Hydraulic braking system
First Claim
1. A hydraulic braking system comprisinga hydraulic brake with a hydraulic fluid chamber, a source of hydraulic fluid for supplying hydraulic fluid at pressure greater than ambient pressure, a first hydraulic valve means having a first switch and a second hydraulic valve means having a second switch, each valve means having a first port, a second and a third port, the first port of the second valve means being connected to the second port of the first valve means, the first port of the first valve being connected to the source of hydraulic fluid, the third ports of the first and the second valve means being connected to the ambience the second port of the second valve means being connected to the hydraulic fluid chamber, the first and the second switch connects the first ports to the second ports and closes the third ports when in a first position and closes the first ports and connects the second ports to the third ports when in a second position, a hydraulic accumulator for the hydraulic fluid under pressure connected to the second port of the first valve means and connected to the first port of the second valve means, whereby the hydraulic pressure in the hydraulic fluid chamber can be controlled by selectively positioning the first and the second switches in there first and second positions so as to control the braking pressure exerted by the hydraulic brake in such a way that preservation of the hydraulic pressure in the fluid chamber during a time period after pressure loss in the hydraulic fluid supplied by the source and for smoothing of the pressure variations in the hydraulic system is obtained.
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Accused Products
Abstract
A hydraulic braking system, method for controlling the hydraulic braking system, and a control system for controlling the hydraulic braking system are provided. The hydraulic braking system may be applied to any kind of moving elements or systems. For example, this system can be used with wind turbines, conveyor systems, etc.
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Citations
34 Claims
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1. A hydraulic braking system comprising
a hydraulic brake with a hydraulic fluid chamber, a source of hydraulic fluid for supplying hydraulic fluid at pressure greater than ambient pressure, a first hydraulic valve means having a first switch and a second hydraulic valve means having a second switch, each valve means having a first port, a second and a third port, the first port of the second valve means being connected to the second port of the first valve means, the first port of the first valve being connected to the source of hydraulic fluid, the third ports of the first and the second valve means being connected to the ambience the second port of the second valve means being connected to the hydraulic fluid chamber, the first and the second switch connects the first ports to the second ports and closes the third ports when in a first position and closes the first ports and connects the second ports to the third ports when in a second position, a hydraulic accumulator for the hydraulic fluid under pressure connected to the second port of the first valve means and connected to the first port of the second valve means, whereby the hydraulic pressure in the hydraulic fluid chamber can be controlled by selectively positioning the first and the second switches in there first and second positions so as to control the braking pressure exerted by the hydraulic brake in such a way that preservation of the hydraulic pressure in the fluid chamber during a time period after pressure loss in the hydraulic fluid supplied by the source and for smoothing of the pressure variations in the hydraulic system is obtained.
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24. A method of controlling a hydraulic brake system, said brake system comprises a hydraulic brake with a hydraulic fluid chamber, a source of hydraulic fluid for supplying hydraulic fluid at pressure greater than ambient pressure, and a hydraulic valve means having a first port connected to the source of hydraulic fluid, a second port connected to the hydraulic fluid chamber, a third port connected to the ambience, a switch which in a first position connects the first port to the second port and closes the third port and which in a second position closes the first port and connects the second port to the third port, whereby the hydraulic pressure in the hydraulic fluid chamber can be controlled by selectively positioning the switch in its first and second positions so as to control the braking pressure exerted by the hydraulic brake,
the method comprises the steps of storing in a memory a prescribed function of velocity of the moving mechanical elements or system as a function of time, determining the velocity at prescribed first time intervals, at each determination of the velocity at the prescribed first time intervals, comparing the determined velocity with a corresponding prescribed velocity, and switching the switch into that of its first and second positions that increases the braking pressure exerted by the hydraulic brake for a prescribed third time interval, if the determined velocity is greater than the corresponding prescribed velocity, and switching the switch into that of its first and second positions that decreases the braking pressure exerted by the hydraulic brake for a prescribed fourth time interval, if the determined velocity is smaller than the corresponding prescribed velocity.
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28. A method of controlling a hydraulic brake system, said brake system comprises a hydraulic brake with a hydraulic fluid chamber, a source of hydraulic fluid for supplying hydraulic fluid at pressure greater than ambient pressure, and a hydraulic valve means having a first port connected to the source of hydraulic fluid, a second port connected to the hydraulic fluid chamber, a third port connected to the ambience, a switch which in a first position connects the first port to the second port and closes the third port and which in a second position closes the first port and connects the second port to the third port, whereby the hydraulic pressure in the hydraulic fluid chamber can be controlled by selectively positioning the switch in its first and second positions so as to control the braking pressure exerted by the hydraulic brake,
the method comprises the steps of storing a determined velocity of the moving mechanical elements or system at a number of time instants, determining the actual acceleration or deceleration of the moving mechanical element or system from the stored values of the determined velocity, determining the actual pressure in the hydraulic fluid chamber at prescribed fifth time intervals, determining the desired pressure in the hydraulic fluid chamber at prescribed sixth time intervals from the determined actual acceleration or deceleration and from the mechanical characteristics of the moving mechanical element or system and of the hydraulic brake, at each determination of the actual pressure comparing the determined actual pressure with the corresponding desired pressure, and switching the switch into that of its first and second positions that increases the braking pressure exerted by the hydraulic brake for a prescribed seventh time interval, if the determined actual pressure is smaller than the corresponding desired pressure, and switching the switch into that of its first and second positions that decreases the braking pressure exerted by the hydraulic brake for a prescribed eighth time interval, if the determined actual pressure is greater than the corresponding desired pressure.
Specification