A new type of gear oil pump
By introducing floating side plates and low-pressure lubrication channels into the gear oil pump, the problems of internal leakage caused by rotor wear and insufficient bearing lubrication are solved, achieving the technical effects of high-efficiency sealing, self-lubrication, and noise and vibration reduction.
Patent Information
- Application Number
- CN202522773049.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-27
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-12-27
AI Technical Summary
After long-term operation, the rotor end face of the existing gear oil pump wears, which leads to an increase in axial clearance, causing internal leakage and a decrease in volumetric efficiency. At the same time, the lack of effective lubrication of the pump shaft bearing results in high frictional loss and short service life.
A novel gear oil pump with floating side plates was designed. It automatically compensates for axial clearance by using high-pressure oil to generate axial thrust through the oil chamber connection structure, and integrates a low-pressure lubrication channel in the outer cover to achieve autonomous lubrication and cooling.
It effectively maintains sealing performance, improves volumetric efficiency, extends service life, reduces noise and vibration, and simplifies the lubrication structure.
Smart Images
Figure CN224931829U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of hydraulic pump technology, and in particular to a novel gear oil pump. Background Technology
[0002] Internal gear oil pumps are widely used in industrial fields such as hydraulic systems, machine tool lubrication systems, and fuel delivery due to their advantages of compact structure, small size, light weight, and low flow pulsation. These pumps primarily rely on the meshing motion between the teeth of the inner and outer rotors mounted within the pump body. Combined with the separation effect of a crescent-shaped baffle, the pump chamber is divided into an oil suction zone and an oil pressure zone, thereby utilizing volume changes to achieve fluid intake and discharge.
[0003] However, in existing conventional gear oil pumps, during long-term continuous operation, relative sliding friction inevitably occurs between the rotor end face and the inner wall of the pump casing or the fixed side plate. With increasing usage time, this continuous mechanical friction leads to wear on the sealing surfaces, resulting in a gradual increase in the axial clearance between the rotor and the side plate. This increased axial clearance compromises the pump chamber's sealing performance, directly causing severe internal leakage of oil from the high-pressure area to the low-pressure area through the gap.
[0004] Increased internal leakage not only significantly reduces the volumetric efficiency of the oil pump, leading to insufficient output pressure and decreased flow, but also causes abnormally high oil temperature due to the throttling effect of the oil in the gap, further deteriorating the working environment. Furthermore, some existing gear pump structures often lack an effective forced lubrication mechanism for the pump shaft bearings, causing the bearings to rely primarily on splash lubrication or dry friction, accelerating the wear of core components and ultimately shortening the overall service life of the equipment.
[0005] Therefore, this utility model proposes a novel gear oil pump to overcome the shortcomings of the prior art. Utility Model Content
[0006] In view of the problems existing in the conventional gear oil pump, such as the rotor end face being prone to wear after long-term operation, leading to increased axial clearance, which in turn causes serious internal leakage, a significant decrease in volumetric efficiency, and the lack of effective forced lubrication of the pump shaft bearing resulting in high frictional loss and short service life, this utility model aims to provide a new type of gear oil pump with an improved structure that can effectively solve the above problems.
[0007] This utility model provides a novel gear oil pump, comprising: an outer cover, a pump shaft rotatably inserted and installed in the central shaft hole of the outer cover, an inner rotor coaxially fixed to the pump shaft by a key connection, and an outer rotor eccentrically accommodated in the inner cavity of the outer cover. A crescent-shaped partition is also fixedly provided in the inner cavity of the outer cover. The inner rotor and the outer rotor form a meshing area on one side of the inner cavity of the outer cover, and the crescent-shaped partition is located in the crescent-shaped area between the inner rotor and the outer rotor where they are not meshed. A floating side plate is also provided.
[0008] The floating side plate has a floating compensation structure that can move slightly along the axial direction to fit the rotor end face. The floating side plate is located in the inner cavity of the outer cover and on one side of the axial direction of the inner rotor and the outer rotor. The inner end face of the floating side plate slides against the end faces of the inner rotor and the outer rotor. A back pressure compensation cavity is formed between the outer side of the floating side plate and the bottom wall of the inner cavity of the outer cover. A pressure oil cavity is opened through the plate body of the floating side plate.
[0009] Furthermore, the inner rotor, the outer rotor, and the floating side plate are combined by hydraulic pressure adaptive clamping. One end of the oil pressure chamber is connected to the high-pressure oil outlet side formed by the meshing area, and the other end of the oil pressure chamber is connected to the back pressure compensation chamber. The thrust generated by the high-pressure oil introduced into the back pressure compensation chamber is used to press the floating side plate against the inner rotor and the outer rotor, thereby automatically compensating for the axial clearance.
[0010] Preferably, a low-pressure lubrication channel is formed by drilling or casting in the solid wall of the outer cover. The inlet end of the low-pressure lubrication channel is connected to the high-pressure oil outlet side of the meshing area of the inner rotor and the outer rotor. The outlet end of the low-pressure lubrication channel extends and is connected to the fitting gap between the pump shaft and the central shaft hole of the outer cover, thereby using its own pumping medium to force lubricate and cool the bearing.
[0011] Preferably, a miniature throttling orifice or pressure limiting valve is installed in the flow path of the low-pressure lubrication channel to reduce the pressure of the high-pressure oil flowing through the low-pressure lubrication channel and prevent the high pressure from directly impacting the bearing oil film.
[0012] Preferably, the floating side plate has a recessed unloading groove on the end face that fits the inner rotor and the outer rotor. The position of the unloading groove corresponds to the meshing contact area of the teeth of the inner rotor and the outer rotor, which is used to eliminate the pressure shock caused by the oil trapping phenomenon.
[0013] Preferably, the outline shape of the unloading groove is adapted to the projected shape of the trapped oil closed volume formed by the inner rotor and the outer rotor during the meshing process, and the unloading groove is connected to the oil pump's low-pressure suction area or high-pressure oil pressure area through an internal flow channel to ensure that the trapped oil can be discharged or replenished in a timely manner.
[0014] Preferably, the crescent-shaped partition has a concave arc surface and a convex arc surface. The concave arc surface forms a sliding seal with the tooth tip circumferential surface of the inner rotor, and the convex arc surface forms a sliding seal with the tooth tip circumferential surface of the outer rotor, thereby tightly separating the inner cavity of the outer cover into an oil suction area and an oil pressure area.
[0015] Preferably, the outer circumferential edge of the floating side plate and the inner cavity side wall of the outer cover are fitted with a clearance. The floating side plate is also provided with an anti-rotation pin or positioning protrusion to prevent it from rotating with the rotor, so as to ensure that it does not rotate circumferentially when performing axial compensation movement.
[0016] Preferably, the number of oil pressure chambers connected is at least one, and the oil pressure chamber connection is a through hole or waist-shaped groove extending along the thickness direction of the floating side plate, so as to ensure that the high-pressure oil can smoothly enter the back pressure chamber.
[0017] This utility model has the following beneficial effects:
[0018] 1. This utility model, by setting a floating side plate with a pressure oil chamber connection structure, uses high-pressure oil from the pressure oil zone to introduce back pressure compensation chamber to generate axial thrust, which solves the problem of internal leakage caused by increased clearance due to rotor end face wear in existing gear pumps. It achieves the technical effect of automatically compensating for axial clearance, maintaining high-efficiency sealing, and significantly improving the volumetric efficiency and service life of the oil pump.
[0019] 2. This utility model integrates a low-pressure lubrication channel with throttling and pressure reduction function inside the outer cover, which guides the high-pressure side oil to the pump shaft bearing. This solves the problem of pump shaft bearings lacking forced lubrication or needing to rely on complex external pipelines for lubrication in the prior art. It achieves the technical effects of using its own pumping medium to achieve self-lubrication and cooling, simplifying the system structure, effectively reducing frictional heat and extending bearing life.
[0020] 3. This utility model solves the problem of instantaneous high-pressure impact and cavitation caused by oil trapping during gear pump meshing by opening an unloading groove with a matching profile at the corresponding meshing area position of the floating side plate and connecting it to the low-pressure or high-pressure area. It achieves the technical effects of eliminating oil trapping pressure, significantly reducing the noise and vibration of the oil pump during operation, and ensuring smooth and stable fluid delivery. Attached Figure Description
[0021] Figure 1 This is a three-dimensional schematic diagram of a novel gear oil pump proposed in this utility model;
[0022] Figure 2 This is a schematic diagram of the floating side plate of a novel gear oil pump proposed in this utility model;
[0023] Figure 3This is a schematic diagram of the outer cover of a novel gear oil pump proposed in this utility model;
[0024] Figure 4 This is a schematic diagram of the low-pressure lubrication flow channel of a novel gear oil pump proposed in this utility model.
[0025] Legend:
[0026] 1. Outer cover; 2. Outer rotor; 3. Inner rotor; 4. Pump shaft; 5. Crescent-shaped partition; 6. Low-pressure lubrication channel; 7. Unloading groove; 8. Floating side plate; 9. Oil pressure chamber connection. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.
[0028] Example:
[0029] Please refer to Figures 1 to 4 This utility model provides a novel gear oil pump, which aims to solve the structural defects of existing gear oil pumps, such as increased internal leakage due to rotor end face wear, decreased volumetric efficiency, and limited lifespan due to lack of effective bearing lubrication.
[0030] like Figure 1 and Figure 2 As shown, the main frame of this novel gear oil pump includes an outer cover 1, which serves as the outer shell base and mounting support component, and a core power component and sealing compensation component encapsulated inside the outer cover 1, responsible for fluid transportation. The pump shaft 4 is rotatably inserted into the shaft hole in the center of the outer cover 1, used to receive the torque of external drive sources such as motors and drive the internal components to rotate. The inner rotor 3 is coaxially fixed to the outer circumferential surface of the pump shaft 4 by a key connection, ensuring that the inner rotor 3 and the pump shaft 4 can rotate synchronously without relative slippage. The outer rotor 2 is eccentrically accommodated in the circular inner cavity of the outer cover 1. The outer circumferential surface of the outer rotor 2 and the inner wall of the outer cover 1 form a rotational support fit, allowing the outer rotor 2 to rotate freely within the outer cover 1. The inner rotor 3 has external teeth, and the outer rotor 2 has internal teeth. The external teeth of the inner rotor 3 and the internal teeth of the outer rotor 2 form a partial meshing connection on one side of the inner cavity of the outer cover 1. The periodic change of the pump oil chamber volume is achieved through the meshing motion of the two.
[0031] A crescent-shaped partition 5 is also fixedly installed in the inner cavity of the outer cover 1. The crescent-shaped partition 5 is precisely positioned in the crescent-shaped space between the inner rotor 3 and the outer rotor 2 where they are not engaged. The crescent-shaped partition 5 has a concave arc surface and a convex arc surface. The concave arc surface forms a sliding seal with the tooth tip circumferential surface of the inner rotor 3, and the convex arc surface forms a sliding seal with the tooth tip circumferential surface of the outer rotor 2. In this way, the crescent-shaped partition 5 tightly divides the inner cavity of the outer cover 1 into an oil suction area and an oil pressure area, preventing the cross-contamination of high and low pressure oil.
[0032] To achieve automatic compensation of end face clearance and high volumetric efficiency, the new gear oil pump also includes a floating side plate 8. The floating side plate 8 is located in the inner cavity of the outer cover 1 and on one side of the axial direction of the inner rotor 3 and the outer rotor 2. The inner end face of the floating side plate 8 directly slides against the end faces of the inner rotor 3 and the outer rotor 2, which plays a role in end face sealing. At the same time, a back pressure compensation cavity is formed between the outer side of the floating side plate 8 and the bottom wall of the inner cavity of the outer cover 1. The back pressure compensation cavity is used to contain high pressure oil and apply axial thrust to the floating side plate 8.
[0033] A pressure oil chamber 9 is provided through the body of the floating side plate 8, such as... Figure 2 As shown, the number of oil pressure chamber connections 9 is at least one, and the oil pressure chamber connection 9 is a through hole or waist-shaped groove that runs through the thickness direction of the floating side plate 8. One end of the oil pressure chamber connection 9 is directly connected to the high-pressure oil outlet side formed by the meshing area of the inner rotor 3 and the outer rotor 2, and the other end is connected to the back pressure compensation chamber. This allows the high-pressure oil generated during operation to enter the back pressure compensation chamber through the oil pressure chamber connection 9. The hydraulic pressure keeps the floating side plate 8 pressed tightly against the end faces of the inner rotor 3 and the outer rotor 2, thereby automatically moving axially to compensate when wear occurs on the rotor end faces and maintaining a very small working clearance.
[0034] To address the technical challenges of limited service life due to lack of effective lubrication of pump shaft bearings and the complex structure of traditional external lubrication pipelines, this novel gear oil pump integrates a low-pressure lubrication channel 6 inside the outer cover 1. Furthermore, the low-pressure lubrication channel 6 forms a specific fluid conduction and cooperation relationship with the aforementioned outer cover 1 and pump shaft 4.
[0035] Please refer to the following carefully. Figure 3 and Figure 4 The core structure will be described in detail below:
[0036] The outer cover 1 has a low-pressure lubrication channel 6 formed inside its solid wall by precision drilling or direct casting. The low-pressure lubrication channel 6 serves as an internal bridge connecting the high-pressure oil circuit and the bearing friction pair. Its inlet end is directly connected to the high-pressure area where the inner rotor 3 and outer rotor 2 mesh and output oil. At this location, the high-pressure oil generated by gear extrusion is collected when the oil pump is working. The outlet end of the low-pressure lubrication channel 6 extends inside the solid wall and eventually penetrates to the inner wall of the central shaft hole of the outer cover 1, directly connecting to the fitting clearance between the pump shaft 4 and the central shaft hole of the outer cover 1, i.e., the bearing fitting clearance. This structural design utilizes the pressure difference of the oil pump itself to introduce part of the high-pressure oil into the low-pressure lubrication channel 6.
[0037] Meanwhile, to prevent excessively high oil pressure from damaging the bearing oil film or causing seal failure, a miniature throttling orifice or pressure limiting valve is installed in the flow path of the low-pressure lubrication channel 6 with an interference fit. This miniature throttling orifice or pressure limiting valve is used to throttle and reduce the pressure of the high-pressure oil flowing through the low-pressure lubrication channel 6, transforming the original high-pressure oil into low-pressure oil suitable for bearing lubrication and cooling. This structural design of high-pressure diversion, throttling and pressure reduction, and fixed-point lubrication ensures that the treated oil can continuously enter the rotational fit gap between the pump shaft 4 and the outer cover 1. This not only achieves forced lubrication and cooling of the pump shaft 4, removing the heat generated by high-speed rotation, but also uses the formed stable oil film to provide auxiliary support for the pump shaft 4, significantly extending the service life of the pump shaft 4 and the bearing.
[0038] Based on the above embodiments, the present invention may further include the following preferred technical solutions:
[0039] As a preferred embodiment, to solve the problems of pressure shock, noise, and vibration caused by oil trapping during gear meshing, please refer to... Figure 2 The floating side plate 8 has a recessed unloading groove 7 on the end face that fits the inner rotor 3 and the outer rotor 2. The position of the unloading groove 7 is precisely corresponding to the meshing contact area of the teeth of the inner rotor 3 and the outer rotor 2, that is, the area where the gear forms a closed volume during the process of disengaging and re-meshing.
[0040] As another preferred embodiment, in order to eliminate trapped oil pressure to the greatest extent and ensure the smoothness of fluid delivery, the outline shape of the unloading groove 7 is adapted to the projection shape of the trapped oil closed volume formed by the inner rotor 3 and the outer rotor 2 during meshing. Through this shape matching design, the unloading groove 7 can effectively cover the entire trapped oil area. At the same time, the unloading groove 7 is connected to the oil pump's suction low-pressure area or pressure high-pressure area through the flow channel inside the floating side plate 8 or the outer cover 1, so that the oil trapped between the teeth can be discharged in time before compression or replenished in time before vacuum is formed, thereby eliminating the high pressure impact or cavitation phenomenon in the trapped oil area.
[0041] In another preferred embodiment, to ensure the stability and accuracy of the floating side plate 8 during axial clearance compensation and to prevent it from rotating circumferentially under the influence of the rotor's rotational friction, a clearance fit is used between the outer circumferential edge of the floating side plate 8 and the inner cavity sidewall of the outer cover 1. This ensures that the floating side plate 8 can move freely along the axial direction while limiting its radial displacement. At the same time, the floating side plate 8 is also provided with anti-rotation pins or positioning protrusions to prevent it from rotating with the rotor. These anti-rotation pins or positioning protrusions cooperate with the corresponding grooves or holes on the outer cover 1 to ensure that the floating side plate 8 is always kept at the designed angular position, ensuring that the unloading groove 7 and the oil pressure chamber communication 9 are accurately positioned.
[0042] As another preferred embodiment, in order to further improve the response speed and compensation effect of the floating side plate 8, the number of oil pressure chamber connections 9 can be set to multiple according to the actual working conditions, and the oil pressure chamber connections 9 are evenly distributed along the circumference of the floating side plate 8 at the corresponding positions of the high pressure zone. By using multi-point oil inlet, the pressure in the back pressure compensation chamber is established more quickly and evenly, avoiding the floating side plate 8 from tilting or getting stuck due to uneven force, and ensuring that the clamping force on the rotor end face is always stable and appropriate.
[0043] The working principle of this novel gear oil pump is as follows:
[0044] When the oil pump starts and enters the working state, the external power source such as the motor drives the pump shaft 4 to start rotating. The pump shaft 4 drives the inner rotor 3 to rotate synchronously through the key connection. The inner rotor 3 drives the outer rotor 2 to rotate eccentrically around its own axis in the inner cavity of the outer cover 1 by the meshing of the tooth surfaces. As the rotor rotates, the teeth of the inner rotor 3 and the outer rotor 2 gradually disengage in the oil suction area, and the inter-tooth volume increases to form a negative pressure that draws in the oil. In the oil pressure area, the teeth gradually engage, and the inter-tooth volume decreases to squeeze out the oil. Throughout this process, the crescent-shaped partition 5 keeps the oil suction area and the oil pressure area tightly separated to ensure unidirectional oil delivery.
[0045] During this process, the high-pressure oil generated in the pressure oil zone will continuously enter the back pressure compensation chamber on the back of the floating side plate 8 through the pressure oil chamber 9 on the floating side plate 8. As the system pressure is established, the hydraulic pressure in the back pressure compensation chamber acts on the back of the floating side plate 8, generating an axial thrust that presses the floating side plate 8 tightly against the end faces of the inner rotor 3 and the outer rotor 2. When the rotor end faces produce a small wear gap due to long-term friction, the high-pressure oil in the back pressure compensation chamber pushes the floating side plate 8 to move automatically towards the rotor side to compensate, always maintaining a very small working gap, effectively preventing high-pressure oil from leaking into the low-pressure area through the end face gap, and ensuring the high volumetric efficiency of the oil pump.
[0046] Meanwhile, some of the high-pressure oil in the pressure zone is introduced into the low-pressure lubrication channel 6 inside the outer cover 1. After being depressurized by the micro throttling orifice or pressure limiting valve integrated in the channel, it is transformed into low-pressure lubricating oil and continuously injected into the bearing clearance between the pump shaft 4 and the outer cover 1. This provides forced lubrication and cooling for the high-speed rotating pump shaft 4, removes frictional heat, and forms a bearing oil film. Meanwhile, the trapped oil in the closed volume generated during gear meshing is promptly guided to the suction chamber or pressure chamber through the unloading groove 7 on the end face of the floating side plate 8. This eliminates the instantaneous high-pressure impact caused by the compression of trapped oil, thereby significantly reducing the noise and vibration during the operation of the oil pump and achieving high efficiency, long service life, and quiet operation of the oil pump.
[0047] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.
Claims
1. A novel gear oil pump, comprising: The outer cover (1) and the pump shaft (4) rotatably inserted into the central shaft hole of the outer cover (1), the inner rotor (3) coaxially fixed on the pump shaft (4) by key connection, and the outer rotor (2) eccentrically accommodated in the inner cavity of the outer cover (1), and a crescent partition (5) is also fixedly provided in the inner cavity of the outer cover (1); the outer teeth of the inner rotor (3) and the inner teeth of the outer rotor (2) form a meshing area on one side of the inner cavity of the outer cover (1), and the crescent partition (5) is located in the crescent-shaped area between the inner rotor (3) and the outer rotor (2) where they are not meshed; the novel gear oil pump is characterized in that it further includes a floating side plate (8), the floating side plate (8) being disposed on the outer cover (1) The inner cavity of the cover (1) is located on one side of the axial direction of the inner rotor (3) and the outer rotor (2). The inner end face of the floating side plate (8) is slidably attached to the end face of the inner rotor (3) and the outer rotor (2). A back pressure compensation cavity is formed between the outer side of the floating side plate (8) and the bottom wall of the inner cavity of the outer cover (1). A pressure oil cavity communication (9) is opened through the plate body of the floating side plate (8). One end of the pressure oil cavity communication (9) is connected to the high pressure oil outlet side formed by the meshing area. The other end of the pressure oil cavity communication (9) is connected to the back pressure compensation cavity, so that high pressure oil enters the back pressure compensation cavity and presses the floating side plate (8) against the inner rotor (3) and the outer rotor (2).
2. The novel gear oil pump according to claim 1, characterized in that, The outer cover (1) has a low-pressure lubrication channel (6) formed by drilling or casting in its solid wall. The inlet end of the low-pressure lubrication channel (6) is connected to the high-pressure oil outlet side of the meshing area of the inner rotor (3) and the outer rotor (2). The outlet end of the low-pressure lubrication channel (6) extends and is connected to the fitting gap between the pump shaft (4) and the central shaft hole of the outer cover (1).
3. The novel gear oil pump according to claim 2, characterized in that, The low-pressure lubrication channel (6) is fitted with a micro throttling orifice or pressure limiting valve in the flow path to reduce the oil pressure flowing through the low-pressure lubrication channel (6).
4. The novel gear oil pump according to claim 1, characterized in that, The floating side plate (8) has a recessed unloading groove (7) on the end face of the inner rotor (3) and the outer rotor (2). The position of the unloading groove (7) corresponds to the meshing contact area of the tooth surfaces of the inner rotor (3) and the outer rotor (2).
5. The novel gear oil pump according to claim 4, characterized in that, The outline shape of the unloading groove (7) is adapted to the projection shape of the oil trapping and closed volume formed by the inner rotor (3) and the outer rotor (2) during the meshing process, and the unloading groove (7) is connected to the oil pump's low-pressure suction area or high-pressure oil pressure area through the internal flow channel.
6. The novel gear oil pump according to claim 1, characterized in that, The crescent-shaped partition (5) has an inner concave arc surface and an outer convex arc surface. The inner concave arc surface forms a sliding seal with the tooth tip circumferential surface of the inner rotor (3), and the outer convex arc surface forms a sliding seal with the tooth tip circumferential surface of the outer rotor (2). The crescent-shaped partition (5) divides the inner cavity of the outer cover (1) into an oil suction area and an oil pressure area.
7. The novel gear oil pump according to claim 1, characterized in that, The outer circumferential edge of the floating side plate (8) and the inner cavity sidewall of the outer cover (1) are fitted with a clearance. The floating side plate (8) is also provided with an anti-rotation pin or positioning protrusion to prevent it from rotating with the rotor.
8. The novel gear oil pump according to claim 1, characterized in that, The number of the oil pressure chamber connections (9) is at least one, and the oil pressure chamber connections (9) are through holes or waist-shaped grooves that penetrate along the thickness direction of the floating side plate (8).