GB2133094A

GB2133094A - Cone clutch

Info

Publication number: GB2133094A
Application number: GB08330678A
Authority: GB
Inventors: Fritz Bernau; Manfred Heiber; Jurgen Rathke; Sabine Tenbusch; Dieter Schneider; Gunther Villwock; Ullrich Rogge
Original assignee: IFA GETRIEBEWERKE BRANDENBURG
Current assignee: IFA GETRIEBEWERKE BRANDENBURG
Priority date: 1982-12-27
Filing date: 1983-11-17
Publication date: 1984-07-18
Also published as: GB8330678D0; HUT34591A; SE8307078D0; DE3341147A1; HU189380B; FR2538482A1; SE8307078L

Abstract

A cone clutch for use in synchronising equipment of a gear transmission, comprises a hardened steel sleeve (3) with a frustro-conical internal surface (5), and an aluminium alloy cone (1) with a frustro-conical external surface (2) formed with grooves (4), the sleeve and the cone being relatively movable to effect frictional coupling thereof at the two surfaces (2, 5). The alloy has a maximum Brinell hardness of 130 and its constituents include silicon, copper, nickel, magnesium, manganese and titanium. <IMAGE>

Description

SPECIFICATION Cone clutch The present invention relates to a cone clutch, especially a clutch for use in synchronising equipment of a gear transmission.

Friction clutches are required in gear transmission synchronising equipment in which, for effecting synchronisation, components of the equipment interengage at conical friction surfaces and enable synchronisation of relatively rotating gears during a gear change operation.

Known synchronisng devices include friction couplings with different sliding friction materials, for example special brasses, bronzes, molybdenumcoated, oxide-coated or multisubstance-coated surfaces such as plastics materials, which rub against a hardened steel surface. Groove-shaped depressions are present in the sliding friction metal and/or in the hardened steel surface and serve for the removal of oil from the contact surfaces and for improving the friction value in the mixed friction range.

The known devices have the following disadvantages: - low stability of shape of the surface provided with grooves in the case of the use of special brasses and bronzes, whereby wear and operating failure occur; - high material costs and increased production effort with the use of molybdenum coating; - increased production effort in the case of surfaces coated with oxide or multiple substances; - low temperature resistance and stability of shape in the case of plastics substances; and - high wear at the counter-cone of hardened steel with the use of surfaces coated with molybdenum, oxide or hard substances, whereby operating failure may occur.

it would thus be desirable to provide a friction coupling device in which, during the friction operation, almost no wear arises and in the manufacture of which the sliding friction material is easily processable, low material costs are entailed and an additional coating is not required.

According to the present invention there is provided a cone clutch comprising an aluminium alloy first element having a grooved frustro-conical coupling surface and a hardened steel second element having a smooth frustro-conical coupling surface complementary to the envelope of the grooved coupling surface, the alloy including 11 to 23% of silicon, 1 to 3.5% of copper, 0.8 to 2.7% of nickel, up to 1.5% of magnesium, up to 0.5% of manganese and up to 0.2% of titanium and having a Brinell hardness of at most 130, and the clutch being so arranged that the elements are relatively movable for frictional coupling thereof at said coupling surfaces with the second element either loaded exclusively in compression or so loaded in both compression and tension that such loadings substantially cancel each other.

In a preferred embodiment there is provided a friction coupling in a synchronising device for a toothed wheel speed-change gear, in which for the production of the synchronising operation, components of the synchronising device act on each other by conical friction surfaces and on the principle of a friction clutch produce the synchronism of relatively rotating gear components during a gear change operation. The frictional coupling comprises a sliding friction cone of an aluminium alloy with the main alloy components of silicon (11 to 23%), copper (1 to 3.5%), nickel (0.8 to 2.7%), magnesium (up to 1.5%), manganese (up to 0.5%) and titanium (up to 0.2%) and having a Brinell hardness of at most 1 30 HB and thus adequate compression strength even at higher temperatures.At its conical surface, the cone has grooves for the removal of oil and during the friction operation is loaded exclusively in compression, or by compression and tension loadings which cancel each other out.

The coupling further comprises a counter-cone of hardened steel with a smooth, for example ground, conical surface and loaded in tension or compression during the friction operation, wherein during the frictional contact of both these materials under the arising thermal conditions, a chemo-physical reaction takes place which leads to the formation of a metallic protective film and thereby almost completely prevents the frictional wear at the contact surfaces.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a sectional view of part of a first cone clutch embodying the invention; and Fig. 2 is a sectional view of part of a second cone clutch embodying the invention.

Referring now to the drawings, there is shown in Fig. 1 part of a cone clutch comprising a sliding friction cone 1 of aluminium alloy provided with grooves 4 for the removal of oil in a frustro-conical surface 2 thereof, and a counter-cone 3 which is frictionaily engageable with the cone 1 at a frustro-conical surface 5 of the cone 3. The alloy has main alloy components of silicon (11 to 23%), copper (1 to 3.5%), nickel (0.8 to 2.7%), magnesium (up to 1.5%), manganese (up to 0.5%) and titanium (up to 0.2%) and has a Brinell hardness of at most 130 HB, whereby an adequate compression strength is ensured even at higher temperatures. Since this material possesses only iow tensile strength, it is subject exclusively to compression stress during the frictional operation.The counter-cone 3 consists of hardened steel and its frustro-conical surface 5 is smooth, for example ground. This component is loaded in tension during the frictional coupling.

During the frictional contact of the constituent materials of the two cones under the arising thermal conditions, a known complex of chemophysical processes devolves, as a result of which a metallic protective film forms, which almost compietely prevents a frictional wear at the contact surfaces.

In Fig. 2, the sliding friction cone 1 of aluminium alloy, which is disposed in frictional contact with the counter-cone 3, is sleeve-shaped and additionally possesses a frustro-conical surface 6 at its internal circumference, the surface 6 being frictionally engageable with a countercone 7 and being provided with grooves 8 for the removal of oil. Compression and tension loading cancel out in this arrangement. The counter-cone 3 consists of hardened steel and possesses a smooth, for example ground, conical surface 5 as the contact surface for the conical surface 2. This component is loaded in compression during the frictional coupling.

The cone clutch can be used not only in synchromesh gearboxes, but also in other applications where friction coupling is required.

Claims

1. A cone clutch comprising an aluminium alloy first element having a groove frustro-conical coupling surface and an hardened steel second element having a smooth frustro-conical coupling surface complementary to the envelope of the grooved coupling surface, the alloy including 11 to 23% of silicon, 1 to 3.5% of copper, 0.8 to 2.7% of nickel, up to 1.5% of magnesium, up to 0.5% of manganese and up to 0.2% of titainium and having a Brinell hardness of at most 130, and the clutch being so arranged that the elements are relatively movable for frictional coupling thereof at said coupling surfaces with the second element either loaded exclusively in compression or so loaded in both compression and tension that such loadings substantially cancel each other.

2. A cone clutch as claimed in claim 1, wherein the smooth coupling surface is provided by a ground surface of the second element.

3. A cone clutch substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

4. A cone clutch substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

5. A synchromesh gear transmission comprising a cone clutch as claimed in any one of the preceding ciaims operable to synchronise gears of the transmission.