Vibration-damping rubber

Abstract

To provide vibration-damping rubber that effectively absorbs vibrations in a specific direction. [Solution] A vibration-damping rubber comprising a cylindrical collar member having an insertion hole, a rubber member having a fitting hole formed therein and fitted to the outer circumference of the collar member, and an outer member fitted to the outer circumference of the rubber member, wherein the collar member alternately has a plurality of collar protrusions that project outward when viewed from the axial direction of the insertion hole and a plurality of collar recesses formed between the collar protrusions around the axis of the insertion hole, the rubber member has rubber recesses and rubber protrusions formed on the inner surface of the fitting hole, the rubber member fits tightly to the outer circumference of the collar member by fitting the collar protrusions and the rubber recesses and the collar recesses and rubber protrusions together, and a slit is formed on the outer circumference side of the rubber recess in the rubber member.

Description

Technical Field

[0001] The present disclosure relates to an anti-vibration rubber. Background Art

[0002] Conventionally, a structure is known in which a drive motor for an electric vehicle or the like is attached to a chassis via a mounting member. The drive motor vibrates due to vibration generated by rotation of the motor and vibration transmitted from wheels. In order to absorb this vibration, a rubber bush is used for the mounting member. A rubber bush is generally a substantially cylindrical rubber member that plays a role in absorbing vibration and reducing vibration transmitted to the chassis (Patent Document 1). Prior Art Documents Patent Documents

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. 2020-131931 Summary of the Invention Problems to be Solved by the Invention

[0004] The drive motor may vibrate particularly in the front-rear direction due to vibration transmitted from wheels. However, since a conventional rubber bush has a substantially cylindrical shape, it has not been able to sufficiently absorb vibration of the drive motor in the front-rear direction. As a result, vibration of the drive motor is transmitted to the chassis, which may adversely affect ride comfort due to vibration, noise, and the like.

[0005] The present disclosure has been made in view of the above problems of the prior art, and an object of the present disclosure is to provide an anti-vibration rubber that effectively absorbs vibration in a specific direction. Means for Solving the Problems

[0006] The vibration-damping rubber of this disclosure comprises a cylindrical collar member having an insertion hole, a rubber member having a fitting hole and fitted to the outer circumference of the collar member, and an outer member fitted to the outer circumference of the rubber member, wherein the collar member alternately has a plurality of collar protrusions projecting outward when viewed from the axial direction of the insertion hole and a plurality of collar recesses formed between the collar protrusions around the axis of the insertion hole, the rubber member has rubber recesses and rubber protrusions formed on the inner surface of the fitting hole, the rubber member fits tightly to the outer circumference of the collar member by fitting the collar protrusions and the rubber recesses and the collar recesses and rubber protrusions together, and a slit is formed on the outer circumference side of the rubber recess in the rubber member. [Effects of the Invention]

[0007] According to the vibration-damping rubber of this disclosure, vibrations can be effectively absorbed by the deformation of the slits in the rubber member. In particular, since the ease of deformation of the rubber (elastic modulus) in the direction of the collar recess and rubber protrusion as viewed from the through hole is different from the elastic modulus of the rubber in the direction of the collar protrusion and rubber recess, vibrations in a specific direction can be effectively absorbed by appropriately designing the mounting direction of the vibration-damping rubber. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram shows the mounting structure of the drive motor. [Figure 2] This is a perspective view of the front motor with vibration-damping rubber applied. [Figure 3] This is a side view of a front motor with vibration-damping rubber applied. [Figure 4] This is a perspective view of the rear motor with vibration-damping rubber applied. [Figure 5] This is a side view of the rear motor with vibration-damping rubber applied. [Figure 6] This is a detailed diagram of the vibration-damping rubber. [Figure 7] This is a magnified view of a part of the vibration-damping rubber. [Figure 8] This is a cross-sectional view of a motor mounting structure with vibration-damping rubber applied. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. The embodiments described below are all specific examples of this disclosure. Therefore, the components, their arrangement and connection configurations shown in the following embodiments are examples only and are not intended to limit this disclosure.

[0010] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. In each figure, substantially identical components are given the same reference numerals, and redundant explanations may be omitted or simplified. Also, in the XYZ coordinate axes in the figures, the +X direction indicates the front of the vehicle, the +Y direction indicates the right side of the vehicle, and the +Z direction indicates the vertically upward direction of the vehicle.

[0011] Figure 1 shows a schematic diagram of a structure in which a drive motor is mounted to a chassis using the vibration-damping rubber of this disclosure. The chassis 7 has a pair of left and right side frames 711 and right side frames 712 extending in the longitudinal direction of the vehicle, and a first cross member 72, a second cross member 74 and a third cross member 75 provided in the vehicle width direction between the left side frame 711 and the right side frame 712, and is configured as a ladder shape overall. The ends of the first cross member 72, the second cross member 74 and the third cross member 75 are fixed to the left side frame 711 and the right side frame 712.

[0012] Furthermore, the left side frame 711 and the right side frame 712 are provided with left mounting portion 731 and right mounting portion 732, respectively, which protrude inward in the vehicle width direction for attaching the front motor 101. The front motor 101 is fixed to the first cross member 72 via the front bracket 8-1, to the left mounting portion 731 via the left rear bracket 8-2, and to the right mounting portion 732 via the right rear bracket 8-3.

[0013] The output shaft of the front motor 101 is connected to the left front drive shaft 111 and the right front drive shaft 112 via a transmission mechanism, and the left front wheel 91 and the right front wheel 92 are connected to the left front drive shaft 111 and the right front drive shaft 112, respectively. The left front wheel 91 and the right front wheel 92 are drive wheels that are rotationally driven by the driving force of the front motor 101. The left front drive shaft 111 and the right front drive shaft 112 are each slightly inclined so as they move outward in the vehicle width direction, they move forward towards the vehicle.

[0014] The rear motor 102 is fixed to the second cross member 74 via the left front bracket 8-4 and the right front bracket 8-5, and to the third cross member 75 via the rear bracket 8-6.

[0015] The output shaft of the rear motor 102 is connected to the left rear drive shaft 121 and the right rear drive shaft 122 via a transmission mechanism, and the left rear wheel 93 and the right rear wheel 94 are connected to the left rear drive shaft 121 and the right rear drive shaft 122, respectively. The left rear wheel 93 and the right rear wheel 94 are drive wheels that are rotationally driven by the driving force of the rear motor 102. The left rear drive shaft 121 and the right rear drive shaft 122 are each slightly inclined so as they move outward in the vehicle width direction, they move towards the rear of the vehicle.

[0016] Figure 2 is a rearward perspective view of the front motor 101 from the upper left, and Figure 3 is a left side view of the front motor 101. A front bracket 8-1 is attached to the front of the front motor 101 approximately in the center. A left rear bracket 8-2 and a right rear bracket 8-3 are attached to the rear of the front motor 101 on the left and right sides, respectively. Insertion holes 81-1, 81-2, and 81-3 are formed in the front bracket 8-1, left rear bracket 8-2, and right rear bracket 8-3, respectively, and vibration-damping rubber 1 is fitted into each of these insertion holes 81-1, 81-2, and 81-3.

[0017] The vibration-proof rubber 1 of the front bracket 8-1 is fastened to the first cross member 72 by a bolt 5 and a nut 6. Further, the vibration-proof rubber 1 of the left rear bracket 8-2 is fastened to the left mounting portion 731, and the vibration-proof rubber 1 of the right rear bracket 8-3 is fastened to the right mounting portion 732, respectively by bolts 5 and nuts 6. All of the vibration-proof rubbers 1 are mounted such that their central axes are oriented in the left-right direction of the vehicle.

[0018] Fig. 4 is an upper left front perspective view of the rear motor 102, and Fig. 5 is a left side view of the rear motor 102. A left front bracket 8-4 and a right front bracket 8-5 are respectively attached to the left and right of a front portion of the rear motor 102. Further, a rear bracket 8-6 is attached at a substantially central rear portion of the rear motor 102. Insertion holes 81-4 and 81-5 are respectively formed in the left front bracket 8-4 and the right front bracket 8-5, and the vibration-proof rubber 1 is fitted into each of the insertion holes 81-4 and 81-5.

[0019] A rear mount bracket 8-7 is connected to the rear bracket 8-6 via the vibration-proof rubber 1. The rear mount bracket 8-7 is a bracket fastened to a third cross member 75. An insertion hole 81-7 is formed in the rear mount bracket 8-7, and the vibration-proof rubber 1 is fitted into the insertion hole 81-7. Then, the bolt 5 is inserted through an insertion hole formed in the rear bracket 8-6 and the vibration-proof rubber 1, and the nut 6 is screwed onto the bolt 5, whereby the rear bracket 8-6 and the rear mount bracket 8-7 are connected via the vibration-proof rubber 1.

[0020] The vibration-proof rubber 1 of the left front bracket 8-4 and the vibration-proof rubber 1 of the right front bracket 8-5 are respectively fastened to a second cross member 74 by bolts 5 and nuts 6. Further, the rear bracket 8-6 is fastened to a third cross member 75 via the vibration-proof rubber 1 and the rear mount bracket 8-7. All of the vibration-proof rubbers 1 are mounted such that their central axes are oriented in the left-right direction of the vehicle.

[0021] Figure 6 shows a detailed view of the vibration-damping rubber 1, and Figure 7 is a magnified view of a part thereof. Figure 7 shows the upper left portion of the vibration-damping rubber 1 shown in Figure 6, but since the structure of the vibration-damping rubber 1 is symmetrical around its central axis, the upper right, lower left, and lower right portions have substantially the same structure. Figure 8 is a cross-sectional view along line AA in Figure 5. Line A'-A' in Figure 6 corresponds to line AA in Figure 5. Figure 8 shows the structure for attaching the left front bracket 8-4 to the second cross member 74, but the structure for attaching the front bracket 8-1 to the first cross member 72, the structure for attaching the left rear bracket 8-2 to the left mounting part 731, the structure for attaching the right rear bracket 8-3 to the right mounting part 732, and the structure for attaching the left front bracket 8-4 and right front bracket 8-5 to the second cross member 74 are all substantially the same, so the structure shown in Figure 8 can also be applied to the mounting structures of the other brackets.

[0022] The vibration-damping rubber 1 comprises a collar member 2, a rubber member 3, and an outer member 4. The collar member 2 has a through hole 21 through which mounting bolts 5 are inserted, and is made of metal or resin. The outer surface of the collar member 2 has a plurality (four in this embodiment) of collar protrusions 22-1, 22-2, 22-3, and 22-4 that project outward radially when viewed from the axial direction of the through hole 21, and collar recesses 23-1, 23-2, 23-3, and 23-4 formed between adjacent collar protrusions 22-1, 22-2, 22-3, and 22-4. The collar protrusions 22-1, 22-2, 22-3, and 22-4 and the collar recesses 23-1, 23-2, 23-3, and 23-4 are arranged alternately at equal intervals around the axis of the through hole 21. In this embodiment, four colored protrusions 22-1, 22-2, 22-3, and 22-4 are formed around the insertion hole 21 at equal intervals of 90 degrees.

[0023] The rubber member 3 is a rubber member fitted to the outside of the collar member 2. A fitting hole 31 is formed in the center of the rubber member 3, and the collar member 2 is fitted inside it. The fitting hole 31 has rubber recesses 32-1, 32-2, 32-3, and 32-4 corresponding to the collar protrusions 22-1, 22-2, 22-3, and 22-4, and rubber protrusions 33-1, 33-2, 33-3, and 33-4 corresponding to the collar recesses 23-1, 23-2, 23-3, and 23-4 formed on its inner surface so that the collar member 2 fits tightly inside it.

[0024] Slits 34-1, 34-2, 34-3, and 34-4 are formed on the outer circumference of the rubber recesses 32-1, 32-2, 32-3, and 32-4, penetrating in the direction of the central axis of the vibration-damping rubber 1 (perpendicular to the plane of the paper in Figure 6). Since the slits 34-1, 34-2, 34-3, and 34-4 are all the same shape, slit 34-1 will be described in detail according to Figure 7. Slit 34-1 has a central portion 34-1-1 that is circumferentially flattened when viewed from the central axis of the vibration-damping rubber 1, and ends 34-1-2 formed at both ends of the central portion 34-1-1, which are thicker than the central portion 34-1-1 and slightly offset in the outer circumference. With respect to slit 34-1, a stopper portion 35-1 is formed on the opposite side from the collar protrusion 22-1 and the rubber recess 32-1. The stopper portion 35-1 is formed to protrude inward from the outer circumference of the slit 34-1, and faces the opposing wall portion 34-1-3 on the inside of the slit 34-1 with a gap g1 between them.

[0025] Furthermore, as shown in Figure 8, the outer periphery of the slits 34-1, 34-2, 34-3, and 34-4 of the rubber member 3 has protrusions 36-1, 36-2, 36-3, and 36-4 that project in the direction of the central axis of the vibration-damping rubber 1 (in Figure 8, protrusion 36-4 is indicated with the reference numerals 36-4-1 and 36-4-2). Therefore, the length of the rubber member 3 in the direction of the central axis is longer in the outer periphery of the slits 34-1, 34-2, 34-3, and 34-4 than in the other parts.

[0026] A roughly cylindrical outer member 4 is fitted around the outer circumference of the rubber member 3. The outer member 4 is made of resin or metal and serves to protect the vibration-damping rubber from wear and tear.

[0027] The vibration-damping rubber 1 is inserted into the insertion holes 81-1, 81-2, 81-3, 81-4, 81-5, and 81-7 of the brackets 8-1, 8-2, 8-3, 8-4, 8-5, and 8-7 for attaching the front motor 101 and rear motor 102 to the chassis 7. Figure 8 shows how the vibration-damping rubber 1 inserted into the insertion hole 81-4 of the left front bracket 8-4 of the rear motor 102 is fastened to the mounting portions 76, 76 formed on the second cross member 74. The rear motor 102 is positioned so that the mounting hole 77 and the through hole 21 formed on the mounting portion 76 are in a roughly straight line, and the bolt 5 is inserted through the mounting hole 77 and the through hole 21. Then, the rear motor 102 is attached to the mounting portion 76 of the chassis 7 by screwing a nut 6 onto the bolt 5 and tightening it. In this case, the length of the color member 2 is slightly shorter than the distance between the mounting parts 76, 76, and therefore the vibration-damping rubber 1 is fitted between the mounting parts 76, 76. The protruding part 36 faces the mounting parts 76, 76 with a small gap g2 between them.

[0028] Next, we will explain how the vibration-damping rubber 1 of this embodiment absorbs vibrations during driving of a vehicle in which the motor is mounted on the chassis. When vibrations caused by the rotation of the motor, vibrations input to the motor from the road surface through the wheels and drive shaft, etc. act on the motor and chassis, the motor and chassis move relative to each other due to the vibrations.

[0029] When the motor vibrates relative to the chassis, the bracket attached to the motor also vibrates along with the motor. When the bracket vibrates, the outer member 4 of the vibration-damping rubber 1, which is fitted into the insertion hole of the bracket, also vibrates. In contrast, the collar member 2, which is fastened to the chassis 7 by bolts 5 and nuts 6, hardly vibrates relative to the chassis 7. Therefore, the collar member 2 and the outer member 4 vibrate relatively.

[0030] The following explanation assumes that the outer member 4 vibrates relative to the collar member 2, but the same applies when the collar member 2 vibrates relative to the outer member 4. When the collar member 2 and the outer member 4 vibrate, the rubber member 3 located between the collar member 2 and the outer member 4 deforms. Since the rubber member 3 has slits 34 formed in it, some of the slits 34 will be crushed as it deforms. For example, in Figure 6, when the outer member 4 vibrates horizontally (left-right in Figure 6) relative to the collar member 2, the outer member 4 repeatedly moves to the right so that slits 34-1 and 34-2 are crushed, and then moves to the left so that slits 34-3 and 34-4 are crushed.

[0031] As the outer member 4 moves to the right, the rubber member 3 undergoes elastic deformation such that the rubber protrusion 33-1 on the left side of the collar member 2 is compressed, the rubber protrusion 33-3 on the right side of the collar member 2 is stretched, and the upper rubber protrusion 33-4 and lower rubber protrusion 33-2 of the collar member 2 undergo elastic deformation due to shear force. When the amplitude is large, the slits 34-1 and 34-2 are crushed, and the stopper parts 35-1 and 35-2 come into contact with the opposing wall parts 34-1-3 and 34-2-3, preventing further movement. Therefore, the maximum amplitude is restricted to g1÷cos45° until the stopper parts 35-1 and 35-2 come into contact with the opposing wall parts 34-1-3 and 34-2-3.

[0032] Furthermore, when the outer member 4 moves to the left, the rubber member 3 undergoes elastic deformation such that the rubber protrusion 33-3 on the right side of the collar member 2 is compressed, the rubber protrusion 33-1 on the left side of the collar member 2 is stretched, and the upper rubber protrusion 33-4 and lower rubber protrusion 33-2 of the collar member 2 undergo elastic deformation due to shear force. When the amplitude is large, the slits 34-3 and 34-4 are crushed, and the stopper parts 35-3 and 35-4 come into contact with the opposing wall parts 34-3-3 and 34-4-3, preventing further movement. Therefore, the maximum amplitude is restricted to g1÷cos45° until the stopper parts 35-3 and 35-4 come into contact with the opposing wall parts 34-3-3 and 34-4-3.

[0033] Next, we will explain the case where the outer member 4 vibrates in a 45-degree angle direction connecting the upper left and lower right in Figure 6 relative to the collar member 2. When the outer member 4 moves to the lower right, the rubber member 3 elastically deforms so that the left rubber protrusion 33-1 and the upper rubber protrusion 33-4 of the collar member 2 are compressed and sheared in the lower right direction, while the lower rubber protrusion 33-2 and the right rubber protrusion 33-3 of the collar member 2 elastically deform so that they are stretched and sheared in the lower right direction. When the amplitude is large, the slit 34-1 collapses and the stopper portion 35-1 comes into contact with the opposing wall portion 34-1-3 and does not move any further. Therefore, the maximum amplitude is restricted to g1 until the stopper portion 35-1 comes into contact with the opposing wall portion 34-1-3.

[0034] Furthermore, when the outer member 4 moves to the upper left, the rubber member 3 elastically deforms so that the right rubber protrusion 33-3 and the lower rubber protrusion 33-2 of the collar member 2 are compressed and sheared in the upper left direction, while the upper rubber protrusion 33-4 and the left rubber protrusion 33-1 of the collar member 2 elastically deform so that they are stretched and sheared in the upper left direction. When the amplitude is large, the slit 34-3 collapses and the stopper portion 35-3 comes into contact with the opposing wall portion 34-3-3 and does not move any further. Therefore, the maximum amplitude is restricted to g1 until the stopper portion 35-3 comes into contact with the opposing wall portion 34-3-3.

[0035] As described above, the deformation of the rubber member 3 differs depending on whether the color member 2 vibrates in the left-right direction or in the upper-left-lower-right direction as shown in Figure 6. Therefore, the ease of deformation (elastic modulus) of the rubber member 3 differs in each case. In other words, when the rubber member 3 vibrates in the direction of opposing rubber protrusions, such as in the left-right or up-down direction as shown in Figure 6, it is less prone to deformation than when it vibrates in the direction of opposing slits, such as in the upper-left-lower-right or upper-right-lower-left direction. Consequently, vibrations can be appropriately absorbed by appropriately setting the orientation of the vibration-damping rubber 1.

[0036] As shown in Figure 1, if the left front drive shaft 111 and the right front drive shaft 112 are installed with respect to the front motor 101 at a slight inclination so that they are directed forward of the vehicle as they extend outward in the vehicle width direction, then vibrations transmitted axially from the left front drive shaft 111 and the right front drive shaft 112 are combined to easily cause vibrations in the vehicle longitudinal direction in the front motor 101. Similarly, if the left rear drive shaft 121 and the right rear drive shaft 122 are installed with respect to the rear motor 102 at a slight inclination so that they are directed rearward of the vehicle as they extend outward in the vehicle width direction, then vibrations transmitted axially from the left rear drive shaft 121 and the right rear drive shaft 122 are combined to easily cause vibrations in the vehicle longitudinal direction in the rear motor 102. Therefore, by installing the vibration-damping rubber 1 so that the collar recess faces the vehicle longitudinal direction, it becomes easier to absorb vibrations in the vehicle longitudinal direction.

[0037] Next, we will explain the case where the outer member 4 vibrates in the left-right direction relative to the collar member 2 in Figure 8, that is, the case where it vibrates in the direction of the central axis of the vibration-damping rubber 1. When the outer member 4 moves by g2 to the left in the figure, the protruding portion 36-4-1 of the rubber member 3 comes into contact with the left mounting portion 76, restricting further movement of the outer member 4. Similarly, when the outer member 4 moves by g2 to the right, the protruding portion 36-4-2 of the rubber member 3 comes into contact with the right mounting portion 76, restricting further movement of the outer member 4. Therefore, the maximum amplitude is restricted to g2 until the protruding portions 36-4-1 and 36-4-2 come into contact with the mounting portion 76. In this way, vibrations can be appropriately absorbed by preventing the amplitude from becoming excessive even with respect to vibrations in the axial direction (left-right direction in Figure 8) of the vibration-damping rubber 1.

[0038] The embodiments described above have been illustrated with an example of applying the vibration-damping rubber of this disclosure to a mounting structure for attaching a drive motor to a chassis. However, the applications of the vibration-damping rubber are not limited to mounting structures, and it can be applied to various vibration-damping structures, such as mounting structures for equipment that generates vibrations. Furthermore, in the above embodiments, four collar protrusions and four collar recesses are formed at equal intervals around the insertion hole, but the number of collar protrusions and collar recesses is not limited to this and may be appropriately changed depending on the vibration-damping structure to which it is applied. In addition, the protrusion height of the stopper can be appropriately designed according to the allowable amplitude, etc. Furthermore, the orientation of the collar protrusions as viewed from the axial direction of the insertion hole can be appropriately designed according to the direction and magnitude of the vibrations generated, etc. [Industrial applicability]

[0039] It can be suitably applied to vibration-damping structures such as the mounting structure of drive motors. [Explanation of Symbols]

[0040] 1. Vibration-damping rubber 2 Color components 21 Through hole 3. Rubber component 31 Fitting hole 4. Outer member 5 volts 6 nuts 7 Chassis 8 brackets 9 wheels 101 Front Motor 102 Rear Motor

Claims

1. A cylindrical collar member having an insertion hole, A fitting hole is formed in the rubber member which is fitted onto the outer circumference of the collar member, An outer member fitted to the outer circumference of the aforementioned rubber member, Vibration-damping rubber having, The aforementioned collar member has, alternately around the axis of the insertion hole, a plurality of collar protrusions that project outward when viewed from the axial direction of the insertion hole, and a plurality of collar recesses formed between the collar protrusions. The rubber member has a rubber recess and a rubber protrusion formed on the inner surface of the fitting hole, and the color protrusion and the rubber recess fit together, and the color recess and the rubber protrusion fit together, so that the rubber member fits tightly to the outer circumference of the color member, and a slit is formed on the outer circumference side of the rubber recess in the rubber member. Vibration-damping rubber.

2. A protruding portion is formed on the outer circumference of the slit in the rubber member, projecting in the direction of the central axis. The vibration-damping rubber according to claim 1.

3. A stopper portion is formed on the inner surface of the slit, protruding inward from the outer circumference and facing the collar protrusion. The vibration-damping rubber according to claim 1.

4. The aforementioned collar protrusions and collar recesses are formed in equal intervals in groups of four around the insertion hole. The vibration-damping rubber according to claim 1.

5. Vehicle body structural members, A drive motor having an insertion hole, The vibration-damping rubber according to claim 4, which is inserted into the insertion hole and attached, A fastening member that is inserted through the aforementioned insertion hole and fastens the vibration-damping rubber to the vehicle body structural member, A vehicle that possesses the following characteristics.

6. The aforementioned drive motor has a bracket, The aforementioned insertion hole is formed in the bracket. The vehicle according to claim 5.

7. A drive shaft connected to the output shaft of the aforementioned drive motor, The wheel connected to the aforementioned drive shaft, It further possesses, The drive shaft is installed so as to be inclined in the vehicle's longitudinal direction as it extends outward in the vehicle's width direction. The vehicle according to claim 5.

8. The vibration-damping rubber is mounted such that the collar protrusion is tilted 45 degrees with respect to the horizontal when viewed from the axial direction of the insertion hole. The vehicle according to claim 7.

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