Fuel pump sealing structure

Abstract

The utility model discloses a sealing structure of a fuel pump. The sealing structure comprises an oil seal and an isobaric hole, the fuel pump shell is provided with a limiting face, the driving gear shaft is coaxially sleeved with the oil seal, and the inner end of the oil seal abuts against the limiting face. The oil seal is used for achieving sealing between the fuel pump shell and the driving gear shaft. The isobaric hole is a through hole and is formed in the fuel pump shell, one end of the isobaric hole is communicated with the fuel inlet, and the other end of the isobaric hole extends to the plane; the pressure of the oil seal is the same as that of the oil inlet, the sealing effect can be improved, and fuel oil leakage is prevented.

Description

Technical Field

[0001] The utility model belongs to the technical field of fuel pumps, and in particular relates to a fuel pump sealing structure. Background Art

[0002] See attached Figure 1 The fuel pump assembly is mainly composed of a fuel pump housing 101, a driving gear 102, a driven gear 103, a sleeve 104, an oil seal I 105 and a fuel pump spring 106.

[0003] See attached Figure 2 In the working state (the motor starts to drive the fuel pump assembly to work), the driving gear shaft drives the driving gear 102 to rotate at high speed and meshes with the passive gear 103 to generate a pressure difference, making the pressure at the oil inlet low (negative pressure) and the pressure at the oil outlet high. Diesel flows in from the oil inlet and flows out from the oil outlet. When the pressure at the oil outlet rises to the preset pressure value of the overflow valve, the overflow valve opens and overflow occurs. Among them, the oil seal I 105 is installed on the driving gear shaft to play a sealing role.

[0004] When the driving gear shaft rotates at high speed, a pressure difference will occur between the installation point of the oil seal Ⅰ105 and the oil inlet, that is, the pressure at the oil seal Ⅰ105 is greater than the pressure at the oil inlet, which affects the sealing performance of the oil seal Ⅰ105 and makes fuel leakage likely to occur.

[0005] In addition, the radial thickness of the connection between the sealing lip and the frame in the traditional oil seal Ⅰ105 is relatively thin, at 1.4mm to 1.6mm, so that when the internal pressure of the fuel pump assembly increases, the sealing lip is easily turned outward by the outward pressure, resulting in fuel leakage. Utility Model Content

[0006] In view of this, the utility model provides a fuel pump sealing structure, which makes the pressure at the oil seal the same as the pressure at the oil inlet, thereby improving the sealing effect and preventing fuel leakage.

[0007] The utility model is realized by the following technical solutions:

[0008] A fuel pump sealing structure, wherein a fuel pump housing is provided with an oil inlet, a driving gear is coaxially sleeved on a driving gear shaft, and the driving gear is located in the fuel pump housing; the fuel pump sealing structure comprises: an oil seal and an isobaric hole;

[0009] A limited surface is provided on the fuel pump housing, and the oil seal is coaxially sleeved on the driving gear shaft, with the inner end abutting against the limited surface; the oil seal is used to achieve sealing between the fuel pump housing and the driving gear shaft;

[0010] The isobaric hole is a through hole, which is arranged on the fuel pump housing, one end of which is connected with the fuel inlet, and the other end of which extends to the limit surface.

[0011] Furthermore, the oil seal is an oil seal II, and the oil seal II includes a frame, a spring, a sealing body and a sealing lip;

[0012] The skeleton is an annular structure with an inward annular edge at one end, and a sealing body is coated on the outside of the skeleton; the sealing lip is coaxially located in the skeleton, and one end is connected to the annular edge, and the other end is provided with a coaxial annular groove along the outer circumference; the sealing lip is coaxially sleeved on the outer circumference of the driving gear shaft; a spring is arranged in the annular groove to apply a radial inward force to the sealing lip.

[0013] Furthermore, the sealing lip is interference fit with the driving gear shaft.

[0014] Furthermore, the radial thickness of the connection between the sealing lip and the annular edge is 1.9 mm to 2.1 mm.

[0015] Furthermore, the isobaric hole is a circular hole.

[0016] Furthermore, the diameter of the circular hole is 2 mm.

[0017] Beneficial effects:

[0018] (1) The utility model provides a fuel pump sealing structure, in which an isobaric hole is arranged on the fuel pump housing, one end of the isobaric hole is connected to the oil inlet, and the other end extends to be connected to the position where the oil seal is installed, so that the pressure at the oil seal is the same as the pressure at the oil inlet, which can improve the sealing effect and prevent fuel leakage.

[0019] (2) The oil seal II provided by the utility model has a sealing lip coaxially sleeved on the outer circumference of the driving gear shaft; a spring is arranged in the annular groove to apply a radial inward force to the sealing lip to ensure the sealing effect of the oil seal II.

[0020] (3) The sealing lip of the utility model is interference fit with the driving gear shaft, further ensuring the sealing effect of the oil seal II.

[0021] (4) The radial thickness of the connection between the sealing lip and the annular edge of the utility model is 1.9 mm to 2.1 mm, which can improve the rigidity of the sealing lip and prevent the sealing lip from being turned outward due to the increased liquid pressure inside the fuel pump, thereby preventing fuel leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of a fuel pump assembly in the prior art;

[0023] Figure 2 It is a schematic diagram of the fuel pump oil circuit in the prior art;

[0024] Figure 3 This is the fuel pump sealing structure of the utility model;

[0025] Figure 4 This is the structural diagram of the oil seal of the utility model;

[0026] Among them, 101-fuel pump housing, 102-driving gear, 103-driven gear, 104-shaft sleeve, 105-oil seal I, 106-oil pump spring, 107-oil inlet, 108-oil outlet;

[0027] 1-isopressure hole, 2-skeleton, 3-spring, 4-sealing body, 5-sealing lip, 6-oil seal II, 7-limiting surface. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0029] This embodiment provides a fuel pump sealing structure. Figure 1 and 3 The fuel pump housing 101 is provided with a fuel inlet; the driving gear 102 is coaxially sleeved on the driving gear shaft, and the driving gear 102 is located in the fuel pump housing 101;

[0030] The fuel pump sealing structure comprises: an oil seal and an isobaric hole 1;

[0031] The fuel pump housing 101 is provided with a limited surface 7, and the oil seal is coaxially sleeved on the driving gear shaft, with the inner end abutting against the limited surface 7; the oil seal is used to achieve sealing between the fuel pump housing 101 and the driving gear shaft;

[0032] The isobaric hole 1 is a through hole, which is arranged on the fuel pump housing 101, one end of which is connected to the fuel inlet, and the other end of which extends to the limit surface 7. In a specific embodiment, the isobaric hole 1 is a circular hole with a diameter of 2 mm.

[0033] See attached Figure 4 , the oil seal is an oil seal II 6, and the oil seal II 6 comprises a skeleton 2, a spring 3, a sealing body 4 and a sealing lip 5;

[0034] The skeleton 2 is an annular structure with an inward annular edge at one end, and the skeleton 2 is covered with a sealing body 4; the sealing lip 5 is coaxially located in the skeleton 2, and one end is connected to the annular edge, and the other end is provided with a coaxial annular groove along the outer circumferential surface; the sealing lip 5 is coaxially sleeved on the outer circumference of the driving gear shaft, and has an interference fit with the driving gear shaft; the radial thickness of the connection between the sealing lip 5 and the annular edge is 1.9mm~2.1mm, and is 2mm in the specific embodiment, which can improve the rigidity of the sealing lip 5 and prevent the sealing lip 5 from being turned outward due to the outward pressure caused by the increase of the internal liquid pressure of the fuel pump, resulting in fuel leakage.

[0035] The spring 3 is arranged in the annular groove to apply a radially inward force to the sealing lip, thereby further ensuring the seal between the sealing lip and the driving gear shaft;

[0036] In a specific embodiment, the sealing body 4 and the sealing lip 5 are formed in one piece.

[0037] Working principle:

[0038] When not in operation (i.e. the fuel pump assembly is not working), the active and passive gear shafts are stationary. When the oil circuit generates pressure due to the electric pump or the hand pump, the pressure inside the fuel pump assembly is equal. When the pressure rises to reach the preset pressure value of the relief valve (1.0MPa~1.2MPa), the relief valve opens to generate overflow. During the entire pressure-injection process, due to the existence of the isobaric hole 1, the position pressure of the oil seal II 6 is the same as the pressure inside the fuel pump assembly, which can improve the sealing effect and prevent fuel leakage.

[0039] When in working state (i.e. when the motor starts to drive the driving gear shaft to rotate, thereby driving the fuel pump assembly to work), due to the existence of the isobaric hole 1, the pressure at the oil seal position is consistent with the pressure at the oil inlet 107, which can ensure the sealing requirements of the oil seal II6 under the condition of high-speed rotation (8000r / min) of the driving gear shaft.

[0040] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fuel pump sealing structure, wherein a fuel inlet is provided on a fuel pump housing, a driving gear is coaxially sleeved on a driving gear shaft, and the driving gear is located in the fuel pump housing; characterized in that: The fuel pump sealing structure comprises: an oil seal and an isobaric hole; A limited surface is provided on the fuel pump housing, and the oil seal is coaxially sleeved on the driving gear shaft, with the inner end abutting against the limited surface; the oil seal is used to achieve sealing between the fuel pump housing and the driving gear shaft; The isobaric hole is a through hole, which is arranged on the fuel pump housing, one end of which is connected with the fuel inlet, and the other end of which extends to the limit surface.

2. A fuel pump sealing structure as claimed in claim 1, characterized in that: The oil seal is an oil seal II, which includes a frame, a spring, a sealing body and a sealing lip; The skeleton is an annular structure with an inward annular edge at one end, and a sealing body is coated on the outside of the skeleton; the sealing lip is coaxially located in the skeleton, and one end is connected to the annular edge, and the other end is provided with a coaxial annular groove along the outer circumference; the sealing lip is coaxially sleeved on the outer circumference of the driving gear shaft; a spring is arranged in the annular groove to apply a radial inward force to the sealing lip.

3. A fuel pump sealing structure as claimed in claim 2, characterized in that: The sealing lip is interference fit with the driving gear shaft.

4. A fuel pump sealing structure as claimed in claim 2, characterized in that: The radial thickness of the connection between the sealing lip and the annular edge is 1.9 mm to 2.1 mm.

5. A fuel pump sealing structure according to any one of claims 1 to 4, characterized in that: The isobaric hole is a circular hole.

6. A fuel pump sealing structure as claimed in claim 5, characterized in that: The diameter of the circular hole is 2 mm.

Images