Vibration damping bushings

Abstract

To provide a vibration-damping bush that can efficiently adjust vibration damping characteristics. [Solution] The vibration-damping bush 50 comprises an outer cylinder 55, an inner cylinder 56 provided inside the outer cylinder 55, rubber 57 provided to fill the space between the outer cylinder 55 and the inner cylinder 56, a bulging cylinder 65 provided midway along the central axis O direction of the inner cylinder 56 and having a shape that bulges radially outward of the inner cylinder 56, bolts 58 and nuts 59 that apply compressive force to both ends of the inner cylinder 56 in the central axis O direction when fastening the inner cylinder 56 to the bracket 40, and a spacer 60 inserted between the inner cylinder 56 and the bolts 58 along the central axis O direction of the inner cylinder 56. The spacer 60 is in contact with the bolts 58 and nuts 59 at both ends, thereby defining the compressive force that the bolts 58 and nuts 59 apply to the inner cylinder 56, and the bulging cylinder 65 deforms radially outward by an amount of deformation corresponding to the pressing force applied to the inner cylinder 56, pressing the rubber 57.

Description

Technical Field

[0001] The present invention relates to a vibration isolator bush in which an outer cylinder and an inner cylinder are connected by an elastic body such as rubber.

Background Art

[0002] Generally, vibration isolator bushes are used for connecting each arm or the like in a vehicle suspension device or the like. The vibration isolation characteristics (rigidity) of such vibration isolator bushes need to be individually adjusted according to the load input to each connection part.

[0003] As a technique for adjusting the characteristics of a vibration isolator bush, for example, the technique disclosed in Patent Document 1 is known. Patent Document 1 discloses a technique in which a vibration isolator bush is divided along a central axis into an intermediate bush and a pair of end bushes. In the technique of Patent Document 1, it is possible to prepare in advance a plurality of types of end bushes having different dimensions, formulations, etc., and select the optimum end bush when the vibration isolation performance is determined and assemble the vibration isolator bush.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique of Patent Document 1 described above, in order to adjust the vibration isolation characteristics, it is necessary to prepare in advance a plurality of types of end bushes. Therefore, there is a possibility that it may be difficult to efficiently adjust the vibration isolation characteristics in the technique of Patent Document 1.

[0006] An object of the present invention is to provide a vibration isolator bush capable of efficiently adjusting vibration isolation characteristics.

Means for Solving the Problems

[0007] A vibration-damping bush according to one aspect of the present invention comprises an outer cylinder, an inner cylinder provided inside the outer cylinder, an elastic body provided to fill the space between the outer cylinder and the inner cylinder, a bulging cylinder provided midway along the central axis of the inner cylinder and having a shape that bulges radially outward from the inner cylinder, a fastener that fastens the inner cylinder and a bracket and, when fastened, applies a compressive force to both ends of the inner cylinder in the central axis direction of the inner cylinder, and a spacer inserted between the inner cylinder and the fastener along the central axis direction of the inner cylinder, wherein the spacer is shorter than the length of the inner cylinder in the central axis direction and defines the compressive force when the fastener contacts both ends of the spacer, and the bulging cylinder deforms radially outward by an amount of deformation corresponding to the compressive force applied to the inner cylinder, pressing against the elastic body. [Effects of the Invention]

[0008] According to the vibration-damping bush of the present invention, vibration damping characteristics can be efficiently adjusted. [Brief explanation of the drawing]

[0009] [Figure 1] Rear view of the suspension system [Figure 2] Perspective view showing the connection point between the lower arm and the bracket. [Figure 3] Disassembled perspective view of vibration damping bushing [Figure 4] Sectional view IV-IV in Figure 1 [Figure 5] Cross-sectional view showing the vibration-damping bush just before compressive force is applied. [Figure 6] Perspective view showing the inner cylinder [Figure 7] Exploded perspective view showing the lower arm and bushing body. [Figure 8] Cross-sectional view showing a vibration-damping bush using a spacer of a different length than that shown in Figure 4. [Figure 9] A modified example, a perspective view showing the inner cylinder. [Figure 10] Cross-sectional view showing a modified example of a vibration-damping bushing. [Figure 11]Cross-sectional view showing the vibration isolator bush before applying the fastening torque according to the modification example [Figure 12] Cross-sectional view showing the vibration isolator bush using a spacer having a length different from that in FIG. 10 according to the modification example

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 8 relate to one embodiment of the present invention, and FIG. 1 is a rear view of a suspension device.

[0011] The suspension device 1 shown in FIG. 1 is a high-mount double wishbone type suspension device.

[0012] As shown in FIG. 1, the suspension device 1 includes a housing (knuckle) 5, a wheel hub unit 6, a lower arm 7, an upper arm 8, a hydraulic damper 9, and a suspension spring 10.

[0013] The housing 5 includes a housing body 15 and a connecting arm 16.

[0014] The housing body 15 has a bearing insertion hole 20. Further, the housing body 15 has a first ball joint mounting hole and a second ball joint mounting hole (both not shown).

[0015] The bearing insertion hole 20 is formed by a cylindrical hole penetrating the housing body 15 in the vehicle width direction.

[0016] The first ball joint mounting hole is formed by a hole penetrating the housing body 15 in the vertical direction at the lower end of the housing body 15.

[0017] The second ball joint mounting hole is provided, for example, in a protrusion 23 protruding rearward from the lower part of the housing body 15. This second ball joint mounting hole is formed by a hole penetrating the protrusion 23 in the vertical direction.

[0018] The connecting arm 16 extends from the upper part of the housing body 15 to a position reaching above the tire 101. This connecting arm 16 has a mounting hole 25 at its tip.

[0019] The wheel hub unit 6 has a bearing 30 and a wheel hub 31.

[0020] The bearing 30 is fixed to the housing body 15 in a state of being inserted through the bearing insertion hole 20.

[0021] The wheel hub 31 is rotatably supported by the housing body 15 via the bearing 30. This wheel hub 31 has a shaft support cylinder 35 and a flange 36.

[0022] The shaft support cylinder 35 has a substantially cylindrical shape. This shaft support cylinder 35 is spline-coupled to the tip of a drive shaft 37 which is an axle. Thereby, the tip of the drive shaft 37 is rotatably supported by the housing body 15 via the wheel hub unit 6.

[0023] The flange 36 is provided on the outer periphery of the shaft support cylinder 35. This flange 36 has a plurality of bolt insertion holes 36a for connecting the brake disc and the wheel of the tire 101 by fastening.

[0024] The base end portion of the lower arm 7 is swingably supported with respect to the vehicle body 100 via a bracket 40. Also, the tip end portion of the lower arm 7 is connected to a first ball joint mounting hole via a ball joint 41.

[0025] The base end portion of the upper arm p>8 is swingably supported with respect to the vehicle body 100 via a bracket 45. Also, the tip end portion of the upper arm 8 is connected to the mounting hole 25 of the connecting arm 16 via a ball joint 46.

[0026] The upper end of the hydraulic damper 9 is connected to the vehicle body 100 via a strut mount (not shown). The lower end of the hydraulic damper 9 is connected to the middle of the lower arm 7. A suspension spring 10 is held on the outer circumference of the hydraulic damper 9.

[0027] Furthermore, a tie rod 48 extending from a steering mechanism (not shown) is connected to the second ball joint mounting hole of the housing body 15 via a ball joint 49.

[0028] In such a suspension device 1, for example, the lower arm 7 and the bracket 40 are connected via a vibration-damping bush 50. The upper arm 8 and the bracket 45 are connected via a vibration-damping bush 51. Furthermore, the hydraulic damper 9 and the lower arm 7 are connected via a vibration-damping bush 52.

[0029] The connection structure between the lower arm 7 and the bracket 40 will be described in detail below. Note that the connection structure between the upper arm 8 and the bracket 45, and the connection structure between the hydraulic damper 9 and the lower arm 7 are substantially the same as the connection structure between the lower arm 7 and the bracket 40, so a detailed explanation will be omitted.

[0030] As shown in Figures 3 to 5, the vibration-damping bush 50 comprises an outer cylinder 55, an inner cylinder 56, rubber 57 as an elastic material, bolts 58 and nuts 59 as fasteners, and a spacer 60.

[0031] The outer cylinder 55 has, for example, a cylindrical shape. This outer cylinder 55 can be held at the base end of the lower arm 7, for example, as shown in Figure 7. Specifically, a bush retaining hole 7a is provided at the base end of the lower arm 7. The outer diameter of the outer cylinder 55 is set to be slightly larger than the inner diameter of the bush retaining hole 7a. This allows the outer cylinder 55 to be inserted into the bush retaining hole 7a by press-fitting. The outer cylinder 55, press-fitted into the bush retaining hole 7a, is then held at the base end of the lower arm 7.

[0032] The inner cylinder 56 has an outer diameter that is significantly smaller than the inner diameter of the outer cylinder 55. The central axis O of the inner cylinder 56 is, for example, coaxial with the central axis O of the outer cylinder 55.

[0033] As shown in Figure 6, the inner cylinder 56 has a bulge cylinder 65 midway along the central axis O. The bulge cylinder 65 is integrally formed with the inner cylinder 56. The bulge cylinder 65 has a shape that bulges radially outward from the inner cylinder 56. In this embodiment, the bulge cylinder 65 has a hollow partial spherical shape. The bulge cylinder 65 is provided with a plurality of slits 66 that extend in the direction of the central axis O of the inner cylinder 56. Each slit 66 is provided, for example, at equal intervals around the central axis O of the inner cylinder 56. These slits 66 function as deformation enhancers to promote the elastic deformation of the bulge cylinder 65 in the outer radial direction when a compressive force is applied to both ends of the inner cylinder 56 in the direction of the central axis O.

[0034] The rubber 57 is provided to fill the gap between the outer cylinder 55 and the inner cylinder 56. As a result, the outer cylinder 55, the inner cylinder 56, and the rubber 57 are integrally connected and constitute the bush body 53.

[0035] The rubber 57 undergoes a change in its standard elastic properties (rigidity) when pressure is applied. Specifically, the rubber 57's standard rigidity increases when it is pressed from the inside by the deformation of the bulging cylinder 65. More specifically, the rigidity of the rubber 57 increases as the amount of pressure applied by the deformation of the bulging cylinder 65 increases.

[0036] The bolt 58 is inserted into the interior of the inner cylinder 56, for example, from the first end side in the direction of the central axis O of the inner cylinder 56. A nut 59 is screwed onto the bolt 58 at the second end side of the inner cylinder 56. These bolts 58 and nuts 59 can compress both ends of the inner cylinder 56 by fastening. This fastening applies a compressive force to the inner cylinder 56 in the direction of the central axis O. This compressive force changes depending on the degree of fastening between the bolt 58 and the nut 59.

[0037] Here, as shown in Figure 4, the bolt 58 and nut 59 apply a compressive force to the inner cylinder 56 via the first and second backing plates 67 and 68 positioned at both ends of the inner cylinder 56. In this embodiment, the first backing plate 67 is integrally formed with the bracket 40. As a result, the bracket 40 is connected to the inner cylinder 56 (bush body 53) by fastening together with the bolt 58 and nut 59.

[0038] The spacer 60 is provided between the inner cylinder 56 and the bolt 58, along the direction of the central axis O of the inner cylinder 56. In this embodiment, the spacer 60 has a cylindrical shape.

[0039] The length of the spacer 60 in the direction of its central axis O is set to be a predetermined length shorter than the length of the inner cylinder 56 in the direction of its central axis O. Both ends of the spacer 60 in the direction of its central axis O can contact the head 58a of the bolt 58 and the nut 59, respectively, via the first and second backing plates 67 and 68, when the bolt 58 and nut 59 are fastened together. By contacting the head 58a of the bolt 58 and the nut 59, the spacer 60 can regulate the amount of fastening ΔL (see Figure 4) applied to the inner cylinder 56 by the bolt 58 and nut 59. This allows the spacer 60 to set the pressing force applied to the inner cylinder 56 by the bolt 58 and nut 59. In this embodiment, the amount of fastening ΔL refers to the distance the nut 59 is advanced toward the head 58a of the bolt 58 by further screwing of the nut 59 from the screwed position (see Figure 4) just before the bolt 58 and nut 59 apply compressive force to the inner cylinder 56. In the diagram, "L" indicates the distance between the head 58a and the nut 59 just before the bolt 58 and nut 59 apply compressive force to the inner cylinder 56.

[0040] Here, the outer diameter of the spacer 60 is set to be slightly smaller than the outer diameter of the inner cylinder 56. Also, the inner diameter of the spacer 60 is set to be slightly larger than the outer diameter of the bolt 58. This makes the spacer 60 interchangeable with respect to the inner cylinder 56 (bushing body 53). That is, for example, as shown in Figure 3, it is possible to selectively insert spacers 60 into the inner cylinder 56, each having a different length in the direction of the central axis O of the inner cylinder 56.

[0041] According to this embodiment, the vibration-damping bush 50 includes an outer cylinder 55, an inner cylinder 56 provided inside the outer cylinder 55, a rubber 57 provided to fill the space between the outer cylinder 55 and the inner cylinder 56, a bulging cylinder 65 provided midway along the central axis O direction of the inner cylinder 56 and having a shape that bulges radially outward from the inner cylinder 56, bolts 58 and nuts 59 that apply a compressive force to both ends of the inner cylinder 56 in the central axis O direction when the inner cylinder 56 is fastened to the bracket 40, and a spacer 60 inserted between the inner cylinder 56 and the bolts 58 along the central axis O direction of the inner cylinder. The spacer 60 is shorter than the length of the inner cylinder 56 in the central axis O direction, and the contact between the bolts 58 and nuts 59 at both ends of the spacer 60 defines the compressive force that the bolts 58 and nuts 59 apply to the inner cylinder. Furthermore, the bulging cylinder 65 deforms radially outward by an amount corresponding to the pressing force applied to the inner cylinder 56, thereby pressing against the rubber 57. This allows for efficient adjustment of the vibration damping characteristics of the vibration damping bush 50.

[0042] In other words, by preparing multiple spacers 60 of different lengths in advance and simply replacing the spacers 60 inserted into the inner cylinder 56, the amount of deformation of the bulging cylinder 65 can be adjusted, and the standard elastic properties (rigidity) of the rubber 57 can be changed. This rigidity of the rubber 57 contributes to the vibration damping characteristics of the vibration damping bush 50. Therefore, the vibration damping characteristics of the vibration damping bush 50 can be efficiently adjusted simply by replacing the spacers 60, which have a simple shape.

[0043] For example, as shown in Figure 8, by inserting a spacer 60 shorter than the spacer 60 shown in Figure 4 into the inner cylinder 56, the fastening amount ΔL' by the bolt 58 and nut 59 can be made larger than the fastening amount ΔL shown in Figure 4. As a result, the bolt 58 and nut 59 shown in Figure 8 apply a greater pressing force to the inner cylinder 56 than the bolt 58 and nut 59 shown in Figure 4, causing a greater deformation of the bulge cylinder 65. As a result, the amount of pressure the bulge cylinder 65 shown in Figure 8 applies to the rubber 57 increases compared to the bulge cylinder 65 shown in Figure 4, allowing the reference rigidity of the rubber 57 to be set higher.

[0044] In this case, the bulging cylinder 65 is provided with a slit 66 to facilitate its radially outward deformation. This makes it possible to accurately achieve deformation of the bulging cylinder 65 in accordance with the pressing force applied to the inner cylinder 56.

[0045] Next, a modified example of this embodiment will be described with reference to Figures 9 to 12. In this modified example, the shape of the bulging cylinder 65A differs from that of the embodiment described above.

[0046] The bulging cylinder 65A has a cylindrical portion 71 and a pair of frustoconical portions 72. The outer diameter of the cylindrical portion 71 is set to be larger than the outer diameter of the inner cylinder 56. The pair of frustoconical portions 72 are provided at both ends of the cylindrical portion 71.

[0047] Here, the bulging cylinder 65A is provided with a plurality of slits 73 extending in the direction of the central axis O of the inner cylinder 56. Each slit 73 is provided at equal intervals around the central axis O of the inner cylinder 56, for example. These slits 73 function as deformation-enhancing parts that promote the radiiating deformation of the bulging cylinder 65A in the outer diameter direction when a compressive force is applied to both ends of the inner cylinder 56 in the direction of the central axis O.

[0048] Even in these modified examples, the same effects as those of the embodiments described above are achieved.

[0049] The invention described in the above embodiments is not limited to those forms, and various modifications can be made during implementation without departing from the gist of the invention.

[0050] For example, the above-described embodiment explained an example in which vibration-damping bushes are applied to the suspension device 1, but the application of vibration-damping bushes is not limited to this. For example, they can also be applied to multi-link type suspension devices that require more vibration-damping bushes. Furthermore, the application of vibration-damping bushes is not limited to suspension devices; for example, they can also be applied to connections between mounts for mounting engines, motors, etc., and the vehicle body frame.

[0051] Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the multiple constituent elements disclosed.

[0052] For example, if the problem described can be solved and the effects described can be obtained even if some of the constituent elements shown in the above form are removed, then the configuration with the removed constituent elements can be extracted as an invention. [Explanation of Symbols]

[0053] 1. Suspension system 5… Housing (Knuckle) 5… Housing 6. Wheel hub unit 7… Lower arm 7a ... Bush retaining hole 8… Upper Arm 9. Hydraulic damper 10… Suspension springs 15… Housing body 16… Connecting arm 20 ... Bearing insertion hole 23 … Protrusion 25… Mounting holes 30… Bearings 31… Wheel hub 35… Shaft support cylinder 36… Flange 36a ... Bolt insertion hole 37… Drive shaft 40… Bracket 41… Ball joint 45… Bracket 46… Ball joint 48… Tie rod 49… Ball joint 50… Vibration damping bush 51… Vibration damping bush 52… Vibration damping bush 53… Bushing body 55… Outer cylinder 56 … Inner cylinder 57... Rubber 58... Bolts 58a ... Bolt head 59... Nut 60… Spacer 65 … Expansion tube 65A … Expansion tube 66… Slit 67... backing plate 68... backing plate 71 ... Cylindrical section 72...Truncated cone section 73… Slit 100 ... Vehicle body 101... Tires

Claims

1. Outer cylinder and An inner cylinder provided inside the outer cylinder, An elastic body is provided to fill the space between the outer cylinder and the inner cylinder, A bulging cylinder is provided midway along the central axis of the inner cylinder and has a shape that bulges radially outward from the inner cylinder, A fastener that fastens the inner cylinder and the bracket, and applies a compressive force to both ends of the inner cylinder in the direction of the central axis of the inner cylinder when fastening, A spacer is inserted between the inner cylinder and the fastener along the central axis direction of the inner cylinder, Equipped with, The spacer is shorter than the length of the inner cylinder in the central axis direction, and defines the compressive force when the fasteners abut both ends of the spacer. The vibration-damping bush is characterized in that the bulging cylinder deforms radially outward by an amount of deformation corresponding to the compressive force applied to the inner cylinder, and presses against the elastic body.

2. The vibration-damping bush according to claim 1, characterized in that the bulging cylinder has a deformation-enhancing portion for promoting the radially outward deformation of the bulging cylinder when the compressive force is applied to the inner cylinder.

3. The vibration-damping bush according to claim 1, characterized in that the spacer is replaceable relative to the inner cylinder.

4. The vibration-damping bush according to claim 1, characterized in that the bulging cylinder has a hollow, partially spherical shape.

5. The vibration-damping bush according to claim 1, characterized in that the bulging cylinder has a cylindrical portion and a pair of frustoconical cylindrical portions provided at both ends of the cylindrical portion.

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