JP2013194875A - Torsional damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torsional damper in a novel structure in which durability can be improved by preventing creased deformation when press-fitting an annular connecting rubber.SOLUTION: An end face 30 of an annular connecting rubber 16 in an axial direction before press-fitting includes an inner circumferential arcuate surface 32, an outer circumferential arcuate surface 34 and an intermediate arcuate surface 36, and all the arcuate surfaces 32, 34, 36 protrude outward. An inner circumferential intermediate surface 38 is provided for smoothly connecting the inner circumferential arcuate surface 32 and the intermediate arcuate surface 36, an outer circumferential intermediate surface 40 is provided for smoothly connecting the outer circumferential arcuate surface 34 and the intermediate arcuate surface 36, and these intermediate surfaces 38, 40 are made into plane or curved surface protruding outward. Respective curvature radiuses of the inner circumferential arcuate surface 32, the outer circumferential arcuate surface 34 and the intermediate arcuate surface 36 are made smaller than respective curvature radiuses of the inner circumferential intermediate surface 38 and the outer circumferential intermediate surface 40, and an outer end of the intermediate arcuate surface 36 in the axial direction is positioned outward in the axial direction with respect to the inner circumferential arcuate surface 32 and the outer circumferential arcuate surface 34.

Description

  The present invention relates to a torsional damper employed as a damper pulley for an automobile.

  Conventionally, a torsional damper applied to a damper pulley of an automobile is known. The torsional damper has a structure in which a disc-shaped hub and an annular mass member that is externally attached to the hub are elastically coupled by an annular coupling rubber interposed between the hub and the mass member in the radial direction. doing. For example, it is described in JP-A-2004-125108 (Patent Document 1).

  By the way, such a torsional damper is generally formed by pressing an annular connecting rubber into a gap provided between the hub and the mass member in the radial direction. The annular connecting rubber is disposed in a radially compressed state between the hub and the mass member in the radial direction, and is prevented from falling off.

  However, when the annular connecting rubber is pressed into the gap between the hub and the mass member in the radial direction and assembled, the inner peripheral surface of the annular connecting rubber is pressed against the hub, and the outer peripheral surface of the annular connecting rubber is the mass member. Pressed against. As a result, the press-fitting of the inner peripheral end portion and the outer peripheral end portion of the annular connecting rubber is delayed by the frictional resistance with respect to the press-fitting of the radially intermediate portion, and the radial intermediate portion of the end surface of the annular connecting rubber after press fitting There is a risk that wrinkles will occur, and there is a risk of problems in durability and reliability.

  In particular, if the thickness of the annular connecting rubber in the radial direction is increased for the purpose of improving the durability of the annular connecting rubber, wrinkles are likely to occur in the intermediate portion in the radial direction of the end face, resulting in a decrease in durability. It was easy to become.

JP 2004-125108 A

  The present invention has been made in the background of the above-described circumstances, and its solution is to prevent wrinkles from occurring in the intermediate portion in the radial direction during the press-fitting of the annular connecting rubber, and to realize improved durability. It is to provide a torsional damper having a novel structure.

  That is, according to the first aspect of the present invention, an annular mass member is extrapolated with respect to a disc-shaped hub, and an annular connecting rubber is press-fitted between the hub and the mass member. In the torsional damper in which the members are elastically connected by the annular connecting rubber, the inner peripheral end portion of the axial end surface of the annular connecting rubber before press-fitting is configured as an inner peripheral arc-shaped surface protruding outward. In addition, the outer peripheral end portion of the axial end surface of the annular coupling rubber is formed of an outer peripheral arc-shaped surface that protrudes outward, and the outer peripheral arc-shaped surface is formed outwardly between the inner peripheral arc-shaped surface and the outer peripheral arc-shaped surface. A convex intermediate arc-shaped surface is provided, and a curved surface that is flat or outwardly convex is formed between the inner peripheral arc-shaped surface and the intermediate arc-shaped surface on the axial end surface of the annular coupling rubber. The inner circumference gently connecting the inner arcuate surface and the intermediate arcuate surface An intermediate surface is provided, and between the outer peripheral arcuate surface and the intermediate arcuate surface on the axial end surface of the annular coupling rubber, a flat or outwardly curved curved surface is formed. An outer peripheral intermediate surface that gently connects the arc-shaped surface and the intermediate arc-shaped surface is provided, and the respective curvature radii of the inner peripheral arc-shaped surface, the outer peripheral arc-shaped surface, and the intermediate arc-shaped surface are The radius of curvature of each of the intermediate surface and the outer peripheral intermediate surface is smaller, and the axial outer end of the intermediate arc-shaped surface is the axial outer end of the inner peripheral arc-shaped surface and the axis of the outer peripheral arc-shaped surface. It is characterized by being located axially outward from any of the outer ends in the direction.

  According to the torsional damper described in the first aspect, when the annular connecting rubber is press-fitted between the hub and the mass member, the inner peripheral end and the outer peripheral end of the annular connecting rubber are not connected to the hub or the mass. It is possible to prevent wrinkle-like deformation from occurring on the end face in the axial direction of the annular connecting rubber due to the press-fitting after the intermediate portion due to the frictional resistance acting between the members. An intermediate arc shape in which the stress applied to the annular connecting rubber based on the frictional resistance is located axially outward from the inner circumferential arc surface and outer circumferential arc surface through the inner circumferential surface and outer circumferential surface. This is because the surface is transmitted so as to push the surface outward in the axial direction. As a result, even when, for example, the width dimension of the annular connecting rubber is increased, concentration of stress due to the formation of wrinkles is avoided, and the durability of the annular connecting rubber is improved.

  Moreover, the inner peripheral intermediate surface and the outer peripheral intermediate surface are formed with a larger radius of curvature than each arc-shaped surface, and the intermediate arc-shaped surface, the inner peripheral arc-shaped surface, and the outer peripheral arc-shaped surface are the inner peripheral intermediate surface and the outer peripheral intermediate surface. Through the surface, it is formed smoothly and continuously without having a concave portion (such as a concave folding point or a broken line on the outside). Therefore, local concentration of stress is avoided on the axial end surface of the annular connecting rubber, and the formation of wrinkles is suppressed, thereby improving durability.

  According to a second aspect of the present invention, in the torsional damper described in the first aspect, the axially outer end of the annular coupling rubber that is press-fitted is an outer peripheral end of the hub and an inner peripheral end of the mass member. With respect to the axial direction end surface in a part, it is located on the same plane thru | or an axial direction inner side.

  According to the second aspect, the axial dimension of the annular coupling rubber is set to be small, and the axial outer end of the annular coupling rubber is on the same plane as the axial end face of the hub or mass member or axially inward thereof. Even if it is located and restrained by a hub or mass member, the generation of wrinkles can be suppressed by the shape of the end face in the axial direction of the annular connecting rubber.

  According to a third aspect of the present invention, in the torsional damper described in the first or second aspect, the outer peripheral surface of the hub and the press-fitting surface of the annular connecting rubber on the inner peripheral surface of the mass member are both It is made into the cylindrical shape extended in an axial direction in the axial direction both ends.

  According to the third aspect, since the region compressed in the radial direction by the hub and the mass member in the annular connecting rubber is ensured with excellent space efficiency, the hub and the mass member are also axial in addition to the annular connecting rubber. The size can be reduced. Moreover, even if the shape of the end surface in the axial direction of the annular connecting rubber is devised, the end portion in the axial direction of the annular connecting rubber is constrained by the outer peripheral surface of the cylindrical hub and the inner peripheral surface of the mass member. The generation of wrinkles is prevented and durability is ensured.

  According to a fourth aspect of the present invention, in the torsional damper described in any one of the first to third aspects, the axially outer end of the intermediate arc-shaped surface in the annular connecting rubber before press-fitting is The outer circumferential arc-shaped surface protrudes outward in the axial direction with a size of 0.5 mm or more with respect to the axial outer end of the inner circumferential arc-shaped surface and the outer circumferential arc-shaped surface.

  According to the fourth aspect, the stress transmitted from the inner arcuate surface and the outer arcuate surface to the intermediate arcuate surface when the annular connecting rubber is press-fitted is effective in the direction of pushing the intermediate arcuate surface outward in the axial direction. Act on. Therefore, it is possible to advantageously prevent the formation of a concave wrinkle on the axial end surface of the annular connecting rubber, thereby realizing excellent durability.

  According to a fifth aspect of the present invention, in the torsional damper described in any one of the first to fourth aspects, the hardness of the annular connecting rubber is a type A durometer hardness test in accordance with JIS K 6253. And A60 or higher.

  According to the fifth aspect, since the annular coupling rubber is formed of a relatively hard rubber material, the annular coupling rubber is adopted by adopting the thick annular coupling rubber while maintaining the target vibration-proof characteristic. It becomes possible to ensure the durability of the rubber. Moreover, wrinkling during press-fitting, which can be a problem by increasing the hardness of the annular coupling rubber, is effectively prevented by devising the shape of the end face in the axial direction of the annular coupling rubber.

  According to a sixth aspect of the present invention, in the torsional damper described in any one of the first to fifth aspects, the annular connecting rubber is 30% or more in the radial direction between the hub and the mass member. Compressed at the compression rate.

  According to the sixth aspect, the annular connecting rubber is prevented from coming off in the axial direction by setting a large compression rate in the radial direction of the annular connecting rubber. In particular, even when a thick annular connecting rubber is used to improve the durability, it is possible to ensure a sufficient resistance against falling out. Moreover, the shape of the end face in the axial direction of the ring connecting rubber prevents the formation of wrinkles on the end face in the axial direction of the ring connecting rubber even when the ring connecting rubber is greatly compressed, thereby ensuring the durability of the ring connecting rubber. The

  According to the present invention, the end surfaces in the axial direction of the annular coupling rubber are the inner peripheral intermediate surface and the outer peripheral intermediate surface formed with a larger radius of curvature than the inner peripheral arc-shaped surface and the outer peripheral arc-shaped surface with respect to the intermediate arc-shaped surface. Are connected continuously. Further, the outer end of the intermediate arc-shaped surface is positioned axially outward from the outer end of the inner arc-shaped surface and the outer end of the outer-circular arc-shaped surface, so that the axial end surface of the annular connecting rubber is outward as a whole. It has a convex shape. Therefore, when the annular connecting rubber is press-fitted between the hub and the mass member, it is possible to prevent wrinkles from being generated on the axial end surface of the annular connecting rubber due to the elastic deformation of the annular connecting rubber due to frictional resistance. Thus, the durability of the annular connecting rubber is improved.

The rear view which shows the damper pulley as one Embodiment of this invention. II-II sectional drawing of FIG. Sectional drawing which shows the cyclic | annular connection rubber which comprises the damper pulley shown by FIG. The principal part expanded sectional view which expands and shows the principal part (A part) of FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show a damper pulley 10 for an automobile as an embodiment of a torsional damper having a structure according to the present invention. In the damper pulley 10, a substantially annular mass member 14 is externally inserted into a substantially disc-shaped hub 12, and an annular connecting rubber 16 is press-fitted between the hub 12 and the mass member 14 in the radial direction. The hub 12 and the mass member 14 are elastically connected by an annular connecting rubber 16. In the following description, the axial direction means the horizontal direction in FIG. 2 in principle.

  More specifically, the hub 12 is a highly rigid member formed of a metal material such as iron or aluminum alloy, and has a substantially disc shape. A circular hole 18 penetrating in the axial direction is formed in the central portion of the hub 12 so that a crankshaft of an internal combustion engine (not shown) can be inserted therethrough. Further, a cylindrical narrow pressure portion 20 that protrudes rearward in the axial direction is integrally formed at the outer peripheral end portion of the hub 12, and one axial end portion of the outer peripheral surface extends in the axial direction. In addition, the other end portion in the axial direction has a tapered shape with a diameter decreasing toward the outer side in the axial direction. On the other hand, a groove-like recess 22 that opens to the outer peripheral surface is formed in the central portion of the narrow pressure portion 20 in the axial direction. Further, a substantially cylindrical press-fitting surface extending in the axial direction is provided on both sides in the axial direction of the groove-like recess 22 on the outer peripheral surface of the narrow pressure portion 20. In addition, in the radial direction intermediate portion of the hub 12, four hollow holes 24 penetrating in the axial direction are formed, so that the weight of the hub 12 is reduced.

  A mass member 14 is extrapolated to the hub 12. The mass member 14 is a highly rigid member made of the same metal material as that of the hub 12 and has a substantially annular shape. Further, four V-shaped grooves 26 are formed at the outer peripheral end portion of the mass member 14 and open to the outer peripheral surface, respectively, so that the V-belt can be wound around. In addition, one end in the axial direction of the inner peripheral surface of the mass member 14 has a cylindrical shape that extends in the axial direction, and the other end in the axial direction has a tapered shape that increases in diameter outward in the axial direction. Yes. On the other hand, at the central portion of the mass member 14 in the axial direction, a protruding strip portion 28 that protrudes toward the inner peripheral side in a shape corresponding to the groove-shaped recess portion 22 is integrally formed. In addition, a substantially cylindrical press-fit surface extending in the axial direction is provided on both sides in the axial direction of the ridges 28 on the inner peripheral surface of the mass member 14.

  The hub 12 and the mass member 14 are arranged in a radially inserted state with a predetermined gap therebetween, and the annular coupling rubber 16 is inserted into the gap formed between the hub 12 and the mass member 14. Is press-fitted.

  As shown in FIG. 3, the annular coupling rubber 16 is a rubber elastic body that has a substantially constant cross-sectional shape and continuously extends in the circumferential direction, and has an inner peripheral surface and an outer peripheral surface that are substantially cylindrical surfaces. Yes. Further, the annular connecting rubber 16 has a width dimension D in a direction perpendicular to the axis of the cross section: D that is wider than a width dimension d of a gap formed between the hub 12 and the mass member 14. By being press-fitted between the narrow pressure portion 20 and the mass member 14, it is compressed in the radial direction. In the present embodiment, the radial distance d between the hub 12 and the mass member 14 is secured larger than that of the conventional damper pulley, and the durability is improved by increasing the rubber volume of the annular connecting rubber 16. Is planned.

  Further, the annular connecting rubber 16 has a hardness of A60 or higher, more preferably A65 or higher in a type A durometer hardness test in accordance with JIS K 6253. Thus, while ensuring a large width dimension D in the cross-section of the annular coupling rubber 16, a desired vibration isolation characteristic (a mass-spring resonance frequency using the mass member 14 as a mass and the annular coupling rubber 16 as a spring) is obtained. It can be realized.

  Further, the end surface in the axial direction of the annular connecting rubber 16 is a curved convex surface 30 that protrudes outward in the axial direction in a single state before press-fitting. More specifically, the curved convex surface 30 includes an inner circumferential arc-shaped surface 32 and an outer circumferential arc-shaped surface 34.

  The inner arcuate surface 32 and the outer arcuate surface 34 are arcuate curved surfaces that are convex outward and have substantially the same radius of curvature in the cross section shown in FIG. 32 is provided at the inner peripheral end of the axial end surface of the annular connecting rubber 16, and the outer peripheral arcuate surface 34 is provided at the outer peripheral end of the axial end surface of the annular connecting rubber 16.

  Further, an intermediate arcuate surface 36 is provided between the inner arcuate surface 32 and the outer arcuate surface 34. The intermediate arcuate surface 36 is an arcuate curved surface that protrudes outward in the axial direction in the cross section shown in FIG. 4. In the present embodiment, the intermediate arcuate surface 36 is provided at the center in the width direction of the annular coupling rubber 16. Yes. In the present embodiment, the radius of curvature of the intermediate arc-shaped surface 36 is larger than the radius of curvature of the inner circumferential arc-shaped surface 32 and the outer circumferential arc-shaped surface 34, but is not particularly limited. The radius of curvature of 36 may be the same as or smaller than the radius of curvature of the inner circumferential arc-shaped surface 32 and the radius of curvature of the outer circumferential arc-shaped surface 34.

  An inner peripheral intermediate surface 38 is provided between the intermediate arc-shaped surface 36 and the inner peripheral arc-shaped surface 32, and an outer peripheral intermediate surface 40 is provided between the intermediate arc-shaped surface 36 and the outer peripheral arc-shaped surface 34. ing. These inner peripheral intermediate surface 38 and outer peripheral intermediate surface 40 are both flat and are inclined outward in the axial direction toward the center in the width direction in the cross section of the annular connecting rubber 16 shown in FIG. In other words, the curvature radii of the inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40 are infinite, and the curvature radii of the inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40 are the inner peripheral arc-shaped surface 32 and the outer peripheral circle. The radius of curvature of the arcuate surface 34 and the radius of curvature of the intermediate arcuate surface 36 are made larger.

  The intermediate arc-shaped surface 36 and the inner peripheral arc-shaped surface 32 are connected so as to be smoothly continued by the inner peripheral intermediate surface 38, and the intermediate arc-shaped surface 36 and the outer peripheral arc-shaped surface 34 are connected by the outer peripheral intermediate surface 40. It is connected so that it is gently continuous. In this case, in the single annular connecting rubber 16, the inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40 are constituted by a plane inclined outward in the axial direction toward the boundary side with the intermediate arc-shaped surface 36, and the intermediate arc-shaped surface The outer end in the axial direction of 36 is located outward in the axial direction from the outer end in the axial direction of the inner arcuate surface 32 and the outer end of the outer arcuate surface 34 in the axial direction. In the annular connecting rubber 16 before press-fitting shown in FIG. 4, the outer end of the intermediate arcuate surface 36 is larger than the outer ends of the inner arcuate surface 32 and the outer arcuate surface 34 by 0.5 mm or more. In this embodiment, the distance between the outer end of the intermediate arcuate surface 36 and the outer ends of the inner arcuate surface 32 and the outer arcuate surface 34 is 0. It is 5 mm.

  The annular connecting rubber 16 having such an axial end face (curved convex surface 30) is press-fitted between the hub 12 and the mass member 14 in the radial direction, as shown in FIGS. Thereby, the annular connecting rubber 16 is compressed in the radial direction, and the annular connecting rubber 16 is held without being removed in the axial direction, and the hub 12 and the mass member 14 are elastically connected by the annular connecting rubber 16.

  Further, the outer end in the axial direction of the annular connecting rubber 16 (the outer end in the axial direction of the intermediate arcuate surface 36) is press-fitted between the hub 12 and the mass member 14 in the radial direction, and the outer end of the hub 12 and the mass. The member 14 is located on the same plane or inward in the axial direction without protruding outward in the axial direction with respect to the axial end surface at the inner peripheral end of the member 14. In the present embodiment, the outer end in the axial direction of the annular coupling rubber 16 is positioned on substantially the same plane with respect to the axial end surface of the outer peripheral end of the hub 12 and the axial end surface of the inner peripheral end of the mass member 14. doing.

  In addition, the annular connecting rubber 16 has a ratio (d / D) of less than 70% of the width dimension after press-fitting: d is a single width dimension: D, and the compression ratio ((D−d) / D). Is set to 30% or more, more preferably 40% or more. Thereby, the annular coupling rubber 16 is stably held between the radial directions of the hub 12 and the mass member 14, and the elastic coupling of the hub 12 and the mass member 14 by the annular coupling rubber 16 is maintained.

  Further, the annular connecting rubber 16 is convex on the inner peripheral side at a portion facing the groove-shaped concave portion 22 opened on the outer peripheral surface of the hub 12 and the protruding strip portion 28 formed to protrude on the inner peripheral surface of the mass member 14. It is bent and deformed. As a result, the bent portion of the annular connecting rubber 16 abuts in the axial direction against the groove-shaped concave portion 22 and the protruding strip portion 28, and the annular connecting rubber 16 is prevented from coming off in the axial direction.

  When the annular connecting rubber 16 of the present embodiment is press-fitted into the gap between the hub 12 and the mass member 14 having a narrow width, wrinkle-like deformation is prevented from occurring on the axial end surface opposite to the press-fitting direction. ing.

  That is, conventionally, when the annular coupling rubber is press-fitted between the hub 12 and the mass member 14, both ends in the width direction of the annular coupling rubber are intermediate due to frictional resistance acting between the hub 12 or the mass member 14. It is press-fitted later than the part. As a result, wrinkles may occur at the intermediate portion in the width direction on the axial end surface opposite to the press-fitting direction of the annular connecting rubber.

  Therefore, in the annular connecting rubber 16 of the present embodiment, the intermediate arcuate surface 36 is positioned axially outward from the inner arcuate surface 32 and the outer arcuate surface 34, and the intermediate arcuate surface 36 and The inner circumferential arc-shaped surface 32 or the outer circumferential arc-shaped surface 34 is provided so as to be smoothly continuous via the inner circumferential intermediate surface 38 and the outer circumferential intermediate surface 40 without having a recess. Thus, even if both ends in the width direction of the annular connecting rubber 16 are pressed into the intermediate portion with a delay due to frictional resistance at the time of press-fitting, both end portions in the width direction are lifted to the opposite side to the press-fitting direction as compared with the intermediate portion. As a result, the wrinkles generated by the above are reduced, and the durability of the annular connecting rubber 16 is improved. The stress acting on the both ends in the width direction of the annular connecting rubber 16 by the frictional resistance is formed in an intermediate arc shape from the inner peripheral arc-shaped surface 32 and the outer peripheral arc-shaped surface 34 through the inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40. This is because by transmitting the surface 36 so as to push it outward in the axial direction, concave deformation of the axial end surface of the annular connecting rubber 16 is prevented.

  The inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40 are formed with a larger radius of curvature than any of the intermediate arc-shaped surface 36, the inner peripheral arc-shaped surface 32, and the outer peripheral arc-shaped surface 34. As a result, the intermediate arc-shaped surface 36, the inner peripheral arc-shaped surface 32, and the outer peripheral arc-shaped surface 34 are gently connected via the inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40, and the curved convex surface 30 does not have a concave portion. The curved surface is convex outward as a whole. Therefore, the formation of wrinkles due to the action of stress on the curved convex surface 30 is prevented, and the durability of the annular connecting rubber 16 is ensured.

  Further, the axially outer end of the intermediate arcuate surface 36 is larger than the axially outer end of the inner circumferential arcuate surface 32 and the axially inner end of the outer circumferential arcuate surface 34 by 0.5 mm or more on the outer side in the axial direction. Now it is off. As a result, the inclination angle of the inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40 with respect to the direction perpendicular to the axis becomes sufficiently large, and the occurrence of wrinkles on the inner peripheral intermediate surface 38 and the outer peripheral intermediate surface 40 during press-fitting is avoided.

  In addition, since it is made difficult to generate wrinkles due to the shape of the curved convex surface 30, it is possible to form the annular connecting rubber 16 with a hard rubber material that is likely to generate wrinkles. While realizing the improvement, it is possible to prevent a change in the resonance frequency of the mass-spring system.

  Furthermore, even if the annular connecting rubber 16 is compressed and deformed with a large compression ratio of 30% or more between the radial direction of the hub 12 and the mass member 14, the shape of the curved convex surface 30 makes it difficult for wrinkles to occur. The annular connecting rubber 16 can be prevented from coming off while securing the rubber volume of 16 to improve the durability.

  In addition, the axial outer end of the annular coupling rubber 16 (intermediate arcuate surface 36) is both the axial end surface of the outer peripheral end of the hub 12 and the axial end surface of the inner peripheral end of the mass member 14. It is located on the same plane or on the inner side in the axial direction, and the axial dimension of the annular connecting rubber 16 is reduced. In particular, since the end face in the axial direction of the annular coupling rubber 16 is made to be a curved convex surface 30, wrinkles are less likely to occur, so that the entire annular coupling rubber 16 is disposed between the hub 12 and the mass member 14 and is annular. Even if radial compression is applied to the vicinity of the axial end portion of the connecting rubber 16, generation of wrinkles is prevented and durability is ensured.

  Further, even if the annular connecting rubber 16 is compressed between the hub 12 and the mass member 14 to the vicinity of the end in the axial direction, the generation of wrinkles is unlikely to be a problem, so the axial end is expanded outward in the axial direction. It is not necessary to reduce the amount of compression of the end portion in the axial direction of the annular connecting rubber 16 by, for example, adopting a shape to be formed. Therefore, the axial end of the press-fitting surface of the annular connecting rubber 16 on the outer peripheral surface of the hub 12 and the inner peripheral surface of the mass member 14 is formed into a cylindrical shape extending in the axial direction, so that the hub 12 and the mass member 14 of the annular connecting rubber 16 are It is possible to efficiently obtain a region compressed between the two. Thereby, the substantial axial direction length of the part which connects the hub 12 and the mass member 14 in the cyclic | annular connection rubber | gum 16 can be ensured largely.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the inner peripheral intermediate surface and the outer peripheral intermediate surface constituting the curved convex surface 30 of the annular connecting rubber 16 are not limited to flat surfaces, and may be curved surfaces convex outward. Even when the inner peripheral intermediate surface and the outer peripheral intermediate surface are curved surfaces, the radius of curvature of the inner peripheral intermediate surface and the outer peripheral intermediate surface is the intermediate arc-shaped surface 36, the inner peripheral arc-shaped surface 32, and the outer peripheral arc-shaped surface. It is made larger than each curvature radius of 34.

  Further, the intermediate arc-shaped surface 36 does not necessarily have to be provided at the center in the width direction, and may be provided so as to be biased to either one of the width direction (inner peripheral side or outer peripheral side). In that case, the inner peripheral intermediate surface and the outer peripheral intermediate surface have different shapes.

  In the above embodiment, an example is shown in which the present invention is applied to a damper pulley around which a V-belt is wound. However, the present invention is also suitably applied to, for example, a damper pulley around which a flat belt is wound. obtain.

10: damper pulley (torsional damper), 12: hub, 14: mass member, 16: annular coupling rubber, 30: curved convex surface (axial end surface of the annular coupling rubber), 32: inner circumferential arc surface, 34: outer circumferential circle Arc-shaped surface, 36: intermediate arc-shaped surface, 38: inner peripheral intermediate surface, 40: outer peripheral intermediate surface

Claims (6)

An annular mass member is extrapolated with respect to the disc-shaped hub, and an annular connecting rubber is press-fitted between the hub and the mass member, and the hub and the mass member are elastically connected by the annular connecting rubber. In the torsional damper
The inner peripheral end portion of the end surface in the axial direction of the annular connecting rubber before press-fitting is constituted by an inner peripheral arcuate surface convex outward, and the outer end portion of the end surface in the axial direction of the annular connecting rubber is outer. It is composed of an outer peripheral arc-shaped surface convex toward the direction, and an intermediate arc-shaped surface convex outward is provided between the inner arc-shaped surface and the outer arc-shaped surface.
Between the inner circumferential arc-shaped surface and the intermediate arc-shaped surface at the axial end surface of the annular connecting rubber, a flat or outwardly curved curved surface is formed, and the inner circumferential arc-shaped surface and the intermediate arc-shaped surface are formed. Between the outer peripheral arcuate surface and the intermediate arcuate surface on the axial end surface of the annular connecting rubber, and a curved surface convex outwardly. On the other hand, an outer peripheral intermediate surface that gently connects the outer peripheral arc-shaped surface and the intermediate arc-shaped surface is provided,
The curvature radii of the inner circumferential arc-shaped surface, the outer circumferential arc-shaped surface, and the intermediate arc-shaped surface are smaller than the curvature radii of the inner circumferential intermediate surface and the outer circumferential intermediate surface, respectively.
The axial outer end of the intermediate arcuate surface is located axially outward from both the axial outer end of the inner arcuate surface and the axial outer end of the outer arcuate surface. Torsional damper.   The axially outer end of the annular connecting rubber that is press-fitted is located on the same plane or axially inward with respect to the axial end surfaces of the outer peripheral end of the hub and the inner peripheral end of the mass member. The torsional damper according to claim 1.   3. The torsional assembly according to claim 1, wherein both the outer peripheral surface of the hub and the press-fitting surface of the annular connecting rubber on the inner peripheral surface of the mass member have a cylindrical shape extending in the axial direction at both end portions in the axial direction. damper.   The axial outer end of the intermediate arc-shaped surface of the annular connecting rubber before press-fitting is axially outer than the axial outer end of the inner arc-shaped surface and the outer axial end of the outer arc-shaped surface. The torsional damper according to any one of claims 1 to 3, wherein the torsional damper protrudes with a size of 0.5 mm or more.   The torsional damper according to any one of claims 1 to 4, wherein the hardness of the annular coupling rubber is set to A60 or more in a type A durometer hardness test in accordance with JIS K 6253.   The torsional damper according to claim 1, wherein the annular coupling rubber is compressed between the hub and the mass member in a radial direction at a compression rate of 30% or more.

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