JP2020159397A - Dynamic damper - Google Patents

Abstract

To provide a dynamic damper usable in a low frequency region without complication of a configuration and limitation of revolution in operation.SOLUTION: In a compression and tension type dynamic damper 1 including a cylindrical part 2 made of elastomer to be inserted into an outer periphery of a propeller shaft (rotational axis) 10, a circular weight 3 arranged concentrically from the cylindrical part 2 outward in a radial direction with a predetermined distance, and a circular connection part 4 formed integrally with the cylindrical part 2 to connect the cylindrical part 2 and the weight 3 in the radial direction, the cylindrical part 2 and the weight 3 are connected with plural ribs 5 radially arranged therebetween. Each of the ribs 5 is formed integrally with the cylindrical part 2 and the connection part 4. And, each of the ribs 5 is a rectangular solid, and its length A in the radial direction and its length B in a rotation direction are set to a ratio A/B≥1.SELECTED DRAWING: Figure 3

Description

The present invention relates to a compression / tension type dynamic damper mounted on a rotating shaft to suppress vibration of the rotating shaft.

For example, a rotating shaft such as a propeller shaft of a vehicle is equipped with a dynamic damper (dynamic vibration absorber) for suppressing the rotational vibration of the rotating shaft. This dynamic damper suppresses a resonance phenomenon around the natural frequency of the rotating shaft. For example, from a cylindrical portion made of an elastic body such as rubber fitted on the outer circumference of the rotating shaft, and from the cylindrical portion. A ring-shaped weight that is concentrically arranged radially outward by a predetermined distance, and a ring-shaped connecting portion that is integrally formed with the cylindrical portion and connects the cylindrical portion and the weight in the radial direction. It is composed including and.

Such dynamic dampers include a compression / tension type that mainly absorbs radial vibration of the rotating shaft by compression / tension deformation of a connecting portion made of an elastic body such as rubber (see, for example, Patent Document 1). There is a shear type (see, for example, Patent Document 2) that mainly absorbs axial vibration due to shear deformation of the connecting portion.

By the way, in Patent Document 3, a semicircular cross section is provided on the inner wall of the through hole of the cylindrical portion of the dynamic damper so that foreign matter that has entered between the cylindrical portion of the dynamic damper and the rotating shaft can be easily discharged. A configuration has been proposed in which a plurality of discharge grooves are provided along the axial direction.

Japanese Unexamined Patent Publication No. 9-229137 Japanese Unexamined Patent Publication No. 2001-349379 Japanese Unexamined Patent Publication No. 2011-012709

By the way, in a compression / tension type dynamic damper, the hardness (rubber hardness) of the connecting portion may be lowered (softened) to use the dynamic damper in a low frequency range. In such a case, if there is a radial deviation (eccentricity) in the axial center of the weight, the amount of radial deformation of the connecting portion due to the centrifugal force acting on the weight during high-speed rotation of the rotating shaft becomes partially large. Therefore, there is a problem that the dynamic damper cannot withstand use. In order to solve such a problem, it is necessary to take measures such as suppressing the amount of radial deformation of the connecting portion of the dynamic damper by a stopper and lowering the rotation speed of the rotating shaft.

However, if the stopper is provided as described above, there arises a problem that the structure of the dynamic damper becomes complicated and the cost increases. Further, if the rotation speed of the rotating shaft is lowered in order to suppress the amount of radial deformation of the connecting portion of the dynamic damper, the usable range of the device provided with such a rotating shaft is narrowed, and the versatility of the device is lowered. There is a problem.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a dynamic damper that can be used in a low frequency range without complicating the structure or limiting the number of revolutions used. ..

In order to achieve the above object, the first invention presents a cylindrical portion (2) made of an elastic body fitted on the outer circumference of a rotating shaft (10) and a predetermined distance radially outward from the cylindrical portion (2). A ring-shaped weight (3) arranged concentrically apart from each other and a ring formed integrally with the cylindrical portion (2) and connecting the cylindrical portion (2) and the weight (3) in the radial direction. A compression / tension type dynamic damper (1) including a shaped connecting portion (4), and the cylindrical portion (2) and the weight (3) are arranged radially between the two. It is characterized in that it is connected by a plurality of ribs (5).

According to the dynamic damper according to the first invention, since a plurality of ribs are radially arranged in the ring-shaped space formed between the cylindrical portion and the weight in the radial direction, the rotating shaft mainly vibrates in the radial direction. The radial rigidity (spring constant) of the connecting portion that absorbs the water is increased by the plurality of ribs. Therefore, when the hardness (rubber hardness) of the connecting portion of the dynamic damper is lowered (softened) and the dynamic damper is used in the low frequency range, there is a radial deviation (eccentricity) in the axial center of the weight. Even so, the amount of elastic deformation in the radial direction of the connecting portion due to the centrifugal force acting on the weight when the rotating shaft rotates at high speed is suppressed to a small value, and the dynamic damper can sufficiently withstand the use of high rotation. As a result, the number of rotations of the rotating shaft on which the dynamic damper is mounted is not limited. Since such an effect can be obtained by a simple configuration in which a plurality of ribs are arranged on the dynamic damper, the structure of the dynamic damper is not complicated and the cost is not increased.

Further, in the dynamic damper (1) according to the first invention, three or more ribs (5) may be arranged. Then, an odd number of ribs (5) may be arranged.

According to this configuration, the balance of the radial rigidity (spring constant) of the connecting portion that mainly absorbs the rotational vibration in the radial direction can be well maintained by a plurality of ribs of three or more.

Further, in the dynamic damper (1) according to the first invention, each rib (5) may be formed integrally with the cylindrical portion (2) and the connecting portion (4).

According to the above configuration, each rib made of an elastic body can be easily formed by integrally molding with a cylindrical portion and a connecting portion also made of an elastic body.

Further, in the dynamic damper (1) according to the first invention, each rib (5) is a rectangular parallelepiped, and the ratio A / B of the radial length A and the rotational length B is
A / B ≧ 1
It may be set to.

According to the above configuration, the ribs can mainly increase the rigidity (spring constant) in the radial direction without increasing the rigidity of the connecting portion in the rotational direction. Therefore, the amount of elastic deformation in the radial direction at high rotation of the connecting portion of the dynamic damper can be suppressed to a small value without significantly affecting the vibration absorption performance in the rotation direction of the dynamic damper.

Further, in the second invention, the cylindrical portion (2) made of an elastic body fitted on the outer circumference of the rotating shaft (10) is concentrically separated from the cylindrical portion (2) by a predetermined distance outward in the radial direction. A ring-shaped connecting portion (3) arranged in a ring-shaped weight (3) and a ring-shaped connecting portion (2) formed integrally with the cylindrical portion (2) to connect the cylindrical portion (2) and the weight (3) in the radial direction. 4) is a compression / tension type dynamic damper (1') including the above, and a plurality of radial core materials (6) are radially embedded in the connecting portion (4). , At least one end in the longitudinal direction of each core material (6) is not in contact with the cylindrical portion (2) or the weight (3).

According to the dynamic damper according to the second invention, since a plurality of radial core members are radially embedded in the connecting portion, the radial rigidity of the connecting portion that mainly absorbs the radial vibration of the rotating shaft ( (Spring constant) is enhanced by multiple core materials. Therefore, when the hardness (rubber hardness) of the connecting portion of the dynamic damper is lowered (softened) and the dynamic damper is used in the low frequency range, there is a radial deviation (eccentricity) in the axial center of the weight. Even in this state, the amount of elastic deformation in the radial direction of the connecting portion due to the centrifugal force acting on the weight when the rotating shaft rotates at high speed is suppressed to a small extent, and the dynamic damper can sufficiently withstand the use of high rotation. As a result, the number of rotations of the rotating shaft on which the dynamic damper is mounted is not limited. Since such an effect can be obtained by a simple configuration in which a plurality of core materials are embedded in the connecting portion of the dynamic damper, the structure of the dynamic damper is not complicated and the cost is not increased.

Further, in the dynamic damper (1') according to the second invention, three or more core materials (6) may be arranged. Then, an odd number of core materials (6) may be arranged.

According to this configuration, the balance of the radial rigidity (spring constant) of the connecting portion that mainly absorbs the rotational vibration in the radial direction can be well maintained by a plurality of three or more core materials.

According to the dynamic damper according to the present invention, it can be used in a low frequency range without complicating the structure or limiting the rotation speed.

It is a side sectional view which shows the structure of the power transmission system main part of the vehicle which includes the dynamic damper which concerns on this invention. It is a perspective view of the dynamic damper which concerns on 1st invention. It is an enlarged detailed view of part X of FIG. It is a front view of the dynamic damper which concerns on 1st invention. FIG. 4 is a cross-sectional view taken along the line YY of FIG. It is a front view of the dynamic damper which concerns on 2nd invention. FIG. 6 is a cross-sectional view taken along the line ZZ of FIG. (A) and (b) are the same views as FIG. 7 showing another embodiment of the second invention.

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

First, an example of using the dynamic damper according to the present invention will be described with reference to FIG. That is, FIG. 1 is a side sectional view showing a configuration of a main part of a power transmission system of a vehicle provided with a dynamic damper according to the present invention. In FIG. 1, 10 extends along a vehicle front-rear direction (horizontal direction in FIG. 1). It is a propeller shaft as a rotating shaft.

The front end (left end of FIG. 1) of the propeller shaft 10 is connected to the output shaft of a transmission (not shown) by a universal joint (universal joint) 11, and the rear end is a differential device (difference) not shown by a universal joint 12. It is connected to the moving device). The longitudinal intermediate portion of the propeller shaft 10 is rotatably supported by a vehicle body (not shown) by a center support 13, and the outer periphery between the center support 13 and the rear universal joint 12 according to the present invention. Dynamic damper 1 (1') is installed.

Next, embodiments of the dynamic dampers 1, 1'according to the first invention and the second invention will be described.

[First invention]
2 is a perspective view of the dynamic damper according to the first invention, FIG. 3 is an enlarged detailed view of part X of FIG. 2, FIG. 4 is a front view of the dynamic damper, and FIG. 5 is a sectional view taken along line YY of FIG. , The illustrated dynamic damper 1 is a compression / tension type.

The dynamic damper 1 according to the first invention is concentrically arranged with a cylindrical portion 2 fitted on the outer periphery of the propeller shaft 10 shown in FIG. 1 at a distance of a predetermined distance outward from the cylindrical portion 2 in the radial direction. It is composed of a ring-shaped weight 3 and a ring-shaped connecting portion 4 that is integrally formed with the cylindrical portion 2 and connects the cylindrical portion 2 and the weight 3 in the radial direction. Here, the cylindrical portion 2 and the connecting portion 4 are integrally formed of an elastic body such as rubber, and the weight 3 is made of metal. In the actual production of the dynamic damper 1, the cylindrical portion 2, the weight 3, and the connecting portion 4 are integrally molded by vulcanization molding of an elastic body such as rubber.

By the way, in the dynamic damper 1 according to the present embodiment, as shown in FIGS. 2 and 4, a plurality of cylindrical portions 2 and weights 3 are radially arranged between the two (five in the illustrated example). ) Are connected to each other by ribs 5. In other words, in the ring-shaped space formed between the cylindrical portion 2 and the weight 3 in the radial direction of the dynamic damper 1, five ribs 5 radiate at an equal angle pitch (72 ° pitch) in the circumferential direction. Have been placed. More specifically, as shown in FIG. 5, the width (axial length) w1 of the connecting portion 4 is smaller than the width W of the cylindrical portion 2 and the weight 3 (w1 <W), and each rib 5 is connected. Five of each of the portions 4 are arranged on both sides in the axial direction (left and right in FIG. 5), the width w2 thereof is w2 = (W-w1) / 2, and in the present embodiment, each rib 5 is made of rubber. It is integrally formed with the cylindrical portion 2 and the connecting portion 4 by an elastic body such as.

Here, as shown in detail in FIG. 3, each rib 5 is configured as a rectangular parallelepiped, and the ratio A / B of the radial length A and the rotational length B is
A / B ≧ 1
Is set to. In this embodiment, A / B = 5 is set.

The dynamic damper 1 configured as described above is mounted on the outer periphery of the propeller shaft 10 by fitting the cylindrical portion 2 on the outer periphery of the propeller shaft 10 shown in FIG. 1, and rotates together with the propeller shaft 10. The weight 3 also vibrates due to the rotational vibration of the propeller shaft 10. Then, the connecting portion 4 is elastically deformed by repeating compression and tension due to the vibration mainly in the radial direction of the weight 3, and the vibration mainly in the radial direction of the propeller shaft 10 is absorbed by the elastic deformation of the connecting portion 4. In this case, the vibration absorption characteristic of the dynamic damper 1 can be changed by changing the weight of the weight 3. In the dynamic damper 1, the vibration in the rotation direction of the propeller shaft 10 is absorbed by the elastic deformation of the connecting portion 4 in the rotation direction (circumferential direction).

By the way, in the dynamic damper 1 according to the present embodiment, a plurality of (5) rectangular parallelepiped ribs 5 are radially formed in a ring-shaped space formed between the cylindrical portion 2 and the weight 3 in the radial direction. Therefore, the radial rigidity (spring constant) of the connecting portion 4 that mainly absorbs the radial vibration of the propeller shaft 10 (see FIG. 1) is enhanced by the plurality of ribs 5. Therefore, when the hardness (rubber hardness) of the connecting portion 4 of the dynamic damper 1 is lowered (softened) and the dynamic damper 1 is used in a low frequency range, a radial deviation (eccentricity) is made in the axial center of the weight 3. ) Is present, the amount of elastic deformation in the radial direction of the connecting portion 4 due to the centrifugal force acting on the weight 3 during high-speed rotation of the propeller shaft 10 is suppressed to a small value, and the dynamic damper 1 is sufficient for high-speed use. Can withstand. As a result, the rotation speed of the propeller shaft to which the dynamic damper 1 is mounted is not limited. Since such an effect can be obtained by simply providing the dynamic damper 1 with a plurality of ribs 5 by integrally molding the cylindrical portion 2 and the connecting portion 4 made of an elastic body, the structure of the dynamic damper 1 is complicated. It does not lead to conversion or cost increase.

Then, in the present embodiment, each rib 5 is configured as a rectangular parallelepiped, and the ratio A / B of the radial length A and the rotational length B is set to about A / B = 5, so that these ribs With 5, the rigidity in the radial direction (spring constant) can be mainly increased without significantly increasing the rigidity in the rotational direction of the connecting portion 4. Therefore, the amount of elastic deformation in the radial direction of the connecting portion 4 of the dynamic damper 1 at high rotation can be suppressed to a small value without significantly affecting the vibration absorption performance of the dynamic damper 1 in the rotational direction.

Further, in the dynamic damper 1 according to the present embodiment, since the five ribs 5 which are an odd number are arranged radially at an equal angle pitch (72 ° pitch) in the circumferential direction, the rotational vibration in the radial direction is mainly absorbed. A good balance of radial rigidity (spring constant) of the connecting portion 4 can be maintained. In the dynamic damper 1 according to the present embodiment, five ribs 5 are arranged at equal angles in the circumferential direction, but the number of ribs 5 is not limited to five and may be an odd number of three or more. , The balance of the radial rigidity (spring constant) of the connecting portion 4 can be kept good.

[Second invention]
Next, an embodiment of the second invention will be described below with reference to FIGS. 6 and 7.

6 is a front view of the dynamic damper according to the second invention, FIG. 7 is a sectional view taken along line ZZ of FIG. 6, and in these figures, the same elements as those shown in FIGS. 2 to 5 are the same. The reference numerals are given, and the description thereof will be omitted below.

In the dynamic damper 1'according to the second invention, a plurality of (five in this embodiment) core members 6 such as wires long in the radial direction are connected to the connecting portion 4 at an equal angle pitch (72 ° pitch) in the circumferential direction. The one end in the longitudinal direction (outer end in the radial direction) of each core material 6 is brought into contact with the inner peripheral surface of the weight 3 as shown in FIG. 7, and the other end in the longitudinal direction (inner end in the radial direction) is a cylindrical portion. It is characterized in that it is separated from the outer peripheral surface of 2 and is not in contact with the cylindrical portion 2, and other configurations are the same as those of the dynamic damper 1 according to the first invention. In the actual production of the Dynemic damper 1'according to the second invention, a plurality of core materials 6 are radially preset in the portion where the connecting portion 4 of the molding die is molded, and the rubber using this molding die is used. The dynamic damper 1'is manufactured by vulcanization molding of an elastic body such as the above, and a plurality of core materials 6 are embedded inside the connecting portion 4 of the dynamic damper 1'manufactured in this way. Become.

The dynamic damper 1'configured as described above is mounted on the outer periphery of the propeller shaft 10 by fitting the cylindrical portion 2 on the outer periphery of the propeller shaft 10 shown in FIG. 1, and rotates together with the propeller shaft 10. As a result, similarly to the dynamic damper 1 according to the first invention, the connecting portion 4 is elastically deformed by repeating compression and tension due to the radial vibration of the weight 3, and the elastic deformation of the connecting portion 4 mainly causes the propeller shaft 10 to be elastically deformed. The radial vibration is absorbed.

Then, in the dynamic damper 1'according to the present embodiment, a plurality of core members 6 (five in the present embodiment) such as wires long in the radial direction are connected to the connecting portion 4 at an equal angle pitch in the circumferential direction (in the present embodiment). Since the propeller shaft 10 (see FIG. 1) is buried radially at a pitch of 72 °), the radial rigidity (spring constant) of the connecting portion 4 that mainly absorbs the radial vibration is enhanced by the plurality of core members 6. .. Therefore, when the hardness (rubber hardness) of the connecting portion 4 of the dynamic damper 1'is lowered (softened) and the dynamic damper 1'is used in a low frequency range, the weight 3 is displaced in the radial direction. Even in the presence of (eccentricity), the amount of elastic deformation in the radial direction of the connecting portion 4 due to the centrifugal force acting on the weight 3 during high-speed rotation of the propeller shaft 10 is suppressed to a small value, and the dynamic damper 1'rotates at high speed. Can withstand the use of. As a result, the rotation speed of the propeller shaft 10 to which the dynamic damper 1'is mounted is not limited. Since such an effect can be obtained by a simple configuration in which a plurality of core materials are embedded in the connecting portion 4 of the dynamic damper 1', the structure of the dynamic damper 1'is complicated and the cost is increased. Never.

Then, in the dynamic damper 1'according to the present embodiment, one end in the longitudinal direction (outer end in the radial direction) of each core member 6 is brought into contact with the inner peripheral surface of the weight 3 as shown in FIG. 7, and the other end in the longitudinal direction. Since the (inner end in the radial direction) is separated from the outer peripheral surface of the cylindrical portion 2 so as not to make contact with the cylindrical portion 2, there is a problem that each core material 6 is broken due to elastic deformation in the rotational direction of the connecting portion 4. In addition to preventing the occurrence, there is no problem that the radial rigidity (spring constant) of the connecting portion 4 becomes excessive and the vibration absorbing capacity is lowered.

It is sufficient that at least one end of each core material 6 in the longitudinal direction is not in contact with the cylindrical portion 2 or the weight 3, and as shown in FIG. The outer end in the direction) may be non-contact with the weight 3, or as shown in FIG. 8 (b), both ends in the longitudinal direction (inner end and outer end in the radial direction) of each core member 6 are formed. It may be non-contact with both the cylindrical portion 2 and the weight 3.

Further, in the dynamic damper 1'according to the present embodiment, since the five core members 6 which are an odd number are arranged radially at an equal angle pitch (72 ° pitch) in the circumferential direction, rotational vibration mainly in the radial direction is mainly generated. A good balance of radial rigidity (spring constant) of the absorbing connecting portion 4 can be maintained. In the dynamic damper 1'according to the present embodiment, five core members 6 are arranged at equal angles in the circumferential direction, but the number of core members 6 is not limited to five and is an odd number of three or more. If this is the case, the balance of the radial rigidity (spring constant) of the connecting portion 4 can be kept good.

In addition, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of claims and the technical ideas described in the specification and drawings.

1,1'Dynamic damper 2 Cylindrical part 3 Weight 4 Connecting part 5 Rib 6 Core material 10 Propeller shaft (rotating shaft)
11,12 Universal joint 13 Center support A Rib radial length B Rib rotation length

Claims (8)

An elastic cylinder fitted to the outer circumference of the rotating shaft,
A ring-shaped weight that is concentrically arranged radially outwardly from the cylindrical portion by a predetermined distance,
A ring-shaped connecting portion formed integrally with the cylindrical portion and connecting the cylindrical portion and the weight in the radial direction,
It is a compression / tension type dynamic damper that includes
A dynamic damper characterized in that the cylindrical portion and the weight are connected by a plurality of ribs arranged radially between the two. The dynamic damper according to claim 1, wherein three or more ribs are arranged. The dynamic damper according to claim 1 or 2, wherein the ribs are arranged in an odd number. The dynamic damper according to any one of claims 1 to 3, wherein each of the ribs is integrally formed with the cylindrical portion and the connecting portion. Each of the ribs is a rectangular parallelepiped, and the ratio A / B of the radial length A and the rotational length B is
A / B ≧ 1
The dynamic damper according to any one of claims 1 to 4, wherein the dynamic damper is set to. An elastic cylinder fitted to the outer circumference of the rotating shaft,
A ring-shaped weight that is concentrically arranged radially outwardly from the cylindrical portion by a predetermined distance,
A ring-shaped connecting portion formed integrally with the cylindrical portion and connecting the cylindrical portion and the weight in the radial direction,
It is a compression / tension type dynamic damper that includes
A dynamic damper characterized in that a plurality of radial core materials are radially embedded in the connecting portion, and at least one end of each core material in the longitudinal direction is not in contact with the cylindrical portion or the weight. The dynamic damper according to claim 6, wherein three or more core materials are arranged. The dynamic damper according to claim 6 or 7, wherein the core material is arranged in an odd number.