Method for air testing hydraulic brake components
First Claim
1. A method of testing a hydraulic control unit for controlling the application of pressurized liquid to a hydraulically actuated device, the control unit having an inlet port adapted to be connected to a means for supplying pressurized liquid and an outlet port adapted to be connected to the hydraulically actuated device, the control unit further having valve means connected between the control unit inlet and outlet ports for selectively controlling the liquid pressure at the control unit outlet port and positive displacement liquid pump means having an inlet port communicating with the valve means and a discharge port communicating with the control unit inlet port, the pump means being selectively operable to supply pressurized liquid to the valve means, the test method comprising the steps of:
- (a) providing a hydraulic control unit;
(b) providing means for sensing the rate of change of the gas pressure at the inlet port of the hydraulic control unit;
(c) applying a pressurized gas to the outlet port of the hydraulic control unit;
(d) operating the valve means and the pump means in a predetermined sequence to supply pressurized gas to the pump means inlet port; and
(e) simultaneously with step (d), monitoring the rate of change of the gas pressure sensed in step (b) to determine whether the pump means is operable.
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Accused Products
Abstract
A production functional test for hydraulic brake control and traction control units which utilizes compressed air as a test medium. Compressed air is applied to an external port of a hydraulic brake or traction control unit which includes valves, accumulators and a positive displacement pump driven by an electric motor connected by internal passageways. The air pressure at another external port is monitored while the various components are exercised according to a test sequence. The monitored pressure must be within predetermined limits at various points of the test to demonstrate that the brake control unit is functioning properly. Air flow rates and pump motor current are also measured at specific points in the test. The test method can identify incorrectly sized and installed components.
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Citations
27 Claims
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1. A method of testing a hydraulic control unit for controlling the application of pressurized liquid to a hydraulically actuated device, the control unit having an inlet port adapted to be connected to a means for supplying pressurized liquid and an outlet port adapted to be connected to the hydraulically actuated device, the control unit further having valve means connected between the control unit inlet and outlet ports for selectively controlling the liquid pressure at the control unit outlet port and positive displacement liquid pump means having an inlet port communicating with the valve means and a discharge port communicating with the control unit inlet port, the pump means being selectively operable to supply pressurized liquid to the valve means, the test method comprising the steps of:
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(a) providing a hydraulic control unit; (b) providing means for sensing the rate of change of the gas pressure at the inlet port of the hydraulic control unit; (c) applying a pressurized gas to the outlet port of the hydraulic control unit; (d) operating the valve means and the pump means in a predetermined sequence to supply pressurized gas to the pump means inlet port; and (e) simultaneously with step (d), monitoring the rate of change of the gas pressure sensed in step (b) to determine whether the pump means is operable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of testing a hydraulic control unit for controlling the application of pressurized liquid to a hydraulically actuated device, the control unit having an inlet port adapted to be connected to a means for supplying pressurized liquid and an outlet port adapted to be connected to the hydraulically actuated device, the control unit further having valve means connected between the control unit inlet and outlet ports for selectively controlling the liquid pressure at the outlet port and a hydraulic fluid storage means communicating with the valve means, the storage means having an axially movable piston disposed within a bore formed in the control unit and a resilient means to bias the piston within the bore, the test method comprising the steps of:
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(a) providing a hydraulic control unit; (b) providing means for sensing the rate of piston displacement within the bore; (c) applying a pressurized gas to the outlet port of the hydraulic control unit; (d) operating the valve means in a predetermined sequence to axially displace the piston within the bore; and (e) simultaneously with step (d) , monitoring the rate of piston displacement sensed in step (b) to determine whether the storage means is operable. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification