BG110909A - A device for damping frictional self-excitated oscillations originating in frictional clutches - Google Patents

Abstract

Currently damping of frictional oscillations originating in transport vehicles is made by increasing damping coefficient and/or by employing frictional materials of lower slope of the frictional force curve. Employing the device by increasing mass moment of inertia in the process of engaging the clutch, damping and eliminating of self-excited frictional oscillations will be reached in transmissions of transport vehicles. The device comprises a flywheel (1) housing a clutch disc (2), a driving disc (3), cermet frictional parts, a pressure plate (5), a spring (6) and an axial bearing (7). The driving disc (3) is made of two parts that move axially one to the other both mounted in grooves of the primary shaft of a gearbox(8). Cermet frictional parts (4) are fixed to the driving disc (3). Theclutch disc (2) is situated between the two parts of the driving disc (3) mounted on bearings on the inner diameter of the flywheel. The device has the following advantages: lowering of dynamic loads in transmissions of vehicles, generated by dry friction forces

Description

TECHNICAL FIELD

The invention relates to a device for reducing friction self-excited oscillations in machine units with friction clutches. The device has a specific application in car transmissions with friction clutches, especially those with ceramic friction elements.

BACKGROUND OF THE INVENTION

With friction clutches, torque transmission begins in the process of switching on and there is a slippage (relative speed) between the friction surfaces. In this case, self-excited friction oscillations may occur due to the variable friction coefficient characteristic between the friction pairs.

The following devices are known for methods of eliminating friction self-excited oscillations in machines:

• increasing the resistance (damping) in the elements of the mechanical system;

• creating friction pairs with a smaller slope of the friction coefficient characteristic, depending on the relative sliding speed;

• friction disc adjustment and control systems.

US2004224821 (A1) proposes a system in which vehicle brakes are mounted in the transmission of a vehicle, which are engaged only at the moment of departure, the information of which is provided by sliding sensors, thereby increasing the resistance.

DE102008002343 (A1) discloses an invention relating to a circular friction element intended for friction clutches and brakes. The friction elements are shaped so that in some areas there are friction elements of one kind, in other zones of another kind. This is done in order to reduce the slope of the friction force characteristic, depending on the relative sliding speed.

EP1878936 (A2) proposes a two-composite friction material, whose friction characteristic is smoother, reducing friction vibrations.

VS2006124419 (Al) is provided with a friction disk having two friction materials.

DE 102004030479 (A1) relates to a clutch lever control system. The control is carried out with sensors signaling that there is a slip in the connector elements. This unit has a master and auxiliary power management system.

DEI02006014072 (A1) and JP2009216203 (A) relates to a method and system for the automatic control of clutch and gearbox when starting a vehicle. The system has a system for reducing friction self-excited oscillations. A block diagram for the implementation of the system is presented.

W02010028990 (A2) relates to a method and system for recognizing

slipping.

EP1539526 (B1) provides a system for reducing clutch-induced oscillations, regulated by a number of sensors sensing vibrations mounted on vehicle elements.

SUMMARY OF THE INVENTION

The invention consists in a device for reducing the vibrations caused by the friction forces in friction couplings.

The essence of the exemplary device is characterized by the addition of an additional disk to the driven friction disk of the clutch, at the moment of clutch engagement (at startup), which leads to the reduction or elimination of friction self-excited vibrations at this stage of movement.

In FIG. 1 is an exemplary embodiment of the device. Its elements are as follows:

1. Flywheel;

2. Movable disc;

3. Driven disk;

4. Ceramic friction elements;

5. Pressure disc;

6. Diaphragm spring;

7. Axial bearing;

8. Gearbox primary shaft.

All elements are housed in the flywheel housing 1, as in FIG. 1a, the connector is switched off and in FIG. 16 is in the process of being switched on. The drive disc 3 is composed of two parts that move relative to each other in an axial direction, and they are secured by slotted connections to the primary shaft of the gearbox. Fixed to the drive disc 3 are metal-ceramic friction members 4. Between

The drive disk 2 is located on the parts of the drive disk.

When the clutch is disconnected, the elements of the drive disc 3 have no contact with the removable disk. The friction elements 9 (Fig. 2), pressed by springs 10, ensure the rotation of the disk 2 together with the flywheel 1 (ωι = ω ₂ ; (»h = 0).

When the clutch is in the process of switching on (Fig. 16), the two parts of the driven disk 3 will press against the movable disk 2 and when the friction forces between them become greater than those between the flywheel 1 and the movable disk 2, moves with the drive disc 3 without sliding towards it (gas = ω ₂ , ω # ω ₂ ). Thus, in the process of switching on the clutch, the actuator and the movable disc become one body with a larger mass moment of inertia (it should be noted that there must be suitable friction elements between the movable disc and the actuating disc). Upon completion of the switching process, all bodies rotate at the same angular velocity (ω = ωι = ω ₂ = cos).

The advantages of the offered device are:

1. In the process of starting a vehicle, the mass moment of inertia of the drive disk of the clutch is increased, as a result of which the friction vibrations occurring at start-up will be reduced or completely eliminated.

2. The proposed decision does not lead to a significant structural change in

existing types of friction connectors.

3. In constructive terms, the proposed solution is technological and easy to make.

4. The ride comfort of the vehicle is increased.

EXPLANATION OF THE FIGURES Attached

In FIG. 1a shows the construction of the proposed device in the off position, and in FIG. 16 in process of inclusion.

In FIG. 2 shows an exemplary view of the proposed flywheel / drive disc coupling solution.

Claims (2)

Patent Claims 1. Device for reducing friction self-excited oscillations in friction clutch systems, including actuator disk 1, movable disk 2, actuated friction disk 3, ceramic friction elements 4, pressure disk 5, diaphragm spring 6, axial bearing 7, axial bearing 7 , friction elements 9 and springs 10, characterized in that when the clutch is disconnected, the movable disk is connected to the actuator and, in the process of switching on, it is connected to the actuated friction disk. DEVICE FOR REDUCTION OF FRICTION SELF-EXCITING THINGS THAT ARE occurring in systems with friction couplings ABSTRACT Currently, the reduction of friction vibrations occurring in vehicles is accomplished by increasing the value of the damping coefficient and / or using friction materials with a smaller slope of the friction force characteristic. Through the proposed device, by increasing the mass moment of inertia of the driven friction disk in the process of clutch engagement, it will be possible to reduce or eliminate the self-excited friction vibrations in the transmissions of vehicles. The proposed solution has the following advantages: 1) the dynamic loads in the vehicle transmissions generated by dry friction forces are reduced; 2) the ride comfort of the vehicle is increased.