vibration isolator

Abstract

A vibration isolation device is provided that is capable of supplying a greater current to a magnetorheological elastomer of a bushing assembly to correspondingly increase a magnetic flux density within the magnetorheological elastomer of the bushing assembly in accordance with the current supplied to the bushing assembly, and to achieve a greater change in stiffness. The vibration isolation device can be installed in a vehicle and includes a variable stiffness bushing assembly and a collar member composed of a magnetic body. The variable stiffness bushing assembly has an inner cylinder composed of a magnetic body and having a hollow shaft portion for fastening to the vehicle, an outer cylinder composed of a magnetic body and disposed coaxially with the inner cylinder on a radially outer side of the inner cylinder, a magnetorheological elastomer disposed between the inner cylinder and the outer cylinder, and a coil that applies a magnetic field that causes a change in viscoelasticity of the magnetorheological elastomer. The collar member is in contact with an axial direction end portion of the inner cylinder of the variable stiffness bushing assembly.

Description

TECHNICAL FIELD

[0001] The present application relates to a vibration isolation device, and is a vibration isolation device for mounting on a vehicle frame of a vehicle. BACKGROUND

[0002] In recent years, in all countries, safe cities and human settlements are being strengthened in order to strengthen the capacity for inclusive and sustainable urban development, sustainable human settlements planning and management in all countries. Therefore, in all countries, there is a need to strengthen the provision of safe, affordable, accessible, sustainable transport systems for all, to improve road safety, particularly by expanding public transport, with particular attention to the needs of vulnerable populations, women, children, persons with disabilities and older persons. In the field of transport, there is an urgent need to take measures to address environmental problems in order to develop technologies that can improve the convenience of public transport and traffic safety.

[0003] In the manufacturing industry of the prior art vehicle, there is a vehicle vibration isolation device (also called a vibration isolation and noise reduction device) disclosed in order to suppress the transmission of vibrations generated by a drive force distribution device supported by a sub-frame and input (vibration force) from the road to the vehicle body side. For example, in Patent Document 1, a mounting seat using a magneto-rheological elastomer is disclosed which is arranged on a sub-frame on which a drive source of a vehicle is mounted. In Patent Document 1, a technology is disclosed in which, at the time of turning in which the torque difference between the left and right wheels is large, the rigidity (yaw rigidity) of the mounting seat is increased by increasing the elastic modulus of the magneto-rheological elastomer, thereby improving the turning performance of the vehicle. In addition, in Patent Document 2, the direction of the change in rigidity caused by the magnetic field of the magneto-rheological elastomer is described.

[0004] In the prior art, a mounting seat and a magneto-rheological elastomer are provided on the sub-frame of the portion of the sub-frame of the vehicle supported by the vehicle body (main frame), so that the elastic force (resistance) applied to the mounting seat in each direction with respect to the force applied from multiple directions can be adjusted. Accordingly, in the prior art, although it is proposed that the elastic force of the mounting seat with respect to each application direction can be made variable by using a magneto-rheological elastomer, however, in the prior art, how to improve the magnetic flux density inside the magneto-rheological elastomer is not discussed.

[0005] In addition, in Patent Document 3, a fixing method of fixing a bush assembly to a vehicle frame is disclosed, in which the inner cylinder of the bush assembly is in contact with the fixed portion of the vehicle frame.

[0006] [Related Art Documents]

[0007] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent No. 6047087

[0009] [Patent Literature 2] International Publication No. 2016 / 148011

[0010] [Patent Literature 3] Japanese Patent No. 2020-133700 Publication SUMMARY

[0011] [Problems to be Solved by the Invention]

[0012] Accordingly, in the related art (Patent Literature 3 described above), in order to be able to change the elastic force of the mounting seat with respect to each of the application directions, a bush assembly provided with a magneto-rheological elastomer is mounted on the mounting seat of the vehicle frame. However, in such a fixing method, only the inner tube of the bush assembly is in contact with the fixed portion of the vehicle frame. Therefore, in the related art, since the cross-sectional area of the magnetic circuit that can be generated by the bush assembly is fixed, in the structure of such a fixed method, there is a limitation to increasing the cross-sectional area, and therefore there is also a limitation to increasing the magnetic flux density inside the magneto-rheological elastomer.

[0013] The present application was made in view of the above-described aspect, and provides a vibration isolation device that can be mounted on a vehicle, and is capable of supplying a larger current to a magneto-rheological elastomer of a variable stiffness bush assembly, to increase the magnetic flux density inside the magneto-rheological elastomer of the variable stiffness bush assembly in accordance with the current supplied to the variable stiffness bush assembly, and to obtain a larger change in stiffness.

[0014] [Technical Means for Solving the Problems]

[0015] To achieve the above-described object, the present application is a vibration isolation device that can be mounted on a vehicle, the vibration isolation device including: a variable stiffness bush assembly; and a collar member composed of a magnetic material; the variable stiffness bush assembly having: an inner tube composed of a magnetic material, and having a hollow shaft portion for fastening to the vehicle; an outer tube composed of a magnetic material, and disposed coaxially with the inner tube on the radially outer side of the inner tube; a magneto-rheological elastomer disposed between the inner tube and the outer tube; and a coil that applies a magnetic field that changes the viscoelasticity of the magneto-rheological elastomer, wherein the collar member is in contact with the axial end portion of the inner tube of the variable stiffness bush assembly.

[0016] Thus, by disposing the collar member composed of a magnetic material at the axial end portion of the inner tube and in contact with the axial end portion of the inner tube, a larger current can be supplied to the variable stiffness bush assembly to increase the magnetic flux density of the magneto-rheological elastomer of the variable stiffness bush assembly, and a larger change in stiffness can be obtained.

[0017] In one embodiment of the present application, the vibration isolation device further includes: a fastened member composed of a magnetic material, and the collar member is in contact with the fastened member.

[0018] Thus, by superimposing the amount of the increased cross-sectional area of the fastened member again, a greater magnitude of the rigidity change can be obtained.

[0019] In one embodiment of the present application, the fastened member has a through-hole coaxial with the hollow shaft portion, and the collar member is in contact with the inner surface of the through-hole.

[0020] Thus, by increasing the contact area between the collar member and the fastened member, the cross-sectional area of the magnetic path can be increased.

[0021] In one embodiment of the present application, the variable rigidity bush assembly, the collar member, and the fastened member are fastened by a fastening element composed of a magnetic body.

[0022] Thus, by superimposing the amount of the increased cross-sectional area of the fastening element composed of a magnetic body again, the cross-sectional area of the magnetic path can be increased.

[0023] In one embodiment of the present application, the collar member is disposed in the through-hole of the fastened member in a press fit.

[0024] Thus, by pressing the collar member into the through-hole of the fastened member, the collar member and the fastened member can be brought into contact surely.

[0025] In one embodiment of the present application, the outer diameter of the inner ring portion of the collar member, which is in contact with the inner cylinder, is larger than the outer diameter of the inner cylinder.

[0026] Thus, the cross-sectional area of the magnetic path between the collar member and the fastened member can be ensured to be maximum.

[0027] In one embodiment of the present application, the vibration isolation device is used for a shaft bush of a suspension arm of a vehicle.

[0028] Thus, by providing the vibration isolation device in the shaft bush of the suspension arm of the vehicle, since the rigidity of the shaft bush of the suspension arm can be made variable, the vehicle can take both the ride quality performance and the vibration noise performance into consideration, in which the rigidity can be increased when the ride quality performance is desired to be essential, and the rigidity can be decreased when the vibration noise performance is desired to be essential, and accordingly, a vibration isolation device in which both the ride quality performance and the vibration noise performance can be taken into consideration can be provided.

[0029] [Effects of the Invention]

[0030] Based on the above, the vibration isolation device of the present application, by arranging the collar member composed of a magnetic body at the axial end portion of the inner tube and in contact with the axial end portion of the inner tube, can make a larger current flow through the variable stiffness bushing assembly to increase the magnetic flux density of the magnetorheological elastomer of the variable stiffness bushing assembly, and a greater change in rigidity can be achieved. In addition, by grounding the collar member composed of a magnetic body to the inner tube as a magnetic circuit, the cross-sectional area of the magnetic circuit in the coil can be increased, and the amount of cross-sectional area of the magnetic circuit in the coil that is increased is the amount of cross-sectional area that is increased by providing the collar member. Accordingly, the value of the applied current when the magnetic flux density on the cross section of the magnetic circuit in the coil reaches saturation becomes larger, and thus a greater change in rigidity can be achieved. In addition, the amount of cross-sectional area of the magnetic circuit can be adjusted conveniently by the shape of the collar member, and the magnetic flux density inside the magnetorheological elastomer can be increased to achieve a greater change in rigidity.

[0031] In order to make the above features and advantages of the present application more apparent, specific examples are described below, and the detailed description is made below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a partially omitted cross-sectional view schematically showing a vibration isolation device according to an embodiment of the present application being fastened to a vehicle frame.

[0033] Figure 2A is a schematic view showing the state of a magnetorheological elastomer structure of a basic structure in a case where no external force in the shearing direction is applied.

[0034] Figure 2B is a schematic view showing the state of a magnetorheological elastomer structure of a basic structure that is deflected in the lateral direction by an external force in the shearing direction being applied.

[0035] Figure 2C is a schematic view showing the state of a magnetorheological elastomer structure of a basic structure in which the resistance is increased when a magnetic field in the up-down direction is applied.

[0036] BRIEF DESCRIPTION OF DRAWINGS

[0037] 1: Vibration isolation device

[0038] 110: Variable stiffness bushing assembly

[0039] 112: Outer tube

[0040] 112E: Axial end portion

[0041] 112H: Hollow shaft portion

[0042] 114: Inner tube

[0043] 116: Magnetorheological elastomer

[0044] 118: coil

[0045] 120: collar member

[0046] 120E: outer ring portion

[0047] 120I: inner ring portion

[0048] 130: fastened member

[0049] 130H: through-hole

[0050] 140: fastening element

[0051] 140B: bolt

[0052] 140N: nut DETAILED DESCRIPTION

[0053] Hereinafter, an embodiment of the present application will be described with reference to the drawings. In the following described embodiment, unless otherwise specifically noted, the scope of the present application is not limited to the number, amount, etc. In addition, in the following embodiment, each component is not necessarily essential to the present application, unless otherwise specifically noted. In addition, in the following, when there are multiple embodiments, unless otherwise specifically noted, the characteristic portions of each embodiment can be appropriately combined from the outset.

[0054] Hereinafter, a preferred embodiment will be described with reference to the drawings for a vibration isolating device for mounting on a mounting bracket for a sub-frame of a vehicle frame to which the present application pertains.

[0055] Figure 1 is a partially omitted cross-sectional view schematically showing a vibration isolating device pertaining to one embodiment of the present application fastened to a vehicle frame. Figure 1 is a partially schematic view of a vibration isolating device fastened to a sub-frame in a mounted state, for example, by way of a mounting bracket to a vehicle body (for example, a main frame). Please refer to Figure 1 The vibration isolating device 1 of the present application can be mounted on a mounting bracket of a vehicle, and a sub-frame of the vehicle can be coupled to a main frame via the mounting bracket. A steered wheel of the vehicle is coupled and suspended to the main frame and the sub-frame by a suspension device (not shown), wherein the steered wheel is coupled to a steering wheel (not shown) via a rack mechanism and a steering shaft.

[0056] Here, first, before explaining the structure and the effect of the vibration isolating device 1 pertaining to the present embodiment, for ease of understanding, please refer to Figure 2A , Figure 2B and Figure 2CAn effect of the basic structure of the magnetorheological elastomer structure 100 (structure of the magnetorheological elastomer (MRE) 116 described below) will be described. Figure 2A is a schematic view showing a state of the basic structure of the magnetorheological elastomer structure when no external force in the shearing direction is applied. Figure 2B is a schematic view showing a state of the basic structure of the magnetorheological elastomer structure which is deflected in the lateral direction when an external force in the shearing direction is applied. Figure 2C is a schematic view showing a state in which a resistance is increased on the basic structure of the magnetorheological elastomer structure when a magnetic field in the up-down direction is applied.

[0057] Figure 2A A state of the magnetorheological elastomer structure 100 when no external force in the shearing direction (shearing stress) is applied is shown. In the magnetorheological elastomer structure 100 in Figure 2A , the magnetorheological elastomer member 108 in which the elastomer 106, which is silicone rubber or the like having, for example, iron powder 104 as magnetic particles oriented in the up-down direction, is cured is arranged between the upper support 101 and the lower support 102.

[0058] As shown in Figure 2B , for example, in a state where the lower support 102 is fixed to a base (not shown), if an external force in the shearing direction is applied to the upper support 101, the magnetorheological elastomer member 108 is deflected in the lateral direction in which the external force in the shearing direction is applied. In this case, the elastomer 106 generates a resistance against the external force in the shearing direction to want to return to the original shape.

[0059] As shown in Figure 2C , at this time, if a magnetic flux (magnetic field) shown by a dotted arrow in the up-down direction is applied, a resistance in a direction shown by a short arrow in which the iron powder 104 wants to return to a direction in line with the direction of the magnetic flux is increased. On the upper side of the magnetorheological elastomer structure 100, the resistance shown by a short arrow from right to left is increased, and on the lower side of the magnetorheological elastomer structure 100, the resistance shown by an arrow from left to right is increased. The larger the magnetic field, the larger the value of the resistance. In this way, in the magnetorheological elastomer structure 100, it is possible to change (make variable) the resistance with respect to the external force in the shearing direction according to the size of the applied magnetic field.

[0060] Accordingly, for example, in a mount in which the vibration isolation device 1 of the present application is installed, the greater the yaw rate obtained by a yaw rate sensor and the greater the vehicle speed obtained by a vehicle speed sensor, the greater the coil exciting current of a coil, and accordingly, the greater the resistance of the mount, i.e., the greater the elastic fixation (variability) of the mount. Therefore, for example, when traveling on a straight road or when cruising on a highway, the elastic softness of the mount is made by the vehicle control device setting the coil exciting current to zero or a small value, the forced vibration input from the internal combustion engine or the electric motor is cut off, and in addition, the vibration input from the road surface via the suspension to the main vehicle body is blocked, as a result, the sound and vibration felt by the passenger in the passenger compartment are suppressed, and thus the comfort is improved. On the other hand, in a so-called curved road or winding road, the elastic fixation (variability) of the mount is made by the vehicle control device increasing the coil exciting current, the performance of the vehicle (turning performance) is improved, and thus the operability (steering stability) of the driver is improved.

[0061] In the vibration isolation device 1 of the embodiment of the present application, in order to be able to supply a greater current to the magnetorheological elastomer, to correspondingly increase the magnetic flux density in the interior of the magnetorheological elastomer according to the supplied current, to obtain a greater change in stiffness. Please refer to Figure 1 , the vibration isolation device 1 includes a variable stiffness bushing assembly 110 and a collar member 120. The variable stiffness bushing assembly 110 is composed of a cylindrical inner cylinder 112, a cylindrical outer cylinder 114, a magnetorheological elastomer 116, and a coil 118. The inner cylinder 112 is composed of a magnet and has a hollow shaft portion 112H for fastening to a vehicle. The outer cylinder 114 is composed of a magnet and is disposed coaxially with the inner cylinder 112 on the radially outer side of the inner cylinder 112. The magnetorheological elastomer 116 is disposed between the inner cylinder 112 and the outer cylinder 114. The coil 118 applies a magnetic field that changes the viscoelasticity of the magnetorheological elastomer 116. The collar member 120 is in contact with the axial end portion 112E of the inner cylinder 112 of the variable stiffness bushing assembly 110.

[0062] A cylindrical coil (excitation coil) 118 is housed on the sidewall of the cylindrical inner cylinder 112. Coil 118 generates a magnetic field of strength corresponding to the magnitude of the coil excitation current supplied from the vehicle's electronic control unit (ECU) (not shown). A magnetorheological elastomer 116 is held between the inner cylinder 112 and the outer cylinder 114. The magnetorheological elastomer 116 is a component whose viscoelastic properties change depending on the magnitude of the magnetic field generated by the excitation coil 118. Specifically, the magnetorheological elastomer 116 is made of an elastic material, such as a rubber material, to which magnetic powder, such as iron powder, is added. Its rigidity is low when there is no magnetic field generated by coil 118 (or when the magnetic field is low). When there is a magnetic field generated by coil 118, its rigidity increases depending on the magnitude of the magnetic field.

[0063] So, like Figure 1 As shown, by arranging the ring member 120 composed of a magnetic body at the axial end 112E of the inner cylinder 112 and contacting the axial end 112E of the inner cylinder 112, a larger current can flow through the variable stiffness bushing assembly 110 to increase the magnetic flux density of the magnetorheological elastomer 116 of the variable stiffness bushing assembly 110, thereby achieving a larger stiffness change.

[0064] Furthermore, by grounding the magnetic collar member 120 to the inner cylinder 112, which generates the magnetic circuit, the cross-sectional area of ​​the magnetic circuit within the coil 118 can be increased. The amount of cross-sectional area increased by the collar member 120 is the same as the amount of cross-sectional area increased by the collar member 120. Consequently, the value of the applied current at which the saturated magnetic flux density is reached in the cross-section of the magnetic circuit within the coil 112 increases, thereby achieving a greater change in rigidity. Furthermore, the cross-sectional area of ​​the magnetic circuit can be conveniently adjusted by the shape of the collar member 120, thereby increasing the magnetic flux density within the magnetorheological elastomer 116 and achieving a greater change in rigidity.

[0065] Please refer to Figure 1 In this embodiment, in the anti-vibration device 1, the collar members 120 are provided at both ends of the variable stiffness bushing assembly 110 in the axial direction, and the collar members 120 are in contact with the axial end 112E of the inner tube 112 and also in contact with the fastening portion of the vehicle body (i.e., the fastened member 130). The collar member 120 is located between the axial end 112E of the inner tube 112 and the fastened member 130. The fastened member 130 in contact with the collar member 120 is composed of a magnetic body. More specifically, as Figure 1As shown, the fastened member 130 has a through-hole 130H that is coaxial with the hollow shaft portion 112H of the inner cylinder 112, and the collar member 120 is in contact with the inner surface of the through-hole 130H. In this way, by superimposing the amount of the increased cross-sectional area of the fastened member 130 composed of a magnetic body, a greater amplitude of rigidity change can be obtained. In other words, by increasing the contact area between the collar member 120 and the fastened member 130, the cross-sectional area of the generated magnetic path is also increased.

[0066] Further, in the present embodiment, the variable rigidity bush assembly 110, the collar member 120, and the fastened member 130 are fastened by the fastening element 140 composed of a magnetic body. As shown, Figure 1 As shown, the fastening element 140 is composed of, for example, a bolt 140B and a nut 140N, and in the present embodiment, the fastening between the variable rigidity bush assembly 110, the collar member 120, and the fastened member 130 is performed using the fastening element 140 composed of a magnetic body. In this way, by superimposing the amount of the increased cross-sectional area of the fastening element 140 composed of a magnetic body, the cross-sectional area of the magnetic path can be increased, and thus the magnetic flux density becomes higher, so the amplitude of rigidity change increases.

[0067] Further, in the present embodiment, the collar member 120 is provided in a press fitting manner, that is, the collar member 120 is pressed into the through-hole 130H of the fastened member 130. In this way, by pressing the collar member 120 into the through-hole 130H of the fastened member 130, the collar member 120 and the fastened member 130 can be brought into contact.

[0068] Further, in the present embodiment, as shown, Figure 1 The collar member 120 is designed to have an inner ring portion 120I and an outer ring portion 120E having different outer diameters, in which the inner ring portion 120I of the collar member 120 is in contact with the inner cylinder 112, and the outer ring portion 120E is in contact with the through-hole 130H of the fastened member 130. Accordingly, since the collar member 120 is provided in a press fitting manner between the axial end portion 112E of the inner cylinder 112 and the fastened member 130, as shown, Figure 1 As shown, the side surface of the inner ring portion 120I of the collar member 120 can be brought into contact with the side surface of the axial end portion 112E of the inner cylinder 112, and the outer wall surface of the outer ring portion 120E can be brought into contact with the inner wall surface of the through-hole 130H of the fastened member 130.

[0069] As shown, Figure 1As shown, the inner ring portion 120I of the collar member 120 is designed such that the outer diameter of the inner ring portion 120I is larger than the outer diameter of the inner cylinder 112. In this way, the limited space is used as much as possible, and the structure shape of the collar member 120 is adjusted conveniently, so that the cross-sectional area of the magnetic circuit generated between the collar member 120 and the fastening member 130 can be ensured to be maximum, so that the magnetic flux density is high, and the amplitude of the rigidity change is increased.

[0070] Further, in the present embodiment, the vibration isolation device 1 is used for the bushing of the suspension arm of the vehicle (for example, the above-mentioned sub frame). The vibration isolation device 1 of the present application is a structure that can be used as a suspension arm bushing and a sub frame mounting bushing, is a mounting bushing using a magnetorheological elastomer, can control the rigidity of the mounting bushing by applying an electric current to the magnetorheological elastomer, and can make the rigidity of the suspension arm bushing and the sub frame mounting bushing variable, so as to increase the rigidity when the ride quality performance is required, and to decrease the rigidity when the vibration noise performance is required, thereby being able to simultaneously achieve the ride quality performance and the vibration noise performance.

[0071] In this way, by arranging the vibration isolation device 1 at the bushing of the suspension arm of the vehicle, since the rigidity of the bushing of the suspension arm can be made variable, the vehicle can take into account both the ride quality performance and the vibration noise performance, wherein the rigidity can be increased when the ride quality performance is required, and the rigidity can be decreased when the vibration noise performance is required, thereby being able to provide a vibration isolation device that can take into account both the ride quality performance and the vibration noise performance.

[0072] In summary, the vibration isolation device of the present application, by arranging the collar member composed of a magnetic body at the axial direction end portion of the inner cylinder and in contact with the axial direction end portion of the inner cylinder, can make a larger current flow through the variable rigidity bushing assembly to increase the magnetic flux density of the magnetorheological elastomer of the variable rigidity bushing assembly, and can obtain a larger rigidity change. Further, by grounding the collar member composed of a magnetic body to the inner cylinder as a magnetic circuit generator, the cross-sectional area of the magnetic circuit in the coil can be increased, and the amount of the cross-sectional area of the magnetic circuit in the coil increased by the collar member is the amount of the cross-sectional area increased by the collar member. Accordingly, the value of the applied current when the magnetic flux density on the cross section of the magnetic circuit in the coil reaches saturation is increased. Further, the amount of the cross-sectional area of the magnetic circuit can be conveniently adjusted by the shape of the collar member, and the magnetic flux density inside the magnetorheological elastomer can be improved to obtain a larger rigidity change.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; even though the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An anti-vibration device characterized by comprising: A vibration isolation device mountable to a vehicle, the vibration isolation device comprising: a variable stiffness bushing assembly; and a collar member composed of a magnetic body; the variable stiffness bushing assembly has: an inner tube composed of a magnetic body and having a hollow shaft portion for fastening to the vehicle; an outer tube composed of a magnetic body and disposed coaxially with the inner tube on a radially outer side of the inner tube; a magnetorheological elastomer disposed between the inner tube and the outer tube; and a coil that applies a magnetic field that causes a change in viscoelasticity of the magnetorheological elastomer, wherein the vibration isolation device further includes a fastened member composed of a magnetic body, the fastened member having a through-hole with a coaxial relationship with the hollow shaft portion, the collar member is disposed between an axial end portion of the inner tube in the variable stiffness bushing assembly and the fastened member, and has an inner ring portion and an outer ring portion with different outer diameters, the inner ring portion of the collar member is in contact with the axial end portion of the inner tube, and an outer wall surface of the outer ring portion is in contact with an inner wall surface of the through-hole of the fastened member.

2. The vibration isolation device of claim 1, wherein the variable stiffness bushing assembly, the collar member, and the fastened member are fastened by a fastening element composed of a magnetic body.

3. The vibration isolation device of claim 1, wherein the collar member is disposed in the through-hole of the fastened member in a press fit manner.

4. The vibration isolation device according to any one of claims 1 to 3, characterized by an outer diameter of the inner ring portion of the collar member that is in contact with the inner tube is larger than an outer diameter of the inner tube.

5. The vibration isolation device according to any one of claims 1 to 3, characterized by the vibration isolation device is for a shaft bushing of a suspension arm of a vehicle.

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