GB2161245A - Spacer for transmission shaft - Google Patents

Abstract

An improved spacer for a transmission gear shaft facilitates axial locations of pairs of gears 32, 34 or bearings 16, 18 along the shaft. In a preferred form the spacer comprises an open coil member 20 which defines a helicoidal body portion resiliently disposed between a pair of bearings. In addition to axially locating the bearings relative to one another, the helicoidal body portion facilitates the flow of splash and spray oil along the shaft between the bearings. In the same preferred form, the spacer is made of a non-heat treated high carbon spring steel. <IMAGE>

Description

SPECIFICATION Spacer for transmission shaft Background of the invention This invention relates to spacer members positioned on transmission gear shafts for axially locating gears and bearings. The majority of standard or manually shifted transmissions are internally lubricated by "splash and spray" oil, whereby rotating members within the transmission housing extend into an oil sump at the bottom of the transmission housing and disperse oil over the internals of the transmission. Numerous efforts have been made to achieve satisfactory oil dispersions within the transmission housing; one of the more noteworthy being the use of troughs which receive oil thrown randomly for redirecting same to specific locations within the housing. One particular location of critical importance, for example, is the transmission pocket bearing.Another of such locations is the reverse idler shaft which is typically non-rotatable, but carries a reverse idler gear rotatable thereabout on needle bearings interposed between gear and shaft members. Typically, two such sets of needle bearings are utilized to support the rotation of the reverse idler gear. A spacer member is positioned between the sets of needle bearings to first axially locate the bearings, and then to insure proper rotational position of the bearings during operation. Typical spacers are generally tubular in design, and operate only to hold the bearings apart, providing no facilitation of lubrication of the bearings.

Summary of the invention The transmission gear shaft spacer disclosed herein provides a system whereby a flow of splash and spray oil along the shaft between the bearings is facilitated. In a preferred form, the spacer has squared ends which engage a pair of bearings supporting a rotatable reverse idler gear on a non-rotatable shaft. The spacer defines a helicoidal body of an open coil configuration, the squared ends providing radially uniform support surfaces resiliently disposed between the bearings. In a preferred form the helicoidal body is of a non-heat treated high carbon steel.

A second embodiment of a transmission gear shaft spacer defines a helicoidal body of a closed coil configuration disposed tightly between a pair of gears radially fixed to a gear shaft. The spacer provides axial positioning of the gears with respect to one another. The ends of the spacer are also squared in the second preferred form.

Brief description of the drawings Figure 1 is a cross sectional view of a transmission which employs two alternate preferred embodiments of the spacer of the present invention.

Figure 2 is an isolated side view, partly in section and in a free standing mode, of one of the preferred embodiments shown in Figure 1.

Figure 3 is a side view, also in a free standing mode, of the other preferred embodiment shown in Figure 1.

Detailed description of preferred embodiments Referring initially to Figure 1, a sectional view of a transmission 10 includes two separate alternate embodiments of spacers made in accordance with this invention at 20 and 30, respectively. The transmission 10 embodies a relatively standard configuration of manually shifted gears, the gears positioned on a mainshaft 8, a countershaft 14 and a non-rotatable reverse idler shaft 12. Each of the two spacers circumferentially encases a portion of a transmission gear shaft. The spacer 20 is of an open coil configuration, and circumferentially encases the reverse idler shaft 12, while the closed coil spacer 30 encases the countershaft 14.

The open coil spacer 20 is axially interposed on the reverse idler shaft 12 between a parallel set of bearings 16 and 18. In the preferred embodiment, the bearings are needle bearings, although the spacer of the invention described herein is suitable for use with other types or styles of bearings as well. The bearings 16 and 18 support a reverse idler gear 22, for rotation thereof about the reverse idler shaft 12 on the bearings 16 and 18.

Referring now particularly to Figure 2, the open coil spacer 20 defines a helicoidally shaped body portion 24, and has first and second squared ends 26 and 28, respectively. The squared ends 26 and 28 provide for radially uniform resilient support surfaces for contact with opposing inner ends 36 and 38 of respective bearings 16 and 18. In the preferred embodiment, the shaft will have an outside diameter slightly less than the inside diameter of the spacer. To the extent that the spacer is situated between the bearings 16 and 18, it will tend to rotate about the idler shaft 12 by virtue of friction drag forces imposed on the spacer ends 26 and 28 during rotation of the bearing inner ends 36 and 38 about the shaft 12. Thus the needle bearings 16 and 18 will frictionally cause the spacer 20 to rotate about the stationary reverse idler shaft 12.The resultant rotational movement of the helicoidal body portion 24 of the spacer 20 will produce as axial oil movement along the shaft 12 to facilitate lubrication of the needle bearings 16 and 18, which are not exposed directly to the splash and spray oil environment within the transmission 10.

It should be noted that the open coil spacer 20 may be disposed between the bearings 16 and 18 under a slight load; thus under a pre-loaded condition. It is suggested that the latter would insure continuous rotational movement of the spacer with the bearings about the non-rotating shaft 12. On the other hand, the spacer will move with the bearings withour such pre-load, and even if there is slight axial floating of the spacer between the bearings by virtue of viscous drag forces imposed on the spacer due to surface tension of the oil.

An alternate preferred embodiment of the spacer of the present invention is shown at 30 in Figure 3.

The spacer 30, however, is positioned (see Figure 1) between a pair of gears 32 and 34 located on the countershaft 14. The gears 32 and 34 are keyed radially to the shaft 14, and the spacer insures the axial position of the gears with respect to one another on the shaft. Similarly to the ends 26 and 28 of the spacer 20, the ends 26' and 28' of the spacer 30 are squared for establishing a radially uniform support surface for contact with each of the gears.

In this case, however, the contact is not resilient as there is no need for preloading of the sides of the gears 32 and 34.

It will be appreciated by those skilled in the art that the countershaft 14 is a rotatable shaft, and as a result will rotate the spacer member 30. The member 30 is fully exposed to the splash and spray oil environment within the transmission body. Those skilled in the art will appreciate the fact that the helicoidal body portion 24' of the spacer 30 will tend to cause oil slung away from the spacer to have a slight axial, as opposed to fully radial, component. As a result, the closed coil spacer 30 may be employed to enhance the oil dispersion within the transmission body by distributing the oil in a more desirable spray pattern.

Again, in a preferred form, the spacer 30 is made of non-heat treated high carbon spring steel.

Although only two preferred embodiments of the spacer of the present invention have been described and shown herein, there are many variations of the invention which will fall within the scope of the following apended claims.

Claims (14)

1. A spacer disposed for circumferentially encasing a transmission gear shaft, said spacer comprising a helicoidal body portion defining an open coil, said body portion having ends resiliently disposed between a pair of bearings, said body portion facilitating an axial flow of splash and spray oil along said shaft between said bearings.

2. The spacer of Claim 1 wherein said ends are squared for establishing a radially uniform support surface for contact with each of said bearings.

3. The spacer of Claim 2 wherein said shaft is a non-rotatable reverse idler shaft, and wherein the shaft contains a rotatable gear supported radially outwardly of said spacer, whereby said splash and spray oil is urged through the bearings disposed either side of said spacer by said helicoidal body portion of said spacer.

4. The spacer of Claim 3 wherein said gear shaft has an outside diameter less than the inside diameter of the spacer.

5. The spacer of Claim 4 wherein said helicoidai body portion is a non-heat treated, high carbon spring steel.

6. The spacer of Claim 5 wherein said squared ends are disposed for making resilient contact with needle bearings.

7. A spacer disposed for circumferentially encasing a transmission gear shaft, said spacer comprising a helicoidal body portion defining a closed coil, said body portion having ends tightly disposed between a pair of gears, said spacer disposed for axially locating said gears with respect to one another on said shaft.

8. The spacer of Claim 7 wherein said ends are squared for establishing a radially uniform support surface for contact with each of said gears.

9. The spacer of Claim 8 wherein said shaft is a rotatable transmission countershaft, and wherein said pairs of gears are radially keyed to said shaft.

10. The spacer of Claim 9 wherein said shaft has an outside diameter less than the inside diameter of the spacer.

11. The spacer of Claim 10 wherein said helicoidal body is of a non-heat treated high carbon spring steel.

12. In a transmission including a housing containing a plurality of parallel shafts, gears positioned on said shafts and rotatable within said housing, a first of said shafts being rotatable within said housing, and containing a pair of gears radially fixed thereto, and including a first spacer member circumferentially encasing said shaft and disposed intermediately of said gears for maintaining said gears in an axially spaced relationship; a second of said shafts being fixed within said housing and containing a pair of bearings for supporting a least one rotatable gear thereon, said second shaft containing a second spacer member circumferentially encasing said second shaft and positioned axially intermediately of said bearings for maintaining said bearings in an axially spaced relationship; an improvement comprising said first and second spacer members both defining helicoidal body portions.

13. A spacer substantially as described herein with reference to, and as shown in, the accompanying drawings.

14. A transmission including a spacer in accordance with any one of claims 1 to 11 or 13.