Internal gear pump

Abstract

The utility model discloses an internal gear pump, and aims to provide an internal gear pump which can effectively solve the problems of abnormal sound and increased noise caused by instantaneous impact of oil liquid in an oil pressing cavity on a tooth groove. The inner rotor and the outer rotor are meshed with each other, the oil suction cavity and the oil pressing cavity are arranged in an inner cavity of the pump body, the inner rotor and the outer rotor are provided with arc-shaped oil seal plates, and each arc-shaped oil seal plate comprises an arc-shaped inner oil seal face matched with the inner rotor and an arc-shaped outer oil seal face matched with the outer rotor. At least one of the arc-shaped inner oil sealing face and the arc-shaped outer oil sealing face is provided with a preloading groove, the preloading groove is close to the oil pressing cavity, and one end of the preloading groove is communicated with the oil pressing cavity.

Description

Technical Field

[0001] The utility model relates to the field of oil pumps, in particular to an internal meshing gear pump. Background Art

[0002] The construction machinery industry is currently in a period of rapid development and adjustment. The oil pump is a key component commonly used in construction machinery, and the internal gear pump is a type of oil pump. An internal gear pump generally comprises a pump body, a pump cover, a drive shaft, meshing inner and outer rotors, and an oil suction chamber and oil pressure chamber within the pump body's inner cavity. The inner and outer rotors are equipped with arc-shaped oil seal plates. During operation, the power source drives the inner and outer rotors to mesh and rotate via the drive shaft. At this point, the meshing gear teeth in the oil suction chamber gradually disengage, increasing the sealed volume and forming a partial vacuum. Under the influence of atmospheric pressure, the oil enters the oil suction chamber through the oil suction pipe. The gear teeth mesh successively, and as the gear pair rotates, the oil is drawn into the oil pressure chamber. Simultaneously, the gap between the teeth gradually decreases as the gear pair rotates, increasing the oil pressure, allowing the oil carried from the oil suction chamber to the oil pressure chamber to be discharged from the pump through the oil outlet. During this process, at the moment when the tooth groove leaves the arc-shaped oil seal plate and connects with the oil pressure chamber, the oil in the oil pressure chamber instantly impacts the tooth groove, and the oil pressure in the tooth groove instantly increases, thereby generating a large oil pressure impact on the meshing inner rotor and outer rotor, generating abnormal noise and increasing noise. Utility Model Content

[0003] The purpose of the utility model is to provide an internal gear pump which can effectively improve the problem of abnormal sound and increased noise caused by the instantaneous impact of oil in the oil pressure chamber on the tooth groove.

[0004] The technical solution of the utility model is:

[0005] An internal meshing gear pump includes a pump body, an inner rotor and an outer rotor that mesh with each other, and an oil suction chamber and an oil pressure chamber arranged in the inner cavity of the pump body. The inner rotor and the outer rotor are provided with an arc-shaped oil seal plate, and the arc-shaped oil seal plate includes an arc-shaped inner oil cover that cooperates with the inner rotor and an arc-shaped outer oil cover that cooperates with the outer rotor. At least one surface of the arc-shaped inner oil cover and the arc-shaped outer oil cover is provided with a preload groove, the preload groove is close to the oil pressure chamber, and one end of the preload groove is connected to the oil pressure chamber. Since a preload groove is provided on at least one surface of the arc-shaped inner oil seal plate and the arc-shaped outer oil seal plate, in the process of the tooth top of the inner rotor or the outer rotor passing through the preload groove, the oil pressure in the oil pressure chamber will gradually be injected into the tooth groove through the preload groove (the oil passage cross-section of the preload groove is smaller), effectively reducing the pressure difference between the oil pressure in the tooth groove close to the oil pressure chamber and the oil pressure in the oil pressure chamber. In this way, at the moment when the tooth groove leaves the arc-shaped oil seal plate and is connected to the oil pressure chamber, the oil pressure shock can be effectively reduced, the abnormal noise of the oil pump can be reduced or even eliminated, the noise can be reduced, and the oil pressure output pulsation can be stabilized; thereby effectively improving the problem of abnormal noise and increased noise caused by the instantaneous impact of the oil in the oil pressure chamber on the tooth groove.

[0006] Preferably, the depth of the preload groove gradually increases in the direction of rotation of the inner rotor. Thus, as the tooth tops of the inner or outer rotor pass through the preload groove, the oil flow cross-section of the preload groove gradually increases accordingly. This allows, on the one hand, the oil pressure in the pressure oil chamber to gradually inject a certain amount of pressure into the tooth groove through the preload groove with a smaller oil flow cross-section at the beginning of the tooth tops of the inner or outer rotor passing through the preload groove (the preload groove has a smaller groove depth and a correspondingly smaller oil flow cross-section), thus avoiding excessive pressure being injected into the tooth groove at the beginning, which would cause abnormal noise and increase noise. On the other hand, the pressure injected into the tooth groove through the preload groove in the pressure oil chamber can be gradually increased, further reducing the pressure difference between the oil pressure in the tooth groove and the oil pressure chamber, thereby further stabilizing the oil pressure output pulsation, reducing or even eliminating abnormal noise from the oil pump, and reducing noise.

[0007] Preferably, the bottom surface of the preload groove is an arcuate surface, and the end of the bottom surface of the preload groove away from the oil pressure chamber is connected to the arcuate inner oil seal or arcuate outer oil seal where the preload groove is located. In this way, when the tooth tips of the inner rotor or outer rotor initially pass through the preload groove, the oil pressure in the oil pressure chamber is smoothly and continuously input into the tooth slot through the preload groove, avoiding sudden and sudden changes in oil pressure entering the tooth slot, thereby further reducing abnormal sounds and noise caused by the tooth tips of the inner rotor or outer rotor initially passing through the preload groove.

[0008] Preferably, the width of the preload groove remains unchanged or gradually increases in the rotation direction of the inner rotor.

[0009] Preferably, the arcuate inner oil seal plate is provided with the preload grooves, and the arcuate inner oil seal plate has a plurality of preload grooves, which are sequentially distributed along the axial direction of the arcuate oil seal plate. Thus, during the design and manufacturing process, different numbers of preload grooves can be directly selected to accommodate the needs of different models of internal gear pumps, facilitating design and manufacturing.

[0010] Preferably, the lengths of the multiple preload grooves on the arc-shaped inner oil cover decrease in sequence. Thus, as the tooth tips of the inner or outer rotor pass through the preload grooves, the oil flow cross-section of the preload grooves gradually increases. This allows, on the one hand, the oil pressure in the pressure oil chamber to gradually inject a certain amount of pressure into the tooth grooves through the preload grooves with smaller oil flow cross-sections at the beginning of the tooth tips of the inner or outer rotor passing through the preload grooves (the preload grooves have a smaller groove depth and correspondingly smaller oil flow cross-section), thus avoiding excessive pressure being injected into the tooth grooves at the beginning, which would cause abnormal noise and increase noise. On the other hand, the pressure injected into the tooth grooves through the preload grooves in the pressure oil chamber can be gradually increased, further reducing the pressure difference between the oil pressure in the tooth grooves and the oil pressure chamber, thereby further stabilizing the oil pressure output pulsation, reducing or even eliminating abnormal noise from the oil pump, and reducing noise.

[0011] Preferably, the arcuate outer oil seal plate is provided with the preload grooves, and the arcuate outer oil seal plate has a plurality of preload grooves, which are sequentially distributed along the axial direction of the arcuate oil seal plate. Thus, during the design and manufacturing process, different numbers of preload grooves can be directly selected to accommodate the needs of different models of internal gear pumps, facilitating design and manufacturing.

[0012] Preferably, the lengths of the multiple preload grooves on the arcuate outer oil cover decrease in sequence. Thus, as the tooth tips of the inner or outer rotor pass through the preload grooves, the oil flow cross-section of the preload grooves gradually increases. This allows, on the one hand, the oil pressure in the pressure oil chamber to gradually inject a certain amount of pressure into the tooth slots through the preload grooves with smaller oil flow cross-sections at the beginning of the tooth tips of the inner or outer rotor passing through the preload grooves (the preload grooves have a smaller groove depth and correspondingly smaller oil flow cross-section), thus avoiding excessive pressure being injected into the tooth slots at the beginning, which would cause abnormal noise and increase noise. On the other hand, the pressure injected into the tooth slots through the preload grooves can be gradually increased, further reducing the pressure difference between the oil pressure near the tooth slots and the oil pressure chamber, thereby further stabilizing the oil pressure output pulsation, reducing or even eliminating abnormal noise from the oil pump, and reducing noise.

[0013] Preferably, the pump cover and the transmission shaft are further included. The pump cover is connected to the pump body by bolts. A sealing ring is provided between the pump cover and the pump body. The pump cover is provided with an oil inlet and an oil outlet, wherein the oil inlet is connected to the oil suction chamber, and the oil outlet is connected to the oil pressure chamber. The transmission shaft is connected to the inner rotor, and one end of the transmission shaft is arranged on the pump body through a deep groove ball bearing, and the other end of the transmission shaft is arranged on the pump cover through a needle roller bearing. This scheme adopts a design combining deep groove ball bearings and needle roller bearings, which can effectively improve the influence of the radial drive of the shaft head rotor on the smooth operation of the rotor pair. It can also ensure the smooth and reliable operation of the rotor pair under complex and harsh working conditions. On the other hand, the other end of the transmission shaft is arranged on the pump cover through a needle roller bearing. The small space occupied by the needle roller bearing itself can be used to reduce the space occupied by the pump cover, which is beneficial to the layout of the oil inlet and oil outlet on the pump cover and improves the compactness of the structure.

[0014] Preferably, both the inner and outer rotors are made of powder metallurgy, and their surfaces are steam-treated to form a wear- and corrosion-resistant film. Powder metallurgy materials can provide higher precision and strength for the inner and outer rotors, extending the service life of the oil pump. Steam-treating the surfaces of both rotors to form a wear- and corrosion-resistant film effectively enhances rust resistance and significantly improves the wear resistance of the rotor pair. This maintains a high surface hardness during long-term use, reducing wear and further extending the service life of the oil pump.

[0015] The beneficial effects of the utility model are: it can effectively reduce the oil pressure shock, reduce or even eliminate the abnormal noise of the oil pump, reduce noise, and make the oil pressure output pulsation stable; thereby effectively improving the problem of abnormal noise and increased noise caused by the instantaneous impact of the oil in the oil pressure chamber on the tooth groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic cross-sectional structure diagram of an internal gear pump of the present invention (a schematic cross-sectional structure diagram along the axial direction of the transmission shaft).

[0017] Figure 2 This is a schematic cross-sectional structure diagram of an internal gear pump of the present invention (a schematic cross-sectional structure diagram along an axial direction perpendicular to the transmission shaft).

[0018] Figure 3 It is a partial enlarged view of the preload groove of an internal gear pump of the present invention.

[0019] Figure 4 It is a partial structural schematic diagram of an implementation method of an arc-shaped oil seal plate of an internal gear pump of the present invention.

[0020] Figure 5 It is a partial structural schematic diagram of another embodiment of the arc-shaped oil seal plate of an internal gear pump of the present invention.

[0021] Figure 6 It is a partial structural schematic diagram of a third embodiment of the arc-shaped oil seal plate of an internal gear pump of the present invention.

[0022] In the picture:

[0023] Pump body 1;

[0024] Pump cover 2;

[0025] Inner rotor 3;

[0026] Outer rotor 4;

[0027] Arc-shaped oil sealing plate 5, arc-shaped inner oil sealing surface 5.1, arc-shaped outer oil sealing surface 5.2, pre-loading groove 5.3;

[0028] Oil suction chamber 6;

[0029] Oil pressure chamber 7;

[0030] Oil inlet 8;

[0031] Oil outlet 9;

[0032] Transmission shaft 10;

[0033] Needle roller bearing 11;

[0034] Deep groove ball bearings 12. DETAILED DESCRIPTION

[0035] Specific embodiment 1, as Figure 1 、 Figure 2 As shown, an internal gear pump includes a pump body 1, a meshing inner rotor 3 and outer rotor 4, and an oil suction chamber 6 and an oil pressure chamber 7 disposed within the inner cavity of the pump body. The inner rotor 3 and the outer rotor 4 are provided with an arcuate oil seal plate 5. The arcuate oil seal plate 5 includes an arcuate inner oil seal surface 5.1 that cooperates with the inner rotor 3 and an arcuate outer oil seal surface 5.2 that cooperates with the outer rotor 4. A preload groove 5.3 is provided on at least one of the surfaces of the arcuate inner oil seal surface 5.1 and the arcuate outer oil seal surface 5.2. The preload groove 5.3 is adjacent to the oil pressure chamber 7, and one end of the preload groove 5.3 is connected to the oil pressure chamber 7. Since the preload groove 5.3 is provided on at least one surface of the arc-shaped inner oil sealing surface 5.1 and the arc-shaped outer oil sealing surface 5.2, as the tooth top of the inner rotor 3 or the outer rotor 4 passes through the preload groove 5.3, the oil pressure in the oil pressure chamber 7 will gradually be injected into the tooth groove through the preload groove 5.3 (the oil passage cross-section of the preload groove 5.3 is relatively small), effectively reducing the pressure difference between the oil pressure in the tooth groove close to the oil pressure chamber 7 and the oil pressure in the oil pressure chamber 7. In this way, at the moment when the tooth groove leaves the arc-shaped oil sealing plate 5 and connects with the oil pressure chamber 7, the oil pressure shock can be effectively reduced, the abnormal noise of the oil pump can be reduced or even eliminated, the noise is reduced, and the oil pressure output pulsation is stabilized; thereby effectively improving the problem of abnormal noise and increased noise caused by the oil in the oil pressure chamber 7 instantaneously impacting the tooth groove. In addition, the preload groove 5.3 is processed on the arc-shaped inner oil cover 5.1 and / or the arc-shaped outer oil cover 5.2, which is not only convenient for processing, but also helps to control the oil pressure in the oil pressure chamber 7 by controlling the groove depth and groove width of the preload groove 5.3 to gradually inject the oil pressure into the tooth grooves of the inner rotor 3 and the outer rotor 4.

[0036] Specific embodiment 2, as Figure 1 、 Figure 2 As shown, an internal meshing gear pump includes a pump body 1, an inner rotor 3 and an outer rotor 4 that mesh with each other, and an oil suction chamber 6 and an oil pressure chamber 7 arranged in the inner cavity of the pump body. In this embodiment, the inner rotor 3 is a gear, and the outer rotor 4 is an inner gear ring. The inner rotor 3 and the outer rotor 4 are provided with an arcuate oil seal plate 5, and the arcuate oil seal plate 5 plays the role of sealing and damping oil. The arcuate oil seal plate 5 includes an arcuate inner oil cover 5.1 that cooperates with the inner rotor 3 and an arcuate outer oil cover 5.2 that cooperates with the outer rotor 4. A preload groove 5.3 is provided on at least one surface of the arcuate inner oil cover 5.1 and the arcuate outer oil cover 5.2. In this embodiment, the preload groove 5.3 on the arcuate inner oil cover 5.1 and / or the arcuate outer oil cover 5.2 is a single groove.

[0037] In one implementation of this embodiment, Figure 2As shown, both the arcuate inner oil seal plate 5.1 and the arcuate outer oil seal plate 5.2 are provided with a preload groove 5.3. Preload groove 5.3 is located near the oil pressure chamber 7, and one end of preload groove 5.3 is connected to the oil pressure chamber 7. As the tooth tips of the inner rotor 3 and outer rotor 4 pass through preload groove 5.3, the oil pressure within the oil pressure chamber 7 is gradually injected into the tooth grooves of the inner rotor 3 and outer rotor 4 through preload groove 5.3 (the preload groove 5.3 has a relatively small oil flow cross-section), effectively reducing the pressure difference between the oil pressure in the tooth grooves near the oil pressure chamber 7 and the oil pressure within the oil pressure chamber 7. This effectively reduces the oil pressure shock at the moment the tooth grooves of the inner rotor 3 and outer rotor 4 leave the arcuate oil seal plate 5 and connect with the oil pressure chamber 7, reducing or even eliminating abnormal noise from the oil pump, reducing noise, and stabilizing the oil pressure output pulsation. This effectively alleviates the abnormal noise and increased noise caused by the oil in the oil pressure chamber 7 momentarily impacting the tooth grooves.

[0038] In another implementation of this embodiment, Figure 3 As shown, the arc-shaped inner oil seal plate 5.1 is provided with a preload groove 5.3. The preload groove 5.3 is close to the oil pressure chamber 7, and one end of the preload groove 5.3 is connected to the oil pressure chamber 7. In this way, when the tooth top of the inner rotor 3 passes through the preload groove 5.3, the oil pressure in the oil pressure chamber 7 will gradually be injected into the tooth groove of the inner rotor 3 through the preload groove 5.3 (the oil flow cross-section of the preload groove 5.3 is relatively small), effectively reducing the pressure difference between the oil pressure in the tooth groove of the inner rotor 3 close to the oil pressure chamber 7 and the oil pressure in the oil pressure chamber 7. In this way, at the moment when the tooth groove of the inner rotor 3 leaves the arc-shaped oil seal plate 5 and is connected to the oil pressure chamber 7, the oil pressure shock can be effectively reduced, the abnormal noise of the oil pump can be reduced or even eliminated, the noise is reduced, and the oil pressure output pulsation is smooth; thereby effectively improving the abnormal noise and increased noise caused by the oil in the oil pressure chamber 7 instantaneously impacting the tooth groove.

[0039] In the third embodiment of this embodiment, the arcuate outer oil seal plate 5.2 is provided with a preload groove 5.3. The preload groove 5.3 is located near the oil pressure chamber 7, and one end of the preload groove 5.3 is connected to the oil pressure chamber 7. Thus, as the tooth tops of the outer rotor 4 pass through the preload groove 5.3, the oil pressure in the oil pressure chamber 7 is gradually injected into the tooth grooves of the outer rotor 4 through the preload groove 5.3 (the oil flow cross-section of the preload groove 5.3 is relatively small), effectively reducing the pressure difference between the oil pressure in the tooth grooves of the outer rotor 4 near the oil pressure chamber 7 and the oil pressure in the oil pressure chamber 7. This effectively reduces the oil pressure shock at the moment when the tooth grooves of the outer rotor 4 leave the arcuate oil seal plate 5 and connect with the oil pressure chamber 7, reducing or even eliminating abnormal noise from the oil pump, reducing noise, and stabilizing the oil pressure output pulsation. This effectively alleviates the abnormal noise and increased noise caused by the oil in the oil pressure chamber 7 instantaneously impacting the tooth grooves.

[0040] In addition, the preload groove 5.3 is processed on the arc-shaped inner oil cover 5.1 and / or the arc-shaped outer oil cover 5.2, which is not only convenient for processing, but also helps to control the oil pressure in the oil pressure chamber 7 by controlling the groove depth and groove width of the preload groove 5.3 to gradually inject the oil pressure into the tooth grooves of the inner rotor 3 and the outer rotor 4.

[0041] Specifically, such as Figure 1 、 Figure 2 As shown, an internal meshing gear pump also includes a pump cover 2 and a drive shaft 10. The pump cover 2 is connected to the pump body 1 by bolts. The inner cavity of the pump body is open to one side of the pump cover 2, and the pump cover 2 covers the opening on one side of the inner cavity of the pump body. A sealing ring is provided between the pump cover 2 and the pump body 1. An oil inlet 8 and an oil outlet 9 are provided on the pump cover 2, wherein the oil inlet 8 is connected to the oil suction chamber 6, and the oil outlet 9 is connected to the oil pressure chamber 7. The drive shaft 10 is arranged on the pump body 1 and the pump cover 2 through bearings. The drive shaft 10 is connected to the inner rotor 3, for example, the drive shaft 10 and the inner rotor 3 are an integrally formed structure, or the drive shaft 10 passes through the inner rotor 3 and is connected to the inner rotor 3 by bolts. In this embodiment, the drive shaft 10 is connected to the inner rotor 3 by a spline.

[0042] During specific operation, the power source drives the inner rotor 3 and the outer rotor 4 to engage and rotate through the transmission shaft 10. At this time, the meshing gear teeth in the oil suction chamber 6 gradually disengage to increase the sealed volume, forming a local vacuum. Under the action of atmospheric pressure, the oil enters the oil suction chamber 6 through the oil inlet 8; the inner rotor 3 and the outer rotor 4 engage and rotate successively, and as the gear pair rotates, the oil is brought into the oil pressure chamber 7. At the same time, the gap between the teeth gradually shrinks as the gear pair rotates, so that the oil brought from the oil suction chamber 6 to the oil pressure chamber 7 is discharged out of the pump from the oil outlet 9.

[0043] Further, such as Figure 1 As shown, one end of the transmission shaft 10 is arranged on the pump body 1 through a deep groove ball bearing 12, and the other end of the transmission shaft 10 is arranged on the pump cover 2 through a needle roller bearing 11. This solution adopts a design that combines deep groove ball bearings and needle roller bearings, which can effectively improve the influence of the radial drive of the shaft head rotor on the smooth operation of the rotor pair. It can also ensure the smooth and reliable operation of the rotor pair under complex and harsh working conditions. On the other hand, the other end of the transmission shaft 10 is arranged on the pump cover 2 through a needle roller bearing. The characteristic of the needle roller bearing itself that it occupies a small space can be used to reduce the space occupied by the pump cover 2, which is beneficial to the layout of the oil inlet 8 and the oil outlet 9 on the pump cover 2 and improves the compactness of the structure.

[0044] In this embodiment, one end of the transmission shaft 10 is provided with a spline hole for connection, and one end of the transmission shaft 10 is provided with a spline head for connection.

[0045] Furthermore, the inner rotor 3 and the outer rotor 4 are both made of powder metallurgy materials. The inner rotor 3 and the outer rotor 4 made of powder metallurgy materials can have higher precision and higher strength, thereby extending the service life of the oil pump.

[0046] The surfaces of both the inner rotor 3 and the outer rotor 4 are steam-treated to form a wear- and corrosion-resistant film. This treatment effectively improves rust resistance and significantly enhances the wear resistance of the rotor pair. This maintains a high surface hardness during long-term use, reducing wear and further extending the service life of the oil pump.

[0047] Furthermore, the gear pair formed by the inner and outer rotors utilizes a two-tooth-difference cycloidal structure. In this two-tooth-difference cycloidal structure, the outer rotor has two more teeth than the inner rotor. This type of gear pair is compact, small, and lightweight, while operating smoothly, with low noise and high volumetric efficiency. Furthermore, it features smooth oil suction and discharge, minimal pressure pulsation, and a long service life. Of course, it should be noted that the gear pair formed by the inner and outer rotors can also utilize a one-tooth-difference cycloidal structure, a three-tooth-difference cycloidal structure, or a four-tooth-difference cycloidal structure.

[0048] Further, such as Figure 2 、 Figure 3 As shown, the groove depth of the preload groove 5.3 gradually increases in the rotation direction of the inner rotor 3. The rotation direction of the inner rotor 3 of the internal gear pump remains unchanged. In this embodiment, the rotation direction of the inner rotor 3 of the internal gear pump rotates clockwise. In this way, as the tooth tops of the inner rotor 3 or the outer rotor 4 pass through the preload groove 5.3, the oil passage cross-section of the preload groove 5.3 gradually increases accordingly. This allows, on the one hand, the oil pressure in the oil pressure chamber 7 to gradually inject a certain pressure into the tooth groove through the preload groove 5.3 with a smaller oil passage cross-section when the tooth tops of the inner rotor 3 or the outer rotor 4 initially pass through the preload groove 5.3 (the preload groove 5.3 has a smaller groove depth and a correspondingly smaller oil passage cross-section), thereby avoiding excessive pressure being injected into the tooth groove at the beginning, which would cause abnormal noise and increase noise. On the other hand, the pressure in the oil pressure chamber 7 injected into the tooth groove through the preload groove 5.3 can be gradually increased, further reducing the pressure difference between the oil pressure in the tooth groove and the oil pressure chamber 7, thereby further stabilizing the oil pressure output pulsation, reducing or even eliminating abnormal noise of the oil pump, and reducing noise.

[0049] The bottom surface of preload groove 5.3 is an arcuate surface, and the end of the bottom surface of preload groove 5.3 away from oil pressure chamber 7 is connected to the arcuate inner oil cover 5.1 or arcuate outer oil cover 5.2 where preload groove 5.3 is located. Thus, when the tooth tips of inner rotor 3 or outer rotor 4 initially pass through preload groove 5.3, the oil pressure within oil pressure chamber 7 is smoothly and continuously input into the tooth slots through preload groove 5.3, avoiding sudden and sudden changes in oil pressure. This further reduces any abnormal sounds and noise caused by the tooth tips of inner rotor 3 or outer rotor 4 initially passing through preload groove 5.3.

[0050] In one implementation of this embodiment, Figure 4 As shown, the groove width of the preload groove 5 . 3 remains constant in the rotation direction of the inner rotor 3 .

[0051] In another implementation of this embodiment, Figure 5 As shown, the width of preload groove 5.3 gradually increases in the rotational direction of inner rotor 3. This allows the pressure in oil pressure chamber 7, which is injected into the tooth slots through preload groove 5.3, to be gradually increased as the tooth tips of inner rotor 3 or outer rotor 4 pass through preload groove 5.3. This further reduces the pressure difference between the oil pressure in the tooth slots and that in oil pressure chamber 7, thereby further stabilizing oil pressure output pulsation, reducing or even eliminating abnormal oil pump noise, and minimizing noise.

[0052] Specific embodiment 3: The rest of the structure of this embodiment refers to specific embodiment 1 or specific embodiment 2, the difference is that:

[0053] like Figure 6 As shown, the arcuate inner oil seal plate 5.1 is provided with the preload groove 5.3. Multiple preload grooves 5.3 are provided on the arcuate inner oil seal plate 5.1, and the preload grooves 5.3 are sequentially distributed along the axial direction of the arcuate oil seal plate 5. This allows for convenient design and production by directly selecting a different number of preload grooves 5.3 to accommodate different models of internal gear pumps.

[0054] Furthermore, the lengths of the multiple preload grooves 5.3 on the arcuate inner oil cover 5.1 decrease in sequence. The length of the preload grooves 5.3 refers to their length in the direction of rotation of the inner rotor 3. As the tooth tips of the inner rotor 3 pass through the preload grooves 5.3, the oil flow cross-section of the preload grooves 5.3 gradually increases. This allows the oil pressure in the pressure oil chamber 7 to gradually flow into the tooth grooves through the preload grooves 5.3 (with their smaller groove depth and correspondingly smaller oil flow cross-section) at the beginning of the tooth tips' passage (preload grooves 5.3 have a smaller groove depth and correspondingly smaller oil flow cross-section). This prevents excessive pressure from being injected initially, which could cause abnormal noise and increase the noise level. Furthermore, this allows the pressure in the pressure oil chamber 7 to gradually increase as it flows into the tooth grooves through the preload grooves 5.3, further reducing the pressure differential between the tooth grooves and the pressure oil chamber 7. This further stabilizes oil pressure output pulsation, reduces or even eliminates abnormal noise from the oil pump, and reduces noise.

[0055] Specific embodiment 4: The rest of the structure of this embodiment refers to specific embodiment 1 or specific embodiment 2, the difference is that:

[0056] The arcuate outer oil seal plate 5.2 is provided with the aforementioned preload grooves 5.3. There are multiple preload grooves 5.3 on the arcuate outer oil seal plate 5.2, and the multiple preload grooves 5.3 on the arcuate outer oil seal plate 5.2 are sequentially distributed along the axial direction of the arcuate oil seal plate 5. This allows for convenient design and manufacturing by directly selecting a different number of preload grooves 5.3 to accommodate different models of internal gear pumps.

[0057] Furthermore, the lengths of the multiple preload grooves 5.3 on the arcuate outer oil cover 5.2 decrease in sequence. The length of the preload grooves 5.3 refers to their length in the direction of rotation of the inner rotor 3. As the tooth tips of the outer rotor 4 pass through the preload grooves 5.3, the oil flow cross-section of the preload grooves 5.3 gradually increases. This allows the oil pressure within the pressure oil chamber 7 to gradually be injected into the tooth grooves through the preload grooves 5.3 (which have a smaller groove depth and a correspondingly smaller oil flow cross-section) at the beginning of the tooth tips' passage (preload grooves 5.3 have a smaller groove depth and a correspondingly smaller oil flow cross-section), thus preventing excessive pressure from being injected initially, which could cause abnormal noise and increase the noise level. Furthermore, this allows the pressure within the pressure oil chamber 7 to gradually increase as it is injected into the tooth grooves through the preload grooves 5.3, further reducing the pressure differential between the tooth grooves and the pressure oil chamber 7. This further stabilizes oil pressure output pulsation, minimizing or even eliminating abnormal noise from the oil pump and reducing noise.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation of the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An internal gear pump comprising a pump body, an inner rotor and an outer rotor meshing with each other, and an oil suction chamber and an oil pressure chamber provided in the inner cavity of the pump body, wherein the inner rotor and the outer rotor are provided with an arc-shaped oil seal plate, wherein: The arc-shaped oil seal plate includes an arc-shaped inner oil seal surface that cooperates with the inner rotor and an arc-shaped outer oil seal surface that cooperates with the outer rotor. A preload groove is provided on at least one surface of the arc-shaped inner oil seal surface and the arc-shaped outer oil seal surface. The preload groove is close to the oil pressure chamber, and one end of the preload groove is connected to the oil pressure chamber.

2. An internal gear pump according to claim 1, characterized in that: The groove depth of the preload groove gradually increases in the rotation direction of the inner rotor.

3. An internal gear pump according to claim 1, characterized in that: The bottom surface of the preloading groove is an arc surface, and one end of the bottom surface of the preloading groove away from the oil pressure chamber is connected to the arc-shaped inner oil cover or the arc-shaped outer oil cover where the preloading groove is located.

4. An internal gear pump according to claim 1, 2 or 3, characterized in that: The slot width of the preloading slot remains unchanged or gradually increases in the rotation direction of the inner rotor.

5. An internal gear pump according to claim 1, 2 or 3, characterized in that: The arc-shaped inner oil seal surface is provided with the preloading groove, and there are multiple preloading grooves on the arc-shaped inner oil seal surface, and the multiple preloading grooves on the arc-shaped inner oil seal surface are distributed in sequence along the axial direction of the arc-shaped oil seal plate.

6. An internal gear pump according to claim 5, characterized in that: The lengths of the multiple preloading grooves on the arc-shaped inner oil cover decrease sequentially.

7. An internal gear pump according to claim 1, 2 or 3, characterized in that: The arc-shaped outer oil seal surface is provided with the preloading groove. There are multiple preloading grooves on the arc-shaped outer oil seal surface, and the multiple preloading grooves on the arc-shaped outer oil seal surface are distributed in sequence along the axial direction of the arc-shaped oil seal plate.

8. An internal gear pump according to claim 7, characterized in that: The lengths of the multiple preloading grooves on the arc-shaped outer oil cover decrease sequentially.

9. An internal gear pump according to claim 1, 2 or 3, characterized in that: It also includes a pump cover and a drive shaft. The pump cover is connected to the pump body by bolts. A sealing ring is provided between the pump cover and the pump body. An oil inlet and an oil outlet are provided on the pump cover. The oil inlet is connected to the oil suction chamber, and the oil outlet is connected to the oil pressure chamber. The drive shaft is connected to the inner rotor. One end of the drive shaft is set on the pump body through a deep groove ball bearing, and the other end of the drive shaft is set on the pump cover through a needle roller bearing.

10. An internal gear pump according to claim 1, 2 or 3, characterized in that: The inner rotor and the outer rotor are both made of powder metallurgy materials, and the surfaces of the inner rotor and the outer rotor are both steam-treated to form a wear- and corrosion-resistant film.

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