Patent Description:
A fluid transfer pump driven by an electric motor transfers water or other fluids from one position to another by means of a pump unit. An inlet of the pump can be connected to a fluid source such as a water pool via an input pipe. An outlet of the pump can be connected to a discharge pipe such as a standard garden hose to transfer a discharged fluid to a desired position. A type of fluid transfer pump performs the suction and discharge of the fluid by the rotation of an impeller.

The fluid transfer pump is typically connected to a power supply through an electric wire. In recent years, a battery-powered fluid transfer pump is emerging. The battery-powered fluid transfer pump is popular with users due to its portability. However, this cordless pump has some shortcomings, such as a large size, a heavy weight, a complex structure, a short battery life, and a low heat dissipation efficiency of the electric motor.

US patent application publication no. <CIT> describes a transfer pump for displacing fluid and may generally include a housing, a pump including an impeller, the pump being disposed within the housing for creating suction to draw the fluid through the impeller, a motor for driving the pump, a battery operable to power the motor, and a sensor for sensing current drawn by the motor.

International patent application publication no. <CIT> describes a high-pressure cleaning machine and an assembly thereof, the high-pressure cleaning machine comprising a housing and a functional unit, comprising an electric motor arranged in the housing and a pump for delivering a water flow outwards. The high-pressure cleaning machine can be electrically connected to a battery pack the battery pack.

Thus, it is necessary to develop a portable fluid transfer pump having a compact structure, with ease of assembly, a prolonged battery life, and improved heat dissipation performance.

To achieve the above objective, the present invention provides a fluid transfer pump. The fluid transfer pump comprises: a housing, a pump unit, an electric motor assembly, a power supply mounting base, and a speed change mechanism, wherein the pump unit comprises an impeller; the electric motor assembly is used to drive the impeller to rotate around an axis of the impeller; the power supply mounting base is used to receive a power supply for supplying electricity to the pump unit; and the speed change mechanism is arranged between the pump unit and the electric motor assembly, wherein an internal space of the housing can be divided into a plurality of areas by at least one separator; the electric motor assembly comprises an electric motor, and a fan driven by the electric motor and adjacent to one end of the electric motor; and the fan and the other end of the electric motor are respectively located in different areas.

Preferably, the power supply mounting base is arranged in a power supply compartment; the pump unit, the speed change mechanism, the electric motor assembly, and the power supply compartment are successively arrayed in an extension direction of the axis of the impeller; and the power supply can be guided into the power supply compartment in a mounting direction. Viewed from a side, an axis in the mounting direction is inclined at an angle relative to the axis of the impeller.

The speed change mechanism may be configured to reduce a rotation speed between the electric motor assembly and the impeller. Preferably, the speed change mechanism can comprise a gearbox shell as well as a gear and a ring gear which are meshed with each other and accommodated in the gearbox shell; and the gear is in drive connection with an output shaft of the electric motor assembly, and the ring gear is in drive connection with a drive shaft of the impeller. In one embodiment, the ring gear comprises a main ring gear body on which inner teeth are formed as well as a ring gear extension part extending axially from the main ring gear body, and the ring gear extension part matches the drive shaft of the impeller. A first bearing can be disposed around the ring gear extension part. The ring gear can comprise a ring gear shaft which defines a rotational axis of the ring gear; a bearing seat is formed in the ring gear; and a second bearing disposed around the ring gear shaft is accommodated in the bearing seat. The ring gear can comprise a transition part connecting the main ring gear body to the ring gear extension part, and at least one part of the bearing seat is formed in the transition part. The gearbox shell can be fixed to a mounting flange located at one end of the housing of the pump unit.

In one aspect, the power supply compartment can comprise a compartment shell and a cover pivotally connected to the compartment shell; the cover has a first sealing edge, and the compartment shell has a second sealing edge aligned to the first sealing edge; and a groove used to accommodate at least one part of a sealing component is formed in at least one of the first sealing edge and the second sealing edge. Preferably, at least one of the first sealing edge and the second sealing edge has a ridge part extending outward; and when the cover is in a closed position, the ridge part abuts against the sealing component.

In one aspect, the fluid transfer pump can comprise a locking component used to lock the cover in the closed position; the locking component is able to move between a locked position and an unlocked position; and when the locking component is in the locked position, at least one part of the locking component presses against the first sealing edge of the cover. Preferably, the compartment shell comprises a protrusion part extending from the second sealing edge, the locking component is held on the protrusion part through a biasing component, and the biasing component applies a biasing force to the locking component to resist movement of the locking component away from the protrusion part.

Preferably, the fan is located in a first area, the first area is at least partially defined by a first wall part of the housing, and a first opening is formed in the first wall part such that the first area communicates with an external environment. Preferably, the first opening is radially aligned to the fan. The other end of the electric motor is located in a second area, the second area is at least partially defined by a second wall part of the housing, and a second opening is formed in the second wall part such that the second area communicates with the external environment. Preferably, the second opening is located above the electric motor. The first area and the second area are separated by a first partition plate extending from an inner wall of the housing, and the first partition plate is in a close fit with a first sealing ring disposed around the electric motor assembly. The pump unit is located in a third area, and the third area and the first area are separated by a second partition plate extending from the inner wall of the housing. The second partition plate is in a close fit with the second sealing ring disposed around the gearbox shell.

In one aspect, the fluid transfer pump can comprise a base; the base has support parts and an elevation part elevated relative to bottom surfaces of the support parts; and a hole via which an internal space of the housing communicates with the external environment is formed in at least one of the support parts and the elevation part. Preferably, the elevation part is located below the electric motor assembly, the elevation part comprises a bottom wall and a baffle plate located on an inner side of the bottom wall, the hole is formed in the bottom wall, and a tortuous path from the hole to the internal space of the housing is defined by the baffle plate.

<FIG> shows a fluid transfer pump, which is used to pump a fluid such as water, according to an embodiment of the present invention. The fluid transfer pump comprises a housing <NUM> and a pump unit <NUM> accommodated in the housing <NUM>. The pump unit comprises a fluid inlet <NUM> used to be connected to an input pipe and a fluid outlet <NUM> used to be connected to a discharge pipe. In this embodiment, the pump unit <NUM> is arranged at a front part (a left side in <FIG>) of the housing <NUM>, and the fluid inlet <NUM> and the fluid outlet <NUM> respectively extend from two sides of the housing <NUM>. In other embodiments, the pump unit <NUM> may be arranged at other positions in the housing. The fluid inlet <NUM> and the fluid outlet <NUM> may be arranged in an upper side, a front end, or a rear end of the housing. A base <NUM> stably supports the fluid transfer pump on the ground or other supporting surfaces. The base <NUM> can be integrated with the housing <NUM> or be independent of the housing.

The fluid transfer pump shown in <FIG> can be powered by a portable power supply. The portable power supply can be a lithium battery and is removably mounted on the fluid transfer pump. In the illustrated embodiment, the fluid transfer pump comprises a power supply compartment <NUM> located at a rear part (a right side in <FIG>) of the housing <NUM>, and a power supply for supplying electricity to the pump unit <NUM> is accommodated in the power supply compartment <NUM>. The fluid transfer pump further comprises a handle <NUM> for a user to grasp. The handle <NUM> can be located above the housing <NUM> and connected to the front part and rear part of the housing <NUM>. As shown in <FIG>, one end of the handle <NUM> is adjacent to the fluid inlet <NUM> and the fluid outlet <NUM>, and the other end of the handle is adjacent to the power supply compartment <NUM>.

The handle <NUM> can be integrated with the housing <NUM> or be mounted on the housing <NUM> as an independent component. The handle <NUM> comprises a grasping part, the size and contour of which conform to a palm of the user. The grasping part can be covered with an elastic material such as rubber, which is deformable when the grasping part is grasped by the user, so as to improve grasping comfort. At least one part of the grasping part can be covered with pits or ridges to prevent the handle from slipping out of a hand of the user. Preferably, when the fluid transfer pump is put onto the ground, the grasping part of the handle <NUM> intersects a vertical line passing through the center of gravity of the whole fluid transfer pump. The position of the grasping part is conducive to saving the force required by the user to lift the fluid transfer pump and relieving shaking of the fluid transfer pump during movement.

An operating unit used to control the fluid transfer pump can be arranged on the handle <NUM>. <FIG> shows a button <NUM>. The button is located at a front part of the handle <NUM>, such that a thumb of the user can naturally touch the button <NUM> when the user grasps the handle <NUM>. In addition, a control key <NUM> and a status indicator <NUM> can be arranged on the housing <NUM>. In an embodiment, the button <NUM> is used to start and stop the fluid transfer pump, and the control key <NUM> allows the user to adjust the power and/or speed of an electric motor, or to set an operating time of the electric motor. The state indicator <NUM> can include a plurality of LED lights <NUM> or other types of display devices which are used to display the current power and/or speed level, or continuous operating time and remaining operating time of the pump unit, and other information. In other embodiments, the handle <NUM> and/or the housing <NUM> may be provided with a control and display unit such as a locking button, a pumping mode switching button, a timer button, and an electronic display screen to assist the user in operating the fluid transfer pump.

<FIG> shows one side of the fluid transfer pump. In this embodiment, the housing <NUM> is formed by assembling two half housings. In order to clearly show an internal structure, one of the half housings has been removed. The pump unit <NUM> and the power supply compartment <NUM> are respectively located on two sides of the housing <NUM>, and an electric motor assembly <NUM> used to drive the pump unit <NUM> to operate is located between the pump unit <NUM> and the power supply compartment <NUM> and is approximately in the middle of the whole housing <NUM>. Such a configuration can enable the power supply compartment <NUM> to be furthest away from a fluid source. A speed change mechanism <NUM> is arranged between the pump unit <NUM> and the electric motor assembly <NUM>, and is used to change an output rotation speed of the electric motor assembly <NUM>. An impeller in the pump unit <NUM> is in drive connection with an output end of the speed change mechanism <NUM>, and is driven by the electric motor assembly <NUM> and the speed change mechanism <NUM> to rotate along an axis L1 of the impeller. It can be seen from <FIG> that the pump unit <NUM>, the speed change mechanism <NUM>, the electric motor assembly <NUM>, and the power supply compartment <NUM> are successively arrayed in an extension direction of the axis L1 of the impeller.

A power supply mounting base <NUM> is arranged in the power supply compartment <NUM> to receive the power supply for supplying the electricity to the pump unit <NUM>, such as a battery pack capable of being repeatedly recharged. The battery pack can be guided into the power supply compartment <NUM> in a mounting direction. An axis L2 in the mounting direction is inclined at an angle relative to the axis L1 of the impeller. In the embodiment shown in <FIG>, this angle is less than <NUM>°, preferably between <NUM>° and <NUM>°, and more preferably between <NUM>° and <NUM>°. The power supply compartment <NUM> is obliquely arranged to make the most of an internal space of the housing <NUM>, enable the power supply mounting base <NUM> to be closer to the electric motor assembly <NUM>, and make it convenient for the user to install and remove the power supply. In other embodiments, in order to further reduce the size of the fluid transfer pump, the housing <NUM> is not provided with the power supply compartment <NUM>, and the power supply mounting base <NUM> may be arranged on an outer surface of the housing, such as a top surface or a side surface. In these embodiments, the battery pack is directly mounted on the outer surface of the housing <NUM>. In other embodiments, a separate power supply box may be provided and electrically connected to the pump unit <NUM>.

<FIG> shows the speed change mechanism <NUM>, a part of the pump unit <NUM> in drive connection with the speed change mechanism, and a part of the electric motor assembly <NUM> in drive connection with the speed change mechanism. In this embodiment, the speed change mechanism <NUM> comprises a gearbox shell <NUM> (shown in <FIG>) as well as a gear <NUM> and a ring gear <NUM> which are meshed with each other and accommodated in the gearbox shell. The gear <NUM> is in drive connection with an output shaft <NUM> of the electric motor assembly <NUM>, and the ring gear <NUM> is in drive connection with a drive shaft <NUM> of an impeller <NUM>.

<FIG> shows the ring gear <NUM>. The ring gear comprises a main ring gear body <NUM> on which inner teeth <NUM> are formed as well as a ring gear extension part <NUM> extending axially from the main ring gear body <NUM>. The ring gear extension part <NUM> and the drive shaft <NUM> of the impeller cooperate in such a way that they are unable to rotate relative to each other. For example, a shaft hole <NUM> formed in the ring gear extension part <NUM> can be in bonded connection, welded connection, clamped connection or threaded connection with the drive shaft <NUM>. Alternatively, a contour of an inner wall of the shaft hole <NUM> and a contour of the drive shaft <NUM> can be formed to match each other, such as planar contours.

<FIG> shows a first bearing <NUM>. The first bearing is disposed around the ring gear extension part <NUM>, and an outer side of the first bearing <NUM> abuts against a main pump body <NUM> (see <FIG>). <FIG> also shows a ring gear shaft <NUM>. The ring gear shaft defines a rotation axis of the ring gear <NUM>. <FIG> shows a bearing seat <NUM>. The bearing seat <NUM> is formed inside the ring gear <NUM> to accommodate a second bearing <NUM> (see <FIG>) disposed around the ring gear shaft <NUM>. The ring gear <NUM> further comprises a transition part <NUM> connecting the main ring gear body <NUM> to the ring gear extension part <NUM>, and at least one part of the bearing seat <NUM> is formed in the transition part <NUM>. The first bearing <NUM> and the second bearing <NUM> are respectively located outside and inside the ring gear <NUM>, and are spaced axially. During operation of the pump unit <NUM>, the first bearing <NUM> and the second bearing <NUM> respectively support the rotating ring gear <NUM> from the outside and the inside to avoid deviation of the rotation axis of ring gear <NUM>.

The speed change mechanism <NUM> in this embodiment is used to reduce the output rotation speed of the electric motor assembly <NUM>. Technical personnel can understand that speed reduction mechanisms in other forms are also applicable to the present invention, such as a planetary gear train, a worm gear, and a reduction gear train composed of a plurality of meshing spur gears and bevel gears, or their combination. A reduction ratio of the speed change mechanism is preferably <NUM>:<NUM> to <NUM>:<NUM>, and is more preferably <NUM>:<NUM> to <NUM>:<NUM>, such as <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, and <NUM>:<NUM>. In other embodiments, the speed change mechanism <NUM> may comprise a multistage reduction gear to raise the reduction ratio. The speed change mechanism <NUM> can reduce a rotation speed of the electric motor to be equal to a desired rotation speed of the impeller, so that the service life of the impeller is prolonged. Furthermore, the fluid transfer pump of the present invention can use a small DC high-speed electric motor due to the existence of the speed change mechanism <NUM>. This is conducive to reducing the size of the fluid transfer pump, decreasing energy consumption, and increasing battery life.

<FIG> shows the pump unit <NUM> according to an embodiment of the present invention. The pump unit comprises the main pump body <NUM> and the impeller <NUM>. The main pump body <NUM> defines a pump chamber <NUM>, and the impeller <NUM> is arranged in the pump chamber <NUM>. The impeller <NUM> comprises the drive shaft <NUM> in drive connection with the output end of the speed change mechanism <NUM>. In this embodiment, the drive shaft <NUM> is in drive connection with the ring gear extension part <NUM> of the ring gear <NUM>. A mounting flange <NUM> is formed at a rear end of the main pump body <NUM>, and the gearbox shell <NUM> (see <FIG>) can be fixed to the mounting flange <NUM>. An annular groove <NUM> is formed in an outer surface of a front end <NUM> of the main pump body <NUM>, and a sealing ring <NUM> is accommodated in the annular groove. The pump unit <NUM> further comprises a cover plate <NUM> and a mounting base <NUM> supporting the cover plate <NUM>. The cover plate <NUM> is used to close the pump chamber <NUM>, and the mounting base <NUM> is connected to the housing <NUM> of the fluid transfer pump. Optionally, a sealing plate <NUM> is additionally arranged between the cover plate <NUM> and the main pump body <NUM>. In addition, fastener holes <NUM>, <NUM>, <NUM> which are aligned axially can be formed in edges of the mounting base <NUM>, the cover plate <NUM>, and the main pump body <NUM>, facilitating assembly and disassembly of the pump unit <NUM>.

<FIG> shows the main pump body <NUM> and the impeller <NUM>. Close nipples <NUM>, <NUM> extend outward from the main pump body <NUM> in a direction transverse to the axis of the impeller, so as to form the fluid inlet <NUM> and fluid outlet <NUM> of the fluid transfer pump. The impeller <NUM> comprises a hub <NUM> and a plurality of flexible blades <NUM> radially extending outward from the hub <NUM> and spaced from one another in a circumferential direction. A hole <NUM> is formed in the center of the hub <NUM> to receive the drive shaft <NUM> such that the impeller <NUM> rotates together with the drive shaft <NUM>. Optionally, each flexible blade <NUM> has a roughly cylindrical outer end part <NUM>.

<FIG> shows a cross section of the pump unit <NUM>. A wall defining the pump chamber <NUM> comprises a cam-shaped wall portion <NUM> and a circular wall portion <NUM>. With reference to <FIG>, it can be seen that the cam-shaped wall portion <NUM> comprises a first arc part <NUM> defining a pump inlet <NUM>, a second arc part <NUM> defining a pump outlet <NUM>, and a third arc part <NUM> connected to the first arc part <NUM> and the second arc part <NUM>. In this embodiment, the radius of curvature of the first arc part <NUM>, the radius of curvature of the second arc part <NUM>, and the radius of curvature of the third arc part <NUM> are all smaller than the radius of curvature of the circular wall portion <NUM>. When the impeller <NUM> rotates in the pump chamber <NUM>, the outer end part <NUM> of the flexible blade <NUM> is in sliding contact with the cam-shaped wall portion <NUM> or the circular wall portion <NUM>. When in sliding contact with the cam-shaped wall portion <NUM>, the flexible blade <NUM> is obviously deformed due to extrusion of the first arc part <NUM>, the second arc part <NUM>, and the third arc part <NUM>.

In this embodiment, the impeller <NUM> has six flexible blades <NUM>. As shown in <FIG>, when the impeller <NUM> is put into the pump chamber <NUM>, an adjacent two of the flexible blades <NUM>, an outer wall of the hub <NUM>, and the wall defining the pump chamber <NUM> jointly define a fluid delivery cavity. In other words, the pump chamber <NUM> is divided into six fluid delivery cavities A-F by the impeller <NUM>. In <FIG>, the two flexible blades <NUM> in contact with the cam-shaped wall portion <NUM> (the first arc part <NUM>, the second arc part <NUM>, and the third arc part <NUM>) are significantly deformed, and the four flexible blades <NUM> in contact with the circular wall portion <NUM> are not deformed or merely slightly deformed. When the impeller <NUM> rotates clockwise, the deformed flexible blades <NUM> induce a size reduction and pressure rise of the fluid delivery cavities E, F, such that a fluid is forced to flow out via the pump outlet <NUM> formed in the second arc part <NUM>. At the same time, a negative pressure is generated in the fluid delivery cavity A, such that liquid is sucked into the pump chamber <NUM> via the pump inlet <NUM> formed in the first arc part <NUM>. It should be understood that a pumping path of the fluid is related to a rotation direction of the impeller <NUM>. If the impeller <NUM> is driven by the electric motor assembly <NUM> to rotate counterclockwise, the liquid enters the pump chamber <NUM> via the pump outlet <NUM> and is discharged via the pump inlet <NUM>.

<FIG> shows the electric motor assembly <NUM> according to an embodiment of the present invention. The electric motor assembly <NUM> comprises an electric motor <NUM>, a fan <NUM>, a front mounting frame <NUM>, a rear mounting frame <NUM>, and a control unit <NUM>. The electric motor <NUM> can be a battery-powered brushless DC electric motor or brushed DC electric motor. The fan <NUM> is arranged at a front end of the electric motor <NUM> and driven by the electric motor <NUM>. A gear <NUM> is mounted on an output shaft <NUM> of the electric motor <NUM> and meshed with teeth <NUM> formed on a wall of a center hole of the fan <NUM>. In other embodiments, the fan <NUM> may be fixed to the output shaft <NUM> to rotate together with the output shaft <NUM>. The fan <NUM> is used to generate a cooling air flow to accelerate heat dissipation of the electric motor <NUM>, and the fan <NUM> can be a centrifugal fan. The front mounting frame <NUM> and the rear mounting frame <NUM> are located at two ends of the electric motor <NUM>, and respectively hold a part of the electric motor <NUM> to fix the electric motor <NUM> at a predetermined position. The front mounting frame <NUM> comprises an end plate <NUM>, an annular electric motor cover part <NUM>, and a plurality of connecting bars <NUM> connecting the end plate <NUM> to the electric motor cover part <NUM>. A hole <NUM> is formed in the end plate <NUM> to allow the output shaft <NUM> to pass through. After assembly is completed, the fan <NUM> is located in the front mounting frame <NUM>. Due to obstruction of the end plate <NUM>, the air flow generated during rotation of the fan <NUM> can only flow radially outward out of the front mounting frame <NUM> via a side opening <NUM> between adjacent connecting bars <NUM>. Thus, the front mounting frame <NUM> can guide the cooling air flow to flow in a desired path.

In the embodiment shown in <FIG>, the control unit <NUM> is arranged at a rear end of the electric motor <NUM> to control rotation of the electric motor <NUM>. The control unit <NUM> comprises a circuit board, and an electronic component can be mounted on one side or two sides of the circuit board. The control unit <NUM> can start/stop the electric motor <NUM> on the basis of an input of the user, or change the rotation speed of the electric motor <NUM>. The control unit <NUM> can also determine, on the basis of operating parameters such as a current value and a voltage value of the electric motor <NUM>, whether or not the electric motor <NUM> operates normally, and stop the electric motor <NUM> when an abnormality is found. In other embodiments, a sensor used to detect pump parameters may be arranged in the fluid transfer pump, such as a pressure sensor, a temperature sensor, and a liquid sensor. The control unit <NUM> can control the electric motor <NUM> on the basis of the pump parameters detected by the sensor. When the pump parameters reach preset values, the control unit automatically controls the electric motor <NUM>.

In one embodiment, a protective shell <NUM> is provided for the control unit <NUM>. The control unit <NUM> is located at a rear end of the protective shell <NUM> or in the protective shell. The protective shell <NUM> can fulfil heat dissipation of the control unit <NUM>. As shown in <FIG>, the protective shell <NUM> is connected to the rear mounting frame <NUM>. Optionally, the control unit <NUM> is provided with a heat dissipation element or a heat conduction element to conduct heat to the protective shell <NUM> or ambient air. The heat dissipation element can be a metal radiator in contact with the circuit board and/or the electronic component, or a heat conductive adhesive used to fix the circuit board to the protective shell <NUM>. In some embodiments, the heat conductive adhesive basically fills an internal space of the protective shell <NUM>, and the control unit <NUM> is at least partially embedded into the heat conductive adhesive. Therefore, the control unit <NUM> is both fixed and radiated by means of the heat conductive adhesive.

For the sake of convenience for assembly, mounting features can be provided for all components of the electric motor assembly <NUM>. As shown in <FIG>, first fastener holes <NUM> are formed in the connecting bars <NUM> of the front mounting frame <NUM>; grooves <NUM> extending axially are formed in an outer surface of a stator core of the electric motor <NUM>; second fastener holes <NUM> are formed in the rear mounting frame <NUM>; and third fastener holes <NUM> are formed in the protective shell <NUM> of the control unit <NUM>. The first fastener hole <NUM>, the groove <NUM>, the second fastener hole <NUM>, and the third fastener hole <NUM> are aligned axially, such that a single fastener <NUM> (see <FIG>) can connect the front mounting frame <NUM>, the electric motor <NUM>, the rear mounting frame <NUM>, and the protective shell <NUM>.

Returning to <FIG>, it shows that the internal space of the housing <NUM> is divided into a plurality of areas <NUM>, <NUM>, <NUM> by at least one separator. The electric motor <NUM> and fan <NUM> of the electric motor assembly <NUM> are respectively located in different areas. Specifically, the fan <NUM> is located at a front side (a left side in the figure) of the electric motor <NUM>, and the fan <NUM> is located in the first area <NUM>; the electric motor <NUM> is located in the second area <NUM>; and the first area <NUM> and the second area <NUM> are separated by a first partition plate <NUM>. In other embodiments, the fan <NUM> may be arranged at a rear side of the electric motor <NUM>.

<FIG> shows a cross section of the fluid transfer pump. The first area <NUM> is at least partially defined by a first wall part <NUM> of the housing <NUM>, and a first opening <NUM> is formed in the first wall part <NUM> such that the first area <NUM> communicates with an external environment. As described above, the centrifugal fan <NUM> driven by the electric motor <NUM> enables the cooling air flow to radially outward flow out of the front mounting frame <NUM>. The air flow flowing out of the front mounting frame <NUM> enters the first area <NUM> of the housing <NUM>. Due to obstruction of the first partition plate <NUM>, the air flow cannot enter the second area <NUM> where the electric motor <NUM> is located. Therefore, the air flow in the first area <NUM> flows out of the housing <NUM> via the first opening <NUM>. Preferably, the first opening <NUM> is radially aligned to the fan <NUM> such that the air flow flows out of the housing <NUM> along the shortest path and takes away heat generated by the electric motor <NUM> during operation. The first opening <NUM> serves as an outlet for the cooling air flow.

The second area <NUM> is at least partially defined by a second wall part <NUM> of the housing <NUM>, and a second opening <NUM> is formed in the second wall part <NUM> such that the second area <NUM> communicates with the external environment. The electric motor <NUM> and the control unit <NUM> located at the rear end of the electric motor <NUM> are arranged in the second area. In this embodiment, the second opening <NUM> serves as an inlet for the cooling air flow to introduce air from the external environment. Due to the obstruction of the first partition plate <NUM>, the cooling air flow passes through the electric motor <NUM> under a suction effect of the fan <NUM>, so as to realize cooling. The cooling air flow heated by the heat generated by the electric motor <NUM> flows out of the housing <NUM> via the first opening <NUM>, and thus cannot flow back into the electric motor <NUM>. The second opening <NUM> can be formed above the electric motor <NUM> as shown in <FIG>, or be formed at other positions close to the electric motor <NUM>. In addition, the cooling air entering the second area <NUM> via the second opening <NUM> can also cool the control unit <NUM> adjacent to the electric motor <NUM>.

The third area <NUM> is at least partially defined by a third wall part <NUM> of the housing <NUM>. The third area <NUM> and the first area <NUM> are separated by a second partition plate <NUM>, and the pump unit <NUM> is located in the third area <NUM>. Due to obstruction of the second partition plate <NUM>, the heated cooling air flow cannot enter the third area <NUM>.

As shown in <FIG>, the first partition plate <NUM> extends from an inner wall of the housing <NUM> to an outer surface of the electric motor <NUM>, and the second partition plate <NUM> extends from the inner wall of the housing to an outer surface of the gearbox shell <NUM>. In order to improve sealing performance, a first sealing ring <NUM> can be arranged between the first partition plate <NUM> and the outer surface of the electric motor <NUM>, and a second sealing ring <NUM> can be arranged between the second partition plate <NUM> and the outer surface of the gearbox shell <NUM>.

<FIG> shows the pump unit <NUM>, the electric motor assembly <NUM>, and the speed change mechanism <NUM> which are in an assembled state. The first sealing ring <NUM> is disposed around the electric motor <NUM> and abuts against the front mounting frame <NUM>. The second sealing ring <NUM> is disposed around the gearbox shell <NUM>. Grooves are formed in the first sealing ring <NUM> and the second sealing ring <NUM> to achieve a close fit between the first sealing ring and the first partition plate <NUM> and between the second sealing ring and the second partition plate. The first partition plate <NUM> and the second partition plate <NUM> can be integrated with the housing <NUM> or mounted on the housing <NUM> as independent separators. In addition, <FIG> also shows a positioning component <NUM>. The positioning component is arranged between the pump unit <NUM> and the housing <NUM> of the fluid transfer pump to hold the pump unit <NUM> at a predetermined position in the housing <NUM>. The positioning component <NUM> can be made from rubber or other materials with damping characteristics to reduce the vibration of the housing <NUM> during operation of the pump unit <NUM> for noise reduction.

<FIG> shows the power supply compartment <NUM> according to one embodiment of the present invention. The power supply compartment <NUM> comprises a compartment shell <NUM> and a cover <NUM> covering the compartment shell <NUM>. The cover <NUM> is pivotally connected to the compartment shell <NUM> around a pin <NUM>. Optionally, a torsion spring is arranged on the pin <NUM> to bias the cover <NUM> to a closed position or a fully open position. In order to prevent the fluid from entering the power supply compartment <NUM> and making contact with the power supply and the power supply mounting base <NUM>, the power supply compartment <NUM> is preferably designed to be waterproof. In this embodiment, the cover <NUM> has a first sealing edge <NUM>, and the compartment shell <NUM> has a second sealing edge <NUM>. When the cover <NUM> is in the closed position, the first sealing edge <NUM> is aligned to the second sealing edge <NUM>.

<FIG> shows a cross section of a part of the power supply compartment <NUM>. To achieve sealing, a groove <NUM> is formed in the second sealing edge <NUM>; and the groove <NUM> is used to accommodate a sealing component (not shown in the figure), such as an elastic sealing ring. In other embodiments, the groove used to accommodate the sealing component may be formed in the first sealing edge <NUM> or formed by both the first sealing edge <NUM> and the second sealing edge <NUM>. At least one of the first sealing edge <NUM> and the second sealing edge <NUM> can have a ridge part <NUM>, <NUM> extending outward. When the cover <NUM> is in the closed position, the ridge part <NUM>, <NUM> abuts against the sealing component to hold the sealing component at a sealing position.

<FIG> also shows the power supply mounting base <NUM> and a locking component <NUM>. The power supply mounting base <NUM> is arranged on a side of the power supply compartment <NUM> that is close to the electric motor assembly <NUM>. The power supply mounting base <NUM> comprises a positioning part used to fix a battery and a contact part electrically connected to the battery. In this embodiment, the power supply mounting base <NUM> is formed as a part of an inner wall of the power supply compartment <NUM>, guide rails <NUM> used to guide the battery are formed on the compartment shell <NUM>, and the guide rails <NUM> are located on two sides of the power supply mounting base <NUM>.

The locking component <NUM> is used to lock the cover <NUM> in the closed position. The locking component <NUM> is able to move between a locked position and an unlocked position under operation performed by the user. When the locking component is in the locked position, at least one part of the locking component <NUM> presses against the first sealing edge <NUM> of the cover <NUM> to prevent the cover <NUM> from leaving the closed position. The compartment shell <NUM> comprises a protrusion part <NUM> extending from the second sealing edge <NUM>, and the locking component <NUM> is arranged on the protrusion part <NUM>. In the embodiments shown in <FIG> and <FIG>, the locking component <NUM> is formed as a locking knob <NUM> which has a locking part <NUM>. The first sealing edge <NUM> of the cover <NUM> is provided with a protrusive locking fitting part <NUM>, and a groove for accommodating the locking part <NUM> can be formed in the locking fitting part <NUM>. When the user turns the locking knob <NUM> toward the locked position, the locking knob <NUM> is obstructed by the locking fitting part <NUM>. The user needs to apply a certain force to move the locking knob <NUM> onto the locking fitting part <NUM> until the locking part <NUM> enters the groove in the locking fitting part <NUM>. When the user operates the locking knob <NUM>, force feedback perceived by the user can assist the user in confirming whether or not the locking knob <NUM> is in the correct locked position.

The locking knob <NUM> shown in <FIG> is in the locked position. The locking knob <NUM> comprises a rod <NUM> which extends downward, and the rod <NUM> penetrates through a through hole <NUM> formed in the protrusion part <NUM> of the cover <NUM>. The rod <NUM> is connected to a fastener <NUM>. The fastener <NUM> can be a screw engaged with a threaded hole formed in a tail end of the rod <NUM>. A baffle plate <NUM> is arranged between a head part of the fastener <NUM> and the tail end of the rod <NUM>. A biasing component <NUM> such as a spring is arranged between the baffle plate <NUM> and a bottom surface <NUM> of the protrusion part <NUM>. When the locking knob <NUM> is in the unlocked position, the biasing component <NUM> applies a biasing force to the baffle plate <NUM> to pull the locking component <NUM> downward, such that the locking knob <NUM> is held on the protrusion part <NUM>. When the user turns the locking knob <NUM> to the locked position, the locking knob <NUM> can be lifted by the locking fitting part <NUM> at the first sealing edge <NUM>, such that the baffle plate <NUM> moves upward. At this time, the distance between the baffle plate <NUM> and the bottom surface <NUM> of the protrusion part <NUM> becomes smaller, such that the biasing component <NUM> between them is compressed. The biasing component <NUM> under compression applies a higher biasing force to the baffle plate <NUM> to resist upward movement of the locking knob <NUM>; and in this way, the locking knob <NUM> is prevented from falling out of the protrusion part <NUM>.

<FIG> shows one of the half housings assembled to form the housing <NUM>. An upper part of the half housing is formed as the handle <NUM>, and a lower part of the half housing is formed as the base <NUM>. The base <NUM> has a front support part <NUM> and a rear support part <NUM>, and bottom surfaces of the front support part and the rear support part make contact with the ground or other supporting surfaces. The base <NUM> further comprises an elevation part <NUM> which is elevated relative to the bottom surfaces of the front support part <NUM> and the rear support part <NUM>. In an embodiment, the front support part <NUM> is roughly located below the pump unit <NUM>; the rear support part <NUM> is roughly located below the power supply compartment <NUM>; and the elevation part <NUM> is roughly located below the electric motor assembly <NUM>.

In some cases, the liquid may unexpectedly enter the housing <NUM>. For example, during operation on rainy days, rainwater may enter the housing <NUM> via the first opening <NUM> and the second opening <NUM> in the housing. To avoid accumulation of the liquid in the housing <NUM>, at least one of the support parts <NUM>, <NUM> and the elevation part <NUM> can be provided with a hole <NUM>, <NUM>, <NUM> that enables the internal space of the housing <NUM> to communicate with the external environment. When the pump unit <NUM> leaks, the hole <NUM> in the front support part <NUM> allows leaked liquid to flow out of the housing <NUM>. The elevation part <NUM> is a certain distance away from the ground, so as to reduce the possibility of water or debris on the ground entering the first area <NUM> and the second area <NUM>, thereby protecting the electric motor assembly <NUM>. In this embodiment, the elevation part <NUM> comprises a bottom wall <NUM> and a baffle plate <NUM> located on an inner side of the bottom wall <NUM>, the hole <NUM> is formed in the bottom wall, and a tortuous path from the hole <NUM> to the internal space of the housing is defined by the baffle plate <NUM>. During operation of the fluid transfer pump, cooling air can enter the second area <NUM> via the hole <NUM> or exit from the first area <NUM> via the hole <NUM>, and the baffle plate <NUM> can prevent the litter from entering the housing via the hole <NUM>.

Claim 1:
A fluid transfer pump, comprising:
a housing (<NUM>);
a pump unit (<NUM>), comprising an impeller (<NUM>);
an electric motor assembly (<NUM>) configured to drive the impeller (<NUM>) to rotate around an axis (L1) of the impeller (<NUM>); and
a power supply mounting base (<NUM>) configured to receive a power supply for supplying electricity to the pump unit (<NUM>),
characterised in that the fluid transfer pump further comprises:
a speed change mechanism (<NUM>) arranged between the pump unit (<NUM>) and the electric motor assembly (<NUM>),
wherein an internal space of the housing (<NUM>) is divided into a plurality of areas (<NUM>, <NUM>, <NUM>) by at least one separator,
the electric motor assembly comprises an electric motor (<NUM>), and a fan (<NUM>) driven by the electric motor and adjacent to one end of the electric motor, and
the fan (<NUM>) and the other end of the electric motor are respectively located in different areas.