JPH03168443A - Vibration damper - Google Patents

Abstract

PURPOSE:To obtain a stable effect of absorbing vibration with less temperature dependency by providing a vibratory unit and a subelastic part, protruded from one side toward the other of a mass unit, in an elastic member so as to compress this subelastic part at the time of thermal expansion. CONSTITUTION:A vibration damper is constituted of a drive shaft 1 serving as a vibratory unit, cylindrical mass unit 2 arranged coaxially with a space from the drive shaft 1 and an elastic member 3 having a subelastic part 37. When an environmental temperature for use is increased, volume of the rubber- made elastic member 3 is increased by thermal expansion. Consequently, the subelastic part 37 is compressed by the drive shaft 1 and the mass unit 2 and stiffened in accordance with a thermal expansion amount. Thus by holding a spring constant of the elastic member as a whole to almost a fixed value, a stable effect of absorbing vibration with no drop of a resonance point can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a vibration damping device that absorbs harmful vibrations generated in, for example, a drive shaft device, a propeller shaft device, etc. of an automobile.

[Prior Art] Conventionally, drive shaft devices have been provided with vibration damping devices to absorb harmful vibrations caused by bending resonance, torsional resonance, etc. that occur when the drive shaft rotates. As shown in FIG. 6, such a vibration damping device includes a drive shaft 1C as a vibrating body, a cylindrical mass body 2C disposed coaxially with the drive shaft 1C at a distance, and a mass body. 2C and an elastic member 3C having a predetermined spring constant, which is disposed between the drive shaft 1C and the drive shaft 1C. In this vibration damping device, harmful vibrations generated from the drive shaft 1C are transmitted to the mass body 2C via the elastic member 3C, and the mass body 2C resonates, thereby absorbing the harmful vibrations. Note that the harmful vibration to be absorbed is determined by the spring constant of the elastic member 3C and the mass of the mass body 2C.

[Problem to be Solved by the Invention 1] However, since the elastic member 3C is made of rubber or the like, when the temperature rises, the elastic member 3C becomes soft and the preset spring constant (resonance point) decreases. The effect of absorbing harmful vibrations decreases. Therefore, when the vibration damping device is used in an environment with large temperature changes, a stable effect of absorbing harmful vibrations cannot be obtained.

The present invention has been devised in view of the above-mentioned circumstances, and its technical object is to provide a vibration damping device that can obtain a stable vibration absorption effect with little temperature dependence.

[Means for Solving the Problems] The vibration damping device of the present invention comprises: a shaft-shaped vibrating body; a cylindrical overflow body disposed coaxially with the vibrating body at a distance; and the mass body. and an elastic member having a predetermined spring constant, which is disposed between the vibrating body and the vibrating body, the elastic member protruding from one of the vibrating body and the mass body toward the other, and has a distal end thereof. A secondary elastic part is provided at a small distance from or in contact with the other vibrating body side or the mass body side, and the secondary elastic part is compressed by the vibrating body and the mass body during thermal expansion. It is characterized by the fact that

The vibrating body according to the present invention is a shaft-shaped body that generates vibrations, such as a rotating shaft that rotates in the circumferential direction, a moving body that moves in a reciprocating straight line, and a body that is temporarily attached to these to transmit vibrations. means.

The mass body is made of a rigid material such as a metal material and has a cylindrical shape, and is coaxially disposed at a distance of 4λ from the vibrating body.

The elastic member is disposed between the vibrating body and the mass body, transmits vibrations of the vibrating body to the mass body, and can be formed using a rubber material, elastic resin, or the like as a base material. The elastic member has a secondary elastic portion that characterizes the present invention. This sub-elastic part is provided from one of the vibrating body and the mass body to the other, and its tip is arranged so as to be in contact with or at a very small distance from the other vibrating body side or the mass body side. Further, the auxiliary elastic portion may be configured to protrude from both the vibrating body and the mass body toward the other, with their tips facing each other. The secondary elastic portion may be formed integrally with or independently of other portions of the elastic member. Further, the auxiliary elastic portion can be provided at any position such as the center portion or both ends of the elastic member, and not only one sub elastic portion but a plurality of sub elastic portions may be provided in the axial direction and the circumferential direction.

[Function] In the vibration damping device of the present invention, harmful vibrations are mainly absorbed in the portion of the elastic member excluding the secondary elastic portion at room temperature. Then, when the usage environment temperature becomes high, the thermally expanded sub-elastic part is compressed by the vibrating body and the mass body, so that harmful vibrations can be absorbed through the sub-elastic part. That is, the amount of compression of the auxiliary elastic portion increases in accordance with the amount of thermal expansion, and the sub-elastic portion becomes at rest with the vibrating body and the mass body, thereby making it possible to absorb harmful vibrations.

a) The secondary elastic portion becomes stiffer in accordance with the amount of compression, compensating for the softening of other parts of the elastic member due to thermal expansion, and the spring constant of the elastic member as a whole is maintained approximately constant.

[Example] Hereinafter, an example in which the vibration damping device of the present invention is applied to a drive shaft device of an automobile will be described.

(First Example) FIG. 1 shows a longitudinal sectional view of a vibration damping device according to this example. As shown in FIG. 1, this vibration damping device includes a drive shaft 1 as a vibrating body, a cylindrical mass body 2 disposed coaxially with the drive shaft 1 at a distance, and a sub-elastic part 37. The mass body 2 and the elastic member 3 are fixed to the drive shaft 1 by tightening a band.

The drive shaft 1 is made of metal and has a substantially constant diameter.

The mass body 2 has a T-shaped cross section and includes a cylindrical main body 21 and a ring-shaped protrusion 23 that protrudes inward at the center of the main body 21 . The mass body 2 is embedded in the elastic member 3, and the distal end surface 231 of the protrusion 23 is spaced apart from the outer peripheral surface of the drive shaft 1 by a predetermined distance.

The mass body 2 is integrally formed of a metal material, has a predetermined mass, and has a natural frequency matched to the frequency of harmful vibrations to be absorbed.

The elastic member 3 has a substantially arch-shaped cross section, consisting of a cylindrical central portion 31 that surrounds the mass rest 2, and ring-shaped legs 33 that are continuously provided at both ends of the central portion 31, It is integrally made of rubber material. central part 31
The inner circumferential surface side of the pawnshop body 2 is shaped to have a substantially constant thickness along the inner circumferential surface of the pawn shop body 2, and a hollow portion 35 is formed on each side of the protrusion portion 23 of the pawn shop body 2. . The inner circumferential surface of the central portion 31 of the portion that covers the tip end surface 231 of the protrusion portion 23 is in contact with the outer circumferential surface of the drive shaft 1 facing the central portion 31, and this abutting portion is mainly used as a secondary portion. It constitutes an elastic section 37. A band groove 332 is formed on the outer circumferential surface of the leg portion 33, and the elastic member 3 is fixed to the drive shaft 1 by a band 39 attached to the band groove 332.

In the vibration damping device configured as described above, harmful vibrations generated by rotation of the drive shaft 1 and the like are absorbed by resonance of the transmission shear mass body 2 mainly through the legs 33 at room temperature.

When the operating environment temperature becomes high, the elastic member 3 made of rubber increases in volume due to thermal expansion.

However, the drive shaft 1 and mass body 2 are made of metal.
Since the coefficient of thermal expansion is small, the distance between the two hardly changes. Therefore, the auxiliary elastic portion 37 is compressed and hardened by the drive shaft 1 and the mass body 2 in accordance with the amount of thermal expansion.

As a result, the reduction in the spring constant of the leg part 33, which becomes soft at high temperatures, is compensated for by the participation of the auxiliary elastic part 37, and the spring constant of the entire elastic member is maintained almost constant, resulting in stable vibration absorption without a drop in the resonance point. effect can be obtained.

Therefore, even at high temperatures, harmful vibrations of a predetermined frequency are absorbed in the same way as at normal temperatures.

As described above, the vibration damping device of this embodiment has the sub-elastic part 37
, and when the operating environment temperature becomes high, the secondary elastic part 3
7 is configured to thermally expand and be compressed by the drive shaft 1 and the protrusion 23 of the mass body 2,
It can absorb certain harmful vibrations even at high temperatures. Therefore, the vibration damping device of this embodiment has little temperature dependence, and can obtain a stable harmful vibration absorption effect even when used at a location where temperature changes are large.

In addition, in the above embodiment, the mass body 2 is composed of the main body part 21 and the protrusion part 2.
3, but as shown in FIG.
The thickness, size, hardness, etc. of a may be changed in various ways.

(Second Embodiment) Fig. 3 shows a vertical cross-sectional view of a vibration damping device according to this embodiment.As shown in Fig. 3, this vibration damping device has a An inner cylindrical metal fitting 4 as a vibrating body that is integrally attached, a cylindrical mass body 5 arranged coaxially with the inner cylindrical metal fitting 4 at a distance, and a space between the mass body 5 and the inner cylindrical metal fitting 4. The elastic member 6 is disposed in the elastic member 6 and has an auxiliary elastic portion 67.

The inner cylindrical metal fitting 4 includes a cylindrical portion 40 having a through hole 41 that is press-fitted into the outer circumferential surface of the drive shaft, and a ring portion 42 temporarily fixed to the center of the outer circumferential surface of the cylindrical portion 40. The ring portion 42 has a rectangular cross section and protrudes outward from the outer peripheral surface of the cylindrical portion 40 .

The mass body 5 includes a cylindrical central portion 51 and caulked portions 5 formed by caulking both ends of the central portion 51 inward in the radial direction.
It consists of 3. This mass body 5 is integrally formed of a metal material.

The elastic member 6 consists of a central part 61 that surrounds the surface of the ring part 42 of the inner cylinder fitting 4, and ring-shaped main elastic parts 63 arranged at intervals on both sides of the central part 61, and is made of a rubber material. The overall shape is approximately cylindrical. The main elastic part is
The inner circumferential surface thereof is vulcanized and bonded to the outer circumferential surface of the cylindrical portion 40 of the inner cylindrical metal fitting 4, and the outer circumferential surface thereof is bonded to the inner circumferential surface of the mass support 5. The inner peripheral surface of the central portion 61 is vulcanized and bonded to the ring portion 42, and is formed to have a substantially constant thickness.

The central portion 61 of the portion covering the tip end surface 421 of the ring portion 42 has an outer circumferential surface facing the mass body 5.
This abutting portion constitutes a sub-elastic portion 67 as a main body. In addition, the central part 61
A hollow portion 65 is formed between the main elastic portion 63 and each main elastic portion 63 .

The vibration damping device constructed as described above can be constructed by press-fitting the through hole 41 of the inner cylinder fitting 4 into the drive shaft.
It is attached to the outer circumferential surface of the drive shaft and is ready for use. In this state at room temperature, harmful vibrations generated due to rotation of the drive shaft, etc., are absorbed by resonance of the shear mass body 5 transmitted from the inner cylinder fitting 4 mainly through the main elastic portion 63. When the usage environment temperature becomes high, the secondary elastic part 67 thermally expands and becomes compressed and hardened by the ring part 42 of the inner cylinder fitting 4 and the mass body 5, so that harmful vibrations are generated through the secondary elastic part 67. The spring constant of the elastic member 6 as a whole is maintained substantially constant by the auxiliary elastic portion 67. Therefore, even at high temperatures, harmful vibrations of a predetermined frequency are absorbed in the same way as at normal temperatures.

As described above, the vibration damping device of this embodiment can absorb predetermined harmful vibrations even at high temperatures in the same way as at normal temperatures, and the same effects as in the first embodiment can be obtained.

In the above embodiment, the inner cylindrical metal fitting 4 was composed of the cylindrical part 40 and the ring part 42, but as shown in FIG.
b may be formed of only the portion corresponding to the cylindrical portion (the height of the ring portion may be changed), and the thickness, size, hardness, etc. of the auxiliary elastic portion 67b may be varied in various ways.

Further, the mass body 5b may have a ring-shaped or block-shaped mass member 55b temporarily provided on its outer peripheral surface.

Further, in the above embodiment, the secondary elastic part 67 was provided only on the inner cylindrical metal fitting 4 side, but an elastic body such as rubber is provided on the inner periphery of the mass body 5 so that the inner cylindrical metal fitting 4 and the mass body 5 The auxiliary elastic portions 67 may be configured to protrude from both sides and face each other so that their tip surfaces abut each other.

(Third Embodiment) FIG. 5 shows a cross-sectional view of a vibration reduction device according to this embodiment. As shown in FIG. 5, the vibration damping device of this embodiment includes an inner cylindrical metal fitting 7 attached to the outer circumferential surface of a drive shaft, and a cylindrical metal fitting 7 coaxially disposed at a distance from the inner cylindrical metal fitting 7. The elastic member 9 is disposed between the mass body 8 and the inner cylindrical fitting 7 and has an auxiliary elastic portion 97.

The inner cylinder fitting 7 is made of metal or an elastic body such as rubber.

The mass body 8 includes a cylindrical central portion 81 and a protrusion srsa5 having a rectangular cross section and extending from the inner circumferential surface of the central portion 81 and extending along the axial direction. Four protrusions 85 are provided at equal intervals, and each protrusion 85 is shaped to have the same length as the central portion 81.

The distal end surface 851 of each protruding portion 85 is separated from the outer circumferential surface of the inner cylinder fitting 7 by a predetermined distance.

The elastic member 9 includes an intermediate section 91 having four main elastic sections 93 and four sub-elastic sections 97, each of which is provided independently.
It consists of The main elastic portion 93 includes each protrusion portion 85 of the mass body 8.
The inner cylindrical metal fitting 7 extends along the axial direction at a position between
It is vulcanized and adhered to the outer peripheral surface of the mass body 8 and the inner peripheral surface of the mass body 8 and is held therein. The intermediate portion 91 has an inner circumferential surface that is in contact with the protrusion portion 85, and is formed to have a substantially constant thickness. The intermediate portion 91 of the portion covering the tip 851 of the protrusion portion 85 of the mass body 8 has a portion of its outer circumferential surface as the inner cylindrical fitting 7.
This abutting portion constitutes a sub-elastic portion 97 as a main body.

The vibration damping device constructed as described above is used by being mounted on the outer peripheral surface of the drive shaft as in the case of the second embodiment. Also in the case of this vibration damping device, when the operating environment temperature becomes high, the secondary elastic portion 97 thermally expands and is compressed by the inner cylinder fitting 7 and the protrusion portion 85 of the purchaser body 8. Because of this, predetermined harmful vibrations can be absorbed even at high temperatures in the same way as at normal temperatures, and the same effect as in the second embodiment can be obtained.

Further, in the vibration damping device of this embodiment, since the sub-elastic part 97 is provided along the axial direction, the vibration-absorbing effect of the sub-elastic part 97 can be reliably increased by 1q over a wide range in the axial direction.

[Effects of the Invention] The vibration damping device of the present invention protrudes from one of the vibrating body and the pawnshop body toward the other, and its tip is provided with a small distance between or in contact with the other vibrating body side or mass body side. It has a secondary elastic part, and is configured so that the secondary elastic part is compressed by the vibrating body and the mass body during thermal expansion,
It is possible to obtain a stable harmful vibration absorption effect with little temperature dependence.

[Brief explanation of the drawing]

1 and 2 relate to a first embodiment of the present invention, FIG. 1 is a longitudinal sectional view of a vibration damping device, and FIG. 2 is a longitudinal sectional view of a vibration damping device according to a modification. 3 and 4 relate to the second embodiment, where FIG. 3 is a longitudinal sectional view of a vibration damping device, and FIG. 4 is a longitudinal sectional view of a vibration damping device according to a modification. FIG. 5 is a cross-sectional view of a vibration damping device according to a third embodiment. FIG. 6 is a longitudinal sectional view of a conventional vibration damping device. 1... Drive shaft (vibrating body) 4, 7... Inner cylinder fitting (vibrating body) 2, 5, 8... Mass body 3, 6, 9... Elastic member 37, 67, 97...・Secondary elastic part

Claims (1)

[Claims] (1) A shaft-shaped vibrating body, a cylindrical mass body disposed coaxially with the vibrating body at a distance, and a predetermined spring constant disposed between the mass body and the vibrating body. In the vibration damping device, the elastic member projects from one of the vibrating body and the mass body toward the other, and its tip is spaced apart from the other vibrating body side or the mass body side by a minute distance, or A vibration damping device comprising a sub-elastic part provided in contact with each other, the sub-elastic part being compressed by the vibrating body and the mass body during thermal expansion.