Fluid handling – Processes – Cleaning – repairing – or assembling
Patent
1998-04-22
1999-08-03
Hepperle, Stephen M.
Fluid handling
Processes
Cleaning, repairing, or assembling
137315, 1374542, F16K 2702
Patent
active
059311797
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on a hydraulic unit for a slip-controlled brake system of a motor vehicle.
A hydraulic unit of this kind has been disclosed, for example, in DE 43 32 538 A1. The known hydraulic unit has a hydraulic block with a receiving bore for a solenoid valve into which a solenoid valve is inserted with its hydraulic part. By means of conduits that feed into the receiving bore, the solenoid valve is hydraulically connected to other hydraulic components of the motor vehicle brake system, which are also partially contained in the hydraulic block and otherwise are disposed externally and connected to the hydraulic block with fluid lines. To fasten the solenoid valve in the receiving bore, material of the hydraulic block in the mouth region of the receiving bore is caulked in an overlapping manner to a flange of the solenoid valve. In this way, the solenoid valve is rigidly held in the receiving bore. After the caulking, a hollow cylindrical magnet coil for actuating the solenoid valve is slid onto a magnet part of the solenoid valve protruding from the hydraulic block.
As a result of small deviations from the ideal position of the solenoid valve in the receiving bore when caulking and as a result of the caulking, the solenoid valve can press against a circumference wall of the receiving bore on the inside of the receiving bore. As a result of alternating stress on the solenoid valve due to fluctuating fluid pressure during the operation of the hydraulic unit, a material displacement occurs at the point at which the solenoid valve presses against the circumference wall, the solenoid valve "digs into the circumference wall of the receiving bore". Diametrically opposite the point at which the solenoid valve displaces material of the hydraulic block, a radial gap between the solenoid valve and the circumference wall of the receiving bore enlarges, wherein the increase of the radial play can become a multiple of the original diametrical play between the solenoid valve and the receiving bore at this point. A sealing cup, which creates a seal between an inlet side and an outlet side of the solenoid valve, can plastically flow ("extrude") into the enlarged radial gap, which leads to a failure of the sealing cup and thereby of the solenoid valve.
ADVANTAGES OF THE INVENTION
The solenoid valve of the hydraulic unit according to the invention is held in the receiving bore of the hydraulic block with radial play and/or with pivoting play in relation to a longitudinal axis of the receiving bore. As a result, installation errors in the attachment of the solenoid valve in the receiving bore are prevented. The solenoid valve is prevented from pressing against the circumference wall of the receiving bore and also, a material displacement does not take place when there is alternating stress. The size of the radial gap of the solenoid valve in the receiving bore remains permanently limited to a manufacture value at which a sealing cup or another sealing element does not extrude into the radial gap. Assembly tolerances to be maintained are greater and assembly waste due to caulking of the solenoid valve in a position in which it presses against the circumference wall of the receiving bore is virtually eliminated.
In addition, the solenoid valve can have play in the axial direction in the receiving bore.
In a preferred embodiment of the invention, the solenoid valve is secured in the receiving bore by means of a securing ring that is slid onto it, which is affixed, for example, by the caulking of material belonging to the hydraulic block in the mouth region of the receiving bore and which engages an annular shoulder face of the solenoid valve and secures the solenoid valve in the axial direction with a positive fit in the receiving bore, wherein radial play is produced between the securing ring and the solenoid valve.
In one embodiment of the invention, the securing ring has a hollow cylindrical collar, which is plastically deformed into a circumferential groove of the solenoid valve and as a result, enga
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Kirschner Martin
Megerle Friedrich
Schnalzger Guenther
Bastianelli John
Greigg Edwin E.
Greigg Ronald E.
Hepperle Stephen M.
Robert & Bosch GmbH
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