JP2012233523A - Dynamic damper for vehicle drive shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic damper for a vehicle drive shaft that suppresses internal entry of a foreign matter.SOLUTION: The dynamic damper for the vehicle drive shaft includes: a through-hole 36 provided to penetrate the damper from an inner circumference surface 30 to an outer circumference; and a valve structure 38 that closes the through-hole 36 by a centrifugal force in axial center rotation of a the driveshaft 12, and allows the through-hole 36 to be opened in non-rotation. Accordingly, in the rotation of the drive shaft 12, closing the through-hole 36 suppresses the foreign matter from being entered from outside, while in the non-rotation of the drive shaft 12, opening the through-hole 36 can eject the internal foreign matter. In other words, the dynamic damper 22 for the vehicle drive shaft for suppressing the internal entry of the foreign matter can be provided.

Description

  The present invention relates to a dynamic damper for a drive shaft of a vehicle, and more particularly, to an improvement for suppressing entry of foreign matter into the damper.

  There is known a dynamic damper for a drive shaft of a vehicle that is fixed to a part of the drive shaft of the vehicle in a state where the drive shaft penetrates and suppresses vibration of the drive shaft. Such a dynamic damper suppresses vibration of the drive shaft by resonating when vibration is generated in the attached drive shaft, and has a specific resonance frequency (natural frequency). In such a dynamic damper for a drive shaft of a vehicle, since intrusion of foreign matters such as water into the inside, that is, between the drive shaft and the dynamic damper, becomes a problem, a technique for solving such a problem has been proposed. Yes. For example, this is the dynamic damper described in Patent Document 1. According to this technology, the discharge groove for discharging the intruding material that has entered the through hole of the dynamic damper main body portion to the outer wall is formed so as to easily remove the foreign material that has entered the driving force transmission shaft. It is said that it can be eliminated.

JP 2011-12709 A

  However, in the conventional technique, foreign matters such as water entering the inside of the dynamic damper cannot be sufficiently removed. If foreign matter such as water accumulates between the drive shaft and the dynamic damper, there is a possibility that the durability may be affected due to the progress of rust inside. For this reason, development of a dynamic damper for a vehicle drive shaft that suppresses intrusion of foreign matter into the interior has been demanded.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a dynamic damper for a drive shaft of a vehicle that suppresses entry of foreign matter into the interior.

  In order to achieve such an object, the gist of the first aspect of the present invention is to provide a vehicle drive that is fixed to a part of the drive shaft of the vehicle in a state where the drive shaft penetrates and suppresses vibration of the drive shaft. A dynamic damper for the shaft, and a through hole provided to penetrate from the inner peripheral surface of the dynamic damper to the outer peripheral side, and the through hole is closed by a centrifugal force when rotating around the axis of the drive shaft; And a valve structure that allows the through-hole to conduct when not rotating.

  As described above, according to the first aspect of the present invention, the through hole provided through the inner peripheral surface of the dynamic damper from the inner peripheral surface to the outer peripheral side, and the through hole by centrifugal force when rotating around the axis of the drive shaft are formed. A valve structure that closes and allows the through-hole to conduct when not rotating, so that when the drive shaft rotates, the through-hole is closed to prevent entry of foreign matter from the outside. During non-rotation, the foreign matter inside can be discharged by conducting the through hole. That is, it is possible to provide a vehicle drive shaft dynamic damper that suppresses the intrusion of foreign matter into the interior.

  Here, the gist of the second invention subordinate to the first invention is that the through hole is provided on one end side in the axial direction of the dynamic damper, and the inner periphery of the dynamic damper is provided. A cylindrical space is formed between the surface and the outer peripheral surface of the drive shaft, the diameter of which is gradually reduced from the end on the side where the through hole is provided toward the other end. . In this way, when the through-hole is made conductive when the drive shaft is not rotating, the internal foreign matter is discharged to the outside through the inner peripheral surface of the dynamic damper by gravity, and more preferably dynamic Intrusion of foreign matter into the damper can be suppressed.

It is a figure showing roughly the composition of the undercarriage in the power transmission device of vehicles in which the dynamic damper of the present invention is applied suitably. It is sectional drawing cut | disconnected and shown in the plane containing an axis common to a drive shaft, in order to demonstrate the structure of the dynamic damper of a present Example. It is the front view which looked at FIG. 2 from the direction shown by arrow III. FIG. 3 is a partial cross-sectional view showing an enlarged portion of the dynamic damper of FIG. 2 in order to explain the configuration around the through hole, and shows a state in which the through hole is made conductive. FIG. 3 is a partial cross-sectional view showing an enlarged portion of the dynamic damper in FIG. 2 in order to explain the configuration around the through hole, and shows a state where the through hole is closed. It is sectional drawing which cut | disconnects and shows the conventional dynamic damper attached to the drive shaft by the plane containing a common shaft center with the drive shaft for the comparison with the dynamic damper of a present Example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings used for the following description, the dimensional ratios of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a diagram schematically showing a suspension structure in a power transmission device 10 for a vehicle to which a dynamic damper of the present invention is preferably applied. In the power transmission device 10 shown in FIG. 1, one end portion of the drive shaft 12 is connected to the differential device 16 on the transmission side via the constant velocity joint 14, and the other end portion is connected to the constant velocity joint 18. The motive power transmitted through the differential device 16 from an engine, a transmission, etc. (not shown) is connected to the drive wheels (wheels) 20 through the left and right movements from the drive wheels 20 and left and right by steering. It is configured to be transmitted to the drive wheel 20 in response to a change in angle caused by movement or the like. A dynamic damper 22 according to an embodiment of the present invention is provided on a part of the drive shaft 12.

  FIG. 2 is a cross-sectional view showing the configuration of the dynamic damper 22 of the present embodiment by cutting along a plane including the common shaft center C with the drive shaft 12. As shown in FIG. 2, the dynamic damper 22 is fixed to a part of the drive shaft 12 in a state where the drive shaft 12 penetrates, in other words, the axial center direction with respect to the drive shaft 12. These are attached so that they cannot move relative to each other and cannot rotate around the axis.

  The dynamic damper 22 includes a main body portion 24 that has a cylindrical shape whose inner diameter is larger than the outer diameter of the drive shaft 12, and fixed portions 26 that are fixed to the drive shaft 12 at both ends of the main body portion 24. It is configured with. The main body portion 24 and the fixing portion 26 are integrally formed from a material such as elastic rubber, for example. A weight portion 28 made of a metal material such as an iron material or a copper material having a predetermined mass is integrally embedded in the main body portion 24. A cylindrical space 34 corresponding to a gap between the dynamic damper 22 and the drive shaft 12 is formed between the inner peripheral surface 30 of the dynamic damper 22 and the outer peripheral surface 32 of the drive shaft 12.

  By being configured as described above, the dynamic damper 22 has a function of suppressing vibration of the drive shaft 12. In other words, the dynamic damper 22 is fixed (fixed) to the drive shaft 12 by the fixing portion 26, and relative movement with respect to the drive shaft 12 is impossible, while the weight portion 28 is embedded. Since the main body 24 is fixed to the drive shaft 12 via the elastic fixing portion 26, the vibration of the drive shaft 12 causes the main body 24 to move relative to the drive shaft 12. It is made to vibrate (resonate). Regarding the vibration of the main body 24, a resonance frequency (natural frequency) is determined so as to resonate when vibration is generated in the attached drive shaft 12, and the drive shaft 12 is resonated by the resonance of the main body 24. The vibration of the drive shaft 12 is suppressed by absorbing the vibration.

  FIG. 3 is a front view of FIG. 2 viewed from the direction indicated by arrow III. As shown in FIGS. 2 and 3, the dynamic damper 22 of the present embodiment has a plurality of (in FIG. 3, circumferentially spaced equidistant intervals) provided from the inner peripheral surface 30 of the dynamic damper 22 to the outer peripheral side. 6) through-holes 36 are provided. The through hole 36 is preferably provided on one end side in the axial direction of the dynamic damper 22 as shown in FIG. 2, for example, a boundary between the main body 24 and the fixing portion 26, that is, a cylinder. The inner peripheral surface 30 is formed by extending from one end to the outer peripheral side and extending in the diameter increasing direction. Further, preferably, as shown in FIG. 2 and the like, the diameter dimension of the through hole 36 is reduced (squeezed) from the inner peripheral side toward the outer peripheral side.

  As shown in FIG. 2, the inner circumferential surface 30 of the dynamic damper 22 preferably has an inner diameter that gradually decreases from the end on the side where the through hole 36 is provided to the other end. It is configured to be allowed to. Thereby, the cylindrical space 34 formed between the inner peripheral surface 30 of the dynamic damper 22 and the outer peripheral surface 32 of the drive shaft 12 is changed from the end side on the side where the through hole 36 is provided to the other side. The inner diameter dimension is gradually reduced toward the end side. In other words, the inner peripheral surface 30 of the dynamic damper 22 is a tapered surface in which the end on the side where the through hole 36 is provided is the large diameter side and the end on the opposite side is the small diameter side. .

  4 and 5 are partial cross-sectional views showing an enlarged portion of the dynamic damper 22 in order to explain the configuration around the through hole 36. FIG. 4 shows a state in which the through hole 36 is conducted. FIG. 5 shows a state in which the through hole 36 is closed. As shown in these drawings, a portion of the dynamic damper 22 corresponding to the opening on the inner peripheral side (the inner peripheral surface 30 side) of the through hole 36 is formed in the through hole 36 according to the rotational state of the drive shaft 12. There is provided a valve structure 38 for opening and closing. The valve structure 38 includes, for example, a protrusion 40 corresponding to a valve body that closes (closes) the through-hole 36 by bringing the tip side into contact with the inner peripheral surface 30 or the inner surface of the through-hole 36, and the like. A mass 42, which is a weight made of a material such as iron, provided at the tip of the protrusion 40 is provided. The protrusion 40 is preferably integrally formed from the same material as the fixing portion 26 with the inner peripheral surface (inner peripheral side wall) of the fixing portion 26 as a base end. In addition, preferably, the valve membrane is configured such that the thickness is gradually reduced from the fixed portion 26 side toward the inner peripheral surface 30 side.

  In the valve structure 38 configured as described above, when the drive shaft 12 is rotated, that is, when the drive shaft 12 is rotating (spinning) around the axis (or when the rotation speed is a predetermined value or more). ), The through hole 36 is closed as shown in FIG. 5 by the centrifugal force caused by the rotation of the drive shaft 12. That is, when a force in a radial direction (a direction away from the axis C of the drive shaft 12) is applied to the mass 42 provided at the tip of the protruding portion 40, the mass 42 moves to the inner peripheral surface. 30 or the inner surface of the through hole 36 and the like, and the through hole 36 is closed by the mass 42 and the protrusion 40. On the other hand, when the drive shaft 12 is not rotating, that is, when the drive shaft 12 is not rotating (rotating) around its axis, or when its rotational speed (rotational angular speed) is less than a predetermined value, the protrusion The tip or mass 42 is separated from the inner peripheral surface 30 or the inner surface of the through hole 36 by the elasticity of the portion 40, and the through hole 36 is conducted as shown in FIG. That is, in the dynamic damper 22 of the present embodiment, when the drive shaft 12 is driven, the valve structure 38 closes the through hole 36 and closes the cylindrical space 34 to the outside, while the drive shaft 12 During non-driving, the through hole 36 is conducted and the cylindrical space 34 is opened to the outside.

  For comparison with the dynamic damper 22 of the present embodiment, FIG. 6 shows a conventional dynamic damper 100 attached to the drive shaft 12 cut along a plane including a common axis C with the drive shaft 12. It is sectional drawing shown. In the dynamic damper 100 shown in FIG. 6, portions common to the dynamic damper 22 of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 6, the conventional dynamic damper 100 does not include the configuration of the through hole 36 and the valve structure 38, and therefore, for some reason, the inner peripheral surface of the dynamic damper 100 and the outer periphery of the drive shaft 12. If a foreign substance such as water enters between the surface, it is difficult to discharge the foreign substance to the outside. As such, if foreign matter such as water accumulates between the drive shaft 12 and the dynamic damper 100, the durability may be affected due to the progress of rust inside.

  On the other hand, according to the dynamic damper 22 of the present embodiment configured as described above with reference to FIGS. 2 to 5, when the drive shaft 12 is driven (rotated), due to the centrifugal force applied to the mass 42. The tip end of the protrusion 40 comes into contact with the inner peripheral surface 30 and the like, so that the cylindrical space 34 is separated from the outside, and entry of foreign matters such as water from the through hole 36 and the like is suppressed. Further, since the through hole 36 is formed by extending from the inner peripheral side to the outer peripheral side in the direction of increasing the diameter, foreign matters such as water in the through hole 36 are not moved when the drive shaft 12 is driven. Released to the outside by centrifugal force. Further, when the drive shaft 12 is not driven (not rotated), the mass 42 is not subjected to centrifugal force, whereby the through hole 36 is made conductive by the elasticity of the projection 40 and the dynamic damper 22 is The inner peripheral surface 30 is configured such that the inner diameter dimension is gradually reduced from the end portion on the side where the through-hole 36 is provided toward the other end portion, so that foreign matters such as water are caused by gravity. It is discharged to the outside through the through hole 36 along the inner peripheral surface 30. Accordingly, the foreign matter such as water is prevented from entering when the drive shaft 12 is driven, while the foreign matter is naturally discharged when the drive shaft 12 is not driven, and the deterioration of durability due to the occurrence of rust or the like can be suitably suppressed.

  As described above, according to the present embodiment, the through hole 36 penetrating from the inner peripheral surface 30 of the dynamic damper 22 to the outer peripheral side, and the centrifugal force when rotating around the axis of the drive shaft 12 A valve structure 38 that closes the through hole 36 and conducts the through hole 36 when not rotating is provided. Therefore, when the drive shaft 12 is rotated, the through hole 36 is closed to externally close the through hole 36. Intrusion of foreign matter can be suppressed while the through-hole 36 is made conductive during non-rotation. That is, it is possible to provide the vehicle drive shaft dynamic damper 22 that suppresses the entry of foreign matter into the interior.

  The through hole 36 is provided on one end side in the axial direction of the dynamic damper 22, and is between the inner peripheral surface 30 of the dynamic damper 22 and the outer peripheral surface 32 of the drive shaft 12. Since the cylindrical space 34 in which the inner diameter dimension is gradually reduced from the end side on the side where the through hole 36 is provided to the other end side is formed, the drive shaft 12 is not rotated. When the through-hole 36 is made conductive, the internal foreign matter is discharged to the outside through the inner peripheral surface 30 of the dynamic damper 22 due to gravity, and further preferably prevents the foreign matter from entering the dynamic damper 22. can do.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. Is.

  12: Drive shaft, 22: Dynamic damper, 30: Inner peripheral surface, 32: Outer peripheral surface, 34: Cylindrical space, 36: Through hole, 38: Valve structure

Claims (2)

A dynamic damper for a vehicle drive shaft, which is fixed to a part of the vehicle drive shaft in a state where the drive shaft penetrates and suppresses vibration of the drive shaft,
A through hole provided so as to penetrate from the inner peripheral surface of the dynamic damper to the outer peripheral side;
And a valve structure that closes the through-hole by centrifugal force when rotating about the axis of the drive shaft and that conducts the through-hole when not rotating. Dynamic damper.   The through hole is provided on one end side in the axial direction of the dynamic damper, and the through hole is provided between an inner peripheral surface of the dynamic damper and an outer peripheral surface of the drive shaft. The dynamic damper for a drive shaft of a vehicle according to claim 1, wherein a cylindrical space in which a diameter is gradually reduced from the side end portion toward the other end side is formed.

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