JPH0745894B2 - Dynamic damper - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dynamic damper mounted around a rotary shaft such as a drive shaft of an automobile to suppress harmful vibrations on the rotary shaft, and is particularly mounted. The present invention relates to a dynamic damper that facilitates press fitting work.

[Prior Art] In order to suppress harmful vibrations that should not occur originally, such as bending vibrations and torsional vibrations due to rotational unbalance caused by the rotation of rotary shafts such as drive shafts and propeller shafts of automobiles, etc. Is often used.

Conventionally, the dynamic damper is as shown in FIG.
The fixing member 101 inserted and held on the rotating shaft S, and the fixing member 101.
It is composed of a cylindrical mass member 102 arranged on the outer periphery of the elastic member 103, and an elastic member 103 sandwiched between the fixing member 101 and the mass member 102 and connecting them. When this dynamic damper is mounted on the rotary shaft S, one end of the fixing member 101 of the dynamic damper is aligned with the shaft end of the rotary shaft S, and the dynamic damper is press-fitted in that state. At this time, the inner diameter of the fixing member 101 of the dynamic damper is set to be slightly smaller than the outer diameter of the rotating shaft S in order to ensure the fixing at the time of mounting.

[Problems to be Solved by the Invention] However, in the above-described conventional dynamic damper, when the rotary shaft is mounted on the rotary shaft by press fitting, the fixed member having an inner diameter slightly smaller than the outer diameter of the rotary shaft has When inserted, it is pushed outwards. At this time, a large amount of force is required, and the press-fitting work is accompanied by great difficulty.

Further, recently, attempts have been made to reduce the rigidity of a rotary shaft such as a drive shaft of an automobile or the like and set the resonance frequency thereof to a frequency range that is unlikely to occur in a vehicle speed range of normal driving. This is done by making the shaft diameter of the rotary shaft a little smaller, but in consideration of the whole of the automobile or the like, the mounting portion thereof, that is, the shaft end diameter of the rotary shaft is formed to have the same diameter as the conventional one. Therefore, a rotary shaft such as a drive shaft on which the dynamic damper is mounted has a non-uniform diameter with a small shaft diameter at the mounting portion and a thick shaft end portion. As a result, when trying to mount the conventional dynamic damper on this rotary shaft, if the inner diameter of the dynamic damper is set according to the outer diameter of the rotary shaft at the mounting site, it becomes impossible to press fit from the shaft end of the rotary shaft. Become. On the contrary, if the inner diameter of the dynamic damper is set to a diameter that can be press-fitted from the shaft end, the dynamic damper cannot be fixed at the mounting site. No conventional dynamic damper can be used for such a rotary shaft.

Therefore, an object of the present invention is to facilitate the press-fitting work of a dynamic damper when it is mounted on a rotary shaft, and for a rotary shaft in which the shaft diameter of the shaft end portion is larger than the shaft diameter of the mounting portion. It is to provide a dynamic damper that can be mounted and has excellent mounting workability.

[Means for Solving the Problems] A dynamic damper according to the present invention has a ring shape having at least one slit extending in the axial direction and having a wide interval in the circumferential direction and having an inner peripheral surface smaller than the outer peripheral surface of a mounting portion of a rotary shaft. And a pair of fixing members that are inserted through and supported by the rotary shaft at intervals in the axial direction, and an inner peripheral surface that is larger than the outer peripheral surface of the fixed shaft, and are formed into a non-separable tubular shape over the entire circumference, A mass member that is inserted through the rotary shaft and that is disposed between a pair of fixing members, and the fixing members and the end portions of the mass members are integrally connected to each other. An annular space formed by extending an inner peripheral surface larger than the peripheral surface from the inner peripheral surface of the mass member and continuously extending axially outward of the mass member between the inner peripheral surface of the mass member and the outer peripheral surface of the rotating shaft. And an elastic member that defines

[Operation] In the dynamic damper of the present invention, at least one slit is formed in the pair of fixing members that are fixed to the rotating shaft. The slit is formed by extending in the axial direction of the fixing member. The slit of the fixing member is expanded in the circumferential direction, so that the diameter of the rotary shaft through which the fixing member can be inserted is significantly increased. Further, the mass member has a cylindrical shape having an inner peripheral surface larger than the outer peripheral surface of the rotating shaft to be inserted. At this time,
When the shaft diameter of the rotating shaft is not uniform, the mass member has an inner peripheral surface larger than the outer peripheral surface having the largest outer diameter. As a result, the dynamic damper of the present invention has a fixing member having an inner peripheral surface corresponding to the shaft diameter at the mounting portion of the rotating shaft to be inserted, and an inner periphery larger than the largest shaft diameter of the entire inserting path of the rotating shaft. By having a mass member having a surface, it is possible to easily expand the slit of the fixing member not only for a rotating shaft having a uniform shaft diameter, but also for a rotating shaft having a shaft diameter of a mounting portion smaller than the other shaft diameters. It is possible to install by. Since both ends of the mass member are supported by the elastic members, the supporting direction is the shearing direction, which effectively acts to realize a low resonance frequency.

[Example] A dynamic damper of an example according to the present invention,
A description will be given with reference to FIGS. 1 to 3. FIG. 1 is a vertical sectional view taken along the line AA ′ in FIG. 2 of the dynamic damper of the embodiment, FIG. 2 is a side view thereof, and FIG. 3 is a partial vertical sectional view showing its mounting state.

The dynamic damper of the present embodiment is used for damping a drive shaft of an automobile, and is press-fitted and attached to the drive shaft, and in particular, the shaft end has a larger shaft diameter than the mounting portion. Suitable for use on drive shafts.

The dynamic damper of the present embodiment is a pair of ring-shaped members having two slits 11, 11 extending in the axial direction and expanding in the circumferential direction, and inserted and supported by a drive shaft S, which is a rotating shaft, at predetermined intervals. Fixing members 1, 1 and a mass member 2 having an inner peripheral surface larger than the largest outer peripheral surface of the drive shaft S and arranged between the pair of fixing members 1, 1, and the respective fixing members 1, 1 And elastic members 3, 3 that integrally connect the respective ends of the mass member 2 with each other.
And, as a whole, it has a substantially cylindrical shape in which the outer diameter of the central portion is larger than those of both end portions. Here, the mass member 2 corresponds to the central portion, and the fixing members 1 and 1 correspond to both end portions. The elastic members 3 and 3 correspond to a connecting portion that connects the central portion and both end portions with an inclination.

The fixing members 1 and 1 are divided into two by slits 11 and 11 and are used as a pair in the form of a ring as a whole, and are made of a rubber material such as natural rubber. The one end portion side is integrally connected to the elastic member 3, and the ring shape is held. The diameter of the inner peripheral surface forming the central shaft hole of the fixing member 1 is slightly smaller than the diameter of the outer peripheral surface of the mounting portion of the drive shaft S. Also, the fixing member 1
A ring-shaped locking groove 12 is formed on the outer peripheral surface of the.
The slits 11 and 11 are formed at positions axially symmetrical to the fixing member 1 so as to have a slit width of about 1 to 2 mm and reach the elastic member 3 integrally connected from the end face in the axial direction.

The mass member 2 is formed by coating a metal mass body such as a cylindrical thick-walled steel pipe with a rubber material such as natural rubber on both the outer peripheral surface and the inner peripheral surface with a thickness of about 1 mm. Set up. The inner peripheral surface of the mass member 2 has a diameter slightly larger than the outer peripheral surface having the largest diameter that corresponds to the insertion path of the drive shaft S to be inserted. Therefore, when the shaft diameter of the insertion path is larger than the shaft diameter of the mounting portion, the size of the shaft diameter between the inner peripheral surface of the mass member and the outer peripheral surface of the drive shaft S at the mounting portion is large. A gap slightly larger than the difference in height is formed. At this time, both ends of the mass member 2 are supported by the elastic members 3 in the shearing direction.

The elastic member 3 has a hollow truncated cone shape formed of a rubber material such as natural rubber, and integrally connects the fixing member 1 and the mass member 2. That is, the inner peripheral surface 31 of the elastic member 3 is adjusted from the outer peripheral surface of the drive shaft S to the drive shaft of the mounting target while gradually increasing the inner diameter from the inner peripheral surface end of the fixed member 1 that is in close contact with the drive shaft S. The mass member 2 is tapered to the end of the inner peripheral surface having the set gap. The outer peripheral surface 32 of the elastic member 3 is fixed to the fixing member 1.
The outer diameter of the engaging groove 12 is gradually increased from the end portion of the engaging groove 12 formed on the outer peripheral end portion of the mass member 2. At this time, the fixing member 1 is divided into two by the slit 11, but since one end of the fixing member 1 is connected to the elastic member 3, the fixing member 1 is integrally held in a ring shape. The elastic member 3 also bears the restoring force of the fixing member 1 when the slit 11 is expanded in the circumferential direction.

The rubber coatings of the fixing members 1, 1, the elastic members 3, 3 and the mass member 2 are integrally vulcanized and molded.

Next, the use of the dynamic damper of this embodiment constructed as described above will be described.

First, when the dynamic damper is attached to the drive shaft S, the insertion opening in the fixing member 1 of the dynamic damper is aligned with the shaft end of the drive shaft S before the drive shaft S is assembled to the automobile body. Fixed member 1
Although the inner peripheral surface of the fixing member 1 has a smaller diameter than the outer diameter of the drive shaft S, the fixing member 1 can be easily expanded by expanding the two slits 11 formed in the fixing member 1 in the circumferential direction.
The diameter of the inner peripheral surface of is large. The drive shaft S easily inserts through the inner peripheral surface of the enlarged fixing member 1.
After arranging the dynamic damper at a predetermined position, the slits 11, 11 of the fixing member 1 are returned to the original state, and the locking grooves 12, 12 formed on the outer circumferences of the both fixing members 1, 1 are fixed to the fixing band 13. , Fix with 13. In this way, the dynamic damper is mounted on the drive shaft S. Similarly, the dynamic damper can be easily removed.

When the drive shaft S rotates and harmful vibration is excited therein, the mass member 2 of the dynamic damper in which the natural frequency is adapted to the frequency of the harmful vibration resonates. This natural frequency is basically set by the mass of the mass member 2 and the spring constant of the elastic member 3 in the shearing direction. At this time, the spring constant of the elastic member 3 is generally smaller in the shearing direction than in the compression / tensioning direction, which is advantageous when the natural frequency is set low.

The dynamic damper thus formed can resonate the mass member 2 to absorb the vibration energy of the drive shaft S and suppress the harmful vibration excited in the drive shaft S.

The slit formed on the fixing member is 2 in this embodiment.
Although the number is one, it is not particularly limited as long as it is one or more.
Further, it is possible to form a plurality of protrusions on the inner peripheral surface of the mass member, the protrusions having a function of cushioning an impact when the amplitude is excessive. Although the fixing band is used as the fixing means of the fixing member in the present embodiment, it is obvious that other methods such as an adhesive method are also possible.

[Effects of the Invention] As is clear from the above description, the dynamic damper of the present invention has the slit extending in the circumferential direction formed in the fixed member, so that when the rotary shaft is inserted, the inner diameter of the fixed member is reduced. Can be large. As a result, the dynamic damper of the present invention greatly facilitates the press-fitting work when mounted on the rotary shaft. Furthermore, it was possible to easily press-fit into a rotary shaft having a shaft end having a shaft diameter larger than that of a mounting site, which was impossible in the past.

As described above, the dynamic damper of the present invention greatly facilitates press-fitting and mounting on a rotary shaft, including a rotary shaft having a non-uniform shaft diameter, and thus can greatly contribute to improvement in workability and economy.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a dynamic damper of an embodiment according to the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a partial vertical sectional view showing its mounting state. FIG. 4 is a vertical sectional view of a conventional dynamic damper. 1 ... Fixing member, 2 ... Mass member 3 ... Elastic member, 11 ... Slit

Claims (1)

[Claims] 1. A ring-shaped ring having at least one slit extending in the axial direction and expanding in the circumferential direction and having an inner peripheral surface smaller than the outer peripheral surface of the mounting portion of the rotary shaft, and rotating at predetermined intervals in the axial direction. A pair of fixing members that are inserted through and supported by the shaft, and an inner peripheral surface that is larger than the outer peripheral surface of the rotating shaft, and are formed into a non-separable tubular shape over the entire circumference. The mass member disposed between the fixing members, and integrally connecting each of the fixing members and each shaft end of the mass member adjacent to the fixing member, and the inner peripheral surface of the fixing member. A larger inner peripheral surface is formed extending from the inner peripheral surface of the mass member, and an annular space extending continuously outward in the axial direction of the mass member is defined between the outer peripheral surface of the rotating shaft and the inner peripheral surface. A dynamic damper, comprising: