Self-lubricating internal gear pump

Abstract

The utility model discloses a self-lubricating internal gear pump which comprises a pump body, an internal gear and a driving wheel are arranged in the pump body, the driving wheel is meshed in the internal gear in an offset mode, a cavity between the internal gear and the driving wheel is divided into an oil suction cavity and an oil pressing cavity through a crescent plate, and the arc face of the inner side of the crescent plate is in clearance fit with the driving wheel. The center line of the arc surface on the inner side of the crescent plate is deviated towards the oil suction cavity relative to the center line of the driving wheel; the center line of the inner wall of the pump body deviates towards the oil suction cavity relative to the center line of the inner gear. According to the self-lubricating internal gear pump in the technical scheme, the arc surface on the inner side of the crescent plate and the inner wall of the pump body are arranged in an offset manner, so that the lubricating performance between the crescent plate and the internal and external gears and between the internal gear and the inner wall of the pump is greatly improved, and the service life of the internal gear pump is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydraulic pump technical field especially is related to a self -lubricating internal gear pump. BACKGROUND

[0002] Internal gear pump has compact structure, small flow pulsation, big pressure, low noise, good self -priming performance, large speed range etc. outstanding advantages, contain a pair of having involute tooth shape's external gear and internal gear mesh each other, external gear is driving wheel, internal gear is driven wheel, the oil suction chamber and the oil pressure chamber are separated with crescent board between two gears, two gear directions are same, the tooth that enters the oil suction chamber exits meshing, thereby make the oil suction chamber volume increase, form vacuum, oil is inhaled under the action of atmospheric pressure, two gears bring the oil liquid of oil suction chamber into the oil pressure chamber, the gear that enters the oil pressure chamber enters meshing, the oil pressure chamber volume reduces, oil is pressed out, completes the oil discharge process.

[0003] For example, Chinese patent publication No. CN113404689A, publication date is September 17, 2021, named "internal gear pump", including pump body, the pump cavity of pump body is equipped with internal gear, internal gear is equipped with driving gear, internal gear is offset relative to driving gear, the outside of the bite side of the meshing place of driving gear and internal gear is equipped with positioning rod, sealing device is equipped between meshing place and positioning rod, sealing device includes crescent main board, crescent sub board, spring piece, sealing rod. Three through holes are arranged on the inner side face arc length of two fifths of crescent main board, the included angle between the axial center line of through hole and the normal line of inner side face is 24.68 °, and it is inclined to positioning rod side, the diameter of through hole is 0.52mm.

[0004] The existing patent has the following shortcomings: the internal gear of the existing internal gear pump and the inner wall of the pump body have large wear, and the contact surface between the inner side arc surface of the crescent plate and the driving wheel has large wear, which reduces the stability and service life of the internal gear pump. UTILITY MODEL CONTENTS

[0005] The utility model discloses a kind of self-lubricating internal gear pumps, including pump body, the pump cavity of pump body is equipped with internal gear, internal gear is equipped with driving gear, internal gear is offset relative to driving gear, the outside of the bite side of the meshing place of driving gear and internal gear is equipped with positioning rod, sealing device is equipped between meshing place and positioning rod, sealing device includes crescent main board, crescent sub board, spring piece, sealing rod.

[0006] To achieve the above object, the utility model adopts the following technical scheme:

[0007] The utility model provides a kind of self-lubricating internal meshing gear pump, including pump body, internal gear and driving wheel that are arranged in pump body, the cavity between internal gear and driving wheel is divided into oil suction cavity and oil pressing cavity by crescent plate, the inside arc surface of the crescent plate is gap cooperation with driving wheel, and the centre line of the inside arc surface of the crescent plate is offset relative to the centre line of driving wheel towards oil suction cavity;The centre line of the inner wall of pump body is offset relative to the centre line of internal gear towards oil suction cavity.The utility model discloses a kind of self-lubricating internal meshing gear pump, by the inside arc surface of the crescent plate and the inner wall of pump body offset setting, greatly improve the lubricating property between crescent plate and internal gear, improve the service life of internal meshing gear pump.

[0008] Due to the combined force of oil hydraulic pressure and gear meshing force on the internal gear, the internal gear generates a large pressure on the inner wall of the pump body towards the oil suction cavity, resulting in a smaller gap between the internal gear and the inner wall of the pump body on the oil suction cavity side than on the oil pressing cavity side, reducing the lubricating property and causing adhesive friction between the internal gear and the inner wall of the pump body, which leads to the internal gear and the pump body being glued together and then causing the internal meshing gear pump to fail. In the technical solution, the centre line of the inner wall of the pump body is offset relative to the centre line of the internal gear towards the oil suction cavity, so that the gap between the internal gear and the inner wall of the pump body on the oil suction cavity side is larger than on the oil pressing cavity side. On the one hand, this generates a dynamic lubrication effect between the internal gear and the inner wall of the pump body, improving the lubricating property between them. On the other hand, this avoids the problem of the internal gear generating a large pressure on the inner wall of the pump body due to the combined force of oil hydraulic pressure and gear meshing force, reducing the wear and gluing between the internal gear and the pump body.

[0009] By offsetting the centre line of the inner wall of the pump body relative to the centre line of the internal gear towards the oil suction cavity, the gap between the outer arc surface of the crescent plate and the internal gear gradually decreases from the oil suction cavity to the oil pressing cavity during the operation of the internal gear ring under high speed and high oil pressure conditions, forming an oil wedge structure with converging gap between the outer arc surface of the crescent plate and the internal gear, increasing the dynamic lubrication effect between them, improving the lubricating property and reducing the wear between the crescent plate and the internal gear.

[0010] Since the contact surface between the inside arc surface of the crescent plate and the driving wheel wears quickly, in the technical solution, the centre line of the inside arc surface of the crescent plate is offset relative to the centre line of the driving wheel towards the oil suction cavity, so that the gap between the inside arc surface of the crescent plate and the driving wheel gradually decreases from the oil suction cavity to the oil pressing cavity, forming an oil wedge structure with converging gap between them, increasing the dynamic lubrication effect between them, improving the lubricating property and reducing the wear between the crescent plate and the driving wheel.

[0011] The center line of the inner side arc surface of the crescent plate is offset relative to the center line of the driving wheel towards the oil suction cavity, and the center line of the inner wall of the pump body is offset relative to the center line of the internal gear towards the oil suction cavity, so that self-lubricating performance is generated between the crescent plate and the driving wheel, between the crescent plate and the internal gear, and between the internal gear and the inner wall of the pump body, wear of the internal gear pump is reduced, and stability and service life of the internal gear pump are improved.

[0012] As preferred, the included angle between the plane formed by the center line of the inner side arc surface of the crescent plate and the center line of the driving wheel and the plane formed by the center line of the inner wall of the pump body and the center line of the internal gear is an acute angle. The lubricating performance is optimized.

[0013] As preferred, the outer side arc surface of the crescent plate is clearance fitted with the internal gear, and the center line of the outer side arc surface of the crescent plate is offset relative to the center line of the driving wheel towards the oil discharge cavity. The similar converging gap oil wedge structure is formed between the crescent plate and the driving wheel and between the crescent plate and the internal gear, self-lubricating performance is generated, wear of the crescent plate and the driving wheel and the internal gear is reduced, and stability and service life of the internal gear pump are improved.

[0014] As preferred, the center line of the inner side arc surface of the crescent plate, the center line of the outer side arc surface of the crescent plate and the center line of the driving wheel are on the same plane.

[0015] As preferred, the internal gear is clearance fitted with the inner wall of the pump body.

[0016] As preferred, the pump body is provided with an oil suction port and an oil discharge port, the oil suction port communicates with the oil suction cavity, and the oil discharge port communicates with the oil discharge cavity.

[0017] As preferred, the pump further comprises a pump cover connected with the pump body, the pump cover is arranged on the pump body through an internal hexagonal screw, the pump cover is provided with a shaft hole, and a labyrinth seal part is arranged on the inner wall of the shaft hole. The labyrinth seal part improves the sealing performance of the shaft hole.

[0018] As preferred, the pump further comprises a shell and an end cover, the pump body and the pump cover are arranged in the shell and the end cover, and the pump cover and the shell are connected through an elastic pin.

[0019] As preferred, the labyrinth seal part is composed of a plurality of annular grooves, and the annular grooves are distributed along the center line of the shaft hole. The plurality of annular grooves improve the sealing performance of the shaft hole.

[0020] As preferred, the shell is provided with a drain hole and a lubricating oil hole. The shell is provided with a lubricating hole, and the lubricating hole communicates with the oil discharge space of the drain hole. The oil can also be delivered to the required lubricating part, the friction resistance of the corresponding part is reduced, and the service life of the oil pump is improved.

[0021] Therefore, the utility model has following beneficial effect: through the crescent board inside arc surface and pump body inner wall offset setting, greatly improve the lubrication performance between crescent board and internal and external gear, internal gear and pump inner wall, it is favorable to greatly delay the wear and tear between crescent board, driving wheel, internal gear and pump body inner wall, thereby effectively prolong the service life of internal meshing gear pump. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a sectional view of the utility model embodiment two.

[0023] Figure 2 It is a sectional view of the utility model embodiment three.

[0024] Figure 3 It is another sectional view of the utility model embodiment two.

[0025] Figure 4 It is a partial sectional view of the utility model embodiment two.

[0026] Figure 5 It is a structural schematic diagram of the utility model embodiment two.

[0027] As shown in the figure:

[0028] Pump body 1, oil suction port 1.1, oil pressure port 1.2,

[0029] Internal gear 2, driving wheel 3, crescent board 4, oil suction chamber 5, oil pressure chamber 6,

[0030] Pump cover 7, shaft hole 7.1, labyrinth seal part 7.2,

[0031] Shell 8, oil drain hole 8.1, lubricating oil hole 8.2,

[0032] End cover 9, elastic pin 10,

[0033] Driving wheel center P0, crescent board inside arc surface center P1, crescent board outside arc surface center P2,

[0034] Internal gear center P3, shell inner wall center P4. DETAILED DESCRIPTION

[0035] In order to make the utility model technical scheme embodiment purpose, technical scheme and advantage more clearly, the utility model is further described below with the specific embodiment to the attached drawing.

[0036] Embodiment one, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5The self-lubricating internal gear pump shown in the figure comprises a pump body 1, an internal gear 2 and a driving wheel 3 offset engaged in the internal gear 2 are arranged in the pump body 1, a cavity between the internal gear 2 and the driving wheel 3 is separated into an oil suction cavity 5 and an oil compression cavity 6 by a crescent plate 4, an inner arc surface of the crescent plate 4 is in clearance fit with the driving wheel 3, and a center line of the inner arc surface of the crescent plate 4 is offset relative to a center line of the driving wheel 3 towards the oil suction cavity 5; a center line of an inner wall of the pump body 1 is offset relative to a center line of the internal gear 2 towards the oil suction cavity 5.

[0037] The internal gear pump has the advantages of compact structure, small flow pulsation, high pressure, low noise, good self-priming performance, large speed range, etc., and comprises a pair of external gears and internal gears 2 with involute tooth profile engaged with each other, the external gear is a driving wheel 3, the internal gear 2 is a driven wheel, and the oil suction cavity 5 and the oil compression cavity 6 are separated by the crescent plate 4, the two gears rotate in the same direction, the teeth entering the oil suction cavity 5 exit the engagement, so that the volume of the oil suction cavity 5 increases, a vacuum is formed, and the oil is sucked in under the action of atmospheric pressure, and the two gears carry the oil in the oil suction cavity 5 into the oil compression cavity 6; the gears entering the oil compression cavity 6 enter the engagement, the volume of the oil compression cavity 6 decreases, and the oil is pressed out, completing the oil discharge process. In actual application, due to the hydraulic pressure of the oil and the gear engagement force on the internal gear 2, the internal gear 2 generates pressure on the inner wall of the pump body 1, causing wear, and the contact surface between the inner arc surface of the crescent plate 4 and the driving wheel 3 wears quickly, reducing the stability and service life of the internal gear pump.

[0038] In order to solve the problem of large wear between the internal gear 2 and the inner wall of the pump body 1 and the contact surface between the inner arc surface of the crescent plate 4 and the driving wheel 3 in the existing internal gear pump, which reduces the stability and service life of the internal gear pump, a self-lubricating internal gear pump with self-lubricating performance is provided to improve the stability and service life of the internal gear pump.

[0039] The self-lubricating internal gear pump in the embodiment greatly improves the lubricating performance between the crescent plate 4 and the internal and external gears and between the internal gear 2 and the inner wall of the pump by offsetting the inner arc surface of the crescent plate 4 and the inner wall of the pump body 1, thereby improving the service life of the internal gear pump.

[0040] Due to the combined force of the hydraulic pressure of the oil and the gear meshing force on the internal gear 2, the internal gear 2 generates a large pressure on the inner wall of the pump body 1 in the direction of the oil suction cavity 5, causing the gap between the internal gear 2 on the side of the oil suction cavity 5 and the inner wall of the pump body 1 to be smaller than the gap between the internal gear 2 on the side of the oil pressure cavity 6 and the inner wall of the pump body 1, reducing the lubrication performance and causing adhesive friction between the internal gear 2 and the inner wall of the pump body 1, which leads to the insertion of the internal gear 2 and the pump body 1 to be glued, and then causes the internal meshing gear pump to fail. In the technical solution, the center line of the inner wall of the pump body 1 is offset towards the oil suction cavity 5 relative to the center line of the internal gear 2, so that the gap between the internal gear 2 on the side of the oil suction cavity 5 and the inner wall of the pump body 1 is larger than the gap between the internal gear 2 on the side of the oil pressure cavity 6 and the inner wall of the pump body 1. On the one hand, it causes the internal gear 2 and the inner wall of the pump body 1 to generate dynamic lubrication effect, improving the lubrication performance between the internal gear 2 and the inner wall of the pump body 1; on the other hand, it avoids the problem of the internal gear 2 generating a large pressure on the inner wall of the pump body 1 due to the combined force of the hydraulic pressure of the oil and the gear meshing force, reducing the wear and gluing between the internal gear 2 and the pump body 1.

[0041] By offsetting the center line of the inner wall of the pump body 1 towards the oil suction cavity 5 relative to the center line of the internal gear 2, the gap between the outer arc surface of the crescent plate 4 and the internal gear 2 gradually decreases from the oil suction cavity 5 to the oil pressure cavity 6 during the operation of the internal gear ring under high speed and high oil pressure conditions, forming a converging gap oil wedge structure between the outer arc surface of the crescent plate 4 and the internal gear 2, increasing the dynamic lubrication effect between the outer arc surface of the crescent plate 4 and the internal gear 2, and improving the lubrication performance and reducing the wear between the crescent plate 4 and the internal gear 2.

[0042] Due to the fast wear of the contact surface between the inner arc surface of the crescent plate 4 and the driving wheel 3, in the technical solution, the center line of the inner arc surface of the crescent plate 4 is offset towards the oil suction cavity 5 relative to the center line of the driving wheel 3, so that the gap between the inner arc surface of the crescent plate 4 and the driving wheel 3 gradually decreases from the oil suction cavity 5 to the oil pressure cavity 6, forming a converging gap oil wedge structure between the inner arc surface of the crescent plate 4 and the driving wheel 3, increasing the dynamic lubrication effect between the inner arc surface of the crescent plate 4 and the driving wheel 3, and improving the lubrication performance and reducing the wear between the crescent plate 4 and the driving wheel 3.

[0043] In the technical solution, the center line of the inner arc surface of the crescent plate 4 is offset towards the oil suction cavity 5 relative to the center line of the driving wheel 3 and the center line of the inner wall of the pump body 1 is offset towards the oil suction cavity 5 relative to the center line of the internal gear 2, so that self-lubrication performance is generated between the crescent plate 4 and the driving wheel 3, between the crescent plate 4 and the internal gear 2, and between the internal gear 2 and the inner wall of the pump body 1, reducing the wear of the internal meshing gear pump and improving the stability and service life of the internal meshing gear pump.

[0044] In the technical solution, the center line of the inner arc surface of the crescent plate 4 is offset towards the oil suction cavity 5 relative to the center line of the driving wheel 3 and the center line of the inner wall of the pump body 1 is offset towards the oil suction cavity 5 relative to the center line of the internal gear 2, so that self-lubrication performance is generated between the crescent plate 4 and the driving wheel 3, between the crescent plate 4 and the internal gear 2, and between the internal gear 2 and the inner wall of the pump body 1, reducing the wear of the internal meshing gear pump and improving the stability and service life of the internal meshing gear pump. Figure 1 , Figure 3 ,Figure 4 、 Figure 5 The self-lubricating internal gear pump shown in the drawings comprises a pump body 1, an internal gear 2 and a driving wheel 3 offset engaged in the internal gear 2 are arranged in the pump body 1, the cavity between the internal gear 2 and the driving wheel 3 is divided into an oil suction cavity 5 and an oil pressing cavity 6 by a crescent plate 4, the inner arc surface of the crescent plate 4 is in clearance fit with the driving wheel 3, and the center line of the inner arc surface of the crescent plate 4 is offset towards the oil suction cavity 5 relative to the center line of the driving wheel 3; the center line of the inner wall of the pump body 1 is offset towards the oil suction cavity 5 relative to the center line of the internal gear 2.

[0045] The crescent plate 4 is further optimized, as shown in Figure 1 、 Figure 3 、 Figure 4 、 Figure 5 The angle between the plane formed by the center line of the inner arc surface of the crescent plate 4 and the center line of the driving wheel 3 and the plane formed by the center line of the inner wall of the pump body 1 and the center line of the internal gear 2 is an acute angle. The lubrication performance is optimized.

[0046] In this embodiment, as shown in Figure 1 、 Figure 3 、 Figure 4 、 Figure 5 The internal gear 2 is in clearance fit with the inner wall of the pump body 1.

[0047] Specifically, as shown in Figure 1 、 Figure 3 、 Figure 4 、 Figure 5 The pump body 1 is provided with an oil suction port 1.1 and an oil pressing port 1.2, the oil suction port 1.1 communicates with the oil suction cavity 5, and the oil pressing port 1.2 communicates with the oil pressing cavity 6. Further comprising a pump cover 7 connected with the pump body 1, the pump cover 7 is arranged on the pump body 1 through an internal hexagonal screw, the pump cover 7 is provided with a shaft hole 7.1, and the inner wall of the shaft hole 7.1 is provided with a labyrinth seal part 7.2. The labyrinth seal part 7.2 improves the sealing performance of the shaft hole 7.1. Further comprising a shell 8 and an end cover 9, the pump body 1 and the pump cover 7 are arranged in the shell 8 and the end cover 9, and the pump cover 7 and the shell 8 are connected through an elastic pin 10. The labyrinth seal part 7.2 is composed of a plurality of annular grooves, and the annular grooves are distributed along the center line of the shaft hole 7.1. The plurality of annular grooves improve the sealing performance of the shaft hole 7.1. The shell 8 is provided with a drain hole 8.1 and a lubricating oil hole 8.2. The shell 8 is provided with a lubricating hole, and the lubricating hole communicates with the drain space of the drain hole 8.1. The drain oil can also deliver oil to the required lubricating part, reduce the friction resistance of the corresponding part, and improve the service life of the oil pump.

[0048] As shown in Figure 1 、 Figure 3 、 Figure 4 、 Figure 5As shown, this embodiment has the following beneficial effects: by offsetting the inner arc surface of the crescent plate 4 and the inner wall of the pump body 1, the lubrication performance between the crescent plate 4 and the inner and outer gears, and between the internal gear 2 and the inner wall of the pump is greatly improved, which is conducive to significantly delaying the wear between the crescent plate 4, the driving wheel 3, the internal gear 2 and the inner wall of the pump body 1, thereby effectively extending the service life of the internal gear pump.

[0049] Example 3, as Figure 2 The self-lubricating internal gear pump shown includes a pump body 1, which is equipped with an internal gear 2 and a driving wheel 3 that is offset and meshed with the internal gear 2. The cavity between the internal gear 2 and the driving wheel 3 is divided into an oil suction chamber 5 and an oil pressure chamber 6 by a crescent plate 4. The inner arc surface of the crescent plate 4 has a clearance fit with the driving wheel 3, and the centerline of the inner arc surface of the crescent plate 4 is offset toward the oil suction chamber 5 relative to the centerline of the driving wheel 3. The centerline of the inner wall of the pump body 1 is offset toward the oil suction chamber 5 relative to the centerline of the internal gear 2. The outer arc surface of the crescent plate 4 has a clearance fit with the internal gear 2, and the centerline of the outer arc surface of the crescent plate 4 is offset toward the oil pressure chamber 6 relative to the centerline of the driving wheel 3.

[0050] The principle of this embodiment: Figure 2 As shown, in the present technical solution, the center line of the inner wall of the pump body 1 is offset toward the oil suction chamber 5 relative to the center line of the internal gear 2, so that the gap between the internal gear 2 on the oil suction chamber 5 side and the inner wall of the pump body 1 is larger than the gap between the internal gear 2 on the oil pressure chamber 6 side and the inner wall of the pump body 1. On the one hand, a dynamic lubrication effect is generated between the internal gear 2 and the inner wall of the pump body 1, thereby improving the lubrication performance between the internal gear 2 and the inner wall of the pump body 1; on the other hand, the problem of the internal gear 2 being subjected to a large pressure on the inner wall of the pump body 1 caused by the combined force of the liquid pressure of the oil and the gear meshing force is avoided, thereby reducing the wear and bonding problems between the internal gear 2 and the pump body 1.

[0051] By offsetting the center line of the inner wall of the pump body 1 relative to the center line of the internal gear 2 toward the oil suction chamber 5, when the internal gear ring is operating under high speed and high oil pressure conditions, a structure is formed in which the gap between the outer arc surface of the crescent plate 4 and the internal gear 2 gradually decreases from the oil suction chamber 5 toward the oil pressure chamber 6. An oil wedge structure with a convergent gap is formed between the outer arc surface of the crescent plate 4 and the internal gear 2, which increases the dynamic lubrication effect between the outer arc surface of the crescent plate 4 and the internal gear 2, thereby improving the lubrication performance and reducing wear between the crescent plate 4 and the internal gear 2.

[0052] Ensure that similar convergent gap oil wedge structures are formed between the crescent plate 4 and the driving wheel 3, as well as between the crescent plate 4 and the internal gear 2, and all produce self-lubricating properties, reduce the wear of the crescent plate 4, the driving wheel 3, and the internal gear 2, and improve the stability and service life of the internal gear pump.

[0053] Further optimization of the crescent plate 4, such as Figure 2As shown, the center line of the inner arc surface of the crescent plate 4, the center line of the outer arc surface of the crescent plate 4 and the center line of the driving wheel 3 are on the same plane.

[0054] The crescent plate 4 is further optimized, as shown in the figure. Figure 2 As shown, the plane formed by the center line of the inner arc surface of the crescent plate 4 and the center line of the driving wheel 3 forms an acute angle with the plane formed by the center line of the inner wall of the pump body 1 and the center line of the inner gear 2. The lubrication performance is optimized.

[0055] In this embodiment, as shown in the figure. Figure 2 The inner gear 2 is in clearance fit with the inner wall of the pump body 1.

[0056] The pump body 1 is further optimized, as shown in the figure. Figure 2 As shown, the pump body 1 is provided with an oil suction port 1.1 and an oil discharge port 1.2, the oil suction port 1.1 communicates with the oil suction chamber 5, and the oil discharge port 1.2 communicates with the oil discharge chamber 6. It also includes a pump cover 7 connected to the pump body 1, the pump cover 7 is arranged on the pump body 1 through an internal hexagonal screw, the pump cover 7 is provided with a shaft hole 7.1, and the inner wall of the shaft hole 7.1 is provided with a labyrinth seal part 7.2. The labyrinth seal part 7.2 improves the sealing performance of the shaft hole 7.1. It also includes a shell 8 and an end cover 9, the pump body 1 and the pump cover 7 are arranged in the shell 8 and the end cover 9, and the pump cover 7 and the shell 8 are connected through an elastic pin 10. The labyrinth seal part 7.2 is composed of a plurality of annular grooves, and the annular grooves are distributed along the center line of the shaft hole 7.1. The plurality of annular grooves improve the sealing performance of the shaft hole 7.1. The shell 8 is provided with a drain hole 8.1 and a lubricating oil hole 8.2. The shell 8 is provided with a lubricating hole, which communicates with the drain space of the drain hole 8.1. The drain oil can also deliver oil to the required lubricating part, reduce the friction resistance of the corresponding part, and improve the service life of the oil pump.

[0057] As shown in the figure, Figure 2 The embodiment has the following beneficial effects: through the offset arrangement of the inner arc surface of the crescent plate 4 and the inner wall of the pump body 1, the lubrication performance between the crescent plate 4 and the inner and outer gears, and between the inner gear 2 and the inner wall of the pump is greatly improved, which is conducive to greatly delaying the wear between the crescent plate 4, the driving wheel 3, the inner gear 2 and the inner wall of the pump body 1, thereby effectively prolonging the service life of the internal gear pump.

[0058] The above-described specific embodiments are only the preferred embodiments of the utility model, and do not limit the specific implementation range of the utility model. Any equivalent changes made in accordance with the shape and structure of the utility model should be included in the protection scope of the utility model.

Claims

1. A self-lubricating internal gear pump, comprising a pump body, an internal gear and a driving wheel offsetly meshed with the internal gear, wherein the cavity between the internal gear and the driving wheel is divided into an oil suction cavity and an oil pressure cavity by a crescent plate, wherein: The inner arc surface of the crescent plate is matched with the gap of the driving wheel, and the center line of the inner arc surface of the crescent plate is offset to the oil suction cavity relative to the center line of the driving wheel; the center line of the inner wall of the pump body is offset to the oil suction cavity relative to the center line of the internal gear.

2. A self-lubricating internal gear pump according to claim 1, characterized in that The included angle between the plane formed by the center line of the inner arc surface of the crescent plate and the center line of the driving wheel and the plane formed by the center line of the inner wall of the pump body and the center line of the internal gear is an acute angle.

3. A self-lubricating internal gear pump according to claim 1 or 2, characterized in that The outer arc surface of the crescent plate is matched with the gap of the internal gear, and the center line of the outer arc surface of the crescent plate is offset to the oil compression cavity relative to the center line of the driving wheel.

4. A self-lubricating internal gear pump according to claim 3, characterized in that The center line of the inner arc surface of the crescent plate, the center line of the outer arc surface of the crescent plate and the center line of the driving wheel are on the same plane.

5. A self-lubricating internal gear pump according to claim 1 or 2, characterized in that The internal gear is matched with the gap of the inner wall of the pump body.

6. A self-lubricating internal gear pump according to claim 1 or 2, characterized in that The pump body is provided with an oil suction port and an oil compression port, the oil suction port is communicated with the oil suction cavity, and the oil compression port is communicated with the oil compression cavity.

7. A self-lubricating internal gear pump according to claim 6, characterized in that Further comprising a pump cover connected with the pump body, the pump cover is arranged on the pump body through an internal hexagonal screw, the pump cover is provided with a shaft hole, and the inner wall of the shaft hole is provided with a labyrinth seal part.

8. A self-lubricating internal gear pump according to claim 7, characterized in that Further comprising a shell and an end cover, the pump body and the pump cover are arranged in the shell and the end cover, and the pump cover and the shell are connected through an elastic pin.

9. A self-lubricating internal gear pump according to claim 8, characterized in that The labyrinth seal part is composed of a plurality of annular grooves, and the annular grooves are distributed along the center line of the shaft hole.

10. A self-lubricating internal gear pump according to claim 9, characterized in that The shell is provided with an oil leakage hole and a lubricating oil hole.

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