JP6822605B2 - Cutting machine - Google Patents

Description

The present invention relates to a cutting machine.

Conventionally, an electric circular saw has been widely used as a cutting machine for cutting wood, pipes and the like (material to be cut). For example, in Patent Document 1, as an example of such an electric circular saw, a plurality of gears are provided in a rotational force transmission mechanism for transmitting the rotational force of the motor to the output shaft, and the rotational force of the motor is transmitted by meshing the gears. The electric circular saw to be used is disclosed.

In the electric circular saw described in Patent Document 1, when the rotation of the motor is transmitted to the output shaft, the speed is reduced by a metal gear, so that noise may be generated due to the meshing of the gears.

In order to deal with such a situation, a configuration has been proposed in which a belt is used to transmit the rotational force.

Japanese Unexamined Patent Publication No. 2011-011283

However, compared to the conventional gear meshing method, in the case of the belt transmission method, it is necessary to keep a distance between the pulleys. Therefore, when the belt transmission method is adopted in the electric circular saw as described above, the cutting machine main body becomes There is a risk of becoming large. Also, if a pulley with a large diameter is attached to the output shaft, the cutting depth may decrease. Therefore, when decelerating the rotation of the motor and transmitting it to the output shaft, multiple belts are provided. It is necessary to decelerate in stages, but there is a risk that the cutting machine body will become larger and it will be difficult to assemble.

Therefore, an object of the present invention is to prevent the cutting machine body, which has high quietness, from becoming large in size. Another object of the present invention is to provide a cutting machine capable of improving assembling property.

In order to solve the above problems, the present invention comprises a housing, a motor supported by the housing and having a rotating shaft, a first pulley provided on the rotating shaft and rotating integrally with the rotating shaft, and the first pulley. A second pulley formed to have a larger diameter, a first belt stretched between the first pulley and the second pulley, and transmitting the rotation of the first pulley to the second pulley, and the second pulley. A cutting blade that rotates by transmitting the rotation of the pulley is provided, and the material to be processed can be cut by moving the cutting blade in the cutting direction, and at least a part of the first pulley is said. Provided is a cutting machine characterized in that it is at the same position as at least a part of the second pulley in the axial direction of the output shaft and the direction orthogonal to the cutting direction.

According to the above configuration, it is possible to prevent the size of the cutting machine from becoming large in the axial direction of the output shaft and the direction orthogonal to the cutting direction.

Further, an intermediate shaft supported by the housing and supporting the second pulley, and an intermediate shaft provided on the intermediate shaft that rotates about the axis and is formed to have a smaller diameter than the second pulley and integrally rotates with the second pulley. A third pulley to be rotatably supported by the housing and an output shaft to which the cutting blade can be mounted, and an output shaft provided on the output shaft having a diameter larger than that of the third pulley and smaller than that of the second pulley. A fourth pulley that is formed and rotates integrally with the output shaft, and a second belt that is stretched between the third pulley and the fourth pulley and transmits the rotation of the third pulley to the fourth pulley. Further, it is preferable that at least a part of the second pulley is in the same position as at least a part of the fourth pulley in the cutting direction.

With such a configuration, it is possible to prevent the size of the cutting machine from becoming large in the cutting direction.

Further, in the axial view, it is preferable that each of the rotation center of the first pulley and the rotation center of the second pulley are located at positions overlapping with the cutting blade.

According to such a configuration, in the axial view of the output shaft, at least a part of the rotating shaft and the intermediate shaft is arranged so as to overlap the side surface of the cutting blade, so that the size of the cutting machine becomes large. It becomes possible to suppress.

Further, in the axial view, a first line segment connecting the axis of the rotating axis and the axis of the intermediate axis, a second line segment connecting the axis of the intermediate axis and the axis of the output axis, and the rotation. The internal angle formed by the first line segment and the second line segment in the triangle formed by the third line segment connecting the axis of the axis and the axis of the output shaft is preferably 90 degrees or less.

With such a configuration, it is possible to suppress an increase in the size of the cutting machine in the cutting direction and the size of the cutting machine in the axial direction of the output shaft and the direction orthogonal to the cutting direction.

Further, the internal angle formed by the second line segment and the third line segment in the triangle is preferably 90 degrees or less.

With such a configuration, it is possible to suppress an increase in the size of the cutting machine in the cutting direction and the size of the cutting machine in the axial direction of the output shaft and the direction orthogonal to the cutting direction.

Further, each of the internal angles in the triangle is preferably 90 degrees or less.

According to such a configuration, it is possible to suppress an increase in the size of the cutting machine in the cutting direction and the size of the cutting machine in the axial direction of the output shaft and the direction orthogonal to the cutting direction.

It further has a base that supports the housing and moves in the cutting direction on the work piece to cut the work piece, with the intermediate shaft at a position distant from the base than the rotation shaft. It is preferably supported by the housing.

According to such a configuration, since the intermediate shaft to which the pulley having a relatively large diameter is attached is separated from the base, it is possible to secure a sufficient cutting depth.

Further, a pulley case having a wall portion that is recessed in the axial direction of the output shaft and forms a recess for accommodating the first belt and the second belt, and a regulation wall that regulates contact between the first belt and the second belt. It is preferable that the motor further has a motor main body portion and is arranged in the axial direction in the order of the second belt, the regulation wall, the first belt, the wall portion, and the motor main body portion.

According to such a configuration, in order for the regulation wall to restrict the contact between the first belt and the second belt, both the first belt and the second belt are arranged in the recess from one side of the wall portion of the pulley case. Is possible. This makes it possible to improve the assemblability.

Further, the first belt and the second belt are preferably timing belts, and the first pulley, the second pulley, the third pulley and the fourth pulley are preferably timing pulleys.

According to such a configuration, even when a high load is generated on the cutting blade, the occurrence of rattling or the like is suppressed, so that efficient and stable cutting work can be performed. Further, by using the timing belt and the timing pulley, the rotation transmission efficiency is improved as compared with the friction transmission type belt, the slip of the belt can be suppressed, and the damage of the belt is suppressed, so that the durability of the tool is suppressed. The sex is improved.

The present invention further comprises a housing, a motor supported by the housing and having a rotating shaft, a first pulley provided on the rotating shaft and rotating integrally with the rotating shaft, and a driven shaft supported by the housing. A second pulley provided on the driven shaft, which rotates about the axis of the driven shaft and is formed to have a diameter larger than that of the first pulley, is stretched on the first pulley and the second pulley, and is stretched on the first pulley. A first belt that transmits the rotation of one pulley to the second pulley, a cutting blade that rotates by transmitting the rotational force of the second pulley, and a housing that supports the housing and projects a part of the cutting blade downward. It has a base having a hole for making the cutting blade, the rotation center of the cutting blade is located below the rotation center, and the rotation center of the second pulley is located above the rotation center of the first pulley. We provide a cutting machine characterized by this.

According to the above configuration, by intentionally moving the position of the second pulley away from the rotation center of the cutting blade, it is possible to facilitate the arrangement of the large second pulley and prevent the size of the cutting machine from becoming large. It will be possible.

Further, a third pulley that rotates integrally with the second pulley, a fourth pulley to which the rotational force of the third pulley is transmitted, and a second belt stretched over the third pulley and the fourth pulley. The center of rotation of the fourth pulley is preferably located below the center of rotation of the second pulley.

With such a configuration, it is possible to prevent the size of the cutting machine from becoming large in the cutting direction.

Further, in the axial view, it is preferable that at least a part of each of the rotating shaft and the driven shaft is located at a position where it overlaps with the cutting blade.

According to such a configuration, in the axial view of the output shaft, at least a part of the rotating shaft, the first intermediate shaft and the second intermediate shaft is arranged so as to overlap the side surface of the cutting blade, so that the size of the cutting machine It becomes possible to suppress the increase in size.

Further, when the axial direction of the output shaft and the direction orthogonal to the cutting direction are the vertical directions, the first pulley is preferably located above the lower end of the second pulley and below the upper end.

Further, when the cutting direction is the front-rear direction, the fourth pulley is preferably located behind the front end of the second pulley and in front of the rear end.

Further, the first belt is preferably a timing belt.
The present invention further forms a housing, a motor supported by the housing and having a rotating shaft, a first pulley provided on the rotating shaft and rotating integrally with the rotating shaft, and a diameter larger than that of the first pulley. The second pulley is stretched between the first pulley and the second pulley, and is supported by the housing and the first belt that transmits the rotation of the first pulley to the second pulley. An intermediate shaft that supports the pulley, a third pulley that is provided on the intermediate shaft and has a diameter smaller than that of the second pulley, and that rotates integrally with the second pulley about the axis of the intermediate shaft, and the housing. An output shaft that is rotatably supported, a fourth pulley that is provided on the output shaft and has a diameter larger than that of the third pulley and a diameter smaller than that of the second pulley and that rotates integrally with the output shaft. A second belt that is stretched between the third pulley and the fourth pulley and transmits the rotation of the third pulley to the fourth pulley and can be attached to the output shaft to transmit the rotation of the fourth pulley. A circular cutting blade that is rotated and is provided, and the work material can be cut by moving the cutting blade in the cutting direction, and the second pulley is at least partially in the cutting direction. The third pulley is located at the same position as at least a part of the fourth pulley and is located outside the outer diameter of the cutting blade in the axial view of the motor, and the third pulley is in the axial direction of the motor. Provided is a cutting machine characterized in that it is visually located within the outer diameter of the cutting blade.
In the above configuration, it is preferable that at least a part of the first pulley is at the same position as at least a part of the second pulley in the axial direction of the output shaft and the direction orthogonal to the cutting direction.
The present invention further comprises a housing, a motor supported by the housing and having a rotating shaft, a first pulley provided on the rotating shaft and rotating integrally with the rotating shaft, and a driven shaft supported by the housing. A second pulley provided on the driven shaft, which rotates about the axis of the driven shaft and is formed to have a diameter larger than that of the first pulley, is stretched on the first pulley and the second pulley, and is stretched on the first pulley. A first belt that transmits the rotation of one pulley to the second pulley, a third pulley that rotates integrally with the second pulley, a fourth pulley that transmits the rotational force of the third pulley, and the third pulley. And a second belt stretched over the fourth pulley, a cutting blade that rotates by transmitting the rotational force of the fourth pulley, and a part of the cutting blade that supports the housing and lowers. It has a base having a hole for projecting to, and it is possible to cut the work material by moving the cutting blade in the cutting direction, and the rotation center of the first pulley is set to the motor. The center of rotation of the cutting blade is located within the outer diameter of the cutting blade when viewed in the axial direction of the motor, and is within the outer diameter of the cutting blade when viewed in the axial direction of the motor, and the rotation of the first pulley. It is positioned below the center, and the rotation center of the second pulley is positioned within the outer diameter of the cutting blade and above the rotation center of the first pulley when viewed in the axial direction of the motor. Provide a characteristic cutting machine.

According to the cutting machine of the present invention, it is possible to prevent the cutting machine body from becoming large. In addition, it is possible to improve the assembling property while ensuring the quietness.

It is a right side view which shows the appearance of the electric circular saw which concerns on 1st Embodiment of this invention. (A) is a plan view of the electric circular saw according to the first embodiment of the present invention, and a partial cross section is shown. (B) is a right side view showing the cutting depth adjusting mechanism of the base of the electric circular saw according to the first embodiment of the present invention. It is a left side view which shows the appearance of the electric circular saw which concerns on 1st Embodiment of this invention, and shows a partial cross section of a handle part. It is an enlarged view of the cutting depth adjustment mechanism of the electric circular saw which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the state which the 1st stage transmission mechanism of the electric circular saw which concerns on 1st Embodiment of this invention is housed in a pulley accommodating part. It is a perspective view which shows the state which the power transmission part and the belt contact regulation part of the electric circular saw which concerns on 1st Embodiment of this invention are housed in a pulley accommodating part. It is a perspective view which shows the appearance of the pulley accommodating part of the electric circular saw which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the positional relationship of the motor shaft, the intermediate shaft and the spindle in the right side view. FIG. 8 is a sectional view taken along line IX-IX of FIG. FIG. 8 is a cross-sectional view taken along line XX of FIG. It is sectional drawing which passes through the axis of the intermediate axis of the electric circular saw which concerns on 1st Embodiment of this invention and is parallel to the axis of the intermediate axis. It is a right side view which shows the positional relationship of the motor shaft, the intermediate shaft and the spindle of the electric circular saw which concerns on 1st Embodiment of this invention. It is a figure (the 1) explaining the process of assembling the power transmission part of the electric circular saw which concerns on 1st Embodiment of this invention to a pulley case. It is a figure (the 2) explaining the process of assembling the power transmission part of the electric circular saw which concerns on 1st Embodiment of this invention to a pulley case. It is a figure (the 3) explaining the process of assembling the power transmission part of the electric circular saw which concerns on 1st Embodiment of this invention to a pulley case. It is a figure (the 4) explaining the process of assembling the power transmission part of the electric circular saw which concerns on 1st Embodiment of this invention to a pulley case. It is a figure (the 5) explaining the process of assembling the power transmission part of the electric circular saw which concerns on 1st Embodiment of this invention to a pulley case. It is a figure (the 6) explaining the process of assembling the power transmission part of the electric circular saw which concerns on 1st Embodiment of this invention to a pulley case. It is a right side view which shows the positional relationship of the motor shaft, the 1st intermediate shaft, the 2nd intermediate shaft and the spindle of the electric circular saw which concerns on 2nd Embodiment of this invention. It is sectional drawing which passes through each axis of the motor shaft, the 1st intermediate shaft, the 2nd intermediate shaft, and the spindle of the power transmission part of the electric circular saw which concerns on 2nd Embodiment of this invention. It is a figure explaining the effect of the electric circular saw which concerns on the 2nd Embodiment of this invention.

An electric circular saw 1 which is an example of an electric tool according to an embodiment of the present invention will be described with reference to FIGS. 1 to 17. The electric circular saw 1 is an electric tool for cutting a material to be cut such as wood by using a circular saw blade P.

In the following description, "front" shown in the figure is defined as forward, "rear" is defined as backward, "up" is defined as upward, and "down" is defined as downward. Further, when the electric circular saw 1 is viewed from the rear, "right" is defined as the right direction, and "left" is defined as the left direction. When the dimensions, numerical values, etc. are referred to in the present specification, not only the dimensions and numerical values that completely match the dimensions and numerical values, but also the dimensions, numerical values, etc. that substantially match (for example, when it is within the range of manufacturing error). ) Shall be included. Similarly for "identical", "orthogonal", "parallel", "match", "plane", etc., "substantially identical", "substantially orthogonal", "substantially parallel", "substantially match", "substantially flush", etc. Etc. shall be included.

As shown in FIGS. 1 to 3, the electric circular saw 1 mainly includes a base 2, a housing 3, a cutting depth adjusting mechanism 4, a motor 5, a power transmission unit 6, and a belt contact regulation unit 7. doing.

As shown in FIGS. 1 to 3, the base 2 supports the housing 3. The base 2 is made of a metal such as aluminum, extends in the front-rear direction, and has a substantially rectangular shape when viewed from the bottom. A long hole 2A extending in the front-rear direction and allowing the circular saw blade P to enter is formed in the central portion of the base 2 in the left-right direction. The circular saw blade P extends downward from above through the elongated hole 2A. The length of the circular saw blade P protruding downward from the bottom surface of the base 2 is the depth of cut. The elongated hole 2A is an example of the "hole portion" in the present invention. The longitudinal direction of the base 2 coincides with the cutting direction when the electric circular saw 1 is used for cutting work, that is, the front-rear direction. The bottom surface of the base 2 is a sliding surface that slides against the material to be cut during cutting work. In order to cut the material to be cut during the work, the operator moves the base 2 and the housing 3 supported by the base 2 in the cutting direction while sliding the bottom surface of the base 2 on the material to be cut in the cutting direction. It is possible. As shown in FIGS. 1 and 2, the base 2 has a housing rotation support 21 and a shaft 22. Base 2 is an example of a "base" in the present invention. The material to be cut is an example of the "material to be processed" in the present invention. The anteroposterior direction is an example of the "cutting direction" in the present invention.

As shown in FIG. 1, the housing rotation support portion 21 extends upward from the upper surface of the base 2 at the front portion of the base 2. As shown in FIG. 2, the housing rotation support portion 21 has a substantially U-shape in a plan view. The shaft 22 is provided on the upper portion of the housing rotation support portion 21 and extends in the left-right direction.

As shown in FIGS. 1 to 3, the housing 3 forms the outer shell of the electric circular saw 1, and includes a motor accommodating portion 31, a substrate accommodating portion 32, a handle portion 33, a pulley accommodating portion 34, a saw cover 35, and a protective cover. It is configured to include 36. As shown in FIG. 2, a power cord 3A having a plug portion that can be connected to a commercial AC power supply extends to the left from the left rear portion of the housing 3. The power cord 3A is electrically connected to the motor 5 inside the housing 3, and by connecting the plug portion of the power cord 3A to a commercial AC power supply, power can be supplied to the motor 5. The housing 3 is an example of the "housing" in the present invention.

The motor accommodating portion 31 shown in FIGS. 2 and 3 is made of, for example, resin, and has a substantially cylindrical shape extending in the left-right direction. The motor accommodating portion 31A accommodates the motor 5.

As shown in FIGS. 1 to 3, the handle portion 33 extends in the front-rear direction above the motor accommodating portion 31. The handle portion 33 is a portion gripped by the operator during cutting work. The handle 33 is provided with a manually operable trigger switch 3B for controlling the start and stop of the motor 5.

As shown in FIG. 2A, the pulley accommodating portion 34 is provided on the right side of the motor accommodating portion 31, and the pulley accommodating portion 34 is made of, for example, metal and accommodates the power transmission unit 6. doing. Further, the pulley accommodating portion 34 is provided with a rotation restricting member 3C. Although not shown in the figure, an engaging portion having a substantially U-shaped side view is provided at the rear portion of the rotation restricting member 3C. The rotation restricting member 3C is urged forward by an urging member (not shown), and a part of the rotation restricting member 3C is configured to extend forward from the pulley accommodating portion in a state where no external force is applied. The detailed configuration of the pulley accommodating portion 34 will be described later.

The saw cover 35 shown in FIG. 1 is made of metal, for example, and is attached to a pulley accommodating portion 34. The saw cover 35 covers the upper portion of the circular saw blade P. The saw cover 35 may be made of the same material as the pulley accommodating portion 34 and may be integrally formed. A shaft 22 provided above the housing rotation support portion 21 of the base 2 is inserted through the front end portion of the saw cover 35. The saw cover 35 is rotatable about the shaft 22 with respect to the base 2. As the saw cover 35 rotates about the shaft 22 with respect to the base 2, the motor housing portion 31, the substrate housing portion 32, the handle portion 33, the pulley housing portion 34, the saw cover 35, and the protective cover 36 (housing 3) are moved. As a unit, it rotates about the shaft 22 with respect to the base 2.

The protective cover 36 is made of resin, for example, and is provided on the saw cover 35. The protective cover 36 is configured to be rotatable along the outer edge of the saw cover 35. An urging member (not shown) is provided between the saw cover 35 and the protective cover 36. The urging member urges the protective cover 36 in a direction that covers the lower side of the circular saw blade P. As a result, the protective cover 36 covers a part of the lower portion of the circular saw blade P in a state where the cutting operation is not performed.

The cutting depth adjusting mechanism 4 is configured to be able to adjust the amount of protrusion of the circular saw blade P downward from the bottom surface (long hole 2A) of the base 2, and is linked as shown in FIGS. 2 to 4. It has a section 41, a regulating section 42, and a shaft 43. The cutting depth adjusting mechanism 4 is a mechanism (relative movement adjusting mechanism) capable of adjusting the relative position of the circular saw blade P with respect to the base 2.

As shown in FIG. 2B, the lower end of the link portion 41 is fixed to the upper surface of the base 2 with screws. The link portion 41 is located outside the housing 3 and has an arc shape that protrudes upward from the upper surface of the base 2 and curves with a predetermined curvature. The link portion 41 is formed in a substantially quarter circle (quarter circle) shape. The link portion 41 is formed with an arc-shaped arc groove 41a extending upward along the link portion 41. The link portion 41 has one end portion 41A located at the position closest to the base 2 and the other end portion 41B located at the position farthest from the base 2. Further, a pressing surface 41C is defined on the front surface of the link portion 41.

As shown in FIG. 4, the shaft 43 is fixed to the housing 3 and extends in the left-right direction. The shaft 43 is inserted into the arc groove 41a of the link portion 41. In the present embodiment, the posture of the housing 3 with respect to the base 2 is changed by the shaft 43 moving along the arc groove 41a. In other words, the link portion 41 is configured to guide the relative movement of the housing 3 with respect to the base 2. That is, the housing 3 is rotatably supported with respect to the base 2, and the relative position with respect to the base 2 can be changed. According to such a configuration, the housing 3 and the base 2 can be moved relative to each other with a simple configuration. In the present embodiment, the shaft 43 moves downward along the arc groove 41a so that it can come into contact with one end 41A of the link portion 41, and the shaft 43 moves upward along the arc groove 41a. By moving, it is configured to be able to come into contact with the other end portion 41B of the link portion 41. That is, the shaft 43 is configured to be movable in a range between one end 41A and the other 41B.

The regulating portion 42 has a base portion 42A, a lever portion 42B, a cam 42C, a shaft 42D, and a pressing member 42E.

The base 42A is rotatably supported by the saw cover 35.

The lever portion 42B is integrally formed with the base portion 42A. That is, it is rotatably supported by the saw cover 35. The lever portion 42B is operated by an operator to rotate about an axis extending in the left-right direction.

The cam 42C has a tubular shape and is formed in a substantially elliptical shape in a lateral view. A base portion 42A is fitted on the inner peripheral surface of the cam 42C. As a result, the cam 42C can rotate integrally with the lever portion 42B.

The shaft 42D extends in the left-right direction and is supported by the housing 3.

The pressing member 42E has a substantially cylindrical shape extending in the left-right direction, and the shaft 42D is inserted therethrough. The inner diameter of the pressing member 42E is formed to be larger than the outer diameter of the shaft 42D, and the pressing member 42E is configured to be movable in the vertical and front-back directions with respect to the shaft 42D. In other words, the pressing member 42E is configured to engage (play) with the shaft 42D with play and to move relative to the shaft 42D. By rotating the cam 42C, the outer peripheral surface of the pressing member 42E can press the pressing surface 41C of the link portion 41, and the outer peripheral surface of the pressing member 42E can be separated from the pressing surface 41C of the link portion 41.

In the present embodiment, the outer peripheral surface of the cam 42C and the outer peripheral surface of the pressing member 42E are always in contact with each other. Therefore, by rotating the lever portion 42B in the clockwise direction of FIG. 4 (direction of arrow X in FIG. 4), the cam 42C is oriented so that the long axis direction of the cam 42C is substantially orthogonal to the pressing surface 41C of the link portion 41. Rotates in the clockwise direction of FIG. 6, and the pressing member 42E moves in a direction approaching the pressing surface 41C with the rotation of the cam 42C, and the outer peripheral surface of the pressing member 42E presses the pressing surface 41C. It is configured to be possible. When the outer peripheral surface of the pressing member 42E presses the pressing surface 41C, the relative position of the housing 3 with respect to the base 2 is fixed. Further, by rotating the cam 42C to a position where the major axis direction is substantially parallel to the pressing surface 41C of the link portion 41, the pressing member 42E moves in a direction away from the pressing surface 41C, and the outer circumference of the pressing member 42E. It is possible to release the pressing of the surface against the pressing surface 41C.

The motor 5 shown in FIG. 2 is a drive source for driving the power transmission unit 6, and is a DC brushless motor in the present embodiment. The motor 5 mainly includes a motor main body 50, a rotating shaft 51, and a fan 52. The motor 5 is an example of the "motor" in the present invention.

The motor main body 50 is housed in the motor housing 31 and extends in the left-right direction. The motor main body portion 50 is located to the left of the pulley accommodating portion 34. The motor main body 50 includes a rotor (not shown) and a stator (not shown). The motor main body 50 is an example of the "motor main body" in the present invention.

The rotating shaft 51 extends in the left-right direction and is rotatably supported by the housing 3 via a bearing about an axis A extending in the left-right direction. The rotating shaft 51 is provided with an engaged portion 51A having two surfaces parallel to each other in the left-right direction. In the present embodiment, the operator presses the rotation restricting member 3C inward of the pulley accommodating portion 34 against the urging force of the urging member (not shown), and the rotation regulating member 3C is shown. It is possible to regulate the rotation of the rotating shaft 51 by engaging the engaging portion with the engaged portion 51A. By regulating the rotation of the rotating shaft 51, the rotation of the circular saw blade P can be regulated via the power transmission unit 6, and the circular saw blade P can be preferably replaced. The rotating shaft 51 is an example of the "rotating shaft" in the present invention. Further, the axis A is an example of the "axis of the rotating shaft" and the "center of rotation of the first pulley" in the present invention.

The fan 52 is a centrifugal fan and is fixed to the rotating shaft 51 so as to be integrally rotatable with the rotating shaft 51.

Next, a detailed configuration of the pulley accommodating portion 34, the power transmission portion 6, and the belt contact regulating portion 7 will be described.

As shown in FIGS. 5 to 7, the pulley accommodating portion 34 has a substantially semicircular shape in the left-right side view. The pulley accommodating portion 34 has a pulley case 341 and a pulley cover 342. The pulley accommodating portion 34 is an example of the "gear case" in the present invention.

As shown in FIGS. 5 to 7, the pulley case 341 includes a first left wall 341A, a second left wall 341B, a third left wall 341C, a first peripheral wall 341D, and a second peripheral wall 341E. , The fourth left wall 341S is mainly provided. The pulley case 341 is an example of the "pulley case" in the present invention.

The first left wall 341A extends in the vertical and front-back directions. As shown in FIG. 9, a through hole 341a is formed in the front portion of the first left wall 341A, and a protrusion 341G is provided in the rear portion of the first left wall 341A. The first left wall 341A is an example of the "wall portion" in the present invention.

The through hole 341a penetrates the first left wall 341A in the left-right direction. A bearing 34A is fitted in the through hole 341a. The rotating shaft 51 of the motor 5 is rotatably supported by the pulley case 341 via a bearing 34A.

The protrusion 341G protrudes to the right from the right side of the first left wall 341A and has a substantially circular shape when viewed from the right side. A bearing 34B is fitted on the inner peripheral surface of the protrusion 341G.

As shown in FIG. 5, the second left wall 341B extends in the vertical and front-back directions and is located to the right of the first left wall 341A. The second left wall 341B is formed with a female screw hole 341B1 extending to the left from the right surface of the second left wall 341B. Further, as shown in FIGS. 5 and 10, a recess 341b is formed in the second left wall 341B.

The recess 341b is formed so as to be recessed from the right side of the second left wall 341B to the left. A needle bearing 34D is fitted on the inner peripheral surface of the recess 341b.

As shown in FIG. 5, the third left wall 341C extends in the vertical and front-back directions, and is located to the right of the first left wall 341A and the second left wall 341B. The third left wall 341C is formed with a female screw hole 341C1 extending to the left from the right surface of the third left wall.

The fourth left wall 341S extends in the vertical and front-back directions, and is located to the right of the first left wall 341A, the second left wall 341B, and the third left wall 341C.

As shown in FIG. 5, the first peripheral wall 341D extends to the right so as to connect the right side of the first left wall 341A and the right side of the second left wall 341B. The inner peripheral surface of the front portion of the first peripheral wall 341D is curved with a predetermined curvature.

The second peripheral wall 341E extends to the right so as to connect the right surface of the second left wall 341B and the right surface of the third left wall 341C. The inner peripheral surfaces of the first peripheral wall 341D and the second peripheral wall 341E are formed flush with each other and are curved with a predetermined curvature.

The third peripheral wall 341F extends to the right so as to connect the right surface of the third left wall 341C and the right surface of the fourth left wall 341S.

As shown in FIG. 7, the pulley cover 342 is formed to be slightly larger than the shape formed by the contour line of the third peripheral wall 341F in the right side view, and is press-fitted and screwed from the right side of the pulley case. It is fixed to the pulley case 341. The pulley cover 342 has a protruding portion 342A, a first cylindrical portion 342B, and a second cylindrical portion 342C.

As shown in FIGS. 7, 9 and 10, the protruding portion 342A has a bottomed cylindrical shape protruding from the right surface of the pulley cover 342 to the right. A needle bearing 34C is fitted in the protrusion 342A.

The first cylindrical portion 342B has a cylindrical shape protruding from the right surface of the pulley cover 342 to the right. As shown in FIG. 10, a bearing 34E is fitted in the first cylindrical portion 342B.

The second cylindrical portion 342C has a cylindrical shape extending from the right surface of the first cylindrical portion 342B to the right. The inner diameter of the second cylindrical portion 342C is formed to be smaller than the inner diameter of the first cylindrical portion 342B.

Further, as shown in FIG. 5, a transmission mechanism accommodating space 34a that is recessed to the left from the third left wall 341C of the pulley case 341 in a stepped manner is provided. More specifically, the transmission mechanism accommodation space 34a is a space defined by the left surfaces of the first left wall 341A, the second left wall 341B, the first peripheral wall 341D, the second peripheral wall 341E, and the pulley cover 342. The transmission mechanism accommodation space 34a is an example of a "recess" in the present invention.

As shown in FIGS. 5 and 6, the power transmission unit 6 is a portion that transmits the rotation of the motor 5 to the circular saw blade P by the two-stage belt system, and is the first pulley 61, the intermediate shaft 62, and the second. It includes a 2-pulley 63, a first belt 64, a third pulley 65, a spindle 66, a fourth pulley 67, and a second belt 68. Of these, the first pulley 61, the second pulley 63, and the first belt 64 form the first-stage transmission mechanism, and the third pulley 65, the fourth pulley 67, and the second belt 68 are the second-stage transmission mechanism. It constitutes a transmission mechanism. Further, the first-stage transmission mechanism and the second-stage transmission mechanism are housed in the transmission mechanism accommodation space 34a.

The first pulley 61 is a timing pulley, which has a substantially cylindrical shape extending in the left-right direction, and has a gear-shaped unevenness formed on the outer peripheral surface. As shown in FIG. 9, the first pulley 61 is fixed to the rotating shaft 51 of the motor 5 by press fitting on the right side of the first left wall 341A of the pulley case 341, and rotates integrally with the rotating shaft 51. The first pulley 61 is an example of the "first pulley" in the present invention.

The intermediate shaft 62 has a substantially cylindrical shape, and is arranged so as to extend in the left-right direction in parallel with the rotating shaft 51. As shown in FIG. 9, the intermediate shaft 62 is rotatably supported by the pulley case 341 via the bearing 34B and rotatably supported by the pulley cover 342 via the needle bearing 34C. The intermediate shaft 62 rotates about an axis B extending in the left-right direction. The intermediate shaft 62 is an example of the “intermediate shaft” in the present invention.

The second pulley 63 shown in FIG. 5 is a timing pulley, which has a substantially cylindrical shape extending in the left-right direction, and has a gear-shaped unevenness formed on the outer peripheral surface. The second pulley 63 has an outer diameter larger than the outer diameter of the first pulley 61. The second pulley 63 is fixed by press fitting to the left side of the central portion of the intermediate shaft 62, and rotates about the axis B integrally with the intermediate shaft 62. The second pulley 63 is formed with a plurality of female screw holes 63a extending from the right surface to the left. The second pulley 63 is an example of the "second pulley" in the present invention. The axis B is an example of the "axis of the intermediate axis" and the "center of rotation of the second pulley" in the present invention.

The first belt 64 is an endless belt made of resin formed in an endless shape, and is a timing belt having gear-shaped irregularities formed on the inner peripheral surface. The first belt 64 is stretched between the first pulley 61 and the second pulley 63 by bridging the front portion thereof to the outer circumference of the first pulley 61 and the rear portion over the outer circumference of the second pulley 63. .. The first belt 64 is an example of the "first belt" in the present invention.

The third pulley 65 is a timing pulley, has a cylindrical shape extending in the left-right direction, and has a gear-shaped unevenness formed on the outer peripheral surface. The third pulley 65 has an outer diameter smaller than the outer diameter of the second pulley 63. The third pulley 65 is fixed by press fitting to the right side of the central portion of the intermediate shaft 62, and rotates about the axis B integrally with the intermediate shaft 62. The third pulley 65 is an example of the "third pulley" in the present invention.

As shown in FIG. 6, the spindle 66 is arranged so as to extend in the left-right direction parallel to the rotating shaft 51 and the intermediate shaft 62, and is rotatably supported by the pulley case 341 via the needle bearing 34D. , Is rotatably supported by the pulley cover 342 via the bearing 34E (see FIG. 10). The spindle 66 rotates about an axis C extending in the left-right direction. A mounting portion 66A for mounting the circular saw blade P is provided at the right end portion of the spindle 66. The mounting portion 66A projects to the right side (outside) of the pulley cover 342. The spindle 66 is an example of the "output shaft" in the present invention.

The fourth pulley 67 is a timing pulley, which has a substantially cylindrical shape extending in the left-right direction, and has a gear-shaped unevenness formed on the outer peripheral surface. The fourth pulley 67 has an outer diameter larger than the outer diameter of the third pulley 65. Further, the fourth pulley 67 has an outer diameter smaller than that of the second pulley 63. The fourth pulley 67 is fixed by press fitting to the left side of the central portion of the spindle 66, and rotates about the axis C integrally with the spindle 66. The fourth pulley 67 is an example of the "fourth pulley" in the present invention. Further, the axis C is an example of the "axis of the output shaft", the "center of rotation of the fourth pulley", and the "center of rotation of the cutting blade" in the present invention.

The second belt 68 is a resin-made endless belt formed in an endless shape, and is a timing belt in which gear-shaped irregularities are formed on the inner peripheral surface. The second belt 68 is stretched between the third pulley 65 and the fourth pulley 67 by bridging the upper portion thereof to the outer circumference of the third pulley 65 and the lower portion thereof to the outer circumference of the fourth pulley 67. The second belt 68 is an example of the "second belt" in the present invention.

The circular saw blade P has a substantially disk shape, is detachably fixed to the mounting portion 66A of the spindle 66, and is rotatably supported together with the spindle 66. The circular saw blade P is an example of the "cutting blade" in the present invention.

As described above, the first-stage transmission mechanism (first pulley 61, second pulley 63 and first belt 64) and the second-stage transmission mechanism (third pulley 65, fourth pulley 67 and second belt 68) Consists of a timing pulley and a timing belt. According to this, even when a high load is generated on the circular saw blade P, the occurrence of rattling or the like is suppressed, so that efficient and stable cutting work can be performed. Further, by using the timing belt and the timing pulley, the transmission efficiency of rotation is improved and the damage of the belt is suppressed, so that the durability of the tool is improved.

The belt contact restricting unit 7 shown in FIG. 6 has a configuration for restricting contact between the first belt 64 and the second belt 68, and has a first plate 71 and a second plate 72. There is. The belt contact regulation unit 7 is an example of the “regulation wall” in the present invention.

The first plate 71 has a substantially rectangular flat plate shape. A plurality of female screw holes 71a are formed in the first plate 71. The first plate 71 is fixed to the second left wall 341B of the pulley case 341 by using a plurality of male screws. As shown in FIGS. 6 and 9, the first plate 71 has a cylindrical portion 71A.

The cylindrical portion 71A has a bottomed cylindrical shape extending from the right surface of the first plate 71 to the right. A needle bearing 71B is fixed to the inner peripheral surface of the cylindrical portion 71A. The cylindrical portion 71A supports the right end of the rotating shaft 51 of the motor 5 via the needle bearing 71B. By supporting the rotating shaft 51 on the cylindrical portion 71A and fixing the first plate 71 to the pulley case 341, it is possible to suitably suppress the rotating shaft 51 from tilting in the left-right direction.

The second plate 72 shown in FIG. 6 has a substantially disk shape, and a plurality of female screw holes 72a are formed in the second plate 72. The second plate 72 is fixed to the second pulley 63 from the right side by using a plurality of male screws. As shown in FIGS. 9 and 10, the second plate 72 has a regulating portion 72A and a protruding portion 72B. Further, an insertion hole through which the intermediate shaft 62 is inserted is formed in a substantially central portion of the second plate 72.

The regulating portion 72A forms the outer edge portion of the second plate 72, and is provided so as to prevent the first belt 64 from falling off from the second pulley 63. The outer diameter of the regulating portion 72A is formed to be slightly larger than the outer diameter of the second pulley 63.

The protruding portion 72B has a substantially annular shape when viewed from the right side, and slightly protrudes to the right of the other portion of the second plate 72. In the present embodiment, as shown in FIG. 11, the protruding portion 72B protrudes to the right by the width D1 from the other portion of the second plate 72. As a result, when the second belt 68 moves (rotates) relative to the second plate 72, the side surface in the width direction of the second belt 68 when the second belt 68 and the second plate 72 come into contact with each other. The contact area between (left surface) and the right surface of the second plate 72 (see D2 in the figure) can be reduced. According to such a configuration, it is possible to suppress damage to the second belt 68 due to frictional heat or the like generated by the contact between the second belt 68 and the second plate 72.

Further, in the present embodiment, by providing the belt contact restricting unit 7, the first belt 64 and the second belt 68 can be arranged so as to overlap each other in the front view.

Specifically, as shown in FIG. 12, at least a part of the first pulley 61 is located at substantially the same position as at least a part of the second pulley 63 in the vertical direction. In other words, at least a part of the first pulley 61 is located at substantially the same position as the second pulley 63 in the direction orthogonal to the axis C direction and the front-rear direction (cutting direction) of the spindle 66. More specifically, in the present embodiment, substantially all of the first pulley 61 is located at substantially the same position as a part of the second pulley 63 in the vertical direction. In other words, the first pulley 61 is located above the lower end of the second pulley 63 and below the upper end of the second pulley 63. According to such a configuration, it is possible to prevent the size of the electric circular saw 1 from becoming large in the direction orthogonal to the axis C direction and the cutting direction (vertical direction) of the spindle 66.

Further, at least a part of the second pulley 63 is located at substantially the same position as at least a part of the fourth pulley 67 in the front-rear direction. In other words, at least a part of the second pulley 63 is located at substantially the same position as at least a part of the fourth pulley 67 in the cutting direction. More specifically, in the present embodiment, substantially all of the fourth pulley 67 is located at substantially the same position as a part of the second pulley 63 in the cutting direction. In other words, the fourth pulley 67 is located behind the front end of the second pulley 63 and in front of the rear end of the second pulley 63. With such a configuration, it is possible to prevent the size of the electric circular saw 1 in the cutting direction from becoming large.

Further, in the direction of the axis C, at least a part of each of the rotating shaft 51 and the intermediate shaft 62 of the motor 5 is located at a position where it overlaps with the circular saw blade P (see FIG. 1). This makes it possible to suppress an increase in the size of the electric circular saw 1 in the vertical and front-rear directions.

Further, in the present embodiment, in the direction of the axis C, the first line segment (i) connecting the axis A of the rotating axis 51 and the axis B of the intermediate axis 62, and the second line segment connecting the axis B and the axis C. Each of the internal angles in the triangle formed by the minute (ii) and the third line segment (iii) connecting the axis A and the axis C is configured to be 90 degrees or less. Specifically, the angle α formed by the first line segment (i) and the second line segment (ii), the angle β formed by the second line segment (ii) and the third line segment (iii), and the third line. Each of the angles γ formed by the minute (iii) and the first line segment (i) is 90 degrees or less. According to such a configuration, it is possible to prevent the size of the electric circular saw 1 in the cutting direction and the size of the electric circular saw 1 in the vertical direction from becoming large. With the above configuration, the size of the circular saw 1 can be reduced, but since the pulleys are close to each other, the area (contact angle) in the circumferential direction of the pulleys that can contact the belt becomes small. In the embodiment, since the belt used for transmission is a timing belt that transmits by meshing with teeth instead of transmission by friction, it is possible to suitably transmit rotation even with a small contact angle. This effect is particularly remarkable when the fourth pulley 67 is arranged so as to be separated from the first pulley 61 in the front-rear direction and in the vertical direction. In the present embodiment, both the first belt 64 and the second belt 68 are used as timing belts to perform good rotation transmission, but at least one of them may be used as a timing belt. For example, the first belt 64 is a belt that transmits by friction transmission (for example, a V-belt in which a V-shaped groove is formed in the rotational direction), and the first pulley 61 and the second pulley 63 are shaped to correspond to the V-belt. , The second belt 68 may be used as a timing belt. Since the second belt 68 transmits a high torque rotational force after deceleration, a rotational transmission shape such as a timing belt by meshing teeth is suitable.

In the present embodiment, all the internal angles (angles α, β, γ) of the triangle formed by the first line segment (i), the second line segment (ii), and the third line segment (iii) are 90. Although it is configured to be 90 degrees or less, it may be configured so that at least one angle is 90 degrees or less.

Next, the operation in which the rotation of the motor 5 is transmitted to the circular saw blade P will be described.

When the user pulls the switch 33A of the handle portion 33, the motor 5 is activated and the rotating shaft 51 rotates integrally with the first pulley 61. Along with this rotation, the unevenness of the outer peripheral surface of the first pulley and the unevenness of the inner peripheral surface of the first belt 64 bridged over the first pulley 61 mesh with each other, so that the first belt 64 rotates. Along with this rotation, the unevenness of the outer peripheral surface of the second pulley 63 and the unevenness of the inner peripheral surface of the first belt 64 bridged over the second pulley 63 mesh with each other, so that the second pulley 63 is integrated with the intermediate shaft 62. Rotate to. Here, since the second pulley 63 is formed to have a larger diameter than the first pulley 61, the rotation of the rotating shaft 51 is decelerated and transmitted to the intermediate shaft 62. That is, the first-stage transmission mechanism including the first pulley 61, the second pulley 63, and the first belt 64 decelerates the rotation of the rotating shaft 51 and transmits it to the intermediate shaft 62 (second pulley 63).

When the intermediate shaft 62 rotates, the third pulley 65 fixed to the intermediate shaft 62 rotates together with the intermediate shaft 62 and the second pulley 63 at the same rotation speed. Along with this rotation, the unevenness of the outer peripheral surface of the third pulley and the unevenness of the inner peripheral surface of the second belt 68 bridged over the third pulley mesh with each other, so that the second belt 68 rotates. Along with this rotation, the unevenness of the outer peripheral surface of the fourth pulley 67 and the unevenness of the inner peripheral surface of the second belt 68 bridged over the fourth pulley 67 mesh with each other, so that the fourth pulley 67 is integrated with the spindle 66. Rotate. Here, since the fourth pulley is formed to have a diameter larger than that of the third pulley 65, the rotation of the intermediate shaft 62 is decelerated and transmitted to the spindle 66. That is, the second-stage transmission mechanism including the third pulley 65, the fourth pulley 67, and the second belt 68 decelerates the rotation of the intermediate shaft 62 and transmits it to the spindle 66.

In this state, as shown in FIG. 9, even when the first belt 64 tries to move to the right with respect to the first pulley 61 and the second pulley 63, the left surface of the first plate 71 The left surface of the regulating portion 72A of the second plate 72 abuts on the right surface of the first belt 64 in the width direction, and the movement of the first belt 64 to the right is restricted. Further, as shown in FIG. 10, even when the second belt 68 tries to move to the left with respect to the third pulley 65, the right surface of the protruding portion 72B of the second plate 72 is the second belt. It abuts on the left side surface in the width direction of 68 and restricts the movement of the second belt 68 to the left. As a result, the contact between the first belt 64 and the second belt 68 is suppressed, and it is possible to prevent the power transmission unit 6 from being damaged.

When the spindle 66 rotates, the circular saw blade P mounted on the mounting portion 66A of the spindle 66 rotates together with the spindle 66 at the same rotation speed. That is, the rotation of the rotating shaft 51 is decelerated in two stages by the two-stage transmission mechanism and transmitted to the circular saw blade P.

In the present embodiment, the diameter of the fourth pulley 67 is larger than the diameter of the third pulley 65 so that the reduction ratio of the first-stage transmission mechanism is larger than the reduction ratio of the second-stage transmission mechanism. The enlargement ratio of the diameter of the second pulley 63 is smaller than the enlargement ratio of the diameter of the first pulley 61.

Further, since the power transmission unit 6 in the present embodiment decelerates in two stages, it is not necessary to provide the spindle 66 with a pulley having a large diameter. In the present embodiment, a second pulley 63 having a diameter larger than that of the fourth pulley 67 provided on the spindle 66 is provided on the intermediate shaft 62, and the intermediate shaft 62 is separated from the upper surface of the base 2. That is, since the intermediate shaft 62 to which the second pulley 63 having a relatively large diameter is attached is separated from the base 2, it is possible to secure a sufficient cutting depth. More specifically, the intermediate shaft 62 is positioned at a position separated from the base 2 than the rotating shaft 51, that is, above the rotating shaft 51, so that the intermediate shaft 62 is intentionally moved away from the rotation center position of the circular saw blade P. The large-diameter second pulley 63 can be accommodated without increasing the size of 34, and a sufficient reduction ratio can be obtained by the first-stage deceleration. As a result, the diameter of the fourth pulley 67 (final pulley) can be suppressed to the minimum necessary, and the pulley accommodating portion 34 located below the center of the circular saw P can be made smaller to affect the cutting depth. Since it can be made smaller, it is possible to secure a sufficient cutting depth. Further, since the intermediate shaft 62 is located on the opposite side of the rotating shaft 51 in the cutting direction, that is, behind, it is possible to suppress the increase in size of the main body in the cutting direction side and to improve the visibility of the work material in front. It can be secured and the workability can be suppressed from being impaired.

Next, the step of assembling the power transmission unit 6 to the pulley accommodating unit 34 in the electric circular saw 1 according to the first embodiment will be described with reference to FIGS. 13 to 18.

First, as shown in FIG. 13, the rotating shaft 51 of the motor 5 with the first pulley 61, the bearing 34A and the needle bearing 71B attached is inserted into the through hole 341a of the pulley case 341 from the left side. The rotating shaft 51 is supported by the pulley case 341 via a bearing 34A. In this state, the first pulley 61 is located in the transmission mechanism accommodating space 34a.

Next, the intermediate shaft 62 in which the second pulley 63, the third pulley 65, the bearing 34B, and the needle bearing 34C are attached is attached to the pulley case 341 from the right side. Specifically, the left end of the intermediate shaft 62 to which the bearing 34B is attached is fitted to the protrusion 341G, and the left end of the intermediate shaft 62 is fixed to the pulley case 341. In this state, the intermediate shaft 62, the second pulley 63, and the third pulley 65 are located in the transmission mechanism accommodating space 34a.

Next, as shown in FIG. 14, the first belt 64 is stretched between the first pulley 61 and the second pulley 63 from the right side.

Next, as shown in FIG. 15, the first plate 71 in which the needle bearing 71B is fixed to the inner circumference of the cylindrical portion 71A is attached to the second left wall of the pulley case 341 using a plurality of male screws. It is fixed to 341B. Specifically, the first plate 71 is attached to the pulley case 341 from the right side so that the right end portion of the rotating shaft 51 fits into the inner ring of the needle bearing 71B. The left end of the rotating shaft 51 is supported by the cylindrical portion 71A, and the first plate 71 is fixed to the pulley case 341, so that the rotating shaft 51 can be suitably suppressed from tilting in the left-right direction. It becomes.

Next, the second plate 72 is fixed to the right surface of the second pulley 63 using a plurality of male screws. Specifically, the second plate 72 is attached to the pulley case 341 from the right side so that the third pulley 65 is inserted into the insertion hole located at the substantially central portion in the radial direction of the second plate 72.

Next, as shown in FIGS. 10 and 16, the spindle 66 with the fourth pulley 67, the needle bearing 34D, and the bearing 34E attached is attached to the pulley case 341 from the right side. Specifically, the left end of the spindle 66 to which the needle bearing 34D is attached is fitted into the recess 341b of the pulley case 341, and the left end of the spindle 66 is fixed to the left end of the pulley case 341.

Next, as shown in FIG. 17, the second belt 68 is stretched between the third pulley 65 and the fourth pulley 67 from the right side.

Finally, as shown in FIGS. 10 and 18, the pulley cover 342 with the needle bearing 34C fixed to the inner circumference of the protrusion 342A is attached along the contour of the third peripheral wall 341F of the pulley case 341. , Fixed to the third left wall 341C using a plurality of male screws. Specifically, the pulley so that the right end portion of the intermediate shaft 62 fits into the inner ring of the needle bearing 34C and the outer ring of the bearing 34E fixed to the spindle 66 fits into the first cylindrical portion 342B. The cover 342 is attached to the pulley case 341 from the right side. The left end of the intermediate shaft 62 is supported by the protruding portion 342A, and the pulley cover 342 is fixed to the pulley case 341, so that the intermediate shaft 62 can be suitably suppressed from tilting in the left-right direction. Become.

As described above, according to the present embodiment, the contact between the first belt 64 and the second belt 68 can be regulated by providing the belt contact regulating portion 7, so that the motor 5 is mounted on the pulley case 341. It is possible to attach from one side (left side) and attach the first belt 64 and the second belt 68 from the other side (right side) of the pulley case 341. In other words, the second belt 68, the belt contact restricting portion 7, the first belt 64, the first left wall 341A, and the motor main body portion 50 are arranged in this order in the axis C direction of the spindle 66. As a result, both the first belt 64 and the second belt 68 can be arranged in the transmission mechanism accommodating space 34a from one side of the first left wall 341A of the pulley case 341, and the assembling property can be improved. ..

In the present embodiment, the first pulley 61 and the second pulley 63 constituting the first-stage transmission mechanism are timing pulleys, and the first belt 64 is a timing belt, but the first pulley and the second pulley are used. A V pulley may be used, and the first belt may be a V belt. In this case, it is preferable to improve the transmission performance due to friction by increasing the belt contact angle (contact surface with the belt) of the first pulley 61 with a tensioner, an idle pulley, or the like.

Next, the electric circular saw 100, which is an example of the cutting machine according to the second embodiment of the present invention, will be described with reference to FIGS. 19 to 21. The electric circular saw 100 basically has the same configuration as the electric circular saw 1 according to the first embodiment, and the same configuration as the electric circular saw 1 will be described with the same reference number. The different configurations will be mainly described by omitting them as appropriate. Further, with respect to the same configuration as the electric circular saw 1, the same effect as that described in the description of the first embodiment is obtained.

The electric circular saw 100 includes a pulley accommodating portion 134 in place of the pulley accommodating portion 34, and includes a power transmission unit 16 in place of the power transmission unit 6.

The pulley accommodating portion 134 has a pulley case 1341 and a pulley cover 1342. As shown in FIG. 19, in the present embodiment, a transmission mechanism accommodating space 134a recessed to the left of the pulley case 1341 is provided. The outline of the wall forming the transmission mechanism accommodating space 134a has a substantially quadrangular shape.

As shown in FIGS. 19 and 20, the power transmission unit 16 includes a first pulley 161 and a first intermediate shaft 162, a second pulley 163, a first belt 164, and a third pulley 165. It has a second intermediate shaft 166, a fourth pulley 167, a second belt 168, a fifth pulley 169, a spindle 170, a sixth pulley 171 and a third belt 172.

The first pulley 161 is a timing pulley, and has the same configuration as the first pulley 61 of the electric circular saw 1 in the first embodiment. The first pulley 161 is an example of the "first pulley" in the present invention.

As shown in FIG. 20, the first intermediate shaft 162 has a substantially cylindrical shape and is arranged so as to extend in the left-right direction in parallel with the rotation shaft 51. The first intermediate shaft 162 is rotatably supported by the pulley accommodating portion 134 via a plurality of bearings. The first intermediate shaft 162 rotates about an axis D extending in the left-right direction. The first intermediate shaft 162 is an example of the "first intermediate shaft" and the "driven shaft" in the present invention.

The second pulley 163 is a timing pulley and has an outer diameter larger than the outer diameter of the first pulley 161. Further, the second pulley 163 has an outer diameter smaller than that of the second pulley 63 of the electric circular saw 1 in the first embodiment. The second pulley 163 is fixed by press fitting to the left side of the central portion of the first intermediate shaft 162, and rotates about the axis D integrally with the first intermediate shaft 162. The second pulley 163 is an example of the "second pulley" in the present invention. The axis D is an example of the "axis of the first intermediate axis" in the present invention.

The first belt 164 is a timing belt and is stretched between the first pulley 161 and the second pulley 163. The first belt 164 is an example of the "first belt" in the present invention.

The third pulley 165 is a timing pulley and has an outer diameter smaller than that of the second pulley 163. The third pulley 165 is fixed by press fitting to the right side of the central portion of the first intermediate shaft 162, and rotates about the axis D integrally with the first intermediate shaft 162. The third pulley 165 is an example of the "third pulley" in the present invention.

The second intermediate shaft 166 has a substantially cylindrical shape, and is arranged so as to extend in the left-right direction in parallel with the rotating shaft 51 and the first intermediate shaft 162. The second intermediate shaft 166 is rotatably supported by the pulley accommodating portion 134 via a plurality of bearings. The first intermediate shaft 162 rotates about an axis E extending in the left-right direction. The second intermediate shaft 166 is an example of the "second intermediate shaft" in the present invention.

The fourth pulley 167 is a timing pulley and has an outer diameter larger than the outer diameter of the third pulley 165. Further, the fourth pulley 167 has an outer diameter smaller than that of the second pulley 63 of the electric circular saw 1 in the first embodiment. The fourth pulley 167 is fixed by press fitting to the left side of the central portion of the second intermediate shaft 166, and rotates about the axis E integrally with the second intermediate shaft 166. The fourth pulley 167 is an example of the "fourth pulley" in the present invention. The axis E is an example of the "axis of the second intermediate axis" in the present invention.

The second belt 168 is a timing belt and is stretched between the third pulley 165 and the fourth pulley 167. The second belt 168 is an example of the "second belt" in the present invention.

The fifth pulley 169 is a timing pulley and has an outer diameter smaller than that of the fourth pulley 167. The fifth pulley 169 is fixed by press fitting to the right side of the central portion of the second intermediate shaft 166, and rotates about the axis E integrally with the second intermediate shaft 166. The fifth pulley 169 is an example of the "fifth pulley" in the present invention.

The spindle 170 extends in the left-right direction and is configured to be the same as the spindle 66 of the electric circular saw 1 in the first embodiment. The spindle 170 is an example of the "output shaft" in the present invention.

The sixth pulley 171 is a timing pulley, and has the same configuration as the fourth pulley 67 of the electric circular saw 1 in the first embodiment. The sixth pulley 171 is an example of the "sixth pulley" in the present invention.

The third belt 172 is a timing belt and is stretched between the third pulley 165 and the fourth pulley 167. The third belt 172 is an example of the "third belt" in the present invention.

In the present embodiment, as shown in FIG. 19, at least a part of the first pulley 161 is located at substantially the same position as at least a part of the fourth pulley 167 in the vertical direction. In other words, at least a part of the first pulley 161 is located at substantially the same position as the fourth pulley 167 in the direction orthogonal to the axis C direction and the front-rear direction (cutting direction) of the spindle 170. In the present embodiment, substantially all of the first pulley 161 is located at substantially the same position as a part of the fourth pulley 167 in the vertical direction. According to such a configuration, it is possible to prevent the size of the electric circular saw 100 from becoming large in the direction orthogonal to the axis C direction and the cutting direction of the spindle 170.

Further, at least a part of the second pulley 163 is located at substantially the same position as a part of the sixth pulley 171 in the front-rear direction. In other words, at least a part of the second pulley 163 is located at substantially the same position as at least a part of the sixth pulley 171 in the cutting direction. In the present embodiment, substantially all of the sixth pulley 171 is located at substantially the same position as a part of the second pulley 163 in the cutting direction. With such a configuration, it is possible to prevent the size of the electric circular saw 100 in the cutting direction from becoming large.

Further, in the axial view of the axis C, at least a part of each of the rotating shaft 51, the first intermediate shaft 162, the second intermediate shaft 166, and the spindle 170 of the motor 5 is located at a position where it overlaps with the circular saw blade P. This makes it possible to suppress an increase in the size of the electric circular saw 100 in the vertical direction and the front-rear direction.

Further, in the present embodiment, since the deceleration is performed in three stages, the outer diameters of the second pulley 163 and the fourth pulley 167 can be reduced, and the size of the electric circular saw 100 in the vertical direction and the cutting direction can be increased. It can be kept small.

In the present embodiment, the electric circular saws 1 and 100 have been described as examples of the cutting machine, but the present invention can also be applied to a power tool driven by a motor other than the electric circular saw, for example, a cutting machine such as a chainsaw. Is. From the viewpoint of assembleability, it is preferable that the belt can be stretched from one direction even with other power tools.

1 ... Electric circular saw, 2 ... Base, 3 ... Housing, 4 ... Cutting depth adjustment mechanism, 5 ... Motor, 6 ... Power transmission unit, 7 ... Belt contact regulation part

Claims (14)

With the housing
A motor supported by the housing and having a rotating shaft,
A first pulley provided on the rotating shaft and rotating integrally with the rotating shaft,
A second pulley formed with a diameter larger than that of the first pulley,
A first belt stretched between the first pulley and the second pulley and transmitting the rotation of the first pulley to the second pulley,
An intermediate shaft supported by the housing and supporting the second pulley,
A third pulley provided on the intermediate shaft, formed to have a diameter smaller than that of the second pulley, and integrally rotating with the second pulley about the axis of the intermediate shaft.
An output shaft rotatably supported by the housing,
A fourth pulley provided on the output shaft, which has a diameter larger than that of the third pulley and a diameter smaller than that of the second pulley and rotates integrally with the output shaft.
A second belt stretched between the third pulley and the fourth pulley and transmitting the rotation of the third pulley to the fourth pulley,
It is equipped with a circular cutting blade that can be mounted on the output shaft and that rotates by transmitting the rotation of the fourth pulley.
By moving the cutting blade in the cutting direction, it is possible to cut the work material.
At least a part of the second pulley is located at the same position as at least a part of the fourth pulley in the cutting direction, and a portion located outside the outer diameter of the cutting blade in the axial view of the motor. Have and
The third pulley is a cutting machine characterized in that it is located within the outer diameter of the cutting blade in the axial direction of the motor . The cutting according to claim 1 , wherein at least a part of the first pulley is at the same position as at least a part of the second pulley in the axial direction of the output shaft and the direction orthogonal to the cutting direction. Machine. The cutting machine according to claim 1 or 2, wherein each of the rotation center of the first pulley and the rotation center of the second pulley are located at positions overlapping with the cutting blade in the axial view. .. It also has a base that supports the housing and moves it in the cutting direction on the work piece to cut the work piece.
The cutting machine according to any one of claims 1 to 3, wherein the rotation center of the second pulley is located at a position away from the base from the rotation axis. In the axial view, the first line segment connecting the axis of the rotating axis and the axis of the intermediate axis, the second line segment connecting the axis of the intermediate axis and the axis of the output axis, and the rotating axis. 2. Claim 2 characterized in that the internal angle formed by the first line segment and the second line segment in a triangle formed by the third line segment connecting the axis and the axis of the output shaft is 90 degrees or less. The cutting machine described in. The cutting machine according to claim 5, wherein the internal angle formed by the second line segment and the third line segment in the triangle is 90 degrees or less. The cutting machine according to claim 5 or 6, wherein each of the internal angles in the triangle is 90 degrees or less. A gear case having a wall portion that is recessed in the axial direction of the output shaft and forms a recess for accommodating the first belt and the second belt.
It also has a regulatory wall that regulates contact between the first belt and the second belt.
The motor further has a motor body portion.
The cutting machine according to any one of claims 1 to 7, wherein the second belt, the regulation wall, the first belt, the wall portion, and the motor main body portion are arranged in this order in the axial direction. The first belt and the second belt are timing belts, and the first pulley, the second pulley, the third pulley and the fourth pulley are timing pulleys. The cutting machine according to any one of 8. With the housing
A motor supported by the housing and having a rotating shaft,
A first pulley provided on the rotating shaft and rotating integrally with the rotating shaft,
A driven shaft supported by the housing and
A second pulley provided on the driven shaft and rotating around the axis of the driven shaft to have a diameter larger than that of the first pulley.
A first belt stretched over the first pulley and the second pulley and transmitting the rotation of the first pulley to the second pulley,
A third pulley that rotates integrally with the second pulley,
The fourth pulley to which the rotational force of the third pulley is transmitted, and
It has a third pulley and a second belt stretched on the fourth pulley.
A cutting blade that rotates by transmitting the rotational force of the fourth pulley,
It has a base that supports the housing and has a hole for projecting a part of the cutting blade downward.
By moving the cutting blade in the cutting direction, it is possible to cut the work material.
The center of rotation of the first pulley is positioned within the outer diameter of the cutting blade when viewed in the axial direction of the motor.
The center of rotation of the cutting blade is positioned within the outer diameter of the cutting blade and below the center of rotation of the first pulley when viewed in the axial direction of the motor .
Cutting machine, wherein the center of rotation of the second pulley, said outer diameter of the cutting blade, and is positioned above the center of rotation of said first pulley when viewed in the axial direction of the motor. The cutting machine according to claim 10 , wherein at least a part of each of the rotating shaft and the driven shaft is located at a position overlapping the cutting blade in the axial view. The claim is characterized in that the first pulley is located above the lower end of the second pulley and below the upper end when the axial direction of the rotation axis and the direction orthogonal to the cutting direction are vertical directions. The cutting machine according to 1 or 10. The cutting machine according to claim 1 or 12 , wherein the fourth pulley is located behind the front end of the second pulley and in front of the rear end when the cutting direction is the front-rear direction. The cutting machine according to claim 12 or 13 , wherein the first belt is a timing belt.

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