Drive device

Details Drive device Drive device

1992-12-09

1993-10-26

Bui, Thuy M.

Endless belt power transmission systems or components

Pulley with belt-receiving groove formed by drive faces on...

Fluid pressure actuator for adjustment of member

474 18, F16H 5900

Patent

active

052561097

DESCRIPTION:

BRIEF SUMMARY
The invention concerns a drive device for transmitting torque between a drive shaft having a first belt pulley and a driven shaft having a second belt pulley. The first belt pulley has an axially fixed flange non-rotably connected with the drive shaft and a flange axially movable under the action of a pre-load apparatus. The second belt pulley is composed of an axially fixed flange non-rotably connected with the drive shaft and an axially movable flange, the axially movable flange forming, with a flange of the driven shaft, a chamber for carrying a hydraulic medium.
A drive device constructed as described above is especially used in the driving of auxiliary aggregates in motor vehicles. Such a device can here be, for instance, a generator, an air-conditioning compressor, or an air-charge compressor. In the driving of auxiliary aggregates the problem of reaching a sufficiently high speed generally arises, even at low engine speeds; on the other hand, said speeds should not be too high in the upper range of the engine speeds. This requirement can be met by using a drive device having a non-linear characteristic line. By a characteristic line it is here to be understood the ratio of the speeds of the drive and of the driven shaft of the drive device. The use of centrifugal force to change the characteristic line for the controlled drive of an auxiliary aggregate has been disclosed (DE 32 42 448 A1). Even though an adaptation, in the sense explained, can be obtained with such regulating forces, the reproducibility of the speed ratios of the driven to the driven shaft of the drive device is subject to great divergences. Said circumstance also exists mainly with the use of a plate or coil spring. Small fluctuations of the controlling and restoring forces resulting from differing friction and leverage ratios can already produce great deviations from the desired speeds of the driven shaft.
To adjust hydraulically the position of the flange of the belt pulleys has also been disclosed (DE 21 18 083 A1, DE 25 60 653 C2). In order that the pressures acting upon the belt pulleys not be tampered with by centrifugal force depending on the speed, special precautions have been taken to compensate the effect of the centrifugal force upon the hydraulic medium.
In the construction according to DE 38 30 165 Al, the position of the fixed and axially movable belt pulleys, with respect to each other, has been determined, on one hand, by a pre-load apparatus and, on the other, by an apparatus acting in accordance with centrifugal force. The apparatus that acts in accordance with centrifugal force consists of small elements such as powdered steel, copper, etc. Said apparatus takes care that the force of the pre-load apparatus be reduced as the speeds increase. In other words, the distance from each other assumed by both belt pulleys is accordingly enlarged again as the speeds increase, that is, the belt pulley is opened. The consequence of this is a reduction of the speed of the driven shaft.
Based on the arrangement of DE 25 60 653 C2, the problem to be solved by this invention is to improve a drive device, especially for the driving of auxiliary aggregates of a motor vehicle, in the sense that the speed ratios to be adjusted be reproducible with sufficient exactness. The drive device according to the invention must be specially distinguished by a small hysteresis. Adding to the stated problem, the speeds of the drive device must be precisely controllable within wide limits.
The invention solves the stated problem by the fact that the chamber is connected to a reservoir of the hydraulic medium and the centrifugal action of the hydraulic medium contained in the chamber is used for increasing the speed of the driven shaft. While in the devices of the prior art, the effect of the centrifugal action upon the adjustment of the belt pulleys was regarded as an interference, the solution according to the invention makes use of the knowledge that the rotating portion of the hydraulic medium contained in the chamber builds up a pressure whi

REFERENCES:
patent: 4717368 (1988-01-01), Yamaeuchi et al.
patent: 4735597 (1988-04-01), Cadee
patent: 4846765 (1989-07-01), Sakai

Affiliated with

Also associated with

Rating

Drive device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Drive device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drive device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-955275