JP2018058125A - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric tool that suppresses scattering of chips while maintaining visibility. An electric power tool includes a housing that houses a motor and a fan, and a saw blade that is partially housed in the housing and can cut a material to be cut by rotation of the motor. The housing includes an air intake port that takes in the cooling air of the motor into the housing, an exhaust port that is located between the air intake port and the saw blade, and discharges the cooling air to the outside of the housing, and a cutting portion of the material to be cut by the saw blade And an opening that is defined so that an operator who is cutting the object can visually recognize, and a wall that is located between the exhaust port and the opening and prevents the cooling air from moving toward the cutting portion. [Selection] Figure 3

Description

  The present invention relates to a power tool such as a circular saw.

  An electric circular saw having a configuration in which chips on a material to be cut are scattered using cooling air of a motor is known (see Patent Document 1). In the circular saw, the cooling air of the motor is actively sent to the cutting portion of the saw blade that cuts the material to be cut, thereby blowing off the chips scattered at the cutting portion and ensuring the visibility of the marking line. .

JP 2005-103912 A

  In the circular saw having the above-described configuration, the wind is positively applied to the cutting portion to blow off the chips at the cutting portion, so that the blown off chips may adversely affect the operator. Therefore, there has been a configuration in which a shield is attached to a cover that covers the saw blade to suppress scattering of chips toward the worker. However, with the circular saw having the above-described configuration, the operator cannot directly visually recognize the cut portion from the left direction, and there is a concern that work efficiency may be reduced.

  In view of such circumstances, the present invention intends to provide an electric tool that suppresses the scattering of chips while ensuring visibility.

  An electric power tool according to the present invention includes a motor, a fan rotated by the motor, a housing that houses the motor and the fan, a part of the housing that is housed in the housing, and a material to be cut by the rotation of the motor. And the housing is positioned between the intake port and the saw blade, and an intake port that takes in the cooling air of the motor into the housing by the rotation of the fan. An exhaust port that discharges the cooling air to the outside of the housing by the rotation of the fan, and an opening that is defined so that an operator during a cutting operation can visually recognize a cutting position of the material to be cut by the saw blade, A wall portion disposed between the exhaust port and the opening portion for preventing the cooling air from moving toward the cut portion;

  With the above configuration, the wall portion prevents the motor cooling air exhausted from the exhaust port of the housing from moving toward the cutting portion of the material to be cut by the saw blade, so the cooling air for the chips generated at the cutting portion Can be prevented from scattering. In addition, since the chips do not scatter, the visibility of the cut portion of the material to be cut by the worker during the cutting operation is ensured, and the possibility that the worker is exposed to the chips is reduced.

  Preferably, the apparatus further includes a speed reduction mechanism provided between the saw blade and the motor, and the housing includes a motor housing that houses the motor and a gear cover that houses the speed reduction mechanism, and the wall The portion is provided on the gear cover. With the above configuration, the wall portion can be easily provided also in the electric power tool having the conventional configuration.

  Preferably, the wall portion projects from the gear cover in a direction opposite to the saw blade with respect to the gear cover. By the said structure, it can suppress that the cut location of the to-be-cut material by a cutting blade is exposed to the cooling air from an exhaust port, and can prevent scattering of a chip.

  Preferably, the wall portion extends so as to intersect the route on a route connecting the exhaust port and the opening. With the above configuration, the cooling air from the exhaust port can be prevented from flowing into the opening.

  Preferably, the wall portion is provided so as to be separable from the gear cover. With the above configuration, the wall portion can be easily provided in the electric power tool of the conventional configuration, and the wall portion damaged by the cooling air can be easily replaced.

  Preferably, the said wall part is curving so that the circumferential direction of the said fan may be followed. With the above-described configuration, the cooling air discharged from the exhaust port is blocked by the wall portion and is directed toward the cut portion of the material to be cut, and it is possible to achieve the prevention of chips from being scattered.

  Preferably, the cooling air is discharged from the exhaust port toward the traveling direction of the saw blade during a cutting operation. By the said structure, it can suppress that the worker in cutting work is exposed to the exhausted cooling air.

  According to the electric tool of the present invention, it is possible to ensure the visibility of the cutting location of the material to be cut by the operator during the cutting operation and to suppress the scattering of the chips generated at the cutting location. Can play.

The whole perspective view of the circular saw which is embodiment of this invention. The side view from the saw blade side of the circular saw shown in FIG. The side view from the motor housing side of the circular saw shown in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. 3. The front view of the circular saw shown in FIG. FIG. 6 is a cross-sectional view taken along line VI-VI shown in FIG. 5. The side view of the circular saw of the modification of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Here, the case where the present invention is applied to a circular saw will be described as an example. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably.

  First, the configuration of the circular saw 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6. In the following description, when referring to the direction, the description will be made based on the front, rear, left, right, up and down directions shown in the drawings. The circular saw 1 is an example of an electric tool.

  As shown in FIGS. 1 to 3, the circular saw 1 has a base 2, a housing 3, a motor 4, and a saw blade 5.

  The base 2 is a substantially rectangular plate made of metal such as aluminum, and has a bottom surface 2A that can slide on a material to be cut such as wood. The longitudinal direction of the base 2 is parallel to the cutting direction of the circular saw 1, and an opening 2 a (shown in FIG. 5) through which the saw blade 5 can protrude downward is formed on the bottom surface of the base 2.

  A guide 21 is provided at the front end of the base 2. The guide 21 is a member for aligning the saw blade 5 with a marking line drawn on the workpiece, and is provided so as to be aligned with the saw blade 5 in the cutting direction of the circular saw 1. .

  The housing 3 is located above the base 2. The housing 3 is supported by the base 2, can swing in the vertical direction with respect to the base 2, and can tilt in the left-right direction. A power cord 6 for supplying electric power to the motor 4 extends from the housing 3. Details of the housing 3 will be described later.

  The motor 4 has an output shaft 4 </ b> A and is housed in the housing 3. The motor 4 rotates when electric power is supplied.

  The saw blade 5 has a disk shape, is attached to the output shaft 4A of the motor 4 via a speed reduction mechanism, and rotates around the rotation shaft 5A. The lower part of the saw blade 5 is inserted into the opening 2a of the base 2 and protrudes downward from the bottom surface 2A. The location where the plane including the bottom surface 2A of the base 2 and the cutting edge of the saw blade 5 intersect substantially matches the cutting location X when the saw blade 5 cuts the workpiece.

  A first bevel plate 22 is erected at the front end of the base 2, and a second bevel plate 23 is erected at the rear end of the base 2.

  The first bevel plate 22 extends in the short direction (left-right direction) substantially orthogonal to the cutting direction, and has a substantially arc-shaped long hole 22a. A first locking screw 24 is inserted into the long hole 22 a of the first bevel plate 22.

  The second bevel plate 23 extends in the short direction (left-right direction) substantially orthogonal to the cutting direction, and has a substantially arc-shaped long hole. A second locking screw 25 is inserted into the long hole of the second bevel plate 23.

  The tilting position of the housing 3 with respect to the base 2 is adjusted with the first locking screw 24 and the second locking screw 25 loosened, and is fixed by tightening the first locking screw 24 and the second locking screw 25. .

  A link 26 is provided at the rear end of the base 2. The link 26 has a substantially arc shape and has a long hole 26a. A link locking screw 26 b is inserted into the long hole 26 a of the link 26. When the link locking screw 26b is loosened, the position of the housing 3 relative to the base 2 can be changed by swinging the housing 3 about the swing shaft 27. Thereby, the amount of protrusion of the saw blade 5 from the base 2 can be adjusted to change the cutting depth of the saw blade 5. On the other hand, when the link locking screw 26b is tightened, the position of the housing 3 with respect to the base 2 is fixed.

  The housing 3 includes a motor housing 31, a handle portion 32, a gear cover 33, a saw cover 34, and a protective cover 35.

  The motor housing 31 is made of, for example, resin, and has a bottomed shape in which the left and right direction is a longitudinal direction, one end side in the longitudinal direction is open and communicates with the gear cover 33, and the other end side is a substantially flat bottom 31A. It is formed. The motor housing 31 accommodates the motor 4 and the centrifugal fan 7. In the motor housing 31, the output shaft 4A of the motor 4 is disposed so as to extend in the left-right direction. The centrifugal fan 7 is attached to the output shaft 4 </ b> A of the motor 4 between the motor 4 and the saw blade 5 on the opening end side of the motor housing 31. A plurality of slit-shaped openings are formed in the bottom portion 31 </ b> A of the motor housing 31, and an air inlet 31 a that takes air into the motor housing 31 by communicating the inside and outside of the motor housing 31 is formed. Therefore, when the centrifugal fan 7 is rotated by the rotation of the motor 4, air is taken into the motor housing 31 through the air inlet 31 a, and the motor 4 is cooled as cooling air for cooling the motor 4.

  The handle portion 32 is made of the same material as the motor housing 31 and extends in the front-rear direction above the motor housing 31. The handle portion 32 is a portion that is held by an operator during cutting work. The handle portion 32 is provided with a trigger switch 36 for an operator to turn on / off the drive of the motor 4.

  The gear cover 33 is connected to the right side of the opening end portion of the motor housing 31. The gear cover 33 is made of metal, for example, and houses a rotation transmission mechanism for transmitting the rotation of the motor 4 to the saw blade 5. The rotation transmission mechanism is composed of a known speed reduction mechanism or the like, and has a transmission shaft that extends substantially parallel to the output shaft 4A of the motor 4. The left end portion of the transmission shaft is engaged with the output shaft 4 </ b> A of the motor 4. The rotation transmission mechanism has a right end portion protruding rightward from the gear cover 33, and a saw blade 5 is detachably attached to the right end portion. The rotation transmission mechanism is sealed in the gear cover 33 so as not to be directly exposed to the cooling air of the motor 4.

  The gear cover 33 has a plurality of openings formed as exhaust ports 33 a in the vicinity of the connecting portion with the motor housing 31 and in front of the motor housing 31, and is connected between the exhaust port 33 a and the motor housing 31. A passage 33c is defined. Therefore, when the centrifugal fan 7 rotates, the cooling air that has cooled the motor 4 through the motor housing 31 passes through the communication passage 33c in the gear cover 33 and is discharged to the front outside of the housing 3 through the exhaust port 33a. Further, a guide rib 37 for guiding the cooling air by preventing the diffusion of the cooling air is provided at the opening end of the exhaust port 33a.

  Further, the gear cover 33 is provided with a wall portion 38 having a predetermined thickness in front of the guide rib 37 so as to protrude leftward from the side surface portion of the gear cover 33, that is, in a direction opposite to the saw blade 5. . The wall portion 38 is provided integrally with the gear cover 33, is curved along the circumferential direction of the centrifugal fan 7, and has a predetermined length. Thus, since the wall part 38 is formed integrally with the gear cover 33, the number of parts does not increase.

  Further, the wall 38 is formed to have a predetermined length D in the left-right direction as shown in FIG. 4 when viewed from the front of the circular saw 1. The predetermined length D is shorter than the length of the guide rib 37 in the left-right direction and shorter than the thickness of the gear cover 33 protruding leftward from the saw cover 34. For this reason, the thickness at the time of forming the gear cover 33 and the wall part 38 integrally can be suppressed. Furthermore, the wall portion 38 is formed to face the exhaust port 33a so as to cover the exhaust port 33a from the front, and the cooling air discharged from the exhaust port 33a is prevented from reaching the cutting portion of the saw blade 5 and the operator. It has a shape that prevents it from heading to.

  Further, as shown in FIG. 6, the wall portion 38 has a gear cover so as to intersect a line L that connects a point X where the cutting edge of the saw blade 5 intersects the rotation center P of the centrifugal fan 7 on the bottom surface 2 </ b> A of the base 2. 33 is provided. Note that the location X also corresponds to a location where the cutting edge of the saw blade 5 actually cuts the workpiece. Therefore, in the present embodiment, in the following description, the cutting edge of the saw blade that cuts the workpiece may be proved as X. The predetermined length D has a value sufficient to prevent the cooling air discharged from the exhaust port 33a from moving toward the cutting point X.

  Therefore, the wall portion 38 blocks the traveling direction of the cooling air discharged forward from the exhaust port 33a to the outside of the gear cover 33 depending on the shape and position of the gear cover 33, thereby Change to the left.

  Further, a notch 33 b that allows the cutting portion X of the saw blade 5 that cuts the material to be cut to be visually recognized is provided at the front lower end of the gear cover 33. The cutting edge X of the saw blade is exposed from the gear cover by the notch 33b. A space defined by the notch 33b and the wall 38 is an opening S. An operator who operates the circular saw 1 and performs a cutting operation through the opening S can visually recognize the cutting portion X of the material to be cut.

  The saw cover 34 is made of, for example, metal, and is connected to the right end portion of the gear cover 33. The saw cover 34 has a substantially arc shape in side view along the outer edge of the saw blade 5. The saw cover 34 covers the upper portion of the saw blade 5 together with the gear cover 33.

  The protective cover 35 is made of resin, for example. The protective cover 35 is provided on the right side of the gear cover 33, and is rotatable along the outer edge of the saw blade 5 about the rotation shaft 5 </ b> A of the saw blade 5. A spring exists between the gear cover 33 and the protective cover 35. This spring urges the protective cover 35 against the gear cover 33 in the circumferential direction of the saw blade 5 so that the protective cover 35 covers the lower side of the saw blade 5. Thereby, in a state where the cutting operation is not performed, the protective cover 35 covers the lower part of the saw blade 5, that is, the part protruding downward from the bottom surface 2A of the base 2 except for the front part.

  Next, the operation of the circular saw 1 will be described. When the operator grasps the handle portion 32 and pushes the trigger switch 36, power supply to the motor 4 is started, and the saw blade 5 starts rotating. When the base 2 is pressed against the material to be cut and slid with respect to the material to be cut, the material to be cut is cut by the saw blade 5.

  At this time, since the centrifugal fan 7 rotates with the rotation of the motor 4, the cooling air is sucked into the motor housing 31 from the air inlet 31 a of the motor housing 31 to cool the motor 4, and the cooling air is passed through the communication path 33 c of the gear cover 33. Then, the air is discharged from the exhaust port 33a to the outside of the housing 3 and forward. The cooling air discharged from the housing 3 hits the wall portion 38 and changes its traveling direction from the front side to the left side. For this reason, the cooling air is prevented from reaching the cutting point X of the material to be cut and does not reach the worker who is performing the cutting work. Since the cut portion X is not exposed to the cooling air, scattering of chips generated at the cut portion is prevented. Furthermore, since the cooling air is exhausted forward of the circular saw but does not reach the base 2, the scattering of chips due to the cooling air hitting the base 2 reaching the cutting location along the upper surface of the base 2. Is prevented.

  In addition, the operator can directly view the cut portion X of the material to be cut by the saw blade 5 through the opening S during the cutting operation. At this time, since chips do not scatter from the cut portion X, the visibility of the cut portion X by the operator is improved.

  Further, even when fine dust is drifting in the space above the base 2 and to the left of the opening S due to convection, it can be removed by the cooling air whose traveling direction is changed to the left. Therefore, the substance that becomes an obstacle when the operator visually recognizes the cut portion X can be removed. This effect is an effect caused by guiding the cooling air exhausted in front of the motor housing 31 in a direction away from the saw blade 5. This makes it possible to shorten the path of the air path and realize a compact cooling air guide structure as compared with, for example, a mode in which the cooling air exhausted upward, downward, and rearward is guided to the left of the opening S. Further, since the wall portion 38 is curved along the circumferential direction of the centrifugal fan 7, the distance from the centrifugal fan 7 to the wall portion 38 is substantially the same in the circumferential direction, and when receiving cooling air. The pressure load acting on the wall portion 38 can be made uniform.

  In this way, the blowing of the cooling air of the motor 4 discharged from the exhaust port 33a to the cutting portion X is prevented, and the effect of preventing chips from scattering at the cutting portion X is achieved. Further, since the chips do not scatter from the cut portion X, a high dust collection rate can be expected even when, for example, a dust collector is connected to a circular saw to collect the chips.

  Furthermore, since the cutting portion X is not covered with the gear cover 33 and can be visually recognized by an operator who is performing the cutting operation, the material to be cut can be cut with high accuracy.

  Next, FIG. 7 shows a modification of the circular saw of the first embodiment. In the first embodiment, the wall portion 38 is provided integrally with the gear cover 33. However, in the second embodiment, the wall portion 48 is configured as a separate member that is detachable from the gear cover 33. . By providing the wall portion 48 as a separate member from the gear cover 33, the wall portion 48 can be removed when cleaning around the exhaust port 33a, so that maintenance is facilitated. Note that this modification also has the same effect as the first embodiment.

  In addition, in this invention, the shape of a wall part and the attachment location with respect to a housing are not limited to the said embodiment limitation. The wall portion can take any shape that can prevent the cooling air from reaching the cutting location X from the exhaust port 33a, and the mounting location can be an appropriate location on the housing as long as the location is also effective. Can be attached to.

    1: Circular saw, 4: Motor, 7: Centrifugal fan, 3: Housing, 5: Saw blade, 31a: Inlet, 33a: Exhaust, 38, 48: Wall, S: Opening, X: Cutting location

Claims (7)

A motor,
A fan rotated by the motor;
A housing for housing the motor and the fan;
A saw blade partially accommodated in the housing and capable of cutting a workpiece by rotation of the motor;
Have
The housing is
An intake port that takes in the cooling air of the motor into the housing by rotation of the fan;
An exhaust port that is located between the intake port and the saw blade and exhausts the cooling air to the outside of the housing by rotation of the fan;
An opening defined so that an operator who is cutting work can visually recognize the cutting position of the workpiece by the saw blade;
An electric power tool, comprising: a wall portion that is positioned between the exhaust port and the opening and prevents the cooling air from moving toward the cut portion. A further reduction mechanism provided between the saw blade and the motor;
The housing includes a motor housing that houses the motor, and a gear cover that houses the speed reduction mechanism,
The power tool according to claim 1, wherein the wall portion is provided on the gear cover.   The power tool according to claim 2, wherein the wall portion projects from the gear cover in a direction opposite to the saw blade with respect to the gear cover.   The power tool according to claim 3, wherein the wall portion extends so as to intersect the route on a route connecting the exhaust port and the opening.   The power tool according to any one of claims 2 to 4, wherein the wall portion is provided so as to be separable from the gear cover.   The electric tool according to claim 1, wherein the wall portion is curved along the circumferential direction of the fan.   The electric power tool according to any one of claims 1 to 6, wherein the cooling air is discharged from the exhaust port toward a traveling direction of the saw blade during a cutting operation.

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