Manual displacement control arrangement for an axial piston pump

Patent metadata

Field	Value
Publication number	US-11268499-B2
Application number	US-201716346209-A
Country	US
Kind code	B2
Filing date	Nov 13, 2017
Priority date	Dec 22, 2016
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

Displacement control device for variably adjusting the displacement of an axial piston hydraulic pump including a rotary shaft rotatable around a shaft axis. A torque can be applied for rotating the rotary shaft to open and close servo pressure lines to adjust the displacement volume of the axial piston hydraulic pump. Concentric to the shaft axis in a mid-portion of the rotary shaft a detent sleeve is positioned having an abutment area onto which, in the neutral position, a sliding element abuts. The detent sleeve, in operating conditions is rotatably fixed with the rotary shaft and turns with the rotary shaft and for neutral position adjustments in non-operating conditions, the detent sleeve and the rotary shaft are detachable from each other such that the rotary shaft can be turned relative and independently within the detent sleeve, which is held in its neutral position by the sliding element.

First claim

What is claimed is:

1. A displacement control device for variably adjusting the displacement volume of a hydraulic axial piston pump comprising a rotary shaft mounted rotatable in a housing around a rotary shaft axis of the rotary shaft, said rotary shaft having a first end and a second end, wherein the rotary shaft is configured to open and close servo pressure lines arranged within the housing when a torque is applied to the second end, which protrudes outside of the housing, wherein the servo pressure lines are configured to conduct hydraulic fluid to and from a servo adjusting unit capable of adjusting the displacement volume of the axial piston pump, said rotary shaft further comprising a mid-portion located between the first end and the second end,
wherein
a detent sleeve is positioned concentric to the rotary shaft axis in the mid-portion of the rotary shaft, the detent sleeve comprising an abutment area onto which, in a neutral position of the displacement control device, a sliding element abuts, the sliding element being mounted pre-stressed in the housing and exerting a resilient force onto the detent sleeve transverse to the rotary shaft axis, wherein the detent sleeve in operating conditions of the displacement control device, is rotatably fixed to the rotary shaft and turns with the rotary shaft, wherein, for neutral position adjustments in non-operating conditions, the detent sleeve and the rotary shaft are detachable from each other, such that the rotary shaft is configured to be turned independently within the detent sleeve which is held in its neutral position by the resilient force of the sliding element onto the abutment area.

2. The displacement control device according to claim 1 , wherein the abutment area is a flattened portion formed on the detent sleeve onto which a flat front face of the sliding element is configured to abut fully-faced in the neutral position of the displacement control device.

3. The displacement control device according to claim 2 , wherein the sliding element and the abutment area are designed such that the detent sleeve is fixed axially with regard to the rotary shaft when the sliding element engages with the detent sleeve.

4. The displacement control device according to claim 2 , wherein the abutment area is a recess formed in the detent sleeve into which a protrusion of the sliding element is configured to be inserted.

5. The displacement control device according to claim 4 , wherein the sliding element and the recess are designed such that the detent sleeve is fixed axially with regard to the rotary shaft when the sliding element engages with detent sleeve.

6. The displacement control device according to claim 1 , wherein the abutment area is a depression into which, in the neutral position of the displacement control device, a convex surface of the sliding element is configured to engage.

7. The displacement control device according to claim 6 , wherein a protrusion of the sliding element engages the detent sleeve laterally and thereby prevents rotational motion of the detent sleeve.

8. The displacement control device according to claim 7 , wherein the sliding element and the depression are designed such that the detent sleeve is fixed axially with regard to the rotary shaft when the sliding element engages with the detent sleeve.

9. The displacement control device according to claim 1 , wherein the abutment area is a recess formed in the detent sleeve into which a protrusion of the sliding element is configured to be inserted.

10. The displacement control device according to claim 4 , wherein the sliding element and the recess are designed such that the detent sleeve is fixed axially with regard to the rotary shaft when the sliding element engages with the detent sleeve.

11. The displacement control device according to claim 1 , wherein a feedback sleeve is attached to the first end of rotary shaft, wherein the feedback sleeve is rotatable with respect to the housing and with respect to the rotary shaft, wherein a feedback element attached to a displacement element of the hydraulic axial piston pump is capable of feeding back the position of the displacement element of the hydraulic axial piston pump and engages with the feedback sleeve eccentrically, such that a motion of the displacement element and therefore of the feedback element causes a rotation of the feedback sleeve relative the rotary shaft, thereby opening and/or closing the servo pressure lines.

12. The displacement control device according to claim 11 , wherein an offset of a feedback element axis to a tilt axis of the displacement element is different from a distance of the feedback element axis to the rotary shaft axis.

13. The displacement control device according to claim 12 , wherein the offset is bigger than the distance.

14. The displacement control device according to claim 1 , wherein an eccentric pin having an eccentric axis is located at the first end of the rotary shaft, wherein the eccentric axis provides a rotational axis for a feedback link, whose first end is coupled to a control spool and whose second end comprises an elongated hole section for receiving a second end of a feedback element attached to a displacement element, such that a motion of the displacement element causes a rotation of the feedback link and shifts the control spool.

15. The displacement control device according to claim 14 , wherein the eccentric pin is integrally formed on the first end of the rotary shaft.

16. The displacement control device according to claim 14 , wherein the elongated hole section is U-shaped.

17. The displacement control device according to claim 14 , wherein the elongated hole section is capable of exerting an elastic force onto the second end of the feedback element for providing a clearance-free engagement of the second end of the feedback element and the elongated hole section.

18. The displacement control device according to claim 1 , wherein the hydraulic axial piston pump is of the swashplate type or the bent axis type, wherein a displacement element of the hydraulic axial piston pump is configured to be swiveled to positive and/or negative displacement angles.

19. The displacement control device according to claim 1 , wherein the torque applied to the second end of the rotary shaft is configured to be generated manually, mechanically, pneumatically, electro-mechanically or hydraulically.

20. The displacement control device according to claim 1 , wherein a lever is fixed to the second end of the rotary shaft or is fixed to the detent sleeve.

Assignees

• Danfoss Power Solutions Gmbh & Co Ohg

Inventors

• Chmatil Miroslav
• Jakubovic Jan
• Chmatil Lubos
• Krissak Peter

Classifications

• F04B1/295 Primary

  by changing the inclination of the swash plate · CPC title

• F04B49/08

  Regulating by delivery pressure · CPC title

• F03C1/0686

  by changing the inclination of the swash plate · CPC title

• F04B1/324

  by changing the inclination of the swash plate · CPC title

• F04B49/002

  Hydraulic systems to change the pump delivery · CPC title