JP5944282B2 - Dynamic damper for hollow shaft - Google Patents

Description

  The present invention relates to a dynamic damper that is attached to an inner circumferential space of a hollow shaft, such as a propeller shaft of an automobile, and suppresses vibration and noise generated in the hollow shaft.

  Typical conventional technology of a dynamic damper that is installed in the inner space of the propeller shaft that transmits the driving force output from the engine of the automobile via the transmission to the rear wheels and suppresses vibration and noise generated in the propeller shaft Are disclosed in Patent Documents 1 to 4 below.

  Among these, the dynamic damper disclosed in Patent Document 1 is an outer press-fitted into the inner periphery of the propeller shaft 100 via an elastic layer 104 made of a rubber material or a synthetic resin material having rubber-like elasticity, as shown in FIG. An elastic body 103 made of a rubber material or a synthetic resin material having rubber-like elasticity is interposed between the ring 101 and a metal mass body 102 arranged on the inner periphery thereof, and the elastic body 103 has a circumferential direction or the like. The mass body 102 is elastically connected to the outer ring 101 by a plurality of elastic support portions 103a formed at intervals.

  Further, as shown in FIG. 8, the dynamic damper disclosed in Patent Document 2 is arranged on both sides in the axial direction of the metal mass body 202 inserted loosely on the inner periphery of the propeller shaft 200, and on the inner peripheral surface of the propeller shaft 200. The cylindrical elastic body 201 to be fitted is integrally formed, and since the elastic body 201 becomes a shear spring with respect to the input vibration in the direction perpendicular to the axis, the spring constant is lowered to reduce the low frequency region. Excellent dynamic vibration absorption characteristics can be ensured.

  Further, as shown in FIG. 9, the dynamic damper disclosed in Patent Document 3 includes a propeller shaft by press-fitting fixing metal fittings 303 on both sides in the axial direction of a metal mass body 302 that is loosely inserted into the inner periphery of the propeller shaft 300. A cylindrical elastic body 301 that is fitted to the inner peripheral surface of 300 is integrally formed. Like the dynamic damper shown in FIG. 8, the elastic body 301 becomes a shear spring against input vibration in the direction perpendicular to the axis. It is.

  Further, the dynamic damper disclosed in Patent Document 4 is the same, and as shown in FIG. 10, the propeller shaft 400 is provided on both sides in the axial direction of the metal mass body 402 that is loosely inserted into the inner periphery of the propeller shaft 400. An annular elastic body 401 fitted on the inner peripheral surface is integrally formed, and the elastic body 401 serves as a shear spring against input vibration in the direction perpendicular to the axis.

JP-A-9-53686 JP 2007-177830 A JP-A-5-149386 JP 2003-294025 A

  However, in any of the dynamic dampers shown in FIGS. 7 to 10 (Patent Documents 1 to 4), the elastic body is the inner peripheral surface of the propeller shaft in order to ensure the required fitting force and natural frequency with respect to the inner peripheral surface of the propeller shaft. For this reason, the elastic body cannot follow the change in the inner diameter of the propeller shaft, and the fitting force with respect to the inner peripheral surface of the propeller shaft greatly changes. It has been necessary to change the diameter of the elastic body according to the inner diameter of the shaft.

  The present invention has been made in view of the above points, and its technical problem is that the dynamic damper attached to the inner peripheral surface of a hollow shaft such as a propeller shaft can be used for various purposes such as changing the inner diameter of the hollow shaft. It is to provide a dynamic damper having excellent properties.

  As a means for effectively solving the technical problem described above, a hollow shaft dynamic damper according to the invention of claim 1 includes a mass body loosely inserted on an inner periphery of a hollow shaft to be reduced in vibration, An elastic body made of a rubber-like elastic material that is coupled to both axial sides and is fitted to the inner peripheral surface of the hollow shaft, and a spring that biases the elastic body in the radial direction from the inner peripheral side thereof. Is. The rubber-like elastic material here is a rubber material or a synthetic resin material having rubber-like elasticity.

  According to the hollow shaft dynamic damper having the configuration of claim 1, the elastic body is coupled to both sides in the axial direction of the mass body and fitted to the inner peripheral surface of the hollow shaft, thereby shearing in the radial direction. Since it becomes a spring, the freedom degree to a radial direction becomes high. The elastic body is biased toward the radially outer side by a spring disposed on the inner peripheral side thereof, so that a required fitting force to the inner peripheral surface of the hollow shaft is ensured, and the diameter of the inner peripheral surface of the hollow shaft is ensured. The followability of the elastic body to the change in dimension is compensated by the biasing force of the spring.

  A dynamic damper for a hollow shaft according to a second aspect of the invention is characterized in that, in the configuration described in the first aspect, the elastic body is divided into a plurality of circumferential directions.

  According to the dynamic damper for a hollow shaft having the configuration according to claim 2, since the degree of freedom in the radial direction is increased by dividing the elastic body into a plurality of circumferential directions, the radial dimension of the inner peripheral surface of the hollow shaft is increased. The followability of the elastic body to the change is further improved.

  According to the dynamic damper for a hollow shaft according to the present invention, the followability of the elastic body to a change in the diameter of the inner peripheral surface of the hollow shaft is improved by the biasing force of the spring, and the elastic body is fitted to the inner peripheral surface of the hollow shaft. Since the resultant force is compensated by the biasing force of the spring, versatility with respect to a change in the inner diameter dimension of the hollow shaft can be improved.

It is sectional drawing of the mounting state which cut | disconnects and shows preferable embodiment of the dynamic damper for hollow shafts which concerns on this invention by the plane which passes along an axial center. It is a perspective view which shows preferable embodiment of the dynamic damper for hollow shafts which concerns on this invention. 1 is a cross-sectional perspective view showing a preferred embodiment of a hollow shaft dynamic damper according to the present invention by cutting along a plane passing through an axis. It is a perspective view which shows an example of the spring used by this invention. It is a perspective view which shows the other example of the spring used by this invention. It is sectional drawing which cut | disconnects the preferable embodiment of the dynamic damper for hollow shafts which concerns on this invention to the odd-shaped propeller shaft, and cut | disconnects by the plane which passes along an axial center. It is sectional drawing which cuts and shows an example of the conventional dynamic damper for hollow shafts in the plane which passes along an axial center. It is a cross-sectional perspective view which cuts and shows the other example of the conventional dynamic damper for hollow shafts in the plane which passes along an axial center. It is sectional drawing which cuts and shows the other example of the conventional dynamic damper for hollow shafts in the plane which passes along an axial center. It is sectional drawing which cuts and shows the other example of the conventional dynamic damper for hollow shafts in the plane which passes along an axial center.

  Hereinafter, preferred embodiments of a dynamic damper for a hollow shaft according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the dynamic damper 1 in this embodiment is attached to an inner peripheral surface 2a of a propeller shaft 2 of an automobile. The propeller shaft 2 corresponds to the hollow shaft described in claim 1.

  The dynamic damper 1 includes a mass body 11 that is loosely inserted into the inner periphery of the propeller shaft 2 that is subject to vibration reduction, and a rubber-like elastic material (rubber material or rubber-like elasticity that is positioned on both sides in the axial direction of the mass body 11. And the elastic bodies 12 and 12 integrally formed with the synthetic resin material) and springs 13 and 13 for urging each elastic body 12 from the inner peripheral side thereof toward the radially outer side.

  Among these, the mass body 11 is made of a relatively thick cylindrical body made of metal, for example, and has a smaller diameter than the inner peripheral surface 2 a of the propeller shaft 2.

  As shown in FIG. 2 or FIG. 3, each of the elastic bodies 12 and 12 has a divided shape like a collet chuck. That is, the truncated cone is formed in a radial direction and an axial direction from the V-shaped recess 12a and its deepest portion. It is composed of four elastic blocks 121 having a shape divided in the circumferential direction by the extending grooves 12b, and an end surface corresponding to the bottom surface of the truncated cone (a surface perpendicular to the central axis of the cylindrical mass body 11) is axially outside. Are arranged on both sides in the axial direction of the mass body 11, and the base portion of each elastic block 121 is vulcanized and bonded to both end portions in the axial direction of the mass body 11.

  The elastic blocks 121, 121,... Constituting each elastic body 12 have their root portions continuous in the circumferential direction.

  For example, as shown in FIG. 4, the spring 13 is formed by cutting a metal tube 131 into a ring and cutting it at one place in the circumferential direction, as shown in FIG. 5, or a wire spring in which a wire 132 is formed in a C shape. Are preferably used. The inner periphery of each elastic body 12 (the inner periphery of the elastic block 121) is a circular hole 12c concentric with the inner peripheral hole 11a of the cylindrical mass body 11, and the spring 13 is in the circular hole 12c. It arrange | positions and it fits with the internal peripheral surface of each elastic block 121 in the elastic body 12. FIG.

  The spring 13 is not limited to the illustrated one, but preferably generates a biasing force in the radial direction and has a linear or approximate spring characteristic.

  The outer diameter of the elastic body 12, in other words, the outer diameter portion 121 a of each elastic block 121 is larger than the outer diameter of the mass body 11. Further, the outer diameter portion 121a of each elastic block 121 urged outward in the radial direction by the diameter expansion deformation force of the spring 13 has an appropriate tightening margin with respect to the inner peripheral surface 2a of the propeller shaft 2. In a state before being mounted on the propeller shaft 2, the diameter is appropriately larger than the inner peripheral surface 2a of the propeller shaft 2.

  The radial resonance frequency of the dynamic damper 1 is set to a frequency band in which the amplitude of radial vibration generated in the propeller shaft 2 is maximized by the mass of the mass body 11 and the radial shear spring constant of the elastic block 121.

  As shown in FIG. 1, the dynamic damper 1 configured as described above press-fits the elastic bodies 12, 12 on both sides in the axial direction of the mass body 11 to predetermined positions on the inner peripheral surface 2 a of the propeller shaft 2. It is attached by doing.

  At this time, in the elastic bodies 12, 12, each elastic block 121 is bent radially inward by press-fitting into the inner peripheral surface 2 a of the propeller shaft 2. For this reason, the elastic body 12 (elastic block 121) is propellerd by the diameter reduction deformation of the spring 13 disposed in a state of fitting with the inner peripheral surface of the elastic block 121 in the circular hole 12c on the inner periphery of each elastic body 12. An urging force that presses against the inner peripheral surface 2a of the shaft 2 is generated.

  Here, for example, when the fixing force of the dynamic damper depends only on the compression reaction force of the elastic body due to press-fitting into the propeller shaft, the compression reaction force of the rubber-like elastic material changes nonlinearly with the amount of compression. Even if the compression amount is slightly small, the fixing force on the inner peripheral surface of the propeller shaft is remarkably reduced. Conversely, even if the compression amount is slightly increased, the fixing force on the inner peripheral surface of the propeller shaft is remarkably increased. The directional resonance frequency also changes greatly.

  On the other hand, according to the illustrated embodiment, the elastic body 12 is divided into a plurality of elastic blocks 121 in the circumferential direction, thereby providing a large degree of freedom in the radial direction, and the spring 13 made of metal is Since it has a linear spring characteristic with respect to the amount of bending in the radial direction, the fitting force of the elastic body 12 (elastic block 121) to the inner peripheral surface 2a of the propeller shaft 2 can be effectively compensated. That is, the elastic body 12 (elastic block 121) can follow the change in the inner diameter dimension of the propeller shaft 1 to ensure a good fitting state, and the damper characteristic due to the change in the compression amount of the elastic body 12 itself. Since the change is also reduced, the versatility with respect to the change of the inner diameter dimension of the propeller shaft 1 is improved.

  In addition, even if the outer diameter portion 121a of the elastic block 121 is settling due to the pressure contact with the inner peripheral surface 2a of the propeller shaft 2, the decrease in the fitting force caused thereby is compensated by the spring 13, so that it is stable over a long period of time. The fitting force can be maintained.

  Further, as shown in FIG. 6, the propeller shaft 2 has an irregular shape, for example, a large diameter portion 21 and small diameter portions 22 formed on both sides in the axial direction, and the dynamic damper 1 is connected to the large diameter portion 21. When it is desired to attach to the inner peripheral surface 21a, in the case of the conventional structure, when the small diameter portion 22 is passed, the amount of compression of the elastic body becomes excessive and the press-fitting resistance increases, so that the attachment is difficult. According to the dynamic damper 1 according to the present invention, since the degree of freedom of the elastic body 12 (elastic block 121) in the radial direction is large, it can easily pass through the inner peripheral surface 22a of the small diameter portion 22 of the propeller shaft 2. After passing through the small-diameter portion 22, the elastic block 121 is expanded in diameter by the biasing force of the spring 13, and a sufficient fitting force with respect to the inner peripheral surface 21 a of the large-diameter portion 21 of the propeller shaft 2 is ensured. It can be.

1 Dynamic damper 2 Propeller shaft (hollow shaft)
11 Mass body 12 Elastic body 121 Elastic block 13 Spring

Claims (2)

  A mass body loosely inserted into the inner periphery of the hollow shaft to be reduced in vibration, and an elastic body made of a rubber-like elastic material coupled to both sides in the axial direction of the mass body and fitted to the inner peripheral surface of the hollow shaft; A hollow shaft dynamic damper comprising a spring for urging the elastic body in a radial direction from an inner peripheral side thereof.   The hollow shaft dynamic damper according to claim 1, wherein the elastic body is divided into a plurality of circumferential directions.

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