FR2650357A1 - Coupling device and clutch intended to equip vehicles and machines with engines - Google Patents

Abstract

The invention relates to a coupling device and to a clutch intended to facilitate driving, particularly by mastering slip, matching the torque transmitted to starting, and by eliminating jolts during changes of gear. This device makes it possible to relieve or eliminate the slip of the frictional pieces. Maintenance is simplified. The device includes a differential 1 interposed between the drive shaft 2 and the driven shaft 3. The shaft 4 output from the differential is secured to the brake 5 and to the retarder 6. The retarder makes it possible to adjust and control the torque transmitted during the starting period. The brake, by blocking the ring gear (crown wheel) 7 makes it possible to obtain coupling of the shafts 2 and 3 without slipping. The device can operate in manual control or automatic control depending on the control and regulating members which are associated with it.

Description

 The present invention relates to a coupling and clutch device intended for equipping vehicles or motor vehicles. It includes a differential mechanism associated with a retarder and brake system allowing the transmission of engine torque under different conditions of use.

This device is intended to facilitate driving when starting and changing gears, in particular by controlling the starting torque and eliminating jolts when changing gears. It relieves or eliminates the slippage of friction parts in the power transmission. Maintenance and disassembly of friction parts are simplified.

 In the current state of the art, the most commonly used engine torque transmission system consists in interposing between the engine and the gearbox a disc clutch, the operation of which is carried out by the driver of the vehicle or machine. Another common system consists in using a hydraulic torque converter associated with a planetary gearbox, making it possible to ensure the complete automation of the transmission.

 Other systems intended to facilitate the transmission of torque and the shifting of gears involve pneumatic or electric oprmnandes, one of the last embodiments being a system comprising a disc clutch with assisted control and controlled by microcomputer.

 Hydraulic converters and couplers provide great driving comfort but they absorb a significant part of the available power; they lead to a reduction in performance except by adding blocking systems which increase the complexity and the cost of these types of transmissions.

 Friction clutches require sustained attention in order to adjust the force when the plates come into contact in order to avoid jolts. Friction causes overheating and wear of parts in ill contact, resulting in maintenance costs which are all the more significant if the clutch is used more frequently (city traffic) or durenuent solicited (traction of heavy loads).

 Power-assisted friction clutches save the driver's fatigue but, as on the classic clutch, cause friction and wear on friction parts.

 The device according to the invention makes it possible to reduce the wear and the maintenance costs of the coupling parts and it also makes it possible to obtain, at start-up, the flexibility of a hydraulic coupler while preserving the performance at higher speeds.

 According to the principle model presented in Figure 1, the device comprises a differential mechanism (1) interposed between the drive shaft (2) and the driven shaft (3); the shaft (4) at the differential outlet is integral with an assembly ensuring the brake (5) and retarder (6) functions.

The retarder makes it possible to adjust and control the torque transmitted to the shaft (3) it can act by mechanical, hydro-dynamic or electromagnetic action depending on the choice of construction.

 The brake allows the locking of the crown (7) and consequently the coupling without sliding of the shafts (2) and (3). The differential, the brake, the retarder and the corresponding direct or assisted commands constitute a transmission member of the engine torque allowing the adaptation of the torque during starting and gear changes.

 When stopped, first gear engaged, the shaft (3) does not rotate and the brake (5) is free; it follows that the speed of rotation of the solid state discs of the crown is proportional to the speed of rotation of the motor, the proportionality ratio being a construction element chosen to optimize the dimensions of the retarder.

 To start, the retarder (6) comes into action; the torque transmitted to the shaft (3) is adjusted by the torque of the retarder. The action of the retarder ceases when the brake immobilizes the crown (7); a servo-control between the speed of the motor driving the shaft (2) and the speed of the shaft (3) makes it possible to lock the brake (5) during the passage of the shaft (4) at reduced or substantially zero speed.

The device shown in Figure 1 allows
- obtain starting by introducing a torque transmission device, the adjustment and progression of which are fixed, within the limit of the available torque, independently of the engine torque. The torque transmitted can be checked by direct or assisted control.

 - obtain, during gear changes, the coupling of the motor shaft and the shaft driven by braking of the shaft (4) when the latter rotates. at reduced speed or substantially zero. This result implies a control of the motor speed to the speed of the shaft (3) for the duration of the gear change.

 - avoid sliding between the shafts (2) and (3) outside start-up periods and gear changes.

 - use fixed wearing parts accessible outside the usual housings of the transmission mechanisms.

 - have a modular system depending on the type of driving required normal, assisted or fully automatic driving.

This device also makes it possible to:
- do not stall the engine at start-up by incorrect operation of the clutch control, due to the slip authorized by the retarder.

 - keep the first gear engaged and engaged during frequent starts.

 - start the engine by driving the engine by blocking the shaft (4).

 - temporarily add flexibility at low speed, without changing speed by uncoupling the brake (5) and coupling the retarder (6).

 - maintain the driver's decision-making autonomy for changing gears or provide automatic shifts according to the auxiliary equipment attached.

 A first simplified version of the device is presented in Figure 2.

In this case, it is the brake itself which on the one hand performs the retarder function on the one hand and the brake function on the other hand during periods of unloading.

The device for transmitting the torque between the engine (10) and the parallel gearbox (11) consists of the differential (1) fitted on the output shaft (4) with a disc brake (5) with brake block (8).

In neutral the brake disc is free, the friction linings being separated from the disc.

 When a gear is engaged, the progressive braking of the disc slows down the crown (7) and causes the rotation of the primary shaft (3) of the gearbox. When the brake disc is immobilized, the shaft (3) is driven without slipping.

With respect to a conventional disc clutch mounted between the shafts (2) and (3), the device in FIG. 2 has the advantage of using fixed wear parts accessible from outside the casings of transmission: this results in ease of disassembly and maintenance.

 In the example shown in Figure 3, the torque transmission device between the engine (10) and the gearbox with parallel trains (11) consists of the differential (1) fitted on the output shaft (4) d 'a disc brake (5) with brake block (8) and an electromagnetic retarder (6) fitted with electromagnets (9); a disc clutch (12) placed on the driven shaft (3) between the differential (1) and the gearbox is intended to relieve the synchronizers of the gearbox. Its operation precedes that of the brake (5).

The principle operation therefore returns to that of FIG. 1.

This device mounted on a heavy vehicle or on a vehicle towing a load or caravan relieves clutch slippage
- during start-up, the clutch slip is eliminated; it is the sliding of the retarder which allows the progressive drive of the vehicle.

 - When changing gears, coupling occurs smoothly, the brake is locked when it changes to zero speed.

 I1 results in an economy of the clutch; a progressive action of the starting torque and a great ease of shifting gears.

 The example shown in Figure 4 is similar to the example given in Figure 3, the retarder being constituted in this case by the rotor (6) of a hydro-dynamic retarder (13): this device is more particularly suitable for heavy vehicles.

 In the example shown in Figure 5, the torque transmission device between the engine (10) and the planetary gearbox (14) is constituted by the differential (1) fitted on the output shaft (4) d 'A single disc (15) opposite which are mounted the brake block (8) and the electromagnets (9). This single disc provides the combined retarder and brake effect.

The principle operation is that of FIG. 1.

This assembly is more compact than that presented in FIG. 3; it ensures a progressive action of the starting torque and the absence of jolts when shifting gears. Its reduced size allows it to be mounted on a light vehicle.

 This system is suitable for traffic in urban areas, causing frequent stops and starts.

 The devices shown in Figures 2, 3, 4 and 5 can be equipped for conventional driving, providing the driver with driving comfort, preservation of performance, control of the choice of gear ratios.

They are also suitable for mounting ancillary equipment including speed sensors, position sensors, servos and calculator allowing full automatic gear change.

Claims (6)

 1) Coupling and clutch device for the power transmission of vehicles or motor vehicles characterized in that it comprises a differential mechanism (1) interposed between the motor shaft (2) and the driven shaft (3), l 'shaft (4) at the output of the differential being integral with a brake (5). Torque transmission is obtained by the action and adaptation of the clamping force of the brake linings.  2) Device according to claim 1 characterized in that the shaft (4) is integral with a brake (5) to which is added a retarder (6), the transmission of torque at start-up and at certain speeds being determined by the action and adjustment of the retarder (6), the brake (5) then having the function at other speeds of suppressing the sliding of the retarder by blocking the crown (7).  3) Device according to claims 1 and 2 characterized in that the brake (5) is constituted by a disc integral with the shaft (4) and equipped with a braking block (8). The braking torque is obtained by the tightening force of the friction linings of the brake block.  4) Device according to claims 2 and 3 characterized in that the retarder (6) is constituted by a hydro-dynamic retarder, the torque being obtained by the action, the adaptation and the regulation of the flow of the liquid in the wheels with blades of the pump, turbine and cooling system assembly.  5) Device according to claims 2 and 3 characterized in that the retarder (6) consists of a metal disc integral with the shaft (4) -forming the rotor of an electromagnetic retarder, the torque being obtained by the action , adaptation and adjustment of the magnetic field generated by electromagnets (9).  6) Device according to claims 2, 3 and 5 characterized in that the brake and retarder -functions are provided by a single metal disc equipped with a brake block (8) and coils of electromagnets (9).