Swimming pool water flow paddle direct drive motor

Abstract

The invention discloses a swimming pool water flow paddle direct-drive motor, which comprises an end cover, a motor shaft, a rotor, a base, a stator and a sealing unit, and is characterized in that the direct-drive motor is horizontally arranged in water in a swimming pool, the motor shaft is fixedly connected with a water flow paddle shaft and directly drives a water flow paddle, and the working voltage of the direct-drive motor does not exceed 36V and is within a human body safety voltage range; the sealing unit comprises a rack, an oil seal, an oil flinger and lubricating oil, the lower side of the oil flinger is soaked in the lubricating oil, and when the oil flinger rotates along with the motor shaft, the lubricating oil in the cavity is splashed to the contact face of a lip of the oil seal and the motor shaft. The water flow paddle is directly driven, and the driving efficiency is high; the oil flinger is arranged between the two oil seals, so that dry friction between the oil seals and a motor shaft is changed into oil film friction, and the service life of the oil seals is greatly prolonged; the framework insulation is adopted to realize automatic winding of the winding, so that the large-scale and consistency guarantee of products is facilitated; and the motor is a low-voltage motor, so that the personal safety in case of electric leakage is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of motors, and in particular to a direct-drive motor for an underwater water flow paddle in a small swimming pool. Background Art

[0002] With the improvement of living standards and the development of rehabilitation technology, swimming has become an important and common sport, and is loved by many people. However, swimming pools have become a key constraint on this sport. In this case, private small swimming pools have emerged, and many families or institutions in Europe and the United States have been equipped with them. Private small swimming pools have a variety of sizes, such as 2×3 meters, 3×5 meters, etc., but they are much smaller than public swimming pools. Private small swimming pools are made of fiberglass container basins, and water paddles form a water flow with a corresponding flow rate. The human body is placed in a small swimming pool to simulate swimming movements, generating a reverse force of the water flow, thereby ensuring that the body will not move with the water flow.

[0003] The existing small swimming pool water paddles are almost all driven by industrial motors + reduction gearboxes, and the motors and reduction gearboxes are located outside the pool container basin, and are driven by belts or chains, which has the disadvantages of occupying a large space and low system efficiency. Solving the shortcomings of the existing technology can improve the acceptance of end users and expand the promotion scope of private small swimming pools. Summary of the invention

[0004] In order to solve the problem that the above-mentioned existing small swimming pool water flow paddle is driven by a motor + reduction box, and the motor and the reduction box are arranged outside the swimming pool, driven by belt or chain, occupying a large space and having low system efficiency, the present invention provides a swimming pool water flow paddle direct-drive motor, which directly drives the water flow paddle by sleeve-fixing the motor shaft and the water flow paddle shaft, and has high driving efficiency; the sealing unit is provided with two oil seals, and an oil-slinging plate is provided in the middle, so that the dry friction between the oil seal and the motor shaft is converted into oil film friction, which greatly improves the sealing performance and the service life of the oil seal; the winding is wound by enameled copper wire on the skeleton insulation using automated equipment, and the use of automated equipment is conducive to product scale and consistency assurance, and can also improve winding efficiency and reduce motor cost, and a plurality of conical teeth for sleeve winding are provided inside the stator core, which improves the working efficiency of winding sleeve connection.

[0005] To achieve the above-mentioned purpose, the present invention provides a swimming pool water paddle direct-drive motor, including an end cover, a motor shaft, a rotor, a base, a stator and a sealing unit, wherein the motor shaft sleeve is arranged at the center of the base, the rotor is fixedly connected to the motor shaft, the stator is fixedly connected to the base, the end cover is arranged in two pieces, which are respectively arranged at the left and right ends of the base, the sealing unit is provided with two pieces, which are respectively arranged between the inner hole wall of the end covers at both ends and the outer cylindrical surface of the motor shaft, the direct-drive motor is horizontally arranged in the water in the swimming pool, the motor shaft is fixedly connected to the water paddle shaft, and directly drives the water paddle, the working voltage of the direct-drive motor does not exceed 36V, and the speed of the direct-drive motor does not exceed 300rpm within the safe voltage range of the human body; the sealing unit includes a frame, an oil seal, an oil slinger and lubricating oil, the frame sealing sleeve is arranged in the center hole of the end cover, and a A first through hole, wherein the left and right sides of the first through hole are provided with layer holes which are symmetrically arranged on the left and right sides, the oil seal is provided with two pieces, the two oil seals are respectively sleeved in the two layer holes, the lips of the oil seal are connected with the outer cylindrical surface of the motor shaft by interference fit, the two oil seals are arranged back to back, so that a chamber is formed between the two oil seals, the inner wall of the first through hole and the outer cylindrical surface of the motor shaft, the lubricating oil is arranged in the chamber, the oil level is 5mm lower than the lowest busbar of the motor shaft, the oil-slinging plate is sleeved in the first through hole, the inner hole of the oil-slinging plate is connected with the motor shaft by interference fit, the interference amount is set to 0.04-0.08mm, the lower side of the oil-slinging plate is immersed in the lubricating oil, and when the oil-slinging plate rotates with the motor shaft, the lubricating oil in the chamber will be splashed onto the contact surface between the lip of the oil seal and the motor shaft, so that the dry friction between the lip of the oil seal and the motor shaft is changed into oil film friction.

[0006] As a further improvement of the present technology, the stator includes a stator core, a winding and a slot wedge. The stator core is composed of a plurality of stacked electrical silicon steel punching sheets. The punching sheet is an integrated structure with a plurality of circumferentially evenly distributed conical teeth inside. The conical teeth are provided with symmetrically arranged dovetail grooves on both sides of the tooth ends. The winding is provided with a plurality of windings, the number of which is consistent with the number of conical teeth. The winding is sleeved on the outside of the conical teeth. The slot wedge is provided with inclined surfaces matching the dovetail grooves on both sides. The slot wedge is clamped in the dovetail grooves facing each other between two adjacent conical teeth through the inclined surfaces on both sides, which is used to limit the winding.

[0007] As a further improvement of the present technology, the winding is wound on a skeleton insulation, and the skeleton insulation adopts modified nylon or high temperature and heat resistant plastic PEEK, and the wall thickness of the skeleton insulation is set to 0.3-0.8 mm.

[0008] As a further improvement of the present technology, the taper of the conical teeth is set to 5 to 10 degrees. As a further improvement of the present technology, the oil-slinging plate is provided with 2N L-shaped oil passage holes evenly distributed in a circle, wherein N is a natural number greater than 1, and the L-shaped oil passage holes are composed of radial holes arranged on the outer circumferential surface of the oil-slinging plate, and axial holes connected to the radial holes and the other end of which passes through the end face of one side of the oil-slinging plate. The 2N L-shaped oil passage holes are divided into two groups, one group of N L-shaped oil passage holes passes through one side of the oil-slinging plate, and the other group of N L-shaped oil passage holes passes through the other side of the oil-slinging plate, and the two groups of L-shaped oil passage holes are staggered. The L-shaped oil passage holes on the lower side of the oil-slinging plate are immersed in lubricating oil. When the oil-slinging plate rotates with the motor shaft, the L-shaped oil passage holes will bring up the lubricating oil from the axial holes to splash onto the contact surface between the lip of the oil seal and the motor shaft.

[0009] As a further improvement of the present technology, a plurality of first heat dissipation holes are provided near the outer circular surface of the base, which are parallel to the axis of the base, evenly distributed in a circle and pass through the two end surfaces. The first heat dissipation holes are arc-shaped waist holes, and second heat dissipation holes are provided at positions corresponding to the first heat dissipation holes on the end covers at both ends. The second heat dissipation holes are consistent in shape with the first heat dissipation holes, and the outer peripheries are 0.5 to 1 mm larger than the outer peripheries of the corresponding first heat dissipation holes. The first heat dissipation holes and the second heat dissipation holes are immersed in the water in the swimming pool to dissipate heat for the direct-drive motor.

[0010] As a further improvement of the present technology, a wavy groove is provided on the near-axial side of the first heat dissipation hole.

[0011] As a further improvement of the present technology, the base, end cover and frame are all made of aluminum alloy; the motor shaft is made of 304 stainless steel; and the lubricating oil is food-grade lubricating oil.

[0012] As a further improvement of the present technology, the motor shaft is a hollow shaft with a first keyway, the water flow paddle shaft is provided with a second keyway matching the first keyway, the first keyway and the second keyway are provided with flat keys, the motor shaft sleeve is arranged on the water flow paddle shaft and is fixedly connected by a flat key.

[0013] As a further improvement of the present technology, when the power required by the swimming pool water flow paddle is greater than the power of the direct drive motor, multiple direct drive motors can be connected in series on the water flow paddle shaft, so that the direct drive motor can be suitable for the functional requirements of swimming pools in various power ranges.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention directly drives the water flow paddle by sleeve-connecting and fixing the motor shaft with the water flow paddle shaft, and the driving efficiency is high; 2. The sealing unit of the present invention is provided with two oil seals arranged facing each other, and an oil-slinging plate is arranged between the two oil seals, so that the dry friction between the oil seal and the motor shaft is changed into oil film friction, which greatly improves the sealing performance and the service life of the oil seal; 3. In the prior art, the winding on the integrated stator core is generally wound directly on the internal teeth of the stator core. The winding equipment has a complex structure and a complex winding process. The winding must be inlaid, and the inlay must avoid scratching the wire, which leads to low production efficiency. The winding of the present invention is made of enameled copper wire on the skeleton insulation using automated equipment. The winding process is simple. The use of automated equipment is conducive to product scale and consistency assurance, and can also improve winding efficiency and reduce the cost of direct-drive motors. 4. The stator core of the present invention is provided with a plurality of conical teeth for sleeve windings, which greatly improves the efficiency of sleeve windings compared with the rectangular teeth in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a half-section structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the sealing unit structure of an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an oil-slinging pan according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the base and stator according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the stator core structure of an embodiment of the present invention; Figure 6 Schematic diagram of winding structure according to an embodiment of the present invention; Figure 7 Schematic diagram of the structure of tapered teeth and slots inside the stator core according to an embodiment of the present invention; Figure 8 It is a schematic diagram of the external structure of an embodiment of the present invention.

[0016] In the figure: 1, end cover, 11, second heat dissipation hole, 2, motor shaft, 21, first keyway, 3, rotor, 4, base, 41, first heat dissipation hole, 5, stator, 51, stator core, 511, tapered teeth, 5111, dovetail groove, 52, winding, 53, slot wedge, 531, inclined surface, 54, skeleton insulation, 6, sealing unit, 61, frame, 611, first through hole, 612, layer hole, 62, oil seal, 63, oil throwing plate, 631, L-shaped oil passage hole, 64, lubricating oil, 65, chamber. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] like Figure 1 , Figure 2 As shown, an embodiment of the present invention includes an end cover 1, a motor shaft 2, a rotor 3, a base 4, a stator 5 and a sealing unit 6. The motor shaft 2 is sleeved in the center of the base 4, the rotor 3 is fixedly connected to the motor shaft 2, the stator 5 is fixedly connected to the base 4, the end cover 1 is provided in two pieces, which are respectively provided at the left and right ends of the base 4, the sealing unit 6 is provided in two pieces, which are respectively provided between the inner hole wall of the end cover 1 at both ends and the outer cylindrical surface of the motor shaft 2, the direct drive motor is horizontally arranged in the water in the swimming pool, the motor shaft 2 is fixedly connected to the water flow paddle shaft, and the water flow paddle is directly driven, the working voltage of the direct drive motor does not exceed 36V, and the speed of the direct drive motor does not exceed 300rpm within the safe voltage range of the human body; the sealing unit 6 includes a frame 61, an oil seal 62, an oil thrower 63 and a lubricating oil 64, the frame 61 sealing sleeve is provided in the center hole of the end cover 1, a first through hole 611 is provided in the middle, and layer holes 612 which are symmetrically arranged on the left and right sides of the first through hole 611 are provided, and the oil seal 62 is provided There are two pieces, and the two oil seals 62 are respectively sleeved in the two layer holes 612. The lips of the oil seals 62 are connected with the outer cylindrical surface of the motor shaft 2 by interference fit. The two oil seals 62 are arranged back to back, so that a chamber 65 is formed between the two oil seals 62, the inner cylindrical surface of the first through hole 611 and the outer cylindrical surface of the motor shaft 2. The lubricating oil 64 is arranged in the chamber 65, and the oil level is lower than the lowest busbar H of the motor shaft 2 by 5mm. The oil slinger 63 is sleeved on the outer side of the motor shaft 2 in the first through hole 611, and the oil slinger The inner hole of the oil pan 63 is connected with the motor shaft 2 by interference fit, and the interference is set to 0.04-0.08mm. The lower side of the oil pan 63 is immersed in the lubricating oil 64. When the oil pan 63 rotates with the motor shaft 2, the lubricating oil 64 in the chamber 65 is splashed onto the contact surface between the lip of the oil seal 62 and the motor shaft 2, so that the dry friction between the lip of the oil seal 62 and the motor shaft 2 is converted into oil film friction, which greatly improves the sealing performance of the motor and the service life of the oil seal 62.

[0019] like Figure 4 , Figure 5 , Figure 7 As shown, the stator 5 includes a stator core 51, a winding 52 and a slot wedge 53. The stator core 51 is composed of a plurality of stacked electrical silicon steel punching sheets. The punching sheet is an integrated structure with a plurality of circumferentially evenly distributed conical teeth 511 arranged inside. The tooth ends of the conical teeth 511 are provided with symmetrically arranged dovetail grooves 5111 on both sides. The winding 52 is provided with a plurality of windings, the number of which is consistent with the number of conical teeth 511. The winding 52 is sleeved on the outside of the conical teeth 511. The slot wedge 53 is provided with inclined surfaces 531 matching the dovetail grooves 5111 on both sides. The slot wedge 53 is clamped in the dovetail grooves 5111 facing each other between two adjacent conical teeth 511 through the inclined surfaces on both sides, so as to limit the winding 52.

[0020] The teeth on the existing iron core are generally set as rectangular teeth with parallel two sides. Compared with the rectangular teeth, the setting of the conical teeth 511 in this patent is conducive to the socketing of the winding 52 and the conical teeth 511, thereby improving the production efficiency of the direct drive motor.

[0021] like Figure 6 As shown, the winding 52 is wound on the skeleton insulation 54. The skeleton insulation 54 is made of modified nylon or high temperature and heat resistant plastic PEEK. The wall thickness of the skeleton insulation 54 is set to 0.3-0.8 mm.

[0022] The winding 52 is made of enameled copper wire wound on the skeleton insulation 54 using automated equipment. The use of automated equipment is conducive to product scale and consistency assurance, while also improving the winding production efficiency and reducing the cost of the direct drive motor.

[0023] As a preference, the taper α of the tapered teeth is set to 5 to 10° (e.g. Figure 5 , Figure 7 as shown).

[0024] As a preference, Figure 3 As shown, the oil-slinging plate 63 is provided with 60 L-shaped oil passage holes 631 uniformly distributed in a circle, and the L-shaped oil passage holes 631 are composed of radial holes arranged on the outer circumferential surface of the oil-slinging plate 63, and axial holes connected with the radial holes and the other end of which penetrates through the end surface of one side of the oil-slinging plate 63. The 60 L-shaped oil passage holes 631 are divided into two groups, one group of 30 L-shaped oil passage holes 631 penetrates through one side of the oil-slinging plate 63, and the other group of 30 L-shaped oil passage holes 631 penetrates through the other side of the oil-slinging plate 63, and the two groups of L-shaped oil passage holes 631 are staggered. The L-shaped oil passage holes 631 on the lower side of the oil-slinging plate are immersed in the lubricating oil 64. When the oil-slinging plate 63 rotates with the motor shaft 2, the L-shaped oil passage holes 631 will bring up the lubricating oil 64 from the axial holes to splash onto the contact surface between the lip of the oil seal 62 and the motor shaft 2, thereby forming an oil film on the contact surface, thereby improving the friction life of the lip.

[0025] As a preference, Figure 4 , Figure 8 As shown, a plurality of first heat dissipation holes 41 are provided near the outer circumferential surface of the base 4, which are parallel to the axis of the base, uniformly distributed in a circle and penetrate through the two end surfaces. The first heat dissipation holes 41 are arc-shaped waist holes. Second heat dissipation holes 11 are provided at positions corresponding to the first heat dissipation holes 41 on the end covers 1 at both ends. The second heat dissipation holes 11 have the same shape as the first heat dissipation holes 41, and the outer peripheries are 0.5 to 1 mm larger than the outer peripheries of the corresponding first heat dissipation holes 41. The first heat dissipation holes 41 and the second heat dissipation holes 11 are immersed in the water in the swimming pool to dissipate heat for the direct-drive motor.

[0026] The provision of the first heat dissipation hole 41 and the second heat dissipation hole 11 increases the heat exchange area between the direct drive motor and the swimming pool water, can reduce the temperature rise of the direct drive motor winding 52, reduce the material consumption of the base 4 and the end cover 1, and reduce the cost.

[0027] As a preference, Figure 4 As shown, a wavy groove is provided on the near-axial side of the first heat dissipation hole 41. The provision of the wavy groove can further increase the heat exchange area with the swimming pool water and improve the heat dissipation performance.

[0028] Preferably, the base 4, the end cover 1 and the frame 61 are all made of aluminum alloy to meet the requirements of corrosion protection and lightweight for underwater use; the motor shaft 2 is made of 304 stainless steel; the lubricating oil 64 is food-grade lubricating oil to avoid safety accidents caused by leakage of the lubricating oil 64.

[0029] As a preference, Figure 8 As shown, the motor shaft 2 is a hollow shaft with a first keyway 21, and the water flow paddle shaft is provided with a second keyway matching the first keyway 21. Flat keys are provided in the first keyway 21 and the second keyway. The motor shaft 2 is sleeved on the water flow paddle shaft and fixedly connected by flat keys.

[0030] Preferably, when the power required by the swimming pool water flow paddle is greater than the power of the direct drive motor, multiple direct drive motors can be connected in series on the water flow paddle shaft so that the direct drive motor can be suitable for the functional requirements of swimming pools in various power ranges.

[0031] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A swimming pool water paddle direct drive motor, comprising an end cover, a motor shaft, a rotor, a base, a stator and a sealing unit, wherein the motor shaft sleeve is arranged at the center of the base, the rotor is fixedly connected to the motor shaft, the stator is fixedly connected to the base, the end cover is provided in two pieces, respectively arranged at the left and right ends of the base, the sealing unit is provided in two pieces, respectively arranged between the inner hole wall of the end cover at both ends and the outer cylindrical surface of the motor shaft, characterized in that: The direct-drive motor is horizontally arranged in the water of the swimming pool, the motor shaft is fixedly connected to the water paddle shaft, and directly drives the water paddle. The working voltage of the direct-drive motor does not exceed 36V. Within the safe voltage range of the human body, the speed of the direct-drive motor does not exceed 300rpm; the sealing unit includes a frame, an oil seal, an oil-slinging plate and lubricating oil. The frame sealing sleeve is arranged in the center hole of the end cover, and a first through hole is arranged in the middle. The left and right sides of the first through hole are provided with layer holes arranged symmetrically on the left and right sides. The oil seal is provided with two pieces, and the two oil seals are respectively sleeved in the two layer holes. The lip of the oil seal is connected with the outer cylindrical surface of the motor shaft by interference fit. Then, the two oil seals are arranged back to back to form a chamber between the two oil seals, the inner wall of the first through hole and the outer cylindrical surface of the motor shaft. The lubricating oil is arranged in the chamber, and the oil level is 5 mm lower than the lowest busbar of the motor shaft. The oil-slinging plate is sleeved in the first through hole, and the inner hole of the oil-slinging plate is connected with the motor shaft by interference fit, and the interference is set to 0.04-0.08 mm. The lower side of the oil-slinging plate is immersed in the lubricating oil. When the oil-slinging plate rotates with the motor shaft, the lubricating oil in the chamber is splashed onto the contact surface between the lip of the oil seal and the motor shaft, so that the dry friction between the lip of the oil seal and the motor shaft is changed into oil film friction.

2. A swimming pool water current paddle direct drive motor according to claim 1, characterized in that: The stator includes a stator core, a winding and a slot wedge. The stator core is composed of a plurality of stacked electrical silicon steel punching sheets. The punching sheet is an integrated structure with a plurality of circumferentially evenly distributed conical teeth arranged inside. The conical teeth are provided with symmetrically arranged dovetail grooves on both sides of the tooth ends. The winding is provided with a plurality of windings, the number of which is consistent with the number of conical teeth. The winding is sleeved on the outside of the conical teeth. The slot wedge is provided with inclined surfaces matching the dovetail grooves on both sides. The slot wedge is clamped in the dovetail grooves facing each other between two adjacent conical teeth through the inclined surfaces on both sides, so as to limit the winding.

3. A swimming pool water current paddle direct drive motor according to claim 2, characterized in that: The winding is wound on the skeleton insulation, and the skeleton insulation adopts modified nylon or high temperature and heat resistant plastic PEEK, and the wall thickness of the skeleton insulation is set to 0.3-0.8mm.

4. A swimming pool water current paddle direct drive motor according to claim 2, characterized in that: The taper of the conical teeth is set to 5-10 degrees.

5. A swimming pool water current paddle direct drive motor according to claim 1, characterized in that: The oil-slinging plate is provided with 2N L-shaped oil passage holes evenly distributed in a circle, wherein N is a natural number greater than 1, and the L-shaped oil passage holes are composed of radial holes arranged on the outer circumferential surface of the oil-slinging plate, and axial holes connected with the radial holes and the other end of which passes through the end surface of one side of the oil-slinging plate. The 2N L-shaped oil passage holes are divided into two groups, one group of N L-shaped oil passage holes passes through one side of the oil-slinging plate, and the other group of N L-shaped oil passage holes passes through the other side of the oil-slinging plate, and the two groups of L-shaped oil passage holes are staggered. The L-shaped oil passage holes on the lower side of the oil-slinging plate are immersed in lubricating oil. When the oil-slinging plate rotates with the motor shaft, the L-shaped oil passage holes will bring up the lubricating oil from the axial holes to splash onto the contact surface between the lip of the oil seal and the motor shaft.

6. A swimming pool water paddle direct drive motor according to claim 1, characterized in that: The base is provided with a plurality of first heat dissipation holes parallel to the base axis, evenly distributed circumferentially and penetrating the two end surfaces near the outer circular surface. The first heat dissipation holes are arc-shaped waist holes. Second heat dissipation holes are provided on the end covers at both ends at positions corresponding to the first heat dissipation holes. The second heat dissipation holes are consistent in shape with the first heat dissipation holes, and the outer peripheries are 0.5 to 1 mm larger than the outer peripheries of the corresponding first heat dissipation holes. The first heat dissipation holes and the second heat dissipation holes are immersed in the water in the swimming pool to dissipate heat for the direct-drive motor.

7. A swimming pool water current paddle direct drive motor according to claim 6, characterized in that: A wave-shaped groove is provided on the near-axial side surface of the first heat dissipation hole.

8. A swimming pool water current paddle direct drive motor according to claim 1, characterized in that: The base, end cover and frame are all made of aluminum alloy; the motor shaft is made of 304 stainless steel; and the lubricating oil is food-grade lubricating oil.

9. A swimming pool water current paddle direct drive motor according to claim 1, characterized in that: The motor shaft is a hollow shaft with a first keyway, the water flow paddle shaft is provided with a second keyway matching the first keyway, the first keyway and the second keyway are provided with flat keys, the motor shaft sleeve is arranged on the water flow paddle shaft and is fixedly connected by the flat key.

10. A swimming pool water current paddle direct drive motor according to claim 1, characterized in that: When the power required by the swimming pool water flow paddle is greater than the power of the direct drive motor, multiple direct drive motors can be connected in series on the water flow paddle shaft, so that the direct drive motor can be suitable for the functional requirements of swimming pools in various power ranges.

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