Claims:We claim:

1. A split-type transmission housing assembly for two-wheel drive vehicles and having enhanced bearing lubrication and servicing mechanism, said transmission housing comprises:

• a split-type transmission housing configured with a front housing (1) and a rear housing (3A) integrally accommodating the assemblies of an input shaft (9), an output shaft (19) therein;

• said input shaft (9) connected to and in alignment with output shaft (19) within said transmission housing, and said output shaft (19) being supported between a respective front and rear taper roller bearings (59, 60) thereof, which are mounted inside said transmission housing;

• an adapter plate assembly (4) bolted at the rear-end of rear housing (3A) for supporting the rear end of output shaft (19);

wherein said adapter plate assembly (4) is configured as a separate assembly bolted at the rear end of said rear housing (3A) in a detachable manner, and comprises a mechanism for facilitating an enhanced lubrication and servicing of taper roller bearing (60) of output shaft.

2. The split-type transmission housing assembly as claimed in claim 1, wherein said transmission housing assembly comprises:

• said front housing (1) accommodating and supporting the assemblies of input shaft (9) and output shaft (19) therein;

• said rear housing (3A) bolted on said front housing (1) to make an integral transmission housing for accommodating and supporting the assemblies of input shaft (9) and output shaft (19) therein;

• said output shaft (19) connected to input shaft (9) and supported on a needle roller bearing (70) mounted at the rear end of input shaft (9); output shaft (19); and

• said output shaft (19) also supported between two taper roller bearings (59, 60) mounted within rear housing (3A) and disposed adjacent the front end of output shaft (19) and the rear end thereof supported within adapter plate assembly (4) bolted at the rear end of rear housing (3A);

3. The split-type transmission housing assembly as claimed in claim 2, wherein said adapter plate assembly (4) mounted in a sealing manner inside the rear end of rear housing (3A) to support the rear end of output shaft (19) in a sealing manner.

4. The split-type transmission housing assembly as claimed in claim 3, said adapter plate assembly (4) comprises:

• a cylindrical adapter plate (4A) open at both ends thereof for insertion of output shaft (19) therethrough, and having said plurality of stepped outer and inner diameters and a mounting flange for bolting thereon on the rear end of said rear housing (3A);

• a cylindrical bush (4B) supported on and contacting said output shaft (19) and disposed within the front (input shaft side) end of said adapter plate (4A);

• a circlip (4C) placed in an annular groove on the internal diameter of said adapter plate (4A) and configured adjacent the rear end thereof, for locking of said bush (4B) therein;

• a hollow cylindrical dust cover (99) fitted at the rear end of adapter plate assembly (4) with the rear end of output shaft (19) passing therethrough; and

• an oil-seal (89) fitted at the rear end of adapter plate (4A) and disposed adjacent said dust cover (99) for sealing of adapter plate assembly (4) at the rear end thereof;

wherein said bearing lubrication and servicing mechanism comprises an oil supply passage (115) configured on said adapter plate (4A) for supplying oil received from the front (input shaft side) end thereof via an oil-channel (117) to said bush (4B) for enhanced lubrication thereof.

5. The split-type transmission housing assembly as claimed in claim 4, wherein said adapter plate (4A) comprises an outer annular groove for placing an O-ring (85) for mounting of said adapter plate assembly (4) in a sealing manner inside the rear end of said rear housing (3A).

6. The split-type transmission housing assembly as claimed in claim 5, wherein said adapter plate (4A) comprises a plurality of stepped outer and inner diameters for reducing weight thereof and for facilitating the assembly thereof inside the rear end of said rear housing (3A) and for the assembly of an oil-seal (80) on said output shaft (19) to be covered with a dust cover (99) for protection thereof from ingress of dust into said integral housing.

7. The split-type transmission housing assembly as claimed in claim 4, wherein said bearing lubrication and servicing mechanism comprises a longitudinal oil passage (115) configured on the outer surface of said adapter plate (4A) and extending from the front (input shaft) end thereof to receive lubricating oil from the oil gallery at the front end of said adapter plate (4A) and to be supplied via said oil-channel (117) radially configured and connected to said oil passage (115) at one end thereof and connected to and aligned with a through hole (118) at the other end thereof, which is radially disposed adjacent the center of bush (4B) for enhanced lubrication of the contact region thereof with the output shaft (19).

8. The split-type transmission housing assembly as claimed in claim 5, wherein said adapter plate (4A) comprises an oil drain point (116) to drain oil from said oil seal (89) via a longitudinal oil drain channel (120) disposed diametrically opposed to said oil passage (115).

9. The split-type transmission housing assembly as claimed in claim 5, wherein said adapter plate (4A) comprises another radial through hole (119) radially disposed diametrically opposite to said though hole (118) and connected to said oil-drain channel (120) for a fluid communication with the oil gallery of said integrated transmission housing.

10. The split-type transmission housing assembly as claimed in claim 6, wherein said adapter plate (4A) comprises at least two webs (121; 122) radially extending outwards from the corresponding stepped outer diameters of adapter plate (4A) and to be supported on the respective inner portions of said rear housing (3A) and having an outer diameter corresponding to a respective internal diameters of said rear housing supporting said webs (121; 122) thereon, wherein at least one of said webs (121; 122) is disposed substantially adjacent the center of said bush (4B) for supporting said adapter plate assembly (4) inside said rear housing (3A).

11. The split-type transmission housing assembly as claimed in claim 10, wherein said adapter plate (4A) comprises a flange radially extending outwards from the rear end of one of said web (122) disposed adjacent the rear end of said adapter plate (4A) to facilitate the mounding of said adapter plate assembly (4) on the rear end of said rear housing (3A).

12. The split-type transmission housing assembly as claimed in claim 11, wherein the corner between said web (122) and said mounting flange (123) is configured with an outer annular groove (124) for placing an O-ring (85) therein before mounting of said adapter plater assembly (4) at the rear end of said rear housing (3A) in a sealing manner.

Digitally Signed.

Dated this 01st day of September 2020.

(SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA-2043. , Description:FIELD OF INVENTION

The present invention relates to an improved transmission housing for two-wheel drive vehicles. In particular, the present invention relates to a compact and light-weight transmission housing with improved lubrication and bearing servicing mechanism for two-wheel drive vehicles. More particularly, the present invention relates to a split-type transmission housing with a separate adaptor assembly for easy lubrication and bearing servicing of the reduction output shaft bearing in two-wheel drive vehicles.

BACKGROUND OF THE INVENTION

The transmission housing for two-wheel drive vehicles is connected to propeller shaft to transmit power to the driving wheels of such vehicles. Some of the existing transmission housings are split-type transmission housing in which the housing is divided into three or more parts and thus requires an excellent joint between them, which may be prone to oil leakages therefrom. Such transmission housing may have, for example, a large diameter propeller shaft connected to the reduction output shaft, which make the transmission housing bulky, heavier and difficult to package in the vehicle. Moreover, it is difficult to provide lubrication of the bearings and removal and/or replacement of the taper roller bearings supporting the output shafts therein, which makes the serviceability thereof complicated and time-consuming. Because the whole housing needs to be dismantled for servicing of bearings requiring removal and/or repair thereof. This also necessitates removal of the bush supporting the output shaft.

Therefore, there is an existing need for providing a split-type transmission housing, which is compact, low-weight, has fewer joint faces and which also facilitates the lubrication and servicing of the output shaft thrust roller bearing and bush, particularly for removal/replacement thereof.
OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a compact split-type transmission housing for two-wheel drive vehicles, and having an enhanced bearing lubrication mechanism.

Another object of the present invention is to provide a light-weight split-type transmission housing for two-wheel drive vehicles, and having an improved servicing mechanism.

Still another object of the present invention is to provide a split-type transmission housing for two-wheel drive vehicles, and having an improved lubrication and servicing mechanism to facilitate easy removal/replacement of thrust roller bearing and bushes therefrom, whenever required.

Yet another object of the present invention is to provide a split-type transmission housing for two-wheel drive vehicles, which also saves material by compacter dimensions thereof.

Yet another object of the present invention is to provide a split-type transmission housing for two-wheel drive vehicles, which also saves time for assembly/disassembly of the output shaft bearing due to separable configuration of the lubrication and servicing mechanism thereof.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.
DESCRIPTION OF THE INVENTION

In accordance with the present invention, a split-type transmission housing assembly for a two-wheel drive vehicle is configured as an integrally formed of a front and rear housing each, which combinedly accommodate the input shaft and output shaft with a smaller diameter than the conventional output shaft. A smaller diameter output shaft also reduces the diameter of the propeller shaft to be connected thereto, and thus makes the transmission housing assembly compact and low-weight.

An improved lubrication mechanism is also configured in an adapter plate assembly fitted on the rear-end of the rear housing of this split-type transmission housing assembly. This adapter plate assembly includes a substantially cylindrical adapter plate to support the output shaft connected to the propeller shaft, and the front end thereof is linearly aligned with the input shaft to transmit torque received therefrom to the propeller shaft. Needle bearing are provided between the front end of the output shaft and the input shaft connected thereto. A pair of thrust roller bearing mounted inside the rear housing and adjacent the front end of the output shaft for rotatably supporting the same.

The unique feature of the present invention is the removeable adapter plate assembly, which not only facilitates the servicing including repair and/or replacement of the rear-side thrust roller bearing but also ensure an enhanced lubrication of thereof and the bush mounted within the adapter plate assembly for supporting the rear end of the output shaft therein.

Therefore, this configuration of adapter plate assembly separately bolted to the rear end of the rear housing facilitates an easy removal of the rear-side taper roller bearing, whenever required. This separate adapter plate assembly also houses a bush and an oil seal for better lubrication of the output shaft. This integral housing fitted with the adapter plate assembly for connecting the output shaft to the propeller shaft also eliminates one additional joint face, present in the conventional split-type transmission housing discussed above.

Moreover, the adapter plate assembly also includes an enhanced lubrication mechanism for an easy passage of the lubricating oil via an oil entry passage provided from the input side (front) face of the adapter plate and having through holes on the circumferential surface thereof for supplying this lubricating oil via an oil channel to the oil gallery and between the bush and output shaft supported thereon. The adapter plate also includes an oil drain channel to oil communication with the oil gallery in the transmission housing.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a split-type transmission housing assembly for two-wheel drive vehicles and having enhanced bearing lubrication and servicing mechanism, said transmission housing comprises:

• a split-type transmission housing configured with a front housing and a rear housing integrally accommodating the assemblies of an input shaft, an output shaft therein;

• said input shaft connected to and in alignment with output shaft within the transmission housing, and the output shaft being supported between a respective front and rear taper roller bearings thereof, which are mounted inside the transmission housing;

• an adapter plate assembly bolted at the rear-end of rear housing for supporting the rear end of output shaft;

wherein the adapter plate assembly is configured as a separate assembly bolted at the rear end of the rear housing in a detachable manner, and comprises a mechanism for facilitating an enhanced lubrication and servicing of taper roller bearing of output shaft.

Typically, the transmission housing assembly comprises:

• the front housing accommodating and supporting the assemblies of input shaft and output shaft therein;

• the rear housing bolted on the front housing to make an integral transmission housing for accommodating and supporting the assemblies of input shaft and output shaft therein;

• the output shaft connected to input shaft and supported on a needle roller bearing mounted at the rear end of input shaft; output shaft; and

• the output shaft also supported between two taper roller bearings mounted within rear housing and disposed adjacent the front end of output shaft and the rear end thereof supported within adapter plate assembly bolted at the rear end of rear housing;

Typically, the adapter plate assembly mounted in a sealing manner inside the rear end of rear housing to support the rear end of output shaft in a sealing manner.

Typically, the adapter plate assembly comprises:

• a cylindrical adapter plate open at both ends thereof for insertion of output shaft therethrough, and having the plurality of stepped outer and inner diameters and a mounting flange for bolting thereon on the rear end of the rear housing;

• a cylindrical bush supported on and contacting the output shaft and disposed within the front (input shaft side) end of the adapter plate;
• a circlip placed in an annular groove on the internal diameter of the adapter plate and configured adjacent the rear end thereof, for locking of the bush therein;

• a hollow cylindrical dust cover fitted at the rear end of adapter plate assembly with the rear end of output shaft passing therethrough; and

• an oil-seal fitted at the rear end of adapter plate and disposed adjacent the dust cover for sealing of adapter plate assembly at the rear end thereof;

wherein the bearing lubrication and servicing mechanism comprises an oil supply passage configured on the adapter plate for supplying oil received from the front (input shaft side) end thereof via an oil-channel to the bush for enhanced lubrication thereof.

Typically, the adapter plate comprises an outer annular groove for placing an O-ring for mounting of the adapter plate assembly in a sealing manner inside the rear end of the rear housing.

Typically, the adapter plate comprises a plurality of stepped outer and inner diameters for reducing weight thereof and for facilitating the assembly thereof inside the rear end of the rear housing and for the assembly of an oil-seal on the output shaft to be covered with a dust cover for protection thereof from ingress of dust into the integral housing.

Typically, the bearing lubrication and servicing mechanism comprises a longitudinal oil passage configured on the outer surface of the adapter plate and extending from the front (input shaft) end thereof to receive lubricating oil from the oil gallery at the front end of the adapter plate and to be supplied via the oil-channel radially configured and connected to the oil passage at one end thereof and connected to and aligned with a through hole at the other end thereof, which is radially disposed adjacent the center of bush for enhanced lubrication of the contact region thereof with the output shaft.

Typically, the adapter plate comprises an oil drain point to drain oil from the oil seal via a longitudinal oil drain channel disposed diametrically opposed to the oil passage.

Typically, the adapter plate comprises another radial through hole radially disposed diametrically opposite to the though hole and connected to the oil-drain channel for a fluid communication with the oil gallery of the integrated transmission housing.

Typically, the adapter plate comprises at least two webs radially extending outwards from the corresponding stepped outer diameters of adapter plate and to be supported on the respective inner portions of the rear housing and having an outer diameter corresponding to a respective internal diameters of the rear housing supporting the webs thereon, wherein at least one of the webs is disposed substantially adjacent the center of the bush for supporting the adapter plate assembly inside the rear housing.

Typically, the adapter plate comprises a flange radially extending outwards from the rear end of one of the web disposed adjacent the rear end of the adapter plate to facilitate the mounding of the adapter plate assembly on the rear end of the rear housing.

Typically, the corner between the web and the mounting flange is configured with an outer annular groove for placing an O-ring therein before mounting of the adapter plater assembly at the rear end of the rear housing in a sealing manner.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described in the following with reference to the accompanying drawings.

Figure 1a shows a 4W-drive vehicle equipped with a conventional transmission housing (e.g. Fortuner) having 3 separate portions for accommodating (not visible here) the input shaft assembly, bearing assembly, and output shaft and pivot assembly/gear-shifter connected by joints therebetween.

Figure 1b shows an enlarged view of the transmission housing of Figure 1a, after opening one of the joints thereof to show the pivot assembly connected to the output shaft.

Figure 2 shows a transmission housing of an existing manual transmission of a two-wheel drive vehicle manufactured by the applicant and which has thrust roller bearings TRB supporting the output shaft OPS pressed from front side of the transmission housing.

Figure 3a shows an external side view of a compact split-type transmission housing assembly for two-wheel drive vehicles having integrally connected front housing an input shaft assembly connected to an output shaft assembly supported in a rear housing having an improved bearing lubrication and servicing mechanism configured in accordance with the present invention.

Figure 3b shows an enlarged partial perspective view from the right-side of the rear housing of Figure 3a, and configured with an improved bearing lubrication and servicing mechanism as an adapter plate assembly.

Figure 3c shows a cross-sectional view of the adapter plate assembly of Figure 3b with different components thereof, before fitting thereof within the rear housing as shown in Figure 3a.

Figure 4a shows a cross-sectional view of the adapter plate assembly fitted mounted at the rear end of the transmission housing, as shown in Figure 3a.

Figure 4b shows an enlarged cross-sectional view of the rear housing of assembled with the adapter plate assembly, as shown in Figure 4a, to highlight the features of the enhanced lubricating and servicing mechanism configured in accordance with the present invention.

Figure 4c shows a further enlarged partial perspective cross-sectional view of the adapter plate, as seen from the front (input-shaft) end of the enhanced lubricating and servicing mechanism shown in Figure 4b.

Figure 4d shows the adapter plate assembly visible from the rear end of the rear housing of Figure 4a.

Figure 4e shows a sectional view across section line 1-1 of the rear housing assembly shown in Figure 4b.

Figure 4f shows a sectional view across section line 2-2 of the rear housing assembly shown in Figure 4b.

Figure 5a shows a cross-sectional view of the front housing of the split transmission housing configured according to the present invention and shown in Figure 3a.

Figure 5b shows a cross-sectional view of the rear housing of the split transmission housing of the present invention and shown in Figure 3a.

Figure 5c shows a partial cross-sectional detailed view of the rear housing assembly fitted with different components therein, including the adapter plate assembly (Figure 4a) marked within a dashed ellipse therein.

Figure 6a shows a perspective view of the adapter plate of Fig. 3c, as seen from the rear end thereof, without dust cover fitted thereon.

Figure 6b shows a perspective view of the adapter plate of Fig. 3c, as seen from front end thereof, without dust cover fitted thereon.

Figure 6c shows a perspective cross-sectional view of the adapter plate assembly of Figure 3c, and sectioned in the center along a horizontal plane thereof.

Figure 6d shows a partial perspective cross-sectional view of the rear-end of the rear housing assembly of Figure 4a.

Figures 7a-7d show exploded cross-sectional views of the different components of the adapter plate assembly shown in Figure 3c.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, an improved lubrication mechanism for a split-type transmission housing for two-wheel drive vehicles and configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention.

Figure 1a shows a 4W-drive vehicle equipped with a conventional transmission housing (e.g. Fortuner) having 3 separate portions connected by joints therebetween, i.e. H1 for accommodating (not visible here) the input shaft assembly, H2 for the bearing assembly, and H3 for the output shaft and gear-shifter/pivot assembly. However, it includes multiple joint faces J1, J2, J3, which increases the manufacturing, machining and assembly costs and also complicate the arrangement of lubrication mechanism thereof.

Figure 1b shows an enlarged view of the transmission housing of Figure 1a, and with the portion H3 after opening the joint J3 thereof to show the gear-shifter/pivot assembly PA connected to the output shaft (not visible here).

Figure 2 shows a transmission housing of an existing 6MT manual transmission H of two-wheel drive vehicle manufactured by the applicant, and which has thrust roller bearing TRB supporting the output shaft OPS pressed in a direction D from the front side of transmission housing H.

Figure 3a shows an external side view of a compact split-type transmission housing assembly for two-wheel drive vehicles, and having integral housing with an assembly of input shaft 9 connected to an output shaft 19 supported in a rear housing 3A having an improved bearing lubrication and servicing mechanism configured in accordance with the present invention
Figure 3b shows an enlarged partial perspective view from the right-side of rear housing 3A of Figure 3a, and configured with an improved bearing lubrication and servicing mechanism as an adapter plate assembly 4 including an adapter plate 4A fitted with a dust cover 99 and supporting output shaft 19, and this adapter plate assembly 4 is fitted on rear housing 3A.

Figure 3c shows a cross-sectional view of the adapter plate assembly 4 of Figure 3b and having an adapter plate 4A with a bush 4B mounted therein and locked by a circlip 4C placed in a groove provided therein, dust cover 99 ted within rear end of adapter plate 4A and an O-ring 85 placed in another circumferential groove provided on the outer stepped surface thereof, and for mounting this adapter plate assembly 4 inside the rear housing 3A in a leakproof manner.
Figure 4a shows a cross-sectional view of the adapter plate assembly 4 mounted inside the rear end of rear housing 3A of split-type transmission housing assembly of Figure 3a, which in turn is bolted on front housing 1. The adapter plate assembly 4 supports the output shaft 19 at the rear end thereof and the front end of output shaft 19 is supported on two taper roller bearings 59, 60. The first taper roller bearing 59 fitted from inside the front housing 1 and the second taper roller bearing 60 fitted from the rear side of the rear housing 3A and locked in place by a lock nut 79. The output shaft 19 is connected to the input shaft 9 with a needle bearing 70 disposed therebetween. The rear end of the output shaft 19 has splines for coupling thereof with the propeller shaft of the vehicle. A dust cover 99 is fitted inside the rear end of rear housing 3A. An oil seal 89 seals the gap between the output shaft 19 and an inner diameter of the adapter plate 4A. The oil seal 89 is disposed between the dust cover 99 and a stepped inner diameter of the adapter plate 4A. During transit of the integral transmission housing assembly, a protective cap is fitted in the gap between the splines of output shaft 19 and the inside diameter of the oil seal 89. Since thrust roller bearing 60 is pressed from the rear side of rear housing 3A, the removal of adapter plate assembly with dust cover 99 from the rear housing facilitates in easily removing and/or replacing and servicing this bearing 69. It is important to note that the transmission housing assembly configured according to the present invention involves at least one joint face less than three joint faces J1, J2, J3 shown in the conventional transmission housing of Figure 1a. Moreover, the outer diameter of the output shaft 19 is substantially less than output shaft of the conventional transmission housing of Figure 1a, which also reduces the diameter of the propeller shaft, which saves material cost and thereby the cost as well as makes the transmission housing compacter. To facilitate easy removal of the taper roller bearing 60 and output shaft 19 whenever required, the adapter plate assembly 4 is made as a separate unit housing the bush 4B locked therein by circlip 4C and fitted with oil-seal 89, which can be easily removed as a whole from unfastening the same from the rear housing 3A. Thus, after removal of the whole adapter plate assembly 4, taper roller bearing 60 can be easily removed for repair and/or replacement and servicing thereof. Most importantly, the adapter plate 4A includes a bearing lubrication and servicing mechanism configured as a longitudinal oil passage 115, through which lubrication oil received from the oil gallery can be supplied via a longitudinal passage 115 from input shaft side into an oil channel 117 radially connected at the other end thereof and aligned with a through hole 118 in bush 4B to lubricate the contact region between bush 4B and output shaft 19 for enhanced lubrication thereof. The adapter plate includes another longitudinal drain 116 connected to a through hole 119, preferably disposed opposite the through hole 118, for draining of lubricating oil from oil seal 89 into oil gallery.

Figure 4b shows an enlarged cross-sectional view of the rear housing 3A of assembled with the adapter plate assembly 4 as in Figure 4a. This figure shows the detailed arrangement of the enhanced bearing lubricating and servicing mechanism for the thrust roller bearing 60 configured in accordance with the present invention. The longitudinal passage 115 is shown connected to oil channel 117 to supply oil via through hole 118 in bush 4B aligned thereto. The taper roller bearing (TRB) 60 mounted inside the rear housing 3A rotatably supports the output shaft 19 and is locked thereon by a lock-nut 79. The oil seal 89 is disposed between dust cover 99 and bush 4B fitted inside the adapter plate 4A. An O-ring 85 is placed over the corner of the adapter plate 4A with the flange thereof before mounting it on the rear end of rear housing 3A. Two section lines 1-1 and 2-2 are also marked here for elaborating the details thereof described below.

Figure 4c shows a further enlarged partial perspective cross-sectional view of the adapter plate 4A, as seen from the front (input-shaft) end of the enhanced lubricating and servicing mechanism of Figure 4b. It clearly indicates the longitudinal passage 115 for lubricating oil to enter into the adapter plate and leading to a radial oil channel 117 for supply thereof via through hole 118 in bush 4B to lubricate the contact region thereof with the output shaft 19 for enhanced lubrication thereof.

Figure 4d shows the adapter plate assembly 4 from the rear end of rear housing 3A and indicating the drain point 116 for draining of from oil seal 89 into the oil gallery of the integral housing assembly.

Figure 4e shows a sectional view across section line 1-1 of the rear housing 3A assembly of Figure 4b, and showing the adapter plate assembly with an entry for longitudinal passage 115, drain point 116 (for oil from oil seal 89) and through hole 118 connected thereto for draining oil into the oil gallery.

Figure 4f shows a sectional view across section line 2-2 of the rear housing 3A assembly of Figure 4b, and showing the radial channel 117 connected via through hole 118 in bush 4B for supplying oil for lubrication of the contact region thereof with the output shaft 19 for enhanced lubrication thereof.

Figure 5a shows a cross-sectional view of the front housing 1 of the profiled split transmission housing (1, 3A) configured in accordance with the present invention.

Figure 5b shows a cross-sectional view of the rear housing 3A of the transmission housing to be integrally mounted on the front housing 1 thereof configured in accordance with the present invention.

Figure 5c shows a partial cross-sectional detailed view of the rear housing 3A fitted with different components therein, including the adapter plate assembly 4 (Figure 4a) configured in accordance with the present invention and shown within dashed ellipse marked therein. The output shaft 19 is shown aligned with the input shaft on LHS thereof and with the adapter plate assembly 4 aligned on RHS thereof. Similar to Figure 4a, the adapter plate assembly 4 includes adapter plate 4A, bush 4B and locked by circlip 4C thereon, and then fitted on the rear housing 3A after placing O-ring 85 in the corner of the flange mounted on the rear housing 3A and an oil seal 89 is also placed between the adapter plate 4A and the dust cover 99 before fitting it therein.

Figure 6a shows a perspective view of the adapter plate 4A of Fig.3c, however without dust cover 99 fitted thereon, when seen from the rear end thereof. It clearly shows the oil drain channel 120 opening at the drain point 116 and the longitudinal oil passage 115, both of which are visible in Figure 4e.

Figure 6b shows a perspective view of the adapter plate 4A of Fig.3c, however without dust cover 99 fitted thereon, when seen from the front end thereof. It also shows the oil drain channel 120 opening at the drain point 116 and the longitudinal passage 115 leading to the oil channel 117, both of which are visible in Figure 4e.

Figure 6c shows a perspective cross-sectional view of the adapter plate assembly 4 of Figure 3c, and sectioned at the center along a horizontal plane thereof. The adapter plate assembly 4 includes adapter plate 4A, bush 4B locked in place by circlip 4C in a circumferential groove provided therein, an oil seal disposed between the dust cover 99 and inner side of the mounting flange of adapter plate 4A and. As in Figure 4c, the lubrication mechanism configured in accordance with the present invention includes a longitudinal passage/channel 115 for lubricating oil to enter into adapter plate 4A from front (input shaft side) end and leading to a radial oil channel 117 for supply thereof via through hole 118 in bush 4B to lubricate the contact region thereof with the output shaft 19 for enhanced lubrication thereof. Therefore, this adapter assembly functions as a separate housing for bush 4B fitted within adapter plate 4A and oil seal 89 disposed between dust cover 89 and inner side of the mounting flange of the adapter plate 4A. This assembly 4 is easily removeable for facilitating the removal of bearing 60 and/or bush 4B for repair and/or replacement, whenever required.

Figure 6d shows a partial perspective cross-sectional view of the rear-end of the assembly of rear housing 3A of Figure 4a, and fitted on the output shaft 19 along with the adapter plate assembly 4 fitted with oil seal 89 and dust cover 99, as discussed in Figure 6c above.

Figure 7a shows a cross-sectional view of adapter plate 4A discussed above.

Figure 7b shows a cross-sectional view of dust cover 99 discussed above.

Figure 7c shows a cross-sectional view of circlip 4C discussed above.

Figure 7d shows a cross-sectional view of O-ring 85 discussed above.

Figure 7e shows a cross-sectional view of bush 4B discussed above.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The improved arrangement of an improved lubrication mechanism for a split-type transmission housing for two-wheel drive vehicles and configured in accordance with the present invention offers the following advantages:

• Reduces at least one joint face and therefor oil-seal required.

• Reduced joint-face also makes the transmission housing compacter.

• Separate housing for bush and oil seal facilitates assembly and dismantling of the transmission housing.

• Material saving due to reduced propeller shaft diameter due to smaller output shaft diameter.
• Facilitates in removal/replacement and enhanced lubrication of output shaft taper roller bearing.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

Certain terminology is used in the following description for convenience only and is not limiting. The description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are to be considered part of the entire written description.

In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom” as well as derivatives thereof (e.g. “horizontally”, “inwardly”, “outwardly”; “downwardly”, “upwardly” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion.

Similarly, the words "right", "left", "lower" and "upper" designate directions in the drawings to which reference is made. The words "inwardly" or "distally" and "outwardly" or "proximally" refer to directions toward and away from, respectively, the geometric center of the bone anchor and related parts thereof.

Further, the words, "anterior", "posterior", "superior," "inferior" and related words and/or phrases designate preferred positions and orientations in the body to which reference is made and are not meant to be limiting. The terminology includes the above-listed words, derivatives thereof and words of similar import.

LIST OF REFERENCE NUMERALS
Conventional transmission housing:
H1 First portion H2 Second portion H3 Third portion
J1 First joint face J2 Second joint face J3 Third joint face
PA Pivot assembly

H Applicant’s existing manual transmission housing for 2W-drive vehicle
OPS Output shaft for 6MT TRB Thrust roller bearing
NRB Needle roller bearing

Split-type Transmission housing of the present invention:
1 Front housing
3A Rear housing
4 Adapter plate assembly
4A Adapter plate
4B Bush
4C Circlip
19 Output shaft
59, 60 Taper roller bearings
70 Needle bearing
79 Lock-nut
85, 89 O-ring and Oil-seal
99 Dust cover
111 Cap for oil-seal
115, 116 Oil-entry passage and Oil-drain point
117 Radial oil-channel
118 Radial through hole in bush
119 Radial through hole in adapter plate
120 Oil drain channel from oil-seal
121, 122 Web on the external surface of adapter plate
123 Mounting flange of adapter plate
124 Groove for placing oil ring on adapter plate.