power tools

Abstract

To provide an electric power tool in which a resin member of a rotor is not easily damaged.SOLUTION: An electric power tool includes a stator including a stator core, an insulator fixed to the stator core, and a coil held by the insulator, a rotor that is capable of rotating at 30,000 RPM or more relative to the stator, and includes a rotor core, a permanent magnet inserted into a hole in the rotor core, and a rotor having a resin member for fixing the rotor core and the permanent magnet, and an output unit driven by the rotor. The resin member has a ring-shaped portion protruding from the end surface of the rotor core, and a notch is provided in a part of the ring-shaped portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a power tool. [Background technology]

[0002] BACKGROUND ART In the technical field of power tools, a power tool having a motor, such as that disclosed in Patent Document 1, is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2014 / 0124231 Summary of the Invention [Problem to be solved by the invention]

[0004] The motor has a stator including a coil and a rotor with permanent magnets inserted into holes in the rotor core. The rotor has a resin member for fixing the rotor core and the permanent magnets. To correct the rotational balance of the rotor, it is possible to remove a portion of the resin member. In this case, the resin member is required to be resistant to breakage during rotor rotation. [Means for solving the problem]

[0005] This specification discloses a power tool including a stator having a stator core, an insulator fixed to the stator core, and a coil held by the insulator, a rotor capable of rotating at 30,000 RPM or more relative to the stator and having a rotor core, a permanent magnet inserted into a hole in the rotor core, and a resin member for fixing the rotor core and the permanent magnet, and an output unit driven by the rotor, the resin member having a ring-shaped portion protruding from an end face of the rotor core in a ring shape and having a notch in part of the ring-shaped portion. [Effects of the Invention]

[0006] The technology disclosed in this specification provides a power tool in which the resin member of the rotor is less likely to be damaged. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a power tool according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing the motor according to the embodiment. [Figure 3] FIG. 3 is a perspective view illustrating an example of a rotor according to the embodiment. [Figure 4] FIG. 4 is a perspective view illustrating an example of a rotor according to the embodiment. [Figure 5] FIG. 5 is a rear view of an example of a rotor according to an embodiment. [Figure 6] FIG. 6 is a view of an example of a rotor according to an embodiment, seen from above. [Figure 7] FIG. 7 is a cross-sectional view showing an example of a rotor according to the embodiment. [Figure 8] FIG. 8 is a diagram showing examples of the outer diameter, inner diameter, height, and cutting depth of the ring-shaped portion according to the embodiment. [Figure 9] FIG. 9 is a diagram showing a rotor according to a modified example. [Figure 10] FIG. 10 is a diagram showing a rotor according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] In one or more embodiments, the power tool includes a stator having a stator core, an insulator fixed to the stator core, and a coil held by the insulator; a rotor capable of rotating at 30,000 RPM or more relative to the stator and having a rotor core, a permanent magnet inserted into a hole in the rotor core, and a resin member for fixing the rotor core and the permanent magnet; and an output section driven by the rotor, wherein the resin member has a ring-shaped portion protruding in a ring shape from an end face of the rotor core, and a cutout portion may be provided in part of the ring-shaped portion.

[0009] In the above configuration, the resin member has a ring-shaped portion that protrudes from the end face of the rotor core, and a notch is provided in a portion of the ring-shaped portion, which allows the rotational balance of the rotor to be appropriately corrected. Furthermore, damage to the resin member can be appropriately prevented when the rotor rotates relative to the stator at 30,000 RPM or more. Therefore, a power tool having a resin member formed in an appropriate shape can be provided.

[0010] In one or more embodiments, the notch may be formed over a range of 180° or less around the rotational axis of the rotor.

[0011] In the above configuration, the cutouts are formed within an angle of 180° or less around the rotor shaft, ensuring the strength of the ring-shaped portion and thus preventing damage to the resin member when the rotor rotates relative to the stator at 30,000 RPM or more.

[0012] In one or more embodiments, the ring-shaped portion may have an uncut portion in contact with the end surface of the rotor core in the area where the cutout portion is formed.

[0013] In the above configuration, the ring-shaped portion has an uncut portion, which ensures the strength of the ring-shaped portion, and therefore, when the rotor rotates relative to the stator at 30,000 RPM or more, damage to the resin member can be appropriately prevented.

[0014] In one or more embodiments, the cutout may be curved at its base.

[0015] In the above configuration, the base of the notch is curved, ensuring the strength of the ring-shaped portion, and therefore, preventing damage to the resin member when the rotor rotates relative to the stator at 30,000 RPM or more.

[0016] In one or more embodiments, the uncut portion may have a height of 1 mm or more from the end face of the rotor core.

[0017] In this configuration, the height of the uncut portion from the end face of the rotor core is 1 mm or more, ensuring the strength of the ring-shaped portion and thus preventing damage to the resin member when the rotor rotates relative to the stator at 30,000 RPM or more.

[0018] In one or more embodiments, the notch may have a depth of 5 mm or less from the tip of the ring-shaped portion in the protruding direction.

[0019] In this configuration, the depth of the notch from the tip of the ring-shaped portion in the protruding direction is 5 mm or less, ensuring the strength of the ring-shaped portion and thus appropriately preventing damage to the resin member when the rotor rotates relative to the stator at 30,000 RPM or more.

[0020] In one or more embodiments, the outer diameter of the rotor core may be 30 mm or less, and the difference between the outer diameter and the inner diameter of the ring-shaped portion may be 6 mm or more.

[0021] In the above configuration, the outer diameter of the rotor core is 30 mm or less, and the difference between the outer and inner diameters of the ring-shaped portion is 6 mm or more, so the radial thickness of the ring-shaped portion is sufficiently secured relative to the outer shape of the rotor core, thereby appropriately preventing damage to the resin member when the rotor rotates relative to the stator at 30,000 RPM or more.

[0022] In one or more embodiments, the rotor has a fan that rotates integrally with the rotor core on one axial side of the rotation axis relative to the rotor core, and the ring-shaped portion may be arranged on the end face of the rotor core facing the fan.

[0023] In the above configuration, the ring-shaped portion is disposed on the end face of the rotor core on one side where the fan is disposed, so that the rotational balance can be appropriately corrected on that side of the rotor core.

[0024] In one or more embodiments, the ring-shaped portions may be disposed on both end surfaces of the rotor core in the axial direction of the rotation axis.

[0025] In the above configuration, the ring-shaped portions are disposed on both end faces of the rotor core in the axial direction of the rotation shaft, so that the rotational balance can be appropriately corrected on both sides of the rotor core.

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0027] In the embodiments, the positional relationship of each part is described using the terms "left," "right," "front," "rear," "upper," and "lower." These terms indicate relative positions or directions based on the center of the motor.

[0028] The power tool has a motor. In the embodiments, a direction parallel to the rotation axis AX of the motor is referred to as the axial direction, a direction radial from the rotation axis AX of the motor is referred to as the radial direction, a direction circumferentially around the rotation axis AX of the motor is referred to as the circumferential direction or the rotation direction, and a direction parallel to a tangent to an imaginary circle centered on the rotation axis AX of the motor is referred to as the tangential direction.

[0029] In the radial direction, a position or direction closer to the motor's rotation axis AX will be referred to as the radially inner side, and a position or direction farther from the motor's rotation axis AX will be referred to as the radially outer side. A position or direction on one side in the circumferential direction will be referred to as the one circumferential side, and a position or direction on the other side in the circumferential direction will be referred to as the other circumferential side. A position or direction on one side in the tangential direction will be referred to as the one tangential side, and a position or direction on the other tangential side will be referred to as the other tangential side.

[0030] 1 is a perspective view showing a power tool 100 according to this embodiment. In this embodiment, the power tool 100 is a circular saw. The power tool 100 includes a housing 101, a battery mounting portion 102, a motor 103, a controller 104, and a trigger switch 105.

[0031] The housing 101 has a motor accommodating section 111, a grip section 112, and a controller accommodating section 113. The motor accommodating section 111 accommodates the motor 103. An air intake 111A is arranged on the front surface of the motor accommodating section 111. The grip section 112 is arranged higher than the motor accommodating section 111 and the controller accommodating section 113. The controller accommodating section 113 accommodates the controller 104. The controller 104 controls the motor 103. The battery attachment section 102 is arranged on the right side of the grip section 112. The trigger switch 105 is arranged in the grip section 112.

[0032] The power tool 100 has a base 106 that contacts the top surface of the object to be cut (e.g., wood), a left support part 117 and a right support part 118 that connect the housing 101 and the base 106, a fixed cover 119 that is fixed to the housing 101, and a rotary blade 120 that rotates inside the fixed cover 119. When the motor 103 is driven, the rotary blade 120 rotates.

[0033] The motor 103 is a power source of the power tool 100. The motor 103 generates a rotational force for rotating the rotary blade 120. The motor 103 is a brushless motor.

[0034] Fig. 2 is an exploded perspective view showing an example of a motor 103. As shown in Fig. 2, the motor 103 has a stator 20 and a rotor 30 that rotates relative to the stator 20. The stator 20 is disposed around the rotor 30. The rotor 30 rotates around a rotation axis AX.

[0035] The stator 20 includes a stator core 21, a front insulator 22, a rear insulator 23, a coil 24, a power line 25, and a fusing terminal 26. The front insulator 22 and the rear insulator 23 may be fixed to the stator core 21 by integral molding.

[0036] The stator core 21 includes a plurality of stacked steel plates. The steel plates are made of a metal whose main component is iron. The stator core 21 is cylindrical. The stator core 21 has a plurality of teeth 21T that support the coils 24. The teeth 21T protrude radially inward from the inner surface of the stator core 21. In this embodiment, six teeth 21T are provided.

[0037] The front insulator 22 is an electrical insulating member made of synthetic resin. The front insulator 22 is disposed in front of the stator core 21. The front insulator 22 is cylindrical. The front insulator 22 has a plurality of protrusions 22T that support the coils 24. The protrusions 22T protrude radially inward from the inner surface of the front insulator 22. In this embodiment, six protrusions 22T are provided.

[0038] The rear insulator 23 is an electrical insulating member made of synthetic resin. The rear insulator 23 is disposed at the rear of the stator core 21. The rear insulator 23 is cylindrical. The rear insulator 23 has a plurality of protrusions 23T that support the coils 24. The protrusions 23T protrude radially inward from the inner surface of the rear insulator 23. In this embodiment, six protrusions 23T are provided.

[0039] The front end of the tooth 21T is connected to the rear end of the protrusion 22T, and the rear end of the tooth 21T is connected to the front end of the protrusion 23T.

[0040] The coils 24 are wound around the teeth 21T of the stator core 21 via the front insulators 22 and the rear insulators 23. A plurality of coils 24 are provided. In the embodiment, six coils 24 are provided. The coils 24 are wound around each of the plurality of teeth 21T via the protruding portions 22T and the protruding portions 23T. The coils 24 are arranged around the teeth 21T, the protruding portions 22T, and the protruding portions 23T. The coils 24 and the stator core 21 are insulated by the front insulators 22 and the rear insulators 23.

[0041] The multiple coils 24 are formed by winding a single wire. Circumferentially adjacent coils 24 are connected by a connecting wire 29, which is part of the wire. The connecting wire 29 is a wire that runs between one coil 24 and another coil 24. The connecting wire 29 is supported by the front insulator 22.

[0042] The battery pack 121 functions as a power supply unit for the motor 103. The battery pack 121 supplies a driving current to the motor 103 via the controller 104. The controller 104 controls the driving current supplied from the battery pack 121 to the motor 103. The driving current from the battery pack 121 is supplied to a power line via the controller 104.

[0043] The rotor 30 has a rotor core 31, a rotor shaft 32, and a permanent magnet 33. The rotor 30 rotates about a rotation axis AX. The rotor 30 can rotate relative to the stator 20 at 30,000 RPM or more.

[0044] 3 and 4 are perspective views showing an example of the rotor 30. FIGS. 3 and 4 show views from different angles. FIG. 5 is a view of the rotor 30 seen from behind. The fan 17 is not shown in FIGS. 4 and 5. FIG. 6 is a view of the rotor 30 seen from above. FIG. 7 is a cross-sectional view showing an example of the rotor 30. FIG. 7 is a cross-sectional view taken along line AA in FIG. 6. The rotor shaft 31 and components provided on the rotor shaft 31 are not shown in FIGS. 3 to 7. As shown in FIGS. 3 to 7, the rotor core 31 includes a plurality of stacked steel plates. The steel plates are metal plates whose main component is iron. The rotor core 31 is arranged to surround the rotation axis AX.

[0045] The rotor core 31 is substantially cylindrical. In this embodiment, the outer diameter of the rotor core 31 is, for example, 30 mm or less. The outer diameter X of the rotor core 31 is the distance between the rotation axis AX and the outer peripheral surface 31L of the rotor core 31. The rotor core 31 has a front end face 31F and a rear end face 31R. An opening 37 is formed in the center of the rotor core 31. The opening 37 is formed so as to penetrate between the end faces 31F and 31R of the rotor core 31.

[0046] The rotor shaft 32 extends in the axial direction. The rotor shaft 32 is disposed inside the rotor core 31. The rotor core 31 and the rotor shaft 32 are fixed together. The front portion of the rotor shaft 32 protrudes forward from an end face 31F of the rotor core 31. The rear portion of the rotor shaft 32 protrudes rearward from an end face 31R of the rotor core 31. The front portion of the rotor shaft 32 is rotatably supported by a front bearing (not shown). The rear portion of the rotor shaft 32 is rotatably supported by a rear bearing (not shown).

[0047] The rotary blade 120 described above is an output part of the power tool 100 that is driven directly or indirectly by the output gear 32A. The rotary blade 120 may be directly fixed to the rotor shaft 32. That is, the motor 103 may be configured to drive the rotary blade 120 by a so-called direct drive system. In this case, no reduction mechanism is provided between the motor 103 and the rotary blade 120. However, a reduction mechanism may be provided between the motor 103 and the rotary blade 120. That is, the rotary blade 120, which is the output part of the power tool 100, may be indirectly driven by the rotor 30. By providing a reduction mechanism, the rotary blade 120 can be driven with higher torque.

[0048] The permanent magnets 33 are fixed to the rotor core 31. In this embodiment, the permanent magnets 33 are arranged inside the rotor core 31. The motor 6 is an interior permanent magnet (IPM) motor. In this embodiment, four permanent magnets 33 are arranged around the rotation axis AX.

[0049] A sleeve 35 is disposed around the front portion of the rotor shaft 32. The sleeve 35 is fixed to the rotor shaft 32. The sleeve 35 is made of metal such as brass. The sleeve 35 functions as a balancer that corrects the rotational balance of the rotor 30 at the front portion of the rotor shaft 32. In other words, if the rotational balance of the rotor 30 is not good, part of the sleeve 35 is scraped off.

[0050] A fan 17 is fixed to the rear of the rotor shaft 32. The fan 17 is disposed rearward of the rotor core 31. At least a portion of the fan 17 is disposed in a position facing the end face 31R of the rotor core 31. When the rotor shaft 32 rotates, the fan 17 rotates together with the rotor shaft 32. As the fan 17 rotates, cooling air is introduced into the motor accommodating section 111 from the intake port 111A.

[0051] The rotor core 31 has a plurality of magnet holes 50 spaced apart in the circumferential direction. There are four magnet holes 50 in total. The magnet holes 50 are spaced apart in the circumferential direction at equal intervals. In a plane perpendicular to the rotation axis AX, the magnet holes 50 have the same shape. In a plane perpendicular to the rotation axis AX, the magnet holes 50 have the same dimensions.

[0052] The permanent magnets 33 are arranged in the magnet holes 50. A plurality of the permanent magnets 33 are arranged around the rotation axis AX. In the embodiment, four permanent magnets 33 are provided around the rotation axis AX. One permanent magnet 33 is arranged in each of the eight magnet holes 50. The permanent magnets 33 are plate-shaped. The permanent magnets 33 are rectangular parallelepiped-shaped. The permanent magnets 33 are long in the axial direction.

[0053] A gap is formed between the surface of the permanent magnet 33 placed in the magnet hole 50 and at least a portion of the inner surface of the magnet hole 50. A resin member 80 is placed in the gap. The resin member 80 has a filling portion 81 and a ring-shaped portion 82. The filling portion 81 fills the gap (see FIG. 7). By filling the gap, the filling portion 81 fixes the permanent magnet 33 in the magnet hole 50.

[0054] The ring-shaped portion 82 protrudes from one end face 31R of the rotor core 31 in the axial direction of the rotation axis AX. In this embodiment, the one side is the side on which the fan 17 is disposed, which is the rear side of the rotor core 31. The ring-shaped portion 82 is ring-shaped and centered on the rotation axis AX. The ring-shaped portion 82 has an outer peripheral surface 82B and an inner peripheral surface 82C (see FIG. 5). The outer peripheral surface 82B and the inner peripheral surface 82C are each cylindrical. The ring-shaped portion 82 has a thickness TH, which is the difference between the outer diameter LD and the inner diameter SD, and may be, for example, 6 mm or more. The outer diameter LD is the distance between the rotation axis AX and the outer peripheral surface 82B. The inner diameter SD is the distance between the rotation axis AX and the inner peripheral surface 82C. The thickness TH may be 5 mm or more. The ring-shaped portion 82 has a tip surface 82A. The tip surface 82A is the end face on the tip side in the protruding direction (rear) of the ring-shaped portion 82. The leading end surface 82A is, for example, flat. In the ring-shaped portion 82, a height LH from the end surface 31R of the rotor core 31 to the leading end surface 82A can be set to, for example, 6 mm.

[0055] The ring-shaped portion 82 has a cutout portion 83 and an uncut portion 84. The cutout portion 83 is a portion where a part of the ring-shaped portion 82 is cut out. The cutout portion 83 is formed, for example, by cutting the ring-shaped portion 82. The cutout portion 83 is provided in, for example, one location on the ring-shaped portion 82.

[0056] In ring-shaped portion 82, the weight of the portion where notch 83 is provided is lighter than the weight of the other portions in the direction around rotation axis AX. Therefore, by providing notch 83 at a position corresponding to the portion of rotor 30 that is heavier than the other portions in the direction around rotation axis AX, the rotational balance of rotor 30 can be corrected.

[0057] The angle θ of the cutout portion 83 in the direction around the rotation axis AX can be formed in accordance with the rotation balance of the rotor 30. For example, by placing the ring-shaped portion 82 without the cutout portion 83 on the end face 31R and measuring the rotation balance of the rotor 30 in this state, and then forming the cutout portion 83 at the angle θ corresponding to the weight at a position corresponding to the portion where the weight is heavier than the other portions, the rotation balance can be appropriately corrected.

[0058] The angle θ of the cutout portion 83 can be, for example, 180° or less. In this embodiment, the angle θ of the cutout portion 83 is 180°, but the present invention is not limited to this. The angle θ of the cutout portion 83 may be formed in a range of other angles, such as 30°, 45°, 60°, 90°, 120°, or 135°, around the rotation axis AX. Note that if there is no need to correct the rotational balance of the rotor 30, the cutout portion 83 may not be provided.

[0059] The uncut portion 84 is a portion that remains uncut when the cutout portion 83 is formed in the ring-shaped portion 82. The uncut portion 84 is provided in the range of the ring-shaped portion 82 where the cutout portion 83 is formed. The uncut portion 84 is in contact with the end face 31R of the rotor core 31. The cut surface 84A of the uncut portion 84 is flat. In the ring-shaped portion 82, the cutting height SH, which is the height from the end face 31R of the rotor core 31 to the cut surface 84A, can be, for example, 1 mm or more. Furthermore, the depth DP of the cutout portion 83, which is the height from the tip face 82A of the ring-shaped portion 82 to the cut surface 84A, can be 5 mm or less.

[0060] 8 is a diagram showing examples of the outer diameter LD, inner diameter SD, height LH, and cutting depth SH of the ring-shaped portion 82 according to this embodiment. In the following Examples 1 to 3, rotor cores 31 with outer diameters of 30 mm or less were used. In addition, the angle θ of the cutout portion 83 in the direction around the rotation axis AX was set to 180° in all cases.

[0061] In Example 1, when the ring-shaped portion 82 has an outer diameter LD of 21.0 mm, an inner diameter SD of 16.0 mm, a height LH of 6.0 mm, and a cutting height SH of 1.5 mm, the depth DP of the cutout portion 83 is 4.5 mm, and the volume (cutting volume) of the cutout portion 83 is 327 mm 3 In the ring-shaped portion 82 according to Example 1, even when the rotor 30 was repeatedly rotated at 32,000 RPM relative to the stator 20 a predetermined number of times, the ring-shaped portion 82 was not broken from the filling portion 81.

[0062] In Example 2, when the ring-shaped portion 82 has an outer diameter LD of 22.0 mm, an inner diameter SD of 16.0 mm, a height LH of 6.0 mm, and a cutting height SH of 1.5 mm, the depth DP of the cutout portion 83 is 4.5 mm, and the volume (cutting volume) of the cutout portion 83 is 403 mm 3 In the ring-shaped portion 82 according to Example 2, even when the rotor 30 was repeatedly rotated at 32,000 RPM relative to the stator 20 a predetermined number of times, the ring-shaped portion 82 was not broken from the filling portion 81.

[0063] In Example 3, when the ring-shaped portion 82 has an outer diameter LD of 23.0 mm, an inner diameter SD of 16.0 mm, a height LH of 6.0 mm, and a cutting height SH of 1.5 mm, the depth DP of the cutout portion 83 is 4.5 mm, and the volume (cutting volume) of the cutout portion 83 is 482 mm 3 In the ring-shaped portion 82 according to Example 3, even when the rotor 30 was repeatedly rotated at 32,000 RPM relative to the stator 20 a predetermined number of times, the ring-shaped portion 82 was not broken from the filling portion 81.

[0064] When using the above-described power tool 100, an operator grips the grip portion 112 and operates the trigger switch 105. When the trigger switch 105 is operated, power is supplied from the battery pack 121 to the motor 103, and the motor 103 starts. When the motor 103 starts, the rotor shaft 32 of the rotor 30 rotates. When the rotor shaft 32 rotates, the rotational force of the rotor shaft 32 is transmitted to the rotary blade 120, and the rotary blade 120 rotates.

[0065] In the power tool 100, a ring-shaped portion 82 is disposed on the end face 31R of the rotor core 31, and a cutout portion 83 is provided in the ring-shaped portion 82. The rotational balance of the rotor 30 is appropriately corrected by the cutout portion 83 of the ring-shaped portion 82. Therefore, the rotational balance of the rotor 30 can be appropriately corrected without disposing a sleeve made of brass or the like on the rear side of the rotor shaft 32.

[0066] Furthermore, in the power tool 100, the rotor shaft 32 can rotate at a high speed of 30,000 RPM or more relative to the stator 20. When the rotor shaft 32 rotates at such a high speed, stress is applied to the ring-shaped portion 82, making the filling portion 81 more susceptible to damage. In this embodiment, by setting the outer diameter LD, inner diameter SD, height LH, and cutting height SH of the ring-shaped portion 82 to the above-mentioned values, the ring-shaped portion 82 will not fly off from the filling portion 81 even when the rotor shaft 32 rotates at a high speed of 30,000 RPM or more relative to the stator 20.

[0067] As described above, in this embodiment, the power tool 100 includes a stator 20 having a stator core 21, a front insulator 22 and a rear insulator 23 fixed to the stator core 21, and a coil 24 held by the front insulator 22 and the rear insulator 23, a rotor 30 capable of rotating at 30,000 RPM or more relative to the stator 20 and having a rotor core 31, a permanent magnet 33 inserted into the magnet hole 50 of the rotor core 31, and a resin member 80 for fixing the rotor core 31 and the permanent magnet 33, and a rotary cutting tool 120 which is an output part driven by the rotor 30, wherein the resin member 80 has a ring-shaped portion 82 protruding in a ring shape from the end face 31R of the rotor core 31, and a cutout portion 83 is provided in a part of the ring-shaped portion 82.

[0068] In the above configuration, the resin member 80 has a ring-shaped portion 82 that protrudes in a ring shape from the end surface 31R of the rotor core 31, and the ring-shaped portion 82 has a cutout portion 83 formed in a portion thereof, which allows the rotational balance of the rotor 30 to be appropriately corrected. Furthermore, when the rotor 30 rotates at 30,000 RPM or more relative to the stator 20, damage to the resin member 80 can be appropriately prevented. Therefore, it is possible to provide a power tool 100 in which the resin member 80 of the rotor 30 is less likely to be damaged.

[0069] In this embodiment, the notch 83 is formed in a range of 180° or less around the rotation axis AX of the rotor 30.

[0070] In the above configuration, the range in which the notch 83 is formed is 180° or less in the direction around the rotation axis AX of the rotor 30, thereby ensuring the strength of the ring-shaped portion 82. Therefore, when the rotor 30 rotates relative to the stator 20 at 30,000 RPM or more, damage to the resin member 80 can be appropriately prevented.

[0071] In this embodiment, the ring-shaped portion 82 has an uncut portion 84 that contacts the end surface 31R of the rotor core 31 in the range where the notch portion 83 is formed.

[0072] In the above configuration, the ring-shaped portion 82 has the uncut portion 84, which ensures the strength of the ring-shaped portion 82. Therefore, when the rotor 30 rotates relative to the stator 20 at 30,000 RPM or more, damage to the resin member 80 can be appropriately prevented.

[0073] In this embodiment, the height of the uncut portion 84 from the end surface 31R of the rotor core 31 is 1 mm or more.

[0074] In the above configuration, the height of the uncut portion 84 from the end surface 31R of the rotor core 31 is 1 mm or more, which ensures the strength of the ring-shaped portion 82. Therefore, when the rotor 30 rotates relative to the stator 20 at 30,000 RPM or more, damage to the resin member 80 can be appropriately prevented.

[0075] In this embodiment, the notch 83 has a depth DP of 5 mm or less from the tip end surface 82A of the ring-shaped portion 82 in the protruding direction.

[0076] In the above configuration, the depth DP of the notch 83 from the tip end surface 82A in the protruding direction of the ring-shaped portion 82 is 5 mm or less, which ensures the strength of the ring-shaped portion 82. Therefore, when the rotor 30 rotates relative to the stator 20 at 30,000 RPM or more, damage to the resin member 80 can be appropriately prevented.

[0077] In this embodiment, the outer diameter of the rotor core 31 is 30 mm or less, and the thickness TH, which is the difference between the outer diameter LD and the inner diameter SD of the ring-shaped portion 82, is 6 mm or more.

[0078] In the above configuration, the outer diameter of the rotor core 31 is 30 mm or less, and the thickness TH, which is the difference between the outer diameter and the inner diameter of the ring-shaped portion 82, is 6 mm or more, so that the radial thickness of the ring-shaped portion 82 is sufficiently secured relative to the outer shape of the rotor core 31. Therefore, when the rotor 30 rotates relative to the stator 20 at 30,000 RPM or more, damage to the resin member 80 can be appropriately prevented.

[0079] In this embodiment, the rotor 30 has a fan that rotates integrally with the rotor core 31 on one axial side of the rotation axis relative to the rotor core 31, and the ring-shaped portion 82 is arranged on the end face 31R of the rotor core 31 facing the fan.

[0080] In the above configuration, the ring-shaped portion 82 is disposed on the end surface 31R of the rotor core 31 on one side where the fan is disposed, so that the rotational balance on that side of the rotor core 31 can be appropriately corrected.

[0081] The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, a configuration in which the root portion of the cutout portion 83 is angular has been described as an example, but this configuration is not limiting. FIG. 9 is a perspective view showing a rotor 130 according to a modified example. As shown in FIG. 9, in the rotor 130, the root portion 83B of the cutout portion 83 may have a curved shape. Because the root portion 83B of the cutout portion 83 is curved, the strength of the ring-shaped portion 82 can be ensured. Therefore, damage to the resin member 80 can be appropriately prevented when the rotor 30 rotates relative to the stator 20 at 30,000 RPM or more.

[0082] Furthermore, in the above embodiment, an example has been described in which the ring-shaped portion 82 is provided on the rear end face 31R of the rotor core 31, but the present invention is not limited to this configuration. Fig. 10 is a perspective view showing a rotor 230 according to a modified example. As shown in Fig. 10, in the rotor 230, the ring-shaped portion 82 may be disposed on end faces 31F, 31R on both sides in the axial direction of the rotation axis AX of the rotor core 31. Because the ring-shaped portion 82 is disposed on end faces 31F, 31R on both sides in the axial direction of the rotation axis AX of the rotor core 31, the rotational balance can be appropriately corrected on both sides in the axial direction of the rotation axis AX of the rotor core 31.

[0083] In the above-described embodiment, the power tool 100 is a circular saw. However, the power tool is not limited to a circular saw. Examples of the power tool include a driver drill, a percussion driver drill, an angle drill, an impact driver, a grinder, a hammer, a hammer drill, and a reciprocating saw.

[0084] In the above-described embodiment, the battery pack attached to the battery attachment portion is used as the power source for the electric working machine. However, a commercial power source (AC power source) may also be used as the power source for the electric working machine. [Explanation of symbols]

[0085] 17...fan, 20...stator, 21...stator core, 21T...teeth, 22...front insulator, 22T, 23T...protrusion, 23...rear insulator, 24...coil, 26...fusing terminal, 28...insulating member, 29...connecting wire, 30, 130, 230...rotor, 31...rotor core, 31F, 31R...end face, 32...rotor shaft, 33...permanent magnet, 35...sleeve, 37...opening, 50...magnet hole, 80...resin member, 81...filling portion, 82...ring-shaped portion, 82A...tip face, 8 2B...outer surface, 82C...inner surface, 83...cutout portion, 83B...base portion, 84...uncut portion, 84A...cutting surface, 100...power tool, 101...housing, 102...battery mounting portion, 103...motor, 104...controller, 105...trigger switch, 106...base, 111...motor accommodating portion, 112...grip portion, 113...controller accommodating portion, 117...front support portion, 118...rear support portion, 119...fixed cover, 120...rotary cutting tool, 121...battery pack, AX...rotating shaft

Claims

1. a stator including a stator core, an insulator fixed to the stator core, and a coil held by the insulator; a rotor capable of rotating at 30,000 RPM or more relative to the stator, the rotor having a rotor core, permanent magnets inserted into holes in the rotor core, and a resin member for fixing the rotor core and the permanent magnets; an output section driven by the rotor; the resin member has a ring-shaped portion protruding from the end surface of the rotor core, a notch portion provided in a part of the ring-shaped portion, and an uncut portion in contact with the end surface of the rotor core within a range where the notch portion is formed; the notch is provided at one location in the circumferential direction of the ring-shaped portion, The uncut portion has an arc shape in which a part of the ring shape of the ring-shaped portion is cut away by the notch portion. Power tools.

2. The notch is formed in a range of 180° or less around the rotation axis of the rotor. The power tool according to claim 1 .

3. The notch has a curved base. The power tool according to claim 1 .

4. The uncut portion has a height of 1 mm or more from the end face of the rotor core. The power tool according to claim 1 .

5. The notch has a depth of 5 mm or less from the tip of the ring-shaped portion in the protruding direction. The power tool according to claim 1 .

6. The outer diameter of the rotor core is 30 mm or less, The difference between the outer diameter and the inner diameter of the ring-shaped portion is 6 mm or more. The power tool according to claim 1 .

7. the rotor has a fan that rotates integrally with the rotor core on one side of the rotor core in the axial direction of the rotation shaft, The ring-shaped portion is disposed on the one end surface of the rotor core. The power tool according to claim 1 .

8. The ring-shaped portions are disposed on both end surfaces of the rotor core in the axial direction of the rotation shaft. The power tool according to claim 1 .

9. a stator including a stator core, an insulator fixed to the stator core, and a coil held by the insulator; a rotor capable of rotating at 30,000 RPM or more relative to the stator, the rotor having a rotor core, permanent magnets inserted into holes in the rotor core, and a resin member for fixing the rotor core and the permanent magnets; an output section driven by the rotor; the resin member has an inner circumferential surface in contact with the end face of the rotor core, an outer circumferential surface in contact with the end face of the rotor core, and a tip end surface in contact with the inner circumferential surface and the outer circumferential surface, A notch is provided that is deeply cut from the tip surface to the inner peripheral surface and the outer peripheral surface within a range of 180 degrees or less. Power tools.

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