A motor for a power tool with adjustable stator inner diameter

Abstract

The present invention provides a motor for a power tool with an adjustable inner diameter of the stator. The motor includes a stator assembly and a rotor assembly disposed within the stator assembly. The stator assembly includes: a stator yoke, with a plurality of slots evenly disposed on its inner side, and at least one side wall of the slot is provided with a first tooth portion; a plurality of stator teeth, which include a base portion and a shoulder integrally formed therewith, and at least a part of a second tooth portion is disposed on one side surface portion of the base portion. One side of the base portion is embedded into the slot, and at least a part of the second tooth portion disposed on one side surface of the base portion meshes with the first tooth portion. In this way, during the large-scale production of the motor, for stator assemblies of the same size, only the stator yoke and stator teeth need to be mass-produced, and during assembly, assembly can be carried out according to the calculated tooth-yoke clearance. This improves the production design efficiency and further improves the economy of motor production. In addition, in this embodiment, the power density of the finalized motor can be further improved by finely adjusting the tooth-yoke clearance, maximizing the performance of the motor.

Description

Technical Field

[0001] The present invention relates to a motor, and more particularly to a motor for a power tool with an adjustable inner diameter of the stator. Background Art

[0002] With the maturity of motor technology, more and more brushless motors are applied to power tools. In the stator structure of the motors used in current power tools, most of them adopt an integral stator structure as Figure 1 described. In the figure, the diameter of the stator is a fixed value, that is, the ratio of the outer diameter of the stator to the inner diameter of the stator is a fixed value. Thus, when the inner diameter of the stator is fixed, the power of motors on the same platform is basically the same, and the change range of the torque is basically small. When a strong power range is required for a motor in some occasions, such as when the motor outputs a large torque, or when a high-speed motor is desired with small vibration, or when the motor operates under high-speed and low-vibration conditions, etc., each such type of motor needs to be separately tooled. In this case, the economy is low when multiple types of motors are needed, and the requirements cannot be met. Summary of the Invention

[0003] The purpose of the present invention is to solve at least one of the above technical defects. Based on the above problems, the present invention provides a motor whose inner diameter of the stator can be changed. By adjusting the distance L, the inner diameter of the stator changes, and a stronger power range can be obtained.

[0004] For this reason, the present invention adopts the following technical solutions.

[0005] A motor for a power tool with an adjustable inner diameter of the stator, characterized in that it comprises a stator assembly and a rotor assembly disposed within the stator assembly.

[0006] The stator assembly comprises:

[0007] A stator yoke, on the inner side of which a plurality of slots are evenly arranged, and at least one side wall of each slot is provided with a first tooth portion.

[0008] Stator teeth, which comprise a base portion and a shoulder integrally formed therewith. A second tooth portion is provided on a part of one side surface of the base portion, and a part of the second tooth portion on one side of the base portion embedded in the slot meshes with a part of the first tooth portion.

[0009] Preferably, first tooth portions are respectively provided on both side walls of the slot; second tooth portions are provided on parts of both side surfaces of the base portion, and a part of the second tooth portion on one side of the base portion embedded in the slot meshes with a part of the first tooth portion.

[0010] Preferably, the second tooth portion is provided with a plurality of parallel protrusions at equal intervals.

[0011] Preferably, the protrusions are triangular or square.

[0012] Preferably, 9 slots are evenly arranged on the inner side of the stator yoke.

[0013] Preferably, the included angle between both ends of the shoulder is between 5° and 30°.

[0014] Preferably, the number of the slots is greater than or equal to the number of the stator teeth.

[0015] Preferably, the ratio of the length of the second tooth part to the length of the base part is between 0.1 and 0.5.

[0016] Preferably, a plurality of teeth are provided in the second tooth part, and the distance between two adjacent teeth is between 0.1 mm and 1.0 mm.

[0017] Preferably, a plurality of convex parts or concave parts are evenly arranged on the outer circumference of the stator yoke in the circumferential direction, and the ratio of the length of the convex part or concave part in the circumferential direction to the length of the slot is between 0.1 and 1

[0018] Advantages of the present invention compared with the solutions in the prior art:

[0019] For the motor adopting the implementation mode of the present application, the inner diameter of the stator is adjustable. The L distance can be changed to realize the change of the inner diameter of the stator: for example, when increasing the output torque of the motor, the inner diameter becomes smaller, and it is easier for the motor to achieve high speed and low vibration conditions. In mass production, only the stator yoke and stator teeth need to be mass-produced, and during assembly, assembly can be carried out according to the calculated tooth-yoke clearance. This implementation mode can also further optimize the finalized motor and improve its power density. Description of the Drawings

[0020] The present invention will be further described below with reference to the drawings and embodiments:

[0021] Figure 1 is a schematic structural diagram of an existing motor stator;

[0022] Figure 2 is a schematic structural diagram of the stator assembly of the embodiment of the present invention;

[0023] Figure 3 is Figure 2 an enlarged schematic diagram of the stator teeth in

[0024] Figure 4 , Figure 5 is a schematic structural diagram of the stator yoke of the embodiment of the present invention. Detailed Embodiments

[0025] The above solutions will be further described below with specific embodiments. It should be understood that these embodiments are for illustrating the present invention and not for limiting the scope of the present invention. The implementation conditions adopted in the embodiments can be further adjusted according to the conditions of specific manufacturers, and the implementation conditions not specified are usually those in conventional experiments.

[0026] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes.

[0027] Embodiment:

[0028] An embodiment of the present application provides a stator assembly, which includes a stator yoke, with a plurality of slots arranged at intervals on its inner side, a first tooth portion is arranged on the side wall of the slot, and a plurality of stator teeth, and second tooth portions that cooperate with the first tooth portions of the slots on the inner side of the stator yoke are respectively arranged on both sides of one end of the stator teeth. During assembly, through the cooperation of the first tooth portion and the second tooth portion, the stator teeth are installed on the stator yoke. In this way, the distance from the end of the second tooth portion side of the stator tooth to the bottom of the slot is adjustable (that is, the tooth-yoke gap L is adjustable). The advantage of such a design is that during large-scale production, for stator assemblies of the same size, only the stator yoke and stator teeth need to be mass-produced, and during assembly, assembly can be carried out according to the calculated tooth-yoke gap. This improves the production design efficiency and thus improves the economy of the motor. In addition, this embodiment can also further optimize the finalized motor by finely adjusting the tooth-yoke gap to further improve its power density.

[0029] Next, in combination with Figures 2 - 5 to describe the motor according to the embodiment of the present invention. Moreover, the drawings include schematic diagrams, and there will be situations where the scale and the vertical and horizontal ratios of each component are different from the actual ones.

[0030] As Figure 2 shown is a cross-sectional schematic diagram of the stator assembly according to the embodiment of the present application. The stator assembly 100 includes a stator yoke 101 and a plurality of stator teeth 102. A plurality of slots 101a are circumferentially and uniformly arranged on the inner side of the stator yoke 101, and the slots 101a are used to fix the stator teeth 102; the stator teeth 102 include a base portion 102a, one side portion of which is embedded in the slot 101a, and the gap between the end of the base portion 102a and the bottom of the slot 101a is adjustable. The other end of the base portion 102a is connected to a shoulder.

[0031] As Figure 3The figure shows a schematic diagram of the structure of the stator tooth of the embodiment of the present application. The stator tooth 102 includes a base 102a and a shoulder 102b. The base 102a and the shoulder 102b are integrally formed. The opposite side surface portions of the base 102a are provided with a second tooth portion 102a1, which is embedded in the slot of the stator through the second tooth portion 102a1. In the present embodiment, the second tooth portion 102a1 is arranged in the middle and lower part of the base (i.e., close to the end face 102a2). Preferably, the ratio of the second tooth portion 102a1 to the base 102a is between 0.10 and 0.50 (y upward). The second tooth portion 102a1 is provided with a plurality of teeth (preferably, the spacing between two adjacent teeth is between 0.1 mm and 1.0 mm, such as 0.1 mm, 0.2 mm, 0.5 mm, 0.6 mm, 1.0 mm, etc., so that the tooth yoke gap L from the end face 102a2 to the bottom of the slot can be adjusted by adjusting the number of teeth moved upwards in y and then embedded into the slot, and the inner diameter of the stator assembly can be accurately adjusted). In the embodiment, the teeth are arranged in a triangle or rectangle, and the spacing between two adjacent teeth is between 0.1 mm and 1.0 mm.

[0032] In one embodiment, at least one side portion of the base 102a in the y direction is provided with a second tooth portion 102a1. Preferably, the second tooth portion 102a1 extends from the side close to the end surface 102a2 to the middle area of ​​the side of the base. At least one side portion of the groove circumference is provided with a first tooth portion that cooperates with the second tooth portion.

[0033] like Figure 4 , Figure 5 The structure diagram of the stator yoke of the embodiment of the present application is shown, wherein a plurality of slots 101a are arranged on the inner circumference, and the circumferential side walls of the slots are respectively arranged with first teeth 101a1. The angle between the two ends of the slot and the center of the circle is between 5° and 30°, preferably, 10°, 15°.

[0034] In one embodiment, a first tooth portion 101a1 is disposed on one circumferential side wall of the slot. In this embodiment, the stator yoke is configured with 9 slots. In other embodiments, the number of slots is not limited, depending on the specific application. The advantage of such a design is that multiple slots can be preset, and the number of stator teeth can be different from the slots, which satisfies the rapid mass production of various types of stator components. Preferably, a plurality of convex or concave portions are uniformly disposed on the outer circumference of the stator yoke. Further, the sum of the convex and concave portions is consistent with the number of slots. Further, the slot is directly opposite the convex or concave portion. The ratio of the length of the convex or concave portion on the circumference of the stator to the slot is between 0.1 and 1. Preferably, the ratio of the length of the convex or concave portion on the circumference of the stator to the slot is between 0.2 and 0.5. The circumferential center of the convex and concave portion is consistent with the circumferential center of the slot. In one embodiment, the convex or concave portion is used to play a fixing role when the motor and the tool are matched.

[0035] The motor equipped with the above stator assembly is a brushless motor, which can be used in electric tools such as lawn trimmers, blowers and vacuums, self-propelled lawn mowers, and hammer drills. Its stator inner diameter is adjustable. By changing the stator inner diameter, the optimization of the motor output can be achieved. In this way, when producing motors of the same size, there is no need to make a mold for each type of motor, thus shortening the development cycle.

[0036] The above embodiments are only used to illustrate the technical concept and characteristics of the present invention. The purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A motor for an electric tool with adjustable stator inner diameter, characterized in that, It includes a stator assembly and a rotor assembly disposed within the stator assembly. The stator assembly includes: A stator yoke, with a plurality of slots evenly arranged on its inner side, and a first tooth portion is arranged on at least one side wall in the circumferential direction of the slot. A plurality of stator teeth, which include a base portion and a shoulder integrally formed therewith. A second tooth portion is arranged on a partial surface of one side of the base portion. One side of the base portion is embedded into the slot, and at least a part of the second tooth portion arranged on one side surface of the base portion meshes with the first tooth portion. The first tooth portions are respectively arranged on both side walls of the slot; second tooth portions are arranged on partial surfaces of both sides of the base portion, and a part of the second tooth portion embedded into the slot on one side of the base portion meshes with a part of the first tooth portion. A plurality of teeth are arranged in the second tooth portion, and the distance between adjacent teeth is between 0.1 mm and 1.0 mm.

2. The motor for an electric tool with adjustable stator inner diameter according to claim 1, characterized in that, A plurality of equally spaced and parallel protrusions are arranged on the second tooth portion.

3. The motor for an electric tool with adjustable stator inner diameter according to claim 2, characterized in that, The protrusions are triangular or square.

4. The motor for an electric tool with adjustable stator inner diameter according to claim 1, characterized in that, Nine slots are evenly arranged on the inner side of the stator yoke.

5. The motor for an electric tool with adjustable stator inner diameter according to claim 1, characterized in that, The included angle between both ends of the shoulder is between 5° and 30°.

6. The motor for an electric tool with adjustable stator inner diameter according to claim 1, characterized in that, The number of the slots is greater than or equal to the number of the stator teeth.

7. The motor for an electric tool with adjustable stator inner diameter according to claim 1, characterized in that, The ratio of the length of the second tooth portion to the length of the base portion is between 0.1 and 0.

5.

8. The motor for an electric tool with adjustable stator inner diameter according to claim 1, characterized in that, A plurality of convex portions or concave portions are evenly arranged on the outer circumference of the stator yoke in the circumferential direction, and the ratio of the length of the convex portion or concave portion in the circumferential direction to the length of the slot is between 0.1 and 1.

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