Tandem axial piston pump with shared cylinder block

Patent metadata

Field	Value
Publication number	US-2016131118-A1
Application number	US-201414534483-A
Country	US
Kind code	A1
Filing date	Nov 6, 2014
Priority date	Nov 6, 2014
Publication date	May 12, 2016
Grant date	—

Abstract

A tandem axial piston pump having a common cylinder block. A first axial piston pump includes a first set of pistons arranged in a parallel, circular array and configured to reciprocate in response to rotation about a central axis. A second axial piston pump includes a second set of pistons arranged in a parallel, circular array and configured to reciprocate as they rotate about the central axis. A common drive shaft extends along the central axis, both the first and second sets of pistons being configured to rotate with the common drive shaft. Both the first and second sets of pistons are configured to reciprocate within corresponding separate first and second sets of cylinder bores of the common cylinder block.

First claim

What is claimed is:

1 . A tandem axial piston pump comprising:
a first axial piston pump including a first set of pistons arranged in a parallel, circular array and configured to reciprocate in response to rotation about a central axis; a second axial piston pump including a second set of pistons arranged in a parallel, circular array and configured to reciprocate as they rotate about the central axis; and a common drive shaft extending along the central axis, wherein both the first and second sets of pistons are configured to rotate with the common drive shaft; wherein both the first and second sets of pistons are configured to reciprocate within corresponding separate first and second sets of cylinder bores of a common cylinder block.

2 . The tandem axial piston pump of claim 1 , wherein the corresponding sets of cylinder bores include a first set of cylinder bores extending from a first axial end of the cylinder block and a second set of cylinder bores extending from a second axial end of the cylinder block.

3 . The tandem axial piston pump of claim 2 , further comprising
a first swash plate coupled to a base end of each of the pistons of the first set, the first swash plate defining a cam angle with respect to the central axis, the cam angle defining a stoke distance through which each of the pistons of the first set travels back-and-forth upon a rotation about the central axis; and a second swash plate coupled to a base end of each of the pistons of the second set, the second swash plate defining a cam angle with respect to the central axis, the cam angle defining a stoke distance through which each of the pistons of the second set travels back-and-forth upon a rotation about the central axis.

4 . The tandem axial piston pump of claim 1 , wherein the cylinder block has an outer cylindrical surface including a respective radial port corresponding to and establishing fluid communication with each of the cylinder bores of the first and second sets through a side wall of each corresponding cylinder bore, wherein all of the radial ports corresponding to the cylinder bores of the first set are arranged at a first axial position, and all of the radial ports corresponding to the cylinder bores of the second set are arranged at a second axial position.

5 . The tandem axial piston pump of claim 1 , further comprising at least one distribution ring positioned around the cylinder block and having
a first inlet slot at the first axial position, a first outlet slot at the first axial position and offset circumferentially from the first inlet slot, a second inlet slot at the second axial position, and a second outlet slot at the second axial position and offset circumferentially from the second inlet slot.

6 . The tandem axial piston pump of claim 5 , further comprising a port block having a bore receiving the at least one distribution ring, the port block configured to direct a fluid supply flow to the first and second axial piston pumps via the first and second inlet slots and to receive a pumped fluid flow from the first and second axial piston pumps via the first and second outlet slots.

7 . The tandem axial piston pump of claim 6 , wherein the at least one distribution ring is press-fit into the bore of the port block with the first and second inlet slots in fluid communication with at least one inlet port of the port block, and the first and second outlet slots in fluid communication with at least one outlet port of the port block.

8 . The tandem axial piston pump of claim 7 , wherein the port block includes separate inlet ports and separate outlet ports for each of the first and second inlet slots and each of the first and second outlet slots.

9 . The tandem axial piston pump of claim 5 , wherein the first inlet slot and the first outlet slot are formed in a first distribution ring, and the second inlet slot and the second outlet slot are formed in a separate second distribution ring.

10 . The tandem axial piston pump of claim 1 , wherein the cylinder block is integrally formed as a single, monolithic piece.

11 . A tandem axial piston pump comprising:
a drive shaft defining an axis; a first set of pistons arranged in parallel with the axis in a circular array and rotatable about the axis by the drive shaft; a second set of pistons arranged in parallel with the axis in a circular array and rotatable about the axis by the drive shaft; a first swash plate coupled to a base end of each of the pistons of the first set, the first swash plate defining a cam angle with respect to the axis, the cam angle defining a stoke distance through which each of the pistons of the first set travels back-and-forth upon a rotation about the axis; a second swash plate coupled to a base end of each of the pistons of the second set, the second swash plate defining a cam angle with respect to the axis, the cam angle defining a stoke distance through which each of the pistons of the second set travels back-and-forth upon a rotation about the axis; and a cylinder block having a first set of cylinder bores receiving the first set of pistons from a first end of the cylinder block and a second set of cylinder bores receiving the second set of pistons from a second end of the cylinder block opposite the first end.

12 . The tandem axial piston pump of claim 11 , wherein the first and second swash plates are operable to vary the respective cam angles independently of each other such that the first set of pistons along with the first set of cylinder bores define a first axial piston pump having a displacement variable independently of a second axial piston pump defined by the second set of pistons along with the second set of cylinder bores.

13 . The tandem axial piston pump of claim 11 , wherein the cylinder block has an outer cylindrical surface including a respective radial port corresponding to and establishing fluid communication with each of the cylinder bores of the first and second sets through a side wall of each corresponding cylinder bore, wherein all of the radial ports corresponding to the cylinder bores of the first set are arranged at a first axial position, and all of the radial ports corresponding to the cylinder bores of the second set are arranged at a second axial position.

14 . The tandem axial piston pump of claim 11 , further comprising at least one distribution ring positioned around the cylinder block and having
a first inlet slot at the first axial position, a first outlet slot at the first axial position and offset circumferentially from the first inlet slot, a second inlet slot at the second axial position, and a second outlet slot at the second axial position and offset circumferentially from the second inlet slot.

15 . The tandem axial piston pump of claim 14 , further comprising a port block having a bore receiving the at least one distribution ring, the port block configured to direct a fluid supply flow to the first and second axial piston pumps via the first and second inlet slots and to receive a pumped fluid flow from the first and second axial piston pumps via the first and second outlet slots.

16 . The tandem axial piston pump of claim 15 , wherein the at least one distribution ring is press-fit into the bore of the port block with the first and second inlet slots in fluid communication with at least one inlet port of the port block, and the first and second outlet slots in fluid communication with at least one outlet port of the port block.

17 . The tandem axial piston pump of claim 16 , wherein the port block includes separate

Assignees

• Bosch Gmbh Robert

Inventors

• Weathersbee Michael
• Kalocy Richard
• Stewart Jonathan

Classifications

• F04B1/2078 Primary

  Swash plates · CPC title

• F04B1/2064

  Housings · CPC title

• F04B1/20 Primary

  having rotary cylinder block · CPC title

• F04B1/32

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

• F04B1/22

  having two or more sets of cylinders or pistons · CPC title