FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Improved (/earbox Oil Circulation System for Testing Gearbox on Test Bench in 'Back to Back' Mode


APPLICANTS
f ATA MOTORS LIMITED, an Indian company
paving its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Bhaskar B God bole, Yuvaraj M Jadhav, Sudhir M Sutar, M. W. Pawar, A. D. Bankar and S. Y. Bhoyar
All are Indian Nationals
of TATA MOTORS LIMITED,
■in Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF INVENTION
This invention is related to gear box of a vehicle and more particularly it relates to the gearbox with novel oil circulation system for testing gearbox on test bench in back to back mode.
BACKGROUND OF INVENTION
Generally, the gear box of an automobile is tested on test bench. This is done on test bench by connecting test gear box in between the main motor and generator motor. This methodology is more suitable for testing smaller test gear boxes. Because, for testing bigger gear box in this test setup, the output torque becomes very high for generators to absorb. For testing heavy gear box, a dynamometer capable of absorbing very high gear box output torque at very low speed will be required, which is very- difficult and cumbersome and becomes very costly test setup. Hence, a slave gearbox is used in between test gearbox and generator motor. The said test gear box rotates vehicle wise and the slave gear box rotates in anti vehicle wise direction. Now, there are two options available in this method for slave gear box. In the first option, the slave gear box can be of same design as that of the test gear box, but capable of rotating anti vehicle wise direction without any lubrication issues. Second option is to have changeable ratio gearbox as a slave gearbox. This becomes difficult to use since three to four restricted changeable gear ratios available in this gear box can not take care of the entire range of test gear box ratios and hence increases the dynamometer size, This also results into three to four times increase in dynamometer cost and reduces the flexibility of test rig since one such slave gear box can not be used for small (4 kg-m) as well as big (110 kg-m) test gear box because of ratio differences and inertia problems. Because of these constraints, new oil circulation system is developed inside the slave gear box for lubrication, so as the heavy test gear box can be tested for durability using slave gearbox of same design having new oil circulation system. The test was planned for 1300 hours and hence the solution was to be robust & reliable enough.

BRIEF DESCRIPTION OF INVENTION
In accordance with the present invention , gearbox oil circulation system for testing gearbox on test bench in back to back mode comprises; main motor unit, generator motor unit , test gear box connected with the said main motor, slave gear box with new oil circulation system connected with the said generator motor unit wherein, said oil circulation system comprises; inlet hole(16) for entry of oil in the pump assembly, pump assembly (3), oil path for circulating the oil(15), outlet for connecting the said oil path to oil gallery for distributing oil in the main shaft such that anti vehicle wise rotation of slave gear box shaft facilitates the oil circulation inside the gear box.
STATEMENT OF INVENTION
New oil circulation system of slave gear box comprises; inlet hole (16) for entry of oil in the pump assembly, rear side portion (10) of pump housing filled with metallic material, oil path (15) generated on the said rear side portion of pump housing for circulating the oil and thereafter, distributing oil in the main shaft such that anti vehicle wise rotation of slave gear box shaft facilitates the oil circulation inside the gear box.
The rear side portion of pump housing filled with filler materials. The oil path is generated on front side of pump housing configured in communication with the said oil gallery. The said oil pump housing comprises plurality of holes provided therein for mounting to the gear box.
Method of providing oil circulation system in slave gear box comprises:
• Selecting the pump housing from the existing system,
• Filling the filler materials at the rear side of said pump housing,
• Creating the new oil path on front side of said pump housing,
• Providing inlet on said pump housing,
• Providing outlet on said pump housing.

BRIEF DESCRIPTION OF DRAWINGS
Figure-01 shows the test setup for smaller gear box test,
Figure-02 shows the test setup for bigger gear box test in Back to Back Mode.
Figure-03 shows rear view of the prior art pump housing
Figure-04 shows front view of prior art pump housing.
Figure-05 shows rear view of pump housing in accorda^ce wjm tne present invention.
Figure-06 shows front view of oil circulation system in accordance with the present
invention.
Figure-07 shows rear view of fitment of new pump hou^w inside gearbox.
DETAILED DESCRIPTION OF INVENTION
Referring now to the drawings wherein the showings are for tne pUrp0se 0f illustrating a preferred embodiment of the invention onjy an(j noj for me purpose of limiting the same;
Now referring figure-01 to 07, In accordance with the present invention , gear box Oil circulation system for testing gear box on test bei^ in back t0 back mode; comprises; main motor unit, generator motor unit, test gear box connected with the said main motor, slave gear box with new oil circulatibn system connected with the said generator motor unit wherein said oil circulatjon svstem comprises* inlet hole(16) for entry of oil in the pump assembly, punip assembly (3), oil path for circulating the oil(15), outlet for connecting the saiy oil path to oil gallery for distributing oil in the main shaft such that anti vehicle vise rotation of slave gear box shaft facilitates the oil circulation inside the gear box.
The said oil circulation system is developed inside the pump housing of slave gearbox. New channel was created which will circulate oil when the oil pump is rotating in anti vehicle wise direction. This was achieved by:

• Filler material filled (10) on rear side of pump housing (1) as shown in figure-05
with shaded portion.
• Creation of new oil path (15) on front side of pump housing (1) as shown in
figure-06.
• Creation of new inlet (16) as shown in figure-06.
The new oil circulation system comprises; inlet hole for entry of oil in the pump assembly, oil path for circulating the oil, outlet for connecting the said oil path to oil gallery for distributing oil in the main shaft such that anti vehicle wise rotation of slave gear box shaft facilitates the oil circulation inside the gear box.
Now referring to figure-03, which shows the schematic view of an oil pump assembly. It comprises housing (1), cover plate (2), pump (3), strainer body (5) and pressure relief valve (8). The pump inlet (4), direction of rotation of pump when the gearbox is rotating vehicle wise, oil path (6) and pump outlet (7) can also be seen in Fig.3. The oil pump assembly is mounted inside the gearbox with 8 mounting holes namely al to hi. When the gearbox rotates vehicle wise, direction of rotation of pump is as shown in Figure-03. In this case, the oil flows through oil path (6).
Referring to figure-04, which shows the front side view of pump housing assembly. Oil path for vehicle wise rotation of the gearbox is marked by arrows. Section E-E represent the cross sectional area of oil path. Section C-C shows the pressure relief valve having 7 mm diameter hole (13).
For the reversed pump direction in slave gearbox, a new oil path is created in the pump housing plate. The pump housing plate is strengthened by filling filler material on the rear wall of pump housing plate (1), shown as filler material filled (10) in Fig.5. To avoid oil leakage through housing plate (1) and cover plate (2), two mounting holes on the cover plate (2) are blocked by sealant, shown as 'mounting holes blocked' (12) in Fig.5.

Referring to figure-06, which shows the new pump housing plate (1) (Filler material filled-10). Oil pump inlet (16) of diameter 7 mm (13). Original pump inlet (4) was blocked by using M24 bolt (18). Strainer body (5) was removed from the original pump inlet (4).
The new pump assembly without modification (17) was tested on gear box assembly test bench by simply rotating it anti vehicle wise as required for slave gear box. The flow rate at the output was measured and was found to be 75 % of the required value. Further improvement was achieved by increasing the existing hole diameter i.e. 7mm (13) to 12mm (17) in new pump inlet (16). This was tested again and required oil flow rate was confirmed. This modified pump assembly was assembled in slave gear box (fig.7) and the rig setup was made as per Method 1 i.e. in back to back manner. The gearbox was run on rig to check that the oil reaches to all the locations inside the gearbox.
The test rig has run so far 1300 hrs without any problem from lubrication point of view. Both the gear boxes were periodically inspected after 200, 400, 600, 900 & 1250 hours thoroughly for any failure and abnormalities. No problem was found which could be attributed to the modification done in slave gear box.
The parts described so far are as mentioned below:
1. Pump housing
2. Cover plate
3. Pump
4. Original pump inlet
5. Strainer body
6. Original oil path
7. Original pump outlet
8. Pressure relief valve
9. Pump housing mounting holes (8 Nos.)

10. Filler material filled (hatched portion)
11. Original holes (11) blocked by Filler material
12. Mounting holes blocked by sealant
13. Diameter of hole
14. Original oil path blocked by sealant
15. New oil path
16. New pump inlet by removing pressure relief valve & by sr. no. 17.
17. Increased Diameter hole
18. Original pump inlet blocked by bolt (M24) & strainer body removed
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

CLAIM
1. Oil circulation system of slave gear box for testing gearbox on test bench
comprising;
slave gear box connected to gear box for rotating anti vehicle wise;
inlet hole for entry of oil in the pump assembly of said slave gear box;
oil path generated on the said front side of said pump housing for circulating the oil;
filler material filled in rear side portion of said pump housing to strengthen pump housing plate, avoid leakage and facilitate oil circulation through the said oil path generated;
outlet for connecting the said oil path to oil gallery for distributing oil in the main shaft to facilitate the oil circulation inside the gear box in anti vehicle wise rotation of slave gear box shaft.
2. Oil circulation system of slave gear box as claimed in claim 1 wherein, said oil pump housing comprises plurality of holes provided therein for mounting to the gear box.
3. Method of providing oil circulation system in slave gear box comprising the steps of:

a) selecting the pump housing from the existing system;
b) creating the new oil path on front side of said pump housing;
c) filling the filler materials at the rear side of said pump housing to avoid leakage and facilitate oil circulation through the said new oil path generated;
d) removing the pressure relief valve and increasing the hole diameter size to provide new pump inlet on said pump housing;
e) providing outlet on said pump housing;
f) removing strainer body from original pump inlet and blocking original pump inlet by blocking means;

g) blocking of two mounting holes with the help of sealant
4. Slave Gear box oil circulation system as herein substantially described with reference to the accompanying drawings.
5. Method of providing oil circulation system in slave gear box as herein described substantially with reference to accompanying drawings.
Dated this 31st day of December 2008