Oil pumping structure of reciprocating compressor

Abstract

The utility model discloses a pump oil structure of reciprocating compressor relates to the lubrication field of pump, this pump oil structure, including crankcase and crankshaft and piston, the crankshaft includes long axle and short axle and balance arm, long axle and short axle are connected through balance arm, long axle and short axle oil circuit connection, the outside of long axle is equipped with oil circuit helical groove, be equipped with main oil circuit in long axle, the lower oil hole of main oil circuit end and oil circuit helical groove most lower end intercommunication. Through the inside setting oil hole of long axle and piston cavity intercommunication, make long axle wall on oil circuit helical groove can pump to the position department of short axle oil circuit with lubricating oil. Through short axle oil hole, lubricating oil is pumped into piston cavity from long axle, and utilize the rotation of short axle, and lubricating oil is from short axle oil hole, and more evenly is thrown to the inside of piston cavity. And can realize the circulation lubricating oil of exhaust simultaneously through two air hole sections.

Description

Technical Field

[0001] This utility model relates to the field of refrigeration compressors, specifically to a pump oil structure for a reciprocating compressor for pump lubrication. Background Technology

[0002] Refrigeration compressors are widely used in daily life and production. Because the piston of a refrigeration compressor needs to reciprocate at a high frequency, the long shaft that drives the piston needs to rotate rapidly. In order to avoid excessive friction between the long shaft and the crankshaft bore, which would cause serious heat generation, an oil passage spiral groove needs to be opened on the long shaft to extract the lubricating oil from the oil sump, so that the lubricating oil is evenly distributed between the long shaft and the crankshaft bore, thereby improving heat dissipation and reducing friction.

[0003] In the prior art, the piston chamber and the long shaft are isolated. Therefore, the lubrication of the components in the piston chamber and the long shaft need to be carried out separately, which is not conducive to the circulation of lubricating oil inside the compressor. For example, in the "Oil Circuit Control System for Reciprocating Piston Compressor" disclosed in CN116557263A, oil grooves are provided at both ends of the crank to meet the lubrication needs of the upper and lower ends respectively. However, the upper and lower ends are not connected to each other, which is not conducive to the circulation of lubricating oil. Utility Model Content

[0004] The purpose of this invention is to provide an oil pumping structure for a reciprocating compressor, which can draw lubricating oil from the oil sump at the lower end of the long shaft to the piston chamber, thereby fully lubricating the piston and piston bore, as well as the long shaft and crankshaft bore, and reducing friction. Another purpose of this invention is to provide a second vent section between the balance arm and the long shaft, which can discharge gas in the lubricating oil into the piston chamber when pumping begins, and allow the lubricating oil in the piston chamber to flow back to the oil sump and be drawn back to the outer wall of the long shaft or the piston chamber, completing the oil circulation.

[0005] This utility model achieves the above-mentioned technical objectives through the following technical means:

[0006] An oil pumping structure for a reciprocating compressor includes a crankcase, a crankshaft, and a piston. The crankshaft includes a long shaft, a short shaft, and a balance arm. The long shaft and the short shaft are connected by the balance arm. The long shaft and the short shaft are connected by an oil passage. An oil passage spiral groove is provided on the outer side of the long shaft. A main oil passage is provided inside the long shaft. The end of the main oil passage is connected to the lower oil hole at the bottom of the oil passage spiral groove.

[0007] Furthermore, an oil inlet hole is provided at the upper end of the oil circuit spiral groove, the oil inlet hole is connected to the variable oil circuit in the long shaft, and the variable oil circuit is connected to the short shaft oil circuit in the long shaft.

[0008] Furthermore, the oil inlet of the long shaft and the oil outlet of the short shaft are connected through the variable oil passage and the short shaft oil passage.

[0009] Furthermore, the short shaft is connected to the piston via a connecting rod, and an oil outlet hole is provided on the outer side of the short shaft, located near the oil outlet of the short shaft. An oil slinger groove is also provided on the outer side of the short shaft.

[0010] Preferably, the upper section of the main oil passage is connected to the first vent section, and the upper end of the first vent section is connected to the second vent section.

[0011] Furthermore, the first vent section and the second vent section are not connected to the oil passage spiral groove.

[0012] Preferably, the second vent section is connected to the balance arm.

[0013] Furthermore, the inner diameter of the main oil passage is larger than the inner diameter of the first vent section, and the inner diameter of the first vent section is larger than the inner diameter of the second vent section.

[0014] Furthermore, the long shaft is sleeved in the crankshaft hole of the crankcase and mates with the crankshaft hole, and the oil passage spiral groove completely covers the inner wall of the crankshaft hole.

[0015] Preferably, the piston reciprocates within the piston bore of the crankcase.

[0016] This utility model has the following beneficial effects:

[0017] Compared to the comparative technology that sets oil grooves at both the long and short shafts to meet the lubrication needs of the piston chamber and crankshaft bore respectively, this invention sets an oil hole inside the long shaft that communicates with the piston chamber, allowing the spiral grooves on the long shaft wall to pump lubricating oil to the short shaft oil passage. Lubricating oil is pumped from the long shaft into the piston chamber through the short shaft oil outlet, and the rotation of the short shaft further evenly distributes the lubricating oil into the piston chamber. Furthermore, lubricating oil can be circulated while exhausting gas through two gas port sections. Additionally, depending on the compressor's operating conditions, the crankshaft with adjustable oil passages can be selected at different angles during the initial operation, thereby changing the pressure loss and flow resistance of the lubricating oil in that path, ensuring a reasonable flow rate to each lubrication point under corresponding operating conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the crankcase assembly structure of this utility model.

[0019] Figure 2 This is a schematic diagram of the crankshaft structure of this utility model.

[0020] In the diagram, 1-long shaft, 2-short shaft, 3-balance arm, 4-main oil passage, 5-upper oil hole, 6-lower oil hole, 7-short shaft oil outlet, 8-oil slinger groove, 9-first air hole section, 10-crankcase, 11-crankshaft bore, 12-connecting rod, 13-piston, 14-piston bore, 15-oil passage spiral groove, 16-changeable oil passage, 17-short shaft oil passage, 18-second air hole section. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0022] Example 1:

[0023] like Figure 1 and Figure 2 As shown, an oil pumping structure for a reciprocating compressor includes a crankcase 10, a crankshaft, and a piston 13. The crankshaft includes a long shaft 1, a short shaft 2, and a balance arm 3. The long shaft 1 and the short shaft 2 are connected by the balance arm 3. The long shaft 1 and the short shaft 2 are connected by an oil passage. An oil passage spiral groove 15 is provided on the outer side of the long shaft 1. A main oil passage 4 is provided inside the long shaft 1. The end of the main oil passage 4 is connected to the lower oil hole 6 at the lowest end of the oil passage spiral groove 15.

[0024] In this embodiment, the reciprocating compressor's oil pump structure has the crankshaft and piston components housed inside the crankcase 10. The crankcase 10 serves as the basic support structure for the entire compressor's moving components. Inside the crankcase 10 are crankshaft bores 11 that accommodate and support the crankshaft's rotation, and piston bores 14 that guide the piston 13 in its reciprocating linear motion. An oil sump is located below the long shaft 1 to store lubricating oil, serving as the oil source for the entire lubrication system.

[0025] Figure 2 This is a schematic diagram of the crankshaft structure of this utility model. The short shaft 2 is hinged to the piston 13 via connecting rod 12, thereby driving the piston 13 to reciprocate. The crankshaft as a whole consists of a long shaft 1, a short shaft 2, and a balance arm 3 for connecting the two. The long shaft 1, as the main shaft, is used to connect to an external power source to drive the rotation of the entire crankshaft. The long shaft 1 is located in the crankshaft hole 11 of the crankcase 10, forming a fit with the inner wall of the crankshaft hole 11. The balance arm 3 is a counterweight used to balance the inertial force generated during the reciprocating motion of the piston assembly, thereby reducing the vibration of the entire machine, and simultaneously fixing the long shaft 1 and the short shaft 2 together. The short shaft 2 is hinged to the piston 13 via connecting rod 12. When the long shaft 1 rotates at high speed, the balance arm 3 drives the short shaft 2 to perform eccentric circular motion, which in turn drives the connecting rod 12 and the piston 13 to perform high-frequency reciprocating linear motion within the piston hole 14, thereby achieving gas compression.

[0026] This invention, through the design of an integrated, circulating oil pump lubrication structure, achieves unified oil supply from a single oil sump to the long shaft lubrication interface and piston cavity lubrication area via an oil circuit structure set on and inside the crankshaft.

[0027] An oil passage spiral groove 15 is machined on the outer cylindrical surface of the long shaft 1. The oil passage spiral groove 15 starts from the lower end of the long shaft 1, i.e. the top of the main oil passage 4, and extends axially upward along the outer wall of the long shaft 1 to the upper part of the long shaft 1, i.e. above the first air hole section 9 and below the balance arm 3.

[0028] When the long shaft 1 rotates within the crankshaft bore 11, the lubricating oil in the main oil passage 4 is lifted to the position of the lower oil hole 6 under the combined drive of the oil surface pressure difference generated by the rotation and centrifugal force. The lubricating oil flowing out from the lower oil hole 6 enters the oil passage spiral groove 15. A portion of the lubricating oil leaks from the oil passage spiral groove 15 into the gap between the long shaft 1 and the crankshaft bore 11, and as the long shaft 1 rotates, it is evenly coated on the outer wall of the long shaft 1 and the inner wall of the crankshaft bore 11, thereby lubricating the long shaft 1 and the crankshaft bore 11, reducing friction and enhancing heat dissipation. The other portion of the lubricating oil is continuously lifted along the oil passage spiral groove 15, eventually reaching the position of the upper oil hole 5.

[0029] In the upper region of the pumping path of the oil passage spiral groove 15, an oil inlet 5 is provided on the shaft wall of the long shaft 1. A variable oil passage 16 is provided inside the long shaft 1 and connected to the oil inlet 5. The oil inlet 5 is the oil passage inlet for lubricating oil to the short shaft 2, and can effectively obtain the lubricating oil pumped up by the oil passage spiral groove 15.

[0030] After entering through the upper oil hole 5, the lubricating oil first flows through the adjustable oil passage 16 inside the long shaft 1. The adjustable oil passage 16 connects to the short shaft oil passage 17 and finally connects to the short shaft oil outlet 7 of the short shaft 2. The adjustable characteristic of the adjustable oil passage 16 is reflected in the fact that during the crankshaft design process, the machining structure of the adjustable oil passage 16 can be adjusted according to the compressor's operating state at the time of design simply by changing the tilt angle and extension length of the adjustable oil passage 16 and making corresponding adjustments to the structure of the short shaft oil passage 17. This improves the efficiency of the compressor under the corresponding operating conditions, without the need to redesign the external structure of the crankshaft, including the oil passage spiral groove 15, as is required for traditional crankshafts, thus improving efficiency and reducing costs.

[0031] By changing the tilt angle and extension length of the adjustable oil passage 16, the oil resistance of the lubricating oil can be altered, thus achieving a balance between lubrication effect and oil injection control. The end of the adjustable oil passage 16 seamlessly connects to the short shaft oil passage 17. The short shaft oil passage 17 is an internal oil passage for the long shaft 1, the short shaft 2, and the balance arm 3. The short shaft oil passage 17 starts inside the long shaft 1, passes through the balance arm 3, and finally extends to the short shaft 2, communicating with the short shaft oil outlet 7 located in the side wall opening of the short shaft 2. The short shaft oil passage forms a completely closed lubricating oil passage from the long shaft 1 to the short shaft 2.

[0032] This pumps the lubricating oil in the main oil passage 4 into the piston chamber, thereby lubricating the piston chamber. Simultaneously, to ensure smooth pumping of the lubricating oil to the short shaft oil outlet 7, the diameter of the short shaft oil passage 17 is relatively small. Although the short shaft oil passage 17 extends all the way to the top of the short shaft 2, the lubricating oil is more easily ejected from the short shaft oil outlet 7 located in the middle of the short shaft oil passage 17, rather than from the top of the short shaft oil passage 17.

[0033] The endpoint of the short shaft oil passage 17 is the short shaft oil outlet 7, which is formed on the outer cylindrical surface of the short shaft 2. Lubricating oil is delivered here via the variable oil passage 16 and the short shaft oil passage 17, and is sprayed out from the short shaft oil outlet 7. To ensure that the sprayed liquid lubricating oil can be evenly splashed and covered to the entire inner wall of the piston chamber, an oil-throwing groove 8 is also machined on the outer surface of the short shaft 2 around the periphery of the short shaft oil outlet 7. The oil-throwing groove 8 connects the short shaft oil outlet 7 and the upper end of the short shaft 2. When the short shaft 2 rotates at high speed, most of the lubricating oil thrown out from the oil outlet 7 can be effectively atomized under the action of centrifugal force and thrown out along the structure of the oil-throwing groove 8, thereby achieving splash lubrication of the piston moving components.

[0034] To improve the stability of the lubrication system and achieve overall recycling of the lubricating oil, rather than recycling the lubricating oil in the long shaft 1 and the crankshaft bore 11, this utility model also designs an oil return channel.

[0035] The return oil channel is composed of the main oil passage 4, the first vent section 9, and the second vent section 18 connected in series. This channel system is structurally and functionally independent of the aforementioned oil passage spiral groove 15, and no direct fluid exchange occurs between them.

[0036] At the axial center of the long shaft 1, there is a main axial channel, namely the main oil passage 4. The main oil passage 4 is the starting point for the lifting of the lubricating oil and the ending point for the return flow of the lubricating oil circulation. The main oil passage 4 is immersed in the oil sump and forms an oil seal surface. The inner wall at the upper end of the main oil passage 4 is connected to the lowermost region of the oil passage spiral groove 15 through the lower oil hole 6.

[0037] The upper end of the main oil passage 4 is connected to the first vent section 9 inside the long shaft 1. The first vent section 9 continues to extend upward and connects to the second vent section 18. The inner diameter of the main oil passage 4 is the largest, the inner diameter of the first vent section 9 is the second largest, and the inner diameter of the second vent section 18 is the smallest.

[0038] The outlet of the second vent section 18 is located at the upper end face of the balance arm 3. Due to the sealed state of the main oil passage 4, the pressure inside the long shaft 1 is equal to the pressure inside the piston chamber.

[0039] Because the air density mixed in the lubricating oil is much lower than that of the oil, under the action of centrifugal force and pressure, the air bubbles tend to aggregate and escape along the path of least resistance. Therefore, the first air vent section 9 and the second air vent section 18, which connect upwards, constitute a path that is more favorable for gas flow. Thus, the gas in the lubricating oil mixed into the oil sump during the initial pumping process or during operation will be preferentially discharged and enter the piston chamber through this channel, avoiding air resistance in the main oil circuit.

[0040] After splash lubrication in the piston chamber, excess lubricating oil accumulates at the bottom of the balance arm 3. Since the outlet of the second vent section 18 is connected to the piston chamber, this excess lubricating oil can flow into the second vent section 18 through this outlet under the action of gravity and the pressure gradient in the chamber, and fall directly into the oil sump in the main oil passage 4 under the action of gravity, thus constructing a complete, self-regulating lubricating oil circulation system.

[0041] Example 2:

[0042] This embodiment has the same structure as Embodiment 1, and further describes the complete process of oil pumping, venting, and oil circulation of this utility model.

[0043] like Figure 1 and Figure 2 As shown, an oil pumping structure for a reciprocating compressor includes a crankcase 10, a crankshaft, and a piston 13. The crankshaft includes a long shaft 1, a short shaft 2, and a balance arm 3. The long shaft 1 and the short shaft 2 are connected by the balance arm 3. The long shaft 1 and the short shaft 2 are connected by an oil passage. An oil passage spiral groove 15 is provided on the outer side of the long shaft 1. A main oil passage 4 is provided inside the long shaft 1. The end of the main oil passage 4 is connected to the lower oil hole 6 at the lowest end of the oil passage spiral groove 15.

[0044] In this embodiment, the reciprocating compressor's oil pump structure has the crankshaft and piston components housed inside the crankcase 10. The crankcase 10 serves as the basic support structure for the entire compressor's moving components. Inside the crankcase 10 are crankshaft bores 11 that accommodate and support the crankshaft's rotation, and piston bores 14 that guide the piston 13 in its reciprocating linear motion. An oil sump is located below the long shaft 1 to store lubricating oil, serving as the oil source for the entire lubrication system.

[0045] Figure 2 This is a schematic diagram of the crankshaft structure of this utility model. The short shaft 2 is hinged to the piston 13 via connecting rod 12, thereby driving the piston 13 to reciprocate. The crankshaft as a whole consists of a long shaft 1, a short shaft 2, and a balance arm 3 for connecting the two. The long shaft 1, as the main shaft, is used to connect to an external power source to drive the rotation of the entire crankshaft. The long shaft 1 is located in the crankshaft hole 11 of the crankcase 10, forming a fit with the inner wall of the crankshaft hole 11. The balance arm 3 is a counterweight used to balance the inertial force generated during the reciprocating motion of the piston assembly, thereby reducing the vibration of the entire machine, and simultaneously fixing the long shaft 1 and the short shaft 2 together. The short shaft 2 is hinged to the piston 13 via connecting rod 12. When the long shaft 1 rotates at high speed, the balance arm 3 drives the short shaft 2 to perform eccentric circular motion, which in turn drives the connecting rod 12 and the piston 13 to perform high-frequency reciprocating linear motion within the piston hole 14, thereby achieving gas compression.

[0046] This invention, through the design of an integrated, circulating oil pump lubrication structure, achieves unified oil supply from a single oil sump to the long shaft lubrication interface and piston cavity lubrication area via an oil circuit structure set on and inside the crankshaft.

[0047] An oil passage spiral groove 15 is machined on the outer cylindrical surface of the long shaft 1. The oil passage spiral groove 15 starts from the lower end of the long shaft 1, i.e. the top of the main oil passage 4, and extends axially upward along the outer wall of the long shaft 1 to the upper part of the long shaft 1, i.e. above the first air hole section 9 and below the balance arm 3.

[0048] When the long shaft 1 rotates within the crankshaft bore 11, the lubricating oil in the main oil passage 4 is lifted to the position of the lower oil hole 6 under the combined drive of the oil surface pressure difference generated by the rotation and centrifugal force. The lubricating oil flowing out from the lower oil hole 6 enters the oil passage spiral groove 15. A portion of the lubricating oil leaks from the oil passage spiral groove 15 into the gap between the long shaft 1 and the crankshaft bore 11, and as the long shaft 1 rotates, it is evenly coated on the outer wall of the long shaft 1 and the inner wall of the crankshaft bore 11, thereby lubricating the long shaft 1 and the crankshaft bore 11, reducing friction and enhancing heat dissipation. The other portion of the lubricating oil is continuously lifted along the oil passage spiral groove 15, eventually reaching the position of the upper oil hole 5.

[0049] In the upper region of the pumping path of the oil passage spiral groove 15, an oil inlet 5 is provided on the shaft wall of the long shaft 1. A variable oil passage 16 is provided inside the long shaft 1 and connected to the oil inlet 5. The oil inlet 5 is the oil passage inlet for lubricating oil to the short shaft 2, and can effectively obtain the lubricating oil pumped up by the oil passage spiral groove 15.

[0050] After entering through the upper oil hole 5, the lubricating oil first flows through the adjustable oil passage 16 inside the long shaft 1. The adjustable oil passage 16 connects to the short shaft oil passage 17 and finally connects to the short shaft oil outlet 7 of the short shaft 2. The adjustable characteristic of the adjustable oil passage 16 is reflected in the fact that during the crankshaft design process, the machining structure of the adjustable oil passage 16 can be adjusted according to the compressor's operating state at the time of design simply by changing the tilt angle and extension length of the adjustable oil passage 16 and making corresponding adjustments to the structure of the short shaft oil passage 17. This improves the efficiency of the compressor under the corresponding operating conditions, without the need to redesign the external structure of the crankshaft, including the oil passage spiral groove 15, as is required for traditional crankshafts, thus improving efficiency and reducing costs.

[0051] By changing the tilt angle and extension length of the adjustable oil passage 16, the oil resistance of the lubricating oil can be altered, thus achieving a balance between lubrication effect and oil injection control. The end of the adjustable oil passage 16 seamlessly connects to the short shaft oil passage 17. The short shaft oil passage 17 is an internal oil passage for the long shaft 1, the short shaft 2, and the balance arm 3. The short shaft oil passage 17 starts inside the long shaft 1, passes through the balance arm 3, and finally extends to the short shaft 2, communicating with the short shaft oil outlet 7 located in the side wall opening of the short shaft 2. The short shaft oil passage forms a completely closed lubricating oil passage from the long shaft 1 to the short shaft 2.

[0052] This pumps the lubricating oil in the main oil passage 4 into the piston chamber, thereby lubricating the piston chamber. Simultaneously, to ensure smooth pumping of the lubricating oil to the short shaft oil outlet 7, the diameter of the short shaft oil passage 17 is relatively small. Although the short shaft oil passage 17 extends all the way to the top of the short shaft 2, the lubricating oil is more easily ejected from the short shaft oil outlet 7 located in the middle of the short shaft oil passage 17, rather than from the top of the short shaft oil passage 17.

[0053] The endpoint of the short shaft oil passage 17 is the short shaft oil outlet 7, which is formed on the outer cylindrical surface of the short shaft 2. Lubricating oil is delivered here via the variable oil passage 16 and the short shaft oil passage 17, and is sprayed out from the short shaft oil outlet 7. To ensure that the sprayed liquid lubricating oil can be evenly splashed and covered to the entire inner wall of the piston chamber, an oil-throwing groove 8 is also machined on the outer surface of the short shaft 2 around the periphery of the short shaft oil outlet 7. The oil-throwing groove 8 connects the short shaft oil outlet 7 and the upper end of the short shaft 2. When the short shaft 2 rotates at high speed, most of the lubricating oil thrown out from the oil outlet 7 can be effectively atomized under the action of centrifugal force and thrown out along the structure of the oil-throwing groove 8, thereby achieving splash lubrication of the piston moving components.

[0054] To improve the stability of the lubrication system and achieve overall recycling of the lubricating oil, rather than recycling the lubricating oil in the long shaft 1 and the crankshaft bore 11, this utility model also designs an oil return channel.

[0055] The return oil channel is composed of the main oil passage 4, the first vent section 9, and the second vent section 18 connected in series. This channel system is structurally and functionally independent of the aforementioned oil passage spiral groove 15, and no direct fluid exchange occurs between them.

[0056] At the axial center of the long shaft 1, there is a main axial channel, namely the main oil passage 4. The main oil passage 4 is the starting point for the lifting of the lubricating oil and the ending point for the return flow of the lubricating oil circulation. The main oil passage 4 is immersed in the oil sump and forms an oil seal surface. The inner wall at the upper end of the main oil passage 4 is connected to the lowermost region of the oil passage spiral groove 15 through the lower oil hole 6.

[0057] The upper end of the main oil passage 4 is connected to the first vent section 9 inside the long shaft 1. The first vent section 9 continues to extend upward and connects to the second vent section 18. The inner diameter of the main oil passage 4 is the largest, the inner diameter of the first vent section 9 is the second largest, and the inner diameter of the second vent section 18 is the smallest.

[0058] The outlet of the second vent section 18 is located at the upper end face of the balance arm 3. Due to the sealed state of the main oil passage 4, the pressure inside the long shaft 1 is equal to the pressure inside the piston chamber.

[0059] Because the air density mixed in the lubricating oil is much lower than that of the oil, under the action of centrifugal force and pressure, the air bubbles tend to aggregate and escape along the path of least resistance. Therefore, the first air vent section 9 and the second air vent section 18, which connect upwards, constitute a path that is more favorable for gas flow. Thus, the gas in the lubricating oil mixed into the oil sump during the initial pumping process or during operation will be preferentially discharged and enter the piston chamber through this channel, avoiding air resistance in the main oil circuit.

[0060] After splash lubrication in the piston chamber, excess lubricating oil accumulates at the bottom of the balance arm 3. Since the outlet of the second vent section 18 is connected to the piston chamber, this excess lubricating oil can flow into the second vent section 18 through this outlet under the action of gravity and the pressure gradient in the chamber, and fall directly into the oil sump in the main oil passage 4 under the action of gravity, thus constructing a complete, self-regulating lubricating oil circulation system.

[0061] When the compressor starts and the external power source drives the long shaft 1 to rotate at high speed within the crankshaft bore 11, the lubricating oil in the main oil passage 4, immersed in the oil sump, is lifted to the lower oil hole 6 at the upper end of the main oil passage 4 under the combined drive of the oil surface pressure difference generated by the rotation and centrifugal force. The lubricating oil flows out from the lower oil hole 6 and enters the lower end of the oil passage spiral groove 15 on the outer wall of the long shaft 1. As the long shaft 1 continues to rotate, the oil passage spiral groove 15 acts like a spiral pump, pumping the lubricating oil upward axially. During this pumping process, a portion of the lubricating oil leaks from the gap between the oil passage spiral groove 15 and the crankshaft bore 11, and is evenly coated between the outer wall of the long shaft 1 and the inner wall of the crankshaft bore 11, achieving continuous lubrication and heat dissipation of this lubrication interface; another portion of the lubricating oil is continuously lifted to the upper region of the oil passage spiral groove 15 and enters the interior of the crankshaft through the upper oil hole 5.

[0062] The lubricating oil entering the crankshaft first flows through the variable oil passage 16, and then seamlessly enters the short shaft oil passage 17. Within the short shaft oil passage 17, the lubricating oil is transported, passes through the balance arm 3, and finally reaches the short shaft oil outlet 7 located on the side wall of the short shaft 2. Due to centrifugal force, the lubricating oil is ejected at high speed from the short shaft oil outlet 7, and under the guidance of the oil slinger 8, it is evenly splashed and covers the entire inner wall of the piston chamber, thereby achieving effective splash lubrication of the moving components such as the piston 13, connecting rod 12, and short shaft 2.

[0063] Meanwhile, air that may be mixed into the lubricating oil, due to its much lower density than oil, tends to converge towards the center of rotation, i.e., the axis of the long shaft 1, in the centrifugal force field generated by the crankshaft rotation. An independent channel located at the axis, consisting of the main oil passage 4, the first air port section 9, and the second air port section 18 connected in series, constitutes a preferential exhaust path due to its minimal resistance to gas flow. Therefore, gas mixed into the lubricating oil is preferentially discharged through this channel, passing sequentially through the first air port section 9 and the second air port section 18, and finally entering the piston chamber through the outlet located on the upper end face of the balance arm 3. This process effectively avoids air resistance in the main oil passage 4 or the oil passage spiral groove 15, ensuring the stability and continuity of the pumped oil.

[0064] After splash lubrication is completed in the piston chamber, excess lubricating oil falls and accumulates at the bottom and upper surface of the balance arm 3 under the influence of gravity. This accumulated lubricating oil flows into the return oil channel through the outlet of the second vent section 18, which is shared with the exhaust channel and located at the upper end of the balance arm 3, under the combined action of gravity and the pressure gradient within the chamber. The lubricating oil then flows sequentially through the second vent section 18 and the first vent section 9, finally falling directly back to the lower part of the main oil passage 4 and flowing into the oil sump. Thus, the structure completes a full closed-loop cycle from oil sump pumping, dual-path lubrication, gas separation and discharge to lubricating oil recovery, achieving continuous and stable lubrication of the entire compressor's moving components and the recycling of lubricating oil.

Claims

1. An oil pump structure for a reciprocating compressor, characterized in that, The crankcase (10) includes a crankshaft and a piston (13). The crankshaft includes a long shaft (1), a short shaft (2), and a balance arm (3). The long shaft (1) and the short shaft (2) are connected by the balance arm (3). The long shaft (1) and the short shaft (2) are connected by an oil passage. The outer side of the long shaft (1) is provided with an oil passage spiral groove (15). The long shaft (1) is provided with a main oil passage (4). The end of the main oil passage (4) is connected to the lower oil hole (6) at the bottom of the oil passage spiral groove (15).

2. The oil pump structure of a reciprocating compressor according to claim 1, characterized in that, An oil inlet hole (5) is provided at the upper end of the spiral groove (15) of the oil passage. The oil inlet hole (5) is connected to the variable oil passage (16) in the long shaft (1). The variable oil passage (16) is connected to the short shaft oil passage (17) in the long shaft (1).

3. The oil pump structure of a reciprocating compressor according to claim 2, characterized in that, The oil hole (5) of the long shaft (1) and the oil outlet hole (7) of the short shaft (2) are connected by the variable oil passage (16) and the oil passage (17) of the short shaft.

4. The oil pump structure of a reciprocating compressor according to claim 1, 2, or 3, characterized in that, The short shaft (2) is connected to the piston (13) via a connecting rod (12). The short shaft (2) has an oil outlet hole (7) on its outer side, located near the oil outlet (7) of the short shaft. An oil slinger groove (8) is provided on the outer side of the short shaft (2).

5. The oil pump structure of a reciprocating compressor according to claim 1, 2, or 3, characterized in that, The upper section of the main oil passage (4) is connected to the first vent section (9), and the upper end of the first vent section (9) is connected to the second vent section (18).

6. The oil pump structure of a reciprocating compressor according to claim 5, characterized in that, The first vent section (9) and the second vent section (18) are not connected to the oil passage spiral groove (15).

7. The oil pump structure of a reciprocating compressor according to claim 5, characterized in that, The second vent section (18) is connected to the balance arm (3).

8. The oil pump structure of a reciprocating compressor according to claim 5, characterized in that, The inner diameter of the main oil passage (4) is greater than the inner diameter of the first vent section (9), and the inner diameter of the first vent section (9) is greater than the inner diameter of the second vent section (18).

9. The oil pump structure of a reciprocating compressor according to claim 1, 2, 3, 6, 7, or 8, characterized in that, The long shaft (1) is fitted into the crankshaft hole (11) of the crankcase (10) and cooperates with the crankshaft hole (11). The oil passage spiral groove (15) completely covers the inner wall of the crankshaft hole (11).

10. The oil pump structure of a reciprocating compressor according to claim 1, 2, 3, 6, 7, or 8, characterized in that, The piston (13) reciprocates in the piston bore (14) of the crankcase (10).

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