Positive displacement pump including an unloading device

Patent metadata

Field	Value
Publication number	US-11473574-B2
Application number	US-202117317132-A
Country	US
Kind code	B2
Filing date	May 11, 2021
Priority date	Apr 27, 2016
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

A fluid transfer pump that has a housing, a body portion movable within the housing between a first position and a second position, a gear coupled to the housing, a body cavity defined partially between the body portion and the housing, and an aperture defined in the housing that selectively provides a fluid to the body cavity. When the fluid is applied to the body cavity at or above a pilot pressure, the body portion is in the first position adjacent to the gear and when the fluid is applied to the body cavity at a fluid pressure lower than the pilot pressure, the body portion is in the second position and spaced from the gear.

First claim

The invention claimed is:

1. A fluid transfer pump comprising:
a housing defining a cavity and a passage having an inlet disposed at an external portion of the housing;
a movable member disposed within the cavity, the movable member defining a first chamber, wherein a volume of the first chamber is adjustable with movement of the movable member;
a gear set disposed at the first chamber, the gear set including a first gear and a second gear, wherein the first chamber is defined by ends of the first gear, the second gear, and the movable member, the first chamber being configured to hold a first volume of fluid in fluid communication with the ends of the first gear and the second gear; and
a bias element disposed at the movable member, wherein the bias element is configured to adjust the location of the movable member to a first position defining the first volume of the first chamber and to a second position defining a second volume of the first chamber;
wherein the movable member partially defines a second chamber in which a volume of the second chamber is adjustable with movement of the movable member, and the passage is configured to direct a pilot fluid from the inlet to the second chamber to adjust a size of the second chamber from a first size to a second size;
further wherein, a first fluid pressure in the first chamber is greater than a second fluid pressure in the first chamber and the second fluid pressure is insufficient to provide a working pressure.

2. The fluid transfer pump of claim 1 , wherein the housing includes a first cover disposed at a side of the housing and the bias element is disposed between the movable member and the first cover of the housing.

3. The fluid transfer pump of claim 1 further comprising a seal disposed between the first chamber and the second chamber, wherein the seal isolates fluid in the first chamber from fluid in the second chamber.

4. The fluid transfer pump of claim 1 wherein the housing includes an interior wall and the bias element is disposed between the interior wall and the moveable member.

5. A fluid transfer pump comprising:
a housing defining a first cavity and a passage operatively coupled to a second cavity, the passage configured to provide fluid transfer into the second cavity, wherein the housing further includes an interior wall disposed in the housing and a fixed side wall disposed at an end of the housing;
a movable member movably disposed within the housing;
a bias element disposed between the fixed side wall and the movable member, wherein a fluid applied to the passage into the second cavity changes the bias force of the bias element and the location of the movable member with respect to the interior wall to change a volume of the first cavity;
a gear disposed at the first cavity, wherein the volume of the first cavity is configured to provide a fluid pressure within the first cavity to enable the fluid transfer pump to transfer fluid at a working pressure;
a spindle coupled to the gear, wherein the gear partially defines the interior wall, and the spindle extends through both the gear and the movable member; and
a fixed second sidewall, a second sidewall bearing located at the fixed second sidewall, and movable member bearing located at the movable member;
wherein the movable member defines with the housing the first cavity and the second cavity, wherein an increase in volume of the second cavity increases the volume of the first cavity;
further wherein, the spindle extends from the second sidewall bearing to the movable member bearing.

6. The fluid transfer pump of claim 5 , further comprising a seal disposed between the housing and the movable member, wherein the seal substantially prevents fluid located in the second cavity from moving to the first cavity.

7. The fluid transfer pump of claim 6 wherein the bias element is configured to move the movable member toward the gear, and the application of a fluid to the second cavity is configured to move the movable member away from the gear and to compress the bias element, thereby increasing the size of the first cavity.

8. A fluid transfer pump comprising:
a housing defining a first cavity and a passage operatively coupled to a second cavity, the passage configured to provide fluid transfer into the second cavity, wherein the housing further includes a fixed side wall disposed at an end of the housing;
a movable member movably disposed within the housing;
a bias element disposed between the fixed side wall and the movable member, wherein a fluid applied to the passage into the second cavity compresses the bias element and changes the location of the movable member with respect to the fixed side wall to change a volume of the first cavity;
a gear disposed at the first cavity and coupled to a spindle; and
a fixed second sidewall, a second sidewall bearing located at the fixed second sidewall, and a movable member bearing located at the movable member;
wherein the movable member defines with the housing the first cavity and the second cavity, wherein an increase in volume of the second cavity increases the volume of the first cavity;
further wherein, the spindle extends from the second sidewall bearing to the movable member bearing.

9. The fluid transfer pump of claim 8 , further comprising a seal disposed between the housing and the movable member, wherein the seal substantially prevents fluid located in the second cavity from moving to the first cavity.

10. The fluid transfer pump of claim 8 , wherein the bias element applies a biasing force to the movable member toward the gear, and the application of a fluid at a pilot pressure to the second cavity moves the movable member away from the gear and compresses the bias element, thereby increasing the size of the first cavity.

11. A fluid transfer pump comprising:
a housing including a casing and an end cover connected to the casing;
a gear set disposed in the housing;
an end plate movable with respect to the housing and disposed between the gear set and the end cover, the end plate movable between a first position and second position, wherein in the first position the end plate defines a space between the end plate and the end cover and in the second position the end plate defines a first cavity between the gear set and the end plate, wherein the end plate is sealed with the gear set to define the first cavity;
an aperture disposed in the housing and fluidly coupled to the end plate, wherein pilot fluid provided at the aperture moves the end plate between the first position and the second position to provide a working pressure for operation of the fluid transfer pump;
a bias element disposed at the end plate, wherein the bias element is configured to adjust the location of the end plate with respect to the end cover; and
wherein the bias element includes a first bias element and a second bias element, and wherein the first bias element and the second bias element force the end plate away from the end cover in the absence of pilot fluid provided at the aperture.

12. The fluid transfer pump of claim 11 wherein the end plate includes a first aperture and the first bias element is located in the first aperture.

13. The fluid transfer pump of claim 12 wherein the end plate includes a second aperture and the second bias element is located in the second aperture.

14. A fluid transfer pump comprising:
a housing including a casing and an end cover connected to the casing;
a gear set disposed in the housing, the gear set including a first gear and a second gear;
an end plate movable with respect to the housing and disposed between the gear set and the en

Assignees

• Deere & Co

Inventors

• Emmert Robert C
• Butts Thomas W

Classifications

• F04C15/0026

  Elements specially adapted for sealing of the lateral faces of intermeshing-engagement type machines or pumps, e.g. gear machines or pumps · CPC title

• F04C2/14 Primary

  with toothed rotary pistons · CPC title

• F04C14/18

  characterised by varying the volume of the working chamber (by changing the positions of inlet or outlet openings F04C14/10) · CPC title

• F04C14/265

  being obtained by displacing a lateral sealing face · CPC title

• F15B2211/20553

  with pilot circuit, e.g. for controlling a swash plate · CPC title