Assembling tool and assembling method for gap filter and oil inlet connector

Abstract

The invention provides an assembling tool and method for a gap filter and an oil inlet connector, the gap filter comprises an interference section, a gap section and a stamping section, the interference section is of a conical structure with the diameter gradually reduced, the minimum diameter of the interference section is located at the connecting position of the interference section and the gap section, and the stamping section is located at the connecting position of the gap section. The diameter of the gap section and the diameter of the stamping section are evenly arranged, and a stamping taper hole is formed in the end of the stamping section. The assembling tool is composed of a base, a pressing head, a pre-tightening spring, a pressure limiting piece and a pressure gauge, the pre-tightening spring is arranged in the base, one end of the pre-tightening spring is connected with the pressing head, the pressure limiting piece is arranged on the base, one end of the pressure limiting piece extends into the pre-tightening spring, the pressure gauge is arranged at the other end of the pressure limiting piece, and a gap is reserved between the pressure limiting piece and the pressing head. The assembling depth and the pre-tightening force of the gap filter can be effectively controlled, and the assembling standard and efficiency of the gap filter are improved.

Description

Technical Field

[0001] This application belongs to the technical field of diesel engine fuel injectors, and particularly relates to an assembly tool and an assembly method for a slit filter and an oil inlet joint. Background Art

[0002] In the engine fuel system, the fuel injector is the final component that realizes fuel injection into the cylinder. During the process of fuel entering the cylinder from the fuel tank, it will undergo filtration and pressurization. Especially in the high-pressure common rail system, the fuel is increased to over 100 MPa by the high-pressure pump. After that, it enters the common rail pipe and the common rail fuel injector and then is injected into the cylinder. However, the pressure-bearing capacity of general fuel filters is much lower than 100 MPa. This requires that the high-pressure fuel discharged from the high-pressure pump must be clean. At the same time, higher requirements are put forward for the cleanliness, reliability of the high-pressure oil circuit between the high-pressure pump and the common rail fuel injector, and the replacement of components. Therefore, to prevent foreign objects from entering the interior of the fuel injector and causing abnormal fuel injection such as increased fuel injection volume and continuous injection, a slit filter structure is generally installed in the oil inlet joint of the fuel injector or the oil outlet joint of the common rail pipe.

[0003] The clearance size between the clearance section of the slit filter and the oil inlet joint determines the filtering effect on foreign objects in the fuel and protects the normal fuel injection of the fuel injector. However, if the clearance is too small, although the filtering effect is enhanced, it will have a strong throttling effect on the fuel, resulting in a pressure difference before and after the slit filter. During fuel injection, the internal pressure of the fuel injector drops rapidly. At this time, the pressure at the upper end of the slit filter is higher than the pressure at the lower end of the slit filter, resulting in a hydraulic pressure that pushes the slit filter into the interior of the oil inlet joint. When this hydraulic pressure reaches the interference force of the slit filter, it will cause the slit filter to sink. At the end of fuel injection, the internal pressure of the fuel injector rises rapidly under the action of "water hammer". At this time, the pressure at the upper end of the slit filter is lower than the pressure at the lower end of the slit filter, resulting in a hydraulic pressure that pushes the slit filter out of the oil inlet joint. When this hydraulic pressure reaches the interference force of the slit filter, it will cause the slit filter to move upward. Due to the continuous occurrence of the fuel injection process, the slit filter is continuously subjected to alternating hydraulic forces, which will reduce the working reliability of the slit filter.

[0004] With the increase in engine power, the required engine fuel injection volume increases, and the contradiction between the throttling and filtering effects of the slit filter becomes increasingly prominent. For this reason, increasing the number of the filtering oil channels of the slit filter from two to three, or increasing the length of the filtering section, can increase the filtering area of the slit filter and reduce the flow rate effect, but both methods will be limited by the structural dimensions of the inlet joint. Designing both ends of the slit filter into interference sections or increasing the length of the interference section can increase the pre-tightening force of the slit filter, but it will increase the length of the slit filter itself or reduce the length of the clearance section, resulting in a reduction in the filtering area and an increase in the throttling effect. In addition, during the installation process of the slit filter, only the installation force or installation depth is generally considered. Affected by the oil channel size of the inlet joint and the interference size error of the slit filter, differences in the installation depth and pre-tightening force of the slit filter will occur. Through visual inspection, the difference in the installation depth of the slit filter can be detected, while the difference in the pre-tightening force still needs to be detected by an instrument, which instead reduces the installation efficiency of the slit filter. Summary of the Invention

[0005] In view of this, the present application aims to propose an assembly tool and an assembly method for a slit filter and an inlet joint. By adjusting the interference section structure of the slit filter, the pre-tightening force of the slit filter increases more uniformly with the increase in the insertion depth compared to the uniform diameter, and at the same time, adjusting the installation control parameters of the slit filter and increasing the inspection of the slit filter can achieve the purpose of improving the pre-tightening force of the slit filter while increasing the installation standard and efficiency of the slit filter.

[0006] To achieve the above object, the technical solution of the present application is realized as follows: In a first aspect, the present application provides an assembly tool for a slit filter and an inlet joint, which is used to fixedly assemble the slit filter and the inlet joint. Among them, the slit filter includes an interference section, a clearance section, and a stamping section. The interference section adopts a tapered structure with a gradually decreasing diameter. The minimum diameter of the interference section is located at the connection with the clearance section. The diameters of the clearance section and the stamping section are uniformly set, and a stamping taper hole is provided at the end of the stamping section. The assembly tool is composed of a base, a pressing head, a pre-tightening spring, a pressure limiting member, and a pressure gauge. The pre-tightening spring is installed in the base, and one end is connected to the pressing head. The pressure limiting member is installed on the base, and one end extends into the pre-tightening spring. The pressure gauge is arranged at the other end of the pressure limiting member, and a gap is reserved between the pressure limiting member and the pressing head.

[0007] Further, the minimum diameter of the interference section > the oil channel diameter of the inlet joint > the diameter of the stamping section ≥ the diameter of the clearance section.

[0008] Further, the pressing force of the slit filter is equal to the sum of the spring force of the pre-tightening spring and the pressing force of the pressure limiting member.

[0009] Further, a safety range, an over-standard range, and an insufficient range are provided on the pressure gauge to characterize the interference force index of the slit filter.

[0010] Further, the base is a two-stage stepped structure, and an inner hole for installing the pre-tightening spring and the pressure limiting member is provided therein.

[0011] In a second aspect, based on the same inventive concept, the present application further provides an assembly method for a slit filter and an oil inlet joint, including: According to the assembly tool for a slit filter and an oil inlet joint described in the first aspect, the stamping section of the slit filter is inserted into the oil inlet joint along the oil inlet end of the oil inlet joint, and then the slit filter is pressed in through the assembly tool. In response to the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint conforming to a preset value, and the pressure gauge index being within the safety range, it is determined that the first step of installing the slit filter is completed; Put a spacer block into the oil inlet end of the oil inlet joint and press against the slit filter, and punch the stamping section with a punch to form a punched tapered hole.

[0012] Further, in response to the pressure gauge index being within the over-standard range, and the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint being greater than the preset value, it is determined that the interference force of the slit filter is greater than the standard value, and then the slit filter is replaced; In response to the pressure gauge index being within the insufficient range, and the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint being equal to the preset value, it is determined that the interference force of the slit filter is less than the standard value, and then the slit filter is replaced; In response to the pressure gauge index being within the safety range, and the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint being equal to the set value, it is determined that the interference force of the slit filter conforms to the standard value, and then the first step of installing the slit filter is completed.

[0013] Compared with the prior art, the assembly tool and the assembly method for a slit filter and an oil inlet joint described in the present application have the following beneficial effects: (1) In the present application, by designing the interference section of the slit filter as a tapered structure, the interference force is increased. At the same time, a stamping structure is designed at the other end of the slit filter. After stamping, a tapered structure is also formed at the other end of the slit filter, further limiting the risk of the slit filter sinking or moving up.

[0014] (2) In the present application, by using the assembly tool, it can be judged whether the processing dimensions are appropriate during the first step of installing the slit filter, and the inspection of the slit filter is completed; at the same time, the assembly depth and the pre-tightening force of the slit filter can also be controlled, improving the assembly standard and efficiency of the slit filter. Description of the Drawings

[0015] The accompanying drawings, which form a part of this application, are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation of this application. In the drawings: Figure 1 It is a schematic structural diagram of a slit filter, an oil inlet joint, and an assembly tool according to an embodiment of this application; Figure 2 It is a schematic structural diagram of a punch according to an embodiment of this application; Figure 3 It is a schematic structural diagram of a spacer according to an embodiment of this application; Figure 4 It is a schematic diagram of the index range of the pressure gauge dial according to an embodiment of this application; Figure 5 It is a schematic diagram of an assembly method of a slit filter and an oil inlet joint according to an embodiment of this application.

[0016] Explanation of reference numerals: 1 - Slit filter; 2 - Interference section; 3 - Clearance section; 4 - Stamping section; 5 - Oil inlet joint; 6 - Oil outlet end; 7 - Oil inlet end; 8 - Compression head; 9 - Preloading spring; 10 - Base; 11 - Pressure limiting member; 12 - Pressure gauge; 13 - Punch; 14 - Spacer. Detailed implementation manners

[0017] To make the objectives, technical solutions, and advantages of this application clearer and more understandable, the following further elaborates on this application in detail with reference to specific embodiments and the accompanying drawings.

[0018] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of this application should have the ordinary meanings understood by those of ordinary skill in the field to which this application belongs. The "first", "second", and similar terms used in the embodiments of this application do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0019] Embodiment 1 Please refer to Figure 1As shown in the figure, the present application provides an assembly tool for a slit filter 1 and an oil inlet joint 5, which is used to fixedly assemble the slit filter 1 and the oil inlet joint 5. Among them, the slit filter 1 includes an interference section 2, a clearance section 3 and a stamping section 4. The interference section 2 adopts a tapered structure with a gradually decreasing diameter. The minimum diameter of the interference section 2 is located at the connection with the clearance section 3. The diameters of the clearance section 3 and the stamping section 4 are uniformly set. The minimum diameter of the interference section 2 > the oil passage diameter of the oil inlet joint 5 > the diameter of the stamping section 4 ≥ the diameter of the clearance section 3. A stamping taper hole is provided at the end of the stamping section 4; The assembly tool is composed of a base 10, a pressing head 8, a preloading spring 9, a pressure limiting member 11 and a pressure gauge 12. The preloading spring 9 is installed in the base 10 and one end is connected to the pressing head 8. The pressure limiting member 11 is installed on the base 10 and one end extends into the preloading spring 9. The pressure gauge 12 is arranged at the other end of the pressure limiting member 11. A gap is reserved between the pressure limiting member 11 and the pressing head 8; The base 10 is a two-stage stepped structure, and an inner hole for installing the preloading spring 9 and the pressure limiting member 11 is opened therein, as Figure 4 shown, the pressure gauge 12 is provided with a safety range, an over-standard range and an insufficient range to characterize the interference force index of the slit filter 1.

[0020] Specifically, in this embodiment, the present application designs the interference section 2 of the slit filter 1 as a tapered structure, so that the interference force increases. At the same time, a stamping structure is designed at the other end of the slit filter 1. After stamping, a tapered structure is also formed at the other end of the slit filter 1, further limiting the risk of the slit filter 1 sinking or moving up.

[0021] As the insertion depth of the slit filter 1 increases, the assembly interference force of the slit filter 1 increases. The increase in the interference force is composed of the acting length of the interference section 2 and the continuously increasing interference size.

[0022] The pressing head 8 does not contact the pressure limiting member 11 initially. The distance D2 (the distance between the second-stage stepped end face of the base 10 and the upper end face of the slit filter 1) extending out of the base 10 is smaller than the distance D3 (the distance between the first-stage stepped end face of the base 10 and the upper end face of the oil inlet joint 5). As the pressure increases, the distance D2 decreases. When the distance D2 decreases to the distance D1 (the distance D1 is the final insertion depth of the slit filter 1 into the oil inlet joint 5), the pressing head 8 contacts the pressure limiting member 11.

[0023] The pressure gauge 12 rotates clockwise, and the initial value is 0. The larger the rotation angle of the pointer, the greater the pressure. The pressing force of the slit filter 1 is equal to the sum of the spring force of the preloading spring 9 and the pressing force of the pressure limiting member 11.

[0024] This application uses the interference end with taper of the slit filter 1 to provide the oil inlet resistance during oil injection, preventing the slit filter 1 from sinking. At the same time, the stamping end is used to provide the oil return resistance generated by water hammer during oil cut-off, preventing the slit filter 1 from moving up, improving the installation reliability of the slit filter 1, and avoiding the problem that the slit filter 1 moves up and down in the oil inlet joint 5 due to insufficient installation resistance, and in severe cases, debris generated by abnormal displacement enters the injector, causing abnormal operation of the injector. This application uses this assembly tool to judge whether the processing size is appropriate during the first-step installation of the slit filter 1, complete the inspection of the slit filter 1, and at the same time control the assembly depth and pre-tightening force of the slit filter 1, improving the assembly standard and efficiency of the slit filter 1.

[0025] Embodiment 2 An assembly method for the slit filter 1 and the oil inlet joint 5, according to the assembly tool for the slit filter 1 and the oil inlet joint 5 described in Embodiment 1, includes: Insert the stamping section 4 of the slit filter 1 into the oil inlet joint 5 along the oil inlet end 7 of the oil inlet joint 5, and then press the slit filter 1 through the assembly tool. In response to the distance between the first-step stepped end face of the base 10 and the upper end face of the oil inlet joint 5 meeting the preset value and the index of the pressure gauge 12 being within the safe range, it is determined that the first step of installing the slit filter 1 is completed. Place the spacer 14 (the structure of the spacer 14 is as shown in 3) into the oil inlet end 7 of the oil inlet joint 5 and hold the slit filter 1, and punch the stamping section 4 through the punch 13 (the structure of the punch 13 is as shown in 4) to form a stamping tapered hole.

[0026] Specifically, in this embodiment, as Figure 5 shown in ①, after the slit filter 1 is placed into the oil inlet end 7 of the oil inlet joint 5, since the diameters of the clearance section 3 and the stamping section 4 are smaller than the oil passage diameter of the oil inlet joint 5, the slit filter 1 will automatically sink until the interference section 2 is stuck on the oil inlet passage of the oil inlet joint 5 after being placed. Then, the pressing head 8 of the assembly tool with limit and pressure display is naturally attached to the upper top surface of the slit filter 1. At this time, the pre-tightening spring 9 is not deformed, the pressing head 8 and the pressure limiting member 11 are not attached, and the display value of the pressure gauge 12 is 0.

[0027] As Figure 5 shown in ②, apply a downward pressure to the assembly tool with limit and pressure display. At this time, the pressing head 8 pushes the slit filter 1 to sink, and the distance D2 between the pressing head 8 and the assembly tool with limit and pressure display is reduced. The reduced part pushes the pre-tightening spring 9 to deform. The deformation of the pre-tightening spring 9 increases, the spring force increases, and the slit filter 1 is pushed to sink further. At this time, the pressing force of the slit filter 1 is equal to the elastic force of the pre-tightening spring 9 and the downward pressure applied to the assembly tool with limit and pressure display.

[0028] As Figure 5As shown in ③, as the downward pressure applied to the assembly tool with a limit and pressure display increases, the distance D2 continues to decrease, the early warning spring force increases, pushing the gap filter 1 to sink, and the interference force of the interference section 2 increases. When the rate of increase of the interference force is greater than the rate of increase of the early warning spring force, the downward pressure applied to the assembly tool with a limit and pressure display no longer prevents the gap filter 1 from sinking, but only reduces the distance D2. When the distance D2 is reduced to the point where the clamping head 8 contacts the pressure limiting part 11, the early warning spring force reaches its maximum. At this time, the gap filter 1 still no longer sinks, and the downward pressure applied to the assembly tool with a limit and pressure display begins to act on the clamping head 8. The clamping head 8 and the early warning spring act together on the gap filter 1. The force of the clamping head 8 is displayed by the pressure gauge 12. The downward pressure applied to the assembly tool with a limit and pressure display continues to increase, and the value displayed on the pressure gauge 12 increases. At this time, there are three situations: 1. The gap filter 1 slowly sinks or still does not sink. When the distance D3 is greater than the preset value d (the preset value can be flexibly set according to the actual situation, and the specific preset value is not limited), the pointer of the pressure gauge 12 reaches the over-standard range, indicating that the interference size of the gap filter 1 is too large or the oil channel size of the oil inlet joint 5 is too small, and one of them needs to be replaced. Since the cost of the gap filter 1 is lower than that of the oil inlet joint 5, the solution of replacing the gap filter 1 is adopted; 2. The gap filter 1 continues to sink. When the distance D3 is equal to the preset value d, the pointer of the pressure gauge 12 reaches the insufficient range, indicating that the interference size of the gap filter 1 is too small or the size of the oil channel of the oil inlet joint 5 is too large, and the gap filter 1 also needs to be replaced; 3. The gap filter 1 continues to sink. When the distance D3 is equal to the preset value and the pointer of the pressure gauge 12 reaches the safe range, it indicates that the size of the gap filter 1 and the oil inlet joint 5 are well matched. At this time, the installation position and preload force of the gap filter 1 have reached the preset value. You can continue with the subsequent installation.

[0029] like Figure 5 As shown in ④, the installation of the interference section 2 of the gap filter 11 is completed.

[0030] like Figure 5 As shown in ⑤, after the installation of the interference section 2 of the gap filter 1 is completed, the gasket 14 is placed in the oil inlet end 7 of the oil inlet joint 5 to support the gap filter 1, and then the stamping section 4 is punched with a special punch 13 to complete the second step of the installation of the gap filter 1. Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it; although the present invention is described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to replace part or all of the technical features therein by equivalent; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specifications of the present invention.

[0031] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A gap filter and oil inlet joint assembly tool, used for fixing and assembling the gap filter and the oil inlet joint, wherein: The gap filter comprises an interference section, a gap section and a stamping section, and is characterized in that: The interference section adopts a tapered structure with a gradually decreasing diameter, the minimum diameter of the interference section is located at the connection with the gap section, the diameters of the gap section and the punching section are evenly set, and the end of the punching section is provided with a punching cone hole; The assembly tool consists of a base, a clamping head, a preload spring, a pressure limiting part and a pressure gauge. The preload spring is installed in the base, and one end is connected to the clamping head. The pressure limiting part is installed on the base, and one end extends into the preload spring. The pressure gauge is arranged at the other end of the pressure limiting part, and a gap is reserved between the pressure limiting part and the clamping head.

2. The tool according to claim 1, characterized in that: The minimum diameter of the interference section>the oil channel diameter of the oil inlet joint>the stamping section diameter≥the gap section diameter.

3. The tool according to claim 1, characterized in that: The pressing force of the gap filter is equal to the sum of the spring force of the preload spring and the pressing force of the pressure limiting member.

4. The tool according to claim 1, characterized in that: The pressure gauge is provided with a safety interval, an over-standard interval and an under-standard interval to characterize the interference force index of the slot filter.

5. The tool according to claim 1, characterized in that: The base is a two-stage stepped structure, and is provided with an inner hole for installing the preload spring and the pressure limiting member.

6. A method for assembling a gap filter and an oil inlet joint, according to the assembly tool for a gap filter and an oil inlet joint according to any one of claims 1 to 5, characterized in that: include: Install the punched section of the gap filter into the oil inlet joint along the oil inlet end of the oil inlet joint, and then press the gap filter in with an assembly tool. If the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint meets the preset value, and the pressure gauge index is within the safe range, it is determined that the first step of the gap filter installation is completed; The gasket is placed into the oil inlet end of the oil inlet joint and against the gap filter, and the punching section is punched by a punch to form a punched cone hole.

7. The method according to claim 1, characterized in that: In response to the pressure gauge index being within the over-standard range, and the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint being greater than a preset value, it is determined that the gap filter interference force is greater than the standard value, and the gap filter is replaced; In response to the pressure gauge index being in the insufficient range and the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint being equal to the preset value, it is determined that the gap filter surplus force is less than the standard value, and the gap filter is replaced; In response to the pressure gauge index being within the safety range and the distance between the first-stage stepped end face of the base and the upper end face of the oil inlet joint being equal to the set value, it is determined that the gap filter interference force meets the standard value, and the first step of the gap filter installation is completed.

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