Split type high-pressure fuel feed pump plunger pair

Abstract

The utility model belongs to the technical field of high-pressure common-rail oil feed pumps, and particularly relates to a split type high-pressure oil feed pump plunger pair which comprises a plunger pair and a soft metal washer, a sinking groove is formed in the top of the plunger pair, the soft metal washer is installed in the sinking groove and exposed out of the sinking groove, and when the plunger pair is installed on a pump cover, the soft metal washer is arranged in the sinking groove. And the soft metal gasket deforms and is in contact with the pump cover. After assembly, the sealing face of the soft metal gasket and the pump cover is an annular high-pressure sealing ring, high-pressure fuel sealing is achieved, the contact area of the soft metal gasket and the pump cover is reduced, generation of holes is reduced, and therefore the oil supply capacity of the oil pump is stabilized, and oil leakage is effectively prevented. Due to the fact that the soft metal gasket has elasticity, irreversible damage such as scratching, bumping and deformation caused by the plunger pair to the sealing plane of the pump cover is reduced, and the service life of the pump cover and the service life of the plunger pair are prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of high-pressure common rail fuel supply pumps, and particularly relates to a split-type high-pressure common rail fuel supply pump plunger pair. Background Art

[0002] Under the increasingly strict emission regulations, the high-pressure common rail fuel injection system usually optimizes the in-cylinder combustion of the engine by increasing the injection pressure to achieve the goal of reducing harmful substance emissions. In order to meet the high common rail pressure, the core component plunger pair of the high-pressure common rail fuel supply pump needs to reliably supply high-pressure fuel. Among them, for the high-pressure common rail fuel supply pump assembly with a pump cover structure, the sealing stability and reliability between the top surface of the plunger pair and the pump cover affect the supply of high-pressure fuel.

[0003] In the prior art, for the high-pressure common rail fuel supply pump with a pump cover structure, the installation and connection method of the two components of the plunger pair and the pump cover generally adopts a threaded connection structure, and a large-plane high-pressure hard seal contact is adopted between the high-pressure oil outlet top of the plunger pair and the sealing surface of the pump cover. Under the action of the specified torque, the two sealing planes are closely attached to achieve the sealing of high-pressure fuel. However, when choosing the large-plane hard seal scheme, the following problems exist:

[0004] 1. The large-plane seal results in a relatively large contact area, and it is inevitable that cavitation occurs in the high-pressure plane hard seal structure between the plunger pair and the pump cover due to high pressure. Once cavitation forms, it will seriously affect the fuel supply capacity of the fuel supply pump. The leakage of high-pressure fuel at this position will return to the fuel tank along the return oil pipeline, causing the fuel temperature to rise rapidly, resulting in engine alarms or even shutdowns;

[0005] 2. As a vulnerable part, the plunger pair needs to be disassembled and replaced relatively frequently. During the repeated disassembly and assembly of the plunger pair, irreversible damage such as scratches, bumps, and deformation will be caused to the original sealing plane. The pump cover has a short service life and a high replacement cost. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a split-type high-pressure common rail fuel supply pump plunger pair, which not only realizes the sealing of high-pressure fuel, but also reduces the contact area with the pump cover, thereby reducing cavitation, stabilizing the fuel supply capacity of the fuel pump, and effectively preventing oil leakage; moreover, it reduces the irreversible damage such as scratches, bumps, and deformation caused by the soft metal gasket to the sealing plane of the pump cover, extends the service life of the pump cover and the plunger pair, and improves the sealing stability and reliability between the top surface of the plunger pair and the pump cover.

[0007] The purpose of the utility model is realized by such a technical solution. A split-type high-pressure common rail fuel supply pump plunger pair includes: a plunger pair and a soft metal gasket. A sink is provided at the top of the plunger pair, and the soft metal gasket is installed in the sink. The soft metal gasket is exposed outside the sink. When the plunger pair is installed on the pump cover, the soft metal gasket deforms and contacts the pump cover.

[0008] The plunger pair and the soft metal washer are separately arranged. The sealing contact surface between the plunger pair and the pump cover is optimized from the commonly used large-plane high-pressure hard-sealing structure to the small-annular-zone seal between the soft metal washer and the pump cover, so that the plane of the plunger pair no longer directly contacts the pump cover's sealing plane to seal the high-pressure fuel. When the plunger pair is tightened to the pump cover by threads under a specified torque, the soft metal washer deforms to a certain extent under the action of the torque. The soft metal washer and the large sealing plane on the pump cover form an annular high-pressure sealing band, which not only realizes the high-pressure fuel sealing, but also reduces the contact area, thereby reducing cavitation, stabilizing the fuel supply capacity of the oil pump, and effectively preventing oil leakage. Due to the elasticity of the soft metal washer, the plunger pair deforms during the assembly or disassembly process, effectively solving the irreversible damage such as scratching, bumping, and deformation of the pump cover's sealing plane caused by the plunger pair, extending the service life of the pump cover and the plunger pair, and at the same time reducing the processing precision, the difficulty and cost of disassembly, installation and maintenance of the plunger pair and the pump cover, making the plunger pair structure have better economy.

[0009] Preferably, the soft metal washer includes a corrugated metal layer and a soft sealing layer, and the soft sealing layer is coated on the outside of the corrugated metal layer.

[0010] Preferably, the material of the corrugated metal layer is stainless steel, nitinol or iron; the material of the soft sealing layer is polytetrafluoroethylene or rubber.

[0011] Preferably, the material of the soft metal washer is aluminum alloy.

[0012] Preferably, the soft metal washer and the sunk groove are connected by interference fit.

[0013] Preferably, the two end faces of the soft metal washer are arc-shaped curved top surfaces, and the shape of the sunk groove matches that of the soft metal washer.

[0014] Due to the adoption of the above technical solutions, the utility model has the following advantages:

[0015] 1. The plunger pair and the soft metal washer are separately arranged, avoiding direct contact between the plunger pair and the pump cover, and having a small-annular-zone seal contact between the soft metal washer and the pump cover; not only realizing the high-pressure fuel sealing, but also reducing the contact area, thereby reducing the generation of cavitation, stabilizing the fuel supply capacity of the oil pump, and effectively preventing oil leakage;

[0016] 2. Due to the elasticity of the soft metal washer, the soft metal washer deforms during the assembly or disassembly process of the plunger pair, effectively reducing the irreversible damage such as scratching, bumping, and deformation of the pump cover's sealing plane caused by the plunger pair, and extending the service life of the pump cover and the plunger pair;

[0017] 3. The soft metal gasket is installed on the plunger pair, reducing the machining precision of the plunger pair and the pump cover and the difficulty of disassembly, repair and maintenance, making the plunger pair structure have better economy. Brief Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn to actual scale.

[0019] Figure 1 It is a schematic structural diagram of a split high-pressure fuel supply pump plunger pair of the present invention;

[0020] Figure 2 It is a schematic structural diagram of the soft metal gasket.

[0021] Reference Signs:

[0022] 1 - plunger pair, 11 - sinking groove, 2 - soft metal gasket, 21 - corrugated metal layer, 22 - soft sealing layer, 3 - pump cover. Specific Embodiments

[0023] Please refer to Figure 1 , a split high-pressure fuel supply pump plunger pair, comprising: a plunger pair 1 and a soft metal gasket 2. A sinking groove 11 is provided at the top of the plunger pair 1. The soft metal gasket 2 is installed in the sinking groove 11. The soft metal gasket 2 is exposed outside the plunger pair 1. When the plunger pair 1 is installed on the pump cover 3, the soft metal gasket 2 deforms and contacts the pump cover 3.

[0024] A sinking groove 11 for installing the soft metal gasket 2 is provided at the top of the plunger pair 1, and the soft metal gasket 2 is installed in the sinking groove 11. The plunger pair 1 and the soft metal gasket 2 are separated, thus obtaining a split plunger pair structure. The sealing contact surface between the plunger pair 1 and the pump cover 3 is optimized from the generally adopted large-plane high-pressure hard-sealing structure to the small-annular-zone high-pressure seal between the soft metal gasket 2 and the pump cover 3, so that the plane of the plunger pair 1 no longer directly contacts the sealing plane of the pump cover 3 to seal the high-pressure fuel. When the plunger pair 1 is tightened to the pump cover 3 by thread under the action of a specified torque, the soft metal gasket 2 deforms to a certain extent under the action of the torque. The soft metal gasket 2 and the large sealing plane on the pump cover 3 form an annular high-pressure sealing belt, which not only realizes the high-pressure fuel sealing, but also reduces the contact area, thereby reducing the generation of cavities, stabilizing the fuel supply capacity of the oil pump, and effectively preventing oil leakage. Because the soft metal gasket 2 has elasticity, the plunger pair 1 deforms during the assembly or disassembly process, effectively reducing the irreversible damage such as scratching, bumping, and deformation to the sealing plane of the pump cover 3 caused by the plunger pair 1, prolonging the service life of the pump cover 3 and the plunger pair 1, and at the same time reducing the machining precision of the plunger pair 1 and the pump cover 3, the difficulty and cost of disassembly, repair and maintenance, making the plunger pair structure have better economy.

[0025] Embodiment 1

[0026] Please refer to Figure 2 , further, the soft metal gasket 2 includes a corrugated metal layer 21 and a soft sealing layer 22, and the soft sealing layer 22 is coated on the outer side of the corrugated metal layer 21. Specifically, the soft metal gasket 2 adopts a metal tube bundle corrugated composite gasket in the prior art, which is wound into a coaxial corrugated shape with a thin metal tube. The thin metal tube forms a corrugated shape to provide mechanical support, and a soft sealing layer 22 is covered on the outer layer of the thin metal tube, so that the metal corrugated composite gasket has better compression and rebound performance and sealing performance. By utilizing the sealing property of the soft sealing layer 22 and the advantages of the strength and elasticity of the metal, when the plunger pair 1 is assembled, the soft metal gasket 2 at the top thereof is deformed to a certain extent under the action of torque, and forms an annular high-pressure sealing belt with the large sealing plane on the pump cover 3, realizing high-pressure fuel sealing.

[0027] Preferably, the material of the corrugated metal layer 21 includes but is not limited to stainless steel, nickel-titanium alloy or iron; the material of the soft sealing layer 22 includes but is not limited to polytetrafluoroethylene or rubber. The rubber adopts a material resistant to high pressure and high temperature.

[0028] Please refer to Figure 1 , further, the soft metal gasket 2 and the sink 11 are connected by interference fit. Specifically, the outer diameter of the soft metal gasket 2 is larger than the size of the sink 11. By utilizing the elasticity of the soft metal gasket 2, the soft metal gasket 2 is installed in the sink 11 under pressure, and the soft metal gasket 2 is not easy to fall off from the sink 11.

[0029] Please refer to Figure 1 and Figure 2 , further, the two end faces of the soft metal gasket 2 are arc-shaped curved top surfaces, and the shape of the sink 11 matches that of the soft metal gasket 2. One of the arc-shaped curved top surfaces is in fit with the plane of the sink 11 during installation, and the other arc-shaped curved top surface is in fit with the sealing plane of the pump cover 3. The soft metal gasket 2 is deformed under the action of the installation pre-tightening force, and the formed sealing ring belt can ensure a high degree of fit between the two sealing planes, ensuring the connection stability and reliability of the high-pressure sealing surface between the plunger pair 1 and the pump cover 3.

[0030] Embodiment 2

[0031] Please refer to Figure 1 , the specific implementation manner of this embodiment is basically the same as that of Embodiment 1, and the difference lies in that: the soft metal gasket 2 is made of aluminum alloy. The aluminum alloy has a lower hardness than the pump cover 3 and the plunger pair 1, and is deformed under the action of the installation pre-tightening force. Not only can the formed sealing ring belt ensure a high degree of fit between the two sealing planes. Moreover, it reduces irreversible damage such as scratches, bumps, and deformations to the sealing plane of the pump cover 3.

[0032] In the present utility model, the plunger pair 1 and the soft metal gasket 2 are separably arranged, avoiding direct contact between the plunger pair 1 and the pump cover 3, and having a small annular belt sealing contact between the soft metal gasket 2 and the pump cover 3. It not only realizes high-pressure fuel sealing, but also reduces the contact area, thereby reducing the generation of cavitation, stabilizing the fuel supply capacity of the oil pump, and effectively preventing oil leakage. Since the soft metal gasket 2 has elasticity, the plunger pair 1 deforms during the assembly or disassembly process, effectively reducing irreversible damage such as scratches, bumps, and deformation to the sealing plane of the pump cover 3 by the plunger pair 1, prolonging the service life of the pump cover 3 and the plunger pair 1, while reducing the processing precision of the plunger pair 1 and the pump cover 3 and the difficulty of disassembly, installation and maintenance, making the plunger pair structure have better economy.

Claims

1. A split high-pressure oil supply pump plunger pair, characterized in that: include: A plunger pair (1) and a soft metal gasket (2); a sink groove (11) is provided on the top of the plunger pair (1); the soft metal gasket (2) is installed in the sink groove (11); the soft metal gasket (2) is exposed outside the sink groove (11); when the plunger pair (1) is installed on a pump cover (3), the soft metal gasket (2) is deformed and contacts the pump cover (3).

2. The split high-pressure oil supply pump plunger pair according to claim 1, characterized in that: The soft metal gasket (2) comprises a corrugated metal layer (21) and a soft sealing layer (22), wherein the soft sealing layer (22) is coated on the outer side of the corrugated metal layer (21).

3. The split high-pressure oil supply pump plunger pair according to claim 1 or 2, characterized in that: The material of the corrugated metal layer (21) is stainless steel, nickel-titanium alloy or iron; the material of the soft sealing layer (22) is polytetrafluoroethylene or rubber.

4. The split high-pressure oil supply pump plunger pair according to claim 1, characterized in that: The material of the soft metal washer (2) is aluminum alloy.

5. The split high-pressure oil supply pump plunger pair according to claim 1, 2 or 4, characterized in that: The soft metal gasket (2) is connected to the sink (11) through interference fit.

6. The split high-pressure oil supply pump plunger pair according to claim 3, characterized in that: The soft metal gasket (2) is connected to the sink (11) through interference fit.

7. The split high-pressure oil supply pump plunger pair according to claim 1, 2, 4 or 6, characterized in that: The two end faces of the soft metal gasket (2) are arc-shaped top faces, and the shape of the sink groove (11) matches the soft metal gasket (2).

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