JP2010216579A - Dynamic damper and propeller shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the easiness of press-fitting of a dynamic damper into a hollow shaft and the drawing resistant load characteristic thereof while simplifying the formation of a rubber layer in the dynamic damper having the rubber layer on the outer periphery. <P>SOLUTION: In this dynamic damper 10, an outer pipe 20 includes outwardly extending parts 22 at a plurality of positions spaced in the circumferential direction of the cylinder, respectively. The outer periphery of the rubber layer 50 put on the outer peripheral surface of the outer pipe 20 is circular. The dynamic damper 10 is press-fitted into the circular hole of the hollow shaft 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dynamic damper and a propeller shaft.

  As described in Patent Documents 1 and 2, an outer pipe and an outer pipe are used as dynamic dampers that are press-fitted into a straight circular hole in the axial direction of a hollow propeller shaft to reduce vibration of the propeller shaft and reduce vehicle body vibration and noise. And a rubber layer that is attached to the outer peripheral surface of the outer pipe, and a weight disposed inside the outer pipe.

  The dynamic damper can be easily inserted into the hole of the hollow shaft by elastic deformation of the rubber layer, and can be fixed by being pressed into the hole by the elastic force of the rubber layer.

JP 3-288041 A Japanese Patent Laid-Open No. 9-1762

  In the dynamic damper described in Patent Document 1, a rubber layer having a constant thickness is continuously formed on the entire outer periphery of the cylindrical outer pipe. At this time, if the compression ratio of the rubber layer when the dynamic damper is press-fitted into the hollow propeller shaft is increased so as to increase the pressure of the rubber layer against the hollow propeller shaft, the compression ratio of the rubber layer is increased over the entire circumference of the outer pipe. However, it becomes difficult to press-fit the dynamic damper together with variations in the inner diameter tolerance of the hollow propeller shaft. Conversely, when the compression ratio of the rubber layer is lowered, the pressure contact force of the rubber layer against the hollow propeller shaft is lowered, and the rubber layer is resistant to large acceleration, vibration, and torsion due to the rotational speed of the hollow propeller shaft, sudden torque fluctuations, etc. The drop-out load resistance characteristics for the hollow propeller shaft are reduced.

  In the dynamic damper described in Patent Document 2, since the rubber layer is partially formed at a plurality of locations on the outer peripheral surface of the cylindrical outer pipe, the compression rate of the rubber layer is not increased over the entire circumference of the outer pipe. Although the press contact force of the rubber layer with respect to the hollow propeller shaft can be ensured at the portion having the high compression ratio while the press fitting is facilitated, the slip resistance can be improved, but there is a difficulty in forming the rubber layer portion.

  In the dynamic damper described in Patent Document 2, an elastic body is disposed in an annular space between the outer pipe and the weight, and an outer peripheral layer bonded to the inner surface of the outer pipe, an inner peripheral layer bonded to the outer surface of the weight, It is composed of elastic interposing portions provided at a plurality of positions in the circumferential direction between the layer and the inner peripheral layer, and a through-hole is provided between adjacent elastic interposing portions. Each elastic interposing part of the elastic body is disposed opposite to the cylindrical inner surface of the outer pipe between the outer pipe and the weight. Therefore, when the diameters of the outer pipe and the weight are determined in relation to the inner diameter of the hollow propeller shaft and the like, the distance between the outer pipe and the weight that supports both ends of each elastic interposing part via the outer peripheral layer and the inner peripheral layer of the elastic body (Substantially both end support length L of each elastic intervention part) is uniquely determined, and the vibration function of the weight with respect to the outer pipe, that is, the resonance frequency of the dynamic damper, which is a damper function provided by the elastic intervention part. There are difficulties in tuning.

  In addition, each elastic interposition part is only arranged to be opposed to and supported by the inner surface of the outer pipe having a constant curvature, and the support structure of each elastic interposition part by the outer pipe has no particular stability, and It is difficult to improve the durability of each elastic intervention part carrying the weight.

  SUMMARY OF THE INVENTION An object of the present invention is to improve the press-fitting property and anti-slip load characteristics of a dynamic damper to a hollow shaft while simplifying the formation of the rubber layer in a dynamic damper having a rubber layer provided on the outer periphery.

  Another object of the present invention is to increase the adjustment range for tuning the resonance frequency of the dynamic damper, and also to improve the durability of each elastic interposing part carrying a weight with respect to the outer pipe. .

  The invention according to claim 1 includes an outer pipe, a weight disposed inside the outer pipe, an elastic body interposed between the outer pipe and the weight, and a rubber layer attached to the outer peripheral surface of the outer pipe. In the dynamic damper, the outer pipe is provided with outwardly extending portions at intervals in the circumferential direction of the cylinder, the outer diameter of the rubber layer attached to the outer peripheral surface of the outer pipe is circular, and the dynamic pipe A damper is used by being press-fitted into a circular hole of a hollow shaft.

  According to a second aspect of the invention, in the first aspect of the invention, the elastic body is disposed in an annular space between the outer pipe and the weight, and is bonded to the outer surface of the outer pipe and the outer peripheral layer bonded to the inner surface of the outer pipe. It is composed of an inner circumferential layer and elastic interposed portions provided at a plurality of positions in the circumferential direction between the outer circumferential layer and the inner circumferential layer, and a through-hole is provided between adjacent elastic interposed portions. Is.

  According to a third aspect of the present invention, in the second aspect of the present invention, the elastic interposing part of the elastic body is arranged to be opposed to the inner surface concave part of the projecting part of the outer pipe.

  According to a fourth aspect of the present invention, in the second aspect of the present invention, the elastic interposing portions of the elastic body and the overhanging portions of the outer pipe are alternately arranged in the circumferential direction.

  The invention according to claim 5 is a propeller shaft in which the dynamic damper according to any one of claims 1 to 4 is press-fitted into a hollow shaft and fixedly arranged.

(Claims 1 and 2)
(a) When a rubber layer is attached to the entire outer peripheral surface of the outer pipe, the rubber layer corresponding to the outer convex portion of the overhanging portion of the outer pipe is made thinner than the thickness of the other portions, and the dynamic damper When pressed into the hollow shaft, the compression ratio becomes higher than the compression ratio of the other portions. Therefore, by simply applying the rubber layer to the entire circumference of the outer pipe, the formation of the rubber layer is simplified, the compression rate of the rubber layer is not increased over the entire circumference of the outer pipe, and the dynamic damper is easily pressed. The pressure contact force of the rubber layer to the hollow shaft can be ensured at the portion of the high compression ratio, and the press-fit property and the slip-out resistance of the dynamic damper to the hollow shaft can be improved.

(Claim 3)
(b) The elastic interposing part of the elastic body carrying the weight with respect to the outer pipe is arranged opposite to the inner surface concave part of the projecting part of the outer pipe. Therefore, when the diameters of the outer pipe and the weight are determined in relation to the inner diameter and the like of the hollow shaft, the distance between the outer pipe and the weight that supports both ends of each elastic interposing part via the outer peripheral layer and the inner peripheral layer of the elastic body ( The substantially both-end support length L) of each elastic intervention part can be adjusted by setting the depth h of the inner surface recess of the overhanging part of the outer pipe. Can be tuned.

  (c) The inner surface recesses in which each elastic interposing part is supported by being opposed to and supported by the inner surface recess of the projecting part of the outer pipe via an outer peripheral layer, and the circumferential length of the inner surface of the cylinder is increased by the depression. Adhesion is supported over a large adhesion length (support length). Therefore, it is possible to improve the stability of the weight support structure in the circumferential direction and the radial direction of each elastic interposition part by the outer pipe, and to improve the durability reliability of each elastic interposition part carrying the weight with respect to the outer pipe.

(Claim 4)
(d) The elastic interposing portions of the elastic body carrying the weight with respect to the outer pipe and the overhanging portions of the outer pipe are alternately arranged in the circumferential direction. When the dynamic damper is press-fitted into the hollow shaft, the rubber layer corresponding to the overhanging portion of the outer pipe is compressed with a high compression ratio, and does not act directly on the elastic intercalation portion of the elastic body. The original damper function provided by the intervening portion (weight vibration characteristics with respect to the outer pipe) can be sufficiently exhibited.

(Claim 5)
(e) In the propeller shaft, the above (a) to (d) can be realized.

1A and 1B show a dynamic damper, where FIG. 1A is a front view and FIG. 1B is a cross-sectional view taken along line BB. FIG. 2 is an enlarged front view showing the dynamic damper.

  The dynamic damper 10 of FIG. 1 is press-fitted into a predetermined position in the axial direction in a circular hole straight in the axial direction of the hollow shaft 2 of the propeller shaft 1 for an automobile, and is fixedly arranged. The dynamic damper 10 reduces the vibration of the propeller shaft 1 and reduces vehicle body vibration and noise.

  The dynamic damper 10 includes an outer pipe 20, a weight 30, an elastic body 40, and a rubber layer 50.

  The outer pipe 20 has a cylindrical shape as described later, and is formed of a wound pipe made of a metal plate such as a spring steel plate or a hollow pipe of a metal tube such as a steel pipe.

  The weight 30 has a short column shape such as a cylinder and is made of a metal bar such as a steel bar. The weight 30 is disposed concentrically with the outer pipe 20 inside the outer pipe 20. The weight 30 is wider than the outer pipe 20.

  The elastic body 40 is disposed in the annular space 11 between the outer pipe 20 and the weight 30, an outer peripheral layer 41 bonded to the inner surface of the outer pipe 20, an inner peripheral layer 42 bonded to the outer surface of the weight 30, and an outer peripheral layer 41 and an elastic interposing portion 43 provided at a plurality of circumferential positions (5 positions in the present embodiment) between the inner circumferential layer 42 and the inner circumferential layer 42. The outer peripheral layer 41 and the inner peripheral layer 42 have substantially the same width as the outer pipe 20. The elastic interposing portion 43 is narrower than the outer peripheral layer 41 and the inner peripheral layer 42 and is erected at the center in the width direction of the outer peripheral layer 41 and the inner peripheral layer 42. The elastic body 40 is provided with a penetrating cavity 44 between adjacent elastic intervention parts 43, 43. The elastic body 40 is made of synthetic rubber or the like, and is integrally vulcanized with the outer pipe 20 and the weight 30.

  The rubber layer 50 is attached to the outer peripheral surface of the outer pipe 20. The rubber layer 50 has an outer diameter that is straight in the axial direction, has a cylindrical shape having an outer diameter larger than the hole diameter of the hollow shaft 2, and is inserted into the hole of the hollow shaft 2 by being press-fitted into the dynamic damper 10. Is fixed at a predetermined position in the axial direction by the elastic force and friction of the rubber layer 50 against the hole of the hollow shaft 2.

  However, as shown in FIG. 2, the dynamic damper 10 has a plurality of locations (five locations in the present embodiment) that are spaced apart in the circumferential direction of the cylinder in which the outer pipe 20 has a perfect circle portion 21 that forms a substantially perfect circle. An outer projecting portion 22 is provided on the outer pipe 20, and the outer diameter of the rubber layer 50 attached to the outer peripheral surface of the outer pipe 20 is circular. In the present embodiment, the outer pipe 20 divides the cylindrical perfect circle portion 21 into five so as to make equal intervals in the circumferential direction, and forms an outwardly gently convex convex curve between the divided perfect circle portions 21. Thus, five overhanging portions 22 forming ridges were provided. Each overhang portion 22 is a projecting symmetric line with respect to the center line of the overhang portion 22 located on the diameter passing through the center of the dynamic damper 10 (the center of the outer pipe 20, the weight 30, the elastic body 40, and the rubber layer 50). Make.

  Further, in the dynamic damper 10, each elastic interposing portion 43 of the elastic body 40 is disposed to face the inner surface concave portion 22 </ b> A of each overhang portion 22 of the outer pipe 20. That is, the center line of the elastic intervention part 43 located on the diameter passing through the center line of the dynamic damper 10 of each elastic intervention part 43 matches the center line of each overhanging part 22 of the outer pipe 20, and each elastic intervention part 43. The portion 43 is disposed so as to face the central portion in the circumferential direction of the inner surface recess 22 </ b> A of each overhang portion 22 of the outer pipe 20. The outer end portion of each elastic interposing portion 43 is supported by the inner surface concave portion 22A of each overhanging portion 22 via the outer peripheral layer 41 of the elastic body 40, and the outer peripheral layer 41 of the elastic body 40 is supported by the inner surface concave portion 22A of each overhanging portion 22. The portion to be bonded is made into a mountain shape (convex shape) protruding outward from the other portions. The outer peripheral layer 41 of the elastic body 40 may be disposed with a constant thickness with respect to the inner peripheral surface of the outer pipe 20 along the inner surface recess 22A of each overhanging portion 22 of the outer pipe 20. In this case, each elastic interposition part 43 can be formed with a longer abutting (outer end part) position with the outer peripheral layer 41, so that the tuning width of each elastic interposition part 43 is widened. The inner end portion of each elastic interposing portion 43 supports the weight 30 via the inner peripheral layer 42 of the elastic body 40.

  The dynamic damper 10 is vulcanized by injecting rubber and integrally forming the elastic body 40 and the rubber layer 50 in a state where the outer pipe 20 and the weight 30 are disposed in the mold.

Therefore, according to the dynamic damper 10 of the present embodiment, there are the following functions and effects.
(a) When the rubber layer 50 is attached to the entire outer peripheral surface of the outer pipe 20, the thickness of the rubber layer 50 corresponding to the outer convex portion 22B of the overhanging portion 22 of the outer pipe 20 is larger than the thickness of other portions. When the dynamic damper 10 is press-fitted into the hollow shaft 2, the compression ratio is made higher than the compression ratios of the other portions. Therefore, by applying the rubber layer 50 to the entire circumference of the outer pipe 20, the formation of the rubber layer 50 is simplified, and the compression rate of the rubber layer 50 is not increased over the entire circumference of the outer pipe 20. The press contact force of the rubber layer 50 with respect to the hollow shaft 2 can be secured at the portion having a high compression rate while facilitating the press fitting, and the press fit property and the anti-drop load characteristic of the dynamic damper 10 with respect to the hollow shaft 2 can be improved.

  (b) The elastic interposing portion 43 of the elastic body 40 carrying the weight 30 with respect to the outer pipe 20 is disposed so as to face the inner surface concave portion 22 </ b> A of the overhang portion 22 of the outer pipe 20. Therefore, when the diameters of the outer pipe 20 and the weight 30 are determined in relation to the inner diameter of the hollow shaft 2, both ends of each elastic interposing portion 43 are supported via the outer peripheral layer 41 and the inner peripheral layer 42 of the elastic body 40. The distance between the outer pipe 20 and the weight 30 (substantial both-end support length L of each elastic interposing portion 43) can be adjusted by setting the depth h of the inner surface recess 22A of the overhanging portion 22 of the outer pipe 20, The vibration characteristics of the weight 30 and thus the resonance frequency of the dynamic damper 10 can be tuned over a wide range.

  (c) Each elastic interposing portion 43 is supported by being opposed to and supported by the inner surface concave portion 22A of the overhanging portion 22 of the outer pipe 20 via the outer peripheral layer 41, and further, the circumferential length of the inner surface of the cylinder is recessed. The elongated inner surface recess 22A is bonded and supported over a large bonding length (support length) and is engaged with and bonded to the inner surface recess 22A. Accordingly, it is possible to improve the stability of the support structure by the outer pipe 20 of each elastic interposition part 43 and to improve the durability of each elastic interposition part 43 carrying the weight 30 with respect to the outer pipe 20.

  (d) In the propeller shaft 1, the above-described (a) to (c) can be realized.

  In the modified example of the dynamic damper 10, the elastic interposed portions 43 of the elastic body 40 and the overhang portions 22 of the outer pipe 20 may be alternately arranged in the circumferential direction. That is, the center line of each elastic interposition part 43 passes through the central part in the circumferential direction of the perfect circle part 21 sandwiched by the adjacent overhanging parts 22 of the outer pipe 20, and each elastic interposition part 43 is adjacent to the outer pipe 20. It is arranged to be opposed to the central portion in the circumferential direction of the perfect circle portion 21 sandwiched between the overhang portions 22.

  According to this modification, the elastic interposing portions 43 of the elastic body 40 carrying the weights 30 with respect to the outer pipe 20 and the overhang portions 22 of the outer pipe 20 are alternately arranged in the circumferential direction. When the dynamic damper 10 is press-fitted into the hollow shaft 2, even if the outer pipe 20 is deformed inward due to a large pressure contact force that is compressed at a high compression ratio, the rubber layer 50 corresponding to the overhanging portion 22 of the outer pipe 20 is directly elastic. The original damper function (vibration characteristics of the weight 30 with respect to the outer pipe 20) provided by the elastic interposing part 43 can be sufficiently exhibited without acting on the elastic interposing part 43 of the body 40.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, the outer pipe 20 and / or the weight 30 can be completely covered with the elastic body 40 or the rubber layer 50. Thereby, a rust prevention process can also be abolished.

  According to the present invention, an outer pipe is provided with outward projecting portions at a plurality of positions in the circumferential direction of a cylinder, and an outer diameter of a rubber layer attached to the outer peripheral surface of the outer pipe is circular, and the dynamic damper Is used by being press-fitted into a circular hole of the hollow shaft. Therefore, in the dynamic damper having the rubber layer provided on the outer periphery, it is possible to improve the press-fitting property and the slip-proof load resistance characteristic of the dynamic damper to the hollow shaft while simplifying the formation of the rubber layer. In addition, the tuning range of the resonance frequency of the dynamic damper can be widened, and the durability reliability of each elastic interposing part carrying the weight with respect to the outer pipe can be improved.

DESCRIPTION OF SYMBOLS 1 Propeller shaft 2 Hollow shaft 10 Dynamic damper 20 Outer pipe 22 Overhang | projection part 22A Inner surface recessed part 22B Outer surface convex part 30 Weight 40 Elastic body 41 Outer peripheral layer 42 Inner peripheral layer 43 Elastic interposition part 44 Through-like cavity part 50 Rubber layer

Claims (5)

In a dynamic damper having an outer pipe, a weight disposed inside the outer pipe, an elastic body interposed between the outer pipe and the weight, and a rubber layer attached to the outer peripheral surface of the outer pipe,
Outer pipes are provided with outward projecting portions at intervals in the circumferential direction of the cylinder, the outer diameter of the rubber layer attached to the outer peripheral surface of the outer pipe is circular, and the dynamic damper is provided with a hollow shaft. A dynamic damper that is used by being press-fitted into a circular hole.   The elastic body is disposed in an annular space between the outer pipe and the weight, and an outer peripheral layer bonded to the inner surface of the outer pipe, an inner peripheral layer bonded to the outer surface of the weight, and a circumference between the outer peripheral layer and the inner peripheral layer. 2. The dynamic damper according to claim 1, wherein the dynamic damper is composed of elastic interposed portions provided at a plurality of positions in the direction, and a through-hole is provided between adjacent elastic interposed portions.   The dynamic damper according to claim 2, wherein the elastic interposing portion of the elastic body is disposed to face the inner surface concave portion of the projecting portion of the outer pipe.   The dynamic damper according to claim 2, wherein the elastic interposing portions of the elastic body and the overhanging portions of the outer pipe are alternately arranged in the circumferential direction.   A propeller shaft in which the dynamic damper according to any one of claims 1 to 4 is press-fitted into a hollow shaft and fixedly arranged.

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