JP2006010083A - Bumper spring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bumper spring capable of realizing nonlinear spring characteristic while securing superior durability, and surely restricting the stroke of a suspension mechanism. <P>SOLUTION: A bumper spring body 12 made out of a foamed elastic material is assembled in a holding cylindrical part 33 of a hard holding member 14, the bumper spring body 12 is projected outward from an opening part of the holding cylindrical part 33, and a stopper rubber 38 projected by height lower than the bumper spring body 12, is mounted on a tip end face of the holding cylindrical part 33. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bumper spring that is mounted on a suspension mechanism of a vehicle and elastically limits an operation amount of the suspension mechanism.

  For example, in an automobile suspension mechanism, the stroke amount of a wheel that is elastically supported so as to be displaceable with respect to the body is elastically limited, or between the suspension arms and the suspension to assist the elastic support function of the wheel by the suspension mechanism. A bumper spring made of an elastic material is mounted between the arm and the body either alone or in a state of being externally attached to the piston rod of the shock absorber. By the way, such a bumper spring is soft when the operation amount of the suspension mechanism is small and becomes hard when the operation amount is large in order to achieve both good riding comfort and steering stability of the vehicle. Non-linear spring characteristics that can be surely limited are required.

  Therefore, in order to realize such required characteristics, for example, a bumper spring main body having low spring characteristics is adopted, and a hard material formed of a resin material or the like on the outer peripheral surface of the intermediate portion in the axial direction of the bumper spring main body. Bumper springs have been proposed in which the restraining ring is externally fixed. In such a bumper spring, the bulging deformation of the bumper spring body is restricted by the restraining ring, and when the amount of compressive deformation of the bumper spring body increases, the restraining ring is brought into contact with another rigid member to be displaced. This makes it possible to restrict the amount of elastic deformation of the bumper spring body, and thus the amount of operation of the suspension mechanism, by raising the spring characteristics of the bumper spring body.

  However, in a bumper spring using such a restraining ring, since the bumper spring body is locally restricted by the restraining ring, the elastic deformation of the bumper spring body, particularly when the amount of elastic deformation becomes large. There is a problem that stress is easily concentrated on the restraining ring mounting portion, and it is difficult to sufficiently obtain the durability of the bumper spring body.

  In addition, if the contact of the restraining ring to the rigid member due to the input of a large load to the suspension mechanism is frequent or the contact force is excessive, the durability of the restraining ring or the rigid member is likely to be a problem. there were. If the restraining ring is broken, the elastic deformation amount of the bumper spring main body cannot be effectively limited, and the steering stability of the vehicle may be significantly reduced.

  Here, the present invention has been made in the background as described above, and the problem to be solved is to realize a non-linear spring characteristic while ensuring excellent durability, and a suspension mechanism. It is an object of the present invention to provide a bumper spring that can effectively and stably limit the amount of operation of the motor.

  According to the present invention made to solve such problems, bumper springs of the following modes can be obtained. It should be understood that the technical features and aspects of the present invention are not limited to those described below, but are recognized based on the description of the entire specification and the inventive concept described in the drawings. is there.

  A first aspect of the present invention is a bumper spring that is interposed between a pair of members that are relatively displaced in the approach / separation direction during operation of a vehicle suspension mechanism, and elastically limits an operation amount of the suspension mechanism. A bumper formed of a foamed elastic material with respect to a rigid holding member that forms a holding cylinder portion that opens from the one member toward the other member by being attached to one of the pair of members. The spring main body is held at the base end side thereof, and the front end side of the bumper spring main body is protruded from the holding cylinder portion toward the other member, and the other member is extended from the front end surface of the holding cylinder portion. A stopper rubber that protrudes with a protruding tip surface lower than that of the bumper spring body is provided toward the protruding tip surface of the bumper spring body. A bumper spring in which the bumper spring body is compressed and deformed in a state of being accommodated inside the stopper rubber by the contact of the other member, and the protruding tip surface of the stopper rubber contacts the other member. , Its characteristics.

  In such a bumper spring, while the input load is small, the stopper rubber does not abut against the other member, and the bumper spring body abuts against the other member and is compressed and deformed, thereby exhibiting the spring characteristics of the bumper spring body. Is done. When the input load increases, the amount of compressive deformation of the bumper spring body increases, the stopper rubber comes into contact with the other member, and both the bumper punling body and the stopper rubber are compressed and deformed. As a result, the spring characteristics are changed nonlinearly, and the hard spring characteristics are exhibited. Moreover, since the stopper rubber is provided on the distal end surface of the holding cylinder portion formed of a hard holding member, the relative displacement amount of the pair of members can be elastically and reliably limited, Thereby, the deformation amount of the bumper spring body is effectively limited, and good durability can be exhibited.

  Moreover, in such a bumper spring, since the bumper spring body is made of a foamed elastic body, the volume can be reduced during compression deformation to be compact, whereby the other member on the front end surface of the stopper rubber can be reduced. The contact can be stably realized without being obstructed by the bumper spring body. In addition, since the bumper spring body is housed inside the stopper rubber during compression deformation, interference with other members of the bumper spring body can be prevented.

  According to a second aspect of the present invention, in the bumper spring according to the first aspect, a holding rubber layer is formed on the inner peripheral surface of the holding cylinder portion of the holding member, and the inner surface of the holding rubber layer is formed. On the other hand, the outer peripheral surface of the bumper spring main body is fitted and held with an uneven locking structure that prevents the bumper spring body from coming out.

  In such a bumper spring according to the second aspect, the bumper spring main body can be firmly held by being fitted into the holding cylinder portion of the holding member. In particular, by forming the holding rubber layer, it becomes possible to easily form a recess, a projection or the like for holding the bumper spring body while simplifying the shape of the holding member and maintaining excellent manufacturability. . The bumper spring body does not necessarily have to be bonded to the holding member or the holding rubber layer. Further, the concave / convex locking structure can be realized by forming concave portions and convex portions having various shapes to be engaged with each other at corresponding portions of the holding rubber layer and the bumper spring main body. Furthermore, the holding rubber layer may be integrally formed with the stopper rubber.

  Further, a third aspect of the present invention is the bumper spring according to the first or second aspect, wherein the holding member is constituted by a bottomed cylindrical holding metal fitting, and by the bottom wall portion of the holding metal fitting, The end face on the base end side of the bumper spring main body is supported.

  In the bumper spring according to the third aspect, the base end portion of the bumper spring main body can be more firmly and stably held by the holding member. The holding metal fitting can be advantageously formed by, for example, drawing a metal plate, and preferably has an annular plate shape spreading outward in the radial direction with respect to the opening periphery. A flange-like portion is integrally formed, and a stopper rubber is formed to protrude from the flange-like portion. In this embodiment, for example, it is also effective to provide a bolt mounting hole in the bottom wall portion of the holding metal so that the holding metal can be attached to the suspension member or the like on the bottom wall.

  According to a fourth aspect of the present invention, in the bumper spring according to any one of the first to third aspects, the bumper spring main body has a hollow cylindrical shape having a center hole penetrating in the protruding direction. The end surface on the base end side of the bumper spring main body extends in the radial direction from the center hole to the outer peripheral edge, and further continuously extends in the axial direction on the outer peripheral surface on the base end side of the bumper spring main body. A concave groove that communicates the central hole of the spring body with the external space of the holding member is provided.

  In such a bumper spring according to the fourth aspect, the bumper spring can be mounted using the center hole of the bumper spring main body, and is attached to the piston rod of the shock absorber by extrapolation. It is also possible. Furthermore, the spring characteristics of the bumper spring body can be easily tuned by adjusting the size of the center hole. In addition, even when the front end surface of the bumper spring main body abuts against the other member and closes, the inner space of the center hole communicates with the outer space through the concave groove. When the volume changes, the supply and discharge of air through the concave groove is allowed, so that stable elastic deformation of the bumper spring main body is allowed, and the generation of abnormal noise such as air noise can be prevented. Moreover, by providing the central hole in the bumper spring body, the amount of bulging deformation toward the outer periphery during compression deformation can be suppressed, and interference with the stopper rubber or the like can be reduced or prevented. In addition, although a single ditch | groove may be sufficient, you may provide multiple.

  According to a fifth aspect of the present invention, in the bumper spring according to any one of the first to fourth aspects, the stopper rubber has a cylindrical shape that is continuous in the circumferential direction on the front end surface of the holding cylinder portion. It is formed.

  In such a bumper spring according to the fifth aspect, buckling deformation of the stopper rubber itself can be suppressed, and stable spring characteristics and excellent durability can be realized. Although it is effective to form the stopper rubber in a cylindrical shape in this way, it is of course possible to form it with a plurality of protruding block structures substantially independently in the circumferential direction. A stopper rubber having a gradually tapered shape as it goes to the projecting tip side, or a stopper rubber whose spring characteristics are adjusted by providing recesses on the inner and outer peripheral surfaces are also effective in obtaining a superior buffering action. Furthermore, it is also possible to integrally form a plurality of elastic protrusions spaced apart in the circumferential direction with respect to the protruding front end surface of the stopper rubber, so that the hitting sound when the stopper rubber contacts the other member And the impact can be reduced or prevented.

  According to a sixth aspect of the present invention, in the bumper spring according to any one of the first to fifth aspects, at least one circumferential groove extending in the circumferential direction on the outer circumferential surface with respect to the bumper spring body. It is formed.

  In such a bumper spring according to the sixth aspect, the compressive deformation in the protruding direction of the bumper spring main body is stabilized by the action of the circumferential groove, so that the desired spring characteristics can be obtained more stably. In addition, buckling deformation is prevented and durability can be further improved. In particular, by forming a plurality of circumferential grooves apart in the protruding direction, and further forming a central hole with respect to the bumper spring body, a circumferential groove extending in the circumferential direction on the inner circumferential surface of the bumper spring body The bumper spring is formed at a position different from the circumferential groove on the outer circumferential surface, more preferably, a plurality of circumferential grooves on the outer circumferential surface and circumferential grooves on the inner circumferential surface are alternately positioned in the protruding direction of the bumper spring body. By making the main body a bellows structure, more stable compression deformation can be realized.

  Furthermore, a seventh aspect of the present invention is the bumper spring according to any one of the first to sixth aspects, wherein the bumper spring main body has a protrusion height from the protrusion front end surface of the stopper rubber. It is characterized by being 75% or less of the total length of the spring body.

  In the bumper spring according to the seventh aspect, it is possible to further improve durability by avoiding excessive load input and excessive compressive deformation to the bumper spring body. Particularly preferably, the maximum compression strain of the bumper spring main body is set to 75% or less by the contact of the holding cylinder portion with the other member through the stopper rubber.

  Further, an eighth aspect of the present invention is the bumper spring according to any one of the first to seventh aspects, wherein the stopper rubber is formed of a non-foamed rubber material, and the spring constant of the stopper rubber is It is characterized by being set larger than the spring constant of the bumper spring body.

  In the bumper spring according to the eighth aspect, the non-linear target spring characteristic can be realized more advantageously. The material of the stopper rubber is not particularly limited, and is determined in consideration of the magnitude of the input load, the usage environment, etc. according to the required characteristics. Moreover, as a material of the bumper spring main body, any material can be used as long as it can cause compressive deformation accompanied by volume shrinkage. For example, foamed polyurethane or the like is preferably used.

  Furthermore, in the bumper spring according to the ninth aspect of the present invention, in the bumper spring according to any one of the first to eighth aspects, an outer peripheral surface is formed with respect to an intermediate portion in the protruding direction of the bumper spring body. An annular constraining ring extending in the circumferential direction is externally fitted.

  If such a constraining ring is provided, a non-linear spring characteristic is also realized in the bumper spring body itself, so that a non-linear spring characteristic can be realized more advantageously with respect to the bumper spring. In addition, since the elastic deformation of the bumper spring main body is restricted by the restraining ring, the shape at the time of compressive deformation can be stabilized, and more stable spring characteristics can be exhibited. However, when such a restraining ring is not attached to the bumper spring, problems such as stress concentration at the time of compressive deformation of the bumper pun ring can be avoided or reduced more advantageously, but even when the restraining ring is attached, In the present invention, since the amount of elastic deformation of the bumper spring main body is limited by the stopper rubber, excessive stress concentration is avoided and good durability can be realized. Note that it is more desirable that the restraining ring has a shape, a dimension, and the like so that contact with the stopper rubber and the holding member is avoided when the bumper spring body is compressed and deformed.

  In the bumper spring structured according to the present invention, a non-linear spring characteristic can be advantageously realized, and a soft spring characteristic is ensured in a region where the operation amount of the suspension mechanism is small, and the operation amount of the suspension mechanism is buffered. In addition, it can be surely limited.

  Hereinafter, in order to clarify the present invention more specifically, the bumper spring as the first to ninth common embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows a bumper spring 10 as a first embodiment of the present invention. The bumper spring 10 is configured by assembling a bumper spring main body 12 and a holding metal fitting 14 as a holding member.

  2 and 3, the bumper spring main body 12 has a thick, substantially cylindrical shape and includes a central hole 16 extending through the central axis. . Further, the end portion on one side in the axial direction (the lower side in FIG. 2) has a tip shape, and is a base end portion 18 having the largest outer diameter. On the other hand, the end portion on the other side in the axial direction has a tapered shape and is a tip portion 20 having the smallest outer diameter.

  In addition, on the outer peripheral surface of the bumper spring body 12, a first outer peripheral groove 22 and a second outer peripheral groove 24 that open to the outer peripheral surface and continuously extend in the circumferential direction are directed toward the outer peripheral side. And has a substantially V-shaped cross-section that is expanded. The first outer circumferential groove 22 and the second outer circumferential groove 24 are formed and spaced apart from each other in the axial direction at an intermediate portion in the axial direction of the bumper spring body 12. On the other hand, on the inner peripheral surface of the bumper spring main body 12, the first inner peripheral groove 26 and the second inner peripheral groove 28, which respectively open to the inner peripheral surface and extend continuously in the circumferential direction, It is formed with a substantially V-shaped cross section that expands toward the inner peripheral side. In the axial direction of the bumper spring main body 12, the first outer circumferential groove 22, the first inner circumferential groove 26, the second outer circumferential groove 24, and the second inner circumferential groove 28 are alternately positioned at a distance. As a result, the bumper spring body 12 has a substantially thick bellows structure as a whole except for the vicinity of the base end portion 18. Further, the bumper spring main body 12 is gradually thinned in the axial direction from the base end portion 18 toward the tip end portion 20, and the spring characteristic is made softer toward the tip end side.

  Furthermore, the base end portion 18 side of the bumper spring main body 12 has a large-diameter thick structure over a predetermined length in the axial direction. Further, a concave groove 30 that extends linearly in the radial direction and extends from the center hole 16 to the outer peripheral edge is formed on the end surface of the bumper spring body 12 on the base end portion 18 side. Any number of the concave grooves 30 may be formed, but in the present embodiment, a pair is formed on both sides of the center hole 16 in the radial direction. Further, after reaching the outer peripheral edge portion of the bumper spring main body 12, each concave groove 30 continuously extends on the outer peripheral surface of the bumper spring main body 12 in the axial direction, and opens into the first outer peripheral groove 22. is doing.

  By the way, such a bumper spring 10 is formed of a foamed elastic body. For example, urethane foam obtained by foaming polyurethane can be suitably used.

  On the other hand, the holding metal fitting 14 has a bottomed cylindrical shape as shown in FIGS. 4 and 5. And the attachment hole 34 is penetrated by the center of the bottom wall part 32, and the opening peripheral part of the cylinder wall part 33 is bent in the radial direction outward, and is the circumferential direction with substantially constant width | variety. A flange-like portion 36 that extends continuously is integrally formed.

  The holding metal member 14 may be formed of a hard material, and may be formed of, for example, a hard synthetic resin material. However, in the present embodiment, a metal plate such as an iron-based metal is subjected to press working or the like. What was obtained by drawing is used.

  In addition, a stopper rubber 38 is fixed to the holding metal fitting 14 in a mounted state on a flange-like portion 36 as a distal end surface of the cylindrical wall portion 33, thereby protruding outward in the axial direction. Is formed. The stopper rubber 38 has a cylindrical shape, and is bonded to the flange-shaped portion 36 so as to cover the flange-shaped portion 36 over substantially the entire surface. Note that a plurality of elastic protrusions 42 (eight in this embodiment) protruding in a substantially hemispherical shape are integrally formed on the protruding front end surface 40 of the stopper rubber 38 so as to be separated from each other in the circumferential direction.

  Furthermore, a holding rubber layer 44 is formed and fixed to the holding metal fitting 14 so as to cover the inner peripheral surface of the cylindrical wall portion 33. The holding rubber layer 44 is formed so as to cover the entire inner peripheral surface of the cylindrical wall portion 33 and is attached to the cylindrical wall portion 33. In particular, in this embodiment, the holding rubber layer 44 is integrally formed with the stopper rubber 38. More preferably, the holding metal fitting 14 is set in a mold for forming the holding rubber layer 44 and the stopper rubber 38, and the holding rubber layer 44 and the stopper rubber 38 are vulcanized and bonded to the holding metal fitting 14 simultaneously with the vulcanization molding. Thus, it is formed as an integrally vulcanized molded product.

  The holding rubber layer 44 is formed with a locking groove 46 that extends continuously in the circumferential direction at the bottom end of the holding fitting 14. The locking groove 46 has an inner peripheral surface shape corresponding to the outer peripheral surface shape of the base end portion 18 of the bumper spring main body 12. Thereby, as shown in FIG. 1, the base end portion 18 of the bumper spring main body 12 is pushed into the holding metal fitting 14, so that the outer peripheral portion of the base end portion 18 is locked into the locking groove of the holding rubber layer 44. 46 so as to be fitted. Then, the base end portion 18 of the bumper spring main body 12 is locked to the locking concave groove 46 of the holding rubber layer 44 in a state in which the bumper spring main body 12 can prevent the bumper spring main body 12 from coming out with an uneven locking structure. Is held by the holding metal fitting 14.

  Here, the axial length L1 of the bumper spring main body 12 is set to be larger than the protrusion height M1 of the stopper rubber 38 in the holding bracket 14, and L1> M1. Also, the length of the bumper spring body 12 in the axial direction: L1 The protrusion height of the stopper rubber 38 (including the elastic protrusions 42) of the holding bracket 14: The ratio of N1: The value of N1 / L1 is set to 0.25 or more. More preferably, the ratio of the axial length: P1 of the cylindrical wall portion 33 of the holding metal fitting 14 to the axial length: L1 of the bumper spring main body 12: P1 / L1 has a value of 0.25. Set as above. In particular, in the illustrated embodiment, the ratio of the protrusion height: M1 of the stopper rubber 38 to the axial length: L1 of the bumper spring body 12: M1 / L1 is set to approximately 0.4. Yes.

  The bumper spring 10 having such a structure is attached to one member 50 between a pair of members 50 and 52 that are relatively displaced in the approaching / separating direction when the suspension mechanism of the automobile is operated. . Such mounting is performed by, for example, a bolt 54 inserted through the mounting hole 34 of the bottom wall portion 32 of the holding metal fitting 14 as shown in the drawing. At this time, after the holding metal fitting 14 is fixed to the member 50 with the bolt 54, the bumper spring main body 12 can be fitted and assembled to the holding metal fitting 14, but in this embodiment, the bumper spring main body 12 is attached to the holding metal fitting. 14, the bolt 54 is screwed through the center hole 16 of the bumper spring main body 12, and the holding metal fitting 14 is screwed to the member 50.

  Under such a mounted state, the bumper spring 10 has the bumper spring main body 12 protruding from the one member 50 toward the other member 52, and the tip end portion 20 of the bumper spring main body 12 is in contact with the other member 52. To be opposed to each other. The bumper spring body 12 is positioned and mounted so that the central axis thereof is in the direction of approaching / separating the members 50 and 52. In this state, when the two members 50 and 52 are relatively brought close to each other by the operation of the suspension mechanism, the other member 52 first contacts the bumper spring main body 12. As a result, the bumper spring body 12 is compressed and deformed in the axial direction. At that time, since the stopper rubber 38 does not contact the other member 52, a soft spring characteristic is exhibited based on the compression spring of the bumper spring body 12 alone. Further, when the operation amount of the suspension mechanism increases and the amount of compressive deformation of the bumper spring main body 12 increases, not only the bumper spring main body 12 but also the stopper rubber 38 comes into contact with the other member 52. As a result, the compression springs of both the bumper spring main body 12 and the stopper rubber 38 act, the spring constant increases rapidly, and a hard spring characteristic is exhibited.

  Therefore, according to the bumper spring 10 of the present embodiment, the soft spring characteristic is exhibited while the operation amount of the suspension mechanism is small, and when the operation amount of the suspension mechanism is increased, the spring characteristic is rapidly increased, and the suspension An excessive operation amount of the mechanism, in other words, an excessive displacement of the vehicle body in the rolling direction can be reliably prevented. Thereby, an improvement in steering stability can be advantageously achieved while ensuring an excellent ride comfort during normal driving.

  Further, the bumper spring body 12 and the stopper rubber 38 can share the buffer function required for the bumper spring 10. As a result, the spring characteristics of the bumper spring body 12 are softened to assist the elastic support function of the wheels by the suspension mechanism and to limit the operation amount of the suspension mechanism within a range in which the riding comfort during normal driving can be ensured. It is possible to realize a buffering initial operation of the stopper function, and to make the operation amount of the suspension mechanism bufferable and reliable without increasing the protruding height of the stopper rubber 38 to the extent that buckling or the like becomes a problem. The limiting stopper function can be advantageously realized. In particular, since the stopper rubber 38 is formed on the cylindrical wall portion 33 of the holding metal member 14 made of a hard material, the relative displacement amount of both the members 50 and 52 is substantially ensured by the cylindrical wall portion 33. It can be limited to.

  In particular, in this embodiment, since the stopper rubber 38 has a cylindrical shape continuous in the circumferential direction, irregular deformation such as buckling can be more advantageously prevented. Further, since the elastic protrusion 42 is formed on the protruding front end surface 40 of the stopper rubber 38, the hitting sound when the stopper rubber 38 strikes the member 52 is reduced, and the stopper rubber 38 is applied to the member 52. At the time of contact, a reduction effect such as a feeling of a dullness felt by a person riding in a car is also exhibited.

  Further, the bumper spring body 12 is formed of a foamed elastic body, and its volume is reduced during compression. Therefore, irregular deformation such as buckling is advantageously prevented, and compression deformation can be stably performed in the axial direction. . Since the bumper spring body 12 is reduced in volume so as to be accommodated in the stopper rubber 38 and the holding bracket 14 as the amount of compressive deformation increases, the bumper spring body 12 protrudes outward in the radial direction. Thus, neither the other member is buffered nor the contact of the stopper rubber 38 with the member 52 is hindered. In particular, in this embodiment, since the center hole 16 is formed in the bumper spring main body 12 and the bulging deformation to the inner peripheral side is allowed, the bulging deformation to the outer peripheral side in the bumper spring main body 12 is further increased. It can advantageously be reduced or prevented.

  In the present embodiment, since a restraining ring or the like is not attached to the bumper spring main body 12, local stress concentration during compression deformation of the bumper spring main body 12 can be advantageously avoided. Moreover, the amount of compressive deformation of the bumper spring main body 12 can be reliably limited by the action of limiting the operation amount of the suspension mechanism by the contact of the cylindrical wall portion 33 of the holding metal fitting 14 and the stopper rubber 38 with the member 52. The maximum generated stress of the bumper spring main body 12 is also suppressed within the limit, and excellent durability can be exhibited.

  Further, the central hole 16 of the bumper spring main body 12 passes between the inner surface of the bottom wall portion 32 of the holding metal fitting 14 and the inner peripheral surface of the holding rubber layer 44 through the concave groove 30 of the bumper spring main body 12. The opening is always maintained in communication with the external space, and air supply / exhaust between the central hole 16 of the bumper spring body 12 and the external space is allowed. Accordingly, even when the member 52 is in contact with the tip 20 of the bumper spring body 12 and the tip opening of the center hole 16 is covered, the volume of the center hole 16 is also deformed when the bumper spring body 12 is elastically deformed. The change is easily allowed to avoid damage to the bumper spring main body 12 due to an increase in pressure in the center hole 16, and the desired spring characteristics can be stably exhibited. Generation of abnormal noise can be effectively prevented.

  As described above, the bumper spring 10 as one embodiment of the present invention has been described in detail. However, this is merely an example, and the aspect of the present invention is not limited to the specific description in the embodiment. .

  In particular, the specific material, shape, size, and the like of the bumper spring main body and the stopper rubber are appropriately determined according to required characteristics and the like, and are not limited. An example of a form different from the above embodiment is shown in FIG. 6 as a second embodiment. In the present embodiment, in order to facilitate the understanding, the same reference numerals as those in the first embodiment are assigned to the members corresponding to those in the first embodiment in the drawing. And

  That is, the bumper spring main body 12 constituting the bumper spring 60 of the present embodiment has a thick cylindrical shape as a whole as shown in FIGS. The portion 20 has a slightly larger diameter, and the proximal end portion 18 has a slightly larger diameter than the distal end portion 20. Further, first and second outer peripheral grooves 22 and 24 are formed on the outer peripheral surface so as to be spaced apart from each other in the axial direction, and the first inner peripheral groove 26 is formed on the inner peripheral surface of the distal end portion 20. The axial spring characteristics are softly adjusted. Furthermore, on the outer peripheral surface of the base end portion 18, an annular locking groove 62 that extends continuously in the circumferential direction is formed.

  On the other hand, as shown in FIGS. 9 and 10, the holding metal fitting 14 constituting the bumper spring 60 of the present embodiment has its cylindrical wall portion 33 slightly narrowed toward the opening side, It is made into the cylindrical shape with the reverse taper in which the opening part was reduced in diameter from the bottom part. Thereby, the width of the flange-like part 36 can be set large while suppressing the outer diameter of the flange-like part 36.

  Further, the holding rubber layer 44 attached to the inner peripheral surface of the holding metal fitting 14 is integrally formed with a locking protrusion 64 that continuously extends in the circumferential direction on the inner peripheral surface. Then, as shown in FIG. 1, by engaging the bumper spring main body 12 with the holding metal fitting 14, the locking protrusion 64 of the holding rubber layer 44 with respect to the locking groove 62 of the bumper spring main body 12. The bumper spring main body 12 is locked to the holding metal fitting 14. In short, in this embodiment, the concave / convex locking structure that prevents the bumper spring body 12 from coming out of the holding fitting 14 is configured by the locking concave grooves 62 and the locking ridges 64.

  Further, the stopper rubber 38 formed to protrude on the flange-like portion 36 of the holding metal fitting 14 is formed with a protruding height larger than that of the first embodiment, and the inner diameter dimension is increased toward the tip end side. Thus, it has a cross-sectional shape that becomes thinner toward the tip side. Further, groove-like recesses 66 and 68 extending in the circumferential direction are formed on the inner and outer peripheral surfaces of the stopper rubber 38, and the compression spring characteristics in the axial direction of the stopper rubber 38 are adjusted. Furthermore, the protrusion tip surface 40 of the stopper rubber 38 is formed with recesses 70 and protrusions 72 alternately in the circumferential direction, and a substantially truncated cone in the center of each recess 70 toward the protrusion direction of the stopper rubber 38. The spherical protrusions 42 having a spherical shape and projecting with a shape are integrally formed. The protrusion height of the elastic protrusion 42 is larger than the step size of the concave portion 70 and the convex portion 72, and the tip portion of the elastic protrusion 42 is protruded outward in the axial direction from the convex portion 72. .

  Even in the bumper spring 60 having such a structure, the same effects as those of the bumper spring 10 of the first embodiment can be effectively exhibited. In particular, in the bumper spring 60 of the present embodiment, the outer periphery of the bumper spring main body 12 is surrounded by the cylindrical wall portion 33 of the holding metal fitting 14 and the stopper rubber 38 in a portion that is more than half of the axial length. Therefore, buckling deformation of the bumper spring main body 12 and local deformation to the outside are further advantageously prevented, so that more stable compression deformation is caused. Further, the bumper spring main body 12 is thicker than that of the first embodiment, and the protruding height of the stopper rubber 38 is increased, so that both members constituting the suspension mechanism are The sudden rise of the spring characteristic accompanying the increase in the relative displacement amount in the approaching direction is alleviated, and a smooth buffer effect can be exhibited. In particular, in the present embodiment, the concave portion 70 and the convex portion 72 are formed on the protruding front end surface 40 of the stopper rubber 38, and the elastic protrusion 42 larger than that of the first embodiment is formed. In the transition region from the soft spring characteristic based on the compression deformation of the spring body 12 to the hard spring characteristic based on the compression deformation of the stopper rubber 38, there is an advantage that the shocking change of the spring characteristic can be advantageously alleviated.

  In both the first and second embodiments, the cylindrical bumper spring main body 12 is employed. However, in the present invention, the bumper spring main body can be a solid structure. . In this case, for example, a female screw portion such as a nut is fixed to the holding metal fitting 14 so that the bolt can be fixed to the member 50, or the holding metal piece 14 is welded to the member 50, It is effective to attach the holding metal fitting 14 to the member 50 by, for example, forming a mounting leg portion protruding on the surface.

  Further, when the central hole is not formed in the bumper spring body, it is not necessary to form the air vent hole by the concave groove 30 or the like.

  Furthermore, even when the central hole is formed in the bumper spring main body, instead of forming the concave groove in the bumper spring main body, the concave groove is formed on the surface of the holding metal fitting or holding rubber layer to which the bumper spring main body is fitted. It is also possible to form an air vent hole between the outer peripheral surface of the bumper stopper body.

  It is also possible to form the stopper rubber with a foamed elastic material.

  In addition, when the cylindrical wall part in a holding | maintenance metal fitting is thick and the width dimension of the front end surface of a cylindrical wall part can fully be ensured, a flange-shaped part etc. do not necessarily need to provide.

  In addition, although not enumerated one by one, the present invention can be implemented in a mode to which various changes, modifications, improvements, and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the gist of the present invention.

It is a longitudinal cross-sectional view which shows the bumper spring as 1st embodiment of this invention, Comprising: It is a figure shown by the cross section corresponding to the II-II cross section in FIG. It is a longitudinal cross-sectional view which shows the bumper spring main body which comprises the bumper spring shown by FIG. 1, Comprising: It is a figure equivalent to the II-II cross section in FIG. FIG. 3 is a bottom view of the bumper spring main body shown in FIG. 2. It is a longitudinal cross-sectional view which shows the holding metal fitting which comprises the bumper spring shown by FIG. 1, Comprising: It is a figure corresponded in the IV-IV cross section in FIG. It is a top view of the holding metal fitting shown by FIG. It is a longitudinal cross-sectional view which shows the bumper spring as 2nd embodiment of this invention, Comprising: It is a figure shown by the cross section corresponding to the VII-VII cross section in FIG. It is a longitudinal cross-sectional view which shows the bumper spring main body which comprises the bumper spring shown by FIG. 6, Comprising: It is a figure corresponded in the VII-VII cross section in FIG. FIG. 8 is a bottom view of the bumper spring main body shown in FIG. 7. It is a longitudinal cross-sectional view which shows the holding metal fitting which comprises the bumper spring shown by FIG. 6, Comprising: It is a figure corresponded in the IX-IX cross section in FIG. FIG. 10 is a plan view of the holding metal fitting shown in FIG. 9.

Explanation of symbols

10, 60 Bumper spring 12 Bumper spring main body 14 Holding bracket 38 Stopper rubber 44 Holding rubber layer

Claims (6)

A bumper spring that is interposed between a pair of members that are relatively displaced in the approach / separation direction during operation of the vehicle suspension mechanism and elastically limits an operation amount of the suspension mechanism;
A bumper spring formed of a foamed elastic material with respect to a hard holding member that forms a holding cylinder portion that opens from the one member toward the other member by being attached to one of the pair of members. The main body is held at the base end side, and the front end side of the bumper spring main body is projected from the holding cylinder portion toward the other member, and from the front end surface of the holding cylinder portion to the other member. A stopper rubber that protrudes with a protruding front end surface lower than that of the bumper spring body is provided, and the bumper spring main body is placed inside the stopper rubber by contact of the other member with the protruding front end face of the bumper spring main body. A bumper spring that is compressed and deformed in the accommodated state so that the protruding tip surface of the stopper rubber contacts the other member   A holding rubber layer is formed on the inner peripheral surface of the holding cylinder portion of the holding member, and the outer peripheral surface of the bumper spring body is fitted to the inner peripheral surface of the holding rubber layer with an uneven locking structure that prevents the bumper spring body from coming out. The bumper spring according to claim 1, which is held together.   3. The bumper spring according to claim 1, wherein the holding member is configured by a bottomed cylindrical holding metal fitting, and a base wall side end surface of the bumper spring body is supported by a bottom wall portion of the holding metal fitting.   The bumper spring body has a hollow cylindrical shape having a center hole penetrating in the protruding direction, and extends radially from the center hole to the outer peripheral edge at the proximal end surface of the bumper spring body. And a concave groove that extends in the axial direction on the outer peripheral surface of the base end side of the bumper spring body and communicates the central hole of the bumper spring body with the external space of the holding member. The bumper spring described in 1.   The bumper spring according to any one of claims 1 to 4, wherein the stopper rubber is formed in a cylindrical shape continuous in a circumferential direction on a front end surface of the holding cylinder portion. The bumper spring according to any one of claims 1 to 5, wherein at least one circumferential groove extending in the circumferential direction on an outer peripheral surface is formed on the bumper spring body.

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