A press fitting device and press fitting method for a fuel pump plunger and an armature

Abstract

This invention discloses a pressing device and method for pressing a fuel pump plunger and an armature. The pressing device includes a worktable fixedly connected to a fuel suction and discharge valve; a screw lifting mechanism located below the worktable for driving the lifting platform to rise and fall; a lifting platform located between the screw lifting mechanism and the lower side of the worktable, including a base, a lifting cylinder, and a lifting plate, the movement of which is controlled by the piston rod movement controlled by the lifting cylinder; and a locking mechanism arranged between the base and the upper end of a servo motor to prevent the screw lifting mechanism from descending under pressure. This method is simple to operate, accurately controls the pressing gap between the fuel pump and the armature, and has high control precision.

Description

Technical Field

[0001] This invention relates to the field of press-fitting technology, and more specifically, to a press-fitting apparatus and method for a fuel pump plunger and armature. Background Technology

[0002] like Figure 4 As the core component of the automotive fuel supply system, the fuel pump shown has a suction and discharge valve 7 mounted on it. The suction and discharge valve 7 has a connected pressurization chamber 9 and a plunger hole, and extends from bottom to top through the suction and discharge valve 7. The plunger 2 is installed in the plunger hole, and the armature 8 is installed on the upper end of the plunger 2. During operation, the armature 8 drives the lower cone of the plunger 2 to close the pressurization chamber 9. During other operations, the lower cone of the plunger forms a small gap with the pressurization chamber 9. The size of the gap directly affects the engine's starting, running stability, and fuel economy. The solenoid valve controls the inlet and return oil passages of the plunger pump. When the armature 8 of the solenoid valve closes the pressurization chamber 9 of the suction and discharge valve 7 at the lower end of the plunger 2, it needs to maintain an allowable gap Y with the sealing ring 10 at the upper end of the plunger hole. The allowable gap Y is 0.75±0.05mm, so as to realize the intake and pressurized delivery of fuel. The press-fit structure between the two affects the response time and high-pressure sealing of the solenoid valve, which in turn affects the working performance and service life of the fuel pump. In the actual manufacturing process, the control of the assembly gap between the armature and the pump body has always been one of the key factors affecting the consistency and reliability of fuel pump performance. In the existing technology, since the oil suction and discharge valve 7 is a casting, the manufacturing tolerance of the pressure chamber 9 is relatively large. The plunger 2 is a machined part with precise and controllable tolerance. When the manufacturing tolerance and assembly error of the armature 8 and the plunger 2 are pressed onto the plunger 2, the pressure chamber 9 tolerance may cause the press-fit gap to fail to meet the requirements. Once the traditional press-fit structure is assembled, the gap cannot be finely adjusted or compensated. Therefore, there is an urgent need for a press-fit method with a reasonable structure and controllable gap, which can meet the gap requirements of the sealing ring 10 at the upper end of the armature and the plunger hole after the armature and the plunger are pressed together. Summary of the Invention

[0003] This invention provides a method for press-fitting a fuel pump plunger and armature. By controlling the plunger's rise and fall and combining sensor output data, the press-fitting gap can be strictly controlled, and the operation is simple.

[0004] To achieve the above objectives, the technical solution of the present invention is: a press-fitting device for a fuel pump plunger and an armature, comprising... The workbench is set up and kept horizontal. A through hole is provided in the center of the workbench, penetrating the upper and lower surfaces. The oil suction and discharge valve is configured to keep the pressure chamber facing downward and aligned with the workpiece table through the through hole and fixed on the workbench. A lead screw lifting mechanism, located below the worktable, is used to drive the lifting platform to rise and fall, and includes a lead screw; The lifting platform is located between the lead screw lifting mechanism and the lower side of the worktable. It includes a base, a lifting cylinder and a lifting plate. The base is fixed to the upper end of the lead screw. The lifting cylinder is located in the center of the lower side of the base. The upper end of the piston rod of the lifting cylinder is connected to the bottom surface of the lifting plate. When the piston rod retracts, the bottom surface of the lifting plate contacts the upper side of the base. A push rod is arranged in the center of the upper side of the lifting plate. A spring is located between the lifting plate and the worktable and is used to push the lifting plate (16) back to contact the upper side of the base. A displacement sensor is also installed on the upper side of the lifting plate to detect the distance between the lifting plate and the bottom surface of the worktable.

[0005] The locking mechanism is located between the base and the upper end of the servo motor of the lead screw lifting mechanism to prevent the lead screw lifting mechanism from descending under pressure.

[0006] The lower end of the lead screw is pivotally connected to the output shaft of the servo motor. The lead screw assembly is fitted around the outer circumference of the lead screw, and a lifting platform is installed at the upper end of the lead screw assembly. The lead screw is used to drive the lead screw assembly to lift and lower precisely.

[0007] A recessed cavity facing the through hole is centrally located on the upper side of the base, and the lifting cylinder is centrally located in the recessed cavity.

[0008] Guide rods are evenly arranged around the push rod, and guide holes facing the lifting plate are evenly arranged around the through hole of the workpiece table. The guide holes are aligned with the guide rods, and the push rods are aligned with the through holes. Springs are sleeved on the outer periphery of the guide holes.

[0009] The locking mechanism includes a base, optical shafts, and a brake. The base is fixedly connected to the servo motor. The optical shafts are fixed on the underside of the base and are evenly distributed around the lead screw. The lower end of the optical shaft passes through the base and is slidably connected to the base. Each optical shaft is fitted with a brake, which is fixedly connected to the base.

[0010] A method for press-fitting a fuel pump plunger and an armature, using the aforementioned press-fitting device for the fuel pump and armature, includes the following steps: S1. The oil suction and discharge valves are pressed onto the worktable by the pressing mechanism; S2. The piston rod of the lifting cylinder inside the lifting platform retracts into the cavity and is in the initial position. Record the distance H1 between the lifting plate on the displacement sensor and the lower surface of the workpiece table. S3. The lifting platform drives the lifting rod to rise until the piston in the oil suction and discharge valve supported by the lifting rod contacts the top of the pressurization chamber. Record the distance H2 between the lifting plate and the lower surface of the workpiece table on the displacement sensor. Retract the piston rod of the lifting cylinder until the lifting plate contacts the base. S4. The servo motor controls the lead screw to rotate, thereby causing the base to move upward. The upward movement of the base pushes the push rod and plunger to move upward. At the same time, the reading of the displacement sensor is read. When the reading is H1-H2-Y, the push rod reaches the preset position. S5. The press descends, pressing the armature onto the plunger. Under pressure, the armature also descends along the plunger to the sealing ring at the upper end of the armature hole in S4. At this point, the top of the sealing ring at the upper end of the armature hole is in contact with the armature, and the armature is fitted onto the plunger. This invention, by controlling the lifting and lowering of the plunger and combining sensor output data, satisfies the gap requirement of the sealing ring at the upper end of the armature and plunger hole after the armature and plunger are press-fitted. The method is simple to operate and has high control precision. Attached Figure Description

[0011] Figure 1 This is a connection diagram during the press-fitting process of the present invention; Figure 2 This is a cross-sectional view of the internal structure during the press-fitting process of the present invention; Figure 3 for Figure 2 A magnified view of a specific part of the image; Figure 4 This is a schematic diagram of the oil suction and discharge valve. Detailed Implementation

[0012] In order to better understand the technical content of the present invention, the following embodiments are provided in detail. The purpose of these embodiments is only to better understand the content of the present invention and not to limit the scope of protection of the present invention.

[0013] Example 1 A press-fitting device for a fuel pump plunger and armature includes a worktable 1, a lifting platform, a lead screw lifting mechanism, and a locking mechanism. The worktable 1 is erected and kept horizontal, and has a through hole 12 that passes through the upper and lower surfaces. The oil suction and discharge valve 7 is configured to keep the pressurization chamber 9 facing downward and aligned with the through hole 12 of the workpiece platform 1 and is fixed on the worktable 1.

[0014] The lead screw lifting mechanism is located below the worktable 1. The lead screw lifting mechanism includes a servo motor 6, a lead screw 13, and a lead screw pair 14. The lower end of the lead screw 13 is pivotally connected to the output shaft of the servo motor 6. The lead screw pair 14 is fitted around the outer periphery of the lead screw 13. A lifting platform is installed on the upper end of the lead screw pair 14. The lead screw 13 is used to drive the lead screw pair 14 to lift and lower precisely.

[0015] The lifting platform is positioned between the lead screw 13 and the lower side of the worktable 1, and includes a base 15, a lifting cylinder 4, a lifting plate 16, a push rod 3, a guide rod 19, and a spring 21. The base 15 is fixed to the upper end of the lead screw 13, and a recess 17 facing the through hole 12 is centrally located on the upper side of the base 15. The lifting cylinder 4 is centrally located in the recess 17, and the upper end of the piston rod 18 of the lifting cylinder 4 is connected to the bottom surface of the lifting plate 16. When the piston rod 18 retracts, the bottom surface of the lifting plate 16 contacts the piston rod 18. On the upper side of the base 15, a top rod 3 is centrally arranged on the upper side of the lifting plate 16. Guide rods 19 are evenly arranged around the top rod 3. Guide holes 20 facing the lifting plate 16 are evenly arranged around the through hole 12 of the workpiece table 1. The guide holes 20 are aligned with the guide rods 19, and the top rods 3 are aligned with the through hole 12. A spring 21 is sleeved on the outer periphery of the guide hole 20 and located between the lifting plate 16 and the guide hole 20. The spring 21 is used to push the lifting plate 16 back to the upper side of the base 15.

[0016] The locking mechanism is arranged between the base 15 and the upper end of the servo motor 6, including a base 22, an optical axis 23, and a brake 24. The base 22 has a central shaft hole 25, through which the lead screw 13 passes. The base 22 is fixedly connected to the servo motor 6. The optical axis 23 is fixed on the lower side of the base 15 and is evenly distributed around the shaft hole 25. The lower end of the optical axis 23 passes through the base 22 and is slidably connected to the base 22. Each optical axis 23 is fitted with a brake 24, which is fixedly connected to the base 22.

[0017] Preferably, a displacement sensor 26 is also installed on the upper side of the lifting plate 16 to detect the distance between the lifting plate 16 and the bottom surface of the workpiece table 1.

[0018] A method for press-fitting a fuel pump plunger and an armature includes the following steps: Step 1. Install the oil suction and discharge valve 7 horizontally on the workpiece table 1, so that the pressure chamber 9 of the oil suction and discharge valve 7 faces downward and is aligned with the through hole 12 of the workpiece table 1, so that the push rod 3 can support the plunger 2 inside the oil suction and discharge valve 7, and press the oil suction and discharge valve 7 onto the workpiece table 1 through the pressing mechanism 12. Step 2. At this time, the piston rod of the lifting cylinder 4 inside the lifting platform retracts into the cavity 17 and is in the initial position. Record the distance H1 between the lifting plate 16 on the displacement sensor 26 and the lower surface of the workpiece table 1. Step 3. The lifting platform drives the lifting rod 3 to rise until the piston 2 inside the oil suction and discharge valve 7 supported by the lifting rod 3 contacts the top of the pressurization chamber 9. Record the distance H2 between the lifting plate 16 and the lower surface of the workpiece table 1 on the displacement sensor 26. Retract the piston rod of the lifting cylinder 4 until the lifting plate 16 contacts the base 15. Step 4. Servo motor 6 controls lead screw 13 to rotate, thereby causing base 15 to move upward. The upward movement of base 15 pushes push rod 3 and plunger 2 to move upward. At the same time, the reading of displacement sensor 26 is read. When the reading is H1-H2-Y, push rod 3 reaches the preset position. Step 5. The press descends, pressing the armature onto the plunger 2. Under pressure, the armature will also descend along the plunger 2 to the sealing ring 10 at the upper end of the armature hole in S4. At this time, the armature is connected to the top of the sealing ring 10 at the upper end of the armature hole, and the armature is sleeved on the plunger 2.

[0019] When the plunger 2 moves upward to the top of the pressurized chamber 9, the gap between the lower side of the armature and the upper end of the sealing ring 10 of the armature hole is Y. In this embodiment, Y = 0.75 ± 0.05 mm.

[0020] In the existing technology for press-fitting the armature of the suction and discharge valve, assuming that the manufacturing tolerance of the suction and discharge valve is small, the distance L from the top of the pressure chamber 9 to the upper sealing ring 10 of the plunger hole is a known value, and the distance P from the lower cone of the plunger 2 to the upper end of the plunger 2 is a known value. The length of the upper end of the plunger 2 protruding from the upper sealing ring 10 of the plunger hole is adjusted to PLY. Then, a scale line is marked where the plunger 2 aligns with the upper sealing ring 10 of the plunger hole. The press descends, pressing the armature 8 onto the plunger 2 so that the lower end of the armature 8 aligns with the scale line on the plunger 2. In this operation, if the actual distance from the top of the pressure chamber 9 of the suction and discharge valve to the upper sealing ring 10 of the plunger hole is less than L, then when the lower cone of the plunger 2 closes the pressure chamber 9 of the suction and discharge valve 7, the gap between the armature 8 and the upper sealing ring 10 of the plunger hole is greater than the allowable gap Y. If the actual distance from the top of the pressure chamber 9 of the suction and discharge valve to the upper sealing ring 10 of the plunger hole is greater than L, then when the lower cone of the plunger 2 closes the pressure chamber 9 of the suction and discharge valve 7, the distance between the armature 8 and the upper sealing ring 10 of the plunger hole will be less than the allowable gap Y. Alternatively, the length of the upper end of the adjusting plunger 2 protruding from the upper sealing ring 10 of the plunger hole will be less than PLY. When the press descends and presses the armature 8 onto the plunger 2 so that the lower end of the armature 8 is aligned with the upper sealing ring 10 of the plunger hole, there will be no gap between the armature 8 and the upper sealing ring 10 of the plunger hole when the lower cone of the plunger 2 closes the pressure chamber 9 of the suction and discharge valve 7.

[0021] When pressing the armature using the above steps of this embodiment, regardless of whether the manufacturing tolerance of the oil suction and discharge valve is too large or too small, the armature 8 and the sealing ring 10 at the upper end of the plunger hole can maintain an allowable gap Y when the lower cone of the plunger 2 seals the pressurization chamber 9 of the oil suction and discharge valve 7.

[0022] The above description only illustrates the preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All modifications made within the scope of the independent claims of this invention are also within the scope of protection of this invention.

Claims

1. A press-fitting device for a fuel pump plunger and armature, characterized in that, include: The workbench (1) is erected and kept horizontal. The workbench (1) has a through hole (12) that runs through the top and bottom. The oil suction and discharge valve (7) is configured to keep the pressurization chamber (9) facing down and aligned with the through hole (12) of the workbench (1) and fixed on the workbench (1). A lead screw lifting mechanism is set below the worktable (1) and is used to drive the lifting platform to rise and fall, including a lead screw (13). The lifting platform is located between the screw lifting mechanism and the lower side of the worktable (1). It includes a base (15), a lifting cylinder (4), and a lifting plate (16). The base (15) is fixed to the upper end of the screw (13). The lifting cylinder (4) is located in the center of the lower side of the base (15). The upper end of the piston rod (18) of the lifting cylinder (4) is connected to the bottom surface of the lifting plate (16). When the piston rod (18) retracts, the bottom surface of the lifting plate (16) contacts the upper side of the base (15). A top rod (3) is arranged in the center of the upper side of the lifting plate (16). A spring (21) is located between the lifting plate (16) and the worktable (1) to push the lifting plate (16) back to contact the upper side of the base (15). A displacement sensor (26) is also installed on the upper side of the lifting plate (16) to detect the distance between the lifting plate (16) and the bottom surface of the worktable (1). The locking mechanism is located between the base (15) and the upper end of the servo motor (6) of the screw lifting mechanism to prevent the screw lifting mechanism from falling when it is under pressure.

2. The press-fitting device for a fuel pump plunger and armature according to claim 1, characterized in that, The lower end of the lead screw (13) is pivotally connected to the output shaft of the servo motor (6). The lead screw pair (14) is fitted around the outer periphery of the lead screw (13). A lifting platform is installed at the upper end of the lead screw pair (14). The lead screw (13) is used to drive the lead screw pair (14) to lift precisely.

3. The press-fitting device for a fuel pump plunger and armature according to claim 1, characterized in that, The base (15) has a recess (17) centered on the upper side facing the through hole (12), and the lifting cylinder (4) is centered in the recess (17).

4. The press-fitting device for a fuel pump plunger and armature according to claim 1, characterized in that, Guide rods (19) are evenly arranged around the top rod (3), and guide holes (20) facing the lifting plate (16) are evenly arranged around the through hole (12) of the worktable (1). The guide holes (20) are aligned with the guide rods (19), and the top rod (3) is aligned with the through hole (12). The spring (21) is sleeved on the outer periphery of the guide hole (20).

5. The press-fitting device for a fuel pump plunger and armature according to claim 1, characterized in that, The locking mechanism includes a base (22), an optical axis (23), and a brake (24). The base (22) is fixedly connected to the servo motor (6). The optical axis (23) is fixed on the lower side of the base (15) and is evenly distributed around the lead screw (13). The lower end of the optical axis (23) passes through the base (22) and is slidably connected to the base (22). Each optical axis (23) is fitted with a brake (24), and the brake (24) is fixedly connected to the base (22).

6. A method for press-fitting a fuel pump plunger and an armature, characterized in that, The fuel pump plunger and armature press-fitting device as described in any one of claims 1-5 includes the following steps: S1. Press the oil suction and discharge valve (7) onto the worktable (1) by pressing down the mechanism; S2. The piston rod of the lifting cylinder (4) inside the lifting platform retracts into the cavity (17) and is in the initial position. The distance H1 between the lifting plate (16) on the displacement sensor (26) and the lower surface of the worktable (1) is recorded. S3. The lifting platform drives the lifting rod (3) to rise until the piston (2) inside the oil suction and discharge valve (7) is in contact with the top of the pressurization chamber (9). The distance H2 between the upper lifting plate (16) and the lower surface of the worktable (1) is recorded by the displacement sensor (26). The piston rod of the lifting cylinder (4) is retracted until the upper lifting plate (16) contacts the base (15). S4. The servo motor (6) controls the lead screw (13) to rotate, thereby causing the base (15) to move upward. The upward movement of the base (15) pushes the push rod (3) and the plunger (2) to move upward. At the same time, the reading of the displacement sensor (26) is read. When the reading is H1-H2-Y, the push rod (3) reaches the preset position. Y is the allowable gap between the armature (8) and the sealing ring (10) at the upper end of the plunger hole. S5. The press descends and presses the armature onto the plunger (2). Under pressure, the armature will also descend along the plunger (2) to the sealing ring (10) at the upper end of the armature hole in S4. At this time, the armature is connected to the top of the sealing ring (10) at the upper end of the armature hole, and the armature is sleeved on the plunger (2).

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