JP2020012527A - Cab mount - Google Patents

Abstract

To provide a cab mount of a novel structure which can stably exercise a predetermined vibration-proof effect even when relative positions of an inner shaft member and a vehicle frame are shifted.SOLUTION: In a cab mount 10 in which an upper elastic body 18 and a lower elastic body 20 are installed in an inner shaft member 16 that is inserted in a mounting hole 50 of a vehicle frame 12 and is fitted to a vehicle cabin 14 and which performs vibration isolating connection with the vehicle cabin 14 having the vehicle frame 12 in between in a shaft direction between an upper plate 28 and a lower plate 42 provided on both sides in the axial direction of the inner shaft member 16 via the upper elastic body 18 and the lower elastic body 20, an intermediate elastic body 62 positioned between facing surfaces in a shaft perpendicular direction of the inner shaft member 16 and the vehicle frame 12 is provided on an outer peripheral surface of the shaft direction intermediate part of the inner shaft member 16 as a separate member of the upper elastic body 18 and the lower elastic body 20, and the intermediate elastic body 62 is composed of a foaming elastic body.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cab mount for supporting a vehicle cabin (cab) of an automobile in a vibration-proof manner with respect to a vehicle frame.

  2. Description of the Related Art Conventionally, automobiles such as sports utility vehicles (SUVs) and trucks have often adopted a frame structure. A structure in which a vehicle cabin is supported by a cab mount on a vehicle frame mounted with running wheels by a suspension mechanism by a suspension mechanism. have.

  As such a cab mount, a sandwich type structure described in JP-A-2004-291795 (Patent Document 1) and the like is known. That is, the inner shaft member is inserted into a mounting hole formed in the vehicle frame, and the upper elastic body and the lower elastic body are externally fitted to the inner shaft member on both axial sides of the vehicle frame. Then, one of the upper elastic body and the lower elastic body is compressed and deformed by the relative displacement of the vehicle cabin and the vehicle frame in the approaching or separating direction (bound direction or rebound direction), so that the vibration damping effect is exerted. It has become.

  Here, the present inventors have found that when such a cab mount is mounted on a vehicle, the intended anti-vibration effect may not be sufficiently exhibited. As a result of repeated examinations, the reasons why the anti-vibration effect is not sufficiently exhibited are as follows: variations in the assembly position between the vehicle frame on which the cab mount is mounted and the vehicle cabin, and tolerances of each component such as mounting holes and fixing bolts. Further, it has been found that the inner shaft member of the cab mount and the mounting hole of the vehicle frame are relatively displaced in a direction perpendicular to the axis due to an assembly error or the like.

  That is, in the cab mount, as shown in the above Patent Document 1, the inner peripheral portion of the upper elastic body or the lower elastic body extends into the mounting hole of the vehicle frame, and connects the vehicle frame to the inner shaft member. A small-diameter cylindrical portion is provided between the opposing surfaces in the direction perpendicular to the axis so as to exhibit anti-vibration performance in the direction perpendicular to the axis. However, since such a small-diameter cylindrical portion is disposed between the mounting holes of the vehicle frame and the radially opposed surfaces of the outer peripheral surface of the inner shaft member, it is difficult to set the dimension in the direction perpendicular to the axis large, Due to the difficulty in setting the clearance space for deformation, if the inner shaft member and the mounting hole of the vehicle frame are displaced relative to each other in the direction perpendicular to the axis when mounting the cab mount, the spring characteristics will suddenly increase. It becomes big. Therefore, the relative position in the direction perpendicular to the axis between the mounting hole of the vehicle frame and the inner shaft member varies due to the variation in the mounting position of the vehicle frame and the vehicle cabin as described above, the tolerance of each component, and the like. In this case, the spring characteristics in the direction perpendicular to the axis greatly changed, and it was difficult to stably obtain the target vibration isolation performance.

JP-A-2004-291795

  Here, the present invention has been made in view of the above circumstances, and a problem to be solved is to prevent the inner shaft member from being displaced with respect to the mounting hole of the vehicle frame when mounted on the vehicle. An object of the present invention is to provide a cab mount having a novel structure capable of suppressing a reduction in vibration performance.

  According to a first aspect of the present invention, an upper elastic body and a lower elastic body are mounted on an inner shaft member that is inserted into a mounting hole of a vehicle frame and mounted on a vehicle cabin, and the axial direction of the inner shaft member is In a cab mount, the vehicle frame is axially sandwiched between an upper plate and a lower plate provided on both sides of the vehicle frame via the upper elastic body and the lower elastic body so as to be vibration-isolated to the vehicle cabin. On the outer peripheral surface of the axially intermediate portion of the shaft member, an intermediate elastic body positioned between opposing surfaces of the inner shaft member and the vehicle frame in a direction perpendicular to the axis is separate from the upper elastic body and the lower elastic body. It is provided as a member, and the intermediate elastic body is constituted by a foamed elastic body.

  According to the cab mount having the structure according to this aspect, since the intermediate elastic body is separate from the upper elastic body and the lower elastic body, a large degree of freedom in selecting the material and the like of the intermediate elastic body is ensured. . In particular, since the intermediate elastic body is formed of a foamed elastic body, an increase in the spring constant during a load action can be reduced as compared with a non-foamed elastic body, and the relief space at the time of deformation is set around the elastic body. Even if it cannot be ensured, it is possible to avoid a remarkably high dynamic spring when a load is applied. Therefore, even when the mounting hole of the vehicle frame is displaced from the inner shaft member when the cab mount is mounted, a significant decrease in the vibration isolation characteristics is avoided, and the desired vibration isolation effect can be stably obtained. You can do it.

  In addition, the material of the foamed elastic body according to the present invention is not limited at all, but the following aspects are preferably adopted. That is, a second aspect of the present invention is the cab mount according to the first aspect, wherein the intermediate elastic body is made of urethane foam.

  According to a third aspect of the present invention, in the cab mount according to the first or second aspect, the intermediate elastic body is formed in a continuous annular shape in a circumferential direction, and is temporarily fixed by external fitting to the inner shaft member. It is something that has become.

  According to the cab mount having the structure according to this aspect, it is possible to temporarily fix the cab mount to the inner shaft member and integrally handle the cab mount before assembling to the vehicle.

  A fourth aspect of the present invention is the cab mount according to any one of the first to third aspects, wherein the vehicle frame has an axis perpendicular to an outer peripheral surface of an axially intermediate portion of the inner shaft member. A cylindrical portion is provided extending in the axial direction so as to face each other in the direction, and the intermediate elastic body is located on the inner peripheral side of the cylindrical portion and is disposed over the entire length in the axial direction of the cylindrical portion. Things.

  According to the cab mount having the structure according to this aspect, it is easy to increase the area of the surface facing the inner shaft member in the direction perpendicular to the axis in the mounting hole of the vehicle frame, and thus the axial size or volume of the intermediate elastic body. Becomes In this embodiment, the tubular portion provided on the vehicle frame does not need to be formed integrally with the vehicle frame, but may be formed by, for example, another member fixed to a mounting hole of the vehicle frame.

  According to the cab mount having the structure according to the present invention, since the foamed elastic body is disposed between the vehicle frame and the inner shaft member in the direction perpendicular to the axis, the inner shaft member is displaced from the predetermined position with respect to the vehicle frame. Even so, the influence on the spring characteristics is reduced, and the desired anti-vibration characteristics can be stably exhibited.

FIG. 1 is a perspective view showing a cab mount as one embodiment of the present invention in a state of being mounted on a vehicle frame. FIG. 2 is a longitudinal sectional view of the cab mount shown in FIG. 1. FIG. 2 is a perspective view showing a state in which an integrally vulcanized molded product of an upper elastic body, an inner shaft member, and an intermediate elastic body that constitute the cab mount shown in FIG. 1 are assembled. 7 is a graph showing the relationship between the amount of displacement between the inner shaft member and the vehicle frame in the vehicle longitudinal direction and the dynamic spring constant, and is a graph showing a comparison between the example and the comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, FIGS. 1 and 2 show a cab mount 10 for an automobile according to an embodiment of the present invention mounted on a vehicle frame 12. The cab mount 10 has an inner shaft member 16 attached to the vehicle cabin 14, an upper elastic member 18 made of a rubber elastic member attached to the inner shaft member 16, and a lower elastic member 20. The cab mount 10 is interposed between the vehicle cabin 14 and the vehicle frame 12, so that the vehicle cabin 14 is elastically supported (vibration-proof connected) to the vehicle frame 12. It has become. In the following description, the up-down direction and the axial direction refer to the up-down direction in FIG. 2 that is the up-down direction when the vehicle is mounted on a vehicle and the center axis direction of the inner shaft member 16. Further, the front-rear direction refers to the left-right direction in FIG. 2 that is the front-rear direction when mounted on the vehicle, while the left-right direction is the left-right direction when the vehicle is mounted on the vehicle. Refers to the direction. Here, in FIG. 2, the vehicle cabin 14 is shown in a flat plate shape, but does not show the entire vehicle cabin 14, and a part or the whole of a member extending directly or indirectly from the vehicle cabin 14. It shows.

  More specifically, the inner shaft member 16 is formed in a cylindrical shape extending linearly in the up-down direction, and has a center hole 21 penetrating the center axis in the up-down direction. In the present embodiment, the inner shaft member 16 is formed of a metal, but may be formed of, for example, a hard synthetic resin. An upper elastic body 18 is mounted above the inner shaft member 16.

  The upper elastic body 18 is a substantially thick cylindrical rubber elastic body made of a single rubber material, and has an inner hole 22 that penetrates in a vertical direction at a central portion. The inner diameter of the inner hole 22 is substantially constant in the vertical direction, and is slightly larger than the outer diameter of the inner shaft member 16. The inner peripheral surface of the inner hole 22 is provided with an abutting protrusion 24 protruding inwardly in a part of the vertical direction, specifically, in a lower portion of the inner hole 22. At the position where the contact protrusion 24 is formed, the inner diameter of the inner hole 22 is reduced. The inner diameter of the inner hole 22 at the position where the contact protrusion 24 is formed is substantially equal to or slightly smaller than the outer diameter of the inner shaft member 16 before being assembled to the inner shaft member 16. When the body 18 is mounted on the inner shaft member 16, the contact protrusion 24 comes into contact with the outer peripheral surface of the inner shaft member 16 with zero touch or is slightly compressed. In the present embodiment, the contact protrusion 24 is provided in an annular shape over the entire circumference in the circumferential direction.

  On the other hand, the outer diameter of the upper elastic body 18 is different in the vertical direction, and the outer diameter of the lower part is made larger than the outer diameter of the upper part. The side portions are connected by a smooth curved surface. Before the upper elastic body 18 is assembled to the vehicle frame 12, the outer diameter of the lower portion of the upper elastic body 18 is substantially equal to or slightly smaller than the inner diameter of a mounting recess 48 of the vehicle frame 12 described later. When the upper elastic body 18 is assembled to the vehicle frame 12, the outer peripheral surface of the lower portion of the upper elastic body 18 comes into contact with the inner peripheral surface of the mounting recess 48 with zero touch or in the radial direction. It is designed to be compressed.

  In the center of the lower end surface of the upper elastic body 18, a circular concave portion 26 that opens downward is provided, and communicates with the inner hole 22 at the center of the circular concave portion 26. The inner diameter of the circular concave portion 26 is larger than the inner diameter of the inner hole 22, and the inner diameter of the upper elastic body 18 is larger at the lower end.

  The upper end surface of the upper elastic body 18 is fixed to the upper plate 28. The upper plate 28 is a highly rigid member made of a metal or a hard synthetic resin, and has an annular plate shape having a through hole 30 at the center. The outer diameter of the upper plate 28 is slightly larger than the outer diameter of the upper portion of the upper elastic body 18, while the inner diameter is substantially equal to or slightly smaller than the inner diameter of the inner shaft member 16. ing. That is, the inner peripheral end of the upper plate 28 protrudes more inward than the upper elastic body 18. The upper end surface of the upper elastic body 18 is vulcanized and bonded to the lower end surface of the upper plate 28. In the present embodiment, the upper elastic body 18 is formed as an integral vulcanized molded product 32 having the upper plate 28. Is formed.

  On the other hand, a lower elastic body 20 is mounted below the inner shaft member 16. Like the upper elastic body 18, the lower elastic body 20 is a substantially thick cylindrical rubber elastic body made of a single rubber material. Have. The inner diameter of the inner hole 34 is substantially constant in the vertical direction, and is substantially equal to the inner diameter of the inner hole 22 in the upper elastic body 18, that is, slightly larger than the outer diameter of the inner shaft member 16. Have been. Also, on the inner peripheral surface of the inner hole 34, a contact protrusion 36 that protrudes toward the inner peripheral side is provided in a part of the vertical direction, specifically, on an upper portion of the inner hole 34. The inner diameter at the formation position of the contact protrusion 36 is substantially equal to or slightly smaller than the outer diameter of the inner shaft member 16 before being assembled to the inner shaft member 16. Is attached to the inner shaft member 16 so that the contact protrusion 36 comes into contact with the outer peripheral surface of the inner shaft member 16 with zero touch or is slightly compressed. In the present embodiment, the contact protrusion 36 is provided in an annular shape over the entire circumference in the circumferential direction.

  The outer diameter of the lower elastic body 20 is substantially constant in the vertical direction, and the outer peripheral surface is formed by a gently curved surface that protrudes outward. The lower elastic body 20 has a lower portion provided with a continuous portion 38 over the entire circumference in the circumferential direction. The outer diameter of the lower elastic member 20 is small at the position where the lower portion 38 is formed. Have been.

  Further, a circular recess 40 that opens upward is provided at the center of the upper end surface of the lower elastic body 20, and communicates with the inner hole 34 at the center of the circular recess 40. The inner diameter of the circular recess 40 is larger than the inner diameter of the inner hole 34, and the inner diameter of the lower elastic body 20 is made larger at the upper end. In the present embodiment, the inner diameter of the circular recess 40 is made larger than the inner diameter of the circular recess 26 provided at the lower end of the upper elastic body 18.

  The lower end surface of the lower elastic body 20 is fixed to the lower plate 42. The lower plate 42 is made of the same material and shape as the upper plate 28, and has an annular plate shape having a through hole 44 at the center. The outer diameter of the lower plate 42 is substantially equal to or slightly smaller than the outer diameter of the lower elastic body 20, while the inner diameter is substantially equal to or slightly smaller than the inner diameter of the inner shaft member 16. I have. That is, the inner peripheral end of the lower plate 42 protrudes more inward than the lower elastic body 20. Then, the lower end surface of the lower elastic body 20 is vulcanized and bonded to the upper end surface of the lower plate 42. In the present embodiment, the lower elastic body 20 is formed as an integral vulcanized molded product 46 having the lower plate 42. Is formed. Particularly, in the present embodiment, the outer peripheral portion of the lower end of the lower elastic body 20 extends downward and is fixed so as to cover the outer peripheral surface of the lower plate 42.

  The integrally vulcanized molded product 32 of the inner shaft member 16 and the upper elastic body 18 and the integrally vulcanized molded product 46 of the lower elastic body 20 having the above-described structure are assembled with each other to form the vehicle cabin 14 and the vehicle frame 12. It is arranged between. Although the structure of the vehicle frame is not limited at all, in the present embodiment, it is a ladder frame and extends in a direction perpendicular to the axis (the front-rear direction or the left-right direction of the vehicle). In the vehicle frame 12 of the present embodiment, a mounting recess 48 that is recessed downward and opens upward is formed. At the center of the mounting recess 48, a mounting hole 50 that penetrates vertically is provided. ing. That is, the mounting concave portion 48 includes a cylindrical peripheral wall portion 52 extending substantially vertically and a circular bottom wall portion 54 closing a lower opening of the peripheral wall portion 52. A circular mounting hole 50 is provided. In particular, in the present embodiment, a tubular portion 56 extending in the vertical direction is formed at the opening peripheral portion of the mounting hole 50 (the inner peripheral edge portion of the bottom wall portion 54), and the outer diameter of the tubular portion 56 is formed. The dimensions are substantially equal to or slightly larger than the inner diameter of the circular recess 40 formed at the upper end of the lower elastic body 20 before assembly.

  The inner shaft member 16 is inserted into the mounting hole 50 of the vehicle frame 12, and the integrally vulcanized molded product 32 of the upper elastic body 18 is fitted into the mounting recess 48. Here, the outer diameter of the lower portion of the upper elastic body 18 before assembly is substantially equal to or slightly larger than the inner diameter of the mounting recess 48 (peripheral wall 52). The outer peripheral surface of the lower portion contacts the inner peripheral surface of the mounting concave portion 48 (peripheral wall portion 52) with zero touch or is fitted while being slightly compressed. Thus, the integrally vulcanized molded product 32 of the upper elastic body 18 is positioned and fitted in the mounting recess 48 of the vehicle frame 12 in the direction perpendicular to the axis.

  The upper portion of the inner shaft member 16 is inserted into the inner hole 22 of the upper elastic body 18, and is fixed to the inner elastic member 18 by means such as adhesion as necessary. Here, the inner diameter of the contact protrusion 24 projecting from the inner peripheral surface of the inner hole 22 of the upper elastic body 18 to the inner peripheral side is substantially equal to or slightly smaller than the outer diameter of the inner shaft member 16. Therefore, the inner peripheral surface of the contact protruding portion 24 comes into contact with the outer peripheral surface of the inner shaft member 16 with zero touch or is slightly compressed. As a result, the dimensional error of the inner shaft member 16 and the like is absorbed, and the insertion resistance of the inner shaft member 16 into the upper elastic body 18 is prevented from increasing. In addition, the inner shaft member 16 is prevented from unintentionally falling off from the upper elastic body 18.

  Further, the integrally vulcanized molded product 46 of the lower elastic body 20 is assembled to the lower portion of the inner shaft member 16 inserted into the mounting hole 50 of the vehicle frame 12 as described above. That is, the lower portion of the inner shaft member 16 is inserted into the inner hole 34 of the lower elastic body 20, and is fixed by means such as adhesion as necessary. Here, the outer diameter of the cylindrical portion 56 projecting downward in the mounting hole 50 of the vehicle frame 12 is substantially equal to or slightly larger than the inner diameter of the circular recess 40 of the lower elastic body 20 before assembly. Therefore, the cylindrical portion 56 is fitted into the circular concave portion 40 while the outer peripheral surface of the cylindrical portion 56 is in contact with the inner peripheral surface of the circular concave portion 40 with zero touch or the inner peripheral surface of the circular concave portion 40 is expanded toward the outer peripheral side. It is supposed to be. Thus, the integrally vulcanized molded product 46 of the lower elastic body 20 is positioned and fitted to the cylindrical portion 56 of the vehicle frame 12 in the direction perpendicular to the axis.

  Furthermore, the inner diameter of the contact protrusion 36 projecting from the inner peripheral surface of the inner hole 34 of the lower elastic body 20 to the inner peripheral side is substantially equal to or slightly smaller than the outer diameter of the inner shaft member 16. For this reason, the inner peripheral surface of the contact protrusion 36 comes into contact with the outer peripheral surface of the inner shaft member 16 with zero touch or is slightly compressed. As a result, the dimensional error of the inner shaft member 16 and the like is absorbed, and the insertion resistance of the inner shaft member 16 into the lower elastic body 20 is prevented from increasing. Also, the inner shaft member 16 is prevented from unintentionally falling off from the lower elastic body 20.

  That is, the inner shaft member 16 is inserted into the vehicle frame 12, and the inner shaft member 16 protrudes from the vehicle frame 12 on both sides in the up-down direction. The integrally vulcanized molded product 32 of the upper elastic body 18 and the integrally vulcanized molded product 46 of the lower elastic body 20 are assembled. In other words, the integrally vulcanized molded product 32 of the upper elastic body 18 and the integrally vulcanized molded product 46 of the lower elastic body 20 are externally fitted to the inner shaft member 16 on both sides of the vehicle frame 12 in the vertical direction. I have. In such a state, the cylindrical portion 56 of the vehicle frame 12 is located at a substantially central portion in the axial direction (vertical direction) of the inner shaft member 16, and is formed in a direction perpendicular to the axis (diameter Direction).

  The vehicle cabin 14 is superimposed on the upper end surface of the upper plate 28 in the integrally vulcanized molded product 32 of the upper elastic body 18 and bolts are attached to the vehicle cabin 14, the upper plate 28, the inner shaft member 16, and the lower plate 42. The nut 58 is inserted and the nut 60 is fastened. Thereby, the upper end portion of the inner shaft member 16 is brought into contact with the inner peripheral portion of the upper plate 28 projecting inward from the upper elastic body 18, and the lower end portion of the inner shaft member 16 is From the inner peripheral side of the lower plate 42 projecting toward the inner peripheral side. As a result, the vertical distance between the upper plate 28 and the lower plate 42 is defined by the inner shaft member 16, and the vehicle cabin 14, the upper plate 28, the lower plate 42, and the inner shaft member 16 are fixedly assembled. ing.

  The upper elastic body 18 and / or the lower elastic body 20 may be vertically moved between the upper plate 28 and the vehicle frame 12 and / or between the vehicle frame 12 and the lower plate 42 as needed. It is compressed in the direction. That is, the upper plate 28 and the lower plate 42 provided on both axial sides of the inner shaft member 16 support the vehicle frame 12 via the upper elastic body 18 and the lower elastic body 20 to support the vehicle cabin 14. And the vehicle frame 12 are elastically connected (anti-vibration connection). The contact portion between the upper end portion of the inner shaft member 16 and the inner peripheral portion of the upper plate 28 and / or the contact portion between the lower end portion of the inner shaft member 16 and the inner peripheral portion of the lower plate 42 may be provided as necessary. Then, they may be fixed by welding, bonding, or the like.

  Here, a vertically extending cylindrical member separate from the upper elastic body 18 and the lower elastic body 20 is provided between surfaces of the cylindrical portion 56 of the vehicle frame 12 and the inner shaft member 16 in the direction perpendicular to the axis. Alternatively, an annular intermediate elastic body 62 is provided. In other words, on the inner peripheral side of the cylindrical portion 56 of the vehicle frame 12, the intermediate elastic body 62 is mounted on the outer peripheral surface at the axially intermediate portion of the inner shaft member 16. The intermediate elastic body 62 is made of a foamed elastic body, and in this embodiment, is urethane foam.

  Further, in the present embodiment, the inner and outer peripheral surfaces of the intermediate elastic body 62 are both flat annular surfaces, and the outer diameter of the intermediate elastic body 62 is substantially equal to the inner diameter of the cylindrical portion 56 of the vehicle frame 12. In addition, the inner diameter of the intermediate elastic body 62 is substantially equal to or slightly smaller than the outer diameter of the inner shaft member 16. As a result, the intermediate elastic body 62 is held between the cylindrical portion 56 and the inner shaft member 16 in the radial direction, and the outer peripheral surface of the intermediate elastic body 62 substantially zero-touches the inner peripheral surface of the cylindrical portion 56. At the same time, the outer peripheral surface of the inner shaft member 16 is inserted into the inner peripheral surface of the intermediate elastic body 62 in a zero-touch state or a press-fit state in which the outer peripheral surface is slightly pushed outwardly. As a result, the intermediate elastic body 62 is temporarily fixed by being externally fitted to the inner shaft member 16.

  Furthermore, in the present embodiment, the axial dimension of the intermediate elastic body 62 is made larger than the axial dimension of the tubular portion 56 of the vehicle frame 12. Particularly, in the present embodiment, the lower surface of the intermediate elastic body 62 is located at a position substantially equal to the lower surface of the cylindrical portion 56 in the axial direction, while the upper surface of the intermediate elastic body 62 is the upper surface of the cylindrical portion 56, that is, the bottom wall portion 54. Is located above the upper surface of. In short, in the present embodiment, the intermediate elastic body 62 which is a foamed elastic body extends over the entire radially opposed surface of the vehicle frame 12 and the cylindrical portion 56, in other words, over the entire axial length of the cylindrical portion 56. Is assembled. That is, the axial dimension of the intermediate elastic body 62 is larger than the depth dimension of the two circular concave portions 26 and 40, and the upper and lower ends of the intermediate elastic body 62 are fitted into the upper and lower circular concave portions 26 and 40. At the same time, the upper and lower end surfaces of the intermediate elastic body 62 are in contact with the upper bottom surface of the circular concave portion 26 of the upper elastic body 18 and the bottom surface of the circular concave portion 40 of the lower elastic body 20, so that the intermediate elastic body 62 It is sandwiched between the elastic members 18 and 20 in the vertical direction. The intermediate elastic body 62 is preferably compressed in the vertical direction by the upper and lower elastic bodies 18 and 20. However, the intermediate elastic body 62 is not compressed. , 40 may be brought into contact with zero touch.

  In the present embodiment, the inner diameter of the circular recess 26 in the upper elastic body 18 is substantially equal to the outer diameter of the intermediate elastic body 62, and the inner peripheral surface of the circular concave 26 and the outer peripheral surface of the intermediate elastic body 62 are formed. Are brought into contact with each other with zero touch, or the upper elastic body 18 and / or the intermediate elastic body 62 are radially compressed. However, a gap may be provided between the inner peripheral surface of the circular concave portion 26 and the outer peripheral surface of the intermediate elastic body 62 in the radial direction, and the gap may be provided over the entire circumference, or may be provided on the periphery. May be partially provided, and may be appropriately set according to required spring characteristics and the like.

  The cab mount 10 of the present embodiment is, for example, in a state where it is separated into an assembled product 66 shown in FIG. It is desirable to be provided in. That is, the assembled product 66 is configured by assembling the integrally vulcanized molded product 32 of the inner shaft member 16 and the upper elastic body 18 and the intermediate elastic body 62. The inner shaft member 16 is inserted and temporarily fixed to the elastic body 62, and the integrally vulcanized molded product 32 of the upper elastic body 18 is mounted on the upper part of the inner shaft member 16. When the vehicle is mounted on a vehicle, the inner shaft member 16 is inserted into the mounting hole 50 of the vehicle frame 12 from above, and the lower outer peripheral portion of the upper elastic body 18 of the assembly 66 is mounted in the mounting recess 48 of the vehicle frame 12. Are fitted, and the integrally vulcanized molded product 46 of the lower elastic body 20 is externally mounted on the lower portion of the inner shaft member 16 protruding downward from the mounting hole 50. Further, the vehicle cabin 14 is superimposed on the upper plate 28 and the lower plate 42, and the vehicle cabin 14 is fastened to the inner shaft member 16 with the bolts 58 and the nuts 60. It is interposed between the frame 12 and the vehicle cabin 14. In the assembled product 66, the integrally vulcanized molded product 32 of the upper elastic body 18 and the inner shaft member 16 may be, for example, such that the contact protrusion 24 of the upper elastic body 18 abuts on the outer peripheral surface of the inner shaft member 16. The contact portion between the upper plate 28 and the inner shaft member 16 may be prevented from falling off by welding each other or using an appropriate jig.

  In the cab mount 10 having the above-described structure, the load in the direction in which the vehicle cabin 14 and the vehicle frame 12 approach (bound direction in which the vehicle cabin 14 relatively moves downward) is input, so that the upper elastic body 18 is It is compressed and deformed, and exhibits an anti-vibration effect. Further, when a load is input in a direction in which the vehicle cabin 14 and the vehicle frame 12 are separated from each other (a rebound direction in which the vehicle cabin 14 relatively moves upward), the lower elastic body 20 is compressed and deformed, thereby exhibiting a vibration damping effect. Is done. On the other hand, when vibration including a component perpendicular to the axis in the front-rear direction or the left-right direction of the vehicle is input, an intermediate elastic body (foam elastic) is formed between the cylindrical portion 56 of the vehicle frame 12 and the inner shaft member 16 in the radial direction. By compressing the body 62, an anti-vibration effect is exhibited.

  Here, when assembling the cab mount 10 between the vehicle frame 12 and the vehicle cabin 14, the inner shaft member 16 moves with respect to the vehicle frame 12 due to a dimensional tolerance or an assembly error of each member. And may deviate from the design reference position in the front-rear direction or the left-right direction. On the other hand, in the present embodiment, since the foamed elastic body (intermediate elastic body 62) is provided between the inner shaft member 16 and the cylindrical portion 56 of the vehicle frame 12 in the radial direction, the spring characteristics are greatly affected. , The tolerance and the assembly error can be absorbed. In other words, by employing the cab mount 10 of the present embodiment, the desired anti-vibration effect can be stably exhibited even in the presence of the above-described tolerance and assembly error.

  In the present embodiment, the inner shaft member 16 and the intermediate elastic body (foamed elastic body) 62 are temporarily fixed to each other by inserting the inner shaft member 16 into the intermediate elastic body (foamed elastic body) 62. With this configuration, it is possible to prevent the intermediate elastic body (foamed elastic body) 62 from unintentionally falling off from the inner shaft member 16. Thus, for example, even when a part of the cab mount 10 is shipped to the market in a state of the assembled product 66, the assembled state can be stably maintained. Further, the intermediate elastic body (foamed elastic body) 62 and the vehicle frame 12 are prevented from being bonded to each other, so that the efficiency of the assembling operation can be improved.

  Furthermore, in the present embodiment, the vertical dimension of the intermediate elastic body (foamed elastic body) 62 is made larger than the vertical dimension of the tubular portion 56, and the radially opposed surface of the vehicle frame 12 and the inner shaft member 16. An intermediate elastic body (foamed elastic body) 62 is assembled over the entirety of. Thus, a stable anti-vibration effect can be exhibited with respect to vibration in the vehicle front-rear direction and left-right direction. Also, the vertical dimension of the intermediate elastic body (foamed elastic body) 62, and thus the volume, can be sufficiently ensured.

  In addition, the present inventors have confirmed through experiments that the change in the spring characteristics due to the displacement of the inner shaft member 16 with respect to the vehicle frame 12 can be suppressed by employing the cab mount 10 according to the present invention. FIG. 4 shows the results. In FIG. 4, a black line indicates an example, and a gray line indicates a comparative example. In the comparative example, the intermediate elastic body is not a foamed elastic body but a non-foamed elastic body. Things. Further, the amount of displacement in the front-rear direction as the X axis in FIG. 4 indicates the amount of displacement of the inner shaft member 16 from the coaxial position with the mounting hole 50 as the design reference position with respect to the vehicle frame 12. As the dynamic spring constant Kd, those having the same value at the design reference position in the example and the comparative example were adopted.

  That is, as shown by a gray line in FIG. 4, when the intermediate elastic body is formed of a non-foamed elastic body, the dynamic spring constant increases as the displacement of the inner shaft member with respect to the vehicle frame increases. On the other hand, in the embodiment having the structure according to the present invention, even if the amount of displacement of the inner shaft member 16 with respect to the vehicle frame 12 increases, the degree of increase in the dynamic spring constant is suppressed. That is, in the embodiment in which the intermediate elastic body 62 is formed of the foamed elastic body, the influence on the mount spring characteristics due to the dimensional tolerance and the assembly error of the parts is reduced, and the intended vibration damping effect is stably achieved. It is possible to obtain.

  As described above, the embodiments of the present invention have been described in detail, but the present invention is not to be construed as being limited by the specific description in the embodiments.

  For example, in the above-described embodiment, the foamed elastic body (intermediate elastic body 62) is made of urethane foam. However, the material is not limited as long as it is an elastic body having bubbles inside. May be done. The form of the cells may be closed cells or open cells, but depending on the modulus of elasticity, the foaming rate, the characteristics of the elastic body constituting the skeleton portion, etc. In this case, it is possible to more effectively reduce a change in dynamic spring characteristics by suppressing the influence of the air spring.

  Further, in the above-described embodiment, the intermediate elastic body 62 is formed in a cylindrical shape extending continuously over the entire circumference in the circumferential direction. For example, it may be provided on both sides in the front-rear direction and / or both sides in the left-right direction with the inner shaft member interposed therebetween. Furthermore, even when the intermediate elastic body is cylindrical, the inner and outer peripheral surfaces of the intermediate elastic body need not be flat annular surfaces as in the above-described embodiment, but the inner peripheral surface of the intermediate elastic body. A contact protrusion may be provided on the outer peripheral surface, for example, similarly to the inner peripheral surfaces of the upper and lower elastic bodies. Alternatively, irregularities may be provided on the outer peripheral surface of the inner shaft member or the inner peripheral surface of the cylindrical portion of the vehicle frame. The inner and outer peripheral surfaces of the intermediate elastic body are provided with or without such abutting projections and irregularities, and the inner and outer peripheral surfaces of the inner shaft member and the inner peripheral surface of the vehicle frame (the inner peripheral surface of the tubular portion 56). Surface) may be separated from each other, may be in contact with zero touch, or may be pressed in a compressed state. That is, the radial thickness of the intermediate elastic body, the cylindrical portion, and the inner shaft member can be partially varied, thereby setting the non-linear characteristics as the load-displacement spring characteristics in the direction perpendicular to the axis. Is also possible.

  Further, the mode of providing the cab mount according to the present invention is not limited to the mode provided in a state where the assembled product 66 and the integrally vulcanized molded product 46 of the lower elastic body 20 shown in FIG.

  Furthermore, in the above-described embodiment, the vertical dimension of the intermediate elastic body 62 is larger than the vertical dimension of the cylindrical portion 56 of the vehicle frame 12, but the vertical dimension of the intermediate elastic body is The dimension may be smaller than the vertical dimension. The structure of the vehicle frame is not particularly limited as long as the mounting hole through which the inner shaft member is inserted is formed, and the mounting concave portion and the cylindrical portion are not essential. Further, even when the cylindrical portion is provided, it is not necessary to provide the tubular portion directly to the vehicle frame, and it may be provided to another component fixedly mounted to the vehicle frame. As shown in FIG. 1, it is also possible to form a cylindrical portion by fixedly attaching a separate part fixed or non-fixed to the upper elastic body or the lower elastic body to the vehicle frame. .

  The specific structure and shape of the integrally vulcanized molded article of the upper elastic body and the integrally vulcanized molded article of the lower elastic body are not limited at all. For example, the upper elastic body and / or the lower elastic body may be provided with a restraining or reinforcing member such as an outer ring or an inter ring for the purpose of tuning elastic characteristics or the like. It does not need to be alone. Further, in order to realize the required radial and axial spring characteristics, a hollow portion may be provided partially or a fluid chamber in which an incompressible fluid is sealed may be formed.

  Note that the inner shaft member does not need to be formed in a hollow cylindrical shape as in the above-described embodiment, and may be a solid member such as a bolt configured to fix the upper plate and the lower plate. Further, for example, the inner shaft member and the upper plate or the lower plate may be formed integrally. Furthermore, the intermediate elastic body does not need to be entirely composed of a foamed elastic body, and may adopt a composite structure of a foamed elastic body and a non-foamed elastic body in consideration of required characteristics and the like. It is. In addition, it is not necessary to provide the circular concave portion 26 or the like in the upper elastic body at the assembly portion of the intermediate elastic body, and the intermediate elastic body and the upper elastic body may be overlapped only in the axial direction.

10: Cab mount, 12: Vehicle frame, 14: Vehicle cabin, 16: Inner shaft member, 18: Upper elastic body, 20: Lower elastic body, 28: Upper plate, 42: Lower plate, 50: Mounting hole, 56: Tubular part, 62: intermediate elastic body (foamed elastic body)

Claims (4)

An upper elastic body and a lower elastic body are attached to an inner shaft member that is inserted into the mounting hole of the vehicle frame and attached to the vehicle cabin, and the upper plate and the lower plate provided on both axial sides of the inner shaft member. In a cab mount, the vehicle frame is axially sandwiched between the plates via the upper elastic body and the lower elastic body, and is vibration-coupled to the vehicle cabin.
On the outer peripheral surface of the axially intermediate portion of the inner shaft member, an intermediate elastic body positioned between opposing surfaces of the inner shaft member and the vehicle frame in a direction perpendicular to the axis is the upper elastic body and the lower elastic body. A cab mount provided as a separate member of the above, wherein the intermediate elastic body is constituted by a foamed elastic body.   The cab mount according to claim 1, wherein the intermediate elastic body is urethane foam.   The cab mount according to claim 1 or 2, wherein the intermediate elastic body is formed in an annular shape that is continuous in a circumferential direction, and is temporarily fixed by external fitting to the inner shaft member.   The vehicle frame is provided with a cylindrical portion extending in the axial direction opposite to the outer peripheral surface of the axially intermediate portion of the inner shaft member in a direction perpendicular to the axis, and the intermediate elastic body is provided in the cylindrical portion. The cab mount according to any one of claims 1 to 3, wherein the cab mount is disposed on an inner peripheral side of the cylindrical portion and is disposed over the entire length of the cylindrical portion in the axial direction.