Vibration isolation device

Abstract

To provide a vibration isolation device that can prevent the vibration-damping bush from falling off the bracket. [Solution] The stopper 5 comprises an insertion portion 50 that is inserted into the small-diameter hole 44 of the second bracket 4, and a claw portion 51 that protrudes outward from one end of the insertion portion 50 in the axial direction O. By inserting the insertion portion 50 into the small-diameter hole 44 and hooking the claw portion 51 onto the stepped surface 46, the stopper 5 can be attached to the second bracket 4. In this attached state of the stopper 5, the stopper portion 52 provided on the other end of the insertion portion 50 in the axial direction O protrudes outward from the outer surface 42 of the press-fit portion 41, so that the misalignment of the second bracket 4 and the inner cylinder 31 in the axial direction O can be restricted by the stopper portion 52. Therefore, the detachment of the vibration-damping bush 3 (inner cylinder 31) from the second bracket 4 can be suppressed.

Description

Technical Field

[0001] The present invention relates to a vibration isolation device, and particularly to a vibration isolation device capable of suppressing the detachment of a vibration isolation bush from a bracket.

Background Art

[0002] For example, Patent Document 1 describes a vibration isolation device in which a vibration isolation bush 32 is interposed between a bracket 14 (first bracket) fixed to an engine 10 and a cylindrical female screw member 40 (second bracket) fixed to an electric compressor 12. The vibration isolation bush 32 is attached to an attachment hole 35 formed in the bracket 14.

[0003] The vibration isolation bush 32 includes a cylindrical outer cylinder fitting 36 press-fitted into the attachment hole 35, a cylindrical inner cylinder fitting 34 disposed on the inner peripheral side of the outer cylinder fitting 36, and a rubber elastic body 38 connecting the outer cylinder fitting 36 and the inner cylinder fitting 34. The large-diameter portion 42 of the cylindrical female screw member 40 is press-fitted into the inner peripheral side of the inner cylinder fitting 34, whereby the cylindrical female screw member 40 is elastically supported by the bracket 14 via the vibration isolation bush 32.

[0004] A small-diameter portion 44 having a diameter smaller than that of the large-diameter portion 42 is formed on the tip side of the large-diameter portion 42 of the cylindrical female screw member 40, and a first flange portion 46 having a diameter larger than that of the large-diameter portion 42 is formed on the base end side of the large-diameter portion 42. When the large-diameter portion 42 is press-fitted into the inner cylinder fitting 34, it is inserted into the inner peripheral side of the inner cylinder fitting 34 from the small-diameter portion 44 side of the cylindrical female screw member 40, and the large-diameter portion 42 is press-fitted until the inner cylinder fitting 34 and the first flange portion 46 come into contact with each other.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the conventional technology described above, when the cylindrical female thread member 40 is molded by casting or other means, a draft angle for mold removal is sometimes provided on the outer surface of the large-diameter portion 42. This draft angle causes the outer diameter of the large-diameter portion 42 to gradually decrease from the first flange portion 46 side to the small-diameter portion 44 side. When such a draft angle is provided, vibrations input from the electric compressor 12 side (or engine 10 side) make it easier for the inner cylinder fitting 34 to come off towards the tip side (small-diameter portion 44 side) of the large-diameter portion 42. Therefore, there was a problem that the vibration-damping bush 32 was prone to falling off the cylindrical female thread member 40 (bracket).

[0007] This invention was made to solve the above-mentioned problems and aims to provide a vibration isolation device that can suppress the detachment of vibration isolation bushings from brackets. [Means for solving the problem]

[0008] To achieve this objective, the vibration isolation device of the present invention comprises: a first bracket attached to either the vibration receiving side or the vibration source side; a vibration isolation bush attached to the first bracket; a second bracket elastically supported by the vibration isolation bush and attached to the other side of the vibration receiving side or the vibration source side; and a stopper that restricts axial displacement of the second bracket and the vibration isolation bush. The vibration isolation bush comprises: a cylindrical outer cylinder press-fitted into a press-fit hole formed in the first bracket; a cylindrical inner cylinder disposed on the inner circumference side of the outer cylinder; and an elastic body connecting the inner cylinder and the outer cylinder. The second bracket is press-fitted into the inner circumference side of the inner cylinder and the vibration isolation bush. The second bracket has a press-fit portion in which the outer diameter is gradually reduced from one side to the other in the axial direction, and the second bracket has a large-diameter hole extending from one end to the other end in the axial direction of the press-fit portion, a small-diameter hole connected to the other end in the axial direction of the large-diameter hole and opening to the other end face of the press-fit portion with an inner diameter smaller than that of the large-diameter hole, and a stepped surface that radially connects the inner surface of the small-diameter hole and the large-diameter hole, and the stopper has an insertion portion that is inserted into the small-diameter hole, a claw portion that protrudes outward from one end in the axial direction of the insertion portion and hooks onto the stepped surface, and a stopper portion that protrudes outward from the other end in the axial direction of the insertion portion beyond the outer surface of the press-fit portion and restricts axial misalignment between the second bracket and the inner cylinder. [Effects of the Invention]

[0009] The vibration isolation device described in claim 1 provides the following effects. The second bracket of the vibration isolation device has a large-diameter hole extending from one axial end to the other end of the press-fit portion, a small-diameter hole connected to the other axial end of the large-diameter hole and opening to the other axial end face of the press-fit portion with an inner diameter smaller than that of the large-diameter hole, and a stepped surface connecting the inner circumferential surfaces of the small-diameter hole and the large-diameter hole in the radial direction. The stopper has an insertion portion that is inserted into the small-diameter hole of the second bracket and a claw portion that protrudes outward from one axial end of the insertion portion. The stopper is attached to the second bracket by inserting the insertion portion into the small-diameter hole and hooking the claw portion onto the stepped surface.

[0010] In this stopper mounting configuration, the stopper portion located on the other axial end of the insertion portion protrudes further outward than the outer circumferential surface of the press-fit portion. This allows the stopper portion to restrict axial misalignment between the second bracket and the inner cylinder. Therefore, it has the effect of preventing the vibration-damping bush from falling out of the second bracket.

[0011] The vibration isolation device according to claim 2 provides the following effects in addition to the effects of the vibration isolation device according to claim 1. The vibration isolation bush is provided on the other axial end side of the inner cylinder and has a first contact portion that protrudes axially from the press-fit portion and contacts the stopper portion, so that a gap can be formed between the axial end face of the press-fit portion and the stopper portion. By forming this gap, contact between the press-fit portion and the stopper portion can be prevented, which has the effect of suppressing the generation of abnormal noise associated with such contact.

[0012] The vibration isolation device described in claim 3 has the effect of suppressing the generation of abnormal noise associated with contact between the first contact portion and the stopper portion, in addition to the effects of the vibration isolation device described in claim 2. The first contact portion is an elastic body that covers the end face on the other axial side of the inner cylinder. Furthermore, the elastic force of the first contact portion, which is made of an elastic body, pushes the stopper portion to the other axial side, thereby pressing the claw portion of the stopper against the stepped surface of the second bracket. This suppresses rattling of the claw portion against the stepped surface. Therefore, it also has the effect of suppressing the generation of abnormal noise associated with contact between the stepped surface and the claw portion.

[0013] The vibration isolation device according to claim 4 provides the following effects in addition to the effects of the vibration isolation device according to claim 3. A support surface is formed on one axial end of the outer surface of the press-fit portion, which protrudes outward from the inner cylinder, and a second contact portion is provided on one axial end of the inner cylinder, which contacts the support surface of the press-fit portion. In the axial direction, the distance from the end face of the second contact portion to the end face of the first contact portion is greater than the distance from the support surface to the end face of the press-fit portion. Therefore, when press-fitting the press-fit portion of the second bracket into the inner circumference of the inner cylinder, by press-fitting the press-fit portion until the second contact portion contacts the support surface of the second bracket, a state can be formed in which the first contact portion protrudes outward from the press-fit portion on the other axial side. As a result, the above-mentioned protruding state of the first contact portion can be formed without adjusting the amount of press-fitting of the press-fit portion into the inner cylinder, which has the effect of improving the workability of the assembly work of the vibration isolation device.

[0014] According to the vibration isolation device of claim 5, in addition to the effects of the vibration isolation device of claim 4, the second contact portion is an elastic body that covers the end face on one side of the inner cylinder in the axial direction, so that the generation of abnormal noise associated with contact between the second contact portion and the support surface can be suppressed. Furthermore, since the first and second contact portions, which are made of elastic bodies, are provided on both the axial end faces of the inner cylinder, even if the orientation of the inner cylinder in the axial direction is reversed, each of the first and second contact portions can be brought into contact with the stopper portion of the stopper and the support surface of the second bracket. As a result, when pressing the vibration isolation bush (outer cylinder) into the first bracket, it is no longer necessary to consider the orientation of the vibration isolation bush, which has the effect of improving the workability of the assembly work of the vibration isolation device.

[0015] The vibration isolation device described in claim 6, in addition to the effects of the vibration isolation device described in claim 1, has the advantage that the claw portion is press-fitted into the small-diameter hole, eliminating the need to adjust the relative position of the claw portion with respect to the small-diameter hole when inserting the insertion portion into the small-diameter hole. Therefore, it has the advantage of improving the workability of the stopper installation work.

[0016] The vibration isolation device described in claim 7, in addition to the effects of the vibration isolation device described in claim 6, has a through-hole formed in the stopper that penetrates in the axial direction. Therefore, when the claw portion is pressed into the small-diameter hole, the insertion portion is more easily elastically deformed toward the through-hole. As a result, the claw portion can be easily pressed into the small-diameter hole, which improves the workability of the stopper installation process.

[0017] The vibration isolation device according to claim 8 provides the following effects in addition to those of the vibration isolation device according to claim 7. Since the insertion portion and claw portion are formed in multiple locations spaced apart in the circumferential direction, the insertion portion is more elastically deformed toward the through-hole when the claw portion is press-fitted into the small-diameter hole, compared to the case where each of these portions is formed continuously in the circumferential direction. Therefore, the claw portion can be press-fitted into the small-diameter hole more easily, which has the effect of improving the workability of the stopper installation work.

[0018] The vibration isolation device according to claim 9 provides the following effects in addition to the effects of the vibration isolation device according to claim 1. Multiple claws are formed at intervals in the circumferential direction, and notches are formed on the inner circumferential surface of the small-diameter hole at positions into which each of the multiple claws can be inserted. By rotating the claw inserted through the notch, the claw can be hooked onto the stepped surface, so even if the protrusion dimension of the claw from the insertion part is made long, the claw can be easily hooked onto the stepped surface. Making the protrusion dimension of the claw from the insertion part long has the effect of making it difficult for the stopper to fall out of the small-diameter hole.

[0019] According to the vibration isolation device of claim 10, in addition to the effects of the vibration isolation device of claim 9, the vibration isolation bush is made of an elastic body that covers the end face on the other axial side of the inner cylinder and has a first contact portion that protrudes axially from the press-fit portion and contacts the stopper portion. Therefore, when vibration is input to the vibration isolation device, the rotation of the stopper can be suppressed by friction between the first contact portion and the stopper portion. This prevents the claw portion from coming out of the notch (the claw portion from rotating to the position of the notch), and thus has the effect of preventing the stopper from falling out of the small diameter hole.

[0020] According to the vibration isolation device described in claim 11, in addition to the effect achieved by the vibration isolation device described in claim 10, the vibration isolation bush is formed on the axial end face of the first contact portion and includes a plurality of protruding portions arranged in the circumferential direction. Therefore, when vibration is input to the vibration isolation device, the rotation of the stopper can be effectively suppressed by the friction between the protruding portions and the stopper portion. Thus, there is an effect that the dropout of the stopper from the small-diameter hole can be suppressed.

[0021] According to the vibration isolation device described in claim 12, in addition to the effect achieved by the vibration isolation device described in claim 10, a recess is formed in the stepped surface at a position where a plurality of claw portions can be fitted. Therefore, when vibration is input to the vibration isolation device, the rotation of the stopper can be effectively suppressed by the engagement between the claw portions and the recess. Thus, there is an effect that the dropout of the stopper from the small-diameter hole can be suppressed.

Brief Description of the Drawings

[0022] [Figure 1] (a) is a front view of the vibration isolation device of the first embodiment, and (b) is a cross-sectional view of the vibration isolation device taken along line Ib-Ib of FIG. 1(a). [Figure 2] It is a cross-sectional view of the vibration isolation device showing the state in which the stopper is attached to the small-diameter hole of the second bracket from the state of FIG. 1(b). [Figure 3] (a) is a cross-sectional view of the vibration isolation device showing the state in which the stopper of the modified example is attached to the small-diameter hole, (b) is a rear view of the stopper viewed in the direction of arrow IIIb in FIG. 3(a), and (c) is a side view of the stopper viewed in the direction of arrow IIIc in FIG. 3(b). [Figure 4] (a) is a front view of the vibration isolation device of the second embodiment, (b) is a rear view of the stopper, and (c) is a side view of the stopper viewed in the direction of arrow IVc in FIG. 4(b). [Figure 5] (a) is a cross-sectional view of the vibration isolation device taken along line Va-Va of FIG. 4(a), and (b) is a partially enlarged cross-sectional view of the vibration isolation device taken along line Vb-Vb of FIG. 5(a). [Figure 6] It is a front view of the vibration isolation device of the third embodiment. [Figure 7](a) is a partially enlarged cross-sectional view of the vibration isolation device along the line VIIa-VIIa in Figure 6, and (b) is a partially enlarged cross-sectional view of the vibration isolation device along the line VIIb-VIIb in Figure 7(a). [Modes for carrying out the invention]

[0023] Preferred embodiments will be described below with reference to the attached drawings. Figure 1(a) is a front view of the vibration isolation device 1 of the first embodiment, and Figure 1(b) is a cross-sectional view of the vibration isolation device 1 along the line Ib-Ib in Figure 1(a). Note that Figure 1 shows the vibration isolation device 1 in an unloaded state where no vibration (load) is input (the same applies to subsequent figures).

[0024] As shown in Figure 1, the vibration isolation device 1 is an engine mount that elastically supports the vehicle's engine. The vibration isolation device 1 comprises a first metal bracket 2 attached to the engine (vibration source) side, a vibration isolation bush 3 attached to the first bracket 2, and a second metal bracket 4 elastically connected to the first bracket 2 via the vibration isolation bush 3.

[0025] The first bracket 2 is equipped with a flat mounting portion 20 that is fastened and fixed to the engine side, and a cylindrical press-fit portion 21 is integrally formed on the mounting portion 20. The first bracket 2 has a press-fit hole 22 that penetrates along the axis O direction of the vibration damping device 1 (vibration damping bush 3), and the vibration damping bush 3 is fitted into this press-fit hole 22, which has a circular cross-section.

[0026] The vibration-damping bush 3 comprises a cylindrical outer cylinder 30 that is press-fitted into the inner circumference of the press-fit hole 22, and a cylindrical inner cylinder 31 is positioned on the inner circumference of the outer cylinder 30. Both the outer cylinder 30 and the inner cylinder 31 are made of metal.

[0027] An elastic body 32 is vulcanized and bonded to the inner circumferential surface of the outer cylinder 30 and the outer circumferential surface of the inner cylinder 31, and the outer cylinder 30 and the inner cylinder 31 are connected by this elastic body 32. The second bracket 4 is fitted to the inner circumferential side of the inner cylinder 31, so that the first bracket 2 is elastically supported by the second bracket 4 via the vibration-damping bush 3.

[0028] The second bracket 4 is equipped with a flat mounting portion 40 that is attached to the vehicle body (vibration receiving) side, and a cylindrical press-fit portion 41 extending along the axis O direction is integrally formed on the mounting portion 40. The outer circumferential surface 42 of the press-fit portion 41 (the press-fit surface that is press-fitted into the inner cylinder 31) is formed in a frustoconical shape in which the outer diameter gradually decreases from one end to the other end in the axis O direction (from the left to the right in Figure 1(b)). The tapered shape of this outer circumferential surface 42 is the draft angle when the second bracket 4 is molded by casting or the like, and the angle of the outer circumferential surface 42 with respect to the axis O is, for example, 1.5° or more and 10° or less.

[0029] The second bracket 4 has a large-diameter hole 43 with a circular cross-section that penetrates the mounting portion 40 and the press-fit portion 41 along the axis O direction, and the inner diameter of the large-diameter hole 43 is formed to gradually decrease from one end to the other end in the axis O direction (from left to right in Figure 1(b)). The tapered shape of the inner circumferential surface of this large-diameter hole 43 is also the draft angle during mold molding of the second bracket 4.

[0030] On the other end of the large-diameter hole 43 in the axial direction O (right side in Figure 1(b)), there is a series of small-diameter holes 44 for attaching the stopper 5 (see Figure 2), which will be described later. The small-diameter holes 44 are circular in cross-section holes that open into the end face 45 of the press-fit portion 41 (second bracket 4) in the axial direction O, and the inner diameter of the small-diameter holes 44 is approximately constant across both ends in the axial direction O.

[0031] When assembling the vibration isolation device 1, first the outer cylinder 30 of the vibration isolation bush 3 is press-fitted into the press-fit hole 22 of the first bracket 2, and then the press-fit portion 41 (outer surface 42) of the second bracket 4 is press-fitted into the inner circumference side of the inner cylinder 31 of the vibration isolation bush 3.

[0032] In the state before the press-fit portion 41 is pressed in, the inner diameter of the inner cylinder 31 is constant across both ends in the direction of axis O, and there is no taper like that of the outer circumferential surface 42 of the press-fit portion 41. Therefore, when the press-fit portion 41 is pressed into the inner cylinder 31, the inner cylinder 31 elastically deforms to a shape that follows the taper of the outer circumferential surface 42 of the press-fit portion 41.

[0033] The restoring force of the inner cylinder 31 due to this elastic deformation tightens the press-fit portion 41, so that the press-fit portion 41 can be firmly held on the inner circumference side of the inner cylinder 31. Therefore, compared to a case where, for example, a taper similar to that of the outer circumferential surface 42 of the press-fit portion 41 is provided on the inner cylinder 31 in advance (before the press-fit portion 41 is pressed in), it is possible to suppress the inner cylinder 31 from coming out on the other end side in the axial direction O of the press-fit portion 41 (the right side in Figure 1(b)).

[0034] However, repeated input of idle vibrations when the vehicle is stopped and large-amplitude shake vibrations when the vehicle is running (hereinafter, these vibrations are collectively referred to simply as "vibrations") can cause the inner cylinder 31 to detach from the outer circumferential surface 42 of the press-fit portion 41. In this embodiment, a stopper 5 (see Figure 2) is provided on the vibration damping device 1 to prevent the vibration damping bush 3 from falling out of the second bracket 4 in this manner.

[0035] The detailed configuration of the stopper 5 will be explained with reference to Figure 2. Figure 2 is a cross-sectional view of the vibration isolation device 1 showing the state in which the stopper 5 is attached to the small-diameter hole 44 of the second bracket 4, compared to the state in Figure 1(b).

[0036] As shown in Figure 2, the inner diameter of the small-diameter hole 44 of the second bracket 4 is smaller than the inner diameter of the other end of the large-diameter hole 43 in the direction of axis O (the right end in Figure 2), thereby forming a stepped surface 46 (see enlarged portion in Figure 2) at the boundary between the large-diameter hole 43 and the small-diameter hole 44. The stepped surface 46 is a plane that connects the inner circumferential surfaces of the large-diameter hole 43 and the small-diameter hole 44 in the radial direction (a direction perpendicular to the direction of axis O), and the stopper 5 is attached using this stepped surface 46.

[0037] The stopper 5 comprises an insertion portion 50 inserted into the small-diameter hole 44, a claw portion 51 protruding outward from one end of the insertion portion 50 in the axial direction O (the left end in Figure 2), and a disc-shaped stopper portion 52 extending outward from the other end of the insertion portion 50 in the axial direction O (the right end in Figure 2). These parts 50 to 52 constituting the stopper 5 are integrally formed using resin or metal (such as aluminum or iron).

[0038] The insertion portion 50 is formed in a solid cylindrical shape, and the claw portion 51 is continuously formed around the entire circumference of this insertion portion 50. The outer diameter of the insertion portion 50 is formed to be slightly smaller than the inner diameter of the small diameter hole 44, while the outer diameter of the claw portion 51 is formed to be larger than the inner diameter of the small diameter hole 44. The stopper 5 is attached to the second bracket 4 by the claw portion 51, which is press-fitted from the other end of the small diameter hole 44 in the axial direction O (right side in Figure 2), hooking onto the stepped surface 46 (edge ​​of the small diameter hole 44 on the other end in the axial direction O). Note that the attachment of this stopper 5 may be performed after press-fitting the press-fit portion 41 into the inner cylinder 31, or it may be performed simultaneously with press-fitting the press-fit portion 41.

[0039] On one end face of the claw portion 51 in the direction of axis O, an inclined surface 53 (see enlarged portion of Figure 2) is formed that slopes outward from one end to the other end (from left to right in Figure 2) in the direction of axis O. The inclined surface 53 is formed continuously in the circumferential direction and guides the press-fitting of the claw portion 51 into the small diameter hole 44. During this press-fitting, the claw portion 51 elastically deforms, and when the claw portion 51 exceeds the small diameter hole 44, the claw portion 51 is hooked onto the stepped surface 46.

[0040] When the stopper 5 is attached to the second bracket 4 (hereinafter referred to as "the state in which the stopper 5 is attached"), the stopper portion 52 protrudes outward from the outer peripheral surface 42 of the press-fit portion 41 (to a position facing the inner cylinder 31 in the direction of axis O), so that the stopper portion 52 can restrict the misalignment of the second bracket 4 and the inner cylinder 31 in the direction of axis O. Therefore, even if vibrations are repeatedly input to the vibration isolation device 1, it is possible to suppress the vibration isolation bush 3 (inner cylinder 31) from falling out of the second bracket 4 (press-fit portion 41).

[0041] Furthermore, when the stopper 5 is installed, a gap S (see enlarged portion in Figure 2) is formed between the end face 45 of the second bracket 4 (press-fit portion 41) and the stopper portion 52 to prevent contact between them. This configuration will be explained below.

[0042] The elastic body 32 of the vibration-damping bush 3 comprises a connecting portion 32a that connects the outer cylinder 30 and the inner cylinder 31 in the radial direction, covering portions 32b and 32c that are connected to the connecting portion 32a and cover the end faces on both sides of the inner cylinder 31 in the axial direction O, and a covering portion 32d (see enlarged portion in Figure 2) that connects the covering portions 32b and 32c in the axial direction O and covers the inner circumferential surface of the inner cylinder 31. Each of these portions 32a to 32d is integrally formed from rubber or thermoplastic elastomer, but some of them may be formed separately.

[0043] The covering portion 32b covers the end face of the inner cylinder 31 on one side in the axial direction O (left side in Figure 2), and the covering portion 32c covers the end face of the inner cylinder 31 on the other side in the axial direction O (right side in Figure 2). The covering portions 32b and 32c are formed continuously in the circumferential direction, and as will be described in detail later, these covering portions 32b and 32c are the parts that are compressed between the support surface 47 of the second bracket and the stopper portion 52 of the stopper 5. Although not shown in the figures, before being compressed by the support surface 47 and the stopper portion 52, the end faces of the covering portions 32b and 32c on both sides in the axial direction O are formed in a planar shape.

[0044] The covering portion 32d is formed as a continuous film in the circumferential direction, and the entire inner circumferential surface of the inner cylinder 31 is covered by this covering portion 32d. In this embodiment, the press-fit portion 41 is press-fitted to the inner circumferential side of the covering portion 32d, but the covering portion 32d may be omitted and the press-fit portion 41 may be directly press-fitted to the inner circumferential surface of the inner cylinder 31.

[0045] A support surface 47 is formed on one end of the outer circumferential surface 42 of the press-fit portion 41 in the axial direction O (left side in Figure 2), protruding toward the outer circumferential side. This support surface 47 is formed continuously in the circumferential direction of the second bracket 4, and the covering portion 32b of the vibration-damping bush 3 is configured as a contact portion that comes into contact with the support surface 47 when the press-fit portion 41 is press-fitted into the inner cylinder 31.

[0046] The dimension L1 from the end face of the covering portion 32b on one side in the axial direction O (left side in Figure 2) to the end face of the covering portion 32c on the other side in the axial direction O (right side in Figure 2) is set to be larger than the dimension L2 from the support surface 47 of the second bracket 4 to the end face 45 of the press-fit portion 41. As a result, when the press-fit portion 41 is pressed into the inner cylinder 31 until the covering portion 32b contacts the support surface 47 of the second bracket 4, the covering portion 32c (inner cylinder 31) protrudes beyond the end face 45 of the press-fit portion 41 on the other side in the axial direction O (right side in Figure 2), and this protruding portion contacts the stopper portion 52 of the stopper 5.

[0047] In this contact state, the covering portion 32c is compressed by the stopper portion 52, and the elastic force of the covering portion 32c pushes the stopper portion 52 outwards in the direction of axis O (to the right in Figure 2). This pushing action presses the claw portion 51 against the stepped surface 46 of the second bracket 4 (see enlarged portion in Figure 2), while creating a gap S between the end face 45 of the press-fit portion 41 and the stopper portion 52. By creating such a gap S, contact between the stopper portion 52 and the end face 45 of the press-fit portion 41 (second bracket 4) can be suppressed when vibration is input to the vibration isolation device 1, thereby suppressing the generation of abnormal noise caused by such contact.

[0048] The gap S between the end face 45 of the press-fit portion 41 and the stopper portion 52 can be formed even if the support surface 47 of the second bracket 4 and the covering portions 32b and 32c of the vibration-damping bush 3 are omitted. If these are omitted, the amount of press-fitting of the press-fit portion 41 relative to the inner cylinder 31 should be adjusted so that a gap S is formed between the end face 45 of the press-fit portion 41 and the stopper portion 52 (i.e., so that the inner cylinder 31 protrudes to the side of the stopper portion 52 beyond the end face 45 of the press-fit portion 41).

[0049] However, in a configuration that omits the covering parts 32b, 32c and the support surface 47, when vibration is input to the vibration isolation device 1, there is a risk that the inner cylinder 31 may come into contact with the support surface 47 or the stopper part 52, causing abnormal noise to occur.

[0050] Furthermore, in configurations that omit the covering portions 32b, 32c and the support surface 47, adjusting the press-fit amount of the press-fit portion 41 so that the inner cylinder 31 protrudes from the end face 45 of the press-fit portion 41 is time-consuming. In addition, dimensional errors in the inner cylinder 31 and stopper 5 (insertion portion 50) in the axial O direction, and errors in the press-fit amount of the press-fit portion 41, can make it difficult to properly form the gap S between the end face 45 of the press-fit portion 41 and the stopper portion 52. Moreover, even if the gap S can be formed, if there is a gap between the stepped surface 46 and the claw portion 51, rattling of the stopper 5 can easily cause abnormal noise due to contact between the stopper portion 52 and the inner cylinder 31, or between the claw portion 51 and the stepped surface 46.

[0051] In contrast, in this embodiment, the end face of the inner cylinder 31 on the other side in the axial direction O (right side in Figure 2) is covered by an elastic covering portion 32c, which suppresses the generation of abnormal noise due to contact between the inner cylinder 31 and the stopper portion 52. Furthermore, by covering the end face of the inner cylinder 31 in the axial direction O with the covering portion 32c, the elastic force of the covering portion 32c pushes the stopper portion 52 to the other side in the axial direction O, allowing the claw portion 51 to press against the stepped surface 46, thus suppressing rattling of the claw portion 51 against the stepped surface 46. Therefore, the generation of abnormal noise due to contact between the stepped surface 46 and the claw portion 51 can also be suppressed.

[0052] Furthermore, even if dimensional errors occur in the inner cylinder 31 or stopper 5 (insertion portion 50) in the axial direction O, or errors in the amount of press-fitting of the press-fit portion 41 into the inner cylinder 31, these errors can be absorbed by the covering portion 32c. In other words, even if such errors occur, the elastic force of the covering portion 32c makes it easier for the claw portion 51 to be pressed against the stepped surface 46, thereby suppressing rattling of the stopper 5 and reliably forming the gap S between the second bracket 4 and the stopper portion 52. Thus, it is possible to suppress the generation of abnormal noise due to contact between the stopper portion 52 and the inner cylinder 31, or contact between the claw portion 51 and the stepped surface 46.

[0053] Furthermore, in this embodiment, the support surface 47 that the covering portion 32b contacts is formed on the outer circumferential surface 42 of the press-fit portion 41, and the axial dimension L1 of the inner cylinder 31 including the covering portions 32b and 32c in the O direction is made larger than the dimension L2 of the outer circumferential surface 42 of the press-fit portion 41 in the same direction. With this configuration, simply by press-fitting the press-fit portion 41 into the inner cylinder 31 until the covering portion 32b contacts the support surface 47, a state in which the covering portion 32c protrudes from the end face 45 of the press-fit portion 41 (i.e., a state in which a gap S is formed) can be easily created. Therefore, it is not necessary to adjust the amount of press-fitting of the press-fit portion 41 into the inner cylinder 31 in order to form a gap S between the end face 45 of the press-fit portion 41 and the stopper portion 52, thus improving the workability of the assembly work of the vibration isolation device 1.

[0054] Furthermore, since both end faces of the inner cylinder 31 in the axial direction O are covered by the covering portions 32b and 32c, it is unnecessary to consider the direction of press-fitting when pressing the vibration-damping bush 3 (outer cylinder 30) into the first bracket 2. In other words, even if the orientation of the vibration-damping bush 3 (inner cylinder 31) in the axial direction O is reversed from the state shown in Figure 2, the covering portions 32b and 32c can still be brought into contact with the support surface 47 and the stopper portion 52. Thus, the workability of assembling the vibration-damping device 1 can be improved.

[0055] In the second embodiment described later (see Figure 4), when the claw portion 251 of the stopper 205 is inserted through a notch 244a formed in the small-diameter hole 44, it is necessary to assemble the stopper 205 while adjusting the relative position between the notch 244a and the claw portion 251. On the other hand, in this embodiment, since the claw portion 51 of the stopper 5 is press-fitted into the small-diameter hole 44, it is not necessary to adjust the relative position of the claw portion 51 with respect to the small-diameter hole 44 (the position of the claw portion 51 in the circumferential direction) when inserting the insertion portion 50 into the small-diameter hole 44. Therefore, the workability of the installation work of the stopper 5 can be improved.

[0056] Next, a modified example of the stopper 5 will be described with reference to Figure 3, but the same reference numerals will be used for parts identical to those in the first embodiment described above, and their descriptions will be omitted. Figure 3(a) is a cross-sectional view of the vibration isolation device 1 showing the modified stopper 5 attached to the small-diameter hole 44, Figure 3(b) is a rear view of the stopper 5 in the direction of arrow IIIb in Figure 3(a), and Figure 3(c) is a side view of the stopper 5 in the direction of arrow IIIc in Figure 3(b).

[0057] As shown in Figure 3, the modified stopper 5 has a through hole 54 with a circular cross-section that penetrates in the direction of axis O. In addition, the insertion portion 50 and the claw portion 51 are formed in multiple locations (four locations in this embodiment) at equal intervals in the circumferential direction. With these configurations, compared to the case where the entire stopper 5 (insertion portion 50 and claw portion 51) is formed solid as in the first embodiment described above, the insertion portion 50 is more easily elastically deformed toward the through hole 54 side (inner circumference side) when the claw portion 51 is pressed into the small diameter hole 44. Therefore, even if the protruding length of the claw portion 51 toward the outer circumference side (the engagement amount of the claw portion 51 with respect to the stepped surface 46) is formed to be relatively long, the press-fitting of the claw portion 51 into the small diameter hole 44 can be easily performed. Thus, the workability of the assembly work of the stopper 5 can be improved.

[0058] On the other hand, when the claw portion 51 passes through the small-diameter hole 44, the insertion portion 50 returns to its original shape, allowing the relatively long claw portion 51 to hook onto the stepped surface 46 (the edge of the small-diameter hole 44). Therefore, even if vibrations are repeatedly input to the vibration isolation device 1, the stopper 5 can be prevented from falling out of the small-diameter hole 44, and the press-fit state of the second bracket 4 to the inner cylinder 31 can be reliably maintained by the stopper portion 52.

[0059] Next, the vibration isolation device 201 of the second embodiment will be described with reference to Figures 4 and 5. Note that the same reference numerals are used for parts identical to those in the first embodiment described above, and their descriptions are omitted. Figure 4(a) is a front view of the vibration isolation device 201 of the second embodiment, Figure 4(b) is a rear view of the stopper 205, and Figure 4(c) is a side view of the stopper 205 in the direction of arrow IVc in Figure 4(b).

[0060] Figure 5(a) is a cross-sectional view of the vibration isolation device 201 along the line Va-Va in Figure 4(a), and Figure 5(b) is a partially enlarged cross-sectional view of the vibration isolation device 201 along the line Vb-Vb in Figure 5(a). In Figure 5(b), the inner circumferential surface of the small-diameter hole 44 hidden by the claw portion 251 of the stopper 205 is shown with a dashed line, and only the press-fit portion 41 (second bracket 204) and the stopper 205 are shown to simplify the drawing.

[0061] As shown in Figures 4 and 5, the second bracket 204 in the vibration isolation device 201 of the second embodiment has the same configuration as the second bracket 4 of the first embodiment, except that a notch 244a is formed on the inner circumferential surface of the small-diameter hole 44.

[0062] The notch 244a is a fan-shaped cutout in a portion of the inner circumferential surface of the small-diameter hole 44 when viewed in the direction of axis O. The notches 244a are formed in pairs at symmetrical positions on either side of axis O, and the claw portion 251 of the stopper 205 is inserted through this pair of notches 244a.

[0063] The stopper 205 of this second embodiment is equipped with an insertion portion 50 and a stopper portion 52 similar to the stopper 5 of the first embodiment, and a claw portion 251 is integrally formed on the outer circumferential surface of the insertion portion 50. In addition, a convex portion 255 is integrally formed on the outer circumferential surface of the stopper portion 52. The claw portions 251 are formed in pairs at positions symmetrical with respect to the axis O (positions corresponding to the pair of notches 244a), and each of these pair of claw portions 251 is formed in a fan shape corresponding to the shape of the notch 244a.

[0064] The dimensions of the claw portion 251 in the circumferential direction are formed to be slightly smaller than the dimensions (opening width) of the notch 244a in the same direction. When attaching the stopper 205 to the second bracket 204, the pair of claw portions 251 are inserted through the pair of notches 244a. After inserting the claw portions 251 into the notches 244a, the stopper 205 is rotated to hook the claw portions 251 onto the stepped surface 46 (see Figure 5). The protrusion 255 allows confirmation of whether the engagement between the stepped surface 46 and the claw portions 251 is appropriate.

[0065] The protrusions 255 are formed in pairs at symmetrical positions with respect to the axis O, and the protruding direction of this pair of protrusions 255 (left-right direction in Figure 4(b)) is configured to be perpendicular to the protruding direction of the pair of claws 251 (up-down direction in Figure 4(b)). In other words, each of the pair of protrusions 255 is formed at a position offset by 90° from the pair of claws 251 in the circumferential direction.

[0066] As a result, after inserting the claw portion 251 through the pair of notches 244a, the stopper 205 can be rotated until the pair of protrusions 255 face up and down, thereby hooking almost the entire claw portion 251 onto the stepped surface 46 (to the state shown in Figure 5(b)). In other words, the claw portion 251 can be properly hooked onto the stepped surface 46 without visually checking the state of the claw portion 251's engagement with the stepped surface 46.

[0067] In the mounting state of the stopper 205 (as shown in Figure 5(a)), similar to the first embodiment, the stopper portion 52 protrudes outward from the outer peripheral surface 42 of the press-fit portion 41, so that the stopper portion 52 can restrict the misalignment of the second bracket 204 and the inner cylinder 31 in the axial direction O. Therefore, even if vibrations are repeatedly input to the vibration isolation device 201, the stopper 205 can prevent the vibration isolation bush 3 (inner cylinder 31) from falling out of the second bracket 204 (press-fit portion 41).

[0068] Thus, in this embodiment, the claw portion 251 inserted through the notch 244a is rotated to hook onto the stepped surface 46 without utilizing the elastic deformation of the claw portion 251 or the insertion portion 50. With this configuration, even if the length of the claw portion 251 facing the outer circumference (the amount of engagement of the claw portion 251 with respect to the stepped surface 46) is formed to be relatively long, the claw portion 251 can be easily hooked onto the stepped surface 46. By hooking the relatively long claw portion 251 onto the stepped surface 46, the stopper 205 can be reliably prevented from falling out of the small diameter hole 44.

[0069] Furthermore, in this embodiment as well, since the elastic covering portion 32c is pressed against the stopper portion 52, when vibration is input to the vibration isolation device 201, the rotation of the stopper 205 due to that vibration can be restricted by friction between the covering portion 32c and the stopper portion 52. By restricting the rotation of the stopper 205, it is possible to prevent the claw portion 251 from coming out of the notch 244a (the claw portion 251 from rotating to the position of the notch 244a), thereby preventing the stopper 205 from falling out of the small diameter hole 44.

[0070] Next, the vibration isolation device 301 of the third embodiment will be described with reference to Figures 6 and 7, but the same reference numerals are used for parts that are the same as those in the embodiments described above, and their descriptions will be omitted. Figure 6 is a front view of the vibration isolation device 301 of the third embodiment.

[0071] Figure 7(a) is a partially enlarged cross-sectional view of the vibration isolation device 301 along the line VIIa-VIIa in Figure 6, and Figure 7(b) is a partially enlarged cross-sectional view of the vibration isolation device 301 along the line VIIb-VIIb in Figure 7(a). In Figure 7(b), the inner circumferential surface of the small-diameter hole 44 hidden by the claw portion 251 of the stopper 205 is shown with a dashed line, and only the press-fit portion 41 (second bracket 304) and the stopper 205 are shown to simplify the drawing.

[0072] As shown in Figures 6 and 7, the second bracket 304 of the vibration isolation device 301 of the third embodiment has recesses 346a formed in the stepped surface 46 (see Figure 7) for fitting the claw portion 251. The recesses 346a are recesses formed along the inner edge of the stepped surface 46 (in the region including the inner edge of the stepped surface 46) and are formed in a fan shape when viewed in the direction of axis O. The recesses 346a are formed in pairs at symmetrical positions with respect to axis O, and after inserting the claw portion 251 through the notch 244a, the stopper 205 is rotated 90° to fit the claw portion 251 into each of the pair of recesses 346a.

[0073] When the claw portion 251 is fitted into the recess 346a, the rotation of the stopper 205 is restricted by the circumferential engagement between the edge (side wall) of the recess 346a and the claw portion 251. In this embodiment as well, the covering portion 32c (projection portion 332e, described later) of the elastic body 332 is pressed against the stopper portion 52. The elastic force of this covering portion 32c acts in a direction that pushes the claw portion 251 into the recess 346a, so even when vibration is input to the vibration isolation device 301, the state in which the claw portion 251 is fitted into the recess 346a is easily maintained. Therefore, the rotation of the stopper 205 can be effectively suppressed.

[0074] Furthermore, the elastic body 332 of this embodiment has a plurality of protrusions 332e (see Figure 6) formed on the end face of the covering portion 32c in the direction of axis O. The protrusions 332e are projections that extend from the covering portion 32c to the other side in the direction of axis O (towards the foreground in the direction perpendicular to the plane of the paper in Figure 6). The protrusions 332e are formed in a fan shape, with their width dimension in the circumferential direction gradually increasing from the inner circumference to the outer circumference, and a plurality of (eight in this embodiment) protrusions 332e are formed arranged at equal intervals in the circumferential direction.

[0075] By forming multiple protrusions 332e (see Figure 6) on the covering portion 32c, the rotation of the stopper 205 can be effectively suppressed by friction between the covering portion 32c (protrusions 332e) and the stopper portion 52, compared to, for example, a case where the end face of the covering portion 32c in the axial direction O is flat. By suppressing the rotation of the stopper 205, even when vibrations are repeatedly input to the vibration isolation device 301, the claw portion 251 cannot be prevented from coming out of the notch 244a. Therefore, the detachment of the stopper 205 from the small diameter hole 44 can be suppressed.

[0076] Although the present invention has been described above based on the above embodiments, it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various modifications and improvements are possible without departing from the spirit of the present invention.

[0077] Parts of each of the above embodiments may be replaced with parts of other embodiments, and parts of each of the above embodiments may be added to other embodiments. As an example of such a configuration, a configuration is given in which the projection 332e of the third embodiment is formed on the covering portion 32c of the first and second embodiments.

[0078] In the embodiments described above, elastic covering portions 32b and 32c were used as examples of contact portions (first contact portions) that contact the stopper portion 52 of the stopper 5,205 and contact portions (second contact portions) that contact the support surface 47 of the second bracket 4,204,304, but the invention is not limited to these. For example, one or both of the covering portions 32b and 32c may be omitted, and the axial end face of the inner cylinder 31 may be in direct contact with the stopper portion 52 or the support surface 47 (in this configuration, the axial end face of the inner cylinder 31 corresponds to the first and second contact portions).

[0079] In the embodiments described above, the cases in which the connecting portion 32a and the covering portions 32b and 32c of the elastic bodies 32 and 332 are formed in a continuous manner (where each of these portions 32a to 32c is formed integrally) have been explained. However, one or both of the covering portions 32b and 32c may be formed separately from the connecting portion 32a.

[0080] In the embodiments described above, the dimension L1 from the end face of the covering portion 32b on one side in the axial direction O to the end face of the first contact portion on the other side in the axial direction O is described as being larger than the dimension L2 from the support surface 47 to the end face 45 of the press-fit portion 41 on the other side in the axial direction O. However, the invention is not limited to this. For example, the dimensions L1 and L2 may be the same, or the dimension L2 may be larger than the dimension L1. It is also not necessary to form a gap S between the end face 45 of the press-fit portion 41 and the stopper portion 52.

[0081] In the embodiments described above, the cases in which the small-diameter holes 44 of the second brackets 4,204,304 and the insertion portions 50 of the stoppers 5,205 have the same circular cross-sectional shape were explained, but this is not necessarily the case. For example, the cross-sectional shapes of the small-diameter holes 44 and the insertion portions 50 may be polygonal, or the small-diameter holes 44 and the insertion portions 50 may have different cross-sectional shapes.

[0082] In the embodiments described above, the stopper portion 52 is formed in a disc shape, that is, the portion that restricts the detachment of the inner cylinder 31 (vibration-damping bush 3) is formed continuously in the circumferential direction of the stopper 5. However, the invention is not limited to this. For example, the shape of the stopper portion 52 may be polygonal, or the stopper portion 52 may be formed intermittently in the circumferential direction. In other words, the shape of the stopper portion 52 can be changed as appropriate, as long as the configuration can restrict the detachment of the inner cylinder 31 (vibration-damping bush 3) from the press-fit portion 41 (second bracket 4, 204, 304).

[0083] In the third embodiment described above, a case was described in which a projection 332e is formed on the covering portion 32c and a recess 346a is formed on the stepped surface 46. However, either the projection 332e or the recess 346a may be omitted. [Explanation of Symbols]

[0084] 1,201,301 Vibration Isolator 2. First bracket 22 Press-fit hole 3. Vibration-damping bushings 30 Outer cylinder 31 Inner cylinder 32,332 elastic bodies 32b Covering portion (second contact portion) 32c Covered portion (first contact portion) 332e Projection (1st contact part) 4,204,304 Second bracket 41 Press-fit section 43 Large diameter holes 44 Small diameter hole 244a Notch 46 Step surface 346a Recess 47 Support surface 5,205 Stopper 50 Insertion part 51,251 Nail portion 52 Stopper section O-axis S Gap

Claims

1. The system comprises a first bracket attached to either the vibration receiving side or the vibration source side, a vibration-damping bush attached to the first bracket, a second bracket elastically supported by the vibration-damping bush and attached to the other side of the vibration receiving side or the vibration source side, and a stopper that restricts axial displacement of the second bracket and the vibration-damping bush. The vibration-damping bush comprises a cylindrical outer cylinder that is press-fitted into a press-fit hole formed in the first bracket, a cylindrical inner cylinder positioned on the inner circumference side of the outer cylinder, and an elastic body connecting the inner cylinder and the outer cylinder. The second bracket is press-fitted into the inner circumference of the inner cylinder and has a press-fit portion in which the outer diameter is gradually reduced from one axial side to the other side of the vibration-damping bush. The second bracket is formed with a large-diameter hole extending from one axial end to the other end of the press-fit portion, a small-diameter hole connected to the other axial end of the large-diameter hole and opening to the other axial end face of the press-fit portion with a smaller inner diameter than the large-diameter hole, and a stepped surface connecting the inner circumferential surfaces of the small-diameter hole and the large-diameter hole in the radial direction. The vibration isolation device is characterized by comprising: an insertion portion inserted into the small-diameter hole; a claw portion protruding outward from one axial end of the insertion portion and hooking onto the stepped surface; and a stopper portion protruding outward from the other axial end of the insertion portion beyond the outer surface of the press-fit portion and restricting axial misalignment between the second bracket and the inner cylinder.

2. The vibration-damping bush is provided on the other axial end side of the inner cylinder and has a first contact portion that protrudes axially in the other direction from the press-fit portion and contacts the stopper portion. The vibration isolation device according to claim 1, characterized in that a gap is formed between the end face on the other axial side of the press-fit portion and the stopper portion.

3. The vibration isolation device according to claim 2, characterized in that the first contact portion is an elastic body that covers the end face on the other axial side of the inner cylinder.

4. A support surface is formed on one axial end of the outer surface of the press-fit portion, which protrudes outward from the inner cylinder. A second contact portion is provided at one axial end of the inner cylinder, which contacts the support surface. The vibration isolation device according to claim 3, characterized in that, in the axial direction, the dimension from the end face of the second contact portion to the end face of the first contact portion is greater than the dimension from the support surface to the end face of the press-fit portion.

5. The vibration isolation device according to claim 4, characterized in that the second contact portion is an elastic body that covers the end face on one axial side of the inner cylinder.

6. The vibration isolation device according to claim 1, characterized in that the claw portion is press-fitted into the small-diameter hole.

7. The vibration isolation device according to claim 6, characterized in that the stopper has a through hole that penetrates in the axial direction.

8. The vibration isolation device according to claim 7, characterized in that the insertion portion and the claw portion are formed in multiple locations spaced apart in the circumferential direction.

9. Multiple claw portions are formed at intervals in the circumferential direction. Notches are formed on the inner circumferential surface of the small-diameter hole at positions into which each of the multiple claw portions can be inserted. The vibration isolation device according to claim 1, characterized in that the claw portion inserted through the notch is rotated to hook onto the stepped surface.

10. The vibration damping bush is made of an elastic body that covers the end face of the inner cylinder on the other axial side, and is provided with a first contact portion that protrudes axially from the press-fit portion and contacts the stopper portion, as described in claim 9.

11. The vibration isolation device according to claim 10, characterized in that the vibration isolation bush is formed on the axial end face of the first contact portion and comprises a plurality of projections arranged in the circumferential direction.

12. The vibration isolation device according to claim 10, characterized in that recesses are formed in the stepped surface at positions into which a plurality of the claw portions can be fitted.

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