Anti-deflection guide piston assembly

Abstract

The utility model relates to an anti-skew guide piston assembly which is applied to a fuel injection pump and comprises a plunger, a guide piston and a limiting pin, an end is arranged at the lower end of the plunger, a bayonet is arranged on the guide piston, the central axis of the bayonet is collinear with the central axis of the guide piston, a loading opening is formed in the peripheral side of the bayonet, and the end is clamped into the bayonet through the loading opening. The plunger and the guide piston are axially connected together; the limiting pin is detachably connected to the guide piston, and a blocking part which is blocked at the loading opening to prevent the end in the bayonet from moving towards the loading opening is arranged on the limiting pin. The guide piston can be better prevented from being laterally deviated, and the assembly difficulty of the fuel injection pump can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of diesel engine electronic fuel injection systems, and particularly relates to an anti-tilting guide piston assembly. Background Art

[0002] As Figure 2 shown, the guide piston assemblies of some fuel injection pumps are connected by a clamping structure. A connecting portion 400 is provided on the guide piston 300, a bayonet 500 with a side opening is provided in the connecting portion 400, and a head 200 is provided at the lower end of the plunger 100. During assembly, the head 200 is snapped into the bayonet 500 through the side opening of the bayonet 500, and then a retaining ring 600 installed around the connecting portion 400 is used to prevent the head 200 from disengaging from the bayonet 500. Although the above-mentioned guide piston assembly realizes the anti-disengagement between the plunger and the guide piston, the following technical problems exist: the gap between the retaining ring and the plunger is large, and during the assembly and transportation of the fuel injection pump, the guide piston is prone to side deviation, resulting in the non-alignment of the guide piston and the plunger, and the overall skewing of the fuel injection pump, thereby making the assembly of the fuel injection pump difficult. Summary of the Utility Model

[0003] The purpose of the utility model is to propose an anti-tilting guide piston assembly to alleviate or eliminate at least one of the above technical problems.

[0004] An anti-tilting guide piston assembly described in the utility model is applied to a fuel injection pump and includes a plunger, a guide piston and a limit pin. A head is provided at the lower end of the plunger. A bayonet is provided on the guide piston. The central axis of the bayonet is collinear with the central axis of the guide piston. An insertion opening is provided on the periphery of the bayonet. The head is snapped into the bayonet through the insertion opening to axially connect the plunger and the guide piston together. The limit pin is detachably connected to the guide piston, and a blocking portion is provided on the limit pin to block the insertion opening to prevent the head in the bayonet from moving towards the insertion opening.

[0005] Optionally, the bayonet includes a large-diameter section and a small-diameter section located above the large-diameter section, and the outer diameter of the head is greater than the aperture of the small-diameter section.

[0006] Optionally, a pin hole with a central axis parallel to the central axis of the guide piston is provided on the guide piston, and the limit pin is installed in the pin hole.

[0007] Optionally, the pin hole is a stepped through hole, the stepped through hole includes a small hole section, a stepped surface and a large hole section arranged in sequence from top to bottom, the limit pin includes a pin body matched with the small hole section and a pin head matched with the large hole section, and the outer diameter of the pin head is greater than the inner diameter of the small hole section.

[0008] Optionally, a retaining ring installation groove is provided in the macroporous section, and a retaining ring for blocking the limit pin is installed in the retaining ring installation groove. The retaining ring is located below the limit pin, and the upper end of the pin body extends upward out of the pin hole to form the blocking portion.

[0009] Optionally, a roller installation cavity is provided in the lower part of the guiding piston, and the port at the lower end of the pin hole is arranged on the inner side surface of the roller installation cavity.

[0010] Optionally, an avoidance hole for the roller to pass through is provided below the roller installation cavity, and the port at the lower end of the pin hole is located above the avoidance hole.

[0011] The utility model can better prevent the guiding piston from being laterally deflected, which helps to reduce the assembly difficulty of the fuel injection pump. Description of the Drawings

[0012] Figure 1 It is a schematic structural diagram of the anti-skew guiding piston assembly described in the specific implementation manner;

[0013] Figure 2 It is a schematic structural diagram of the guiding piston assembly described in the background art.

[0014] Wherein, 1 - plunger; 2 - end head; 3 - guiding piston; 4 - connecting portion; 5 - bayonet; 6 - pin hole; 7 - retaining ring; 8 - limit pin; 9 - roller installation cavity; 10 - roller pin; 11 - roller; 12 - stop pin. Specific Embodiments

[0015] The following will describe the embodiments of the present utility model with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model. It should be understood that the preferred embodiments are only for explaining the present utility model, rather than for limiting the protection scope of the present utility model.

[0016] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present utility model in a schematic manner. Therefore, only the components related to the present utility model are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0017] As Figure 1An anti-skew guiding piston assembly shown is applied to a fuel injection pump and includes a plunger 1, a guiding piston 3 and a limit pin 8. A head 2 is provided at the lower end of the plunger 1. A connecting portion 4 is provided on the guiding piston 3, and a bayonet 5 is provided at the connecting portion 4. The central axis of the bayonet 5 is collinear with the central axis of the guiding piston 3. An insertion opening is provided on the circumferential side of the bayonet 5. The head 2 is snapped into the bayonet 5 through the insertion opening to axially connect the plunger 1 and the guiding piston 3 together. The limit pin 8 is detachably connected to the guiding piston 3, and a blocking portion is provided on the limit pin 8 to block the insertion opening to prevent the head 2 installed in the bayonet 5 from moving towards the insertion opening. With the above technical solution, by providing the limit pin 8 at the insertion opening, the gap between the limit pin 8 and the head 2 can be made smaller, which can better ensure the coaxiality between the plunger 1 and the guiding piston 3, and can reduce the possibility of the guiding piston 3 being laterally deflected, that is, it can better prevent the guiding piston 3 from being laterally deflected, which helps to reduce the assembly difficulty of the fuel injection pump.

[0018] In some embodiments, the bayonet 5 is a blind hole-like structure with openings at the upper end and the side. The bayonet 5 includes a large-diameter section and a small-diameter section located above the large-diameter section. The diameter of the large-diameter section is larger than that of the small-diameter section, and the outer diameter of the head 2 is larger than the diameter of the small-diameter section. With the above technical solution, the edge of the small-diameter section can axially limit the head 2 in the large-diameter section, thereby axially connecting the plunger 1 and the guiding piston 3 together. In specific implementation, a neck that cooperates with the small-diameter section is provided at the lower part of the plunger 1, and the outer diameter of the neck is smaller than the outer diameter of the head 2. When the head 2 is snapped into the large-diameter section through the insertion opening, the neck is snapped into the small-diameter section through the insertion opening.

[0019] In some embodiments, a pin hole 6 with a central axis parallel to the central axis of the guiding piston 3 is provided on the guiding piston 3, and the limit pin 8 is installed in the pin hole 6. With the above technical solution, providing the pin hole 6 facilitates the installation of the limit pin 8.

[0020] In some embodiments, the pin hole 6 is a stepped through-hole. The stepped through-hole includes a small-hole section, a stepped surface and a large-hole section with a diameter larger than that of the small-hole section arranged in sequence from top to bottom. The limit pin 8 includes a pin body that cooperates with the small-hole section and a pin head that cooperates with the large-hole section. The outer diameter of the pin head is larger than the inner diameter of the small-hole section. With the above technical solution, the stepped surface can block the pin head of the limit pin 8 to limit the axial position of the limit pin 8. In specific implementation, the pin body and the small-hole section can be fixedly connected by means of a threaded fit.

[0021] In some embodiments, a retaining ring 7 mounting groove is provided in the macroporous section. A retaining ring 7 that blocks and limits the position of the pin 8 is mounted in the retaining ring 7 mounting groove. The retaining ring 7 is located below the limit pin 8, and the upper end of the pin body extends upward out of the pin hole 6 to form a blocking portion. With the above technical solution, the retaining ring 7 is used to support the limit pin 8, which can prevent the limit pin 8 from detaching from the pin hole 6. In specific implementation, the retaining ring 7 can be a C-shaped snap ring, and the pin head of the limit pin 8 is limited between the retaining ring 7 and the step surface.

[0022] In some embodiments, a roller mounting cavity 9 is provided in the lower part of the guide piston 3, and the lower end port of the pin hole 6 is arranged on the inner side surface of the roller mounting cavity 9. With the above technical solution, the roller mounting cavity 9 can be used as the installation channel for the limit pin 8 and the retaining ring 7, which helps to reduce the difficulty of disassembling and assembling the limit pin 8 and the retaining ring 7.

[0023] In some embodiments, an avoidance hole for the roller 11 to pass through is provided below the roller mounting cavity 9, and the lower end port of the pin hole 6 is located above the avoidance hole. With the above technical solution, the avoidance hole and the roller mounting cavity 9 can be used as the installation channel for the limit pin 8 and the retaining ring 7, which helps to reduce the difficulty of disassembling and assembling the limit pin 8 and the retaining ring 7.

[0024] In some embodiments, when the plunger 1 and the guide piston 3 are coaxial, there is a small gap between the blocking portion and the end 2. With the above technical solution, the radial movement of the plunger 1 can be better reduced during transportation and assembly, the possibility of the guide piston 3 being laterally deflected can be reduced, that is, the situation of the guide piston 3 being laterally deflected can be better prevented, which helps to reduce the assembly difficulty of the fuel injection pump.

[0025] In specific implementation, the roller 11 can be mounted in the roller mounting cavity 9 through a roller pin 10. A stop pin 12 that presses against the roller pin 10 is mounted in the guide piston 3. The stop pin 12 can fix the roller pin 10 in the guide piston 3. The roller 11 extends out of the guide piston 3 through the avoidance hole, so that the roller 11 can contact the camshaft of the fuel injection pump.

[0026] The above embodiments are only preferred embodiments given to fully illustrate the present utility model, and the protection scope of the present utility model is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present utility model are all within the protection scope of the present utility model. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics of the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0027] In the description of the present utility model, it should be understood that the orientations indicated by terms such as "upper" and "lower" are based on the Figure 1 coordinate system shown in the appendix, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present utility model.

Claims

1. An anti-skew guide piston assembly, applied to a fuel injection pump, characterized in that: It includes a plunger, a guide piston and a limit pin, the lower end of the plunger is provided with an end head, the guide piston is provided with a bayonet, the central axis of the bayonet is colinear with the central axis of the guide piston, the peripheral side of the bayonet is provided with an insertion opening, the end head is inserted into the bayonet through the insertion opening to axially connect the plunger and the guide piston together; the limit pin is detachably connected to the guide piston, and the limit pin is provided with a blocking part that blocks the insertion opening to prevent the end head in the bayonet from moving toward the insertion opening.

2. The anti-skew guide piston assembly according to claim 1, characterized in that: The bayonet comprises a large-aperture section and a small-aperture section located on the upper side of the large-aperture section, and the outer diameter of the end head is larger than the aperture of the small-aperture section.

3. The anti-skew guide piston assembly according to claim 1, characterized in that: The guide piston is provided with a pin hole whose central axis is parallel to the central axis of the guide piston, and the limit pin is installed in the pin hole.

4. The anti-skew guide piston assembly according to claim 3, characterized in that: The pin hole is a stepped through hole, which includes a small hole section, a stepped surface and a large hole section arranged in sequence from top to bottom. The limit pin includes a pin body that cooperates with the small hole section and a pin head that cooperates with the large hole section. The outer diameter of the pin head is larger than the inner diameter of the small hole section.

5. The anti-skew guide piston assembly according to claim 4, characterized in that: The large hole section is provided with a retaining ring installation groove, in which a retaining ring for blocking the limit pin is installed. The retaining ring is located at the lower side of the limit pin, and the upper end of the pin body extends upward from the pin hole to form the blocking portion.

6. The anti-skew guide piston assembly according to claim 3, characterized in that: A roller installation cavity is arranged at the lower part of the guide piston, and a port at the lower end of the pin hole is arranged on the inner side surface of the roller installation cavity.

7. The anti-skew guide piston assembly according to claim 6, characterized in that: A avoidance hole for the roller to pass through is arranged on the lower side of the roller installation cavity, and the port at the lower end of the pin hole is located above the avoidance hole.

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