Bearing for a gearwheel which serves as a reversing gear and as a shiftable free gear

A transmission for a motor vehicle featured with an internal combustion engine has a helical reversing gear wheel, which is mounted on a dual-row cylinder roller bearing with left-hand cylinder rollers and with right-hand cylinder rollers, which are supported on the inside, in each case, on a circular centre rim in the reversing gear wheel. The left-hand cylinder rollers and the right-hand cylinder rollers are held in a bearing cage. The bearing cage is configured in such a way that the force flow for axial forces between the reversing gear wheel and its transmission shaft, omitting the bearing cage, is introduced through the centre rim and by way of end faces of the cylinder rollers directly adjacent thereto, through the opposing end faces of the cylinder rollers and through adjacent components into the input shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National-Stage entry under 35 U.S.C. §371 based on International Application No. PCT/EP2006/008382, filed Aug. 26, 2006, which was published under PCT Article 21(2) and which claims priority to German Application No. DE 10 2005 043 477.0, filed Sep. 13, 2005.

TECHNICAL FIELD

The invention generally relates to a transmission, and more particularly to a transmission with a specially configured main shaft.

BACKGROUND

Reversing pinions or idler pinions or idlers, which are located on a main shaft or intermediate shaft, are frequently used in transmissions for the forward and reverse operation of motor vehicles.

On the one hand, the mounting of the idler should withstand large radial forces that occur during use in first gear or in reverse gear. At the same time, large axial forces occur in helical idlers.

DE 103 453 50 A1, JP 1 120 432 and DE 103 298 70 deal with the absorbing of axial forces such as occur in transmissions. DE 218 844 A1, JP 9 049 526 and DE 4 332 038 A1 show radial bearing cages which are configured such that the radial bearing can also absorb axial forces.

At least one object of the invention is to provide a loadable transmission which only has a small overall size. Other objects, desirable features and characteristics will become apparent from the subsequent summary, detailed description, and appended claims, taken in conjunction with the accompanying drawings and forgoing technical field and background.

SUMMARY

This object and other objects are achieved with an internal combustion engine, wherein the transmission has an input shaft, an output shaft and main shafts, on which transmission gear wheels are arranged, which in each case form gear pairings and of which at least one can be selectively locked by means of a selector sleeve on its respective transmission shaft, wherein one of the gear wheels is configured as a helical reversing gear wheel and can be engaged selectively for a forward gear pairing or for a reverse gear pairing, wherein the reversing gear wheel is mounted on a dual-row cylinder roller bearing with left-hand cylinder rollers and with right-hand cylinder rollers, which are supported on the inside, in each case, on a circular centre rim in the reversing gear wheel, the left-hand cylinder rollers and the right-hand cylinder rollers being held in a bearing cage, the bearing cage being configured in such a way that the force flow for axial forces between the reversing gear wheel and its transmission shaft, omitting the bearing cage, is introduced through the centre rim and by way of end faces of the cylinder rollers directly adjacent thereto, through the opposing end faces of the cylinder rollers and through adjacent components into the input shaft. This object and other objects are also achieved with an internal combustion engine, wherein the transmission has an input shaft, an output shaft and main shafts, on which transmission gear wheels are arranged, which in each case form gear pairings and of which at least one can be selectively locked by means of a selector sleeve on its respective transmission shaft, wherein one of the gear wheels is configured as a helical reversing gear wheel and can be selectively engaged for a forward gear pairing or for a reverse gear pairing, wherein the reversing gear wheel is mounted on a dual-row cylinder roller bearing with left-hand cylinder rollers and with right-hand cylinder rollers, which are supported on the inside in each case on a circular centre rim in the reversing gear wheel, the left-hand cylinder rollers and the right-hand cylinder rollers being held in a two-part bearing cage, the bearing cage parts of which are snapped into one another in a connecting region.

The invention proceeds, in this case, from the recognition that the known designs can be improved in that the mounting of the idler is configured in a special manner.

On the one hand, dual-row cylinder roller bearings, the cage of which is divided, are used instead of needle bearings. The cage halves can be snapped into one another. This produces simple assembly of the transmission because the idler placed on the main shaft can be provided with the two bearing halves. The cage halves are generally bearing cage parts here which can be snapped into one another in a connecting region.

In this case, a bearing cage part may have a peripheral groove in the connecting region. If the other bearing cage part, in the connecting region, has at least one flexible holding lug which, when the two bearing cage parts are assembled, is snapped into the groove, a particularly simple design is produced.

A centre rim in the idler between the two bearing halves provides a transmission of the axial forces from the idler to the bearing bodies.

In contrast to the prior art, at least some end faces of the cylindrical bearing bodies received in the bearing cage should not rest on the bearing cages themselves, which are in turn supported on the adjacent faces in the transmission. In the invention, axial forces are passed directly by way of the bearing bodies to adjacent support faces in the transmission, and specifically without loading the bearing cage.

If an idler mounting of this type is used a great load carrying ability and a low overall size are produced with simultaneously low production costs.

DETAILED DESCRIPTION

FIGS. 1 and 2show a transmission for a motor vehicle with an internal combustion engine. The transmission has an input shaft E or1, an output shaft A and two main shafts HW located one above the other.

A large number of transmission gear wheels which in each case form pairings for the gears1to6is arranged on these transmission shafts. The gear order number is given in each case on the relevant gear wheel pairing inFIG. 2. Connections between the transmission wheels and the gear shafts are produced by means of selector sleeves, not shown.

One of the gear wheels for the “first gear” namely the gear wheel4is used as a so-called “idler”. The mounting of this idler gear wheel4is shown more precisely inFIG. 3. Reference numerals are shown in a cornered box.

As can be seen there, the idler4is radially mounted on two cylinder rollers7,8which are supported on the inside on a circular shoulder9, in each case. This shoulder9is also called a “centre rim”.

During operation, if the idler gear wheel4is being used as a deflector wheel for the reverse gear “R”, the latter rotates on the input shaft1, specifically with a radial mounting arrangement by means of the cylinder rollers7and8, which are held in a bearing cage14.

In addition to the radial forces, axial forces then occur because the idler gear wheel4is actually helical. These axial forces are introduced by way of the centre rim9and—differently, depending on the direction of the axial force—by way of the end faces of the cylinders rollers7or8into the input shaft1. In the view inFIG. 1, to introduce this axial force, either the inner ring2of an adjacent tapered roller bearing is used or, on the other side, the adjacent inner ring of a sleeve carrier6. The force flow is made clear here by a closed force line13. As is clearly seen, the axial forces are not transmitted by way of the bearing cage14.

The bearing cage14is configured in two parts, it being possible to snap the two halves together by means of a snap connection15. The left-hand bearing cage part has a peripheral groove here in the connecting region15. The right-hand bearing cage part has, in the connecting region15, flexible holding lugs, which are snapped into the groove when the two bearing cage parts are assembled.

This snapping in of a bearing cage of a needle bearing plays a part in the invention inasmuch as the cylinder roller bearings7and8are also snapped together during assembly with their cage halves in order to form a unit that is easy to handle together with the idler gear wheel4. The idler4when placed on the input shaft1can also be retrospectively provided with the cage halves.