Edge trimmer

Abstract

The invention relates to an edge trimmer which comprises a machine shell, a motor and a cooling fan. The cooling fan is provided with a fan hub installed on the motor, first blades protruding from the periphery of the fan hub and second blades protruding from the first blades, the edge trimmer is provided with an air inlet formed in the upper portion of the machine shell and an air outlet close to the lower portion of the cooling fan, and cooling air flows into the motor from the air inlet and flows through the cooling fan to generate an air channel. The air duct comprises a first air duct formed by rotation of the first blade and a second air duct formed by rotation of the second blade, and cooling air of the first air duct and the second air duct is discharged from the air outlet after being converged; the number K1 of the first blades and the number K2 of the second blades meet the following relation: K1 = K2 / n, and n is a natural number. The second blades protruding from the first blades of the cooling fan, the first air channel formed by rotation of the first blades and the second air channel formed by rotation of the second blades are converged and then flow out of the air outlet, cooling of the whole machine is achieved, and the operation experience of a user is improved.

Description

[Technical field]

[0001] The invention relates to the technical field of electric tools, in particular to an edge trimmer. [Background Technology]

[0002] Trimmers are often used to trim and cut wood. Regardless of whether they are DC or AC machines, the machine structure is simpler than other handheld power tools. Due to its simple internal structure, the airflow resistance of the motor cooling air path is small. In order to meet the heat dissipation requirements of high-power motors, axial flow fans are often used to dissipate heat for DC / AC motors.

[0003] When the trimmer is in operation, the operator holds the gripping part of the machine to operate. Since the machine occupies a certain height, in order to improve the user experience during operation and ensure that the machine conforms to the ergonomic design, the model and specification of the lower fixed bearing of the fixed motor are often larger than the upper bearing, so that the center of gravity of the machine is close to the gripping part, and the operation is more comfortable. However, the trimmer body often adopts a "straight tube" structure, and it is necessary to consider how to ensure that the motor is well cooled, otherwise the heat generated by the motor will be transmitted to the gripping part through the "straight tube" body, which will bring a bad operating experience and reduce the reliability and life of the machine.

[0004] In view of this, it is indeed necessary to provide an improved trimming machine to overcome the defects of the prior art. [Summary of the invention]

[0005] In view of the deficiencies in the prior art, an object of the present invention is to provide a trimmer with good heat dissipation effect and good user operating experience.

[0006] The present invention solves the problems of the prior art by adopting the following technical solutions: a trimmer comprises a casing, a motor installed on the casing and a cooling fan connected to the motor; the cooling fan comprises a fan hub installed on the motor, a first blade protruding from the periphery of the fan hub and a second blade protruding from the first blade; the trimmer comprises an air inlet opened above the casing and an air outlet adjacent to the bottom of the cooling fan; cooling air flows into the motor from the air inlet and flows through the cooling fan to generate an air duct; the air duct comprises a first air duct formed by the rotation of the first blade and a second air duct formed by the rotation of the second blade; the cooling air of the first air duct and the second air duct converge and are discharged from the air outlet; the number K1 of the first blades and the number K2 of the second blades satisfy the following relationship: K1=K2 / n, where n is a natural number.

[0007] A further improvement is that the length L1 of the fan hub and the projected length L2 of the second blade satisfy the following relationship: 0.25L1≤L2≤0.5L1.

[0008] A further improvement is: the trimmer also includes a first bearing installed at one end of the casing, the first bearing is located between the fan hub and the air outlet, the hub diameter R4 of the first blade, the outer diameter R5 of the first bearing and the hub diameter R6 of the second blade satisfy the following relationship: R4≤(R5+3R4) / 4≤R6≤R5.

[0009] A further improvement is as follows: the first blade 32 is separated from the first bearing, the second blade is at least partially located between the first blade 32 and the first bearing, the second blade is adjacent to the first bearing, and a gap space is formed between the second blade and the first bearing, and the second air duct flows through the gap space to flow out of the air outlet.

[0010] A further improved solution is: the motor includes a rotating shaft and a stator mounted on the rotating shaft, and the diameter R1 of the stator and the hub diameter R4 of the first blade satisfy the following relationship: R4<R1.

[0011] A further improved solution is: the motor further comprises a rotor connected to the stator, and a hub diameter R3 of the first blade and a diameter R2 of the rotor satisfy the following relationship: R3>R2.

[0012] A further improved solution is: the ratio of the number K1 of the first blades to the number K2 of the second blades is: K1=K2.

[0013] A further improvement is that the first blade is configured as an axial flow blade, the second blade is configured as a centrifugal blade, and the airflow formed by the rotation of the second blade pushes the airflow formed by the rotation of the first blade radially and blows it toward the air outlet.

[0014] A further improved solution is that the second blade is away from the first bearing and is arranged on the inner edge of the second blade.

[0015] A further improved solution is that the length of the first blade extending in the radial direction is greater than the length of the second blade extending in the radial direction.

[0016] A further improved solution is that the second blade extends outward from the outer edge of the first blade, and the second blade is connected to the fan hub.

[0017] Compared with the prior art, the present invention has the following beneficial effects: through the second blade protruding from the first blade of the heat dissipation fan, the first air duct formed by the rotation of the first blade and the second air duct formed by the rotation of the second blade are combined and flow out from the air outlet, so as to achieve the heat dissipation of the whole machine and improve the user's operating experience; and the number of the first blades K1 and the number of the second blades K2 satisfy the following relationship: K1 = K2 / n, n is a natural number, the airflow in the low-speed vortex area can be smoothly discharged from the inside of the whole machine by the centrifugal force generated by the high-speed rotation of the second blade by the mainstream air of the first blade, thereby reducing the temperature of the motor winding. In addition, the first blade is an axial flow blade, the second blade is a centrifugal blade, and the second blade is adjacent to the first bearing and forms a gap space, the second air duct flows through the gap space to the air outlet, eliminates the low-speed vortex area formed by the airflow between the heat dissipation fan and the first bearing, and guides the airflow in the low-speed vortex area to the mainstream, so as to ensure that the cooling air is smoothly discharged from the inside of the whole machine and the first bearing does not fail due to overheating. [Drawings]

[0018] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings:

[0019] Figure 1 It is a structural schematic diagram of the edge trimming machine of the present invention;

[0020] Figure 2 yes Figure 1 A schematic cross-sectional view of the trimming machine shown;

[0021] Figure 3 yes Figure 2 A partial cross-sectional schematic diagram of the trimming machine shown;

[0022] Figure 4 yes Figure 1 A schematic cross-sectional view of the trimming machine in the direction of B is shown;

[0023] Figure 5 yes Figure 2 The structural schematic diagram of the embodiment 1 of the heat dissipation fan of the trimming machine shown;

[0024] Figure 6 yes Figure 1 The structural schematic diagram of the second embodiment of the heat dissipation fan of the trimming machine shown;

[0025] Figure 7 It is a schematic diagram of the structure of a heat dissipation fan of a trimming machine in the prior art;

[0026] Figure 8a It is the air duct streamline diagram of the prior art trimmer;

[0027] Figure 8b It is the air duct streamline diagram of the trimming machine of the present invention;

[0028] Figure 9a It is a temperature cloud diagram at the motor of the prior art trimming machine;

[0029] Figure 9b It is a temperature cloud diagram of the motor of the trimming machine of the present invention. [Specific implementation method]

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and implementation modes.

[0031] The terms used in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. For example, the words "upper", "lower", "front", "back", etc., which indicate the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0032] Embodiment 1

[0033] See also Figures 1 to 5 As shown, an embodiment of the present invention relates to a trimmer 100, which is used for trimming, grooving and other processing operations on wood and other workpieces. The trimmer 100 includes a housing 1, a motor 2 installed on the housing 1, an adjustment device 5 clamped on the outer peripheral surface of the housing 1, and an output unit 6 driven by the motor 2, and a cutter head (not shown) is installed on the output unit 6. Under the action of the driving source, the motor 2 drives the output unit 6 of the trimmer 100. When the operator performs processing operations, the adjustment device 5 is controlled to make the cutter head close to the workpiece, and the trimmer 100 is moved according to the required trajectory so that the cutter head trims the workpiece, and the trimmed dust is collected and processed by the dust collecting device 7 of the trimmer 100.

[0034] In this embodiment, the trimmer 100 further includes a cooling fan 3 connected to the motor. In addition, the trimmer 100 has an air inlet 10 opened on the upper part of the housing 1 and an air outlet 20 adjacent to the lower part of the cooling fan 3. When the trimmer 100 is working, the cooling fan 3 rotates to form a negative pressure, so that cooling air flows in from the air inlet 10 to generate an air flow duct, thereby cooling the heat generated by the motor 2 and other components.

[0035] Specifically, the trimmer also includes a first bearing 4 installed at one end of the housing 1, the cooling fan 3 includes a fan hub 31 installed on the motor 2, a first blade 32 protruding from the periphery of the fan hub 31, and a second blade 33 protruding from the first blade 32, the first bearing 4 is located between the fan hub 31 and the air outlet 20, the air duct includes a first air duct 101 formed by the rotation of the first blade 32 and a second air duct 102 formed by the rotation of the second blade 33, and the cooling air of the first air duct 101 and the second air duct 102 converge and flow out from the air outlet 20 to complete the heat dissipation of the trimmer 100. It should be noted that the first blade 32 is configured as an axial flow blade, and the second blade 33 is configured as a centrifugal blade. The airflow formed by the rotation of the second blade 33 pushes the airflow formed by the rotation of the first blade 32 in the radial direction and blows it toward the air outlet 20. The radially extending length of the first blade 32 is greater than the radially extending length of the second blade 33, that is, R3>R6, which prevents the cooling air from flowing smoothly in the first air duct 101 and the second air duct 102, thereby better realizing the heat dissipation of the motor.

[0036] Furthermore, the first blade 32 is spaced apart from the first bearing 4, the second blade 33 is at least partially located between the first blade 32 and the first bearing 4, the second blade 33 is adjacent to the first bearing 4, and a gap space 103 is formed between the second blade and the first bearing 4, the second air duct 102 flows through the gap space 103 to the air outlet 20, eliminating the low-speed vortex area formed by the airflow between the cooling fan 3 and the first bearing 4, and guiding the airflow in the low-speed vortex area to the mainstream, so as to ensure that the cooling air is smoothly discharged from the inside of the whole machine and the first bearing 4 does not fail due to overheating. It should be noted that the air outlet 20 is formed by the gap between the bearing seat installed on the first bearing 4 and the inner wall of the housing 1, which is conducive to the heat of the motor 2 being discharged from the bottom of the machine, improving the user's working experience.

[0037] In addition, the number K1 of the first blades 32 and the number K2 of the second blades 33 satisfy the following relationship: K1=K2 / n, where n is a natural number. In this embodiment, in order to smoothly discharge the airflow in the low-speed vortex region into the mainstream by means of the centrifugal force generated by the high-speed rotation of the second blades 33, it is preferred that the number K1 of the first blades 32 and the number K2 of the second blades 33 satisfy the following relationship: K1=K2.

[0038] See also Figure 2 and Figure 3As shown, in order to ensure that the optimal effect of the blade is not higher than the internal airflow of the first blade 32, the length L1 of the fan hub 31 and the projected length L2 of the second blade 33 satisfy the following relationship: 0.25L1≤L2≤0.5L1; the hub diameter R4 of the first blade 32, the outer diameter R5 of the first bearing 4 and the hub diameter R6 of the second blade satisfy the following relationship: R4≤(R5+3R4) / 4≤R6≤R5.

[0039] Please refer to Figure 4 and Figure 5 As shown, the second blade 33 extends outward from the outer edge of the first blade 32, and the second blade 33 is connected to the fan hub 31. The motor 2 includes a rotating shaft 21, a stator 22 mounted on the rotating shaft 21, and a rotor 23 connected to the stator 22. The housing 1 of the trimmer 100 is mostly a "straight-cylinder" body, and the "straight-cylinder" body allows the airflow to flow along the motor axis as a whole in the machine macroscopically. In order to force most of the cooling air to pass through the channel between the stator 22 and the rotor 23 to effectively cool the stator winding and the rotor winding, the diameter R1 of the stator 22 and the hub diameter R4 of the first blade 32 satisfy the following relationship: R4<R1; in addition, in order to ensure that the cooling fan 3 has a certain outer diameter to ensure that the fan blade has enough height to work on the airflow, the hub diameter R3 of the first blade 32 and the diameter R2 of the rotor 23 satisfy the following relationship: R3>R2.

[0040] Embodiment 2

[0041] See also Figure 6 As shown, in the second embodiment of the present invention, the overall structure of the trimmer is substantially the same as that of the first embodiment, but the difference is that the second blade 33' is far away from the first bearing 4' and is arranged at the inner edge of the second blade 33'.

[0042] Next, the advantages of the trimmer 100 proposed by the present invention will be introduced in detail.

[0043] See also Figure 5 and Figure 7 As shown, they are schematic structural diagrams of a heat dissipation fan of a trimming machine in the prior art and a heat dissipation fan of a trimming machine in the present invention; Figure 7 The heat dissipation effect of the heat dissipation fan of the prior art is average. The specific parameter comparison is shown in Table 1 below:

[0044]

[0045] It can be seen from Table 1 that the fan of the trimmer of the present invention has the following advantages compared with the heat dissipation fan of the prior art:

[0046] 1. In the simulation test, if Figure 8aAs shown in the prior art, the airflow near the blade root of the cooling fan will inevitably directly hit the downstream motor positioning bearing after the fan blades work and flow axially. In this way, the motor cooling air is prone to form a low-speed eddy flow area between the cooling fan and the bearing, and the hot air cannot be discharged smoothly, resulting in poor heat dissipation of the motor and excessive temperature rise of the winding. Figure 9a As shown, the bearing is damaged and heated by the air, which can easily cause the bearing to fail due to high temperature during long-term operation. In short, Figure 8a It can be clearly seen in FIG. 8 that there is an obvious vortex area formed by the hot air reflux and rotation between the cooling fan and the bearing; please refer to FIG. 8b, it can be clearly seen that since the centrifugal second blade is set on the cooling fan of the prior art, the low-speed turbine area between the cooling fan and the bearing can be eliminated, which is conducive to the smooth discharge of hot air. In addition, Figure 9b As shown, the highest temperature of the motor temperature cloud map is 105.66°C, while the highest temperature of the motor temperature cloud map in the prior art is 120.78°C, which greatly reduces the temperature at the motor, improves the heat dissipation efficiency, and improves the user experience.

[0047] 2. In actual working conditions, when the motor speed is 33000rpm, the rotor temperature in the prior art is 99.87K, while the rotor temperature in the present invention is 94.53K. Compared with before, the temperature is reduced by 5%, which effectively improves the situation of excessive motor temperature and ensures that the motor is well cooled.

[0048] To sum up, in the scheme of the present invention, a second blade is added to the first blade of the cooling fan to form a composite blade structure, so as to improve the situation where heat cannot be discharged in the low-speed eddy current area, realize heat dissipation of the whole machine, and improve the user experience during operation.

[0049] The present invention is not limited to the above specific embodiments. A person skilled in the art can easily understand that there are many alternatives to the trimmer of the present invention without departing from the principle and scope of the present invention. The protection scope of the present invention shall be subject to the content of the claims.

Claims

1. A trimmer, comprising a housing, a motor mounted on the housing, and a cooling fan connected to the motor; characterized in that: The cooling fan comprises a fan hub mounted on the motor, a first blade protruding from the periphery of the fan hub, and a second blade protruding from the first blade. The trimmer comprises an air inlet opened above the housing and an air outlet adjacent to the lower side of the cooling fan. Cooling air flows into the motor from the air inlet and flows through the cooling fan to form an air duct. The air duct comprises a first air duct formed by the rotation of the first blade and a second air duct formed by the rotation of the second blade. The cooling air of the first air duct and the second air duct are discharged from the air outlet after converging. The number K1 of the first blades and the number K2 of the second blades satisfy the following relationship: K1=K2 / n, where n is a natural number.

2. The trimming machine according to claim 1, characterized in that: The length L1 of the fan hub and the projection length L2 of the second blade satisfy the following relationship: 0.25L1≤L2≤0.5L1.

3. The trimming machine according to claim 1 or 2, characterized in that: The trimmer also includes a first bearing installed at one end of the casing, the first bearing is located between the fan hub and the air outlet, the hub diameter R4 of the first blade, the outer diameter R5 of the first bearing and the hub diameter R6 of the second blade satisfy the following relationship: R4≤(R5+3R4) / 4≤R6≤R5.

4. The trimming machine according to claim 3, characterized in that: The first blade 32 is spaced apart from the first bearing, the second blade is at least partially located between the first blade 32 and the first bearing, the second blade is adjacent to the first bearing, and a gap space is formed between the second blade and the first bearing, and the second air duct flows through the gap space to flow out of the air outlet.

5. The trimming machine according to claim 3, characterized in that: The motor includes a rotating shaft and a stator mounted on the rotating shaft, and a diameter R1 of the stator and a hub diameter R4 of the first blade satisfy the following relationship: R4<R1.

6. The trimming machine according to claim 5, characterized in that: The motor further includes a rotor connected to the stator, and a hub diameter R3 of the first blade and a diameter R2 of the rotor satisfy the following relationship: R3>R2.

7. The trimming machine according to claim 1, characterized in that: The ratio of the number K1 of the first blades to the number K2 of the second blades is: K1=K2.

8. The trimming machine according to claim 1, characterized in that: The first blade is configured as an axial flow blade, the second blade is configured as a centrifugal blade, and the airflow formed by the rotation of the second blade pushes the airflow formed by the rotation of the first blade radially and blows it toward the air outlet.

9. The trimming machine according to claim 3, characterized in that: The second blade is far away from the first bearing and is disposed at the inner edge of the second blade.

10. The trimming machine according to claim 1, characterized in that: A length of the first blade extending in the radial direction is greater than a length of the second blade extending in the radial direction.

11. The trimming machine according to claim 1, characterized in that: The second blade extends outward from an outer edge of the first blade, and the second blade is connected to the fan hub.

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