Rubber bushing for railway bogie

Abstract

A rubber bushing for a railway bogie with a new structure is realized, which can achieve an improvement in flame retardancy and the like against flames and the like spreading from the outside without significantly impairing the basic characteristics required for the input vibration and load. The rubber bushing 10 used in the bogie of a railway vehicle is formed by connecting a shaft-shaped inner member 12 and an outer member 14 separately disposed on the outer peripheral side of the inner member 12 with a rubber elastic body 16. At the axial end of the rubber elastic body 16, a covering portion 48 is provided by a member independent of the rubber elastic body 16, and the covering portion 48 covers, from the outside, an end exposed surface 44 of the rubber elastic body 16 that is exposed between the axial ends of the inner member 12 and the outer member 14 and is exposed to the outside.

Description

Technical Field

[0001] The present invention relates to a rubber bushing for a railway bogie for a bogie of a railway vehicle. Background Art

[0002] Conventionally, in a bogie of a railway vehicle, in an axle box support device and a car body support device, a rubber bushing is used as one of the buffer mechanisms in a connecting portion of a structural member. The axle box support device is a device that connects a wheel axle (a member that combines a wheel and an axle) and a bogie frame via a buffer mechanism. For example, a single link type axle box support device that connects a bogie frame and a wheel axle with a single link, and an axle beam type axle box support device that connects the front end of an axle beam extending from an axle box formed integrally with the axle box to a bogie frame are known. The car body support device is a device that connects a bogie frame to a car body via a buffer mechanism. For example, a traction device that connects a traction frame on the car body side and a bogie frame with a traction link in a non-crossbeam bogie is known.

[0003] Incidentally, a bogie for a railway vehicle is a traveling device that supports the load of a railway car body and allows the railway car body to travel, and is used in a state where it is exposed below the railway car body. Therefore, for example, when an external fire or the like occurs, it is conceivable that a flame and heat directly reach the bogie from below or the side.

[0004] However, in a bogie for a railway vehicle, not only the bogie frame is made of metal, but also wheels, axles, axle boxes, braking devices, etc., especially most of the components constituting the lower part of the bogie are made of metal. Therefore, it is considered that there is no great risk with respect to external flames, high heat, etc.

[0005] However, as shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-168397) and the like, in recent years, in the above-mentioned axle box support device, as a buffer mechanism between a wheel axle and a bogie frame, in addition to a coil spring, a rubber bushing is mostly used. In a traction device, as shown in Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-249042) and the like, both ends of a traction link are connected to a traction frame and a bogie frame via rubber bushings.

[0006] This rubber bushing is generally assembled at a position relatively lower (below the bogie frame) of a bogie for a railway vehicle, and thus there is a concern about problems such as combustion, smoking, or generation of toxic gases when it is affected by a flame or high heat from the outside of the bogie for a railway vehicle.

[0007] It should be noted that in view of such problems, special materials with relatively high flame retardancy have also been studied as the rubber material of the rubber bushing, but it is difficult to take into account the basic characteristics such as the vibration prevention and damping performance, load resistance performance, and durability performance required for the rubber bushing.

[0008] In addition, as the rubber surface layer of the rubber bushing, a flame-retardant coating has also been studied to be provided integrally. However, there is a hidden danger that the coating fixedly connected or integrally formed on the rubber surface hinders the free deformation of the rubber surface. Moreover, since the rubber surface repeatedly elastically deforms due to the input under the assembled state, there is also a problem that the coating is likely to crack and it is difficult to maintain the coating effect as the purpose stably for a long time.

[0009] Prior art documents

[0010] Patent documents

[0011] Patent document 1: Japanese Patent Application Laid-Open No. 2015-168397

[0012] Patent document 2: Japanese Patent Application Laid-Open No. 2002-249042 Summary of the invention

[0013] Problems to be solved by the invention

[0014] The present invention has been completed against the above background, and its object is to provide a rubber bushing for a railway bogie with a novel structure, which can improve the flame retardancy and the like against flames and the like spreading from the outside without significantly impairing the required basic characteristics.

[0015] Means for solving the problems

[0016] Hereinafter, preferred modes for understanding the present invention will be described. However, each of the modes described below is an exemplary description, and not only can they be appropriately combined and used, but for the multiple constituent elements described in each mode, they can also be identified and used as independently as possible, and can also be appropriately combined with any of the constituent elements described in other modes and used. Thus, in the present invention, it is not limited to the modes described below, and various other modes can be realized.

[0017] The first mode is a rubber bushing for a railway bogie, which is formed by connecting a shaft-shaped inner member and an outer member arranged to be separated on the outer peripheral side of the inner member by a rubber elastic body, and is a rubber bushing used in the bogie of a railway vehicle. Among them, at the axial end of the rubber elastic body, a covering portion is provided by a member independent of the rubber elastic body, and the covering portion covers the end exposed surface of the rubber elastic body exposed to the outside between the axial ends of the inner member and the outer member from the outside.

[0018] In the rubber bushing for a railway bogie of this embodiment (hereinafter, also simply referred to as the rubber bushing), the exposed surface of the end portion of the rubber elastomer is covered by a covering portion composed of a member independent of the rubber elastomer. Therefore, even when a flame or the like spreads from the outside to a railway vehicle bogie (hereinafter, also simply referred to as the bogie) equipped with the rubber bushing, it is possible to reduce or avoid the exposed surface of the rubber elastomer being directly exposed to the flame or the like. Moreover, since the covering portion is provided as an independent member, the degree of freedom in selecting the material of the rubber elastomer is not restricted, and it is also possible to avoid the characteristics of the rubber elastomer itself being significantly hindered by the covering portion.

[0019] In the second embodiment, in the rubber bushing for a railway bogie according to the first embodiment, a large-diameter brim-shaped rubber portion is provided at the axial end of the rubber elastomer. The brim-shaped rubber portion is axially sandwiched between the axial ends of the inner member and the outer member, and the outer peripheral surface of the brim-shaped rubber portion is formed as the exposed surface of the end portion and is covered by the covering portion.

[0020] The rubber bushing for a railway bogie of this embodiment can be preferably used, for example, as a rubber bushing assembled in an installation portion on the side of the bogie frame at the front end of the axle beam in an axle beam type axle box support device. In particular, in a rubber bushing having a brim-shaped rubber portion as in this embodiment, a large spring constant and large load resistance can be obtained in the axial direction. On the other hand, since the brim-shaped rubber portion is exposed toward the outer peripheral surface of the rubber bushing, there is a case where the flame retardancy against a flame from below the bogie is likely to become a problem. To solve this problem, in this embodiment, by covering the exposed surface of the brim-shaped rubber portion facing the outer peripheral surface, it is possible to reduce the risk against a flame or the like from the outside while ensuring the basic elastic characteristics and the like.

[0021] In the third embodiment, based on the rubber bushing for a railway bogie according to the first embodiment, the axial end of the rubber elastomer has an axially exposed surface that is exposed axially outward between the axial ends of the inner member and the outer member. The axially exposed surface is formed as the exposed surface of the end portion and is covered by the covering portion.

[0022] The rubber bushing for a railway bogie of this method can be preferably used, for example, as a rubber bushing assembled in the mounting portions on the bogie frame side and the axle side of a single link in a single link type axle box support device. In particular, in a rubber bushing like this method, the spring ratio in the axial direction perpendicular to the axis can be set relatively large. On the other hand, the axial end portions of the rubber bushing are exposed to the outside in the axial direction over a relatively large area. Therefore, there are cases where problems such as flame retardancy against flames from the side of the bogie are likely to occur. To address this problem, in this method, by covering the exposed surface of the rubber elastomer facing the outside in the axial direction, it is possible to reduce the risk against flames from the outside while ensuring basic elastic characteristics and the like.

[0023] The fourth method is based on the rubber bushing for a railway bogie according to any one of the first to third methods, and a gap is provided between the exposed surface of the end portion of the rubber elastomer and the covering portion.

[0024] In the rubber bushing for a railway bogie of this method, by the gap provided between the exposed surface of the end portion of the rubber elastomer and the covering portion, it is possible to reduce or avoid the deformation constraint of the free surface of the rubber elastomer by the covering portion. In addition, the heat transfer from the covering portion to the rubber elastomer can be suppressed by the air layer of the gap. In addition, it is possible to reduce or avoid wear, damage, etc. caused by the contact between the exposed surface of the end portion with elastic deformation and the covering portion. It should be noted that it is not necessary to provide a gap throughout the entire area between the exposed surface of the end portion of the rubber elastomer and the covering portion.

[0025] The fifth method is based on the rubber bushing for a railway bogie according to any one of the first to fourth methods, and at least a part of the covering portion is in contact with the exposed surface of the end portion of the rubber elastomer.

[0026] In the rubber bushing for a railway bogie of this method, the exposed surface of the end portion of the rubber elastomer is in contact with the covering portion, so that it is easy to maintain the state where the exposed surface of the end portion is covered by the covering portion. In addition, by bringing the covering portion into contact with the rubber elastomer, the positioning of the covering portion in the assembled state becomes easy. In addition, by making the covering portion closely adhere to the exposed surface of the end portion, the supply of air is blocked at least in the contact portion, and it is easy to suppress the combustion of the rubber elastomer.

[0027] The sixth method is based on the rubber bushing for a railway bogie according to any one of the first to fifth methods, and at least a part of the covering portion is formed of a highly elastic body.

[0028] In the rubber bushing for a railway bogie of this embodiment, based on the deformable characteristics of the high elastic body, for example, even when it is assumed that the covering portion contacts the end exposed surface, the deformation constraint force on the rubber elastomer can be reduced, so that the characteristics of the rubber elastomer can be ensured well. In addition, for example, as in the seventh embodiment described later, by utilizing the elastic characteristics of the high elastic body, it is also possible to easily hold the covering portion in the assembled state or perform positioning, etc. In addition, due to the deformable characteristics of the high elastic body, for example, it is also possible to reduce or avoid damage to components in the case where it is assumed that the covering portion contacts the end exposed surface, etc.

[0029] In the seventh embodiment, based on the rubber bushing for a railway bogie according to the sixth embodiment, the covering portion is positioned at a position covering the end exposed surface of the rubber elastomer from the outside by using the elasticity of the high elastic body.

[0030] In the rubber bushing for a railway bogie of this embodiment, the characteristics of the high elastic body constituting the covering portion can be skillfully utilized to simplify the assembly structure of the covering portion, improve the stability of the assembled state, etc.

[0031] In the eighth embodiment, based on the rubber bushing for a railway bogie according to any one of the first to seventh embodiments, in the assembled state where the rubber bushing for a railway bogie is assembled to the bogie of the railway vehicle, the end exposed surface of the rubber elastomer is covered by the covering portion in a state where it cannot be directly visually observed from the outside in any direction.

[0032] In the rubber bushing for a railway bogie of this embodiment, effective resistance to flames and heat spreading not only from a specific direction but also from various directions can be imparted to the rubber elastomer. Therefore, it is also possible to achieve responses such as ensuring flame retardancy in unexpected situations, and it is also easy to respond while maintaining flame retardancy, etc. when changing the assembled state, orientation, position, etc.

[0033] Advantages of the Invention

[0034] According to the present invention, it is possible to realize a rubber bushing for a railway bogie with a new structure, which can improve flame retardancy, etc. against flames, etc. spread from the outside without significantly impairing the basic characteristics required for the input vibration and load. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a front view showing a rubber bushing for an axle box support device as a first embodiment of the present invention.

[0036] Figure 2 is Figure 1 the left view of.

[0037] Figure 3 isFigure 2 The III-III sectional view.

[0038] Figure 4 is Figure 3 The IV-IV sectional view.

[0039] Figure 5 is Figure 3 The V-V sectional view.

[0040] Figure 6 In (a), it is a single-piece drawing of the covering ring that forms the rubber bushing for the axle box support device shown in Figure 1 axial outer surface view, and (b) is the VI-VI sectional view of (a).

[0041] Figure 7 It shows Figure 1 an explanatory drawing of the assembled state where the rubber bushing for the axle box support device shown is assembled to the bogie for railway vehicles.

[0042] Figure 8 It is the front view showing the rubber bushing for the axle box support device as the second embodiment of the present invention.

[0043] Figure 9 is Figure 8 The left view.

[0044] Figure 10 is Figure 9 The X-X sectional view.

[0045] Figure 11 In (a), it is a single-piece drawing of the covering cover that forms the rubber bushing for the axle box support device shown in Figure 8 axial inner surface view, and (b) is the XI-XI sectional view of (a).

[0046] Figure 12 It shows Figure 8 an explanatory drawing of the assembled state where the rubber bushing for the axle box support device shown is assembled to the bogie for railway vehicles. Detailed implementation mode

[0047] Hereinafter, embodiments exemplarily showing the implementation levels to which the present invention is applied will be described with reference to the drawings.

[0048] In Figures 1 to 6 , as the first embodiment of the rubber bushing for railway bogies formed in accordance with the structure of the present invention, that is, the rubber bushing for the axle box support device, the rubber bushing 10 for the axle beam is shown, and the rubber bushing 10 for the axle beam is assembled to the mounting portion of the axle beam to be mounted on the bogie for railway vehicles.

[0049] The rubber bushing 10 for the axle beam of the present embodiment is integrally formed into a substantially cylindrical bushing structure, and includes an inner member 12 as an inner member and an outer member 14 as an outer member that is separably disposed on its outer periphery. Further, the inner member 12 and the outer member 14 are elastically connected by a rubber elastomer 16. It should be noted that in the following description, the axial direction refers to the central axis direction of the rubber bushing 10 and the inner member 12, and the axis perpendicular direction refers to the direction orthogonal to the central axis of the rubber bushing 10 and the inner member 12.

[0050] More specifically, the inner member 12 is a highly rigid member formed of a metal such as iron or aluminum alloy, and has a rod shape that is hollow or solid and extends linearly. It should be noted that in the present embodiment, it is formed into a hollow substantially cylindrical shape provided with a central hole 18 penetrating in the axial direction.

[0051] The central portion in the axial direction of the inner member 12 is formed into a central rod portion 20 that extends in a constant cylindrical shape. At both axial ends of the central rod portion 20, a pair of inner flange-like portions 22, 22 that project outward in a flange shape are integrally formed.

[0052] It should be noted that the outer surface in the axial direction of the inner flange-like portion 22 is formed into a flat surface that expands in the axis perpendicular direction. On the other hand, the inner surface in the axial direction is formed into an inclined surface that smoothly rises in such a way that the inclination angle gradually increases from the cylindrical outer peripheral surface of the central rod portion 20 toward the outside in the axial direction. Thus, in the inner peripheral portion of the inner flange-like portion 22, the axial thickness dimension gradually decreases toward the outside in the axial direction.

[0053] In addition, both axial end portions of the inner member 12 are formed into inner shaft end portions 24, 24 that project outward in the axial direction with a substantially polygonal outer peripheral surface shape. In the inner shaft end portions 24, 24, through holes 26, 26 for installation are formed so as to penetrate in the axis perpendicular direction.

[0054] On the other hand, the above-described outer member 14 is composed of a pair of outer split bodies 28, 28. Each outer split body 28 has a central plate-like portion 30 having an arc-shaped curved plate shape that extends in the circumferential direction with a length less than half a circumference (in the present embodiment, approximately 1 / 4 circumference). In addition, at both axial ends of the central plate-like portion 30, outer flange-like portions 32 that are expanded in diameter toward the outside in the axial direction by being bent outward are integrally formed. It should be noted that the outer split body 28 constituting the outer member 14 of the present embodiment can be manufactured, for example, by stamping a metal plate.

[0055] Moreover, a pair of outer split bodies 28, 28 are disposed separately on the outer peripheral side of the central rod portion 20 of the inner member 12, and are disposed at opposed positions while clamping the inner member 12 in one direction in the axis vertical direction. In this disposed state, the central rod portion 20 of the inner member 12 and the central plate-like portions 30, 30 of the outer split bodies 28, 28 are opposed to each other in the axis vertical direction with a substantially constant distance between the opposed surfaces, and the inner brim-like portions 22 of the inner member 12 and the outer brim-like portions 32, 32 of the outer split bodies 28, 28 are opposed to each other in the axis inclined direction with a substantially constant distance between the opposed surfaces. However, the shapes, dimensions, etc. of the inner member 12, the outer split bodies 28, 28, and the rubber elastic body 16 are appropriately set according to the required characteristics and are not limited. For example, the thickness of the opposed surfaces between the inner brim-like portion 22 and the outer brim-like portion 32 and the thickness of the brim-like rubber portion 36 described later are formed into a shape that tapers toward the front end, or the inclination angle of the brim-like rubber portion 36 is changed, or the circumferential length of the outer split body 28 is changed, or the axial lengths of the outer split body 28 and the rubber elastic body 16 are changed, whereby the required characteristics, etc. can be appropriately dealt with.

[0056] Furthermore, the above-mentioned rubber elastic body 16 has a generally thick-walled cylindrical shape as a whole. The central portion in the axial direction is formed into a central cylindrical portion 34 having a straight cylindrical shape. The both side portions in the axial direction are formed into brim-like rubber portions 36, 36 that expand from both sides in the axial direction of the central cylindrical portion 34 toward the outer peripheral side. The central cylindrical portion 34 and the pair of brim-like rubber portions 36, 36 are continuous with a substantially constant thickness dimension. It should be noted that, as described above, the thickness dimension, inclination angle, etc. of the brim-like rubber portion 36 can be appropriately designed and changed. In addition, the central cylindrical portion 34 and the brim-like rubber portion 36 can be set as independent members. For example, the central cylindrical portion 34 and the brim-like rubber portion 36 can be set to different materials. It should be noted that, in the inner member 12 and the outer member 14, the inner brim-like portion 22 and the outer brim-like portion 32 can also be assembled as independent members.

[0057] Furthermore, a central cylindrical portion 34 is arranged on the outer peripheral surface of the central rod portion 20 of the inner member 12, and brim-shaped rubber portions 36, 36 are arranged on the axial inner surfaces of the inner brim-shaped portions 22, 22 of the inner member 12. That is, the rubber elastic body 16 is fixed to the outer peripheral surface of the inner member 12 in a manner that it continuously and closely covers substantially the entire surface from the outer peripheral surface of the central rod portion 20 of the inner member 12 to the axial inner surfaces of the inner brim-shaped portions 22, 22. It should be noted that the inner member 12 covered with the inner peripheral surface of the rubber elastic body 16 does not need to be continuous over the entire surface. For example, when the central cylindrical portion 34 and the brim-shaped rubber portion 36 of the rubber elastic body 16 are independent components as described above, the fixed surface fixed to the inner member 12 may be separated. For example, when a hollow portion (a concave portion, etc.) is locally provided in the rubber elastic body for the purpose of adjusting spring characteristics, etc., the inner peripheral surface of the rubber elastic body 16 that is not covered by the inner member 12 may exist.

[0058] In addition, on the outer peripheral surface of the rubber elastic body 16, in one radial direction ( Figure 3 , Figure 4 The pair of outer split bodies 28, 28 overlap in the portions facing each other in the vertical direction (in the vertical direction). The central plate-shaped portion 30 of each outer split body 28 overlaps with the outer peripheral surface of the central cylindrical portion 34, and the outer brim-shaped portions 32, 32 of each outer split body 28 overlap with the axial inner surface of the brim-shaped rubber portions 36, 36. That is, the pair of outer split bodies 28, 28 are fixed to the outer peripheral surface of the rubber elastic body 16 in such a manner that the portions facing each other in one radial direction respectively closely cover the outer peripheral surface of the rubber elastic body 16.

[0059] It should be noted that in the radial direction ( Figure 4 The left and right directions in Figure 5 In the two side portions (in the vertical direction in the inner member 12), the outer peripheral surface of the rubber elastic body 16 is not covered by the outer member 14 and is exposed. Moreover, in the exposed portion in the central cylindrical portion 34 of the rubber elastic body 16, a buffer collision portion 38 protruding radially outward at a predetermined height is integrally formed in a substantially rectangular terrace shape bent along the circumferential direction of the inner member 12. In addition, a positioning hole 40 that reaches the rubber elastic body 16 is formed in the approximate center of one of the outer split bodies 28.

[0060] In addition, the brim-shaped rubber portion 36 provided at both axial ends of the rubber elastic body 16 is formed into a diameter-expanding shape slightly inclined toward the axial outer side. In addition, the outer peripheral surface of the brim-shaped rubber portion 36 is formed as an outer peripheral exposed surface 44 that is not covered by the inner member 12 and the outer member 14 and is exposed over the entire circumference. That is, at both axial ends of the rubber elastic body 16, outer peripheral exposed surfaces 44, 44 as end exposed surfaces that are exposed toward the radial outer side are formed respectively.

[0061] It should be noted that, in the present embodiment, the outer peripheral exposed surface 44 of the brim-shaped rubber portion 36 is formed in a groove shape that extends over the entire circumference in a substantially constant cross-sectional shape constituted by a curved concave shape (substantially circular arc shape) that opens on the outer peripheral surface. Thus, in the brim-shaped rubber portion 36 where the deformation of the surface is restricted by the inner brim-shaped portion 22 and the outer brim-shaped portion 32, the area of the free surface is ensured. In addition, the reduction of the tensile stress in the outer peripheral exposed surface 44 during the application of an external force, and the improvement of the durability performance and load resistance performance based thereon are also achieved.

[0062] As described above, the rubber bushing 10 for a shaft beam according to the present embodiment has a bushing main body 46 formed by elastically connecting an inner member 12 and an outer member 14 with a rubber elastic body 16. Such a bushing main body 46 can be configured, for example, as an integrally vulcanized molded article obtained by vulcanizing and bonding the inner member 12 and the outer member 14 during the vulcanization molding of the rubber elastic body 16.

[0063] Furthermore, covering rings 48, 48 prepared separately as independent members are assembled to the bushing main body 46.

[0064] As Figure 6 shown in (a) of Figure 6 and (b) of

[0065] the covering ring 48 is integrally formed in a circular ring shape. The shape of the outer peripheral side of the covering ring 48 is not particularly limited. For example, as shown in the figure, it is a simple cylindrical shape. The shape of the inner peripheral side of the covering ring 48 is formed in a substantially circular arc-shaped cross-sectional shape that bulges toward the inner peripheral side corresponding to the shape of the outer peripheral exposed surface 44 formed on the bushing main body 46.

[0066] It should be noted that, in the present embodiment, the outer peripheral exposed surface 44 of the bushing main body 46 is formed in a substantially constant cross-sectional shape over the entire circumference. Correspondingly, the cross-sectional shape of the covering ring 48 is also formed in a substantially constant shape over the entire circumference.

[0067] It should be noted that the elastic material used in the covering ring 48 can be any known flame-retardant elastic material considering the required degree and conditions of flame retardancy. Preferably, materials that meet European flame-retardant standards such as EN45545-2 are used. In addition, the covering ring 48 is an independent component relative to the bushing body 46, and its material does not directly affect the basic characteristics of the rubber elastomer 16, nor is it easy to imagine a large deformation caused by an input load like the rubber elastomer 16. Therefore, in addition to achieving the required flame retardancy of the material of the covering ring 48 by, for example, using chlorosulfonated polyethylene (CSM) or ethylene propylene diene rubber (EPDM) with a flame-retardant formulation, the required flame retardancy can also be achieved by, for example, providing a flame-retardant coating on the surface of the covering ring 48.

[0068] The elastic covering ring 48 is assembled to the outer peripheral exposed surface 44 of the bushing body 46 in a state where the covering ring 48 is expanded and deformed elastically, so that the inner peripheral portion of the covering ring 48 enters the groove-shaped inner part of the outer peripheral exposed surface 44, and it can be assembled in a state of preventing axial detachment.

[0069] Especially in the present embodiment, compared with the outer diameters of the inner capping portions 22 and the outer capping portions 32 that form the axial two side wall portions of the groove-shaped outer peripheral exposed surface 44, the radial center point 50 of the covering ring 48 is located on the inner peripheral side, and the covering ring 48 enters deeper into the groove-shaped portion of the outer peripheral exposed surface 44. In addition, in the present embodiment, in Figure 3 the cross-section of the shown groove-shaped outer peripheral exposed surface 44, the covering ring 48 is assembled in a state of entering more than half of the groove depth direction from the opening between the inner capping portion 22 and the outer capping portion 32 toward the radial inner side.

[0070] It should be noted that the inner peripheral surface of the covering ring 48 may also contact the groove-shaped outer peripheral exposed surface 44 of the rubber elastomer 16 throughout the entire surface, but in the present embodiment, as Figure 3 shown, a gap 54 is set between the bottom of the groove-shaped outer peripheral exposed surface 44 and the covering ring 48. In Figure 3 the cross-section, at the opening of the outer peripheral exposed surface 44 located between the inner capping portion 22 and the outer capping portion 32 in the axial direction, the axial both ends of the covering ring 48 abut against the inner capping portion 22 and the outer capping portion 32, and the gap 54 disappears. On the other hand, in Figure 5 the cross-section, on the axial inner side of the outer peripheral exposed surface 44, the gap 54 is open to the outer peripheral surface (the axial inner surface of the capping rubber portion 36) of the rubber elastomer 16 that is not fixedly connected to the outer member 14 (outer split bodies 28, 28) and forms a free surface.

[0071] By setting the bottom of the groove-shaped outer peripheral exposed surface 44 not to contact the covering ring 48, for example, it is possible to improve the degree of freedom of deformation of the free surface of the rubber elastic body 16, reduce wear and damage caused by sliding contact during deformation, reduce the deviation of the assembly state of the covering ring 48 caused by manufacturing errors, etc. In particular, in the present embodiment, the gap 54 between the bottom of the outer peripheral exposed surface 44 and the covering ring 48 is set to be continuous throughout the entire circumference in the circumferential direction. However, this gap 54 can also be set locally in the circumferential direction, or a gap 54 can be set between the covering ring 48 throughout the entire surface of the outer peripheral exposed surface 44.

[0072] In addition, the axial thickness dimension of the inner peripheral portion of the covering ring 48 becomes smaller in a manner of entering the groove-shaped outer peripheral exposed surface 44 from the outer peripheral side, but the axial thickness dimension of the outer peripheral portion of the covering ring 48 is larger than the groove-shaped opening portion of the outer peripheral exposed surface 44. Thus, when the covering ring 48 is assembled to the bushing body 46, the covering ring 48 entirely covers the groove-shaped opening portion of the outer peripheral exposed surface 44, and covers it in such a way that the outer peripheral exposed surface 44 can hardly be seen even when visually observed from the radially outer side.

[0073] In particular, in the present embodiment, in the cross-sectional shape of the covering ring 48, one surface in the axial direction is formed as an inclined tapered surface 52. Moreover, based on the elasticity of the covering ring 48 in the diameter-reducing direction in the assembled state, the tapered surface 52 abuts against the inner brim-shaped portion 22, and thus the other surface in the axial direction is pressed against the outer brim-shaped portion 32. Thus, in the assembled state of the covering ring 48, it is stably positioned on the outer peripheral exposed surface 44 of the bushing body 46 in the axial direction.

[0074] On this basis, in the present embodiment, an engaging portion 56 protruding outward in the axial direction is formed at the outer peripheral end of the covering ring 48. Moreover, in the assembled state of being assembled to the bushing body 46, the engaging portion 56 is engaged in such a way as to hook the outer peripheral surface of the inner brim-shaped portion 22 made of a rigid material throughout the entire circumference. Thus, it is possible to further improve the stability of the assembled state of the covering ring 48, and it is possible to easily confirm the presence or absence of the assembly of the covering ring 48 by visual observation from the outer side in the axial direction. It should be noted that, regarding the presence or absence of the assembly of the covering ring 48 and the assembly state, in order to make visual confirmation easier, the chroma and hue of the covering ring 48 can also be adjusted for easy observation.

[0075] The rubber bushing 10 for an axle beam having the structure as described above is used for an axle beam type axle box support device that couples a wheel axle and a bogie frame in a railway vehicle bogie.

[0076] Specifically, the axle beam type axle box support device 57 is as Figure 7As schematically illustrated in the medium model, the axle box 64 that rotatably supports the axle 62 of the wheel set 62 is movably and resiliently supported in the vertical direction of the vehicle by a coil spring 60. An axle beam 66 extending in the longitudinal direction of the vehicle is integrally provided. The rubber bushing 10 for the axle beam of the present embodiment is assembled to the mounting portion of the front end of the axle beam 66 that is mounted to the bogie frame 58, and the axle box 64 is resiliently supported on the bogie frame 58 in the longitudinal and lateral directions of the vehicle. It should be noted that a split-type cylindrical fitting portion is provided at the front end of the axle beam 66. By externally fitting and fastening the outer member 14 of the rubber bushing 10 for the axle beam to the cylindrical fitting portion, the central axis of the rubber bushing 10 for the axle beam is assembled in a state of extending in the lateral direction of the vehicle. On the other hand, the inner shaft end portions 24, 24 at both axial ends of the inner member 12 of the rubber bushing 10 for the axle beam are inserted through the support holes provided in the bogie frame 58 and are fixedly assembled.

[0077] In the assembled state as described above, the rubber bushing 10 for the axle beam is located below the bogie frame 58. Moreover, the inner peripheral surface of the rubber elastic body 16 of the bushing body 46 is covered by the inner member 12, and the outer peripheral surface is covered by the outer member 14 and the split-type cylindrical fitting portion at the front end of the axle beam 66 that is externally fitted and fixed to the outer member 14. However, the outer peripheral exposed surfaces 44, 44 of the rubber elastic body 16 in the bushing body 46 are not covered by the outer member 14 and the cylindrical fitting portion of the axle beam 66 and are exposed on the outer peripheral surface. These outer peripheral exposed surfaces 44, 44 are in a state of directly facing the road surface during the running of the railway vehicle.

[0078] Here, in the rubber bushing 10 for the axle beam of the present embodiment, the outer peripheral exposed surfaces 44, 44 are covered by the covering rings 48, 48 assembled to both axial side portions of the bushing body 46. Therefore, for example, even when flames from below, such as from the road surface and between the rails, and from the side reach the rubber bushing 10 for the axle beam due to an external fire, the rubber elastic body 16 can be prevented from being directly exposed to the flames.

[0079] In particular, the covering ring 48 is formed as a member independent of the rubber elastic body 16, which can improve the fire resistance of the rubber elastic body 16, etc. Therefore, while improving the fire resistance, etc. required for the rubber bushing 10 for the axle beam by the covering ring 48, a relatively large degree of design freedom related to the material, spring characteristics, etc. of the rubber elastic body 16 can be ensured.

[0080] Moreover, as described above, in the assembled state where the railway vehicle bogie (bogie frame) 58 is assembled to the axle box support device 57, the inner peripheral surface and the outer peripheral surface of the rubber elastic body 16 are fixedly covered by the inner member 12, the outer member 14, and the cylindrical fitting portion at the front end of the axle beam 66, and the outer peripheral exposed surfaces 44, 44 of the rubber elastic body 16 are non-fixedly covered by the covering rings 48, 48. Moreover, the entire rubber elastic body 16 is in a state where the end exposed surface cannot be directly visually observed from the outside in any direction. Therefore, the fire defense performance against flames from any direction is excellent, and it is also easy to meet conditions such as flame retardant standards.

[0081] In addition, in the axle beam rubber bushing 10 of the present embodiment, a covering ring 48 that is an elastic body with an overall annular covering portion and can be expanded in diameter is adopted, and the covering ring 48 is assembled in such a way that it is embedded in the groove-shaped outer peripheral exposed surface 44 in the expanded diameter state. Therefore, when positioning and assembling the covering ring 48 to the bushing body 46, no special fixing member or fixing mechanism is required, and the assembly operation and structure are simple.

[0082] Next, in Figures 8 to 10 As the second embodiment of the rubber bushing for the axle box support device configured according to the structure of the present invention, a rubber bushing 70 for a single link is shown, which is assembled to a single link that connects the wheel axle to the bogie frame and is assembled to the mounting portions on the wheel axle side and the bogie frame side of the single link.

[0083] The rubber bushing 70 for a single link in the present embodiment is integrally formed into a substantially cylindrical bushing structure, and includes an inner member 72 as an inner member and an outer member 74 as an outer member disposed to be separated on its outer periphery. Further, the inner member 72 and the outer member 74 are elastically connected by a rubber elastic body 76.

[0084] The inner member 72 has a rod shape that extends linearly, and integrally has a central rod portion 80 located at the central portion in the axial direction and a pair of inner shaft end portions 82, 82 that extend from both axial ends of the central rod portion 80 toward both sides in the axial direction.

[0085] Both the central rod portion 80 and the inner shaft end portions 82 of the inner member 72 are formed into a cross-sectional shape with the distance between opposite sides. That is, it is formed into a solid rod shape having an outer peripheral shape as follows: a rod with a circular outer peripheral surface is partially cut by a pair of parallel surfaces (double surfaces) opposed in the axial vertical direction and chamfered.

[0086] It should be noted that in the central rod portion 80 and the inner shaft end portions 82, 82 on both sides in the axial direction, the directions of the distances between opposite sides face the same axial vertical direction. In addition, a through hole 84 that penetrates in the axial vertical direction is formed at approximately the center of the chamfered plane in each inner shaft end portion 82.

[0087] In addition, with respect to the central rod portion 80, in each inner shaft end portion 82, both the opposite side distance dimension (the radially outer dimension opposite to the opposite side distance) and the diameter of the non-chamfered circular arc portion are reduced by a substantially constant dimension. As a result, at both axial ends of the central rod portion 80, a special-shaped annular step 86 is formed that is located between the inner shaft end portions 82 and extends throughout the entire circumference.

[0088] On the other hand, the outer member 74 is composed of a cylindrical metal sleeve. The outer member 74 is formed with a substantially constant thickness dimension as a whole, and with respect to the axial length of the outer member 74, it is shortened on both axial sides compared to the central rod portion 80 of the inner member 72.

[0089] Moreover, a rubber elastomer 76 is disposed between the opposed surfaces in the direction perpendicular to the axis of the central rod portion 80 of the inner member 72 and the outer member 74. The rubber elastomer 76 is fixedly connected to the outer peripheral surface of the central rod portion 80 in a close contact state on the inner peripheral surface, and is fixedly connected to the inner peripheral surface of the outer member 74 in a close contact state on the outer peripheral surface.

[0090] It should be noted that the rubber elastomer 76 is formed as a substantially thick-walled cylindrical shape as a whole, and the thickness dimension in the direction perpendicular to the axis varies in the circumferential direction. That is, on the surfaces of the arcuate outer peripheral surfaces 88, 88 of the inner member 72, it is formed with a substantially constant thickness dimension in the circumferential direction, but on the surfaces of the opposite side distance outer peripheral surfaces 90, 90 orthogonal thereto, the thickness dimension is larger and varies in the circumferential direction.

[0091] In addition, both axial end surfaces of the rubber elastomer 76 are formed as axial exposed surfaces 92, 92 that are end exposed surfaces. The above-mentioned axial exposed surfaces 92, 92 are formed as free surfaces that are not deformed and constrained by the inner member 72 and the outer member 74. In particular, in the present embodiment, the axial exposed surface 92 is formed in a groove shape that extends along the circumference with the bottom surface being a concave arcuate shape that bends toward the axial inside.

[0092] As described above, the single-link rubber bushing 70 of the present embodiment has a bushing main body 93 that is formed by elastically connecting the inner member 72 and the outer member 74 by using the rubber elastomer 16. Such a bushing main body 93 can be configured, for example, as an integrally vulcanized molded part that is vulcanized and bonded between the inner member 72 and the outer member 74 during the vulcanization molding of the rubber elastomer 76.

[0093] Furthermore, covering covers 94, 94, which are prepared separately as independent components, are assembled to the bushing main body 46.

[0094] As Figure 11As shown, the cover 94 is formed as a thin-walled ring extending circumferentially with a substantially L-shaped cross-section. Moreover, like the cover ring 48 in the first embodiment, the cover 94 is formed of an elastic material (high elastic body) such as a rubber elastomer or silicone having flame retardancy.

[0095] In the cover 94, the annular plate portion 96 extending radially has a planar shape substantially corresponding to the axial end face of the rubber elastomer 76. Further, in the cover 94, the cylindrical portion 98 extending axially projects from the outer peripheral edge portion of the annular plate portion 96 toward the axial inner side and is integrally formed. The axial length of the cylindrical portion 98 is substantially equal to the axial length from the axial end of the central rod portion 80 of the inner member 72 to the axial end of the outer member 74 (that is, 1 / 2 of the axial dimension difference between the central rod portion 80 and the outer member 74).

[0096] Furthermore, in the cover 94, an annular fixing frame 100 is fixedly connected to the inner peripheral end of the annular plate portion 96 formed in a shape substantially corresponding to the outer peripheral surface of the central rod portion 80 of the inner member 72. The fixing frame 100 is formed of a hard material such as metal, and the inner peripheral surface of the central hole 102 of the fixing frame 100 is formed in a shape substantially corresponding to the outer peripheral surface of the inner shaft end portion 82 of the inner member 72.

[0097] Moreover, the fixing frame 100 is externally fitted to the shaft end portion 82 of the inner member 72 and is fixedly connected to the inner member 72 by press-fitting, bonding, etc. in a positioning state where it abuts against the step 86, thereby fixedly assembling the cover 94 to the bushing main body 93.

[0098] It should be noted that the cover 94 may not contact the rubber elastomer 76 and the outer member 74, but may also abut during load input or contact in the initial single bushing state. In particular, since the cover 94 is formed of an elastic material and is formed as a thin wall in this embodiment and is easily deformable, the contact between the cover 94 and the rubber elastomer 76 and the outer member 74 hardly has an adverse effect on the dynamic characteristics of the single-link rubber bushing 70.

[0099] In particular, the cover 94 of this embodiment is formed in a substantially L-shaped cross-sectional shape and is assembled in a state where it is opposed to the axially exposed surface 92 of the rubber elastomer 76 formed in a groove-shaped cross-section opening axially outward with a sufficient gap 103 in the axial direction.

[0100] The single-link rubber bushing 70 of this embodiment having the structure as described above is used in a single-link type axle box support device for connecting a wheel axle to a bogie frame in a railway vehicle bogie.

[0101] Generally speaking, as Figure 12As schematically illustrated in the medium model, the single-link type axle box support device 104 includes an axle box 108. The axle box 108 is movably and cushioningly supported on the bogie frame 106 in the vertical direction of the vehicle by a coil spring, and supports the axle of the wheel set so as to be rotatable. The axle box 108 and the bogie frame 106 are connected by a single link 110 extending in the longitudinal direction of the vehicle. Moreover, single-link rubber bushings 70 are respectively assembled to the mounting portions of the axle box 108 and the bogie frame 106 at both axial ends of the single link 110, and both axial ends of the single link 110 are cushioningly connected to the axle box 108 and the bogie frame 106.

[0102] More specifically, an arm eye (assembly hole) penetrating in the left-right direction of the vehicle is formed at the axial end of the single link 110, and the outer member 74 of the single-link rubber bushing 70 is press-fitted and fixed to the arm eye for installation. On the other hand, the inner member 72 of the single-link rubber bushing 70 is fixedly installed on the axle box 108 and the bogie frame 106 by fixing members 112 such as bolts inserted through through holes 84, 84 formed at the inner shaft ends 82, 82.

[0103] In the above-described assembled state, the single-link rubber bushing 70 is located below the bogie frame 106, and the axially exposed surfaces 92, 92 of the rubber elastic body 76 that are not covered by the inner member 72 and the outer member 74 are formed in a state of being exposed to the outside in the left-right direction of the vehicle without being covered.

[0104] Here, in the single-link rubber bushing 70 of the present embodiment, the axially exposed surfaces 92, 92 are covered by covering covers 94, 94 assembled to both axial side portions of the bushing body 93. Therefore, similarly to the axle beam rubber bushing of the first embodiment, even when a flame caused by an external fire or the like reaches the single-link rubber bushing 70, the rubber elastic body 76 can be prevented from being directly exposed to the flame. In addition, the same technical effects as those of the first embodiment can be effectively achieved.

[0105] As described above, the embodiments of the present invention have been specifically exemplified and described, but the present invention is not limitedly interpreted by the above specific descriptions. For example, a metal having a higher heat resistance than the elastomer can be used to form a part of the covering portion, especially a part that has a risk of being exposed to high temperatures. Specifically, in the single-link rubber bushing 70 of the second embodiment, one of the annular plate portion 96 and the cylindrical portion 98 can also be formed of metal, or the annular plate portion 96 and the cylindrical portion 98 can be locally formed of metal.

[0106] In addition, in the axle beam rubber bushing 10 of the first embodiment, the inner peripheral portion of the covering ring 48 entering the groove-shaped outer peripheral exposed surface 44 may also be locally formed in the circumferential direction to obtain the positioning effect of the covering ring 48 relative to the bushing body 46.

[0107] In addition, the covering portion used in the present invention only needs to achieve the heat resistance, flame resistance, etc. required for a rubber bushing used as an axle box support device in a railway vehicle bogie, and the shape, material, etc. can be appropriately changed according to the required degree.

[0108] For example, in the bushing bodies 46 and 93, the covering portion does not necessarily need to cover the end exposed surface that is exposed to the outside in the assembled state of being assembled to a railway vehicle bogie over the entire surface. It is also possible to consider the direction of the assumed flame, etc., and determine and set the surface covered by the covering portion in the end exposed surface. In addition, if it is a situation where there is no interference or contact with other members under the assumed vibration input conditions, or the interference or contact with other members does not become a problem, etc., then the entire covering portion can also be formed of a hard material. In addition, in the above second embodiment, the covering portion is supported by the inner member, but it can also be supported by the outer member, or supported by an axle beam, a single link, etc. As long as it can be maintained in the assembled state, it does not need to be supported by other members either.

[0109] In addition, in the above embodiment, an example of applying the present invention to a rubber bushing for a railway bogie used in a single link type axle box support device and an axle beam type axle box support device is shown, but the application object of the present invention is not limited thereto. For example, the present invention can also be applied to a rubber bushing used in a traction device of a non-crossbeam bogie, a rubber bushing for connecting a crossbeam fixer assembled to a crossbeam bogie to the crossbeam and the bogie frame, or a rubber bushing used in various types of axle box support devices, etc.

[0110] In addition to this, although not listed one by one, the present invention can be implemented in various ways with various changes, corrections, improvements, etc. based on the knowledge of those skilled in the art. In addition, it goes without saying that as long as it does not deviate from the gist of the present invention, such embodiments are all included in the scope of the present invention.

[0111] Explanation of reference numerals

[0112] 10: Rubber bushing for axle beam;

[0113] 12: Inner member (inner side member);

[0114] 14: Outer member (outer side member);

[0115] 16: Rubber elastic body;

[0116] 18: Central hole;

[0117] 20: Central rod portion;

[0118] 22: Inner eaves-like portion;

[0119] 24: Inner shaft end;

[0120] 26: Through hole;

[0121] 28: Outer split body;

[0122] 30: Central plate-like part;

[0123] 32: Outer brim-like part;

[0124] 34: Central cylindrical part;

[0125] 36: Brim-like rubber part;

[0126] 38: Buffer part;

[0127] 40: Hole;

[0128] 44: Outer peripheral exposed surface (end exposed surface);

[0129] 46: Bushing body;

[0130] 48: Cover ring (covering part);

[0131] 50: Radial center point;

[0132] 52: Tapered surface;

[0133] 54: Gap;

[0134] 56: Engaging part;

[0135] 57: Axle beam type axle box support device;

[0136] 58: Bogie frame;

[0137] 60: Helical spring;

[0138] 62: Wheel axle;

[0139] 64: Axle box;

[0140] 66: Axle beam;

[0141] 70: Rubber bushing for single link;

[0142] 72: Inner member (inner side member);

[0143] 74: Outer member (outer side member);

[0144] 76: Rubber elastic body;

[0145] 80: Central rod part;

[0146] 82: Inner shaft end;

[0147] 84: Through hole;

[0148] 86: Step;

[0149] 88: Arc-shaped outer peripheral surface;

[0150] 90: Opposite side distance from the outer peripheral surface;

[0151] 92: Axial exposed surface (end exposed surface);

[0152] 93: Bushing body;

[0153] 94: Cover (covering part);

[0154] 96: Ring-shaped plate part;

[0155] 98: Cylindrical part;

[0156] 100: Fixed frame;

[0157] 102: Central hole;

[0158] 103: Gap;

[0159] 104: Single-link type axle box support device;

[0160] 106: Bogie frame;

[0161] 108: Axle box;

[0162] 110: Single link;

[0163] 112: Fixing piece.

Claims

1. A rubber bushing (10, 70) for a railway bogie, which is formed by connecting a shaft-shaped inner member (12, 72) and an outer member (14, 74) separated and arranged on the outer peripheral side of the inner member (12, 72) by a rubber elastomer (16, 76), and is a rubber bushing used in the bogie of a railway vehicle, wherein, At the axial ends of the rubber elastomers (16, 76), covering portions (48, 94) are provided by members independent of the rubber elastomers (16, 76). The covering portions (48, 94) cover, from the outside, the end exposed surfaces (44, 92) of the rubber elastomers (16, 76) that are exposed to the outside between the axial ends of the inner member (12, 72) and the outer member (14, 74). The covering portions (48, 94) are annular elastic bodies and are covering rings capable of expanding in diameter and deforming. The covering portions (48, 94) are assembled in such a way that they are embedded in the groove-shaped end exposed surfaces (44, 92) in the state after diameter expansion. The central portion in the axial direction of the inner member (12) is formed as a central rod portion (20) extending in a constant cylindrical shape. At the axial ends of the central rod portion (20), a pair of inner brim-shaped portions (22, 22) protruding in a flange shape toward the outer periphery are integrally formed. The outer member (14) is composed of a pair of outer split bodies (28, 28). Each outer split body (28) has a central plate-shaped portion (30) in an arc-shaped bent plate shape extending in the circumferential direction with a length less than half a circumference. At the axial ends of the central plate-shaped portion (30), outer brim-shaped portions (32) that expand in diameter toward the axial outside in a manner of being bent outward toward the outer periphery are integrally formed. The covering portion (48) is held sandwiched between the inner brim-shaped portion (22) and the outer brim-shaped portion (32). In the cross-sectional shape of the covering portion (48), one axial side surface is formed as an inclined conical surface (52). Based on the elasticity of the covering portion (48) in the diameter reduction direction in the assembled state, the conical surface (52) abuts against the inner brim-shaped portion (22), and thus the other axial side surface is pressed against the outer brim-shaped portion (32).

2. The rubber bushing (10) for a railway bogie according to claim 1, wherein, At the axial end of the rubber elastomer (16), a brim-shaped rubber portion (36) having a large diameter is formed. The brim-shaped rubber portion (36) is axially sandwiched between the axial ends of the inner member (12) and the outer member (14), and the outer peripheral surface of the brim-shaped rubber portion (36) is formed as the end exposed surface (44) and is covered by the covering portion (48).

3. The rubber bushing (70) for a railway bogie according to claim 1, wherein, The axial end of the rubber elastomer (76) has an axially exposed surface (92) that is exposed axially outward between the axial ends of the inner member (72) and the outer member (74). The axially exposed surface (92) is formed as the end exposed surface and is covered by the covering portion (94).

4. The rubber bushing (10, 70) for a railway bogie according to any one of claims 1 to 3, wherein, A gap (54, 103) is provided between the end exposed surfaces (44, 92) of the rubber elastomers (16, 76) and the covering portions (48, 94).

5. The rubber bushing (10, 70) for a railway bogie according to any one of claims 1 to 3, wherein, At least a part of the covering portions (48, 94) is in contact with the end exposed surfaces (44, 92) of the rubber elastomers (16, 76).

6. The rubber bushing (10, 70) for a railway bogie according to any one of claims 1 to 3, wherein, At least a part of the covering portions (48, 94) is formed of a highly elastic body.

7. The rubber bushing (10, 70) for a railway bogie according to claim 6, wherein, The covering parts (48, 94) are positioned to cover the exposed end surfaces (44, 92) of the rubber elastomers (16, 76) from the outside by utilizing the elasticity of the highly elastic body.

8. The rubber bushing (10, 70) for a railway bogie according to any one of claims 1 to 3, wherein, In a state where the rubber bushings (10, 70) for railway bogies are assembled to the bogies of the railway vehicle, the exposed end surfaces (44, 92) of the rubber elastomers (16, 76) are covered by the covering parts (48, 94) in a state where they cannot be directly visually observed from the outside from any direction.

9. The rubber bushing (10) for a railway bogie according to claim 1, wherein, The covering part (48) is assembled in a state where it enters more than half the depth direction of the groove from the opening between the axial directions of the inner brim-like part (22) and the outer brim-like part (32) toward the radially inner side.

Images