Vibration isolation unit

Abstract

To provide a vibration-damping unit that can prevent the stopper from falling off. [Solution] A through hole 18a is formed through a plate-shaped first mounting portion 18 that rises from the outer peripheral surface of the outer member 12, and the stopper 30 is attached to the outer member 12 by inserting an elastic projection 34 protruding from the peripheral end portion 33 of the stopper 30 into the through hole 18a. The tip of the elastic projection 34 protrudes through the through hole 18a to one side A1 in the circumferential direction from the first mounting portion 18, and a retaining projection 35 extends from that tip along the first mounting portion 18. This prevents the elastic projection 34 from coming out of the through hole 18a. As a result, the detachment of the stopper 30 from the outer member 12 can be prevented when transporting the vibration isolation unit 10.

Description

Technical Field

[0001] The present invention relates to a vibration isolation unit, and particularly to a vibration isolation unit capable of suppressing the dropout of a stopper.

Background Art

[0002] Conventionally, a vibration isolation unit that suppresses vibration transmission while connecting a power unit side such as an engine and a vehicle body side is known. Some of these vibration isolation units include a vibration isolation device in which an axial inner member and a cylindrical outer member are connected by an elastic vibration isolation base, and an elastic stopper attached to the vibration isolation device. For example, the inner member is attached to the power unit side, and the outer member is attached to the vehicle body side.

[0003] The stopper of Patent Document 1 is for buffering the collision between both axial ends of the outer member and a bracket on the power unit side attached to the inner member. The stopper is attached to the inner member by fitting both axial ends of the inner member into through-holes penetrating the stopper in the plate thickness direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above prior art, since only the axial end of the inner member is fitted into the through-hole of the stopper, there is a problem that the stopper is likely to drop off from the inner member during transportation of the vibration isolation unit before the inner member is fixed to the bracket.

[0006] This invention was made to solve the above-mentioned problems and aims to provide a vibration-damping unit that can suppress the detachment of the stopper. [Means for solving the problem]

[0007] To achieve this objective, the vibration isolation unit of the present invention comprises an axial inner member, a cylindrical outer member surrounding the inner member, an elastic vibration isolation base connecting the outer peripheral surface of the inner member and the inner peripheral surface of the outer member, and an elastic stopper attached to the outer member. The outer member includes a plate-shaped first mounting portion rising from the outer peripheral surface of the outer member, and a through hole is formed through the first mounting portion in the thickness direction of the plate. The stopper includes a circumferential surface portion covering a part of the outer peripheral surface of the outer member in the circumferential direction, a circumferential end portion provided on one side of the circumferential surface portion, an elastic projection protruding from the circumferential end portion and inserted into the through hole, and a retaining projection extending along the first mounting portion from the tip of the elastic projection that protrudes to the one side in the circumferential direction beyond the first mounting portion through the through hole.

[0008] Another vibration isolation unit of the present invention comprises an axial inner member, a cylindrical outer member surrounding the inner member, an elastic vibration isolation base connecting the outer circumferential surface of the inner member and the inner circumferential surface of the outer member, and an elastic stopper attached to the outer member having a circumferential surface portion that covers a part of the outer circumferential surface of the outer member, wherein the stopper has a through hole formed through one side in the circumferential direction and a mounting hole formed through the other side in the circumferential direction, and the outer member comprises a mounting projection that protrudes from the outer circumferential surface of the outer member and is inserted into the through hole, a second mounting portion that protrudes from the outer circumferential surface of the outer member and is inserted into the mounting hole, and an overhang that extends from the tip of the second mounting portion toward the other side in the circumferential direction, wherein a fixing member is attached to the tip of the mounting projection, which is larger than the through hole to fix the stopper to the outer member. [Effects of the Invention]

[0009] According to the vibration isolation unit described in claim 1, a through hole is formed through a plate-shaped first mounting portion that rises from the outer peripheral surface of the outer member, and the stopper is attached to the outer member by inserting an elastic projection protruding from the peripheral end of the stopper into the through hole. The tip of the elastic projection protrudes through the through hole to one side in the circumferential direction from the first mounting portion, and a retaining projection extends from that tip along the first mounting portion. This prevents the elastic projection from coming out of the through hole. As a result, the detachment of the stopper from the outer member can be prevented during transportation of the vibration isolation unit.

[0010] Furthermore, the stopper includes a circumferential portion that covers a part of the outer surface of the outer member in the circumferential direction. When such a stopper is attached to the inner member as in the conventional technology, the relative displacement between the inner member and the outer member due to the deformation of the vibration-damping base may cause the stopper to stretch and deform, potentially reducing the durability of the stopper. In contrast, in this vibration-damping unit, the stopper is attached to the outer member, so the stretching deformation of the stopper described above does not basically occur, and the durability of the stopper can be improved.

[0011] The vibration isolation unit according to claim 2 provides the following effects in addition to those of the vibration isolation unit according to claim 1. A mounting hole is formed through the other circumferential portion of the stopper. A second mounting portion protruding from the outer surface of the outer member is inserted into the mounting hole, and an overhang extends from the tip of the second mounting portion to the other circumferential side. Thus, one side of the stopper is attached to the outer member by insertion of an elastic projection and a retaining projection, and the other side of the stopper is attached to the outer member by hooking onto the second mounting portion and the overhang. This prevents the circumferential portion of the stopper from vibrating in a way that it rotates, for example, with the first mounting portion as the pivot point, by hooking onto the second mounting portion and the overhang. Furthermore, it is possible to achieve both relatively strong attachment by insertion of an elastic projection and a retaining projection and improved workability of attachment by hooking.

[0012] The vibration isolation unit according to claim 3 provides the following effects in addition to those of the vibration isolation unit according to claim 1: A mounting projection protruding from the outer peripheral surface of the outer member is inserted into a through-hole formed in one side of the stopper. A fixing member larger than the through-hole is attached to the tip of the mounting projection, thereby fixing one side of the stopper to the outer member. This prevents the stopper from falling off the outer member during transportation of the vibration isolation unit.

[0013] Furthermore, the stopper includes a circumferential portion that covers a part of the outer surface of the outer member in the circumferential direction. When such a stopper is fixed to the inner member as in the conventional technology, the relative displacement between the inner member and the outer member due to the deformation of the vibration-damping base may cause the stopper to stretch and deform, potentially reducing the durability of the stopper. In contrast, in this vibration-damping unit, since the stopper is attached to the outer member, the stretching deformation of the stopper described above does not basically occur, and the durability of the stopper can be improved.

[0014] Furthermore, a second mounting portion, which protrudes from the outer circumferential surface of the outer member, is inserted into a mounting hole formed through the other side of the stopper. A protruding portion extends from the tip of the second mounting portion to the other side in the circumferential direction. As a result, the other side of the stopper is hooked onto the second mounting portion and the protruding portion and attached to the outer member. Therefore, vibration of the circumferential surface of the stopper, for example, by rotating around the first mounting portion as a pivot point, can be suppressed by hooking onto the second mounting portion and the protruding portion. In addition, it is possible to achieve both relatively strong attachment by the fixing member and improved workability of attachment by hooking.

[0015] The vibration isolation unit according to claim 4 provides the following effects in addition to the effects of the vibration isolation unit according to claim 2 or 3. The stopper comprises a pair of circumferential extensions extending from the circumferential surface to the other side in the circumferential direction and spaced apart from each other in the axial direction of the outer member, and a pair of axial extensions that are connected to each of the pair of circumferential extensions and spaced apart from each other in the circumferential direction. The portion surrounded by the pair of circumferential extensions and the pair of axial extensions is the mounting hole. In this way, the vicinity of the mounting hole of the stopper is formed in a ladder shape. This makes it easier to insert the protruding portion and the second mounting portion into the mounting hole while extending the ladder-shaped portion on the other side of the stopper after attaching one side of the stopper to the outer member. That is, with one side of the stopper attached to the outer member, it is easier to hook the other side of the stopper onto the protruding portion and the second mounting portion. Thus, the work of attaching the stopper to the outer member can be made easier.

[0016] The vibration isolation unit according to claim 5 provides the following effects in addition to the effects of the vibration isolation unit according to claim 1 or 2. The peripheral end comprises a first surface from which an elastic projection protrudes and a second surface opposite to the first surface. The bottom of a closed hole opening to this second surface is located inside the elastic projection. This makes it easier to apply force in the insertion direction to the elastic projection when inserting the elastic projection and the retaining projection into the through hole, for example by inserting a rod into the closed hole, touching the tip of the rod to the bottom, and then pushing the rod further. Therefore, the insertability of the elastic projection and the retaining projection into the through hole can be improved.

[0017] The vibration isolation unit according to claim 6 provides the following effects in addition to those of the vibration isolation unit according to claim 5. When a rod with its tip pressed against the bottom of a dead hole is pushed in, the elastic projection and the retaining projection on the circumferential end side of the bottom are tensilely deformed in the axial direction of the through hole, reducing in diameter in the radial direction of the through hole. Since the bottom of the dead hole is located on the tip side of the elastic projection than the end face on the circumferential end side of the retaining projection, the reduction in diameter during pushing makes it easier for the end face to pass through the through hole. Therefore, the insertability of the elastic projection and the retaining projection into the through hole can be further improved.

[0018] According to the vibration isolator unit described in claim 7, in addition to the effects achieved by the vibration isolator unit described in any one of claims 1 to 3, the following effects are achieved. The stopper includes a pair of end surfaces that project radially inward of the outer member from both axial edges of the circumferential surface so as to cover a part of both axial end surfaces of the outer member. Due to such a pair of end surfaces and the circumferential surface, the circumferential cross-section of the stopper is formed in a U-shape, so that the rigidity of the stopper can be ensured. As a result, it is possible to suppress the deformation of the stopper away from the outer peripheral surface of the outer member in the radial direction at a position circumferentially separated from the attachment position of the outer member and the stopper (such as the vicinity of the first attachment portion). As a result, it is possible to make it difficult to generate a hitting sound associated with the re-contact between the outer peripheral surface of the outer member and the stopper.

Brief Description of Drawings

[0019] [Figure 1] It is a perspective view of the vibration isolator unit in the first embodiment. [Figure 2] It is an exploded perspective view of the vibration isolator unit. [Figure 3] It is a cross-sectional view of the vibration isolator unit. [Figure 4] It is an end face view of the cut portion of the vibration isolator unit along line IV-IV in FIG. 3. [Figure 5] It is an exploded perspective view of the vibration isolator unit in the second embodiment. [Figure 6] It is an exploded perspective view of the vibration isolator unit in the third embodiment. [Figure 7] It is a cross-sectional view of the vibration isolator unit.

Modes for Carrying Out the Invention

[0020] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. FIGURE 1 shows a vibration isolator unit 10 in the first embodiment. FIGURE 2 shows an exploded perspective view of the vibration isolator unit 10. FIGURE 3 shows a cross-sectional view of the vibration isolator unit 10 perpendicular to the axis C of the inner member 12. FIGURE 4 shows an end face view of the cut portion of the vibration isolator unit 10 along line IV-IV in FIGURE 3. Note that the cross-section in FIGURE 3 is a cross-section passing through the axis of the elastic protrusion 34 described later.

[0021] The arrows U, D, L, R, F, and B in each drawing indicate the upward, downward, leftward, rightward, forward, and backward directions of the vibration isolation unit 10, respectively. Note that the vertical, horizontal, and front-back directions of the vibration isolation unit 10 do not necessarily coincide with the vertical, horizontal, and front-back directions of the vehicle on which the vibration isolation unit 10 is mounted.

[0022] As shown in FIG. 1, the vibration isolation unit 10 is an engine mount that suppresses vibration transmission while connecting a power unit (not shown) such as an engine or a motor and a vehicle body (not shown). The vibration isolation unit 10 includes a vibration isolation device 11 that connects the power unit side and the vehicle body side, and a stopper 30 that covers a part of the vibration isolation device 11.

[0023] The vibration isolation device 11 includes a shaft-shaped inner member 12, a cylindrical outer member 13 that surrounds the outer peripheral side of the inner member 12, and a vibration isolation base 14 that connects the outer peripheral surface of the inner member 12 and the inner peripheral surface of the outer member 13. The vibration isolation base 14 is made of an elastic body such as rubber or thermoplastic elastomer, and connects the inner member 12 and the outer member 13 at four locations in the circumferential direction.

[0024] The inner member 12 is a cylindrical member formed along the axis C, and is made of a rigid material such as a steel material or an aluminum alloy. The direction of the axis C of the inner member 12 (axial direction) coincides with the front-back direction of the vibration isolation device 11. The inner peripheral surface of the inner member 12 is circular with the axis C as the center in a cross section perpendicular to the axis C of the inner member 12. The outer peripheral surface of the inner member 12 is formed in a substantially hexagonal shape in a cross section perpendicular to the axis C.

[0025] As shown in FIG. 4, the inner member 12 is connected to the power unit side via a bracket 2. The bracket 2 includes a pair of side portions 4 facing each other in the plate thickness direction, and a connecting portion 5 that connects the pair of side portions 4. The connecting portion 5 is fixed to the power unit side.

[0026] The inner member 12 is sandwiched between a pair of side parts 4 in the front-rear direction (axis C direction), and the connecting part 5 is located on the upper left side relative to the outer member 13. In this state, bolts 7 are inserted into bolt insertion holes 6 provided in the side parts 4 and the inner circumference of the inner member 12, and nuts 8 are fastened to the bolts 7, thereby fixing the inner member 12 to the bracket 2.

[0027] As shown in Figures 2 and 3, the outer member 13 comprises a cylindrical portion 15 to which the vibration-damping base 14 is connected, a cylindrical thick portion 16 into which the cylindrical portion 15 is press-fitted, and a fixing portion 17 for fixing the thick portion 16 to the vehicle body. The cylindrical portion 15 is a cylindrical member centered on axis C and is made of a rigid material such as steel or aluminum alloy. The vibration-damping base 14 is vulcanized and bonded to the inner circumferential surface of this cylindrical portion 15 and the outer circumferential surface of the inner member 12.

[0028] The thickened cylindrical portion 16 is a cylindrical member made of aluminum alloy, formed with a thicker wall than the cylindrical portion 15. The front-to-rear dimensions of the thickened cylindrical portion 16 and the cylindrical portion 15 are approximately the same and smaller than the front-to-rear dimensions of the inner member 12. The front-to-rear end faces of the inner member 12 are located outside the front-to-rear end faces of the thickened cylindrical portion 16 and the cylindrical portion 15 in the front-to-rear direction.

[0029] A first mounting portion 18 rises upward from the upper side of the outer circumferential surface of the cylindrical thickness portion 16. The first mounting portion 18 is a plate-shaped portion with the left-right direction as the plate thickness direction. Two through holes 18a are formed through the first mounting portion 18 in the direction of plate thickness. The two through holes 18a are aligned in the front-rear direction and are formed identically to each other.

[0030] A second mounting portion 19 rises from the lower left side of the outer surface of the cylindrical thickness portion 16, extending to the left. The second mounting portion 19 is a plate-shaped portion with the plate thickness direction in the vertical direction. A plate-shaped overhang 20 extends downward from the tip (left end) of the second mounting portion 19. Of the circumferential directions of the outer member 13, the direction from the second mounting portion 19 toward the first mounting portion 18 is designated as one side A1, and the direction from the first mounting portion 18 toward the second mounting portion 19 is designated as the other side A2.

[0031] The fixing portion 17 is integrally molded with the cylindrical thickness portion 16 so as to protrude downward to the right from the outer surface of the cylindrical thickness portion 16. The outer member 13 is fixed to the vehicle body side by multiple threaded portions 17a provided on the fixing portion 17. The shape of the fixing portion 17 may be changed as appropriate, as long as it can fix the outer member 13 to the vehicle body side.

[0032] As shown in Figures 2 and 4, the stopper 30 is designed to cushion the collision between the outer member 13 and the bracket 2 when they are displaced relative to each other due to the deformation of the vibration-damping base 14. The stopper 30 is made of an elastic material such as rubber or thermoplastic elastomer. In the following description of the stopper 30, the circumferential direction of the outer member 13 will be simply referred to as the circumferential direction, and the radial direction of the outer member 13 will be simply referred to as the radial direction.

[0033] The stopper 30 comprises a circumferential surface portion 31 that covers a part of the outer surface of the outer member 13 (cylindrical thickness portion 16) in the circumferential direction, a pair of end surface portions 32 that protrude radially inward (towards axis C) from both front-rear edges of the circumferential surface portion 31, a circumferential end portion 33 provided on one side A1 in the circumferential direction of the circumferential surface portion 31, a pair of circumferential extension portions 36 that extend from the circumferential surface portion 31 to the other side A2 in the circumferential direction and are separated from each other in the front-rear direction, and a pair of axial extension portions 37 that are spanned between the pair of circumferential extension portions 36 and are separated from each other in the circumferential direction.

[0034] The circumferential portion 31 is a plate-shaped part that covers a predetermined area A2 on the outer circumferential surface of the outer member 13, on the other side of the first mounting portion 18. That is, the circumferential portion 31 is provided in the portion where the outer member 13 and the bracket 2 face each other in the radial direction. This circumferential portion 31 can cushion the collision when the outer member 13 and the bracket 2 are displaced relative to each other in the radial direction.

[0035] The pair of end faces 32 are plate-like portions that cover the upper left portion of both end faces of the outer member 13 in the front-rear direction. In other words, the end faces 32 are provided at the portion where the outer member 13 and the bracket 2 face each other in the front-rear direction. These end faces 32 can cushion collisions when the outer member 13 and the bracket 2 are displaced relative to each other in the front-rear direction.

[0036] As shown in Figures 2 and 3, the peripheral end portion 33 is a plate-like portion that rises upward from one end A1 of the peripheral surface portion 31 and is formed substantially parallel to the first mounting portion 18. The peripheral end portion 33 comprises a first surface 33a facing the first mounting portion 18 and towards one side A1, and a second surface 33b that is opposite to the first surface 33a and faces the other side A2.

[0037] Two elastic protrusions 34 protrude almost vertically from the first surface 33a of the peripheral end portion 33. The two elastic protrusions 34 are formed in the same approximately cylindrical shape and are aligned in the front-to-back direction. These two elastic protrusions 34 are inserted into the two through holes 18a of the first mounting portion 18. This attaches the stopper 30 to the outer member 13.

[0038] From the tip of the elastic projection 34 that protrudes to one side A1 from the first mounting portion 18 through the through hole 18a, a retaining projection 35 extends radially along the first mounting portion 18. This retaining projection 35 prevents the elastic projection 34 from coming out of the through hole 18a. As a result, the stopper 30 can be prevented from falling off the outer member 13, such as during transport when the vibration damping unit 10 is not attached to the vehicle body or bracket 2.

[0039] Furthermore, two elastic protrusions 34, each provided with a retaining projection 35, are inserted into two through holes 18a. This ensures that even if one elastic protrusion 34 breaks, the other elastic protrusion 34 and the retaining projection 35 can prevent the stopper 30 from falling out of the outer member 13. The same applies when there are three or more elastic protrusions 34 with retaining projections 35, and three or more through holes 18a into which they are inserted.

[0040] Conventionally, the axial end of the inner member 12 was fitted into a hole formed through the stopper, so attaching the inner member 12 to the bracket 2 prevented the stopper from falling off. In contrast, in this embodiment, the stopper 30 is attached to the outer member 13, so there is a risk that the stopper 30 may fall off even when the vibration damping unit 10 is attached to the vehicle body or bracket 2. However, the aforementioned retaining projection 35 can easily prevent the stopper 30 from falling off.

[0041] Furthermore, if the stopper is attached to the inner member 12 as in the conventional method, and the stopper has a circumferential surface portion 31, the stopper may stretch and deform due to the relative displacement between the inner member 12 and the outer member 13 caused by the deformation of the vibration-damping base 14, potentially reducing the durability of the stopper. In contrast, in this embodiment, the stopper 30 is attached to the outer member 13, so the stretching deformation of the stopper 30 described above does not basically occur, and the durability of the stopper 30 can be improved.

[0042] The retaining projection 35 is provided around the entire circumference of the elastic projection 34. The end face 35a of the retaining projection 35 on the circumferential end 33 side (first mounting portion 18 side) protrudes in a stepped manner, approximately perpendicular to the outer circumferential surface of the elastic projection 34. As a result, the end face 35a catches on the first mounting portion 18 around the through hole 18a, further suppressing the elastic projection 34 from coming out of the through hole 18a.

[0043] Furthermore, the outer circumferential surface of the retaining projection 35 is provided with an inclined surface 35b that tapers in diameter from the end face 35a towards the tip of the elastic projection 34. This makes it easier to insert the elastic projection 34 and the retaining projection 35 into the through hole 18a until the end face 35a exceeds the through hole 18a. In other words, the ease of inserting the elastic projection 34 and the retaining projection 35 into the through hole 18a can be improved.

[0044] A bottomed hole 33c is formed inside the peripheral end 33 and the elastic projection 34. The bottomed hole 33c is a cylindrical hole, with one end opening to the second surface 33b. The bottom 33d of the other end of the bottomed hole 33c is located inside the elastic projection 34. This makes it easier to apply force to the elastic projection 34 in the insertion direction when inserting the elastic projection 34 and the retaining projection 35 into the through hole 18a, for example, by inserting a rod into the bottomed hole 33c, touching the tip of the rod to the bottom 33d, and then pushing the rod further. Furthermore, the way in which the elastic projection 34 etc. deforms can be controlled compared to when the elastic projection 34 etc. is inserted into the through hole 18a while pressing the second surface 33b. As a result, the ease of inserting the elastic projection 34 etc. into the through hole 18a can be improved.

[0045] Furthermore, when a rod with its tip pressed against the bottom 33d of the bottomed hole 33c is pushed in, the elastic projection 34 and the retaining projection 35 on the circumferential end 33 side of the bottom 33d are tensilely deformed in the axial direction of the through hole 18a, causing them to shrink in the radial direction of the through hole 18a. Since the bottom 33d of the bottomed hole 33c is located on the tip side of the elastic projection 34 than the end face 35a of the retaining projection 35, the shrinking in diameter during pushing makes it easier for the end face 35a to pass through the through hole 18a. Therefore, the insertability of the elastic projection 34 and the retaining projection 35 into the through hole 18a can be further improved.

[0046] The distance L1 in the left-right direction from the first surface 33a of the peripheral end portion 33 to the end surface 35a of the retaining projection 35 is greater than the thickness L2 in the plate thickness direction (left-right direction) of the first mounting portion 18 sandwiched between them. In particular, it is preferable that the difference between the distance L1 and the thickness L2 is about 1 mm or more. As a result, when the first surface 33a is pressed against the first mounting portion 18, even if the elastic projection 34 is compressed by about 1 mm from its free length in the left-right direction, the end surface 35a will be located on one side A1 of the first mounting portion 18. Therefore, for example, even when inserting the elastic projection 34 etc. into the through hole 18a by pushing the second surface 33b without inserting a rod into the bottomed hole 33c, the end surface 35a will easily pass over the through hole 18a.

[0047] Furthermore, if the difference between the distance L1 and the thickness L2 is approximately 1 mm or more, it becomes easier to create a curved surface at the corner between the end face 35a and the outer circumferential surface of the elastic projection 34 that is less likely to interfere with the first mounting portion 18. As a result, when manufacturing the stopper 30 using a mold, even if the retaining projection 35 needs to be forcibly removed from the mold, the curved surface at the corner makes it easier to remove it forcibly.

[0048] Furthermore, it is preferable that the difference between the distance L1 and the thickness L2 is approximately 2 mm or less. This reduces the amount by which the first mounting portion 18 can move relative to the first surface 33a and the end surface 35a in the left-right direction. As a result, vibration of one side A1 of the stopper 30 in the left-right direction relative to the outer member 13 can be suppressed, and the generation of friction noises and impact noises associated with such vibrations can be suppressed.

[0049] The stopper 30, which is attached to the outer member 13 by elastic protrusions 34, has a circumferential cross-section that is U-shaped, formed by a circumferential surface portion 31 and a pair of end surfaces 32. Furthermore, the circumferential cross-section of the stopper 30 is U-shaped not only at the mounting position but also along the entire circumferential length of the circumferential surface portion 31, ensuring the rigidity of the stopper 30. This prevents the stopper 30 from deforming radially away from the outer surface of the outer member 13 at a position circumferentially away from the above-mentioned mounting position (such as near the elastic protrusions 34). As a result, it is possible to reduce the occurrence of knocking noises associated with re-contact between the outer surface of the outer member 13 and the stopper 30.

[0050] The pair of circumferential extensions 36 extend parallel to the other side A2 (downward side) from the end of the other side A2 of the circumferential surface 31. The pair of axial extensions 37 are spanned parallel to the lower end of the circumferential extension 36 and approximately the center of the circumferential direction of the circumferential extension 36. These pair of circumferential extensions 36 and the pair of axial extensions 37 form a ladder-like structure on the other side A2 (lower end side) of the stopper 30.

[0051] Furthermore, a roughly rectangular mounting hole 38 is formed on the other side A2 of the stopper 30 by a portion surrounded by a pair of circumferential portions 36 and a pair of axial portions 37. The mounting hole 38 is formed to be slightly larger than the second mounting portion 19 of the vibration isolation device 11, that is, to be large enough to insert the second mounting portion 19. The mounting hole 38 is also large enough to insert the protruding portion 20.

[0052] When the second mounting portion 19 is inserted into the mounting hole 38, the protruding portion 20 catches on the axial extension portion 37 on the lower side of the mounting hole 38, making it difficult for the second mounting portion 19 to come out of the mounting hole 38. As a result, one side A1 of the stopper 30 is attached to the outer member 13 by the insertion of the elastic projection 34, etc., and the other side A2 of the stopper 30 is attached to the outer member 13 by being caught on the second mounting portion 19 and the protruding portion 20. This further prevents the stopper 30 from falling off the outer member 13 when transporting the vibration isolation unit 10.

[0053] In addition, it is possible to achieve both relatively firm attachment by inserting elastic protrusions 34, etc., and improved workability of attachment by hooking. Furthermore, the vibration of the circumferential portion 31 of the stopper 30, for example, by rotating around the first attachment portion 18 as a pivot point, can be suppressed by hooking onto the second attachment portion 19 and the protruding portion 20. Consequently, the generation of knocking noises associated with such vibrations can be suppressed.

[0054] The area near the mounting hole 38 of the stopper 30 is ladder-shaped and therefore more easily deformed than the circumferential surface 31 and the end surface 32. Therefore, when attaching the stopper 30 to the outer member 13, after attaching the part A1 on one side of the stopper 30 to the outer member 13, it is easier to insert the protruding part 20 and the second mounting part 19 into the mounting hole 38 while extending the ladder-shaped part A2 on the other side of the stopper 30. In other words, with the part A1 on one side of the stopper 30 attached to the outer member 13, it is easier to hook the part A2 on the other side of the stopper 30 onto the protruding part 20 and the second mounting part 19. Therefore, the work of attaching the stopper 30 to the outer member 13 can be made easier.

[0055] Furthermore, when the stopper 30 deforms due to vibration input to the vibration isolation unit 10, the ladder-shaped portion easily absorbs the deformation, suppressing deformation of the circumferential portion 31 and end portion 32, which mainly have a cushioning function. As a result, it is possible to suppress changes in cushioning characteristics and the generation of abnormal noises that occur due to the deformation of the stopper 30.

[0056] Next, the second embodiment will be described with reference to Figure 5. In the first embodiment, the case in which the other side A2 of the stopper 30 is attached to the outer member 13 by hooking it onto the second mounting portion 19 and the protruding portion 20 was described. In contrast, the second embodiment will describe the case in which the other side A2 of the stopper 30 is attached to the outer member 13 using a fixing member 50. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted below. Also, if the shape or dimensions differ only slightly between the first and second embodiments, they will be considered identical parts and their descriptions will be omitted.

[0057] Figure 5 is an exploded perspective view of the vibration isolation unit 40 in the second embodiment. The vibration isolation unit 40 comprises a vibration isolation device 41 that connects the power unit side and the vehicle body side, a stopper 30 that covers a part of the vibration isolation device 41, and a fixing member 50 for fixing the stopper 30 to the vibration isolation device 41.

[0058] The vibration isolation device 41 differs from the vibration isolation device 11 in the first embodiment in that the protruding portion 20 is omitted, and two screw holes 42 are provided side by side in the front-to-back direction at the tip (left end) of the second mounting portion 19. The screw holes 42 are formed substantially perpendicular to the tip of the second mounting portion 19 (extending in the left-to-right direction), and internal threads are provided on the inner circumferential surface. The other parts of the vibration isolation device 41 are configured the same as in the first embodiment.

[0059] Since the vibration isolation device 41 does not have an overhang 20, if the second mounting portion 19 is simply inserted into the mounting hole 38 of the stopper 30, there is a risk that the second mounting portion 19 may easily come out of the mounting hole 38. The fixing member 50 is a member that prevents this coming out and fixes the other side A2 of the stopper 30 to the outer member 13.

[0060] The fixing member 50 is a rod-shaped member made of a rigid material such as steel or aluminum alloy. The fixing member 50 comprises a plate portion 51 that extends in the front-rear direction and is perpendicular to the left-right direction, and substantially octagonal weight portions 52 provided at both the front and rear ends of the plate portion 51.

[0061] The plate portion 51 has two bolt insertion holes 53 that are aligned in the front-to-back direction. The fixing member 50 is attached to the outer member 13 by overlapping the plate portion 51 with the tip of the second mounting portion 19 and fitting the two bolts 56, each inserted into the bolt insertion holes 53, into the screw holes 42 of the second mounting portion 19.

[0062] Since the fixing member 50 is sufficiently larger than the mounting hole 38 into which the second mounting portion 19 is inserted, the second mounting portion 19 is less likely to come out of the mounting hole 38. In other words, the fixing member 50 fixes the other side A2 of the stopper 30 to the outer member 13. This prevents the stopper 30 from falling off the outer member 13 during transportation of the vibration isolation unit 40. Furthermore, the fixing member 50 prevents the stopper 30 from vibrating in a way that causes it to rotate, for example, around the first mounting portion 18 as a pivot point, thereby suppressing the generation of knocking noises associated with such vibrations.

[0063] The area near the mounting hole 38 of the stopper 30 (part of the circumferential portion 36) is sandwiched between the fixing member 50 and the outer circumferential surface of the outer member 13. This further suppresses the vibration of the stopper 30 so as to rotate around the first mounting portion 18 as a pivot point, by fixing it with the fixing member 50.

[0064] The fixing member 50 is a mass member for adjusting the resonant frequency of the outer member 13 to which it is attached, and a weight portion 52 is provided to ensure mass. The stopper 30 can be fixed to the outer member 13 by the fixing member 50 which is a repurposed mass member. Therefore, the structure of the vibration isolation unit 40 can be simplified, and the cost increase associated with providing the fixing member 50 can be suppressed.

[0065] Next, a third embodiment will be described with reference to Figure 6. In the first embodiment, a case was described in which one side A1 of the stopper 30 is attached to the outer member 13 by insertion into the through hole 18a of the first mounting portion 18. In contrast, in the third embodiment, a case will be described in which one side A1 of the stopper 65 is attached to the outer member 13 using a fixing member 70. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions will be omitted below.

[0066] Figure 6 is an exploded perspective view of the vibration isolation unit 60 in the third embodiment. Figure 7 is a cross-sectional view of the vibration isolation unit 60. The cross-section in Figure 7 is a cross-section perpendicular to axis C, passing through the center of the inner member 12 and the outer member 13 in the direction of axis C. The vibration isolation unit 60 comprises a vibration isolation device 61 that connects the power unit side and the vehicle body side, a stopper 65 that covers a part of the vibration isolation device 61, and a fixing member 70 for fixing the stopper 65 to the vibration isolation device 61.

[0067] The vibration isolation device 61 is modified from the vibration isolation device 11 in the first embodiment by omitting the first mounting portion 18 and providing a mounting projection 62 in its place. All other parts of the vibration isolation device 61 are configured the same as in the first embodiment. The stopper 65 is modified from the stopper 30 in the first embodiment by omitting the circumferential end portion 33, elastic projection 34, and retaining projection 35, and providing a through hole 66 in their place. All other parts of the stopper 65 are configured the same as in the first embodiment.

[0068] The mounting projection 62 protrudes upward from the upper side of the outer circumferential surface of the outer member 13 (cylindrical thickness portion 16). The mounting projection 62 is a cylindrical portion with a screw hole 63 formed at its tip (upper end). Two of these mounting projections 62 are provided side by side in the front-to-back direction and are formed identically to each other.

[0069] The through-hole 66 is a hole formed vertically through one side A1 of the circumferential surface portion 31 of the stopper 65. The through-hole 66 is formed in an elongated oval shape that extends in the circumferential direction. The through-hole 66 is formed to be slightly larger than the mounting projection 62, that is, to be large enough to allow the mounting projection 62 to be inserted. Two through-holes 66 are provided side by side in the front-to-back direction so that two mounting projections 62, which are aligned in the front-to-back direction, can be inserted into each of them.

[0070] However, if the mounting projection 62 is simply inserted into the through-hole 66, there is a risk that the mounting projection 62 may easily come out of the through-hole 66. The fixing member 70 is a member that prevents this coming out and fixes one side A1 of the stopper 65 to the outer member 13.

[0071] The fixing member 70 is a roughly rectangular parallelepiped made of a rigid material such as steel or aluminum alloy. Flanges 71 protrude from the center of the vertical direction on both the front and rear surfaces of the fixing member 70.

[0072] The flange 71 is a plate-shaped portion that is vertical in the vertical direction, with a bolt insertion hole 72 formed through its center. The fixing member 70 is attached to the outer member 13 by overlapping the flange 71 with the tip of the mounting projection 62 and fitting the bolt 76 inserted into the bolt insertion hole 72 into the threaded hole 63 of the mounting projection 62.

[0073] Since the fixing member 70 is sufficiently larger than the insertion hole 66 into which the mounting projection 62 is inserted, the mounting projection 62 is less likely to come out of the insertion hole 66. In other words, the fixing member 70 fixes one side A1 of the stopper 65 (near the insertion hole 66) to the outer member 13. This prevents the stopper 65 from falling off the outer member 13, such as during transport when the vibration damping unit 60 is not attached to the vehicle body or power unit.

[0074] In particular, in this embodiment, the fixing member 70 is attached so as to span across the two mounting protrusions 62, making it more difficult for the mounting protrusions 62 to come out of the insertion hole 66. As a result, the detachment of the stopper 65 from the outer member 13 during transportation and other situations can be further suppressed.

[0075] Thus, in addition to the fixing member 70 fixing one side A1 of the stopper 65 to the outer member 13, the other side A2 of the stopper 65 is hooked onto the second mounting portion 19 and the overhang portion 20 and attached to the outer member, similar to the first embodiment. As a result, the detachment of the stopper 65 from the outer member 13 can be further suppressed when transporting the vibration isolation unit 60.

[0076] Furthermore, vibration of the circumferential portion 31 of the stopper 65, for example, by pivoting around the fixing member 70, can be suppressed by hooking it onto the second mounting portion 19 and the protruding portion 20. In addition, it is possible to achieve both relatively strong mounting by the fixing member 70 and improved workability of mounting by hooking.

[0077] The fixing member 70 is a mass member used to adjust the resonant frequency of the outer member 13 to which it is attached, and extends vertically from the flange 71 to ensure sufficient mass. By using such a mass member as the fixing member 70, the stopper 65 can be fixed to the outer member 13, thereby simplifying the structure of the vibration isolation unit 60 and suppressing the cost increase associated with providing the fixing member 70.

[0078] With the stopper 65 fixed to the outer member 13 by the fixing member 70, the stopper 65 is sandwiched between the lower surface 73 of the fixing member 70 and the outer circumferential surface of the outer member 13. This suppresses the movement of the stopper 65 in response to vibrations of the vehicle to which the vibration damping unit 60 is attached. Specifically, it suppresses the vertical vibration of the stopper 65 along the mounting projection 62 and the sliding of the stopper 65 along the outer circumferential surface of the outer member 13. As a result, the generation of knocking and rubbing noises between the stopper 65 and the vibration damping device 61, fixing member 70, etc., can be suppressed.

[0079] In the portion where the stopper 65 is sandwiched, the dimension W between the lower surface 73 of the fixing member 70 and the outer peripheral surface of the outer member 13 is the same as the thickness of the stopper 65 in the unloaded state (free length). Note that this "same" does not necessarily mean exactly the same. Taking into account errors, it is said to be "same" if the difference between dimension W and the thickness of the stopper 65 in the unloaded state is 1 mm or less. Alternatively, to ensure that the stopper 65 reliably contacts both the fixing member 70 and the outer member 13, it may be defined as "same" if the thickness of the stopper 65 in the unloaded state is 0 to +1 mm relative to dimension W.

[0080] This dimensional relationship allows the stopper 65 to be sandwiched between the fixing member 70 and the outer member 13 with almost no compressive deformation of the stopper 65. As a result, when the bolt 76 is fitted into the screw hole 63 of the mounting projection 62, it is difficult to generate a reaction force due to the compressive deformation of the stopper 65, and the work of attaching the fixing member 70 to the mounting projection 62 is made easier.

[0081] The lower surface 73 of the fixing member 70 curves toward the center in the left-right direction, along the outer circumferential surface of the outer member 13. The dimension W between this curved lower surface 73 and the outer circumferential surface of the outer member 13 is formed to be substantially constant over the circumferential direction. This ensures that when the stopper 65 is sandwiched between the lower surface 73 and the outer circumferential surface of the outer member 13, the contact area between them is secured. As a result, the movement of the stopper 65 in response to vehicle vibrations and other factors can be further suppressed, and the generation of abnormal noises caused by that movement can be further suppressed.

[0082] Furthermore, the entire fixing member 70, including the curved lower surface 73, is formed symmetrically. Therefore, even if the fixing member 70 is attached to the outer member 13 with its left and right sides reversed, the stopper 65 can still be placed between the lower surface 73 and the outer circumferential surface of the outer member 13. This eliminates the need to check the left-right orientation of the fixing member 70 when attaching it to the outer member 13, thus simplifying the installation process.

[0083] Although the present invention has been described above based on embodiments, it is easy to infer that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention. For example, the shapes, dimensions, and materials of the vibration isolation devices 11, 41, 61, stoppers 30, 65, fixing members 50, 70, and bracket 2 are examples, and it is natural that various shapes, dimensions, and materials can be used.

[0084] For example, the inner member 12 may be formed in a cylindrical shape, or it may be formed in a columnar or prismatic shape. In this specification, cylindrical and columnar shapes are collectively referred to as axial shapes. Depending on the shape of the inner member 12, the method of fixing the inner member 12 to the bracket 2 can be appropriately changed. In addition, the cylindrical portion 15 of the outer member 13 may be omitted, and the vibration-damping base 14 may be directly connected to the inner circumferential surface of the cylindrical thickness portion 16.

[0085] The connection between the inner member 12 and the outer member 13 is not limited to four points in the circumferential direction by the vibration-damping base 14; it may also be connected at three or fewer points, or five or more points. Furthermore, the connection between the inner member 12 and the outer member 13 may be extended around the entire circumference by the vibration-damping base 14.

[0086] In the above embodiment, the case in which the inner member 12 is fixed to the power unit side via the bracket 2 and the outer member 13 is fixed to the vehicle body side was described, but it is not necessarily limited to this. The inner member 12 may be fixed to the vehicle body side via the bracket 2 and the outer member 13 may be fixed to the power unit side.

[0087] In the above embodiment, a case was described in which the first mounting portion 18 or mounting projection 62 is provided on the upper side of the outer member 13 and the second mounting portion 19 is provided on the lower left side of the outer member 13, but this is not necessarily the only case. For example, these positions may be reversed. Specifically, the first mounting portion 18 or mounting projection 62 may be provided on the lower left side of the outer member 13 and the second mounting portion 19 may be provided on the upper side of the outer member 13. Accordingly, the positions and shapes of the various parts of the stoppers 30 and 65 may be changed.

[0088] In the second and third embodiments described above, the fixing members 50 and 70 were described as mass members for adjusting the resonant frequency of the outer member 13, but the invention is not necessarily limited to this. The fixing members 50 and 70 may also be composed of stays that connect the outer member 13 to the vehicle body, or stays for attaching harnesses (various wiring).

[0089] In the third embodiment described above, the case in which the fixing member 70 is formed symmetrically was explained, but it is not necessarily limited to this, and it may be asymmetrical. For example, the lower surface 73 of the fixing member 70 may be curved along the outer circumferential surface of the outer member 13 over its entire length in the left-right direction. This allows for a wider contact area between the lower surface 73 and the outer member 13 when the stopper 65 is sandwiched between them. As a result, the movement of the stopper 65 in response to vehicle vibrations can be further suppressed, and the generation of abnormal noises caused by that movement can be further suppressed.

[0090] In the second embodiment described above, the case in which the vicinity of the mounting hole 38 of the stopper 30 is sandwiched between the fixing member 50 and the outer member 13 was explained, but the invention is not necessarily limited to this. For example, the dimensions may be adjusted so that the stopper 30 is not sandwiched between the fixing member 50 and the outer member 13.

[0091] In the above embodiment, the case in which the stoppers 30 and 65 are provided with a circumferential portion 36 and an axial extension portion 37 has been described, but it is not necessarily limited to this. These may be omitted from the stoppers 30 and 65, and a mounting hole 38 may be formed through the circumferential portion 31. Furthermore, the circumferential portion 36, the axial extension portion 37, the mounting hole 38, the second mounting portion 19, and the overhang portion 20 (or fixing member 50) may be omitted. That is, only one side A1 of the stoppers 30 and 65 may be attached to the outer member 13. [Explanation of Symbols]

[0092] 10, 40, 60 Vibration Isolation Unit 12 Inner members 13 Outer member 14 Vibration Isolation Base 18. First mounting section 18a Through hole 19 2nd Collection and Payment Department 20 sheets 30,65 ストッパ 31-week facial 32 End face 33 circumference end 33a Page 1 33b Page 2 33c has a bottom acupoint 33d bottom 34 elastic protrusions 35 Stop the convex part 35a end face 36 Zhou Yanbu 37 Shaft Extension 38 Take and pay points 62 Take and pay convex part 66 insertion point 70 Fixed parts A1 One side A2 Other side

Claims

1. A shaft-shaped inner member, A cylindrical outer member surrounding the inner member, An elastic vibration-damping base connecting the outer circumferential surface of the inner member and the inner circumferential surface of the outer member, The system includes an elastic stopper attached to the outer member, The outer member is provided with a plate-shaped first mounting portion that rises from the outer peripheral surface of the outer member, The first mounting portion has a through hole formed through it in the thickness direction of the plate. The stopper has a circumferential surface portion that covers a part of the outer surface of the outer member in the circumferential direction, A circumferential end portion provided on one side of the circumferential surface portion, An elastic projection protruding from the peripheral end and inserted into the through hole, A vibration isolation unit characterized by comprising: a retaining projection extending along the first mounting portion from the tip of the elastic projection that protrudes from the first mounting portion toward one side in the circumferential direction beyond the first mounting portion through the through hole; and a retaining projection.

2. A mounting hole is formed through the other side of the stopper in the circumferential direction. The outer member includes a second mounting portion that protrudes from the outer peripheral surface of the outer member and is inserted into the mounting hole, The vibration isolation unit according to claim 1, further comprising an overhang extending from the tip of the second mounting portion toward the other side in the circumferential direction.

3. A shaft-shaped inner member, A cylindrical outer member surrounding the inner member, An elastic vibration-damping base connecting the outer circumferential surface of the inner member and the inner circumferential surface of the outer member, The outer member comprises an elastic stopper attached to the outer member, having a circumferential surface portion that covers a part of the outer surface of the outer member in the circumferential direction, The stopper has a through hole formed through one side in the circumferential direction and a mounting hole formed through the other side in the circumferential direction. The outer member has a mounting projection that protrudes from the outer peripheral surface of the outer member and is inserted into the through hole, A second mounting portion protrudes from the outer peripheral surface of the outer member and is inserted into the mounting hole, The second mounting portion comprises an overhang extending from the tip of the mounting portion toward the other side in the circumferential direction, A vibration damping unit characterized in that a fixing member is attached to the tip of the mounting projection, the fixing member being larger than the insertion hole, thereby fixing the stopper to the outer member.

4. The stopper has a pair of circumferential extensions that extend from the circumferential surface portion to the other side in the circumferential direction and are spaced apart from each other in the axial direction of the outer member, It comprises a pair of axial extensions that are spanned across each of the pair of circumferential extensions and are separated from each other in the circumferential direction, The vibration isolation unit according to claim 2 or 3, characterized in that the portion surrounded by the pair of circumferential portions and the pair of axial portions is the mounting hole.

5. The peripheral end portion has a first surface from which the elastic projection protrudes, A second surface opposite to the first surface, The vibration isolation unit according to claim 1 or 2, characterized in that the bottom of the bottomed hole opening to the second surface is located inside the elastic projection.

6. The vibration isolation unit according to claim 5, characterized in that the bottom is located on the tip side of the elastic projection rather than the end face on the peripheral end side of the retaining projection.

7. The vibration isolation unit according to any one of claims 1 to 3, characterized in that the stopper comprises a pair of end faces that protrude radially inward from the axial edges of the circumferential surface so as to cover a portion of both axial ends of the outer member.

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