FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION (See Section 10; rule 13)
TITLE OF THE INVENTION
Steering system testing apparatus and method of testing thereof
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Mr. Swapnil R. Salunkhe, Mr. Hari Srinivas Babu Aggarapu
both Indian nationals
of TATA MOTORS LIMITED an 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 describes the invention

Field of invention :
This invention relates to apparatus used for testing automobile systems and more particularly it relates to apparatus and method of testing steering system.
Background of invention:
Steering system test is required to know the interaction of various steering system components with each other. It also provides the possible deterioration in steering component performance over a period of time.
In the conventional test method, the steering system components are assembled partially on test fixture and actual vehicle parts. The layout dimensions are ensured as per the vehicle layout. For generating steering reaction loads, the steering knuckle is attached with additional bracket to which reaction hydraulic load cylinder is attached. During the steering system test, the steering input turns are applied through the hydraulic motor attached to steering shaft. The steering reaction load is generated by restricting the oil flow out of the reaction cylinder. The steering system level tests involve the steering system components from steering wheel to road wheel. The system level test on a steering system conducted for determining deterioration in steering system components.
Objects of invention
The main object of this invention is to provide a Steering system testing apparatus and method of testing thereof by eliminating unwanted artificial force.


Yet another object of this invention is to provide a Steering system testing apparatus and method of testing thereof which requires low set up time.
Yet another object of this invention is to provide a Steering system testing apparatus and method of testing thereof which is simple in construction and cost effective.
Brief description of the invention
Steering system testing apparatus in accordance with this invention basically comprises of hydraulic motor, encoder, steering wheel adaptor with shaft, wheel mounting plates, anchoring unit and hydraulic motor mounting means. Wherein said hydraulic motor is connected to steering wheel adapter with shaft, said assembly of hydraulic motor and steering wheel adapter with shaft is connected to steering wheel of a vehicle under test. Said encoder is mounted on hydraulic motor. Said hydraulic motor is mounted on a hydraulic motor mounting means and is powered by a hydraulic source. Said wheel mounting plates are adopted to put under the front wheels of a vehicle under test. Said anchoring unit is adapted to fix rigidly to the flat surface to anchor front of vehicle.
In the test method, vehicle on road wheels is used directly for conducting the steering system durability test. The vehicle on wheels with complete steering system component assembled is parked on level surface. A hydraulic motor is connected to steering wheel using suitable adopter. The static steering resistance load is generated by loading the vehicle in front to get the front axle weight reaction. The total number of steering turns is controlled using n-coder data at steering input. The durability cycle is conducted by turning the hydraulic motor with hydraulic assistance through one complete steering turn from right hand turn to left hand turn back to right hand turn.


The steering wheel is connected to hydraulic motor. The number of motor turns is controlled by encoder data. For generating steering reaction load the vehicle is loaded to stimulate front axle weight. The friction at front tyres is ensured by placing the steel plate below each front wheels.
Detail description of the invention :
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same,
Figl. shows steering system test apparatus fitted to vehicle in accordance with this invention Referring to fig. 1
Steering system testing apparatus in accordance with this invention comprises of hydraulic motor (4), encoder (7), steering wheel adaptor with shaft (6), wheel mounting plates (9), anchoring unit (3) and hydraulic motor mounting means (10). Wherein said hydraulic motor (4) is connected to steering wheel adapter with shaft (6), said assembly of hydraulic motor and steering wheel adapter with shaft is connected to steering wheel (5) of a vehicle under test. Said encoder (7) is mounted on hydraulic motor (4). Said hydraulic motor is mounted on a hydraulic motor mounting means and is powered by a hydraulic source. Said wheel mounting plates (9) are adopted to put under the front wheels (11) of a vehicle under test. Said anchoring unit (3) is adapted to fix rigidly to the flat surface (2) to anchor front of vehicle (1).
In this test method, vehicle (1) on road wheels is used directly for conducting the steering system durability test. The said vehicle on wheels with complete steering system component assembled is placed on flat surface (2). The vehicle is anchored by said anchoring unit (3) on said flat surface to arrest unwanted vehicle movement as a result of steering inputs. Also care is taken that the vehicle


anchoring is not imposing additional weight component in front axle weight. Said encoder (7) with adopter is connected to sense the number of steering input turns in left hand & right hand complete turns. The static steering resistance load is generated by providing load (8) at the front of vehicle as per specified front axle weight reaction. The total number of steering turns is controlled using encoder (7) data at steering input. The durability cycle is conducted by turning the hydraulic motor (4) through one complete steering turn from right hand turn to left hand turn back to right hand turn.
Method of testing steering system in accordance with this invention comprises of:
a. The vehicle is loaded to prescribed front axle weight. The front axle weight
is measured by placing load cell under front wheels (11). The load cells are
removed after completion of measurement.
b. The input torque performance of the steering system is measured by
connecting a torque load cell between hydraulic motor (4) and steering
wheel with adopter shaft (6). The torque load is disconnected after
completion of measurement.
c. The steering wheel (5) is connected back to hydraulic motors (4) via
steering wheel with shaft adopter (6).
d. The hydraulic motor (4) is supplied with hydraulic assistance. The
assistance pressure is maintained just sufficient to rotate the connected
steering wheel.
e. The hydraulic flow is adjusted to get approximately 8 to 9 test cycles per
minute.
f. The encoder (7) data is set in the controller for controlling number of turns
in clockwise and anti clockwise directions.
g. For starting the tests the hydraulic assistance is supplied to hydraulic motor,
the rig controller is switched ON. The number of endurance cycles is
measured using a cycle counter connected to rig controller.


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.