JPH0537058Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention particularly relates to a dynamic damper for achieving a damping effect on rotational fluctuations in a vehicle drive system.

(Prior Art) As is well known, the basic structure of this type of dynamic damper is a mass member with a predetermined mass, and this mass member and a predetermined vibration damping target (hereinafter referred to as the main vibration system). It is constructed by combining an elastic body such as rubber that exhibits spring characteristics between the two.

As a dynamic damper for a vehicle drive system, one is known in which an elastic body such as rubber is fixed to the outer periphery of a rotating shaft or the like in the drive system, and a mass member is further fixed to the outer periphery of this elastic body. (For example, see Utility Model Application Publication No. 58-76843). The structure of a dynamic damper that is almost similar to this was developed in 1983.
It is also disclosed in Japanese Patent Application Laid-Open No. 58-177720.

(Problem to be solved by the invention) In general, dynamic dampers for vehicle drive systems are controlled by matching their natural frequency to the rotational fluctuation frequency of the main vibration system in the region to be damped. Designed to enhance the vibration effect. At the same time, setting the mass of the mass member in the dynamic damper as large as possible and setting a large mass ratio between the dynamic damper and the main vibration system will increase the vibration damping effect of the main vibration system. is known to be effective.

However, the mass of the vehicle drive system is very large compared to the weight of a typical main vibration system. Therefore, in order to increase the above mass ratio, it is required to increase the mass of the mass member and its shape.
As a result, the installation space for the dynamic damper and the weight of the vehicle increase, creating a problem that it is difficult to accommodate vehicles that are subject to restrictions in these respects.

The present invention aims to solve these problems.

(Means for solving the problems) In order to solve the above problems, the present invention is configured as follows.

For example, as shown in Fig. 1, the support shaft 5 of the main vibration system
A sun gear 11 of a planetary gear set 10 is fixed to. A plurality of pinions 13 positioned by a carrier 15 are installed between the sun gear 11 and a ring gear 16 which also serves as a mass member 17. Furthermore, an elastic body 18 is provided between the sun gear 11 and the carrier 15, which exhibits a spring characteristic in the torsional direction between them.

(Function) According to the above configuration, the rotational fluctuation of the vehicle drive system, which is the main vibration system, causes the planetary gear set 10 to
When the sun gear 11 causes rotational fluctuation, the ring gear 16, which also serves as the mass member 17, rotates while deforming (torsionally deforming) the elastic body 18 depending on the gear ratio. At this time, the spring characteristics of the elastic body 18 in the torsional direction exert a damping effect on the main vibration system.

In the dynamic damper using the planetary gear set 10, the moment of inertia of the dynamic damper as seen from the sun gear 11 side is amplified by the gear ratio, and the mass ratio with the main vibration system of the dynamic damper is increased. It has a similar effect. As a result, even when the mass of the mass member 17 is large, such as in a vehicle drive system, the above-mentioned mass ratio is increased without increasing the substantial mass of the mass member 17, that is, a good vibration damping effect as a dynamic damper is achieved. is obtained.

Further, by constructing a dynamic damper using such a planetary gear set 10, the centering of the mass member 17 is well maintained, its radial movement is restricted, and rotational imbalance is eliminated.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

First Embodiment First, in FIGS. 1 and 2, a tube yoke 2, which is a component of a shaft joint, is fixed to the end of a hollow propeller shaft 1 by welding or the like. Further, inside the propeller shaft 1, a support plate 3 is fixed to the end surface of the tube yoke 2 by bolts 4. One end of a support shaft 5 is attached to the support plate 3 on the rotational axis of the propeller shaft 1 by fixing means such as press fitting. In other words, the support shaft 5 forms part of the vehicle drive system (main vibration system) and rotates together with the propeller shaft 1 through the support plate 3 and the tube yoke 2.

A sun gear 11 of a planetary gear set 10 is assembled on the outer periphery of the support shaft 5 from the right side in FIG. 1 in a centered manner. A nut 7 is fastened to the end of the support shaft 5 via a retainer 6, thereby fixing the sun gear 11 so as to rotate together with the support shaft 5. Further, a cylindrical mass member 17 is fixed to the ring gear 16 of the planetary gear set 10 disposed on the outer periphery of the sun gear 11 inside the propeller shaft 1 by means such as press fitting so as to rotate together with the ring gear 16. has been done. The left end of the mass member 17 is held centered with respect to the support shaft 5 by a pusher 8.

Further, a plurality of (four in the drawings) pinions 13 are installed between the sun gear 11 and the ring gear 16. These pinions 13 are rotatably supported by respective shafts 14 fixed to a cylindrical carrier 15.

On the outer periphery of the sleeve 12, which is fixed to the outer periphery of the extension part 11a of the sun gear 11 by means such as press fitting, the inner periphery of an elastic body 18 formed in an annular shape from a material such as rubber is attached by means such as vulcanization adhesion. It is fixed. Further, the outer periphery of the elastic body 18 is fixed to the inner periphery of the carrier 15 by means such as vulcanization adhesion.

The reason why the elastic body 18 is fixed to the outer periphery of the sun gear 11 by the sleeve 12 is simply for manufacturing convenience. Of course, direct fixation is also possible.

Next, the determination of the specifications of the dynamic damper will be explained with reference to FIG. 3, which shows a schematic diagram of the dynamics of the dynamic damper. First, in FIG. 3, M indicates the mass of the main vibration system, and in the case of a vehicle drive system, it is the total mass of the transmission, propeller shaft, differential device, etc. m is the mass of the dynamic damper, and in this embodiment is the mass of the mass member 17 including the ring gear 16.
Further, K is a spring constant of the main vibration system, and in the case of a vehicle drive system, is its rigidity. k is a spring constant of the dynamic damper, and c is a damping coefficient of the dynamic damper, which is determined by the internal hysteresis of the elastic body 18 and the like. F is an excitation force, and in the case of a vehicle drive system, it is generated due to rotational fluctuations due to engine explosion, etc. Furthermore, x1,
x2 is the displacement of the main vibration system and dynamic damper.

Now, when the above M is displaced by the excitation force Fsinωt, if m is added to this M to suppress the displacement of M, the parameter that minimizes the vibration of M can be given by the following equation. Generally known.

Xst=F/K: Static deflection of the main vibration system Ωn=√: Natural frequency of the main vibration system ωn=√: Natural frequency of the dynamic damper μ=m/M: Mass of the dynamic damper and the main vibration system Ratio ζ=c/2√: Attenuation rate of dynamic damper ωn/Ωn=1/(1+μ) (optimal tuning) ……(1) ζ=√38(1+) ³ (optimal damping) ……(2) This Then, the maximum amplitude (X1/Xst)max of M is obtained by the following formula.

(X1/Xst)max=√1+(2)...(3) X1: Displacement amplitude of main vibration system According to the above equation (3), μ should be set large to keep the maximum amplitude of M small. I understand.
In fact, it is known that the damping effect as a dynamic damper is properly exhibited when (μ=m/M≧0.2).

When looking at this in terms of a dynamic damper in a vehicle drive system, the above M must be set extremely large in order to satisfy the condition (μ≧0.2) in the vehicle drive system.

Now, in this embodiment, the planetary gear set 10 is
A dynamic damper is constructed using this.
The operating principle of the planetary gear set 10 will now be explained with reference to FIG.
The rotation angle θ' of 6 is θ'=(1+ρ)θ. Then, let the number of teeth of sun gear 11 be Zs,
When the number of teeth of the ring gear 16 is Zr, the gear ratio ρ is ρ=Zs/Zr, and ρ is 0<ρ<1.

Also, when the moment of inertia of the ring gear 16 including the mass member 17 is I, this is the moment of inertia of the sun gear 1.
The moment of inertia I' when viewed from the first side is given by the following formula.

I'=(1+ρ) ²・I Here, since ρ>0, I'>I, and in the dynamic damper using the planetary gear set 10, the above gear ratio ρ can be achieved without increasing its mass. Therefore, the moment of inertia is amplified.

Now, in FIGS. 1 and 2, when the sun gear 11 of the planetary gear set 10 causes rotational fluctuations due to rotational fluctuations in the vehicle drive system, which is the main vibration system,
Due to the gear ratio ρ, the ring gear 16 including the mass member 17 deforms the elastic body 18 (torsional deformation).
Rotate while rotating. At this time, the spring characteristics of the elastic body 18 in the torsional direction exert a damping effect on the main vibration system. In a dynamic damper using this planetary gear set 10, as mentioned above, the moment of inertia of the dynamic damper viewed from the sun gear 11 side is amplified, so the mass ratio (inertia) between the dynamic damper and the main vibration system moment ratio) increases.

As a result, even when the mass of the vehicle drive system, that is, M of the main vibration system is large, the above-mentioned condition (μ≧0.2) is satisfied without increasing the substantial mass m of the mass member 17. It is possible,
A good vibration damping effect can be obtained as a dynamic damper for vehicle drive systems.

Furthermore, by configuring the dynamic damper using the planetary gear set 10 in this manner, the centering of the mass member 17 is well maintained, its radial movement is restricted, and rotational imbalance is eliminated. Therefore, problems such as noise generation in the vehicle drive system due to unbalanced rotation of the mass member 17 or increased load on the support bearing can be solved. This makes it possible to avoid situations such as securing a space in consideration of the radial movement of the mass member 17 and reinforcing various support bearings when installing the dynamic damper.

Second Embodiment In the embodiment shown in FIG. 5, a dynamic damper is assembled to a sleeve yoke 31 of a vehicle drive system.
1 is fixed to a cylindrical body 32 that is press-fitted onto the outer periphery of a sleeve yoke 31. Further, the ring gear 16 of the planetary gear set 10 has a shape that also serves as the mass member 17 of the first embodiment described above.

Note that a retainer 33 that positions the carrier 15 in the axial direction is fixed to an end surface of the ring gear 16 with bolts 34. Furthermore, an elastic body 18, which acts as a dynamic damper and exhibits spring characteristics in the torsional direction, is fixed to the outer periphery of the cylinder 32 and the inner periphery of the carrier 15, respectively, by means such as vulcanization adhesion.

Third Embodiment The embodiment shown in FIG. 6 includes the end face of the mass member 17 in the first embodiment described above and the support bush 8 that holds the mass member 17 in a centered state.
A thrust washer 40 and a cone spring (or wave spring) 41 are assembled between the mass member 17 and the ring gear 16 integrally connected thereto to apply a thrust force in the right direction in FIG. And the above thrust washer 4
0 and the end face of the mass member 17, and the support plate 3 is fixed to the support shaft 5 on the end face of the ring gear 16.
Another thrust lining 43 is fixed in frictional contact with.

According to this configuration, a frictional force is obtained by the thrust linings 42 and 43 by the rotation of the mass member 17 including the ring gear 16, and this frictional force can also be obtained by adjusting the elasticity of the spring 41. Can be adjusted.

As already explained, the damping rate of the dynamic damper is expressed as ζ＝c/2√, and this damping rate ζ is greatly affected by the damping coefficient c of the dynamic damper. The optimal damping is ζ＝√38(1+) ³ as expressed in the previously explained formula (2), and the optimal damping can be obtained by adjusting the damping coefficient c of the dynamic damper.

However, the damping coefficient c of a typical dynamic damper is almost determined by the spring constant of an elastic body such as rubber, and adjusting this depends on the formulation of the material, such as changing the amount of additives to the rubber. Therefore, the adjustment range of the damping coefficient c is minute.

On the other hand, in the case of a dynamic damper having the configuration shown in FIG. be. As a result, the damping coefficient c of the dynamic damper can be freely set, and thereby optimal damping can be obtained as a dynamic damper.

Furthermore, according to this embodiment, the damping coefficient c as a dynamic damper can be set mainly by the frictional force generated by the above-mentioned thrust liners 42 and 43, so the damping coefficient c can be set by adjusting the internal hysteresis of the elastic body 18, for example. The internal heat generation of this elastic body 18 is smaller than that in the case where the elastic body 18 is set, and the durability of this elastic body is improved. Further, in this embodiment, since the movement of the ring gear 16 and the mass member 17 in the width direction is restricted by the spring 41, vibrations in the axial direction of these members and the problems associated therewith are also eliminated.

(Effects of the invention) As described above, the present invention fixes the sun gear of a planetary gear set to the main vibration system, and incorporates a pinion positioned by a carrier between the sun gear and the ring gear that also serves as a mass member. Moreover, by providing an elastic body that exhibits torsional spring characteristics between the sun gear and the ring gear or between the sun gear and the carrier, the moment of inertia of the dynamic damper seen from the main vibration system can be adjusted to the gear ratio of the planetary gear set. As a result, the same effect as when the mass ratio between the main vibration system and the dynamic damper is set large can be obtained without increasing the mass of the mass member in the dynamic damper. This can be used as a dynamic damper to increase the damping effect of the main vibration system in cases where the weight of the main vibration system is extremely large, such as in a vehicle drive train, without increasing the mounting space for the dynamic damper or the weight of the vehicle. It is effective for

Moreover, the present invention utilizes a planetary gear set to configure the dynamic damper.
The centering of the mass members in this dynamic damper is maintained properly, and various problems such as abnormal noises in the vehicle drive system caused by unbalanced rotation of the mass members or increased loads on various support bearings can be resolved. can.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a longitudinal cross-sectional view of a propeller shaft incorporating a dynamic damper, Fig. 2 is a cross-sectional view taken along the line - - of Fig. 1, and Fig. 3 shows the dynamics of the dynamic damper. 4 is a schematic diagram of a planetary gear set, FIG. 5 is a vertical sectional view showing the dynamic damper of the second embodiment, and FIG. 6 is a vertical sectional view showing the dynamic damper of the third embodiment. It is. 5... Support shaft, 10... Planetary gear set, 11... Sun gear, 13... Pinion, 15
...Carrier, 16...Ring gear, 17...Mass member, 18...Elastic body.

Claims (1)

[Scope of utility model registration request] A sun gear of a planetary gear set fixed to the main vibration system, a ring gear that also serves as a mass member arranged via a plurality of pinions positioned with respect to the sun gear by a carrier, and a torsion direction between the sun gear and the carrier. A dynamic damper that includes an elastic body that exhibits spring characteristics.