embodiment, the static friction coefficient related to the inner surface friction reduction portion 21S1 between the upper locking portion 210 and the lower locking portion 212 on the inner surface 21S of the cylindrical portion 21 is lower than the static friction coefficient related to the rest of the inner surface 21S. The axle box support device 4 is configured such that, for example, if the inner surface friction reduction portion 21S1 is not formed, the static friction force between the cylindrical portion 21 and the outer surface pipe 42 does not reach the maximum static friction force even when the vertical upward displacement of the outer surface pipe 42 reaches the maximum displacement. In other words, the static friction coefficient between the cylindrical portion 21 and the outer surface pipe 42 other than the inner surface friction reduction portion 21S1 ensures that the static friction force between the cylindrical portion 21 and the outer surface pipe 42 does not reach the maximum static friction force even when the vertical upward displacement of the outer surface pipe 42 reaches the allowable value.

[0068] <Second Embodiment> Next, a second embodiment of the present invention will be described. In the following, the differences between the second embodiment and the first embodiment will be mainly described. The same reference numerals and terms will be used for the same configuration as in the first embodiment, or for configurations that correspond similarly.

[0069] The axle box support device 4' according to the second embodiment includes a downward suppression means 4Z1' to prevent the vertical upward displacement of the outer tube 42 from exceeding an allowable value, similar to the downward suppression means 4Z1 in the first embodiment. That is, the downward suppression means 4Z1 and the downward suppression means 4Z1' both have the function of suppressing the vertical upward displacement of the outer tube 42, but they differ in structure. Furthermore, the axle box support device 4' includes a vertical displacement suppression means 4Z2' to suppress the vertical upward displacement (rise) and vertical downward displacement (descendance) of the outer tube 42 until the vertical upward displacement of the outer tube 42 reaches the maximum displacement, similar to the vertical displacement suppression means 4Z2 in the first embodiment. That is, the vertical displacement suppression means 4Z2 and the vertical displacement suppression means 4Z2' both have the function of suppressing the vertical upward displacement (rise) and vertical downward displacement (descendance) of the outer tube 42, but they differ in structure.

[0070] Figure 10 is a front view showing the axle box support device 4' according to the second embodiment. In Figure 10, a portion is shown in cross-section. As shown in Figure 10, in the second embodiment, similar to the first embodiment, the cylindrical portion 21 has an upper locking portion 210, a sliding portion 211, and a lower locking portion 212. However, an inner surface friction reduction portion 21S1 as a downward suppression means 4Z1 is not provided between the upper locking portion 210 and the lower locking portion 212. Instead of the inner surface friction reduction portion 21S1, four special breaking members 25 with a rectangular vertical cross-sectional shape are arranged between the outer circumferential pipe 42 and the lower locking portion 212. The plan view shape of the special breaking members 25 is an arc shape with a central angle of 60 degrees. Each special breaking member 25 is arranged at equal intervals in the circumferential direction.

[0071] The outer surface of each special breaking member 25 is in contact with the space between the upper locking portion 210 and the lower locking portion 212 of the cylindrical portion 21. As in the first embodiment, the first cylindrical laminated rubber 40 is press-fitted into the cylindrical portion 21 of the upper shaft spring seat 20 in a compressed state relative to the horizontal direction, or in other words, in the radial direction relative to the spring centerline O1. Therefore, the cylindrical portion 21 of the upper shaft spring seat 20 receives a radially outward load (compression force) from the first cylindrical laminated rubber 40.

[0072] The upper surface of each special breaking member 25 abuts against the outer tube 42, and the lower surface of each special breaking member 25 abuts against the lower locking portion 212. Therefore, the outer tube 42 is sandwiched in the vertical direction between the upper locking portion 210 and the lower locking portion 212 via the special breaking member 25, and is restrained in the vertical direction with respect to the cylindrical portion 21. As a result, similar to the first embodiment, as the trolley frame 3 rises due to an increase in the load relief on the trolley frame 3, the outer tube 42 is displaced (risen) vertically upward.

[0073] Furthermore, a special breaking member 25 is sandwiched between the outer perimeter pipe 42 and the lower locking portion 212, but the initial value of the displacement suppression gap is set to the same value as in the first embodiment. Also, the special breaking member 25 is fixed to the lower locking portion 212. That is, the special breaking member 25 is supported by the lower locking portion 212 from below.

[0074] Furthermore, the special failure member 25 is made of a material that will collapse when a load exceeding a certain amount is applied. Specifically, the special failure member 25 is made of a material that will be crushed and destroyed by the tensile force on the outer tube 42 (restoring force of the first cylindrical laminated rubber 40) that occurs when the vertical displacement of the outer tube 42 reaches the maximum displacement in the first embodiment, by being crushed between the outer tube 42 and the lower locking part 212. Therefore, when the tensile force on the outer tube 42 reaches the maximum tensile force, the special failure member 25 is destroyed, and at that time the outer tube 42 is displaced (descended) vertically downward and locked to the lower locking part 212.

[0075] Thus, in the second embodiment as well, the outer tube 42 rises together with the cylindrical portion 21, but when the vertical upward displacement of the outer tube 42 reaches its maximum displacement, it temporarily displaces vertically downward (descends), so the final vertical upward displacement (rise) of the outer tube 42 is kept smaller than the final vertical upward displacement (rise) of the cylindrical portion 21.

[0076] Furthermore, in the second embodiment, multiple (four in the second embodiment) special destruction members 25 are arranged at equal intervals in the circumferential direction. That is, gaps are formed between adjacent special destruction members 25 in the circumferential direction. Therefore, when a special destruction member 25 is destroyed, the material of the special destruction member 25 is easily drawn into these gaps. As a result, even if some remnants of the special destruction member 25 remain, the amount of vertical downward displacement (downward movement) of the outer perimeter pipe 42 is substantially equal to the initial value of the displacement suppression gap.

[0077] Furthermore, although the initial value of the displacement suppression gap is greater than the maximum displacement, the cylindrical portion 21 rises while the outer tube 42 is displaced vertically downward, so the absolute vertical upward displacement (rise) of the outer tube 42 when the special breaking member 25 is destroyed is "0". After the special breaking member 25 is destroyed, as in the first embodiment, the outer tube 42 rises together with the cylindrical portion 21 while locked to the lower locking portion 212, as the bogie frame 3 rises due to the increase in the load relief on the bogie frame 3. The vertical upward displacement of the outer tube 42 ends before the displacement (rise) reaches the allowable value when the bogie becomes a standalone unit.

[0078] Furthermore, in the second embodiment, although not shown, a lubricant is applied between the outer tube 42 and the cylindrical portion 21, and before the special breaking member 25 is broken, almost no frictional force is generated between the outer tube 42 and the cylindrical portion 21. Therefore, the tensile force generated in the outer tube 42, which is displaced (moves upward) vertically while fixed between the special breaking member 25 and the upper locking portion 210, acts almost directly on the special breaking member 25.

[0079] Thus, in the trolley 101' according to the second embodiment, the special breaking member 25 is supported from below by the lower locking portion 212, the special breaking member 25 is sandwiched between the outer perimeter pipe 42 and the lower locking portion 212, an initial value for the displacement suppression gap is secured, and the special breaking member 25 is made of a material that will collapse when a load exceeding a certain amount is applied, so that the amount of vertical upward displacement of the outer perimeter pipe 42 is kept within the allowable value. Therefore, the fact that the special breaking member 25 is supported from below by the lower locking portion 212, the special breaking member 25 is sandwiched between the outer perimeter pipe 42 and the lower locking portion 212, an initial value for the displacement suppression gap is secured, and the special breaking member 25 is made of a material that will collapse when a load exceeding a certain amount is applied, is referred to as the "downward suppression means 4Z1'" for keeping the amount of vertical upward displacement of the outer perimeter pipe 42 within the allowable value. In other words, the axle box support device 4', and by extension the bogie 101', has a downward suppression means 4Z1'. Furthermore, the downward suppression means 4Z1' and the upper locking part 210 suppress the vertical upward displacement (rise) and vertical downward displacement (descendance) of the outer perimeter pipe 42 until the vertical upward displacement of the outer perimeter pipe 42 reaches its maximum displacement. Therefore, the downward suppression means 4Z1' and the upper locking part 210 together are referred to as the "vertical displacement suppression means 4Z2'". In other words, the axle box support device 4', and by extension the bogie 101', has a vertical displacement suppression means 4Z2'.

[0080] As described above, the axle box support device 4,4' comprises a coil spring 30 interposed between the bogie frame 3 and the axle box 2, which are included in the bogies 101,101' that support the car body 102, and which is expandable and contractible in the vertical direction, and a first cylindrical laminated rubber 40 interposed between the upper axle spring seat 20 on the bogie frame 3 side to which the coil spring 30 is fixed and the lower axle spring seat 10 on the axle box 2 side, and which is arranged concentrically. The axle box 2 is elastically supported by the bogie frame 3 by the coil spring 30 and the first cylindrical laminated rubber 40, the upper axle spring seat 20 has a cylindrical portion 21 that is open at the bottom, and the first cylindrical laminated rubber 40 has an outer peripheral tube 42 that is positioned on the outermost side, and the outer peripheral tube 42 is press-fitted radially into the cylindrical portion 21 with the outer peripheral tube 42 in contact with the cylindrical portion 21. The cylindrical portion 21 can be raised as the coil spring 30 extends during the transition from an empty state with the car body 102 to a state where the bogies 101 and 101' do not support the car body 102. The vehicle is equipped with vertical displacement suppression means 4Z2 and 4Z2' to suppress the vertical displacement of the outer tube 42 relative to the cylindrical portion 21. The vertical displacement suppression means 4Z2 and 4Z2' are configured to release the suppression of the vertical downward displacement of the outer tube 42 relative to the cylindrical portion 21 when the vertical downward tensile force on the outer tube 42 by the first cylindrical laminated rubber 40 due to the vertical upward displacement of the outer tube 42 reaches a predetermined value. The amount of vertical upward displacement of the outer tube 42 when the tensile force reaches a predetermined value is less than a preset value. The outer tube 42 is firmly fixed to the cylindrical portion 21 by the vertical displacement suppression means 4Z2 and 4Z2' until the tensile force reaches a predetermined value. Therefore, during normal use (within the range of the normal maximum displacement of the outer tube during operation), the outer tube 42 follows the vertical displacement (up and down) of the cylindrical section 21, and the function of the first cylindrical laminated rubber 40 can be maintained. However, if the suppression of the vertical displacement of the outer tube 42 relative to the cylindrical section 21 is not released during the transition from the empty state to the single-unit bogie state, the outer tube 42 will continue to displace vertically upward, and when transitioning from the empty state to the single-unit bogie state, the amount of vertical upward displacement of the outer tube 42 will exceed the allowable value.However, the vertical displacement suppression means 4Z2, 4Z2' release the suppression of the vertical downward displacement of the outer tube 42 relative to the cylindrical portion 21 when the vertical downward tensile force on the outer tube 42 by the first cylindrical laminated rubber 40 due to the vertical upward displacement of the outer tube 42 reaches a predetermined value, in other words, during the transition from the unloaded state to the trolley-only state, so that the outer tube 42 is displaced vertically downward. As a result, the final amount of vertical upward displacement of the outer tube 42 can be reduced.

[0081] Furthermore, according to the axle box support devices 4,4', a lower locking portion 212 is formed on the inner surface 21S of the cylindrical portion 21, below the outer tube 42, projecting radially inward. The value obtained by subtracting the distance from the lower end of the outer tube 42 to the upper surface of the locking portion (initial displacement suppression gap value: 29 mm) from the amount of extension of the coil spring 30 from the unloaded state to the bogie-only state (50 mm) is less than the specified value (24 mm). When the cylindrical portion 21 rises further after the tensile force reaches a predetermined value, the outer tube 42 is locked by the lower locking portion 212. Therefore, it is possible to prevent the first cylindrical laminated rubber 40 from coming off the upper axle spring seat 20. Moreover, when the cylindrical portion 21 rises further after the tensile force reaches a predetermined value, it is possible to prevent the vertical upward displacement of the outer tube 42 from exceeding the specified value.

[0082] Furthermore, according to the axle box support devices 4,4', the predetermined value is less than 0.6 times the weight of the vehicle body in an unloaded state. Therefore, during normal use (within the range of the normal maximum displacement of the outer tube during operation), it is possible to prevent the outer tube 42 from being displaced vertically downward relative to the cylindrical section 21, thereby preventing a decrease in the function of the first cylindrical laminated rubber 40.

[0083] Furthermore, according to the axle box support device 4, as a vertical displacement suppression means 4Z2, an inner surface friction reduction portion 21S1 is provided on the inner surface 21S of the cylindrical portion 21 that is in contact with the outer tube 42, such that the maximum static friction force is a predetermined value. Therefore, the final vertical upward displacement of the outer tube 42 can be reduced while suppressing an increase in the number of parts. On the other hand, according to the axle box support device 4', a lower locking portion 212 that protrudes radially inward is formed on the inner surface 21S of the cylindrical portion 21 below the outer tube 42, and as a vertical displacement suppression means 4Z2', a special breaking member 25 made of a material that breaks when the tensile force (compressive force on the special breaking member 25) of the first cylindrical laminated rubber 40 reaches a predetermined value is provided between the lower locking portion 212 and the outer tube 42. Therefore, the final vertical upward displacement of the outer tube 42 can be reduced while more reliably fixing the outer tube 42 to the cylindrical portion 21 until the tensile force reaches a predetermined value.

[0084] (modified version) The present invention has been described above based on the first and second embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in the combination of these components, and that such modifications also fall within the scope of the present invention.

[0085] In the first embodiment, when the vertical upward displacement of the outer tube 42 reaches its maximum displacement and the outer tube 42 is displaced vertically downward, the outer tube 42 locks into the lower locking portion 212, and thereafter, while locked, it is displaced vertically upward again. However, the lower locking portion 212 may be omitted. In this case, when the outer tube 42 is displaced vertically downward and the vertical upward displacement of the outer tube 42 becomes "0", the tensile force acting on the outer tube 42 also ceases. Therefore, in response to the subsequent upward movement of the cylindrical portion 21, the outer tube 42 may be displaced vertically upward together with the cylindrical portion 21 due to the static friction force between it and the inner surface friction reduction portion 21S1.

[0086] In the second embodiment, four special destruction members 25 are arranged at equal intervals along the circumferential direction, but the number of special destruction members 25 may be more than four. Furthermore, the length of the gaps between the special destruction members 25 does not have to be equal. Alternatively, one special destruction member 25 formed in a circular shape in plan view may be arranged. In this case, it is preferable to have multiple special destruction members 25 and gaps formed between them, in order to remove the remnants of the special destruction members 25 from the gaps. On the other hand, in terms of ease of initial installation and replacement after destruction, it is preferable to have one special destruction member 25, in order to remove the remnants from the gaps.

[0087] In the second embodiment, a lubricant is applied between the outer tube 42 and the cylindrical portion 21, but it is also possible to omit the application of a lubricant. If the coefficient of static friction between the outer tube 42 and the cylindrical portion 21 is high and the static friction force between the outer tube 42 and the cylindrical portion 21 prevents the outer tube 42 from being pulled vertically downward and destroying the special destruction member 25, then a surface treatment may be applied between the upper locking portion 210 and the lower locking portion 212 of the inner surface 21S of the cylindrical portion 21, such as an inner surface friction reduction portion 21S1, to reduce the static friction force to a level lower than the static friction force between the outer tube 42 and the cylindrical portion 21. That is, the vertical displacement suppression means 4Z2' and the vertical displacement suppression means 4Z2 may be combined. However, in this case, the static friction force of the inner surface friction reduction portion 21S1 will be lower due to the presence of the special destruction member 25 between the outer tube 42 and the lower locking portion 212.

[0088] The amount of extension of the coil spring 30, the displacement suppression distance L1, and the allowable displacement of the outer tube 42 when transitioning from an empty state to a single-tube state may be appropriately set within a range that satisfies the condition that the displacement suppression distance L1 is greater than the amount of extension of the coil spring 30 when transitioning from an empty state to a single-tube state minus the allowable displacement of the outer tube 42.

[0089] The structures of the bogie frame 3, the lower axle spring seat 10, the upper axle spring seat 20, the coil spring 30, the first cylindrical laminated rubber 40, and the second cylindrical laminated rubber 50 are not limited to the first embodiment and may be modified as appropriate. Also, although a tandem type axle box support device is illustrated in this embodiment, the structure is not limited to this. Any structure in which the bogie frame is supported by a coil spring and cylindrical laminated rubber provided on the axle box is acceptable. [Explanation of Symbols]

[0090] 100...vehicle, 101...bogie, 102...car body 1...Wheelset, 2...Axle box, 3...Bogie frame, 4,4'...Axle box support device, 4Z1,4Z1'...Downward suppression means, 4Z2,4Z2'...Vertical displacement suppression means 10...Lower shaft spring seat, 20...Upper shaft spring seat, 30...Coil spring, 40...First cylindrical laminated rubber, 50...Second cylindrical laminated rubber 11...Support shaft portion, 21...Cylindrical portion, 21S...Inner surface, 21S1... 210...Upper locking part, 211...Sliding part, 212...Lower locking part 41...Inner tube, 42...Outer tube, 43...Metal plate, 44...Rubber plate, 40A...Rubber part, 40B...Gap L1…Displacement suppression gap, O1…Spring centerline

Claims

1. A railway vehicle axle box support device comprising a coil spring interposed between a bogie frame and an axle box, which are included in a bogie that supports the vehicle body, and which is expandable and contractible in the vertical direction, and a cylindrical laminated rubber interposed between a member on the bogie frame side to which the coil spring is fixed and a member on the axle box side, which is arranged concentrically, wherein the axle box is elastically supported on the bogie frame by the coil spring and the cylindrical laminated rubber, The member on the bogie frame side has a cylindrical portion that is open at the bottom, The cylindrical laminated rubber has an outer peripheral tube positioned on the outermost side, and the outer peripheral tube is press-fitted radially into the cylindrical portion with the cylindrical portion in contact with the cylindrical portion. The cylindrical portion can be raised as the coil spring extends during the transition from an empty state with the car body to a state where the bogie does not support the car body. The outer tube is equipped with a displacement suppression means for suppressing vertical displacement of the outer tube relative to the cylindrical portion, The displacement suppression means is configured such that when the vertical downward tensile force on the outer tube by the cylindrical laminated rubber due to the vertical upward displacement of the outer tube reaches a predetermined value, the suppression of the vertical downward displacement of the outer tube relative to the cylindrical portion is released. A railway vehicle axle box support device characterized in that the amount of vertical upward displacement of the outer tube when the tensile force reaches the predetermined value is less than a preset value.

2. A railway vehicle axle box support device according to claim 1, A locking portion is formed on the inner surface of the cylindrical portion, below the outer periphery of the tube, projecting radially inward. A railway vehicle axle box support device characterized in that the value obtained by subtracting the distance from the outer tube to the locking portion from the amount of extension of the coil spring from the empty state to the bogie-only state is less than the specified value.

3. A railway vehicle axle box support device according to claim 1, The axle box support device for railway vehicles is characterized in that, as the displacement suppression means, the inner surface of the cylindrical portion that is in contact with the outer periphery tube is subjected to a surface treatment such that the maximum static friction force becomes the predetermined value.

4. A railway vehicle axle box support device according to claim 1, A locking portion is formed on the inner surface of the cylindrical portion, below the outer periphery of the tube, projecting radially inward. A railway vehicle axle box support device characterized in that, as the displacement suppression means, a special member made of a material that breaks when the tensile force reaches the predetermined value is provided between the locking portion and the outer periphery tube.

5. A bogie equipped with a railway vehicle axle box support device according to any one of claims 1 to 4.

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