Electromagnetically actuated valve, in particular for slip-contr

Details Electromagnetically actuated valve, in particular for slip-contr Electromagnetically actuated valve, in particular for slip-contr

1996-03-25

1998-03-10

Oberleitner, Robert J.

Fluid-pressure and analogous brake systems

Speed-controlled

Having a valve system responsive to a wheel lock signal

251 83, 25112902, 137529, 1376275, B60T 836

Patent

active

057252890

DESCRIPTION:

BRIEF SUMMARY
RELATED PATENT APPLICATION

This application is copending with application Ser. No. 08/483,418 filed Jun. 7, 1995, which has similar features in a valve.


PRIOR ART

The invention is based on an electromagnetically actuated valve, in particular for slip-controlled hydraulic brake systems in motor vehicles.
Such a valve is known from DE 39 34 771 C1, FIG. 3. It has a control piston which is arranged in the valve dome, forms a stop for the magnet armature and is guided so that it can be displaced longitudinally on a pin which starts from the valve body and penetrates the magnet armature. The end of the control piston facing away from the armature bounds a control chamber which is in connection with the pressure medium inlet of the known valve by means of a pressure medium passage penetrating the pin and the control piston on the same axis. While the pressures are balanced on the two end surfaces of the magnet armature, pressure fed into the control chamber can displace the control piston axially against a stop. This reduces the stroke of the magnet armature by a predetermined amount and, in consequence, throttles the flow cross section.
This mode of operation of the known valve can be used in slip-controlled hydraulic brake systems in which the pressure medium inlet is in connection with the main brake cylinder and the pressure medium outlet is in connection with the wheel brake cylinder. If, for example, the valve is switched into its closed position by excitation of the magnet coil during brake slip control and, during the reduction of the pressure in the wheel brake cylinder, it generates a sufficiently large pressure drop between the pressure medium inlet and the pressure medium outlet, this causes the displacement of the control piston, as described above, with the result that when the valve is opened, the throttling, already mentioned, of the flow cross section becomes effective as long as the pressure difference between the inlet and the outlet exists. Because of the reduced gradient in the case of a build-up of pressure following a reduction of pressure in brake slip control, the reduction in the flow cross section has a favorable effect on the control quality and the noise behavior of the brake system. During a normal braking operation without danger of wheel lock, on the other hand, the full flow cross section of the valve is available and this supports a desirably short brake system response time when the brakes are actuated.
In the known valve, however, the fixed setting of the throttled flow cross section is disadvantageous because this subjects the flow quantity to fluctuations which depend on the differential pressure. In addition, the flow quantity is quite substantially dependent on the absolute dimension of the flow cross section, i.e. the stop requires very tight tolerancing. Because of the control piston necessary, furthermore, the valve is relatively costly.


ADVANTAGES OF THE INVENTION

The valve in accordance the invention with has, in contrast, the advantage that, when the second seat valve is closed, the flow cross section of the first seat valve adjusts automatically to substantially constant flow quantities, which are lower than those for the fully opened first seat valve, as a function of the forces acting on the armature, but without any magnetic force, when there is a sufficiently large pressure drop between the inlet and outlet ends of the valve. The structural outlay necessary to achieve this mode of operation, as a flow regulating valve, by the valve according to the invention is small.
Advantageous further developments and improvements to the valve are possible by means of the measures listed hereinafter.
Configuring the second valve on the components necessary in any case is particularly advantageous with respect to costs and functional reliability.
The sealed guidance of the magnet armature in the valve dome is also of advantage because this creates, in a simple manner, a separation in terms of pressure between the two end surfaces of the armature in order to generate a

REFERENCES:
patent: 3829060 (1974-08-01), Von Lewis
patent: 4526203 (1985-07-01), Leiber
patent: 5076538 (1991-12-01), Mohr et al.
patent: 5167442 (1992-12-01), Alaze et al.
patent: 5318066 (1994-06-01), Burgdorf et al.
patent: 5370450 (1994-12-01), Volz et al.
patent: 5476243 (1995-12-01), Oehler et al.

Affiliated with

Also associated with

Rating

Electromagnetically actuated valve, in particular for slip-contr does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Electromagnetically actuated valve, in particular for slip-contr, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electromagnetically actuated valve, in particular for slip-contr will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-133516