Vibration isolator

Abstract

A vibration isolator includes: a pair of opposing members fixed to a vehicle body of the vehicle so as to be located on both sides of a protrusion projecting from an outer peripheral edge of the powertrain in a direction perpendicular to the principal axes of inertia to oppose each other in the direction around the principal axes of inertia; a pre-pressed part provided on a part of each of the opposing members facing the protrusion to be pre-pressed by the opposing member and the protrusion in the direction around the principal axes of inertia; and a contacting portion provided on a part of each of the opposing members facing the protrusion so as to be spaced apart from the protrusion and to contact the protrusion when the powertrain vibrates in the direction around the principal axes of inertia.

Description

background

[0001] A technology disclosed in the present patent specification relates to a vibration isolator, in particular a vibration isolator designed to reduce vibration of a powertrain mounted on a vehicle in a rolling direction.

[0002] Examined Japanese Utility Model Publication No. JP H03-588 Y2 discloses an example of a vibration isolator for reducing vibration of a transmission integrated with an engine. The vibration isolator includes a stopper made of a steel sheet with a U-shaped cross-section, bolted to the transmission and extending along an output shaft of the engine, and a U-shaped member made of a steel sheet provided on a vehicle body.

[0003] The stopper lug comprises a pair of side plates facing each other in a horizontal direction, and oscillates in the horizontal direction, i.e., in a direction in which the side plates face each other, when the transmission vibrates relatively strongly, for example, during engine on / off. An insulator rubber in the shape of a rectangular frame, viewed in plan view, is attached to an outer surface of each of the side plates.

[0004] The U-shaped element is arranged so that, in plan view, it surrounds the side plates of the stop nose. The side plates of the U-shaped element face the insulator rubbers, with a gap between them.

[0005] When the motor is turned on / off, the gearbox vibrates in a direction perpendicular to the motor's output shaft. At this time, the isolator rubbers contact the side plates of the U-shaped element to reduce the gearbox vibration.

[0006] A comparable vibration isolator for reducing drivetrain vibrations is known from JP 2007 - 191 063 A. JP 2009 - 298 316 A, JP 2000 - 2 298 A, and JP 2005 - 106 138 A show further vibration dampers. Summary

[0007] When a drive power (torque) of the engine fluctuates greatly, for example, when the engine is turned on / off, the entire driveline vibrates in a rolling direction (a direction around principal axes of inertia) with a relatively large amplitude due to a reaction force (torque). In order to reduce the vibration in the rolling direction with the vibration isolator, the stopper lug is provided on an outer periphery of the gearbox perpendicular to the principal axes of inertia, and the U-shaped member is fixed to the vehicle body such that the side plates of the U-shaped member are arranged on both sides of the stopper lug in the rolling direction. Thus, when the vibration in the rolling direction is generated, the isolator rubbers attached to the stopper lug contact the side plates of the U-shaped member, thereby reducing the vibration of the driveline in the rolling direction.

[0008] However, according to the vibration isolator described above, a gap is formed between the isolator rubbers and the side plates of the U-shaped member. When vibration is generated in the rolling direction, the isolator rubbers collide with the side plates of the U-shaped member, and the impact of the collision may potentially be transmitted to the vehicle body. Furthermore, the collision may generate noise.

[0009] In view of the foregoing, it is an object of the present invention to prevent transmission of the vibration of the drive train mounted on the vehicle in the rolling direction to the vehicle body.

[0010] This object is solved by the subject matter of claim 1. Preferred embodiments of the present invention are the subject matter of the subclaims.

[0011] For the purpose described above, the disclosed technology provides the drive train with a protrusion extending in a direction substantially perpendicular to the principal axes of inertia, and elastic bodies arranged on both sides of the protrusion in the rolling direction are pre-pressed.

[0012] In particular, the present technology is directed to a vibration isolator designed to reduce vibration of the vehicle-mounted powertrain in the direction around the principal axes of inertia and provides the following solution.

[0013] Specifically, the vibration isolator of the disclosed technology includes: a pair of opposing members fixed to a vehicle body of the vehicle so as to be located on both sides of a protrusion projecting from an outer peripheral edge of the powertrain in a direction perpendicular to the principal axes of inertia to oppose each other in the direction around the principal axes of inertia; a pre-pressed portion provided at a portion of each of the opposing members facing the protrusion to be pre-pressed by the opposing member and the protrusion in the direction around the principal axes of inertia; and a contacting portion provided at a portion of each of the opposing members facing the protrusion to be spaced apart from the protrusion and contacting the protrusion when the powertrain vibrates in the direction around the principal axes of inertia.

[0014] With this structure, when the powertrain vibrates in the rolling direction, the protrusion vibrates in the rolling direction. At this time, the protrusion compresses the pre-compressed part in the rolling direction because the pre-compressed part has been compressed by the protrusion and the opposing elements in the rolling direction. Thus, the protrusion smoothly rotates in the rolling direction. As the protrusion continues to rotate in the rolling direction, the protrusion contacts the contacting part. At this time, the protrusion, which rotates smoothly in the rolling direction as described above, contacts the contacting part. Thus, collision of the protrusion and the contacting part can be prevented. This can prevent transmission of the vibration of the powertrain in the rolling direction to the vehicle body and can prevent generation of collision noise.

[0015] The principal axes of inertia preferably extend in a substantially horizontal direction, a protrusion direction of the projection preferably intersects the horizontal direction, and the pre-pressed parts and the contacting parts preferably extend in a direction substantially perpendicular to the projection.

[0016] In this structure, the protrusion direction of the protrusion intersects the horizontal direction, and the pre-pressed parts and the contacting parts extend in the direction substantially perpendicular to the protrusion direction of the protrusion. Thus, when the powertrain vibrates in a vertical direction while the vehicle is being driven, for example, the protrusion also vibrates in the vertical direction. At this time, the pre-pressed parts and the contacting parts warp to deform substantially in a shear direction. Accordingly, the vibration of the powertrain in the vertical direction is not easily transmitted to the vehicle body through the elastic bodies (the pre-pressed parts) and the opposing members. This can improve a property of the vibration isolator of preventing the transmission of vibration in the vertical direction.

[0017] Parts of the projection facing the opposing elements are preferably flat along the projection direction of the projection, and the pre-pressed parts preferably extend to be closer to the projection than the contacting parts.

[0018] In this design, the parts of the protrusion facing the opposing elements are flat. Thus, the shape of the protrusion is relatively simple. Even though changing the shape of the vehicle's drivetrain is relatively difficult, the relatively simple shape of the protrusion makes it possible to easily change the shape of the drivetrain.

[0019] Preferably, a gap is formed between the pre-pressed part and the contacting part provided on the same opposing element.

[0020] With this structure, the pre-pressed parts and the contacting parts are prone to warping in the shear direction because the gap between the pre-pressed part and the contacting part is provided on the same opposing member. Thus, when the powertrain vibrates in the vertical direction, the pre-pressed parts and the contacting parts are prone to warping in the shear direction, and the spring constant of the vibration isolator can be reduced in the vertical direction. This can further improve the vibration transmission prevention property of the vibration isolator.

[0021] An end of one of the opposing members and an end of the other opposing member on a side in a direction of the principal inertia axes are preferably coupled by a coupling member, and a projection for positioning the projection in the direction of the principal inertia axes is preferably formed on a part of the coupling member facing the projection.

[0022] With this design, the vibration isolator is brought closer to the vehicle body from one side of the protrusion in the direction of the principal axes of inertia when mounting the vibration isolator on the vehicle body. At this time, the positioning projection contacts the protrusion to determine the position of the vibration isolator in the direction of the principal axes of inertia. This facilitates the installation of the vibration isolator.

[0023] The disclosed technology can prevent the transmission of driveline vibration in the rolling direction to the vehicle body. Brief description of the drawings Fig. 1 is a side view showing a vehicle equipped with a vibration isolator of an exemplary embodiment. Fig. 2A is a schematic view viewed from a front of the vehicle, showing a transmission to which the vibration isolator of the exemplary embodiment is attached. Fig. Figure 2B is an enlarged view showing part A of Fig. 2A shows. Fig. 3 is a perspective view of part A of Fig. 2A seen from the front of the vehicle. Fig. 4 is a perspective view showing part A of Fig. 2A as seen from a rear side of the vehicle. Fig. 5 is a perspective view showing the vibration isolator. Fig. Figure 6A is a plan view showing the vibration isolator. Fig. Figure 6B is a bottom view showing the vibration isolator. Fig. Figure 6C is a front view showing the vibration isolator. Fig. Figure 6D is a side view showing the vibration isolator. Fig. 7 is a sectional view along the line VII-VII of Fig. 6A. Fig. 8A is a view corresponding to a cross-sectional view taken along the line VIII-VIII of Fig. 6D, which shows a vibration isolator of a first alternative of the exemplary embodiment. Fig. 8B is a view corresponding to the cross-sectional view taken along the line VIII-VIII of Fig. 6D, which shows a vibration isolator of a second alternative of the exemplary embodiment. Fig. 8C is a view corresponding to the cross-sectional view along the line VIII-VIII of Fig. 6D, which shows a vibration isolator of a third alternative of the exemplary embodiment. Fig. 8D is a view corresponding to the cross-sectional view along the line VIII-VIII of Fig. 6D, which shows a vibration isolator of a fourth alternative of the exemplary embodiment. Fig. 8E is a view corresponding to the cross-sectional view along the line VIII-VIII of Fig. 6D, which shows the vibration isolator of the fourth alternative of the exemplary embodiment. Fig. 9D is a view corresponding to the cross-sectional view along the line VIII-VIII of Fig. 6D, which shows a vibration isolator of a fifth alternative of the exemplary embodiment. Fig. 9B is a view corresponding to the cross-sectional view taken along the line VIII-VIII of Fig. 6D, which shows a vibration isolator of a sixth alternative of the exemplary embodiment. Fig. 10A is a view corresponding to the cross-sectional view taken along the line XX of Fig. 6D, which shows a vibration isolator of a seventh alternative of the exemplary embodiment. Fig. 10B is a view corresponding to the cross-sectional view taken along the line XX of Fig. 6D, which shows a vibration isolator of an eighth alternative of the exemplary embodiment. Fig. 10C is a view corresponding Fig. 6D, which shows a vibration isolator of a ninth alternative of the exemplary embodiment. Fig. 11A is a perspective view showing a stopper rubber of a vibration isolator of a tenth alternative of the exemplary embodiment. Fig. 11B is a front view showing the stopper rubber of the vibration isolator of the tenth alternative of the exemplary embodiment. Fig. 11C is a front view showing the stopper rubber of the vibration isolator of the tenth alternative of the exemplary embodiment. Fig. 12A is a perspective view showing a vibration isolator of an eleventh alternative of the exemplary embodiment. Fig. 12B is a perspective view showing the vibration isolator of the eleventh alternative of the exemplary embodiment. Fig. 13A is a plan view showing the vibration isolator of the eleventh alternative of the exemplary embodiment. Fig. 13B is a side view showing the vibration isolator of the eleventh alternative of the exemplary embodiment. Detailed description

[0024] An exemplary embodiment will be described with reference to the drawings.

[0025] A vibration isolator 1 of the exemplary embodiment is a vibration isolator mounted on a general vehicle 3.

[0026] Fig. 1 is a side view showing the vehicle 3. A lower cross panel 9, which separates an engine compartment 5 and a passenger compartment 7 in a longitudinal direction of the vehicle 3, is provided in a front part of the vehicle 3. A floor panel 11 is connected to a lower end of the lower cross panel 9 to extend rearward in a substantially horizontal direction.

[0027] In the engine compartment 5 is a drive train 23, which includes an engine, a transmission 21 (see Fig. 2A), etc. The powertrain 23 is supported by a pair of front side frames 25, 26 extending in the longitudinal direction of the vehicle on both sides of the engine compartment 5 in a width direction of the vehicle.

[0028] Fig. 1 shows an outline of the vehicle 3 and components schematically by virtual lines, except for the powertrain 23 and the front side frame 26.

[0029] Fig. 2A is a schematic view showing the powertrain 23 as viewed from a front of the vehicle. Fig. Fig. 2A schematically shows an outline of the transmission 21. When a drive power of the engine fluctuates greatly, e.g., when the engine is switched on / off, the drive train 23 oscillates due to a reaction force with a relatively large amplitude in a direction around principal axes of inertia X, ie, in a rolling direction (in the directions of the Fig. 2A). The drive train 23 is provided with the vibration isolator 1, which is designed to reduce the vibration in the rolling direction.

[0030] A vehicle body of the vehicle 3 includes a pair of side frames 25, 26 made of steel sheets, arranged on both sides of the vehicle in the width direction of the vehicle so as to face each other, and extending in the longitudinal direction of the vehicle. The powertrain 23 has the principal axes of inertia X extending in a horizontal direction and is mounted on the side frames 25, 26 by a vibration isolator (not shown).

[0031] A protruding nose (a projection) 27 is integrally formed on an outer peripheral edge of the transmission 21 of the power train 23 to extend in a direction perpendicular to the horizontal direction, that is, in a direction perpendicular to the principal axes of inertia X of the power train 23. Specifically, the protruding nose 27 extends obliquely downward to meet one of the side frames (the left side frame 25 in Fig. 2A). Fig. Figure 2B is an enlarged view showing part A of Fig. 2A shows. The protruding nose 27 is formed from a substantially rectangular parallelepiped metal block, and end surfaces 27a, 27a thereof (parts of the projection facing the opposing elements) facing in the rolling direction are flat along the projecting direction of the protruding nose 27. Each of the end surfaces 27a, 27a has a pair of linear protrusions 27b, 27b formed at the center of the end surface 27a in the projecting direction so as to be spaced from each other in the projecting direction and extend along the principal axes of inertia X. A bracket 29, to which the vibration isolator 1 is bolted, is provided on a part of the side frame 25 in the longitudinal direction of the vehicle in front of the protruding nose 27 (see Fig. 2A).

[0032] Fig. 3 and Fig. 4 show part A of Fig. 2A seen from the front and back. Fig. 5 is a perspective view showing the vibration isolator 1. Fig. 6A is a plan view showing the vibration isolator 1, Fig. 6B is a bottom view showing the vibration isolator 1, Fig. 6C is a front view showing the vibration isolator 1, and Fig. 6D is a left side view showing the vibration isolator 1. Fig. 7 is a cross-sectional view along the line VII-VII of Fig. 6A. A rear view and a right side view of the vibration isolator 1 are not shown since they are substantially the same as the front view and the left side view.

[0033] The vibration isolator 1 comprises a bracket 31 having a U-shaped cross section which is fixed to the side frame 25, and stopper rubbers 35, 35 which are arranged on inner surfaces of a pair of opposing parts (opposing elements) 33, 33 of the bracket 31.

[0034] The holder 31 is formed by bending a rectangular steel sheet into the U-shape and has the opposing parts 33, 33 in the shape of a rectangular sheet opposite each other, and a coupling part 37 (a coupling member) in the shape of a rectangular sheet couples one end of one of the opposing parts 33 and one end of the other opposing part 33 at one side in the longitudinal direction of the opposing parts 33, 33.

[0035] A projection 39 of a substantially conical elastic body is formed in the center of a surface of the coupling part 37 facing the opposing parts 33, as shown in Fig. 4, etc. Bolt holes 41, 41, .... for receiving bolts (not shown) for fastening the holder 31 to the side frame 25 are formed in the coupling part 37 between four corners of the coupling part 37 and the projection 39, closer to the projection 39 than to the four corners. Weld nuts 43 are provided on the surface of the coupling part 37 facing the opposing parts 33 to correspond to the bolt holes 41.

[0036] A transition between each of the opposing parts 33 and the coupling part 37 is curved, and each of the opposing parts 33 is inclined outward by 1.5 degrees relative to a direction perpendicular to the coupling part 37. The opposing parts 33, 33 are fixed to the side frame 25 by the coupling part 37.

[0037] Each of the stopper rubbers 35 includes three ribs 35a, 35b, 35b arranged in a width direction of the opposing parts 33. Each of the ribs 35a, 35b, 35b extends linearly in a longitudinal direction of the opposing parts 33. A first rib 35a in the middle of the three ribs 35a, 35b, 35b (a pre-pressed part) has a dimension larger than that of the second ribs 35b, 35b (contacting parts) on both sides of the first rib 35a in a protruding direction thereof. The first rib 35a has a trapezoidal cross-section, and surfaces facing the second ribs 35b are inclined such that a width of the first rib 35a increases with a decreasing distance from a bottom of the first rib 35a.Each of the second ribs 35b has a substantially rectangular cross-section, and a surface facing the first rib 35a is inclined such that a width of the second rib 35b increases with a decreasing distance from a bottom of the second rib 35b. A surface of the second rib 35b opposite the surface facing the first rib 35a extends along the direction in which the opposing parts 33, 33 face each other. Linear grooves 35c, 35c (gap) extending in the longitudinal direction of the opposing parts 33 are formed between each of the second ribs 35b, 35b and the first rib 35a. Each of the linear grooves 35c tapers toward its bottom.

[0038] The vibration isolator 1 configured as described above is fixed to the vehicle body of the vehicle 3 by bolting the coupling part 37 to the bracket 29 of the side frame 25, with an opening of the U-shaped bracket 31 facing the longitudinal direction of the vehicle, and the pair of opposing parts 33, 33 opposing the protruding lug 27 of the transmission 21. In the attached state, each of the opposing parts 33 is arranged parallel to the end surfaces 27a of the protruding lug 27 facing the opposing parts 33.

[0039] In this state, the first rib 35a of the stopper rubber 35 provided on each of the opposing parts 33 extends in a direction perpendicular to the protruding direction of the protruding projection 27 and is pressed into contact with the end surface 27a. In other words, the first rib 35a is pre-pressed in the rolling direction by the protruding projection 27 and the opposing part 33. The ridges 27b, 27b formed on the end surface 27a of the protruding projection 27 are located on both sides of a tip of the first rib 35a in the width direction. This can prevent misalignment of the first rib 35a in the width direction.

[0040] When the bolts are fastened, each of the second ribs 35b of the stopper rubber 35 provided on the opposing part 33 is spaced from the projecting nose 27 to form a gap S between the second rib 35b and the end surface 27a facing the second rib 35b.

[0041] The projection 39 formed on the coupling part 37 of the bracket 31 contacts a front end surface 27c of the projecting nose 27. Thus, the vibration isolator 1 is positioned in the longitudinal direction of the vehicle.

[0042] The following describes the behavior of the vibration isolator 1 in response to an engine start / stop operation. When the engine is turned on or off, the engine's drive power fluctuates greatly, and the drive train 23 vibrates in the rolling direction due to a reaction force with a relatively large amplitude.

[0043] In an early phase of vibration, the protruding lug 27, which is part of the drive train 23, rotates in the rolling direction. However, since the first rib 35a of the stop rubber 35, which is located on one side of the protruding lug 27 in the rolling direction, is pre-compressed, the protruding lug 27 compresses the first rib 35a. As a result, the protruding lug 27 rotates smoothly in the rolling direction.

[0044] When the protruding nose 27 continues to rotate toward one side in the rolling direction, the protruding nose 27 contacts the second ribs 35b, 35b of the stopper rubber 35 located on one side of the protruding nose 27 in the rolling direction. At this time, the protruding nose 27, which smoothly rotates in the rolling direction as described above, smoothly contacts the second ribs 35b, 35b.

[0045] Thus, the vibration isolator 1 can prevent the protruding nose 27 from rotating excessively in the rolling direction and can prevent the protruding nose 27 from colliding with the second ribs 35b, 35b. This can prevent the relatively large vibration of the powertrain 23 in the rolling direction from being transmitted to the vehicle body of the vehicle 3 and can prevent the generation of collision noise.

[0046] A protrusion direction of the protruding projection 27 intersects the horizontal direction. The first rib 35a and the second ribs 35b, 35b of the stopper rubber 35 above the protruding projection 27 and the first rib 35a and the second ribs 35b, 35b of the stopper rubber 35 below the protruding projection 37 extend in a direction perpendicular to the protruding projection 27. Specifically, the first ribs 35a, 35a and the second ribs 35b, 35b, 35b, 35b extend in a direction intersecting the vertical direction. For example, the protruding projection 27 swings in the vertical direction when the driveline 23 swings in the vertical direction while the vehicle 3 is driven. At this time, the first ribs 35a and the second ribs 35b, 35b, 35b, 35b warp to deform substantially in the shear direction.Thus, the vibration of the drive train 23 in the vertical direction is not easily transmitted to the vehicle body through the stopper rubbers 35, 35 and the bracket 31. This can improve a property of the vibration isolator 1 of preventing the transmission of vibration in the vertical direction. -Advantages of the exemplary embodiment-

[0047] The above-described embodiment can prevent the protruding nose 27 from colliding with the second ribs 35b, 35b. This can prevent the vibration of the drive train 23 in the rolling direction from being transmitted to the vehicle body of the vehicle 3 and can prevent the generation of collision noise.

[0048] As described above, the above-described embodiment can improve the property of the vibration isolator 1 of preventing the transmission of vibration in the vertical direction.

[0049] According to the above-described embodiment, the end surfaces 27a, 27a of the protruding nose 27 facing the opposing parts 33, 33 are flat, and therefore the shape of the protruding nose 27 is relatively simple. Although changing the shape of the drive train 23 of the vehicle 3 is relatively difficult, the relatively simple shape of the protruding nose 27 makes it possible to easily change the shape of the drive train 23.

[0050] According to the above-described embodiment, the grooves 35c, 35c are formed as gaps between the first rib 35a and each of the second ribs 35b, 35b, and the first and second ribs 35a, 35b, 35b are easily distorted in the shear direction. Thus, when the powertrain 23 vibrates in the vertical direction, the first rib 35a and the second ribs 35b, 35b are easily distorted in the shear direction. Thus, a spring constant of the vibration isolator 1 in the vertical direction can be reduced.

[0051] According to the above-described embodiment, when mounting the vibration isolator 1 to the side frame 25, the vibration isolator 1 is brought closer to the side frame 25 from the rear side of the protruding lug 27. At this time, the projection 39 contacts the protruding lug 27 to determine the position of the vibration isolator 1 in the longitudinal direction. This facilitates the mounting of the vibration isolator 1.

[0052] The above-described embodiment can effectively reduce the vibration of the transmission 21 of the vehicle 3 in the rolling direction.

[0053] According to the above-described embodiment, the shape of the holder 31 can be changed as needed. Thus, the volume of the stop rubbers 35 is not limited. (First alternative)

[0054] Fig. 8A is a view corresponding to the cross-sectional view taken along the line VIII-VIII of Fig. 6D, which shows a vibration isolator 1a of a first alternative of the above-described embodiment. The vibration isolator 1a has stopper rubbers 45 of a shape different from the stopper rubbers 35 of the vibration isolator 1 of the above-described embodiment. Specifically, each of the stopper rubbers 45 includes a second rib 45b formed at the center in its width direction, and first ribs 45a, 45a formed on both sides of the second rib 45b in the width direction and having a dimension larger than that of the second rib 45b in a protrusion direction thereof.

[0055] In this structure, the first ribs 45a, 45a on both sides of the second rib 45b are pre-pressed by the protruding lug 27 and the opposing portion 33. The second rib 45b is spaced from the protruding lug 27 and contacts the protruding lug 27 when the driveline 23 oscillates in the rolling direction. (Second alternative)

[0056] Fig. 8B is a view corresponding to the cross-sectional view taken along the line VIII-VIII of Fig. 6D, which shows a vibration isolator 1b of a second alternative of the exemplary embodiment. The vibration isolator 1b has stopper rubbers 55 of a shape that differs from the shape of the stopper rubbers 35 of the vibration isolator 1 of the previously described embodiment. Specifically, a first rib 55a is tapered to have a triangular cross-section.

[0057] With this structure, when the drive train 23 vibrates in the rolling direction, an elastic repulsion force exerted on the protruding lug 27 gradually increases, and the rotation of the drive train 23 in the rolling direction gradually slows down. The elastic repulsion force exerted on the protruding lug 27 by the first rib 55a at an early stage of the vibration of the drive train 23 is smaller than the elastic repulsion force exerted by the first rib 35a of the first embodiment and gradually increases. Thus, the protruding lug 27 contacts the second ribs 55b, 55b more smoothly. This can further improve a property of the bump stop rubbers. (Third alternative)

[0058] Fig. 8C is a view corresponding to the cross-sectional view along the line VIII-VIII of Fig. 6D, which shows a vibration isolator 1c of a third alternative of the above-described embodiment. The vibration isolator 1c has stopper rubbers 65 of a shape different from the shape of the stopper rubbers 35 of the vibration isolator 1 of the above-described embodiment. Specifically, the vibration isolator 1c differs from the vibration isolator 1 in that a first rib 65a and second ribs 65b of each of the stopper rubbers 65 are designed smaller than the first rib 35a and second ribs 35b of the vibration isolator 1 in its width direction, and a pair of second ribs 65b are formed on each side of the first rib 65a in the width direction.

[0059] With this structure, the first rib 65a and the second ribs 65b are more easily deformed in the shear direction than the first rib 35a and the second ribs 35b, and a spring constant of the vibration isolator 1c in the vertical direction is reduced compared with the spring constant of the vibration isolator 1. (Fourth alternative)

[0060] Fig. 8D and Fig. 8E are views corresponding to the cross-sectional view along the line VIII-VIII of Fig. 6D, showing a vibration isolator 1d of a fourth alternative of the above-described embodiment. The vibration isolator 1d has stopper rubbers 75 of a shape different from the shape of the stopper rubbers 35 of the vibration isolator 1 of the above-described embodiment. Specifically, the vibration isolator 1d differs from the vibration isolator 1 in that a front end surface of the first rib 75a is provided with projections and recesses. By providing the projections and recesses in the front end surface of the first rib 75a, a cushioning property is imparted to the front end surface.

[0061] As the first rib 75a wears over time and its pre-pressing effect is reduced, noise is easily generated at the first rib 75a contacting the protruding lug 27. With the above-described structure, the front end surface of the first rib 75a has a cushioning effect and can easily reduce noise. (Fifth alternative)

[0062] Fig. 9A is a view corresponding to the cross-sectional view taken along the line VIII-VIII of Fig. 6D, which shows a vibration isolator 1e of a fifth alternative of the above-described embodiment. The vibration isolator 1e differs from the vibration isolator 1 in that the stopper rubbers 85 are integrally formed on a metal sheet 87. Specifically, a first rib 85a of each of the stopper rubbers 85 is integrally formed on the rectangular metal sheet 87, which is arranged in a central portion of the first rib 85a.

[0063] With this structure, a spring constant of the first rib 85a in the protrusion direction can be increased while reducing an increase in the spring constant of the first rib 85a in the shearing direction as much as possible.

[0064] In Fig. 9A, only the first rib 85a is formed onto the metal sheet 87. However, not only the first rib 85a, but also the second ribs 85b can be formed onto the metal sheet 87. (Sixth alternative)

[0065] Fig. 9B is a view corresponding to the cross-sectional view taken along the line VIII-VIII of Fig. 6D, which shows a vibration isolator 1f of a sixth alternative of the above-described embodiment. In this alternative, none of the end surfaces 27a of the protruding nose 27 is flat, but is provided with a projection, and stopper rubbers 95 of the vibration isolator 1f are shaped to correspond to the projection.

[0066] Specifically, a projection 27d projecting toward the first rib 95a is formed on a portion of the end surface 27a of the protruding nose 27, which corresponds to a first rib 95a of the stopper rubber 95. The first rib 95a facing the protruding nose 27 has the same dimension as second ribs 95b, 95b on both sides of the first rib 95a in the projecting direction thereof.

[0067] In this structure, when the vibration isolator 1f is fixed to the side frame 25, the first rib 95a is pre-pressed by the projection 27d of the projecting lug 27 and the opposing part 33, while a gap is formed between each of the second ribs 95b, 95b and the projecting lug 27. (Seventh Alternative)

[0068] Fig. 10A is a view corresponding to the cross-sectional view taken along the line XX of Fig. 6D, which shows a vibration isolator 1g of a seventh alternative of the above-described embodiment. The vibration isolator 1g has a holder of a shape different from the shape of the holder 31 of the vibration isolator 1 of the above-described embodiment. Specifically, the vibration isolator 1g has a pair of holders 101, 101, each having an L-shaped cross section. The holders 101, 101 are arranged to sandwich the protruding lug 27 in the vertical direction.

[0069] With this structure, the holders 101, 101 can be arranged with greater flexibility, and the position of a stopper rubber 35 provided on each of the holders 101 can be changed as needed. (Eighth alternative)

[0070] Fig. 10B is a view corresponding to the cross-sectional view taken along the line XX of Fig. 6D, which shows a vibration isolator 1h of an eighth alternative of the above-described embodiment. The vibration isolator 1h has a holder 111 of a shape different from the shape of the holder 31 of the vibration isolator 1 of the above-described embodiment. Specifically, a pair of opposing parts 113, 113 of the holder 111 are offset in a direction perpendicular to the direction in which the opposing parts 113, 113 face each other.

[0071] With this structure, even if the power train 23 is fixed to the vehicle at a position offset from peripheral components, the property of the stopper rubbers similar to that exerted in the vibration isolator 1 of the above-described embodiment can be obtained. (Ninth Alternative)

[0072] Fig. 10C is a view corresponding Fig. 6D, which shows a vibration isolator 1j of a ninth alternative of the above-described embodiment. The vibration isolator 1j has a holder 121 of a shape different from the shape of the holder 31 of the vibration isolator 1 of the above-described embodiment. Specifically, an angle α formed by each of the opposing parts 123 and a coupling part 127 can be changed as needed according to the installation conditions of the vibration isolator 1j. (Tenth Alternative)

[0073] Fig. 11A is a perspective view showing a stopper rubber 135 of a vibration isolator of a tenth alternative of the above-described embodiment. Fig. 11B is a front view showing the stopper rubber 135 of the vibration isolator of the tenth alternative of the above-described embodiment. Fig. 11C is a side view showing the stopper rubber 135 of the vibration isolator of the tenth alternative of the above-described embodiment. The stopper rubber 135 differs from the stopper rubber 35 of the vibration isolator 1 of the above-described embodiment in that the stopper rubber 135 is substantially disc-shaped.

[0074] Specifically, the stopper rubber 135 includes a disc-shaped base 135d disposed on the opposing part 33, a conical part 135a extending from the center of one of the surfaces of the base 135d facing an axial direction thereof, and an annular part 135b projecting from an outer peripheral edge of the base 135d in the axial direction. An annular recess 135c (a gap) is formed between the annular part 135b and the conical part 135a.

[0075] In this structure, the conical portion 135a is pre-pressed by the protruding lug 27 and the opposing portion 33. The annular portion 135b is spaced from the protruding lug 27, and the drive train 23 contacts the protruding lug 27 when the drive train 23 swings in the rolling direction. (Eleventh Alternative)

[0076] Fig. 12A and Fig. 12B are perspective views showing a vibration isolator 1m of an eleventh alternative of the above-described embodiment. Fig. 13A is a plan view showing the vibration isolator 1m, and Fig. 13B is a side view showing the vibration isolator 1m.

[0077] The vibration isolator 1m includes stop rubbers 145 of a shape different from the shape of the stop rubbers 35 of the vibration isolator 1 of the above-described embodiment. Other features of the vibration isolator 1m are essentially the same as those of the vibration isolator 1 and will not be described in detail below.

[0078] Like the stopper rubbers 35 of the vibration isolator 1 of the above-described embodiment, each of the stopper rubbers 145 of the vibration isolator 1m includes three ribs 145a, 145b, 145b arranged in a width direction of the opposing parts 33. Each of the ribs 145a, 145b extends linearly in a longitudinal direction of the opposing parts 33. The central rib 145a has a trapezoidal cross section like the first rib 35a of the above-described embodiment. The ribs 145b, 145b on both sides of the central rib 145a have a substantially rectangular cross section like the second ribs 35b of the above-described embodiment.

[0079] The three ribs 145a, 145b, 145b have the same dimensions in their protrusion direction. When the protruding lug 27 of the suspended drive train 23 is arranged between the stop rubbers 145, 145, gaps are formed between the ribs 145a, 145b, 145b of the stop rubbers and the end surfaces 27a of the protruding lug 27.

[0080] At one edge of the middle rib 145a of the three ribs 145a, 145b, 145b facing the coupling part 37 of the holder 31, a projection 145c (a pre-pressed part) is formed to protrude toward the opposing part 33 facing the middle rib 145a. The projection 145c extends linearly in the width direction of the opposing part 33 on a projecting end surface of the rib 145a. The projection 145c is pre-pressed by the projecting lug 27 and the opposing part 44, with the projecting lug 27 of the suspended power train 23 being arranged between the stopper rubbers 145, 145.

[0081] When mounting the vibration isolator 1m to the side frame 25, the vibration isolator 1m is brought closer to the side frame 25 from the rear side of the protruding lug 27. At this time, the projection 39 contacts the protruding lug 27 of the drive train 23 to determine the position of the vibration isolator 1 in the longitudinal direction. The projections 145c, 145c of the stopper rubbers 145, 145 position the center of the protruding lug 27 of the drive train 23 in the rolling direction to the center of the bracket 31. At the same time, the projections 145c are pre-pressed by the protruding lug 27 of the drive train 23 and the opposing parts 33. Thus, the center rib 145a is pre-pressed to a minimum degree.

[0082] When the power train 23 is actuated in this state, the protruding lug 27 vibrates in the rolling direction. Since the projections 145c are pre-compressed at an early stage of vibration, the protruding lug 27 rotates smoothly. However, since the degree of pre-compression is less than that of the vibration isolator 1 of the above-described embodiment, the protruding lug 27 rotates more than the protruding lug 27 of the vibration isolator 1. As the protruding lug 27 continues to rotate, the protruding lug 27 contacts the three ribs 145a, 145b, and 145b. Thus, compared with the above-described embodiment in which the protruding lug 27 contacts the two ribs 35b, 35b, the amount of vibration of the engine can be reduced while reducing the degree of pre-compression to reduce an initial spring constant. (Other embodiments)

[0083] In the above-described embodiment, the first rib 35a and the second ribs 35b, 35b of the stopper rubber 35 are provided integrally. However, the structure of the ribs is not limited to this, and the first rib 35a and the second ribs 35b, 35b may be provided independently.

[0084] In the above-described embodiment, the vibration isolator 1 is designed to reduce the vibration of the drive train 23 of the vehicle 3. However, the vibration isolator 1 is not limited to the vehicle drive train but can be used in a drive train of an industrial vehicle such as a forklift, a tractor, etc.

[0085] In the above-described embodiment, the protruding projection 27 extends obliquely downward from the outer peripheral edge of the drive train 23. However, the protruding projection 27 is not limited to this, and the protruding projection 27 may extend in a direction perpendicular to the principal axes of inertia X of the drive train 23 and intersecting the horizontal direction.

[0086] As described above, the disclosed technology can be used to prevent vibration of a powertrain mounted on a vehicle from being transmitted in a rolling direction to a vehicle body.

Claims

[1] Vibration isolator designed to reduce vibration of a drive train (23) mounted on a vehicle (3) in a direction about principal axes of inertia of the drive train (23), the vibration isolator (1) comprising: a pair of opposing members (33) fixed to a vehicle body of the vehicle (3) so as to be located on both sides of a projection (27) projecting from an outer peripheral edge of the power train (23) in a direction perpendicular to the principal axes of inertia to oppose each other in the direction around the principal axes of inertia; a pre-pressed part (35a) arranged on a part of each of the opposing elements (33) facing the projection (27) and pressed into contact with the projection (27) so as to be pre-pressed by the respective opposing element (33) and the projection (27) in the direction around the principal axes of inertia; and a contacting portion (35b) disposed on the part of each of the opposing members (33) facing the projection (27) to be spaced from the projection (27), and contacting the projection (27) when the drive train (23) swings in the direction around the principal axes of inertia. [2] Vibration isolator according to claim 1, wherein the principal axes of inertia extend in a horizontal direction, a projection direction of the projection (27) intersects the horizontal direction and the pre-pressed parts (35a) and the contacting parts (35b) extend in a direction perpendicular to the projection (27). [3] Vibration isolator according to claim 2, wherein Parts (27a) of the projection (27) facing the opposing elements (33) are flat along the projection direction of the projection (27) and the pre-pressed parts (35a) extend so that they are closer to the projection (27) than the contacting parts (35b). [4] A vibration isolator according to claim 3, wherein a gap (35c) is formed between the pre-pressed part (35a) and the contacting part (35b) arranged on the same opposing member (33). [5] Vibration isolator according to claim 1, wherein one end of one of the opposing elements (33) and one end of the other opposing element (33) are coupled at one side in a direction of the principal axes of inertia by a coupling element (37) and a projection (39) for positioning the projection (27) in the direction of the main axes of inertia is formed on a part of the coupling element (37) facing the projection (27).

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