Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Reexamination Certificate
1998-08-26
2001-05-01
Graham, Matthew C. (Department: 3613)
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
C251S129150
Reexamination Certificate
active
06224170
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a hydraulic control valve device for an anti-lock braking system (ABS hereinafter) and a traction control system (TCS hereinafter). More specifically, it relates to a hydraulic control valve device which uses a wide open channel during normal braking operation and uses a throttled channel during hydraulic pressure control.
A hydraulic brake device, which prevents wheel locking by electronically controlling brake hydraulic pressure when at full braking or sudden braking, is publicly known. This type of device is well-known to create noise, vibration, harshness (NVH) such as a metal sound or vibration when the electromagnetically operated normally open valve (hydraulic control valve device hereinafter) is closed. In order to resolve NVH, there exists a method of providing an independent differential pressure switching valve at the upstream side of the hydraulic control valve device of the main hydraulic braking line.
The above-described conventional method to eliminate NVH is effective to a certain degree. Metal sound or vibration, however, could not completely be eliminated which leaves room for an improvement.
OBJECTS AND SUMMARY OF THE INVENTION
The main object of this invention is to resolve the above-identified problems. To that end, this invention provides a hydraulic control valve device which further improves the reduction of the NVH effect.
Another object of the invention is to provide a hydraulic control valve device which prevents malfunction of the device.
Another object of the invention is to provide a hydraulic control valve device which enables smooth pressure reduction with certainty when releasing the braking force.
The first aspect of invention is to provide a hydraulic control valve which comprises a sleeve fixed in a bore of a housing, an armature which is slidably installed in the sleeve including a valve stem with a valve member on a distal end thereof, a magnet core fixed in the bore of the housing together with the sleeve, the magnet core having a smaller diameter portion extending into the bore, a coil assembly operating the armature by an electromagnetic force, a piston strokably provided in the smaller diameter portion of the magnet core, a valve seat formed on an end surface of the piston facing the valve member, and a spring provided between the piston and a bottom of the bore absorbing operation impact created when the valve member contacts the valve seat.
The second aspect of invention is to provide a hydraulic control valve device as above, wherein a release channel is formed either between the piston and an inner surface of the smaller diameter portion of the magnet core or at the piston.
The third aspect of the invention is to provide a hydraulic control valve device as above, further comprising a reverse stop valve formed to prevent a flow through the release channel, the stop valve including a cylindrical protuberance formed on one of the end surface of the valve seat side of the piston or a stepped portion in the smaller diameter portion of the magnet core facing the end surface of the valve seat side of the piston, flow through the release channel being stopped by the cylindrical protuberance and the end surface of the valve seat side abutting against the cylindrical protuberance or the stepped portion in the smaller diameter portion.
The fourth aspect of the invention is to provide a hydraulic control valve device which comprises a normally open inlet valve in a main hydraulic line between a master cylinder and a wheel cylinder and a hydraulic switching valve at a wheel cylinder side of the inlet valve in the main line, wherein the switching valve controlling a channel between the master cylinder and wheel cylinder to be wide open when in a normal braking operation and a hydraulic pressure difference between the master cylinder side and wheel cylinder side switching the channel to be throttled when in a hydraulic control. The inlet valve comprises a sleeve fixed in a bore of a housing, an armature slidably installed in the sleeve including a valve stem with an inlet valve member at a distal end thereof, a magnet core fixed in the bore of the housing with the sleeve, through which the inlet valve member is inserted, the magnet core having a smaller diameter portion extending into the bore, a coil assembly electromagnetically operating the armature, an inner piston slidably provided in smaller diameter portion of the magnet core, an inlet valve seat formed on the surface of the inner piston facing the inlet valve member of the armature, and an inner spring provided between the inner piston and a bottom of the bore absorbing an impact created when closing the valve mechanism of the inlet valve member and inlet valve seat. The switching valve comprises: an outer piston which is slidably provided exterior on the smaller diameter portion of the magnet core dividing the bore into a first hydraulic chamber connected to the master cylinder and a second hydraulic chamber connected to the wheel cylinder, an outer spring pressing the outer piston toward the bottom of the bore, and a connection bore provided through the smaller diameter portion of the magnet core to connect the master cylinder side and the wheel cylinder side and defining the channel, wherein the outer piston slides along the smaller diameter portion of the magnet core in response to the hydraulic pressure difference between the master cylinder side and wheel cylinder side as occurring in the first and second hydraulic chambers, respectively, in the direction to switch the channel from being wide open to being throttled.
The fifth aspect of the invention is provide a hydraulic control valve device as above, wherein a release channel is formed either between the piston and an inner surface of the smaller diameter portion of the magnet core or at the piston; whereby hydraulic pressure of the wheel cylinder is released to the master cylinder via the release channel when the hydraulic pressure of the master cylinder falls below the predetermined amount from the hydraulic pressure of the wheel cylinder.
The sixth aspect of the invention is to provide a hydraulic control valve as above, further comprising: a reverse stop valve formed to prevent a flow through the release channel, the stop valve including a cylindrical protuberance formed on one of the end surface of the valve seat side of the piston or a stepped portion in the smaller diameter portion of the magnet core facing the end surface of the valve seat side of the piston, flow through the release channel being stopped by the cylindrical protuberance and the end surface of the valve seat side abutting against the cylindrical protuberance or the stepped portion in the smaller diameter portion.
The seventh aspect of the invent ion is to provide a hydraulic control valve device as above, further comprising: a retainer ring contacting the bottom of the bore and extending into the smaller diameter portion of the magnet core, wherein a throttle channel is formed between the retainer ring and the smaller diameter portion of the magnet core, and a main channel of the master cylinder side and the first hydraulic chamber are connected via the throttle channel.
The eighth aspect of the invention is to provide a hydraulic control valve device as above, further comprising: a holding plate formed on the retainer ring, and a sealing device inserted between an outer surface of the smaller diameter portion of the magnet core and the bore, the sealing member being held by the holding plate.
REFERENCES:
patent: 5203617 (1993-04-01), Wilde
patent: 5673979 (1997-10-01), Kuromitsu et al.
patent: 5673980 (1997-10-01), Schwarz et al.
patent: 5704587 (1998-01-01), Kuromitsu et al.
Arent Fox Kintner Plotkin & Kahn
Graham Matthew C.
Nisshinbo Industries Inc.
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