An airtightness detection device for the pump body of a fuel injection pump

Abstract

The present invention relates to the technical field of airtightness detection, and particularly relates to an airtightness detection device for the pump body of a fuel injection pump, which comprises a detector main body. A mounting plate is movably connected to the top of the detector main body. A vibration generating device for driving the mounting plate to vibrate is installed on the top of the detector main body. A mounting seat is fixedly installed on the top of the mounting plate. A measuring block is fixedly installed on the top of the mounting seat. A pump housing docked with the measuring block is placed on the top of the mounting seat. A vertical frame is fixedly connected to the top of the mounting plate. A fixing plate is fixedly installed on the top of the vertical frame. A vertically arranged telescopic rod is fixedly connected to the middle of the fixing plate. By restoring the working environment of the injection pump, the detection effect obtained by the present invention is more accurate than direct measurement. Moreover, during continuous detection, continuous detection will not affect each measurement result. After the detection is completed, the pump housing and the shaft sleeve can also be automatically cleaned of the detection oil.

Description

Technical Field

[0001] The present invention relates to the technical field of airtightness detection, and particularly to an airtightness detection device for the pump body of a fuel injection pump. Background Art

[0002] There are multiple oil passages and a shaft hole arranged inside the pump body of the fuel injection pump. A bushing is inserted at the outer end of the shaft hole, and the bushing is tightly fitted with the shaft hole. Since the pump body will be filled with fuel, it is required that there is no air leakage between the outer wall of the bushing and the inner wall of the shaft hole. Therefore, it is necessary to detect the airtightness of the connection surface between the shaft hole of the fuel injection pump body and the bushing.

[0003] The prior art discloses an airtightness detection device for the connection surface between the shaft hole of a fuel injection pump body and a bushing with the publication number of CN110044551A, which includes a sealed cavity. A first sealing ring and a second sealing ring are arranged on the inner wall of one plane of the cavity. The first sealing ring, the second sealing ring, the cavity wall, the pump body, and the bushing jointly enclose a sealed helium-filled space. A helium hole is opened on the cavity wall between the first sealing ring and the second sealing ring, and the helium hole is connected to a helium supply device through a helium pipe. Nitrogen holes, a vacuum pumping hole, and a detection hole are opened on the cavity wall outside the periphery of the second sealing ring. The nitrogen hole is connected to a nitrogen supply device through a nitrogen pipe. The vacuum pumping hole is connected to a vacuum pumping device through a vacuum pumping pipe. The detection hole is connected to a helium detection device through a detection pipe. By filling helium into the helium-filled space, and then detecting whether there is helium in the gas inside the cavity outside the helium-filled space through the helium detection device to determine whether there is air leakage at the connection surface between the bushing and the shaft hole of the pump body.

[0004] During the detection process, it mainly judges whether helium passes through between the shaft hole and the bushing by detecting the content of helium, so as to detect the airtightness. However, during continuous detection, when the pump body is replaced, helium will be released and thus detected. And when the leakage amount is relatively small, the helium detection is inaccurate, resulting in false alarms during continuous detection. Moreover, during the use of the fuel injection pump, the inside of the pump body is filled with fuel, and during operation, it is affected by vibration, a certain temperature, and a certain pressure. This method of directly filling helium into the inside of the pump body to detect airtightness does not represent the airtightness situation of the fuel pump during use, thus leading to inaccurate detection results. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems in the background art, and a proposed airtightness detection device for the pump body of a fuel injection pump is provided.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] An airtightness detection device for the pump body of a fuel injection pump, comprising a detector main body. An installation plate is movably connected to the top of the detector main body. A vibration generating device for driving the installation plate to vibrate is installed on the top of the detector main body. An installation seat is fixedly installed on the top of the installation plate. A measuring block is fixedly installed on the top of the installation seat. A pump housing docked with the measuring block is placed on the top of the installation seat. A vertical frame is fixedly connected to the top of the installation plate. A fixing plate is fixedly installed on the top of the vertical frame. A vertically arranged telescopic rod is fixedly connected to the middle of the fixing plate. The telescopic rod is located directly above the measuring block. A pressing plate is fixedly connected to the lower end of the telescopic rod. A plurality of pressing columns docked with the mounting holes on the pump housing are fixedly connected to the bottom of the pressing plate. A shaft hole is formed inside the pump housing. A shaft sleeve is installed inside the shaft hole. A sealing structure for forming a sealed space between the shaft sleeve and the pump housing is installed on the top of the measuring block. A receiving cavity is formed inside the measuring block. A piston plate is slidably connected to the inner wall of the receiving cavity. The interior of the receiving cavity is divided into two parts, an upper oil storage chamber and a lower air pressure chamber, by the piston plate. A heating structure is installed inside the oil storage chamber. A plurality of communication holes are formed on the top of the measuring block. The communication holes are used to communicate the sealed space with the oil storage chamber. Detection oil is filled inside the oil storage chamber. A plurality of uniformly distributed exhaust devices are also installed on the measuring block. Both ends of the exhaust device are respectively communicated with the sealed space and the air pressure chamber. An air inlet pipe is installed on the installation seat. An air pressure detection device for detecting the air pressure change in the air pressure chamber is installed on the air inlet pipe. One end of the air inlet pipe is communicated with the interior of the air pressure chamber.

[0008] In the above-mentioned airtightness detection device for the pump body of a fuel injection pump, the exhaust device includes an electromagnetic valve. A first communication pipe, a second communication pipe and a third communication pipe are installed on the electromagnetic valve. The electromagnetic valve is communicated with the interior of the air pressure chamber through the provided second communication pipe. The electromagnetic valve is communicated with the interior of the sealed space through the provided first communication pipe. The electromagnetic valve is used to separately control the closing of the first communication pipe, the third communication pipe and the second communication pipe.

[0009] In the above-mentioned airtightness detection device for the pump body of a fuel injection pump, one end of the first communication pipe away from the electromagnetic valve is fixedly connected to a vertically arranged spray head. Two symmetrically distributed inclined grooves are formed on the top of the spray head. A plurality of through holes are formed in the inclined grooves.

[0010] In the above-mentioned airtightness detection device for the pump body of a fuel injection pump, the sealing structure includes an inner sealing gasket and an outer sealing gasket. The inner sealing gasket is in contact with the bottom of the shaft sleeve. The vibration generating device is in contact with the bottom of the pump housing.

[0011] In the above-mentioned airtightness detection device for the pump body of a fuel injection pump, a buffer layer is installed between the detector main body and the mounting plate. Screws are installed on the mounting plate, and the mounting plate is connected to the detector main body through the set screws.

[0012] In the above-mentioned airtightness detection device for the pump body of a fuel injection pump, a buffer pad is fixedly installed between the screw and the mounting plate.

[0013] In the above-mentioned airtightness detection device for the pump body of a fuel injection pump, the vibration generating device includes a motor and a cam structure. The motor drives the cam structure to rotate, and the cam structure contacts the bottom of the mounting plate.

[0014] In the above-mentioned airtightness detection device for the pump body of a fuel injection pump, a plurality of positioning pins corresponding to the mounting holes on the pump housing are fixedly connected to the top of the mounting seat, and a pressing nail corresponding to the mounting hole on the pump housing is fixedly connected to the lower end of the pressing column.

[0015] Compared with the existing technology, the advantages of the airtightness detection device for the pump body of this fuel injection pump are as follows:

[0016] 1. By inflating the inside of the intake pipe, the air pressure detection device is used to detect the air pressure. The gas will push the piston plate upward to squeeze the detection oil. The detection oil flows into the closed space after passing through the communication hole. The heating structure heats the detection oil to simulate the temperature when the injection pump is working. The vibration generating device drives the entire mounting plate to vibrate to restore the vibration when the injection pump is working, and increases the air pressure inside the air pressure chamber. Monitor the change of the air pressure detection device. If the value of the air pressure detection device remains unchanged, it means that there is no air leakage between the pump housing and the shaft sleeve. If the air pressure detection device shows that the air pressure gradually decreases, it means that there is a leakage between the pump housing and the shaft sleeve. This detection device can truly restore the working environment of the injection pump, and the obtained detection effect is more accurate than direct measurement. Moreover, during continuous detection, continuous detection will not affect each measurement result.

[0017] 2. After the detection is completed, the solenoid valve can be used to control the conduction between the second communication pipe and the first communication pipe, so that the compressed air inside the air pressure chamber enters the closed space along the second communication pipe and the first communication pipe to maintain the air pressure balance between the air pressure chamber and the oil storage chamber. The piston plate moves downward, so that the detection oil inside the closed space flows back into the oil storage chamber along the communication hole. And due to the setting of the nozzle, the gas will be sprayed obliquely along the through holes on the inclined groove to blow off the detection oil adhering to the pump housing and the shaft sleeve, so as to realize the reuse of the detection oil and the effect of automatically cleaning the detection oil on the pump housing and the shaft sleeve.

[0018] 3. Due to the setting of the buffer layer and the buffer pad, the mounting plate can compress the buffer layer and the buffer pad, thereby obtaining a certain range of motion, and the cam on the vibration generating device will continuously contact the mounting plate when rotating, so that the buffer layer is stretched and the buffer pad is compressed, and the mounting plate moves upward. When there is no contact, the elasticity of the buffer pad and the buffer layer causes the mounting plate to automatically reset, causing the entire mounting plate to vibrate, simulating the working environment of the jet pump;

[0019] In summary, the present invention restores the working environment of the jet pump, and the detection effect obtained is more accurate than direct measurement. Moreover, during continuous detection, the continuous detection will not affect each measurement result. After the detection is completed, the detection oil on the pump casing and the shaft sleeve can be automatically cleaned. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0021] Figure 2 is a top view of the present invention;

[0022] Figure 3 The present invention Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle;

[0023] Figure 4 It is an enlarged schematic diagram of the structure of the mounting seat of the present invention;

[0024] Figure 5 The present invention Figure 3 A schematic diagram of the structure enlarged at C in the middle;

[0025] Figure 6 It is an enlarged schematic diagram of the structure of the measuring block of the present invention;

[0026] Figure 7 The present invention Figure 6 A schematic diagram of the structure at D in the middle is enlarged;

[0027] Figure 8 is a partial cutaway schematic diagram of a measuring block of the present invention;

[0028] Figure 9 The present invention Figure 2 Schematic diagram of the cross-sectional structure at the middle BB;

[0029] Figure 10 The present invention Figure 9 A schematic diagram of the structure enlarged at E in the middle;

[0030] Figure 11 It is a schematic cross-sectional view of the structure of the solenoid valve of the present invention.

[0031] In the figure: 1, main body of the detector; 2, mounting plate; 3, vibration generating device; 4, mounting seat; 5, measuring block; 6, pump housing; 7, vertical frame; 8, fixing plate; 9, telescopic rod; 10, pressing plate; 11, pressing column; 12, pressing screw; 13, shaft hole; 14, shaft sleeve; 15, sealing structure; 16, accommodating cavity; 17, piston plate; 18, communication hole; 19, intake pipe; 20, air pressure detection device; 21, first communication pipe; 22, solenoid valve; 23, second communication pipe; 24, third communication pipe; 25, heating structure; 26, buffer layer; 27, screw; 28, buffer pad; 29, spray head; 30, through hole; 31, inner sealing pad; 32, outer sealing pad; 33, positioning pin. Detailed implementation manner

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0033] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention 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 should not be construed as a limitation to the present invention.

[0034] Refer to Figures 1-10, An airtightness detection device for the pump body of a fuel injection pump, comprising a detector main body 1. A mounting plate 2 is movably connected to the top of the detector main body 1. A vibration generating device 3 for driving the mounting plate 2 to vibrate is installed on the top of the detector main body 1. A mounting seat 4 is fixedly installed on the top of the mounting plate 2. A measuring block 5 is fixedly installed on the top of the mounting seat 4. A pump housing 6 docked with the measuring block 5 is placed on the top of the mounting seat 4. A vertical frame 7 is fixedly connected to the top of the mounting plate 2. A fixing plate 8 is fixedly installed on the top of the vertical frame 7. A vertically arranged telescopic rod 9 is fixedly connected to the middle of the fixing plate 8. The telescopic rod 9 is located directly above the measuring block 5. A pressing plate 10 is fixedly connected to the lower end of the telescopic rod 9. A plurality of pressing columns 11 docked with the mounting holes on the pump housing 6 are fixedly connected to the bottom of the pressing plate 10. A shaft hole 13 is formed inside the pump housing 6. A shaft sleeve 14 is installed inside the shaft hole 13. A sealing structure 15 for forming a sealed space between the shaft sleeve 14 and the pump housing 6 is installed on the top of the measuring block 5; A receiving cavity 16 is formed inside the measuring block 5. A piston plate 17 is slidably connected to the inner wall of the receiving cavity 16. The interior of the receiving cavity 16 is divided into an upper oil storage chamber and a lower air pressure chamber by the piston plate 17. A heating structure 25 is installed inside the oil storage chamber. A plurality of communication holes 18 are formed on the top of the measuring block 5. The communication holes 18 are used to communicate the sealed space with the oil storage chamber. The interior of the oil storage chamber is filled with detection oil. A plurality of uniformly distributed exhaust devices are also installed on the measuring block 5. Both ends of the exhaust device are respectively communicated with the sealed space and the air pressure chamber. An air inlet pipe 19 is installed on the mounting seat 4. An air pressure detection device 20 for detecting the air pressure change in the air pressure chamber is installed on the air inlet pipe 19. One end of the air inlet pipe 19 is communicated with the interior of the air pressure chamber.

[0035] As a preferred technical solution in this embodiment, the exhaust device includes a solenoid valve 22. The solenoid valve 22 is a three-way solenoid valve. The three passages on the solenoid valve 22 are respectively controlled by three valve bodies for on-off. The three passages on the solenoid valve 22 are respectively installed with a first communication pipe 21, a second communication pipe 23 and a third communication pipe 24. The solenoid valve 22 is communicated with the interior of the air pressure chamber through the provided second communication pipe 23. The solenoid valve 22 is communicated with the interior of the sealed space through the provided first communication pipe 21. The solenoid valve 22 is used to separately control the closing and opening of the first communication pipe 21, the third communication pipe 24 and the second communication pipe 23.

[0036] As a preferred technical solution in this embodiment, the end of the first communication pipe 21 away from the solenoid valve 22 is fixedly connected to a vertically arranged spray head 29. Two symmetrically distributed inclined grooves are formed on the top of the spray head 29. A plurality of through holes 30 are formed on the inclined grooves. The through holes 30 are all perpendicular to the inclined grooves.

[0037] As the preferred technical solution in this embodiment, the sealing structure 15 includes an inner sealing gasket 31 and an outer sealing gasket 32. The inner sealing gasket 31 is in contact with the bottom of the sleeve 14, and the vibration generating device 3 is in contact with the bottom of the pump casing 6. When pressed, a closed space is formed between the measuring block 5, the sleeve 14, and the pump casing 6 through the sealing structure 15.

[0038] As the preferred technical solution in this embodiment, a buffer layer 26 is installed between the detector body 1 and the mounting plate 2, and the buffer layer 26 plays a buffering role. Screws 27 are installed on the mounting plate 2, and the mounting plate 2 is connected to the detector body 1 through the set screws 27. A buffer pad 28 is fixedly installed between the screws 27 and the mounting plate 2, and the buffer pad 28 also plays a buffering role. The vibration generating device 3 includes a motor and a cam structure. The motor drives the cam structure to rotate, and the cam structure contacts the bottom of the mounting plate 2. Due to the setting of the buffer layer 26 and the buffer pad 28, the mounting plate 2 can compress the buffer layer 26 and the buffer pad 28, thereby obtaining a certain range of motion, and the cam on the vibration generating device 3 will continuously contact the mounting plate 2 when rotating, so that the buffer layer 26 is stretched and the buffer pad 28 is compressed, and the mounting plate 2 moves upward. When there is no contact, the elasticity of the buffer pad 28 and the buffer layer 26 makes the mounting plate 2 automatically reset, causing the entire mounting plate 2 to vibrate, simulating the environment when the jet pump is working.

[0039] As the preferred technical solution in this embodiment, the top of the mounting seat 4 is fixedly connected with a plurality of positioning pins 33 corresponding to the mounting holes on the pump casing 6, the lower end of the pressure column 11 is fixedly connected with clamping nails 12 corresponding to the mounting holes on the pump casing 6, the clamping nails 12 at the bottom of the telescopic rod 9 are inserted into the mounting holes of each pump casing 6, and the pump casing 6 is clamped by the clamping nails 12, which can restore the installation state of the pump casing 6 in real conditions, that is, the stress state of the jet pump installed by bolts.

[0040] The working principle and usage method of the present invention are explained as follows: During use, place the pump housing 6 on the mounting base 4 so that the mounting holes on the pump housing 6 are docked with the positioning pins 33 on the mounting base 4. The pump housing 6 is limited by the positioning pins 33. Subsequently, control the telescopic rod 9 to extend, so that the pressing nail 12 at the bottom of the telescopic rod 9 is inserted into the mounting holes of each pump housing 6. The pump housing 6 is pressed by the pressing nail 12, and the state of the pump housing 6 installed in the actual situation can be restored, that is, the state installed by bolts. When pressing, a closed space is formed between the measuring block 5, the bushing 14, and the pump housing 6 through the sealing structure 15. The intake pipe 19 is connected to an air pump, and then inflate the inside of the intake pipe 19. The air pressure detection device 20 is used to detect the air pressure. The gas will push the piston plate 17 to move upward to squeeze the detection oil, and the detection oil flows into the closed space after passing through the communication hole 18. At this time, the solenoid valve 22 controls the conduction between the first communication pipe 21 and the third communication pipe 24, and the gas in the closed space will flow out along the first communication pipe 21 to make the detection oil fill the entire closed space. Subsequently, control the solenoid valve 22 to close completely, and the heating structure 25 heats the detection oil to simulate the temperature when the jet pump works. The vibration generating device 3 drives the entire mounting plate 2 to generate vibration to restore the vibration when the jet pump works. Raise the air pressure inside the air pressure chamber to 0.3-0.5 MPa, and monitor the change of the air pressure detection device 20. If the value of the air pressure detection device 20 remains unchanged, it means that there is no air leakage between the pump housing 6 and the bushing 14. If the air pressure detection device 20 shows that the air pressure gradually decreases, it means that there is a leakage between the pump housing 6 and the bushing 14. This detection device can truly restore the working environment of the jet pump, and the obtained detection effect is more accurate than direct measurement. Moreover, during continuous detection, continuous detection will not affect each measurement result. After the detection is completed, the solenoid valve 22 can be controlled to conduct between the second communication pipe 23 and the first communication pipe 21, so that the compressed air inside the air pressure chamber enters the closed space along the second communication pipe 23 and the first communication pipe 21 to maintain the air pressure balance between the air pressure chamber and the oil storage chamber. The piston plate 17 moves downward, so that the detection oil inside the closed space flows back into the oil storage chamber along the communication hole 18. And due to the setting of the nozzle 29, the gas will be sprayed obliquely along the through holes 30 on the inclined groove to blow off the detection oil adhered to the pump housing 6 and the bushing 14, so as to realize the reuse of the detection oil and the automatic cleaning of the detection oil on the pump housing 6 and the bushing 14.

[0041] Further explanation, the above fixed connection should be understood in a broad sense unless otherwise clearly specified and limited. For example, it can be welding, gluing, or integrally formed setting, etc., which are common means well-known to those skilled in the art.

[0042] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A fuel injection pump body air tightness detection device, characterized in that: The invention comprises a detector body (1), the top of the detector body (1) is movably connected to a mounting plate (2), the top of the detector body (1) is equipped with a vibration generating device (3) for driving the mounting plate (2) to vibrate, the top of the mounting plate (2) is fixedly equipped with a mounting seat (4), the top of the mounting seat (4) is fixedly equipped with a measuring block (5), the top of the mounting seat (4) is provided with a pump housing (6) docking with the measuring block (5), the top of the mounting seat (4) is fixedly connected to a stand (7), the top of the stand (7) is fixedly equipped with a fixing plate (8), the fixing plate (8) is fixedly installed on the top of the fixing plate (8), and the fixing plate (8) is fixedly installed on the top of the fixing plate (8). A vertically arranged telescopic rod (9) is fixedly connected to the middle of the fixed plate (8), the telescopic rod (9) is located directly above the measuring block (5), a pressing plate (10) is fixedly connected to the lower end of the telescopic rod (9), a plurality of pressing columns (11) that are connected to the mounting holes on the pump casing (6) are fixedly connected to the bottom of the pressing plate (10), an axial hole (13) is provided inside the pump casing (6), a shaft sleeve (14) is installed inside the axial hole (13), and a sealing structure (15) for forming a closed space between the shaft sleeve (14) and the pump casing (6) is installed on the top of the measuring block (5); The measuring block (5) is provided with a receiving chamber (16) inside, and the inner wall of the receiving chamber (16) is slidably connected with a piston plate (17). The interior of the receiving chamber (16) is divided into an oil storage chamber and an air pressure chamber by the piston plate (17). A heating structure (25) is installed inside the oil storage chamber. The top of the measuring block (5) is provided with a plurality of connecting holes (18), and the connecting holes (18) are used to connect the closed space with the oil storage chamber. The interior of the oil storage chamber is filled with detection oil. The measuring block (5) is also provided with a plurality of evenly distributed exhaust devices, and the two ends of the exhaust devices are respectively connected to the closed space and the air pressure chamber. The mounting seat (4) is provided with an air intake pipe (19), and an air pressure detection device (20) for detecting the air pressure change in the air pressure chamber is installed on the air intake pipe (19). One end of the air intake pipe (19) is connected to the interior of the air pressure chamber.

2. The pump body air tightness detection device of a fuel injection pump according to claim 1, characterized in that: The exhaust device comprises a solenoid valve (22), on which a first connecting pipe (21), a second connecting pipe (23) and a third connecting pipe (24) are installed; the solenoid valve (22) is connected to the interior of the air pressure chamber through the second connecting pipe (23); the solenoid valve (22) is connected to the interior of the enclosed space through the first connecting pipe (21); and the solenoid valve (22) is used to individually control the closing of the first connecting pipe (21), the third connecting pipe (24) and the second connecting pipe (23).

3. The pump body air tightness detection device of a fuel injection pump according to claim 2, characterized in that: One end of the first connecting pipe (21) away from the solenoid valve (22) is fixedly connected to a vertically arranged nozzle (29), and the top of the nozzle (29) is provided with two symmetrically distributed inclined grooves, and the inclined grooves are provided with a plurality of through holes (30).

4. The pump body air tightness detection device of a fuel injection pump according to claim 1, characterized in that: The sealing structure (15) comprises an inner sealing gasket (31) and an outer sealing gasket (32); the inner sealing gasket (31) is in contact with the bottom of the shaft sleeve (14); and the vibration generating device (3) is in contact with the bottom of the pump housing (6).

5. The pump body air tightness detection device of a fuel injection pump according to claim 1, characterized in that: A buffer layer (26) is installed between the detector body (1) and the mounting plate (2), screws (27) are installed on the mounting plate (2), and the mounting plate (2) is connected to the detector body (1) via the screws (27).

6. The pump body air tightness detection device of a fuel injection pump according to claim 5, characterized in that: A buffer pad (28) is fixedly installed between the screw (27) and the mounting plate (2).

7. The pump body air tightness detection device of a fuel injection pump according to claim 1, characterized in that: The vibration generating device (3) comprises a motor and a cam structure, wherein the motor drives the cam structure to rotate, and the cam structure is in contact with the bottom of the mounting plate (2).

8. The pump body air tightness detection device of a fuel injection pump according to claim 1, characterized in that: The top of the mounting seat (4) is fixedly connected with a plurality of positioning pins (33) corresponding to the mounting holes on the pump housing (6), and the lower end of the pressure column (11) is fixedly connected with a clamping nail (12) corresponding to the mounting holes on the pump housing (6).

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