JPH0636934U - Power transmission device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a power transmission device capable of suppressing the generation of abnormal noise by damping the vibration corresponding to the torsional resonance frequency of the drive system. [Structure] In a power transmission device in which a drive shaft 4 of a transmission is connected to a propeller shaft via a universal joint and the propeller shaft is differentially connected to transmit power to a rear axle, the drive shaft 4 and the drive shaft 4 are connected to each other. An inner ring 13 that rotates integrally is provided.
The outer ring 20 is rotatably fitted to the bearing via the bearing 18. Then, a plurality of recessed portions 24 facing the outer peripheral surface of the inner ring 13 are provided on the inner peripheral surface of the outer ring 20, and are fitted into the recessed portions 24 of the outer ring 20 on the outer peripheral surface of the inner ring 13, and at the torsional resonance frequency of the drive system. It is characterized in that the torsional damper 12 provided with the tuned damper rubber 25 is attached.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a power transmission device for vehicles such as large buses and trucks.

[0002]

[Prior art]

 Power transmission devices for vehicles such as large buses and trucks are generally configured as shown in FIG. That is, 1 is an engine, and the output side of this engine 1 is linked to a transmission 3 via a clutch 2. The drive shaft 4 of the transmission 3 is connected to one end of a propeller shaft 6 via a universal joint 5, and the other end of the propeller shaft 6 is connected to a differential 8 via a universal joint 7. The differential 8 transmits power to the rear wheels 10 via the rear axle 9.

By the way, this type of transmission for a large-sized vehicle generates an abnormal noise (jarring noise) at idle or at low vehicle speed. The cause of this abnormal noise is that the torsional resonance of the drive system causes a rattling noise among the many gears that make up the transmission, but this noise leaks into the vehicle and gives occupants an unpleasant feeling.

As a countermeasure against this abnormal noise, a method of changing the clutch characteristics has been attempted, but it has not been sufficient. Also, in recent heavy-duty buses, the center brake drum is removed and the noise is even louder.

[0005]

[Problems to be solved by the device]

 Therefore, there is also developed a transmission shaft equipped with a torsional damper to damp vibrations corresponding to the torsional resonance frequency of the drive system.However, since the tuning frequency is very low, the spring constant is very high. It needs to be lowered. However, if the spring constant is lowered, it is difficult to center the mass portion by the damper rubber, and there is a problem that the mass portion tends to be eccentric.

The present invention has been made in view of the above circumstances, and its purpose is to damp vibrations corresponding to the torsional resonance frequency of the drive system, reduce abnormal noise of the transmission, and perform centering. It is to provide a power transmission device equipped with a torsion damper that can be easily performed.

[0007]

[Means and Actions for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has an inner ring that rotates integrally with the drive shaft of a transmission and a rotatably fitted inner ring on the inner ring through a bearing. And a damper rubber tuned to the torsional resonance frequency of the drive system while being fitted into the concave portion of the outer ring protruding from the outer peripheral surface of the inner ring. There is a damper.

Since the outer ring that serves as the mass portion is rotatably supported by the bearing provided on the inner ring, there is no eccentricity, centering can be easily performed, and the torsional damper corresponds to the torsional resonance frequency of the drive system. It is possible to damp the generated vibration and suppress the generation of abnormal noise from the transmission.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. However, the same components as those of the related art will be denoted by the same reference numerals and description thereof will be omitted.

As shown in FIGS. 1 to 3, the drive shaft 4 of the transmission 3 is integrally provided with a flange 11 having a plurality of mounting holes 11 a, and a torsional damper 12 is fixed to the flange 11.

The torsional damper 12 will be described. Reference numeral 13 denotes an annular inner ring, and an inner peripheral portion of the inner ring 13 is provided with a mounting portion 14 that is joined to the flange 11. The mounting portion 14 has a flange. A plurality of mounting holes 14a are provided so as to correspond to the mounting holes 11a of 11. Then, the inner ring 13 is fixed to the flange 11 by joining the inner ring 13 to the flange 11 and inserting the bolts 15 into the mounting holes 11a and 14a and tightening them with the nuts 16.

A large diameter portion 17a and a small diameter portion 17b are provided on the outer peripheral portion of the inner ring 13, and a large number of bearings 18 are provided on the outer peripheral surface of the small diameter portion 17b. The bearings 18 are fitted to the small diameter portion 17b. It is held by a ring-shaped bearing pressing member 19.

An annular outer ring 20 as a mass portion is fitted to the outer peripheral portion of the inner ring 13. A large-diameter portion 21a and a small-diameter portion 21b are provided on the inner peripheral portion of the outer ring 20, and the inner peripheral surface of the small-diameter portion 21b is rollingly contacted with the bearing 18 to allow the outer ring 20 to rotate relative to the inner ring 13. It is supported. Further, a shim 22 is interposed between one side surface of the small diameter portion 21b of the outer ring 20 and the side surface of the inner ring 13 and between the other side surface of the small diameter portion 21b and the side surface of the bearing pressing member 19.

A gap 23 is provided between the inner peripheral surface of the large-diameter portion 21 of the outer ring 20 and the outer peripheral surface of the large-diameter portion 17 a of the inner ring 13, and the inner periphery of the outer ring 20 facing the gap 23. The portion is provided with a plurality of recessed portions 24 at equal intervals in the circumferential direction.

A damper rubber 25 tuned to the torsional resonance frequency of the drive system is fixed to the outer peripheral portion of the inner ring 13 facing the concave portion 24, and the damper rubber 25 protrudes into the concave portion 24 and reaches the bottom of the concave portion 24. It is fixed. The damper rubber 25 has a thinned portion 25a formed at the center thereof and circular arc portions 25b formed at both ends thereof, so that the inner ring 13 and the outer ring 20 are relatively rotated by the elastic deformation of the damper rubber 25. It has become so.

According to the power transmission device configured as described above, since the outer ring 20 serving as a mass portion is rotatably supported by the bearing 18 provided on the inner ring 13, the tuning frequency is small, and thus the damper rubber 25 is provided. Even if the spring constant of is lowered, there is no eccentricity, and centering can be performed easily.

Further, the torsional damper 12 attenuates the vibration corresponding to the torsional resonance frequency of the drive system and suppresses the generation of abnormal noise from the transmission 3. When the present inventor conducted an experiment comparing the noise level between the conventional device and this device, the results shown in Fig. 4 were obtained. The figures are noise comparisons close to the transmission. The conventional model with a center brake drum has a vehicle speed of 184 dB at 20 km / h as shown by the curve a, and the model without the center brake drum has a vehicle speed of around 20 km / h as shown by the curve b. This is 186 dB, but as shown in the curve c, this is 95 dB when the vehicle speed is low from less than 20 km / h to 30 km / h, and the torsional damper 12 absorbs torsional vibrations to cause a difference. It is obvious that the generation of sound was suppressed.

[0018]

[Effect of device]

 As described above, according to this invention, since the transmission drive shaft is provided with the torsional damper made of the damper rubber tuned to the torsional resonance frequency of the drive system, the vibration corresponding to the torsional resonance frequency of the drive system is attenuated. It can suppress the generation of abnormal noise. Further, since the outer ring that serves as the mass portion is rotatably supported by the bearing provided on the inner ring, there is an effect that centering can be easily performed without eccentricity.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a torsional damper according to an embodiment of the present invention.

FIG. 2 is a side view of the entire power transmission device of the embodiment.

FIG. 3 is a sectional view and a front view showing an enlarged main part of the embodiment.

FIG. 4 is a noise comparison diagram of a portion near a transmission.

FIG. 5 is an overall plan view of a general power transmission device.

[Explanation of symbols]

3 ... Transmission, 4 ... Drive shaft, 12 ... Torsional damper, 13 ... Inner ring, 18 ... Bearing, 20 ... Outer ring, 24 ... Recessed part, 25 ... Damper rubber.

Claims (1)

[Scope of utility model registration request] 1. A power transmission device for connecting a drive shaft of a transmission to a propeller shaft via a universal joint, and connecting the propeller shaft to a differential to transmit power to a rear axle, wherein the drive shaft is connected to the drive shaft. An inner ring that rotates integrally, an outer ring that is rotatably fitted to the inner ring via bearings and has a plurality of recesses that face the outer peripheral surface of the inner ring, and a projecting outer peripheral surface of the inner ring. A power transmission device comprising: a torsional damper which is fitted into the recessed portion of the outer ring and includes a damper rubber tuned to the torsional resonance frequency of the drive system.