An internal gear pump

Abstract

The embodiment of the present application relates to the field of gear pumps, and discloses an internal gear pump, which comprises a shell provided with a cavity, an oil suction port and an oil outlet port, the oil suction port and the oil outlet port being communicated with the cavity respectively; an inner gear ring rotatably accommodated in the cavity and abutting against the inner wall of the cavity; a gear shaft at least partially accommodated in the cavity, the gear shaft being eccentrically engaged with the inner gear ring; and a crescent-shaped body arranged between the inner gear ring and the gear shaft, the crescent-shaped body separating the cavity into an oil suction cavity and an oil pressing cavity, wherein the inner wall of the shell is provided with an oil introduction channel, the oil introduction channel being communicated with the oil pressing cavity. The high-pressure medium in the oil pressing cavity is introduced into the inner wall of the shell through the oil introduction channel, and a thrust from outside to inside is applied to the inner gear ring, the thrust offsetting a part of the thrust from inside to outside applied to the inner gear ring by the high-pressure medium in the oil pressing cavity, so that the amount of the inner gear ring deviating towards the shell during high-speed rotation is reduced, and the noise generated by the inner gear ring during high-speed rotation is reduced.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the field of gear pumps, in particular to an internal meshing gear pump. BACKGROUND

[0002] The internal meshing gear pump adopts the principle of internal meshing of gears, the pitch circles of the internal and external gears are close to one side, and the other side is separated by a crescent plate on the pump cover. The driving internal gear on the main shaft drives the internal and external gears to rotate in the same direction, the gears are separated from each other at the inlet to form negative pressure to suck in liquid, and the gears are continuously meshed at the outlet to extrude and output the liquid. In the existing internal meshing gear pump, a pressure balance groove or an oil groove is generally arranged in the shell to inhibit the leakage of working oil from the inner teeth of the external rotor and the outer teeth of the internal rotor.

[0003] However, the present inventors have noticed that when the internal meshing gear pump with the above structure operates at a high speed, although the leakage is inhibited, the noise and the sound quality change obviously, and the sound quality will be relatively sharp, and the noise is mainly generated by the interference between the inner teeth of the gear ring and the crescent plate. SUMMARY

[0004] The embodiment of the present application provides an internal meshing gear pump, which aims to solve the problem of large noise in the operation process of the internal meshing gear pump.

[0005] To solve the above technical problems, one technical scheme adopted by the present application is to provide an internal meshing gear pump, which comprises:

[0006] A shell is provided with a cavity, an oil suction port and an oil outlet port, and the oil suction port and the oil outlet port are respectively communicated with the cavity;

[0007] An internal gear ring is rotatably accommodated in the cavity and abuts against the inner wall of the cavity;

[0008] A gear shaft is at least partially accommodated in the cavity, and the gear shaft is eccentrically engaged with the internal gear ring;

[0009] A crescent-shaped body is arranged between the internal gear ring and the gear shaft, the crescent-shaped body separates the cavity into an oil suction cavity and an oil pressing cavity, the oil suction cavity is communicated with the oil suction port, and the oil pressing cavity is communicated with the oil outlet port;

[0010] The inner wall of the shell is provided with an oil introduction channel, and the oil introduction channel is communicated with the oil pressing cavity.

[0011] Optionally, the crescent-shaped body separates the cavity into a low-pressure area, a high-pressure area, and a pressure-increasing area, the low-pressure area and the high-pressure area are located on two sides of the crescent-shaped body respectively, the boundary of the low-pressure area along the radial direction of the inner gear ring is defined by a line from the center of the gear shaft to one side of the crescent-shaped body and a line from the center of the gear shaft to the meshing position of the outer teeth and the inner teeth; the boundary of the high-pressure area along the radial direction of the inner gear ring is defined by a line from the center of the gear shaft to the other side of the crescent-shaped body and a line from the center of the gear shaft to the meshing position of the outer teeth and the inner teeth, the oil introduction channel is located in the high-pressure area; the pressure-increasing area is located between the high-pressure area and the low-pressure area.

[0012] Optionally, the oil introduction channel includes a first section, a second section, and a third section, the first section is in communication with the oil press chamber, the third section is in communication with the inner wall of the housing; the second section is located between the first section and the third section, the aperture of the second section is smaller than the aperture of the first section and the aperture of the third section.

[0013] Optionally, the aperture of the second section is less than or equal to 1mm, or the cross-sectional area of the second section is less than or equal to 3.14mm2.

[0014] Optionally, the oil press chamber is separated into a first chamber and a second chamber by the inner gear ring and the gear shaft, the first chamber and the second chamber are located on two sides of the inner gear ring along the axial direction respectively, the first chamber or the second chamber is in communication with the oil outlet.

[0015] Optionally, the oil inlet of the oil introduction channel is in communication with the first chamber and / or the second chamber.

[0016] Optionally, the oil introduction channel is arranged close to the crescent-shaped body.

[0017] Optionally, the inner wall of the cavity is provided with a groove corresponding to the area where the oil press chamber is located, the groove extends along the axial direction of the gear ring.

[0018] Optionally, the groove is arranged away from the crescent-shaped body.

[0019] Optionally, the oil pressure in the groove is less than the oil pressure in the oil press chamber.

[0020] Optionally, the aperture of the oil outlet is smaller than the aperture of the oil suction port.

[0021] The beneficial effects of the embodiment of the present application are as follows: Different from the prior art, the inner meshing gear pump in the present application comprises a shell, an inner gear ring, a gear shaft and a crescent-shaped body. The shell is provided with a cavity, an oil suction port and an oil outlet port. The oil suction port is located on one side of the shell in the axial direction, and the oil suction port is in communication with the cavity. The oil outlet port is located on the other side of the shell in the axial direction, and the oil outlet port is in communication with the cavity. The inner wall of the inner gear ring is provided with gear teeth. The inner gear ring is rotatably accommodated in the cavity, and the inner gear ring abuts against the inner wall of the cavity. The gear shaft is at least partially accommodated in the cavity, and the part of the gear shaft accommodated in the cavity penetrates through the inner gear ring. The axis of the gear shaft does not coincide with the axis of the inner gear ring, and the gear shaft is provided with gear teeth corresponding to the inner gear ring. The gear teeth of the gear shaft and the gear teeth of the inner gear ring are in meshing relationship. The crescent-shaped body is fixedly arranged between the inner gear ring and the gear shaft, and the crescent-shaped body divides the cavity into an oil suction cavity and an oil pressing cavity. The oil suction cavity and the oil pressing cavity are respectively located at the two ends of the crescent-shaped body. The inner wall of the shell is provided with an oil introduction channel, and the oil introduction channel is in communication with the oil pressing cavity. The oil introduction channel can introduce the high-pressure medium in the oil pressing cavity to the inner wall of the shell. The medium introduced by the oil introduction channel acts on the outer contour of the inner gear ring and applies an outward pushing force to the inner gear ring. The pushing force offsets a part of the inward pushing force applied to the inner gear ring by the high-pressure medium in the oil pressing cavity, thereby reducing the amount of deflection of the inner gear ring towards the shell when rotating at high speed, and further reducing the noise generated by the inner gear ring when rotating at high speed. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed to be used in the following specific embodiment or prior art description will be briefly introduced. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, various elements or parts are not necessarily drawn according to the actual proportions.

[0023] Figure 1 is an axial sectional view of the inner meshing gear pump in an embodiment of the present application;

[0024] Figure 2 is a D-D sectional view of Figure 1 ;

[0025] Figure 3 is an E-E sectional view of Figure 2 in an embodiment of the present application;

[0026] Figure 4 is an E-E sectional view of Figure 2 in another embodiment of the present application;

[0027] Figure 5 is an enlarged schematic view of the P part in Figure 2 ;

[0028] Figure 6 is a schematic view of the local structure of the inner meshing gear pump in an embodiment of the present application.

[0029] BRIEF DESCRIPTION OF DRAWINGS

[0030] 100, internal gear pump; 1, housing; 11, front cover; 12, rear shell; 13, cavity; 131, oil pressing cavity; 1311, first chamber; 1312, second chamber; 132, oil suction cavity; 1321, third chamber; 1322, fourth chamber; 14, oil suction port; 15, oil outlet port; 16, oil introduction path; 161, first section; 162, second section; 163, third section; 164, oil inlet port; 165, oil outlet port; 17, groove; 2, inner ring gear; 21, inner teeth; 3, gear shaft; 31, shaft part; 32, gear part; 321, outer teeth; 4, crescent body; 41, oil conveying groove; 5, first bearing; 6, second bearing. DETAILED DESCRIPTION

[0031] For the purpose of promoting the understanding of the present application, the present application will be described in further detail below with reference to the drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element or one or more intervening elements can be present therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element or one or more intervening elements can be present therebetween. The terms "vertical", "horizontal", "left", "right", and similar expressions used in the present specification are for the purpose of illustration only.

[0032] Unless otherwise defined, all technical and scientific terms used in the present specification are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in the description of the application herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0033] Referring to Figures 1 to 3 The present application provides an internal gear pump 100, which comprises a housing 1, an inner ring gear 2, a gear shaft 3, and a crescent body 4.

[0034] The shell 1 is substantially cylindrical, and the shell 1 is internally provided with a cavity 13, an oil suction port 14 and an oil outlet 15. The cavity 13 has a preset shape, which means that the shape of the cavity 13 needs to meet the installation of other parts. The oil suction port 14 is located on one side of the shell 1 in the axial direction, and the oil suction port 14 is in communication with the cavity 13. The oil suction port 14 is used to deliver medium into the cavity 13, and the type of medium includes but is not limited to Newtonian liquid or non-Newtonian liquid in the oil, chemical, paint, dye, food, grease, medicine and other industries, and the type of delivered liquid can be from light, volatile liquid to heavy, viscous, even semi-solid liquid. The oil outlet 15 is located on the other side of the shell 1 in the axial direction, and the oil outlet 15 is in communication with the cavity 13. The oil outlet 15 is used to output medium with a certain pressure, specifically, the medium entering the cavity 13 from the oil suction port 14 is discharged from the oil outlet 15 after being pressurized.

[0035] The aperture of the oil outlet 15 is smaller than that of the oil suction port 14, which facilitates rapid pressure establishment and thus rapid discharge of the medium. At the same time, the medium can be better stored in the cavity 13, which facilitates the formation of an oil film and better vacuum self-suction during the next start-up.

[0036] The inner ring gear 2 is substantially annular, and the inner wall of the inner ring gear 2 is provided with inner teeth 21. The inner ring gear 2 is rotatably accommodated in the cavity 13, and the outer wall of the inner ring gear 2 abuts against the inner wall of the cavity 13.

[0037] The gear shaft 3 is substantially cylindrical, at least partially accommodated in the cavity 13, and the gear shaft 3 penetrates the inner ring gear 2. The axis of the gear shaft 3 does not coincide with the axis of the inner ring gear 2, that is, the gear shaft 3 is eccentrically arranged relative to the inner ring gear 2. The part of the gear shaft 3 corresponding to the inner ring gear 2 is provided with outer teeth 321, and the outer teeth 321 of the gear shaft 3 and the inner teeth 21 of the inner ring gear 2 are in meshing relationship. The number of the inner teeth 21 is more than that of the outer teeth 321. One end of the gear shaft 3 is connected with a power source outside, that is, the power source outside can drive the gear shaft 3 to rotate and drive the inner ring gear 2 to rotate. Due to the eccentric arrangement of the gear shaft 3, part of the teeth of the gear shaft 3 and part of the teeth of the inner ring gear 2 are in meshing relationship at the S point, and with the rotation of the gear shaft 3, the teeth of the gear shaft 3 and the inner ring gear 2 gradually separate, and at the same time, new teeth of the gear shaft 3 gradually enter into meshing relationship with the teeth of the inner ring gear 2, that is, the specific teeth of the gear shaft 3 and the inner ring gear 2 at the S point are in dynamic change.

[0038] The crescent-shaped body 4 is substantially crescent-shaped, and has two arc surfaces. The crescent-shaped body 4 is fixed between the inner gear ring 2 and the gear shaft 3, and the two arc surfaces of the crescent-shaped body 4 are in contact with the inner teeth 21 of the inner gear ring 2 and the outer teeth 321 of the gear shaft 3 respectively. The crescent-shaped body 4 divides the cavity 13 into an oil suction cavity 132 and an oil compression cavity 131, and the oil suction cavity 132 and the oil compression cavity 131 are located on the two sides of the crescent-shaped body 4 along the radial direction of the gear shaft 3. Since the gear shaft 3 and the inner gear ring 2 always have part of the teeth in meshing state (at point S), point S is the demarcation point between the oil suction cavity 132 and the oil compression cavity 131. The crescent-shaped body 4 and the outer teeth 321 form an oil conveying groove 41, which conveys the medium from the oil suction cavity 132 to the oil compression cavity 131.

[0039] Please refer to Figure 2 In this embodiment, the gear shaft 3 rotates clockwise, and point S is substantially located at the opposite side of the crescent-shaped body 4. Starting from the crescent-shaped body 4, the oil compression cavity 131 and the oil suction cavity 132 are sequentially arranged in the clockwise direction. It should be noted that when the gear shaft 3 rotates counterclockwise, the positions of the oil compression cavity 131 and the oil suction cavity 132 are interchanged.

[0040] The specific area boundaries of the oil compression cavity 131 and the oil suction cavity 132 are as follows: for ease of description, an auxiliary circle is drawn with the center point O of the gear shaft 3. A straight line OA is drawn from the center point O to the end point of the crescent-shaped body 4 close to the oil compression cavity 131 and is extended to intersect the auxiliary circle at point A. A straight line OC is drawn from the center point O to the end point of the crescent-shaped body 4 close to the oil suction cavity 132 and is extended to intersect the auxiliary circle at point C. A straight line OB is drawn from the center point O to point S and is extended to intersect the auxiliary circle at point B. The oil compression cavity 131 is the area surrounded by the straight line OA, the straight line OB, the edge of the outer teeth of the gear shaft 3 and the edge of the inner teeth of the inner gear ring 2. The oil suction cavity 132 is the area surrounded by the straight line OB, the straight line OC, the edge of the outer teeth of the gear shaft 3 and the edge of the inner teeth of the inner gear ring 2.

[0041] According to the pressure, the area corresponding to the oil compression cavity 131 is a high-pressure area, the area corresponding to the oil suction cavity 132 is a low-pressure area, and the area of the gap between the crescent-shaped body 4 and the gear shaft 3 (the overlapping part of the fan-shaped area AOC of the cavity 13) is a pressure-increasing area. Among them, the pressure of the high-pressure area is greater than the pressure of the pressure-increasing area, and the pressure of the pressure-increasing area is greater than the pressure of the low-pressure area.

[0042] In the high pressure area, the high pressure medium in the pressure oil cavity 131 pushes the inner ring gear 2 to the side of the housing 1. For the convenience of description, the side of the inner ring gear 2 facing the gear shaft 3 is referred to as the inner side, and the side of the inner ring gear 2 away from the gear shaft 3 is referred to as the outer side. The high pressure medium in the pressure oil cavity 131 provides the inner ring gear 2 with a first outward thrust F1, causing the position of the inner ring gear 2 to shift slightly, resulting in the inner ring gear 2 being pressed against the inner wall of the cavity 13 of the housing 1 when rotating, and possibly causing the tooth tips of the inner ring gear 2 to rub against the surface of the crescent-shaped body 4, producing sharp noise.

[0043] Referring to Figures 2 to 4 The inner wall of the housing 1 is provided with an oil introduction passage 16, which is in communication with the pressure oil cavity 131. The end of the oil introduction passage 16 in communication with the pressure oil cavity 131 is provided with an oil inlet 164, and the end of the oil introduction passage 16 in communication with the inner wall of the housing 1 is provided with an oil outlet 165. The oil introduction passage 16 can introduce the high pressure medium in the pressure oil cavity 131 between the inner wall of the housing 1 and the outer wall of the inner ring gear 2. The high pressure medium introduced by the oil introduction passage 16 can exert a second inward thrust F2 on the inner ring gear 2, which can offset a portion of the first thrust F1 exerted on the inner ring gear 2 by the high pressure medium in the pressure oil cavity 131, thereby reducing the amount of displacement of the inner ring gear 2 towards the housing 1 when rotating at high speed, and further reducing the noise generated by the inner ring gear 2 when rotating at high speed.

[0044] Referring to Figures 2 to 4 In some embodiments, the oil introduction passage 16 includes a first section 161, a second section 162 and a third section 163. The first section 161 is in communication with the pressure oil cavity 131, and the third section 163 is in communication with the outer wall of the inner ring gear 2. The second section 162 is located between the first section 161 and the third section 163, and is in communication with the first section 161 and the third section 163, respectively. The aperture of the second section 162 is smaller than the apertures of the first section 161 and the third section 163, respectively. Therefore, when the high pressure medium in the pressure oil cavity 131 enters the cavity 13 along the oil introduction passage 16, it will pass through the relatively narrow second section 162.

[0045] When the inner ring 2 rotates at high speed, the oil film between the outer edge of the inner ring 2 and the inner wall of the housing 1 increases in pressure due to the oil wedge principle, resulting in a thrust from the outer edge of the inner ring 2 to the center of the inner ring 2, which increases with the increase of the rotating speed. When the thrust exceeds the thrust from the inside to the outside of the inner ring 2, the outer edge of the inner ring 2 moves towards the center of the rotation of the inner ring 2, and further causes the tooth top of the inner ring 2 to rub against the crescent-shaped body 4, resulting in sharp noise. The high-pressure medium flowing through the second section 162 is subjected to resistance, resulting in a decrease in pressure after the medium flows through the second section 162. The pressure of the medium output by the oil discharge port 165 of the introduction oil passage 16 can be adjusted, and further the thrust from the outer edge of the inner ring 2 to the center of the inner ring 2 due to the oil wedge principle when the inner ring 2 rotates at high speed can be reduced. For the above-mentioned second section 162, the smaller the diameter of the second section 162, the better the pressure reduction effect. Preferably, the diameter of the second section 162 is less than or equal to 1 mm, or the cross-sectional area of the second section 162 is less than or equal to 3.14 square millimeters, and the cross-sectional area of the second section 162 refers to the cross-sectional area along the radial direction of the second section 162. For the above-mentioned second section 162, the tightening manner of the second section 162 can be formed by machining or by inlaying a part with an elongated hole on the inner wall of the second section 162.

[0046] Referring to Figure 1 In some embodiments, the oil suction cavity 132 includes a third chamber 1321 and a fourth chamber 1322 in communication, the third chamber 1321 is located on one side of the axial direction of the inner ring 2, and the fourth chamber 1322 is located on the other side of the axial direction of the inner ring 2 and is arranged opposite to the third chamber 1321. The third chamber 1321 is in communication with the oil suction port 14. Since the third chamber 1321 and the fourth chamber 1322 are respectively located on both sides of the axial direction of the inner ring 2 and are respectively located at both ends of the radial direction of the inner ring 2 from the first chamber 1311 and the second chamber 1312, the axial pressure exerted by the high-pressure medium in the third chamber 1321 and the fourth chamber 1322 on the inner ring 2 can almost cancel each other out, so as to avoid displacement of the inner ring 2 due to the suction force on one side of the axial direction.

[0047] Referring to Figure 1 In some embodiments, the oil suction cavity 132 includes a third chamber 1321 and a fourth chamber 1322 in communication, the third chamber 1321 is located on one side of the axial direction of the inner ring 2, and the fourth chamber 1322 is located on the other side of the axial direction of the inner ring 2 and is arranged opposite to the third chamber 1321. The third chamber 1321 is in communication with the oil suction port 14. Since the third chamber 1321 and the fourth chamber 1322 are respectively located on both sides of the axial direction of the inner ring 2 and are respectively located at both ends of the radial direction of the inner ring 2 from the first chamber 1311 and the second chamber 1312, the axial pressure exerted by the high-pressure medium in the third chamber 1321 and the fourth chamber 1322 on the inner ring 2 can almost cancel each other out, so as to avoid displacement of the inner ring 2 due to the suction force on one side of the axial direction.

[0048] Referring to Figure 1 In some embodiments, the second chamber 1312 and the third chamber 1321 are respectively located on the two axial sides of the inner ring gear 2, i.e., the oil outlet 15 and the oil inlet 14 are respectively located on the two axial sides of the inner ring gear 2, so that the pressures on the two axial sides of the inner ring gear 2 are relatively balanced.

[0049] In some embodiments, the oil inlet 164 of the introduction oil passage 16 communicates with the first chamber 1311 and / or the second chamber 1312. Specifically, the specific structure of the introduction oil passage 16 can be any one of the following structures:

[0050] As shown in Figure 3 , the introduction oil passage 16 is provided with one, the introduction oil passage 16 is located inside the housing 1, the introduction oil passage 16 is distributed along the axial direction of the inner ring gear 2 and is arranged close to the inner ring gear 2, the oil inlet 164 of the introduction oil passage 16 communicates with the first chamber 1311, and the oil outlet 165 of the introduction oil passage 16 communicates with the second chamber 1312. Among them, the introduction oil passage 16 is formed by grooving the inner wall surface of the cavity 13 or the outer wall surface of the inner ring gear 2. Along the axial direction of the inner ring gear 2, the introduction oil passage 16 passes through the outer wall of the inner ring gear 2.

[0051] As shown in Figure 4 , the introduction oil passage 16 is provided with two, the two introduction oil passages 16 are both located inside the housing 1, one introduction oil passage 16 is located on one side of the inner ring gear 2 in the radial direction, and the other introduction oil passage 16 is located on the other side of the inner ring gear 2 in the radial direction. The oil inlets 164 of the two introduction oil passages 16 respectively communicate with the first chamber 1311 and the second chamber 1312, and the oil outlets 165 of the two introduction oil passages 16 are spaced apart and both communicate with the outer wall of the inner ring gear 2. Among them, the introduction oil passage 16 is formed by opening a channel on the housing, and the oil outlet 165 of the introduction oil passage 16 penetrates the inner wall surface and communicates with the outer wall of the inner ring gear 2.

[0052] It can be understood that in some other embodiments, Figure 4 As shown in , one of the two introduction oil passages 16 can be omitted, the oil inlet 164 of one introduction oil passage 16 communicates with the first chamber 1311 or the second chamber 1312, and the oil outlet 165 thereof communicates with the outer wall of the inner ring gear 2, as long as it can guide the medium in the oil pressure chamber 131 to the outer wall of the inner ring gear 2 and the inner wall of the cavity 13.

[0053] For the above introduction oil passage 16, it can be formed when the housing 1 is cast, or it can be formed after the housing 1 is cast.

[0054] Figure 1In some embodiments, the oil outlet 165 of the oil introduction passage 16 is located on the housing 1 corresponding to the oil pressure chamber 131, i.e. the oil outlet 165 of the oil introduction passage 16 is located on the inner wall of the housing 1 surrounding the oil pressure chamber 131, so as to provide the inner ring gear 2 with a force that can offset part of the outward pushing force applied to the inner ring gear 2 by the high-pressure medium in the oil pressure chamber 131.

[0055] Preferably, the oil outlet 165 of the oil introduction passage 16 is located close to the crescent-shaped body 4, so that the direction of the pressure provided to the inner ring gear 2 by the oil introduction passage 16 is completely opposite to the direction of the pushing force applied to the inner ring gear 2 by the high-pressure medium in the oil pressure chamber 131, so that the pressure provided to the inner ring gear 2 by the oil introduction passage 16 can better offset the pushing force applied to the inner ring gear 2 by the high-pressure medium.

[0056] When the inner ring gear 2 rotates at a high speed, although part of the outward pushing force generated by the inner ring gear 2 due to the working pressure of the oil pressure chamber 131 is offset by the high-pressure medium introduced from the oil introduction passage 16, because of the oil wedge principle, as the rotating speed of the inner ring gear 2 continuously increases, the pressure generated between the outer edge of the inner ring gear 2 and the inner wall of the corresponding housing 1 in the high-pressure area also continuously increases due to the oil wedge principle, and the inner ring gear 2 still cannot stably operate. Due to the oil wedge principle, the pressure is related to the rotating speed of the inner ring gear 2, and is also related to the gap between the outer edge of the inner ring gear 2 and the inner wall of the housing 1. Increasing the gap to a certain extent, the pushing force generated by the oil wedge will decrease.

[0057] Please refer to Figure 2 and Figure 5 In some embodiments, the inner wall of the cavity 13 is provided with a groove 17 corresponding to the area where the oil pressure chamber 131 is located, the groove 17 extends along the axial direction of the inner ring gear 2, and the groove 17 is not communicated with the oil pressure chamber 131. The setting of the groove 17 can increase the local gap between the outer edge of the inner ring gear 2 and the inner wall of the housing 1, reduce the generation of the oil wedge, and reduce the pressure of the oil film between the outer circumference of the inner ring gear 2 and the inner wall of the housing 1 due to the oil wedge principle. Therefore, the purpose of setting the groove 17 is to reduce and as far as possible fix the third outward pushing force F3 applied to the inner ring gear 2 due to the oil wedge principle at different rotating speeds, so as to make the inner ring gear 2 operate more stably.

[0058] It is worth mentioning that the above-mentioned increase of the local gap between the outer edge of the inner ring gear 2 and the inner wall of the housing 1 is not the gap generated by the size precision and the matching of the inner ring gear 2 and the inner wall of the housing 1, but is the gap generated by the processing of the groove 17 on the corresponding position of the inner wall of the housing 1.

[0059] For the above-mentioned groove 17, the cross section of the groove 17 can be semicircular or other irregular shapes. The length or depth of the groove 17 can be set according to actual requirements. The groove 17 can be provided in plurality, and the plurality of grooves 17 are arranged at intervals. The groove 17 can be formed when the shell 1 is cast, or can be formed after the shell 1 is cast. The structure, size, number and processing method of the groove 17 are not limited herein.

[0060] Referring to Figure 2 and Figure 5 In some embodiments, the groove 17 is arranged away from the crescent body 4. The groove 17 is arranged at intervals with the oil introduction passage 16, so that the groove 17 and the oil introduction passage 16 exert pressure from outside to inside on the inner ring gear 2 at two positions, which can improve the rotation stability of the inner ring gear 2. The groove 17 can be arranged close to the oil suction cavity 132.

[0061] Referring to Figure 2 and Figure 5 In some embodiments, since the groove 17 is not in communication with the oil press cavity 131, the high-pressure oil in the oil press cavity 131 will not be introduced into the groove 17. Since there is leakage from a high-pressure area to a low-pressure area during the operation of the internal gear pump 100, the oil leaked to the low-pressure area can enter between the outer wall of the inner ring gear 2 and the inner wall of the cavity 13 and enter the groove 17. The oil pressure in the groove 17 is less than the oil pressure in the oil press cavity 131, and the oil pressure in the groove 17 provides an auxiliary support for the inner ring gear 2. The pressure established by the groove 17 and the oil introduction passage 16 form two support points, which can make the rotation of the inner ring gear 2 more stable.

[0062] Referring to Figure 6 and Figure 2 In some embodiments, the gear shaft 3 includes a shaft portion 31 and a gear portion 32. The shaft portion 31 is cylindrical, and the axis of the shaft portion 31 is parallel to the axis of the inner ring gear 2. The shaft portion 31 is partially arranged in the shell 1, and one end of the shaft portion 31 extends to the outside of the shell 1 and is connected to an external power source. The gear portion 32 is arranged around the circumference of the shaft portion 31, and the gear portion 32 is connected to the shaft portion 31. The gear portion 32 corresponds to the inner ring gear 2. The external teeth are located on the gear portion 32 and are arranged along the circumference of the gear portion 32. The external power source can drive the shaft portion 31 to rotate, thereby driving the gear portion 32 and the inner ring gear 2 to rotate.

[0063] Referring to Figure 6 and Figure 2 In some embodiments, the internal gear pump 100 further includes a first bearing 5, which is accommodated in the cavity 13, and the axis of the first bearing 5 coincides with the axis of the gear shaft 3. The first bearing 5 is located on one side of the inner ring gear 2, and the first bearing 5 is sleeved on the gear shaft 3 to support the gear shaft 3.

[0064] The internal gear pump 100 also includes a second bearing 6, which is located on the other side of the internal gear ring 2 and is sleeved on the gear shaft 3 to support the gear shaft 3. The first bearing 5 and the second bearing 6 share the gear shaft 3, which can make the gear shaft 3 operate stably.

[0065] In some other embodiments, the gear shaft 3 described above is replaced by a structure in which a gear is fitted on the shaft portion.

[0066] Please see Figure 1 The aforementioned housing 1 includes a front cover 11 and a rear cover 12, which are connected and together form a cavity 13. An internal gear ring 2 is housed within the rear cover 12. One end of a gear shaft 3 with external teeth is housed within the rear cover 12, while the other end of the gear shaft 3 extends towards and through the front cover 11, and is connected to an external power source. Correspondingly, bearings are provided in both the front cover 11 and the rear cover 12, and the two ends of the gear shaft 3 are connected to the front cover 11 and the rear cover 12 respectively via bearings.

[0067] In this embodiment, the oil outlet 15 is located on the rear shell 12, and the oil suction port 14 is located on the front cover 11.

[0068] In summary, the present application provides an internal gear pump 100, which comprises a housing 1, an inner gear ring 2, a gear shaft 3 and a crescent-shaped body 4. The housing 1 is provided with a cavity 13, an oil suction port 14 and an oil outlet port 15. The oil suction port 14 is located on one axial side of the housing 1 and communicates with the cavity 13. The oil outlet port 15 is located on the other axial side of the housing 1 and communicates with the cavity 13. The inner wall of the inner gear ring 2 is provided with gear teeth. The inner gear ring 2 is rotatably accommodated in the cavity 13 and abuts against the inner wall of the cavity 13. The gear shaft 3 is at least partially accommodated in the cavity 13, and the portion of the gear shaft 3 accommodated in the cavity 13 penetrates the inner gear ring 2. The axis of the gear shaft 3 does not coincide with the axis of the inner gear ring 2, and the gear shaft 3 is provided with gear teeth corresponding to the inner gear ring 2, and the gear teeth of the gear shaft 3 and the gear teeth of the inner gear ring 2 are engaged with each other. The crescent-shaped body 4 is fixedly arranged between the inner gear ring 2 and the gear shaft 3, and the crescent-shaped body 4 divides the cavity 13 into an oil suction cavity 132 and an oil pressing cavity 131, and the oil suction cavity 132 and the oil pressing cavity 131 are located at two ends of the crescent-shaped body 4, respectively. The inner wall of the housing 1 is provided with an oil introduction channel 16, which communicates with the oil pressing cavity 131. Since the inner wall of the housing 1 is also the inner wall of the cavity 13, the oil introduction channel 16 can introduce the high-pressure medium in the oil pressing cavity 131 to the inner wall of the housing 1. The medium introduced by the oil introduction channel 16 acts on the outer contour of the inner gear ring 2 and applies an outward pushing force to the inner gear ring 2, which offsets a part of the inward pushing force applied to the inner gear ring 2 by the high-pressure medium in the oil pressing cavity 131, thereby reducing the amount of deflection of the inner gear ring 2 towards the housing 1 when rotating at high speed, and further reducing the noise generated by the inner gear ring 2 when rotating at high speed.

[0069] It should be noted that the present application provides a preferred embodiment in the specification and drawings thereof, but the present application can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not additional limitations on the content of the present application, and the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. Furthermore, each of the above technical features continues to be combined, forming various embodiments not listed above, which are considered to be within the scope of the present application. Furthermore, those skilled in the art can make improvements or modifications based on the above description, and all these improvements and modifications shall fall within the scope of the appended claims of the present application.

Claims

1. An internal gear pump, characterized in that, include: The shell has a cavity, an oil suction port, and an oil outlet, wherein the oil suction port and the oil outlet are respectively connected to the cavity; An internal gear ring is rotatably housed within the cavity and abuts against the inner wall of the cavity; The gear shaft is at least partially housed within the cavity, and the gear shaft engages eccentrically with the internal gear ring. A crescent-shaped structure is disposed between the internal gear ring and the gear shaft. The crescent-shaped structure divides the cavity into an oil suction chamber and an oil pressure chamber. The oil suction chamber communicates with the oil suction port, and the oil pressure chamber communicates with the oil outlet. The crescent-shaped structure also divides the cavity into a low-pressure region, a high-pressure region, and a pressure-boosting region. The low-pressure region and the high-pressure region are located on opposite sides of the crescent-shaped structure. The radial boundary of the low-pressure region along the internal gear ring is defined by a line connecting the center of the gear shaft to one side of the crescent-shaped structure and a line connecting the center of the gear shaft to the meshing point of the external and internal teeth. The radial boundary of the high-pressure region along the internal gear ring is defined by a line connecting the center of the gear shaft to the other side of the crescent-shaped structure and a line connecting the center of the gear shaft to the meshing point of the external and internal teeth. An oil inlet passage is located in the high-pressure region. The pressure-boosting region is located between the high-pressure region and the low-pressure region. The inner wall of the housing is provided with an oil inlet passage, which is connected to the oil pressure chamber. The oil inlet passage is used to introduce the high-pressure medium in the oil pressure chamber into the space between the inner wall of the housing and the outer wall of the internal gear ring. One end of the oil inlet passage connected to the inner wall of the housing is an oil outlet, which is located near the crescent-shaped body.

2. The internal gear pump according to claim 1, characterized in that, The oil inlet circuit includes a first section, a second section, and a third section; The first segment is connected to the oil pressure chamber, the third segment is connected to the outer wall of the internal gear ring, the second segment is connected to the first segment and the third segment respectively, and the aperture of the second segment is smaller than the aperture of the first segment and the aperture of the third segment respectively.

3. The internal gear pump according to claim 2, characterized in that, The aperture of the second segment is less than or equal to 1 mm, or the cross-sectional area of ​​the second segment is less than or equal to 3.14 square millimeters.

4. The internal gear pump according to claim 1, characterized in that, The oil pressure chamber includes a first chamber and a second chamber, which are located on opposite sides of the axial direction of the internal gear ring. The first chamber is connected to the second chamber, and the second chamber is connected to the oil outlet. The oil inlet passage is connected to the first chamber and / or the second chamber.

5. The internal gear pump according to claim 4, characterized in that, The oil suction chamber includes a third chamber and a fourth chamber that are connected to each other. The third chamber and the fourth chamber are located on opposite sides of the axial direction of the internal gear ring, and the third chamber is connected to the oil suction port.

6. The internal gear pump according to claim 5, characterized in that, The second chamber and the third chamber are located on opposite sides of the axial direction of the internal gear ring.

7. The internal gear pump according to any one of claims 1-6, wherein the internal gear ring is provided with internal teeth, the gear shaft is provided with external teeth that can mesh with the internal teeth, and the number of internal teeth and external teeth is multiple, and the number of internal teeth is greater than the number of external teeth; The crescent-shaped body is disposed between the inner tooth and the outer tooth, and the crescent-shaped body and the outer tooth together form an oil delivery groove.

8. The internal gear pump according to claim 7, characterized in that, The gear shaft includes a shaft portion and a gear portion. The axis of the shaft portion is parallel to the axis of the internal gear ring. The gear portion is arranged circumferentially around the shaft portion and corresponding to the internal gear ring. The external teeth are arranged circumferentially along the gear portion.

9. The internal gear pump according to claim 7, characterized in that, The internal gear pump further includes a first bearing, which is located within the cavity and on one side of the internal gear ring, and is sleeved on the gear shaft; and / or The internal gear pump also includes a second bearing, which is located on the other side of the internal gear ring and is sleeved on the gear shaft.

10. The internal gear pump according to any one of claims 1-6, characterized in that, The inner wall of the cavity is provided with a groove corresponding to the area where the oil pressure chamber is located, and the groove extends along the axial direction of the internal gear ring.

11. The internal gear pump according to claim 10, characterized in that, The oil inlet passage is located close to the crescent-shaped body; and / or The groove is positioned away from the crescent shape.

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