Processing device and electric motor for this

Abstract

Processing device (1) with: a rotary cutting tool (12); an electric motor (5) as a drive source for rotating the rotary cutting tool (12); a motor housing (51) adapted to accommodate the electric motor (50); and a stationary cover (14) designed to cover the rotary cutting tool (12), wherein the electric motor (50) is an external rotor type electric motor (50) having a stator (52) located within a rotor (53), the rotor (53) is attached to the motor shaft (54) via a rotor base (60), the rotor (53) is rotatably supported with respect to the stationary cover (14), the stator (52) is fixed to the motor housing (51) in such a way that it is not movable in the motor axis direction and is arranged inside the rotor (53), the machining device (1) further comprises a stator support portion (55) projecting into the motor housing (51) in the motor axis direction, and the stator (52) fixed to the stator support portion (55) near a distal end of the stator support portion (55), and the machining device (1) further comprises a stator fixing member (58) mounted on the stator support portion (55) for fixing the stator (52) to the stator support portion (55), thereby fixing the stator (52) so as not to be movable in the motor axis direction.

Description

[0001] The present invention relates to a machining device, such as a portable circular saw, a table saw or a grooving machine, and to an electric motor that can be suitably used in this machining device.

[0002] A circular saw with an electric motor is disclosed, for example, in US 2013 033 32 28 A1.

[0003] An electric motor that serves as a drive source for this type of machining device is, for example, an inner rotor type electric motor in which a rotor is arranged on the inner peripheral side of a stator, or an outer rotor type electric motor in which a rotor is arranged on the outer peripheral side of a stator. Compared with the inner rotor type electric motor, the outer rotor type electric motor has a rotor with a larger surface area, so it is possible to generate a large magnetic force and thus output a high torque. If the output torque of both types is the same, the outer rotor type electric motor can be made smaller than the inner rotor type electric motor. If the two motor types are set to the same size, the outer rotor type can output a larger torque than the inner rotor type.

[0004] Japanese Patent Publication No. JP 2012-176468 A discloses a machining apparatus using an external rotor-type electric motor as a drive source. The external rotor-type electric motor includes a stator and a motor shaft extending through the stator. The stator has one end located on an output side in the motor axis direction, and one end is fixed to a housing via a stator base. A rotor and a cooling fan are supported on one end of the motor shaft near the other end of the stator. A drive gear of a reduction gear train is attached to the other end of the motor shaft and is located on the output side. Rotational power of the electric motor is transmitted to a spindle via gear meshing between the drive gear and a driven gear, thereby rotating a rotary cutting tool.A motor housing, which houses the electric motor, is connected to a gearbox housing, which houses the reduction gear train. The gearbox housing is integrated into the back of the blade housing.

[0005] There is a need to improve the external rotor type electric motor, mainly in terms of disassembly and assembly properties. The stator is attached to the stator base, at a position closer to the cutting blade than the rotor. The stator base and the motor housing are connected together by a screw to the gear case. Thus, the stator base is not directly attached to the gear case. When the motor housing is removed at the time of disassembly of the electric motor, the stator base is also removed. The stator is separated from the motor housing and the stator base, and the stator is attracted by a magnet of the rotor to be integrated with the rotor.The magnetic force of the rotor magnet is large, so that in the state where the stator, which is not connected to the motor housing, and the rotor are mutually attracted as stand-alone units, the operation of separating the two from each other against the magnetic force is very difficult to perform.

[0006] Consequently, there is a need for an external rotor type electric motor with good disassembly property and good maintenance property, which is realized, for example, by the fact that the stator and the rotor can be easily separated from each other at the time of disassembly of the electric motor.

[0007] The above-mentioned object is achieved by a processing device according to claim 1 or 6.

[0008] According to one embodiment of the present teachings, a machining apparatus includes a rotary cutting tool and an electric motor as a drive source for rotating the cutting tool. A motor housing of the electric motor is connected to a stationary cover that covers the rotary cutting tool. The electric motor is an outer rotor type electric motor and has a stator located inside a rotor. The rotor is supported by a motor shaft at a position on the output side in the motor axis direction with respect to the stator. The rotor is mounted on the rotor base and rotatably supported on the stationary cover. The stator is fixed to the motor housing in such a way that it is immovable in the motor axis direction and is arranged on the inside of the rotor.

[0009] The stator is thus fixed to the motor housing, whereas the rotor is supported by the motor shaft at a position on the output side of the stator. Consequently, when the motor housing is separated from the stationary cover, the rotor remains with the stationary cover through the motor shaft. On the other hand, the stator is removed as a whole with the motor housing and separated from the rotor. In this way, when disassembling the electric motor, the stator can be simultaneously separated from the rotor in a state in which the motor housing is separated from the stationary cover. As a result, it is possible to improve the electric motor in terms of disassembly properties and, furthermore, in terms of maintenance properties.

[0010] Furthermore, the stator and rotor can be separated from the stationary cover integrally with the motor housing, while the stator and rotor adhere to each other by the magnetic force of a magnet. Even in this case, the stator is fixed to the motor housing in such a way that it is immovable in the motor axis direction. Consequently, the stator can be easily separated from the rotor against the magnetic force because the separation force can be applied by grasping the motor housing, which is larger than the stator. Then, the rotor can be easily removed from the stationary cover alone. A larger force can be applied by grasping the motor housing, which is larger than the stator. As a result, it is possible to easily separate the stator from the rotor against the magnetic force.

[0011] In contrast, in the conventional structure, the stator is not fixed to the motor housing in the motor axis direction. The motor housing is separated from the stationary cover, while the stator and rotor remain on the stationary cover. As a result, the stator and rotor are removed from the stationary cover side while adhering to each other as standalone units. In this case, it is very difficult to separate the extracted rotor and stator against the magnetic force. The stator and rotor as standalone units are smaller objects than the motor housing and the stationary cover, so it is necessary to exert a very large force to separate the stator and rotor as standalone units while directly grasping them. Consequently, the separation operation is very difficult to perform.

[0012] According to the embodiment, the stator can be separated from the stationary cover integrally with the motor housing. Therefore, even if the rotor and stator are separated from the stationary cover together, the stator can be easily separated from the rotor afterward by grasping the motor housing. Consequently, it is possible to improve the handling (disassembly property) at the time of disassembling the electric motor (separating the stator and rotor) and also achieve an improvement in maintenance properties.

[0013] According to another embodiment, the machining device may include a stator support portion that protrudes into the motor housing in the motor axis direction. The stator may be attached to the stator support portion near the distal end of the stator support portion.

[0014] Consequently, a fixing mechanism that fixes the stator to the stator support portion can be arranged on the inner side of the motor housing. This makes it possible to prevent the stator from being accidentally removed from the motor housing.

[0015] According to another embodiment, the machining device may include a stator fixing component mounted on the stator support portion for securing the stator to the stator support portion. The stator may be secured to the stator support portion in such a way that it cannot rotate about the motor axis, for example, by inserting a flat portion provided on the stator support portion into the inner peripheral side of the stator.

[0016] According to another embodiment, two bearings may be provided to rotatably support the motor shaft. One of the two bearings is located on the output side, and the other is located on the non-output side. The bearing on the non-output side may be held by the stator support portion or the stator fixing member. As a result, the stator support portion or the stator fixing member serves as the output support portion.

[0017] According to another embodiment, the rotor base may be provided with a plurality of impellers, whereby the rotor base serves as a cooling fan. This makes the electric motor compact in the motor axis direction.

[0018] According to another embodiment, the motor housing can be connected to a stationary cover, to which the rotor is previously mounted, so that the stator is arranged on the inner circumferential side of the rotor. Consequently, when the motor housing is separated from the stationary cover, the stator is simultaneously separated from the rotor. As a result, the electric motor can be disassembled quickly and easily, meaning the stator and rotor can be separated from each other quickly and easily.

[0019] According to another embodiment, the machining device may include a rotary cutting tool, an electric motor as a drive source for rotating the cutting tool, a motor housing that houses the electric motor, and a stationary cover that covers the cutting tool. The electric motor is an external rotor type electric motor having a stator located inside a rotor. The stator may be fixed to the motor housing or to the stationary cover in such a way that it is immovable in the motor axis direction. The motor housing may be separated from the stationary cover, while the stator and the rotor are mutually attracted by a magnetic force.

[0020] In the case where the stator is attached to the motor housing, the stator and rotor can be removed from the stationary cover together with the motor housing, while the stator and rotor are adhered to each other by magnetic force. The stator can be easily separated from the rotor along with the motor housing against the magnetic force, since the motor housing, which is larger than the stator, can be easily grasped to exert a separation force.

[0021] In the case where the stator is attached to the stationary cover, the stator and rotor can remain on the stationary cover, while the stator and rotor are mutually attracted by the magnetic force when the motor housing is separated from the stationary cover. The rotor can be easily separated from the stator along with the stationary cover against the magnetic force because the stationary cover, which is larger than the rotor, can be grasped to exert a separation force.

[0022] Another embodiment may be an electric motor for a machining device according to any one of the above-mentioned embodiments. The electric motor is of an external rotor type with a stator located inside a rotor. A rotor base supported by a motor shaft on an output side of the stator with respect to the motor axis direction may be provided, and the rotor may be mounted on the rotor base. The stator may be fixed to the inner side of the motor housing. With this structure, it is possible to improve the electric motor in terms of its disassembly property and its maintenance property.

[0023] Further objects, features, and advantages of the present teachings will be readily understood after reading the following detailed description together with the claims and the accompanying drawings. In the drawings: Fig. 1 is an overall perspective view of a machining apparatus according to an embodiment of the present teachings, having an electric motor as a power source; Fig. 2 a side view of the machining device, seen from the direction shown in Fig. 1 is indicated by an arrow (II); Fig. 3 is a plan view of the machining device, seen from the direction shown in Fig. 2 is indicated by an arrow (III), and a cross-sectional view of the electric motor therein; Fig. 4 is a front view of the machining device, seen from the direction shown in Fig. 2 is indicated by an arrow (IV); Fig. 5 is a vertical cross-sectional view of the processing device, cut along the section line VV in Fig. 2; Fig. 6 is a vertical cross-sectional view showing an electric motor according to a first embodiment; Fig. 7 is a vertical cross-sectional view showing an electric motor according to a second embodiment; and Fig. 8 is a vertical cross-sectional view showing an electric motor according to a third embodiment.

[0024] The preferred embodiments of the present teachings are described in detail below with reference to the accompanying drawings. Throughout the description, like reference numerals designate like elements with the same functionality, without repeating the description thereof.

[0025] The Fig. 1 to 5 show a machining device 1 according to an embodiment. This machining device 1 is a portable circular saw and includes a base 2 shaped like a flat plate, which is brought into contact with an upper surface of a workpiece W, and a tool main body 10 supported by an upper portion of the base 2.

[0026] The tool main body 10 includes an electric motor 50 as a drive source, a reduction gear train 20 for decelerating a rotational output of the electric motor 50, and a circular rotary cutting tool 12 mounted on a spindle 25 serving as the output shaft of the reduction gear train 20. A lower portion of the rotary cutting tool 12 protrudes from a lower surface of the base 2, and this protruding portion for performing the cutting operation is inserted into the workpiece W. The upper half of the rotary cutting tool 12 (the portion thereof above the base 2) is substantially covered by a stationary cover 14. The peripheral edge on the lower side of the rotary cutting tool 12, which protrudes below the lower surface 2, is covered by a movable cover 16.

[0027] In all drawings, the cutting direction is indicated by a thick arrow. By moving the machining device in the direction of the thick arrow, the rotary cutting tool 12 is inserted into the workpiece W. In the following description, with respect to the parts and components, the direction in which cutting occurs (the direction indicated by the thick arrow) is referred to as the front side or front area, and the opposite direction is referred to as the rear side or rear area. The user is located behind the machining device 1 and moves the machining device 1. The right-left direction of the parts and components is determined using the user as a reference. A motor shaft 54, which serves as the output shaft of the electric motor 50, extends in a direction that crosses (perpendicularly) the direction in which cutting occurs (i.e., in the right-left direction).

[0028] As in Fig. 4, a gear case 21, which houses the reduction gear train 20, is provided on a rear side (the left side as viewed from the user) of the stationary cover 14. A motor housing 51 of the electric motor 50 is connected to the gear case 21. As shown in Fig. 3, the electric motor 50 may be a brushless motor and / or an outer rotor type motor.

[0029] As in Fig. As shown in Fig. 5, a distal end of the motor shaft 54 ​​of the electric motor 50 protrudes from the motor housing 51 and extends into the reduction gear train 20. The reduction gear train 20 may constitute a single reduction mechanism in which a drive gear 22 and a driven gear 23 are in gear engagement with each other. The drive gear 22 is mounted on the motor shaft 54 ​​of the electric motor 50. The driven gear 23, which is in gear engagement with the drive gear 22, is mounted on the spindle 25. The distal end of the spindle 25 protrudes into the stationary cover 14. The rotary cutting tool 12 is mounted on the protruding portion while being held between a receiving flange 26 and a pressing flange 27. The gear housing 21 rotatably supports the spindle 25 via the bearings 28 and 29. The rotary cutting tool 12 rotates counterclockwise, viewed from the right side. As shown in Fig. 1, the direction of rotation of the rotary cutting tool 12 is indicated by an arrow 14a on the right side of the stationary cover 14.

[0030] The base 2 has a pivot support shaft 15 that supports the tool main body 10 so as to be vertically pivotable on the left side of the base 2. By changing the vertical pivot position of the tool main body 10 with respect to the base 2, the extent to which the rotary cutting tool 12 protrudes below the lower surface of the base 2 can be adjusted. As a result, it is possible to adjust the insertion depth of the rotary cutting tool 12 with respect to the workpiece W. An operation lever 5 is provided at the rear portion of the tool main body 10. Operating the operation lever 5 in the release direction allows the tool main body 10 to pivot vertically with respect to the base 2. Consequently, the insertion depth of the rotary cutting tool 12 can be changed. The vertical pivot position of the tool main body 10 is fixed by pivoting the operation lever 5 in the locking direction.This fixes the insertion depth of the rotary cutting tool 12.

[0031] The lower half of the rotary cutting tool 12, which protrudes below the lower surface of the base 2, is substantially covered by the movable cover 16. The stationary cover 14 supports the movable cover 16 such that the movable cover 16 is rotatable around the rotary cutting tool 12. As shown in Fig. As shown in Figure 2, the movable cover 16 is biased in the closing direction (counterclockwise direction) by a spring. The distal end of the movable cover 16 can contact the end of the workpiece W. In this contact state, the machining device 1 is moved in the cutting advancing direction indicated by the thick arrow in the drawing to advance the rotary cutting tool into the workpiece W. Consequently, the movable cover 16 is gradually opened against the elastic force of the spring biasing the movable cover 16. A handle 17 is mounted on the rear portion (rear portion) of the movable cover 16. The user grasps the handle 17 and can rotate the movable cover 16 against the spring force. This allows an operation such as replacing or removing the rotary cutting tool 12.

[0032] As in Fig. 4, a grip portion 30 is provided near the connection portion between the electric motor 50 and the reduction gear train 20. As shown in Fig. 2, the handle portion 30 has a chevron-looped configuration extending from the upper portion to the rear portion of the electric motor 50. The handle portion 30 includes an upright portion 31 extending upward from the upper portion of the electric motor 50, a main handle portion 32 extending rearward and downward from the upper portion of the upright portion 31, and a battery mounting portion 33 connecting the rear portion of the main handle portion 32 to the rear portion of the electric motor 50. The main handle portion 32 is a portion held by a user's hand, and a shift lever 35 is disposed on the lower surface of the main handle portion 32. A front handle portion 34 is provided on the upper portion of the upright portion 31 so as to protrude forward from the upright portion 31. The user can hold the front handle area 34 with the other hand.

[0033] Two battery packs 11 can be mounted on the battery mounting area 33, which is provided astride the rear area of ​​the main handle area 32 and the electric motor 50. The battery packs 11 are slid to the left (in Fig. 3 upwards) to be removed from the battery mounting area 33 and to the right (in Fig. 3 downwards) to be mounted on the battery mounting area 33. The removed battery packs 11 can be used repeatedly by recharging them with a separate charger. Using the battery packs 11 as a power source, the electric motor 50 is driven.

[0034] As mentioned above, an external rotor type electric motor can be used as the electric motor 50. The electric motor 50 has a stator 52 located within a rotor 53.

[0035] Fig. 6 shows in detail the electric motor 50 according to a first embodiment. The stator 52 is fixed at a position within the motor housing 51. The rotor 53 is supported by the motor shaft 54. The motor shaft 54 ​​is supported so as to be rotatable about the motor axis J via bearings 56 and 57. The bearing 56 on the output side (left side) with respect to the direction of the motor axis J is held by the gear case 21. The bearing 57 on the non-output side (right side) with respect to the direction of the motor axis J is held near the non-output side end portion of the motor housing 51. A ball bearing can be used as the bearing 56 on the output side with respect to the direction of the motor axis J. A needle bearing can be used as the bearing 57 on the non-output side with respect to the direction of the motor axis J.

[0036] The motor housing 51 is a resin component made by molding synthetic resin and is connected to the non-saw blade side of the gear case 21 by a plurality of fixing screws 51a. An air intake hole 51b or holes 51b are provided on the non-saw blade side end surface (non-output side end surface) of the motor housing 51. A housing cover 59 is further mounted on the non-saw blade side end surface of the motor housing 51. The housing cover 59 prevents the bearing 57 from detaching from the motor housing 51. The housing cover 59 protects a lead wire leading to the stator 52.

[0037] A stator support portion 55 having a cylindrical configuration is provided on the non-output-side inner surface of the motor housing 51. The stator support portion 55 protrudes from the center of the non-output-side inner surface toward the output side with respect to the direction of the motor axis J and is provided as a whole (integrated) with the motor housing 51. The center of the stator support portion 55 coincides with the motor axis J.

[0038] Flat portions 55a are provided on the distal end of the stator support portion 55. Each flat portion 55a is provided on the outer peripheral surface of the stator support portion 55 to form a narrow-width portion on the stator support portion 55. The narrow portion is inserted into an oval center hole 52a. As a result, the stator 52 is formed integrally with the stator support portion 55 with respect to the rotation direction. The inner peripheral hole of the stator support portion 55 extends therethrough toward the motor axis J. A screw hole 55b is provided at the saw blade-side portion of the inner peripheral hole. A retaining hole 55c is provided at the non-output-side portion of the inner peripheral hole.

[0039] A stator fixing member 58 is mounted on the distal end of the stator support portion 55. The stator fixing member 58 has a hexagonal head portion 58a, a circular flange portion 58d, and a screw shaft portion 58b. The screw shaft portion 58b is screwed through the screw hole 55b of the stator support portion 55 to mount the stator fixing member 58 to the stator support portion 55. The screw shaft portion 58b can be screwed into the stator support portion 55, for example, by means of a socket that engages the hexagonal head portion 58a. In this mounted state, the flange portion 58d of the stator fixing member 58 is held in contact with the right surface of the stator 52, and the stator 52 is fixed such that it cannot move in the direction of the motor axis J. The flat portions 55a of the stator support portion 55 are inserted into the oval center hole 52a, and the stator fixing member 58 is mounted.Consequently, the stator support portion 55 supports the stator 52 such that the stator 52 is unable to rotate about the motor axis J and move in the direction of the motor axis J.

[0040] An insertion hole 58c is provided in the stator fixing member 58 and extends through the stator fixing member 58 along the motor axis J. The motor shaft 54 ​​is inserted into the insertion hole 58c. The bearing 57, which supports the non-output side of the motor shaft 54, is held in a retaining hole 55c of the stator support portion 55. An aluminum rotor base 60 is located on the output side of the stator 52 around the motor axis J. The aluminum rotor base 60 is mounted on the motor shaft 54 ​​and can be mounted to the motor shaft 54 ​​via a steel bushing 61.

[0041] The steel bushing 61 has a lower thermal expansion coefficient than the aluminum rotor base 60. The steel bushing 61 is mounted on the inner peripheral hole of the rotor base 60. The bushing 61 is pressed into the inner peripheral hole of the rotor base 60 and firmly mounted to the rotor base 60. A pressing portion 54a of the motor shaft 54 ​​is pressed into the central hole 61a of the bushing 61, and the rotor base 60 is fixed to the motor shaft 54 ​​such that it is unable to rotate about the axis and move in the axial direction. The rotor base 60 is formed of aluminum to be lightweight. Although the steel bushing 61 is pressed into the motor shaft 54, the steel bushing 61 has a low thermal expansion coefficient to prevent thermal expansion. As a result, thermal expansion of the center hole 61a is prevented, thereby preventing the steel bushing 61 from detaching from the motor shaft 54.The support stability of the rotor base 60 with respect to the motor shaft 54 ​​is ensured.

[0042] The rotor 53 is connected along the peripheral edge of the rotor base 60. The rotor 53 has a cylindrical structure and protrudes toward the non-output side with respect to the direction of the motor axis J. The rotor 53 is fixedly mounted to the rotor base 60 by a plurality of bolts 53b. A magnet 53a, mounted on the inner peripheral surface of the rotor 53, is arranged around the stator 52 with a small gap therebetween.

[0043] A plurality of impellers 60a are formed on the rotor base 60. The impellers 60a form a cooling fan 62, which is integrally formed with the rotor base 60. The cooling fan 62 rotates integrally with the motor shaft 54. The rotation of the cooling fan 62 introduces external air through the air inlet hole 51b. The air inlet hole 51b is provided on the non-outlet end portion of the motor housing 51. The air flows into the motor housing 51 through the air inlet hole 51b, cools the electric motor 50, and passes between the impellers 60a.

[0044] The motor shaft 54 ​​extends along the motor axis J. One portion of the motor shaft 54 ​​extends into the motor housing 51, and the other portion protrudes from the motor housing 51 to the output side in the direction of the motor axis J. As mentioned above, the output side of the motor shaft 54 ​​penetrates the gear housing 21. The drive gear 22 is connected to the output end of the motor shaft 54. The rotation output of the electric motor 50 is transmitted to the spindle 25 via the gear engagement between the drive gear 22 and the driven gear 23, thereby rotating the rotary cutting tool 12.

[0045] As in the Fig. 3 and Fig. 4, a locking lever 13 is provided for locking or blocking the rotation of the motor shaft 54 ​​on the output side of the electric motor 50. As shown in the Fig. 1 and Fig. As shown in Figure 3, when the locking lever 13 is moved in its longitudinal direction, an oval locking hole 13a provided in the locking lever 13 engages with the flat portion 54b provided on the motor shaft 54. As a result, the rotation of the motor shaft 54 ​​is blocked. By blocking the rotation of the motor shaft 54, the rotation of the spindle 25 is blocked. This allows an operation such as replacing the rotary cutting tool 12.

[0046] As described above, the motor shaft 54 ​​supports the rotor base 60 on the output side (gearbox 21 side) of the stator 52. The rotor base 60 supports the rotor 53. With respect to the position in the motor axis J direction, the rotor 53 is arranged on the output side via the rotor base 60, and the stator 52 is arranged on the non-output side. In the step of assembling the electric motor 50, the motor shaft 54, to which the rotor base 60 and the rotor 53 have been mounted, is mounted on the stationary cover 14 side or the reduction gear train 20 side. Thereafter, the motor housing 51 is connected to the gear box 21. In this state, the stator 52 can be mounted on the inner peripheral side of the rotor 53. When the electric motor 50 is disassembled, the motor housing 51 is removed or separated from the gear box 21.At this time, it is possible to separate the stator 52 from the rotor 53 while maintaining the rotor 53 in the state where it is mounted together with the motor shaft 54 ​​on the side of the reduction gear train 20. This facilitates the separation of the stator 52 from the rotor 53 against the magnetic force of the magnet 53a because the rotor 53 is held on the gear case 21. In contrast, in the conventional structure, the stator is separated from the rotor after the stator and the rotor are removed from the motor case and the gear case. Consequently, it is possible to improve the disassembly property and, in addition, the maintenance property of the electric motor 50.

[0047] The stator 52 is fixed to the motor housing 51 by the stator fixing member 58. When the motor housing 51 is separated from the gear housing 21 or the stationary cover 14, the stator 52 is separated from the rotor 53 integrally with the motor housing 51. The stator 52 is separated from the rotor 53 against the magnetic force of the magnet 53a. However, the motor housing 51 is larger than the stator 52, so the user can more easily exert a large force on the stator 52 via the motor housing 51. Consequently, the stator 52 can be easily separated from the rotor 53 against the magnetic force. When the motor housing 51 is separated from the gear housing 21 or the stationary cover 14, the stator 52 is simultaneously separated from the rotor 53. This facilitates and / or speeds up the disassembly process.

[0048] When the motor housing 51 is separated from the gear case 21 or the stationary cover 14, the stator 52 and the rotor 53 can be separated from the gear case 21 or the stationary cover 14 integrally with the motor housing 51 while being mutually attracted by the magnetic force of the magnet 53a (magnetic force attraction state). Even in this case, the stator 52 is fixed to the motor housing 51, which is larger than the stator 52. Consequently, the stator 52 and the rotor 53 are easily separated because the user can easily grasp the motor housing 51 to separate the stator 52 from the rotor 53.

[0049] A conventional structure is known in which the stator is not fixed to the motor housing in the motor axis direction. In this conventional structure, the motor housing can be separated from the stationary cover while the stator and rotor remain on the stationary cover side. The stator and rotor are removed from the stationary cover side while being mutually attracted as stand-alone units. In this case, it is very difficult to separate the rotor and stator against the magnetic force attracting them both. The stator and rotor are objects smaller than the motor housing and the stationary cover. Consequently, a very large force is required to directly grasp and separate the stator and rotor. As a result, the operation of separating the stator and rotor from each other is very difficult to perform.

[0050] As described above, the stator 52 and the motor housing 51 can be handled integrally when the stator 52 and the rotor 53 are separated from each other. Consequently, the separation process is facilitated and / or accelerated because the user can easily grasp the motor housing 51, which is larger than the stator 52, to apply force for the separation process. Consequently, it is possible to improve the handling (disassembly property) at the time of disassembling the electric motor 50 (separating the stator 52 and the rotor 53) and also achieve an improvement in maintenance property.

[0051] A plurality of impellers 60a are formed on the rotor base 60. As a result, the rotor base 60 can serve as a cooling fan. Compared with a structure in which the cooling fan is separately supported on the motor shaft 54, the electric motor 50 can be made more compact in the direction of the motor axis J.

[0052] In the Fig. In the embodiment shown in Figure 6, the stator 52 is fixed to the motor housing 51. Alternatively, the stator may be fixed directly or indirectly to the stationary cover 14 such that it is immovable in the motor axis direction. With this configuration, the user can also grasp the stationary cover, which is larger and easily allows for the application of force to quickly and easily separate the stator and rotor. In this respect, this configuration enables an effect equivalent to that achieved with the above-mentioned configuration.

[0053] One in Fig. The embodiment shown in Fig. 7 has an electric motor 70 instead of the electric motor 50 according to Fig. 6. The same components as in the embodiment of Fig. 6 are designated by the same reference numerals, and a repeated description thereof is omitted. The electric motor 70 according to Fig. 7 has a stator fixing component 71 instead of the stator fixing component 58 of Fig. 6. The stator fixing component 71 regulates the movement of the stator 52 in the direction of the motor axis J.

[0054] In the embodiment according to Fig. 6, a flat portion 72a or flat portions 72a of a stator support portion 72 are inserted into the oval central hole 52a. As a result, the stator 52 is formed integrally with the stator support portion 72 such that it is unable to rotate and is supported by the stator support portion 72.

[0055] As in Fig. As shown in Figure 7, the stator fixing member 71 has a bearing holding portion 71a and a shaft portion 71b. The shaft portion 71b is pressed into a hole 72b provided in the stator support portion 72, and the stator fixing member 71 is fixed to the stator support portion 72. A fixing screw 73 is threaded through the stator fixing member 71. The fixing screw 73 is screwed along the motor axis J from the outer end of the non-output side of the motor housing 51. A head of the fixing screw 73 contacts the outer end of the stator support portion 72 and draws the stator fixing member 71 toward the stator support portion 72. The fixing screw 73 can hold the stator fixing member 71 on the inner end of the stator support portion 72.As a result, the stator fixing member 71 can be more firmly mounted to the stator support portion 72 to prevent rattling or detachment of the stator fixing member 71, in the broadest sense of the stator 52 with respect to the stator support portion 72.

[0056] The bearing holding portion 71a of the stator fixing member 71 holds a bearing 75. The bearing 75 supports the non-output end of the motor shaft 54, and the bearing 56, held in the gear housing 21, supports the output end of the motor shaft 54. The bearing 75 and / or the bearing 56 may be ball bearings. Furthermore, a bearing 74, mounted in the gear housing 21, supports the output end of the motor shaft 54. The bearing 74 may be a needle bearing. The bearing 56 and the bearing 74 are located on both sides of the drive gear 22 mounted on the motor shaft 54. Thus, the bearing 56 and the bearing 74 stably support the drive gear 22.

[0057] In the embodiment of Fig. 6, the motor shaft 54 ​​extends through an inner circumferential side of the stator fixing member 58 and the stator support portion 55. In contrast, in the embodiment of Fig. 7, the non-output side portion of the motor shaft 54 ​​extends only to the portion held by the bearing 75 and does not reach the stator support portion 72. The shaft portion 71b of the stator fixing member 71 and the fixing screw 73 pass through the inner peripheral side of the stator support portion 72, and the motor shaft 54 ​​does not pass therethrough.

[0058] Similar to the example of Fig. 6 supports the motor shaft 54 ​​of Fig. 7, the rotor base 60 is located on the output side of the stator 52 (on the gear case 21 side). The rotor base 60 supports the rotor 53. When the electric motor 70 is disassembled, the fixing screw 51a is loosened to detach the motor case 51 from the gear case 21. At this time, the stator 52 can be separated from the rotor 53, even though the rotor 53 is mounted on the reduction gear train 20 together with the motor shaft 54.

[0059] In the state where the motor housing 51 is separated from the gear housing 21 (the stationary cover 14 side), the rotor 53 and the stator 52 can be separated from the gear housing 21 even though they are mutually attracted by the magnetic force of the magnet. Therefore, the user can easily separate the rotor 53 against the magnetic force of the magnet by grasping the motor housing 51 and then applying a larger force.

[0060] Furthermore, in this operation, the fixing screw 73 does not need to be loosened, and the stator fixing member 71 remains mounted on the stator support portion 72 in the forced-in state. The stator 52 is held and fixed to the stator support portion 72. In this state, the stator 52 can be separated from the rotor 53 against the magnetic force by grasping the motor housing 51. Furthermore, both the stator 52 and the rotor 53 are fixed to the motor housing 51 or the stationary cover 14. This structure facilitates and / or accelerates the separation of the stator 52 from the rotor 53 compared to a structure in which at least the rotor and / or the stator are not fixed to the motor housing or stationary cover. In this regard, it is possible to achieve an improvement in the disassembly property and, furthermore, in the maintenance property of the electric motor 50.

[0061] An example of implementation as shown in Fig. 8, has an electric motor 80 instead of the electric motor 70 of Fig. 7. The shaft portion 71b of the stator fixing component 71 in Fig. 7 is pressed into the hole 72b of the stator support portion 72 to fix the stator fixing member 71 to the stator support portion 72. On the other hand, the stator fixing member 81 has Fig. 8 a carrier wave region 81 instead of the wave region 71b of Fig. 7. A stator support portion 82 is provided with an adjustment hole 82b instead of the hole 72b of Fig. 7. Similar to the carrier holding area 71a of Fig. 7, the stator fixing member 81 is provided with a bearing holding portion 81a for supporting the non-output side bearing 75, which supports the motor shaft 54. Similar to the embodiment of Fig. 7, the stator support portion 82 has a flat portion 82a or flat portions 82a, similar to the flat portion 72a, for integrating the stator 52 with respect to rotation. In the embodiment of Fig. 8 can the camp 74, which is in Fig. 7 and supports the output end of the motor shaft 54, can be omitted. In this respect, the embodiment of Fig. 8 equal to that of Fig. 6.

[0062] In the electric motor 80 of Fig. 8, the inner diameter of the adjustment hole 82b of the stator support portion 82 is set slightly larger than the outer diameter of the support shaft portion 81b of the stator fixing member 81. As a result, an appropriate gap is formed between the support shaft portion 81b and the adjustment hole 82b. Due to this gap, the stator fixing member 81 can be positionally adjusted in the radial direction (the direction perpendicular to the motor axis) with respect to the stator support portion 82. Consequently, it is possible to adjust the rear (left) end position of the motor shaft 54 ​​in the radial direction by loosening the fixing screw 73 and positionally adjusting the stator fixing member 81 in the radial direction. As a result, it is possible to prevent contact between the stator 52 and the rotor 53 (so-called core rubbing).

[0063] Similar to the examples of Fig. 6 and Fig. 7 is located in the electric motor 80 of Fig. 8, the rotor base 60 is located on the output side of the stator 52 in the direction of the motor axis J, and the rotor 53 is mounted on the rotor base 60. The stator 52 is fixed to a stator support portion 82 provided on the non-output side surface of the motor housing 51. To disassemble the electric motor 80, the fixing screw 51a is loosened to separate the motor housing 51 from the gear case 21. Next, the stator 52, which is fixed to the motor housing 51, is separated from the rotor 53 against the magnetic force of the magnet 53a. In this operation, it is not necessary to loosen the fixing screw 73, whereby the stator fixing member 81 remains fixed to the stator support portion 82. When the motor housing 51 is separated from the gear case 21, the non-output side end of the motor shaft 54 ​​is separated from the bearing 75.

[0064] In this way, the electric motor 80 is also Fig. 8, when the motor housing 51 is separated from the gear case 21, the stator 52 is simultaneously separated from the rotor 53. As a result, it is possible to improve the disassembly property of the electric motor 80 and, furthermore, the maintenance property of the electric motor. The rotor 53 can be separated from the gear case 21 or the stationary cover 14 together with the stator 52 by the magnetic force of the magnet when the motor housing 51 is separated from the gear case 21. Even in this case, the user can subsequently apply the force to separate the stator 52 from the rotor 53 by grasping the motor housing 51, which is larger than the stator 52. Consequently, the stator 52 can be separated from the rotor 53 more easily compared to a case where the stator 52 must be grasped directly to apply the force.

[0065] In the electric motors 50, 70 and 80 of the Fig. 6 to 8, the steel bushing 61 with a relatively small thermal expansion coefficient is pressed into the center of the rotor base 60, which is made of aluminum, for integration. The pressing portion 54 of the motor shaft 54 ​​is pressed into the central hole 61a of the bushing 61, whereby the rotor base 61 obtains better support stability with respect to the motor shaft 54. In the electric motors 50, 70, and 80 of the Fig. 6 to 8, the bushing 61 may be omitted, while the rotor base as a whole may be formed of steel.

[0066] In the examples of the Fig. 6 to 8, the rotor base 60 is provided with a plurality of impellers 60a, and the rotor base 60 can also serve as a cooling fan. Alternatively or additionally, a cooling fan can be provided or arranged on the motor shaft 54 ​​separately from the rotor base 60.

[0067] In the embodiment of Fig. 7, the bearing 74 supports the output end of the motor shaft 54, and the drive gear 22 is supported at both ends by bearings 74 and bearing 56. Alternatively, the bearing 74 may be omitted, while the drive gear 22 is supported in a cantilevered manner, similar to the embodiments of Fig. 6 and Fig. 8 can be supported.

[0068] The motor housing 51 can be formed of resin or aluminum. The motor housing 51 formed of aluminum can improve the dimensional accuracy of each portion of the motor housing 51.

[0069] As described above, the motor housing 51 formed of aluminum may be provided with the stator support portion 55, 72, or 82 integrally formed on the non-output side end surface of the motor housing 51. As described above, the stator support portion 55, 72, or 82 formed of aluminum may be provided with the flat portion(s) 55a, 72a, or 82a. The stator support portion 55, 72, or 82 may be provided with a shaft portion instead of the flat portion(s) 55a, 72a, or 82a. The shaft portion may be pressed into a circular central hole of the stator 52 to fix the stator 52 to the stator support portion 55, 72, or 82. In this structure, the stator 52 directly contacts the stator support portion formed of aluminum. Consequently, heat generated at the stator can be transferred to the stator support area and the motor housing.This improves the heat radiation properties of the electric motor.

[0070] As described above, the machining device 1 may be a so-called portable circular saw. Alternatively, the machining device may also be a so-called jib saw or table saw, in which a cutting tool is pushed into the workpiece placed on a table by moving the machining device main body relative to the table. The machining device may also be one of various types of other machining devices, such as a tilting circular saw, a diamond wheel, or a cutter configured to perform machining such as notching by rotating a cutting tool such as a grindstone. Also, the external rotor type electric motor described above is similarly applicable to such machining devices.

[0071] Various examples described in detail above with reference to the accompanying drawings are intended to be representative of the invention and not limiting thereof. The detailed description is intended to assist one skilled in the art in making, using, and / or practicing various aspects of the present teachings and, thus, is not intended to limit the scope of the invention. Moreover, each of the additional features and teachings disclosed above may be used separately or in combination with other features and teachings to provide improved fuel vapor processing devices and / or methods of making and using the same.

[0072] It is explicitly emphasized that all features disclosed in the description and / or the claims are to be considered separate and independent of each other for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, regardless of the feature combinations in the embodiments and / or the claims. It is explicitly stated that all range specifications or specifications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a limit of a range specification.

Claims

[1] Processing device (1) with: a rotary cutting tool (12); an electric motor (5) as a drive source for rotating the rotary cutting tool (12); a motor housing (51) adapted to accommodate the electric motor (50); and a stationary cover (14) designed to cover the rotary cutting tool (12), wherein the electric motor (50) is an external rotor type electric motor (50) having a stator (52) located within a rotor (53), the rotor (53) is attached to the motor shaft (54) via a rotor base (60), the rotor (53) is rotatably supported with respect to the stationary cover (14), the stator (52) is fixed to the motor housing (51) in such a way that it is not movable in the motor axis direction and is arranged inside the rotor (53), the machining device (1) further comprises a stator support portion (55) projecting into the motor housing (51) in the motor axis direction, and the stator (52) fixed to the stator support portion (55) near a distal end of the stator support portion (55), and the machining device (1) further comprises a stator fixing member (58) mounted on the stator support portion (55) for fixing the stator (52) to the stator support portion (55), thereby fixing the stator (52) so as not to be movable in the motor axis direction. [2] Machining device (1) according to claim 1, further comprising two bearings (56, 57) adapted to rotatably support the motor shaft (54), wherein one of the two bearings (56, 57) is located on a non-output side and is held by the stator support portion (55). [3] Machining device (1) according to claim 1, further comprising two bearings (56, 57) adapted to rotatably support the motor shaft (54), wherein one of the two bearings (56, 57) is located on a non-output side and is held by the stator fixing member (58). [4] Machining device (1) according to one of claims 1 to 3, wherein the rotor base (60) is provided with a plurality of impellers (60a), whereby the rotor base (60) serves as a cooling fan. [5] Machining device (1) according to one of claims 1 to 4, wherein the motor housing (51) is connected to the stationary cover (14) on which the rotor (53) is mounted such that the stator (52) is arranged on the inner peripheral side of the rotor (53). [6] Processing device (1) with: a rotary cutting tool (12); an electric motor (50) as a drive source for rotating the rotary cutting tool (12); a motor housing (51) adapted to accommodate the electric motor (50); and a stationary cover (14) adapted to cover the rotary cutting tool (12), wherein: the electric motor (50) is an external rotor type electric motor (50) having a stator (52) located within a rotor (53), the stator (52) is fixed to the motor housing (51) or to the stationary cover (14) in such a way that it is not movable in the motor axis direction, the motor housing (51) is designed to be separated from the stationary cover (14), while the stator (52) and the rotor (53) are mutually attracted by a magnetic force, the machining device (1) further comprises a stator support portion (55) projecting into the motor housing (51) in the motor axis direction, and the stator (52) fixed to the stator support portion (55) near a distal end of the stator support portion (55), and the machining device (1) further comprises a stator fixing member (58) mounted on the stator support portion (55) for fixing the stator (52) to the stator support portion (55), thereby fixing the stator (52) so as not to be movable in the motor axis direction. [7] Electric motor (50) for the machining device (1) according to one of claims 1 to 6.

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