Device for controlling brake pressure

#The present invention generally relates to vehicle brakes and more particularly relates to a brake pressure control device for anti-lock pressure control and for automatic brake intervention.

#DE 42 32 311 C1 discloses a hydraulic automotive vehicle brake system with an anti-lock device which, for improvement of the vehicle tracking stability, is equipped with an automatic brake intervention device for driving dynamics control. Special measures are required to be taken both for driving dynamics control and for traction slip control in order to provide the pressure fluid necessary for brake intervention by means of a pump at a sufficient rapidity. One of these measures is, among others, the arrangement of a pressure sensor at the pressure fluid path extending from the brake pressure generator in order to sense the pilot pressure that is respectively generated by the driver in the brake pressure generator.

#One constructive design variation for arranging a pressure sensor at a special precharging device for an automotive vehicle brake system is shown on page 687 of the ATZ Journal, 96th volume/no. 11. The arrangement of the pressure sensor at the housing of the so-called charging piston unit normally necessitates a complicated cable connection with the control and regulating electronics.

#FIG. 1 is a partial cross-sectional view of a brake pressure control device in the area of a first suggested point of connection for a pressure sensor at a lateral housing surface.

#FIG. 2 is a top view of the brake pressure control device according to FIG. 1 on the cross-sectional plane BB of the housing block indicated in FIG. 1.

#FIG. 3 is a top view of the end surface of the housing of the brake pressure control device with an arrangement of the pressure sensor between the valve rows.

#FIG. 1 shows a considerably enlarged view of a brake pressure control device for a hydraulic automotive vehicle brake system that is connected to a brake pressure generator which, by way of pressure modulation valves 4 inserted into the brake pressure control device, is hydraulically connected to several wheel brakes and a pressure fluid accumulator system. The latter system is connected to a suction side of a motor-driven pump 14 having a pressure side which is connected to the brake pressure generator. Both the pump 14 and the pressure fluid accumulator system are integrated in the brake pressure control device. The pump 14 integrated in the block-shaped housing 2 between the rows of the pressure modulation valves 4 is with its pressure side in connection to a pressure fluid conduit 5 which extends from the brake pressure generator to the wheel brakes. Conduit 5 leads to the pressure modulation valves 4 in the housing 2 and to a pressure sensor 7 which is interconnected in terms of circuitry between the brake pressure generator and the pressure modulation valves 4 at the pressure fluid conduit 5. The pressure sensor 7 is fitted at a pressure sensor connecting port 1 directed into the housing 2, which port extends from the end surface of the housing 2 and opens into the pressure fluid conduit 5. The pressure sensor connecting port 1 is disposed between the accommodating bores 3 which are directed into the housing 2 and provided for the pressure modulation valves 4. One of the pressure modulation valves 4 is also shown in a cross-section in the foreground of the housing area with the pressure sensor 7. It is proposed in FIG. 1 of the present embodiment to introduce the pressure sensor connecting port 1 transversely into the housing 2 and, thus, preferably at right angles to the accommodating bore 3 for the pressure modulation valve 4, as shown in the cross-sectional view. The pressure sensor connecting port 1 opens directly into the pressure fluid conduit 5 on the housing side which enters the housing 2 between the illustrated accommodating bore 3 and another accommodating bore 3 positioned behind in a valve row. Attached in the pressure sensor connecting port 1 is a substantially sleeve-shaped adapter 6 by means of self-shearing engagement, the said adapter carrying the pressure sensor 7 at its extension projecting from the pressure sensor connecting port 1. The pressure sensor 7 is operatively secured by means of a screw coupling on the sleeve-shaped portion of the adapter 6 that projects from the pressure sensor connecting port 1. To align the pressure sensor 7 and the adapter 6 on the housing 2, an adjustment means 8 in the shape of a hexagonal outer contour on the adapter and a hexagonal recess on the housing is fitted in the present embodiment, positioning the pressure sensor 7 with its electrical connection 9 in a desired position of direction of rotation with respect to the cover 10 seated on the housing 2. To this end, the pressure sensor 7 includes an annular housing portion which embraces the adapter 6 and adjacent to which is the cylindrical sensor housing which accommodates the sensor element and the electric and/or electronic components of the pressure sensor 7. Thus, pressure sensor 7 forms an independently operable subassembly for the straightforward attachment on the housing 2 and for the reliable electrical contacting of the electronic controller fitted in the cover 7, of which one electronic component is symbolically shown. In the present embodiment according to FIG. 1, the additional function of the hexagonal outer contour provided on the adapter 6 is to take up the torque produced when screwing the nut 16 onto the threaded portion on the adapter 6 that projects from the sensor housing, and the hexagonal outer contour can be calked additionally after press-fitting the adapter 6 into the pressure sensor connecting port 1 in order to relieve the press fit from load in the self-calking area due to the high hydraulic pressures. The sensor housing is conformed to the adapter 6 in the area of the hexagonal outer contour, to which end a hexagonal recess is provided on the annular housing portion of the pressure sensor 7, thereby ensuring a simple alignment for the electrical connection to the electronic controller already when the pressure sensor 7 is slipped onto the adapter 6. Another advantage of the arrangement of the pressure sensor 7 according to the drawing involves that after the drilling operation of the housing 2, a plug or a closure ball is not necessary due to the arrangement of the pressure sensor connecting port 1 at this location. Due to the fact that the pressure sensor 7 is fitted to the lateral surface of the housing 2 according to the principle of a sparkplug, the total brake pressure control device will not be considerably enlarged in size. The consequence is that the electrical connection 9 of the pressure sensor 7 in the capacity of a sparkplug, by means of a simple rigid electrical plug connection, engages directly into the matching plug on the lateral surface of the cover 10 which is connected to the electric or electronic components 11 inside the cover 10.

#The adjustment means 8 described hereinabove may be omitted under certain circumstances in the event that the electrical connection 9 to the controller is effected by way of flexible cable strands. O-rings 17 are arranged on either side of the pressure measuring points 16 on the sleeve portion in order to seal the pressure sensor 7 on the adapter 6.

#The arrangement and constructive design of one of the pressure modulation valves 4 may further be taken from FIG. 1 and will be illustrated in greater detail by way of FIG. 5 hereinbelow.