JPH08261311A - Shaft support structure for transmission - Google Patents

Abstract

PURPOSE: To absorb thermal expansion difference between a transmission case and a shaft which are made of different materials by constituting a spacer, which is provided between a tapered roller bearing and a shim, of the inside first space piece having a tapered face and the outside second space piece engaging therewith. CONSTITUTION: A tapered roller bearing 4 which is inserted into the inside diameter of a light alloy case 1 and supports a shaft 2 is provided with an appropriate clearance in the axial direction in an outer race 4a by a retainer 5, which is fastened to the case 1 by a bolt, via a shim 6 and a ring spacer. In this case, the spacer is composed of the first space piece 8, which is made of a material having large thermal expansion coefficient and provided with a tapered face radially outward, and the second space piece 9, which is made of a material having small thermal expansion coefficient and engaged with the tapered face of the first space piece 8 radially inward. This constitution allows to absorb the difference in thermal expansion between the case 1 and the shaft 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a steel shaft in a case of a vehicle transmission, supports the shaft with a taper roller bearing, and provides a shim for absorbing a difference in axial length. Transmission shaft support structure.

[0002]

2. Description of the Related Art The overall structure of a transmission is shown in FIG. A main shaft 2 and a counter shaft 3 are supported by a tapered roller bearing 4 in a case indicated by reference numeral 1. In order that the tapered roller bearing 4 positions the shafts 2 and 3 in the axial direction and bears the load, a shim 6 is provided to adjust the difference in axial length and provide an appropriate gap.

A conventional example of the counter shaft 3 shown in FIG. 4 will be described below. The counter shaft 3 having the gears mounted thereon is supported by a tapered roller bearing 4 fitted in the cases 1A and 1B, and is a side surface of the outer race in the axial direction, one end of which is the case 1A and the other end of which is bolted to the case 1B. It is positioned by the attached retainer 5. A shim 6 is inserted between the outer race 4a of the bearing and the retainer 5 in order to adjust the difference in axial length between the cases 1A and 1B and the shaft 3 and to provide a proper gap. The thickness of the shim 6 to be selectively used is set at a pitch of about 0.05 mm in order to set the gap to an appropriate value.

However, in the recent demand for higher performance, Case 1
Aluminum alloys and other light alloy castings are being used in the market. In this case, unlike the case of combining a cast iron case and a steel shaft with the conventional structure, the difference in linear thermal expansion coefficient between the aluminum alloy material and steel causes the taper roller bearing The gap will deviate from the proper value, and problems will occur.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shaft support structure which absorbs a difference in thermal expansion between a light alloy cast transmission case and a steel shaft in combination.

[0006]

SUMMARY OF THE INVENTION The present invention is a transmission in which a steel shaft is provided in a case, the shaft is supported by a tapered roller bearing, and a shim for absorbing a difference in axial length is provided. In the shaft supporting structure of No. 1, the case is made of a light alloy casting, and a ring-shaped spacer is provided between the tapered roller bearing and the shim, and the spacer has a first inner surface having a tapered surface radially outward. A space piece and an outer second space piece having a tapered surface that engages with the tapered surface of the first space piece radially inward, the first space piece being relative to the second space piece. And a side surface having a larger radial thickness of both space pieces is sandwiched between the outer race and the shim of the tapered roller bearing.

Lubricating means is provided on the tapered surface of the spacer.

[0008]

According to the shaft supporting structure of the transmission configured as described above, the expansion amount varies with the temperature change due to the difference in the thermal expansion coefficient between the first space piece and the second space piece forming the spacer. The difference in the coefficient of thermal expansion between the light alloy case and the steel shaft causes a difference in the spacer width due to slippage on the engaged tapered surfaces, and the difference in the amount of thermal expansion in the axial direction. To offset.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a light alloy case, and a taper roller bearing 4 holding a shaft 2 in its inner diameter.
Has been inserted. The bearing 4 is made up of a shim 6 and a spacer 7 by means of a retainer 5 bolted to the case 1.
A proper gap is provided in the outer race 4a via the and.

The spacers 7 are both ring-shaped and are made of a material having a large coefficient of thermal expansion on the inner side, and the first space piece 8 having a tapered surface on the outer side in the radial direction and a material having a small coefficient of thermal expansion on the outer side. And a second space piece 9 having a taper surface that engages with the taper surface of the first space piece 8 inward in the radial direction. And
The spacer 7 is sandwiched between the shim 6 and the outer race 4a, with the side surfaces 8a and 9a of the two space pieces 8 and 9 having the larger radial thickness serving as the outer surface thereof.

The material of the first space piece having a small thermal expansion coefficient is aluminum alloy, synthetic resin, etc., and the material of the second space piece having a small thermal expansion coefficient is steel, cast iron or the like. Next, the operation will be described.

The details of the spacer 7 are shown in FIG.
At room temperature, the first and second space pieces 8 and 9 are assembled such that their respective tapered surfaces face each other as shown by hatching. Both space pieces 8 and 9 expand together as the oil temperature rises, but the amount of thermal expansion of the first space piece 8 is large, resulting in 8A shown by the chain line, whereas the taper of the outer surface of this first space piece 8 The amount of thermal expansion of the taper surface of the inner surface of the second space piece 9 facing the surface is small,
Moves to the position of 9A indicated by the chain line by sliding in the axial direction, and the width L of the spacer 7 increases to L + δ. Therefore, the thermal expansion of the light alloy case 1 and the steel shafts 2 and 3 is made by selecting the material of the space pieces 8 and 9 according to the coefficient of thermal expansion and the angle of the tapered surface 7a. Therefore, it is possible to offset the difference between the two and to provide a proper gap in the tapered roller bearing 4 without being affected by the oil temperature.

Further, on the tapered surface 7a of the spacer 7,
Applying molybdenum disulfide or providing lubrication means (not shown) such as inserting synthetic resin material with excellent lubricity can change radial displacement due to thermal expansion into axial displacement with less loss. It is effective.

[0015]

As described above, according to the present invention, in a transmission using a case made of a light alloy casting, the material of the space piece is selected according to its thermal expansion coefficient,
By setting the angle of the tapered surface to an appropriate value, it is possible to offset the difference in thermal expansion between the light alloy case and the steel shaft, and to provide an appropriate gap in the tapered roller bearing even with temperature changes. it can.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory view of the operation of FIG.

FIG. 3 is a sectional view showing the overall structure of a transmission.

FIG. 4 is a cross-sectional view showing a conventional shaft support structure for a transmission.

[Explanation of symbols]

 1, 1A, 1B ··· Case 2 ··· Main shaft 3 ··· Counter shaft 4 ··· Tapered roller bearing 4a ··· Outer lace 5 ... Retainer 6 ... Shim 7 ... Spacer 7a ... Tapered surface 8 ... First space piece 8a ..... Side surface with large radial thickness 9 .... Second space piece 9a ..... Large radial thickness Side

Claims (2)

[Claims] 1. A shaft support structure for a transmission, wherein a steel shaft is provided in a case, the shaft is supported by a taper roller bearing, and a shim for absorbing a difference in axial length is provided. A ring-shaped spacer is provided between the tapered roller bearing and the shim, which is made of a light alloy casting, and the spacer has an inner first space piece having a tapered surface radially outward and the first space piece. The first space piece is made of a material having a larger coefficient of thermal expansion than the second space piece, the second space piece having an outer side having a taper surface radially inwardly engaged with the taper surface of the space piece. The transmission is characterized in that the side surface of the formed space piece having a larger radial thickness is sandwiched between the outer race of the tapered roller bearing and the shim. Shaft support structure. 2. The shaft support structure for a transmission according to claim 1, wherein a lubrication means is provided on the tapered surface of the spacer.