Title of Invention

INERTIA BRAKE DYNAMOMETER

Abstract

An inertia brake dynamometer for a vehicle comprising an electrical prime mover for driving the brake assembly to be tested; a power control unit for supplying power to the prime mover a chuck in which the brake parts to be tested are held; a PLC based master controller for providing the signals to the power control unit for operating the prime mover in the motor mode/dynamometer mode, I the master controller being programmed for various input parameters of the vehicle, and for providing the signal to force application means; a force gauge for measuring the applied force; and torque measuring means for measuring the torque.

Full Text

This invention relates to an inertia brake dynamometer" Normally inertia brake dynamometers are used for laboratory based evaluation of brake system components. The known dynamometer consists of a drive motor, detachable flywheels which represent the rotating mass. The flywheel masses can be increased or decreased through a locking pin arrangement. The drive motor has a main shaft for driving the flywheels supported by a pedestal support. The system has a force application mechanism, which actuates the brake lever of the brake assembly to be evaluated. The applied force is measured by any known type of force gauge. This force gauge is actuated through a cable/wire The brake assembly to be evaluated is assembled in a chuck mechanism at the free end of the drive m otor. Based on calculation, the size of flywheel is rounded off and fitted at the end of drive motor for simulation and evaluation of the braking performance. Using the above arrangement, the braking torque of the system is determined by the turning moment of brake panel, which is product of the output of force gauge and centre distance between brake panel axis / force gauge mounting point. The above system has the following drawbacks, 2) Furthermore the huge rotating mass is unsafe at higher speeds, more wear and tear of mechanical parts that leads to frequent maintenance of test rig and so on. Also, the inertia is rounded off to the nearest values due to constraints in flywheel mass. The testing time is relatively more in this system as it has to accelerate the whole mass to reach the test speed. 3) The input force imposed on the brake lever is not constant throughout the brake application since the direction of actuation of force is not perpendicular to the axis of lever. 4) ftake torque is not obtained directly and every time calculation needs to be done. Accuracy of brake torque is affected due to inclusion of mass of aim, brake panel, vibration of brake panel during braking, maintaining perpendicularity of arm and so on Calibration needs to be done whenever the brake lever length changes. 5) Furthermore the wear and tear caused by the elongation of mounting point can generate some spikes in the measured force values. Whenever there is change in the design and construction of the brake panel for measuring the braking torque, there is a need to redesign test rig setup. 6) The above system cannot simulate custom built test run cycle to perform the actual customer usage condition. In order to overcome the above problems, we hove proposed th« inertia brake dynamometer according to this invention. The inertia brake dynamometer for a vehicle, according to this invention, comprises an electrical prime mover for driving the brake assembly to be tested; a power control unit for supplying power to the prime mover, a chuck in which the brake parts to be tested are held; a PLC based master controller for providing the signals to the power control unit for operating the prime mover in the motor mode/dynarnometer mode, the master controller being programmed for various input parameters of the vehicle, and for providing the signal to force application means; a force gauge for measuring the applied force; and torque measuring means for measuring the torque. In the dynamometer proposed herein the force application mechanism has a linkage arm mounted on a force actuator, said linkage arm connecting the brake lever of the said brake assembly through the said force g^uge, by a flexible linkage, the said brake lever and linkage arm being aligned to the pivot axis, the force being applied such that the force gauge is always perpendicular to the axis of the lever. In the said dynamometer proposed herein the torque measuring means comprise a torque measuring flange wherein the rotor of the said flange has a strain gauge mounted thereon, said rotor having transmitter coils for transmitting signals to an antenna and from there to the master control unit This invention will now be described with reference to the accompanying drawings which illustrate the known dynamometer, and by way of example, and not by way of limitation, one of various possible embodiments of this invention Figure 1 illustrating a schematic layout of the dynamometer as known to the art Figure 2 illustrating a schematic layout of the embodiment Figure 3 illustrating a schematic layout of the force actuating mechanism pertaining to the said embodiment Figure 4 illustrating a schematic layout of the torque measurement means pertaining to the said embodiment The known dynamometer consists of a drive motor (1), detachable flywheels (2) which represent the rotating mass. The flywheel masses (2) can be increased or decreased through a locking pin (3) arrangement The drive motor has a main shaft (5) for driving the flywheels (2) supported by a pedestal support (4). The system has a force application mechanism, which actuates the brake lever of the brake assembly (7) to be evaluated. The applied force is measured by a force gauge (8). This force gauge (8) is actuated through a cable/wire The brake assembly (7) to be evaluated is assembled in a chuck mechanism (6) at the free end of the drive motor. Based on cdculation, the size of flywheei is rounded off and fitted at the end of drive motor for simulation and evaluation of the braking performance. Using the above arrangement, the braking torque of the system is determined by the turning moment of brake panel, which is product of the output of force gauge and centre distance between brake panel axis / force gauge mounting point The proposed arrangement shown in Figure 2 consists of an electrical prime mover (10). The prime mover (10) drives the brake parts (70) to be tested which are fitted on a chuck (60), The power supply to the prime mover (10) is given via cables (30) by a power control unit (40). The signal to the power control unit (40) for operation of the prime mover (10) in motoring mode / dynamometer mode is done by PLC based (programmable logic control) master controller (50). A cooling blower (20) is provided for cooling during operation of the prime mover (10). The master controller (50) can be programmed for various vehicle input parameters like static rolling radius of the brake wheel, gross vehicle weight type of brakes, direction of rotation etc for controlling the speed, vehicle inertia, brake input force and so cm. The complete system is fitted to a rigid base (90). The master controller (50) provides signal for force actuation mechanism, a force gauge (80) to the brake system. The above system can simulate inertia precisely without any rotating mass like mechanical flywheels. Input parameters like static load radius of type of wheel where the brake under test is normally fitted, mass of vehicle to be simulated and so on are fed to the controller. IXiring acceleration, the prime mover acts as a drive motor and drives the brake drum fitted on the chuck parte till it reaches the test speed It remains for a stipulated lime in that test speed and during braking it absorbs the road load, which is predetermined by the master control unit calculated based on above said input parameters. Thus the proposed inertia simulation technique enables in improving the efficiency of testing when compared to the known arrangement given in figure 1. Since this is a non-mechanical system, wear and tear of machine, maintenance will be relatively less when compared to known inertia brake dynamometers. As shown in figure 3, the force application mechanism has a linkage aim (100), which is mounted on the force actuator (101). The brake to be tested has a brake lever (102) of brake assembly (70) of Fig 20 mounted on a supporting bracket (103). The link^e arm (lOCf) connects the brake lever (102) through force gauge (80) of Fig 2> which is connected through a flexible linkage (104). The brake lever (102) and linkage arm (100) is aligned to pivot axis (105). The force is actuated hi such a way that the force gauge (80) of Fig 2 is always perpendicular to the lever axis throughout the force actuation. Figure 4 shows the proposed torque measuring system. This comprises a drive motor (10) of Fig2 cum dynamometer for inertia simulation, fitted to a rigid base (90) of Figure 2. The brake drum (201) of brake assembly (70) of Fig 2 is fitted in the chuck part (60) of Fig 2 The brake shoe (202) to be tested is fitted to the brake panel (203). The brake torque is measured in the wheel nub (204) directly with a known torque-metering flange. The torque flange consists of two different parts rotor (205) and the stater (206), The rotor (206) is the measuring body where the torque is experienced. Strain gauge is mounted on the rotor measuring body. The rotor located centrally on the flange has an inbuilt electronic device for transmitting the bridge excitation volt^e and measuring signal. The rotor has the transmitter coils for non-contact transmission of excitation voltage and measuring signal. The transmitted signals are received by a divisible antenna ring. The antenna ring is mounted on a housing that includes Ihe electronic system for the voltage adoption and signal conditioning. Now during rotation the torque experience by the rotor is directly transmitted to the receiver. Hie torque signal output is sent to the master control unit (50) of figure 2. Thus the torque is measured directly on the main shaft of motor. The above system is aided by a software package, which interfaces the maser controller (50) of fig 20 and driver motor (10) of figure 2. The features of the software are as follows. a) Input parameters such as vehicle parameters like tyre diameter, road load coefficients, brake input force, initial and final speed and so on. b) Formulation of test cycles. c) Calibration of sensors. d) Output parameters such as stopping distance, stopping time, mean fully developed deceleration, temperature at various locations, and so on. The terms and expressions herein are of description and not of limitation since various other embodiments of the dynamometer proposed herein without departing from the scope and ambit of this invention We Claim: l.An inertia brake dynamometer for a vehicle comprising an electrical prime mover for driving the brake assembly to be tested; a power control unit for supplying power to the prime mover; a chuck in which the brake parts to be tested are held; a PLC based master controller for providing the signals to the power control unit for operating the prime mover in the motor mode/dynamometer mode, the master controller being programmed for various input parameters of the vehicle, and for providing the signal to force application means; a force gauge for measuring the applied force; and torque measuring means for measuring the torque. 2.A dynamometer as claimed in Claim 1 wherein the force application mechanism has a linkage arm mounted on a force actuator, said linkage arm connecting the brake lever of the said brake assembly through the said force gauge, by a flexible linkage, the said brake lever and linkage arm being aligned to the pivot axis, the force being actuated such that the force gauge is always perpendicular to the axis of the lever. 3.A dynamometer as claimed in Claim 1 or Claim 2 wherein the torque measuring means comprise a torque measuring flange wherein the rotor of the said flange has a strain gauge mounted thereon, said rotor having transmitter coils for transmitting signals to an antenna and from there to the master control unit. 4.An inertia dynamometer for a vehicle substantially as herein described with reference to Figs 2 to 4 of the accompanying drawings.

Documents:

741-che-2004-abstract.pdf

741-che-2004-claims duplicate.pdf

741-che-2004-claims original.pdf

741-che-2004-correspondnece-others.pdf

741-che-2004-correspondnece-po.pdf

741-che-2004-description(complete) duplicate.pdf

741-che-2004-description(complete) original.pdf

741-che-2004-drawings.pdf

741-che-2004-form 1.pdf

741-che-2004-form 19.pdf

741-che-2004-form 26.pdf

741-che-2004-form 3.pdf