Abstract:
The invention relates to a method for representing a hydraulically working receptor by simulating the characteristic pressure and volume intake of the pressure fluid receptor on a test bench. The characteristic pressure and volume intake of the pressure fluid receptor is represented by at least a first and a second simulation segment (I, II), wherein the pressure/volume characteristics of a gas are set to be represented in the first simulation segment and the pressure/volume characteristics of a liquid are set to be represented in the second simulation segment.
Abstract:
A vehicle brake leakage detector (10) installs between a vehicle brake pedal and a reference point (18) such as a steering wheel, for testing vehicle hydraulic brake systems, and, specifically, for detecting brake fluid leaks. A brake contact (12) at one end of the detector contacts the vehicle brake pedal and a reference end (18) at the opposite end of the detector contacts any tangible reference location, such as a steering wheel. Force means such as such as springs (42, 44) are associated with the detector is installed. A sensor (26) monitors for and detects any relative movement between the brake contact (12) and reference end (18) to determine whether any brake fluid leaks are present. An output source (28) indicates whether any brake fluid leaks are detected.
Abstract:
The invention relates to a process and a testing device for testing an anti-lock control system in pressure-medium-actuated vehicle brakes using the existing braking pressure in the system, in which the anti-lock braking system (ABS) has a control unit which is connected for control purposes with brake pressure control valves allocated to individual wheels. The present invention is based on the knowledge that the control cycles exerted by the ABS control unit on the individual brake pressure control valves are also felt even at the brake pedal in the form of flutter. In the process of the invention, the actuating frequency of at least one vehicle wheel control valve when the ABS responds is felt at the brake pedal itself as braking pressure-dependent pedal travel changes. The test device of the invention has to that end a sensor to detect the pedal travel when the control system responds, whereby said sensor is connected to an evaluation device via electric leads or wireless data transmission.
Abstract:
Brake tester roller comprising replaceable lining layer and consisting of a rotating support (1) and two or more removable semi-cylindrical shells (2, 3), the outer surface of which is non-slip, secured on said roller by screws or any other equivalent means. The device of the invention is suitable for use in industrial applications involving equipment for mechanical workshops. It is intended to be fitted to brake testing systems for light, utility and heavy-goods vehicles.
Abstract:
The invention concerns a dynamic roadway test stand with which the running characteristics of a motor vehicle wheel (12) on a roadway can be tested. To also facilitate the measurement of braking applied to high-inertia bodies corresponding to fast-moving heavy motor vehicles, the drive (2) of a flat belt (6) simulating a roadway (6) is coupled to a flywheel mass test rig (1) for brake testing. Further embodiments of the invention concern the simulation of water levels on the road surface and extreme ambient temperatures and airflows. The test stand according to the invention is particularly suitable for simulating undulations in the road surface and the fluctuations in the load exerted on the braked wheel.
Abstract:
The frictional properties test mechanism (10) comprises a shaft dynamometer (12) connected with a wheel element (14) that is coupled with a braking mechanism (16) for the wheel element (14). The braking mechanism comprises a single rotor (25)/double stator (27) disc brake whose torque tube (29) is attached to a piston housing (40) and torque load cell (54). The piston housing (40), torque armature end plate (41), and torque load cell (54) are mounted by way of bearings (95) within a stationary framework (100), and connected with an oscillatory motion mechanism (18). Located adjacent the stationary framework (100) and connected by arms (24) to the end plate (41) and torque load cell (54) is a pair of spring mechanisms (20) and a pair of hydraulic cylinders (22), which are part of the oscillatory motion mechanism (18). A control and display console (121) operates the dynamometer (12) in order to effect rotary motion of the wheel element (14) and operation of the braking mechanism (16). The oscillatory motion mechanism (18) imparts a slight oscillatory or sinusoidal motion to the end plate (41), torque load cell (54), piston housing (40), torque tube (29) and stators (27) via the hydraulic cylinders (22), spring mechanisms (20), and arms (24). The sinusoidal motion of the stators (27) effects in incremental velocity and incremental torque and enables the determination, via a high speed data acquisition system (190) and computerized data reduction (120, 122, 123), of frictional properties of the brake mechanism (16). A pressure pulse from a generator (130) to the piston housing (40) is used to determine a torque/pressure transfer function, and the variation of frictional properties with temperature is determined by controlling the temperature of the brake friction pair (25, 27) via heater elements (80, 83).
Abstract:
A method of evaluating the operational characteristics of a brake booster by simulating a brake application of partially assembled brake booster components. An input force to control valve located in a hub of a shell to create an output force which is communicated through a reaction disc to a output member. An initial operational curve corresponding to an output force is compared with a reference curve to either accept or reject the partially assembled brake booster components. If accepted, additional components are joined to the partially assembled booster to complete the assembly. If rejected, spacers based on the operational characteristics of the reactions disc and initial operational curve are located adjacent the reaction disc to modify the communication of a pressure differential developed force to the reaction disc for the now modified partially assembled brake booster components. An input force is again applied to the control valve to simulate a second brake application. The pressure differential developed force is communicated through the spacers to produce a second operational force. A curve corresponding to the second operational force is compared with the reference curve to inform an operator to either accept or reject the modified partially assembled brake booster components. If accepted, additional components are thereafter joined to the modified partially assembled brake booster components to complete the assembly. If rejected, the modified partially assembled brake booster components are removed from the assembly line.
Abstract:
The brakes of a two-axle vehicle (3) are tested by weighing the vehicle and measuring the braking forces for both axles to determine the actual ratio of front axle braking force to total braking force. The deceleration (63) applied to the vehicle is determined from the weight of the vehicle and the applied braking forces. A nominal preferred value (67) of the ratio of front axle braking force to total braking force is calculated from the determined deceleration and the measured weight of the vehicle (60). For each test, upper (69) and lower limits (65) for the acceptability of the actual ratio of front axle braking force to total braking force are set based upon the computed nominal preferred value. The nominal preferred value, the movable limits, and the actual ratio are displayed to the user on a CRT screen (21). The actual ratio is displayed in the form of a bar on the screen, with the limits and nominal preferred value displayed as non-numeric indicia along the longitudinal axis of the bar.
Abstract:
A vehicle restraint system (30) for testing vehicles (21) has vehicle restraint linkages (35, 75, 120) which couple to a vehicle (21) mounted on a simulated roadway (12) to provide restraint in selected axes and to permit freedom of movement in other axes in a manner that permits the vehicle (12) to react as it would when being driven over an actual roadway. The restraint system (30) is made to combine and limit lateral, longitudinal and yaw motions with a minimum effect on the handling properties in other axes of movement. The restraint system (30) includes selective, active servo positioning in the restrained axes so that the position of the vehicle (21) can be maintained so that the vehicle tires (24) are kept within a load support area of the simulated roadway (12) without substantially affecting the vehicle handling properties. The action of restraint linkages is through the center of gravity (25) of the vehicle (21). The three restrained axes are decoupled from each other so that the restraint in each axis does not substantially affect the other axes.