ZA200005008B - Vehicle Transmissions. - Google Patents

Description

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N ) WO 99/48719 : PCT/IB99/00496 . -1 - :

VEHICLE MOUNTING OF TRANSMISSION PROPSHAFT

This invention relates to vehicle transmissions especially for busses.

The invention is concerned with such transmissions incorporating a plurality of prop shafts and bearings by which they are carried by the vehicle chassis. In particular the invention is concerned with a transmission for a vehicle having a chassis, a drive transmission and a differential gear connected to the driving wheel; the transmission being of the kind comprising a first prop shaft that in use is connected to the drive transmission, a centre prop shaft, and a third prop shaft that in use is connected to the differential gear, each of the prop shafts incorporating a main tubular shaft, a universal joint at one end of the shaft, a flanged yoke forming part of the universal joint, and a companion flange at the other end. Such a transmission is hereinafter called a "trans- mission of the kind set forth". Co

In a known transmission of the kind set forth a bearing is provided for the first and second prop shafts. This bearing

B incorporates a housing which is suspended from the chassis and a rolling bearing (which in this case is a ball bearing) having

Co its inner race mounted on a shaft forming part of or being attached to the tubular shaft near its end which is remote from the universal joint. The bearing is packed with grease for lubrication purposes. To enable the bearing to accommodate 2% misalignments or angular deflections of the prop shaft, the

CONFIRMATION COPY rolling bearing comprises a self aligning ball bearing arrange- ment.

Although such a known transmission is generally satisfactory in operation, in practice there are many problems with such transmissions. These problems arise for a number of reasons. First, it has been found that if the self aligning bearing is unable to accommodate the misalignment of the prop shaft, the bearing tends to heat substantially causing the grease to become liquid with consequent inability to provide adequate lubrication which causes failure. Indeed such mis- alignment causes failure for other reasons. Further we have found that if such failure takes place the effect is often that all bearings break away from the chassis causing all three prop shafts to be damaged, if not destroyed.

According to one aspect of the invention there is provided a bearing for use in a prop shaft transmission of the kind set forth, the bearing comprising a housing, a rolling bearing within the housing, a support device whereby the housing may be carried by the chassis, a main shaft on which the inner race of the rolling bearing is mounted and flanges carried at each end of the main shaft. The housing is preferably designed to contain liquid lubricant and seals are provided on the housing to seal against the main shaft. Preferably at each end of the housing there are provided two seals, one to retain the lubricant within the housing and the other to prevent the ingress of water and detritus into the housing.

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Y ] WO 99/48719 PCT/IB99/00496

The bearing conveniently comprises two rolling bearings preferably spaced apart by a part of the housing. Each rolling bearing preferably is a single row deep groove ball bearing.

According to another aspect of the invention there is : 5 provided a prop shaft transmission of the kind set forth wherein there is provided a pair of bearings carried by the chassis and each incorporating a main bearing shaft passing 3 through the bearing and having flanges at each end, : : wherein the adjacent flanges of the bearings are connected ) -.10 respectively to the flanges at the end of the centre prop shaft : and ~ wherein the remote flanges of the bearings are connected respectively to one of the flanges of the first and third prop shafts respectively. : 3 15 Preferably the third prop shaft is a length compensating shaft as may be the first shaft.

An embodiment of the invention will now will be described with reference to the accompanying drawings.

Referring now to the drawings:-

Figure 1 is a diagrammatic view of the chassis of a bus

E embodying a prop shaft transmission of the invention,

Figure 2 is a side view of a prop shaft transmission of the invention,

Figure 3 is a longitudinal section through a bearing of the invention with one companion shaft omitted for clarity, : Figure 4 is a section on line 4 - 4 of Figure 3,

Figure 5 is an end view of the bearing of Figure 3,

S Figure 6 is a detail section through the seals forming part of the bearing of Figure 3,

Figure 7 is a longitudinal section through a length compensating prop shaft, and

Figure 8 is a perspective view of a carrier plate.

Referring now to Figure 1, there is shown the chassis of a bus. The chassis comprises a pair of longitudinal chassis ' members A joined at spaced locations by cross-members B. A prop shaft train or transmission 100 conveys the drive from a flange 101 on the power takeoff shaft 103 of the gear box of the engine 102 to a flange 106 on the input shaft of the differential 104 connected to the driving wheels (not shown) .

The transmission 100 comprises a first prop shaft 108 connected to the power take off shafc 103 from the engine 102, a centre prop shaft 110 and a third prop shaft 112 that is connected to the differential gear 104. The third prop shaft 112 is a length compensating shaft. It will be described with reference to

Figure 7. The centre and first prop shafts 108 and 110 are identical to the shaft 112 save that it is not a length compensating shaft.

The prop shafts are connected together by identical first and second bearings 114 and 116. The first bearing 114 will be described with reference to Figures 3 to 6.

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- w . WO 99/48719 PCT/IB99/00496

Reference is now made to Figure 7. The first prop shaft 112 comprises an elongated prop shaft tube 118 having proximal and distal universal joints 120 and 122 at each end.

The universal joint 122 incorporates a ycke {lange 124 which | is bolted to the transmission flange 106. The inboard yoke 126 is carried on a member incorporating the male spline 128 and a tubular dust cover 130 therefor. The female spline 132 receives the male spline 128. The distal end is received in to the end of the tube 118. When the male spline 128 is fully homed in the female spline 132, the proximal end of the cutside ) of the female spline 132 is received in a slightly enlarged mouth 134 of the dust cover 130. Thus- the overall length of the " prop shaft can be altered in a manner appreciated by those skilled in the art. : ; 15 The distal end of the first prop shaft 118 receives a : cylindrical carrier member 137 of the inboard yoke 138 of the distal universal joint 120. The yoke flange 140 of the universal joint 120 is bolted to the proximal flange 142 of the bearing 114.

Reference is now made to Figure 3. The first bearing 114 comprises a housing consisting of a substantially tubular body member 144 with closures 146 bolted on to each end. The body member 144 has enlarged end openings 148 separated by a central - land 150. Within each end opening 148 is received the outer race 152 of a deep groove, caged, ball bearing 154 (i.e. a rolling bearing). A nose 156 on each end closure 146 forces

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_g the race 152 against the land 150. Each end closure 146, which is mainly of generally frusto-conical shape, has an inward flange 158 to form an annular chamber 160.

A shaft 162 is journalled in the rolling bearings 154.

Outside each of the bearings 154, the shaft 152 has a reduced diameter portion 164 which leads to a threaded end part 166 of further reduced diameter. A companion flange 168 is mounted on each portion 164. It has a carrier boss including a support body 170 which is generally conical, leading to a cylindrical extension 172 that is stepped down at a shoulder 174 to an end section 176. The end section 176 fits through the centre of the closure flange 158 and butts against the inner race 178 of the adjacent bearing 154. The shoulder 174 is then closely spaced from the cutside of the closure flange 158.

The outside face 180 of the companion flange 168 has a central recess 182 with an enlarged mouth 184. A nut 18s, having an integral thick washer 188, is threaded on to the threaded end part 166 to hold the companion flange 168 in position as described.

The shaft 162 is connected to the companion flange 168 into the following manner. Five bores 190 (best shown in

Figure 5) are drilled into the support body 170 and the reduced diameter portion 164 so that there is a half bore in each. A steel dowel 192 is inserted into each bore 180. The dowels 192 transmit the torque from the shafts 162 to the companion

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ISA/EP w 4 WO 99/48719 PCT/1B99/00496 » - 7 flange 168 and vice versa. Four of the bores 190 are equi- } spaced and the fifth is closer to one adjacent bore than the other. Thus the companion flange can only be connected to the shaft 162 in the correct annular disposition.

The annular chamber 160 contains two metal reinforced bearings 194 and 196 (best shown in Figure 6) each of which has an inner nose 197 that bears on the end section 176 of the support body 170. The outside diameter of the end portion 198 of the end section 176 is of slightly greater diameter than the adjacent inner portion 200. ~~ A drain opening 202 is formed at the bottom end of the

Co chamber 204 within the housing 144. A £illing opening 206 leads into the chamber 204 somewhat above the centre line as shown in Figure 4. Conventional plugs 208 close off these openings.

A pressure relief valve 210 projects from the upper end of the chamber 204.

Two carrier tubes 210 are welded to the outside of the body 150. Each tube 210 carries a rubberised "Metallastic" sleeve 212 within which are three inner bushes 214, 216 and 218 which are spaced from each other. A supporting pin (not shown) : fits into the bushes 214, 216 and 218 projecting from the ends to be mounted in a pair of carrier plates 220. The plates 220 each comprise a flange 222 with a pair of elongated slots 224 whereby the carrier plate 220 can be bolted to the underside of cross-member B of the chassis. The slots 224 permit

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ISA/EP adjustment of the position of the carrier plate. Pairs of openings 226 are formed in the plate 220 to receive the supporting pins of the carrier tubes 210 at the desired height.

A vertical slot 228 is provided in one plate so that the filling opening 206 is accessible for maintenance purposes.

The chamber 204 is filled with liquid lubricant (oil).

Because the shoulder 174 is so close to the outside of the flange 158 the chance of water entering the bearing 114 is small. This is reduced still further by the outside bearing 194 and of the upward step to the end of portion 198.

The inner bearing 196 serves to retain the liquid lubricant in the chamber 208. An "O"-ring 230 between the body 144 and the end closures 146 also serves to prevent leakage of the lubricant.

A slot 232 is cut into the end of the threaded pcrtion 166. When the nut 186 is homed it is indented into to the slot 232 to lock the nut in pesition.

The transmission 100 is mounted as follows:- The bearings are attached to the carrier plates which are loosely bolted to the cross members B. The prop shaft 108 is connected to the power take off shaft 101 through the flange 103 and to the shaft into the bearing 116 through the flanges. The flanges 220 carrying the bearing 114 are now moved to locate the bearing accurately on the cross-member and then fixed on to the cross- member B. The centre prop shaft 110 is connected to the

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Yo shafts 162 of the bearings 114 and 116 in a similar manner and

Che bearing 116 is mounted to the vehicle chassis. The third prop shaft 114 is then connected between the shaft 162 of the bearing 116 and to the differential gear 104.

The provision of universal joints at the end of each prop shaft 108, 110 and 112 enables the transmission to compensate for any misalignment in mounting to the parts. The fact that the prop shaft 112 is a length compensating shaft enables the or : transmission to accommodate any rotational movement of the

B 10 differential gear 104 during start-up, acceleration and at the . deceleration of the vehicle. ’ I have found that the transmission described with reference to Figures 2 to 8 is significantly less prone to failure than conventional prop shaft transmissions even with . 15 minimal maintenance. Furthermore because the bearings are formed separately from the prop shafts should there be failure of a prop shaft this can be easily removed and replaced without : affecting the bearings. Conversely should a bearing fail this can be removed and replaced without having to replace the prop shafts. This considerably reduces the costs of maintenance and repair of the transmission.

In addition the connection between the housing shaft 162 and the companion flanges, i.e. the bores and dowels considerably reduces the cost of manufacture as compared to the costs where splines are used for this purpose.

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Because the bearings are separate from the prop shaft, the axial length of the latter is reduced ag compared to known systems with consequent reduction of whip of the prop shaft. By lubricating the rolling bearings with liquid lubricant, a much more positive control of the filling of the bearings can be exercised as compared to the use of a nipple and grease gun. In the unlikely event of failure of any part of the transmission, the failure will be localised and other parts will not be harmed.

In this specification the term "rolling bearing” is used.

This term distinguishes the particular apparatus from the assembly in which this apparatus is mounted. The term is intended to cover a bearing comprising an inner race, an outer ’ race and a ring of rolling members rolling between the races, such as a ball bearing, a roller bearing or the like.

The invention is not limited to the precise comstructional details hereinbefore described or as illustrated in the accompanying drawings. For example. splines may connect the housing shafts and the companion flanges. The shaft 164 may be connected to the companion flanges by means of splines. The third prop shaft 108 may also be a length compensating shaft.

The invention may also be applied to lorries and similar vehicles.

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Claims (13)

1. . - . EA ] WO 99/48719 PCT/IB99/00496

   CLAIMS 1 A prop shaft transmission for a vehicle having a chassis, a drive transmission and a differential gear connected to the driving wheel; the transmission comprising . 5 : a first prop shaft that in use is connected to the drive transmission, a centre prop shaft, and a third prop shaft that in use is connected to the differential gear,

   each of the prop shafts incorporating a main tubular shaft, a universal joint at one end of the shaft, a flanged yoke forming } part of the universal joint, and a companion flange at the oo other end: characterised in that there is provided a pair of bearings carried by the chassis, each incorporating a main shaft passing through the bearing and having flanges at each end,

   : in that the adjacent flanges of the bearings are connected respectively to the flanges at the end of the centre prop shaft and :

   in that the remote flanges of the bearings are connected respectively to one of the flanges of the first and third prop shafts respectively.
2. 2 A prop shaft transmission as claimed in claim 1 characteriged in that each prop shaft is provided with a universal joint at each end thereof.
3. 3 A transmission as claimed in claim 1 or claim 2 characterised in that the third prop shaft is a length compensating shaft.
4. 4 A transmission as claimed in claim 1, 2 or 3 characterised in that the first prop shaft is a length compensating shaft.
5. 5 A transmission as claimed in any one of the preceding claims characterised in that the bearing comprising a housing, a rolling bearing within the housing rotatably supporting the shaft, and a support device whereby the housing may be carried by the chassis.
6. 6 A transmission as claimed in any one of the preceding claims characterised in that the flange has a carrier boss which fits over and is attached to the shaft.
7. 7 A transmission as claimed in any one of the preceding claims characterised in that axial bores are drilled into the boss and shaft so that part of each bore is in one and part in the other and in that pins are provided in the bores to connect the boss to the shaft.
8. 8 A transmission as claimed in any one of the preceding claims characterised in that splines on the boss and shaft connect these parts together.

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9. 9 A transmission as claimed in any one of the preceding oo claims characterised in that the housing is designed to contain liquid lubricant and_in_that seals are provided on the housing to seal against the boss.

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10. 10 A transmission as claimed in claim 9 characterised in that at each end of the housing there are provided two seals, one to retain the lubricant within the housing and the other to

    = prevent the ingress of water and detritus into the housing.
11. 11 A transmission as claimed in claim 10 characteriged in that the diameter of the part of the boss against which the inner seal seals is slightly greater than the diameter of the oo part boss against which the outer seal seals.
12. 12 A transmission as claimed in any one of the preceding claims characterised in that bearing comprises two rolling bearings spaced apart by a part of the housing.
13. 13 A transmission as claimed in any one of the preceding claims characterised in that each rolling bearing is a single row deep groove ball bearing.

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