FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"MOBILE TEST BENCH FOR DRAG AND WHINE NOISE MEASUREMENT"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C, SATPUR,
NASHIK-422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES AND ASCERTAINS THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION:-
Present invention relates to a mobile test bench for drag and whine noise measurement.
Drag means resistance to rotate freely. This is caused by bearings, oil in the gear box, inertia of gears, shafts & etc.
To measure this drag for a given gear box, magnetic clutch is used on this mobile test rig.
A given transmission is mounted on the mobile test rig (MTR), Magnetic clutch is mounted in the test system, as per the figure. The magnetic clutch is just before the transmission, so that exact drag of the system can be measured.
Magnetic clutch has a very fast response of 20 ms for engagement & disengagement
OBJECT OF THE PRESENT INVENTION:-
Object of the present invention aims at developing a mobile test bench for drag and whine noise measurement.
STATEMENT OF INVENTION:-
Accordingly the invention provides a mobile test bench for drag and whine noise measurement comprises mobile platform provided with cardan shaft mounted in a pair of first set bearing with centre tripod joit; at one end of said shaft a motor to drive by means belt; the other end of said shaft a hook joint attached to connect to driving end of magnetic clutch supported on a pair of second set of bearing; and a clamping means provided to the driven end to connect transmission device under test.

DRAWING:-
Invention is described with reference to the figure of accompanying drawing wherein;
Figure 1 shows the mobile test bench for drag and whine noise measurement according to invention.
BRIEF DESCRIPTION OF THE INVENTION:-
This Mobile test bench is built on a frame with wheels to conduct trials at any location. This Test bench on frame consists of drive Motor, cardan shaft, bearing, magnetic clutch, support mounts and compact loading dynamometer to simulate part load.
Referring to figure 1 A mobile platform provided test bench for drag and whine noise measurement. The test bench comprises cardan shaft mounted in a pair of first set bearing with centre tripod joint. At one end of said shaft a motor to drive by means of belt provided to drive the said shaft. The other end of the said shaft a hook joint attached to connect to driving end of magnetic clutch supported on a pair of second set of bearings. A clamping means provided to the driven end magnetic clutch to connect transmission device under test.
The mobile test bench is also provided with a sliding table for increasing the torque fluctuations online to identify the critical angular acceleration of a given transmission / transaxle.
Drag torque plays measure role for transmission gear rattle noise and gear shifting effort. Simulation of drag torque is not feasible by analytical tools. It needs to be measure on actual transmission for accurate prediction. Measurement and Optimization of drag torque is feasible by using this innovative test bench to reduce the gear rattle noise.

Most of the test benches are fixed on to a determined location, here the above test bench is a mobile system, can be moved according to our requirement. Huge space is required for other test bench with acoustic treatments for Noise measurements, but as the above test bench is mobile, one can move the DAC chassis to the silent anechoic rooms for noise measurements. Drag measurements using Magnetic clutch is a unique concept on a Mobile system.
This Mobile test bench is built on a frame with wheels to conduct trials at any location. This test bench on frame consists of drive Motor, cardon shaft, bearing, magnetic clutch, support mounts and compact loading dynamometer to simulate part load. Innovative magnetic clutch is explored to disengage the transmission from drive and used innovative Hall Effect sensors on different gears to measure the decay time and subsequently drag torque through slope and effective inertia of gears.
METHOD OF TESTING ON THIS BENCH TESTER:-
Drag means resistance to rotate freely. This is caused by bearings, oil in the gear box, inertia of gears, shafts & etc.
To measure this drag for a given gear box, magnetic clutch is used on this mobile test rig.
A given transmission is mounted on the mobile test rig (MTR), Magnetic clutch is mounted in the test system, as per the figure. The magnetic clutch is just before the transmission, so that exact drag of the system can be measured. Magnetic clutch has a very fast response of 20 ms for engagement & disengagement.
Magnetic clutch working
1. Engagement: - When the clutch is required to actuate, current flows through the electromagnet, which produces a magnetic field. The rotor portion of the clutch becomes magnetized and sets up a magnetic loop that attracts the

armature. The armature is pulled against the rotor and a frictional force is generated at contact 2. Disengagement: - When current is removed from the clutch, the armature is free to turn with the shaft. Springs hold the armature away from the rotor surface when power is released, creating a small air gap
Transmission is rotated using a motor with magnetic clutch up to 4000 rpm in all gears engaged one by one. Once the speed is reached 4000 rpm, the magnetic clutch is disengaged, after disengagement all the speed sensors on the gears measure the speed of the gears which is reducing due to drag in the system. After few seconds the transmission comes to stand still.
The measured rpm of all gears from 4000 rpm to 0 rpm is used for drag calculations.
The following formula shows us, how to calculate the value of drag.
Drag Torque =l.α .... α=angular acceleration , I = reflected inertia on the engaged gears
Angular Acceleration = α= ∆ ω /∆t = from the slope of the graph (angular velocity v/s time)
ADVANTAGES OF THE PRESENT INVENTION:-
1. For Measurement of Inertia & Drag torque of any transmission at any location.
2. Angular acceleration measurements can be possible for gear Rattle sensitivity.
3. Gear Misalignments can be determined.
4. Housing Stiffness & Ribbing pattern optimization.
5. Free play & float optimization of gears can be done.
6. Whine noise generation.

WE CLAIM:-
1. A mobile test bench for drag and whine noise measurement comprises mobile platform provided with cardan shaft mounted in a pair of first set bearing with centre tripod joint; at one end of said shaft a motor to drive by means belt; the other end of said shaft a hook joint attached to connect to driving end of magnetic clutch supported on a pair of second set of bearing; and a clamping means provided to the driven end to connect transmission device under test; and a mounts and compact loading dynamometer to simulate part load.
2. The mobile test bench as claimed in claim 1 wherein a sliding table for increasing the torque fluctuations online to identify the critical angular acceleration of a given transmission /transaxle.