JP4870028B2 - Vibration isolator - Google Patents

Description

  The present invention relates to an anti-vibration device, and in particular, with non-linear spring characteristics, it is possible to improve durability and suppress generation of abnormal noise while improving ride comfort characteristics and steering stability of a vehicle. The present invention relates to a vibration device.

  A shock absorber that constitutes a suspension mechanism of a vehicle is provided with a cylindrical vibration isolator (bound stopper) formed of an elastic body such as rubber or urethane and is inserted into a piston rod. A cup-shaped mounting bracket is attached to the distal end side of the piston rod, and the upper end side of the vibration isolator is held in a fitted state in the mounting bracket.

  When bouncing due to the input of a heavy load, the lower surface of the vibration isolator (bound stopper) is brought into contact with the upper surface of the shock absorber cylinder, and is compressed and deformed in the axial direction between the upper surface of the cylinder and the seating surface of the mounting bracket. As a result, the excessive operating stroke in the contraction direction of the shock absorber is elastically limited.

  This anti-vibration device (bound stopper) is soft when the operating stroke of the shock absorber is small when limiting the operating stroke of the shock absorber described above in order to achieve both the riding comfort characteristics and the steering stability of the vehicle ( It is required to exhibit a non-linear spring characteristic such that the spring constant is small) and when the operating stroke is large, it is sufficiently hard (the spring constant is large).

Therefore, for example, Japanese Patent Application Laid-Open No. 2004-1000087 discloses a technique in which protrusions that elastically contact the upper surface of a cylinder are integrally formed at a plurality of locations at predetermined intervals in the circumferential direction on the lower surface of a vibration isolator (bound stopper). Is disclosed. By this protrusion, compared with the case where the lower surface of the vibration isolator contacts the upper surface of the shock absorber, the above-described spring characteristics can be made more non-linear (Patent Document 1).
JP 2004-100088 (paragraph [0035], FIG. 1 etc.)

  However, in the conventional vibration isolator described above, when the lower stroke of the vibration isolator is brought into contact with the upper surface of the cylinder when the operation stroke at the time of bouncing is restricted, the protrusion formed on the lower surface buckles. However, there is a problem in that the spring characteristics change suddenly and the ride comfort and steering stability of the vehicle are lowered. In addition, the conventional vibration isolator described above has a problem that the durability of the vibration isolator decreases due to buckling, and sufficiently reduces abnormal noise when contacting the upper surface of the cylinder. There was a problem that it was not possible.

  The present invention has been made to solve the above-described problems, and improves the riding comfort characteristics and steering stability of the vehicle by non-linear spring characteristics, while improving durability and suppressing the generation of abnormal noise. It aims at providing the vibration isolator which can aim at.

  In order to achieve this object, a vibration isolator according to claim 1 is provided with a cylindrical stopper body that is externally arranged on a piston rod of a shock absorber, and has a cup-like shape attached to the tip end side of the piston rod. The upper end portion of the stopper main body is held in the fitted state by the fitting holding portion, and the lower surface of the stopper main body is brought into contact with the upper surface of the cylinder, thereby elastically regulating the operation stroke of the shock absorber. The stopper body includes an insertion hole through which the piston rod is inserted, one or a plurality of circumferential grooves having a V-shaped cross-section that is recessed in the outer peripheral surface of the stopper body and is continuous in the circumferential direction, and the stopper A plurality of quadrangular pyramid-shaped protrusions projecting from the bottom surface of the main body and having a rectangular vertical cross section, and the plurality of protrusions are arranged at equal intervals around the eight insertion holes. The rectangular longitudinal direction in the vertical cross section is arranged radially along the radial direction of the insertion hole, and the quadrangular pyramid shape has a vertex positioned eccentrically outward in the radial direction with respect to the insertion hole, and a bottom surface. The height H is larger than the horizontal length W which is the short side of the bottom surface, and the height H is smaller than the vertical length L which is the long side of the bottom surface. It is comprised in the shape larger than the adjacent space | interval F in the said insertion hole side of a some protrusion.

  The anti-vibration device according to claim 2 is the anti-vibration device according to claim 1, wherein the circumferential groove is spaced apart from the first circumferential groove by a predetermined distance from the first circumferential groove. A second circumferential groove located on the upper surface side of the stopper body, and the opening width C, which is the groove width in the opening of the first circumferential groove and the second circumferential groove, is the vertical length of the bottom surface in the quadrangular pyramid shape The insertion hole has a first hole extending from the lower surface of the stopper body to a position reaching the first circumferential groove, and extends from the terminal end of the first hole to the upper surface of the stopper body, and the stopper body. And the stopper body has a thickness t2 of the constricted portion due to the second circumferential groove larger than a thickness t1 of the constricted portion due to the first circumferential groove. It is thinned.

  According to the vibration isolator of the first aspect, when the bouncing is caused by the input of a large load, the stopper body is compressed and deformed in the axial direction between the seating surface of the fitting holding portion and the upper surface of the cylinder. Excessive operating stroke in the direction of contraction of the absorber is elastically limited. In this case, a plurality of protrusions protruding from the lower surface of the stopper main body are brought into contact with the upper surface of the cylinder, and the plurality of protrusions are elastically deformed.

  As a result, when the operating stroke of the shock absorber is limited, in the region where the operating stroke is small, the upper surface of the cylinder is softly received by elastic deformation of the plurality of protrusions, and the rise of the load in the load-deflection curve is increased. On the other hand, in a region where the operating stroke is large, a plurality of sufficiently compressed and deformed protrusions are stretched to increase the load gradient in the load-deflection curve (spring). As a result, the spring characteristics are made non-linear so that both the riding comfort characteristics and the steering stability of the vehicle can be achieved.

  Here, according to the vibration isolator of the present invention, since the shape of the plurality of protrusions is a quadrangular pyramid shape whose vertical cross section is a rectangle, the operation is limited when limiting the operation stroke of the shock absorber at the time of bouncing. In a region with a small stroke, the plurality of protrusions can be easily deformed, and the deformation can be performed smoothly. Therefore, since the upper surface of the cylinder can be received softly, the rise of the load in the load-deflection curve can be made gentle (spring constant is reduced).

  On the other hand, by configuring the plurality of protrusions in the shape of a quadrangular pyramid as described above, when the deformation of the plurality of protrusions reaches a predetermined deformation amount in a region with a large operating stroke, Since the protrusion can be strung, the load gradient in the load-deflection curve can be increased (the spring constant can be increased).

  As a result, it is possible to achieve a balance between vehicle riding comfort characteristics and driving stability by achieving a non-linear spring characteristic in which the load rises with a large slope in the second half while maintaining a gentle rise in the initial stage. There is.

  In addition, according to the vibration isolator of the present invention, the plurality of protrusions are arranged at equal intervals on the lower surface of the stopper body and around the insertion hole, and the above-described quadrangular pyramid shape is formed in a laterally long side of the bottom surface. Since the length W is configured to be larger than the adjacent interval F on the insertion hole side of each protrusion, even if the lower surface of the stopper body is in contact with the upper surface of the cylinder in an inclined state, the lower surface As a result, it is possible to secure a state in which any one of the plurality of projecting portions projecting from the upper surface of the cylinder is in contact with the upper surface of the cylinder, and to surely exhibit a non-linear spring characteristic.

  That is, when the lower surface of the stopper body is in contact with the upper surface of the cylinder in an inclined state, which part of the lower surface of the stopper body (the circumferential position on the lower surface of the stopper body) is in contact with the upper surface of the cylinder However, the conventional product has a problem in that the contact state between the upper surface of the cylinder and the protrusion is not stable and the variation in spring characteristics increases. It was.

  On the other hand, according to the vibration isolator of the present invention, since the plurality of protrusions are arranged at equal intervals around the insertion hole, any part on the lower surface of the stopper body is brought into contact with the upper surface of the cylinder. Even in this case, any one of the plurality of protrusions protruding from the lower surface of the stopper body can be reliably brought into contact with the upper surface of the cylinder, and variation in the contact state can be reduced. Therefore, the non-linear spring characteristic can be stably exhibited.

  Further, in addition to the configuration described above, protrusions are provided at eight positions around the insertion holes, that is, at intervals of 45 degrees in the circumferential direction, and the lateral length W of the bottom surface in the quadrangular pyramid shape is adjacent to the insertion hole side of each protrusion. Since it is configured to be larger than the interval F, even if any part of the lower surface of the stopper main body is brought into contact with the upper surface of the cylinder, the plurality of protrusions protruding from the lower surface of the stopper main body. Any one can be reliably brought into contact with the upper surface of the cylinder, and variation in the contact state can be further reduced, so that the non-linear spring characteristic can be exhibited in a more stable state.

  Further, according to the vibration isolator of the present invention, the rectangular longitudinal direction in the vertical cross section is configured to dispose the plurality of protrusions radially along the radial direction of the insertion hole, so that the lower surface of the stopper body is directed to the upper surface of the cylinder. Even in the case of contact in an inclined state, a load acting on the protrusion from the upper surface of the cylinder can be received in the longitudinal direction of the protrusion, so that the protrusion can be prevented from buckling. There is an effect. As a result, the concentration of strain due to buckling can be suppressed and durability can be improved. In addition, it is possible to suppress a sudden change in the spring characteristics due to buckling and improve the ride comfort and steering stability of the vehicle.

  In addition, according to the vibration isolator of the present invention, the plurality of protrusions are arranged radially such that the longitudinal direction of the rectangle in the vertical cross section is along the radial direction of the insertion hole, and the apex of the quadrangular pyramid has a diameter with respect to the insertion hole. Since it is positioned eccentrically outward in the direction, when the protrusion projecting from the bottom surface of the stopper body contacts the top surface of the cylinder, the bottom surface of the stopper body (the inner peripheral surface of the insertion hole) Can be deformed in a direction away from the piston rod. Thereby, while being able to suppress that a stopper main body (inner peripheral surface of an insertion hole) contacts a piston rod and wears, it can suppress that the operating stroke of a piston rod can be inhibited. There is.

  In addition, according to the vibration isolator of the present invention, the shape of the protrusion is such that the height H is greater than the horizontal length W which is the short side of the bottom surface, and the vertical length L is the long side of the bottom surface. Since the configuration is a quadrangular pyramid shape with a smaller height H (W <H <L), the non-linear spring characteristics can improve the riding comfort characteristics and driving stability of the vehicle and are durable. There is an effect that it is possible to improve the performance and suppress the generation of abnormal noise.

  That is, as described above, the plurality of protrusions are arranged such that the longitudinal direction of the rectangle in the vertical section thereof is arranged along the radial direction of the insertion hole, and the apex of the quadrangular pyramid is radially outward with respect to the insertion hole. It is a structure that is positioned eccentrically to the side, and is a structure that supports the load from the upper surface of the cylinder at the time of bouncing in the rectangular longitudinal direction.

  Therefore, when the height H is smaller (lower) than the lateral length W, it is difficult to deform the projecting portion when the operating stroke of the shock absorber at the time of bouncing is restricted, and the compression is not smoothly deformed. The lower surface of the cylinder cannot be softly received. For this reason, the generation of abnormal noise is caused, and the rise of the initial load in the load-deflection curve is gradual (the spring constant cannot be reduced).

  On the other hand, when the height H is larger (higher) than the vertical length L, when the operating stroke of the shock absorber at the time of bouncing is limited, the buckling of the protrusion is caused and the durability due to the concentration of strain. In addition to a decrease, the spring characteristics change suddenly due to buckling, leading to a problem that the ride comfort and steering stability of the vehicle are reduced.

  On the other hand, in the vibration isolator of the present invention, since the shape of the protrusion (height H, horizontal and vertical lengths W, L) is configured as described above, the protrusion can be appropriately deformed. As a result, it is possible to improve the riding comfort characteristics and the steering stability of the vehicle, and to improve the durability and suppress the generation of abnormal noise.

  Moreover, according to the vibration isolator of the present invention, the shape of the protrusion is configured such that the lateral length W of the bottom surface is larger than the adjacent interval F on the insertion hole side between the protrusions. Therefore, there is an effect that the slope of the latter half of the load can be increased while the bottom area of the protrusion is secured and the initial rise of the load in the load-deflection curve is moderated. As a result, non-linear spring characteristics can be obtained, and the riding comfort characteristics and steering stability of the vehicle can be improved.

  According to the vibration isolator according to claim 2, in addition to the effect of the vibration isolator according to claim 1, the opening width C which is the groove width in the opening of the first circumferential groove and the second circumferential groove is a quadrangular pyramid shape. Is larger than the vertical length L of the bottom surface, i.e., the opening width C is larger than the height H and the vertical length L of the quadrangular pyramid shape, so that the stroke of the shock absorber when bounding is limited. In doing so, in the initial stage, the protrusion and the upper surface of the cylinder can be brought into contact with each other in a state where the circumferential groove is not filled.

  As a result, the upper surface of the cylinder can be received softer in the initial stage of limiting the operation stroke, so that the generation of abnormal noise can be suppressed and the rise of the initial load in the load-deflection curve is made more gradual. There is an effect that (the spring constant can be reduced).

  In addition, according to the vibration isolator of the present invention, the thickness t2 of the constricted portion due to the second circumferential groove is configured to be thinner than the thickness t1 of the constricted portion due to the first circumferential groove. These can be bent step by step with a difference.

  Thereby, when limiting the operating stroke of the shock absorber at the time of bounding, the timing at which the first circumferential groove is filled and the timing at which the second circumferential groove is filled can be made different, so in the initial stage of limiting the operating stroke The upper surface of the cylinder can be received softer. As a result, the occurrence of abnormal noise can be suppressed, and the rise of the initial load in the load-deflection curve can be made more gradual (spring constant can be reduced).

  Furthermore, according to the vibration isolator of the present invention, the first hole extending from the lower surface of the stopper body to the position extending to the first circumferential groove, and extending from the terminal end of the first hole to the upper surface of the stopper body and toward the upper surface of the stopper body. Since the first hole and the second hole have a difference in thickness between the constricted portions as described above, the first circumferential groove and the second hole are provided. Compared with the case where there is a difference in the groove depth, opening width, etc. between the circumferential grooves, the shape of the stopper body can be simplified, and the durability and the yield can be improved. is there. Further, by forming the second hole in a tapered shape, there is an effect that the mold can be easily removed from the vulcanization mold and the productivity can be improved. Furthermore, compared with the case where the first circumferential groove and the second circumferential groove have a difference in the groove depth, the opening width, etc., the non-linear characteristic of the load-deflection curve is effective, There is an effect that it is possible to improve riding comfort characteristics and steering stability.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a shock absorber 10 in which a bound stopper 100 according to an embodiment of the present invention is assembled. First, the attached state of the bound stopper 100 will be described with reference to FIG.

  The shock absorber 10 is one component in the suspension mechanism of the vehicle, and mainly includes a cylinder 11 and a piston rod 12 protruding from the cylinder 11 as shown in FIG. The piston rod 12 is elastically connected to the vehicle frame BF via the lower cushion rubber 20, the upper cushion rubber 30, the mounting bracket 40, and the pressing bracket 50.

  That is, the piston rod 12 is formed with a threaded portion 12a at the upper end portion (upper side in FIG. 1), and a flange portion 12b projecting radially outward at a position separated from the upper end portion by a predetermined distance. A nut N is screwed into the male screw portion 12a.

  Then, the mounting bracket 40 and the pressing bracket 50 are sandwiched in the axial direction (the vertical direction in FIG. 1) by the flange portion 12b and the nut N, and the lower cushion rubber 20 and the upper cushion rubber 30 are elastically pressed against the vehicle body frame BF. Thus, the piston rod 12 is elastically connected to the vehicle body frame BF.

  As shown in FIG. 1, the mounting bracket 40 is formed in a shape in which cup-shaped members are stacked back to back, and includes two storage spaces that are open on both the upper and lower sides. In the storage spaces on both the upper and lower sides (upper and lower sides in FIG. 1), the lower cushion rubber 20 and the lower end side and the upper end side of the bound stopper 100 which are arranged on the piston rod 12 are fitted and held. A cylindrical dust cover 60 that covers the exposed portion of the piston rod 12 is mounted on the outer peripheral surface of the mounting bracket 40.

  Here, the bound stopper 100 is compressed and deformed in the axial direction (vertical direction in FIG. 1) between the seating surface 40a of the mounting bracket 40 and the upper surface 11a of the cylinder 11 when bouncing due to the input of a large load. It is a member for elastically limiting an excessive operation stroke in the contraction direction of the shock absorber 10.

  As shown in FIG. 1, the bound stopper 100 is configured with a stopper main body 101 as a base, and an insertion hole 110 is formed in the center of the stopper main body 101 so that the piston rod 12 is inserted. A plurality of protrusions 120 project from the lower surface 101a (lower side surface in FIG. 1) of the stopper body 101, and are configured to be able to elastically contact the upper surface 11a of the cylinder 11. Further, a circumferential groove 130 having a V-shaped cross section that is continuous in the circumferential direction is provided in the outer peripheral surface of the stopper body 101.

  As shown in FIG. 1, an air discharge groove 101c as a concave groove extending from the upper surface 101b to the side surface is formed at the upper end portion (upper side in FIG. 1) of the bound stopper 100 (FIGS. 2 and 2). 3), and is configured to discharge compressed air between the mounting bracket 40 and the bound stopper 100 at the time of bounding.

  According to the suspension mechanism configured as described above, the stopper body 101 is axially positioned between the seating surface 40a of the mounting bracket 40 and the upper surface 11a of the cylinder 11 when bouncing due to an input of a large load (vertical direction in FIG. 1). By being compressed and deformed, the excessive operation stroke in the contraction direction of the shock absorber 10 is elastically limited. In this case, a plurality of protrusions 120 protruding from the lower surface 101a of the stopper main body 101 are brought into contact with the upper surface 11a of the cylinder 11, and the plurality of protrusions 120 are elastically deformed.

  As a result, when the operating stroke of the shock absorber 10 is limited, in the region where the operating stroke is small, the upper surface 11a of the cylinder 11 is softly received by the elastic deformation of the plurality of protrusions 120, and in the load-deflection curve. The rise of the load can be made gentle (spring constant is reduced). On the other hand, in a region where the operation stroke is large, a plurality of protrusions 120 that are sufficiently compressed and deformed are stretched to increase the load gradient in the load-deflection curve (increase the spring constant). As a result, the spring characteristics can be made non-linear so that both the riding comfort characteristics of the vehicle and the steering stability can be achieved.

  Next, the detailed configuration of the bound stopper 100 will be described with reference to FIGS. 2 to 5. FIG. 2A is a bottom view of the bound stopper 100, and FIG. 2B is a top view of the bound stopper 100. FIG. 3 is a cross-sectional view of the bound stopper 100 taken along line III-III in FIG.

  As shown in FIGS. 2 and 3, the bound stopper 100 includes a stopper main body 101 configured in a cylindrical shape from a rubber-like elastic material, and the stopper main body 101 includes an insertion hole 110, a circumferential groove 130, and a protrusion. The unit 120 is mainly provided.

  As described above, the insertion hole 110 is a part through which the piston rod 12 is inserted (see FIG. 1). As shown in FIGS. 2 and 3, the first hole 111 and the first hole 111 are continuously provided. The second hole 112 is provided. The first hole 111 and the second hole 112 are formed along the axis O, the first hole 111 is located on the lower surface 101a side of the stopper body 101, and the second hole 112 is formed on the stopper body 101. Located on the upper surface 101b side.

  The first hole 111 extends from the lower surface 101a of the stopper body 101 to a position reaching a groove bottom 131a of the first circumferential groove 131 described later (in the present embodiment, the first hole 131 is a groove of the first circumferential groove 131). The second hole 112 extends as far as a position exceeding the bottom 131a), and extends from the connecting portion (terminal) to the first hole 111 to the upper surface 101b of the stopper main body 101 and increases in diameter toward the upper surface 101b. It is configured.

  The protrusion 120 is a part for making the rise of the load moderate in the load-deflection curve, and is protruded from the lower surface 101a of the stopper main body 101 as shown in FIGS. The protrusions 120 are formed in a quadrangular pyramid shape in which a cross section perpendicular to the axis O (vertical cross section) is a rectangle, and are arranged at eight intervals around the insertion hole 110 (that is, at intervals of 45 degrees in the circumferential direction). Has been.

  Thus, according to the bound stopper 100 of the present invention, since the shape of the plurality of protrusions 120 is a quadrangular pyramid shape with a rectangular vertical cross section, the operating stroke of the shock absorber 10 at the time of bounding is limited. At this time, in a region where the operation stroke is small, the plurality of protrusions 120 can be easily deformed, and the deformation can be performed smoothly. Therefore, since the upper surface 11a (see FIG. 1) of the cylinder 11 can be received softly, the rise of the load in the load-deflection curve can be made gentle (spring constant is reduced).

  On the other hand, by configuring the plurality of protrusions 120 in the shape of a quadrangular pyramid as described above, when the deformation of the plurality of protrusions 120 reaches a predetermined deformation amount in a region where the operation stroke is large, the subsequent deformation is difficult. Since each protrusion 120 can be stretched, the load gradient in the load-deflection curve can be increased (the spring constant can be increased).

  As a result, when the operating stroke of the shock absorber 10 at the time of bouncing is limited by the bouncing stopper 100, a non-linear spring characteristic in which the load rises with a large slope in the latter half while achieving a gentle load rise in the initial stage is achieved. It is possible to achieve both the ride comfort characteristics and the steering stability.

  Here, as shown in FIG. 2A, the protrusions 120 are arranged so that the longitudinal direction of the rectangle in the vertical section is radial along the radial direction of the insertion hole 110, that is, the protrusions 120 are arranged with respect to the axis O. They are arranged in a radial line. Further, the protrusion 120 is positioned such that the apex (FIG. 2A, the front side on the paper surface) is eccentric to the radially outer side with respect to the insertion hole 110 (axis O) (see FIG. 5B). 2 (a), the virtual circle S formed by connecting these vertices is configured to be concentric with the insertion hole 110 when viewed in the axial center O direction.

  As described above, according to the bound stopper 100 of the present invention, since the protrusions 120 (longitudinal direction of the rectangle) are arranged radially along the radial direction of the insertion hole 110, the lower surface 101a of the stopper main body 101 is a cylinder. 11, the load acting on the protrusion 120 from the upper surface 11 a of the cylinder 11 is applied in the longitudinal direction of the protrusion 120 (FIG. 5B). ) In the left-right direction).

  Thereby, since it can suppress that the protrusion 120 buckles, while suppressing the concentration of the distortion resulting from the buckling, it can aim at the improvement of durability, and the spring characteristic resulting from buckling It is possible to improve the ride comfort and steering stability of the vehicle by suppressing the rapid change of the vehicle.

  Here, with reference to FIG.4 and FIG.5, the detailed structure of the protrusion 120 is demonstrated. FIG. 4 is a bottom view of the bound stopper 100 and corresponds to a partially enlarged view of FIG. 5A is a partially enlarged sectional view of the bound stopper 100 taken along the line Va-Va in FIG. 4, and FIG. 5B is a partially enlarged sectional view of the bound stopper 100 taken along the line Vb-Vb in FIG. FIG.

  As described above, each protrusion 120 is formed in a quadrangular pyramid shape whose vertical cross section is a rectangle, and this quadrangular pyramid shape has a vertical length that is the long side of the rectangle on the bottom surface as shown in FIG. 5, and the horizontal length, which is the short side of the rectangle on the bottom surface, is W and the height is H, as shown in FIG. In addition, each projection 120 has an interval (adjacent interval) F between adjacent projections 120.

  In addition, as shown in FIG. 4, the rectangular short side in the bottom face of the protrusion 120 is curved in the circular arc shape centering on the axial center O (refer Fig.2 (a)) in detail. Therefore, the vertical length L described above is defined as a length in a direction along an imaginary line connecting the apex of the quadrangular pyramid and the axis O.

  Thus, according to the bound stopper 100 of the present invention, as described above, the protrusions 120 are arranged at equal intervals on the lower surface 101a of the stopper main body 101 and around the insertion hole 110 (first hole 111). 4 (see FIG. 2A), as shown in FIG. 4, the rectangular lateral length W on the bottom surface of the quadrangular pyramid shape (projection 120) is set to the adjacent interval F between the projections 120 on the insertion hole 110 side. Even when the lower surface 101a of the stopper body 101 is in contact with the upper surface 11a of the cylinder 11 in an inclined state (see FIG. 1), the lower surface A state in which any of the plurality of protrusions 120 protruding from 11a abuts on the upper surface 11a of the cylinder 11 can be ensured, and the non-linear spring characteristics can be reliably exhibited.

  That is, when the lower surface 101a of the stopper body 101 is brought into contact with the upper surface 11a of the cylinder 11 in an inclined state, any part of the lower surface 101a of the stopper body 101 (on the lower surface 101a of the stopper body 101) is brought into contact with the upper surface 11a of the cylinder 11. Whether the circumferential position) is in contact with the mounting bracket 40 (see FIG. 1) varies depending on the assembly position of the stopper body 101 with respect to the mounting bracket 40, the running state, and the like. There is a problem that the contact state between the two is not stable and the variation in spring characteristics becomes large.

  On the other hand, according to the bound stopper 100 of the present invention, the plurality of protrusions 120 are arranged at equal intervals around the insertion hole 110 (first hole 111) (see FIG. 2). Even if any part of the lower surface 101 a of the cylinder 11 is in contact with the upper surface 11 a (see FIG. 1) of the cylinder 11, any one of the plurality of protrusions 120 protruding from the lower surface 101 a of the stopper body 101. Can be reliably brought into contact with the upper surface 11a of the cylinder 11, and variation in the contact state can be reduced, so that the non-linear spring characteristics can be stably exhibited.

  Further, according to the bound stopper 100 of the present invention, the quadrangular pyramid shape (projection 120) has a height H larger than the lateral length W of the rectangle on the bottom surface, and the rectangular and vertical length L on the bottom surface. Since the configuration is such that the height H is smaller than that (W <H <L), the non-linear spring characteristics can improve the riding comfort characteristics and driving stability of the vehicle, and the durability can be improved. Improvement and suppression of abnormal noise generation can be achieved.

  That is, as shown in FIG. 4, the plurality of protrusions 120 are arranged such that the longitudinal direction of the rectangle in the vertical section thereof is arranged along the radial direction of the insertion hole 110 (first hole 111), and FIG. As shown in FIG. 5, the apex of the quadrangular pyramid is eccentrically positioned on the radially outer side (the right side in FIG. 5B) with respect to the insertion hole 110 (the first term 111), and the cylinder at the time of bounding 11 is a structure that supports the load from the upper surface 11a (see FIG. 1) of the eleven in the longitudinal direction of the rectangle (left and right direction in FIG. 5A).

  Therefore, when the height H is smaller (lower) than the lateral length W, when the operating stroke of the shock absorber 10 at the time of bounding is restricted, the deformation of the protrusion 10 becomes difficult, and the protrusion 120 is Since it is not smoothly compressed and deformed, the lower surface 11a (see FIG. 1) of the cylinder 11 cannot be softly received. For this reason, the generation of abnormal noise is caused, and the rise of the initial load in the load-deflection curve is gradual (the spring constant cannot be reduced).

  On the other hand, when the height H is larger (higher) than the vertical length L, when the operating stroke of the shock absorber 10 at the time of bouncing is restricted, the protrusion 120 is buckled, and durability is increased due to concentration of strain. As a result, the spring characteristics suddenly change due to buckling, leading to a problem that the ride comfort and steering stability of the vehicle are reduced.

  On the other hand, in the bound stopper 100 of the present invention, since the shape of the protrusion 120 (height H, horizontal and vertical lengths W, L) is configured as described above, the protrusion 120 is appropriately deformed. As a result, it is possible to improve the riding comfort characteristics and the handling stability of the vehicle, and to improve the durability and suppress the generation of abnormal noise.

  Moreover, according to the bound stopper 100 of the present invention, the rectangular lateral length W on the bottom surface of the protrusion 120 is configured to be larger than the adjacent interval F on the insertion hole 110 (first hole 111) side. The bottom area of the portion 120 is ensured, the rise of the initial load in the load-deflection curve is gradual, and the slope of the latter half of the load can be increased.As a result, a non-linear spring characteristic can be obtained, It is possible to improve the riding comfort characteristics and the handling stability of the vehicle.

  Further, according to the bound stopper 100 of the present invention, as described above, the protrusions 120 (rectangular longitudinal direction) are arranged radially along the radial direction of the insertion hole 110 (see FIG. 2), and FIG. ), The apex of the quadrangular pyramid shape is positioned to be decentered radially outward with respect to the insertion hole 110, so that the protrusion 120 protruding from the lower surface 101a of the stopper body 101 is a cylinder. 11, the lower surface 101 a of the stopper body 101 is deformed in a direction away from the piston rod 12 (see FIG. 1), that is, the insertion hole 110 (first hole 111). ) Can be expanded.

  Thereby, it can suppress that the stopper main body 101 (inner peripheral surface of the insertion hole 110) contacts the piston rod 12, and the inner peripheral surface of the insertion hole 110 is abraded, and the operating stroke of the piston rod 12 is reduced. It is inhibited and it can suppress that a suspension function falls.

  Returning to FIG. 2 and FIG. The circumferential groove 130 is a part for gradual rising of the load in the load-deflection curve. As shown in FIG. 3, the circumferential groove 130 has a V-shaped cross-sectional shape that is recessed in the outer peripheral surface of the stopper main body 101 and is continuous in the circumferential direction. It is configured as a groove. The circumferential groove 130 includes a first circumferential groove 131 located on the lower surface 101a side of the stopper main body 101 and a second circumferential groove 132 located on the upper surface 101b side of the stopper main body 101 with a predetermined distance from the first circumferential groove 131. With.

  As shown in FIG. 3, the stopper main body 101 has a portion having the same outer diameter along the direction of the axis O, and the first circumferential groove 131 and the second circumferential groove 132 are recessed in the portion. . The first and second circumferential grooves 131 and 132 are arranged at positions where the groove bottoms 131a and 132a are at the same distance from the axis O, and the opening angles of the first and second circumferential grooves 131 and 132a are set to the same angle. The opening widths C, which are the groove widths (dimensions in the direction of the axis O), are the same length.

  Thus, according to the bound stopper 100 of the present invention, the opening width C, which is the groove width in the openings of the first circumferential groove 131 and the second circumferential groove 132, is greater than the vertical length L of the bottom surface in the quadrangular pyramid shape. Is larger, that is, the opening width C is larger than the height H and the vertical length L of the quadrangular pyramid shape (see FIGS. 4 and 5), so that the operating stroke of the shock absorber 10 at the time of bouncing is limited. In the initial stage, the projection 120 and the upper surface 11a of the cylinder 11 (see FIG. 1) are brought into contact with each other in a state where the circumferential groove 130 (the first and second circumferential grooves 131 and 132) is not filled. Can be made.

  Thus, in the initial stage of limiting the operation stroke, the upper surface 11a of the cylinder 11 can be received softer, so that the generation of abnormal noise can be suppressed and the rise of the initial load in the load-deflection curve is more gradual. (The spring constant can be reduced).

  Here, as described above, the first hole 111 is configured as a hole having a constant inner diameter along the axial center O direction (in the left-right direction in FIG. 3), and the second hole 112 is formed on the upper surface 101b side ( It is configured as a tapered hole whose inner diameter increases toward the left side of FIG. Therefore, the thickness t2 of the constricted portion by the second circumferential groove 132 can be made thinner than the thickness t1 of the constricted portion by the first circumferential groove 131 (t2 <t1). Can be bent in stages.

  Thereby, when restricting the operating stroke of the shock absorber 10 at the time of bounding, the timing at which the first circumferential groove 131 is filled and the timing at which the second circumferential groove 132 is filled can be made different, so that the operating stroke is limited. In the initial stage, the upper surface 11a (see FIG. 1) of the cylinder 11 can be received softer. As a result, the generation of abnormal noise can be suppressed, and the rise of the initial load in the load-deflection curve can be made more gradual (spring constant can be reduced).

  Furthermore, according to the bound stopper 100 of the present invention, as described above, the first and second circumferential grooves 131 and 132 are configured to have a difference in the thickness of the constricted portion (t2 <t1). Compared with the case where the groove depth and the opening width are different between the circumferential groove 131 and the second circumferential groove 132, the shape of the stopper main body 101 is simplified, and the durability and the yield are improved. Can be achieved.

  Further, as shown in FIG. 3, by forming the second hole 112 in a tapered shape, it is easy to remove the mold from the vulcanization mold, and the productivity can be improved. Furthermore, compared with the case where the first circumferential groove 131 and the second circumferential groove 132 are different in the groove depth, the opening width, etc., the non-linear characteristic of the load-deflection curve is effectively improved. It is possible to improve ride comfort characteristics and driving stability.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  For example, the numerical values (for example, the quantity, size, angle, etc. of each component) given in the above embodiment are merely examples, and other numerical values can naturally be adopted.

  Further, in the above embodiment, the groove bottoms 131 a and 132 a of the first circumferential groove 131 and the second circumferential groove 132 are arranged at the same distance from the axis O and are located on the upper surface 101 b side of the stopper main body 101. The case where the second hole 111 is configured as a hole whose inner diameter is increased in a tapered shape has been described. According to this configuration, when changing the thickness of the constricted portion, the opening area of the first hole 111 is made smaller than the opening area of the second hole 112, and the lower surface 101 a of the stopper body 101 is correspondingly reduced. An area can be secured. Thereby, since the area in the bottom face of the protrusion 120 can be ensured, it is possible to improve durability and suppress the generation of abnormal noise while improving the riding comfort characteristics and steering stability of the vehicle. .

  However, it is not necessarily limited to this configuration, and other configurations are naturally possible. For example, contrary to the above-described embodiment, the second hole 112 may be configured as a tapered hole whose diameter decreases from the connection portion with the first hole 111 toward the upper surface 101b. Also with this configuration, it is possible to change the thickness of the constricted portions.

  In the above embodiment, the case where the first hole 111 extends from the lower surface 101a of the stopper main body 101 to a position beyond the groove bottom 131a of the first circumferential groove 131 is not necessarily limited to this. The first hole 111 extends from the lower surface 101a of the stopper main body 101 and is terminated before reaching the groove bottom 131a of the first circumferential groove 131, and the second hole 112 extends from the upper surface 101b of the stopper main body 101 to the first circumferential groove 131. You may comprise so that it may extend to the position beyond the groove bottom 131a. In this case, the tapered shape of the second hole 112 may be such that the opening on the upper surface 101b side has a larger diameter as shown in FIG. 3 than the connecting portion with the first hole 111, or Small diameter may be sufficient.

It is sectional drawing of the shock absorber with which the bound stopper in one embodiment of this invention was assembled | attached. (A) is a bottom view of the bound stopper, (b) is a top view of the bound stopper. It is sectional drawing of the bound stopper in the III-III line of Fig.2 (a). It is a bottom view of a bound stopper, and corresponds to a partially enlarged view of FIG. (A) is the elements on larger scale of the bound stopper in the Va-Va line of FIG. 4, (b) is the elements on larger scale of the bound stopper in the Vb-Vb line of FIG.

Explanation of symbols

100 Bound stopper (anti-vibration device)
101 stopper body 101a stopper body bottom surface 101b stopper body top surface 110 insertion hole 111 first hole 112 second hole 120 protrusion 130 circumferential groove 131 first circumferential groove 132 second circumferential groove W horizontal length H height L vertical Length F adjacent spacing C opening width t1 wall thickness t2 of the constricted portion due to the first circumferential groove 10 thickness of constriction portion due to the second circumferential groove 10 shock absorber 11 cylinder 11a upper surface of the cylinder 12 piston rod 40 mounting fitting (fitting holding) Part)

Claims (2)

A cylindrical stopper body is provided on the piston rod of the shock absorber, and the upper end portion of the stopper body is held in a fitted state by a cup-shaped fitting holding portion attached to the distal end side of the piston rod. In addition, in the vibration isolator that elastically regulates the operating stroke of the shock absorber by contacting the lower surface of the stopper body with the upper surface of the cylinder,
The stopper main body includes an insertion hole through which the piston rod is inserted, one or a plurality of circumferential grooves having a V-shaped cross section that is recessed in the outer peripheral surface of the stopper main body and continues in the circumferential direction, and a lower surface of the stopper main body. A plurality of quadrangular pyramid-shaped protrusions protruding and having a rectangular vertical cross section
The plurality of protrusions are arranged at eight equal intervals around the insertion hole, and the longitudinal direction of the rectangle in the vertical section is arranged radially along the radial direction of the insertion hole,
The quadrangular pyramid has a vertex that is eccentrically positioned radially outward with respect to the insertion hole, has a height H greater than a lateral length W that is a short side of the bottom surface, and a length of the bottom surface. The height H is smaller than the vertical length L to be a side, and the horizontal length W of the bottom surface is configured to be larger than the adjacent interval F on the insertion hole side of the plurality of protrusions. Anti-vibration device characterized by The circumferential groove includes a first circumferential groove, and a second circumferential groove that is spaced apart from the first circumferential groove by a predetermined distance and is located on the upper surface side of the stopper body from the first circumferential groove,
The opening width C, which is the groove width in the openings of the first circumferential groove and the second circumferential groove, is made larger than the vertical length L of the bottom surface in the quadrangular pyramid shape,
The insertion hole extends from the lower surface of the stopper body to a position reaching the first circumferential groove, and extends from the terminal end of the first hole to the upper surface of the stopper body and tapers toward the upper surface of the stopper body. A second hole that expands into a shape,
2. The vibration isolator according to claim 1, wherein a thickness t <b> 2 of the constricted portion by the second circumferential groove is thinner than a thickness t <b> 1 of the constricted portion by the first circumferential groove.

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