Crankshaft assembly, pump body assembly and rotary compressor

Abstract

The application provides a crankshaft assembly, a pump body assembly and a rotary compressor. The crankshaft assembly comprises a crankshaft and a bearing, the crankshaft is arranged in the bearing; a sealing element is arranged between the crankshaft and the bearing and is located at the end position of the bearing supporting section along the axial direction of the crankshaft. The application arranges the sealing element at the axial end between the crankshaft and the bearing, avoids the direct contact between the crankshaft and the bearing, greatly reduces the leakage of lubricating oil at the axial end, improves the oil film bearing pressure of the end region, makes the whole supporting section have good lubricating effect, reduces the friction power consumption and wear, and makes the compressor run more smoothly and reduce the noise caused by friction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of rotary compressors, and particularly relates to a crankshaft assembly, a pump body assembly and a rotary compressor. BACKGROUND

[0002] A refrigeration compressor is used in a refrigeration system such as an air conditioner, a heat pump and a refrigeration and freezing system, and the reliability and noise level of the compressor are key factors affecting the service life and comfort of the refrigeration product. A conventional rotary compressor pump body structure is mainly composed of a crankshaft, a cylinder, a piston, a vane, a bearing and the like, as shown in FIG. 1. A circular annular piston sleeve is arranged on the crankshaft and rotates eccentrically with the crankshaft. The outer wall of the piston and the inner wall of the cylinder form a crescent-shaped working chamber. The vane in the cylinder sliding groove abuts against the outer wall of the piston, and the crescent-shaped working chamber is divided into a suction chamber and a compression chamber. The volume of the suction chamber and the compression chamber changes periodically with the rotation of the crankshaft, so as to realize the working processes of suction, compression and exhaust. The circular annular outer surface of the piston is subjected to the pressure difference between the suction chamber and the compression chamber, and is also subjected to the centrifugal force of the piston, the crankshaft and the balance block, so that the crankshaft is bent and deformed. Figure 1

[0003] Since the gap between the compressor bearing and the crankshaft is small, generally less than 30 microns, under high speed or heavy load working conditions, the end region of the bearing inner wall along the axial direction of the crankshaft is prone to metal contact with the crankshaft due to the bending deformation of the crankshaft, thereby causing problems such as increased friction power consumption, aggravated wear and tear and deteriorated noise.

[0004] Research has found that within the support range of the sliding bearing, the oil film pressure P in the bearing gap presents a trend of gradually decreasing from both sides to the middle along the axial direction, and the relative pressure of the oil film at the end of the bearing is 0 (the relative pressure refers to the difference between the oil film pressure and the ambient pressure at the end of the bearing), as shown in FIG. 2. Due to the influence of the leakage at the end of the bearing, the closer to the end of the bearing, the lower the oil film pressure, and the lower the support force on the crankshaft, which is not conducive to alleviating the metal contact force between the crankshaft and the bearing. This is also an important reason why the wear area of the crankshaft and the bearing is close to the end of the bearing. Figure 2 SUMMARY

[0005] Therefore, the application provides a crankshaft assembly, a pump body assembly and a rotary compressor, which can solve the problem that the bending deformation of the crankshaft is prone to metal contact with the crankshaft, thereby causing problems such as increased friction power consumption, aggravated wear and tear and deteriorated noise.

[0006] In order to solve the above problems, the application provides a crankshaft assembly, comprising:

[0007] a crankshaft and a bearing, the crankshaft being arranged in the bearing;

[0008] ​​A sealing member is arranged between the crankshaft and the bearing and located at an end position of a supporting section of the bearing supporting the crankshaft along the axial direction of the crankshaft.

[0009] Optionally, the sealing member is provided with at least two sealing members respectively located at two end positions of the supporting section along the axial direction of the crankshaft.

[0010] Optionally, a groove is provided on the crankshaft and / or the bearing, and a portion of the sealing member is fitted in the groove.

[0011] Optionally, the crankshaft assembly further comprises an elastic member arranged in the groove and in contact with the sealing member, and the elastic member applies elastic force to the sealing member so that the sealing member sealingly abuts against the outer circumferential surface of the crankshaft or the inner circumferential surface of the bearing.

[0012] Optionally, the sealing member is in interference fit with the outer circumferential surface of the crankshaft or the inner circumferential surface of the bearing.

[0013] Optionally, the sealing member is made of polytetrafluoroethylene mixed with wear-resistant material, and the mass content of the wear-resistant material is 1-20%.

[0014] Optionally, the wear-resistant material comprises at least one of copper powder, molybdenum disulfide, carbon fiber and graphite.

[0015] Optionally, the crankshaft is subjected to nitriding treatment at least in the region in contact with the sealing member.

[0016] Optionally, along the axial direction of the crankshaft, the width of the groove is Bc, and the width of the sealing member is Bf, and 0 < Bc-Bf < 0.15 mm is satisfied.

[0017] Optionally, a groove is provided on the side surface of the sealing member abutting against the crankshaft or the bearing.

[0018] According to another aspect of the present application, a pump body assembly is provided, comprising the crankshaft assembly as described above.

[0019] According to still another aspect of the present application, a rotary compressor is provided, comprising the crankshaft assembly as described above or the pump body assembly as described above.

[0020] The crankshaft assembly provided by the present application comprises: a crankshaft and a bearing, the crankshaft being arranged in the bearing; and a sealing member arranged between the crankshaft and the bearing and located at an end position of a supporting section of the bearing supporting the crankshaft along the axial direction of the crankshaft.

[0021] The application sets a sealing piece between the crankshaft and the bearing at the axial end, avoids the direct contact between the crankshaft and the bearing, greatly reduces the leakage of lubricating oil at the axial end, improves the oil film bearing pressure of the end region, makes the whole supporting area have good lubricating effect, reduces the friction power consumption and wear, and makes the compressor run more smoothly, reduces the noise caused by friction. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Fig. 1 is a schematic diagram of the internal structure of a traditional rotary compressor;

[0023] Figure 2 Fig. 3 is a schematic diagram of the oil film pressure distribution and wear area between the traditional crankshaft and the bearing;

[0024] Figure 3 Fig. 6 is a schematic diagram of the pump body assembly of the embodiment of the application;

[0025] Figure 4 Fig. 8 is a partial enlarged view of the crankshaft and the bearing of the embodiment of the application;

[0026] Figure 5 Fig. 10 is an oil film pressure distribution diagram between the crankshaft and the bearing of the embodiment of the application;

[0027] Figure 6 Fig. 12 is a comparison diagram of the oil film pressure of the embodiment of the application and the traditional structure;

[0028] Figure 7 Fig. 14 is a schematic diagram of the pump body assembly of another embodiment of the application.

[0029] The reference signs are as follows:

[0030] 1, crankshaft; 11, support section; 2, bearing; 21, groove; 3, cylinder; 4, sliding vane; 5, piston; 6, sealing piece; 61, groove; 7, elastic piece. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme of the application will be described clearly and completely below in combination with the specific embodiments of the application and the corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0032] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, unless the context clearly indicates otherwise. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," or "includes" and / or "including" when used in this specification, specify the presence of stated features, regions, steps, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, steps, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, the term "about" when used in connection with a numerical value, means that the value is within 10% of the recited value.

[0033] With reference to the drawings Figures 3 to 7 As shown, according to embodiments of the present application, a crankshaft assembly comprises:

[0034] a crankshaft 1 and a bearing 2, the crankshaft 1 being arranged in the bearing 2;

[0035] a seal 6 being arranged between the crankshaft 1 and the bearing 2, and being located at an end position of a supporting section 11 of the bearing 2 supporting the crankshaft 1 along an axial direction of the crankshaft 1.

[0036] The present application arranges a seal 6 at an axial end between the crankshaft 1 and the bearing 2, avoids direct contact between the crankshaft 1 and the bearing 2, greatly reduces leakage of lubricating oil at the axial end, improves oil film bearing pressure at the end region, makes the whole supporting section have good lubricating effect, reduces friction power consumption and wear, and makes the compressor run more smoothly and reduces noise caused by friction.

[0037] In some embodiments, the seal 6 is arranged at least two, respectively at two end positions of the supporting section 11 along the axial direction of the crankshaft 1.

[0038] Arranging the seal 6 at both end positions of the supporting section 11 can prevent direct contact between the crankshaft 1 and the bearing 2 at the two end positions, and can retain as much lubricating oil as possible between the crankshaft 1 and the bearing 2, improving the overall lubricating effect and reducing wear.

[0039] In some embodiments, the crankshaft 1 and / or the bearing 2 is provided with a groove 21, and part of the seal 6 is arranged in the groove 21.

[0040] Providing the groove 21 on the bearing 2 and / or the crankshaft 1 and arranging part of the seal 6 in the groove 21 improves the structural stability of the seal 6, prevents the seal 6 from being separated from the position between the bearing 2 and the crankshaft 1, and thus can ensure that the lubricating oil is retained between the crankshaft 1 and the bearing 2, maintaining the lubricating effect.

[0041] AsFigure 3 As shown, an annular groove 21 can be provided on the inner wall of the bearing 2 near the end portion, and an annular sealing element 6 is installed in the groove 21, and the inner wall of the sealing element 6 is in interference fit with the crankshaft 1. The sealing element 6 blocks the communication path between the gap space of the bearing 2 and the outside of the bearing 2, and does not introduce a new leakage channel.

[0042] As shown, or a groove 21 can be provided on the crankshaft 1, and a sealing element 6 is installed in the groove 21 of the crankshaft 1, and the outer wall of the sealing element 6 is in interference fit with the inner hole of the bearing 2. Similarly, the inner hole of the bearing 2 can be subjected to strengthening treatment (such as nitriding, DLC coating and other technical means) at least in the region matched with the sealing element 6, so that the surface hardness reaches more than 150% of the base material. Figure 7

[0043] The above two structures avoid direct contact between the crankshaft 1 and the bearing 2, greatly reduce the leakage of lubricating oil at the end portion of the bearing 2, improve the oil film bearing pressure in the two end regions of the bearing 2, significantly reduce the contact stress between the crankshaft 1 and the bearing 2, even eliminate direct contact, improve the wear of the crankshaft 1, and make the compressor run more smoothly, and reduce the noise caused by friction.

[0044] In some embodiments, the crankshaft assembly further comprises a resilient element 7, which is arranged in the groove 21 and contacts the sealing element 6, and the resilient element 7 applies elastic force to the sealing element 6, so that the sealing element 6 sealingly abuts against the outer circumferential surface of the crankshaft 1 or the inner circumferential surface of the bearing 2. Preferably, the sealing element 6 is in interference fit with the outer circumferential surface of the crankshaft 1 or the inner circumferential surface of the bearing 2, and the interference amount can be greater than 0.2 mm.

[0045] In this application, if the groove 21 is provided on the inner circumferential surface of the bearing 2, the resilient element 7 is made of rubber material, and an O-ring is preferred. If the groove 21 is provided on the outer circumferential surface of the crankshaft 1, the resilient element 7 adopts a tension ring structure.

[0046] The resilient element 7 is used to strengthen the sealing performance of the sealing element 6 and the crankshaft 1 or the bearing 2, to ensure that the oil film pressure of the lubricating oil between the crankshaft 1 and the bearing 2 is relatively stable, that is, the oil film pressure at both ends is not much different from the oil film pressure in the middle. In the traditional structure, the oil film pressure at both ends of the support portion is much smaller than the oil film pressure in the middle, such as Figure 5 ​The schematic diagram of the oil film pressure distribution within the compressor bearing 2 of this application shows that the oil film pressure is significantly higher than that of a conventional bearing 2 in the edge region of the support area. Therefore, the overall oil film support force of the bearing 2 of this application is significantly greater than that of a conventional bearing 2. Under the same crankshaft 1 load conditions, the contact force between the crankshaft 1 and the seal 6 of this application is significantly less than the contact force between the conventional crankshaft 1 and the bearing 2. In addition, the oil film friction coefficient of the former is significantly less than that of the metal-to-metal contact friction coefficient, resulting in a significant reduction in the frictional power loss of the crankshaft 1 and a substantial improvement in wear. At the same time, by eliminating the metal-to-metal contact between the crankshaft 1 and the bearing 2, this application makes the crankshaft 1 operate more smoothly and significantly reduces frictional noise.

[0047] like Figure 6 The comparison diagram shows that the compressor bearing 2 has a shaft diameter of 16mm and a bearing section length of 40mm, operating under the refrigeration capacity test conditions specified in national standard GB / T 15765. The average oil film bearing pressure of the present application's technical solution is 63% higher than that of the conventional solution. Under the same bearing area, the average oil film bearing pressure can characterize the magnitude of the oil film support force. Therefore, the oil film support force of bearing 2 in the present application is significantly improved compared to conventional bearing 2. Based on the above analysis, the present application fundamentally changes the oil film bearing characteristics of bearing 2, resulting in lower friction loss and higher reliability of the compressor bearing 2, with significant technical effects.

[0048] In some embodiments, the sealing element 6 is made of polytetrafluoroethylene mixed with a wear-resistant material, wherein the wear-resistant material accounts for 1-20% by mass. Preferably, the wear-resistant material includes at least one of copper powder, molybdenum disulfide, carbon fiber, and graphite.

[0049] In this application, the sealing element 6 is primarily made of PTFE (polytetrafluoroethylene) and blended with at least one friction-reducing and wear-resistant material such as copper powder, molybdenum disulfide, carbon fiber, and graphite. The elastic element 7 generates a clamping force between the sealing element 6 and the crankshaft 1. The blending of friction-reducing and wear-resistant materials into the sealing element 6 significantly reduces the frictional power consumption caused by this clamping force and extends the service life of the sealing element 6. The mass content of each wear-resistant material is as follows: copper powder 2-5%, molybdenum disulfide 5-10%, carbon fiber 10-20%, and graphite 1-3%.

[0050] In some embodiments, the crankshaft 1 is nitrided at least in the area that contacts the seal 6.

[0051] The crankshaft 1 base material is ductile iron, and at least the area mating with the seal 6 is nitrided to make its surface hardness more than 1.5 times that of the base material. These characteristics give the crankshaft 1 and the seal 6 excellent friction performance. Under the same stress conditions, the friction power consumption and wear between the crankshaft 1 and the seal 6 are significantly lower than those of the conventional crankshaft 1-bearing 2 friction pair.

[0052] In some embodiments, the width of the groove 21 is set as Bc, and the width of the seal 6 is set as Bf, along the axial direction of the crankshaft 1, satisfying 0 < Bc-Bf < 0.15 mm. Preferably, the seal 6 is provided with a groove 61 on the side surface of the crankshaft 1 or the bearing 2.

[0053] The height difference between the groove 61 height Bc and the seal 6 end surface height Bf is less than 0.15 mm in the free state of the seal 6. The groove 61 is provided on the abutting side surface of the seal 6, and can store part of the lubricating oil, preventing dry friction between the seal 6 and the bearing 2 or the crankshaft 1.

[0054] According to another aspect of the present application, there is provided a pump body assembly comprising the crankshaft assembly as described above.

[0055] According to still another aspect of the present application, there is provided a rotary compressor comprising the crankshaft assembly as described above or the pump body assembly as described above.

[0056] The crankshaft assembly or the pump body assembly described above can be applied to various types of compressors such as scroll compressors, sliding vane compressors, rotary vane compressors, etc. in addition to rotary compressors.

[0057] It is easily understood by those skilled in the art that the above-mentioned embodiments can be freely combined and superimposed without conflict.

[0058] The above description is merely preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above description is merely preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A rotary compressor, characterized in that, The pump body assembly includes a crankshaft assembly, a cylinder (3), a vane (4), and a piston (5). The crankshaft assembly includes a crankshaft (1) and a sliding bearing (2). The crankshaft (1) includes a straight shaft and an eccentric portion. The crankshaft (1) passes through the sliding bearing (2), and the sliding bearing (2) is located above the eccentric portion. The inner wall of the sliding bearing (2) extends axially along the crankshaft (1) to form a support area for the crankshaft (1). A seal (6) is provided between the crankshaft (1) and the bearing (2), and is located at the end of the support section (11) of the sliding bearing (2) supporting the crankshaft (1) along the axial direction of the crankshaft (1); at least two seals (6) are provided, respectively located at both ends of the support section (11) along the axial direction of the crankshaft (1); The crankshaft (1) and / or the sliding bearing (2) are provided with grooves (21), and part of the seal (6) is fitted into the grooves (21).

2. The rotary compressor according to claim 1, characterized in that, The crankshaft assembly also includes an elastic element (7), which is disposed in the groove (21) and contacts the seal (6). The elastic element (7) applies the elastic force of the seal (6) so that the seal (6) seals against the outer peripheral surface of the crankshaft (1) or the inner peripheral surface of the bearing (2).

3. The rotary compressor according to claim 2, characterized in that, The seal (6) is interference-fitted with the outer circumferential surface of the crankshaft (1) or the inner circumferential surface of the bearing (2).

4. The rotary compressor according to any one of claims 1-3, characterized in that, The sealing element (6) is made of polytetrafluoroethylene mixed with wear-resistant material, and the mass content of the wear-resistant material is 1-20%.

5. The rotary compressor according to claim 4, characterized in that, The wear-resistant material includes at least one of copper powder, molybdenum disulfide, carbon fiber, and graphite.

6. The rotary compressor according to claim 5, characterized in that, The crankshaft (1) is nitrided at least in the area that contacts the seal (6).

7. The rotary compressor according to claim 1, characterized in that, Along the axial direction of the crankshaft (1), the width of the groove (21) is set to Bc, and the width of the seal (6) is set to Bf, satisfying 0 <Bc-Bf<0.15mm。 8. The rotary compressor according to claim 1, characterized in that, The seal (6) has a groove (61) on the side that abuts against the crankshaft (1) or the bearing (2).

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