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EP-4741650-A1 - COMPONENTS FOR SEALING AND SEALING CONCEPT FOR A HYDRAULIC AXIAL PISTON MACHINE

EP4741650A1EP 4741650 A1EP4741650 A1EP 4741650A1EP-4741650-A1

Abstract

The present invention relates to a thrust pad (1) for a port flange (101) of a hydraulic axial piston machine (1000). The thrust pad (1) is provided to improve a sealing concept of hydraulic axial piston machines. In this regard, the thrust pad (1) comprises a top surface (2), a lateral surface (3) and a bottom surface (4). Further, the thrust pad (1) comprises a curved shape configured to be arranged at least partially between the port flange (101) and a port plate (103) of the hydraulic axial piston machine (1000). The thrust pad (1) extends in a first direction (X), a second direction (Y) and a third direction (Z). The second direction (Y) is defined orthogonal with respect to the first direction (X) and the third direction (Z) is defined orthogonal with respect to the first direction (X) and the second direction (Y). Furthermore, the thrust pad (1) extends in the third direction (Z) less than in the first direction (X) and the second direction (Y), wherein the thrust pad (1) extends in the first direction (X) more than in the second direction (Y). The thrust pad (1) comprises a through hole (9), wherein the through hole (9) is configured to fluidically connect a first port (109) of the port flange (101) to a control hole (102) of the port plate (103). In addition, the present invention relates to a port flange, an assembly, and a hydraulic axial piston machine.

Inventors

  • HANSEN, POUL ERIK
  • IVERSEN, FRANK HOLM
  • BABU, ACHUTHAN

Assignees

  • Danfoss A/S

Dates

Publication Date
20260513
Application Date
20241107

Claims (14)

  1. Thrust pad (1) for a port flange (101) of a hydraulic axial piston machine (1000), wherein the thrust pad (1) comprises a top surface (2), a lateral surface (3) and a bottom surface (4), wherein the thrust pad (1) comprises a curved shape configured to be arranged at least partially between the port flange (101) and a port plate (103) of the hydraulic axial piston machine (1000), wherein the thrust pad (1) extends in a first direction (X), a second direction (Y) and a third direction (Z), wherein the second direction (Y) is defined orthogonal with respect to said first direction (X) and the third direction (Z) is defined orthogonal with respect to said first direction (X) and said second direction (Y), wherein the thrust pad (1) extends in the third direction (Z) less than in the first direction (X) and the second direction (Y), wherein the thrust pad (1) extends in the first direction (X) more than in the second direction (Y), wherein the thrust pad (1) comprises a through hole (9), and wherein the through hole (9) is configured to fluidically connect a first port (109) of the port flange (101) to a control hole (102) of the port plate (103).
  2. Thrust pad (1) according to claim 1, wherein the lateral surface (3) is partially provided by an inner curved contour (7) and partially provided by an outer curved contour (8) extending between a first tip portion and a second tip portion, and wherein the inner curved contour (7) and the outer curved contour (8) respectively converge at a first end point (5) and a second end point (6) of the respective tip portions, and/or wherein the thrust pad (1) comprises a semilunar, curved shape.
  3. Thrust pad (1) according to any one of the preceding claims, wherein the through hole (9) extends partially along the curved shape of the thrust pad (1), and wherein the through hole (9) comprises a bigger extension in the first direction (X) than in the second direction (Y).
  4. Thrust pad (1) according to any one of the preceding claims, wherein the through hole (9) is a curved slotted hole.
  5. Thrust pad (1) according to any one of the preceding claims, wherein the thrust pad (1) comprises a thickness defined by an extension of the thrust pad (1) along the third direction (Z), wherein the thickness is at least 10 times smaller than the extension of the thrust pad (1) in the first direction (X).
  6. Port flange (101) for a hydraulic axial piston machine (1000), wherein the port flange (101) extends along a longitudinal axis (XL) between a cylinder drum side surface (105) and an opposite surface (106), wherein the port flange (101) comprises a first port (109) and a second port (110) each of which are configured to fluidically connect the port flange (101) to a cylinder (111) of a cylinder drum (107) of a hydraulic axial piston machine (1000), wherein the cylinder drum side surface (105) of the port flange (101) further comprises a recess (112) at least partially surrounding the first port (109), wherein the recess (112) is configured to at least partially receive the thrust pad (1) according to any one of claims 1 to 5, wherein, when the thrust pad (1) is received in the recess (112) of the port flange (101), the through hole (9) of the thrust pad (1) and the first port (109) at least partially overlap, so that the first port (109), when the port flange (101) is fluidically connected to the cylinder (111) of the cylinder drum (107) of the hydraulic axial piston machine (1000), is fluidically connected by the through hole (9) of the thrust pad (1).
  7. Port flange (101) according to claim 6, wherein the recess (112) comprises a groove (114) which extends orthogonal to the longitudinal axis (XL), wherein the groove (114) is configured to receive a sealing element, and wherein, when the thrust pad (1) is at least partially received within the recess (112), the sealing element is configured to abut the lateral surface (3) of thrust pad (1).
  8. Port flange (101) according to any one of claims 6 or 7, wherein the first port (109) provides a high-pressure port configured to supply fluid comprising high pressure to the cylinder (111) of the cylinder drum (107) of the hydraulic axial piston machine (1000) or to discharge fluid comprising high pressure from the cylinder (111) of the cylinder drum (107) of the hydraulic axial piston machine (1000).
  9. Assembly (100) of a port plate (103), the thrust pad (1) according to any one of claims 1 to 5, and the port flange (101) according to any one of claims 6 to 8, wherein the thrust pad (1) is at least partially received in the recess (112) of the port flange (101) so that the third direction (Z) of the thrust pad (1) runs parallel to the longitudinal axis (XL) of the port flange (101), wherein the cylinder drum side surface (105) of the port flange (101) is arranged in abutment with the port plate (103) and/or the port plate (103) is arranged in abutment with the thrust pad (1) so that the thrust pad (1) is at least partially arranged between the port flange (101) and the port plate (103), when the thrust pad (1) is received in the recess (112).
  10. Assembly (100) according to claim 9, wherein the recess (112) of the port flange (101) forms a step portion having a contact surface (113) offset along the longitudinal axis (XL) with respect to the cylinder drum side surface (105) of the port flange (101), and wherein an offset between the contact surface (113) and the cylinder drum side surface (105) is greater than the extension of the thrust pad (1) along the third direction (Z).
  11. Assembly (100) according to any one of claims 9 or 10, wherein the assembly (100) further comprises a sealing element arranged inside the groove (114) of the recess (112) of the port flange (101).
  12. Hydraulic axial piston machine (1000) comprising an assembly according to any one of claims 9 to 11, a cylinder drum (107) having at least one cylinder (111) with a piston (116), a retainer plate (119) mechanically coupled to the piston (116) of the cylinder drum (107), and a drive shaft (120) mechanically coupled to the cylinder drum (107).
  13. Hydraulic axial piston machine (1000) according to claim 12, wherein the hydraulic axial piston machine (1000) further comprises a pressure plate (108) and at least one spring (120) configured to push the pressure plate (108) against the port plate (103) thereby providing sealing between the port plate (103) and the cylinder drum side surface (105) of the port flange (101).
  14. Hydraulic axial piston machine (1000) according any one of claims 12 or 13, wherein, when the drive shaft (120) is rotated by a drive motor, the hydraulic axial piston machine (1000) is configured to suck low pressure fluid into the at least one cylinder (111) of the cylinder drum (107) via the second port (110) of the port flange (101) and to discharge high pressure fluid via the first port (109) of the port flange (101), and wherein, when the drive shaft (120) is rotated by rotation of the cylinder drum (107), the hydraulic axial piston machine (1000) is configured to supply high pressure fluid to the at least one cylinder (111) of the cylinder drum (107) via the first port (109) of the port flange (101) and to discharge low pressure fluid via the second port (110) of the port flange (101).

Description

The present invention relates to a thrust pad for a port flange of a hydraulic axial piston machine. Further, the present invention relates to a port flange, to an assembly of a port plate, a thrust pad and a port flange as well as to a hydraulic axial piston machine. Hydraulic axial piston machines are well-known in the art. In hydraulic axial piston machines, pistons are guided in cylinders of a cylinder drum and rotate around a drive shaft of the hydraulic axial piston machine. Further, each piston is coupled to a sliding shoe which is retained in a retainer plate, wherein the pistons perform a complete stroke with each revolution of the cylinder drum. The term "hydraulic axial piston machine" refers to a hydraulic axial piston pump and a hydraulic axial piston motor. The hydraulic axial piston pump converts mechanical energy into hydraulic energy, while the hydraulic axial piston motor converts hydraulic energy into mechanical energy. In this respect, hydraulic axial piston machines are thus for example often used in hydraulic systems of construction machinery, agricultural machinery and industrial plants. The excellent reliability, high power density and precise controllability make hydraulic axial piston machines a preferred choice for hydraulic systems. Typically, hydraulic axial piston machines are thus integrated into complex hydraulic fluid systems and fluidically connected to ducts, channels, passages, pipes or the like which transport fluid under high pressure or fluid under low pressure to and from the hydraulic axial piston machine. Leakages in the hydraulic fluid system, especially in a transition area between fluid transportation means and, for example a cylinder drum of the hydraulic axial piston machine may cause energy losses. Consequently, hydraulic axial piston machine known in the art are provided with a sealing concept to allow high-pressure fluid to enter or exit the hydraulic axial piston machine, preferably without leakage, however, typically with limited leakage, which decrease the efficiency of the hydraulic axial piston machine. In other words, leakages during supply and discharge of fluid in the cylinders of the cylinder drum may lead to efficiency losses of the hydraulic axial piston machine. Thus, to prevent excessive leakage, it is known to arrange sealing elements in the hydraulic axial piston machine. However, known sealing concepts often require alternating sealings, i.e. sealing elements or surfaces alternating between the high and low pressure side, have large dimensions, need many parts, are complex, heavy or simply not suitable for high pressures. In particular, handling high pressures that deform sealing surfaces, such as sealing surfaces of a port flange or port plate of a hydraulic axial piston machine, may pose difficulties. Consequently, improved sealing concepts for hydraulic axial piston machines are required. Therefore, it is the object of the present invention to improve the sealing concept of hydraulic axial piston machines. In particular, it is the object of the present invention to provide an improved sealing concept for hydraulic axial piston machines that reduces leakage while for example allowing to operate the system at higher pressures and with higher volume flows. The object is solved by a thrust pad according to claim 1. Further, the object is solved by a port flange according to claim 7, by an assembly according to claim 10 as well as by a hydraulic axial piston machine according to claim 13. Typically, hydraulic axial piston machines comprise a port plate also known as a valve plate, a distributor plate or a control plate. The port plate comprises control holes that allow fluid to flow, for example from a port flange via said port plate into cylinders of a cylinder drum of the hydraulic axial piston machine. The thrust pad according to the invention is for a port flange of a hydraulic axial piston machine and in other words configured to be used with said port flange in order to improve the sealing. The thrust pad comprises a top surface, a bottom surface and a lateral surface. The top surface may be arranged on an opposite side to the bottom surface. When the thrust pad may be arranged in a recess of a port flange, the bottom surface may be facing towards the port flange, wherein the top surface may be facing towards a port plate. The bottom surface may comprise first apertures which may align with second apertures of the port flange, when the thrust pad is arranged in the recess of the port flange. In one aspect, the thrust pad comprises two apertures, one at each tip portion of the thrust pad. The first apertures and the second apertures may be provided by blind holes. Resilient elements, for example spring elements, may be arranged inside the first and second apertures in order to push the thrust pad towards the port plate. Further, the top surface may be a substantially flat surface and may at least partially be in abutment with the port plat