Cylindrical elastic coupling device for axle beam

Abstract

The present invention provides a cylindrical elastic coupling device for an axle beam, said cylindrical elastic coupling device having a novel structure and achieving stabilization of fixation to an inner shaft member of a stopper member.　Provided is a cylindrical elastic coupling device 10 for an axle beam, in which an inner shaft member 12 is elastically coupled to outer split bodies 14a, 14b with a main rubber elastic body 16, the inner shaft member 12 is attached to a truck frame 60, and the outer split bodies 14a, 14b are attached to a cylindrical housing part 72 that is provided to one end of an axle beam 70, wherein: a stopper member 28 is attached to the inner shaft member 12 to restrict the relative amount of displacement between the inner shaft member 12 and the outer split bodies 14a, 14b by abutment against the housing part 72; the stopper member 28 includes a hard base part 30 which is fixed to the inner shaft member 12, and an elastic part 32 which is fixed to the base part 30 to constitute the tip surface of the stopper member 28 with an elastic material; and the inner shaft member 12 and the base part 30 are fixed to each other with a press-fit pin 38.

Description

Cylindrical Elastic Coupling Device for Axle Bolsters

[0001] The present invention relates to a cylindrical elastic coupling device for an axle bolster that elastically couples one end of an axle bolster to a bogie frame of a railway vehicle.

[0002] Conventionally, in railway vehicles, a structure has been generally adopted in which an axle bolster extends from an axle box portion that supports an axle in the longitudinal direction of the vehicle, and an end portion of the axle bolster is elastically coupled to a bogie frame by a cylindrical elastic coupling device. As disclosed in Japanese Patent No. 7189809 (Patent Document 1), this cylindrical elastic coupling device for an axle bolster has a structure in which a pair of outer split members (outer portions) extending in the circumferential direction are disposed on the outer peripheral side of an inner shaft member (central shaft), and the inner shaft member and the pair of outer split members are elastically coupled to each other by a main body rubber elastic body (elastic portion). Then, both axial ends of the inner shaft member are attached to the bogie frame, and the outer split member is attached to a cylindrical housing portion provided at one end of the axle bolster, so that the axle bolster is elastically supported by the bogie frame via the cylindrical elastic coupling device for the axle bolster.

[0003] Japanese Patent No. 7189809

[0004] By the way, in the cylindrical elastic coupling device for an axle bolster, a stopper member may be provided to limit the relative displacement amount between the inner shaft member and the pair of outer split members in a specific radial direction where a large load input is expected. That is, in the cylindrical elastic coupling device for an axle bolster of Patent Document 1, since a large load during deceleration by a tread brake is input in the radial direction corresponding to the longitudinal direction of the vehicle, a stopper member (elastic stopper) protruding from the inner shaft member toward the outer periphery in the radial direction is provided. Then, when the inner shaft member and the housing portion abut against each other via the stopper member, the relative displacement amount between the inner shaft member and the outer split member is limited in a specific radial direction, and the durability of the main body rubber elastic body and the braking performance of the intended railway vehicle are realized.

[0005] Furthermore, the stopper member described in Patent Document 1 comprises a rigid base portion that constitutes the fixing portion to the inner shaft member, and an elastic portion (elastic material) fixed to the tip side of the base portion that constitutes the stopper contact surface. The stopper member is fixed to the inner shaft member by a mounting bolt inserted from the tip side into an open tip hole (large diameter hole portion) that opens on the tip surface.

[0006] However, in the structure of Patent Document 1, burrs may form on the inner surface of the open hole at the base of the stopper member. For example, if burrs form on the seating surface of the mounting bolt, the elasticity of the burrs trapped between the head of the mounting bolt and the seating surface will decrease over time, potentially causing the mounting bolt to loosen and reducing the fixing force of the stopper member. To prevent a decrease in bolt fastening force due to burr trapping, it is conceivable to remove the burrs after forming the elastic part. However, this removal process is time-consuming, and the seating surface of the mounting bolt at the base may be scraped during removal, potentially leading to problems such as reduced dimensional accuracy and increased susceptibility to rust.

[0007] Furthermore, when bolting the stopper member in place, the fixing force of the stopper member is stabilized by managing the tightening torque so that the mounting bolts are tightened to the appropriate torque. However, with this type of tightening torque management, it is difficult to accurately stabilize the fixing force of the stopper member. Specifically, for example, differences in the condition of the inner surface of the screw hole of the inner shaft member into which the mounting bolt is screwed, and differences in the dimensional tolerances of the screw hole and threads, may cause differences in the bolt fixing force of the stopper member even when the mounting bolt is tightened to the same torque.

[0008] Furthermore, in a structure where the stopper member is bolted in place, it is relatively easy to loosen or tighten the mounting bolts after the stopper member has been secured to the inner shaft member by tightening the mounting bolts with the appropriate torque. In such cases, there is a risk that the fixing force of the stopper member by the mounting bolts may not be exerted as intended.

[0009] The present invention was made against the background described above, and its objective is to provide a novel cylindrical elastic coupling device for shaft beams that stabilizes the fixing of the stopper member to the inner shaft member.

[0010] The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is illustrative and can be combined with others as appropriate. Furthermore, the multiple components described in each embodiment can be recognized and adopted as independently as possible, and can be combined with any component described in another embodiment as appropriate. Thus, the present invention is not limited to the embodiments described below, and various other embodiments can be realized.

[0011] In the first embodiment, a pair of outer segments are arranged on the outer circumference of an inner shaft member, facing each other in a direction perpendicular to the axis, and the inner shaft member and the pair of outer segments are elastically connected to each other by a main rubber elastic body, the inner shaft member is attached to the bogie frame of a railway vehicle, and the pair of outer segments are attached to a cylindrical housing portion provided at one end of the axle beam, thereby elastically connecting the bogie frame and the axle beam, in a cylindrical elastic coupling device for an axle beam, wherein the inner shaft member is the same as the railway vehicle A stopper member is attached in either the front-rear direction to limit the relative displacement between the inner shaft member and the pair of outer divisions by contact with the housing portion. The stopper member has a rigid base fixed to the inner shaft member, and an elastic portion fixed to the base, with the end surface of the stopper member opposite to the inner shaft member being made of an elastic material. The inner shaft member and the base of the stopper member are fixed to each other by a press-fit pin.

[0012] In the cylindrical elastic coupling device for shafts and beams constructed according to this embodiment, the stopper member is fixed to the inner shaft member by press-fitting a pin rather than by bolt fixing. Therefore, even if an elastic burr is formed on the seating surface of a separate press-fitting pin, for example, changes in fixing force due to burr degradation are suppressed. That is, with bolt fixing, if the contact force between the bolt head and the seating surface decreases, the pressing force between the threads decreases, which directly leads to bolt loosening and a decrease in fixing force. However, with pin press-fitting, the fixing force is exerted based on the force acting radially between the shaft portion of the press-fitting pin and the inner circumferential surface of the press-fitting hole. Therefore, even if the contact force between the head of the press-fitting pin and the seating surface decreases due to burr degradation, a decrease in fixing force is less likely to be a problem. For this reason, the fixing of the stopper member is more stable compared to the conventional structure in which the stopper member is bolted from the tip side with a separate bolt. In addition, the work of removing burrs can be omitted, and problems such as damage to the seating surface associated with burr removal are avoided.

[0013] Furthermore, in conventional structures where the stopper member is bolted to the inner shaft member, it is difficult to directly control the axial force (pull-out force), which is the resistance force against the separation of the stopper member from the inner shaft member. Since the axial force is indirectly controlled by controlling the tightening torque of the mounting bolts, it is possible that the axial force may differ even with the same tightening torque. However, in this embodiment, since the stopper member is pin-press-fitted to the inner shaft member, it is possible to control the axial force more directly based on the resistance force when the pin is press-fitted, and the fixing force of the stopper member to the inner shaft member can be stabilized with greater precision.

[0014] Since the process of pulling out or pushing in a press-fit pin is more difficult than the process of loosening or tightening a bolt, the fixing force of the stopper member is less likely to change from its intended state.

[0015] The second embodiment is a cylindrical elastic coupling device for an axial beam as described in the first embodiment, wherein the tip surface of the stopper member that contacts the housing portion is a smoothly continuous stopper contact surface.

[0016] According to the cylindrical elastic coupling device for axial beams with a structure conforming to this embodiment, the tip surface of the stopper member is a smooth stopper contact surface without holes for inserting a press-fit pin, so that the pressure-receiving area of ​​the stopper member can be efficiently secured, thereby improving the durability of the stopper member while ensuring stopper performance.

[0017] The third embodiment is a cylindrical elastic coupling device for an axial beam as described in the first embodiment, wherein the stopper member has an open tip hole formed on the tip surface that abuts against the housing portion.

[0018] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the stopping action caused by the contact between the stopper member and the housing can be adjusted by the opening at the tip surface of the stopper member. Therefore, the impact noise and shock sensation that occur when the stopper member and the housing come into contact can be reduced.

[0019] The fourth aspect is a cylindrical elastic coupling device for a shaft beam as described in the third aspect, wherein the press-fit pin, which is separate from the inner shaft member and the stopper member, is press-fitted into the inner shaft member from the tip side of the stopper member through the tip opening hole, thereby fixing the inner shaft member and the stopper member to each other.

[0020] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the stopper member and the inner shaft member can be pin-press-fitted and fixed from the tip side of the stopper member by a separate press-fit pin inserted from the tip side into an open tip hole opening on the tip surface of the stopper member. The tip surface of the stopper member that abuts the housing is exposed toward the outer circumference in the standalone state of the cylindrical elastic coupling device for shafts and beams before it is mounted on the housing, making it easy to press-fit the stopper member from the tip side.

[0021] The fifth embodiment is a cylindrical elastic coupling device for an axial beam described in any one of the first to third embodiments, wherein the press-fit pin is integrally formed with the stopper member.

[0022] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the number of parts can be reduced because the press-fit pin is integrally formed with the stopper member. Furthermore, since the press-fit pin is fixed to the stopper member, the press-fitting work is made easier compared to, for example, when a separate press-fit pin is inserted through the stopper member and then press-fitted into the inner shaft member.

[0023] The sixth embodiment is a cylindrical elastic coupling device for an axial beam described in any one of the first to fourth embodiments, wherein the press-fit pin is separate from the inner axial member and the stopper member, and is press-fitted into the inner axial member and the stopper member, respectively.

[0024] According to the cylindrical elastic coupling device for shafts and beams with a structure conforming to this embodiment, compared to the case in which a press-fit pin is integrally formed with the stopper member or inner shaft member, machining such as cutting is simplified, thereby facilitating the manufacture of the stopper member or inner shaft member.

[0025] The seventh embodiment is a cylindrical elastic coupling device for an axial beam described in any one of the first to sixth embodiments, wherein a rotation limiting mechanism is provided to limit the relative amount of rotation of the stopper member with respect to the inner shaft member around the press-fit pin.

[0026] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, it becomes easier to attach the stopper member to the inner shaft member in the appropriate orientation around the press-fit pin.

[0027] The eighth aspect is a cylindrical elastic coupling device for a shaft beam described in the seventh aspect, wherein the overlapping surfaces of the inner shaft member and the stopper member are rotation-restricting surfaces that curve in the circumferential direction of the inner shaft member, and the rotation-restricting mechanism is formed by the overlapping of these rotation-restricting surfaces.

[0028] According to the cylindrical elastic coupling device for shafts and beams with a structure conforming to this embodiment, the overlapping surface between the inner shaft member and the stopper member serves as a rotation limiting surface, allowing a rotation limiting mechanism to be provided with a simple structure.

[0029] The ninth aspect is a cylindrical elastic coupling device for an axial beam as described in the seventh or eighth aspect, wherein the rotation limiting mechanism includes a rotation limiting portion that limits the relative amount of rotation of the stopper member around the press-fit pin with respect to the inner shaft member by engaging with the stopper member.

[0030] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the relative amount of rotation of the stopper member around the press-fit pin with respect to the inner shaft member can be more reliably limited by the locking of the stopper member and the rotation limiting part.

[0031] The tenth aspect is a cylindrical elastic coupling device for an axial beam described in any one of the seventh to ninth aspects, wherein the rotation limiting mechanism exerts a rotation limiting effect that limits the amount of relative rotation of the stopper member with respect to the inner shaft member during the initial stage of press-fitting the press-fit pin.

[0032] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the amount of relative rotation of the stopper member with respect to the inner shaft member is limited by the rotation limiting mechanism during the initial stage of press-fitting the press-fit pin. Therefore, the stopper member and the inner shaft member can be appropriately positioned around the press-fit pin during the initial stage of press-fitting, when the fixing force between the stopper member and the inner shaft member due to the pin press-fitting is relatively small.

[0033] The eleventh embodiment is a cylindrical elastic coupling device for a shaft beam described in any one of the first to tenth embodiments, wherein an intermediate member is provided, one of which is an inner-side corresponding surface superimposed on the outer circumferential surface of the inner shaft member, and the other side is a stopper-side corresponding surface superimposed on the inner shaft member side surface of the stopper member, the intermediate member has a pin insertion hole formed therethrough that opens to the inner-side corresponding surface and the stopper-side corresponding surface, the intermediate member is disposed between the inner shaft member and the stopper member, and the stopper member is fixed to the inner shaft member by the press-fit pin inserted through the pin insertion hole of the intermediate member without press-fitting.

[0034] According to the cylindrical elastic coupling device for shafts and beams with a structure conforming to this embodiment, for example, when attaching stopper members to multiple types of inner shaft members with different outer surface shapes, the stopper members can be standardized by preparing multiple types of intermediate members corresponding to the outer surface shapes of the inner shaft members. Compared to stopper members that require appropriate stopper characteristics, intermediate members can have a simpler structure and are easy to change in shape and dimensions. Therefore, design changes are easier and costs are reduced compared to preparing multiple types of stopper members to match the inner shaft members.

[0035] The twelfth aspect is a cylindrical elastic coupling device for a shaft beam as described in the eleventh aspect, wherein a first rotation limiting portion is provided to limit the amount of relative rotation of the stopper member with respect to the intermediate member around the press-fit pin, and a second rotation limiting portion is provided to limit the amount of relative rotation of the intermediate member with respect to the inner shaft member around the press-fit pin, and a rotation limiting mechanism that limits the amount of relative rotation of the stopper portion with respect to the inner shaft member around the press-fit pin is configured by the cooperation of the first rotation limiting portion and the second rotation limiting portion.

[0036] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the amount of relative rotation between the stopper member and the inner shaft member can be limited via the intermediate member by providing a first rotation limiting part that relatively positions the stopper member and the intermediate member, and a second rotation limiting part that relatively positions the intermediate member and the inner shaft member, with respect to rotation around the press-fit pin.

[0037] The thirteenth aspect is a cylindrical elastic coupling device for an axial beam as described in the twelfth aspect, wherein the first rotation limiting portion includes a restricting wall portion that protrudes toward the stopper member and limits the relative amount of rotation of the stopper member with respect to the intermediate member around the press-fit pin by engaging with the stopper member, and the second rotation limiting portion is configured such that the inner side corresponding surface of the intermediate member, which is curved in the circumferential direction of the inner shaft member, is superimposed on the inner shaft member.

[0038] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the relative amount of rotation between the stopper member and the intermediate member can be effectively limited by the locking of the stopper member and the regulating wall. Furthermore, a second rotation limiting portion can be provided with a simple structure by utilizing the cylindrical curved surface on the outer circumferential surface of the inner shaft member.

[0039] The fourteenth aspect is a cylindrical elastic coupling device for an axial beam described in the twelfth or thirteenth aspect, wherein the rotation limiting mechanism exerts a rotation limiting effect that limits the amount of relative rotation of the stopper member with respect to the inner shaft member during the initial stage of press-fitting the press-fit pin.

[0040] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the amount of relative rotation of the stopper member with respect to the inner shaft member is limited by the rotation limiting mechanism during the initial stage of press-fitting the press-fit pin. Therefore, the stopper member and the inner shaft member can be appropriately positioned around the press-fit pin during the initial stage of press-fitting, when the fixing force between the stopper member and the inner shaft member due to the pin press-fitting is relatively small.

[0041] The fifteenth embodiment is a cylindrical elastic coupling device for an axial beam described in any one of the first to fourteenth embodiments, wherein the elastic part is made of a material harder than the main rubber elastic body.

[0042] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, the elastic part is made of a harder material than the main rubber elastic body, thereby ensuring durability in the elastic part of the stopper member that is subjected to a large stopper load. Furthermore, because the elastic part is made of a harder material than the main rubber elastic body, the relative displacement between the inner shaft member and a pair of outer segmented bodies can be effectively limited.

[0043] The sixteenth embodiment is a cylindrical elastic coupling device for an axial beam described in any one of the first to fifteenth embodiments, wherein the elastic portion of the stopper member is a laminated structure comprising a tip elastic body constituting the tip surface of the stopper member, an intermediate elastic body fixed to the tip side of the base, and a rigid intermediate restraining member disposed between the tip elastic body and the intermediate elastic body.

[0044] According to the cylindrical elastic coupling device for a shaft key configured with the structure according to this aspect, when the front end surface of the stopper member is pressed against the housing portion and a stopper load is input to the stopper member, compared with the stopper member having a single-layer elastic portion, while adjusting the spring characteristics of the entire stopper member, the total thickness of the tip elastic body and the intermediate elastic body can be increased, and the durability of the elastic portion can be improved.

[0045] The seventeenth aspect is the cylindrical elastic coupling device for a shaft key described in the sixteenth aspect, in which the tip elastic body and the intermediate elastic body are formed of the same elastic material.

[0046] According to the cylindrical elastic coupling device for a shaft key configured with the structure according to this aspect, it becomes easier to simultaneously mold the tip elastic body and the intermediate elastic body.

[0047] The eighteenth aspect is the cylindrical elastic coupling device for a shaft key described in any one of the first to seventeenth aspects, in which the press-fit pin protrudes from the stopper member toward the inner shaft member, and the maximum protruding length dimension of the press-fit pin from the stopper member is larger than the difference between the diameter dimension of the outer peripheral surface of the pair of outer split members in the mounted state to the housing portion and the diameter dimension of the front end surface of the stopper member.

[0048] According to the cylindrical elastic coupling device for a shaft key configured with the structure according to this aspect, in the mounted state to a railway vehicle, before the press-fit pin protruding from the stopper member comes out of the inner shaft member, the front end surface of the stopper member contacts the housing portion, and the dropping of the press-fit pin from the inner shaft member is prevented, so that the separation of the stopper member from the inner shaft member can be prevented.

[0049] The nineteenth aspect is the cylindrical elastic coupling device for a shaft key described in any one of the first to eighteenth aspects, in which a window portion penetrating in the radial direction is formed in at least one of the pair of outer split members, and the stopper member is exposed through the window portion.

[0050] According to the cylindrical elastic coupling device for shafts and beams constructed in accordance with this embodiment, when mounted on a railway vehicle, the stopper member contacts the housing through the window, thereby exhibiting a stopper action that limits the relative displacement between the inner shaft member and the pair of outer split parts. Furthermore, the installation of the stopper member to the inner shaft member can be performed through the window, which facilitates the pin press-fitting and fixing work.

[0051] According to the present invention, in a cylindrical elastic coupling device for shaft beams, the fixing of the stopper member to the inner shaft member is stabilized.

[0052] A plan view showing a rubber bushing for shaft beams as the first embodiment of the present invention. A left side view of the rubber bushing for shaft beams shown in Figure 1. A cross-sectional view of the rubber bushing for shaft beams shown in Figure 1, corresponding to the III-III section in Figure 2. A cross-sectional view of the rubber bushing for shaft beams shown in Figure 1, corresponding to the IV-IV section in Figure 3. A plan view of the inner shaft member constituting the rubber bushing for shaft beams shown in Figure 1. A front view of the stopper member constituting the rubber bushing for shaft beams shown in Figure 1. A cross-sectional view of the VII-VII section in Figure 6. A cross-sectional view of the VIII-VIII section in Figure 6. A diagram showing the state in which the rubber bushing for shaft beams shown in Figure 1 is mounted on a railway vehicle. A cross-sectional view showing a rubber bushing for shaft beams as the second embodiment of the present invention. A cross-sectional view of the rubber bushing for shaft beams shown in Figure 10, corresponding to the X-X section in Figure 11. A perspective view of the intermediate member constituting the rubber bushing for shaft beams shown in Figure 10, corresponding to the XI-XI section in Figure 10. A perspective view showing the intermediate member shown in Figure 12 from a different angle. A different intermediate member from Figure 12. A cross-sectional view of the main part showing the provided shaft beam rubber bush. A perspective view of the intermediate member constituting the shaft beam rubber bush shown in Figure 14. A perspective view of the intermediate member of Figure 14 from a different angle. A cross-sectional view of the shaft beam rubber bush as a third embodiment of the present invention, corresponding to the XVII-XVII section of Figure 18. A cross-sectional view of the shaft beam rubber bush shown in Figure 17, corresponding to the XVIII-XVIII section of Figure 17. A cross-sectional view of the shaft beam rubber bush as a fourth embodiment of the present invention, corresponding to the XIX-XIX section of Figure 20. A cross-sectional view of the shaft beam rubber bush shown in Figure 19, corresponding to the XX-XX section of Figure 19. A cross-sectional view of the shaft beam rubber bush as a fifth embodiment of the present invention, corresponding to the XXI-XXXI section of Figure 22. A cross-sectional view of the shaft beam rubber bush shown in Figure 21, corresponding to the XXII-XXII section of Figure 21. A perspective view of the inner shaft member constituting the shaft beam rubber bush shown in Figure 21.

[0053] Embodiments of the present invention will be described below with reference to the drawings.

[0054] Figures 1 to 4 show a rubber bushing 10 for a shaft beam as a cylindrical elastic coupling device for a shaft beam, as a first embodiment of the present invention. The rubber bushing 10 for a shaft beam has a structure in which an inner shaft member 12 and front and rear outer splits 14a and 14b, which are arranged opposite each other on the outer circumference of the inner shaft member 12, are elastically connected to each other by a main rubber elastic body 16. In the following description, as a general rule, the vertical direction refers to the vertical direction in Figure 2, the front and rear direction refers to the left and right direction in Figure 2, and the left and right direction refers to the left and right direction in Figure 1.

[0055] The inner shaft member 12 is rod-shaped and extends linearly in the left-right direction as a whole, and is a highly rigid member made of a metal such as iron or an aluminum alloy. As shown in Figure 5, the inner shaft member 12 has a structure in which a cylindrical central shaft body 18, a pair of flange-shaped inner flange portions 20, 20 that protrude outward at both axial ends of the central shaft body 18, and a pair of mounting portions 22, 22 that protrude further axially outward than the inner flange portions 20, 20 are integrally formed.

[0056] The central shaft body 18 has a substantially constant circular cross-section and extends linearly in the left-right direction. The central shaft body 18 has press-fit holes 24 that open to the outer surface. The press-fit holes 24 are bottomed concave shapes with a substantially circular cross-section and are provided in a part of the circumferential direction so as to open forward in the axial central portion of the central shaft body 18.

[0057] The inner flange portions 20, 20 are annular plate-shaped, with the axial outer surface widening in a direction approximately perpendicular to the axis, and the inner circumference portion of the axial inner surface being tapered, with the inner circumference portion gradually becoming thinner towards the outer circumference, and the outer circumference portion widening to a substantially constant thickness.

[0058] As shown in Figures 1 and 2, the mounting portion 22 has a roughly polygonal prism shape and has bolt holes 26 that pass through it linearly in the vertical direction. The mounting portion 22 is then fixed to the trolley frame 60, which will be described later, by fastening bolts (not shown) that are inserted through the bolt holes 26.

[0059] Furthermore, the shape of the inner shaft member 12 is not limited by the specific description of the embodiment, and the specific shapes of each part constituting the inner shaft member 12 (the central shaft body 18, inner flange portion 20, mounting portion 22, and bolt hole 26 in this embodiment) are not particularly limited.

[0060] As shown in Figure 3, a stopper member 28 is attached to the central shaft body 18 of the inner shaft member 12. The stopper member 28 is substantially rectangular in shape when viewed from the front as shown in Figure 6. As shown in Figures 6 to 8, the stopper member 28 comprises a rigid base portion 30 fixed to the inner shaft member 12 and an elastic portion 32 provided on the tip side opposite to the inner shaft member 12 relative to the base portion 30.

[0061] The base portion 30 is a highly rigid member made of a metal such as iron or an aluminum alloy, and includes a roughly rectangular plate-shaped base body 34. As shown in Figure 7, the tip surface of the base body 34 that overlaps with the elastic portion 32 is a curved surface that curves in the circumferential direction of the inner shaft member 12. Furthermore, the base end surface of the base body 34 that overlaps with the central shaft body 18 of the inner shaft member 12 is an inner-side corresponding surface 36, which is a curved surface corresponding to the outer circumferential surface of the inner shaft member 12.

[0062] As shown in Figures 6 to 8, a solid press-fit pin 38 is integrally formed on the base 30 of the stopper member 28, protruding from the base body 34 toward the inner shaft member 12. The press-fit pin 38 is cylindrical with a substantially constant circular cross-section and extends linearly. In this embodiment, the maximum protruding length dimension L1 of the press-fit pin 38 is smaller than the diameter φ. The protruding end face of the press-fit pin 38 is a plane that extends perpendicular to the axis. Since the base end face of the base body 34 is an inner-side corresponding surface 36 that curves in the circumferential direction, the protruding length dimension of the press-fit pin 38 from the base body 34 gradually increases toward the center in the vertical direction. The maximum protruding length dimension L1 of the press-fit pin 38 is preferably less than or equal to the maximum front-to-back length dimension L2 (see Figure 7) in the vertical projection of the inner-side corresponding surface 36 in order to obtain the rotation limiting effect described later from the initial stage of press-fitting, and in this embodiment, it is approximately the same as the maximum front-to-back length dimension L2 in the vertical projection of the inner-side corresponding surface 36. However, the maximum protruding length dimension L1 of the press-fit pin 38 may be greater than the maximum front-to-back length dimension L2 in the upper and lower projection of the inner side corresponding surface 36.

[0063] As shown in Figures 7 and 8, the elastic section 32 has a laminated structure in which a rigid intermediate restraining member 44 is positioned between a tip elastic body 40 and an intermediate elastic body 42, both of which are made of elastic material. The entire elastic section 32 is made of a material that is harder than the main rubber elastic body 16. In particular, both the tip elastic body 40 and the intermediate elastic body 42 are made of an elastic material that is harder than the main rubber elastic body 16.

[0064] The tip elastic body 40 is a thin rubber layer that is superimposed on and fixed to the tip surface of the intermediate restraint member 44, and constitutes the tip surface of the stopper member 28. The tip elastic body 40 is made of a rubber material that is harder than the main rubber elastic body 16. The tip surface of the tip elastic body 40, which is the tip surface of the stopper member 28, is a smooth, continuous stopper contact surface 45 without holes. The tip elastic body 40 may also be made of a resin elastomer that exhibits rubber-like elasticity.

[0065] The intermediate elastic body 42 is a thin rubber layer that is superimposed on and fixed to the tip surface of the base body 34. The intermediate elastic body 42 is made of a rubber material that is harder than the main rubber elastic body 16. In this embodiment, the tip elastic body 40 and the intermediate elastic body 42 are made of the same elastic material, and manufacturing is facilitated by making it easier to mold the tip elastic body 40 and the intermediate elastic body 42 simultaneously. The intermediate elastic body 42 may also be made of a resin elastomer that exhibits rubber-like elasticity.

[0066] The intermediate restraint member 44 is plate-shaped and curved in correspondence with the tip surface of the base body 34, and is positioned at a distance from the tip side of the base body 34. An intermediate elastic body 42 is positioned between the opposing surfaces of the base body 34 and the intermediate restraint member 44, and the base body 34 and the intermediate restraint member 44 are interconnected by the intermediate elastic body 42. The tip surface of the intermediate restraint member 44 is almost entirely covered by a tip elastic body 40.

[0067] As shown in Figures 3 and 4, the stopper member 28, which has the structure described above, is fixed to the inner shaft member 12 by a press-fit pin 38. That is, with the press-fit pin 38 of the stopper member 28 positioned relative to the press-fit hole 24 of the inner shaft member 12, the stopper member 28 is brought close to the inner shaft member 12 from the front, causing the press-fit pin 38 to be pressed into the press-fit hole 24, thereby fixing the stopper member 28 to the inner shaft member 12 by pin press-fitting. As a result, the stopper member 28 is provided protruding forward from the inner shaft member 12. Note that the tip surface of the press-fit pin 38 and the bottom surface of the press-fit hole 24 are slightly separated, and the inner-side corresponding surface 36 of the base 30 of the stopper member 28 and the outer peripheral surface of the central shaft body 18 of the inner shaft member 12 are in contact and overlapping.

[0068] The stopper member 28 is fixed in place by press-fitting a press-fit pin 38 into the press-fit hole 24 of the inner shaft member 12. Therefore, compared to the case where the stopper member is bolted to the inner shaft member, for example, the fixing force of the stopper member 28, which is the pull-out resistance of the press-fit pin 38, can be set accurately and directly based on the press-fit resistance of the press-fit pin 38, thereby ensuring stable fixing.

[0069] In this embodiment, the press-fit pin 38 is integrally formed with the base 30 of the stopper member 28, thereby reducing the number of parts and facilitating the press-fitting operation.

[0070] In this embodiment, the outer circumferential surface of the central shaft body 18 in the inner shaft member 12 is a cylindrical surface that curves in the circumferential direction, and the overlapping surface (base end surface) of the base portion 30 of the stopper member 28 with the central shaft body 18 is an inner-side corresponding surface 36 that curves in the circumferential direction with a shape corresponding to the outer circumferential surface of the central shaft body 18. The outer circumferential surface of the central shaft body 18, which is the rotation limiting surface on the inner shaft member 12 side, and the inner-side corresponding surface 36, which is the rotation limiting surface on the stopper member 28 side, are overlapped with each other, thereby forming a rotation limiting mechanism that limits the relative amount of rotation of the stopper member 28 around the press-fit pin 38 with respect to the inner shaft member 12. This rotation limiting mechanism fixes the stopper member 28 in an appropriate orientation with respect to the inner shaft member 12 around the central axis of the press-fit pin 38. However, it is desirable that the stopper member 28 be positioned to some extent before the press-fit pin 38 is pressed in, so that the orientation of the press-fit pin 38 around the central axis is appropriate with respect to the inner shaft member 12.

[0071] The rotation limiting mechanism is designed to limit the relative amount of rotation of the stopper member 28 around the press-fit pin 38 with respect to the inner shaft member 12 during the initial stage of press-fitting the press-fit pin 38 into the press-fit hole 24. Therefore, in the initial stage of press-fitting, when the fixing force due to the press-fitting of the press-fit pin 38 is relatively small, the orientation of the stopper member 28 around the press-fit pin 38 with respect to the inner shaft member 12 is set by the rotation limiting mechanism, allowing the stopper member 28 to be attached in the appropriate orientation with respect to the inner shaft member 12. The initial stage of press-fitting the press-fit pin 38 refers, for example, to the stage when the press-fit length of the press-fit pin 38 into the press-fit hole 24 is 1 / 4 or less of the maximum length dimension L1 of the press-fit pin 38.

[0072] Both outer sections 14a and 14b have a curved plate shape that extends circumferentially for a length of less than half a circumference. Outer flanges 46, 46 that protrude outward are integrally formed at both axial ends of the outer sections 14a and 14b. The outer flanges 46 protrude outward while inclined axially outward, and are positioned opposite the inner flange 20 at a predetermined distance axially inward. One outer section 14a has a larger circumferential length than the other outer section 14b.

[0073] One of the outer sections 14a has a window portion 48 formed therein. The window portion 48 penetrates the central part of the outer section 14a in the circumferential and axial directions in the front-to-back direction and has a roughly square opening shape. In the axial beam rubber bush 10, the window portion 48 is larger than the tip surface of the stopper member 28 in the front-to-back projection, and is sized so that the entire tip surface of the stopper member 28 can be exposed through the window portion 48. The other outer section 14b does not have a through hole like the window portion 48.

[0074] The outer segments 14a and 14b are positioned separately on the outer circumference of the central shaft body 18 of the inner shaft member 12, and the inner shaft member 12 and the outer segments 14a and 14b are elastically connected to each other by the main rubber elastic body 16. The outer segments 14a and 14b are positioned radially opposite each other with the central shaft body 18 in between, and their circumferential ends are separated from each other.

[0075] The main rubber elastic body 16 has a generally thick, substantially cylindrical shape, and rubber flanges 50, 50 projecting outward are integrally formed at both axial ends. The inner circumferential surface of the cylindrical central axial portion of the main rubber elastic body 16 is vulcanized and bonded to the outer circumferential surface of the central shaft body 18 of the inner shaft member 12, while the outer circumferential surface is vulcanized and bonded to the inner circumferential surfaces of the outer segmented bodies 14a, 14b. Each rubber flange 50 is positioned between the opposing surfaces of the inner flange 20 of the inner shaft member 12 and the outer flanges 46, 46 of the outer segmented bodies 14a, 14b, and is vulcanized and bonded to the inner flange 20 and outer flanges 46, 46. In this embodiment, the main rubber elastic body 16 is formed as an integrally vulcanized molded product comprising the inner shaft member 12 and the outer segmented bodies 14a, 14b.

[0076] As shown in Figures 3 and 4, a pocket portion 52 is formed in the main rubber elastic body 16. The pocket portion 52 is a recess that opens on the outer circumferential surface of the main rubber elastic body 16 and is formed in the axial central portion of the main rubber elastic body 16. The outer circumferential surface of the main rubber elastic body 16 is fixed to the outer segment 14a around the opening of the pocket portion 52, and the window portion 48 of the outer segment 14a is positioned with the opening of the pocket portion 52, so that the pocket portion 52 is open to the outer circumferential surface through the window portion 48.

[0077] The stopper member 28 attached to the inner shaft member 12 protrudes into the pocket portion 52. The stopper member 28 is positioned in the central part of the pocket portion 52, and at least the elastic portion 32 is separated from the inner surface of the pocket portion 52 wall. The protruding tip surface of the stopper member 28 located inside the pocket portion 52 is exposed through the opening and window portion 48 of the pocket portion 52.

[0078] As shown in Figures 1 and 4, the main rubber elastic body 16 is exposed between the outer segments 14a and 14b in the circumferential direction, and a free surface is provided in the exposed portion that is not constrained by metal fittings or the like. An annular groove 54 is opened on the outer circumferential surface of the main rubber elastic body 16 that is exposed between the outer segments 14a and 14b in the circumferential direction, as shown in Figures 1 and 3. The annular groove 54 is composed of a transverse groove that extends axially along the circumferential ends of the outer segments 14a and 14b, and a circumferential groove that extends circumferentially along the base end of the rubber flange portion 50 of the main rubber elastic body 16, and extends continuously in a substantially rectangular annular shape in the exposed portion of the main rubber elastic body 16. The region of the main rubber elastic body 16 surrounded by the annular groove 54 is a protruding portion 56 that protrudes outward.

[0079] As shown in Figure 9, the axle beam rubber bush 10, with this structure, is attached to the bogie 58 of a railway vehicle. The bogie 58 comprises a bogie frame 60 and wheels 62. The axle box portion 66 that supports the axle 64 of the wheel 62 is elastically connected to the bogie frame 60 by an axle spring 68, and the axle beam 70 extends forward from the axle box portion 66. The housing portion 72 provided at the extended end of the axle beam 70 is connected to the bogie frame 60 by the axle beam rubber bush 10. Figure 9 shows the longitudinal and vertical directions of the railway vehicle. As can be seen from Figure 9, the longitudinal and vertical directions of the axle beam rubber bush 10 are approximately the same as the longitudinal and vertical directions of the railway vehicle.

[0080] In Figure 9, the front portion of the bogie 58 is omitted, but on both sides of the bogie frame 60 extending in the vehicle's longitudinal direction, axle box portions 66 are provided, and wheel support structures supporting wheels 62 are provided on each side. The front of the bogie 58 is provided with a wheel support structure that is substantially symmetrical to that in the vehicle's longitudinal direction in Figure 9. In this embodiment, the right side in Figure 9 is considered the front of the vehicle, but the left side in Figure 9 may also be the front of the vehicle. In that case, the stopper member 28 of the axle beam rubber bush 10 protrudes from the inner axle member 12 toward the rear of the vehicle.

[0081] More specifically, the roughly cylindrical housing portion 72 is constructed by fixing together roughly semi-cylindrical semi-tubular members 74a and 74b that face each other in the front-rear direction of the vehicle. The axle beam rubber bush 10 is fitted into the housing portion 72 in an inserted state, with the outer divided parts 14a and 14b sandwiched between the opposing semi-tubular members 74a and 74b.

[0082] The outer splits 14a and 14b are positioned such that the orientation of the axle beam rubber bushings 10 is set so that their opposing directions are the front and rear of the vehicle, and the semi-cylindrical members 74a and 74b are superimposed on the outer splits 14a and 14b from the outside in the opposing direction. In this way, because the housing portion 72 is a split structure composed of a front and rear pair of semi-cylindrical members 74a and 74b, the outer splits 14a and 14b can be attached to the housing portion 72 with simple work. In addition, the corners of the circumferential ends of the semi-cylindrical members 74a and 74b are prevented from contacting the outer circumferential surface of the outer splits 14a and 14b, thus preventing damage to the outer splits 14a and 14b due to galling.

[0083] The housing portion 72 is attached to the outer circumferential surfaces of the outer segment 14a and 14b, so that the window portion 48 of the outer segment 14a is covered by the semi-cylindrical member 74a of the housing portion 72. The semi-cylindrical member 74a of the housing portion 72 and the stopper member 28 attached to the inner shaft member 12 face each other in the front-rear direction at a predetermined distance apart.

[0084] On the other hand, the inner shaft member 12 of the shaft beam rubber bush 10 is attached to the bogie frame 60 by fastening bolts (not shown) that are inserted through bolt holes 26, with mounting portions 22 provided at both ends in the axial direction.

[0085] In this way, the inner axle member 12 of the axle beam rubber bush 10 is attached to the bogie frame 60, and the outer divided parts 14a and 14b are attached to the axle beam 70 on the axle box portion 66 side, so that the axle box portion 66 is elastically connected to the bogie frame 60 via the axle spring 68 and the axle beam rubber bush 10. Then, vertical vibrations input to the bogie frame 60 due to passengers getting on and off are absorbed by the axle spring 68. Furthermore, when the axle box portion 66 is displaced vertically with deformation of the axle spring 68, the oscillation of the axle beam 70 around the inner axle member 12 is permitted by the elastic deformation of the main rubber elastic body 16.

[0086] Furthermore, the axle beam rubber bush 10 is subjected to compressive and tensile loads in the longitudinal direction of the vehicle. However, a pair of outer segments 14a and 14b face each other in the longitudinal direction of the vehicle, and the compression and tension springs of the main rubber elastic body 16 act predominantly against inputs in the longitudinal direction of the vehicle. As a result, the durability of the main rubber elastic body 16 is improved, and relatively stiff spring characteristics are obtained due to the compression and tension springs. Therefore, by forming a window portion 48 in the outer segment 14a, the spring characteristics can be tuned with a large degree of freedom. When the railway vehicle is running, the stopper member 28 is held away from the inner circumference of the housing portion 72, so that linear spring characteristics are obtained due to the elastic deformation of the main rubber elastic body 16.

[0087] Incidentally, the bogie frame 60 is equipped with a brake device 76, which applies a brake shoe 78 to the outer surface of the wheel 62 from either the front or rear using hydraulic pressure or the like, thereby braking the rotation of the wheel 62. Thus, in the bogie 58 of this embodiment, the brake device 76 is a single-sided brake.

[0088] For example, when the brake shoe 78 is pressed against the wheel 62 from the front of the vehicle, a rearward force acts on the axle beam 70, causing the axle beam 70 to be displaced rearward, and the housing portion 72 provided on the axle beam 70 to be displaced rearward relative to the inner axle member 12. Then, the stopper member 28 fixed to the inner axle member 12 comes into contact with the semi-cylindrical member 74a of the housing portion 72 that covers the window portion 48 of the outer split body 14a, thereby limiting the amount of forward relative displacement of the inner axle member 12 with respect to the outer split bodies 14a and 14b fixed to the housing portion 72. This prevents excessive deformation of the main rubber elastic body 16 that connects the inner axle member 12 and the outer split bodies 14a and 14b, thereby improving durability.

[0089] Since the tip portion of the stopper member 28, including the contact surface with the housing portion 72, is an elastic portion 32, the shock sensation when the stopper member 28 and the housing portion 72 come into contact is adjusted by the elasticity of the elastic portion 32. In particular, in this embodiment, since the contact surface of the stopper member 28 with the housing portion 72 is made of an elastic tip 40, the reduction of impact noise and shock caused by the contact between the stopper member 28 and the housing portion 72 can be achieved more advantageously.

[0090] In this embodiment, the stopper member 28 has a laminated structure in which the elastic portion 32 is provided with a tip elastic body 40 and an intermediate elastic body 42 on both the front and rear sides of the intermediate restraint member 44. Therefore, by setting a large total thickness dimension of the tip elastic body 40 and the intermediate elastic body 42, durability can be improved, while adjusting the spring of the elastic portion 32 can achieve appropriate stopper characteristics.

[0091] The tip elastic body 40 and the intermediate elastic body 42 that constitute the elastic portion 32 are both made of a harder material than the main rubber elastic body 16. Therefore, sufficient durability of the tip elastic body 40 and the intermediate elastic body 42 is ensured in the stopper member 28, which is subjected to a large load due to the brake.

[0092] A press-fit pin 38 for fixing the stopper member 28 to the inner shaft member 12 is provided so as to protrude from the base 30 of the stopper member 28 toward the inner shaft member 12, and the tip surface of the stopper member 28, which is composed of a tip elastic body 40, is a stopper contact surface 45 which is a smoothly continuous curved surface without holes. Therefore, the contact area between the tip surface of the stopper member 28 and the inner circumferential surface of the housing portion 72 can be efficiently increased, and the durability of the tip elastic body 40 can be improved by distributing stress.

[0093] The maximum protrusion length L1 of the press-fit pin 38 from the base 30 is set to be greater than the difference D between the diameter of the outer circumferential surface of the outer segment 14a when mounted on the housing 72 and the diameter of the tip surface of the stopper member 28. In other words, the maximum protrusion length L1 of the press-fit pin 38 from the base 30 is set to be greater than the distance D between the opposing surfaces of the tip surface of the stopper member 28 and the inner circumferential surface of the housing 72. Therefore, even if the press-fit pin 38 of the stopper member 28 tries to come out of the press-fit hole 24 of the inner shaft member 12, the displacement of the stopper member 28 in the direction of removal is limited by the contact between the stopper member 28 and the housing 72 before the press-fit pin 38 completely comes out of the press-fit hole 24, thereby preventing the stopper member 28 from separating from the inner shaft member 12.

[0094] Figures 10 and 11 show a shaft beam rubber bush 80 as a cylindrical elastic coupling device for shaft beams according to a second embodiment of the present invention. The shaft beam rubber bush 80 has a structure in which an intermediate member 84 is interposed between an inner shaft member 12 and a stopper member 82. In the following description, components and parts that are substantially the same as those in the first embodiment are denoted by the same reference numerals in the figures and their descriptions are omitted.

[0095] The stopper member 82 has a base end surface of the base body 88 at the base portion 86 that is a plane that extends substantially perpendicular to the press-fit pin 38, and is not a curved surface like the inner corresponding surface 36 in the first embodiment. In addition, a regulating recess 90 opens at the base end surface of the base body 88 of the stopper member 82. The regulating recess 90 is a bottomed recess with a rectangular cross-section corresponding to the regulating wall portion 98 which will be described later, and is located to the right of the press-fit pin 38.

[0096] The intermediate member 84 is a highly rigid member made of a metal such as iron or an aluminum alloy. As shown in Figures 12 and 13, the intermediate member 84 is generally rectangular in shape and has a pin insertion hole 92 that penetrates in the thickness direction of the plate. The pin insertion hole 92 is a circular hole with a larger diameter than the press-fit pin 38, so that the press-fit pin 38 can be inserted without being pressed in.

[0097] The intermediate member 84 has a base end surface, which is the overlapping surface with the central shaft body 18 of the inner shaft member 12, and is an inner-side corresponding surface 94 that curves in the circumferential direction corresponding to the outer circumferential surface of the cylindrical central shaft body 18. The intermediate member 84 has a tip surface, which is the overlapping surface with the base body 88 of the stopper member 82, and is a stopper-side corresponding surface 96 that is composed of a plane that extends in a direction perpendicular to the press-fit pin 38, corresponding to the base end surface of the base body 88. Therefore, the intermediate member 84 gradually becomes thicker towards both sides in the circumferential direction of the inner shaft member 12. The pin insertion hole 92 that penetrates the intermediate member 84 is open in the inner-side corresponding surface 94 and the stopper-side corresponding surface 96, respectively.

[0098] The intermediate member 84 is provided with a restricting wall portion 98 that protrudes from the stopper-side corresponding surface 96 toward the front side, which is the stopper member 82 side. The restricting wall portion 98 is rectangular prism-shaped and is located to the right of the pin insertion hole 92. However, the protruding position of the restricting wall portion 98 on the stopper-side corresponding surface 96 is not particularly limited, and it is sufficient that the restricting wall portion 98 can be inserted into the restricting recess 90 when the stopper member 82 and the intermediate member 84 are superimposed, as will be described later.

[0099] The intermediate member 84 is positioned between the inner shaft member 12 and the base body 88 of the stopper member 82. More specifically, with the stopper-side corresponding surface 96 of the intermediate member 84 superimposed on the base end surface of the base body 88 of the stopper member 82, the press-fit pin 38 of the stopper member 82, which is inserted through the pin insertion hole 92 of the intermediate member 84 without press-fitting, is press-fitted and fixed into the press-fit hole 24 of the inner shaft member 12. As a result, the stopper member 82 is fixed to the inner shaft member 12 by pin press-fitting, and the intermediate member 84 is interposed between the stopper member 82 and the inner shaft member 12. The inner-side corresponding surface 94 of the intermediate member 84 superimposed on the outer circumferential surface of the central shaft body 18 of the inner shaft member 12 around the press-fit hole 24.

[0100] The restricting wall portion 98 of the intermediate member 84 is inserted into the restricting recess 90 of the stopper member 82, and the contact and locking between the restricting wall portion 98 and the inner surface of the restricting recess 90 constitutes a first rotation limiting portion that limits the relative amount of rotation between the stopper member 82 and the intermediate member 84 around the press-fit pin 38. Furthermore, the outer circumferential surface of the central shaft body 18 of the inner shaft member 12 is a cylindrical surface that is curved in the circumferential direction, and the inner-side corresponding surface 94 of the intermediate member 84 is a curved surface that corresponds to the outer circumferential surface of the central shaft body 18, and the outer circumferential surface of the central shaft body 18 and the inner-side corresponding surface 94 of the intermediate member 84 are superimposed to constitute a second rotation limiting portion that limits the relative amount of rotation of the intermediate member 84 with respect to the inner shaft member 12 around the press-fit pin 38. Then, the cooperation of the first rotation limiting portion and the second rotation limiting portion constitutes the rotation limiting mechanism of this embodiment that limits the relative amount of rotation between the stopper member 82 and the inner shaft member 12 around the press-fit pin 38.

[0101] Furthermore, the rotation limiting mechanism of this embodiment, similar to the rotation limiting mechanism of the first embodiment, exhibits a rotation limiting effect that restricts the relative amount of rotation between the stopper member 82 and the inner shaft member 12 around the press-fit pin 38 during the initial stage of press-fitting the press-fit pin 38.

[0102] The rubber bushing 80 for the shaft beam, equipped with such an intermediate member 84, can be expected to have the same effects as the rubber bushing 10 for the shaft beam in the first embodiment. Furthermore, for example, when changing the outer diameter dimension or outer surface shape of the central shaft body 18 of the inner shaft member 12, simply changing the shape and size of the intermediate member 84 to match the central shaft body 18 eliminates the need to redesign the base 86 of the stopper member 82. Therefore, it becomes unnecessary to prepare new molding dies for the tip elastic body 40 and the intermediate elastic body 42 in accordance with changes to the base of the stopper member 82, and the central shaft body 18 can easily accommodate multiple types of inner shaft members 12 that are different from each other.

[0103] The specific structure of the intermediate member is not limited to those illustrated in Figures 10 to 13. Specifically, for example, the intermediate member 100 shown in Figures 14 to 16 can also be used. As shown in Figures 15 and 16, the intermediate member 100 is in the shape of a roughly rectangular plate, and the vertical width dimension of the front end surface that overlaps with the stopper member 104 is larger than the vertical width dimension of the base end surface that overlaps with the inner shaft member 12. The intermediate member 100 has a pin insertion hole 92 that penetrates through the center in the thickness direction of the plate. The front end surface of the intermediate member 100 has a groove 102 that extends linearly in the left-right direction from the central part in the vertical direction, and the side walls (upper and lower walls) of the groove 102 are the regulating walls of this embodiment. The pin insertion hole 92 opens to the bottom surface of the groove 102.

[0104] As shown in Figure 14, the intermediate member 100 is interposed between the inner shaft member 12 and the stopper member 104, similar to the intermediate member 84 in the second embodiment. The stopper member 104 in this embodiment has an engaging projection 108 that protrudes from the base end face of the base body 106 and can be inserted into the groove 102 of the intermediate member 100. The engagement of the engaging projection 108 of the stopper member 104 with the side wall portion of the groove 102 in the intermediate member 100 constitutes a first rotation limiting portion that limits the relative amount of rotation between the stopper member 104 and the intermediate member 100 around the press-fit pin 38.

[0105] Figures 17 and 18 show a rubber bushing 110 for a axial beam, which is a cylindrical elastic coupling device for an axial beam according to a third embodiment of the present invention. The rubber bushing 110 for the axial beam includes a stopper member 112. The stopper member 112 has a structure in which an elastic portion 118 is provided on the tip side of a base portion 114 equipped with a press-fit pin 38.

[0106] The base portion 114 has a structure in which a press-fit pin 38 protrudes from the base body 116 toward the base end. The base body 116 has a recess 120 that opens on its tip surface. In this embodiment, the base portion 114 is a pressed metal fitting, and for example, by press-forming the central portion of a metal sheet to protrude toward the base end, the press-fit pin 38 can be formed, and a base portion 114 can be obtained that integrally comprises the base body 116 and the press-fit pin 38.

[0107] The elastic portion 118 has a single-layer structure and is entirely made of an elastic material. The elastic portion 118 is curved in shape and is fixed to the tip surface of the base portion 114. The elastic portion 118 has a circular hole 122 that penetrates through the central part in the thickness direction, and the recess 120 of the base body 116 is open to the front through the circular hole 122. The recess 120 of the base body 116 and the circular hole 122 of the elastic portion 118 constitute the tip opening hole 124 of this embodiment, which opens to the tip surface of the stopper member 112.

[0108] With this type of stopper member 112, the tip opening 124 is provided on the tip surface of the stopper member 112 that contacts the inner circumferential surface of the housing portion 72, allowing the contact area and contact location between the stopper member 112 and the housing portion 72 to be adjusted by the tip opening 124.

[0109] Figures 19 and 20 show a rubber bushing 130 for a axial beam, which is a cylindrical elastic coupling device for an axial beam according to the fourth embodiment of the present invention. The rubber bushing 130 for the axial beam is equipped with a stopper member 132. The stopper member 132 has a structure in which an elastic portion 136 is provided on the tip side of a rigid base portion 134.

[0110] The base portion 134 is plate-shaped and curves in the circumferential direction of the inner shaft member 12. A pin insertion hole 138 is formed in the central part of the base portion 134, penetrating in the thickness direction of the plate. The tip end of the pin insertion hole 138 is made larger in diameter, thereby forming a stepped seating surface 140 around its entire circumference. The base end surface of the base portion 134 is a curved surface that corresponds to the outer circumferential surface of the central shaft body 18 of the inner shaft member 12, and is the same inner side corresponding surface 36 as in the first embodiment.

[0111] Similar to the first embodiment, the elastic portion 136 has a laminated structure in which a rigid intermediate restraining member 146 is fixed between a tip elastic body 142 and an intermediate elastic body 144, both made of an elastic material. The elastic portion 136 of this embodiment is provided with a tip open hole 148 that penetrates in the lamination direction. The tip open hole 148 is connected in series with a pin insertion hole 138 of the base portion 134, and the pin insertion hole 138 is open to the tip side through the tip open hole 148.

[0112] The stopper member 132 has a base 134 that is fixed to the inner shaft member 12 by a separate press-fit pin 150. The press-fit pin 150 comprises a shaft portion 152 that is press-fitted into the press-fit hole 24 of the inner shaft member 12, and a head portion 154 that has a larger diameter than the shaft portion 152. The shaft portion 152 of the press-fit pin 150 has a smaller diameter than the small-diameter portion of the pin insertion hole 138 in the base 134 of the stopper member 132, and is able to be inserted into the pin insertion hole 138 without press-fitting. The head 154 of the press-fit pin 150 has a larger diameter than the smaller diameter portion of the pin insertion hole 138, and a smaller diameter than the larger diameter portion (tip portion) of the pin insertion hole 138 and the tip opening hole 148 in the elastic portion 136 of the stopper member 132, allowing it to be inserted into the tip portion of the pin insertion hole 138 and the tip opening hole 148 without press-fitting.

[0113] Then, the shaft portion 152 of the press-fit pin 150, which is inserted from the tip side into the tip open hole 148 of the stopper member 132, is inserted through the pin insertion hole 138 of the stopper member 132 without press-fitting, and is press-fitted into the press-fit hole 24 of the inner shaft member 12, thereby pin-press-fitting the stopper member 132 to the inner shaft member 12 with the press-fit pin 150. The head portion 154 of the press-fit pin 150, which is press-fitted to the inner shaft member 12, is in contact with the seating surface 140 of the pin insertion hole 138 and is superimposed on it, so that the stopper member 132 does not move toward the tip side relative to the inner shaft member 12.

[0114] As shown in this embodiment, the press-fit pin for fixing the stopper member to the inner shaft member is not limited to being integrally provided with the stopper member, but may be separate from the stopper member and the inner shaft member.

[0115] Figures 21 and 22 show a rubber bushing 160 for a shaft beam as a cylindrical elastic coupling device for a shaft beam according to the fifth embodiment of the present invention. The rubber bushing 160 for a shaft beam has a structure in which a stopper member 164 is attached to an inner shaft member 162.

[0116] As shown in Figure 23, the inner shaft member 162 has a stopper mounting surface 166 formed around the press-fit hole 24 in the central shaft body 165, which is a flat surface. The stopper mounting surface 166 extends perpendicular to the front-rear direction and is provided in a notched shape in the axial central portion of the cylindrical central shaft body 165. Due to the formation of the stopper mounting surface 166, a part of the outer surface of the central shaft body 165 has a groove-like shape with the stopper mounting surface 166 as its bottom surface, and the side walls of this groove-like portion are the rotation limiting portions 168, 168 of this embodiment.

[0117] As shown in Figures 21 and 22, the stopper member 164 has a structure in which an elastic portion 32 is provided on the tip side of a rigid base portion 170. The base portion 170 is plate-shaped, with the base end surface being an inner-side corresponding surface 172 composed of a plane substantially perpendicular to the front-rear direction, and the tip surface being a convex curved surface that protrudes forward toward the center in the vertical direction. The base portion 170 has a stopper-side press-fit hole 174 that opens into the inner-side corresponding surface 172. The stopper-side press-fit hole 174 has substantially the same hole cross-sectional shape and hole diameter as the press-fit hole 24 of the inner shaft member 162. In this embodiment, the stopper-side press-fit hole 174 is deeper than the press-fit hole 24 of the inner shaft member 162. However, the stopper-side press-fit hole 174 and the press-fit hole 24 of the inner shaft member 162 may be of the same depth, or the stopper-side press-fit hole 174 may be shallower than the press-fit hole 24 of the inner shaft member 162.

[0118] The stopper member 164 is fixed to the inner shaft member 162 by a press-fit pin 176. The press-fit pin 176 is axial in shape, extending with a substantially constant cross-sectional shape and outer diameter, for example, being cylindrical. One end of the press-fit pin 176 is press-fitted and fixed into the press-fit hole 24 of the inner shaft member 162, and the other end is press-fitted and fixed into the stopper-side press-fit hole 174 of the stopper member 164. For example, the stopper member 164 and the inner shaft member 162 can be fixed by the press-fit pin 176 by first press-fitting the other end of the press-fit pin 176 into the stopper-side press-fit hole 174, and then press-fitting the one end of the press-fit pin 176 that protrudes from the stopper member 164 towards the base end into the press-fit hole 24 of the inner shaft member 162.

[0119] With the stopper member 164 fixed to the inner shaft member 162 by the press-fit pin 176, the inner-side corresponding surface 172 is superimposed on the stopper mounting surface 166 of the inner shaft member 162. The inner-side corresponding surface 172 of the stopper member 164 is a flat surface, which facilitates the manufacturing of the base portion 170 of the stopper member 164.

[0120] The left and right sides of the base 170 of the stopper member 164 are superimposed on the rotation limiting portions 168, 168 of the inner shaft member 162. The amount of relative rotation of the stopper member 164 with respect to the inner shaft member 162 around the press-fit pin 176 is limited by a rotation limiting mechanism formed by the locking of the base 170 of the stopper member 164 and the rotation limiting portions 168, 168 of the inner shaft member 162. As a result, even if the overlapping surfaces of the stopper member 164 and the inner shaft member 162 are both flat, the stopper member 164 can be mounted in the correct orientation around the press-fit pin 176 with respect to the inner shaft member 162. In this embodiment, the front-to-back height dimension of the rotation limiting portions 168, 168 of the inner shaft member 162 is set to be approximately the same as the press-fit length dimension of the press-fit pin 176 into the press-fit hole 24, so that the rotation limiting effect is exerted from the initial stage of press-fitting the press-fit pin 176 into the press-fit hole 24. However, the front-to-back height dimension of the rotation limiting portions 168, 168 of the inner shaft member 162 may be larger or smaller than the press-fit length dimension of the press-fit pin 176 into the press-fit hole 24.

[0121] Although embodiments of the present invention have been described in detail above, the present invention is not limited by its specific description. For example, the press-fit pin may be provided on the inner shaft member side, the press-fit pin may be integrally formed so as to protrude from the outer circumferential surface of the inner shaft member, or a separate press-fit pin may be fixed to the inner shaft member.

[0122] The press-fit pin is not limited to one; for example, using multiple pins can prevent rotation of the stopper member around the press-fit pin relative to the inner shaft member. The press-fit pin may be positioned off-center from the center of the stopper member. The press-fit pin is not limited to a circular cross-section.

[0123] It is also possible to provide an air venting structure to release air from inside the press-fit hole to the outside when the press-fit pin is pressed in. By providing an air venting structure, it is possible to prevent the air inside the press-fit hole from being compressed by the press-fit pin, thereby preventing improper press-fitting or detachment of the press-fit pin due to the action of an air spring. The air venting structure is not particularly limited, but can be realized, for example, by forming an axial groove on at least one of the outer surface of the press-fit pin and the inner surface of the press-fit hole, or by forming a hole that opens in the bottom wall of the press-fit hole and penetrates the inner shaft member.

[0124] In the second embodiment, an example was shown in which a regulating wall portion 98 provided on the intermediate member 84 is inserted into a regulating recess 90 provided on the base portion 86 of the stopper member 82, and the regulating wall portion 98 is locked to the inner circumferential surface of the regulating recess 90, thereby forming a first rotation limiting portion that limits the relative amount of rotation between the stopper member 82 and the intermediate member 84. However, for example, the regulating wall portion 98 of the intermediate member 84 may be locked to the outer circumferential surface of the stopper member 82 to form the first rotation limiting portion. This eliminates the need to form a regulating recess 90 on the base portion 86 of the stopper member 82, and the structure of the stopper member 82 can be further simplified. The regulating wall portion 98 can be positioned at the outer circumferential end of the intermediate member 84. Alternatively, a regulating wall portion can be provided that protrudes from the stopper member toward the intermediate member, and the regulating wall portion may be locked to the intermediate member to form the first rotation limiting portion.

[0125] 10 Rubber bushing for axle beam (cylindrical elastic coupling device for axle beam in the first embodiment) 12 Inner axle member 14a, 14b Outer split body 16 Main rubber elastic body 18 Central axle body 20 Inner flange 22 Mounting part 24 Press-fit hole 26 Bolt hole 28 Stopper member 30 Base part 32 Elastic part 34 Base body 36 Inner side corresponding surface 38 Press-fit pin 40 Tip elastic body 42 Intermediate elastic body 44 Intermediate restraining member 45 Stopper contact surface 46 Outer flange 48 Window part 50 Rubber flange 52 Pocket part 54 Annular groove 56 Protruding part 58 Bogie 60 Bogie frame 62 Wheel 64 Axle 66 Axle box part 68 Axle spring 70 Axle beam 72 Housing portion 74a, 74b Semi-cylindrical member 76 Brake device 78 Brake shoe 80 Rubber bushing for shaft beam (cylindrical elastic coupling device for shaft beam in the second embodiment) 82 Stopper member 84 Intermediate member 86 Base portion 88 Base portion body 90 Restricting recess (first rotation limiting portion) 92 Pin insertion hole 94 Inner side corresponding surface (second rotation limiting portion) 96 Stopper side corresponding surface 98 Restricting wall portion (first rotation limiting portion) 100 Intermediate member (another embodiment) 102 Groove (first rotation limiting portion) 104 Stopper member 106 Base portion body 108 Engaging projection (first rotation limiting portion) 110 Rubber bushing for shaft beam (cylindrical elastic coupling device for shaft beam in the third embodiment) 112 Stopper member 114 Base portion 116 Base portion body 118 Elastic portion 120 122 Recess Circular hole 124 Open tip hole 130 Rubber bushing for shaft beam (Fourth embodiment cylindrical elastic coupling device for shaft beam) 132 Stopper member 134 Base 136 Elastic part 138 Pin insertion hole 140 Seat surface 142 Tip elastic body 144 Intermediate elastic body 146 Intermediate restraining member 148 Open tip hole 150 Press-fit pin 152 Shaft part 154 Head 160 Rubber bushing for shaft beam (Fifth embodiment cylindrical elastic coupling device for shaft beam) 162 Inner shaft member 164 Stopper member 165 Central shaft body 166 Stopper mounting surface 168 Rotation limiting part 170 Base 172 Inner side corresponding surface 174 Stopper side press-fit hole 176 Press-fit pin

Claims

1. In a cylindrical elastic coupling device for an axle beam, an inner axle member is provided with a set of outer segments arranged on the outer circumference of the inner axle member, facing each other in a direction perpendicular to the axis, and the inner axle member and the set of outer segments are elastically connected to each other by a main rubber elastic body, the inner axle member is attached to the bogie frame of a railway vehicle, and the set of outer segments is attached to a cylindrical housing portion provided at one end of the axle beam, thereby elastically connecting the bogie frame and the axle beam, the inner axle member is provided with a stopper member that limits the relative displacement between the inner axle member and the set of outer segments in either the front-rear direction of the railway vehicle by contact with the housing portion, the stopper member has a rigid base portion fixed to the inner axle member, and the stopper member has an elastic portion fixed to the base portion, with the end surface of the stopper member opposite to the inner axle member being made of an elastic material, A cylindrical elastic coupling device for a shaft beam, wherein the inner shaft member and the base of the stopper member are fixed to each other by a press-fit pin.

2. The tip surface of the stopper member that contacts the housing portion is a smoothly continuous stopper contact surface, as described in claim 1.

3. The cylindrical elastic coupling device for an axial beam according to claim 1, wherein the stopper member has an open tip hole formed on the tip surface that contacts the housing portion.

4. The cylindrical elastic coupling device for a shaft beam according to claim 3, wherein the press-fit pin, which is separate from the inner shaft member and the stopper member, is press-fitted into the inner shaft member from the tip side of the stopper member through the tip opening hole, thereby fixing the inner shaft member and the stopper member to each other.

5. The cylindrical elastic coupling device for an axial beam according to any one of claims 1 to 3, wherein the press-fit pin is integrally formed with the stopper member.

6. The cylindrical elastic coupling device for a shaft beam according to any one of claims 1 to 4, wherein the press-fit pin is separate from the inner shaft member and the stopper member and is press-fitted into the inner shaft member and the stopper member, respectively.

7. The cylindrical elastic coupling device for a shaft beam according to any one of claims 1 to 4, wherein a rotation limiting mechanism is provided to limit the relative amount of rotation of the stopper member with respect to the inner shaft member around the press-fit pin.

8. The cylindrical elastic coupling device for a shaft beam according to claim 7, wherein the overlapping surface of the inner shaft member and the stopper member is a rotation-restricting surface that curves in the circumferential direction of the inner shaft member, and the rotation-restricting mechanism is configured by the overlapping of the rotation-restricting surfaces.

9. The cylindrical elastic coupling device for a shaft beam according to claim 7, wherein the rotation limiting mechanism includes a rotation limiting portion that limits the amount of relative rotation of the stopper member around the press-fit pin with respect to the inner shaft member by engaging with the stopper member.

10. The cylindrical elastic coupling device for a shaft beam according to claim 7, wherein the rotation limiting mechanism exhibits a rotation limiting effect that limits the amount of relative rotation of the stopper member with respect to the inner shaft member during the initial stage of press-fitting the press-fit pin.

11. An intermediate member is provided, wherein one surface is an inner-side corresponding surface superimposed on the outer circumferential surface of the inner shaft member, and the other surface is a stopper-side corresponding surface superimposed on the inner shaft member side surface of the stopper member, the intermediate member has a pin insertion hole formed therethrough that opens to the inner-side corresponding surface and the stopper-side corresponding surface, the intermediate member is disposed between the inner shaft member and the stopper member, and the stopper member is fixed to the inner shaft member by the press-fit pin inserted through the pin insertion hole of the intermediate member without press-fitting.

12. The cylindrical elastic coupling device for a shaft beam according to claim 11, wherein a first rotation limiting portion is provided to limit the amount of relative rotation of the stopper member with respect to the intermediate member around the press-fit pin, and a second rotation limiting portion is provided to limit the amount of relative rotation of the intermediate member with respect to the inner shaft member around the press-fit pin, and the rotation limiting mechanism for limiting the amount of relative rotation of the stopper member with respect to the inner shaft member is configured by the cooperation of the first rotation limiting portion and the second rotation limiting portion.

13. The cylindrical elastic coupling device for a shaft beam according to claim 12, wherein the first rotation limiting portion includes a restricting wall portion that protrudes toward the stopper member and limits the relative amount of rotation of the stopper member with respect to the intermediate member around the press-fit pin by engaging with the stopper member, and the second rotation limiting portion is configured such that the inner side corresponding surface of the intermediate member, which is curved in the circumferential direction of the inner shaft member, is superimposed on the inner shaft member.

14. The cylindrical elastic coupling device for a shaft beam according to claim 12, wherein the rotation limiting mechanism exhibits a rotation limiting effect that limits the amount of relative rotation of the stopper member with respect to the inner shaft member during the initial stage of press-fitting the press-fit pin.

15. The cylindrical elastic coupling device for axial beams according to any one of claims 1 to 4, wherein the elastic part is made of a material harder than the main body rubber elastic body.

16. The cylindrical elastic coupling device for an axial beam according to any one of claims 1 to 4, wherein the elastic portion of the stopper member is a laminated structure comprising a tip elastic body constituting the tip surface of the stopper member, an intermediate elastic body fixed to the tip side of the base, and a rigid intermediate restraining member disposed between the tip elastic body and the intermediate elastic body.

17. The cylindrical elastic coupling device for an axial beam according to claim 16, wherein the tip elastic body and the intermediate elastic body are formed of the same elastic material.

18. The cylindrical elastic coupling device for a shaft beam according to any one of claims 1 to 4, wherein the press-fit pin protrudes from the stopper member toward the inner shaft member, and the maximum protruding length of the press-fit pin from the stopper member is greater than the difference between the diameter of the outer peripheral surface of the pair of outer divisions in the housing and the diameter of the tip surface of the stopper member.

19. The cylindrical elastic coupling device for an axial beam according to any one of claims 1 to 4, wherein at least one of the pair of outer divided bodies has a window portion that penetrates radially, and the stopper member is exposed through the window portion.

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