CN210919828U

CN210919828U - Bearing for fluid pump

Info

Publication number: CN210919828U
Application number: CN201921138576.9U
Authority: CN
Inventors: 杨鲁川
Original assignee: Changzhou Rich Engine Technology Co ltd
Current assignee: Changzhou Rich Engine Technology Co ltd
Priority date: 2019-07-18
Filing date: 2019-07-18
Publication date: 2020-07-03
Anticipated expiration: 2029-07-18

Abstract

The utility model provides a bearing for fluid pump, work as fluid pump during operation be formed with positive pressure district (28) that supply the 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 lubrication groove (261) on shaft hole (26) pore wall of bearing (25), lubrication groove (261) with positive pressure district (28) intercommunication, and this lubrication groove (261) are blind groove form. The utility model discloses can reduce the power of holding tightly of oil blanket, reduce the manufacturing cost of fluid 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-mentioned technical solution implements lubrication of the sliding bearing with a relatively simple structure and relatively low cost, in order to prevent the lubricating oil from flowing out to the outside of the pump along the motor shaft, a sealing member needs to be disposed between the pump housing and the motor shaft, and in order to ensure good sealing performance, a certain holding force is required between the motor shaft and the sealing member, which increases the starting torque of the oil pump, causes an increase in the failed starting rate, increases the loss of the oil pump, and reduces the efficiency; 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 shortcomings of the prior art, an object of the present invention is to provide a bearing for fluid pump, which can not only realize good lubrication, but also prevent excessive oil from flowing to the oil seal, thereby reducing the holding force of the oil seal and finally reducing the friction torque.

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 lubricating groove extending along the axial direction is formed on the hole wall of the shaft hole of the bearing, the lubricating groove is communicated with the positive pressure area, and the lubricating groove is in a blind groove shape.

In an embodiment of the present invention, the lubrication groove is located in the negative pressure region of the shaft hole where the lubrication film is formed when the fluid pump works.

In an embodiment of the present invention, in the axial direction, a ratio of the length of the lubrication groove to the length of the shaft hole is greater than or equal to 0.5 and less than or equal to 0.95.

In an embodiment of the present invention, the lubrication grooves are respectively disposed on two sides of the main load applied to the fluid pump during operation.

In an embodiment of the present invention, when the fluid pump works, the shaft of the driving fluid pump rotates in the shaft hole, in the rotation direction of the shaft, one of the lubrication grooves is located in the area on one side of the positive pressure region where the lubrication film is separated, and the other lubrication groove is located in the area on one side of the positive pressure region where the lubrication film enters.

In an embodiment of the present invention, an included angle between the two lubricating grooves is greater than or equal to 30 ° and less than or equal to 180 °.

In an embodiment of the present invention, the lubrication groove is disposed at a position where a thickness of the film of the lubrication film is maximum.

As above, the utility model discloses a bearing reduces the overstock of oil blanket department oil, can reduce the power of hugging tightly of oil blanket to reached the friction torque moment of torsion when reducing the fluid pump rotation, improved the effect of fluid pump start-up success rate, consequently improved the reliability of product, simultaneously, reduced the wearing and tearing of oil blanket lip and pivot.

The oil pressure of the plugging is reduced, the oil seal holding force can be reduced, so that the oil seal can be selected from a low-grade oil seal, the lower the grade of the oil seal is, the lower the price is, the low-grade oil seal is selected, the overall manufacturing cost of the fluid pump can be reduced, meanwhile, the motor rotating shaft and the oil seal can be made of cheap raw materials, the cost of the raw materials is reduced, and particularly when the motor rotating shaft and the oil seal are generated in a large batch, the cost is reduced.

Drawings

Fig. 1 is an exploded view of a fluid pump according to an embodiment of the present invention.

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

FIG. 3 shows a cross-sectional view A-A of the pump body of FIG. 2.

Figure 4 shows the operating principle of a gerotor pump.

Fig. 5 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.

Fig. 1 is an exploded view of an electric oil pump 100. 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 with an application object such as a gearbox or an engine (not shown in fig. 1), and the base 1 is provided with an oil inlet hole 11 and an oil outlet hole 12 which penetrate through the upper and lower end surfaces of the base.

Fig. 2 shows a front view of the pump body in an embodiment, and fig. 3 shows a cross-section a-a of fig. 2, the cross-section being sectioned for ease of illustration.

As shown in fig. 3, the bearing 25 is integrally formed on a pump body 2, the pump body 2 further has a pump body 24, a chamber 23 is formed on one axial wall surface of the pump body 24, an outer rotor 21 and an inner rotor 22 engaged with the outer rotor 21 are fitted in the chamber 23, a gerotor pump is formed, a positive pressure region 28 for pumping out fluid and a negative pressure region 27 for flowing in fluid are formed when the electric oil pump 100 is operated, in the embodiment, the positive pressure region 28 and the negative pressure region 27 are formed on an axial end surface 231 of the chamber 23, and the inner rotor 22 and the outer rotor 21 are rotated in the chamber 23 to suck and pump oil. Through holes 20 for fixing the pump body are formed in the circumferential direction of the pump body 24, and the pump body 2 is connected with the base 1 and the motor 3 through fasteners.

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.

As shown in fig. 2-3, the bearing 25 has a shaft hole 26 penetrating through itself, one side of the shaft hole 26 communicates with the chamber 23, a motor shaft 33 is inserted into the shaft hole 26 and connected with the inner rotor 22, the motor rotor 32 is sleeved outside the motor shaft 33, the motor shaft 33 drives the inner rotor 22 to rotate when the motor 3 is started, and the bearing 25 of the pump body 2 constitutes a sliding bearing of the motor shaft 33.

In order to lubricate the gap between the motor shaft 33 and the hole wall of the shaft hole 26, a lubrication groove 261 is provided along the axial direction of the hole wall of the shaft hole 26, the lubrication groove 261 is blind, the lubrication groove 261 is communicated with the positive pressure region 28 through an oil supply passage 263, and the oil supply passage 263 is provided on the axial end face of the cavity 23. Fig. 2 shows a pair of lubrication grooves 261 symmetrically arranged in the circumferential direction, but this does not mean that the lubrication grooves 261 must be arranged in 2, the number of lubrication grooves 261 may be arbitrary, and the shape and the positional relationship of the lubrication grooves 261 are not particularly limited. The lubrication groove 261 may be formed integrally with the pump body 2 or may be formed by cutting. The negative pressure region 27 is communicated with the oil suction cavity 271, the oil suction cavity 272 and the oil suction cavity 273, the positive pressure region 28 is communicated with the oil pressing cavity 281, the oil pressing cavity 282 and the oil pressing cavity 283, and the oil pressure of the positive pressure region 28 is obviously greater than that of the negative pressure region 27.

It should be noted that the position of the lubrication groove 261 shown in fig. 2 may be set according to the direction of the main load applied to the motor rotating shaft 33, wherein the main load may be the rotating part of the electric oil pump 100, such as the inner rotor 22, the motor rotating shaft 33, the gravity of the motor rotor and the magnetic steel, and the like, the radial thrust of the oil pressure applied to the inner rotor 22, and the like. When the position of the lubrication groove 261 is set, first, the main load direction of the electric oil pump 100 and the positive pressure region and the negative pressure region in the shaft hole 26 where the lubricating oil film is formed are determined. In the present embodiment, the general direction of the main load in fig. 2 is directed to the negative pressure region 27 along the positive pressure region 28, as shown in fig. 5, a schematic view of dynamic pressure lubrication in the shaft hole 26 after the main load is applied to the motor shaft 33 is given, the main load in fig. 5 is a main load F, the motor shaft 33 rotates in the illustrated manner, referring to fig. 5, according to the fluid dynamic pressure lubrication principle, a hatched portion in fig. 5 is a bearing region of a lubricating oil film, the bearing region is a positive pressure oil film region, and the rest of the bearing region is a negative pressure oil film region.

In order to ensure the stability of the oil film in the shaft hole 26, fig. 5 shows a region E and a region D where the lubrication grooves can be disposed, and in this embodiment, a plurality of lubrication grooves 261, preferably disposed near the position where the film thickness of the lubrication film is maximum, i.e., the position where the gap between the shaft and the shaft hole is maximum, can be opened along the axial direction of the shaft hole 26. The position of the lubrication groove 261 in the circumferential direction can be designed and adjusted according to the oil pressure of the lubricating oil in the positive pressure region 28.

In addition, the axial length of the lubrication groove 261 is too short, so that a part of the shaft can not be sufficiently lubricated, and the leakage of the oil liquid along the axial direction is easily aggravated if the axial length is too long, so that the lubrication of the shaft is not facilitated, and the overall efficiency of the oil pump is reduced. In the axial direction, the ratio of the length of the lubrication groove 261 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.

Referring to fig. 2 and 5, the two sides of the main load F on the electric oil pump 100 are respectively provided with a lubrication groove 261, when the fluid pump works, the motor shaft 33 driving the electric oil pump 100 rotates in the shaft hole, in the rotation direction of the shaft, one of the lubrication grooves 261 is located in the area D away from the positive pressure area side of the lubrication film, and the other lubrication groove 261 is located in the area e entering the positive pressure area side of the lubrication film, wherein the included angle α between the two lubrication grooves 261 is greater than or equal to 30 ° and less than or equal to 180 °, so as to ensure that a complete lubrication film can be formed in the shaft hole 26.

In addition, in this embodiment, when the number of the lubricating grooves 261 is more than 2, an oil accumulating groove 262 is further formed on the axial end surface of the chamber, the oil accumulating groove 262 communicates all the lubricating grooves 261, and the oil accumulating groove 262 communicates with the oil supply passage 263, the oil accumulating groove 262 is provided to accumulate the oil from the positive pressure region 28 in the oil accumulating groove 262, and can stably supply the oil to each lubricating groove, and the oil accumulating groove 262 may be formed around the shaft hole 26, may be annular, semi-annular, or other shapes, and is not limited herein.

In fig. 3, the motor shaft 33 rotates in the shaft hole 26, a gap exists between the motor shaft 33 and the hole wall of the shaft hole 26, the inner rotor 22 and the outer rotor 21 suck oil into the negative pressure region 27 through the oil inlet 11, the oil is pumped into the positive pressure region 28 in the rotation process of the inner rotor 22 and the outer rotor 21, and simultaneously enters between the motor shaft 33 and the hole wall of the shaft hole 26 through the lubricating groove 261, an oil film is generated along with the rotation of the motor shaft 33, the motor shaft 33 is wrapped, and the motor shaft 33 is lubricated and radially supported.

In addition, since the lubrication groove 261 has a blind groove shape (as shown in fig. 3), the closed end thereof intercepts the oil flowing into the lubrication groove 261, which allows only a very small amount of oil to flow beyond the closed end to the oil seal 5 although the outflow of the oil cannot be completely prevented, which greatly reduces the pressure of the oil against the oil seal 5 as a sealing member. In addition, compare in the lubrication groove that the axial link up completely the utility model discloses the most part oil all is intercepted by the blind end of lubrication groove 261, so to carry out lubricated oil between motor shaft 33 and shaft hole 26 and just reduced, consequently, the oil pump loss can reduce, and efficiency can improve.

In the present embodiment, a groove 29 (shown in fig. 3) for placing the oil seal 5 is opened at the end of the bearing 25 away from the positive pressure region 28 and the negative pressure region 27, the groove 29 communicates with the shaft hole 26, and the groove 29 does not communicate with the lubrication groove 261. 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, because the lubrication groove 261 is not directly communicated with the groove 29 where the oil seal 5 is located, and meanwhile, because the lubrication groove 261 is in a blind groove shape, the oil seal 5 in this embodiment is not prone to oil overstock, and therefore, because the oil pressure to be blocked is reduced, the holding force of the oil seal 5 can be reduced in the design, the purposes of reducing the friction torque when the electric oil pump 100 rotates and improving the starting success rate of the electric oil pump 100 are achieved, the reliability of the product is improved, and meanwhile, the abrasion of the lip portion and the rotating shaft of the oil seal 5 is reduced. Meanwhile, the holding force of the oil seal 5 is reduced, the material grade of the oil seal 5 can be greatly reduced, the lower the material grade of the oil seal 5 is, the lower the price is, the oil seal 5 made of low-grade material can reduce the overall manufacturing cost of the electric oil pump 100, meanwhile, the motor rotating shaft 33 can also use 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.

It should be noted that, in actual use, the oil entering lubrication groove 261 may be replaced with other liquid or gas, such as water or air.

Next, a pump action of the electric oil pump 100 configured as described above will be described.

The electric oil pump 100 is assembled as shown in fig. 1, and in operation, the motor 3 is first started.

As shown in fig. 1, oil in the transmission is sucked into the base 1 from the oil inlet hole 11 and pumped out from the oil outlet hole 12, and during the rotation of the rotor 2, part of the oil in the oil outlet hole 12 is pumped into the positive pressure region 28 through the volume change between the cycloid rotors, and flows into the lubricating groove 261 according to fig. 2, and the oil in the lubricating groove 261 is brought into the friction surface between the motor rotating shaft 33 and the shaft hole 26 in the pump body 2 during the rotation of the motor rotating shaft 33, and generates an oil film along with the rotation of the motor rotating shaft 33, thereby performing the lubricating and radial supporting functions on the motor rotating shaft 33.

According to the illustration in fig. 3, the oil flowing into the lubricating groove 261 is intercepted at the closed end of the lubricating groove 261 in the axial flowing process along with the motor rotating shaft 33, so that the amount of oil which can flow to the oil seal is very small, the oil pressure borne by the oil seal can be reduced, the oil flowing to the oil seal 5 can be limited to the greatest extent, the holding force and the material grade of the oil seal 5 are greatly reduced, and therefore the motor rotating shaft 33 and the oil seal 5 can use cheap raw materials, the raw material cost is reduced, and the manufacturing cost of the electric oil pump 100 is reduced.

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

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 inflow of the fluid are formed when the fluid pump is operated, characterized in that,

and a lubricating groove (261) extending along the axial direction is formed on the hole wall of the shaft hole (26) of the bearing (25), the lubricating groove (261) is communicated with the positive pressure area (28), and the lubricating groove (261) is in a blind groove shape.

2. The bearing for a fluid pump as claimed in claim 1, wherein the lubrication groove (261) is provided in a negative pressure region where a lubrication film is formed in the shaft hole (26) when the fluid pump is operated.

3. Bearing for a fluid pump according to claim 1, characterized in that the ratio of the length of the lubrication groove (261) to the 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.

4. Bearing for a fluid pump according to claim 2, characterized in that one lubrication groove (261) is provided on each side of the main load (F) to which the fluid pump is subjected during operation.

5. The bearing for a fluid pump as claimed in claim 4, wherein when the fluid pump is operated, a shaft that drives the fluid pump rotates in the shaft hole (26), and in a rotation direction of the shaft, one of the lubrication grooves (261) is located in a region D on a side of a positive pressure region that is away from a lubrication film, and the other lubrication groove (261) is located in a region E on a side of a positive pressure region that is into the lubrication film.

6. Bearing for a fluid pump according to claim 5, characterized in that the angle (α) between the two lubrication grooves (261) is greater than or equal to 30 ° and less than or equal to 180 °.

7. The bearing for a fluid pump according to claim 2, wherein the lubrication groove (261) is provided where a film thickness of the lubrication film is maximum.