JPH0258492B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a primary (drive) pulley that is coupled to an annular channel that closes radially from the outside and a fluid that is present in the channel so as to produce a fluid pressure signal that is dependent on the rotational speed of the primary pulley. a continuously variable V-belt transmission having a stationary pilot tube terminating in the channel to detect the pressure of the
The present invention relates to a transmission device for a motor vehicle, comprising an input shaft connectable to a primary pulley via a drive-away clutch.

In the transmission known from GB 2058251, the drive-away clutch consists of a fluid coupling. If the transmission is equipped with a wet plate clutch to act as a drive-away clutch, the operation of the clutch is limited to the extent that it is essential for the wet plate clutch to engage smoothly under all conditions. Can cause problems.

SUMMARY OF THE INVENTION The object of the invention is to provide a transmission device which is characterized in that it has a wet plate clutch as a drive-away clutch, which enables effective operation of the clutch.

For this purpose, a wet plate clutch acting as a drive-away clutch is actuated by fluid pressure, and the input shaft of the transmission is connected to a second annular channel that closes radially from the outside and is connected to a second stationary pilot tube. terminates in the second channel so as to sense the pressure of the fluid present in the second channel to produce a second fluid pressure signal depending on the rotational speed of the input shaft. A valve is provided for sequentially transmitting the higher of the two fluid pressure signals, and a control device is provided for regulating the fluid pressure used to operate the wet plate clutch in dependence on the transmitted fluid pressure signal. .

The use of a pilot tube known per se is
It is possible in a simple manner to obtain a hydraulic signal that is dependent on the angular velocity of the primary pulley (first fluid pressure signal) and the input shaft (second fluid pressure signal). The second fluid pressure signal is a measure of the speed of the engine coupled to the input shaft and can be used as a control signal during normal drive away from a standstill. During a drive-away, first the engine speed is increased by depressing the accelerator pedal. The increased engine speed causes an increase in the second fluid pressure signal, which causes engagement of the drive-away clutch via the control device. In a drive-away, when the vehicle begins to move from a standstill, the primary pulley initially rotates slowly and rotates slower than the input shaft unless the drive-away clutch is fully engaged. As a result, the first fluid pressure signal is low, in each case lower than the second fluid pressure signal, so that the valve transmits only the second fluid pressure signal to operate the drive-away clutch. do.

When driving downhill, problems can suddenly appear if the second fluid pressure signal is always used to operate the drive-away clutch. During operation, when the speed of the vehicle, and therefore the engine speed, and the inferred second fluid pressure signal decrease to a level that causes release (disengagement) of the drive-away clutch;
The engine runs at idle speed unless the accelerator is depressed. If the vehicle then descends the slope even faster without the accelerator pedal being operated, the second fluid pressure signal remains too low to cause engagement of the drive-away clutch as desired. The engagement of the drive-away clutch, which is critical for safety reasons under these conditions, is therefore effected by the first fluid pressure signal, which is dependent on the vehicle speed and therefore increases.

According to another feature of the invention, a device for influencing a control device dependent on the position of the accelerator pedal of the vehicle in such a manner that upon further depression of the accelerator pedal, engagement of the clutch occurs at a higher engine speed. will be provided. A deeper depression of the accelerator pedal is taken as a signal reflecting an intention to drive away sooner. Engagement of the drive-away clutch at higher engine speeds facilitates earlier departures.

In order to explain the invention, one embodiment will be described below by way of example with reference to the accompanying drawings, in which: FIG.

The input shaft 1 is connected to the primary pulley 2 via the clutch 6.
is combined with The clutch 6 consists of a disc 7,
The disc 7 may be clamped by the cylinder 9 by fluid pressure in the line 8 so as to couple the input shaft 1 to the primary pulley 2.

V-belt 10 is wound around pulleys 2 and 3. The running diameter of the belt 10 around the pulleys 2, 3 may be varied such that the transmission ratio of the primary pulley 2 to the secondary pulley 3 is adjustable.

The forward/backward switching mechanism 4 includes a gear 1 connectable to the secondary pulley 3 by a displaceable switching member 13.
1 and 12. This arrangement allows the output shaft 5 to be driven in one direction via gears 12, 14 and in the opposite direction via gears 11, 15, 16.

The drawing shows a first stationary pilot tube 20 terminating in a channel 21 connected to the primary pulley 2. An annular channel 21 closing radially from the outside is supplied with a fluid that rotates with the primary pulley 2 inside it. This allows pilot tube 20 to detect fluid pressure signals, which are communicated via line 22 to valve 26.

In a corresponding manner, the annular channel 23 is connected to the input shaft 1 and the second pilot tube 24
terminates in the channel such that it detects a second fluid pressure signal, which signal is routed via line 25 to valve 26.
transmitted to. The higher of the two fluid pressure signals is passed by valve 26 through line 27 to control valve 3.
Sent to 0.

The control valve 30 has a valve body 31 loaded on one side by a spring 32 and on the other side by the fluid pressure in a space 33, the fluid pressure in the space being 2. The pressure of the higher of the two fluid pressure signals. Fluid is supplied via line 34 at a pressure sufficient to effect engagement of clutch 6. Depending on the position of the valve body 31, either fluid is routed from line 34 via line 8 to clutch 6, or line 8 is coupled to discharge line 35 such that clutch 6 is released. It is.

When the fluid pressure sensed by one of the pilot tubes 20, 24 is high enough, the valve body moves to the right such that the fluid pressure in line 34 is capable of effecting engagement of the clutch. is obvious.
As a result, the drive-away clutch 6 is engaged at both sufficient engine speed (pilot tube 24 fluid pressure signal) and sufficient vehicle speed (pilot tube 20 fluid pressure signal).

The spring 32 may be preloaded via an operating member 40 that contacts an operating cam 41 rotatable about a pivot 42 . The rotation of the cam 41 may be coupled to the displacement of the accelerator pedal in such a way that upon deeper depression of the vehicle's accelerator pedal, the cam rotates to the right and the spring 32 is therefore more preloaded. In this case, a higher fluid pressure in the space 33 is required to effect clutch engagement, so that this engagement
occurs with a high fluid pressure signal in line 27, resulting in
Occurs at high engine speeds.

[Brief explanation of drawings]

The drawing shows a schematic representation of an embodiment of the invention having an input shaft 1, a primary pulley 2, a secondary pulley 3, a forward/backward switching mechanism 4, and an output shaft 5. 1... Input shaft, 2... Primary pulley, 6... Clutch, 20... First stationary pilot tube, 2
DESCRIPTION OF SYMBOLS 1... Annular channel of pulley, 23... Annular channel of clutch, 24... Second pilot tube, 26... Valve, 30... Control valve.

Claims (1)

Claims: 1. A primary (drive) pulley connected to an annular channel that closes radially from the outside and that controls the pressure of the fluid present in the channel so as to produce a fluid pressure signal that depends on the rotational speed of the primary pulley. A motor vehicle transmission comprising: a continuously variable V-belt transmission having a stationary pilot tube terminating in the channel for sensing; and an input shaft connectable to the primary pulley via a drive-away clutch. The away clutch comprises a wet plate clutch operated by fluid pressure, the input shaft being coupled to a second annular channel closing radially from the outside, and a second stationary pilot tube adapted to the rotational speed of the input shaft. terminating within the second channel to detect the pressure of the fluid present in the second channel so as to produce a second fluid pressure signal dependently on the second fluid pressure signal, and successively transmitting the higher of the two fluid pressure signals. A transmission comprising a valve and a control device for regulating the fluid pressure used to operate the wet plate clutch in dependence on a transmitted fluid pressure signal. 2. that upon further depression of the accelerator pedal of the vehicle, the control device is influenced depending on the position of the accelerator pedal in such a way that engagement of the clutch occurs at higher engine speeds; A transmission device according to claim 1, characterized in: