JP6542150B2 - Handheld cutting tool - Google Patents

Description

  The present invention relates to, for example, a hand-held cutting tool called a portable circular saw.

This type of cutting tool has a configuration in which a tool main body provided with a circular rotary blade that is rotated by an electric motor is supported on the upper surface of a base placed on a cutting material, and the rotation protruded to the lower surface side of the base The cutting process is performed by moving the tool body in the cutting advancing direction while cutting the lower part of the cutting tool into the cutting material. For this reason, the tool main body is provided with a handle that is gripped by the user in order to move the tool in the cutting direction.
In addition to the loop (endless) type, this handle portion is provided in a bar shape having an end (free end) as disclosed in, for example, the following patent documents. The latter bar-shaped handle has the advantage of having a high degree of freedom in gripping direction (posture) since it does not require an operation such as inserting the hand inside the user like the former loop-shaped handle, and it is easy to grip is there.

JP-A-4-251702

However, in the case of the conventional bar-shaped handle portion, since it has a shape extending straight back from the tool body, there is a problem that it is difficult for the gripped user to apply a force in the cutting advancing direction. For this reason, the conventional user must move the cutting tool while holding the hand in a somewhat cramped posture, and from this point it is necessary to improve the conventional handle portion and thus to improve the operability of the cutting tool. there were.
Therefore, the present invention aims to enhance the usability of the conventional bar-shaped handle portion, thereby further enhancing the operability of the cutting tool.

For this reason, the present invention is a cutting tool configured as described in each claim.
The cutting tool according to claim 1 comprises a base brought into contact with the upper surface of a cutting material, and a tool body supported on the upper surface of the base, the tool body being a circular rotary blade that rotates with an electric motor as a drive source. A cutting tool for holding the handle portion and rotating the rotary blade while moving the cutting tool in the cutting advancing direction to cut the cutting material, wherein the handle portion is a cutting tool. , for the previous SL motor shaft position of the electric motor intersecting the cutting direction, it is disposed on said blade case side portion position of the electric motor side and the electric motor of the blade case for accommodating the rotary blade and extends from the front portion to the cutting direction rearward located within a range between the position of the anti-electric motor side cooling fan, and the handle portion, the cutting depth of the rotary blade is most Curved chevron that is convex upward in side view, part for a user to grip are arranged on the rear side than the rear edge of the blade case in side view, the rotation control of the electric motor at the time of the controller for, disposed below the upper side and the front portion of the handle portion of the blade case, the controller for the position of the motor shaft line direction between the cooling fan and the rotary blade The cutting tool is provided so as to overlap the pinion gear attached to the output shaft of the electric motor in the axial direction of the motor.
The cutting tool according to claim 2 is the cutting tool according to claim 1, wherein the top of the handle portion is behind the rotation center of the rotary blade and behind the motor axis of the electric motor. It is a configuration that has been positioned.
A cutting tool according to a third aspect of the present invention is the cutting tool according to the first or second aspect, wherein a switch lever for start operation operated by a user is provided on the lower surface of the handle portion, and the switch lever Is positioned forward of the rear end edge of the base in the cutting direction.
The cutting tool according to claim 4 is the cutting tool according to any one of claims 1 to 3, comprising a two-stage reduction gear train between the electric motor and a spindle on which the rotary blade is mounted. Configuration.
A cutting tool according to a fifth aspect is the cutting tool according to any one of the first to fourth aspects, further comprising a blower for blowing off the cutting powder at the cutting site.

It is a right side view of a cutting tool concerning an embodiment of the present invention. It is the perspective view which looked the cutting tool of this embodiment from diagonally right side back. It is the perspective view which looked at the cutting tool of this embodiment from diagonally left front. It is the side view which looked at the cutting tool of this embodiment from the left side. It is a (V)-(V) line arrow view of FIG. 1, and is a cross-sectional view of a handle part. FIG. 6 is a view taken along line (VI)-(VI) of FIG. 1 and is a cross-sectional view of the handle portion. FIG. 7 is a view taken along line (VII)-(VII) of FIG. 1 and is a cross-sectional view of the battery pack. It is the side view which looked at the cutting tool from the left side. In the drawing, the tool body is moved upward to minimize the cutting depth of the rotary blade. It is the perspective view which looked the cutting tool from the back slanting upper part. This figure shows a state where the cutting depth of the rotary blade is minimized as in FIG. It is a top view of a cutting tool. It is a bottom view of a cutting tool. It is the perspective view which looked at the cutting tool diagonally from the left front. This figure is different from the state shown in FIG. 3 in that the dust collection duct is attached. It is the perspective view which looked at the cutting tool diagonally from the left front. In the figure, the front half housing of the motor housing and the blower duct are shown removed. It is a cross-sectional view of a blower duct and an outlet. It is an (XV)-(XV) line arrow view of FIG. This figure is the upper part of a blade case, Comprising: The longitudinal cross-sectional view of an electrical component storage chamber and its periphery is shown. It is a disassembled perspective view of a motor lock lever, a compression spring, and a spring storage chamber. It is a right view of a cutting tool. In the figure, the handle portion is shown in longitudinal section. It is a perspective view inside blade case. In the figure, the rotary blade is shown in a removed state. FIG. 19 is a view taken along line (XIX)-(XIX) in FIG. 18 and a plan view of the rear hooking portion of the tension spring. It is the side view which looked at the cutting tool from the left side. In the figure, the right hand grips the handle portion, and the left hand grips the motor housing as a subgrip.

Next, an embodiment of the present invention will be described based on FIGS. 1 to 4 show the entire hand-held cutting tool 1 according to the present embodiment. The cutting tool 1 is a relatively small and lightweight cutting machine called a portable circular saw, which can be cut by the user holding the hand and moving it on the cutting material W. First, the entire configuration will be roughly described.
The cutting tool 1 has a configuration in which a tool body 10 is supported on the upper surface of a flat base 2 that is placed on the upper surface of a cutting material W. In FIG. 1, the user is located on the left side of the cutting tool 1. The cutting process proceeds by moving the cutting tool 1 in FIG. 1 to the right (in the direction indicated by the white arrow (A) in FIG. 1). In the following description, the direction in which the cutting process proceeds is the front side, and the front side is the rear side as viewed from the user, unless otherwise specified. Moreover, unless otherwise indicated, the user is taken as a standard about the horizontal direction of a member and composition.
The tool main body 10 is coupled to the bracket 2a attached to the upper surface of the base 2 via the support shaft 3 so as to be vertically tiltable and supported by the upper surface of the base 2 via the support shaft 11 ing. The cutting depth of the rotary blade 12 with respect to the cutting material W can be adjusted by changing the vertical tilt position of the tool body 10 with respect to the base 2 through the support shaft 3. The vertically inclined position of the tool body 10 with respect to the base 2 is fixed by tightening a thumb screw 4 provided at the rear end. The tool body 10 is also supported so as to be tiltable to the left and right with respect to the base 2. A so-called bevel cutting can be performed by tilting the tool body 10 to the left or right.

As shown in FIGS. 9 and 11, the base 2 is provided with a substantially rectangular window portion 2b long in the front and back direction. The window portion 2 b is provided to penetrate in the thickness direction of the base 2. The lower side of the rotary blade 12 is protruded to the lower surface side of the base 2 through the window portion 2 b. The portion of the rotary cutting tool 12 which is protruded to the lower surface side of the base 2 is cut into the cutting material W to be cut. Therefore, among the intersections between the lower surface of the base 2 and the cutting edge of the rotary blade 12, the intersection on the front side in the cutting advancing direction is the part actually cut into the cutting material W, and cutting powder is generated at this part. Hereinafter, this site is referred to as a cleavage site, and the code C is used as illustrated.
The tool body 10 is provided with a circular rotary blade 12 that rotates using the electric motor 40 as a drive source. The upper portion of the rotary blade 12 is accommodated in the blade case 13. The blade case 13 includes a case cover 13a that covers the upper right side of the rotary blade 12 and a case main body 13b that covers the upper left side of the rotary blade 12 coupled to each other. As shown in FIG. 3, the electric motor 40 is attached to the left side (rear side) of the case body 13 b of the blade case 13 via the gear head portion 14. In the gear head housing 14 d of the gear head portion 14, a gear train for reduction is installed.
As shown in FIG. 15, the rotational output of the electric motor 40 is transmitted to the spindle 17 through the gear head portion 14. The spindle 17 is rotatably supported on the inner peripheral side of a boss portion 28 provided on the case main body 13 b of the blade case 13 via a bearing 29. The rotary blade 12 is coaxially attached to the tip of the spindle 17. The rotary blade 12 is fixed to the tip of the spindle 17 in a state of being sandwiched between the receiving flange 18 and the fixing flange 19. The pinched state of the receiving flange 18 and the fixing flange 19 is fixed by tightening the fixing screw 27 on the tip of the spindle 17. Therefore, the rotary blade 12 can be removed from the spindle 17 by loosening the fixing screw 27 and removing it from the tip of the spindle 17.

The handle portion 20 is provided on the upper portion of the case body 13b of the blade case 13 so as to largely extend rearward. The handle portion 20 has a left and right half structure. On the front lower surface of the handle portion 20, a switch lever 21 for start operation is provided. As shown in FIG. 17, the switch lever 21 is supported so as to be capable of tilting operation up and down via a support shaft 21b. A switch body 26 is internally provided on the upper side of the switch lever 21. When the switch body 26 is turned on, the electric motor 40 is started.
When the user holds the finger tip of the hand holding the handle portion 20 (forefinger F2) on the finger rest portion 21a of the switch lever 21 and pulls it upward, the switch body 26 is turned on and the electric motor 40 is activated. When the electric motor 40 is activated, the rotary blade 12 rotates in the direction of the white arrow (B) in the figure. When the finger is released and the pulling operation of the switch lever 21 is stopped, the switch main body 26 is turned off and the electric motor 40 is stopped, so that the rotary blade 12 is stopped.
A lock off lever 23 is provided on the upper side of the switch lever 21. The switch lever 21 can be pulled only when the lock off lever 23 is pressed downward.
The cutting tool 1 according to the present embodiment has a major feature (first feature) mainly in the outer shape of the handle portion 20. The electric motor 40 has the second feature mainly in the outer shape. The details of the first and second features will be described later.
A battery pack 22 is attached to the rear end of the handle portion 20. When the battery pack 22 is inserted into the rear end of the handle portion 20 as shown in FIG. 17, the power supply circuit side of the electric motor 40 is supplied with power. The battery pack 22 can be repeatedly used by charging it with a charger prepared separately and prepared separately.

The cutting process proceeds by cutting the rotary blade 12 rotated by the electric motor 40 into the cutting material W. The rotary blade 12 rotates in the direction indicated by the white arrow (B) in FIG. 1 (counterclockwise in FIG. 1). For this reason, when the cutting process is performed, the cutting powder is blown up from the cutting portion (cutting portion C) to the cutting material W of the rotary blade 12. Part of the blown-up cutting powder flows backward in the blade case 13, and the remaining dust is deposited near the cutting site C of the cutting material W. The cutting tool 1 of the present embodiment includes a blower 30 for blowing off the cutting powder in the vicinity of the cutting site C. Cooling air of the electric motor 40 is used for the blower 30. The cutting tool 1 of the present embodiment has a third feature in that it includes a blower 30 that blows off the cutting powder using this motor cooling air. Further, the cooling air of the electric motor 40 is also used to cool the built-in electric component, and has the fourth feature in this respect. The third and fourth features will also be described later.
Furthermore, as shown in FIGS. 2, 9 and 11, the cutting tool 1 of the present embodiment has a large feature (fifth feature) as to the shape of the rear end portion of the base 2 described above.
Further, as described above, the upper side of the rotary blade 12 is covered by the blade case 13 described above. The lower side periphery of the rotary blade 12 is covered with a movable cover 16. The movable cover 16 is supported on the tool body 10 side. The movable cover 16 is rotatably supported around an axis of a spindle 17 to which the rotary blade 12 is attached. The movable cover 16 has its front end abutted against the cutting material W, and in this abutted state, the cutting tool 1 is relatively pushed rearward by movement in the cutting advancing direction to be opened. As shown in FIG. 18, the movable cover 16 is spring biased in a closing direction covering the periphery of the rotary blade 12. The cutting tool 1 of the present embodiment has the sixth feature as to the mounting form of the tension spring 45 for biasing the movable cover 16 in the closing direction.
As briefly described above, the cutting tool 1 of the present embodiment has the first to sixth features not found in the prior art. The first to sixth features will be described in order below.

[First feature: Outline of the handle portion 20]
As shown in the figure, the cutting tool 1 has a rod shape extending in parallel to the surface direction of the rotary blade 12 with the tool main body 10 side (gear head portion 14 side) as a base end (the rear side is an end and in the loop shape (Not shaped) handle portion 20 is provided. As shown in FIG. 1, the handle portion 20 has an arch shape (arc shape) gently curved in a chevron shape ("H" shape) that is generally upwardly convex in a side view. For this reason, in the state where the tool body 10 is positioned at the lowermost side and the cutting depth of the rotary blade 12 is maximized, the handle 20 has the highest portion in a side view. Hereinafter, this portion is referred to as the top H. The topmost portion H is set at a position near the base end. The curvature of the top H is set the largest, and the top H is tightly curved. In the present embodiment, the curvature of the front side region R1 closer to the base end than the top H, which is dimensioned with a radius of 100 mm, is such that the upper surface is gently curved with a curvature smaller than the top H. The curvature of the region R2 behind the top H is smaller at a curvature smaller than that of the front region R1, and the upper surface is gently curved so as to be most compatible with the user's palm. In this embodiment, dimensions are set at a radius of 400 mm. Thus, the region R2 on the rear side from the top H is most gently curved and inclined in the downward direction. The switch lever 21 is disposed on the lower surface side near the topmost portion H.
As described above, since the handle portion 20 has a rod shape (not loop shape) whose rear end is an end, it is easier to insert and hold a finger than a loop shape handle. Moreover, since the area R2 behind the top H of the handle portion 20 and the area to which the palm is put is inclined downward, the cutting tool 1 is moved forward as compared to the case where it extends horizontally. The pressing force can be efficiently introduced in a comfortable posture, and at this point, high handleability of the handle portion 20 is ensured.
Further, regarding the positional relationship in the front-rear direction, the topmost portion H of the handle portion 20 is behind the rotation center (spindle 17) of the rotary blade 12 and the motor shaft of the electric motor 40 (axis of output shaft 41, see FIG. 14). It is located behind the). For this reason, the center of gravity of the tool body 10 is positioned on the front side of the topmost portion H of the handle portion 20, and as a result, the cutting tool 1 can be easily pushed to the front side by the hand holding the handle portion 20.
Furthermore, regarding the positional relationship in the vertical direction, the rear end side of the handle portion 20 is located below the upper end (the height indicated by reference numeral 12 h in FIG. 1) of the rotary blade 12.

Next, as shown in FIGS. 10 and 11, the handle portion 20 has a narrow front side (small width) and a wide rear side (large width) mainly in its width dimension. In the present embodiment, with the rear portion of the switch lever 21 as a boundary, the front region R3 indicated by the region R3 in FIGS. 10 and 11 is, for example, a region to which mainly the thumb F1 and the forefinger F2 of the griped right hand RH are applied. Yes, the width dimension D3 is set small. On the other hand, the rear region R4 indicated by the region R4 in FIGS. 10 and 11 is a region to which mainly the middle finger F3, the ring finger F4, the little finger F5 and the palm FP of the gripped hand are applied, and the width dimension D4 is from the front Is also larger (D3 <D4). As a result, pullability of the switch lever 21 by the index finger F2 can be easily performed, and the thick region on the rear side can be held between the middle finger F3, the ring finger F4, the little finger F5, and the palm FP reliably. It has become.
As described above, the handle portion 20 has a curved shape on the upper side in a side view, and the width dimension also is formed to be thick on the rear side, so that high operability of the cutting tool 1 can be obtained, and used It is designed to give the wearer a very good grip.
The battery pack 22 attached to the rear end of the handle portion 20 is also devised. As shown in FIG. 6, this battery pack 22 has three cells 22a to 22a installed therein. In the present embodiment, a relatively small battery pack 22 having a voltage of 10.8 V to 12 V is used. As shown in FIG. 6, two cells 22a to 22a are arranged in parallel on the upper side and arranged in an inverted triangle in which one cell is arranged on the lower side. For this reason, the battery pack 22 is mounted in a pointed direction with the top of the triangle positioned downward. The rear end shape of the handle portion 20 is set in accordance with an inverted triangle in which the top of the battery pack 22 is positioned downward.
The cross-sectional shape in the vicinity of the rear end of the handle portion 20 is formed in a downward triangle with the top facing downward and the bottom side on the top surface. For this reason, the cross-section on the rear side of the handle portion 20 has a triangle with the smallest number of angles among the polygons, so that the angles of the three corner portions become smaller, and as a result, even in the vicinity of the little finger F5 where power is difficult to enter It becomes difficult to slip, and the operability of the cutting tool 1 can be further enhanced. That is, the rear end lower surface of the handle portion 20 to which the ring finger F4 and the little finger F5 are mainly applied has a curved outer shape with a slightly large curvature and corresponding to the top of the inverted triangle. For this reason, it is possible to apply the ring finger F4 and the little finger F5, which are relatively difficult to enter, to be wound around the tightly curved lower surface, whereby a good grip feeling can be obtained and the operating force can be applied more efficiently.
In addition, when the handle 20 has a triangular shape with the cross section downward, it becomes easy to apply a gripping force to the swing around the handle, and it becomes easy to move and operate the cutting tool in a more stable posture.

Further, as shown in the drawing, when the battery pack 22 is attached, the rear end of the handle 20 reaches the battery pack 22 so that the outer surfaces (particularly the upper surfaces) of the two are flush with each other. The outer shape of the end and the outer shape of the battery pack 22 are set. The battery pack 22 is mounted on the rear end of the handle portion 20 so that the battery pack 22 does not extend largely to the side, and the battery pack 22 is integrated with the handle portion 20 to improve appearance. Together with the work.
The battery pack 22 is inserted and mounted in a housing provided at the rear end of the handle portion 20. The mounting state of the battery pack 22 is held by engaging the engagement claws provided on the left and right sides thereof with the accommodation portion. Removal buttons 22 b of the battery pack 22 are provided. When the removal buttons 22b, 22b are pressed, the engagement state of the claws is released, and the battery pack 22 can be removed from the storage portion. The removed battery pack 22 can be repeatedly used by charging it with a charger.
The surface of the handle portion 20 is coated with an elastomeric resin layer 24 mainly for anti-slip. The elastomer resin layer 24 is integrally formed on the surface of the handle portion 20 by a two-color molding method in the manufacturing process of the handle portion 20. The elastomeric resin layer 24 is coated on the upper surface of the area from the vicinity of the top H of the handle portion 22 to the front side (the area on the front side of the lock-off lever 23). The thumb F 1 is mainly applied to the upper surface covering portion 24 a of the elastomeric resin layer 24. The elastomeric resin layer 24 is coated in a region extending substantially around the entire circumference of the region from the vicinity of the top H of the handle portion 20 to the rear side (region behind the lock-off lever 23). As shown in FIG. 20, the middle finger F3, the ring finger F4, the little finger F5, and the palm FP are mainly applied to the entire circumference covering portion 24b of the elastomer resin layer 24.
As described above, by covering the elastomeric resin layer 24 in a range to which the user's fingers F1 to F5 and the palm FP of the user are applied, the handle portion 20 can have high anti-slip function and good grip feeling. Together with the above-described curved shape that bulges upward, the handle portion 20 can have good operability and a good grip.
In FIG. 1 and FIG. 4, the hatching of a lattice pattern is given to the range which covered the elastomer resin layer 24 (24a, 24b) of the handle part 20, and the said range is shown clearly.
On the rear end lower surface of the handle portion 20, a leg portion 25 protruding downward is integrally provided. When the cutting tool 1 is placed on, for example, a workbench, the leg portion 25 has a function of grounding the workbench and preventing the cutting tool 1 from falling sideways and holding the cutting tool 1 in a self-standing posture. The surface of the legs 25 is also coated with an elastomeric resin layer to prevent damage to the work table and the cutting material W. When the battery pack 22 is removed, this leg 25 protrudes, which is particularly effective. The leg 25 also has a function as a screw connection portion of the handle portion 20 having a half split structure.

[Second feature: Outline of motor 40]
As shown in FIGS. 3 and 4, the electric motor 40 is fixed to the gear head portion 14 by three fixing screws 42 to 42. The electric motor 40 is attached so as to protrude leftward from the gear head portion 14. The output shaft 41 of the electric motor 40 is disposed parallel to the spindle 17 with its axis in the left-right direction. As shown in FIG. 15, the gear head portion 14 is internally provided with a plurality of (two in this example) reduction gear trains. The two-stage reduction gear train is interposed between the output shaft 41 and the spindle 17. A pinion gear 41 a is attached to the output shaft 41 of the electric motor 40. The pinion gear 41a is engaged with the intermediate drive gear 14a. The intermediate drive gear 14a is fixed on the intermediate shaft 14b. The intermediate drive gear 14a and the intermediate driven gear 14c are fixed on the intermediate shaft 14b. Therefore, the intermediate drive gear 14a and the intermediate driven gear 14c rotate integrally. The intermediate driven gear 14 c is engaged with an output gear 17 a fixed to the spindle 17. Therefore, the output of the electric motor 40 is decelerated in two steps through the meshing of the pinion gear 41a and the intermediate drive gear 14a, the meshing of the intermediate driven gear 14c and the output gear 17a, and transmitted to the spindle 17. Further, an intermediate shaft 14 b is disposed above the spindle 17, and an output shaft 41 is disposed above and behind the intermediate shaft 14 b. For this reason, a large interaxial distance is set between the output shaft 41 of the electric motor 40 and the spindle 17, and the electric motor 40 is disposed above the spindle 17 by an appropriate distance.
As described above, the rotational output of the electric motor 41 is transmitted to the spindle 17 via the two-step reduction gear train, and the electric motor 40 is disposed at a position offset above the spindle 17. An appropriate gap is generated between the base 2 and the electric motor 40 even when the cutting depth of the cutting tool 12 is set. Therefore, when the user grips the electric motor 40 with the left hand LH as a subgrip as described below, the fingertip of the left hand LH does not touch the base 2 or the like. Usability as a grip is secured.

The electric motor 40 is provided with half housings 43 a and 43 b which are divided in half along the output shaft 41. The front and rear half housings 43a and 43b are butted to form a cylindrical motor housing 43.
As shown in FIG. 3, the motor housing 43 has a flat cylindrical body shape (L1> L2) in which the width in the vertical direction (vertical width L1) is large and the width in the front and rear direction (front and rear width L2) is slightly small. The flat cylindrical shape of the motor housing 43 facilitates gripping by the user. The electric motor 40 is protruded to the left as viewed from the user. Therefore, as shown in FIG. 20, the user can hold the handle portion 20 with the right hand RH and hold the electric motor 40 as the subgrip with the left hand LH. In this case, the cutting tool 1 with both hands RH and LH. Can be held, so that stable movement operation can be performed.
Further, regarding the vertical position of the output shaft 41 of the electric motor 40 with respect to the motor housing 43, the output shaft 41 is disposed at a height position where the longitudinal width L2 of the motor housing 43 is maximum, and the vertical direction of the motor housing 43 It is arranged at a position shifted downward from the center. In addition, the upper portion of the motor housing 43 is formed in a round and pointed shape with a cross section having a curvature larger than that of the lower portion. Since the upper portion of the motor housing 43 is formed in a slightly chevron-like shape, when the user grips the motor housing 43 with the left hand LH as a subgrip, the upper portion of the motor housing 43 is a thumb of the left hand LH. A higher grip feeling can be obtained by getting in between F1 and the forefinger F2.
Furthermore, the motor housing 43 has a cylindrical shape whose thickness does not change in the axial direction (left and right direction) of the output shaft 41. The left and right half housings 43a and 43b of the motor housing 43 are individually made of resin. Therefore, in the motor housing 43 of this embodiment, so-called draft (necessary for gradually taking out from the mold which is required in the case of forming a cylindrical shape from the beginning generally in the prior art) It is not necessary to set the motor housing 43. As a result, the motor housing 43 has a uniform shape in the axial direction of the motor, from this point as well, a good grip feeling as the subgrip of the motor housing 43 is obtained. It is supposed to be
Further, as shown in FIG. 4, the electric motor 40 is disposed on the front side of the switch lever 21 of the handle portion 20. For this reason, the right hand RH gripping the handle portion 20 and the left hand LH gripping the electric motor 40 as a subgrip do not interfere with each other. Also in this respect, as the subgrip of the handle portion 20 and the electric motor 40 Good usability of is secured.

[Third feature: dust blower]
As described above, the cutting tool 1 of the present embodiment includes the blower 30 for blowing off the cutting powder in the vicinity of the cutting site C. Cooling air of the electric motor 40 is used for the blower 30. As shown in FIGS. 3 and 4, the blower 30 according to this embodiment includes a blower duct 31 mounted along the left side surface of the support arm 11 from the lower part of the gear head 14. As shown in FIGS. 13 to 15, a cooling fan 41 b for motor cooling is attached to the output shaft 41 of the electric motor 40. A centrifugal fan is used as the cooling fan 41b. The cooling fan 41 b is rotated by the start of the electric motor 40, whereby outside air is taken in from the air inlets 43 d to 43 d provided on the rear surface (left side surface) of the motor housing 43. The drawn outside air flows forward to cool the electric motor 40. The cooling air having flowed to the front side of the electric motor 40 flows into the blower duct 31 from the vicinity of the lower portion of the gear head portion 14 on the side of the cooling fan 41 b.
Here, the rotational direction of the rotary blade 12 rotates in the direction indicated by the white arrow (B) in FIGS. 1 and 2. On the other hand, the rotational output of the electric motor 40 is transmitted to the spindle 17 through the two-step reduction gear train as described above. Therefore, the output rotational direction of the electric motor 40 and the rotational direction of the cooling fan 41 b are configured to coincide with the rotational direction of the rotary blade 12. In FIG. 3, FIG. 12 and FIG. 13, the output rotation direction of the electric motor 40 is shown by the white arrow (C). The cutting site C, which is the target site for dust blowing, is located on the front side of the cooling fan 41b. From this, the blower duct 31 for dust blowout can be connected to the lower part of the gear head portion 14. As a result of setting the reduction gear train to one step, when the output rotation direction of the electric motor 40 is reversed, the cooling fan 41b is also reversed, and the motor cooling air is blown forward from the top of the gear head portion 14 As a result, it is necessary to connect the same kind of blower duct to the upper part of the gear head portion 14.

According to the blower 30 of this example, the rotational output of the electric motor 40 is transmitted to the spindle 17 through the two-step reduction gear train, so that the output rotational directions of the rotary blade 12 and the electric motor 40 become the same. Wind is blown forward from the lower portion (the tangential direction of the lower portion of the cooling fan 41 b) of the gear head portion 14.
From the lower part of the gear head part 14, the support arm part 11 for supporting the said tool main body 10 with respect to the base 2 is provided in the state which protrudes ahead. The blower duct 31 is attached along the left side of the support arm 11. As shown in FIG. 14, an air guide path 32 is formed between the left side portion of the support arm portion 11 and the blower duct 31 so that the dust blowing wind flows. The support arm portion 11 is provided with a blowout port 11a for blowing out a wind for dust blow off. The blowout port 11 a is provided to penetrate in the lateral width direction of the support arm portion 11.
Further, the blowout port 11a is formed in a rectangular square tapered hole shape. The outlet 11a is formed with a tapered surface 11b which is inclined in a direction in which the flow passage area on the outlet end side (the lower side in FIG. 14) decreases. For this reason, the wind which flowed in in the blowing outlet 11a narrows the flow-path area, and blows on the cutting site C efficiently.
Thus, by blowing off the cut powder of the cut portion C by the blower 30 using the motor cooling air, the position of the rotary blade 12 with respect to the smear line drawn on the cut material W can be clearly confirmed visually At this point, accurate cutting can be performed quickly. Further, since the blower 30 utilizes the motor cooling air, it is not necessary to separately prepare a dedicated blower (blower), so that a large increase in cost is not caused.

Moreover, according to the blower 30 of this embodiment, the wind for blowing off dust (motor cooling air) is blown out toward the front side in the lower tangential direction of the cooling fan 41b. Therefore, the blower duct 31 is from the lower portion of the gear head portion 14. It is configured to be disposed substantially horizontally (laterally) along the upper surface of the base 2. For this reason, when the user visually observes the cutting site C, the blower duct 31 is hardly obstructive, so the cutting site C can be easily viewed in a comfortable posture, and the usability of the cutting tool 1 can be enhanced in this respect. On the other hand, for example, when the blower duct is disposed downward from the top of the cooling fan 41b, the blower duct interferes with visual observation of the cutting site C, and the user is forced to have a cramped posture. Become. Thus, by setting the reduction gear train to a plurality of stages (even stages) and making the rotation direction of the electric motor 40 and the cooling fan 41b the same as the rotation direction of the rotary blade 12, the blower duct 31 is moved from the lower part of the gear head portion 14 to the base. It can be disposed along the upper surface of 2 to enhance the visibility of the cutting site C.
As shown in FIGS. 12 and 13, a window 13c is formed by cutting the lower end portion of the blade case 13 at the front lower end of the blade case 13 so that the user can visually check the cut portion C. ing. The user can clearly view the cutting site C in a more comfortable posture through the window 13c.
The dust collection nozzle 33 can be attached to the window 13 c. FIG. 12 shows a state in which the dust collection nozzle 33 is attached, and FIG. 13 shows a state in which the dust collection nozzle 33 is removed. A dust collection bag or a dust collection hose of a dust collector can be connected to the dust collection nozzle 33. According to the dust collection nozzle 33, the cut powder blown off by the blower 30 can be collected efficiently, and the visibility of the cut portion C can be further enhanced.
The dust collection nozzle 33 is attached to the side of the blade case 13 with one fixing screw. In FIGS. 12 and 13, only the screw holes 34 for fastening fixing screws for fixing the dust collection nozzle 33 are shown. The dust collection nozzle 33 can be easily removed by removing the fixing screw.

[Fourth feature: Cooling structure for electrical parts]
The cooling air of the electric motor 40 is also used to cool the built-in electric components. As shown in FIG. 15, an electric component storage chamber 52 is provided at the top of the case body 13 b of the blade case 13. A controller 50 as an electrical component is accommodated in the electrical component accommodation chamber 52. The controller 50 is mainly formed by molding a control circuit board of the electric motor 40, and is partitioned from the rotary blade 12 and the gear train by a partition wall 51 which partitions the electric component storage chamber 52. By housing the controller 50 in the electric component storage chamber 52, the controller 50 is not directly affected by the heat generated in the gear train. The case body 13 b is made of resin, and the dividing wall 51 is integrally formed on the inner surface thereof. By accommodating the controller 50 in the electrical component storage chamber 52 partitioned by the resin partition wall 51, the controller 50 is electrically isolated from the surroundings.
A motor lock lever 55 is disposed between the electric component storage chamber 52 and the cooling fan 41 b of the electric motor 40. This motor lock lever 55 is shown alone in FIG. The motor lock lever 55 is for locking the output shaft 41 of the electric motor 40 in a non-rotatable manner. When the motor lock lever 55 is moved to the lock position, the rotation of the output shaft 41 is locked, whereby the rotation of the spindle 17 is locked. The convenience at the time of replacement | exchange of the rotary blade 12, etc. can be aimed at. When the motor lock lever 55 is moved to the unlock position, the locked state of the output shaft 41 is released.
The motor lock lever 55 includes an operating portion 55a, a lock groove 55b, and an urging lever 55c. As shown in FIGS. 3, 4, 12 and 13, the motor lock lever 55 crosses the output shaft 41 of the electric motor 40 in a state of being sandwiched between the motor housing 43 and the gear head housing 14 d. And is supported so as to be movable in the front-rear direction. The operating portion 55a is protruded forward. When no operation load is applied to the operation portion 55a, the motor lock lever 55 can be moved to the unlock position by the biasing force of the compression spring 56 described later. Conversely, when the operation unit 55a is pushed backward, the motor lock lever 55 can be moved to the lock position. When the motor lock lever 55 is moved to the lock position, the output shaft 41 of the electric motor 40 relatively enters the inside of the lock groove 55b. Although not shown, the output shaft 41 is provided with a two-faced width portion. The rotation of the output shaft 41 is locked by the relative movement of the two-surface width portion into the lock groove 55b. When the operation portion 55a is moved to the front side to move the motor lock lever 55 to the unlock position, the width across flats of the output shaft 41 relatively retracts from within the lock groove 55b, so that the output shaft 41 is rotated. Switch to the possible state.

A spring accommodating chamber 14e is provided between the electrical component accommodating chamber 52 and the cooling fan 41b and in the gear head housing 14d. One compression spring 56 is accommodated in the spring accommodation chamber 14e. The biasing lever portion 55c of the motor lock lever 55 is in contact with the front side (the near side in FIG. 15) of the compression spring 56. The motor lock lever 55 is urged toward the unlock position by the compression spring 56. For this reason, the operation of moving the motor lock lever 55 to the lock position side and the operation of pressing the operation portion 55 a by the user's fingertip is performed against the compression spring 56. When the user stops the pressing operation, the motor lock lever 55 is returned to the unlocked position by the biasing force of the compression spring 56.
A ventilation window portion 14f is provided on the right side wall of the spring accommodation chamber 14e. The interior of the spring accommodating chamber 14 e is in communication with the electric component accommodating chamber 52 through the ventilation window portion 14 f.
Further, a baffle plate 43c forming an annular wall portion is integrally provided on the right end surface (axial front end surface) of the motor housing 43. A cooling fan 41b is disposed on the right side and the inner peripheral side of the baffle plate 43c. The air blown out in the radial direction by the cooling fan 41 b is blown by the baffle plate 43 c to the side of the spring accommodating chamber 14 e (the front side in the motor axial direction). The wind blown into the spring accommodating chamber 14 e flows into the electrical component accommodating chamber 52 through the ventilating window portion 14 f, whereby the controller 50 (electrical component) is cooled.
By arranging the controller 50 as an electric component on the upper part of the blade case 13 and around the rotary blade 12 as described above, the wind generated by the rotation of the rotary blade 12 can be utilized for cooling the controller 50. .
In addition, the air generated by the cooling fan 41b for motor cooling flows into the electric component storage chamber 52 through the spring storage chamber 14e, whereby the controller 50 is also cooled. The cutting tool 1 of this example is a relatively small portable circular saw, and has a configuration in which each component is efficiently arranged in a limited space, and an existing component can be used without adding a new member in the configuration. The structure is also used to cool the electrical component 50 by effectively utilizing the member, and the cooling structure makes it possible to accommodate the electrical component 50 in the upper part of the blade case 13 which is not usually disposed, thereby further achieving the configuration It has a big feature in the point which realized compactization.

[Fifth feature: base shape]
In the cutting tool 1 of the present embodiment, a novel device is applied to the base 2 as well. As described above, the tool main body 10 is supported by the upper surface of the base 2 via the support arm 11 provided at the front end of the blade case 13 so as to be vertically tiltable via the support shaft 3. By changing the vertical position of the tool body 10 with respect to the base 2, it is possible to change the projecting dimension of the rotary blade 12 projecting to the lower surface side of the base 2, thereby changing the cutting depth for the cutting material W Can. 1 and 2 show a state in which the tool body 10 is positioned at the lowest position with respect to the base 2 to maximize the cutting depth. In this case, the projecting dimension of the rotary blade 12 from the lower surface of the base 2 is maximized. 8 and 9 show a state in which the tool body 10 is positioned at the highest position relative to the base 2 to minimize the cutting depth. In this case, the protrusion size of the rotary blade 12 from the lower surface of the base 2 is minimized. Thus, by increasing the cutting depth, it is possible to perform the cutting process or the deep groove cutting process of the thick cutting material W. By reducing the cutting depth, it is possible to cut the thin cutting material W having a thin plate thickness and to perform shallow groove cutting.
As described above, the vertical tilt position of the tool body 10 with respect to the base 2 is fixed by tightening the pick screw 4 provided on the rear end of the blade case 13. As shown in FIGS. 2, 8 and 9, a depth guide 5 is attached to the rear end of the base 2. The depth guide 5 has a thin band plate shape, and the lower end portion thereof is coupled to a support portion 6 provided at the rear end of the base 2 and supported so as to extend upward. Further, the depth guide 5 is coupled to the support portion 6 in a state where it can be tilted to the left and right via the tilt support shaft 6a.
The depth guide 5 is provided with a long guide groove 5a along its longitudinal direction. The pick screw 4 is inserted into the guide groove 5a. The pick screw 4 is tightened near the lower end of the rear surface of the blade case 13. On the rear surface of the blade case 13, a guide groove 13 d for accommodating the depth guide 5 is provided. The width dimension of the guide groove portion 13 d is set to a dimension adapted to the width dimension of the depth guide 5. Therefore, the depth guide 5 is accommodated in the guide groove portion 13d in the width direction without rattling, and is displaced relatively smoothly. When the tool body 10 is tilted upward with respect to the base 2, the depth guide 5 is displaced in a direction to retract relatively downward in the guide groove portion 13 d. When the tool body 10 is tilted downward with respect to the base 2, the depth guide 5 is displaced in a direction to relatively move upward in the guide groove portion 13 d. When the pick screw 4 is tightened, the position in the guide groove 13d of the depth guide 5 is fixed, the upper and lower tilting positions of the tool body 10 with respect to the base 2 are fixed, and the cutting depth of the rotary blade 12 is fixed.

Thus, for example, as shown in FIG. 1, the pick screw 4 constituting the mechanism for adjusting the cutting depth is in the state closest to the base 2 in the state where the cutting depth is maximized. In this case, it is conceivable that the finger interferes with the base 2 to make it difficult to pick when the user picks the pick screw 4. A device for solving this problem is applied to the base 2 of the cutting tool 1 of this embodiment.
As shown in FIG. 2 and FIG. 9 to FIG. 11, the rear end edge of the base 2 of this example is a range approximately half on the right side (partial range) and half range on the left side (remaining range) And are mutually displaced in the front and back direction. Hereinafter, the rear end edge on the right side with the shorter front and rear length is referred to as a first rear end edge E1, and the rear end edge on the long side is referred to as a second rear end edge E2. The second rear end edge E2 is located rearward of the first rear end edge E1.
In the case of the present embodiment, the first rear end edge E1 substantially coincides with the support portion 6 of the depth guide 5, and therefore, as shown in FIG. It is set to the matching position. Therefore, the pick screw 4 protrudes to the rear side beyond the first rear end edge E1 of the base 2 at the maximum cutting depth. From this, the user can easily pick and rotate the pick screw 4 without worrying that the fingertip interferes with the base 2 or the like, whereby the operability of the adjustment mechanism can be enhanced.
Further, by making the first rear end edge E1 of the base 2 shorter than the second rear end edge E2, the cutting tool 1 can be made lighter and the structure can be made compact.
On the other hand, the handle portion 20 is located above the range on the side of the second rear end edge E2 of the base 2 (the range on the almost left side of the left side). For this reason, if the range is also shortened similarly to the first rear end edge E1, the handle portion 20 largely protrudes rearward from the rear end edge of the base 2, and the stability of the cutting tool 1 is impaired. Further, the operating force for supporting the cutting tool 1 by the user during the cutting process is increased, and the operability is impaired.

In this respect, according to the illustrated base 2, the first rear end edge E1 is set which shortens the front-rear length only in the range of approximately half on the right side in the width direction, and the first rear end edge E1 is positioned at the support portion 6 In addition, the operability of the thumb screw 4 is enhanced, while a second rear end edge E2 is provided which projects to the rear side of the first rear end edge E1 for the remaining range substantially on the left side. Thus, by setting the second rear end edge E2 of the base 2 mainly in the range corresponding to the lower side of the handle portion 20, the instability of the cutting tool 1 in the backward tilt direction is eliminated and the stability thereof is achieved. It is possible to enhance the operability by increasing and reducing the operation force of the user at the time of use (the force to support the cutting tool 1).
In the case of the present embodiment, the second rear end edge E2 is set to the rear side of the finger rest portion 21a of the switch lever 21. For this reason, when the user places the forefinger F2 on the switch lever 21 and pulls the switch lever 21, even if a force in the direction of pushing down the handle portion 20 is applied by the reaction, the stable posture does not cause the cutting tool 1 to tilt backward. (A posture in which the base 2 is in contact with the upper surface of the cutting material W) can be held.
Next, at the front of the base 2, an inclined support wall 7 is provided on which the inclination angle of the tool body 10 is marked. The angular guide 8 is supported by the inclined support wall 7 so as to be vertically tiltable via the inclined support shaft 8a. The bracket 2 a is fixed to the angular guide 8. As shown in FIG. 10, the bracket 2a has a bifurcated shape, and is coupled to the tip of the support arm 11 with the support arm 11 of the blade case 13 sandwiched from both left and right sides.
The inclined support shaft 8a of the angular guide 8 is located coaxially with the rear inclined support shaft 6a. The pick screw 9 is tightened into the angular guide 8 through the arc-shaped insertion slot 7 a of the inclined support wall 7. For this reason, when the pick screw 9 is loosened, the angular guide 8 can be inclined about the inclined support shaft 8a, whereby the tool body 10 mainly on the right side with the front and rear inclined support shafts 8a and 6a. Can be inclined to the left). When the thumb screw 9 is tightened, the angular guide 8 is fixed, and the tool body 10 is fixed at a right angle cutting position or an inclined position at a constant angle. The beveling mechanism of the tool body 10 can be adjusted independently of the above-described mechanism for adjusting the cutting depth.

[Sixth Feature: Support Structure of Movable Cover]
Next, a portion of the rotary blade 12 that protrudes to the lower surface side of the base 2 is covered with the movable cover 16. The movable cover 16 is gradually opened as the cutting process progresses. As shown in FIG. 18, the movable cover 16 has a substantially U-shaped cross-sectional side view arc shape in order to cover the lower side periphery of the rotary blade 12 from the left and right sides. At the rear of the right side wall 16a on the right side with respect to the rotary blade 12, a knob 16b is provided for the user to manually open and close.
An annular rotation support 16 d is provided on the left side wall 16 c on the left side of the movable cutting tool 12 of the movable cover 16. The rotation support portion 16 d is rotatably supported on the outer peripheral side of the boss portion 28 of the blade case 13 which rotatably supports the spindle 17, and the movable cover 16 is coaxial with the spindle 17 and is supported by the case main body 13 b of the blade case 13. It is rotatably supported.
The movable cover 16 is biased toward the closing side by a tension spring 45. A spring hooking hole 16e is provided on the side of the rotation support 16d. One end 45a of the tension spring 45 is hooked on the spring hooking hole 16e. The other end 45b of the tension spring 45 is hooked to the blade case 13 side. As shown in FIG. 19, a spring hooking shaft 46 is provided in the vicinity of the rear end of the case body 13 b of the blade case 13. The spring hooking shaft 46 is inserted into a boss hole 47a of a boss 47 provided near the rear end of the case cover 13a. The spring hooking shaft 46 of the case body 13b and the boss 47 of the case cover 13a are integrally molded with the case body 13b and the case cover 13a, which are made of resin. When the case cover 13a is assembled to the case body 13b, the spring hooking shaft 46 is inserted into the boss hole 47a, and the case cover 13a is positioned with respect to the case body 13b.
A stepped portion 46 a having a larger diameter is provided at the base of the spring hooking shaft 46. When the case cover 13a is assembled to the case body 13b as shown in FIG. 19, the heights of the stepped portion 46a and the boss portion 47 are such that a gap K is generated between the stepped portion 46a and the boss portion 47. The dimensions are set. The spring hooking shaft 46 is exposed in the gap K between the stepped portion 46 a and the boss 47, and the other end 45 b of the tension spring 45 is hooked on this exposed portion.

As described above, since the other end 45b of the tension spring 45 is configured to be hooked on the spring hooking shaft portion 46, the labor of assembling the tension spring 45 is simplified as compared with the case of hooking this in the hole. be able to.
Further, in this example, a tension spring 45 with a wire diameter of 0.4 mm is used. On the other hand, the gap K is set to about 1 mm, and is set to a gap size slightly larger than the wire diameter of the tension spring 45. Therefore, it is possible to minimize the displacement in the axial direction (vertical direction in FIG. 19) while facilitating the hooking work of the other end side 45b of the tension spring 45 with respect to the spring hooking shaft portion 46.
As described above, in the relatively small cutting tool 1, since the mounting position of the tension spring 45 for biasing the movable cover 16 in the closing direction is at the back of the blade case 13, it is difficult for the operator to insert a hand and The installation work becomes difficult because it is hard to do. As illustrated in this point, the other end side 45 b of the tension spring 45 is configured not to be hooked or screwed to the hole, but to be hooked to the spring hooked shaft portion 46. Installation work can be done relatively easily.
Moreover, as illustrated, by utilizing the fact that the blade case 13 has a left and right half structure, the other end side of the tension spring 45 is hooked on the spring hooking shaft portion 46 having the mutual positioning function. The assembly work can be simplified while achieving a compact configuration.
Further, since the hooking shaft portion 46 is supported at both ends by the stepped portion 46 a and the boss portion 47, the other end side 45 b of the tension spring 45 is not inadvertently detached after being temporarily hooked.

Various modifications can be made to the embodiment described above. For example, although the chargeable cutting tool 1 in which the battery pack 22 is attached to the rear end of the handle portion 20 has been illustrated, the present invention can be similarly applied to an alternating current power supply type cutting tool. Further, the illustrated handle portion 20 is not limited to the small and light cutting tool 1 but can be applied as a handle portion of a medium or large cutting tool.
Furthermore, although the motor housing 43 of the electric motor 20 has a configuration in which a so-called draft is not provided by providing the front second half split structure, a normal draft may be provided instead of the half split structure. Even in this case, the electric motor can be provided with a function as a subgrip by forming it into a vertically long flat cylindrical shape.
Although the handle 20 is gripped by the right hand RH and the electric motor 20 is gripped by the left hand LH as the subgrip, it may be configured differently.

DESCRIPTION OF SYMBOLS 1 ... cutting tool W ... cutting material C ... cutting part 2 ... base, 2a ... bracket, 2b ... window part E1 ... 1st back end edge (short) of a base, E2 ... 2nd back end edge of a base (long)
Reference Signs List 3 support shaft 4 picking screw 5 depth guide 5a guide groove 6 support portion 6a tilt support shaft 7 tilt support wall portion 7a insertion groove hole 8 angular guide 8a tilt support shaft 10 ... Tool body 11 ... Support arm portion 11a ... Air outlet, 11b ... Tapered surface 12 ... Rotary blade, 12h ... Upper end 13 of rotary blade ... Blade case 13a ... Case cover, 13b ... Case body, 13c ... Window portion, 13d ... Guide groove portion 14: gear head portion 14a: intermediate drive gear, 14b: intermediate shaft, 14c: intermediate driven gear 14d: gear head housing, 14e: spring accommodating chamber, 14f: ventilation window portion 16: movable cover 16a: right side wall portion, 16b ... Knob portion 16c: Left side wall portion 16d: Rotating support portion 16e: Spring hooking hole 17: Spindle, 17a: Output gear 18: Receiving flange 19: Fixing flange 0 ... handle part LH ... left hand, RH ... right hand F1 ... thumb, F2 ... forefinger, F3 ... middle finger, F4 ... ring finger, F5 ... little finger, FP ... palm flat H ... handle top, R1 ... front to top area , R2 ... area from the top to the rear R3 ... front area of the switch lever, R4 ... rear area of the switch lever D3 ... width dimension of the handle portion (small), D4 ... width dimension of the handle portion (large)
Reference numeral 21 switch lever 21a finger rest 21b support shaft 22 battery pack 22a cell 22b removal button 23 lock off button 24 elastomeric resin layer 24a top surface covering portion 24b all around covering Portion 25: Leg portion 26: Switch main body 27: Fixing screw 28: Boss portion 29: Bearing 30: Blower 31: Blower duct 32: Air guide path 33: Dust collecting nozzle 34: Screw hole 40: Electric motor 41: Output shaft, 41a ... pinion gear, 41b ... cooling fan 42 ... fixed screw 43 ... motor housing 43a ... half housing (front), 43b ... half housing (rear)
43c: Baffle plate, 43d: Intake port L1: Upper and lower width of motor housing, L2: Longitudinal width of motor housing 45: Stretch spring, 45a: One end side, 45b: Other end side 46: Spring hook shaft portion, 46a: Stepped Part 47: Boss part, 47a: Boss hole K: Gap 50: Controller (electrical part)
Reference Signs List 51 partition wall 52 electrical component storage chamber 55 motor lock lever 55a operation portion 55b lock groove portion 55c biasing lever portion 56 compression spring

Claims (5)

A base to be brought into contact with the upper surface of the cutting material, and a tool body supported on the upper surface of the base, the tool body comprising a circular rotary blade that rotates with an electric motor as a drive source and a handle portion gripped by the user A cutting tool for cutting the cutting material by moving the cutting tool while moving the cutting tool while holding the handle portion and rotating the rotary blade.
Said handle portion, for the previous SL motor shaft position of the electric motor intersecting the cutting direction, wherein the blade case side portion position of the electric motor side and the electric motor of the blade case for accommodating the rotary blade Extends from the front portion located in the range between the position on the opposite electric motor side of the cooling fan disposed in the rear in the cutting traveling direction,
The handle portion is curved in a mountain shape that is convex upward in a side view when the cutting depth of the rotary blade is maximum, and the portion gripped by the user is from the rear end edge of the blade case in a side view Is also placed behind the
A controller for controlling the rotation of the electric motor is disposed on the upper side of the blade case and below the front portion of the handle portion, and the controller is arranged with respect to the rotary blade with respect to the position in the motor axial direction. a between the cooling fan, the cutting tool provided by overlapped to the motor axial direction relative to the pinion gear mounted on the output shaft of the electric motor. A cutting tool according to claim 1, wherein
A cutting tool in which the top of the handle portion is positioned behind the rotation center of the rotary blade and behind the motor axis of the electric motor.   The cutting tool according to claim 1 or 2, further comprising: a switch lever for start operation operated by a user on the lower surface of the handle portion, wherein the switch lever is connected to the rear end edge of the base. Cutting tool located on the front side also in the cutting direction.   The cutting tool according to any one of claims 1 to 3, wherein the cutting tool comprises a two-stage reduction gear train between the electric motor and a spindle on which the rotary blade is mounted.   The cutting tool according to any one of claims 1 to 4, comprising a blower for blowing off the cutting powder at the cutting site.

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