Variable gear pump

Abstract

The utility model provides a variable gear pump. The variable gear pump comprises a shell; the gear assembly is arranged in the shell, the gear assembly comprises two gear parts which are meshed with each other, and each gear part comprises a gear; the tooth crest of at least one gear comprises a first tooth crest section and a second tooth crest section, and the first tooth crest section and the second tooth crest section are arranged in the direction of the center line of the corresponding gear. Wherein the overlapping coefficient of the first tooth crest section of one gear and the first tooth crest section of the other gear is larger than 1 when the first tooth crest section of one gear is meshed with the first tooth crest section of the other gear, and the overlapping coefficient of the first tooth crest section of one gear and the second tooth crest section of the other gear is equal to 1 when the first tooth crest section of one gear is meshed with the second tooth crest section of the other gear. The gear pump aims to solve the problem of oil trapping in the working process of a gear pump in the prior art.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of hydraulic pressure, specifically, relates to a variable gear pump. BACKGROUND

[0002] Variable gear pump is a kind of hydraulic transmission liquid variable capacity type machine, it changes the displacement inside gear pump to regulate output flow, it is applicable to the machining needing high precision and high stability.Variable gear pump's characteristics are simple structure, low cost, strong self-suction capacity, strong oil pollution resistance, it is widely used in hydraulic system, it can realize the regulation or automatic control of flow by adjusting mechanism, it is applicable to the hydraulic machinery in medium, low pressure range, it can replace the fixed displacement gear pump in many hydraulic systems.But, the gear pump in prior art has the following defects:

[0003] Gear pump in the working process, due to the overlapping coefficient design of gear is greater than 1, to ensure the continuous oil supply of gear pump, two pairs of gear meshing simultaneously can appear, in this period, part of oil is trapped in the closed oil cavity formed by two pairs of gear, this closed oil cavity is neither communicated with suction chamber, also not communicated with pressure oil chamber, when gear pump runs, the volume of closed oil cavity will first decrease and then increase, when the volume decreases, oil is compressed, the compression of oil can cause pressure to rise, possibly cause oil heating and bearing load increase;When the volume increases, local vacuum is formed, and local vacuum can cause cavitation phenomenon, vibration and noise are generated, and this pressure impact and cavitation phenomenon caused by closed volume change are called oil trapping phenomenon.

[0004] The gear pump in prior art usually has the following several methods to reduce the occurrence of oil trapping phenomenon: 1, use side plate to add unloading groove to avoid structural oil trapping phenomenon;2, by gear face modification and side plate to add unloading groove to achieve this purpose;3, gear adopts double modulus processing;4, gear face processing unloading groove;But, the way of adding unloading groove can increase the friction of end surface, and the direction of jet flow will impact the material of side plate;Double modulus processing needs to adjust the modulus of gear processing;Gear face processing unloading groove is difficult. UTILITY MODEL CONTENTS

[0005] The main purpose of the utility model is to provide a kind of variable gear pump, to solve the problem of oil trapping phenomenon of gear pump in prior art in the working process.

[0006] To achieve the above objectives, according to one aspect of the present invention, a variable gear pump is provided, comprising: a housing; a gear assembly disposed within the housing, the gear assembly including two meshing gear portions, each gear portion including a gear; at least one gear having a tooth tip including a first tooth tip segment and a second tooth tip segment, the first tooth tip segment and the second tooth tip segment being arranged along the centerline direction of the corresponding gear; wherein, the overlap coefficient between the first tooth tip segment of one gear and the first tooth tip segment of another gear when meshing is greater than 1, and the overlap coefficient between the first tooth tip segment of one gear and the second tooth tip segment of another gear when meshing is equal to 1.

[0007] Furthermore, the variable gear pump includes an auxiliary ring assembly, which includes an auxiliary ring disposed on the outer peripheral surface of the second tooth tip section of the gear assembly. The auxiliary ring is connected to the housing and is clearance-fitted with the outer peripheral surface of the second tooth tip section to seal the oil at the corresponding second tooth tip section.

[0008] Furthermore, the housing includes: a bottom housing assembly, in which at least a portion of the gear assembly is disposed, and the bottom housing assembly is provided with an oil drain port and an oil suction port; and a cover plate, which covers the bottom housing assembly to form a sealed cavity for housing the gear assembly.

[0009] Furthermore, the two gear assemblies are: a driving gear assembly, which is disposed in a sealed cavity, including a driving gear and a driving shaft, wherein the driving gear is fixedly sleeved on the driving shaft and the driving shaft is connected to a motor so that the motor drives the driving gear to rotate; and a driven gear assembly, which is disposed in a sealed cavity, including a driven gear and a driven shaft, wherein the driven gear is fixedly sleeved on the driven shaft and meshes with the driving gear.

[0010] Furthermore, the variable gear pump includes two support ring assemblies, wherein each support ring assembly includes a first support ring and a second support ring connected together. The first support rings of both support ring assemblies are sleeved on the drive shaft and located at both ends of the drive gear, and the drive shaft and drive gear are rotatably arranged relative to the first support rings of the two support ring assemblies. The second support rings of both support ring assemblies are sleeved on the driven shaft and located at both ends of the driven gear, and the driven shaft and driven gear are rotatably arranged relative to the second support rings of the two support ring assemblies.

[0011] Furthermore, the second tooth tip section of the driving gear is located at one of the driving gear near the bottom housing assembly and the cover plate, and the second tooth tip section of the driven gear is located at the other of the driven gear near the bottom housing assembly and the cover plate.

[0012] Furthermore, the auxiliary ring assembly includes two auxiliary rings, which are arranged one-to-one with two second tooth tip sections, and each auxiliary ring is also provided with a pressure equalization groove.

[0013] Furthermore, the cover plate is provided with an adjusting oil hole, which is correspondingly arranged with the second support ring located above the driven gear; an oil storage tank is provided on the bottom surface of the bottom shell assembly, one end of the oil storage tank is connected to the bottom of the second support ring located below the driven gear, and the other end of the oil storage tank is connected to the oil drain port; wherein, by injecting control oil into the adjusting oil hole, pressure is applied to the second support ring located above the driven gear, so that the driven gear moves in the axial direction under the pressure difference between the oil storage tank and the adjusting oil hole.

[0014] Furthermore, both the first support ring and the second support ring are circular ring structures, and the thickness of the first support ring is greater than that of the second support ring. The second support ring is movably arranged relative to the first support ring along the axial direction so as to drive the driven gear to move axially under the action of pressure difference.

[0015] Furthermore, the bottom housing assembly also includes two bottom housing connecting shaft holes, which are used to install one end of the drive shaft and the driven shaft, respectively; a part of the oil reservoir is connected to the oil drain port, and the other part of the oil reservoir is arranged around the bottom housing connecting shaft hole corresponding to the driven shaft, so as to transmit the output pressure of the oil drain port to the bottom of the driven gear.

[0016] By applying the technical solution of this utility model, the variable gear pump of this utility model designs the gear tooth tip as a first tooth tip section and a second tooth tip section. The second tooth tip section is formed by cutting off a portion of the gear tooth tip circle, so that the overlap coefficient of the first tooth tip section of one gear with the first tooth tip section of another gear when meshing is greater than 1. The overlap coefficient greater than 1 reduces the vibration and noise of the gear pump during operation, ensuring the smoothness of the gear pump during operation. The overlap coefficient of the second tooth tip section of one gear with the first tooth tip section of another gear when meshing is equal to 1, avoiding the formation of oil trapping zone. Furthermore, the variable gear pump of this utility model automatically adjusts the output flow by changing the meshing state of the gear section, without the need for an external control mechanism, realizing more precise and timely flow control. It effectively solves the problem of oil trapping in the gear pump during operation in the prior art, avoiding pressure fluctuations and efficiency losses caused by oil trapping. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0018] Figure 1 This diagram illustrates the assembly structure of the gear assembly, auxiliary ring assembly, and support ring assembly according to an embodiment of a variable gear pump of the present invention; and

[0019] Figure 2A schematic diagram of the gear assembly installed inside the housing is shown;

[0020] Figure 3 A schematic diagram of the structure in one direction is shown when two gear sets are meshing;

[0021] Figure 4 A schematic diagram of the structure in another direction is shown when two gear sets are meshing;

[0022] Figure 5 A schematic diagram of the internal structure of the bottom shell assembly is shown;

[0023] Figure 6 A schematic diagram of the auxiliary ring assembly is shown.

[0024] Figure 7 A schematic diagram of one embodiment of the support ring assembly is shown;

[0025] Figure 8 A schematic diagram of another embodiment of the support ring assembly is shown;

[0026] Figure 9 A schematic diagram of the cover plate is shown.

[0027] The above figures include the following reference numerals:

[0028] 10. Housing; 20. Gear assembly; 30. Auxiliary ring assembly; 40. Drive gear assembly; 50. Driven gear assembly; 60. Support ring assembly;

[0029] 210. Gear section; 220. Gear; 230. First tooth tip section; 240. Second tooth tip section;

[0030] 310. Auxiliary ring; 320. Clearance opening;

[0031] 311. Equalizing tank;

[0032] 141. Adjust the oil hole;

[0033] 111. Bottom surface of the tank; 112. Oil storage tank; 113. Bottom shell connecting shaft hole; 114. First tank section; 115. Second tank section;

[0034] 110. Bottom shell assembly; 120. Oil drain port; 130. Oil suction port; 140. Cover plate; 150. Sealed cavity;

[0035] 410. Drive gear; 420. Drive shaft;

[0036] 510. Driven gear; 520. Driven shaft;

[0037] 610. First support ring; 620. Second support ring. Detailed Implementation

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] like Figures 1 to 9 As shown, the variable gear pump of this utility model includes: a housing 10; a gear assembly 20, which is disposed inside the housing 10. The gear assembly 20 includes two meshing gear portions 210, each gear portion 210 including a gear 220; at least one gear 220 has a tooth tip including a first tooth tip section 230 and a second tooth tip section 240, which are arranged along the centerline direction of the corresponding gear 220; wherein, the overlap coefficient between the first tooth tip section 230 of one gear 220 and the first tooth tip section 230 of another gear 220 when meshing is greater than 1, and the overlap coefficient between the first tooth tip section 230 of one gear 220 and the second tooth tip section 240 of another gear 220 when meshing is equal to 1.

[0040] Thus, the variable gear pump of this invention designs the tooth tip of gear 220 as a first tooth tip section 230 and a second tooth tip section 240. The second tooth tip section 240 is formed by cutting off a portion of the tooth tip circle of gear 220, so that the overlap coefficient of the first tooth tip section 230 of one gear 220 with the first tooth tip section 230 of another gear 220 when meshing is greater than 1. The overlap coefficient greater than 1 reduces the vibration and noise of the gear pump during operation, ensuring the stability of the gear pump during operation. The overlap coefficient of the second tooth tip section 240 of gear 220 with the first tooth tip section 230 of another gear 220 when meshing is equal to 1, avoiding the formation of oil trapping zone. Furthermore, the variable gear pump of this invention automatically adjusts the output flow by changing the meshing state of gear section 210, without the need for an external control mechanism, achieving more precise and timely flow control. It effectively solves the problem of oil trapping in the gear pump during operation in the prior art, avoiding pressure fluctuations and efficiency losses caused by oil trapping.

[0041] like Figure 6 As shown, the variable gear pump includes an auxiliary ring assembly 30, which includes an auxiliary ring 310 disposed on the outer peripheral surface of the second tooth tip section 240 of the gear assembly 20. The auxiliary ring 310 is connected to the housing 10, and the auxiliary ring 310 is clearance-fitted with the outer peripheral surface of the second tooth tip section 240 to seal the oil at the corresponding second tooth tip section 240. The clearance fit between the auxiliary ring 310 and the outer peripheral surface of the second tooth tip section 240 can form a tight sealing interface, effectively preventing oil leakage at the gap between the outer side of the second tooth tip section 240 and the pump housing 10, and enhancing the sealing performance of adjacent tooth grooves at the second tooth tip section 240 located between them.

[0042] Preferably, the auxiliary ring 310 is a semi-annular structure with an avoidance opening 320.

[0043] like Figure 2 and Figure 9 As shown, the outer casing 10 includes: a bottom casing assembly 110, with at least a portion of the gear assembly 20 disposed within the bottom casing assembly 110, and the bottom casing assembly 110 having an oil drain port 120 and an oil suction port 130; and a cover plate 140, which covers the bottom casing assembly 110 to form a sealed cavity 150 for housing the gear assembly 20. The design of the sealed cavity 150 between the bottom casing assembly 110 and the cover plate 140 ensures the sealing performance of the gear assembly 20 during operation, effectively reducing oil leakage and improving the efficiency and reliability of the gear pump. Furthermore, the oil drain port 120 and the oil suction port 130 on the bottom casing assembly 110 are located on opposite sides of the gear assembly 20, which facilitates uniform oil intake and discharge, optimizes the internal oil circuit design of the gear pump, and enables more effective control of the hydraulic system pressure, ensuring the smooth operation of the gear pump.

[0044] like Figure 3 As shown, the two gear assemblies 20 are: a drive gear set 40, disposed within the sealed cavity 150, comprising a drive gear 410 and a drive shaft 420, with the drive gear 410 fixedly mounted on the drive shaft 420, and the drive shaft 420 connected to a motor to drive the drive gear 410 to rotate; and a driven gear set 50, disposed within the sealed cavity 150, comprising a driven gear 510 and a driven shaft 520, with the driven gear 510 fixedly mounted on the driven shaft 520, and meshing with the drive gear 410. The direct connection between the drive gear set 40 and the motor ensures that the motor's driving energy can be directly and efficiently transmitted to the drive gear 410, thereby improving the pump's driving efficiency. Furthermore, the precise meshing of the drive gear 410 and the driven gear 510 ensures the smooth operation of the gear pump and reduces vibration.

[0045] Preferably, the drive gear 410 and the drive shaft 420 are integrally formed.

[0046] Preferably, the driven gear 510 and the driven shaft 520 are integrally formed.

[0047] like Figure 7 and Figure 8As shown, the variable gear pump includes: two support ring assemblies 60, wherein each support ring assembly 60 includes a first support ring 610 and a second support ring 620 connected together. The first support rings 610 of the two support ring assemblies 60 are both sleeved on the drive shaft 420 and are respectively located at both ends of the drive gear 410. The drive shaft 420 and the drive gear 410 are rotatably arranged relative to the first support rings 610 of the two support ring assemblies 60. The second support rings 620 of the two support ring assemblies 60 are both sleeved on the driven shaft 520 and are respectively located at both ends of the driven gear 510. The driven shaft 520 and the driven gear 510 are rotatably arranged relative to the second support rings 620 of the two support ring assemblies 60.

[0048] In one embodiment of this utility model, the support ring assembly 60 is Figure 7 The structure shown.

[0049] In another embodiment of this utility model, the support ring assembly 60 is... Figure 8 The structure shown.

[0050] Specifically, in this utility model, the driving gear 410 and the driven gear 510 in the two gear parts 210 rotate, and the two support ring assemblies 60 are fixedly connected to the two gear parts 210.

[0051] The first support ring 610 and the second support ring 620 are respectively sleeved on the drive shaft 420 and the driven shaft 520. The two first support rings 610 are located at both ends of the drive gear 410, and the two second support rings 620 are located at both ends of the driven gear 510. This provides axial support and positioning for the drive gear 410 and the driven gear 510, ensuring the stability of the drive gear 410 and the driven gear 510 during operation, reducing axial offset and vibration, and improving the service life and operating efficiency of the gear pump.

[0052] like Figure 4 As shown, the second tooth tip section 240 of the driving gear 410 is disposed at one of the driving gear 410 near the bottom housing assembly 110 and the cover plate 140, and the second tooth tip section 240 of the driven gear 510 is disposed at the other of the driven gear 510 near the bottom housing assembly 110 and the cover plate 140.

[0053] Specifically, when the variable gear pump starts working, when the first tooth tip section 230 of the driving gear 410 and the driven gear 510 engages, the corresponding second tooth tip sections 240 of the driving gear 410 and the driven gear 510 do not engage. The oil in the first tooth tip section 230 flows out from the two second tooth tip sections 240 at both ends. When the two second tooth tip sections 240 at both ends engage, the gears have already left the oil trapping zone, thus effectively avoiding the occurrence of oil trapping.

[0054] likeFigure 6 As shown, the auxiliary ring group 30 includes two auxiliary rings 310, which are arranged one-to-one with two second tooth tip sections 240. Each auxiliary ring 310 is also provided with a pressure equalization groove 311. The design of the pressure equalization groove 311 allows the oil in the tooth groove located at the pressure equalization groove 311 to flow to the adjacent tooth groove when the auxiliary ring 310 moves, effectively balancing the local high pressure and low pressure areas generated during gear meshing, reducing pressure pulsation in oil flow, improving the smoothness of pump operation and reducing noise.

[0055] Preferably, the equalizing groove 311 extends circumferentially along the auxiliary ring 310 and is located on the side of the auxiliary ring 310 away from the corresponding first tooth tip segment 230.

[0056] like Figure 9 As shown, the cover plate 140 is provided with an adjusting oil hole 141, which is correspondingly provided with the second support ring 620 located above the driven gear 510; the bottom surface 111 of the bottom shell assembly 110 is provided with an oil storage tank 112, one end of the oil storage tank 112 is connected to the bottom of the second support ring 620 located below the driven gear 510, and the other end of the oil storage tank 112 is connected to the oil drain port 120; wherein, by injecting control oil into the adjusting oil hole 141, pressure is applied to the second support ring 620 located above the driven gear 510, so that the driven gear 510 moves in the axial direction under the pressure difference between the oil storage tank 112 and the adjusting oil hole 141.

[0057] Specifically, by injecting control oil with the calculated target pressure into the adjusting oil hole 141 of the cover plate 140, pressure can be generated on the second support ring 620 located above the driven gear 510. The outlet pressure enters one side of the second support ring 620 located below the driven gear 510 through the oil storage tank 112 provided on the bottom surface 111 of the bottom shell assembly 110. When the outlet pressure is greater than the target pressure, it pushes the driven gear set 50 to move in the axial direction, thereby adjusting the position of the driven gear 510 in the axial direction within the housing 10. This adjusts the tooth width of the meshing area of ​​the driving gear 410 and the driven gear 510, causing the driving gear 410 and the driven gear 510 to idle in the non-meshing area. If the ratio of the tooth width of the driving gear 410 and the driven gear 510 in the idle area to the meshing area changes from 0 to 1 / 2, it indicates that the output oil displacement of the gear pump is reduced by 1 / 3, thereby changing the output oil displacement of the gear pump. When the driven gear 510 is flush with the two end faces of the driven gear 510, the output oil is at its maximum displacement. Since the areas of the second support rings 620 on both sides of the driven gear 510 are different, the pressure at the adjusting oil hole 141 needs to be calculated and applied.

[0058] Preferably, both the first support ring 610 and the second support ring 620 are circular ring structures, and the thickness of the first support ring 610 is greater than the thickness of the second support ring 620. The second support ring 620 is movably arranged relative to the first support ring 610 along the axial direction so as to drive the driven gear 510 to move axially under the action of pressure difference.

[0059] Preferably, the contact surface of one of the first support ring 610 and the second support ring 620 at the connection point is an arc-shaped surface.

[0060] The thickness difference design between the second support ring 620 and the first support ring 610, combined with its axial mobility, allows the pressure difference formed between the adjustment oil hole 141 on the cover plate 140 and the oil reservoir 112 of the bottom shell assembly 110 to act precisely on the second support ring 620 and drive the driven gear 510 to move efficiently along the axial direction, thereby achieving fast and precise variable control.

[0061] Specifically, the bottom housing assembly 110 also includes two bottom housing connecting shaft holes 113, which are used to install one end of the drive shaft 420 and the driven shaft 520, respectively. The bottom housing connecting shaft holes 113 provide a stable base for installing the drive shaft 420 and the driven shaft 520, enhance the support and positioning of the drive shaft 420 and the driven shaft 520, reduce radial displacement, and improve the operating stability and reliability of the pump.

[0062] Specifically, a portion of the oil reservoir 112 is connected to the oil outlet 120, which reduces energy loss during oil flow and improves the working efficiency of the gear pump. At the same time, this design also helps to reduce oil turbulence and noise inside the pump body. Another portion of the oil reservoir 112 is arranged around the bottom housing connecting shaft hole 113 corresponding to the driven shaft 520 to transmit the output pressure of the oil outlet 120 to the bottom of the driven gear 510, ensuring the accuracy and timeliness of pressure transmission and improving the efficiency and response speed of variable control.

[0063] Preferably, the oil storage tank 112 includes a first tank section 114 and a second tank section 115 connected to each other, wherein the oil storage tank 112 that communicates with the oil outlet 120 is the first tank section 114, and the oil storage tank 112 that surrounds the bottom shell connecting shaft hole 113 corresponding to the driven shaft 520 is the second tank section 115.

[0064] Specifically, the cover plate 140 also includes two cover plate connecting shaft holes, which are coaxially arranged with the two bottom shell connecting shaft holes 113 to fix the drive shaft 420 and the driven shaft 520.

[0065] The advantages of this utility model are as follows:

[0066] 1. The gear processing of this utility model is more convenient, requiring only a portion to be machined off.

[0067] 2. By introducing the outlet oil into the bottom of the second support ring 620, automatic variable displacement can be achieved.

[0068] 3. This utility model effectively avoids the phenomenon of oil trapping.

[0069] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:

[0070] The variable gear pump of this utility model includes: a housing 10; a gear assembly 20 disposed within the housing 10, the gear assembly 20 including two meshing gear portions 210, each gear portion 210 including a gear 220; at least one gear 220 has a tooth tip including a first tooth tip section 230 and a second tooth tip section 240, the first tooth tip section 230 and the second tooth tip section 240 being arranged along the centerline direction of the corresponding gear 220; wherein, the overlap coefficient between the first tooth tip section 230 of one gear 220 and the first tooth tip section 230 of another gear 220 when meshing is greater than 1, and the overlap coefficient between the first tooth tip section 230 of one gear 220 and the second tooth tip section 240 of another gear 220 when meshing is equal to 1.

[0071] As can be seen, the variable gear pump of this invention designs the tooth tip of gear 220 as a first tooth tip section 230 and a second tooth tip section 240. The second tooth tip section 240 is formed by cutting off a portion of the tooth tip circle of gear 220, so that the overlap coefficient of the first tooth tip section 230 of one gear 220 with the first tooth tip section 230 of another gear 220 when meshing is greater than 1. The overlap coefficient greater than 1 reduces the vibration and noise of the gear pump during operation and ensures the stability of the gear pump during operation. The overlap coefficient of the second tooth tip section 240 of gear 220 with the first tooth tip section 230 of another gear 220 when meshing is equal to 1, avoiding the formation of oil trapping zone. Moreover, the variable gear pump of this invention automatically adjusts the output flow by changing the meshing state of gear section 210 without the need for external control mechanism, realizing more precise and timely flow control, effectively solving the problem of oil trapping in the gear pump during operation in the prior art, and avoiding pressure fluctuations and efficiency losses caused by oil trapping.

[0072] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0073] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0074] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0075] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0076] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0077] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A variable gear pump, characterized in that, include: Outer shell (10); A gear assembly (20) is disposed within the housing (10). The gear assembly (20) includes two meshing gear portions (210), each of which includes a gear (220). At least one of the gears (220) has a tooth tip including a first tooth tip section (230) and a second tooth tip section (240), the first tooth tip section (230) and the second tooth tip section (240) being arranged along the centerline direction of the respective gear (220). Wherein, the overlap coefficient between the first tooth tip section (230) of one gear (220) and the first tooth tip section (230) of another gear (220) when meshing is greater than 1, and the overlap coefficient between the first tooth tip section (230) of one gear (220) and the second tooth tip section (240) of another gear (220) when meshing is equal to 1.

2. The variable gear pump according to claim 1, characterized in that, The variable gear pump includes: An auxiliary ring assembly (30) includes an auxiliary ring (310) disposed on the outer peripheral surface of the second tooth tip section (240) of the gear assembly (20). The auxiliary ring (310) is connected to the housing (10). The auxiliary ring (310) is clearance-fitted with the outer peripheral surface of the second tooth tip section (240) to seal the oil at the corresponding second tooth tip section (240).

3. The variable gear pump according to claim 1, characterized in that, The outer casing (10) includes: A bottom housing assembly (110), in which at least a portion of the gear assembly (20) is disposed, and the bottom housing assembly (110) is provided with an oil drain port (120) and an oil suction port (130); A cover plate (140) is disposed on the bottom shell assembly (110) to form a sealed cavity (150) for placing the gear assembly (20).

4. The variable gear pump according to claim 3, characterized in that, The two gear assemblies (20) are respectively: A drive gear set (40) is disposed in the sealed cavity (150). The drive gear set (40) includes a drive gear (410) and a drive shaft (420). The drive gear (410) is fixedly sleeved on the drive shaft (420), and the drive shaft (420) is connected to a motor so that the motor drives the drive gear (410) to rotate. A driven gear set (50) is disposed in the sealed cavity (150) and includes a driven gear (510) and a driven shaft (520). The driven gear (510) is fixedly sleeved on the driven shaft (520) and meshes with the driving gear (410).

5. The variable gear pump according to claim 4, characterized in that, The variable gear pump includes: Two support ring assemblies (60), each of the support ring assemblies (60) includes a first support ring (610) and a second support ring (620) connected together. The first support rings (610) of the two support ring assemblies (60) are both sleeved on the drive shaft (420) and are respectively located at both ends of the drive gear (410). The drive shaft (420) and the drive gear (410) are rotatably arranged relative to the first support rings (610) of the two support ring assemblies (60). The second support rings (620) of the two support ring assemblies (60) are both sleeved on the driven shaft (520) and are respectively located at both ends of the driven gear (510). The driven shaft (520) and the driven gear (510) are rotatably arranged relative to the second support rings (620) of the two support ring assemblies (60).

6. The variable gear pump according to claim 5, characterized in that, The second tooth tip section (240) of the driving gear (410) is disposed at one of the driving gear (410) near the bottom shell assembly (110) and the cover plate (140), and the second tooth tip section (240) of the driven gear (510) is disposed at the other of the driven gear (510) near the bottom shell assembly (110) and the cover plate (140).

7. The variable gear pump according to claim 2, characterized in that, The auxiliary ring group (30) includes two auxiliary rings (310), and the two auxiliary rings (310) are arranged in a one-to-one correspondence with the two second tooth tip sections (240). Each auxiliary ring (310) is also provided with a pressure equalization groove (311).

8. The variable gear pump according to claim 5, characterized in that, The cover plate (140) is provided with an adjusting oil hole (141), which is correspondingly provided with the second support ring (620) located above the driven gear (510); An oil storage tank (112) is provided on the bottom surface (111) of the bottom shell assembly (110). One end of the oil storage tank (112) is connected to the bottom of the second support ring (620) located below the driven gear (510), and the other end of the oil storage tank (112) is connected to the oil drain port (120). The second support ring (620) located above the driven gear (510) is pressured by injecting control oil into the regulating oil hole (141), so that the driven gear (510) moves axially under the pressure difference between the oil reservoir (112) and the regulating oil hole (141).

9. The variable gear pump according to claim 8, characterized in that, Both the first support ring (610) and the second support ring (620) are circular ring structures, and the thickness of the first support ring (610) is greater than the thickness of the second support ring (620). The second support ring (620) is movably arranged relative to the first support ring (610) along the axial direction so as to drive the driven gear (510) to move along the axial direction under the action of pressure difference.

10. The variable gear pump according to claim 8, characterized in that, The bottom shell assembly (110) also includes two bottom shell connecting shaft holes (113), which are used to install one end of the drive shaft (420) and the driven shaft (520), respectively. A portion of the oil reservoir (112) is connected to the oil drain port (120), and another portion of the oil reservoir (112) is arranged around the bottom housing connecting shaft hole (113) corresponding to the driven shaft (520) to transmit the output pressure of the oil drain port (120) to the bottom of the driven gear (510).

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