A differential piston for a symmetrical balanced compressor

Abstract

This utility model discloses a differential piston for a symmetrical balanced compressor, relating to the field of reciprocating compressor technology. It includes a piston rod with a narrow-diameter end and a wide-diameter end. A low-pressure piston is installed at the narrow-diameter end, and a high-pressure piston is installed at the wide-diameter end. A conical limiting block is fixedly installed at the narrow-diameter end, and the low-pressure piston is mounted on the conical limiting block. A locking nut is threaded onto the upper end of the conical limiting block. Several anti-rotation pins are provided between the locking nut and the low-pressure piston. The low-pressure piston is heated in an oven, and then its inner bore mates with the limiting groove. After cooling, an interference fit is achieved. The locking nut is then tightened, and the anti-rotation pins are inserted through, achieving axial limiting of the low-pressure piston and longitudinal locking of the locking nut. This solves the problem in the prior art where the piston rod and low-pressure piston have an interference fit, which relies solely on heating assembly and may loosen due to thermal stress after long-term operation.

Description

Technical Field

[0001] This utility model relates to the field of piston compressor technology, specifically a differential piston for a symmetrical balanced compressor. Background Technology

[0002] The stage piston of the symmetrical balanced compressor is a complex piston that combines a multi-stage piston with a symmetrical balanced body layout, achieving a balance of power, compact structure and high efficiency. Chinese utility model patent application CN207777115U discloses a stepped piston for a symmetrical balanced compressor: it includes a piston rod, which is a stepped rod. A high-pressure piston made of alloy steel is provided on the side of the piston rod with a larger diameter. The piston rod and the high-pressure piston are an integral structure. A low-pressure piston made of cast aluminum is sleeved in the middle of the piston rod. A stepped through hole is provided on the axis of the low-pressure piston. The stepped through hole is sleeved on the piston rod, and the piston rod and the low-pressure piston are interference-fitted. A low-pressure guide ring and four low-pressure piston rings are sleeved on the low-pressure piston. The low-pressure piston is located on the side close to the high-pressure piston.

[0003] However, existing technologies still have shortcomings: The piston rod and the low-pressure piston are interference-fitted. The interference fit relies solely on heating for assembly, which may loosen due to thermal stress after long-term operation. Furthermore, the low-pressure piston is fixed by only a single interference surface, resulting in insufficient radial positioning accuracy. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a differential piston for a symmetrical balanced compressor to solve the problem in the prior art where the piston rod and low-pressure piston are in an interference fit, which relies solely on heating for assembly and may loosen due to thermal stress after long-term operation.

[0005] To achieve the above objectives, this utility model proposes a differential piston for a symmetrical balanced compressor, comprising a piston rod, the piston rod having a narrow diameter end and a wide diameter end; a low-pressure piston is installed at the narrow diameter end, a high-pressure piston is installed at the wide diameter end, a conical limiting block is fixedly provided at the narrow diameter end, the low-pressure piston is disposed on the conical limiting block, a locking nut is threaded on the upper end of the conical limiting block, and a plurality of anti-rotation pins are provided between the locking nut and the low-pressure piston.

[0006] As a further embodiment of this utility model: the conical limiting block is provided with a plurality of limiting grooves, and the low-pressure piston is provided with a piston inner hole.

[0007] As a further embodiment of this utility model: the inner hole of the piston is designed with a stepped taper to match the conical limiting block and the limiting groove.

[0008] As a further embodiment of this utility model: the low-pressure piston is interference-fitted with the conical limiting block through the limiting groove.

[0009] As a further embodiment of this utility model: a threaded rod is fixedly provided on the piston rod, the threaded rod is provided at the end of the narrow diameter end away from the wide diameter end, and a nut is threaded on the threaded rod.

[0010] As a further embodiment of this utility model: a wave spring washer is provided between the nut and the threaded rod.

[0011] As a further embodiment of this invention, a high-pressure piston ring is fitted onto the high-pressure piston.

[0012] As a further embodiment of this invention, a guide ring is provided on the low-pressure piston.

[0013] As a further embodiment of this utility model: a low-pressure piston ring is provided on the low-pressure piston, and the low-pressure piston ring is disposed on both sides of the guide ring.

[0014] As a further embodiment of this invention, the high-pressure piston and the wide-diameter end are an integrated structure.

[0015] Compared with the prior art, the beneficial effects of this utility model are: By setting a conical limiting block on the narrow diameter end of the piston rod, and placing a low-pressure piston on the conical limiting block, a triple positioning and anti-loosening mechanism optimizes the low-pressure piston connection. First, several limiting grooves are opened on the conical limiting block, and an inner hole is opened inside the low-pressure piston. The inner hole of the piston is designed with a stepped taper to match the conical limiting block and the limiting grooves. The low-pressure piston is interference-fitted with the conical limiting block through the limiting grooves. The setting of the limiting grooves and the piston inner hole improves the radial positioning accuracy of the low-pressure piston. Second, a locking nut is threaded on the upper end of the conical limiting block. The locking nut increases the axial preload on the low-pressure piston. Finally, several anti-rotation pins are set between the locking nut and the low-pressure piston. The anti-rotation pins radially limit the locking nut, preventing vibration from causing the locking nut to rotate during operation, thereby optimizing the stability of the low-pressure piston connection. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a schematic diagram of the piston rod of this utility model; Figure 4 This utility model Figure 2 Enlarged view of point A.

[0017] In the diagram: 1. Piston rod; 2. High-pressure piston; 3. Low-pressure piston; 4. Threaded rod; 5. Nut; 6. Locking nut; 7. Anti-rotation pin; 8. Low-pressure piston ring; 9. Guide ring; 10. Narrow diameter end; 11. Wide diameter end; 12. Conical limiting block; 13. Limiting groove; 14. Piston inner hole; 15. High-pressure piston ring. Detailed Implementation

[0018] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0019] like Figure 1-4As shown, a differential piston for a symmetrical balanced compressor includes a piston rod 1, which includes a narrow-diameter end 10 and a wide-diameter end 11. A low-pressure piston 3 is installed at the narrow-diameter end 10, and a guide ring 9 and a low-pressure piston ring 8 are provided on the low-pressure piston 3. The low-pressure piston ring 8 is located on both sides of the guide ring 9. The guide ring 9 prevents the piston or piston rod from directly contacting and rubbing against the cylinder during movement, thus protecting the cylinder and the low-pressure piston 3 or the wide-diameter end 11 from damage. A... High-pressure piston 2, with high-pressure piston ring 15 fitted on it, is an integral structure with the wide-diameter end 11. The high-pressure stage withstands greater gas pressure and inertial force. The integral design eliminates the risk of bolt loosening caused by bolted connections and improves the overall installation efficiency of the device. The low-pressure stage is subjected to less force, and the interference fit provides sufficient constraint. Therefore, the low-pressure piston 3 is not integrally set. This design combines economy and load performance, facilitates hot assembly and disassembly, and makes maintenance and replacement more convenient. A conical limiting block 1 is fixedly installed at the narrow-diameter end 10. 2. The conical limiting block 12 has several limiting grooves 13, and the low-pressure piston 3 has a piston inner hole 14. The piston inner hole 14 is designed with a stepped taper to match the conical limiting block 12 and the limiting grooves 13. The low-pressure piston 3 is interference-fitted with the conical limiting block 12 through the limiting grooves 13. The setting of the limiting grooves 13 and the piston inner hole 14 can improve the radial positioning accuracy of the low-pressure piston 3. A locking nut 6 is threaded on the upper end of the conical limiting block 12, and several anti-rotation pins 7 are set between the locking nut 6 and the low-pressure piston 3. Nut 6 increases the axial preload on the low-pressure piston 3. The anti-rotation pin 7 radially limits the locking nut 6 to prevent it from rotating due to vibration during operation. During installation, the low-pressure piston 3 is heated in an oven. Then, the low-pressure piston 3 is inserted from the narrow diameter end 10 until it is fitted into the conical limiting block 12. The piston inner hole 14 is matched with the limiting groove 13. After cooling, an interference fit is achieved. Then, the locking nut 6 is tightened. Next, the anti-rotation pin 7 is inserted through to achieve axial limiting of the low-pressure piston 3 and longitudinal locking of the locking nut 6. As one embodiment of this invention, a threaded rod 4 is fixedly provided on the piston rod 1. The threaded rod 4 is located at the end of the narrow diameter end 10 away from the wide diameter end 11. A nut 5 is threaded on the threaded rod 4, and a wave spring washer is provided between the nut 5 and the threaded rod 4 to absorb vibration.

[0020] Working principle: The high-pressure piston 2 is a one-piece structure that is directly inserted into the cylinder without any additional operation. The low-pressure piston 3 is heated to 120°C in an oven and kept at that temperature for 2 hours. Then, the low-pressure piston 3 is inserted from the narrow diameter end 10 until it fits into the conical limiting block 12. The piston inner hole 14 is matched with the limiting groove 13. After cooling, an interference fit is achieved. Then, the locking nut 6 is tightened, and then the anti-rotation pin 7 is inserted through to achieve axial limiting of the low-pressure piston 3 and longitudinal locking of the locking nut 6.

[0021] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0022] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A differential piston for a symmetrical balanced compressor, comprising a piston rod (1), the piston rod (1) comprising a narrow-diameter end (10) and a wide-diameter end (11); a low-pressure piston (3) is mounted at the narrow-diameter end (10), and a high-pressure piston (2) is mounted at the wide-diameter end (11), characterized in that, A conical limiting block (12) is fixedly provided at the narrow diameter end (10), and the low-pressure piston (3) is provided on the conical limiting block (12). A locking nut (6) is threaded on the upper end of the conical limiting block (12), and a number of anti-rotation pins (7) are provided between the locking nut (6) and the low-pressure piston (3).

2. A differential piston for a symmetrical balanced compressor according to claim 1, characterized in that The conical limiting block (12) has several limiting grooves (13), and the low-pressure piston (3) has a piston inner hole (14).

3. A differential piston for a symmetrical balanced compressor according to claim 2, characterized in that The piston inner bore (14) is designed with a stepped taper to match the conical limiting block (12) and the limiting groove (13).

4. A differential piston for a symmetrical balanced compressor according to claim 3, wherein The low-pressure piston (3) is interference-fitted with the conical limiting block (12) through the limiting groove (13).

5. A differential piston for a symmetrical balanced compressor according to claim 1, characterized in that, A threaded rod (4) is fixedly provided on the piston rod (1). The threaded rod (4) is located at the end of the narrow diameter end (10) away from the wide diameter end (11). A nut (5) is threaded on the threaded rod (4).

6. A differential piston for a symmetrical balanced compressor according to claim 5, characterized in that A wave spring washer is provided between the nut (5) and the threaded rod (4).

7. A differential piston for a symmetrical balanced compressor according to claim 1, wherein A high-pressure piston ring (15) is fitted onto the high-pressure piston (2).

8. A differential piston for a symmetrical balanced compressor according to claim 1, wherein The low-pressure piston (3) is provided with a guide ring (9).

9. A differential piston for a symmetrical balanced compressor according to claim 8, characterized in that The low-pressure piston (3) is provided with a low-pressure piston ring (8), which is located on both sides of the guide ring (9).

10. A differential piston for a symmetrical balanced compressor according to claim 1, characterized in that, The high-pressure piston (2) and the wide-diameter end (11) are an integrated structure.

Images