A bearing for a fluid pump

Abstract

The present invention provides a bearing for a fluid pump. When the fluid pump is working, a positive pressure area (28) for fluid pumping out and a negative pressure area (27) for fluid inflow are formed in the fluid pump. A fluid supply groove (253) and a fluid return groove (254) extending in the axial direction are respectively formed on the wall of the shaft hole (26) of the bearing (25). The fluid supply groove (253) is connected to the positive pressure area (28), and the fluid return groove (254) is connected to the negative pressure area (27). Moreover, the fluid supply groove (253) is in the shape of a blind groove. The present invention can reduce the clamping force of the oil seal, or directly omit the oil seal, thereby reducing the manufacturing cost of the oil pump.

Description

Technical Field

[0001] The present invention relates to a fluid pump, and in particular to a bearing used in a fluid pump. Background Art

[0002] When a fluid pump, such as an oil pump, is working, the rotor inside the oil pump rotates at high speed. In order to reduce the friction between the rotating shaft and the wall of the shaft hole of the pump body, that is, the sliding bearing, the contact part must be lubricated.

[0003] Chinese Patent Application Publication CN105298837A discloses a technical solution for lubricating a sliding bearing, which achieves lubrication of the sliding bearing by forming an oil passage.

[0004] However, although the above technical solution realizes the lubrication of the sliding bearing with a relatively simple structure and relatively low cost, in order to prevent the lubricating oil from flowing out of the pump along the motor shaft, a sealing component needs to be provided between the pump housing and the motor shaft, and in order to ensure good sealing performance, a certain clamping force is required between the motor shaft and the sealing component. On the one hand, this increases the starting torque of the oil pump, resulting in an increase in the failure rate of starting, an increase in the loss of the oil pump, and a decrease in efficiency; on the other hand, the sealing component must be made of a more wear-resistant material, resulting in an increase in the cost of raw materials. The above problems will eventually reduce the market competitiveness of the product. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a bearing for a fluid pump, which can lubricate the rotating shaft and prevent leakage of the lubricating medium, while also reducing the torque required for starting the fluid pump and the energy consumed during operation.

[0006] To achieve the above-mentioned purpose and other related purposes, the present invention provides a bearing for a fluid pump. When the fluid pump is working, a positive pressure zone for fluid pumping out and a negative pressure zone for fluid flowing in are formed in the fluid pump, and a fluid supply groove and a fluid return groove extending along the axial direction are respectively formed on the wall of the axial hole of the bearing, wherein the fluid supply groove is connected to the positive pressure zone, the fluid return groove is connected to the negative pressure zone, and the fluid supply groove is in the shape of a blind groove.

[0007] A technical solution of the present invention is a bearing for a fluid pump. When the fluid pump is working, a positive pressure zone for fluid pumping out and a negative pressure zone for fluid reflow are formed in the fluid pump. A fluid supply groove extending in the axial direction, a fluid reflow groove and a fluid storage groove extending in the circumferential direction are respectively formed on the axial hole wall of the bearing, wherein the fluid supply groove is connected to the positive pressure zone, the fluid reflow groove is connected to the negative pressure zone, and the fluid supply groove is in the shape of a blind groove, and one end of the fluid reflow groove is connected to the fluid storage groove.

[0008] In another technical solution of the present invention, a bearing for a fluid pump is provided, wherein the fluid supply groove and the fluid return groove are arranged in a negative pressure area where a lubricating film is formed in the shaft hole when the fluid pump is working.

[0009] In another technical solution of the present invention, the bearing of the fluid pump, the fluid supply groove and the fluid return groove are respectively arranged on both sides of the main load received by the fluid pump when the fluid pump is working.

[0010] Another technical solution of the present invention is a bearing of a fluid pump. When the fluid pump is working, the shaft of the fluid pump is driven to rotate in the shaft hole. In the rotation direction of the shaft, the fluid reflux groove is located in the area on the side of the positive pressure area leaving the lubricating film, and the fluid supply groove is located in the area on the side of the positive pressure area entering the lubricating film, and the angle from the fluid reflux groove to the fluid supply groove is greater than or equal to 30° and less than or equal to 180°, preferably greater than or equal to 60° and less than or equal to 160°, and further preferably greater than or equal to 90° and less than or equal to 140°.

[0011] In a bearing of a fluid pump according to another aspect of the present invention, the fluid supply groove is provided near a location where the thickness of the lubricating film is maximum.

[0012] In a bearing of a fluid pump according to another embodiment of the present invention, in the axial direction, a ratio of a length of the fluid supply groove to a length of the shaft hole is greater than or equal to 0.5 and less than or equal to 0.95.

[0013] In a bearing of a fluid pump according to another technical solution of the present invention, the flow channel area of ​​the fluid supply groove is larger than the flow channel area of ​​the fluid return groove.

[0014] As described above, in the bearing for the fluid pump of the present invention, a fluid supply groove and a fluid return groove extending in the axial direction are respectively formed on the wall of the shaft hole, the fluid supply groove is connected to the positive pressure area, the fluid return groove is connected to the negative pressure area, and the fluid supply groove is a blind groove. This structure allows the fluid from the positive pressure area to be pumped from the fluid supply groove into the shaft hole to lubricate the shaft and the shaft hole, and the fluid flowing to the outside of the pump body is sucked back to the negative pressure area through the fluid return groove, which not only achieves the purpose of lubricating the sliding bearing, but also reduces the leakage of the fluid to the outside of the pump body, and can also take away impurities, sludge and friction debris together with the lubricating oil through the fluid return groove to prevent them from accumulating at the shaft hole and causing wear to various moving parts.

[0015] At the same time, since the amount of fluid leakage to the outside of the pump body is reduced, the pressure accumulation of the fluid at the oil seal can be reduced, and the clamping force required for the oil seal to achieve sealing can be reduced, thereby achieving the effect of reducing the friction torque when the fluid pump rotates and increasing the success rate of fluid pump startup, thereby improving the reliability of the product and reducing the wear of the oil seal lip and the rotating shaft.

[0016] As mentioned above, since the pressure of the sealed fluid is reduced, the holding force of the oil seal can be reduced, so a low-grade oil seal can be selected. The lower the grade of the oil seal, the lower the price. Selecting a low-grade oil seal can reduce the overall manufacturing cost of the fluid pump. At the same time, the pump shaft and oil seal can use cheap raw materials to reduce the cost of raw materials, especially when produced in large quantities, the cost reduction is more obvious.

[0017] According to another technical solution of the present invention, a fluid supply groove and a fluid return groove extending in the axial direction and a fluid storage groove extending in the circumferential direction are provided on the hole wall of the shaft hole, and the fluid supply groove is a blind groove, one end of the fluid return groove is connected with the fluid storage groove, the fluid from the positive pressure zone is pumped from the fluid supply groove into the shaft hole to lubricate the shaft and the shaft hole, and then the fluid flowing to the outside of the pump body is stored in the fluid storage groove and sucked back to the negative pressure zone through the fluid return groove, which not only achieves the purpose of lubricating the shaft and the shaft hole, but also can effectively prevent the fluid from leaking to the outside of the pump body, so that the oil seal parts can be omitted, and then the oil seal pressing process can be omitted, and the overall manufacturing cost of the pump is lower. At the same time, due to the absence of the oil seal, the rotating shaft of the fluid pump is no longer subject to the friction of the oil seal lip, which reduces the friction torque when the pump is running, has lower operating energy consumption, and can also reduce the axial height of the bearing in the pump body, thereby realizing the overall miniaturization of the product. In addition, the fluid storage groove is set up so that the fluid flowing out in the axial direction can be gathered there and lose pressure. At the same time, impurities such as sludge and friction chips can be temporarily stored and collected, and can be taken away together with the lubricating oil through the fluid reflux groove to prevent them from accumulating in the shaft hole and causing wear to the moving parts.

[0018] According to another technical solution of the present invention, the fluid supply groove and the fluid return groove are arranged in the negative pressure area where the lubricating film is formed in the shaft hole when the fluid pump is working, which is conducive to forming a stable lubricating film between the shaft and the shaft hole.

[0019] According to another technical solution of the present invention, the fluid supply groove and the fluid return groove are respectively arranged on both sides of the main load received by the fluid pump when working, which is further conducive to forming a stable lubricating film between the shaft and the shaft hole.

[0020] According to another technical solution of the present invention, the fluid reflow groove is located in the area on the side of the positive pressure area leaving the lubricating film, the fluid supply groove is located in the area on the side of the positive pressure area entering the lubricating film, and the angle from the fluid reflow groove to the fluid supply groove is greater than or equal to 30° and less than or equal to 180°, which is more conducive to forming a stable lubricating film between the shaft and the shaft hole.

[0021] According to another technical solution of the present invention, when the fluid supply groove is located near the point where the film thickness of the lubricating film is the largest, it is the best position to form a stable lubricating film between the shaft and the shaft hole.

[0022] According to another technical solution of the present invention, in the axial direction, the ratio of the length of the fluid supply groove to the length of the shaft hole is greater than or equal to 0.5 and less than or equal to 0.95, preferably greater than or equal to 0.6 and less than or equal to 0.9, which can not only lubricate the shaft and the shaft hole well, but also effectively prevent leakage of the fluid. According to another technical solution of the present invention, the flow channel area of ​​the fluid supply groove is greater than the flow channel area of ​​the fluid return groove, which is conducive to forming a stable lubricating film with good supporting force. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is an exploded view of an electric oil pump according to an embodiment of the present invention.

[0024] Figure 2 The figure shows a front view of a pump body according to a first embodiment of the present invention.

[0025] Figure 3 Display as Figure 2 AA section view.

[0026] Figure 4 Shown is a diagram of the working principle of a trochoid pump.

[0027] Figure 5 A cross-sectional view of a pump body according to a second embodiment of the present invention is shown.

[0028] Figure 6 A schematic diagram showing the dynamic pressure lubrication in the shaft hole of the bearing of the present invention. DETAILED DESCRIPTION

[0029] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0030] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0031] In this embodiment, the fluid pump takes the electric oil pump 100 as an example. Figure 1 , Figure 1An exploded view of an electric oil pump 100 according to the present invention is shown.

[0032] like Figure 1 As shown, the electric oil pump 100 is provided with a base 1, a pump body 2, a motor 3 providing driving force and a rear cover 4 from bottom to top, and the base 1, the pump body 2, the motor 3 providing driving force and the rear cover 4 are fixedly connected in sequence by fasteners, and the fasteners can be screws, bolts or pins. The bottom of the base 1 is connected to the gearbox or the engine ( Figure 1 The base 1 is connected to an application object (not shown), and an oil inlet hole 11 and an oil outlet hole 12 are formed through the upper and lower end surfaces of the base 1. When the electric oil pump 100 is working, the motor 3 is started, and the electric oil pump 100 will suck the oil in the gearbox from the oil inlet hole 11 and pump it out from the oil outlet hole 12 after pressurizing it.

[0033] The first embodiment of the present invention is shown in Figure 2 and Figure 3 , Figure 2 A front view of the pump body in the first embodiment is given, Figure 3 Given Figure 2 AA sectional view, for the convenience of viewing, the section is not hatched. Figure 2-Figure 3 As shown, the pump body 2 includes a pump body 24 and a bearing 25. A chamber 23 is provided on the pump body 24. An outer rotor 21 and an inner rotor 22 meshing with the outer rotor 21 are assembled in the chamber 23. Figure 2 In the embodiment, a positive pressure area 28 and a negative pressure area 27 are provided on the axial end surface 231 of the chamber 23 .

[0034] It should be noted that Figure 1 The electric oil pump 100 in the embodiment is a cycloid pump. The working principle of the cycloid pump is as follows: Figure 4 As shown, the inner rotor 22 and the outer rotor 21 are internally meshed, and the inner rotor 22 has 6 external teeth. Correspondingly, the outer rotor 21 has 7 internal teeth. The inner rotor 22 rotates clockwise in the direction shown in the figure, and each external tooth of the inner rotor 22 meshes with a different part of the internal tooth of the outer rotor 21. The 7 inter-tooth spaces formed between the inner rotor 22 and the outer rotor 21 are Figure 4The middle teeth 224 and teeth 225, teeth 225 and teeth 226, teeth 226 and teeth 221 respectively form three inter-tooth spaces with the outer rotor 21, and the volume of each inter-tooth space changes from large to small. The left side of the inner rotor 22 forms an oil pressure chamber 281, an oil pressure chamber 282 and an oil pressure chamber 283, respectively. The oil pressure chamber 281, the oil pressure chamber 282 and the oil pressure chamber 283 are respectively connected to the positive pressure area 28 on the pump body 2; the teeth 221 and teeth 222, the teeth 222 and teeth 223, and the teeth 223 and teeth 224 respectively form three inter-tooth spaces with the outer rotor 21, and the volume of each inter-tooth space changes from small to large. The right side of the inner rotor 22 forms an oil suction chamber 271, an oil suction chamber 272 and an oil suction chamber 273, respectively. The oil suction chamber 272 and the oil suction chamber 273 are connected to the negative pressure area 27 on the pump body 2. Among them, the negative pressure area 27 is connected to the oil suction chamber 271, the oil suction chamber 272 and the oil suction chamber 273, and the positive pressure area 28 is connected to the oil pressure chamber 281, the oil pressure chamber 282 and the oil pressure chamber 283. As the inner rotor 22 rotates in the direction shown in the figure, the oil in the oil suction chamber 273, the oil suction chamber 272 and the oil suction chamber 271 is sequentially sent from the negative pressure area 27 to the positive pressure area 28.

[0035] Furthermore, if Figure 3 As shown, the bearing 25 has an axial hole 26, one side of which is open to communicate with the chamber 23, and the motor shaft 33 is inserted into the axial hole 26 and connected to the inner rotor 22. The motor shaft 33 is connected to the motor rotor 32. When the motor 3 is started, the motor shaft 33 drives the inner rotor 22 to rotate, and the bearing 25 of the pump body 2 constitutes a sliding bearing of the motor shaft 33. A groove 29 for placing a sealing member such as an oil seal 5 is provided at the end of the bearing 25 away from the chamber 23, and the bottom of the groove 29 is communicated with the axial hole 26. In order to ensure lubrication between the motor shaft 33 and the wall of the shaft hole 26, in this embodiment, a fluid supply groove 253 extending in the axial direction is provided on the wall of the shaft hole 26, and the fluid supply groove 253 is in the shape of a blind groove, and its open end is connected to the chamber 23; a fluid reflux groove 254 extending in the axial direction is also provided on the wall of the shaft hole 26, and the fluid reflux groove 254 is connected to the chamber 23 and passes through the wall of the shaft hole 26. Specifically, according to Figure 3 The fluid reflux groove 254 is connected to the groove 29 for placing the oil seal 5. A fluid supply flow path 251 and a fluid reflux flow path 252 are also provided on the axial end surface 231 of the chamber 23. The fluid supply flow path 251 is connected to the positive pressure area 28 and the fluid supply groove 253, and the fluid reflux flow path 252 is connected to the negative pressure area 27 and the fluid reflux groove 254.

[0036] The positive pressure zone 28 is connected to the fluid supply groove 253 through the fluid supply path 251, supplies oil to the shaft hole 26, and lubricates the motor shaft 33 and the shaft hole 26; the negative pressure zone 27 is connected to the fluid return groove 254 through the fluid return path 252, draws oil back from the shaft hole 26, and prevents the lubricating oil from flowing out along the motor shaft 33 to the outside of the pump body 2.

[0037] It should be noted that when the oil in the positive pressure zone 28 is pumped into the gap between the motor shaft 33 and the wall of the shaft hole 26 along the fluid supply groove 253, since the fluid supply groove 253 is in the shape of a blind groove, the oil can only flow to the closed end of the fluid supply groove 253 when entering. At this time, the closed end of the fluid supply groove 253 acts as an interception, making it difficult for the oil in the fluid supply groove 253 to flow into the motor 3.

[0038] In addition, the fluid reflux groove 254 can also clean the sliding bearing, taking away impurities, sludge and friction debris together with the lubricating oil, preventing them from accumulating in the shaft hole 26 and causing wear to the moving parts, thereby causing the electric oil pump 100 to malfunction.

[0039] Furthermore, in this embodiment, the bottom of the groove 29 for placing the oil seal 5 is connected to the shaft hole 26, but the groove 29 is not connected to the fluid supply groove 253. During assembly, the oil seal 5 is sleeved on the motor shaft 33, and there is a certain clamping force between the oil seal 5 and the motor shaft 33. It should be noted that since the fluid supply groove 253 is not directly connected to the groove 29 where the oil seal 5 is located, at the same time, the oil in the shaft hole 26 and the oil collected at the groove 29 will be sucked back into the negative pressure area 27 by the fluid reflux groove 254, so the oil pressure accumulated at the oil seal 5 will be reduced. Since the oil pressure to be blocked is reduced, the clamping force of the oil seal 5 can be reduced, thereby achieving the effect of reducing the friction torque when the electric oil pump 100 rotates and improving the success rate of starting the electric oil pump 100. In addition, the energy consumption during operation can be reduced, and the efficiency of the electric oil pump 100 is improved. At the same time, since the wear of the oil seal lip and the shaft is reduced, the reliability of the product can be improved.

[0040] Since the oil pressure that needs to be sealed is reduced, the clamping force of the oil seal 5 can be reduced, so that a low-grade oil seal can be selected for the oil seal 5. The lower the grade of the oil seal 5, the lower the price. Selecting a low-grade oil seal 5 can reduce the overall manufacturing cost of the electric oil pump 100. At the same time, the motor shaft 33 and the oil seal 5 can use cheap raw materials, thereby reducing the cost of raw materials. Especially when produced in large quantities, the cost reduction is more obvious.

[0041] Figure 5 A cross-sectional view of the pump body in the second embodiment is given. For the sake of convenience, the cross-section is not hatched. Figure 5 As shown, the present embodiment is different from the first embodiment in that: 1. Instead of the groove 29 for the oil seal 5, a fluid storage groove 255 extending in the circumferential direction is provided on the hole wall of the shaft hole 26; 2. One end of the fluid reflux groove 254' extending in the axial direction on the hole wall of the shaft hole 26 is connected to the chamber 23, and the other end is connected to the fluid storage groove 255.

[0042] The fluid storage groove 255 can make the oil flowing along the axial direction of the motor shaft 33 gather there and lose its pressure. At the same time, impurities such as sludge and friction chips can be temporarily stored there to prevent them from causing damage to the moving parts.

[0043] The positive pressure area 28 is connected to the fluid supply groove 253 through the fluid supply flow path 251, and supplies oil to the shaft hole 26 to lubricate the motor shaft 33 and the shaft hole 26; the negative pressure area 27 is connected to the fluid return groove 254' through the fluid return flow path 252, and the lubricating oil on the hole wall of the shaft hole 26 and gathered in the fluid storage groove 255 is drawn back to the negative pressure area 27 through the fluid return groove 254', thereby blocking the oil from flowing in the axial direction and leaking to the outside of the pump body 2. On the other hand, impurities such as sludge and friction debris temporarily stored in the fluid storage groove 255 can be drawn back to the negative pressure area 27 through the fluid return groove 254' to ensure the cleanliness of the sliding bearing oil circuit.

[0044] In this embodiment, after the fluid storage tank 255 is provided, the oil will no longer flow out of the pump body 2. At this time, the oil seal 5 parts can be omitted, thereby eliminating the oil seal 5 and the pressing process of the oil seal 5. The overall manufacturing cost of the electric oil pump 100 is lower. At the same time, due to the absence of the oil seal 5, the motor shaft 33 is no longer subject to the friction of the oil seal lip, which reduces the friction torque of the electric oil pump 100 when the shaft rotates, and has lower operating energy consumption. In addition, the axial height of the pump body 2 can also be reduced, thereby achieving the effect of miniaturizing the overall product.

[0045] In the first and second embodiments, the fluid supply flow path 251 connects the fluid supply groove 253 and the positive pressure area 28; the fluid return flow path 252 connects the fluid return grooves 254, 254' and the negative pressure area 27. During the operation of the electric oil pump 100, the motor shaft 33 will be affected by the main load. During the rotation of the motor 3, the dynamic action of the oil contacted by the motor shaft 33 forms a wedge-shaped liquid film to generate oil wedge pressure to balance the main load. Among them, the main load can be the rotating part of the electric oil pump 100, such as the gravity of the inner rotor 22, the motor shaft 33, the motor rotor and the magnetic steel, and the radial thrust of the oil pressure on the inner rotor 22.

[0046] like Figure 6 As shown, the motor shaft 33 rotates in the manner shown in the figure, and the motor shaft 33 is subjected to a main load F in the direction shown in the figure. Figure 6 The lubricating oil film formed by the motor shaft 33 rotating in the shaft hole is shown. Figure 6 According to the principle of fluid dynamic lubrication, the shaded part in the figure is the load-bearing area of ​​the lubricating oil film. The load-bearing area is the positive pressure area of ​​the oil film, and the other parts except the load-bearing area are the negative pressure areas of the oil film.

[0047] To ensure that the oil in the positive pressure area 28 can be continuously pumped into the shaft hole 26, further, the fluid supply groove 253 and the fluid return grooves 254, 254' are arranged in the negative pressure area where the lubricating film is formed in the shaft hole 26 when the pump body 2 is working. In this embodiment, the fluid supply flow path 251 and the fluid return flow path 252 are arranged on both sides of the main load F that the pump body 2 is subjected to when working. Figure 6 The setting areas of the fluid supply groove 253 and the fluid return groove 254, 254' are given as area E and area D respectively, that is, the fluid supply groove 253 is set in area E on the side of the positive pressure area entering the lubricating film, and the fluid return groove 254, 254' is set in area D on the side of the positive pressure area leaving the lubricating film.

[0048] Preferably, the angle α from the fluid reflux groove 254, 254' to the fluid supply groove 253 is greater than or equal to 30° and less than or equal to 180°. If the angle α is less than 30°, the oil may be directly drawn away from the fluid reflux groove 254, 254' from the fluid supply groove 253 into the shaft hole 26, which is not conducive to the formation of a lubricating film. If the angle α is greater than 180°, the fluid supply groove 253 and / or the fluid reflux groove 254, 254' will approach the positive pressure area of ​​the lubricating film, destroying the formation of the positive pressure area of ​​the lubricating film. More preferably, the angle α is greater than or equal to 60° and less than or equal to 160°. A more preferred solution is to make the angle α greater than or equal to 90° and less than or equal to 140°.

[0049] It is further preferred to arrange the fluid supply groove 253 near the maximum thickness of the lubricating film, that is, near the maximum gap between the shaft and the shaft hole. In this case, both lubrication and leakage prevention can be taken into account to achieve good results.

[0050] In addition, if the axial length of the fluid supply groove 253 is too short, a part of the shaft will not be fully lubricated, and if it is too long, it will easily increase the leakage of oil along the axial direction, which is not only not conducive to the lubrication of the shaft, but also reduces the overall efficiency of the oil pump. In the present invention, the ratio of the axial length of the fluid supply groove 253 to the length of the shaft hole 26 is greater than or equal to 0.5 and less than or equal to 0.95, preferably greater than or equal to 0.6 and less than or equal to 0.9.

[0051] Furthermore, in order to form a stable lubricating film with good supporting effect in the shaft hole 26, the flow channel area of ​​the fluid supply groove 253 should be larger than the flow channel area of ​​the fluid return grooves 254 and 254'.

[0052] Next, the operation process of the present invention constructed as described above will be described.

[0053] Assume that Figure 6The motor shaft 33 shown is subjected to the main load F. The motor shaft 33 of the motor 3 drives the inner rotor 22 to rotate, and then the inner rotor 22 drives the outer rotor 21 to rotate. As a result, the oil is sucked into the negative pressure area 27 from the oil inlet hole 11, and then pumped into the positive pressure area 28 and then pumped out from the oil outlet hole 12. In this process, due to the positive pressure in the positive pressure area 28, the oil in the positive pressure area 28 is pumped into the fluid supply groove 253 through the fluid supply flow path 251. During the rotation of the motor shaft 33, the oil in the fluid supply groove 253 is brought into the gap between the motor shaft 33 and the shaft hole 26 of the pump body 2, wrapping the outer peripheral surface of the motor shaft 33, and then refluxed into the negative pressure area 27 from the fluid reflux grooves 254 and 254'.

[0054] With respect to the first embodiment, during the rotation of the motor shaft 33, a small amount of lubricating oil flows along the motor shaft 33 toward the oil seal 5. Due to the existence of the oil seal 5, the small amount of lubricating oil is blocked. At the same time, since the fluid reflux groove 254 is connected with the groove 29, the oil at the oil seal 5 is sucked back into the fluid reflux groove 254, ensuring that there is no oil pressure at the oil seal 5 that causes the oil to flow out of the pump body 2.

[0055] With respect to the second embodiment, during the rotation of the motor shaft 33, the lubricating oil flowing along the motor shaft 33 toward the outside of the pump body 2 is collected in the fluid storage groove 255 and loses pressure, and is sucked back into the negative pressure area 27 through the fluid reflux groove 254', thereby eliminating the oil seal 5 and the press-fitting process of the oil seal 5, greatly reducing the overall manufacturing cost of the electric oil pump 100, and also shortening the electric oil pump 100 in the axial direction by the thickness corresponding to the setting of the oil seal, thereby realizing miniaturization of the product.

[0056] Although the above description is made by taking the electric oil pump 100 as an example, a person skilled in the art should understand that the present invention is not limited to the electric oil pump 100, and may also be any fluid pump such as a water pump, an air pump, etc. In addition, although the present invention is described by taking the cycloid pump as an example, a person skilled in the art should understand that the present invention is not limited to the cycloid pump, and may also be any pump such as a vane pump, a plunger pump, other gear pumps, etc., as long as a positive pressure area for the fluid to be pumped out and a negative pressure area for the fluid to flow in are formed in the fluid pump when the fluid pump is working. In addition, the bearing may also be separate from the pump body and fixed to the pump body by installation.

[0057] In summary, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A bearing for a fluid pump, wherein when the fluid pump is in operation, a positive pressure area (28) for fluid to be pumped out and a negative pressure area (27) for fluid to flow in are formed in the fluid pump, wherein the bearing (25) is characterized in that a fluid supply groove (253) and a fluid return groove (254) extending in the axial direction are respectively formed on the wall of the shaft hole (26) of the bearing (25), wherein: The fluid supply groove (253) is connected to the positive pressure zone (28) via a fluid supply flow path (251), and the fluid return groove (254) is connected to the negative pressure zone (27) via a fluid return flow path (252). The fluid supply groove (253) is a blind groove having an open end and a closed end, and the open end is connected to the positive pressure zone (28); The fluid is sucked into the negative pressure zone (27) and pumped into the positive pressure zone (28). Under the action of the positive pressure in the positive pressure zone (28), the fluid in the positive pressure zone (28) is pumped into the fluid supply groove (253) through the fluid supply flow path (251). The fluid in the fluid supply groove (253) is brought into the gap between the shaft and the shaft hole (26) during the rotation of the shaft, and then flows back to the negative pressure zone (27) from the fluid reflux groove (254).

2. A bearing for a fluid pump, wherein when the fluid pump is in operation, a positive pressure area (28) for pumping out the fluid and a negative pressure area (27) for returning the fluid are formed in the fluid pump, wherein the bearing (25) is characterized in that a fluid supply groove (253) extending in the axial direction, a fluid return groove (254') and a fluid storage groove (255) extending in the circumferential direction are respectively formed on the wall of the axial hole (26) of the bearing (25), wherein: The fluid supply groove (253) is connected to the positive pressure area (28) through the fluid supply flow path (251), and the fluid return groove (254') is connected to the negative pressure area (27) through the fluid return flow path (252), and the fluid supply groove (253) is a blind groove with an open end and a closed end, and the open end is connected to the positive pressure area (28), and one end of the fluid return groove (254') is connected to the fluid storage groove (255); The fluid is sucked into the negative pressure zone (27) and pumped into the positive pressure zone (28). Under the action of the positive pressure in the positive pressure zone (28), the fluid in the positive pressure zone (28) is pumped into the fluid supply groove (253) through the fluid supply flow path (251). The fluid in the fluid supply groove (253) is brought into the gap between the shaft and the shaft hole (26) during the rotation of the shaft, and then flows back to the negative pressure zone (27) from the fluid reflux groove (254').

3. The bearing of a fluid pump according to claim 1 or 2, characterized in that: The fluid supply groove (253) and the fluid return groove (254, 254') are arranged in a negative pressure area that forms a lubricating film in the shaft hole (26) when the fluid pump is working.

4. The bearing of a fluid pump according to claim 3, characterized in that: The fluid supply groove (253) and the fluid return groove (254, 254') are respectively arranged on both sides of the main load (F) to which the fluid pump is subjected when working.

5. The bearing for a fluid pump according to claim 4, characterized in that: When the fluid pump is working, the shaft driving the fluid pump rotates in the shaft hole (26), and in the rotation direction of the shaft, the fluid return groove (254, 254') is located in the area (D) on the side of the positive pressure area leaving the lubricating film, and the fluid supply groove (253) is located in the area (E) on the side of the positive pressure area entering the lubricating film, and the angle (α) from the fluid return groove (254, 254') to the fluid supply groove (253) is greater than or equal to 30° and less than or equal to 180°.

6. The bearing of a fluid pump according to claim 5, characterized in that: The fluid supply groove (253) is arranged near the location where the film thickness of the lubricating film is maximum.

7. The bearing for a fluid pump according to any one of claims 1 to 6, characterized in that: In the axial direction, the ratio of the length of the fluid supply groove (253) to the length of the shaft hole (26) is greater than or equal to 0.5 and less than or equal to 0.

95.

8. The bearing for a fluid pump according to any one of claims 1 to 6, characterized in that: The flow channel area of ​​the fluid supply groove (253) is greater than the flow channel area of ​​the fluid return groove (254, 254').

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