A gear pump with a self-lubricating sealing structure

Abstract

This utility model discloses a gear pump with a self-lubricating sealing structure. The gear pump includes a pump cover and a liquid storage tank with meshing gears. The pump cover has inlet and outlet ports. The improvement lies in the following: a leakage hole is opened at the bottom of the liquid storage tank, and a sealed chamber is provided below it, through which the motor shaft passes. An annular sealing gasket fitted onto the motor shaft is provided in the sealed chamber. This sealing gasket has an inner layer that mates with the shaft and an outer layer that mates with the chamber wall, forming an annular collection groove with an open top. The outlet of the leakage hole is directly above this collection groove. Simultaneously, the top of the inner layer of the sealing gasket has an integral conical extension that slopes downwards and converges towards the shaft. During operation, a small amount of liquid drips into the collection groove through the leakage hole, lubricating and cooling the sealing gasket. The conical extension guides the liquid distribution, effectively reducing frictional temperature rise and wear. This utility model has a reasonable structure, significantly improving the reliability and lifespan of the gear pump shaft seal, and is suitable for liquid transportation applications requiring long-term stable operation.

Description

Technical Field

[0001] This utility model relates to a fluid conveying device, specifically to a gear pump with a self-lubricating sealing structure. Background Technology

[0002] Gear pumps are a common type of positive displacement pump, widely used in automobiles, construction machinery, hydraulic systems, and lubrication systems. Their basic working principle is as follows: the rotational motion of a pair of meshing gears (driving gear and driven gear) within a sealed pump chamber creates a partial vacuum on the side where the gears disengage. This vacuum draws liquid in through the inlet, and as the gears rotate, the liquid is drawn into the meshing area. Subsequently, on the side where the gears engage, the liquid is compressed and discharged under high pressure from the outlet.

[0003] During the long-term operation of gear pumps, the motor shaft driving the gears needs to pass through the pump body and connect to an external power source. Therefore, a shaft seal (usually a gasket or mechanical seal) must be installed at the point where the shaft passes through the pump body to prevent liquid leakage from the pump chamber along the shaft. However, gear pumps, especially those conveying liquids with a certain temperature or containing small particles, face severe challenges in their shaft seal components. On the one hand, the high-speed rotation of the motor shaft generates continuous dry friction or boundary friction between itself and the inner lip of the gasket, producing a large amount of heat, causing the rubber material to age, harden, or even ablate, accelerating seal failure. On the other hand, the lack of effective lubrication and cooling in the sealing area further exacerbates wear. Although some designs attempt to introduce lubricant from the outside, these designs are complex and may introduce contamination; relying solely on the wear resistance of the gasket itself cannot solve the fundamental problem of heat generation.

[0004] In existing technologies, few simple and reliable structures can cleverly utilize the clean working fluid, filtered through gear meshing and supplied by the pump itself, to continuously, micro-volume, and actively lubricate and cool the shaft seal. Therefore, developing a gear pump shaft seal structure that can achieve self-lubrication, effectively reduce the shaft seal operating temperature, and significantly extend the seal life is of great significance for improving the overall reliability and service life of gear pumps. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a gear pump with an ingenious structure that can achieve self-lubrication and cooling and effectively extend the life of the shaft seal.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A gear pump with a self-lubricating sealing structure includes a pump cover and a liquid storage tank with meshing gears. The pump cover has an inlet and an outlet. Its features are:

[0008] A leakage hole is provided at the bottom of the liquid storage tank;

[0009] A sealed chamber is located below the leakage hole, and the motor shaft that drives the gear passes through the sealed chamber;

[0010] An annular sealing gasket is disposed in the sealing cavity and sleeved on the motor shaft. The sealing gasket has an inner layer that seals with the motor shaft and an outer layer that seals with the inner wall of the sealing cavity.

[0011] An annular collection groove with an open top is formed between the inner layer and the outer layer, and the outlet of the leakage hole corresponds to the area above the annular collection groove;

[0012] The inner layer of the sealing gasket has an integrally formed tapered extension at its top end. The extension slopes downward and inward toward the axis of the motor shaft from the connection point with the inner layer.

[0013] Furthermore, the sealing gasket is made of an elastic rubber material.

[0014] Furthermore, it also includes a wear-resistant plate covering the upper opening of the liquid storage tank and a metal inner liner plate embedded in the liquid storage tank; the wear-resistant plate is fixed to the side of the pump cover facing the liquid storage tank; the metal inner liner plate is fixedly bonded to the pump body material constituting the liquid storage tank by injection molding.

[0015] Furthermore, the metal inner liner plate has a drive shaft hole and a driven shaft hole, which are respectively for the motor shaft connecting the drive gear and the gear shaft supporting the driven gear to pass through.

[0016] Furthermore, the main body of the metal liner plate is a groove-shaped base that matches the shape of the inner cavity of the liquid storage tank. The edge of the groove-shaped base extends radially outward to form multiple filling wing plates. The pump body material covers and fixes the outer surface of each filling wing plate and the groove-shaped base.

[0017] Furthermore, the cross-sectional profile of the grooved substrate is V-shaped.

[0018] Furthermore, each of the injection wing plates is provided with a through hole, through which the pump body material flows and covers part of the inner and outer surfaces of the groove-shaped substrate.

[0019] Furthermore, the upper surface of the metal liner plate and the lower surface of the wear-resistant plate together form the working surface of the pump cavity that accommodates the gear.

[0020] Furthermore, the inclined surface of the tapered extension is configured to guide and collect liquid flowing or dripping along the motor shaft.

[0021] Furthermore, the elastic rubber material is nitrile rubber or fluororubber.

[0022] The beneficial effects of this utility model are as follows:

[0023] Achieving continuous self-lubrication and cooling: A very small amount of clean working fluid is allowed to slowly seep into the sealing chamber below through a leakage hole at the bottom of the reservoir, and then precisely drip or flow into the annular collection groove of the sealing gasket. Driven by the rotation of the motor shaft, this fluid continuously lubricates the friction pair between the inner layer of the sealing gasket and the shaft, while carrying away the heat generated by friction, fundamentally solving the problem of premature failure of the shaft seal due to overheating caused by dry friction.

[0024] Optimized lubricant distribution and retention: The ingeniously designed tapered extension at the top of the inner layer of the sealing gasket. Its inclined surface effectively guides and concentrates liquid flowing down the shaft or splashing from the collection tank to the critical contact area between the inner layer and the motor shaft, ensuring that the lubricant covers the main friction surfaces. Simultaneously, this structure helps form and maintain a small liquid film in the sealing area, enhancing lubrication performance.

[0025] Double sealing guarantee: The sealing gasket adopts a double-layer sealing structure, with the inner layer tightly fitting into the motor shaft and the outer layer tightly abutting against the chamber wall, providing reliable static and dynamic sealing. The presence of the annular collection groove does not affect its overall sealing function; on the contrary, it enhances the durability of the dynamic seal through lubrication.

[0026] Simple and reliable structure, no external system required: The entire self-lubricating structure is completely built into the pump body, utilizing the pump's own working fluid. No additional lubrication oil circuit, pumping device or cooling system is needed, resulting in low cost, high reliability and almost no increase in system complexity.

[0027] The overall lifespan is improved by combining wear-resistant structure: When combined with optional wear-resistant plates and metal inner lining plates, the gear pump of this utility model has been optimized in the core gear meshing wear-resistant area and the key shaft seal lubrication area, which comprehensively improves the service life and volumetric efficiency stability of the pump under high pressure, high speed or particulate conditions. Attached Figure Description

[0028] Figure 1 This is a partial cross-sectional view of the gear pump according to an embodiment of the present invention, focusing on the sealing and lubrication structure.

[0029] Figure 2 for Figure 1 A schematic diagram of the structure of the central sealing gasket.

[0030] Figure 3 This is a schematic diagram of the structure of the metal lining plate of this utility model.

[0031] Figure 4 This is a schematic diagram of the liquid storage tank of this utility model.

[0032] Explanation of the labels in the diagram:

[0033] 1-Pump cover, 11-Inlet, 12-Outlet, 2-Storage tank, 21-Leakage hole, 3-Sealed chamber, 4-Motor shaft, 5-Sealing gasket, 51-Inner layer, 52-Outer layer, 53-Annular collection trough, 54-Conical extension, 6-Wear-resistant plate, 7-Metal inner liner, 71-Groove type base, 72-Injection wing plate, 73-Through hole, 74-Drive shaft hole, 75-Driven shaft hole. Detailed Implementation

[0034] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings and embodiments. 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.

[0035] Please see Figure 1 and Figure 4 This utility model provides a gear pump with a self-lubricating sealing structure, the basic structure of which includes a pump cover 1 and a liquid storage tank 2. The pump cover 1 is provided with a liquid inlet 11 and a liquid outlet 12. The liquid storage tank 2 is equipped with a driving gear and a driven gear that mesh with each other (the meshing relationship is not fully shown in the figure).

[0036] The core improvement of this invention lies in the lubrication structure of the shaft seal. A small leakage hole 21 is machined at the bottom of the liquid storage tank 2. Directly below the leakage hole 21, an independent sealed chamber 3 is machined or formed on the pump body. The motor shaft 4, which drives the drive gear, passes through the liquid storage tank 2 area, the leakage hole 21, and finally through the sealed chamber 3 from top to bottom.

[0037] An annular sealing gasket 5 is installed inside the sealed chamber 3. This gasket 5 is preferably made of an elastic, wear-resistant material such as nitrile rubber or fluororubber. The sealing gasket 5 includes an inner layer 51 and an outer layer 52. The inner layer 51 is press-fitted to the outer surface of the motor shaft 4 to achieve a rotary dynamic seal. The outer layer 52 is press-fitted to the inner wall of the sealed chamber 3 or sealed by compression to achieve a static seal. Crucially, an annular collecting groove 53 with an open top is formed between the inner layer 51 and the outer layer 52. The outlet of the leakage hole 21 at the bottom of the liquid storage tank 2 is vertically aligned with (or slightly offset but ensuring liquid inflow) the upper opening area of ​​this annular collecting groove 53.

[0038] Furthermore, at the top of the inner layer 51 of the sealing gasket 5 (i.e., the end near the liquid storage tank 2), a tapered extension 54 is integrally formed. Starting from its connection with the main body of the inner layer 51, the extension 54 gradually slopes and converges downward (i.e. away from the liquid storage tank) and inward (i.e. towards the center of the axis of the motor shaft 4), forming a funnel-shaped guide structure.

[0039] Working Principle: When the gear pump is working normally, the reservoir 2 is filled with pressurized liquid. A very small amount of liquid will slowly seep out through the leak hole 21 at the bottom. Since the leak hole 21 is directly below the annular collection tank 53, the seeping liquid will enter the collection tank 53 in the form of drips or a thin stream. When the motor shaft 4 rotates at high speed, it will drive the liquid in the collection tank 53 to move. This liquid lubricates the friction contact surface between the inner layer 51 of the sealing gasket 5 and the motor shaft 4, and absorbs the heat generated by friction, thus playing a cooling role. At the same time, the inclined surface of the tapered extension 54 can effectively guide and collect the liquid that may flow down the shaft surface or the liquid splashed from the collection tank 53 due to rotation to the close contact area between the inner layer 51 and the motor shaft 4 that needs the most lubrication, optimizing the distribution and utilization efficiency of the lubricant, and ensuring continuous and effective lubrication and cooling.

[0040] Please see Figure 3 In a more preferred embodiment, to simultaneously address the gear end face wear problem, the gear pump of this invention may further include a wear-resistant plate 6 and a metal inner liner 7. The wear-resistant plate 6 is fixedly installed on the surface of the pump cover 1 facing the liquid storage tank 2 by screws or adhesive. The metal inner liner 7 is then integrally bonded to the pump body material (such as engineering plastic) constituting the liquid storage tank 2 through an injection molding process. The main body of the metal inner liner 7 is a groove-shaped base 71 that matches the shape of the inner cavity of the liquid storage tank 2, and its cross-section is preferably V-shaped to conform to the gear contour. Multiple (e.g., four) injection vanes 72 extend radially outward from the edge of the groove-shaped base 71, and each injection vane 72 has a through hole 73. During injection molding, the molten pump body material covers all the injection vanes 72 and the outer surface of the groove-shaped base 71, and fills part of the inner surface of the base 71 through the through hole 73, forming a very strong mechanical interlock to ensure that the metal inner liner 7 never loosens. The metal liner plate 7 is machined with a drive shaft hole 74 and a driven shaft hole 75, through which the motor shaft 4 and the driven gear shaft (not shown in the figure) pass, respectively. Finally, the upper surface of the metal liner plate 7 and the lower surface of the wear-resistant plate 6 are parallel to each other, together forming a smooth and wear-resistant working surface of the pump cavity, which accommodates and protects the meshing gears.

[0041] In summary, this invention provides a gear pump solution with longer service life, more reliable operation, and lower maintenance requirements by integrating a unique self-lubricating sealing structure into the gear pump and optionally combining it with high-performance wear-resistant components.

[0042] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A gear pump with a self-lubricating sealing structure, comprising a pump cover and a liquid storage tank with meshing gears, wherein the pump cover is provided with an inlet and an outlet, characterized in that: A leakage hole is provided at the bottom of the liquid storage tank; A sealed chamber is located below the leakage hole, and the motor shaft that drives the gear passes through the sealed chamber; An annular sealing gasket is disposed in the sealing cavity and sleeved on the motor shaft. The sealing gasket has an inner layer that seals with the motor shaft and an outer layer that seals with the inner wall of the sealing cavity. An annular collection groove with an open top is formed between the inner layer and the outer layer, and the outlet of the leakage hole corresponds to the area above the annular collection groove.

2. The gear pump with a self-lubricating sealing structure according to claim 1, characterized in that, The inner layer of the sealing gasket has an integrally formed conical extension at its top end. This extension slopes downward and inward toward the axis of the motor shaft from the connection point with the inner layer.

3. The gear pump with a self-lubricating sealing structure according to claim 1, characterized in that, The sealing gasket is made of elastic rubber material.

4. The gear pump with a self-lubricating sealing structure according to claim 1, characterized in that, It also includes a wear-resistant plate covering the upper opening of the liquid storage tank and a metal inner lining plate embedded in the liquid storage tank; The wear-resistant plate is fixed to the side of the pump cover facing the liquid storage tank; The metal liner plate is fixedly bonded to the pump body material constituting the liquid storage tank by injection molding.

5. The gear pump with a self-lubricating sealing structure according to claim 4, characterized in that, The metal inner liner plate has a drive shaft hole and a driven shaft hole, which are respectively for the motor shaft connecting the drive gear and the gear shaft supporting the driven gear to pass through.

6. The gear pump with a self-lubricating sealing structure according to claim 4, characterized in that, The main body of the metal liner plate is a groove-shaped base that matches the shape of the inner cavity of the liquid storage tank. The edge of the groove-shaped base extends radially outward to form multiple filling wing plates. The pump body material covers and fixes the outer surface of each filling wing plate and the groove-shaped base.

7. The gear pump with a self-lubricating sealing structure according to claim 6, characterized in that, The cross-sectional profile of the grooved substrate is V-shaped.

8. The gear pump with a self-lubricating sealing structure according to claim 6, characterized in that, Each of the injection vanes is provided with a through hole, through which the pump body material flows and covers part of the inner and outer surfaces of the groove-shaped substrate.

9. The gear pump with a self-lubricating sealing structure according to claim 4, characterized in that, The upper surface of the metal liner plate and the lower surface of the wear-resistant plate together form the working surface of the pump cavity that accommodates the gear.

10. The gear pump with a self-lubricating sealing structure according to claim 2, characterized in that, The inclined surface of the tapered extension is configured to guide and collect liquid flowing or dripping along the motor shaft.

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