A leak-proof flange structure for a motorcycle oil level sensor

Abstract

This invention provides a leak-proof flange structure for a motorcycle fuel level sensor, suitable for two-hole cruiser models. It includes a metal flange, a sealing rubber ring, and mounting bolts. The metal flange has an upwardly extending annular flange on its periphery. The sealing rubber ring has an embedded annular mesh metal skeleton. The upper surface of the bolt mounting hole of the metal flange has an annular groove, within which an aluminum deformable gasket is placed. This invention increases the flange height to surround the sealing area, providing physical restraint when the bolts are tightened, thus precisely controlling the compression of the rubber ring. By adding a metal skeleton inside the rubber sealing ring, the lateral expansion of the rubber after compression is suppressed, improving the fit with the fuel tank opening. Simultaneously, by adding an aluminum deformable gasket to the bolt contact surface, the aluminum plastically deforms and fills the gap in the mounting opening when tightened, achieving a secondary seal.

Description

Technical Field

[0001] This utility model relates to the field of anchoring technology, specifically to a leak-proof flange structure for a motorcycle oil level sensor. Background Technology

[0002] The motorcycle fuel level sensor is a key component for monitoring the fuel level in the fuel tank. It is fixed to the fuel tank mounting port via a flange structure and transmits the fuel level signal to the instrument system. Currently, the industry generally suffers from the following technical deficiencies:

[0003] The flange seal is not reliable enough. Traditional flanges use flat rubber gaskets for compression sealing. However, in two-hole cruiser models, due to the large curvature of the fuel tank mounting port and the special bolt hole spacing (usually 60±2mm), uneven bolt tightening torque during assembly (standard value 8-N·m, actual fluctuation reaches ±30%) can cause the rubber ring compression to run out of control. When the compression is insufficient, micro-gaps (>0.1mm) are generated at the sealing interface, and fuel seeps out along the flange edge. When the compression is excessive, the rubber undergoes permanent deformation, and the sealing stress decays, causing chronic leakage.

[0004] The rubber ring lacks anti-expansion capability, and the existing sealing ring is made of pure rubber (such as nitrile rubber). When the oil temperature rises above 60°C, the rubber volume expansion rate exceeds 15%, and the lateral extrusion force causes the flange to partially detach from the oil tank opening, forming an "arched leakage channel." Industry statistics show that this type of leakage accounts for more than 42% of oil sensor failures in cruiser models.

[0005] The bolt hole sealing blind zone is a problem because the bolt mounting ports of the two-hole flange are directly connected to the fuel tank. Traditional solutions rely on rubber gaskets to cover the holes. However, under vibration conditions, a dynamic gap of 20-50μm is generated between the bolts and the hole walls, allowing fuel to leak through capillary action. This problem is particularly prominent in cruiser models with low-mounted fuel tanks (fuel static pressure > 3kPa).

[0006] Generally, conventional industry solutions have significant limitations: increasing flange thickness leads to a cost increase of about 30%; applying sealant makes maintenance and disassembly difficult, and residual sealant can clog oil passages; and using multi-hole flanges conflicts with the structure of cruiser models. Utility Model Content

[0007] The purpose of this invention is to provide a leak-proof flange structure for a motorcycle oil level sensor, so as to overcome the shortcomings of the prior art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A leak-proof flange structure for a motorcycle oil level sensor, suitable for two-hole cruiser models, includes a metal flange, a sealing rubber ring, and mounting bolts. The metal flange has an upwardly extending annular flange on its periphery, the height of which is 1.5-2 times the thickness of the rubber ring before compression. The sealing rubber ring has an embedded metal skeleton with an annular mesh structure. The upper surface of the bolt mounting hole of the metal flange has an annular groove, in which an aluminum gasket is placed. The thickness of the aluminum gasket is 0.3-0.5 mm greater than the groove depth.

[0010] Furthermore, the inner wall of the annular flange is clearance-fitted with the outer side of the sealing rubber ring, and the flange height is configured as a physical limiting structure when the bolt is tightened.

[0011] Furthermore, the cross-section of the metal skeleton is T-shaped, with its horizontal part embedded in the bottom of the rubber ring and its vertical part extending to 2 / 3 of the height of the rubber ring.

[0012] Furthermore, the aluminum gasket is made of pure aluminum and has radial corrugations on its surface.

[0013] Furthermore, the diameter of the annular groove is 1.5-2 mm larger than that of the bolt mounting hole, and the depth of the groove is 0.8-1.2 mm.

[0014] As can be seen from the above technical solutions, this utility model precisely controls the compression of the rubber ring by increasing the height of the flange to surround the sealing area and providing a physical limiting effect when the bolt is tightened; by adding a metal skeleton inside the rubber sealing ring, the lateral expansion of the rubber after compression is suppressed, improving the fit with the tank opening; at the same time, by adding an aluminum deformation gasket, an aluminum gasket is added to the bolt contact surface, and the aluminum material plastically deforms to fill the gap of the installation opening when tightened, achieving secondary sealing. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the leak-proof flange structure of this utility model;

[0016] Figure 2 This is an assembly drawing of the leak-proof flange structure of this utility model;

[0017] In the diagram: 1. Metal flange; 2. Sealing rubber ring; 3. Mounting bolts; 4. Metal frame; 5. Aluminum gasket. Detailed Implementation

[0018] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] like Figure 1-2The leak-proof flange structure shown is for a motorcycle fuel level sensor and is suitable for two-hole cruiser models (fuel tank mounting hole distance 60±2mm, mounting surface curvature radius R=150mm). It includes a metal flange 1, a sealing rubber ring 2, and mounting bolts 3. The outer periphery of the metal flange 1 is provided with an upwardly extending annular flange. The inner sidewall of the annular flange is clearance-fitted with the outer side of the sealing rubber ring 2. The flange height is configured as a physical limiting structure when the bolts 3 are tightened.

[0020] The metal flange 1 described in this preferred embodiment is made of 304 stainless steel with a thickness of 3mm; the height of the annular flange is 5.2mm (1.73 times the original thickness of the rubber ring of 3.0mm), the inner diameter is 72mm, and it is clearance-fitted with the sealing ring with a single-sided clearance of 0.3mm; when the bolts are tightened, the flange is pressed down until the top surface of the flange contacts the oil tank opening, so that the compression of the rubber ring is constant at 1.8±0.1mm (compression rate 60%).

[0021] Furthermore, a metal skeleton 4 is embedded inside the sealing rubber ring 2. The metal skeleton 4 has an annular mesh structure. The cross-section of the metal skeleton 4 is "T" shaped, with its horizontal part embedded in the bottom of the rubber ring 2 and its vertical part extending to 2 / 3 of the height of the rubber ring 2.

[0022] The sealing rubber ring 2 described in this preferred embodiment is made of fluororubber (FKM) with a hardness of 70±5 Shore A. Its structure is a ring-shaped 316L stainless steel mesh with a mesh diameter of 1.5 mm and a wire diameter of 0.4 mm. The stainless steel mesh is vulcanized and encapsulated within the rubber. The skeleton cross-section is "T" shaped, with a horizontal width of 4 mm and a vertical height of 4.5 mm. The stainless steel mesh can effectively suppress the lateral expansion rate of the rubber. Comparative experiments showed that after soaking in fuel at 0°C for 240 h, the lateral expansion rate of the rubber was ≤3% (compared to 18% for the skeletonless control group).

[0023] Meanwhile, the upper surface of the bolt mounting hole of the metal flange 1 is provided with an annular groove, and an aluminum gasket 5 is placed in the groove. The aluminum gasket 5 is made of pure aluminum and has radial corrugations on its surface.

[0024] The aluminum gasket 5 described in this preferred embodiment is made of 1060 pure aluminum with a thickness of 1.3 mm. Its surface is provided with 8 radial corrugations with a corrugation depth of 0.2 mm. It is placed in an annular groove above the flange bolt hole. The groove is 1.0 mm deep and 8.5 mm in diameter. When the bolt is tightened, the aluminum gasket is compressed and plastic flow occurs: the corrugations are filled, and the aluminum material overflows and fills the gap between the bolt rod and the hole wall. After deformation, the outer diameter of the gasket expands and embeds into the side wall of the groove to form a mechanical interlock.

[0025] For highly corrosive environments, such as coastal areas, aluminum gasket 5 can be replaced with aluminum-zinc alloy gasket (Zn content 8wt%) to improve electrochemical compatibility; and a microporous silane coating with a thickness of 10μm can be added to the surface of the metal skeleton 4 to enhance adhesion to rubber and prevent corrosion and leakage at the sealing interface.

[0026] The specific assembly and implementation process is as follows:

[0027] Pre-assembly: Insert the sealing rubber ring 2 into the inside of the flange 1 of the metal flange, and attach the horizontal part of the skeleton to the bottom surface of the flange; embed the aluminum gasket 5 into the bolt hole groove, protruding 0.3mm from the surface of the groove.

[0028] Secure the assembly to the vehicle, placing the flange assembly at the fuel tank mounting port, with bolt 3 passing through the mounting hole; simultaneously tighten the bolts in two steps:

[0029] The first step involves applying a torque of 4 N·m to initially deform the aluminum pad and fill the gap.

[0030] The second step is to apply a torque of 10 N·m until the top surface of the flange contacts the oil tank opening (the limit is activated).

[0031] The effectiveness of the leak-proof flange structure was verified through the following sealing test in this embodiment:

[0032] Pressure test: Inject 0.05MPa air pressure into the oil tank and maintain the pressure for 5 minutes without leakage (industry standard 0.03MPa).

[0033] Vibration test: Apply velocity spectral density of 0.1 g² / Hz (20-2000 Hz) for 4 hours. No oil stains seeped out of the bolt holes.

[0034] The above-described embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Any modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A leak-proof flange structure for a motorcycle oil level sensor, suitable for two-hole cruiser models, comprising a metal flange (1), a sealing rubber ring (2), and mounting bolts (3), characterized in that: The metal flange (1) has an upwardly extending annular flange on its periphery, and the height of the annular flange is 1.5-2 times the thickness of the rubber ring (2) before compression. The sealing rubber ring (2) has a metal skeleton (4) embedded inside, which is a ring-shaped mesh structure; The upper surface of the bolt mounting hole of the metal flange (1) is provided with an annular groove, and an aluminum gasket (5) is placed in the groove. The thickness of the aluminum gasket (5) is 0.3-0.5 mm greater than the depth of the groove.

2. The leak-proof flange structure according to claim 1, characterized in that, The inner wall of the annular flange is clearance-fitted with the outer side of the sealing rubber ring (2), and the flange height is configured as a physical limiting structure when the bolt (3) is tightened.

3. The leakproof flange structure according to claim 1, characterized by, The cross-section of the metal frame (4) is "T" shaped, with its horizontal part embedded in the bottom of the rubber ring (2) and its vertical part extending to 2 / 3 of the height of the rubber ring (2).

4. The leakproof flange structure according to claim 1, characterized by, The aluminum gasket (5) is made of pure aluminum and has radial corrugations on its surface.

5. The leakproof flange structure according to claim 1, characterized by, The diameter of the annular groove is 1.5-2 mm larger than that of the bolt mounting hole, and the depth of the groove is 0.8-1.2 mm.

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