Needle valve gap limiting structure and fuel injector

Abstract

The application belongs to the technical field of engine components, and discloses a needle valve gap limiting structure and an oil sprayer. The needle valve gap limiting structure comprises a valve body, a needle valve, a buffer assembly and an iron core. The needle valve is located in the valve body, the buffer assembly is arranged in the valve body, the iron core is arranged above the buffer assembly along the axial direction of the needle valve, the lower end surface of the iron core abuts against the buffer assembly, the iron core is provided with a limiting boss, the limiting boss is welded with the end surface of the valve body, and the iron core is fixedly connected with the valve body through the welding process. The limitation of the press-fitting process is solved, the cost of introducing a precision press-fitting device is greatly reduced, the outer peripheral surface of the iron core is mechanically processed to form a limiting boss, the distance from the lower end surface of the limiting boss to the bottom end surface of the iron core is provided with multiple size grades, so that the gap of the needle valve can be ensured not to deviate through the limiting boss in the welding process. Meanwhile, the tolerance accumulation caused by the assembly of the valve body and the needle valve can be offset, the welding process is more stable, and the dynamic flow consistency of the oil sprayer is improved.

Description

Technical Field

[0001] This invention relates to the field of engine component technology, and in particular to a needle valve gap limiting structure and a fuel injector. Background Technology

[0002] As one of the key components of the internal combustion engine's fuel supply system, the performance of the fuel injector will be greatly affected by its proper functioning. The fuel injector works by controlling a precision assembly, which consists of a needle valve and a needle valve body.

[0003] The cylindrical iron core is fixedly mounted on the valve body using an interference fit process, achieving consistent needle valve lift through a process of pressing and testing simultaneously. However, the pressing process requires high equipment stability and precision, necessitates significant investment in pressing equipment, and incurs high maintenance costs. Furthermore, the needle valve clearance is extremely precise; any change in the position of the iron core relative to the valve body, or core misalignment, makes it difficult to control the needle valve lift accuracy, resulting in poor consistency and preventing precise injector spraying.

[0004] Therefore, there is an urgent need for a needle valve gap limiting structure and an injector to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a needle valve gap limiting structure, which solves the limitations of the press-fitting process, significantly reduces the cost of introducing precision press-fitting equipment, and at the same time ensures that the needle valve gap does not shift, can offset the cumulative tolerance caused by the assembly of the valve body and needle valve, makes the welding process more stable, and improves the dynamic flow consistency of the injector.

[0006] To address the aforementioned problems in the existing technology, the present invention adopts the following technical solution:

[0007] The needle valve gap limiting structure includes:

[0008] Valve body;

[0009] A needle valve, wherein the needle valve is located within the valve body;

[0010] A buffer assembly is disposed within the valve body and sleeved on the needle valve;

[0011] An iron core is disposed above the buffer assembly along the axial direction of the needle valve. The lower end face of the iron core abuts against the buffer assembly. The iron core is provided with a limiting boss, which is welded to the end face of the valve body.

[0012] Preferably, the limiting boss has a ring-shaped structure along the circumferential direction of the iron core.

[0013] Preferably, the limiting boss is integrally formed with the iron core.

[0014] Preferably, the needle valve gap limiting structure further includes a positioning sleeve, which is located inside the iron core. The outer ring of the positioning sleeve is slidably connected to the inner circumferential wall of the iron core, and the inner ring of the positioning sleeve is fixedly connected to the needle valve.

[0015] Preferably, the buffer assembly includes an intermediate block and a buffer spring. The outer ring of the intermediate block is spaced apart from the valve body, the inner ring of the intermediate block abuts against the outer peripheral surface of the needle valve, the buffer spring is embedded in the intermediate block, and one end of the buffer spring abuts against the positioning sleeve.

[0016] Preferably, the needle valve gap limiting structure further includes a base, which is located below the buffer assembly, is sleeved on the needle valve, and abuts against the intermediate block.

[0017] Preferably, the needle valve gap limiting structure further includes a return spring, which is disposed inside the iron core and sleeved on the needle valve. One end of the return spring abuts against the positioning sleeve. When the needle valve blocks the oil outlet of the valve body, the return spring is in a compressed state.

[0018] Preferably, the needle valve gap limiting structure further includes an electromagnet, which is disposed on the valve body and sleeved on the iron core. When the electromagnet is energized, the electromagnet and the iron core are magnetically attracted, and the needle valve moves toward the return spring so that the needle valve opens the oil outlet of the valve body.

[0019] Preferably, along the circumferential direction of the iron core, the outer peripheral wall of the limiting boss is spaced apart from the inner sidewall of the electromagnet.

[0020] To achieve the above objectives, the present invention also provides an injector including the aforementioned needle valve gap limiting structure, wherein the needle valve gap limiting structure is used to limit the needle valve gap offset of the injector.

[0021] The beneficial effects of this invention are as follows:

[0022] The needle valve gap limiting structure provided by this invention includes a needle valve located within a valve body, a buffer assembly housed within the valve body, and a core positioned above the buffer assembly. Along the axial direction of the needle valve, the lower end face of the core abuts against the buffer assembly. A limiting boss protrudes from the core and is welded to the end face of the valve body. The needle valve sequentially passes through the inner cavity of the core, the buffer assembly, and the inner cavity of the valve body. The core is fixedly connected to the valve body via welding, overcoming the limitations of press-fitting processes and significantly reducing the cost of importing precision press-fitting equipment. The outer circumferential surface of the core is machined with a limiting boss. The distance from the lower end face of the limiting boss to the bottom end face of the core is available in various dimensional grades, ensuring that the needle valve gap does not shift during welding. Simultaneously, it offsets the cumulative tolerances caused by the assembly of the valve body and needle valve, resulting in a more stable welding process and improved dynamic flow consistency of the injector.

[0023] The injector provided by this invention includes a needle valve gap limiting structure to restrict needle valve gap offset. The distance from the lower end face of the limiting boss to the bottom end face of the iron core is set in various dimensional grades, ensuring that the needle valve gap does not shift during welding. Simultaneously, it can offset the cumulative tolerances caused by the assembly of the valve body and needle valve, resulting in a more stable welding process. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of the needle valve gap limiting structure in an embodiment of the present invention.

[0025] Figure label:

[0026] 1. Valve body; 2. Needle valve; 3. Iron core; 4. Limiting boss; 5. Positioning sleeve; 6. Intermediate block; 7. Buffer spring; 8. Base; 9. Return spring; 10. Electromagnet. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0028] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0031] The fuel injector operates by controlling a precision assembly, which consists of a needle valve and a needle valve body. An interference fit process is used to fix a cylindrical iron core onto the valve body, achieving consistent needle valve lift through a process of pressing and testing. However, the pressing process requires high equipment stability and precision, necessitates significant investment in pressing equipment, and incurs high maintenance costs. Furthermore, the needle valve clearance is extremely precise; any change in the position of the iron core relative to the valve body causes core misalignment, making needle valve lift accuracy control difficult and resulting in poor consistency, ultimately hindering precise fuel injection. To address this, this embodiment provides a needle valve clearance limiting structure, overcoming the limitations of the pressing process, significantly reducing the cost of introducing precision pressing equipment, ensuring the needle valve clearance does not shift, offsetting the accumulated tolerances from the valve body and needle valve assembly, improving welding stability, and enhancing the dynamic flow consistency of the fuel injector.

[0032] like Figure 1As shown, in this embodiment, the needle valve gap limiting structure includes a valve body 1, a needle valve 2, a buffer assembly, and an iron core 3. The needle valve 2 is located inside the valve body 1, the buffer assembly is disposed inside the valve body 1 and sleeved on the needle valve 2, and the iron core 3 is positioned above the buffer assembly. Along the axial direction of the needle valve 2, the lower end face of the iron core 3 abuts against the buffer assembly, and the iron core 3 has a protruding limiting boss 4, which is welded to the end face of the valve body 1. Specifically, the needle valve 2 is slidably disposed within the inner cavity of the valve body 1. Along the circumferential direction of the needle valve 2, the inner ring of the buffer assembly abuts against the outer circumferential surface of the needle valve 2, and the outer ring of the buffer assembly abuts against the inner sidewall of the needle valve 2. The needle valve 2 sequentially passes through the inner cavity of the iron core 3, the buffer assembly, and the inner cavity of the valve body 1. The iron core 3 is located above the buffer assembly, and a portion of the iron core 3 is inserted into the inner cavity of the valve body 1. Furthermore, the iron core 3 is fixedly connected to the valve body 1 through a welding process, overcoming the limitations of the press-fitting process and significantly reducing the cost of introducing precision press-fitting equipment. The outer circumferential surface of the iron core 3 is machined with a limiting boss 4. The distance from the lower end face of the limiting boss 4 to the bottom end face of the iron core 3 is available in various dimensional grades. This ensures that the gap of the needle valve 2 does not shift during welding. The step height of the iron core 3 is graded, with 20 different grades and a thickness of 0.01mm. For stroke control, a selection method is used to ensure the stroke of the needle valve 2 is 0.2mm. During the assembly of the needle valve 2 and the valve body 1, the distance from the end face of the iron core 3 to the end face of the valve body 1 is measured first, and then the step height of the iron core 3 is selected. Simultaneously, this offsets the cumulative tolerances caused by the assembly of the valve body 1 and the needle valve 2, keeping the needle valve gap tolerance within ±0.15mm. This results in a more stable welding process, significantly reduced scrap rate, and improved dynamic flow consistency of the injector.

[0033] Furthermore, continue to refer to Figure 1 Along the circumference of the iron core 3, the limiting boss 4 has a ring-shaped structure. Specifically, the limiting boss 4 and the iron core 3 are integrally formed by machining, casting or other methods. On the outer circumference of the iron core 3, the limiting boss 4 forms a ring around the iron core 3 and is welded and fixed to the end face of the valve body 1, so that the welding offset is limited during welding, which can ensure the lift accuracy of the needle valve 2.

[0034] Furthermore, continue to refer to Figure 1 The needle valve gap limiting structure also includes a positioning sleeve 5, which is located inside the iron core 3. The outer ring of the positioning sleeve 5 is slidably connected to the inner circumferential wall of the iron core 3, and the inner ring of the positioning sleeve 5 is fixedly connected to the needle valve 2. Specifically, the positioning sleeve 5 is sleeved on the needle valve 2, and the positioning sleeve 5 and the needle valve 2 are in sliding fit. During the process of the needle valve 2 sliding up and down relative to the valve body 1, the positioning sleeve 5 can ensure that the needle valve 2 always slides along the axial direction without deviation, ensuring that the lift accuracy of the needle valve 2 and the needle valve gap are within the tolerance range.

[0035] Furthermore, continue to refer to Figure 1The buffer assembly includes an intermediate block 6 and a buffer spring 7. The outer ring of the intermediate block 6 is spaced apart from the valve body 1, and the inner ring of the intermediate block 6 abuts against the outer circumferential surface of the needle valve 2. The buffer spring 7 is embedded in the intermediate block 6, and one end of the buffer spring 7 is pressed against the positioning sleeve 5. Specifically, the intermediate block 6 is located in the inner cavity of the valve body 1, one end of the buffer spring 7 is fixedly connected to the intermediate block 6, and the other end is pressed against the positioning sleeve 5. During the process of the needle valve 2 closing the oil outlet of the valve body 1, the buffer spring 7 plays a buffering role, ensuring high lift accuracy of the needle valve 2 and extending the service life of the needle valve 2.

[0036] Furthermore, continue to refer to Figure 1 The needle valve gap limiting structure also includes a base 8, which is located below the buffer assembly. The base 8 is sleeved on the needle valve 2 and abuts against the intermediate block 6. Specifically, the base 8 supports the buffer assembly. The needle valve 2 is sequentially inserted through the positioning sleeve 5, the intermediate block 6, the base 8, and the valve body 1. During the power-on and power-off process, the needle valve 2 slides along the axial direction to open or close the oil outlet of the valve body 1, thereby performing oil injection and oil cut-off.

[0037] Furthermore, continue to refer to Figure 1 The needle valve gap limiting structure also includes a return spring 9, which is located inside the iron core 3 and sleeved on the needle valve 2. One end of the return spring 9 is pressed against the positioning sleeve 5. When the needle valve 2 blocks the oil outlet of the valve body 1, the return spring 9 is in a compressed state. Specifically, one end of the return spring 9 is fixedly connected to the upper seat component, and the other end is pressed against the upper end face of the positioning sleeve 5. When the needle valve 2 slides with the valve body 1 and slides upward along the axial direction, the needle valve 2 opens the oil outlet of the valve body 1, and the return spring 9 is continuously compressed and always in a compressed state. When the power is off, the needle valve 2 slides downward under the fuel pressure and the elastic action of the return spring 9 to block the oil outlet of the valve body 1.

[0038] Furthermore, continue to refer to Figure 1 The needle valve gap limiting structure also includes an electromagnet 10, which is mounted on the valve body 1 and sleeved on the iron core 3. When the electromagnet 10 is energized, it magnetically attracts the iron core 3, causing the needle valve 2 to move closer to the return spring 9, thus opening the oil outlet of the valve body 1. When the electromagnet 10 is de-energized, the needle valve 2 slides downward under the pressure of fuel and the elasticity of the return spring 9, blocking the oil outlet of the valve body 1 and preventing the injector from supplying fuel.

[0039] Furthermore, continue to refer to Figure 1Along the circumferential direction of the iron core 3, the outer peripheral wall of the limiting boss 4 is spaced apart from the inner side wall of the electromagnet 10. Specifically, the limiting boss 4 is fixed to the upper end face of the valve body 1. Under the limiting action of the limiting boss 4, the iron core 3 plays a limiting role relative to the valve body 1 in the horizontal and vertical directions, ensuring that the needle valve gap does not shift and can offset the cumulative tolerance caused by the assembly of the valve body 1 and the needle valve 2.

[0040] This embodiment also provides a fuel injector, including the aforementioned needle valve gap limiting structure, which is used to limit the needle valve gap offset of the fuel injector. Specifically, the distance from the lower end face of the limiting boss 4 to the bottom end face of the iron core 3 is set in multiple size grades, so that the gap of the needle valve 2 can be ensured not to shift during the welding process by the limiting boss 4. At the same time, it can offset the cumulative tolerance caused by the assembly of the valve body 1 and the needle valve 2, making the welding process more stable, greatly reducing the scrap rate, and thus improving the dynamic flow consistency of the fuel injector.

[0041] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, re-limitations, and substitutions without departing from the protection scope of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A needle valve gap limiting structure, characterized in that, include: Valve body (1); Needle valve (2), the needle valve (2) is located inside the valve body (1); A buffer assembly is disposed inside the valve body (1) and sleeved on the needle valve (2). The iron core (3) is located above the buffer assembly and along the axial direction of the needle valve (2). The lower end face of the iron core (3) abuts against the buffer assembly. The iron core (3) is provided with a limiting boss (4). The limiting boss (4) is welded to the end face of the valve body (1). The distance from the lower end face of the limiting boss (4) to the bottom end face of the iron core (3) is set in multiple size grades. During the welding process, the limiting boss (4) can ensure that the gap of the needle valve (2) does not shift. The step height of the iron core (3) is graded. When controlling the lift, the selection method is used to ensure the lift size of the needle valve (2).

2. The needle valve gap limiting structure according to claim 1, characterized in that, Along the circumferential direction of the iron core (3), the limiting boss (4) has a ring-shaped structure.

3. The needle valve gap limiting structure according to claim 1, characterized in that, The limiting boss (4) is integrally formed with the iron core (3).

4. The needle valve gap limiting structure according to claim 1, characterized in that, The needle valve gap limiting structure also includes a positioning sleeve (5), which is located inside the iron core (3). The outer ring of the positioning sleeve (5) is slidably connected to the inner circumferential wall of the iron core (3), and the inner ring of the positioning sleeve (5) is fixedly connected to the needle valve (2).

5. The needle valve gap limiting structure according to claim 4, characterized in that, The buffer assembly includes an intermediate block (6) and a buffer spring (7). The outer ring of the intermediate block (6) is spaced apart from the valve body (1), and the inner ring of the intermediate block (6) abuts against the outer circumferential surface of the needle valve (2). The buffer spring (7) is embedded in the intermediate block (6), and one end of the buffer spring (7) abuts against the positioning sleeve (5).

6. The needle valve gap limiting structure according to claim 5, characterized in that, The needle valve gap limiting structure also includes a base (8), which is located below the buffer assembly. The base (8) is sleeved on the needle valve (2) and abuts against the intermediate block (6).

7. The needle valve gap limiting structure according to claim 4, characterized in that, The needle valve gap limiting structure also includes a return spring (9), which is located inside the iron core (3). The return spring (9) is sleeved on the needle valve (2), and one end of the return spring (9) is pressed against the positioning sleeve (5). When the needle valve (2) blocks the oil outlet of the valve body (1), the return spring (9) is in a compressed state.

8. The needle valve gap limiting structure according to claim 7, characterized in that, The needle valve gap limiting structure also includes an electromagnet (10), which is disposed on the valve body (1) and sleeved on the iron core (3). When the electromagnet (10) is energized, the electromagnet (10) and the iron core (3) are magnetically attracted, and the needle valve (2) moves toward the return spring (9) so that the needle valve (2) opens the oil outlet of the valve body (1).

9. The needle valve gap limiting structure according to claim 8, characterized in that, Along the circumferential direction of the iron core (3), the outer peripheral wall of the limiting boss (4) is spaced apart from the inner side wall of the electromagnet (10).

10. A fuel injector, characterized in that, The invention includes the needle valve gap limiting structure according to any one of claims 1-9, wherein the needle valve gap limiting structure is used to limit the needle valve gap offset of the injector.

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