CN210978222U - Bearing for fluid pump - Google Patents

Abstract

The utility model provides a bearing for fluid pump, when fluid pump during operation be formed with positive pressure district (28) that supply fluid to pump out in the fluid pump to and supply negative pressure district (27) that the fluid flows in be formed with along axially extended fluid supply groove (253) and first fluid backward flow groove (254) or second fluid backward flow groove (254 ') on shaft hole (26) pore wall of bearing (25) respectively, wherein, fluid supply groove (253) with positive pressure district (28) intercommunication, first fluid backward flow groove (254) or second fluid backward flow groove (254') with negative pressure district (27) intercommunication, and, fluid supply groove (253) are blind groove form. The utility model discloses can reduce the power of holding tightly of oil blanket, or directly save the oil blanket, reduce the manufacturing cost of oil pump.

Description

Bearing for fluid pump

Technical Field

The present invention relates to a fluid pump, and more particularly, to a bearing for a fluid pump.

Background

When a fluid pump, such as an oil pump, is operated, a rotor in the oil pump rotates at a high speed, and in order to reduce friction between the rotating shaft and the hole wall of the shaft hole of the pump body, i.e., a sliding bearing, the contact part must be lubricated.

Chinese patent application publication CN105298837A discloses a technique for lubricating a sliding bearing by forming an oil passage.

However, although the above-described technical solution achieves lubrication of the sliding bearing with a relatively simple structure and at a relatively low cost, in order to prevent the lubricating oil from flowing out to the outside of the pump along the motor shaft, a seal member needs to be provided between the pump housing and the motor shaft, and in order to ensure good sealing performance, a certain amount of sealing is required between the motor shaft and the seal memberHolding deviceOn one hand, the starting torque of the oil pump is increased, so that the starting failure rate is increased, the loss of the oil pump is increased, and the efficiency is reduced; on the other hand, the sealing member must be made of a more wear-resistant material, which increases the raw material cost. The above problems eventually lead to a reduction in the market competitiveness of the product.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a bearing for a fluid pump, which can lubricate a rotating shaft and prevent leakage of a lubricating medium, and at the same time, can reduce torque required when the fluid pump is started and energy consumed when the fluid pump is operated.

To achieve the above and other related objects, there is provided a bearing for a fluid pump in which a positive pressure region for pumping out a fluid and a negative pressure region for flowing in the fluid are formed when the fluid pump is operated,

and a fluid supply groove and a first fluid return groove which extend along the axial direction are respectively formed on the hole wall of the shaft hole of the bearing, wherein the fluid supply groove is communicated with the positive pressure region, the first fluid return groove is communicated with the negative pressure region, and the fluid supply groove is in a blind groove shape.

In an embodiment of the present invention, the fluid supply groove and the first fluid backflow groove are disposed in a negative pressure region where a lubrication film is formed in the shaft hole when the fluid pump operates.

In an embodiment of the present invention, the fluid supply tank and the first fluid return tank are respectively disposed on two sides of a main load (F) applied to the fluid pump during operation.

In an embodiment of the present invention, when the fluid pump operates, the shaft of the fluid pump is driven to rotate in the shaft hole, in the rotation direction of the shaft, the first fluid return channel is located in the region D on one side of the positive pressure region away from the lubricating film, the fluid supply channel is located in the region E on one side of the positive pressure region entering the lubricating film, and the included angle (α) from the first fluid return channel 254 to the fluid supply channel is greater than or equal to 30 ° and less than or equal to 180 °.

In an embodiment of the present invention, the fluid supply groove is disposed near a position where a thickness of the lubricating film is maximum.

In an embodiment of the present invention, 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 in the axial direction.

In an embodiment of the present invention, the flow area of the fluid supply tank (253) is larger than the flow area of the first fluid return tank 254.

The utility model also provides a bearing for fluid pump, work as fluid pump during operation be formed with the positive pressure district that supplies the fluid to pump in the fluid pump to and the negative pressure district that supplies the fluid backward flow, the characterized in that of bearing be formed with respectively on the shaft hole pore wall of bearing along axially extended fluid supply tank, second fluid backward flow groove and along the fluid reservoir tank of circumference extension, wherein, the fluid supply tank with positive pressure district intercommunication, second fluid backward flow groove with negative pressure district intercommunication, and, the fluid supply tank is blind groove form, the one end of second fluid backward flow groove with the fluid reservoir tank intercommunication.

In an embodiment of the present invention, the fluid supply groove and the second fluid return groove are disposed in a negative pressure region in the shaft hole, in which a lubricating film is formed when the fluid pump operates.

In an embodiment of the present invention, the fluid supply groove and the second fluid return groove are respectively disposed on two sides of a main load (F) applied to the fluid pump during operation.

In an embodiment of the present invention, when the fluid pump operates, the shaft of the fluid pump is driven to rotate in the shaft hole, in the rotation direction of the shaft, the second fluid return channel is located in the region D on one side of the positive pressure region away from the lubricating film, the fluid supply channel is located in the region E on one side of the positive pressure region entering the lubricating film, and an included angle (α) from the second fluid return channel to the fluid supply channel is greater than or equal to 30 ° and less than or equal to 180 °.

In an embodiment of the present invention, the fluid supply groove is disposed near a position where a thickness of the lubricating film is maximum.

In an embodiment of the present invention, 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 in the axial direction.

In an embodiment of the present invention, the flow path area of the fluid supply tank is larger than the flow path area of the second fluid return tank.

As described above, in the bearing for a fluid pump of the present invention, the fluid supply groove and the fluid return groove extending in the axial direction are formed on the hole wall of the shaft hole, respectively, the fluid supply groove communicates with the positive pressure region, the fluid return groove communicates with the negative pressure region, and the fluid supply groove is a blind groove. The structure enables fluid from the positive pressure area to be pumped into the shaft hole from the fluid supply groove to lubricate the shaft and the shaft hole, and enables the fluid flowing to the outside of the pump body to be sucked back to the negative pressure area through the fluid backflow groove, so that the purpose of lubricating the sliding bearing is achieved, the leakage amount of the fluid to the outside of the pump body is reduced, impurities, oil sludge, friction chips and the like can be taken away with lubricating oil through the fluid backflow groove, and the fluid backflow groove is prevented from being accumulated at the shaft hole to cause abrasion to various moving parts.

Meanwhile, the leakage amount of fluid to the outside of the pump body is reduced, so that the pressure accumulation of the fluid at the oil seal can be reduced, the holding force required by the oil seal for realizing sealing can be reduced, the friction torque when the fluid pump rotates is reduced, the effect of improving the starting success rate of the fluid pump is achieved, the reliability of a product is improved, and meanwhile, the abrasion of the lip part of the oil seal and a rotating shaft is reduced.

As mentioned above, because the pressure of the fluid to be blocked is reduced, the holding force of the oil seal can be reduced, so that the oil seal can be selected from low-grade oil seals, the lower the grade of the oil seal is, the lower the price is, the low-grade oil seal is selected to reduce the overall manufacturing cost of the fluid pump, meanwhile, the rotating shaft and the oil seal of the pump can use cheap raw materials, the cost of the raw materials is reduced, and the cost is reduced more obviously particularly when the fluid pump is produced in a large scale.

According to another technical scheme of the utility model, set up along axially extended fluid supply tank and fluid backward flow groove and along the fluid storage tank of circumference extension on the pore wall in the shaft hole, and the fluid supply tank is the blind groove, one end and the fluid storage tank intercommunication of fluid backward flow groove, pump the fluid that comes from the positive pressure district into the shaft hole from the fluid supply tank and lubricate shaft hole in, make the fluid that flows to the pump body outside store in the fluid storage tank and suck back to the negative pressure district through the fluid backward flow groove again, both reach the purpose of lubricating counter shaft and shaft hole, can prevent effectively that the fluid from leaking to the pump body outside again, consequently can save the oil blanket part, and then can save the pressure equipment technology of oil blanket, the manufacturing cost of the whole pump is lower, simultaneously because there is not the oil blanket, the pivot of fluid pump no longer receives the friction of oil blanket lip, the friction moment when having reduced the pump operation, the pump has lower operation energy consumption, can also reduce the axial height of the bearing in the pump body, and realizes the integral miniaturization of products. The fluid storage tank is arranged to collect the fluid flowing out in the axial direction at the position and to lose pressure, and to temporarily store and collect impurities such as oil sludge and friction debris, and to take away the impurities together with the lubricating oil through the fluid return tank, thereby preventing the impurities from accumulating at the shaft hole and causing abrasion to each moving member.

According to the utility model discloses a fluid pump during operation is located to another technical scheme, and fluid supply tank and fluid reflux groove form the negative pressure region of lubricated film in the shaft hole, are favorable to forming stable lubricated film between axle and shaft hole.

According to the utility model discloses a further technical scheme, the both sides of the main load that receives when fluid pump during operation are located respectively to fluid supply tank and fluid reflux groove, further are favorable to forming stable lubricated membrane between axle and shaft hole.

According to the utility model discloses a further technical scheme, the fluid return tank is located the region of leaving the regional one side of the malleation of lubricated film, and the fluid supply groove is located the region of getting into the regional one side of malleation of lubricated film to the contained angle of the fluid supply groove from the fluid return tank to is more than or equal to 30 and be less than or equal to 180, is favorable to forming stable lubricated film between axle and shaft hole more.

According to another aspect of the present invention, the fluid supply groove is located at an optimum position for forming a stable lubricating film between the shaft and the shaft hole when the film thickness of the lubricating film is near the maximum thickness.

According to another aspect 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 prevent the fluid leakage effectively. According to the utility model discloses a further technical scheme, the flow area of fluid supply tank is greater than the flow area of fluid reflux groove, is favorable to forming the stable lubricated membrane that has good holding power.

Drawings

Fig. 1 is an exploded view of an electric oil pump according to an embodiment of the present invention.

Fig. 2 is a front view of the pump body according to the first embodiment of the present invention.

Fig. 3 shows a cross-sectional view a-a of fig. 2.

Figure 4 shows the operating principle of a gerotor pump.

Fig. 5 is a cross-sectional view of a pump body according to a second embodiment of the present invention.

Fig. 6 is a schematic view showing dynamic pressure lubrication in the shaft hole of the bearing according to the present invention.

Detailed Description

The following description is provided for illustrative purposes, and other advantages and features of the present invention will become apparent to those skilled in the art from the following detailed description.

It should be understood that the structure, ratio, size and the like shown in the drawings attached to the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by those skilled in the art, and are not used for limiting the limit conditions that the present invention can be implemented, so that the present invention has no technical essential meaning, and any structure modification, ratio relationship change or size adjustment should still fall within the scope that the technical content disclosed in the present invention can cover without affecting the function that the present invention can produce and the purpose that the present invention can achieve. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description, and are not intended to limit the scope of the present invention, and changes or adjustments of the relative relationship thereof may be made without substantial technical changes, and the present invention is also regarded as the scope of the present invention.

Referring to fig. 1, an electric oil pump 100 is taken as an example of the fluid pump in the present embodiment, and fig. 1 shows an exploded view of the electric oil pump 100 according to the present invention.

As shown in fig. 1, the electric oil pump 100 is sequentially 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 through fasteners, and the fasteners can be screws, bolts, or pin shafts. The bottom of the base 1 is connected to an application object such as a transmission or an engine (not shown in fig. 1), and the base 1 is provided with an oil inlet 11 and an oil outlet 12 penetrating through the upper and lower end surfaces of the base, so that when the electric oil pump 100 works, the electric oil pump 100 starts the motor 3 to suck oil in the transmission from the oil inlet 11, pressurizes the oil and then pumps the oil out of the oil outlet 12.

The first embodiment of the present invention is shown in fig. 2 and 3, fig. 2 shows a front view of the pump body in the first embodiment, fig. 3 shows a sectional view a-a of fig. 2, and the sectional view is not hatched for the convenience of view. In the present embodiment, as shown in fig. 2 to 3, the pump body 2 includes a pump body 24 and a bearing 25, a chamber 23 is provided in the pump body 24, an outer rotor 21 and an inner rotor 22 that engages with the outer rotor 21 are fitted in the chamber 23, and in fig. 2, a positive pressure region 28 and a negative pressure region 27 are provided on an axial end face 231 of the chamber 23.

It should be noted that the electric oil pump 100 in fig. 1 is a trochoid pump, the operation principle of the trochoid pump is as shown in fig. 4, the inner rotor 22 and the outer rotor 21 are in inner meshing, the inner rotor 22 has 6 outer teeth, correspondingly, the outer rotor 21 has 7 inner teeth, the inner rotor 22 rotates clockwise according to the direction shown in the figure, each outer tooth of the inner rotor 22 is meshed with a different part of the inner tooth of the outer rotor 21, 7 inter-tooth spaces formed between the inner rotor 22 and the outer rotor 21, in fig. 4, the volume of each inter-tooth space formed by the teeth 224 and 225, the teeth 225 and 226, and the teeth 226 and 221 and the outer rotor 21 respectively decreases from large to small, a pressure oil chamber 281, a pressure oil chamber 282 and a pressure oil chamber 283 are formed on the left side of the inner rotor 22, and the pressure oil chamber 281, the pressure oil chamber 282 and the pressure oil chamber 283 are; three inter-tooth spaces are respectively formed between the teeth 221 and 222, between the teeth 222 and 223, and between the teeth 223 and 224 and the outer rotor 21, the volume of each inter-tooth space is changed from small to large, the right side of the inner rotor 22 forms an oil suction cavity 271, an oil suction cavity 272 and an oil suction cavity 273, and the oil suction cavity 272 and the oil suction cavity 273 are respectively communicated with the negative pressure region 27 on the pump body 2. The negative pressure region 27 is communicated with the oil suction cavity 271, the oil suction cavity 272 and the oil suction cavity 273, and the positive pressure region 28 is communicated with the oil pressing cavity 281, the oil pressing cavity 282 and the oil pressing cavity 283. As the inner rotor 22 rotates in the direction shown in the drawing, the oil in the oil suction chamber 273, the oil suction chamber 272 and the oil suction chamber 271 is sent from the negative pressure region 27 to the positive pressure region 28 in this order.

Further, as shown in fig. 3, the bearing 25 has a shaft hole 26, one side of the shaft hole 26 is opened to communicate with the chamber 23, a motor shaft 33 is inserted into the shaft hole 26 to be coupled to the inner rotor 22, the motor shaft 33 is coupled to the motor rotor 32, the motor shaft 33 rotates the inner rotor 22 when the motor 3 is started, 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 the oil seal 5 is opened at an end of the bearing 25 remote from the chamber 23, and a bottom of the groove 29 communicates with the shaft hole 26. In order to ensure the lubrication between the motor shaft 33 and the hole wall of the shaft hole 26, in the present embodiment, a fluid supply groove 253 extending in the axial direction is provided on the hole wall of the shaft hole 26, the fluid supply groove 253 is in a blind groove shape, and the opening end thereof is communicated with the chamber 23; a first fluid-return groove 254 extending in the axial direction is further provided on the hole wall of the shaft hole 26, the first fluid-return groove 254 communicating with the chamber 23 and penetrating the hole wall of the shaft hole 26, specifically, according to fig. 3, the first fluid-return groove 254 communicating with the groove 29 for placing the oil seal 5. A fluid supply passage 251 and a fluid return passage 252 are provided in the axial end surface 231 of the chamber 23, the fluid supply passage 251 communicating with the positive pressure region 28 and the fluid supply groove 253, and the fluid return passage 252 communicating with the negative pressure region 27 and the first fluid return groove 254.

The positive pressure region 28 communicates with the fluid supply groove 253 through the fluid supply passage 251, supplies oil to the shaft hole 26, and lubricates the motor rotating shaft 33 and the shaft hole 26; the negative pressure region 27 communicates with the first fluid return groove 254 through the fluid return flow path 252, and draws oil from the shaft hole 26, thereby preventing the lubricating oil from flowing out to the outside of the pump body 2 along the motor rotation shaft 33.

It should be noted that when the oil in the positive pressure region 28 is pumped into the gap between the motor shaft 33 and the hole wall of the shaft hole 26 along the fluid supply groove 253, because the fluid supply groove 253 is in a blind groove shape, the oil can only flow to the closed end of the fluid supply groove 253, and the closed end of the fluid supply groove 253 plays a role in interception, so that the oil in the fluid supply groove 253 is difficult to flow into the motor 3.

In addition, the provision of the first fluid return groove 254 also functions to clean the sliding bearing, and takes away impurities, sludge, and friction debris together with the lubricating oil, thereby preventing the accumulation thereof in the shaft hole 26 from causing wear to the moving parts, which may cause a failure of the electric oil pump 100.

Further, in the present embodiment, the bottom of the groove 29 for placing the oil seal 5 communicates with the shaft hole 26, but the groove 29 does not communicate with the fluid supply groove 253. During assembly, the oil seal 5 is sleeved on the motor rotating shaft 33, and certain holding force exists between the oil seal 5 and the motor rotating shaft 33. It should be noted that, since the fluid supply groove 253 is not directly communicated with the groove 29 where the oil seal 5 is located, and at the same time, both the oil in the shaft hole 26 and the oil collected in the groove 29 are sucked back to the negative pressure region 27 by the first fluid return groove 254, the oil pressure accumulated in the oil seal 5 is reduced, and since the oil pressure to be blocked is reduced, the holding force of the oil seal 5 can be reduced, thereby achieving the effects of reducing the friction torque when the electric oil pump 100 rotates and improving the starting success rate of the electric oil pump 100, and further, the energy consumption during operation can be reduced, the efficiency of the electric oil pump 100 can be improved, and since the abrasion between the lip portion of the oil seal and the rotating shaft is reduced, the reliability of the product can be improved.

Because the oil pressure needing to be blocked is reduced, the holding force of the oil seal 5 can be reduced, so that the oil seal 5 can be selected from low-grade oil seals, the lower the grade of the oil seal 5 is, the lower the price is, the low-grade oil seal 5 can be selected to reduce the overall manufacturing cost of the electric oil pump 100, meanwhile, the motor rotating shaft 33 and the oil seal 5 can be made of cheap raw materials, the raw material cost is reduced, and particularly when the electric oil pump is produced in a large scale, the cost reduction is more obvious.

Figure 5 shows a section through a second embodiment of the pump body, which section is not hatched for ease of illustration. As shown in fig. 5, the present embodiment is different from the first embodiment in that: 1. instead of the groove 29 for the oil seal 5, a fluid reservoir 255 extending in the circumferential direction is provided on the hole wall of the shaft hole 26; 2. the second fluid-return groove 254' provided in the axial direction on the hole wall of the shaft hole 26 has one end communicating with the chamber 23 and the other end communicating with the fluid reservoir groove 255.

The fluid reservoir 255 is provided to collect and decompress oil flowing in the axial direction of the motor shaft 33, and to temporarily store impurities such as sludge and friction debris therein, thereby preventing damage to the moving parts.

The positive pressure region 28 communicates with the fluid supply groove 253 through the fluid supply passage 251, supplies oil to the shaft hole 26, and lubricates the motor rotating shaft 33 and the shaft hole 26; the negative pressure region 27 communicates with the second fluid return groove 254 'through the fluid return flow path 252, and the lubricating oil collected in the hole wall of the shaft hole 26 and the fluid reservoir groove 255 is drawn back into the negative pressure region 27 through the second fluid return groove 254', thereby blocking leakage of the oil flowing in the axial direction to the outside of the pump body 2. On the other hand, impurities such as sludge and friction debris temporarily stored in the fluid reservoir tank 255 can be drawn back to the negative pressure region 27 through the second fluid-returning groove 254', and the cleaning of the sliding bearing oil passage is ensured.

In this embodiment, after the fluid storage tank 255 is provided, the situation that oil flows out of the pump body 2 no longer occurs, and at this time, parts of the oil seal 5 can be omitted, so that the press-fitting process of the oil seal 5 and the oil seal 5 can be omitted, the manufacturing cost of the whole electric oil pump 100 is lower, and meanwhile, because there is no oil seal 5, the motor rotating shaft 33 no longer receives friction of the lip of the oil seal, the friction torque when the rotating shaft of the electric oil pump 100 rotates is reduced, and the lower operation energy consumption is achieved, and in addition, the axial height of the pump body 2 can be reduced, and the effect of integrally miniaturizing the product.

In the first and second embodiments, the fluid supply flow path 251 communicates the fluid supply groove 253 with the positive pressure region 28; the fluid return flow path 252 communicates the first fluid return groove 254 or the second fluid return groove 254' with the negative pressure region 27. During the operation of the electric oil pump 100, the motor shaft 33 is affected by the main load, and 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. The main load may be a rotating part of the electric oil pump 100, such as gravity of the inner rotor 22, the motor rotating shaft 33, the motor rotor, magnetic steel, and the like, a radial thrust of the oil pressure received by the inner rotor 22, and the like.

As shown in fig. 6, the motor shaft 33 rotates as shown in the drawing while the motor shaft 33 is subjected to a main load F in the direction shown in the drawing, and fig. 6 shows a lubricating oil film formed by the rotation of the motor shaft 33 in the shaft hole. Referring to fig. 6, according to the hydrodynamic lubrication principle, the hatched portion is a bearing region of a lubricating oil film, the bearing region is a positive pressure region of the oil film, and the rest of the bearing region except the positive pressure region is an oil film negative pressure region.

To ensure that oil in the positive pressure region 28 can be continuously pumped into the shaft bore 26, further, the fluid supply groove 253, the first fluid return groove 254, or the second fluid return groove 254' is provided in a negative pressure region in the shaft bore 26 that forms a lubrication film when the pump body 2 is in operation. In the present embodiment, the fluid supply flow path 251 and the fluid return flow path 252 are respectively provided on both sides of the main load F applied to the pump body 2 during operation, and fig. 6 shows that the areas where the fluid supply groove 253, the first fluid return groove 254, or the second fluid return groove 254 'are provided are an area E and an area D, respectively, that is, the fluid supply groove 253 is provided in the area E on the side of the positive pressure area entering the lubricating film, and the first fluid return groove 254 or the second fluid return groove 254' is provided in the area D on the side of the positive pressure area leaving the lubricating film.

Preferably, angle α from first fluid-return groove 254, second fluid-return groove 254 ' to fluid-feed groove 253 is greater than or equal to 30 ° and less than or equal to 180 °, if angle α is less than 30 °, it may happen that oil is drawn directly from first fluid-return groove 254 or second fluid-return groove 254 ' from fluid-feed groove 253 into shaft bore 26, which is detrimental to the formation of the lubricating film, if angle α is greater than 180 °, fluid-feed groove 253 and/or first fluid-return groove 254 or second fluid-return groove 254 ' will approach the positive pressure region of the lubricating film, disrupting the formation of the positive pressure region of the lubricating film.

Further, it is preferable that the fluid supply groove 253 is provided in the vicinity of the position where the film thickness of the lubricating film is maximum, that is, in the vicinity of the position where the gap between the shaft and the shaft hole is maximum, in this case, both the lubrication and the leakage prevention can be achieved with good effect.

Further, if the axial length of the fluid supply groove 253 is too short, a part of the shaft may not be sufficiently lubricated, and if the axial length is too long, leakage of the oil liquid in the axial direction may be easily increased, which is not only disadvantageous to lubrication of the shaft but also reduces the efficiency of the entire oil pump. In the present invention, the ratio of the axial length of the fluid supply groove 253 to the axial hole 26 degree length 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.

Further, in order to form a stable lubricating film having a good supporting function in the shaft hole 26, the flow passage area of the fluid supply groove 253 should be made larger than the flow passage area of the first fluid return groove 254 or the second fluid return groove 254'.

Next, the operation of the present invention configured as described above will be described.

Assuming that the motor shaft 33 is subjected to the main load F as shown in fig. 6, the motor shaft 33 of the motor 3 drives the inner rotor 22 to rotate, and the inner rotor 22 drives the outer rotor 21 to rotate, whereby the oil is sucked into the negative pressure region 27 from the oil inlet hole 11, and then pumped into the positive pressure region 28 and then pumped out from the oil outlet hole 12. In this process, due to the presence of positive pressure in the positive pressure region 28, the oil in the positive pressure region 28 is pumped into the fluid supply groove 253 through the fluid supply flow path 251, and the oil in the fluid supply groove 253 is brought into the gap between the motor rotating shaft 33 and the shaft hole 26 of the pump body 2 during the rotation of the motor rotating shaft 33, wraps the outer circumferential surface of the motor rotating shaft 33, and flows back into the negative pressure region 27 from the first fluid return groove 254 or the second fluid return groove 254'.

For the first embodiment, during the rotation of the motor shaft 33, there is a small amount of lubricant flowing to the oil seal 5 along the motor shaft 33, and the small amount of lubricant is blocked due to the presence of the oil seal 5, and meanwhile, since the first fluid return groove 254 is communicated with the groove 29, the oil at the oil seal 5 is sucked back into the first fluid return groove 254, and it is ensured that there is no oil pressure flowing out of the oil seal 5 to the outside of the pump body 2.

With respect to the second embodiment, in the rotation process of the motor rotation shaft 33, the lubricating oil flowing to the outside of the pump body 2 along the motor rotation shaft 33 is collected in the fluid storage groove 255 and loses pressure, and is sucked back into the negative pressure region 27 through the second fluid return groove 254', so that the press-fitting process of the oil seal 5 and the oil seal 5 can be omitted, the overall manufacturing cost of the electric oil pump 100 can be greatly reduced, the thickness of the electric oil pump 100 can be shortened in the axial direction corresponding to the arrangement of the oil seal, and the miniaturization of the product can be realized.

Although the electric oil pump 100 is described above as an example, it should be understood by those skilled in the art that the present invention is not limited to the electric oil pump 100, and may be any fluid pump such as a water pump and an air pump. In addition, although the present invention has been described by taking a gerotor pump as an example, it should be understood by those skilled in the art that the present invention is not limited to the gerotor pump, and may be any pump such as a vane pump, a plunger pump, and other gear pumps, as long as a positive pressure region for pumping out the fluid and a negative pressure region for flowing in the fluid are formed in the fluid pump when the fluid pump is operated. The bearing may be separate from the pump body and may be fixed to the pump body by attachment.

To sum up, the utility model discloses various shortcomings in the prior art have effectively been overcome and high industry value has.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (14)

1. A bearing for a fluid pump in which a positive pressure region (28) for pumping out a fluid and a negative pressure region (27) for flowing in the fluid are formed when the fluid pump is operated,

the bearing (25) is characterized in that a fluid supply groove (253) and a first fluid return groove (254) which extend along the axial direction are respectively formed on the hole wall of the shaft hole (26) of the bearing (25), wherein the fluid supply groove (253) is communicated with the positive pressure zone (28), the first fluid return groove (254) is communicated with the negative pressure zone (27), and the fluid supply groove (253) is in a blind groove shape.

2. The bearing for a fluid pump as claimed in claim 1, wherein the fluid supply groove (253) and the first fluid-return groove (254) are provided in a negative pressure region in which a lubrication film is formed in the shaft hole (26) when the fluid pump is operated.

3. A bearing for a fluid pump according to claim 2, wherein the fluid supply groove (253) and the first fluid-return groove (254) are provided on both sides of a main load (F) to which the fluid pump is subjected when operating, respectively.

4. A bearing for a fluid pump as claimed in claim 3, wherein when said fluid pump is operated, a shaft driving the fluid pump rotates in said shaft hole (26), said first fluid-return groove (254) is located in a region D on a side of a positive pressure region away from the lubricating film, said fluid-supply groove (253) is located in a region E on a side of a positive pressure region into the lubricating film, and an angle (α) from said first fluid-return groove (254) to said fluid-supply groove (253) is greater than or equal to 30 ° and less than or equal to 180 °.

5. The bearing for a fluid pump according to claim 4, wherein the fluid supply groove (253) is provided in the vicinity of a position where a film thickness of the lubrication film is maximum.

6. The bearing for a fluid pump according to any one of claims 1 to 5, wherein a ratio of a length of the fluid supply groove (253) to a length of the shaft hole (26) in the axial direction is greater than or equal to 0.5 and less than or equal to 0.95.

7. A bearing for a fluid pump according to any one of claims 1 to 5, wherein the fluid supply groove (253) has a larger flow area than the first fluid return groove (254).

8. A bearing for a fluid pump in which a positive pressure region (28) for pumping out a fluid and a negative pressure region (27) for returning the fluid are formed when the fluid pump is operated, the bearing (25) being characterized in that a fluid supply groove (253) extending in an axial direction, a second fluid return groove (254 ') and a fluid reservoir groove (255) extending in a circumferential direction are formed in a hole wall of a shaft hole (26) of the bearing (25), respectively, wherein the fluid supply groove (253) communicates with the positive pressure region (28), the second fluid return groove (254 ') communicates with the negative pressure region (27), and the fluid supply groove (253) has a blind groove shape, and one end of the second fluid return groove (254 ') communicates with the fluid reservoir groove (255).

9. The bearing for a fluid pump according to claim 8, wherein the fluid supply groove (253) and the second fluid-return groove (254') are provided in a negative pressure region in which a lubrication film is formed in the shaft hole (26) when the fluid pump is operated.

10. A bearing for a fluid pump according to claim 9, wherein the fluid supply groove (253) and the second fluid-return groove (254') are provided on both sides of a main load (F) to which the fluid pump is subjected when operating, respectively.

11. The bearing for a fluid pump as claimed in claim 10, wherein when the fluid pump is operated, a shaft that drives the fluid pump rotates in the shaft hole (26), the second fluid-return groove (254 ') is located in a region D on the side of the positive pressure region away from the lubricating film, the fluid-supply groove (253) is located in a region E on the side of the positive pressure region into the lubricating film, and an angle (α) from the second fluid-return groove (254') to the fluid-supply groove (253) is greater than or equal to 30 ° and less than or equal to 180 °.

12. The bearing for a fluid pump according to claim 11, wherein the fluid supply groove (253) is provided in the vicinity of a position where a film thickness of the lubrication film is maximum.

13. The bearing for a fluid pump according to any one of claims 8 to 12, wherein a ratio of a length of the fluid supply groove (253) to a length of the shaft hole (26) in the axial direction is greater than or equal to 0.5 and less than or equal to 0.95.

14. A bearing for fluid pump according to any one of claims 8 to 12, wherein the fluid supply groove (253) has a larger flow area than the second fluid return groove (254').

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