JP5376201B2 - Electric tool - Google Patents

Description

  The present invention relates to a power tool, and more particularly to a motor that drives the power tool.

A stator of a two-pole commutator motor used for an electric tool is composed of a stator core having a magnetic pole and a yoke constituting the stator, and a coil bundle wound around a slot formed in the stator core. Has been. When configuring this stator, as disclosed in Patent Document 1, there is a method of assembling after winding and forming the coil bundle into a slot of the divided stator core. According to this method, the coil bundle can be wound in an aligned manner for reasons that are not limited by the dimensions of the stator core, and a stator having the coil bundle wound in an aligned manner can be produced. For this reason, the air which functions as a heat insulating material inside the coil bundle is reduced, and the increase in the temperature of the stator is reduced by the increase in the thermal conductivity accompanying the reduction of the air, thereby improving the output of the product.
JP-A-8-65979

  In performing the above assembly method, in order to install the coil bundle as large as possible formed by aligned winding in a limited size slot without breaking, at least the stator core magnetic pole and yoke are divided. Divided cores of three or more are common. However, since the three-part stator core needs to be divided into a cylindrical or arc-shaped yoke and magnetic pole, it is larger than a conventional stator core that is divided into two by a split surface passing through the cylindrical axial direction. There was a problem that the number of man-hours during assembly increased.

  Further, the radial position of the stator with respect to the rotor is generally determined by the position of the yoke with respect to the rib provided in the housing incorporating the motor. For this reason, when the magnetic pole and the yoke are divided, it is necessary to increase the accuracy between the magnetic pole and the yoke in addition to the accuracy between the yoke and the rib. As a result, there has been a problem in that the positional accuracy of the magnetic poles is reduced and the motor output is reduced. Therefore, an object of the present invention is to provide an electric tool including a motor in which a coil bundle as large as possible is mounted on a small stator core with a reduced number of divisions.

In order to solve the above problems, the present invention includes a housing and a motor that is disposed in the housing and drives a tip tool, and the motor is configured by combining a plurality of divided cores having slots. A stator, a plurality of coil portions mounted on the stator, and a rotor rotatably disposed within the stator, each of the plurality of coil portions being mounted on the stator Each of the plurality of split cores has a yoke portion located on one end side in the circumferential direction of the stator and a yoke portion located on the other end side and integrated with the yoke portion. A pair of arm portions that extend from the magnetic pole portion and extend to one side and the other side in the circumferential direction of the rotor, and are provided on the outer peripheral side of the arm portion on the yoke side. It has an arcuate mounting surface, and the arm part on the yoke side It said slot in a space surrounded by the serial yoke portion is formed, in a state where the split cores are split, the coil portion is configured to be received in the slot to move along the mounting surface in which it provides an electric tool.

  According to such a configuration, the coil portion can be attached to the magnetic pole portion in a state where it is divided into the split cores and there is no yoke portion on the other end side extending from the magnetic pole portion. As a result, the coil portion is not caught by the yoke portion on the other end side, so that the largest coil portion can be mounted in a small slot of a small divided core. In addition, since at least the yoke portion on one end side and the magnetic pole portion are integrated, the positional accuracy of the magnetic pole portion with respect to the yoke portion can be increased, and a decrease in motor output can be suppressed.

  In the electric tool configured as described above, it is preferable that a mounting surface on which another bonding portion is mounted is formed on the bonded portion, and the mounting surface is configured with an expansion start position of the arm portion as an edge. .

  According to such a structure, it becomes a structure joined with another division | segmentation core in the root position of an arm part. Therefore, in the state where the stator is divided into the split cores, it is possible to reduce as many members as possible when the coil portion is attached to the magnetic pole portion, and it is possible to attach a larger coil portion to the magnetic pole portion. Moreover, since the location where one divided core and another divided core are joined is the base, the area of the joined location can be increased. As a result, an increase in magnetic resistance due to the split core can be suppressed, and a high output motor can be provided.

  The mounting surface preferably includes a first mounting surface that extends from the end edge in a cross section orthogonal to the rotation axis and is configured in an arc shape along the outer periphery of the rotor.

  According to such a configuration, when the coil portion is mounted on the magnetic pole portion, the coil portion can be temporarily released on the first mounting surface. Therefore, even when a large coil portion is attached to the magnetic pole portion, the coil portion is not caught by the magnetic pole portion, and can be suitably attached.

  Moreover, it is preferable that this mounting surface is provided with the 2nd mounting surface extended toward the outer periphery of this frame from the opposite edge position of this 1st mounting surface in the cross section orthogonal to this rotating shaft.

  According to such a configuration, the position of the other divided core with respect to the one divided core can be defined by the first mounting surface and the second mounting surface intersecting the first mounting surface. Since position control can be performed on two intersecting surfaces, the position of another divided core with respect to one divided core can be accurately defined.

  Further, it is preferable that a fitting portion is provided on the second mounting surface, and a fitting portion that is fitted to the fitting portion is provided on the other yoke portion.

  According to such a configuration, it is possible to make it difficult to come off when another divided core is attached to one divided core. Therefore, at the time of manufacturing the electric power tool, it is possible to maintain a state in which another divided core is mounted on one divided core without using any other jig, and productivity can be increased.

  Further, it is preferable that one of the divided cores and the other divided cores are connected to the bonded portion by bonding the other bonded portion.

  According to such a configuration, one divided core and another divided core can be easily joined.

  Moreover, it is preferable that the coil portion is formed by winding a self-bonding wire.

  According to such a configuration, it is difficult for the coil portion to collapse, and it is difficult for the characteristics to change after the coil portion is mounted on the stator. Therefore, stable performance can be obtained.

  Further, the frame body is constituted by two divisions of a first divided core constituted by the first electrode portion and the first yoke portion and a second divided core constituted by the second electrode portion and the second yoke portion. Preferably it is.

  According to the electric tool of the present invention, a coil bundle as large as possible can be mounted on a small stator core with a reduced number of divisions.

  Hereinafter, a power tool according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9. A disc grinder 1 that is an electric tool shown in FIG. 1 mainly includes a housing 2, a motor 3, a gear mechanism 6, and a grindstone 7 that is a tip tool.

  The housing 2 accommodates the motor 3 therein, and has a tail cover 21 that accommodates a power switch (not shown) that supplies power to the motor 3 at the rear end. A gear cover 22 incorporating the gear mechanism 6 is provided at the tip. The tail cover 21 is formed with an air suction hole 21a for taking in the outside air into the housing 2, and the gear cover 22 is formed with an air discharge hole 22a for discharging the air inside the housing 2 into the outside air. The motor 3 is mainly composed of a stator 3A and a rotor 3B, and an output shaft 31 is provided at a tip portion of the rotor 3B. A fan 32 is provided at the root portion of the output shaft 31, and the fan 32 rotates as the output shaft 31 rotates to generate an air flow from the air suction hole 21 a to the air discharge hole 22 a in the housing 2. The motor 3 is cooled.

  The gear mechanism 6 mainly includes a first bevel gear 61, a second bevel gear 62, and a rotating shaft 63, and is accommodated in the gear cover 22. The first bevel gear 61 is provided on the output shaft 31, and the second bevel gear 62 is disposed so that the rotation shaft is orthogonal to the output shaft 31 and meshes with the first bevel gear 61. The rotating shaft 63 is fixed to the second bevel gear 62 so as to be coaxially rotatable, is supported by the gear cover 22 via a bearing, and functions as a rotating shaft of the second bevel gear 62.

  The grindstone 7 is fixed to the tip of the rotary shaft 63 and is configured to be rotatable coaxially with the rotary shaft 63. A cover 7 </ b> A that is fixed to the gear cover 22 and protects the grindstone 7 is provided around the grindstone 7. Since the grindstone 7 is fixed to the rotary shaft 63 so as to be coaxially rotatable, the grindstone 7 is rotated by the rotation of the output shaft 31 of the motor 3 so that the workpiece can be cut and polished.

  Next, a detailed description of the motor 3 will be described. The motor 3 is a two-pole commutator motor having two magnetic poles, and the stator 3A and the rotor 3B constituting the motor 3 are, as shown in FIG. 2, the rotor 3B in the internal space of the stator 3A. Takes the form of being housed. The stator 3A is composed of a metal material as a base material, and is formed by winding the first and second stator cores 4 and 4 having symmetrical shapes divided into halves, and conducting wires wound around the stator cores 4. The first stator coil bundle 3C and the second stator coil bundle 3C are held in the housing 2 (FIG. 1) by a yoke 41 (to be described later) serving as an outer peripheral portion. The first and second stator cores 4 and 4 are combined to form a frame constituting the stator 3A, and a through-hole penetrating in a direction perpendicular to the circumferential direction of the frame is formed.

  The rotor 3B is configured in a columnar shape, and an output shaft 31 serving as a rotation shaft is disposed in a shaft portion of the column. Yes. Therefore, the circumferential direction of rotation of the rotor 3B and the circumferential direction of the frame of the stator 3A are substantially the same direction.

  Since the first and second stator cores 4 and 4 are both symmetrical, the first stator core 4 will be mainly described. As shown in FIG. 3, the first stator core 4 includes a yoke part 41 located on one end side in the frame body circumferential direction and a magnetic pole part 42 located on the other end side in the frame body circumferential direction and integral with the yoke part 41. It is configured. The yoke portion 41 is formed in a substantially arc shape, and has a joint portion 41A that joins the second stator core 4 that is another divided core at one end position in the frame body circumferential direction. The joining portion 41A is formed in an arc shape along the outer periphery of the rotor 3B, and an adhesive surface 41B that is bonded to a first mounting surface 43A (FIG. 9) described later, and a convex portion that protrudes in the circumferential direction of the frame body And a convex portion 41 </ b> C that fits into a second mounting surface 43 </ b> B (FIG. 9) described later of the second stator core 4.

  The magnetic pole part 42 has a joined part 43 to which the joined part 41A of the second stator core 4 is joined, and is adjacent to the base part 42A to which the yoke part 41 is connected, and the rotor 3B (FIG. 2) and the base part 42A. The magnetic pole 44 is provided with a first arm portion 44A and a second arm portion 44B that are spread out from and extended to one side and the other side of the rotor 3B in the circumferential direction along the surface of the rotor 3B.

  The joined portion 43 includes a first mounting surface 43A and a second mounting surface 43B. 43 A of 1st mounting surfaces are comprised by the circular arc shape along the outer periphery of the rotor 3B (FIG. 2) by making the base end part of the 2nd arm part 44B into the other end of the circumferential direction. The second mounting surface 43B is configured to extend in a direction from one circumferential position of the first mounting surface 43A toward the outer periphery of the frame body. The second mounting surface 43B is formed with a recess that is recessed toward one end in the circumferential direction and that can be fitted to the protrusion 41C of the second stator core 4.

  A first slot 44a is formed by the first arm portion 44A located on one side in the circumferential direction of the rotor 3B and the yoke portion 41 integral with the base portion 42A. A second slot 44b is formed by the second arm portion 44B on the other circumferential side of the rotor 3B and the yoke portion 41 of the second stator core 4 joined to the base portion 42A (FIG. 2). The first stator coil bundle 3C is mounted across the 44a and the second slot 44b.

  The first stator coil bundle 3C is wound with a self-bonding wire that is hardened by heating, and as shown in FIGS. It is wound. Since the first stator coil bundle 3C is simple to wind, it is possible to form clean aligned windings and reduce errors between products. The first insulating paper 3D and the second insulating paper 3E are wound around the two sides which are the long side portions of the first stator coil bundle 3C. In the first stator coil bundle 3C, a portion where the first insulating paper 3D is wound and a portion where the second insulating paper 3E is wound are respectively attached to the first slot 44a and the second slot 44b. Become. Hereinafter, portions where the first insulating paper 3D and the second insulating paper 3E of the first stator coil bundle 3C are wound will be abbreviated as the first insulating paper 3D and the second insulating paper 3E.

  As shown in FIGS. 5A and 5B, the first stator coil bundle 3C is easily connected to the first slot 44a and the second slot 44b (FIG. 3). The second slot 44b is bent along the curved shape of each yoke portion 41 that defines the second slot 44b. In this state, the distance L1 from the first insulating paper 3D to the second insulating paper 3E in the opening 3c of the first stator coil bundle 3C is set to the second position from the base position of the first arm portion 44A in the magnetic pole portion 42 in FIG. It is configured to be slightly larger than the distance L2 to the base position of the arm portion 44B and larger than the distance L3 from the second mounting surface 43B to the tip position of the first arm portion 44A. Since the stator coil bundle 3C is bent and shaped and heated, the stator coil bundle 3C is fixed in a curved state. By being fixed in this state, when the stator coil bundle 3C is attached to the first stator core 4, it is difficult to cause winding collapse or the like, and the stator coil bundle 3C can be suitably attached. Moreover, since the shape is fixed when the motor 3 is disassembled by recycling or the like, the stator coil bundle 3C can be easily removed.

  In order to mount the first stator coil bundle 3C having the above configuration on the first stator core 4, as shown in FIG. 6, first, the second arm portion 44B is passed through the opening 3c, and thereafter, as shown in FIG. As shown, the second insulating paper 3E is moved to the position near the second mounting surface 43B in a state along the first mounting surface 43A.

  As described above, since the width L1 of the opening 3c is larger than the distance L3 from the second mounting surface 43B to the tip position of the first arm portion 44A, the second insulating paper 3E is formed on the second mounting surface 43B. By moving to the vicinity, the first insulating paper 3D contacts the inner surface of the first yoke portion 41 beyond the tip position of the first arm portion 44A. Further, since the first mounting surface 43A extends to the second mounting surface 43A with the root position of the second arm portion 44B as the other end in the circumferential direction, the first mounting surface 43A extends from the second arm portion 44B through which the second insulating paper 3E passes. There is no protruding portion between the second mounting surface 43B across the one mounting surface 43A. Therefore, there is no member that obstructs the operation of the second insulating paper 3E within the range in which the second insulating paper 3E moves when the first stator coil bundle 3C is attached to the magnetic pole portion 42, and the second insulating paper 3E can be freely operated. The degree can be increased, and the first stator coil bundle 3 </ b> C can be attached to the magnetic pole part 42 more preferably.

  From this state, the first stator coil bundle 3C is rotated clockwise with respect to the first stator core 4 so that the first insulating paper 3D is inserted into the first slot 44a. By this rotation, as shown in FIG. 8, the first insulating paper 3D is arranged in the first slot 44a, and the second insulating paper 3E moves on the first mounting surface 43A, and on the second arm portion 44B. Located in.

  Since the distance L1 between the first insulating paper 3D and the second insulating paper 3E is slightly larger than the distance L2 from the base position of the first arm portion 44A to the base position of the second arm portion 44B, as described above. By rotating the first stator coil bundle 3C, the second insulating paper 3E is not placed on the first mounting surface 43A.

  In the state where the first insulating paper 3D portion of the first stator coil bundle 3C is disposed in the first slot 44a, the second stator coil bundle is similarly applied to the first stator core 4 as shown in FIG. The 2nd stator core 4 with which 3C was mounted | worn is combined. At this time, the first mounting surface 43A of each of the first and second stator cores 4 is assembled in a state in which the respective adhesive surfaces 41B of the first and second stator cores 4 coated with the adhesive are aligned. The convex portions 41C of the first and second stator cores 4 are fitted to the second mounting surfaces 43B of the first and second stator cores 4, respectively. By joining the first stator core 4 and the second stator core 4 in this way, the position of the second stator core 4 with respect to the first stator core 4 is changed to the first mounting surface 43A and the first mounting surface 43A. The second mounting surface 43B intersecting with Since position regulation can be performed on two intersecting surfaces, the position of the second stator core 4 with respect to the first stator core 4 can be accurately defined.

  The second mounting surface 43B is provided with a concave portion, and the convex portion 41C is fitted into the concave portion. Therefore, after the second stator core 4 is mounted on the first stator core 4, the first stator core 4 The second stator core 4 is difficult to come off. Therefore, while the adhesive applied to the bonding surfaces 41B of the first and second stator cores 4 is cured and the first stator core 4 and the second stator core 4 are bonded together, Even if it does not use etc., dissociation of the 1st fixed core 4 and the 2nd stator core 4 is suppressed.

  After the second stator core 4 is joined to the first stator core 4 and the adhesive is cured, the rotor 3B and the like shown in FIG. 2 are mounted, and the motor 3 is completed.

  According to the motor 3 having the above configuration, for example, the first stator core 4 is composed of one yoke portion 41 and one magnetic pole portion 42, and therefore only one yoke portion 41 extends from the magnetic pole portion 42. It is. Generally, when the stator coil bundle is attached to the magnetic pole part, the yoke part becomes an obstacle. However, if the structure includes only one yoke part as in this case, the stator coil bundle 3 can be easily attached. it can.

  Further, the first stator coil bundle 3C is bent along the inner peripheral shape of the yoke portion 41, and then the second arm portion 44B and the first arm portion 44A are opened by taking the dimensional relationship of L1 to L3. It can penetrate the hole 3c. By being able to pass through, the first insulating paper 3D moves along the inner circumference of the first yoke portion 41, and then the first stator coil bundle 3C is rotated to move the first insulating paper 3D into the first slot 44a. The first stator coil bundle 3 </ b> C can be attached to the magnetic pole part 42. That is, if the first insulating paper 3D has the opening 3c that can get over the second arm 44B and the first arm 44A and contact the inner periphery of the first yoke 41, the first stator coil bundle 3C It can be attached to the magnetic pole part 42. Therefore, as shown in FIG. 2, in the state where the motor 3 is configured, the large first and second stator coil bundles 3C and 3C that substantially fill the gap between the stator 3A and the rotor 3B are provided. Therefore, the largest stator coil bundle can be mounted in a small slot of a small stator core. In addition, since the gap is filled, the air layer serving as a heat insulating material is reduced, and the heat generated by the first stator coil bundle 3C can be more suitably transferred to the first and second stator cores 4 and 4. As a result, the cooling performance of the motor 3 is enhanced, and the performance degradation of the motor 3 can be suppressed.

  The locations where the first stator core 4 and the second stator core 4 are joined become the first mounting surface 43A and the second mounting surface 43B of the base 42, and the area of the joining location is large. As a result, an increase in magnetic resistance due to the stator 3A being composed of the split cores can be suppressed, and the motor 3 can have high output. Further, since the yoke portion 41 and the magnetic pole portion 42 are integrated in one stator core 4, it is necessary to match the yoke portion 41 and the magnetic pole portion 42 when the stator core 4 is mounted on the housing 2. Therefore, the positional accuracy of the magnetic pole 44 can be easily increased.

  The power tool according to the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made within the scope described in the claims. For example, in the present embodiment, a two-pole motor has been described. However, the present invention is not limited to this, and by using three or more stator cores composed of one magnetic pole part and one yoke part, The present invention can also be applied.

  Further, one stator core and another stator core are bonded by an adhesive, but the present invention is not limited to this, and may be bonded by welding or the like. In addition, an insulating coating may be applied to the surface of the stator core.

  The electric power tool of the present invention is not limited to the disk grinder described in the embodiment, and needless to say, the present invention can be applied to any electric power tool including a motor.

1 is a cross-sectional view of a disc grinder according to an embodiment of the present invention. Sectional drawing of the motor of the disk grinder concerning embodiment of this invention. Sectional drawing which shows the frame which comprises the stator of the motor of the disk grinder concerning embodiment of this invention. FIG. 4A is a plan view of a stator coil bundle of the motor of the disc grinder according to the embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along line IV-IV. (A) Top view in the state where the stator coil bundle of the motor of the disc grinder motor concerning an embodiment of the invention was curved, and (b) Sectional drawing along a VV line. Sectional drawing which shows the state which attaches 3 C of stator coil bundles to the 1st stator core of the motor of the disk grinder concerning embodiment of this invention (The state which made the 2nd arm part pass through the hole of a stator coil bundle) . Sectional drawing which shows the state which attaches 3 C of stator coil bundles to the 1st stator core of the motor of the disc grinder concerning Embodiment of this invention (The state which made the stator coil bundle contact | abut to a 1st yoke part). Sectional drawing which shows the state which mounts 3 C of stator coil bundles to the 1st stator core of the motor of the disc grinder concerning embodiment of this invention (rotating a stator coil bundle with respect to the 1st stator core 4) State). Sectional drawing which shows the state which combines the 1st stator core and 2nd stator core of the motor of the disc grinder concerning embodiment of this invention.

Explanation of symbols

1. Disc grinder 2. Housing 3. Motor 3A Stator 3B Rotor 3C First and second stator coil bundle 3D First insulation paper 3E Second insulation paper 3c・ ・ Open holes 4 ・ ・ First and second stator cores 6 ・ ・ Gear mechanism 7 ・ ・ Whetstone 21 ・ ・ Tail cover 21a ・ ・ Air intake hole 22 ・ ・ Gear cover 22a ・ ・ Air discharge hole 31 ・ ・ Output shaft 32 .. Fan 41... First and second yoke portion 41 A... Bonding portion 41 B... Adhesive surface 41 C .. Convex portion 42... Magnetic pole portion 42 A. Surface 43B, second mounting surface 44, magnetic pole 44A, first arm 44B, second arm 44B, second arm 44a, first slot 44b, second slot 61, first Bevel gear 62 ・ ・ Second bevel gear 63 ・ ・ Rotating shaft 7A ・ ・Bar

Claims (4)

A housing;
A motor disposed in the housing and driving a tip tool,
The motor includes a stator configured by combining a plurality of divided cores having slots, a plurality of coil portions attached to the stator, and a rotor disposed rotatably in the stator. Configured
Each of the plurality of coil portions has a winding wound before being attached to the stator,
Each of the plurality of divided cores includes a yoke portion located on one end side in the circumferential direction of the stator and a magnetic pole portion located on the other end side and integral with the yoke portion, and extends from the magnetic pole portion. A pair of arms extending respectively on one side and the other side in the circumferential direction of the rotor;
An arcuate mounting surface provided on the outer peripheral side of the arm part on the yoke side,
The slot is formed in a space surrounded by the arm part on the yoke side and the yoke part,
In the state where the divided core is divided, the coil unit is configured to move along the mounting surface and be accommodated in the slot. The mounting surface is a first mounting surface that extends from a base end portion of the arm portion in a cross section orthogonal to the rotation axis of the motor and is configured in an arc shape along the outer periphery of the rotor ;
Electric tool according to claim 1, characterized in that it comprises a second mounting surface which is extended toward the counter-edge position of the first mounting surface on the outer periphery of the frame body in a cross section orthogonal to the rotation axis . A fitted portion is provided on the second mounting surface of one divided core, and a fitted portion that is fitted to the fitted portion is provided on the yoke portion of the other divided core. The electric tool according to claim 2 . The yoke portion of the one split core has a joint portion that joins the other split core at one end position in the frame circumferential direction,
The magnetic pole part of the one divided core has a joined part to which the yoke part is connected and the joined part of the other divided core is joined.
The said one split core and the other divided cores 1 through claim, characterized in that the junction of the other divided cores to be joined portion of the divided core the one is connected is adhered The power tool according to claim 3 .

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