Cycloid pump

Abstract

The utility model discloses a cycloid pump which comprises a pump main body, wherein the pump main body is provided with a containing cavity, a liquid inlet and a liquid outlet; the liquid inlet and the liquid outlet are communicated with the containing cavity; the inner rotor is installed in the containing cavity, the outer side face of the inner rotor is provided with a plurality of inner rotating teeth extending outwards, and an inner tooth groove is formed between every two adjacent inner rotating teeth. The outer rotor surrounds to form a rotating space, the inner side face of the outer rotor is provided with a plurality of outer rotating teeth extending towards the rotating space, and an outer tooth groove is formed between every two adjacent outer rotating teeth. The outer rotor is rotatably installed in the containing cavity, the inner rotor is rotatably installed in the rotating space and is eccentrically arranged with the outer rotor, the number of the outer rotating teeth is larger than that of the inner rotating teeth, and when the outer rotor is meshed with the inner rotor, a liquid containing cavity is formed between the end, entering the outer tooth groove, of each inner rotating tooth and the side wall of the outer tooth groove. When the inner gear and the outer gear of the cycloid pump are meshed, the liquid containing cavity can be formed between the inner rotating teeth and the side wall of the outer tooth groove, excessive compression of liquid can be reduced, heat generated when the cycloid pump works can be reduced, and meanwhile noise is lowered.

Description

Technical Field

[0001] This utility model relates to the field of fluid transportation, and more specifically to a cycloidal pump. Background Technology

[0002] A cycloidal pump is a positive displacement rotor pump, named for the cycloidal tooth profile of its inner and outer rotors. It achieves the intake and discharge of liquid through the meshing motion of the rotors. It features a compact structure, stable operation, and low noise, and is widely used in hydraulic systems, lubrication systems, and industrial equipment.

[0003] The structure of a cycloidal pump mainly consists of an inner rotor and an outer rotor. During operation, the inner rotor drives the outer rotor to rotate and forms a dynamic meshing point. The meshing point divides the pump chamber into multiple independent chambers. As the rotor rotates, the volume of the chamber changes periodically. When the volume of the chamber increases, a partial vacuum is formed, and liquid is drawn in through the inlet. When the volume of the chamber decreases, the liquid is compressed and discharged through the outlet. The continuous rotation of the rotor causes the liquid to enter and exit alternately, achieving stable liquid delivery.

[0004] In the current structure, when the inner and outer rotors mesh to reduce the chamber volume and compress the liquid, a large amount of heat is released, causing the cycloidal pump to overheat severely during operation, which affects the service life and performance stability of the cycloidal pump. Utility Model Content

[0005] To address the aforementioned technical problems, the purpose of this utility model is to provide a cycloidal pump in which a liquid-containing cavity is formed between the inner and outer gears when the inner gear meshes with the outer gear groove. This reduces the excessive compression of the liquid, helps to reduce the heat generated during operation of the cycloidal pump, and also reduces noise.

[0006] To achieve the above objectives, the present invention aims to provide a cycloidal pump, comprising:

[0007] A pump body, the pump body having a receiving cavity, an inlet and an outlet communicating with the receiving cavity;

[0008] An inner rotor is installed in the accommodating cavity. The outer surface of the inner rotor has a plurality of outwardly extending inner rotating teeth, and there are inner tooth grooves between adjacent inner rotating teeth.

[0009] An outer rotor surrounds a rotation space, and the inner surface of the outer rotor has a plurality of outer rotating teeth extending into the rotation space, with an outer tooth groove between adjacent outer rotating teeth.

[0010] The outer rotor is rotatably mounted in the accommodating cavity, and the inner rotor is rotatably mounted in the rotation space and eccentrically positioned with respect to the outer rotor. The number of outer rotating teeth is greater than the number of inner rotating teeth. When the outer rotor and the inner rotor mesh, a liquid-containing cavity is formed between the end of the inner rotating tooth that enters the outer tooth groove and the side wall of the outer tooth groove.

[0011] In some embodiments, the bottom of the outer tooth groove of the outer rotor has an expansion groove communicating with the outer tooth groove, and the expansion groove forms the liquid cavity when the inner rotor and the outer rotor are engaged.

[0012] In some embodiments, the outer tooth groove has a first opening adjacent to the inner rotor and communicating with the rotation space, and a second opening away from the inner rotor and communicating with the expansion groove, wherein the width of the second opening is smaller than the width of the first opening, and the width of the expansion groove is smaller than the width of the second opening.

[0013] In some embodiments, the opening width of the expansion groove at the end closer to the inner rotor is greater than the opening width at the end farther from the inner rotor.

[0014] In some embodiments, the outer tooth groove has a first opening adjacent to the inner rotor and communicating with the rotation space, and a second opening away from the inner rotor and communicating with the expansion groove, wherein the width of the second opening is smaller than the width of the first opening, and the width of the expansion groove is larger than the width of the second opening.

[0015] In some embodiments, the outer rotor has a high end portion adjacent to the liquid outlet and a low end portion away from the liquid outlet, and the expansion groove extends from the high end portion to the low end portion.

[0016] In some embodiments, the width of the expansion groove gradually decreases along the direction from the lower end of the outer rotor to the upper end.

[0017] Alternatively, the bottom of the inner tooth groove of the inner rotor has a second expansion groove communicating with the inner tooth groove.

[0018] In some embodiments, the pump body includes a bottom shell, a top shell, and a drive shaft. The top shell is mounted on top of the bottom shell, and the bottom shell surrounds to form the receiving cavity. The top shell surrounds to form the inlet and the outlet. The drive shaft has a first end extending into the receiving cavity and a second end extending out of the top shell. The inner rotor is rotatably mounted on the first end. The pump body includes a first bearing and a second bearing. The first bearing is mounted at the connection between the first end and the bottom shell, and the second bearing is mounted at the connection between the drive shaft and the top shell. The second bearing is a ball bearing.

[0019] In some embodiments, the top shell includes a first top shell and a second top shell disposed adjacent to each other. The first top shell is disposed above the bottom shell. The first top shell has an inlet groove and an outlet groove that are respectively connected to the accommodating cavity. The first top shell also includes a partition located between the inlet groove and the outlet groove. The partition has a shaft hole at the middle position.

[0020] The second top shell is located on one side of the first top shell. The second top shell has a liquid inlet channel and a liquid outlet channel that are separated from each other. The liquid inlet channel connects the liquid inlet tank and the liquid inlet, and the liquid outlet channel connects the liquid outlet tank and the liquid outlet.

[0021] According to another aspect of this application, a cycloidal pump is further provided, comprising:

[0022] A pump body, the pump body having a receiving cavity, an inlet and an outlet communicating with the receiving cavity;

[0023] An inner rotor is installed in the accommodating cavity. The outer surface of the inner rotor has a plurality of outwardly extending inner rotating teeth, and there are inner tooth grooves between adjacent inner rotating teeth.

[0024] An outer rotor surrounds a rotation space, and the inner surface of the outer rotor has a plurality of outer rotating teeth extending into the rotation space, with an outer tooth groove between adjacent outer rotating teeth.

[0025] The outer rotor is rotatably mounted in the accommodating cavity, and the inner rotor is rotatably mounted in the rotation space and eccentrically positioned with respect to the outer rotor. The number of outer rotating teeth is greater than the number of inner rotating teeth. When the outer rotor and the inner rotor mesh, the bottom of the inner tooth groove of the inner rotor has a second expansion groove communicating with the inner tooth groove. Attached Figure Description

[0026] The preferred embodiments will be described below in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages and implementation methods of this utility model.

[0027] Figure 1 This is a first-view perspective three-dimensional structural schematic diagram of the cycloidal pump according to a preferred embodiment of the present invention;

[0028] Figure 2 This is a two-dimensional structural schematic diagram of the cycloidal pump according to a preferred embodiment of the present invention from a second perspective.

[0029] Figure 3 This is an exploded structural diagram of a cycloidal pump according to a preferred embodiment of the present invention;

[0030] Figure 4 This is a top view of the cycloidal pump of a preferred embodiment of the present invention after the inner and outer rotors are assembled.

[0031] Figure 5 This is a top view of a modified embodiment of the cycloidal pump of the preferred embodiment of the present invention, showing the inner and outer rotors after assembly.

[0032] Figure 6 This is a three-dimensional structural diagram of the top shell of the cycloidal pump according to a preferred embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the disassembled structure of the bottom shell, inner rotor, and outer rotor of the cycloidal pump according to a preferred embodiment of this utility model.

[0034] Figure 8 This is a top view of a modified embodiment of the cycloidal pump after the inner and outer rotors are assembled, which is a preferred embodiment of the present invention.

[0035] Attached icon number

[0036] Cycloidal pump 100, pump body 10, accommodating cavity 11, inlet 111, outlet 112, accommodating chamber 12, bottom shell 131, top shell 132, first top shell 1321, inlet groove 13211, outlet groove 13212, partition 13213, shaft hole 13210, second top shell 1322, inlet channel 13221, outlet channel 13222, drive shaft 133, first end 1331, second end 1332, first bearing 141, and the second end 1332. Two bearings 142, oil seal 1425, inner bushing 1421, outer bushing 1422, ball bearing 1423, fixing plate 1424, bearing groove 1311, third top shell 1323, fixing part 13231, inner rotor 20, inner rotating tooth 21, inner tooth groove 22, second expansion groove 23, outer rotor 30, rotation space 31, outer rotating tooth 32, outer tooth groove 33, first opening 331, second opening 332, expansion groove 34, high end part 351, low end part 352. Detailed Implementation

[0037] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the specific implementation methods of this utility model will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0038] To keep the drawings concise, each figure only schematically shows the parts relevant to the utility model, and these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of the components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0039] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0040] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0041] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0042] Reference manual attached Figures 1 to 8 This application provides a cycloidal pump 100, which includes a pump body 10, an inner rotor 20 and an outer rotor 30.

[0043] The pump body 10 has a receiving cavity 11, an inlet 111 communicating with the receiving cavity 11, and an outlet 112. The inner rotor 20 is installed in the receiving cavity 11, and the outer surface of the inner rotor 20 has a plurality of outwardly extending inner rotating teeth 21, with an inner tooth groove 22 between adjacent inner rotating teeth 21. The outer rotor 30 surrounds and forms a rotation space 31, and the inner surface of the outer rotor 30 has a plurality of outer rotating teeth 32 extending into the rotation space 31, with an outer tooth groove 33 between adjacent outer rotating teeth 32.

[0044] The outer rotor 30 is rotatably mounted in the accommodating cavity 11, and the inner rotor 20 is rotatably mounted in the rotating space 31 and eccentrically positioned with respect to the outer rotor 30. The number of outer rotating teeth 32 is greater than the number of inner rotating teeth 21. When the outer rotor 30 and the inner rotor 20 mesh, one end of the inner rotating tooth 21 that enters the outer tooth groove 33 forms a liquid-containing cavity 12 between itself and the side wall of the outer tooth groove 33.

[0045] In this application, the inner rotor 20 and the outer rotor 30 are rotatably mounted in the accommodating cavity 11, and the inner rotor 20 is rotatably mounted within the rotational space 31 formed around the outer rotor 30. When the inner rotor 20 rotates, it can drive the outer rotor 30 to rotate. The number of outer rotating teeth 32 of the outer rotor 30 is greater than the number of inner rotating teeth 21 of the inner rotor 20. When the inner rotor 20 rotates relative to the outer rotor 30, the inner rotor 20 and the outer rotor 30 form a dynamic meshing. During the movement of some inner rotating teeth 21 into the outer tooth groove 33, some inner rotating teeth 21 move away from the outer tooth groove 33. During the movement of the inner rotating teeth 21 into the outer tooth groove 33, the liquid in the outer tooth groove 33 is compressed, increasing the liquid pressure, causing the liquid to be discharged through the liquid outlet 112. During the movement of the inner rotating teeth 21 away from the outer tooth groove 33, a partial vacuum is formed in the outer tooth groove 33, drawing in external liquid through the liquid inlet 111. The continuous rotation of the inner rotor 20 and the outer rotor 30 allows for alternating liquid entry and exit, thereby achieving stable liquid delivery. Preferably, the inner rotor 20 has six inner rotating teeth 21, and the outer rotor 30 has seven outer rotating teeth 32. It is understood that in other embodiments, the number of inner rotating teeth 21 and outer rotating teeth 32 can be implemented as other values, and the specific number of inner rotating teeth 21 and outer rotating teeth 32 should not constitute a limitation of this application.

[0046] In this application, when the inner rotating tooth 21 of the inner rotor 20 moves into the outer tooth groove 33 of the outer rotor 30, a liquid-containing cavity 12 is formed between the inner rotating tooth 21 and the outer tooth groove 33. The liquid-containing cavity 12 can accommodate part of the liquid entering the outer tooth groove 33, reducing the volume change of the liquid entering the outer tooth groove 33, thereby reducing the generated heat. It is worth mentioning that by setting the liquid-containing cavity 12 to reduce the excessive compression of the liquid, it can also reduce the noise generated by squeezing the liquid, thus achieving the effect of noise reduction. It should also be noted that when the inner rotating tooth 21 has fully moved into the outer tooth groove 33, the action of squeezing and discharging the liquid (spitting out the liquid) has been completed, and there is no need to perform the action of compressing the liquid again. Therefore, in this application, when the inner rotor 20 and the outer rotor 30 mesh, the liquid-containing cavity 12 is formed between the inner rotating tooth 21 and the outer tooth groove 33, which will not have a significant impact on the liquid discharge.

[0047] refer to Figure 4 and Figure 5Specifically, the bottom of the outer tooth groove 33 of the outer rotor 30 has an expansion groove 34 that communicates with the outer tooth groove 33. When the inner rotor 20 and the outer rotor 30 are engaged, the expansion groove 34 forms the liquid cavity 12.

[0048] refer to Figure 5 The outer tooth groove 33 has a first opening 331 adjacent to the inner rotor 20 and communicating with the rotation space 31, and a second opening 332 away from the inner rotor 20 and communicating with the expansion groove 34. The width of the second opening 332 is smaller than the width of the first opening 331, and the width of the expansion groove 34 is smaller than the width of the second opening 332.

[0049] Preferably, the opening width of the expansion groove 34 at the end near the inner rotor 20 is greater than the opening width at the end away from the inner rotor 20. Preferably, the cross-section of the inner side of the expansion groove 34 is arc-shaped. It can be understood that the opening width of the expansion groove 34 is smaller than the width of the second opening 332, which can reduce the speed at which the liquid in the outer tooth groove 33 moves into the expansion groove 34, thereby helping to squeeze the liquid in the outer tooth groove 33 to be discharged through the outlet 112.

[0050] refer to Figure 4 The width of the expansion groove 34 is greater than the width of the second opening 332, and the edge portion of the expansion groove 34 extends into the adjacent outer rotating tooth 32, thereby increasing the volume of the expansion groove 34 in the circumferential direction and helping to increase the volume of the expansion groove 34 to accommodate more liquid. It should be noted that in this application, axial direction refers to the direction of the rotation axes of the inner rotor 20 and the outer rotor 30, and circumferential direction refers to the rotation direction of the inner rotor 20 and the outer rotor 30.

[0051] refer to Figure 7 The outer rotor 30 has a high end portion 351 adjacent to the liquid outlet 112 and a low end portion 352 away from the liquid outlet 112. The expansion groove 34 extends from the high end portion 351 to the low end portion 352. The extension of both the external tooth groove 33 and the expansion groove 34 from the high end portion 351 to the low end portion 352 increases the axial volume of the expansion groove 34, thereby increasing its overall volume. It is understood that in some modified embodiments, the expansion groove 34 extends from the high end portion 351 to a midpoint along the axial direction of the outer rotor 30.

[0052] In some embodiments, the width of the expansion groove 34 gradually decreases along the direction from the lower end 352 to the upper end 351 of the outer rotor 30. In other words, along the axial direction, the opening of the expansion groove 34 near the liquid outlet 112 is smaller, and the opening away from the liquid outlet 112 is larger. During operation, because the opening of the expansion groove 34 near the liquid outlet 112 is smaller, the liquid will have greater pressure as it moves from the outer tooth groove 33 and the expansion groove 34 towards the liquid outlet 112, which helps to increase the pressure of the medium discharged through the liquid outlet 112. In some embodiments, along the axial direction, the opening of the expansion groove 34 near the liquid outlet 112 is larger, and the opening away from the liquid outlet 112 is smaller, thereby facilitating the movement of liquid in the outer tooth groove 33 and the expansion groove 34 towards the liquid outlet 112 during operation.

[0053] Reference manual attached Figure 1 , Figure 2 as well as Figure 3 The pump body 10 includes a bottom shell 131, a top shell 132, and a drive shaft 133. The top shell 132 is mounted on top of the bottom shell 131. The bottom shell 131 surrounds and forms the receiving cavity 11. The top shell 132 surrounds and forms the inlet 111 and the outlet 112. The drive shaft 133 has a first end 1331 extending into the receiving cavity 11 and a second end 1332 extending out of the top shell 132. The inner rotor 20 is rotatably mounted on the first end 1331. The pump body 10 includes a first bearing 141 and a second bearing 142. The first bearing 141 is mounted at the connection between the first end 1331 and the bottom shell 131, and the second bearing 142 is mounted at the connection between the drive shaft 133 and the top shell 132. The second bearing 132 is a ball bearing. It is worth noting that ball bearings can withstand larger radial forces, which helps improve the stability of equipment operation and reduce noise generated during operation.

[0054] Preferably, the bottom shell 131 is detachably mounted on the top shell 132, facilitating the installation and replacement of the inner rotor 20 and the outer rotor 30 within the accommodating cavity 11. The drive shaft 133 is rotatably mounted on the top shell 132, with its second end 1332 extending to the outside of the top shell 132. A second bearing 142 is provided at the connection between the drive shaft 133 and the top shell 132. Preferably, the second bearing 142 is a ball bearing capable of withstanding large radial forces, which helps maintain the stability of the drive shaft 133 during rotation and reduces unnecessary friction and noise caused by deflection of the drive shaft 133. Preferably, the first bearing 141 is a self-lubricating bearing. It is understood that the second end 1332 of the drive shaft 133 extends to the outside of the top shell 132 and connects to the drive device. The second bearing 142 will bear a larger axial force relative to the first bearing 141. Configuring the second bearing 142 as a roller bearing and the first bearing 141 as a self-lubricating bearing can help improve the stability of the drive shaft 133 during rotation and also help reduce the overall cost. It is understood that in some embodiments, the first bearing 141 can also be implemented as a ball bearing.

[0055] refer to Figure 3 The second bearing 142 includes an inner bushing 1421, an outer bushing 1422, a plurality of balls 1423, a fixing plate 1424, and an oil seal 1425. The inner bushing 1421 is rotatably fitted onto the drive shaft 133. The outer surface of the inner bushing 1421 has a mounting groove, and the plurality of balls 1423 are rotatably mounted in the mounting groove. The outer bushing 1422 is fitted onto the outside of the inner bushing 1421 to limit the plurality of balls 1423 in the radial direction. The oil seal 1425 is disposed on the side of the balls 1423 away from the outer bushing 1422. The two fixing plates 1424 are respectively located on both sides of the inner bushing 1421 in the axial direction to limit the plurality of balls 1423 in the axial direction.

[0056] refer to Figure 7 The bottom of the bottom shell 131 has a bearing groove 1311 communicating with the accommodating cavity 11. The first bearing 141 is installed in the bearing groove 1311, and the first end 1331 of the drive shaft 133 is installed on the first bearing 141. The bearing groove 1311 of the bottom shell 131 enables the bottom shell 131 to provide support for the first end 1331 of the drive shaft 133, thereby improving the stability of the drive shaft 133 during operation.

[0057] refer to Figure 1 , Figure 2as well as Figure 6 The top shell 132 includes a first top shell 1321 and a second top shell 1322 disposed adjacent to each other. The first top shell 1321 is disposed above the bottom shell 131. The first top shell 1321 has an inlet groove 13211 and an outlet groove 13212 that are respectively connected to the accommodating cavity 11. The first top shell 1321 also includes a partition 13213 located between the inlet groove 13211 and the outlet groove 13212. The partition 13213 has a shaft hole 13210 at the middle position. The drive shaft 133 is rotatably installed in the shaft hole 13210. Correspondingly, the second bearing 142 is installed in the shaft hole 13210 of the partition 13213.

[0058] The second top shell 1322 is located on one side of the first top shell 1321. The second top shell 1322 has a liquid inlet channel 13221 and a liquid outlet channel 13222 that are separated from each other. The liquid inlet channel 13221 connects the liquid inlet tank 13211 and the liquid inlet 111, and the liquid outlet channel 13222 connects the liquid outlet tank 13212 and the liquid outlet 112.

[0059] When the cycloidal pump 100 provided in this application is working, external liquid can enter the inlet channel 13221 through the inlet port 111, enter the inlet tank 13211 through the inlet channel 13221, enter the receiving cavity 11 through the inlet tank 13211, enter the outlet tank 13212 through the receiving cavity 11, enter the outlet channel 13222 through the outlet tank 13212, and be discharged through the outlet port 112.

[0060] refer to Figure 6 The liquid inlet groove 13211 and the liquid outlet groove 13212 extend circumferentially along the shaft hole 13210 by a predetermined length. The liquid inlet groove 13211 and the liquid outlet groove 13212 correspond to a plurality of external toothed grooves 33, thereby facilitating more liquid to enter the external toothed grooves 33 from the liquid inlet groove 13211 or for liquid in the external toothed grooves 33 to exit through the liquid outlet groove 13212.

[0061] refer to Figure 1 The top shell 132 further includes a third top shell 1323 located above the first top shell 1321. The third top shell 1323 has two fixing portions 13231 on both sides for fixed connection with external equipment. The second end 1332 of the drive shaft 133 extends through the third top shell 1323 to the outside of the third top shell 1323. Preferably, each of the two fixing portions 13231 has a fixing groove.

[0062] refer to Figure 8 In some embodiments, when the inner rotor 20 and the outer rotor 30 are engaged, a liquid-containing cavity 12 is formed between the outer rotating tooth 32 and the inner tooth groove 22. That is, the bottom of the inner tooth groove 22 of the inner rotor 20 has a second expansion groove 23 communicating with the inner tooth groove 22. The structure and function of the liquid-containing cavity 12 formed between the outer rotating tooth 32 and the inner tooth groove 22 are the same as the structure and principle of the liquid-containing cavity 12 formed between the inner rotating tooth 21 and the outer tooth groove 33 described above, and will not be repeated here.

[0063] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The advantages of the present invention have been fully and effectively realized. The functions and structural principles of the present invention have been shown and explained in the embodiments, and any modifications or variations may be made to the implementation of the present invention without departing from the stated principles.

Claims

1. A gerotor pump, characterized by, The pump comprises: a pump body having a receiving cavity, an inlet and an outlet; an inner rotor installed in the receiving cavity, the outer side of the inner rotor having a plurality of inner rotor teeth extending outward, and the inner rotor teeth being separated by inner tooth grooves; an outer rotor surrounding a rotating space, the inner side of the outer rotor having a plurality of outer rotor teeth extending toward the rotating space, and the outer rotor teeth being separated by outer tooth grooves; the outer rotor is rotatably installed in the receiving cavity, the inner rotor is rotatably installed in the rotating space and is eccentrically arranged with the outer rotor, the number of the outer rotor teeth is greater than the number of the inner rotor teeth, and when the outer rotor and the inner rotor are engaged, the inner rotor teeth enter the space between one end of the outer tooth groove and the side wall of the outer tooth groove to form a liquid receiving cavity.

2. The gerotor pump of claim 1, wherein The bottom of the outer tooth groove of the outer rotor has an expansion groove in communication with the outer tooth groove, and when the inner rotor and the outer rotor are engaged, the expansion groove forms the liquid receiving cavity.

3. The gerotor pump of claim 2, wherein The outer tooth groove has a first opening adjacent to the inner rotor and in communication with the rotating space, and a second opening away from the inner rotor and in communication with the expansion groove, the width of the second opening is smaller than the width of the first opening, and the width of the expansion groove is smaller than the width of the second opening.

4. The gerotor pump of claim 3, wherein The opening width of one end of the expansion groove close to the inner rotor is greater than the opening width of the end away from the inner rotor.

5. The gerotor pump of claim 2, wherein, The outer tooth groove has a first opening adjacent to the inner rotor and in communication with the rotating space, and a second opening away from the inner rotor and in communication with the expansion groove, the width of the second opening is smaller than the width of the first opening, and the width of the expansion groove is greater than the width of the second opening.

6. The gerotor pump according to any one of claims 2 to 5, characterized in that The outer rotor has a high end portion adjacent to the outlet and a low end portion away from the outlet, and the expansion groove extends from the high end portion to the low end portion.

7. The gerotor pump of claim 6, wherein The width of the expansion groove gradually decreases in the direction from the low end portion to the high end portion of the outer rotor. Alternatively, the bottom of the inner tooth groove of the inner rotor has a second expansion groove in communication with the inner tooth groove.

8. The gerotor pump according to any one of claims 1 to 5, characterized in that The pump body comprises a bottom shell, a top shell and a transmission shaft, the top shell is installed on the top of the bottom shell, the bottom shell surrounds the receiving cavity, the top shell surrounds the inlet and the outlet, the transmission shaft has a first end portion extending into the receiving cavity and a second end portion extending out of the top shell, the inner rotor is rotatably installed on the first end portion, the pump body comprises first and second bearings, the first bearing is installed at the connection between the first end portion and the bottom shell, and the second bearing is installed at the connection between the transmission shaft and the top shell, wherein the second bearing is a ball bearing.

9. The gerotor pump of claim 8, wherein, The top shell comprises a first top shell and a second top shell arranged adjacent to each other, the first top shell is arranged above the bottom shell, the first top shell has an inlet groove and an outlet groove in communication with the receiving cavity respectively, the first top shell further comprises a partition plate between the inlet groove and the outlet groove, and the middle position of the partition plate has an axle hole. The second top shell is located at one side of the first top shell, and has a liquid inlet channel and a liquid outlet channel separated from each other in the second top shell.

10. A gerotor pump characterized by, Comprise: A pump body, the pump body has a containing cavity, a liquid inlet and a liquid outlet which communicate with the containing cavity; An inner rotor, the inner rotor is installed in the containing cavity, and the outer side of the inner rotor has a plurality of inner rotor teeth extending outward, and the inner rotor teeth have inner tooth grooves between adjacent inner rotor teeth; An outer rotor, the outer rotor surrounds a rotating space, and the inner side of the outer rotor has a plurality of outer rotor teeth extending to the rotating space, and the outer rotor teeth have outer tooth grooves between adjacent outer rotor teeth; The outer rotor is rotatably installed in the containing cavity, the inner rotor is rotatably installed in the rotating space and is eccentrically arranged with the outer rotor, the number of the outer rotor teeth is more than the number of the inner rotor teeth, and when the outer rotor and the inner rotor are engaged, the bottom of the inner tooth groove of the inner rotor has a second expansion groove which communicates with the inner tooth groove.

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