Strut mount

Abstract

To provide a strut mount capable of improving durability while ensuring a static spring characteristic.SOLUTION: In a strut mount 1, a stopper part 70 of an insulator 10 comprises a protrusion 73 that protrudes radially outward on its outer surface 70a. When a load in an axial O direction is input to an inside member 30, a stopper part 70 is compressed by a lower metal fitting 21 and an end surface 35 in the axial O direction of the inside member 30. At this time, the protrusion 73 comes into contact with an opposing surface 21c of the lower metal fitting 21, to increase a frictional force generated between the stopper part 70 and the lower metal fitting 21. This improves durability while maintaining a static spring characteristic when the load in the axial O direction is input.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a strut mount, and more particularly to a strut mount that can improve durability while ensuring static spring characteristics.

Background Art

[0002] An upper support (strut mount) for suppressing vibrations transmitted from a shock absorber to a vehicle body is known (Patent Document 1). The upper support has a cylindrical inner fitting (inner member) attached to the rod tip of the shock absorber, an outer cylindrical fitting (outer member) surrounding the inner fitting and attached to the vehicle body, and an annular main body rubber elastic body (elastic connection part) interposed between the inner fitting and the outer cylindrical fitting and composed of the same elastic body for each part.

[0003] The main body rubber elastic body includes an upper contact projection and a lower contact projection (stopper part) that project from both sides in the axial direction from a portion connecting the outer peripheral surface of the inner fitting and the inner peripheral surface of the outer cylindrical fitting. The outer cylindrical fitting includes a pair of rebound stopper parts and a pair of bounce stopper parts (opposing surfaces) that are opposed in the axial direction and are configured to be able to contact the upper contact projection and the lower contact projection.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional technology described above, when the static spring characteristic was set low, the displacement amount of the stopper portion increased and the durability tended to decrease. To solve this problem, for example, when the entire stopper portion was thickened or the hardness of the elastic body of the elastic coupling portion was increased to suppress the displacement amount of the stopper portion, the static spring characteristic tended to increase. That is, there was a problem that the durability could not be improved while ensuring the static spring characteristic of the strut mount.

[0006] The present invention has been made to solve the above-described problems, and an object thereof is to provide a strut mount capable of improving durability while ensuring static spring characteristics.

Means for Solving the Problems

[0007] To achieve this object, the strut mount of the present invention includes a cylindrical inner member attached to the rod tip of a shock absorber, a cylindrical tubular member surrounding the inner member with a space from the outer peripheral surface of the inner member, and an annular elastic coupling portion interposed between the inner member and the tubular member and each part of which is composed of the same elastic body. The strut mount further includes an outer member that surrounds the insulator and is attached to the vehicle body. The elastic coupling portion includes a main body portion connecting the outer peripheral surface of the inner member and the inner peripheral surface of the tubular member, and stopper portions protruding from both end surfaces on both sides in the axial direction of the main body portion and the inner member to both sides in the axial direction. The outer member includes a pair of opposing surfaces configured to face each other in the axial direction and be able to contact the stopper portions. Protrusions are provided on at least one of the outer surface of the stopper portion or the opposing surfaces.

Effects of the Invention

[0008] According to the strut mount described in claim 1, the elastic coupling part includes a main body part that connects the outer peripheral surface of the inner member and the inner peripheral surface of the cylindrical member, and stopper parts that project axially on both sides from the end surfaces on both sides in the axial direction of the main body part and the inner member. The outer member includes a pair of opposing surfaces that face each other in the axial direction and are configured to be able to contact the stopper parts. Protrusions are provided on at least one of the outer surface of the stopper part or the opposing surface. Therefore, when a relatively high load is applied axially to the inner member, the protrusions of the stopper part contact the opposing surface, or the protrusions of the opposing surface contact the stopper part, increasing the frictional force generated between the stopper part and the opposing surface. As a result, the radial (axial perpendicular direction) movement (sliding) of the stopper part with respect to the opposing surface is suppressed, making it easier for the axial load to be received by the stopper part and suppressing the axial displacement (compressive strain) of the elastic coupling part. Thus, durability can be improved.

[0009] Also, when a relatively low axial load is applied to the inner member such that radial (axial perpendicular direction) movement (sliding) of the stopper part with respect to the opposing surface does not occur, the elastic coupling part does not have a large difference in the amount of axial displacement depending on the presence or absence of protrusions, so static spring characteristics can be ensured. Thus, it is possible to improve durability while ensuring static spring characteristics.

[0010] According to the strut mount described in claim 2, in addition to the effects achieved by the strut mount described in claim 1, since the protrusions are provided only on the outer surface of the stopper part, it is possible to make it difficult for the stopper part to be worn away by the opposing surface when the stopper part and the opposing surface come into contact. Thus, durability can be improved.

[0011] According to the strut mount described in claim 3, in addition to the effects achieved by the strut mount described in claim 2, since the protrusions are formed as ridges, the rigidity of the protrusions can be improved and the durability of the protrusions can be ensured. Thus, durability can be improved.

[0012] In addition, since the protrusion is a rib extending in the circumferential direction, when an axial load is applied to the inner member, the area where the protrusion contacts the opposing surface can be increased. Therefore, the frictional force generated between the stopper portion and the opposing surface can be increased.

[0013] According to the strut mount described in claim 4, in addition to the effect of the strut mount described in claim 2, the stopper portion includes a base portion that is connected to the inner member and the main body portion and is formed in an annular shape when viewed in the axial direction, a plurality of first protrusions and second protrusions that protrude axially outward from the base portion and are alternately arranged in the circumferential direction, and a groove formed between the first protrusions and the second protrusions in the circumferential direction. The first protrusion is set to have an axial length longer than that of the second protrusion, and the protrusion is provided at a portion axially outside the axial tip of the second protrusion among the first protrusions. Therefore, compared to the case where the protrusion is also provided at a portion axially inside the axial tip of the second protrusion of the stopper portion (the first protrusion and the second protrusion), the protrusion can be provided only at a portion that easily contributes to the effect of increasing the frictional force generated between the stopper portion and the opposing surface. Thereby, the protrusions at the portions that hardly contribute to the effect of increasing the frictional force generated between the stopper portion and the opposing surface can be eliminated, and the manufacturing cost can be suppressed.

[0014] According to the strut mount described in claim 5, in addition to the effect of the strut mount described in claim 2, the protrusions are provided on both the inner circumferential surface radially inside and the outer circumferential surface radially outside of the outer surface, and the axial height positions of the protrusions are set to be substantially the same on the inner circumferential surface and the outer circumferential surface of the outer surface. Therefore, when an axial load is applied to the inner member, the positions where the protrusions contact the opposing surface can be made substantially the same on the inner circumferential surface and the outer circumferential surface of the stopper portion. Thus, it is possible to suppress the stopper portion from moving (sliding) to either the inner side or the outer side in the radial direction with respect to the opposing surface. As a result, it becomes easier for the stopper portion to receive the axial load, and the axial displacement (compressive strain) of the elastic coupling portion is suppressed. Therefore, the durability can be improved.

[0015] According to the strut mount described in claim 6, in addition to the effect of the strut mount described in claim 2, since a plurality of protrusions are arranged side by side in the axial direction, when the compression deformation of the stopper portion progresses step by step, the protrusions are brought into contact with the opposing surface in order from the tip side in the axial direction, and the contact area between the protrusion and the opposing surface can be increased step by step. Therefore, the frictional force generated between the protrusion and the opposing surface can be easily increased step by step as the displacement of the stopper portion in the axial direction increases. As a result, the displacement amount of the stopper portion can be suppressed and the durability can be improved.

[0016] According to the strut mount described in claim 7, in addition to the effect of the strut mount described in claim 6, in a cross section cut along a plane including the axis of the inner member and passing through the protrusion, the apex of the protrusion is located on the outer side in the axial direction of the protrusion. Therefore, when the opposing surface comes into contact and the stopper portion is compressed and deformed, it is difficult to make the protrusion lie on the opposing surface compared to the case where the apex of the protrusion is located on the inner side in the axial direction of the (1) protrusion, and it is easy to make the protrusion contact the opposing surface in a relatively perpendicular posture. Therefore, the frictional force generated between the protrusion and the opposing surface can be increased. As a result, the durability can be improved.

[0017] According to the strut mount described in claim 8, in addition to the effect of the strut mount described in claim 4, the radial thickness of the base is set to be larger than the radial thicknesses of the first protrusion and the second protrusion, and an enlarged portion that protrudes radially outward beyond the outer peripheral surfaces of the first protrusion and the second protrusion is provided on the entire circumference of the outer peripheral surface of the base. Therefore, compared to the case where the enlarged portion is not provided, the stopper portion can be brought into contact with the cylindrical member earlier. Therefore, the amount of deformation of the stopper portion radially outward can be suppressed. As a result, the durability can be improved.

[0018] According to the strut mount described in claim 9, in addition to the effect of the strut mount described in claim 8, since the axial tip of the enlarged portion is located axially outside the axial end surface of the cylindrical member, even if the stopper portion is compressed and deformed by an axial load, the enlarged portion can be easily brought into contact with the inner peripheral surface of the cylindrical member. Therefore, the durability can be improved.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0020] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view of a strut mount 1 in one embodiment of the present invention. In FIG. 1, the arrow U-D in the figure indicates the vertical direction of the strut mount 1 (the same applies to the insulator 10 in FIGS. 3 to 7 and FIG. 8).

[0021] As shown in FIG. 1, the strut mount 1 is attached to the upper part of a suspension strut (not shown) in order to prevent vibrations and impacts from the wheels from being directly transmitted to the vehicle body. The strut mount 1 includes an insulator 10 and an outer member 20 that surrounds the insulator 10 from the outside.

[0022] The insulator 10 includes a cylindrical inner member 30, a cylindrical tubular member 40 surrounding the outer periphery of the inner member 30, and an elastic connecting portion 50 made of an elastic body that connects the outer peripheral surface 34 of the inner member 30 and the inner peripheral surface 41 of the tubular member 40.

[0023] The strut mount 1 receives an input from the wheel by the inner member 30, and the outer member 20 is fixed to the vehicle body. The load input to the inner member 30 is buffered by the elastic connecting portion 50 to suppress vibrations to the vehicle body. The present invention can improve durability while ensuring the static spring characteristics of the strut mount 1 by means of protrusions 73 (described later) provided on the elastic connecting portion 50. Hereinafter, each part will be described in detail.

[0024] In the present embodiment, the outer member 20 includes a lower fitting 21 and an upper fitting 22 that are flat plate-shaped and substantially triangular in top view and are arranged to face each other in the axial direction O of the inner member 30. The lower fitting 21 and the upper fitting 22 are provided with flanges 21a, 22a that project radially outward. The strut mount 1 is attached to the vehicle body by bolts B fixed to the flanges 21a, 22a.

[0025] Holes 21b, 22b penetrating in the axial direction O are formed at the centers of the lower fitting 21 and the upper fitting 22, respectively. Further, on a pair of opposing surfaces 21c, 22c of the lower fitting 21 and the upper fitting 22 that face each other in the axial direction O, a stopper portion 70 (described later) of the insulator 10 is sandwiched in the axial direction O in a pre-compressed state between the pair of opposing surfaces 21c, 22c.

[0026] Next, with reference to FIGS. 2 and 3, the insulator 10 will be described. FIG. 2 is a bottom view of the insulator 10 viewed from the direction of arrow II in FIG. 1. FIG. 3 is a cross-sectional view of the insulator 10 taken along line III-III in FIG. 2.

[0027] As shown in FIGS. 2 and 3, the inner member 30 is attached to the tip of the shock absorber rod R (see FIG. 1), and is a stepped cylindrical metal member to which vibrations from the shock absorber are transmitted. The inner member 30 includes a cylindrical small-diameter portion 31 and a cylindrical large-diameter portion 32 that is connected above the small-diameter portion 31 and has an outer diameter set larger than that of the small-diameter portion 31. A hole 33 penetrating in the direction of axis O is formed at the centers of the small-diameter portion 31 and the large-diameter portion 32. The tip of the shock absorber rod R is inserted into the hole 33, and the shock absorber is fixed to the inner member 30.

[0028] The cylindrical member 40 is a cylindrical metal member that surrounds the inner member 30 on the radially outer side. The cylindrical member 40 is press-fitted into the inner peripheral surface of the lower fitting 21 of the outer member 20 (see FIG. 1). The axis of the cylindrical member 40 coincides with the axis O of the inner member 30 in a state before the stopper portion 70 is pre-compressed by the outer member 20.

[0029] The length of the cylindrical member 40 in the vertical direction (axis O direction) is set to be longer than the length of the large-diameter portion 32 of the inner member 30 in the vertical direction, and each of the end faces 42 on both sides in the vertical direction of the cylindrical member 40 is located outside the end faces 35 of the large-diameter portion 32 of the inner member 30 in the axis O direction.

[0030] An annular elastic connecting portion 50 composed of the same elastic body for each part is interposed and joined between the inner peripheral surface 41 of the cylindrical member 40 and the outer peripheral surface 34 of the large-diameter portion 32 of the inner member 30. As the elastic body, for example, rubber, a thermoplastic elastomer, or the like can be adopted.

[0031] As shown in FIG. 3, the elastic connecting portion 50 is a member for buffering vibrations input from the shock absorber rod R to the inner member 30. The elastic connecting portion 50 includes a main body portion 60 that connects the outer peripheral surface 34 of the large-diameter portion 32 of the inner member 30 and the inner peripheral surface 41 of the cylindrical member 40, a stopper portion 70 that protrudes from both end faces 35 on both sides in the axis O direction of the main body portion 60 and the inner member 30 in both directions of the axis O, and a recess 61 that is recessed inward in the axis O direction at a position radially outside the stopper portion 70 and radially inside the cylindrical member 40. The recesses 61 are formed on both sides in the axis O direction.

[0032] Referring to FIGS. 4 to 6, each part of the stopper portion 70 will be described. FIG. 4 is a partial cross-sectional view of the insulator 10 taken along line IV-IV in FIG. 2. FIG. 5 is a partial cross-sectional view of the insulator 10 taken along line V-V in FIG. 2. FIG. 6 is a partial cross-sectional view of the insulator 10 taken along line VI-VI in FIG. 2.

[0033] Note that FIG. 4 is a cross-section cut by a plane including the axis O and passing through the circumferential center of the first protruding portion 72 of the stopper portion 70. FIG. 5 is a cross-section cut by a plane including the axis O and passing through the circumferential center of the second protruding portion 74 of the stopper portion 70. FIG. 6 is a cross-section cut by a plane including the axis O and passing through the circumferential center of the groove 75 of the stopper portion 70. In FIGS. 5 and 6, the same parts as those in FIG. 4 are denoted by the same reference numerals and their description is omitted.

[0034] As shown in FIGS. 4 to 6, the outer surface 70a of the stopper portion 70 includes an outer peripheral surface 70a1 which is a radially outer surface and an inner peripheral surface 70a2 which is a radially inner surface. The stopper portion 70 includes a base portion 71 connected to the end surfaces 35 of the main body portion 60 and the inner member 30, and a first protruding portion 72 and a second protruding portion 74 protruding further in the direction of the axis O from the base portion 71. A plurality (four each in this embodiment) of the first protruding portions 72 and the second protruding portions 74 are alternately arranged in the circumferential direction. A groove 75 recessed inward in the direction of the axis O is formed between the first protruding portion 72 and the second protruding portion 74 in the circumferential direction (see FIG. 2).

[0035] The base portion 71 is a portion inside the axis O direction from an imaginary line L1 drawn perpendicular to the axis O from the most recessed portion in the axis O direction of the groove 75 in the stopper portion 70.

[0036] The first protrusion 72 and the second protrusion 74 are shaped such that the radial thickness decreases from the inner side to the outer side in the direction of the axis O. Also, the length of the first protrusion 72 in the direction of the axis O is set to be longer than the length of the second protrusion 74 in the direction of the axis O. Therefore, in the present embodiment, when the insulator 10 is sandwiched by the outer member 20, it is pre-compressed by the outer member 20, and only the tip side of the first protrusion 72 is in a deformed state. In this state, the protrusion 73 is set so as not to contact the opposing surfaces 21c and 22c.

[0037] As shown in FIG. 4, on the outer peripheral surface 70a1 and the inner peripheral surface 70a2 of the first protrusion 72, a plurality of protrusions 73 (in this embodiment, three each on the outer peripheral surface 70a1 and the inner peripheral surface 70a2) protruding from the respective surfaces are arranged side by side in the direction of the axis O. The length by which the protrusion 73 protrudes from the outer peripheral surface 70a1 and the inner peripheral surface 70a2 (hereinafter referred to as "the length of the protrusion 73") is set to be sufficiently shorter than the length of the first protrusion 72 in the direction of the axis O. For example, the length of the protrusion 73 is set to be about 3% of the length of the first protrusion 72 in the direction of the axis O. Note that the length of the protrusion 73 may be less than 3% of the length of the first protrusion 72 in the direction of the axis O. In the present embodiment, the protrusion 73 is formed only on the lower stopper portion 70 (the first protrusion 72).

[0038] The protrusions 73 arranged side by side on the outer peripheral surface 70a1 have the same position in the direction of the axis O as the protrusions 73 arranged side by side on the inner peripheral surface 70a2.

[0039] The apex 73a of the protrusion 73 is located on the other end portion 73c side (outer side in the direction of the axis O) rather than on the one end portion 73b side between the one end portion 73b on the inner side and the other end portion 73c on the outer side of the protrusion 73 in the direction of the axis O. Note that the apex 73a of the protrusion 73 is the point that is most distant perpendicularly from the outer surface 70a of the stopper portion 70.

[0040] On the base portion 71, an enlarged portion 71a that projects radially outward from the outer peripheral surface 70a1 is formed. The enlarged portion 71a is a portion that projects radially outward beyond a virtual line L2 connecting an end point 61a on the radially inner side of the arc of the concave portion 61 and an end point 70b on the outer peripheral surface 70a1 side of the first protruding portion 72 in a cross section (see FIG. 4) cut by a plane including the axis O of the inner member 30 and passing through the first protruding portion 72. Note that the end point 70b is the intersection of the virtual line L1 and the outer peripheral surface 70a1 of the first protruding portion 72.

[0041] The enlarged portion 71a has a radially decreasing thickness as it extends from the outer side to the inner side in the direction of the axis O. Also, the enlarged portion 71a is formed over the entire circumference of the base portion 71 (see FIGS. 2 and 7). The tip 71a1 of the enlarged portion 71a is located on the inner side in the direction of the axis O with respect to the virtual line L1.

[0042] Note that on the tip of the stopper portion 70 (on the outer side in the direction of the axis O from the portion where the protrusion 73 is formed), a dimple (small protrusion) is formed to suppress abnormal noise generated when the lower fitting 21 and the upper fitting 22 come into contact with the tip of the stopper portion 70. The height of the protrusion 73 from the outer surface 70a is set to be sufficiently higher than the height of the dimple from the outer surface 70a.

[0043] As shown in FIG. 5, the second protruding portion 74 is a portion that protrudes outward in the direction of the axis O from the base portion 71 of the stopper portion 70. The radial thickness of the base portion 71 connected to the second protruding portion 74 is made substantially the same as the thickness of the base portion 71 connected to the first protruding portion 72.

[0044] An enlarged portion 71a that projects radially outward from the outer peripheral surface 70a1 is also formed on the base portion 71 connected to the second protruding portion 74, similar to the base portion 71 connected to the first protruding portion 72.

[0045] In addition, in the present embodiment, the second protruding portion 74 is composed of two types of protruding portions, a long protruding portion 74a having a relatively long length in the direction of the axis O and a short protruding portion 74b having a length set shorter than that of the long protruding portion 74a in the direction of the axis O (see FIG. 7). The long protruding portions 74a are located at two positions facing each other in the radial direction, and the short protruding portions 74b are located at two positions facing each other in the radial direction so as to be orthogonal to the facing direction of the two long protruding portions 74a (see FIG. 2). The second protruding portion 74 can vary the timing at which the long protruding portion 74a and the short protruding portion 74b come into contact with the opposing surfaces 21c and 22c.

[0046] As shown in FIG. 6, the groove 75 is a portion that is recessed inward in the direction of the axis O between the first protruding portion 72 and the second protruding portion 74 in the circumferential direction. The radial thickness of the base portion 71 connected to the groove 75 is made substantially the same as the thickness of the base portion 71 connected to the first protruding portion 72 and the second protruding portion 74.

[0047] An enlarged portion 71a that protrudes radially outward from the outer peripheral surface 70a1 is also formed on the base portion 71 connected to the groove 75, similar to the base portion 71 connected to the first protruding portion 72 and the second protruding portion 74.

[0048] Referring to FIG. 7, the shape of the stopper portion 70 in side view will be described. FIG. 7 is a side view of the insulator 10 viewed from the direction of arrow VII in FIG. 2. In FIG. 7, the cylindrical member 40 is omitted from the illustration. As shown in FIG. 7, the protrusion 73 has a ridge shape extending in the circumferential direction.

[0049] The manufacturing method of the strut mount 1 is as follows. First, after setting the inner member 30 and the cylindrical member 40 in a vulcanization mold (not shown), an elastic body is filled into the cavity of the mold, and pressurized and heated to vulcanize and bond the elastic connecting portion 50 to the inner member 30 and the cylindrical member 40 to obtain the insulator 10. Next, the cylindrical member 40 of the insulator 10 is fitted (press-fitted) inside the lower fitting 21, and the upper fitting 22 is joined to the lower fitting 21 to obtain the strut mount 1.

[0050] The vertex 73a of the protrusion 73 is located on the other end 73c side (outer side in the axial direction of the axis O) rather than the one end 73b side between the one end 73b inside in the axial direction of the axis O of one protrusion 73 and the other end 73c outside in the axial direction of the axis O. Therefore, with respect to the die-cutting direction, the angle at which the slope of the protrusion 73 on the one end 73b side inclines (the angle of the slope where resistance occurs when forced extraction is performed) can be reduced. Thus, even when the insulator 10 is forced out from the vulcanization mold, compared with the protrusion shape in which the vertex 73a of the protrusion 73 is located on the one end 73b side rather than the other end 73c side, breakage of the protrusion 73 can be suppressed.

[0051] Next, with reference to FIG. 8, the deformation mode of the insulator 10 when a load in the axial direction of the axis O is input to the strut mount 1 (inner member 30) will be described. FIG. 8(a) is a partial cross-sectional view of the strut mount 1 at the start of input of the load downward in the axial direction of the axis O, FIG. 8(b) is a partial cross-sectional view of the strut mount 1 when a further load downward in the axial direction of the axis O is applied from FIG. 8(a), and FIG. 8(c) is a partial cross-sectional view of the strut mount 1 when a further load downward in the axial direction of the axis O is applied from FIG. 8(b).

[0052] As shown in FIG. 8(a), the insulator 10 of the strut mount 1 is sandwiched in the axial direction of the axis O between the lower fitting 21 and the upper fitting 22 of the outer member 20. Since the stopper portion 70 of the insulator 10 is pre-compressed by the lower fitting 21 and the upper fitting 22, the tip of the first protruding portion 72 is crushed. At this time, although not shown, the tip of the second protruding portion 74 is not in contact with the lower fitting 21 and the upper fitting 22 and is in a state of not being pre-compressed.

[0053] In this state, when the vehicle attempts to cross a depression in the road surface or the like, a load for displacing the inner member 30 downward in the axial direction of the axis O is input via the rod R of the shock absorber. As a result, the first protruding portion 72 is pressed between the lower end surface 35 on the lower side of the inner member 30 and the opposing surface 21c of the lower fitting 21, and the tip side of the first protruding portion 72 is further crushed.

[0054] As shown in FIG. 8(b), the plurality of protrusions 73 formed on the outer surfaces 70a (the outer peripheral surface 70a1 and the inner peripheral surface 70a2) on the tip side of the first protrusion 72 sequentially come into contact with the opposing surface 21c from the protrusions 73 on the tip side of the first protrusion 72 toward the protrusions 73 on the rear end side. In this state, two of the three protrusions 73 on each of the outer peripheral surface 70a1 and the inner peripheral surface 70a2 are in contact with the opposing surface 21c.

[0055] Next, as shown in FIG. 8(c), when a load is further applied in the axial direction of the axis O, the tip side of the first protrusion 72 is further crushed, and a part of the first protrusion 72 is deformed so as to move in the circumferential direction. A part of the first protrusion 72 that has moved in the circumferential direction moves into the groove 75 and fills the groove 75. Then, when the tip of the first protrusion 72 is further crushed, the tip of the second protrusion 74 comes into contact with the opposing surface 21c of the lower fitting 21. At this time, since a part of the first protrusion 72 has already moved into and filled the groove 75, even if the first protrusion 72 and the second protrusion 74 are crushed, the first protrusion 72 and the second protrusion 74 cannot move any further in the circumferential direction, and they are deformed so as to escape radially outward and radially inward. At this time, all three of the protrusions 73 are in contact with the opposing surface 21c.

[0056] As described above, when a load is gradually input in the axial direction of the axis O to the inner member 30, along with the compressive deformation of the first protrusion 72, the protrusions 73 on the tip side of the first protrusion 72 come into contact with the opposing surface 21c in order from the protrusions 73 on the rear end side.

[0057] Here, in the present embodiment, the static spring characteristics of the strut mount 1 are measured in a first range in which a relatively small load in the axial direction of the axis O is input to the inner member 30, and the durability of the strut mount 1 is measured in a second range wider than the range in which the static spring characteristics are measured (a range in which a relatively large load in the axial direction of the axis O is input to the inner member 30).

[0058] In the first range and the second range, the load from the inner member 30 is transmitted to the elastic connecting portion 50, causing the elastic connecting portion 50 to elastically deform. In the first range, since the load input in the axial direction O to the inner member 30 is relatively small, it is difficult to compress the first protruding portion 72 between the opposing surface 21c and the end surface 35 of the inner member 30. Therefore, it is difficult for the repulsive force of the compressive deformation of the stopper portion 70 to act on the protrusion 73, and the protrusion 73 is difficult to be pressed against the opposing surface 21c. Thus, it is difficult for a frictional force to occur between the protrusion 73 and the opposing surface 21c.

[0059] In addition to the fact that it is difficult for a frictional force to occur between the protrusion 73 and the opposing surface 21c, the length of the protrusion 73 is set to be sufficiently shorter than the length of the first protruding portion 72 in the axial direction O. Therefore, in the first range where the protrusion 73 is difficult to be pressed against the opposing surface 21c, the presence or absence of the protrusion 73 has little influence on the spring characteristics of the insulator 10, and it is easy to maintain the spring characteristics at a low level.

[0060] On the other hand, in the second range, since the load input in the axial direction O to the inner member 30 is relatively larger than that in the first range, it is easy to compress the first protruding portion 72 between the opposing surface 21c and the end surface 35 of the inner member 30. Therefore, the protrusion 73 formed on the first protruding portion 72 is pressed against the opposing surface 21c by the repulsive force of the compressive deformation of the stopper portion 70. As a result, the frictional force generated between the first protruding portion 72 and the opposing surface 21c can be increased.

[0061] Thereby, the movement (sliding) of the first protruding portion 72 in the radially outer and inner directions with respect to the opposing surface 21c is suppressed, so that the load received from the opposing surface 21c can be easily received vertically by the first protruding portion 72. Therefore, compared with the case where the protrusion 73 is not formed on the first protruding portion 72, it is easy to suppress the displacement (compressive strain) in the axial direction O of the elastic connecting portion 50 with respect to the same load. As a result, the durability can be improved.

[0062] From the above, according to the strut mount 1 of the present embodiment, since the protrusion 73 is provided on the outer surface 70a of the stopper portion 70 (the first protruding portion 72 in the present embodiment), in the first range where a relatively small load in the axial direction O is input to the inner member 30, while maintaining the static spring characteristics low, in the second range where a relatively large load in the axial direction O is input to the inner member 30, the durability can be improved.

[0063] Further, since the plurality of protrusions 73 are arranged side by side in the axial direction O, in accordance with the behavior in which a load in the axial direction O is input to the inner member 30 and the first protruding portion 72 is gradually compressed and deformed, the protrusions 73 on the tip side in the axial direction O can be brought into contact with the opposing surface 21c in order. Therefore, the frictional force generated between the first protruding portion 72 and the opposing surface 21c can be increased.

[0064] The apex 73a of the protrusion 73 is located on the other end portion 73c side (outer side in the axial direction O) rather than the one end portion 73b side between the one end portion 73b on the inner side in the axial direction O and the other end portion 73c on the outer side of one protrusion 73. Therefore, when a load in the axial direction O is input to the inner member 30 and the first protruding portion 72 is deformed, the load received from the opposing surface 21c can be easily received vertically by the protrusion 73. Thus, the radial movement (sliding) of the first protruding portion 72 with respect to the opposing surface 21c can be suppressed, and the displacement (compressive strain) of the elastic coupling portion 50 can be easily suppressed.

[0065] Since the positions of the protrusions 73 arranged side by side on the outer peripheral surface 70a1 in the axial direction O are the same as those of the protrusions 73 arranged side by side on the inner peripheral surface 70a2, when a load in the axial direction O is input to the inner member 30 and the first protruding portion 72 is deformed, the positions where the protrusions 73 formed on the outer peripheral surface 70a1 and the inner peripheral surface 70a2 come into contact with the opposing surface 21c can be made substantially the same. Thereby, it is possible to suppress the first protruding portion 72 from moving (sliding) either radially outward or radially inward with respect to the opposing surface 21c. As a result, it is easy to make the first protruding portion 72 receive a load vertically with respect to the lower fitting 21. Therefore, when a relatively large load is input, the amount of displacement (compressive strain) in the axial direction O of the elastic coupling portion 50 can be suppressed. Thereby, the durability of the elastic coupling portion 50 can be improved.

[0066] Since the protrusion 73 has a rib shape, the rigidity of the protrusion 73 itself can be improved. Therefore, the durability of the insulator 10 can be improved.

[0067] The first protrusion 72 is brought into contact with the opposing surface 21c so as to be pressed against the opposing surface 21c and sequentially expand the thickness in the radial direction. Since the protrusion 73 is a rib extending in the circumferential direction, the protrusion 73 can be brought into contact with the opposing surface 21c so as to inhibit the progress of the expansion of the first protrusion 72 with respect to the direction in which the first protrusion 72 expands. Therefore, compared with the case where the protrusion is a rib extending in the direction of the axis O, it is easier to apply the frictional force generated between the stopper portion 70 (protrusion 73) and the opposing surface 21c.

[0068] Further, as shown in FIG. 8(c), when the load in the direction of the axis O of the inner member 30 progresses, the stopper portion 70 bulges outward in the radial direction, and the outer peripheral surface 70a1 of the stopper portion 70 comes into contact with the inner peripheral surface 41 of the cylindrical member 40. Thereby, the deformation of the stopper portion 70 outward in the radial direction is restricted.

[0069] When the stopper portion 70 bulges outward in the radial direction, it comes into contact with the inner peripheral surface 41 of the cylindrical member 40 and the deformation outward in the radial direction is restricted, so the displacement of the elastic connecting portion 50 in the direction of the axis O is suppressed. However, when the distance between the outer peripheral surface 70a1 of the stopper portion 70 and the inner peripheral surface 41 of the cylindrical member 40 is large, the amount of deformation of the stopper portion 70 until the deformation in the radial direction is restricted becomes large.

[0070] On the other hand, according to the strut mount 1 of the present embodiment, since the enlarged portion 71a is formed on the outer peripheral surface 70a1 of the stopper portion 70, when a load in the direction of the axis O is input to the inner member 30, compared with the case where the enlarged portion 71a is not formed, it is easier to bring the outer peripheral surface 70a1 of the stopper portion 70 into contact with the inner peripheral surface 41 of the cylindrical member 40. Therefore, the amount of deformation in the radial direction until the stopper portion 70 comes into contact with the inner peripheral surface 41 of the cylindrical member 40 can be reduced, and thereby, the displacement of the elastic connecting portion 50 in the direction of the axis O is suppressed. As a result, the durability of the elastic connecting portion 50 can be improved.

[0071] Further, since the tip 71a1 of the enlarged portion 71a in the axial direction of the axis O is located outside in the axial direction of the axis O from the end face 42 of the cylindrical member 40 in the axial direction of the axis O, even if the stopper portion 70 is deformed and bulges radially outward, it is possible to easily bring the entire enlarged portion 71a into contact with the outer peripheral surface 70a1 of the cylindrical member 40. Therefore, the amount of deformation of the stopper portion 70 in the radial direction when a load is input in the axial direction of the axis O can be reduced. As a result, the durability of the elastic coupling portion 50 can be improved.

[0072] The enlarged portion 71a has a reduced radial thickness as it extends from the outside to the inside in the axial direction of the axis O. Therefore, it is possible to make it difficult to affect the displacement of the stopper portion 70 in the axial direction orthogonal to the axial direction of the axis O. Therefore, the static spring characteristics in the axial direction can be kept low.

[0073] Since the tip 71a1 of the enlarged portion 71a is located inside in the axial direction of the axis O from the virtual line L1, it is possible to prevent the radial thicknesses of the first protruding portion 72 and the second protruding portion 74 from becoming unnecessarily thick due to the enlarged portion 71a. Therefore, the static spring characteristics of the first protruding portion 72 and the second protruding portion 74 can be kept low. As a result, it is possible to hardly impair the functions of the first protruding portion 72 and the second protruding portion 74, which is to obtain multi-stage spring characteristics by bringing the first protruding portion 72 and the second protruding portion 74 into contact with the fitting in order.

[0074] Although the present invention has been described based on the embodiments, it can be easily inferred that the present invention is not limited to the above embodiments at all, and various improvements and modifications are possible without departing from the spirit of the present invention.

[0075] In the above embodiment, the case where the protrusion 73 is formed on the lower stopper portion 70 has been described. However, the protrusion 73 may be formed on the upper stopper portion 70 or on the stopper portions 70 on both the upper and lower sides.

[0076] In the above embodiment, the case where the first protruding portion 72 and the second protruding portion 74 protrude from both sides of the base portion 71 in the axial direction of the axis O has been described. However, only the first protruding portion 72 may be the protruding portion that protrudes from both sides of the base portion 71 in the axial direction of the axis O. In this case, the groove 75 is omitted.

[0077] In addition to the first protrusion 72 and the second protrusion 74, a third protrusion whose length in the direction of the axis O is shorter than that of the second protrusion 74 may protrude from both sides or one side of the base 71 in the direction of the axis O. In this case, the first protrusion 72, the second protrusion 74, and the third protrusion are alternately arranged in the circumferential direction in this order, and a groove 75 is formed between the protrusions in the circumferential direction. In addition to the third protrusion, a plurality of protrusions whose lengths in the direction of the axis O are sequentially set shorter may be provided.

[0078] In the above embodiment, the case where the apex 73a of the protrusion 73 is located on the other end portion 73c side rather than the one end portion 73b side has been described, but the apex 73a of the protrusion 73 may be located on the one end portion 73b side rather than the other end portion 73c side.

[0079] In the above embodiment, the case where the protrusion 73 is formed on both sides (the outer peripheral surface 70a1 and the inner peripheral surface 70a2) of the outer surface 70a has been described, but the protrusion 73 may be formed on either the outer peripheral surface 70a1 or the inner peripheral surface 70a2 of the outer surface 70a.

[0080] In the above embodiment, the case where the protrusion 73 is formed only on the first protrusion 72 has been described, but in addition to the first protrusion 72, the protrusion 73 may also be formed on the second protrusion 74. In this case, it may be formed on either the long protrusion 74a or the short protrusion 74b, or may be formed on both.

[0081] In the above embodiment, the case where the protrusion 73 is a ridge extending in the circumferential direction has been described, but the protrusion 73 does not have to be a ridge. For example, a plurality of convex protrusions may protrude from the outer surface 70a.

[0082] In the above embodiment, the case where a plurality of protrusions 73 are formed has been described, but there may be one protrusion.

[0083] In the above-described embodiment, the case where the protrusion 73 is formed only on the stopper portion 70 has been described. However, the protrusion 73 may be formed on the opposing surfaces 21c and 22c. Further, it may be formed on both the stopper portion 70 and the opposing surfaces 21c and 22c. In this case, the protrusions formed on the opposing surfaces 21c and 22c are formed at portions that come into contact when the stopper portion 70 is compressed.

[0084] In the above-described embodiment, the case where the heights of the protrusions 73 on the outer peripheral surface 70a1 and the inner peripheral surface 70a2 are the same has been described. However, the heights of the protrusions 73 on the outer peripheral surface 70a1 and the inner peripheral surface 70a2 may be different.

[0085] In the above-described embodiment, the case where a part of the outer peripheral surface 70a1 of the base portion 71 is linear in a cross section cut by a plane including the axis O and passing through the first protruding portion 72 or the second protruding portion 74 has been described. However, the entire outer peripheral surface 70a1 of the base portion 71 may be curved.

[0086] In the above-described embodiment, the case where the tip 71a1 of the enlarged portion 71a is disposed outside the end surface 42 of the cylindrical member 40 in the direction of the axis O has been described. However, the tip 71a1 may be disposed inside the end surface 42 of the cylindrical member 40 in the direction of the axis O. Note that the enlarged portion 71a may be omitted.

[0087] In the above-described embodiment, the case where the radial thickness of the enlarged portion 71a is constant in the circumferential direction has been described. However, it may be different in the circumferential direction. For example, in the base portion 71 connected to the first protruding portion 72, the thickness of the enlarged portion 71a is set to be thin, and conversely, in the base portion 71 connected to the second protruding portion 74, the thickness of the enlarged portion 71a is set to be thick. In this case, it is possible to easily bring the timings at which the enlarged portions 71a of the base portions 71 connected to the first protruding portion 72 and the second protruding portion 74 come into contact with the inner peripheral surface 41 of the cylindrical member 40 closer.

[0088] Also, for example, in the base portion 71 connected to the first protruding portion 72, the thickness of the enlarged portion 71a may be set to be thick, and conversely, in the base portion 71 connected to the second protruding portion 74, the thickness of the enlarged portion 71a may be set to be thin.

Explanation of Reference Numerals

[0089] 1 Strut Mount 10 Insulator 20 Outer Member 21c, 22c Opposing Surfaces 30 Inner Member 34 Outer Peripheral Surface 35 End Surface 40 Cylindrical Member 42 End Surface 50 Elastic Connection Portion 60 Main Body Portion 70 Stopper Portion 70a Outer Surface 70a1 Outer Peripheral Surface 70a2 Inner Peripheral Surface 71 Base 71a Enlarged Portion 71a1 Tip 72 First Protruding Portion 73 Protrusion 73a Apex 74 Second Protruding Portion 75 Groove O Axis

Claims

1. A cylindrical inner member attached to the rod tip of a shock absorber, a cylindrical tubular member surrounding the inner member with a gap from the outer peripheral surface of the inner member, and an annular elastic connecting portion interposed between the inner member and the tubular member and composed of the same elastic body for each part, and an insulator having the same; In a strut mount including an outer member that surrounds the insulator and is attached to a vehicle body, The elastic connecting portion includes a main body portion connecting the outer peripheral surface of the inner member and the inner peripheral surface of the tubular member, and stopper portions protruding from both end surfaces on both sides in the axial direction of the main body portion and the inner member to both sides in the axial direction; The outer member includes a pair of opposing surfaces configured to face each other in the axial direction and be able to contact the stopper portions; A strut mount, characterized in that a protrusion is provided on at least one of the outer surface of the stopper portion or the opposing surface.

2. The strut mount according to claim 1, wherein the protrusion is provided only on the outer surface of the stopper portion.

3. The strut mount according to claim 2, wherein the protrusion is a ridge extending in the circumferential direction.

4. The stopper portion includes a base portion connected to the inner member and the main body portion and formed in an annular shape in an axial view, a plurality of first protrusions and second protrusions protruding axially outward from the base portion and alternately arranged in the circumferential direction, and a groove formed between the first protrusions and the second protrusions in the circumferential direction; The first protrusion is set to have a longer axial length than the second protrusion; The strut mount according to claim 2, wherein the protrusion is provided on a portion of the first protrusion that is axially outside the axial tip of the second protrusion.

5. The protrusion is provided on both the inner peripheral surface on the radially inner side and the outer peripheral surface on the radially outer side of the outer surface; The strut mount according to claim 2, wherein the axial height position of the protrusion is substantially the same height on the inner peripheral surface and the outer peripheral surface of the outer surface.

6. The strut mount according to claim 2, wherein a plurality of the protrusions are arranged in parallel in the axial direction.

7. In a cross section cut by a plane including the axis of the inner member and passing through the protrusion, the apex of the protrusion is located axially outside the protrusion. The strut mount according to claim 6.

8. The radial thickness of the base portion is set to be larger than the radial thicknesses of the first protruding portion and the second protruding portion. The strut mount according to claim 4, wherein an enlarged portion that protrudes radially outward beyond the outer peripheral surfaces of the first protruding portion and the second protruding portion is provided over the entire circumference of the outer peripheral surface of the base portion. **Claim 9** The strut mount according to claim 8, wherein the axial tip of the enlarged portion is located axially outside the axial end surface of the cylindrical member.

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