US 2003/0113216 A1Published application

Control device for positive displacement pumps

AssigneeZF Lenksysteme GmbH

InventorsGunter Draskovits, Gerhard Zimmermann

Life of this patent

Estimating the term…

Loading patent…

Abstract

A control device for a positive displacement pump includes a throttle device and a flow control valve. The flow control valve includes a flow control piston and is configured to regulate an unrequired excess flow of the pump at an increased speed. The throttle device is configured to produce a speed-related pressure differential in a bore section, the pressure differential being responsible for the displacement of the flow control valve and the throttle device. The throttle device is arranged in the pressure outlet (bore section) of the pump and includes a regulating pin connected to the flow control piston, having a control contour configured so that a modifiable through cross-section is created in association with a throttle bore. The control pin has a wider section in an axial displacement area of the throttle device, the area not being involved in control of the volume flow, whereby a minimum obturating section arises in the displacement area. This may result in accelerated movement of the flow control piston, which may result in quicker reaction of the control mechanism, thereby preventing an overshoot and overincrease in the flow capacity.

Claims4

Dependent claims

A control device for positive displacement pumps, in particular vane cell pumps, with the following features:

a pressure space (12) of the pump is connected via a throttle device (20) to an outlet (41) connected to a consumer;
a first end face (33) of a flow control piston (21), which is displaceable in a housing bore (17), is connected to the pressure space (12);
a second end face (42) of the flow control piston (21) delimits a space (36) which is connected to the outlet (41)
depending on a differential pressure acting on the two end faces, the flow control piston (21) opens a connection from the pressure space (12) to an inlet duct (23) of the pump,
the throttle device (20) is located in the pressure output (bore portion 17A) of the pump and comprises a control pin (27), the control contour of which is designed in such a manner that, together with a throttling bore (28), a modifiable passage cross section is brought about, one of the two elements, control pin (27) and throttling bore (28), being connected to the flow control piston (21), and the other of the two elements being fixed in relation to the housing,
characterized in that, in an axial displacement region of the throttle device (20), which region, at the flow control piston (21), is not yet used for volume flow control, the control pin (27) has a thickened portion, so that a minimal aperture cross section exists in this displacement region.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/203,357Filed 15 Oct 2002
Priority: DE 100 06 140.011 Feb 2000
Published: 19 Jun 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

F04C 15/062
Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet: arrangements for supercharging…
F04C 14/26
Characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves: using bypass channels
F04C 15/00
Component parts, details or accessories of machines, pumps or pumping installations, not
F04C
Rotary-piston, or oscillating-piston, positive-displacement machines for liquids