Fluid handling – Self-proportioning or correlating systems – Self-controlled branched flow systems
Patent
1993-12-17
1995-07-11
Nilson, Robert G.
Fluid handling
Self-proportioning or correlating systems
Self-controlled branched flow systems
1375395, 417304, G05D 701
Patent
active
054311837
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a flow regulator valve, in particular, for positive-displacement pumps used in auxiliary power steering systems in motor vehicles, according to the preamble of claim 1. A flow regulating piston is guided in a sealing manner in a valve borehole. Arranged inside the flow regulator piston is a pressure limiting valve whose closing body is forced against a valve seat by the force of a spring. The spring force can be adjusted by a setting screw.
Such a valve is known from U.S. Pat. No. 3,366,065. In this particular flow regulator valve, the spring force, and thus also the opening pressure of the flow regulator valve, are adjusted by a setting screw. The setting value of the spring force is determined by discs that are inserted between a collar of the setting screw and a front surface of the flow regulator piston. To secure the setting screw against being twisted out, the setting screw must be tightened with a certain torque. The required torque is so great here that the flow regulator piston is deformed. The flow regulator piston can become stuck in the valve borehole due to this deformation of the outside circumferential surface of the flow regulator piston. There must be a relatively great minimum play between the valve borehole and the flow regulator piston to prevent it from getting stuck. This great play leads to a high leakage oil loss between the flow regulator piston and the valve borehole and thus reduces the hydraulic efficiency of the pump. The large leakage oil portion furthermore causes a relatively great hysteresis in connection with the feed flow characteristic.
The task of the invention is to create a flow regulator valve in which the above-mentioned disadvantages are avoided. In particular, the flow regulator piston is not to be deformed when the flow regulator valve is adjusted.
This problem is solved by-the flow regulator valve characterized in claim 1. To provide this solution, in particular, the setting screw is made in the form of a headless pin which--when it is in its adjusted position--is secured with respect to the flow regulator piston by a locknut.
If, in a flow regulator valve according to the invention, the locknut is tightened with a torque that--in terms of its magnitude--corresponds to the torque applied during the adjustment of the known flow regulator valve, then the deformation is distributed over these two parts, depending on the dimensions of the flow regulator piston and the locknut. As a result, the flow regulator piston is deformed considerably less, so that one needs an essentially smaller minimum play between the flow regulator piston and the valve borehole.
Here it is particularly advantageous when the locknut has a smaller cross-section than the flow regulator piston in the area in which the headless pin is screwed in. This makes it possible to have the deformation--which takes place during the fixing of the setting screw--absorbed completely by the locknut. Another advantage is represented by the fact that the opening pressure of the pressure limiting valve can be set phaselessly. This is made possible by the fact that the setting discs between the setting screw and the flow regulator piston are omitted.
The invention will be explained in greater detail below with the help of a practical example illustrated in the drawing. The drawing shows a longitudinal profile through the flow regulator valve according to the invention.
A flow regulator piston 3 is guided in an axially movable and sealing manner in a valve borehole 1 of a valve housing 2. Flow regulator piston 3 is pressed--to the left, in the drawing--against a housing stop 5 by a spring 4. The left front surface 6 of flow regulator piston 3 is impacted by the pressure from a pressure line 7. A working line 8 leads from pressure line 7 to a consumer, not illustrated. A flow regulator choke 9 is arranged in working line 8. The pressure, prevailing behind the flow regulator choke 9, is supplied via an attenuation choke 10 to a chamber 11 that contains spring 4 and that is limited by the r
REFERENCES:
patent: 2395824 (1946-03-01), Herman
patent: 3366065 (1968-01-01), Pace et al.
patent: 3433240 (1969-03-01), Lehmann
patent: 3656870 (1972-04-01), Kusakabe et al.
Nilson Robert G.
Zalkind Albert M.
ZF Friedrichshafen AG.
LandOfFree
Flow regulator valve does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flow regulator valve, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flow regulator valve will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-496960