WO2006031118A1

WO2006031118A1 - Clutch device

Info

Publication number: WO2006031118A1
Application number: PCT/NO2005/000253
Authority: WO
Inventors: Lucien LÉNÉRAND
Original assignee: Kongsberg Automotive As
Priority date: 2004-09-17
Filing date: 2005-07-04
Publication date: 2006-03-23
Also published as: SE0402271L; SE528205C2; SE0402271D0

Abstract

An actuator device for a clutch, where the clutch is enclosed by a clutch housing located between the vehicle's engine and a gearbox enclosed by a gearbox housing. The gearbox comprises a plurality of gear wheels, and a shift mechanism to which information concerning gear selection is transmitted from the gear operating unit, where the shift mechanism is equipped with one or more shift forks connected to some of the gear wheels for performing a gear shift. The actuator device comprises an actuator part and a valve unit for controlling the actuator part, where the valve unit is located in such a manner that it forms a part of the gearbox's shift mechanism.

Description

Clutch device

The present invention relates to an actuator device for moving a clutch respectively out of an engaged position in order to break the rotational transmission between an engine's driving shaft and a driven shaft, or into an engaged position in order to establish rotational transmission between the engine's driving shaft and the driven shaft. The clutch's actuator device comprises an actuator part and a valve unit for control of the actuator part.

The clutch is enclosed by a clutch housing and a gearbox which is enclosed by a gearbox housing. The clutch is located between the vehicle's engine and the gearbox. The gearbox comprises a plurality of gear wheels, possibly with associated shift sleeves and synchronising mechanisms or other means suitable for establishing a connection between some of the gear wheels and shift forks that form part of a shift and control unit hereinafter called a shift mechanism. The shift mechanism is included in the gearbox and receives information concerning gear selection from the gear operating unit. This information determines which of the shift forks have to be moved to perform a gear shift, thereby determining with which gear ratio power should be transmitted from the engine to the vehicle's driving wheels. Information may be transmitted to the shift mechanism concerning manual gear selection or automatic gear selection. The function and degree of complexity of the shift mechanism may vary depending on the type of gearbox and gear system in which it is to be employed.

According to the prior art various types of actuator devices are employed for operating the clutch. While clutch operation in private cars is often carried out by transfer of pressurised fluid from a master cylinder at the clutch pedal to a slave cylinder at the clutch, in heavier vehicles it will often be necessary to introduce a power-amplifying unit such as a servomechanism in order to facilitate the operation of the clutch.

The use is known of a servomechanism which is directly attached to the clutch housing and connected to a master cylinder at the clutch pedal. The actuator device receives a pressurised fluid from the master cylinder and additional pressurised fluid is supplied to the actuator part from a reservoir depending on supply of fluid from the master cylinder or the position of the pedal. A further known arrangement is to connect a servomechanism directly to the master cylinder, where pressurised fluid is transferred to a concentric slave cylinder at the clutch. Alternatively, the actuator device may be provided as a separate unit (In-Line Booster) between master cylinder and clutch. From the actuator device pressurised fluid may be passed to a concentric central slave cylinder in the clutch housing.

Alternatively, a central slave may be employed with integrated servomechanism or servo valve placed on the outside as described, for example, in GB 2121504. In GB 2121504 it is shown how a duct for hydraulic fluid to the central slave is protected by placing the duct in an extension of the slave clamped between the clutch housing and the gearbox housing. In DE 19716600 a servo valve for a pneumatic central slave is described located partly inside and/or outside the clutch housing. SU 1594000 describes a combined pneumatic/hydraulic central slave with valve outside the clutch housing. In US 6234290 the servo valve mechanism is protected against transmission of excess pressure from the pedal master. In this publication a servo system is described where a central slave receives working pressure from a valve mounted thereon and controlled from a master cylinder at the clutch pedal. Similar systems are described in US 2001002642 and US 6196369. An example of an external clutch servomechanism is described in DE 3319899.

With regard to the solutions involving an external servomechanism and lever- operated clutch, the problem is that this solution takes up a relatively large amount of space and it is expensive. An external clutch servomechanism with a lever in the clutch housing occupies a great deal of space outside the clutch housing. This applies whether the clutch servomechanism is located at the clutch housing, attached thereto, at the pedal mounting or in other positions according to the prior art.

As employed at present, the clutch servomechanism is a separate unit where the price is not necessarily only dependent on the cost of the components, but also on logistics, storage space, service, etc.

A clutch servomechanism that is provided integrated in a central slave has removed the space problem, but introduces instead problems associated with unwanted fluids (mineral oil or brake fluid) inside the clutch housing in the event of a leak. In some situations the clutch housing will also have a very high internal temperature, thus making it difficult and expensive to design a valve unit that can be placed inside the clutch housing.

It is an object of the present invention to provide an actuator solution that takes up less space when placed in the vehicle, and possibly is cost and space-saving with regard to logistics and storage space. A further object of the present invention is to provide a solution that facilitates service of the actuator.

These objects are achieved by the invention as indicated in the present independent patent claim, with embodiments of the invention indicated in the following dependent patent claims. By integrating a part or the whole of the actuator device in the vehicle's gearbox, a space saving is achieved compared to the prior art. In the independent patent claim it is stated that the actuator device's valve unit is located in such a manner that it forms a part of the gearbox's shift mechanism. In addition to being a space-saving solution, the object is also achieved of reducing the number of parts.

According to a first embodiment of the invention the actuator device's actuator part may also be located in such a manner that it also forms a part of the shift mechanism. This solution will be particularly appropriate where a lever is employed for operating the clutch. Transmission of the actuator part's movement to the clutch's lever can be undertaken by a transmission part, preferably a rod element, connecting the actuator part and the clutch's lever.

According to a second embodiment of the invention the actuator device's valve unit may be located in such a manner that it forms a part of the gearbox's shift mechanism, while the actuator part is located in the clutch housing. The actuator part may then preferably be composed of a concentric slave cylinder. In a preferred second embodiment the valve unit controls the actuator part by devices for signal transmission provided between the gearbox and the clutch housing. These devices may be bores or pipes from the gearbox to the clutch housing for transfer of pressurised fluid. When dividing the actuator part and the valve unit it will be necessary to use a feedback, for example a position feedback or a power feedback. The feedback can be composed of an element preferably a rod element for detecting the position in which the various parts of the actuator part are located. In an embodiment of the invention the shift mechanism is arranged releasably in the gearbox so that the valve unit and possibly the actuator part are removed from the gearbox by removing the shift mechanism from the gearbox. With this solution it will be possible to repair and perform maintenance work on the actuator device without the need to carry out a comprehensive disassembly. Alternatively, the actuator device may be arranged in such a manner that the valve unit and/or the actuator part can be removed from the gearbox, while the shift mechanism remains in the gearbox.

In a preferred solution the actuator device is provided in such a manner that the transmission part or the feedback remain in position in the gearbox housing/clutch housing when removing the shift mechanism.

The valve unit and the actuator part contained in the actuator device may be composed of various types of components which are known per se, since it is their position in the gearbox and the necessary components and means for permitting this positioning that is the key feature of the invention. Thus both hydraulic and pneumatic solutions or a combination thereof may be employed in implementing the invention. By positioning the actuator device according to the invention, a common supply of compressed air can be achieved for the gearbox and the clutch servo. The number of parts can be reduced and there is less likelihood of error. Furthermore, any leakage from the hydraulic system into the actuator device will not contaminate the surrounding area.

It should be briefly mentioned here that the valve unit may be electropneumatically controlled by an electrical signal, or controlled by a hydraulic signal in the form of a change in pressure in the hydraulic fluid transferred from a master cylinder. More mechanical solutions, optical signals or fluid other than hydraulic fluid may also be employed.

The actuator part may, for example, be composed of a cylinder unit comprised of one or more cylinder cavities wherein is mounted a piston, possibly equipped with a piston rod.

Examples of the invention will now be described with reference to the figures, in which:

Figure 1 illustrates a first embodiment of the invention depicted by a sectional view through gearbox and clutch. Figure 2 is a perspective view of the shift mechanism and a sectional view through the actuator part.

Figures 3a, 3b, 3c are sectional views of the connection between the clutch's lever and the components located in the shift mechanism.

Figure 4 is a sectional view of a second embodiment of the invention where the connection between the clutch's slave cylinder and the components placed in the shift mechanism are illustrated.

In figure 1 a gearbox 1 is illustrated by gearbox housing Ia and shift mechanism 2. An actuator device illustrated here by an actuator part 1 is located integrated in the shift mechanism 2. A valve unit, which is not seen in figure 1, is also integrated in the shift mechanism 2. The actuator part 1 is composed of a hydraulic part Ia and a pneumatic part, illustrated here by piston Ib. The clutch's 3 lever 3a is connected to the actuator part 1 by a transmission part 4 in order thereby to transmit movement from the actuator part 1 to the clutch 3. The clutch's 3 clutch housing is illustrated by 3b. Figure 2 illustrates the shift mechanism 2 as seen from below. The shift mechanism 2 is shown equipped with shift forks 2a and the actuator part 1 is shown attached to the shift mechanism 2. The actuator part 1 has a slightly different design to that illustrated in figure 1, the hydraulic part Ia being mounted coaxially with the air piston Ib in order to minimise space requirements in the length. Figure 3a illustrates the shift mechanism located in the gearbox 1 with the lever 3a and transmission part 4 only illustrated schematically. Figures 3b and 3c illustrate examples of attachment of the clutch's lever 3a to the attachment mechanism 2 by means of a rod-shaped transmission part 4. The transmission part 4 is provided with a first cavity 4a at one end for receiving an end of the lever 3a and a recess 4b at its other end. The actuator part 1 (which is not shown in this figure 3a, 3b) can be attached to the transmission part 4 at the recess 4b. By means of this solution the attachment mechanism 2 including the actuator part 1 can easily be removed from the gearbox 1 , the actuator part 1 being lifted straight up from the groove 4b. In the example in figure 3b the transmission part 4 is shown attached to the clutch housing 3b or the common wall between the clutch wall and the gearbox housing. In the example illustrated in figure 3c the transmission part is shown attached both to the clutch housing 3b and the gearbox housing 1 a.

Figure 4 illustrates an embodiment where the valve unit 5 is shown attached to the shift mechanism 2. The actuator part 1 in the form of a pneumatic central slave cylinder comprising a cylinder cavity Ic and cylinder piston Ib is shown placed in the clutch housing 3b. The valve unit 5 transfers the desired quantity of pressurised pneumatic fluid to the actuator part's cylinder cavity Ic in order to move the cylinder piston Ib forwards or backwards, thereby bringing the clutch out of engagement or into engagement. The transfer of the pressurised fluid is carried out through non-illustrated bores or pipes/hoses extending from the gearbox to the clutch housing. In addition it is necessary to have a position feedback 6 illustrated here as a rod element connecting the valve unit 5 and the clutch 3.

Claims

1. An actuator device for a clutch, where the clutch is enclosed by a clutch housing located between the vehicle's engine and a gearbox enclosed by a gearbox housing, where - the gearbox comprises a plurality of gear wheels, and a shift mechanism to which information concerning gear selection is transmitted from the gear operating unit, where the shift mechanism is equipped with one or more shift forks connected to some of the gear wheels for performing a gear shift, - the actuator device comprises an actuator part and a valve unit for controlling the actuator part, characterised in that the valve unit is located in such a manner that it forms a part of the gearbox's shift mechanism.

2. An actuator device according to patent claim 1, characterised in that the actuator part is located in such a manner that it forms a part of the shift mechanism.

3. An actuator device according to one of patent claims 1-2, characterised in that a transmission part, preferably a rod element, connects the actuator part and the clutch's lever.

4. An actuator device according to patent claim 1 , characterised in that the actuator part is located in the clutch housing and is preferably constituted by a concentric slave cylinder.

5. An actuator device according to patent claim 4, characterised in that the valve unit controls the actuator part by means of devices for signal transmission that are provided between the gearbox and the clutch housing.

6. An actuator device according to patent claim 5, characterised in that a feedback, preferably a rod element, connects the valve unit and the actuator part.

7. An actuator device according to one of the preceding claims, characterised in that the shift mechanism is mounted releasably in the gearbox so that the valve unit and possibly the actuator part are removed from the gearbox when the shift mechanism is removed from the gearbox.

8. An actuator device according to one of the preceding claims, characterised in that the shift mechanism remains in the gearbox when the valve unit and the actuator part are removed. An actuator device according to one of the preceding claims, characterised in that the transmission part or the feedback remain in position in the gearbox housing/clutch housing when the shift mechanism is removed.