Variable frequency pump set of car washing platform

Abstract

The invention discloses a variable frequency pump set of a car washing platform, and relates to the technical field of pump sets. The system specifically comprises multiple sets of variable lift pumps arranged in parallel, inlets of the multiple variable lift pumps are connected to a water source, and outlets of the multiple variable lift pumps are connected to a car washing spray gun module through a one-way valve and a first opening and closing valve; the car washing platform variable frequency pump set further comprises a data acquisition module which is electrically connected with the car washing spray gun module. On one hand, the multiple sets of variable lift pumps connected in parallel are arranged, the total flow can be controlled by starting and stopping different numbers of variable lift pumps, meanwhile, the total lift is controlled by controlling the lift of the started variable lift pumps, and therefore the different starting and stopping numbers and starting mode working conditions of the whole car washing spray gun module can be met; on the other hand, through mutual cooperation of the data acquisition module, the central processing module, the control module and the like, automatic matching of the pump set output and the working condition of the car washing spray gun module can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of strength testing, and in particular to a variable frequency pump group for a car wash platform. Background Art

[0002] The car wash platform is used to clean the vehicle. It uses a water pump to pump water to the car wash spray gun, and uses the water flow to rinse and clean the vehicle.

[0003] The car wash spray gun has multi-mode adjustment functions, such as low-pressure and high-flow flushing mode, high-pressure and low-flow vertex flushing and dust removal mode, and high-pressure and high-flow large-scale stubborn stain flushing mode.

[0004] In the prior art, the water pump for car washing is a single-group fixed design (with a fixed number of impeller stages). However, due to the different modes of the car washing spray guns, the required head is different. For example, the head and flow required in the dust or foam washing stage are relatively low, while high head and high flow are required for cleaning stains with strong adhesion. The head span in these two modes is large, and the output parameters of a single-group water pump with a fixed number of impeller stages cannot be adjusted within this range. At the same time, since the car washing platform will connect multiple car washing spray guns in parallel, the upper and lower limits of the head and flow provided by the water pump will be further increased when the starting number and starting mode of the car washing spray guns are different. The service life of the single-group fixed design is greatly reduced under such a large-span head and flow output.

[0005] To this end, the present invention proposes a variable frequency pump group for a car washing platform. Summary of the Invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a variable frequency pump group for a car washing platform.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A variable frequency pump set for a car wash platform includes multiple sets of variable lift pumps arranged in parallel, wherein the inlets of the multiple variable lift pumps are connected to a water source, and the outlets of the multiple variable lift pumps are connected to a car wash spray gun module via a one-way valve and an on-off valve; The car wash platform variable frequency pump group also includes: A data acquisition module is electrically connected to the car wash spray gun module and is used to collect the opening and closing signals and mode signals of the car wash spray gun module; A central processing module, which is connected to the data acquisition module and is used to analyze the information collected by the data acquisition module; The control module is connected to the variable lift pump control, receives the control instructions from the central processing module and controls the start and stop and output parameters of the variable lift pump according to the control instructions.

[0008] Preferably: the variable lift pump includes a mounting seat, a drive motor and a multi-stage pump head assembly, the multi-stage pump head assembly is arranged on the top outer wall of the mounting seat, the drive motor is connected to the top outer wall of the mounting seat through a linear displacement mechanism, and the multi-stage pump head assembly and the output shaft of the drive motor are matched through a coupling assembly.

[0009] Furthermore: the multi-stage pump head assembly is composed of multiple pump casings and an impeller assembly rotatably connected to the inner wall of the pump casing. The pump casing is fixed to the mounting seat through a mounting frame. The two adjacent pump casings are fixed and connected through a connecting casing, and the side wall of the pump casing located on the water inlet side is fixed and connected to the water inlet casing. The axes of the multiple impeller assemblies are equipped with the same main shaft through a clutch transmission assembly. The side walls of the connecting casing and the side walls of the pump casing at the very end are welded and connected to a water channel. The other end of the water channel is connected to the second opening and closing valve, and the other end of the second opening and closing valve is connected to the same multi-way pipe.

[0010] On the basis of the above scheme: the multi-way pipe is connected to the car washing spray gun module, the water inlet shell is connected to the water source, and the main shaft is driven and matched with the output shaft of the drive motor through the coupling assembly.

[0011] A better solution among the above solutions is that: the connecting shell is conical, and the diameter of the connecting shell connected to the upper-level pump shell is larger than the diameter of the connecting shell connected to the lower-level pump shell.

[0012] As a further solution of the present invention: the impeller assembly includes a rear cover plate and a front cover plate located on both sides and a centrifugal blade located in the middle, the side wall of the front cover plate is welded with a hub, and a wear-resistant ring is provided at the fitting position of the hub and the pump casing, the rear cover plate is rotatably connected to the outer wall of the main shaft, and the outer walls of the main shaft on both sides of the rear cover plate are provided with limit rings for axially limiting the rear cover plate.

[0013] At the same time, the clutch transmission assembly includes a plurality of transmission grooves in a circular array opened on the inner wall of the rear cover plate and a plurality of transmission claws radially connected to the inner wall of the main shaft and cooperating with the transmission grooves. The transmission claws are connected to the inner wall of the main shaft through springs.

[0014] As a preferred embodiment of the present invention: the inner wall of the main shaft is axially slidably fitted with a core shaft, the inner side of the transmission claw is provided with a second inclined surface, and the outer wall of the core shaft is provided with a plurality of first inclined surfaces fitted with spring limiters.

[0015] At the same time, the coupling assembly consists of two end face pawls that cooperate with each other, and the two end face pawls are respectively fixed to the output shaft end of the drive motor and the end of the main shaft, and the end face pawl connected to the output shaft end of the drive motor is fixedly connected to the end of the core shaft.

[0016] As a better solution of the present invention: the linear displacement mechanism includes a guide rod, a screw rod, and a motor, the guide rod is fixed to the inner wall of the mounting seat, the screw rod is rotatably connected to the inner wall of the mounting seat, the bottom outer wall of the driving motor is fixed with a base by bolts, the base is slidably connected to the outer wall of the guide rod and is connected to the outer wall of the screw rod by threads, the motor is fixed to the side wall of the mounting seat by bolts, and the output shaft of the motor is connected to the end of the screw rod by a coupling.

[0017] The beneficial effects of the present invention are: 1. The present invention, on the one hand, by setting up multiple groups of variable lift pumps in parallel, can control the total flow rate by using different numbers of variable lift pumps to start and stop, and at the same time control the head of the opened variable lift pumps to control the total head, so as to match the different starting and closing numbers and starting mode working conditions of the entire car wash spray gun module, thereby increasing the car washing effect and increasing the upper and lower limit spans of the entire pump group output. On the other hand, through the mutual cooperation of the data acquisition module, the central processing module, the control module, etc., the pump group output can be automatically matched with the working conditions of the car wash spray gun module, thereby increasing the service life.

[0018] 2. The present invention sets up multiple sets of pump casings and impeller assemblies in series, and controls the coordination between the impeller assembly and the main shaft transmission and the opening and closing passage of the opening and closing valve 2 through the clutch transmission assembly, so that the working stages can be conveniently controlled on the basis of increasing the maximum output head by multi-stage setting, thereby controlling the output head.

[0019] 3. The present invention, by providing a connecting shell with a conical design and arranging the water channel at the connecting shell, can increase the water pressure by reducing the cross-sectional area, thereby achieving the amplification of the lift. At the same time, the conical connecting shell diameter design can also ensure that when entering the next-stage impeller assembly, the water source can enter close to the axis of the impeller assembly, thereby increasing the impeller assembly's energy-enhancing path for the water source and improving energy efficiency.

[0020] 4. The present invention, based on multi-stage adjustability, sets a clutch transmission assembly. On the one hand, it can ensure that the other impeller assemblies will not idle when the output is not at full head, which has a certain energy-saving effect. On the other hand, it uses the cooperation between the transmission claw and the transmission groove to achieve clutch, uses the cooperation between the first and second ramps to achieve the position drive of the transmission claw, and then uses the movement of the core shaft to achieve the cooperation drive between the first and second ramps. In the end, it can achieve convenient adjustment of different levels of use by using only the simple linear drive of the linear displacement mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the piping architecture of a variable frequency pump unit for a car wash platform proposed by the present invention; Figure 2 This is a circuit diagram of a variable frequency pump unit for a car wash platform proposed by the present invention; Figure 3 This is a schematic diagram of the overall structure of a variable lift pump of a variable frequency pump group for a car wash platform proposed by the present invention; Figure 4 This is a structural diagram of a variable lift pump multi-stage pump head assembly of a car wash platform variable frequency pump unit proposed by the present invention; Figure 5 This is a structural schematic diagram of a variable lift pump impeller assembly of a variable frequency pump set for a car wash platform proposed by the present invention; Figure 6 This is a schematic diagram of the variable lift pump limit ring structure of a variable frequency pump group for a car wash platform proposed by the present invention; Figure 7 Schematic diagram of the variable lift pump clutch transmission assembly structure of a car wash platform variable frequency pump group proposed by the present invention Figure 1 ; Figure 8 Schematic diagram of the variable lift pump clutch transmission assembly structure of a car wash platform variable frequency pump group proposed by the present invention Figure 2 ; Figure 9 This is a structural diagram of a variable lift pump coupling assembly of a variable frequency pump set for a car wash platform proposed by the present invention; Figure 10 This is a schematic diagram of the structure of the variable lift pump linear displacement mechanism of the variable frequency pump group for a car wash platform proposed by the present invention.

[0022] In the figure: 1. Mounting seat; 2. Linear displacement mechanism; 3. Drive motor; 4. Coupling assembly; 5. Multi-stage pump head assembly; 6. Connecting shell; 7. Mounting frame; 8. Pump shell; 9. Water inlet shell; 10. Main shaft; 11. Mechanical seal; 12. Impeller assembly; 13. Water channel; 14. Opening and closing valve 2; 15. Multi-way pipe; 16. Rear cover; 17. Centrifugal blades; 18. Front cover; 19. Wear-resistant ring; 20. Hub; 21. Limiting ring; 22. Transmission claw; 23. Transmission groove; 24. Spring; 25. Core shaft; 26. Inclined surface 1; 27. Inclined surface 2; 28. End face ratchet; 29. ​​Guide rod; 30. Screw; 31. Base; 32. Motor. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be further described in detail below in conjunction with specific implementation methods.

[0024] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0025] Example 1: A variable frequency pump set for a car wash platform, such as Figures 1-10 As shown, it includes multiple groups of variable lift pumps arranged in parallel, the inlets of the multiple variable lift pumps are connected to the water source, and the outlets of the multiple variable lift pumps are connected to the car washing gun module through a one-way valve and an opening and closing valve.

[0026] The car wash platform variable frequency pump group also includes: A data acquisition module is electrically connected to the car wash spray gun module and is used to collect the opening and closing signals and mode signals of the car wash spray gun module; A central processing module, which is connected to the data acquisition module and is used to analyze the information collected by the data acquisition module; The control module is connected to the variable lift pump control, receives the control instructions from the central processing module and controls the start and stop and output parameters of the variable lift pump according to the control instructions.

[0027] When this device is in use, the variable lift pump can transport water from the water source to the car wash spray gun module for car washing, and during the car washing process, the data acquisition module collects the opening and closing information and mode information of the car wash spray gun module in real time, and transmits the collected information to the central processing module. The central processing module analyzes the data to generate control instructions and sends them to the control module. The control module controls the opening and closing number and output parameters of the variable lift pump so that they correspond to the total flow and lift required by the car wash spray gun module.

[0028] Moreover, this embodiment does not limit the installation form and installation location of the data acquisition module, central processing module, and control module. They can be installed according to needs, for example, all of them can be integrated into a control box, and the control box can be installed in a car wash room with a variable lift pump or a car wash platform.

[0029] On the one hand, this device, by setting up multiple groups of variable head pumps in parallel, can control the total flow by using different numbers of variable head pumps to start and stop, and at the same time control the head of the open variable head pumps to control the total head, so as to match the different starting and closing numbers and starting mode working conditions of the entire car wash spray gun module, thereby increasing the car washing effect and increasing the upper and lower limit spans of the entire pump group output. On the other hand, through the mutual cooperation of the data acquisition module, the central processing module, the control module, etc., the pump group output can be automatically matched with the working conditions of the car wash spray gun module, thereby increasing the service life.

[0030] Example 2: A variable frequency pump set for a car wash platform, such as Figure 3-10 As shown, in order to solve the adjustment problem; this embodiment makes the following improvements on the basis of Example 1: the variable lift pump includes a mounting base 1, a drive motor 3 and a multi-stage pump head assembly 5, the multi-stage pump head assembly 5 is arranged on the top outer wall of the mounting base 1, the drive motor 3 is connected to the top outer wall of the mounting base 1 through a linear displacement mechanism 2, and the multi-stage pump head assembly 5 and the output shaft of the drive motor 3 are matched through a coupling assembly 4.

[0031] The multi-stage pump head assembly 5 is composed of multiple pump casings 8 and an impeller assembly 12 rotatably connected to the inner wall of the pump casing 8. The pump casing 8 is fixed to the mounting base 1 through the mounting frame 7. The two adjacent pump casings 8 are fixed and connected through the connecting casing 6, and the side wall of the pump casing 8 located on the water inlet side is fixed and connected to the water inlet casing 9. The axes of the multiple impeller assemblies 12 are equipped with the same main shaft 10 through the clutch transmission assembly. The side walls of the connecting casing 6 and the side walls of the pump casing 8 located at the end are welded and connected to the water channel 13. The other end of the water channel 13 is connected to the opening and closing valve 2 14, and the other end of the opening and closing valve 2 14 is connected to the same multi-way pipe 15.

[0032] The multi-way pipe 15 is connected to the car washing spray gun module, the water inlet shell 9 is connected to the water source, and the main shaft 10 is driven and matched with the output shaft of the drive motor 3 through the coupling assembly 4.

[0033] A mechanical seal 11 is provided at the fitting position between the main shaft 10 and the pump housing 8 .

[0034] The connecting shell 6 is conical, and the diameter of the connecting shell 6 connected to the upper-stage pump shell 8 is larger than the diameter of the connecting shell 6 connected to the lower-stage pump shell 8.

[0035] When the drive motor 3 is started, it can drive the main shaft 10 to rotate through the coupling assembly 4, thereby driving the impeller assembly 12 to rotate through the clutch transmission assembly. When the impeller assembly 12 rotates, it can throw the water source outward through the action of centrifugal force to increase kinetic energy. At the same time, the inner side of the impeller assembly 12 generates negative pressure to suck new water source along the axis. When adjusting the head, if a higher head is required, the on-off valve 2 14 of the previous level is closed and the on-off valve 2 14 of the next level is opened at the same time. At the same time, the clutch transmission assembly is used to increase the number of impeller assemblies 12 that cooperate with the main shaft 10. At this time, the water that has increased the kinetic energy by centrifugation through the impeller assembly 12 of the previous level will enter the impeller assembly 12 of the next level through the connecting shell 6 again and centrifugally increase the kinetic energy again, thereby increasing the head step by step.

[0036] The specific operation is to number the impeller assembly 12 and the opening and closing valve 14 as a, b, c, d...; A, B, C, D... according to the length from the water inlet shell 9 from small to large. Under the minimum head working condition, the impeller assembly 12 numbered a is matched with the main shaft 10, while the other impeller assemblies 12 are not matched. At the same time, only and only the opening and closing valve 14 numbered A is opened, and the rest are closed. At this time, the water flows through an impeller assembly 12 for centrifugal energization and is transported to the car wash spray gun module through the multi-way pipe 15. If the head needs to be increased, the opening and closing valve 14 numbered A is closed, and the opening and closing valve 14 numbered B is opened. At the same time, the impeller assemblies 12 numbered a and b are matched with the main shaft 10. At this time, the water source enters the impeller assembly 12 numbered b through the connecting shell 6 after energization after the impeller assembly 12 numbered a, and is discharged after energization again.

[0037] This device is provided with multiple sets of pump casings 8 and impeller assemblies 12 in series, and controls the transmission coordination between the impeller assembly 12 and the main shaft 10 and the opening and closing passage control of the opening and closing valve 2 14 through the clutch transmission assembly. In this way, on the basis of increasing the maximum output head by multi-stage setting, the working stage number can be conveniently controlled, thereby controlling the output head.

[0038] In addition, the device is provided with a connecting shell 6, through its conical design, and the water channel 13 is arranged at the connecting shell 6, so that the water pressure can be increased by reducing the cross-sectional area, thereby achieving the amplification of the head. At the same time, the conical connecting shell 6 diameter design can also ensure that when entering the next-stage impeller assembly 12, the water source can enter close to the axis of the impeller assembly 12, thereby enabling the impeller assembly 12 to increase the water source energy-increasing path and improve energy efficiency.

[0039] In order to solve transmission control problems such as Figure 5-10 As shown: the impeller assembly 12 includes a rear cover plate 16 and a front cover plate 18 on both sides and a centrifugal blade 17 in the middle. The side wall of the front cover plate 18 is welded with a hub 20, and a wear-resistant ring 19 is provided at the fitting position between the hub 20 and the pump casing 8; the water flows into the gap between the rear cover plate 16 and the front cover plate 18 from the hub 20, and is then driven to rotate by the rotating centrifugal blades 17, and then moves outward by centrifugal force.

[0040] The rear cover plate 16 is rotatably connected to the outer wall of the main shaft 10 , and the outer walls of the main shaft 10 on both sides of the rear cover plate 16 are provided with limiting rings 21 for axially limiting the rear cover plate 16 .

[0041] The clutch transmission assembly includes a plurality of transmission grooves 23 formed in a circular array on the inner wall of the rear cover plate 16 and a plurality of transmission claws 22 radially connected to the inner wall of the main shaft 10 and cooperating with the transmission grooves 23. The transmission claws 22 are connected to the inner wall of the main shaft 10 via springs 24.

[0042] The inner wall of the main shaft 10 is axially slidably fitted with a core shaft 25 , the inner side of the transmission claw 22 is provided with a second inclined surface 27 , and the outer wall of the core shaft 25 is provided with a plurality of first inclined surfaces 26 that are limitedly fitted with the spring 24 .

[0043] When the core shaft 25 moves axially, the transmission claw 22 can be moved outward through the cooperation of the inclined surface 1 26 and the inclined surface 27, so that the transmission claw 22 is matched with the transmission groove 23, and the main shaft 10 and the rear cover plate 16 are in transmission cooperation. When the inclined surface 1 26 and the inclined surface 27 are not limited, the transmission claw 22 is contracted by the elastic force of the transmission groove 23, and the main shaft 10 and the rear cover plate 16 are not in transmission cooperation.

[0044] At the same time, the adjustment process is as follows: in the minimum head state, such as Figure 8As shown, at this time, the inclined surface 1 26 closest to the water inlet shell 9 cooperates with the inclined surface 2 27, and the inclined surface 1 26 pushes the inclined surface 2 27 outward, while the inclined surface 1 26 of the next stage just contacts the inclined surface 2 27 and does not push the inclined surface 2 27 outward. At the same time, there is a spacing between the inclined surfaces 1 26 and the inclined surfaces 2 27 of the subsequent stages, and the spacing increases successively. When the required lift increases, the core shaft 25 moves axially. At this time, the inclined surface 1 26 of the initial stage is still in the state of pushing up the inclined surface 2 27, and at the same time, the inclined surface 1 26 of the next stage further cooperates with the inclined surface 2 27 to push out the inclined surface 2 27, and the inclined surface 1 26 of the next stage is just in the state of just contacting with the inclined surface 2 27. There is a gap between the remaining inclined surfaces 1 26 and the inclined surface 2 27. According to this process, until all the inclined surfaces 1 26 limit and lift the inclined surface 2 27, the maximum lift output is achieved.

[0045] The coupling assembly 4 consists of two end face pawls 28 that cooperate with each other. The two end face pawls 28 are respectively fixed to the output shaft end of the drive motor 3 and the end of the main shaft 10, and the end face pawl 28 connected to the output shaft end of the drive motor 3 is fixedly connected to the end of the core shaft 25.

[0046] The linear displacement mechanism 2 includes a guide rod 29, a screw rod 30, and a motor 32. The guide rod 29 is fixed to the inner wall of the mounting base 1, and the screw rod 30 is rotatably connected to the inner wall of the mounting base 1. The bottom outer wall of the driving motor 3 is fixed with a base 31 by bolts. The base 31 is slidably connected to the outer wall of the guide rod 29 and is connected to the outer wall of the screw rod 30 by threads. The motor 32 is fixed to the side wall of the mounting base 1 by bolts, and the output shaft of the motor 32 is connected to the end of the screw rod 30 through a coupling.

[0047] When the motor 32 is started, it can drive the screw rod 30 to rotate, thereby driving the drive motor 3 to move through the action of the thread, and thus driving the core shaft 25 to move through the end face pawl 28.

[0048] This device, based on multi-stage adjustment, is provided with a clutch transmission component. On the one hand, it can ensure that the remaining impeller components 12 will not idle when the output is not at full head, which has a certain energy-saving effect. On the other hand, the clutch is realized by the cooperation between the transmission claw 22 and the transmission groove 23, and the position drive of the transmission claw 22 is realized by the cooperation between the inclined plane 1 26 and the inclined plane 2 27. The coordinated drive of the inclined plane 1 26 and the inclined plane 2 27 is then realized by the movement of the core shaft 25. In this way, the convenient adjustment of different levels of use can be achieved by only using the simple linear drive of the linear displacement mechanism 2.

[0049] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A variable frequency pump unit for a car wash platform, comprising a plurality of variable lift pumps arranged in parallel, wherein the inlets of the plurality of variable lift pumps are connected to a water source, and the outlets of the plurality of variable lift pumps are connected to a car wash spray gun module via a one-way valve and an on-off valve, characterized in that: The car wash platform variable frequency pump group also includes: A data acquisition module is electrically connected to the car wash spray gun module and is used to collect the opening and closing signals and mode signals of the car wash spray gun module; A central processing module, which is connected to the data acquisition module and is used to analyze the information collected by the data acquisition module; The control module is connected to the variable lift pump control, receives the control instructions from the central processing module and controls the start and stop and output parameters of the variable lift pump according to the control instructions.

2. A variable frequency pump unit for a car wash platform according to claim 1, characterized in that: The variable lift pump comprises a mounting seat (1), a drive motor (3) and a multi-stage pump head assembly (5), wherein the multi-stage pump head assembly (5) is arranged on the top outer wall of the mounting seat (1), the drive motor (3) is connected to the top outer wall of the mounting seat (1) through a linear displacement mechanism (2), and the multi-stage pump head assembly (5) and the output shaft of the drive motor (3) are matched through a coupling assembly (4).

3. A variable frequency pump unit for a car wash platform according to claim 2, characterized in that: The multi-stage pump head assembly (5) is composed of a plurality of pump casings (8) and an impeller assembly (12) rotatably connected to the inner wall of the pump casing (8). The pump casing (8) is fixed to the mounting seat (1) through a mounting frame (7). Two adjacent pump casings (8) are fixed and connected through a connecting casing (6), and the side wall of the pump casing (8) located on the water inlet side is fixed and connected to the water inlet casing (9). The axes of the plurality of impeller assemblies (12) are connected to the same main shaft (10) through a clutch transmission assembly. The side walls of the connecting casing (6) and the side wall of the pump casing (8) located at the end are welded and connected to a water channel (13). The other end of the water channel (13) is connected to a second on-off valve (14), and the other end of the second on-off valve (14) is connected to the same multi-way pipe (15).

4. A variable frequency pump unit for a car wash platform according to claim 3, characterized in that: The multi-way pipe (15) is connected to the car washing spray gun module, the water inlet housing (9) is connected to the water source, and the main shaft (10) is driven and matched with the output shaft of the drive motor (3) through the coupling assembly (4).

5. A variable frequency pump unit for a car wash platform according to claim 3, characterized in that: The connecting shell (6) is conical, and the diameter of the connecting shell (6) connected to the upper-stage pump shell (8) is larger than the diameter of the connecting shell (6) connected to the lower-stage pump shell (8).

6. A variable frequency pump unit for a car wash platform according to claim 3, characterized in that: The impeller assembly (12) comprises a rear cover plate (16) and a front cover plate (18) located on both sides and a centrifugal blade (17) located in the middle. A hub (20) is welded to the side wall of the front cover plate (18), and a wear-resistant ring (19) is provided at the joint between the hub (20) and the pump housing (8). The rear cover plate (16) is rotatably connected to the outer wall of the main shaft (10), and the outer walls of the main shaft (10) located on both sides of the rear cover plate (16) are provided with a limiting ring (21) for axially limiting the rear cover plate (16).

7. A variable frequency pump unit for a car wash platform according to claim 6, characterized in that: The clutch transmission assembly comprises a plurality of transmission grooves (23) formed in a circular array on the inner wall of the rear cover plate (16) and a plurality of transmission claws (22) radially slidably connected to the inner wall of the main shaft (10) and cooperating with the transmission grooves (23), wherein the transmission claws (22) are connected to the inner wall of the main shaft (10) via springs (24).

8. A variable frequency pump unit for a car wash platform according to claim 7, characterized in that: The inner wall of the main shaft (10) is axially slidably fitted with a core shaft (25), the inner side of the transmission claw (22) is provided with a second inclined surface (27), and the outer wall of the core shaft (25) is provided with a plurality of first inclined surfaces (26) that are limitedly fitted with the spring (24).

9. A variable frequency pump unit for a car wash platform according to claim 8, characterized in that: The coupling assembly (4) is composed of two end face pawls (28) that cooperate with each other. The two end face pawls (28) are respectively fixed to the output shaft end of the drive motor (3) and the end of the main shaft (10), and the end face pawl (28) connected to the output shaft end of the drive motor (3) is fixedly connected to the end of the core shaft (25).

10. A variable frequency pump unit for a car wash platform according to claim 9, characterized in that: The linear displacement mechanism (2) comprises a guide rod (29), a screw rod (30), and a motor (32), wherein the guide rod (29) is fixed to the inner wall of the mounting seat (1), the screw rod (30) is rotatably connected to the inner wall of the mounting seat (1), the bottom outer wall of the driving motor (3) is fixed with a base (31) by bolts, the base (31) is slidably connected to the outer wall of the guide rod (29) and is connected to the outer wall of the screw rod (30) by threads, the motor (32) is fixed to the side wall of the mounting seat (1) by bolts, and the output shaft of the motor (32) is connected to the end of the screw rod (30) by a coupling.

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