Motor and surface cleaning device

Abstract

Motor for a surface cleaning device, characterized in that the motor comprises: a base housing in the interior of which a first receiving chamber is formed; a main body of the motor, which is housed in the first receiving chamber and comprises a shaft, a rotor, a stator and a drive switching board, wherein the shaft extends to the outside of the base housing; an impeller, which is connected to the projecting end of the shaft and is arranged to rotate in order to generate an airflow; a wind hood, which surrounds the impeller and is designed to direct the airflow; and a composite bearing, wherein at least one such composite bearing is provided and the composite bearing serves to support the shaft in the base housing, wherein the composite bearing comprises a rotating element, an outer frame, an intermediate roller raceway part, an inner bearing part and an outer bearing part, wherein the rotating element is configured as follows:that it is attached to the shaft and rotates with it, wherein the outer frame is arranged concentrically around the rotating element, wherein the intermediate roller raceway part is located between the rotating element and the outer frame and is designed to rotate freely, wherein the inner bearing part is arranged between the rotating element and the intermediate roller raceway part, wherein the inner bearing part comprises an inner cage and several inner balls embedded in the inner cage, wherein the inner balls roll along the outer raceway on the rotating element and the inner raceway of the intermediate roller raceway part, wherein the outer bearing part is arranged between the intermediate roller raceway part and the outer frame, wherein the outer bearing part comprises an outer cage and several outer balls, wherein the several outer balls are embedded in the interior of the outer cage.wherein the multiple outer balls roll along the outer raceway of the intermediate roller raceway part and the inner raceway of the outer frame; wherein the inner bearing part and the outer bearing part are separated from each other by the intermediate roller raceway part and the inner bearing part and the outer bearing part can rotate independently of each other.

Description

TECHNICAL AREA The invention relates to a motor and a surface cleaning device. TECHNICAL BACKGROUND In surface cleaning equipment, the motor rotor typically needs to run at high speed to drive the impeller and generate sufficient airflow for cleaning. The rotor speed can range from tens of thousands to hundreds of thousands of revolutions per minute. This increased rotor speed depends on roller bearings designed for high-speed operation and on motors equipped with such bearings. The bearing design is engineered to provide efficient rotational support, reduce friction and noise, extend service life, and withstand the demands of a humid cleaning environment.In the field of surface cleaning devices for household appliances, motor design focuses on the use of high-speed, low-loss bearings to support the rotor in order to achieve stable airflow generation and high cleaning performance. DETAILED DESCRIPTION According to the various embodiments set out in this description, a motor and a surface cleaning device are provided. According to one aspect of the present utility model application, a motor for a surface cleaning device is provided, the motor comprising a base housing, a main body, an impeller, a wind hood, and a composite bearing. A first receiving space is formed inside the base housing. The main body of the motor is housed in the first receiving space, the main body comprising a shaft, a rotor, a stator, and a drive circuit board, the shaft extending to the outside of the base housing. The impeller is connected to the projecting end of the shaft and arranged to rotate to generate an airflow. The wind hood is arranged around the impeller and configured to direct the airflow. At least one composite bearing is provided for supporting the shaft in the base housing. The composite bearing comprises a rotating element, an outer frame, an intermediate roller raceway section,an inner bearing part and an outer bearing part; the rotating element is designed to be attached to the shaft and to rotate with it; the outer frame is arranged concentrically around the rotating element; the intermediate roller raceway part is located between the rotating element and the outer frame and is designed to rotate freely; wherein the inner bearing part is arranged between the rotating element and the intermediate roller raceway part; the inner bearing part comprises an inner cage and several inner balls embedded in the inner cage; the inner balls roll along the outer raceway on the rotating element as well as along the inner raceway of the intermediate roller raceway part; wherein the outer bearing part is arranged between the intermediate roller raceway part and the outer frame, the outer bearing part comprising an outer cage and several outer balls.wherein the multiple outer balls are embedded in the interior of the outer cage, wherein the multiple outer balls roll along the outer raceway of the intermediate roller raceway part and the inner raceway of the outer frame; wherein the inner bearing part and the outer bearing part are separated from each other by the intermediate roller raceway part and the inner bearing part and the outer bearing part can rotate independently of each other. In a motor according to an embodiment of the present utility model application, the composite bearing comprises a first composite bearing and a second composite bearing, wherein the first composite bearing and the second composite bearing are arranged separately from each other in the longitudinal direction of the shaft. According to another aspect of the present utility model application, a surface cleaning device is provided which includes the motor described above. DESCRIPTION OF THE DRAWINGS The accompanying drawings show exemplary embodiments of the present utility model application and, together with the description, serve to explain the principle of the present utility model application; they are included for further illustration of the present utility model application and form part of this description. Fig. 1 shows a three-dimensional schematic representation of a high-speed composite bearing according to an embodiment of the present utility model application. Fig. 2 shows an exploded view of a high-speed composite bearing according to an embodiment of the present utility model application. Fig. 3 shows a three-dimensional sectional view of a high-speed composite bearing according to an embodiment of the present utility model application. Fig. 4 shows a three-dimensional sectional view of a motor with an example of such a bearing. SPECIFIC EXECUTION FORMS The present invention will now be explained in more detail with reference to the accompanying drawings and examples. It is understood that the specific examples described here serve only to illustrate the facts and do not constitute a limitation of the present utility model application. Furthermore, it should be noted that, for the sake of simplicity, only the parts relevant to the present invention are shown in the accompanying drawings. It should be noted that the examples in this utility model application and the features contained therein may be combined, provided this does not lead to contradictions. The technical solution of this utility model application is explained in detail below with reference to the attached drawings and by means of examples. Unless otherwise stated, the exemplary embodiments shown are to be understood as examples of various details that demonstrate possibilities for the practical implementation of the technical idea of ​​the present utility model application. Therefore, unless otherwise stated, the features of the various embodiments may be combined, separated, exchanged and / or rearranged as desired within the scope of the technical idea of ​​the present utility model application. The waterproof design of existing floor cleaning machine motors has significant shortcomings. The main problem is that the sealing performance of single-layer labyrinth rings or oil seals is limited, and they cannot effectively prevent liquids from penetrating the motor's interior through gaps between the shaft and the housing. Splashes of water vapor or liquids are unavoidable during floor cleaning machine operation. Conventional waterproof designs are barely able to withstand the continuous or high-pressure ingress of liquids, which can cause electrical components (such as the drive circuit board) to short-circuit or burn out due to moisture. Such failure not only shortens the motor's lifespan but can also lead to equipment downtime and increase maintenance costs.Furthermore, the sealing performance of single-layer waterproof designs decreases further under dynamic operating conditions (e.g., at high shaft speeds), increasing the risk of water vapor ingress. Therefore, there is an urgent need for a motor design that provides robust water protection in high-humidity environments to ensure the safe operation of electrical components while maintaining ease of assembly and cost-effectiveness. The present utility model application relates to a motor for surface cleaning equipment, such as floor cleaning machines, which solves the aforementioned technical problems through a multi-layered water protection structure. The motor comprises a base housing, a main body, an impeller, and a wind hood. Inside the base housing, a first receiving chamber is formed to accommodate the main body. The main body comprises a shaft, a rotor, a stator, and a drive circuit board. The shaft projects from the outside of the base housing and is connected to the impeller to generate an airflow. A watertight sealing structure is provided on the side where the shaft projects from the outside of the base housing.The waterproof sealing structure, with its multi-layered labyrinth design and filling with water-repellent grease, forms a triple protective barrier to prevent liquid from entering the primary receiving chamber. The waterproof sealing structure comprises a double-sided labyrinth ring and a sealing section. The sealing area is formed by the inside of the stationary impeller and the outside of the base housing, creating a first labyrinth structure (the sealing structure between the top of the labyrinth ring and the stationary impeller), a second labyrinth structure (the sealing structure between the bottom of the labyrinth ring and the outside of the base housing), and a third labyrinth structure (the sealing structure between the inner and outer walls of the base housing).Each labyrinth structure lengthens the fluid flow path through staggered protrusions and recesses and is filled with water-repellent grease to improve sealing. This solution, through multi-layered physical barriers and the grease filling, prevents moisture from penetrating the drive circuit board and ensures reliable motor operation in humid environments. The motor of the present utility model application exhibits significantly improved water resistance due to its multi-layered labyrinth structure and filling with water-repellent grease. Tests have shown that it achieves protection class IPX7, meaning the motor can be immersed in 1 meter of water for 30 minutes without sustaining damage. Compared to the single-layer labyrinth rings or oil seals used in previous technology, the present invention effectively prevents the ingress of liquid by means of a triple waterproof barrier, ensures the reliable operation of the aforementioned drive circuit board in environments with high humidity (e.g., when using floor cleaning machines), and extends the service life of the motor.The design with staggered raised and recessed areas lengthens the path of fluid penetration, while the grease filling fills minute gaps and enhances the dynamic sealing effect, thus overcoming the risk of shaft failure inherent in conventional designs. Furthermore, the removable design of the base housing and rear cover simplifies the assembly process and reduces production and maintenance costs. Unlike existing technologies that rely on complex seals or expensive materials, this solution achieves robust water tightness through a simple structure, combining cost-effectiveness with reliability. It is particularly suitable for household and floor cleaning machines and offers significant commercial value. Further aspects of the present utility model application are partly explained below, partly emerge from the description, and partly can be recognized through the practical application of the present utility model application. An embodiment of the present utility model application is described in detail below with reference to the accompanying drawings. The embodiments described in this description and the configurations shown in the accompanying drawings are merely exemplary embodiments of the present utility model application and may be modified in many ways at the time of filing of this application to replace the embodiments and drawings described herein. Furthermore, identical reference numerals or markings in the accompanying drawings denote elements or components that perform essentially the same function. Likewise, the terms used in this description serve to describe the embodiments and are not intended to limit or bind the present invention. Unless the context expressly requires otherwise, the terms "a," "an," and "the" in the singular form also include the plural form.In this text, terms such as "comprises" and "has" are used to indicate the presence of features, quantities, steps, processes, elements, components, or combinations thereof, but do not exclude the presence or addition of one or more other features, elements, steps, processes, components, or combinations thereof. It is understood that, although terms such as "first," "second," "third," etc., may be used in this description to describe various elements, these elements are not limited by these terms. These terms serve only to distinguish one element from another. Thus, for example, without departing from the scope of this utility model application, the first element may be referred to as the second element and the second element as the first element.The term "and / or" encompasses a combination of several relevant elements or any one of the several relevant elements. In the following detailed description, terms such as "front," "back," "left side," and "right side" may be defined by the accompanying drawings, but the shape and position of the components are not limited to these terms. In surface cleaning devices, such as household vacuum cleaners, conventional single-row ball bearings tend to overheat, wear, or cage damage at high speeds due to the high friction between the balls and raceways. This can lead to vibration, noise, or even bearing failure. Particularly in humid cleaning environments, the bearings are subjected to additional stresses, such as moisture ingress, which can further accelerate wear and shorten their lifespan. Furthermore, high-speed operation is often accompanied by high-frequency noise that detracts from the user experience. In existing designs, it is difficult to reconcile the requirements of high speeds and long-term stability with a single-row bearing design, thus limiting the potential for device performance improvements. The present invention provides a high-speed composite bearing that solves the aforementioned problems through an innovative multi-row roller design. The bearing comprises a rotating element, an outer frame, and an intermediate roller raceway section. The intermediate roller raceway section is designed to rotate freely and separates the inner bearing section from the outer bearing section. The inner bearing section contains an inner cage and inner balls that roll along the raceways of the rotating element and the intermediate roller raceway section. The outer bearing section comprises an outer cage and outer balls that roll on the raceways of the intermediate roller raceway section and the outer frame.This design allows independent rotation of the inner and outer bearing sections and divides the high rotational speed into two lower-speed stages, thereby significantly reducing the rotational speed of the balls, frictional heat, and noise. Cover plates on both sides of the outer frame secure the individual components into a single unit, increasing structural stability and providing protection against humid environments. The radially symmetrical intermediate roller raceway distributes the load, and the surface roughness of the raceways is less than 0.2 micrometers, further reducing friction. The present invention also provides a motor incorporating this bearing for shaft support and comprising a base housing, the main body, an impeller, and a wind hood.A single or dual bearing configuration achieves highly efficient rotation and optimal airflow, making it particularly suitable for surface cleaning devices. The advantageous effect of this invention is a significant improvement in the performance and reliability of the motor rotor in surface cleaning equipment. Through the separating action of the intermediate roller raceway, the bearing divides the rotational speed and reduces the relative rotational speed of the inner and outer balls. For example, a rotational speed of 240,000 revolutions per minute is divided into a rolling speed of approximately 120,000 revolutions per minute, the coefficient of friction drops to approximately 0.0008, the temperature rise is limited to below 50 °C, and the wear rate is less than 0.01 mm / 1000 hours. Compared to conventional single-row bearings, the maximum rotational speed increases from 120,000 revolutions per minute to 240,000 revolutions per minute, and the service life is extended from [number] hours to over 500 hours. The cover plate provides IP54 protection, a noise level below 40 dB, and is suitable for humid environments.The balls, aligned perpendicular to the central shaft, and the inner and outer balls with different diameters optimize load distribution, resulting in a vibration acceleration below 0.5 m / s². The motor, with its high-speed bearings, ensures stable shaft support, thereby increasing airflow by approximately 20% and significantly improving the cleaning system's performance. The present invention is characterized by its simple design and low manufacturing costs, offering the combined advantages of high efficiency, long service life, and low noise levels, thus representing a reliable technical solution for surface cleaning equipment. As shown in Fig. 1, the high-speed composite bearing 100 presented here is a multi-row rolling bearing design intended to drive the motor rotor in surface cleaning equipment at high speeds of up to 240,000 revolutions per minute, while simultaneously reducing friction losses, vibrations, and noise, and extending the service life to over 500 hours. By incorporating a freely rotating intermediate roller raceway section 150, the bearing 100 divides the high speed into two lower-speed stages, optimizing load distribution and adapting to the requirements of a wet cleaning environment. As shown in Figures 2 and 3, the bearing 100 has an overall ring-shaped form and comprises a rotating element 110, an inner bearing part 130, an intermediate roller raceway part 150, an outer bearing part 170, and an outer frame 190, which together form a highly efficient and stable rolling bearing system. The relative rolling clearance between the rotating element 110, the inner bearing part 130, the intermediate roller raceway part 150, the outer bearing part 170, and the outer frame 190 ensures power transmission during the relative rotation between the rotating element 110 and the outer frame 190 and reduces friction, thus increasing reliability and durability under high-speed conditions. As shown in Fig. 2, the bearing 100 has a ring-shaped configuration, wherein, from the inside out, the rotary element 110, the inner bearing part 130, the intermediate roller raceway part 150, the outer bearing part 170 and the outer frame 190 are arranged successively; the aforementioned components are arranged coaxially. In conjunction with Figures 1 and 2, using the example of a rotating element 110 driven by a drive element (e.g., the rotor shaft of a motor), the rotating element 110 rotates around the central shaft, its outer raceway 111 rolling relative to the balls 131 of the inner bearing part 130 and, under the influence of the frictional force, causing the inner bearing part 130 to also rotate around the central shaft. The intermediate roller raceway 150 separates the inner bearing part 130 from the outer bearing part 170. The inner raceway 151 and the outer raceway 152 of the intermediate roller raceway 150 transmit the rotational force to the outer bearing part 170. The outer frame 190 remains relatively stationary. The balls 171 of the outer bearing part 170 roll along the inner raceway 191 of the outer frame 190. In some embodiments, the bearing 100 also includes a protective cover 200.The protective cover 200 covers both sides of the outer frame 190 and forms a seal of protection class IP54 to prevent the ingress of dust and liquids. The individual components of the bearing 100 are arranged in an inner-to-outward sequence. The rotating element 110 transmits the torque to the inner bearing part 130. The intermediate roller raceway part 150 distributes the rolling speed. The outer bearing part 170, together with the outer frame 190, stabilizes the load, with the alignment of the raceway and lubrication groove increasing rolling efficiency. The intermediate roller raceway part 150 ensures that the balls 131 and 171 each perform half of the rotation. Under ideal conditions, the limiting speed increases from 120,000 revolutions per minute to 240,000 revolutions per minute compared to conventional single-row bearings, with the overall noise level of the bearing remaining below 40 decibels and the vibration acceleration below 0.5 m / s². In some embodiments, the number of balls is 131 and 171, respectively 7 and 10, with a load-bearing capacity of up to 2000 N. The individual components of the bearing 100 function together in a multi-level manner. The rotating element 110 is driven by a drive element (e.g., the rotor shaft of a motor). The rotating element 110 serves as the starting point for torque transmission, rotates at high speed, and drives the inner bearing part 130 to roll. The inner bearing part 130 engages the raceways of the rotating element 110 and the intermediate roller raceway part 150 via the balls 131, transmits the internal load, and reduces friction, similar to the rolling mechanism of conventional ball bearings. The intermediate roller raceway part 150 serves as a central separating element and is freely rotatable. The intermediate roller raceway part 150 separates the inner bearing part 130 from the outer bearing part 170, distributes the rotational speed, reduces the rolling speed of the balls, and thus overcomes the speed limitation of conventional single-row bearings.The outer bearing element 170 engages with the raceways of the intermediate roller raceway element 150 and the outer frame 190 via balls 171, transmitting the external load and ensuring overall stability. The outer frame 190 serves as a stationary component, attached to the outer casing (e.g., the motor housing), providing structural support, and, together with the protective cover 200, enclosing the individual components into a closed unit. The individual components form a dynamic connection through the rolling action between the raceways and balls. The free rotation of the intermediate roller raceway element 150 enables independent operation of the inner and outer roller elements, thereby significantly increasing the limiting speed and service life. In some embodiments, the drive element of the rotating element 110 is a cylindrical, rigid component with an axial length of approximately 15 mm and a diameter of 10 mm. The outer surface of the rotating element 110 forms the outer raceway 111. The raceway cross-section of the outer raceway 111 is semicircular, with an arc height of 0.5 mm and an arc width of 2.1 mm. The design of the outer raceway 111 follows the geometric principles common in bearing construction and ensures a stable raceway for the balls 131. The rotating element 110 is made of high-strength alloy steel GCr15, has been hardened and tempered, has a hardness of HRC 60-62 and a surface roughness of 0.08-0.1 micrometers, and has been precision polished to reduce frictional resistance. The rotating element 110 is located in the innermost layer of the bearing 100 and is firmly connected to the rotor of the motor via a 2 mm wide keyway or a press fit.The central shaft of the rotating element 110 is coaxial with the entire bearing, with an axial positioning error of less than 0.03 mm. The rotating element 110 is in contact with the balls 131 of the inner bearing part 130 via its outer raceway 111, causing them to roll. The rolling resistance is limited to less than 0.1 N, and the temperature rise caused by friction is below 50 °C. The rolling fit between the rotating element 110 and the inner bearing part 130 forms the internal force transmission path and serves as the starting point for the movement of the entire bearing system. The rigid design of the rotating element 110 and the optimized geometry of the raceways work together to ensure highly efficient torque transmission. The inner bearing part 130 comprises an annular inner cage 132 and seven balls 131. The inner cage 132 has a one-piece structure and features seven mounting holes spaced at equal intervals. The inner cage 132 is made of polyamide PI-66 with a density of 1.4 g / cm³ and a tensile strength of 150 MPa, and is characterized by its low weight and high toughness. The balls 131 are made of silicon carbide ceramic with a hardness of HV1800 and a surface roughness of 0.05 micrometers, which increases wear resistance and high-temperature stability. The inner bearing part 130 is located between the rotating element 110 and the intermediate roller raceway part 150. The balls 131 contact the outer raceway 111 of the rotating element 110 and the inner raceway 151 of the intermediate roller raceway part 150. The center of the cage is aligned coaxially with the rotating element 110, with an axial positioning error of less than 0.02 mm.The balls 131 roll along the outer raceway 111 and the inner raceway 151 at a rolling speed of approximately 120,000 revolutions per minute, withstanding a radial load of 500 N, exhibiting a coefficient of friction of approximately 0.0008, and with a temperature rise limited to 40–50 °C. The inner cage 132, with its flange, limits the axial displacement of the balls 131 to less than 0.01 mm, thus ensuring a stable rolling path. The inner bearing section 130 transmits the torque of the rotating element 110 to the intermediate roller raceway section 150, forming the inner rolling system together with the rotating element 110. The precise fit between the balls and raceways optimizes load transmission efficiency and reduces friction losses. As shown in Fig. 2, the intermediate roller raceway section 150 is an annular component. The inner and outer surfaces of the intermediate roller raceway section 150 each have an inner raceway 151 and an outer raceway 152, respectively. The raceway cross-section of the intermediate roller raceway section 150 is semicircular. The arc height of the inner raceway of the intermediate roller raceway section 150 is 0.5 mm. The arc height of the outer raceway of the intermediate roller raceway section 150 is 0.6 mm. Micro-lubrication grooves are arranged on the surface of the raceways of the intermediate roller raceway section 150. The width of the lubrication grooves is 0.1 mm and the depth is 0.05 mm to improve lubricant distribution. The intermediate roller raceway section 150 is made of high-strength stainless steel SUS440C. The intermediate roller track section 150 is provided with a CVD coating.The coating thickness is 2 micrometers, the surface roughness 0.15–0.2 micrometers, and the hardness HRC 58, which improves wear resistance. The intermediate roller raceway section 150 is positioned between the inner bearing section 130 and the outer bearing section 170. The intermediate roller raceway section 150 is designed to rotate freely. The central shaft of the intermediate roller raceway section 150 is coaxial with the rotating element 110. The radial play of the intermediate roller raceway section 150 is limited to less than 0.01 mm. Due to the free rotation of the intermediate roller raceway section 150, the inner bearing section 130 and the outer bearing section 170 move independently of each other, thus dividing the rotational speed of the rotating element 110 from 240,000 revolutions per minute into two stages. The rolling speed of the balls 171 decreases to approximately 120 rpm.The rotational speed is 000 revolutions per minute, the temperature rise due to frictional heat is below 50 °C, and the wear is less than 0.01 mm / 1000 hours. The inner raceway 151 and the outer raceway 152 of the intermediate roller raceway section 150 each engage with the balls 131 and the balls 171, respectively, transmit a load of 500–1000 N, have a coefficient of friction of 0.0008, and a vibration amplitude of less than 0.02 mm. By separating the inner and outer roller systems, the intermediate roller raceway section 150 optimizes load distribution and, together with the rotating element 110, the inner bearing section 130, and the outer bearing section 170, forms the core of the force distribution and transmission, thereby reducing frictional resistance and improving stability at high speeds. As shown in Fig. 2, the outer bearing part 170 comprises an annular outer cage 172 and 10 balls 171. The outer cage 172 has a one-piece structure and features 10 mounting holes spaced at equal intervals. The diameter of the mounting holes is 2.55 mm. A flange with a height of 0.12 mm is attached to the inner wall of the mounting holes. The balls 171 have a diameter of 2.5 mm and are matched to the larger diameter of the outer raceway. The outer cage 172 is made of polyimide PI-66 with a density of 1.4 g / cm³. The balls 171 are made of silicon carbide ceramic with a hardness of HV 1800 and a surface roughness of 0.05 µm. The outer bearing part 170 is positioned between the intermediate roller raceway part 150 and the outer frame 190. The balls 171 are in contact with the outer track 152 of the intermediate roller track section 150 and with the inner track 191 of the outer ring 190.The center of the outer cage 172 is aligned coaxially with the rotating element 110, with the axial positional tolerance of the outer cage 172 being less than 0.02 mm. The balls 171 roll along the outer raceway 152 at a rolling speed of approximately 120,000 revolutions per minute, withstanding a radial load of 800 N, exhibiting a coefficient of friction of 0.0008, and displaying a vibration acceleration of less than 0.5 m / s². The outer cage 172 limits the axial displacement of the balls 171 by means of a flange. The magnitude of this axial displacement is less than 0.01 mm.The outer bearing part 170 is separated from the inner bearing part 130 by the intermediate roller raceway part 150 and together with the intermediate roller raceway part 150 and the outer frame 190 forms the outer rolling system, which transmits the load stably; the number of balls is reduced compared to the inner side in order to optimize the rolling speed and load adjustment. As shown in Fig. 2, the outer frame 190 is an annular component. The inner raceway 191 is formed on the inside of the outer frame 190. The cross-section of the inner raceway 191 is semicircular. The arc height of the raceway cross-section is 0.6 mm. Lubrication grooves are provided on the surface of the inner raceway 191. The width of the lubrication grooves is 0.1 mm, and the depth is 0.05 mm. The outer frame 190 is made of a high-strength aluminum alloy 7075-T6 with a density of 2.8 g / cm³. The surface of the outer ring 190 is anodized. The thickness of the anodized layer is 20 micrometers and increases corrosion resistance. The outer frame 190 is attached to the engine housing via four M3 threaded holes or dowel pins and serves as a fixed component. The outer frame 190 engages with the balls 171 of the outer bearing part 170 via the inner raceway 191 and accepts a load of 1000 N.Protective covers 200 are attached to both sides of the outer frame 190. These protective covers 200 are ring-shaped, 1 mm thick sheets of SUS304 stainless steel, fastened with six M2 screws. The axial clearance is 0.05 mm, the protection rating is IP54, and the overall noise level of the bearing is below 40 decibels. The protective covers 200 unite the rotating element 110, the intermediate roller raceway section 150, the inner bearing section 130, and the outer bearing section 170 into a single, enclosed unit. Together with the outer bearing section 170, they provide structural support and shielding from the environment, and the design of the lubrication grooves optimizes the rolling efficiency of the balls 171. As shown in Fig. 4, this utility model application proposes a motor. This motor is particularly suitable for household appliances used for surface cleaning. The motor comprises: a wind hood 310, a base housing 320, a main body mounted in the base housing 320, and an impeller 340 mounted inside the wind hood 310. The interior of the base housing 320 is hollow to form a first receiving chamber 321, which allows the main body to be mounted in the base housing 320. The motor includes a rear cover 322. The interior of the base housing 320 is hollow and open at its lower end; the rear cover 322 can be detachably placed onto the lower opening of the base housing 320 to form the first receiving chamber 321. This allows the main body of the motor to be conveniently installed in the base housing 320 after the rear cover 322 has been removed.The main body of the motor comprises a shaft 331, rotatably arranged between the wind hood 310 and the base housing 320, a magnet ring 332, located in the first receiving chamber 321 and attached to the shaft 331, a stator 333, located in the first receiving chamber 321 and surrounding the circumference of the magnet ring 332, and a circuit board (not shown). The shaft 331 is rotatably mounted at both ends of the base housing 320 via bearings 100. In one embodiment, the bearings 100 are arranged distributed along the longitudinal direction of the shaft 331 to rotatably mount the shaft 331 inside the base housing 320. The portion of the shaft 331 extending on the outside of the base housing 320 is connected to the impeller 340. In the present utility model application, the upper end of the shaft 331 projects from the outside of the base housing 320. The upper end of the shaft 331 is externally connected to the impeller 340. The impeller 340 rotates with the rotation of the shaft 331. The wind hood 310 is located on the side of the base housing 320 facing away from the rear cover 322 and encloses the impeller 340. The interior of the wind hood 310 is hollow to form a second receiving chamber 311.The second intake chamber 311 has an inlet opening on the side of the wind hood 310 facing away from the wind hood 310, which is connected to the second intake chamber 311. The second intake chamber 311 has an outlet opening on the side of the wind hood 310 facing away from the rear cover 322, which is also connected to the second intake chamber 311. The impeller 340 is located in the second intake chamber 311. The impeller 340 has an impeller inlet opening and an impeller outlet opening. The impeller inlet opening is connected to the stationary impeller. The impeller outlet opening is connected to the outside air.When the shaft 331 sets the impeller 340 in rotation, air flows through the impeller inlet opening into the second receiving chamber 311 and then flows through the impeller inlet opening to the impeller outlet opening, causing the impeller 340 to create a vacuum in the second receiving chamber 311, which builds up a vacuum in the second receiving chamber 311. The motor also includes a stationary impeller. The stationary impeller serves to control the direction of airflow and to dampen noise. The stationary impeller is detachably mounted on the outside of the top of the base housing 320 and is located inside the wind cowl. To improve the airflow control, the stationary impeller comprises a first stationary impeller 361 and a second stationary impeller 362. The first stationary impeller 361 and the second stationary impeller 362 are fastened to the outside of the top of the base housing 320 by means of screws. One end of the shaft 331 projects outwards from the base housing 320 and passes successively through the second stationary impeller 362, the first stationary impeller 361, and the impeller 340; that is, in the direction from the inlet to the outlet opening, the second stationary impeller 362, the first stationary impeller 361, and the impeller 340 are arranged successively.The wind hood 310 covers the impeller 340 and the first stationary impeller 361 and adjoins the side of the second stationary impeller 362 facing away from the wind hood 310, so that the second stationary impeller 362 and the wind hood 310 together form a second receiving chamber 311. The impeller 340 and the first stationary impeller 361 are located within the second receiving chamber 311. When the impeller 340 rotates, the airflow enters through the inlet opening on the underside of the second stationary impeller, then flows through the first stationary impeller 361 to the impeller 340, is expelled through the outlet opening after passing through the impeller 340, and exits the wind hood 310 onto the outside.By arranging the first stationary impeller 361 and the second stationary impeller 362, the guiding effect for the direction of airflow can be improved, which allows a larger volume of air to be guided per unit of time and increases the air intake capacity of the movable impeller 340. The structural features of the high-speed composite bearing 100 of the present utility model application are comprehensively described in the preceding exemplary description. The separating function of the intermediate roller raceway section 150 enables independent movement of the inner and outer raceways. In conjunction with the optimized design of the raceways and lubrication grooves, the rotational speed of the balls is reduced in stages, thereby minimizing friction losses and vibrations while simultaneously ensuring high rotational speeds and optimizing rotational efficiency and stability. By installing the bearing 100 of the present utility model application in the motor, the current problems regarding the limited service life of single-row bearings and high-frequency noise are solved, effectively increasing the vacuum performance of the motor.Furthermore, the bearing offers the advantages of high performance, high speed, high efficiency, and a compact design. Therefore, surface cleaning devices using this motor can achieve higher suction power, reduce noise, and optimize the user experience within the same amount of time. The foregoing description of the examples in the present utility model application serves only for illustration; it makes no claim to completeness and is not intended to limit the present invention to the precise embodiments disclosed. Those skilled in the field will recognize that numerous modifications and variations are possible based on the foregoing disclosure. Finally, the language used in this description was chosen primarily for readability and illustration and may not serve to define or limit the subject matter of this utility model application. Therefore, the scope of this utility model application should not be limited by this detailed description, but rather by the claims asserted on that basis. The disclosure of the examples in this utility model application thus serves to illustrate, and not to limit, the scope of this utility model application.

Claims

Motor for a surface cleaning device, characterized in that the motor comprises: a base housing in the interior of which a first receiving chamber is formed; a main body of the motor, which is housed in the first receiving chamber and comprises a shaft, a rotor, a stator and a drive switching board, the shaft extending to the outside of the base housing; an impeller connected to the projecting end of the shaft and arranged to rotate in order to generate an airflow; a wind hood surrounding the impeller and designed to direct the airflow; and a composite bearing, wherein at least one such composite bearing is provided and the composite bearing serves to support the shaft in the base housing, the composite bearing comprising a rotating element, an outer frame, an intermediate roller raceway section, an inner bearing section and an outer bearing section, the rotating element being configured as follows:that it is attached to the shaft and rotates with it, wherein the outer frame is arranged concentrically around the rotating element, wherein the intermediate roller raceway part is located between the rotating element and the outer frame and is designed to rotate freely, wherein the inner bearing part is arranged between the rotating element and the intermediate roller raceway part, wherein the inner bearing part comprises an inner cage and several inner balls embedded in the inner cage, wherein the inner balls roll along the outer raceway on the rotating element and the inner raceway of the intermediate roller raceway part, wherein the outer bearing part is arranged between the intermediate roller raceway part and the outer frame, wherein the outer bearing part comprises an outer cage and several outer balls, wherein the several outer balls are embedded in the interior of the outer cage.wherein the multiple outer balls roll along the outer raceway of the intermediate roller raceway part and the inner raceway of the outer frame; wherein the inner bearing part and the outer bearing part are separated from each other by the intermediate roller raceway part and the inner bearing part and the outer bearing part can rotate independently of each other. Motor according to claim 1, characterized in that the composite bearing comprises a first composite bearing and a second composite bearing, wherein the first composite bearing and the second composite bearing are arranged separately from each other in the longitudinal direction of the shaft. Surface cleaning device, characterized in that it comprises a motor according to claim 1 or 2.

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