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DE-102024132736-A1 - Radial piston compressor, mounting sleeve, and method for assembling a piston assembly

DE102024132736A1DE 102024132736 A1DE102024132736 A1DE 102024132736A1DE-102024132736-A1

Abstract

The present invention relates to a radial piston compressor comprising a compressor unit (1) and a drive device (2) for driving the compressor unit, wherein the compressor unit (1) comprises a plurality of piston-working chamber combinations (13) arranged radially around an eccentric shaft (11, 12) with an axis of rotation (D), wherein the piston-working chamber combination (13) comprises a working chamber (131) and a piston (132) displaceable therein, wherein the piston (132) comprises a piston ring (134) which is received in a circumferential piston ring groove (1321) of the piston, wherein the piston ring (134') is provided with at least one chamfer (1341) on its outer circumference. Furthermore, the invention relates to a mounting sleeve with a negative geometry, as well as a method for mounting a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor.

Inventors

  • Ulf Müller
  • Robert Reichelt

Assignees

  • THYSSENKRUPP AG
  • THYSSENKRUPP DYNAMIC COMPONENTS GMBH

Dates

Publication Date
20260513
Application Date
20241108

Claims (14)

  1. Radial piston compressor comprising a compressor unit (1) and a drive device (2) for driving the compressor unit, wherein the compressor unit (1) comprises a plurality of piston-working chamber combinations (13) arranged radially around an eccentric shaft (11, 12) with an axis of rotation (D), wherein the piston-working chamber combination (13) comprises a working chamber (131) and a piston (132) displaceable therein, wherein the piston (132) comprises a piston ring (134) received in a circumferential piston ring groove (1321) of the piston, characterized in that the piston ring (134') is provided with at least one chamfer (1341) on its outer circumference.
  2. radial piston compressor according to Claim 1 , characterized in that the at least one chamfer (1341) is designed as a chamfer on a circumferential outer edge of the piston ring (134').
  3. Radial piston compressor according to at least one of the preceding claims, characterized in that the piston ring (134') is equipped with two chamfers (1341, 1342) which are each provided on the two circumferential outer edges of the piston ring (134').
  4. Radial piston compressor according to at least one of the preceding claims, characterized in that the piston ring (134') is designed as a closed or slotted piston ring, in particular with variation of the slot/butt geometry.
  5. Radial piston compressor according to at least one of the preceding claims, characterized in that the working chamber (131) is equipped with at least one milling pocket (B, C), wherein the height (H) of the piston ring (134') is greater than the maximum milling pocket depth (h).
  6. Radial piston compressor according to at least one of the preceding claims, characterized in that the piston ring (134') is designed as a piston ring made of polytetrafluoroethylene (PTFE), in particular as a non-slotted PTFE ring.
  7. Mounting sleeve for mounting a piston assembly into the working chamber of a radial piston compressor according to at least one of the preceding claims, wherein the working chamber (131) comprises a cylinder wall (Z), characterized in that the mounting sleeve (M) is equipped with at least one negative geometry (1b, 1c).
  8. Mounting sleeve according to Claim 7 , characterized in that the negative geometry (1b, 1c) is designed as the inverse geometry of milling pockets (B, C) of the cylinder wall (Z).
  9. Mounting sleeve according to Claim 8 , characterized in that the milling pockets (B, C) are designed as steps, shoulders, recesses or the like, which form an edge to or in the cylinder wall (Z).
  10. Method for assembling a piston assembly comprising a piston (132) with a piston ring (134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims, characterized in that the piston ring (134') is pre-assembled onto the piston (132) to be inserted into the working chamber (131), wherein the piston (132) with piston ring (134') is inserted into the working chamber (131) as a piston assembly.
  11. Procedure according to Claim 10 , characterized in that the piston assembly (132, 134') is inserted into the working space (131) from the outside in or from the inside out.
  12. Method for assembling a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims or the preamble of the Claim 1 , characterized in that the working chamber (131) is equipped with at least one milling pocket (B, C), wherein the milling pocket (B, C) has a milling pocket depth (h) measured from the cylinder head surface (A), wherein the piston ring (134 or 134') has a height (H), wherein the height (H) of the piston ring (134 or 134') is greater than the maximum milling pocket depth (h), wherein the piston ring (134') is guided through a mounting sleeve (M) until it enters the working chamber (131) below a critical edge of the at least one milling pocket (B, C).
  13. Method for assembling a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims or the preamble of the Claim 1 , characterized in that the working chamber (131) is equipped with at least one milling pocket (B, C), in particular with more than one milling pocket, wherein a mounting sleeve (M) is provided for inserting the piston assembly (132, 134'), which at least in sections exhibits a negative geometry to the arrangement of the milling pockets (B, C) in the working space (131).
  14. Method for assembling a piston assembly comprising a piston (132) with a piston ring (134 or 134') in a working chamber (131) of a radial piston compressor according to at least one of the preceding claims or the preamble of the Claim 1 , characterized in that the working space (131) is equipped with at least one milling pocket (B, C), in particular with more than one milling pocket, wherein a mounting sleeve (M) is provided for inserting the piston assembly (132, 134') which has two protruding geometries (1b and 1c) on the side facing the compressor housing (16), which dip into recesses in the cylinder housing and thus extend the guide for the piston ring 134' at the critical points of the piston ring assembly.

Description

The present invention relates to a radial piston compressor according to the preamble of claim 1, a mounting sleeve according to the preamble of claim 7, and a method for mounting a piston assembly according to claims 10, 12, 13 and 14. A radial piston compressor is a component of fluid power technology. In contrast to an axial piston compressor, in this type of compressor at least one piston-working chamber combination is arranged radially and perpendicular to the drive shaft. A radial piston compressor can also be referred to as a compressor based on the radial piston principle. The piston's conveying or reciprocating motion is usually generated by an eccentric. Therefore, the drive shaft with the eccentric can also be referred to as an eccentric shaft. A radial piston compressor typically comprises several piston-working chamber combinations radiating outwards from the eccentric shaft in a star-shaped pattern. A piston-working chamber combination essentially comprises a working chamber, also called a cylinder, and a piston that moves up and down within the working chamber. The piston has a central geometric axis that coincides with the piston's direction of movement. In a radial piston compressor with an eccentric shaft, the piston has a contact surface on the side facing the eccentric shaft. During the rotation of the eccentric shaft, the eccentric disk contacts or rests against this surface. The eccentric shaft has an axis of rotation around which it rotates. When the eccentric disk contacts the contact surface, the piston moves upward, compressing the medium in the working chamber. Radial piston compressors are used, for example, to compress refrigerant in the air conditioning systems of motor vehicles, especially in electric vehicles. A refrigerant such as CO2 can be used as the medium to be compressed. However, other media and refrigerants are also conceivable. A radial piston compressor of the aforementioned type is, for example, made from the DE 10 2020 211 680 A1 or from the patent application that was unpublished at the time of this application DE 10 2022 133 723 A1 The applicant became aware of this. Typically, the pistons are sealed to the cylinder wall of the cylinder housing by a piston ring positioned within the piston. The piston ring improves the sealing function and thus the efficiency of the compression and therefore of the entire compressor. The working chamber(s) of a radial piston compressor are typically equipped with or interrupted by milled pockets. This means that, as assembly progresses, the piston ring is at risk of shearing off at the edges of these milled pockets. This problem is exacerbated by the fact that, due to functional requirements, the piston ring's outer diameter is usually larger than the piston diameter. The present invention addresses this issue and aims to propose a radial piston compressor that is easy to assemble. In particular, a radial piston compressor is proposed whose pistons can be mounted in the working chambers, thereby minimizing the risk of piston ring shearing during assembly. According to the invention, this problem is solved by a radial piston compressor with the characterizing features of claim 1. By providing the piston ring with at least one chamfer on its outer circumference, the risk of shearing during assembly can be minimized. In other words, a fundamental aspect of the invention is to provide a chamfer on at least one side of the piston ring's outer surface to prevent damage to the critical edges when the piston ring is inserted into the working space. Further advantageous embodiments of the proposed invention arise in particular from the features of the dependent claims. The subject matter or features of the various claims can, in principle, be combined with one another in any way. In an advantageous embodiment of the invention, the at least one chamfer can be configured as a chamfer on a circumferential outer edge of the piston ring. The originally, usually right-angled, edge of the piston ring is accordingly replaced by a chamfer. This results in the desired chamfer, which can counteract shearing of the piston ring when the piston is inserted into the working chamber. In a further advantageous embodiment of the invention, it can be provided that the column The piston ring is equipped with two chamfers, one on each of the two outer circumferential edges of the piston ring. This helps to prevent incorrect installation in series production. In a further advantageous embodiment of the invention, the piston ring can be designed as a closed or slotted piston ring, particularly with variations in the slot/groove geometry. A piston ring without a slot is the preferred variant with regard to sealing performance, since no gas can escape from the compression chamber through the groove/gap. However, the slotted variant is more challenging for mounting the piston ring to the piston, as the ring must be stretched considerably to fit it to the piston.