JP2009127822A - Cylindrical dynamic damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel cylindrical dynamic damper capable of stably providing a vibration damping effect and of effectively providing a vibration damping effect against vibrations in a wide frequency range by reducing the temperature dependency and the amplitude dependency. <P>SOLUTION: Cylindrical metallic springs 14 each having a tapered cylindrical part 18 are so disposed as to be gradually reduced in diameter from each axial end of a cylindrical mass member 12 toward the axial outside. The small diameter end part of the cylindrical metallic spring 14 is formed in a rotating shaft fixing part 22 secured onto a rotating shaft 16. The cylindrical mass member 12 is radially stacked on each other through a contact rubber elastic body 32 at the large diameter end part of each cylindrical metallic spring 14, and so supported as to be displaced relative to each other. While the cylindrical mass member 12 elastically supported by the cylindrical metallic springs 14 by at least a radial input of vibration, the cylindrical mass member 12 is sprung from the cylindrical metallic springs 14 and radially displaced relative to each other, and repeatedly hits the spring through the contact rubber elastic body 32. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a cylindrical mass member is extrapolated to a rotation shaft as a main vibration system and elastically supported via an elastic member, thereby constituting a sub vibration system for the rotation shaft to be damped. The present invention relates to a cylindrical dynamic damper.

  2. Description of the Related Art Conventionally, a cylindrical dynamic damper (dynamic vibration absorber) is known as a type of vibration damping device that is attached to a rotating shaft such as a drive shaft or propeller shaft of an automobile to absorb and suppress the vibration. . In general, a cylindrical dynamic damper is configured such that a cylindrical damper mass is extrapolated at a predetermined distance to the outer peripheral side of a rotary shaft, and the damper mass is rotated by a rubber elastic body interposed between the damper mass and the rotary shaft. It is made into the structure elastically connected and supported by. As a result, a vibration system composed of one mass-spring system is configured, and this one vibration system functions as a sub-vibration system with respect to the rotating shaft that is the main vibration system, thereby reducing the vibration reduction effect that is a dynamic damper effect. Is demonstrated. For example, those disclosed in Patent Document 1 (Japanese Patent Publication No. 07-47979), Patent Document 2 (Japanese Patent Laid-Open No. 2000-199542), and the like.

  However, in the cylindrical dynamic damper having the conventional structure as described above, there is a problem that the dynamic damper effect cannot be effectively exhibited only in a relatively narrow frequency range tuned by the secondary vibration system. Further, since the temperature dependency and amplitude dependency of the rubber elastic body are high, the tuning frequency may change due to changes in the environment and input vibration. In particular, dynamic dampers mounted on automobiles may be exposed to temperature changes of ± 50 ° C or higher depending on the environment, running conditions, internal combustion engine, etc. is there. As a result, there has been a problem that the required damping effect is difficult to be exhibited stably.

  In order to deal with the above-mentioned problems, for example, thorough production management of dynamic dampers or a plurality of dynamic dampers with different tunings may be adopted. There is a limit, and the use of multiple dynamic dampers has a problem that an increase in cost and weight is inevitable.

Japanese Patent Publication No. 07-47979 JP 2000-199542 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that temperature dependency and amplitude dependency are reduced, and a vibration damping effect is stably obtained. It is another object of the present invention to provide a cylindrical dynamic damper having a novel structure capable of effectively obtaining a damping effect against vibrations in a wide frequency range.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

  That is, a feature of the present invention is that a cylindrical dynamic damper that is attached to the rotating shaft in an extrapolated state and suppresses vibration to be damped of the rotating shaft has a cylindrical shape having an inner diameter larger than the outer diameter of the rotating shaft. Using a mass member and a pair of cylindrical metal springs having a tapered cylindrical portion at an axially intermediate portion, each cylindrical metal spring gradually decreases in diameter toward the axially outer side from both axial end portions of the cylindrical mass member. The end portion of each cylindrical metal spring is arranged as a rotating shaft fixing portion that is fitted and fixed to the rotating shaft, while the cylindrical end portion of each cylindrical metal spring has a cylindrical shape. The mass member is overlapped in the radial direction via the abutting rubber elastic body and supported so as to be relatively displaceable. At least in the resonance state of the cylindrical mass member elastically supported by the cylindrical metal spring by the radial vibration input The shape mass member jumps from the cylindrical metal spring to the radial direction In cylindrical dynamic damper which is adapted impinges repeatedly through the relative displacement to the contact rubber elastic body.

  In the cylindrical dynamic damper having the structure according to the present invention, the secondary vibration system with respect to the rotation shaft as the main vibration system has a cylindrical mass member as a mass component and a pair of cylindrical metal springs. It consists of a mass-spring system as a spring component. That is, since the spring component is composed of a metal spring, the adverse effect on the vibration damping effect due to temperature dependency and amplitude dependency is reduced or avoided as compared with the case where the spring component is composed of a rubber member.

  Moreover, the damper of the rotating shaft is based on the fact that the cylindrical mass member jumps from the cylindrical metal spring under the resonance state of the cylindrical mass member and is relatively displaced in the radial direction and repeatedly hits through the contact rubber elastic body. The peak vibration newly generated in the frequency range on both the upper and lower sides (low frequency side and high frequency side) of the frequency range of the peak vibration before mounting is reduced at the time of mounting. That is, at the tuning frequency of the secondary vibration system, the vibration amplitude of the main vibration system tends to increase in the frequency range on both sides outside the tuning frequency instead of suppressing the vibration amplitude of the main vibration system. On the other hand, the cylindrical mass member of the present invention has an independent structure from the cylindrical metal spring. When the amplitude increases, the cylindrical mass member jumps from the cylindrical metal spring and repeats the hit. Therefore, when the vibration amplitude of the main vibration system increases in the opposite frequency range outside the tuning frequency in the secondary vibration system, and the input vibration to the secondary vibration system increases, the cylindrical mass member jumps and strikes. The vibration control effect by will be exhibited effectively. As a result, the tuning frequency of the secondary vibration system effectively suppresses the vibration of the main vibration system based on the damping effect of the dynamic damper function of the secondary vibration system, and both side frequencies that deviate from the tuning frequency of the secondary vibration system. In the region, the damping effect on the main vibration system is effectively exhibited based on the hit of the cylindrical mass member. In addition, the dynamic damper function and the vibration damping function by hitting cooperate, and an effective vibration reduction effect can be exhibited over a wide frequency range with respect to vibration in the main vibration system.

  Therefore, in the rotating shaft equipped with the cylindrical dynamic damper according to the present invention, the vibration level is reduced over a wide frequency range, and the object is based on small temperature dependency and amplitude dependency. The vibration control effect can be obtained stably.

  Further, in the dynamic damper according to the present invention, in the pair of cylindrical metal springs, a structure is employed in which at least one slit extending from the rotating shaft fixing portion to the tapered cylindrical portion is formed on the circumference. Also good. According to such a structure, when the rotary shaft fixing portion composed of the end portion on the small diameter side is externally fitted to the rotary shaft, the diameter expansion deformation of the rotary shaft fixing portion is largely allowed by the slit. As a result, the cylindrical dynamic damper with the cylindrical metal spring can be easily mounted on the rotating shaft, and the large-diameter portion of the rotating shaft having a larger outer diameter than the mounting portion of the cylindrical dynamic damper is the rotating shaft. Even if it is provided at the end of this, it is possible to easily get over the large-diameter portion by mounting the rotating shaft fixing portion with a larger diameter.

  Further, the spring characteristics can be tuned and changed by using a slit formed in the cylindrical metal spring. That is, based on the design change such as the size, shape, number, and arrangement of the slits, it is possible to secure a large degree of freedom in tuning the characteristics of the spring system of the cylindrical dynamic damper and the natural frequency of the cylindrical dynamic damper.

  Furthermore, in the above-described cylindrical dynamic damper according to the present invention, a structure in which the slits are formed unevenly on the circumference of the cylindrical metal spring is suitably employed. Here, the slits are formed unevenly on the circumference of the cylindrical metal spring. In addition to the width, length, and shape of the plurality of slits, the intervals between the slits are different in the circumferential direction. And various other aspects. Thereby, in a cylindrical metal spring, mutually different spring characteristics can be imparted in different axis-perpendicular directions. As a result, a plurality of natural tuning frequencies in the direction perpendicular to the axis of the cylindrical dynamic damper can be set in different directions. In addition, since the dynamic damper rotates together with the rotating shaft, as a result, an effective vibration damping effect is exhibited in a wide frequency range as a whole by connecting a plurality of tuning frequency ranges.

  In the cylindrical dynamic damper according to the present invention, a structure in which a damping member that is sheared and deformed in accordance with elastic deformation of the pair of cylindrical metal springs when vibration is input in a direction perpendicular to the axis may be employed. Thereby, since a large damping force can be obtained by utilizing the shear deformation of the damping member, the vibration damping effect can be further improved. In addition, since the damping member undergoes shear deformation at the time of vibration input in the direction perpendicular to the axis, the elasticity due to the compression deformation of the damping member is sufficiently reduced, so that the main spring characteristics are effectively exhibited by the pair of cylindrical metal springs. The That is, the spring action by the damping member is suppressed, and the adverse effect on the damping effect due to the relatively large temperature dependency and amplitude dependency of the damping member is reduced or avoided.

  For the damping member, for example, rubber materials such as natural rubber, styrene / butadiene rubber, butyl rubber and urethane rubber, resin materials such as polystyrene, polyester, polyvinyl chloride and thermoplastic elastomer, mica and carbon black, etc. Various damping materials obtained by adding the above fillers are employed. Preferably, the damping member includes a high damping material such as a high damping rubber such as butyl rubber, a styrenic thermoplastic elastomer, and a polymer gel such as hydrogel or organogel.

  Furthermore, the above-described cylindrical dynamic damper according to the present invention employs a structure in which the damping member is configured by fixing the damping material made of a polymer material so as to cover the surface of the cylindrical metal spring. Also good. According to this, the space for forming the damping member in the dynamic damper is reduced, and compactness is achieved. Further, by protecting the cylindrical metal spring with the damping member, it is possible to improve the durability and corrosion resistance of the spring.

  Further, in the cylindrical dynamic damper according to the present invention, the pair of cylindrical metal springs are independent from each other, and both end portions in the axial direction of the cylindrical mass member are connected to the respective large diameter side end portions of the pair of cylindrical metal springs. Alternatively, a structure may be employed in which a radial striking portion of the cylindrical mass member is configured to be opposed to each other in the radial direction. According to such a structure, a large area of the contact portion of the cylindrical mass member with respect to the cylindrical metal spring is ensured, so that the vibration damping effect and the sound reduction effect can be freely adjusted based on the design change of the contact portion. The degree can be improved.

  Further, in the cylindrical dynamic damper according to the present invention, a structure is employed in which a cover sleeve is provided on the outer peripheral side of the cylindrical mass member so as to extend in the axial direction across a pair of cylindrical metal springs. Also good. This prevents entry of foreign matter such as water, oil, and dust between the opposed surfaces of the cylindrical mass member and the cylindrical metal spring, thereby further stabilizing the desired vibration damping effect.

  In the cylindrical dynamic damper according to the present invention, a structure in which an annular seal that protrudes inward in the radial direction and extends in the circumferential direction is formed in the opening portion on the small diameter side of the pair of cylindrical metal springs. May be. According to such a structure, when the cylindrical dynamic damper is mounted on the rotating shaft, the sealing performance between the mounting surfaces is improved by the annular seal interposed between the mounting surfaces by being compressed and deformed. . Therefore, foreign matter such as water and oil can be prevented from entering the inside of the cylindrical dynamic damper, and desired characteristics can be advantageously ensured. Note that it is preferable that the annular seal is integrally formed with the damping member in consideration of the manufacturing cost and the reduction in the number of parts.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described. First, FIGS. 1 and 2 show an automobile dynamic damper 10 as a first embodiment according to a dynamic vibration absorber as a cylindrical dynamic damper of the present invention. The automotive dynamic damper 10 has a cylindrical shape as a whole, and a cylindrical mass member 12 as a cylindrical mass member is arranged at the axial central portion, and on both axial sides sandwiching the cylindrical mass member 12. A cylindrical leaf spring 14 as a cylindrical metal spring is provided. The automobile dynamic damper 10 according to the present embodiment is mounted on a circular rod-shaped drive shaft 16 as a rotating shaft that constitutes a front axle of an FF vehicle, a rear axle of an FR vehicle, a front and rear axle of a 4WD vehicle, and the like. (See FIG. 3). In the following description, the axial direction of the dynamic damper 10 and the drive shaft 16 refers to the left-right direction in FIGS.

  Specifically, the cylindrical mass metal fitting 12 has a thick cylindrical shape extending in an axial direction with a substantially constant circular cross section, and is formed of an iron-based metal material having a large specific gravity. The inner diameter dimension d1 of the cylindrical mass fitting 12 is larger than the maximum outer diameter dimension of the drive shaft 16.

  On the other hand, the cylindrical leaf spring 14 is an elastic member formed of a metal material such as spring steel, and has a cylindrical shape as a whole. Here, an intermediate portion in the axial direction of the cylindrical leaf spring 14 is a tapered cylindrical portion 18 whose diameter dimension gradually decreases from one axial direction to the other. A mass support portion 20 extending straight in the axial direction and a shaft fixing portion 22 as a rotating shaft fixing portion are integrally formed at the large-diameter side end portion and the small-diameter side end portion of the tapered cylindrical portion 18, respectively.

  In particular, between the tapered cylindrical portion 18 and the mass support portion 20, an annular plate portion 24 that extends in an annular shape in the direction perpendicular to the axis is integrally formed, and the outer peripheral edge portion of the annular plate portion 24 is a tapered cylinder. The inner peripheral edge of the annular plate part 24 is connected to the axially outer end of the mass support part 20 while being connected to the large-diameter side end of the shaped part 18. As a result, in the tubular leaf spring 14 according to the present embodiment, the mass support portion 20 has a smaller diameter than the large-diameter side end of the tapered tubular portion 18 via the annular plate portion 24, and is a tapered tube. The end portion 18 extends in the axial direction on the opposite side of the end portion on the large diameter side from the end portion on the large diameter side.

  The tapered cylindrical portion 18, the mass support portion 20, the shaft fixing portion 22, and the annular plate portion 24 can be integrally formed by, for example, subjecting a straight cylindrical fitting to diameter expansion processing or diameter reduction processing.

  Further, the shape, size, thickness, structure, etc. of the tapered cylindrical portion 18, the mass support portion 20, the shaft fixing portion 22, and the annular plate portion 24 are appropriately determined according to required spring characteristics, manufacturability, etc. The design can be changed. Further, the outer diameter dimension of the mass support portion 20 is made smaller than the inner diameter dimension of the cylindrical mass fitting 12, and the inner diameter dimension: d2 of the mass support portion 20 is equal to the inner diameter dimension of the shaft fixing portion 22: d3. It is larger than Furthermore, the outer diameter dimension of the end portion on the large diameter side of the tapered cylindrical portion 18 is made larger than the outer diameter dimension of the cylindrical mass fitting 12.

  Further, each cylindrical leaf spring 14 is formed with a plurality of slits 26. The slit 26 passes through the inner and outer surfaces of the tubular leaf spring 14, extends in the axial direction from the opening-side end edge of the shaft fixing portion 22 to the tapered tubular portion 18, and the tapered tubular portion. A portion extending from the small-diameter side end edge connected to the 18 shaft fixing portions 22 to the vicinity of the large-diameter side end edge extends in the generatrix direction of the tapered tubular portion 18 and has a notch shape as a whole. The rear end portion of the slit 24 positioned near the large-diameter side end portion of the tapered tubular portion 18, that is, near the mass support portion 20 of the tubular leaf spring 14 is gradually narrowed to have a shape that suppresses stress concentration. Has been. The slit 26 extending from the shaft fixing portion 22 to the tapered cylindrical portion 18 has a linear shape extending in the axial direction in a plan view by extending with a substantially constant width dimension over the whole. The width dimension may vary, or may be inclined or curved with respect to the axial direction of the tubular leaf spring 14 in plan view.

  By forming such a slit 26 in the cylindrical leaf spring 14, the tubular leaf spring 14 also adjusts its spring characteristics by adjusting the shape, size, number, arrangement, etc. of the slit 26. It is possible. Needless to say, the spring characteristics of the cylindrical leaf spring 14 can be adjusted by changing the taper angle in addition to the material and the member thickness.

  In particular, in the present embodiment, as shown in FIG. 2, four slits 26 as described above are formed in each cylindrical leaf spring 14, and two slits 26 a and 26 b are formed in the cylindrical leaf spring 14. Are opposed to each other in the XX direction which is a uniaxial perpendicular direction. In addition, in the YY direction as another uniaxial perpendicular direction orthogonal to the XX direction of the tubular leaf spring 14, one slit 26c is positioned on one side across the central axis of the tubular leaf spring 14. In addition, one slit 26d is positioned so as to be biased toward the slit 26a from the other side across the central axis of the cylindrical leaf spring 14. Thereby, the separation distance between the circumferential direction of the slit 26c and the slit 26a: L1, the separation distance between the circumferential direction of the slit 26a and the slit 26d: L2, and the separation distance between the circumferential direction of the slit 26d and the slit 26b: L3. Are different from each other, and the separation distance L4 between the slits 26b and 26c in the circumferential direction and the separation distance L1 between the slits 26c and 26a in the circumferential direction are the same.

  That is, in the tubular leaf spring 14 according to the present embodiment, the slits 26 are formed unevenly on the circumference of the tubular leaf spring 14, and on the basis thereof, different spring characteristics are obtained in mutually different directions perpendicular to the axis. Has been granted.

  A damping rubber 28 as a damping member is disposed on the tapered cylindrical portion 18 of the cylindrical leaf spring 14. The damping rubber 28 is fixed so as to cover the surface of the tapered cylindrical portion 18, thereby exhibiting a coating film shape as a whole. As the damping rubber 28, in addition to a known rubber material, a styrenic thermoplastic elastomer that exhibits a damping force when deformed like a rubber, or a gel-like resin material such as a polymer gel such as a hydrogel or an organogel can be used. . Specifically, as the rubber material, high-damping butyl rubber or the like is suitable, and high-damping material compositions described in Japanese Patent No. 3675216 and Japanese Patent No. 3468073 are also suitable.

  Further, a film-like covering rubber layer 30 is formed on the inner and outer peripheral surfaces of the shaft fixing portion 22 of the tubular leaf spring 14. Further, the covering rubber layer 30 is also formed on the axial end surface of the annular leaf portion 24 of the annular leaf spring 14 on the side where the mass support portion 20 protrudes.

  The damping rubber 28 and the covering rubber layer 30 are also provided in a filled state in each slit 26 of the cylindrical leaf spring 14, and the slit 26 is used when the damping rubber 28 and the covering rubber layer 30 are vulcanized. Thus, the rubber 28, 30 fixed to the inner peripheral surface side of the cylindrical leaf spring 14 and the rubber 28, 30 fixed to the outer peripheral surface side are integrally formed. As a result, the entire slit 26 is covered with the damping rubber 28 and the covering rubber layer 30 and is hidden from the outside. Here, for example, on the outer peripheral surface of the mass support portion 20 located on the slit 26 or on the axial extension line of the slit 26, the surface of the damping rubber 28, etc., a marking process is performed to attach protrusions, markings, painting, etc. Also good. Thereby, it is also possible to recognize the formation position of each slit 26 covered with the damping rubber 28 and the covering rubber layer 30 in the tubular leaf spring 14.

Further, a contact rubber layer 32 as a contact rubber elastic body is adhered and formed on the outer peripheral surface of the mass support portion 20. The contact rubber layer 32 according to the present embodiment has a mountain-shaped or semicircular cross section that swells outward from the outer peripheral surface of the mass support portion 20 in the direction perpendicular to the axis (radial direction). A plurality of rubber annular bodies extending in the direction are arranged in the axial direction. In such a contact rubber layer 32, the Shore D hardness of ASTM standard D2240 is preferably 80 or less, more preferably 20 in order to reduce contact sound with respect to the mass support portion 20 of the cylindrical mass metal fitting 12 described later. The compression elastic modulus is preferably set to 1 to 10 ⁴ MPa, more preferably 1 to 10 ³ MPa, and the loss tangent (tan δ) is preferably 1 × 10 ^{−. It is 3} or more, more preferably 0.01-10.

  Furthermore, a stopper rubber 34 projects from the large diameter side end of the tapered cylindrical portion 18 or the outer peripheral edge of the annular plate portion 24. The stopper rubber 34 protrudes in the axial direction on the side where the mass support portion 20 is formed. In particular, in the present embodiment, the stopper rubber 34 is tapered so that the diameter dimension decreases toward the protruding tip side, and the stopper rubber 34 extends in the circumferential direction. It has a ring shape that is continuous over the entire circumference. The stopper rubber 34 is opposed to the contact rubber layer 32 formed on the outer peripheral surface of the mass support portion 20 with a predetermined distance in the radial direction.

  In the present embodiment, the damping rubber 28, the covering rubber layer 30, the abutting rubber layer 32, and the stopper rubber 34 are integrally vulcanized and molded together with the cylindrical leaf spring 14, but for example, separately formed rubbers are used. It is also possible to adhere to the cylindrical leaf spring 14 using an adhesive or the like.

  The integrally vulcanized molded product of the cylindrical leaf spring 14 provided with the damping rubber 28, the contact rubber layer 32, and the like is positioned on both sides in the axial direction of the cylindrical mass fitting 12, and each contact rubber layer 32 is provided. The mass support portion 20 having the above is inserted in the cylindrical mass metal fitting 12 and each stopper rubber 34 is externally inserted in the cylindrical mass metal fitting 12. Thereby, each cylindrical leaf | plate spring 14 is arrange | positioned in the state which the taper cylindrical part 18 becomes small diameter gradually toward an axial direction outward from the axial direction both ends of the cylindrical mass metal fitting 12. As shown in FIG. In addition, the cylindrical mass metal fitting 12 has a diameter through an abutting rubber layer 32 with respect to the outer peripheral surface of the mass support portion 20 formed at the large diameter side end portion of the tapered cylindrical portion 18 on the inner peripheral surface thereof. It is superimposed in the direction.

  As a result, the cylindrical mass fitting 12 is elastically relative to the shaft fixing portion 22 and thus to the drive shaft 16 to which the shaft fixing portion 22 is fixed, based on the elastic deformation of the cylindrical leaf spring 14. Displaceable.

  Further, when large vibration is exerted in the direction perpendicular to the axis, the cylindrical mass fitting 12 is relatively displaced in the direction perpendicular to the axis with respect to the mass support portion 20 due to elastic deformation of the contact rubber layer 32. When the input vibration is further increased, the amount of elastic deformation of the contact rubber layer 32 is increased, and the amount of relative displacement of the cylindrical mass bracket 12 in the direction perpendicular to the axis with respect to the mass support portion 20 is increased, the cylindrical mass bracket. On one side in the direction perpendicular to the axis, which is the displacement direction of 12, the abutting rubber layer 32 is greatly crushed and elastically deformed by the cylindrical mass fitting 12, and at the same time, on the other side in the direction perpendicular to the axis, the cylindrical mass fitting. The inner peripheral surface of 12 is separated from the contact rubber layer 32 and floats up. By repeating this by vibration, the cylindrical mass metal fitting 12 repeatedly jumps in the direction perpendicular to the axis with respect to the mass support portion 20, and repeatedly strikes through the contact rubber layer 32.

  In the state before the cylindrical mass fitting 12 and the cylindrical leaf spring 14 are assembled, the inner diameter dimension of the protruding tip of the stopper rubber 34 may be larger than the outer diameter dimension of the cylindrical mass fitting 12 so that there is a gap. However, the inner diameter dimension of the protruding tip end portion of the stopper rubber 34 may be the same as or smaller than the outer diameter dimension of the cylindrical mass metal fitting 12 and may be in contact with each other in the assembled state.

  Further, the cylindrical mass fitting 12 and the cylindrical leaf springs 14 and 14 are opposed in the axial direction between the annular plate portion 24 of one cylindrical leaf spring 14 and the annular plate portion 24 of the other cylindrical leaf spring 14. The inter-surface distance is assembled so as to be larger than the axial dimension of the cylindrical mass fitting 12 by a predetermined amount. Accordingly, the cylindrical mass fitting 12 is prevented from being sandwiched in the axial direction by the pair of cylindrical leaf springs 14, 14, and the relative displacement in the radial direction between the cylindrical mass fitting 12 and the tubular leaf spring 14 is not hindered. It is easy to accept. In addition, when excessive vibration is input in the axial direction of the dynamic damper 10, any one axial end of the cylindrical mass fitting 12 comes into contact with the annular plate portion 24, so that the cylindrical mass is A large relative displacement in the axial direction between the metal fitting 12 and the cylindrical leaf spring 14 can be suppressed.

  In the present embodiment, the four slits 26a, 26b, 26c, and 26d formed in one cylindrical leaf spring 14 and the four slits 26a, 26b, 26c, and 26d formed in the other tubular leaf spring 14 are provided. However, the pair of cylindrical leaf springs 14 and 14 are assembled to the cylindrical mass metal fitting 12 so as to be superimposed on the positions projected in the axial direction. That is, the XX direction and the YY direction of the pair of cylindrical leaf springs 14 and 14 are positioned so as to project each other in the axial direction.

  The automotive dynamic damper 10 having the above-described structure is mounted on a drive shaft 16 as shown in FIG. 3, for example.

  The drive shaft 16 is made of a long rod-shaped rigid member having a hollow or solid circular cross section, and splined connection portions 36 and 36 are formed at both axial end portions. A universal joint (not shown) is assembled to the pair of connecting portions 36, 36, and one connecting portion 36 is connected to the output shaft of the final reduction gear device through the universal joint, and the other connecting portion 36 is connected. Are connected to the drive wheels.

  Further, between the central portion of the drive shaft 16 in the axial direction and each connecting portion 36, large-diameter ring-shaped locking portions 38, 38 project from the connecting portion 36 with a predetermined distance in the axial direction. A locking groove 40 is formed between the 38 axial directions. The locking groove 40 is for supporting the end portion of the protective cover when the protective cover is externally attached to the drive shaft 16 so as to cover each connecting portion with a protective cover (not shown).

  The drive shaft 16 according to the present embodiment extends in the axial direction with a substantially constant circular cross section except for the coupling portion 36 and the locking portion 38, and the outer diameter of the drive shaft 16 is a cylindrical mass of the automotive dynamic damper 10. Inner diameter dimension of metal fitting 12: d1 and inner diameter dimension of mass support portion 20 of cylindrical leaf spring 14: smaller than d2, and inner diameter dimension of shaft fixing portion 22 provided with covering rubber layer 30 of cylindrical leaf spring 14: It is the same as or slightly larger than d3. Further, the maximum outer diameter dimension of the drive shaft 16 is the outer diameter dimension d4 of the locking portion 38, which is smaller than the inner diameter dimension d1 of the cylindrical mass fitting 12 and the inner diameter dimension d2 of the mass support portion 20. On the other hand, the inner diameter dimension of the shaft fixing portion 22 provided with the covering rubber layer 30 is larger than d3. The outer diameter dimension d4 of the locking portion 38 is substantially the same as the outer diameter dimension of the connecting portion 36.

  In order to mount the automobile dynamic damper 10 on the drive shaft 16 as described above, the dynamic damper 10 is extrapolated from any one of the connecting portions 36 on both sides in the axial direction of the drive shaft 16, and the one connecting portion 36 and the pair of The locking portions 38, 38 are crossed in the axial direction and are positioned at a target mounting position of the drive shaft 16 (in the present embodiment, a substantially axial center portion of the drive shaft 16). Here, since the inner diameter dimension d3 of the shaft fixing portion 22 provided with the covering rubber layer 30 is smaller than the outer diameter dimension d4 of the connecting portion 36 and the locking portion 38, the dynamic damper 10 is connected to the connecting portion 36 or The damper 10 can be assembled in the axial direction by expanding the diameter of the shaft fixing portion 22 when the locking portion 38 is exceeded. Thus, with the dynamic damper 10 positioned at the target mounting position of the drive shaft 16, based on the elasticity of the cylindrical leaf spring 14 and the elasticity of the covering rubber layer 30 attached to the shaft fixing portion 22, The inner peripheral surface of the covering rubber layer 30 is closely adhered to the outer peripheral surface of the drive shaft 16, and the pair of shaft fixing portions 22, 22 of the dynamic damper 10 are externally fixed to the drive shaft 16. . In particular, the inner diameter dimension d3 of the shaft fixing portion 22 provided with the covering rubber layer 30 of the dynamic damper 10 before being attached to the drive shaft 16 is d3 in relation to the inner diameter dimension d3 ′ of the shaft fixing portion 22 after being attached. Considering that ≦ d3 ′, the inner diameter dimension d3 of the shaft fixing portion 22 is set to be smaller than the outer diameter dimension of the drive shaft 16. By adjusting the size of d3'-d3, the fitting and fixing force of the dynamic damper 10 to the drive shaft 16 can be adjusted.

  When the automobile dynamic damper 10 is mounted on the drive shaft 16 in this manner, the damper 10 and the drive shaft 16 are positioned substantially concentrically, and the tapered tubular portion 18 of the tubular leaf spring 14 is the small diameter side end portion. From the drive shaft 16 toward the large-diameter side end portion so as to gradually widen outward in the radial direction of the drive shaft 16. Further, the annular plate part 24 formed on the large diameter side of the tapered cylindrical part 18, the mass support part 20, and the cylindrical mass metal fitting 12 elastically supported by the mass support part 20 are arranged around the drive shaft 16 at a predetermined distance. Extrapolated with a gap.

  Thereby, the cylindrical mass metal fitting 12 is elastically supported with respect to the drive shaft 16 to which the shaft fixing portions 22 and 22 are fixed via the pair of tapered cylindrical portions 18 to which the damping rubber 28 is attached. ing. Based on the elastic deformation of the damping rubber 28 and the tapered cylindrical portion 18, the cylindrical mass fitting 12 is allowed to be displaced relative to the drive shaft 16.

  That is, the tapered cylindrical portion 18 that elastically supports the cylindrical mass fitting 12 has an axial cross-section inclined with respect to the axial direction of the dynamic damper 10 and the drive shaft 16, and a slit 26 is formed. Therefore, when the cylindrical mass fitting 12 is displaced in the direction perpendicular to the axis with respect to the drive shaft 16, the tapered cylindrical portion 18 can exhibit spring characteristics due to elastic deformation. In addition, along with the elastic deformation of the tapered cylindrical portion 18, the damping rubber 28 is subjected to shear deformation.

  In particular, the separation distance between the circumferential directions of the slits 26 in the four slits 26 a, 26 b, 26 c, and 26 d formed in the cylindrical leaf spring 14 is appropriately changed, so that the slit 26 is arranged around the cylindrical leaf spring 14. Due to the uneven formation above, when the cylindrical mass fitting 12 is displaced in the direction perpendicular to the axis with respect to the drive shaft 16 during vibration such as bending resonance of the drive shaft 16, the directions perpendicular to each other are different from each other. The spring characteristics different from each other can be exhibited.

  When the bending vibration of the drive shaft 16 to be damped is exerted in a direction perpendicular to the dynamic damper 10 with the dynamic damper 10 mounted as described above, the displacement of the cylindrical mass fitting 12 with respect to the drive shaft 16 is The spring characteristics of the leaf spring 14 and the damping effect of the damping rubber 28 are allowed. In other words, the cylindrical mass fitting 12 is displaced by vibration in response to the input of vibration to be damped. The vibration displacement of the cylindrical mass fitting 12 is caused by the tapered tubular portion 18 of the tubular leaf spring portion 14. This is realized by a vibration system composed of one mass-spring system in which the elasticity of the main body is the main spring and the mass of the cylindrical mass fitting 12 is the mass. In short, this one vibration system functions as a sub-vibration system with respect to the drive shaft 16 as the rotation shaft, which is the main vibration system, and thereby exhibits a vibration reduction effect that is a dynamic damper effect.

  Then, when the radial vibration to be damped is input to the dynamic damper 10 and the cylindrical mass metal fitting 12 is in a resonance state, the vibration amplitude becomes very large. As a result, the cylindrical mass metal fitting 12 is in the radial direction. The spring jumps from the contact rubber layer 32 and repeatedly strikes the mass support portion 20 of the tubular leaf spring 14 via the contact rubber layer 32. That is, a vibration reduction effect can be obtained based on energy absorption or cancellation due to friction at the time of hitting or a hitting action.

  Moreover, in the sub-vibration system of the present embodiment, when the tapered cylindrical portion 18 is deformed, the main deformation mode of the damping rubber 28 is shear deformation, and a large damping force is exhibited while suppressing a large spring rigidity due to the compressive deformation. The Rukoto. Therefore, in addition to the spring characteristic of the tapered cylindrical portion 18 which is a metal spring, a large damping force by the damping rubber 28 is also exerted, and as a result, the vibration peak of the dynamic damper effect by such a secondary vibration system is reduced. The reduction effect is exhibited.

  In short, according to the automotive dynamic damper 10 of the present embodiment, the damping effect based on the striking of the tubular mass fitting 12 against the tubular leaf spring 14 and the damping force is further improved by the damping rubber 28. The dynamic damper effect by the vibration system functions in a complex manner. Therefore, not only the peak vibration due to the resonance of the vibration member, which has been a problem before the dynamic damper 10 is mounted, but also both the upper and lower sides of the low frequency side and the high frequency side of the initial peak vibration frequency range caused by the dynamic damper effect. The new peak vibration that occurs in the frequency range is also effectively reduced, and as a result, an effective vibration reduction effect is achieved in a wide frequency range as a whole.

  In addition, since the cylindrical leaf spring 14 that constitutes the sub-vibration system spring is constituted by a metal spring, the amplitude of the tuning frequency is larger than that of a dynamic damper in which a conventional spring is constituted by a rubber elastic body. The dependence and temperature dependence are greatly suppressed. As a result, a large amplitude change appears in the vibration to be damped by being exposed to a temperature change of 50 ° C. or higher, for example, in an automobile, or by changing the magnitude of the input vibration to several tens of times depending on the driving conditions. Even in such an environment, the change in the tuning frequency of the dynamic damper 10 is suppressed, and the intended damping effect can be stably obtained.

  Moreover, in this embodiment, the contact | abutting rubber layer 32 consists of several strips of a tapered annular body, and the area overlapped with the cylindrical mass metal fitting 12 by radial direction is made small. Thereby, in addition to reducing the hitting sound associated with the contact of the cylindrical mass fitting 12 with the contact rubber layer 32, the cylindrical mass fitting 12 is utilized by utilizing the soft spring characteristic of the contact rubber layer 32. It is also possible to increase the jumping displacement from the cylindrical leaf spring 14 in the above, and to obtain a greater damping effect by the striking of the cylindrical mass fitting 12 against the tubular leaf spring 14.

  In the present embodiment, the axial end of the dynamic damper 10 is securely fitted and fixed to the drive shaft 16 by utilizing the elastic deformation action of the shaft fixing portion 22 made of a metal material such as spring steel. As a result, for example, a cylindrical dynamic damper having a conventional structure shown in Patent Document 1 (Japanese Patent Publication No. 07-47979) and Patent Document 2 (Japanese Patent Application Laid-Open No. 2000-199542) has a damper mounted on the drive shaft. There is no need to fix and fix the fixing band from the outer peripheral side of the fitting fixing portion. In addition, in this embodiment, the shaft fixing portion 22 is integrally formed with the tapered cylindrical portion 18 and the mass support portion 20. Therefore, the number of parts can be reduced and the mounting work on the drive shaft 16 can be simplified.

  Further, a plurality of slits 26 extending from the opening edge of the shaft fixing portion 22 to the vicinity of the large-diameter side end of the tapered tubular portion 18 in the tubular leaf spring 14 are spaced apart in the circumferential direction of the tubular leaf spring 14. By being formed, a large amount of diameter expansion deformation of the cylindrical leaf spring 14 is ensured. Thereby, also in the dynamic damper 10 provided with the metal cylindrical leaf | plate spring 14, extrapolation mounting | wearing from the axial direction edge part of the drive shaft 16 like illustration using the diameter expansion deformation of the cylindrical leaf | plate spring 14 is carried out. Therefore, simplification of the mounting operation can be achieved more advantageously.

  Further, the tuning frequency setting can be changed with a simple structure based on the design change such as the size, shape, number, and arrangement of the slits 26 formed in the cylindrical leaf spring 14.

  In particular, in the present embodiment, since the plurality of slits 26 are formed unevenly on the circumference of the tubular leaf spring 14, different spring characteristics can be imparted to the tubular leaf spring 14 in different bending directions. Therefore, a plurality of natural tuning frequencies in the bending direction of the automotive dynamic damper 10 can be set in different bending directions. In the present embodiment, since the dynamic damper 10 rotates together with the drive shaft 16, the vibration damping effect can be effectively exhibited in a wide frequency range that is broadened by connecting a plurality of tuning frequency ranges as a whole.

  Further, in the present embodiment, the damping rubber 28 is vulcanized and bonded so as to cover the surface of the cylindrical leaf spring 14, whereby the tubular leaf spring 14 is formed as an integrally vulcanized molded product including the damping rubber 28. As a result, the number of parts is reduced, and the assembly work of the cylindrical leaf spring 14 and the damping rubber 28 is simplified.

  Further, a coating rubber layer 30 formed integrally with the damping rubber 28 is formed on the surface of the shaft fixing portion 22 of the cylindrical leaf spring 14, and the shaft fixing portion 22 and the drive are attached to the drive shaft 16. The sandwiched rubber layer 30 functions as a seal member by being sandwiched between the shafts 16. Therefore, the sealing performance between the mounting surface of the dynamic damper 10 and the drive shaft 16 can be improved with a simple structure.

  Here, in the dynamic damper 10 having the structure according to the present embodiment, a test was performed in order to confirm that the damping effect is exhibited in a wide frequency range. The result is shown in FIG. In the example shown by a solid line in FIG. 4, the vibration level when the dynamic damper 10 for an automobile of the present embodiment is assembled to a test member equivalent to the drive shaft 16 and the test member is subjected to vibration displacement with a predetermined amplitude is shown. It is the result of measurement. However, in this experiment, in each of the pair of cylindrical leaf springs 14, 14, the slits 26 extending in the axial direction were formed at equal intervals in the circumferential direction as an example.

  Moreover, the comparative example 1 shown with a broken line in FIG. 4 is the result of having measured the vibration level of the test member on the same conditions as an Example, without attaching a dynamic damper to the said test member. Further, in Comparative Example 2 shown by the one-dot chain line in FIG. 4, the automobile dynamic damper 10 of the above-described embodiment employs the cylindrical mass metal fitting 12 fixed to the cylindrical leaf spring 14 so as not to jump. In addition, the vibration level of the test member was measured under the same conditions as in the example.

  According to the result shown in FIG. 4, it is recognized that the bending vibration generated in the drive shaft can be effectively reduced over a wide frequency range in the embodiment having the structure according to the present invention.

  In addition, a combination structure of dynamic damper constituent members composed of a plurality of sets each including a plurality of types of cylindrical mass fittings 12 having different masses and a plurality of types of cylindrical leaf springs 14 and 14 having different spring characteristics. In the body, the dynamic damper 10 according to the present embodiment can be employed for at least one dynamic damper.

  That is, the cylindrical mass fitting 12 having a predetermined mass is selected and adopted from a plurality of types of mass fittings, and the cylindrical leaf spring 14 having a predetermined spring characteristic is selected from the plurality of types of cylindrical leaf springs having a spring characteristic. And adopt. Then, by combining each of the selected cylindrical mass fittings 12 and the cylindrical leaf spring 14, a secondary vibration system having a target tuning frequency can be realized. According to this, it is possible to quickly and efficiently provide a plurality of types of dynamic dampers 10 having different tuning frequencies upon request.

  Specifically, as one method of changing the design of the tuning frequency of the dynamic damper 10 for an automobile with the combined structure of the dynamic damper components as described above, for example, the second of the present invention as shown in FIG. It is also possible to adopt the dynamic damper 42 as an embodiment. In addition, in the following description, about the member and site | part made into the structure substantially the same as the said embodiment, those detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol as the said embodiment.

  That is, in the tubular leaf spring 44 as a tubular metal spring having the tapered tubular portion 18 at the axially intermediate portion, the shaft fixing portion 22 is integrally formed at the small diameter side end portion of the tapered tubular portion 18. On the other hand, a straight cylindrical mass support portion 46 is integrally formed at the large-diameter side end portion of the tapered cylindrical portion 18.

  A damping rubber 48 is fixed to the tapered tubular portion 18 in a substantially embedded state. The damping rubber 48 spreads in a film shape over substantially the entire outer peripheral surface of the tapered cylindrical portion 18, while the cross section protrudes inward from the inner peripheral surface of the tapered cylindrical portion 18 in a direction substantially perpendicular to the axis. It extends in the circumferential direction. Further, a buffer rubber 50 extending in the circumferential direction with a substantially constant rectangular cross section is attached to the inner peripheral surface of the mass support portion 46, and the contact rubber layer 32 is integrated with the inner peripheral surface of the buffer rubber 50. Is formed.

  Furthermore, a seal lip 52 as an annular seal is provided at the opening edge of the shaft fixing portion 22 so as to protrude radially inward from the inner peripheral surface of the shaft fixing portion 22. The seal lip 52, the damping rubber 48, the buffer rubber 50, and the contact rubber layer 32 are integrally formed. Further, the seal lip 52, the damping rubber 48, the shock absorbing rubber 50, and the contact rubber layer 32 may extend continuously over the entire circumference in the circumferential direction, or may extend at a distance less than one circumference in the circumferential direction. It is also possible to form a plurality of them separated in the circumferential direction.

  The mass support portions 46 of the respective cylindrical leaf springs 44 are arranged to be extrapolated at the respective axial ends of the cylindrical mass metal fitting 12, and both axial sides of the cylindrical mass metal fitting 12 are connected to the respective contact rubber layers 32 and It is elastically supported by the mass support part 46 via the buffer rubber 50. Further, the axial end surface of the cylindrical mass fitting 12 is separated from the axial end surface of the damping rubber 48 fixed to the inner peripheral surface of the tapered cylindrical portion 18 by a predetermined distance in the axial direction.

  Further, when the dynamic damper 42 is mounted on the drive shaft 16, the shaft fixing portion 22 of the cylindrical leaf spring 14, the damping rubber 48, etc. are expanded and deformed while being extrapolated to the drive shaft 16, By releasing, the shaft fixing portion 22 is superimposed on the drive shaft 16 in close contact. There, the seal lip 52 formed integrally with the damping rubber 48 is compressed and deformed, and is superimposed on the outer peripheral surface of the drive shaft 16 in close contact with each other, whereby the shaft fixing portion 22 and the drive shaft 16 are connected. The sealing performance between the mounting surfaces can be improved with a simple structure.

  By adopting the cylindrical leaf spring 44 including the mass support portion 46 having a diameter larger than that of the cylindrical mass fitting 12, a large degree of design freedom of the contact rubber layer 32 is ensured. The cushioning rubber 50 as illustrated may be provided, and as a result, the degree of freedom in tuning the damping effect based on the hitting action can be improved.

  Further, as in the third embodiment of the present invention shown in FIG. 6, the contact rubber layer 54 may be provided not on the cylindrical leaf spring 44 side but on the cylindrical mass fitting 12 side. The abutting rubber layer 54 according to the present embodiment is a thin rubber layer that is vulcanized and bonded over the entire surface of the cylindrical mass fitting 12 and is opposed to the mass support portion 46 of the cylindrical leaf spring 44 in the radial direction. Consists of parts that can be positioned.

  Furthermore, the taper tubular portion 18 of the tubular leaf spring 44 according to the third embodiment is formed with a radial plate portion 56 that spreads in a thin plate shape in the radial direction, and the axial end of the tubular mass metal fitting 12. It is made to oppose the part at a predetermined distance in the axial direction. One or more radial plate portions 56 may be provided on the tapered cylindrical portion 18 or spaced apart from each other by a predetermined distance in the circumferential direction. As a result, the spring characteristics of the tubular leaf spring 14 are tuned and changed based on the form of the radial plate portion 56, and in addition to the annular plate portion 24 of the first embodiment, the tubular mass bracket. The 12 axial end portions abut against the radial plate portion 56, so that a large relative displacement in the axial direction between the cylindrical mass fitting 12 and the cylindrical leaf spring 14 can be limited.

  Further, in the first embodiment and the second embodiment, the cylindrical mass metal fitting 12 is abutted in a state where the cylindrical mass metal fitting 12 and the cylindrical leaf springs 14 and 44 are positioned concentrically with each other. Although it overlapped with the mass support parts 20 and 46 via the rubber contact layer 32 in the radial direction, it is not always necessary to overlap, and the cylindrical mass metal fitting 12 and the mass support part 46 are not necessarily overlapped as in the third embodiment. They may be separated in the radial direction. When the radial mass vibration is input, the cylindrical mass metal fitting 12 is brought into contact with the mass support portion 46 via the contact rubber layer 54 and is elastically supported by the mass support portion 46 until it is separated again. You may make it exhibit the vibration reduction effect which is a dynamic damper effect.

  Further, in the first embodiment, the second embodiment, and the third embodiment, the pair of cylindrical leaf springs 14 and 14 (44, 44) are spaced apart from each other in the axial direction with the cylindrical mass fitting 12 interposed therebetween. However, as in the fourth embodiment of the present invention shown in FIG. 7, the axial end of the mass support portion 46 of one cylindrical leaf spring 44 is larger in diameter than the mass support portion 46. The cylindrical large-diameter cylindrical portion 58 is integrally formed, and the axial end of the mass support portion 46 of the other cylindrical leaf spring 44 is extended outward in the axial direction, and is press-fitted and fixed to the large-diameter cylindrical portion 58. Accordingly, the pair of cylindrical leaf springs 44 and 44 may be fixed to each other, and the cylindrical mass metal fitting 12 may be covered with the cylindrical leaf springs 44 and 44 over the entire surface. That is, in the fourth embodiment, a cover sleeve that extends in the axial direction across the tapered tubular portions 18 and 18 of the pair of tubular leaf springs 44 and 44 and covers the outer peripheral side of the tubular mass fitting 12 is provided. The mass support portions 46 and 46 and the large diameter cylindrical portion 58 are included.

  Alternatively, as in the fifth embodiment of the present invention shown in FIG. 8, the cover sleeve 60 has a cylindrical shape with a larger diameter than the end on the large diameter side of the tapered tubular portion 18 of the tubular leaf spring 14. On the other hand, the large-diameter side end of each tapered tubular portion 18 is press-fitted and fixed, or the cover sleeve 60 is extrapolated to the large-diameter side end of each tapered tubular portion 18 and the cover sleeve 60 is squeezed in eight directions. It is also possible to fit and fix the cover sleeve 60 to the pair of cylindrical leaf springs 14 and 14 by performing the diameter reduction process.

  In addition, as in the sixth embodiment of the present invention shown in FIG. 9, the cylindrical plate spring 44 has a cylindrical shape having a smaller diameter than the mass support portion 46 at the axial end of the mass support portion 46. The small-diameter cylindrical portion 62 is integrally formed, and the axial end of the mass support portion 46 of the other cylindrical leaf spring 44 is extended outward in the axial direction so that the small-diameter cylindrical portion 62 and the other mass support portion 46 are connected. A pair of cylindrical leaf springs 44 and 44 are fixed to each other and inserted into the cylindrical mass bracket 12 and the small-diameter cylindrical portion 62 is press-fitted and fixed to the other mass support portion 46. The pair of mass support portions 46, 46 may be opposed to each other with a predetermined distance therebetween. Thereby, the striking part with respect to the cylindrical leaf | plate springs 44 and 44 of the cylindrical mass metal fitting 12 is ensured largely in the axial direction.

  Further, a notch-like hole 64 is provided in the vicinity of the tapered cylindrical portion 18 of the mass support portion 46 according to the sixth embodiment, and the inside of the hole 64 is raised radially outward, thereby causing the radial direction. A plate portion 66 may be provided so that the cylindrical mass metal fitting 12 is disposed with a predetermined gap between the axially opposed surfaces of the pair of radial plate portions 66 and 66. One radial plate portion 66 may be formed on each cylindrical plate spring 44, or a plurality of radial plate portions 66 may be provided at a predetermined distance in the circumferential direction. Thereby, the axial direction edge part of the cylindrical mass metal fitting 12 contact | abuts to the radial direction plate part 66 similarly to the annular plate part 24 of 1st embodiment, and the radial direction plate part 56 of 3rd embodiment. Thus, a large relative displacement in the axial direction between the cylindrical mass fitting 12 and the cylindrical leaf spring 14 can be limited.

  In addition, as in the seventh embodiment of the present invention shown in FIG. 10, the cylindrical mass fitting 12 is provided at the radial intermediate portion of the covering rubber layer 30 formed on the axial end surface of the annular plate portion 24. The axial projection 68 extending in a tapered manner toward the axial end face is integrally formed with the covering rubber layer 30, and the cylindrical mass fitting 12 is extrapolated on the mass support portion 20. 68 may be brought into contact with the axial end surface of the mass fitting 12. The axial projections 68 may extend continuously in the circumferential direction, or a plurality of axial projections 68 may be formed apart in the circumferential direction. Further, a plurality of strips may be provided apart from each other in the radial direction of the covering rubber layer 30. The both ends in the axial direction of the cylindrical mass metal fitting 12 are elastically supported by the annular plate portions 24 and 24 of the cylindrical leaf springs 14 and 14 through the tapered axial protrusions 68 as described above, thereby forming a cylindrical shape. The relative displacement in the axial direction of the cylindrical mass fitting 12 and the cylindrical leaf spring 14 is further advantageously suppressed while suppressing the interference of the relative displacement in the radial direction between the mass fitting 12 and the mass support portion 20. The radial striking action of the cylindrical mass fitting 12 and the cylindrical leaf spring 14 is more stably exhibited.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the specific descriptions in these embodiments, and various changes, modifications, and improvements based on the knowledge of those skilled in the art. Needless to say, any of these embodiments can be included in the scope of the present invention without departing from the spirit of the present invention.

  For example, the shape, size, structure, number, arrangement, and the like of the tapered tubular portion 18, the mass support portion 20, the shaft fixing portion 22, etc. in the tubular leaf springs 14 and 44 can be arbitrarily set.

  In the first embodiment, the slits 26 formed in each cylindrical leaf spring 14 are all of the same standard having the same shape, size, etc., but each has a different standard. May be adopted.

  Further, the slit 26 and the damping rubber 28 are provided according to required deformation characteristics of the shaft fixing portion 22, tuning characteristics of the spring characteristics, damping performance, and the like, and are not essential constituent requirements.

  Further, a metal or resin fastening band may be fastened and fixed to the outer peripheral side of the shaft support portion 22 that is externally fitted and fixed to the drive shaft 16 as required.

  In addition, in the said embodiment, although the specific example of what applied this invention to the dynamic damper for drive shafts of a motor vehicle was demonstrated, this invention is mounted | worn with various rotating shafts other than a motor vehicle besides the propeller shaft of a motor vehicle. The present invention can also be applied to a cylindrical dynamic damper.

It is a longitudinal cross-sectional view of the dynamic damper for motor vehicles as 1st embodiment of this invention, Comprising: The figure equivalent to the II cross section of FIG. II-II sectional drawing of FIG. The longitudinal cross-sectional view which shows the state which mounted | wore the drive shaft with the dynamic damper for motor vehicles of FIG. The graph which shows the result of the test done in order to confirm about the damping effect of the cylindrical dynamic damper made into the structure according to this invention with a comparative example. The longitudinal cross-sectional view of the dynamic damper for motor vehicles as 2nd embodiment of this invention. The longitudinal cross-sectional view of the dynamic damper for motor vehicles as 3rd embodiment of this invention. The longitudinal cross-sectional view of the dynamic damper for motor vehicles as 4th embodiment of this invention. The longitudinal cross-sectional view of the dynamic damper for motor vehicles as 5th embodiment of this invention. The longitudinal cross-sectional view of the dynamic damper for motor vehicles as 6th embodiment of this invention. The longitudinal cross-sectional view which expands and shows the principal part of the dynamic damper for motor vehicles as 7th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Dynamic damper for motor vehicles, 12: Cylindrical mass metal fitting, 14: Cylindrical leaf | plate spring, 16: Drive shaft, 18: Tapered cylindrical part, 22: Shaft fixing | fixed part, 32: Contact rubber layer

Claims (8)

In the cylindrical dynamic damper that is attached to the rotating shaft in an extrapolated state and suppresses vibration to be damped of the rotating shaft,
Using a cylindrical mass member having an inner diameter larger than the outer diameter of the rotating shaft and a pair of cylindrical metal springs having a tapered cylindrical portion at an axially intermediate portion, from both axial ends of the cylindrical mass member Rotating shaft fixing portion in which each cylindrical metal spring is disposed in a state of gradually decreasing in diameter toward the outer side in the axial direction, and a small diameter side end portion of each cylindrical metal spring is fitted and fixed to the rotating shaft. On the other hand, at the large-diameter side end of each cylindrical metal spring, the cylindrical mass member is overlapped in the radial direction via a contact rubber elastic body and supported so as to be relatively displaceable, and at least radial vibration input is performed. Under the resonance state of the cylindrical mass member elastically supported by the cylindrical metal spring, the cylindrical mass member jumps from the cylindrical metal spring and is relatively displaced in the radial direction via the corresponding rubber elastic body. Cylindrical dynamic damper characterized by repeated striking   2. The cylindrical dynamic damper according to claim 1, wherein in each of the pair of cylindrical metal springs, at least one slit extending from the rotating shaft fixing portion to the tapered cylindrical portion is formed on the circumference.   The cylindrical dynamic damper according to claim 2, wherein the slits are formed unevenly on the circumference of the cylindrical metal spring.   The cylindrical dynamic damper according to any one of claims 1 to 3, further comprising a damping member that is shear-deformed in accordance with elastic deformation of the pair of cylindrical metal springs when vibration is input in a direction perpendicular to the axis.   The cylindrical dynamic damper according to claim 4, wherein the damping member is configured by fixing a damping material made of a polymer material so as to cover a surface of the cylindrical metal spring.   The pair of cylindrical metal springs are independent from each other, and both axial end portions of the cylindrical mass member are radially separated from each other by the large-diameter side ends of the pair of cylindrical metal springs. The cylindrical dynamic damper according to any one of claims 1 to 5, wherein at least a hitting portion in a radial direction of the cylindrical mass member is formed.   The cylindrical dynamic according to any one of claims 1 to 6, further comprising a cover sleeve that is spaced apart on the outer peripheral side of the cylindrical mass member and extends in the axial direction across the pair of cylindrical metal springs. damper.   The cylindrical dynamic according to any one of claims 1 to 7, wherein an annular seal protruding radially inward and extending in a circumferential direction is formed in an opening portion on a small diameter side of the pair of cylindrical metal springs. damper.

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