End position detection of a variable hydraulic machine

Patent metadata

Field	Value
Publication number	US-2016282143-A1
Application number	US-201615076964-A
Country	US
Kind code	A1
Filing date	Mar 22, 2016
Priority date	Mar 26, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

The invention relates to a method and a device for determining of at least one end position of a displacement element of an adjustable hydraulic machine, in particular of the axial piston type, shiftable or displaceable between two ends position a by means of a displacement unit between a first end position and a second end position. According to the invention the determination of having reached an end position of displacement takes place by means of a measurement circuit, whose electrical characteristics are changed jumpily when an end position is reached. This is done by connecting a partial branch of the measuring circuit with earth, when a moveable element comes into electric contact with a limit stop assigned to the corresponding end position.

First claim

What is claimed is:

1 . A method for determining of at least one end position of a displacement element of a hydraulic machine displaceable or shiftable between two end positions, the hydraulic machine being variable in its displacement or conveying volume,
wherein an electric contact between the displacement element and an electric component of an electric measuring circuit is established, when the end position is reached by the displacement element and in that the change of electrical parameters of the measuring circuit induced thereby is analyzed for the determination that the end position is reached.

2 . The method according to claim 1 , wherein the electric components comprise a resistance, a capacity or an inductivity.

3 . The method according to claim 1 , wherein one of the captured parameters is the resistance of the measuring circuit or the current flowing in the measuring circuit.

4 . The method according to claim 1 , wherein the measuring circuit is a resonant circuit, whose frequency or amplitude is captured.

5 . A variable hydraulic machine whose displacement or conveying volume is adjustable by means of a displacement unit having a displacement element displaceable between a first end position and a second end position wherein
the hydraulic machine comprises electrical components forming part of an electrical measuring circuit and are assigned to at least one of both end positions, such that an electrical contact between the electrical components arranged in a machine housing of the hydraulic machine and the displacement element can be established, if the displacement element reaches one of the two end positions.

6 . The hydraulic machine according to claim 5 , wherein the displacement element comprises electrical components, which can be brought in contact with the electrical components in the machine housing or with a voltage conducting line of the measuring circuit.

7 . The hydraulic machine according to claim 5 , wherein the hydraulic machine comprises a solenoid, with which the displacement element of the displacement unit is actuable, wherein the solenoid is part of the measuring circuit.

8 . The hydraulic machine according to claim 5 , wherein the hydraulic machine comprises an electronic control unit, by means of which the current through the solenoid can be set and monitored.

9 . The hydraulic machine according to claim 5 , wherein the hydraulic machine comprises at least one adjusting screw for determining one of the two end positions of the displacement element, and that a first contact of an electrical component is arranged isolated from a mechanical contact area of the adjustment screw, wherein the contact area can be contacted electrically conductive by the displacement element when the end position is reached.

10 . The hydraulic machine according to claim 5 , wherein a second contact of the electrical component is connected electrically conductive to the measuring circuit.

11 . The hydraulic machine according to claim 5 , wherein the electric component is a resistor, a condensator or an inductor.

12 . The hydraulic machine according to claim 5 , wherein the electric component is a resistor, which is connected electrically parallel to the solenoid in at least one end position of the displacement element.

13 . The hydraulic machine according to claim 5 , wherein a line, which connects the power source of the measuring circuit with an electrical component, runs via a light emitting electric component, in particular a light emitting diode.

14 . The method according to claim 2 , wherein one of the captured parameters is the resistance of the measuring circuit or the current flowing in the measuring circuit.

15 . The method according to claim 2 , wherein the measuring circuit is a resonant circuit, whose frequency or amplitude is captured.

16 . The hydraulic machine according to claim 6 , wherein the hydraulic machine comprises a solenoid, with which the displacement element of the displacement unit is actuable, wherein the solenoid is part of the measuring circuit.

17 . The hydraulic machine according to claim 6 , wherein the hydraulic machine comprises an electronic control unit, by means of which the current through the solenoid can be set and monitored.

18 . The hydraulic machine according to claim 7 , wherein the hydraulic machine comprises an electronic control unit, by means of which the current through the solenoid can be set and monitored.

19 . The hydraulic machine according to claim 6 , wherein the hydraulic machine comprises at least one adjusting screw for determining one of the two end positions of the displacement element, and that a first contact of an electrical component is arranged isolated from a mechanical contact area of the adjustment screw, wherein the contact area can be contacted electrically conductive by the displacement element when the end position is reached.

20 . The hydraulic machine according to claim 7 , wherein the hydraulic machine comprises at least one adjusting screw for determining one of the two end positions of the displacement element, and that a first contact of an electrical component is arranged isolated from a mechanical contact area of the adjustment screw, wherein the contact area can be contacted electrically conductive by the displacement element when the end position is reached.

Assignees

• Danfoss Power Solutions Gmbh & Co Ohg

Inventors

• Marsch Suenje
• Rathke Rolf
• Kaiser Stephan
• Kaya Edat

Classifications

• F04B1/328

  by changing the inclination of the axis of the cylinder barrel relative to the swash plate · CPC title

• F04B1/2014

  Details or component parts · CPC title

• F04B1/32 Primary

  by varying the relative positions of a swash plate and a cylinder block · CPC title

• F04B49/06

  Control using electricity (regulating by means of floats actuating electric switches F04B49/04) · CPC title

• G01B7/003 Primary

  for measuring position, not involving coordinate determination (coordinate measuring G01B7/004) · CPC title