String trimmer

The disclosure provides a string trimmer. The string trimmer includes a protective shield, a first motor, a blade and a fan. The first motor is arranged on one side of the protective shield, and a first rotation shaft of the first motor penetrates the protective shield to the other side of the protective shield. The blade is arranged on the other side of the protective shield, and the blade is connected with the first rotation shaft. The fan is arranged on the same side as the first motor, and the fan is mounted on the protective shield through a second rotation shaft. Wherein, a rotation speed ratio between the second rotation shaft and the first rotation shaft ranges from 0.5 to 4. With the string trimmer of the disclosure, the rotation speed of the blade and the fan are different.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on, and claims the priority from, Chinese application number CN202110270236.7, filed on Mar. 12, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The disclosure belongs to the technical field of the outdoor tools, particularly to a string trimmer.

BACKGROUND

Green vegetation is an indispensable environmental element for human beings, and the awareness of greening has become more and more popular among the people. Whether in golf courses, football fields, manors, villa courtyards, or ordinary residential areas, green turf is everywhere, which brings vigor and vitality to people's lives. However, the turf may become bumpy and disorganized without people's taking care of it. As a garden tool for turf care, string trimmers are being favored by more and more users, but at the same time, users have higher and higher requirements for the functions and experience of the string trimmers.

During an actual use of the string trimmer, a lot of broken grass, dust, etc. will fly to the road surface, which enables the road surface to be very dirty, and it is necessary to use a blower or other tools to re-treat the road surface. Such operations repeat work and waste labor. And in order to meet the above blowing requirements and effects, the fan needs to achieve a large output air volume and high work efficiency.

SUMMARY

The disclosure provides a string trimmer. With the string trimmer of the disclosure, a wide range of rotation speed ratios of the fan and the blade may be obtained.

The disclosure provides a string trimmer. The string trimmer includes a protective shield, a first motor, a blade and a fan. The first motor is arranged on one side of the protective shield, and a first rotation shaft of the first motor penetrates the protective shield to the other side of the protective shield. The blade is arranged on the other side of the protective shield, and the blade is connected with the first rotation shaft. The fan is arranged on the same side as the first motor, and the fan is mounted on the protective shield through a second rotation shaft. Wherein, a rotation speed ratio between the second rotation shaft and the first rotation shaft ranges from 0.5 to 4.

In an embodiment of the disclosure, the protective shield is semicircular, and a radius of a protective shield bottom surface of the protective shield is greater than a radius of the blade.

In an embodiment of the disclosure, the protective shield bottom surface is provided with a first through hole, the first through hole is located in a middle part of a straight side of the protective shield bottom surface, a blade fixing base is arranged in the first through hole, a second through hole is arranged on the blade fixing base, and the second through hole allows the first rotation shaft to pass through.

In an embodiment of the disclosure, the protective shield is provided with a first concave part located on one side of the fan, and the first concave part is arranged on a periphery of the first through hole.

In an embodiment of the disclosure, the string trimmer includes a first casing, the first casing is mounted on the first concave part, is hollow cylindrical shaped and allows the first motor to be placed in the first casing, and a handle is arranged on the first casing, and the handle is connected with one end of a connecting rod.

In an embodiment of the disclosure, the other end of the connecting rod is provided with a control device and a power supply device, the control device is connected with the first motor, and the power supply device is connected with the first motor and the control device.

In an embodiment of the disclosure, the protective shield is provided with a second concave part, the second concave part is located on a side away from the handle, the fan is fixed on the second concave part through the second rotation shaft, and the second rotation shaft is perpendicular to the protective shield bottom surface.

In an embodiment of the disclosure, the string trimmer includes a volute, the volute is fixed on the protective shield bottom surface, the fan is located between the volute and the protective shield, a side of the volute close to the protective shield is provided with a third concave part, a fan through hole is arranged on a bottom surface of the third concave part, and the fan through hole allows the second rotation shaft to pass through.

In an embodiment of the disclosure, the protective shield is provided with an air outlet, the air outlet is a through hole arranged on the protective shield bottom surface and is located on a side of the second concave part away from the first concave part.

In an embodiment of the disclosure, a tail part of the volute is provided with an air tube, the air tube includes a trimming air tube and a mowing air tube, the mowing air tube covers the air outlet, and the trimming air tube does not contact the air outlet.

In an embodiment of the disclosure, an air outlet opening is arranged on a side of the trimming air tube in contact with the protective shield bottom surface, the air outlet opening is located on a side of the trimming air tube away from the first concave part, and an air direction of the air outlet opening is perpendicular to the first rotation shaft.

In an embodiment of the disclosure, the volute includes a U-shaped concave part on a side away from the fan, the U-shaped concave part is provided with an opening, and the opening of the U-shaped concave part is connected with an opening of the first concave part.

In an embodiment of the disclosure, the string trimmer includes an upper cover, the upper cover is connected above the U-shaped concave part, and the upper cover is provided with a plurality of air inlets.

In an embodiment of the disclosure, the string trimmer further includes a driving wheel and a driven wheel, the driving wheel and the driven wheel are arranged on the same side as the fan, the driving wheel is connected with the first rotation shaft and is located in the first concave part, the driven wheel is connected with the second rotation shaft and is located in the U-shaped concave part, and the driving wheel and the driven wheel are connected through a belt.

In an embodiment of the disclosure, the protective shield includes a plurality of air outlets, and the plurality of air outlets surround the second concave part.

In an embodiment of the disclosure, the string trimmer further includes a second motor, the second motor is arranged on the same side as the first motor, and the second motor is connected with the second rotation shaft.

In an embodiment of the disclosure, the string trimmer includes a second casing, the second casing is located on the protective shield, the second motor is arranged in the second casing, and a plurality of air inlets are arranged on a top of the second casing.

In an embodiment of the disclosure, the fan is a centrifugal fan, the fan and the second motor are connected in sequence above the second concave part through the second rotation shaft, and the fan is located between the protective shield and the second motor.

In an embodiment of the disclosure, the fan is an axial flow fan, the fan and the second motor are connected in sequence above the second concave part through the second rotation shaft, and the fan is located on a side of the second motor away from the protective shield.

In an embodiment of the disclosure, the fan includes a first fan and a second fan, the first fan, the second motor and the second fan are connected in sequence above the second concave part through the second rotation shaft, the first fan is located between the protective shield and the second motor, and the second fan is located on a side of the second motor away from the protective shield.

With the string trimmer of the disclosure as described above, a rotation speed of the fan may be different from a rotation speed of the blade through arranging the fan and the blade on different rotation shafts. A diameter of a fan blade of the fan is not affected by a structure of the first motor through arranging the fan and the blade on different sides of the protective shield.

Of course, it is not necessary for any product implementing the disclosure to achieve all of the above-described advantages simultaneously.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the disclosure will be clearly and completely described below with reference to the accompanying figures in the embodiments of the disclosure. Obviously, the described embodiments are only some, but not all embodiments of the disclosure. Based on the embodiments of the disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection range of the disclosure.

Please refer toFIG. 1throughFIG. 4. The disclosure provides a sting trimmer1. The sting trimmer1may realize a mowing function and a grass trimming function. When using the mowing function, an axis of a motor is perpendicular to a bottom surface, which means that a blade500is parallel to the ground. When using the grass trimming function, an axis of a motor is parallel to the ground, which means that a blade500is perpendicular to the ground. In the disclosure, the sting trimmer1has a blowing function when mowing or grass trimming. In the disclosure, a fan640and the blade500have different rotation speeds through arranging the fan640and the blade500on different rotation shafts, so that a suitable blowing air force may be obtained during mowing or grass trimming.

Please refer toFIG. 1throughFIG. 4. The disclosure provides various embodiments of fans460and blades500with different rotation speeds. In an embodiment of the disclosure, a driving wheel560is arranged on a first rotation shaft531, a driven wheel630is arranged on a second rotation shaft631, and the driving wheel560and the driven wheel630are connected through a belt561or a chain transmission. Through setting a ratio of a radius of the driving wheel560to a radius of the driven wheel630, the first rotation shaft531and the second rotation shaft631may obtain suitable rotation speeds. In other embodiments of the disclosure, the rotation speed of the first rotation shaft531is controlled by a first motor530, and the rotation speed of the second rotation shaft631is controlled by a second motor632, so that the first rotation shaft531and the second rotation shaft631are independently controlled, and the first rotation shaft531and the second rotation shaft631may obtain suitable rotation speeds. For details, please refer to the embodiments and the drawings.

Please refer toFIG. 1andFIG. 2. The disclosure provides the string trimmer1. The string trimmer1includes a power supply assembly10, a control assembly20, a connecting rod31, a protective shield40, a cutting assembly50and a blowing assembly60. The power supply assembly10includes at least one battery pack, which is used to supply power for each electrical device of the string trimmer1. A control panel is arranged in the control assembly20, which is used to realize switch, speed adjustment and other functions of the string trimmer1. The connecting rod31is used to connect an operation end and a working end of the string trimmer1, the connecting rod31is a hollow structure, and an auxiliary handle32is further arranged on the connecting rod31. The operation end includes the power supply assembly10and the control assembly20, and the working end includes the protective shield40, the cutting assembly50and the blowing assembly60. The cutting assembly50and the blowing assembly60are mounted on the protective shield40, the cutting assembly50is used for mowing, and the blowing assembly60is used for blowing the cut grass.

Please refer toFIG. 1andFIG. 3. In an embodiment of the disclosure, a casing30is arranged at the operation end of the string trimmer1for arranging the power supply assembly10and the control assembly20. The power supply assembly10includes at least one battery pack, and the battery pack is detachable. The power supply assembly10is electrically connected with power devices of the control assembly20, the cutting assembly50and the blowing assembly60. The battery pack is electrically connected with the control panel and the first motor530. The control assembly20is arranged in the casing30, between the power supply assembly10and the working end of the string trimmer1, and close to the power supply assembly10. The control assembly20includes the control panel, the control panel is electrically connected with the first motor530and the second motor632, and is used to control an on-and-off and rotation speeds of the first motor530and the second motor632.

Please refer toFIG. 2andFIG. 3. In an embodiment of the disclosure, the protective shield40, the cutting assembly50and a blowing assembly60are arranged at the working end of the string trimmer1. The cutting assembly50and the blowing assembly60are mounted on the protective shield40, and working parts of the cutting assembly50and the blowing assembly60are located on different sides of the protective shield40respectively, which means that the blade500and the fan640are located on different sides of the protective shield40respectively. In this embodiment, the cutting assembly50is connected with the connecting rod31.

Please refer toFIG. 3throughFIG. 12. In an embodiment of the disclosure, through arranging the driving wheel560on the first rotation shaft531and arranging the driven wheel630on the second rotation shaft631, the driving wheel560is connected with the driven wheel630by means of the belt561or the chain transmission. Through setting the ratio of the radius of the driving wheel560to the radius of the driven wheel630, the first rotation shaft531and the second rotation shaft631may obtain suitable rotation speeds. In this embodiment, the cutting assembly50mainly includes the first motor530and the blade500. The blowing assembly60mainly includes the fan640and the transmission mechanism. The transmission mechanism includes the driving wheel560, the belt561and the driven wheel630.

Please refer toFIG. 4andFIG. 8. In an embodiment of the disclosure, the protective shield40is semicircular. The protective shield40includes a protective shield bottom surface400and a protective shield side surface410. The protective shield bottom surface400is a main body of the protective shield40and is semicircular. The protective shield side surface410is arranged on an arc side of the protective shield bottom surface400, and the protective shield side surface410is perpendicular to the protective shield bottom surface400. The blade500is mounted on the protective shield bottom surface400and located on a side of the protective shield side surface410, and the blade500is parallel to the protective shield bottom surface400. A radius of the protective shield bottom surface400is greater than a radius of the blade500. The fan640is mounted on the protective shield bottom surface400and on a side opposite to the protective shield side surface410. When using the string trimmer1for mowing, the protective shield bottom surface400is parallel to the ground, and the blade500is parallel to the ground. When using the string trimmer1for trimming, the protective shield bottom surface400is perpendicular to the ground, the blade500is perpendicular to the ground, and a straight side of the protective shield bottom surface400is close to the ground.

Please refer toFIG. 4,FIG. 8andFIG. 12, a first through hole401is arranged on the protective shield bottom surface400and close to a middle part of the straight side of the protective shield bottom surface400, and the first through hole401is circular. A blade fixing base570is placed in the first through hole401, and a radius of an outer circumference of the blade fixing base570is substantially equal to a radius of the first through hole401.

Further, please refer toFIG. 12. The blade fixing base570is provided with a second through hole572in a shape of a circle. The blade fixing base570passes through the first through hole401to the other side of the protective shield bottom surface400for fixing the blade500. And the first rotation shaft531of the first motor530is allowed to pass through the second through hole572of the blade fixing base570to the other side of the protective shield bottom surface400. When the first motor530works, the first rotation shaft531rotates and drives the blade500connected with the first rotation shaft531to rotate. The blade fixing base570is provided with at least one U-shaped groove571, the U-shaped groove571is located on a side close to the first motor530(a side away from the blade500) for engaging with the driving wheel560. In this embodiment, the number of U-shaped grooves571is, for example, two.

Further, please refer toFIG. 7andFIG. 8. A side wall which is higher than the protective shield bottom surface400is arranged on the side of the protective shield bottom surface400away from the protective shield side surface410and at a periphery of the first through hole401, which defines a first concave part403with the protective shield bottom surface400. The first concave part403is used to place the driving wheel560. An opening is further arranged on one side of the first concave part403, and the opening of the first concave part403faces the fan640for placing the belt561. The belt561connects the driving wheel560with the driven wheel630.

Please refer toFIG. 4,FIG. 7andFIG. 8. In the first concave part403, the driving wheel560is placed on a side of the U-shaped groove571of the blade fixing base570. A center of the driving wheel560is provided with a central through hole, and the central through hole is fixedly connected with an output end of the first motor530, which means fixedly connected with the first rotation shaft531. When the first motor530works, the first rotation shaft531rotates, and drives the driving wheel560and the blade500connected with the first rotation shaft531to rotate.

Please refer toFIG. 3,FIG. 4andFIG. 9. Above the first concave part403, a motor fixing plate540is fixedly connected on a side of the driving wheel560away from the blade fixing base570. The motor fixing plate540is mounted above the first concave part403for fixing a first casing510and the first motor530on the protective shield40. One side of the motor fixing plate540is fixed on a side wall of the first concave part403, so that the motor fixing plate540is fixed on the protective shield40, and the other side of the motor fixing plate540is fixedly connected with the first casing510. An interior of the first casing510is provided with the first motor530.

Please refer toFIG. 9. A third through hole541is arranged in a middle of the motor fixing plate540, and the third through hole541allows the first rotation shaft531to pass through. On the motor fixing plate540, a plurality of shock-absorption pad holes542are arranged at a periphery of the third through hole541for fixing the shock-absorption pad532. The number of the shock-absorption pad holes542is, for example, three, and the plurality of shock-absorption pad holes542are evenly distributed on a circumference with the third through hole541as a center of the circle. On the motor fixing plate540, a plurality of casing fixing holes543are arranged for fixing the first casing510at a periphery of the shock-absorption pad hole542. The number of the casing fixing holes543is, for example, 2. On the motor fixing plate540, a plurality of motor fixing holes544are further arranged at a periphery of the casing fixing hole543for fixing the motor fixing plate540on the protective shield40. The number of the motor fixing holes544is, for example, 3. The motor fixing plate540is further provided with a connecting rod fixing hole545for fixing the connecting rod31.

Please refer toFIG. 4throughFIG. 9. In an embodiment of the disclosure, the first casing510is in a through hollow cylindrical shape which includes a cylindrical side surface. One side of the first casing510is connected with the motor fixing plate540, and the other side of the first casing510is provided with a motor cover520. The first motor530is located in the first casing510. In the cylindrical space defined by the first casing510, the motor cover520and the motor fixing plate540, the output end of the first motor530, namely the first rotation shaft531, passes through the third through holes541on the motor fixing plate540, a central through hole of the driving wheel560and the second through hole572of the blade fixing base570in the protective shield40to be fixedly connected with the blade500.

Further, please refer toFIG. 6. In an embodiment of the disclosure, a handle511is arranged on the first casing510, and the handle511is fixedly connected with the connecting rod31. The handle511is in a cylindrical hollow structure. The cylindrical hollow structure in the handle511communicates with a cylindrical space of the first casing510and penetrates the hollow connecting rod31, which realizes an electrical connection of the control assembly20and the power supply assembly10with the first motor530.

Please refer toFIG. 3andFIG. 4. In an embodiment of the disclosure, a shock-absorption pad532is further arranged between the first motor530and the motor fixing plate540. The shock-absorption pad532is arranged between the first motor530and the motor fixing plate540to prevent a vibration generated by the first motor530from affecting an operation of the driving wheel560on the other side of the motor fixing plate540when the first motor530is working, which affects the blade500and the fan640to work.

Please refer toFIG. 4andFIG. 8. On a side of the protective shield bottom surface400away from the protective shield side surface410, a second concave part404is further arranged on a side close to the opening of the first concave part403. The second concave part404is a circular concave part lower than the protective shield bottom surface400, used for placing a bearing of the second rotation shaft631and fixing the second rotation shaft631on the bearing.

Please refer toFIG. 3,FIG. 4andFIG. 7. Above the second concave part404, the fan640, the driven wheel630and another bearing of the second rotation shaft631is fixedly connected in sequence through the second rotation shaft631. A volute610is mounted on the protective shield40and is located above the fan640. An upper cover620is further mounted on the volute610for arranging an air inlet621.

Please refer toFIG. 3,FIG. 4andFIG. 7. On the second concave part404, the second rotation shaft631perpendicular to the protective shield bottom surface400is fixed through a bearing. The fan640is located above the second concave part630and is fixedly connected with the second rotation shaft631, which allows the second rotation shaft631to drive the fan640to rotate. The fan640is a centrifugal fan.

Please refer toFIG. 4,FIG. 10andFIG. 11. In an embodiment of the disclosure, the volute610is mounted above the fan640. The volute610is fixed on the protective shield bottom surface400by a nut. A third concave part613is arranged on a side of the volute610close to the protective shield bottom surface400, and the fan640is located in the third concave part613. The third concave part613is in a shape of a “9”, and a side wall of the third concave part613is in contact with the protective shield40. A bottom surface of the third concave part613is provided with a fan through hole611, and the fan through hole611allows the second rotation shaft631to pass through the fan through hole611to connect the fan640and the driven wheel630. A radius of the fan through hole611is much greater than a radius of the second rotation shaft631, and air entering from the air inlet621passes through the fan through hole611to the fan640. A U-shaped concave part612is arranged on the other side of the volute610. The U-shaped concave part612is used for placing the driven wheel630and belt561. An opening of the U-shaped concave part612faces the driving wheel560and corresponds to the opening of the first concave part403.

Further, please refer toFIG. 3,FIG. 4andFIG. 7. The driven wheel630is located on a side of the fan640away from the second concave part630, and is arranged on the U-shaped concave part612of the volute610. The second rotation shaft631passes through a center of the driven wheel630and allows the second rotation shaft631to drive the driven wheel630to rotate. And heights of the driven wheel630and the driving wheel560on the protective shield bottom surface400are the same. In this embodiment, the driving wheel560and the driven wheel630are connected through the belt561. In other embodiments, a chain transmission may also be set between the driving wheel560and the driven wheel630.

Please refer toFIG. 3throughFIG. 6. The upper cover620is arranged on the volute610, and the upper cover620is fixedly connected above the U-shaped concave part612. The upper cover620is provided with a plurality of air inlets621, and the volute610defines an air passage of the fan640.

Please refer toFIG. 5andFIG. 8. An air outlet405is further arranged on the protective shield bottom surface400and in an area covered by the volute610. The air outlet405may be in any shape. In this embodiment, the air outlet405is, for example, a rectangle. The air enters through the air inlet621on the upper cover620, passes through the air passage of the volute610, and then passes through the air outlet405on the protective shield40to the other side of the protective shield40, which means a side where the blade500is located.

Please refer toFIG. 1andFIG. 4. In an embodiment of the disclosure, the blade500is located on the other side of protective shield40relative to the fan640. The blade500is fixed on the first rotation shaft531through the blade fixing base570in the first through hole401. The blade500is in a rectangular shape. The first rotation shaft531passes through a center of the blade500. When the blade500rotates, both ends of the blade500are inside an arc side of the protective shield bottom surface400, but extend out of the straight side of the protective shield bottom surface400. On a side of the blade500away from the blade fixing base570, a blade plate501and a nut are sequentially fixed on the first rotation shaft531for fixing the blade500.

Please refer toFIG. 1andFIG. 8. In an embodiment of the disclosure, on the protective shield40, a traveling wheel connecting device402is further arranged on a side close to the connecting rod31for fixing a traveling wheel33and pushing the string trimmer1to move.

Please refer toFIG. 3andFIG. 12. When the power supply assembly10supplies power for the first motor530and the control assembly20sends out a control signal, the first motor530works to drive the output end of the first motor530, which means that the first rotation shaft531is driven to rotate, thereby driving the driving wheel560and the blade500fixedly connected with the first rotation shaft531to rotate, and then the string trimmer1realizes a mowing function. At the same time, the driving wheel560drives the driven wheel630connected with the driving wheel560through the belt561to rotate, thereby driving the fan640fixedly connected with the driven wheel630to rotate, so as to realize a blowing function of the string trimmer1. In this embodiment, a radius of the driving wheel560is different from a radius of the driven wheel630, so that the rotation speeds of the first rotation shaft531and the second rotation shaft631are different, and thus the rotation speeds of the fan640and the blade500are different. A rotation speed ratio between the first rotation shaft531and the second rotation shaft631is, for example, from 0.5 to 4.

Please refer toFIG. 13throughFIG. 26. In other embodiments of the disclosure, the rotation speed of the first rotation shaft531is controlled by the first motor530, and the rotation speed of the second rotation shaft631is controlled by the second motor632, so that the first rotation shaft531and the second rotation shaft631are independently controlled, and both of the first rotation shaft531and the second rotation shaft631may obtain suitable rotation speeds. In these embodiments, the driving wheel560, the driven wheel630and the belt561do not need to be arranged, but the second motor632needs to be arranged to drive the second rotation shaft631to rotate. In this embodiment, the cutting assembly50mainly includes the first motor530and the blade500, and the blowing assembly mainly includes the second motor632and the fan640.

Please refer toFIG. 12throughFIG. 23. In an embodiment of the disclosure, the protective shield40is semicircular. The whole of the protective shield40is the same as the previous embodiments. The protective shield40includes the protective shield bottom surface400and the protective shield side surface410. The protective shield bottom surface400is a main body of the protective shield40and is semicircular. The protective shield side surface410is arranged on an arc side of the protective shield bottom surface400, and the protective shield side surface410is perpendicular to the protective shield bottom surface400. And the first through hole401is arranged close to the middle part of the straight side of the protective shield bottom surface400, and the first through hole401is circular. The blade fixing base570is placed in the first through hole401. The blade fixing base570is provided with the second through hole572, and the first rotation shaft531is allowed to pass through the second through hole572to the other side of the protective shield bottom surface400. When the first motor530works, the first rotation shaft531rotates, and the blade500connected with the first rotation shaft531rotates. The blade fixing base570is further provided with at least one U-shaped groove571which is located on the side close to the first motor530. In this embodiment, the number of U-shaped grooves571is, for example, two.

Further, please refer toFIG. 13andFIG. 16. The first concave part403is arranged on the side of the protective shield bottom surface400away from the protective shield side surface410and at the periphery of the first through hole401. The first motor530is placed on the first concave part403. The first rotation shaft531, the output end of the first motor530, passes through the first through hole401at a center of the first concave part403to the other side of the protective shield40and is connected with the blade500on the other side of the protective shield40. When the first motor530works, the first rotation shaft531rotates and drives the blade500connected with the first rotation shaft531to rotate.

Further, please refer toFIG. 13andFIG. 16. In the first concave part403, a plurality of shock-absorption pad holes542are arranged at the periphery of the first through hole401for fixing the shock-absorption pad532. The number of the shock-absorption pad holes542is, for example, three, and the plurality of shock-absorption pad holes542are evenly distributed on a circumference with the first through hole401as a center of the circle. In the first concave part403, a plurality of casing fixing holes543are arranged for fixing the first casing510at the periphery of the shock-absorption pad hole542. The number of the casing fixing holes543is, for example, 3.

Please refer toFIG. 13throughFIG. 16. In an embodiment of the disclosure, a shock-absorption pad532, a first motor530and a first casing510are sequentially mounted above the first concave part403, and the shock-absorption pad532and the first motor530are arranged in the first casing510.

Further, please refer toFIG. 13throughFIG. 16. In an embodiment of the disclosure, the first casing510is in a through hollow cylindrical shape which includes a cylindrical side surface. One side of the first casing510is fixed on the casing fixing hole543in the first concave part403by bolts, and the other side of the first casing510is provided with the motor cover520. The first motor530is located in a cylindrical space defined by the first casing510, the motor cover520and the first concave part403. The output end of the first motor530, namely the first rotation shaft531, passes through the second through hole572of the blade fixing base570in the protective shield40and is fixedly connected with the blade500.

Further, please refer toFIG. 14. In an embodiment of the disclosure, the handle511is arranged on the first casing510, and the handle511is fixedly connected with the connecting rod31. The handle511is in a cylindrical hollow structure. The cylindrical hollow structure in the handle511communicates with a cylindrical space of the first casing510and penetrates the hollow connecting rod31, which realizes an electrical connection of the control assembly20and the power supply assembly10with the first motor530.

Please refer toFIG. 13. In an embodiment of the disclosure, the shock-absorption pad532is further arranged between the first motor530and the first concave part403. The shock-absorption pad532is arranged between the first motor530and the first concave part403to prevent a vibration generated by the first motor530from affecting an operation of the blade500on the other side of the protective shield40when the first motor530is working.

Please refer toFIG. 13,FIG. 15andFIG. 16. A second concave part404is arranged on the protective shield40, on a side of the fan640and a side away from the handle511. The second concave part404is a circular concave part lower than the protective shield bottom surface400for placing the bearing of the second rotation shaft631and fixing the second rotation shaft631on the bearing, and the second rotation shaft631is perpendicular to the protective shield bottom surface400.

Please refer toFIG. 13throughFIG. 26. In an embodiment of the disclosure, the fan640and the second motor632are fixedly connected above the second concave portion404through the second rotation shaft631.

Please refer toFIG. 13throughFIG. 18. In an embodiment of the disclosure, the fan640is the centrifugal fan. The fan640and the second motor632are sequentially fixedly connected above the second concave part404through the second rotation shaft631. The fan640is mounted between the second motor632and the protective shield40, and the fan640is close to the air outlet405. The volute610is arranged above the fan640, and the second casing622is mounted on the volute610and covers the second motor632. A plurality of air inlets621are further arranged on a plane of the second casing622parallel to the fan640, and the volute610defines the air passage of the fan640. The air outlet405is arranged on the protective shield bottom surface400and in the area covered by the volute610. The air enters from the air inlet621on the upper cover620, passes through the air passage of the volute610, and then passes through the air outlet405on the protective shield40to the other side of the protective shield bottom surface400, which means the side where the blade500is located.

Please refer toFIG. 14,FIG. 17andFIG. 18. In an embodiment of the disclosure, the volute610is fixed on the protective shield40by a nut. The third concave part613is arranged on a side of the volute610close to the protective shield40. The third concave part613is in a shape of a “9”, and a side wall of the third concave part613is in contact with the protective shield40. The bottom surface of the third concave part613is provided with the fan through hole611. The fan is located in the third concave part613. The second rotation shaft631is fixedly connected with the fan640through the fan through hole611.

Further, please refer toFIG. 17. On a side of the volute610away from the protective shield40, with a center of the fan through hole611as the center, two side walls with different radii are surrounded to define a limiting structure614for limiting a position of the second motor632. And a plurality of through holes penetrating through a surface of the third concave part613of the volute610are further arranged between the two side walls with different radii, and the air inlet621is used for air intake.

Further, please refer toFIG. 17andFIG. 18. An air tube615is arranged at a tail end of the volute610. The tube duct615is part of the volute610. When the volute610is mounted on the protective shield40, the air tube615is located above the air outlet405, and the air tube615is a detachable structure.

Please refer toFIG. 26. In another embodiment of the disclosure, the air tube615includes a trimming air tube615aand a mowing air tube615b.When the air tube615mounted in the volute610is a mowing air tube615b,the mowing air tube615bcovers the air outlet405on the protective shield40, and the air generated by the fan640is discharged from the air outlet405. A direction of the air outlet is parallel to an axis of the motor shaft. When the air tube615mounted on the volute is a trimming air tube615a,the trimming air tube615adoes not contact the air outlet405on the protective shield40. And an air outlet opening615cis arranged on a side of the trimming air tube615athat is perpendicular to the protective shield bottom surface400. The air outlet opening615cis located away from a side away from the first motor530. The air generated by the fan640is discharged through the air outlet opening615c.The direction of the air outlet is perpendicular to the axis of the motor shaft and parallel to the straight side of the protective shield bottom surface400.

Please refer toFIG. 20throughFIG. 23. In another embodiment of the disclosure, the fan640is, for example, an axial flow fan. The second motor632and the fan640are sequentially fixedly connected above the second concave part404through the second rotation shaft631. The second motor632is directly mounted on the protective shield40and above the second concave part404. The fan640is mounted on a side of the second motor632away from the protective shield40. And close to the air outlet405, the second casing622is mounted on the protective shield40and above the second concave part404. And the second casing622covers the second motor632. In this embodiment, the plurality of air inlets631on the second casing622are arc-shaped and distributed around a concentric circle. Further, in this embodiment, the second concave part404is a circular structure with a plurality of protruding parts, and a radius of the circular structure is substantially equal to the radius of the second motor632. The protective shield40is further provided with a plurality of air outlets405, the plurality of the air outlets405are arranged around the second concave part404, and the plurality of air outlets405are covered by the second casing622. When an axial flow motor rotates, the air enters from the air inlet621at a top of the second casing622, passes through a gap between the second casing622and the second motor632, and then is discharged through the plurality of the air outlets405on the protective shield40. In this embodiment, the volute610does not need to be arranged.

Please refer toFIG. 24throughFIG. 26. In another embodiment of the disclosure, in order to increase an air power, a plurality of fans640are arranged, and the fans640include a first fan640aand a second fan640b.The first fan640ais a centrifugal fan, located between the second motor632and the protective shield40and close to the air outlet405. The second fan640bis an axial flow fan, located on the side of the second motor632away from the protective shield40and close to the air inlet621. The centrifugal fan and the axial flow fan are used at the same time to increase the air power of the fan640.

Please refer toFIG. 13throughFIG. 26. A position and fixing way of the blade500of the string trimmer1of the disclosure is the same as in the previous embodiments, which is located on the other side of the protective shield40relative to the fan640and fixed on the first rotation shaft531through the blade fixing base570. On the side of the blade500away from the blade fixing base570, a blade plate501and a nut are sequentially fixed on the first rotation shaft531for fixing the blade500.

Please refer toFIG. 13andFIG. 26. In an embodiment of the disclosure, on the protective shield40, the traveling wheel connecting device402is arranged on the side close to the connecting rod31for fixing a traveling wheel33to push the string trimmer1to move.

Please refer toFIG. 13andFIG. 26. When the power supply assembly10supplies power for the first motor530and the second motor632, and the control assembly20sends out a control signal, the first motor530and the second motor632work, the first motor530drives the output end of the first motor530, which means that the first rotation shaft531is driven to rotate, thereby driving the blade500fixedly connected with the first rotation shaft531to rotate, and then the string trimmer1realizes a mowing function. At the same time, the second motor632drives the second rotation shaft631at the output end of the second motor632to rotate, thereby driving the fan640fixedly connected with the second motor632to rotate, so as to realize the blowing function of the string trimmer1. In this embodiment, powers of the first motor530and the second motor632are different, rotation speeds of the first rotation shaft531and the second rotation shaft631are different, and thus the rotation speeds of the fan640and the blade500are different. A rotation speed ratio between the first rotation shaft531and the second rotation shaft631is, for example, from 0.5 to 4.

The disclosure provides a string trimmer. Firstly, in one of the embodiments, in a case of a small transmission ratio, a center distance between a motor shaft (the first rotation shaft531) and a fan blade shaft (the second rotation shaft631) may be increased, so that a diameter of fan blades of the fan640may be increased, and then the air force increases, which prevents a diameter of the fan blade from being affected by a motor structure. In other embodiments, the fan640and the blade500are controlled independently. The center distance between the motor shaft (the first rotation shaft531) and the fan blade shaft (the second rotation shaft631) may be increased, so that the diameter of the fan blades of the fan640may be increased, and then the air force increases, which prevents the diameter of the fan blade from being affected by the motor structure.

Secondly, the fan blade shaft (the second rotation shaft631) is not coaxial with the motor shaft (the first rotation shaft531), a structure of the fan blade is not affected by the motor, and a centrifugal blade or an axial flow blade may be used.

Furthermore, in one embodiment, a belt transmission may keep the fan blades of the fan640away from the motor shaft (the first rotation shaft531), so that the blade500on the motor shaft (the first rotation shaft531) may obtain a greater cutting depth. In other embodiments, the fan640and the blade500are controlled independently. The belt transmission may keep the fan blades of the fan640away from the motor shaft (the first rotation shaft531), so that the blade500on the motor shaft (the first rotation shaft531) may obtain a greater cutting depth.

Finally, a gap between the driving wheel560and the driven wheel630is not affected by a structure of the first motor530. A wide range of rotation speed ratios, from 0.5 to 4, may be obtained through a one-stage transmission or a separate control of different motors, and the diameter of the fan blades of the fan640is not affected under any rotation speed ratio.

In the description of this specification, a description with reference to the terms “this embodiment”, “embodiment ”, “specific embodiment ”, etc. means that a specific feature, structure, material or characteristic described in connection with this embodiment or example is included in at least one embodiment or example of the disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The embodiments of the disclosure described above are only used to help illustrate the disclosure. The embodiments do not exhaustively describe all the details, nor do they limit the disclosure to the specific embodiments described. Obviously, many modifications and variations are possible according to this specification. The embodiments are specifically described in the specification in order to better explain the principles and practical applications of the disclosure, so that those skilled in the art can well understand and utilize the disclosure. The disclosure is limited only by the claims and their full scope and equivalents.