DEVICE FOR VEHICLE TRANSMISSION

Abstract: A device for manoeuvering a clutch in vehicle transmissions where the two shank ends (2) of a clutch release lever (1) cooperate with engagement surfaces (3) of a pulling throwout bearing (4). The clutch release lever is rotatably arranged about an axis of rotation (5) using a suspension means (6) which is shaped like a spherical radial bearing. This allows the clutch release lever (1) to be rotated about the axis of rotation (5) so that the clutch release lever, during connection of a gearbox with an installed clutch release lever onto a clutch with an installed throwout bearing (4), is not blocked by the throwout bearing whilst, simultaneously, the axis of rotation (5) may be inclined with respect to the input shaft (17) of the gearbox.

Description: DEVICE FOR VEHICLE TRANSMISSION TECHNICAL FIELD: The present invention relates to a device for vehicle transmissions for manoeuvering a vehicle clutch, i.e. switching between an engaged position and a disengaged position, according to the preamble of claim 1. BACKGROUND OF THE INVENTION: A device for vehicle transmissions for the manoeuvering of a vehicle clutch typically comprises the following components: a clutch release lever, carried in the gearbox and cooperating with a throwout bearing which, in turn, actuates the clutch itself. The clutch release lever generally has two shanks which bear on engagement surfaces on the throwout bearing. The clutch is rotatably arranged on the same shaft as a flywheel while a clutch disc is pressed against the flywheel by a pressure plate which is spring-biased by a diaphragm spring. The pressure plate, in turn, is operated by the throwout bearing via the diaphragm spring. It is known to utilize a vehicle clutch having a pulling throwout bearing cooperating with a clutch release lever which is fastened on a rotatable axle. In clutches having pulling throwout bearings, the bearing is directly coupled to the clutch mechanism and, thus, to the engine, whilst the axle having the clutch release lever is carried in the gearbox housing. This division creates problems when joining the gearbox to the engine, for example in connection with repairs, when the gearbox has to be mounted onto an engine already installed in the vehicle. The reason is that the shanks of the clutch release lever will have to be rotated in behind the engagement surfaces of the throwout bearing at the same time as the input shaft of the gearbox is inserted into a centre of the clutch disc and a guiding sleeve is inserted into the throwout bearing. The rotating movement of the lever axle will then have to be coordinated with the axial displacement of the gearbox, which is difficult because the throwout bearing and the lever are hidden by a clutch bell-housing when they are in position for beginning engagement. Thus, the mechanic cannot perform this synchronization in other ways than to feel his/her way without seeing the relative position of the components. According to SE-B-451 211, a rotatable axle is carried in a clutch bell-housing using two fulcrum points. A clutch release lever is fastened on the axle and cooperates with a throwout bearing. By rotating the axle, the bearing will be subjected to a pulling force in the direction of disengagement via the lever. An intercepting device is connected with the bearing in order to catch the shanks of the lever, during joining of the gearbox to the engine, and to steer the ends of the lever to engagement with engagement surfaces of the throwout bearing. The intercepting device is formed by a brace made of spring steel. Because the clutch has been provided with an intercepting device, it is sufficient if the mechanic places the lever in a predetermined, downwardly angled mounting position. When the gearbox thereafter is slid in place, the lever is automatically steered to the proper position behind the engagement surfaces of the throwout bearing. This construction is stable and provides a guaranteed operation, but it has the disadvantage that it cannot compensate for misalignment of the axle and mounting errors regarding the relative positions of the gearbox and engine. The consequence may be an uneven distribution of forces in the lever which will result in increased wear and functional dis- turbances. Different alternative solutions of the problem associated with guiding the lever during mounting of a gearbox onto an engine, also called docking, have been proposed. They all have in common that they utilize some type of throwout bearing having a catch. The throwout bearing is installed temporarily on the input shaft of the gearbox, with the clutch release lever in operating position, so that it is automatically fixedly snapped onto the diaphragm spring of the clutch during assembly. These solutions are disting- uishably more expensive and have an inferior reliability than the solution according to SE-B-451 211. In order to compensate for misalignment of the clutch release lever, the lever may be spherically carried in an axial uniball bearing. According to US-A-4 860 870, the clutch release lever is mounted in a support point which has a cylindrical support surface which cooperates with a corresponding support surface on the clutch release lever. This arrangement is claimed to compensate for the misalign- ment which may occur during assembly or operation. These axial uniball bearings allow a limited movement in all directions, i.e. they cannot rotate a full revolution about any axis, which results in the lever not being able to be angled sufficiently much to allow a docking according to SE-B-451 211. Therefore, a docking procedure according to the above described solution is required where a throwout bearing having a catch is utilized. SUMMARY OF THE INVENTION: A main object of the invention is therefore to provide a device which compensates the misalignment which might be present during assembly or operation of a gearbox on an engine, whilst the device simultaneously allows the clutch release lever to be angled down sufficiently from the throwout bearing so that the clutch release lever and the throwout bearing do not collide during assembly of the gearbox to the engine. These objects are accomplished according to the present invention by a device according to claim 1. Preferred embodiments of the present invention are described in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS: The invention will be described in greater detail below by way of example only and with reference to the annexed drawings, in which: Fig. 1 is a schematic sectional view of a clutch release lever according to the present invention; Fig. 2 is a schematic sectional view of a part of a vehicle clutch, where the gearbox with a mounted clutch release lever is in a position to be slid in towards the clutch with a mounted throwout bearing, according to the present invention; Fig. 3 is a schematic sectional view of a part of a vehicle clutch, where the gearbox is fully slid in towards the clutch, according to the present invention; Fig. 4 is a schematic sectional view along the line IV-IV of Fig. 3, and Fig. 5 is a schematic sectional view of a typical, known spherical radial bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: Fig. 1 shows a clutch release lever 1 according to the invention. The clutch release lever 1 has a first end 18 which is forked into two shank ends 2, a second end 16 and a longitudinal axis 15 which runs from said first end 18 to said second end 16. Figs. 2 and 3 show a device according to the invention for manoeuvering the clutch of vehicle transmissions wherein the two shank ends 2 of a clutch release lever 1 cooperate with engagement surfaces 3 on a pulling throwout bearing 4. The clutch release lever 1 is rotatably arranged about an axis of rotation 5 using a suspension means 6 which is in the shape of a spherical radial bearing. The suspension means 6 is attached to a protrusion 19 from the gearbox, this protrusion is marked with a broken line in Figs. 2-3. This suspension means 6 makes it possible to rotate said clutch release lever 1, on the one hand to an assembly position during mounting of a gearbox with an affixed clutch release lever onto a clutch with an affixed throwout bearing 4 where said shank ends 2 are positioned so that they clear said throwout bearing 4 during axial displace- ment of the gearbox towards the clutch and, on the other hand to rotate to a rest position where said shank ends 2 cooperate with said throwout bearing 4 and, lastly, to rotate from said rest position to a clutch release position. This suspension means 6 thus makes it possible to simultaneously rotate the clutch release lever 1 about the axis of rotation 5 and to angularly adjust it a predetermined angle with respect to the input shaft 17 of the gearbox, i.e. the angle between the input shaft 17 and the axis of rotation 5 will be able to differ from 90°. The throwout bearing 4 is further provided with an intercepting device 7, which has guidance surfaces 8 arranged to catch the shank ends 2 of the clutch release lever, set in the assembly position, during connection of a gearbox having said clutch release lever 1 installed onto a clutch with an installed throwout bearing, when the gearbox is axially displaced towards the clutch and, during continued axial displacement, make the clutch release lever rotate about the axis of rotation 5 and steer the shank ends into engagement with the engagement surfaces of the throwout bearing. This latter position is shown in Fig. 3. According to Fig. 4, the throwout bearing 4 has diametrically opposed wing-shaped protrusions 9 which have engagement surfaces 3 for cooperation with the two shank ends 2 of the clutch release lever. The intercepting device 7 consists of a metal wire loop 10 which has its ends fastened in the respective protrusions 9. As is shown in Figs. 2-4, the intercepting device 7 has elastic means 11, which, in the engaged position of the clutch release lever, spring-bias the shank ends 2 towards the engagement surfaces 3 of the throwout bearing. The metal wire loop 10 is advantageously made of spring steel and the elastic means 11 may comprise screw-wound parts. A typical example of already known spherical radial bearings is shown in Fig. 5. These spherical radial bearings may be made as spherical ball bearings, spherical roller bearings or spherical slide bearings. A spherical slide bearing is shown in Fig. 5. A bearing of the spherical radial bearing type has three degrees of freedom for movements, one degree of freedom allows a complete revolution about a certain axis. According to the invention, this degree of freedom is utilized for axial rotation of the clutch release lever about the axis of rotation 5, the other two degrees of freedom are utilized for inclination of the axis of rotation 5 of the clutch release lever so that the angle between the input shaft 17 of the gearbox and the axis of rotation 5 may differ from 90°. The bearing means for rotation of the clutch release lever 1 about the axis of rotation is marked 12. The bearing parts 13 and 14 cooperate to achieve a certain freedom of movement for inclination of the axis of rotation 5 with respect to the input shaft 17 of the gearbox. Whilst the invention has been described above with respect to certain preferred embodiments thereof, the invention is not limited to these but may be varied widely within the scope of the appended claims. For example, the elastic means of the intercepting device does not have to be arranged as a wire loop, but may be made of, for example, spring steel strip.

Claims: CLAIMS : 1. A device for vehicle transmissions which comprises an input shaft (17) to a gearbox and a device (1, 4) for manoeuvering a clutch, where said device (1, 4) for manoeuvering a clutch compri- ses a clutch release lever (1) having a first end (18) which is forked into two shank ends (2), a second end (16) and a longitudinal axis (15) which runs from said first end (18) to said second end (16), and a pulling throwout bearing (4) having engagement surfaces (3) which cooperates with said shank ends (2), where said clutch release lever (1) is rotatably arranged about an axis of rotation (5) using a suspension means (6), so that said clutch release lever (1), on the one hand, may rotate from an assembly position during mounting of a gearbox with an affixed clutch release lever onto a clutch with an affixed throwout bearing (4) where said shank ends (2) are positioned so that they clear said throwout bearing (4) during axial displacement of the gearbox towards the clutch and, on the other hand to rotate to a rest position where said shank ends (2) cooperate with said throwout bearing (4) and, lastly, to rotate from said rest position to a clutch release position, where said throwout bearing (4) is provided with an inter- cepting device (7), which has guidance surfaces (8) arranged to catch the shank ends (2) of the clutch release lever, set in said assembly position, during connection of a gearbox having said clutch release lever (1) installed onto a clutch with an installed throwout bearing (4), when the gearbox is axially displaced towards the clutch and, during continued axial displacement, make said clutch release lever rotate about said axis of rotation (5) and steer said shank ends (2) into engagement with said engagement surfaces (3) of said throwout bearing, characterized in that said suspension means (6) is a spherical radial bearing which makes it possible to rotate said clutch release lever (1) to said assembly position and to angularly adjust said axis of rotation (5) of said clutch release lever (1) so that the angle between said axis of rotation (5) and said input shaft (17) of said gearbox may differ from 90°. 2. A device according to claim 2, characterized in that said throwout bearing (4) has diametrically opposed wing- shaped protrusions (9) which have engagement surfaces (3) for said clutch release lever, and that said intercepting device (7) comprises a metal wire loop (10) which has its ends fastened in the respective protrusions (9). 3. A device according to one of claim 1 or 2, charac- terized in that said intercepting device (7) comprises elastic means (11) which, in the engaged position of said clutch release lever (1), spring-bias said shank ends (2) towards said engagement surfaces (3) of said throwout bearing. 4. A device according to one of claim 1 or 2, characterized in that said spherical radial bearing comprises a spherical radial roller bearing.

Inventors: BOERJESSON TORE, BOERJESSON, TORE
Applicants: BOERJESSON TORE, VOLVO LASTVAGNAR AB, BOERJESSON, TORE
Application year: 1997
Main classification: F16D23
IPC codes: F16D23