WO2019187949A1

WO2019187949A1 - Cutter

Info

Publication number: WO2019187949A1
Application number: PCT/JP2019/007766
Authority: WO
Inventors: 村上　卓宏; 大平野
Original assignee: 工機ホールディングス株式会社
Priority date: 2018-03-30
Filing date: 2019-02-28
Publication date: 2019-10-03
Also published as: JP6822605B2; DE212019000237U1; JPWO2019187949A1; CN214561574U

Abstract

In order to provide a cutter which is capable of improving assemblability while suppressing an increase in size of the cutter main body, the present invention is provided with: a first pulley 61 that integrally rotates with a rotary shaft 51; a second pulley 63 that rotates around an axis B of an intermediate shaft 62 and is formed in a larger diameter than the first pulley 61; a first belt 64 that transmits the rotation of the first pulley 61 to the second pulley 63; a third pulley 65 that rotates around the axis B of the intermediate shaft 62, is formed in a smaller diameter than the second pulley 63, and integrally rotates with the second pulley 63; a fourth pulley 67 that is formed in a larger diameter than the third pulley 65 and a smaller diameter than the second pulley 63 and integrally rotates with a spindle 66; and a second belt 68 that transmits the rotation of the third pulley 65 to the fourth pulley 67, wherein at least a portion of the first pulley 61 is located at the same position as at least a portion of the second pulley 63 in the direction of an axis C of the spindle 66 and in a direction perpendicular to the cutting direction.

Description

Cutting machine

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 that transmits the rotational force of the motor to the output shaft, and the rotational force of the motor is transmitted by meshing the gears. An electric circular saw 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 the metal gear, so that noise due to the meshing of the gear may occur.

In order to cope with such a situation, a configuration for transmitting a rotational force using a belt has been proposed.

JP 2011-011283 A

However, compared to the conventional gear meshing method, the belt transmission method requires a distance between the pulleys. Therefore, when the belt transmission method is adopted in the electric circular saw as described above, the main body of the cutting machine is There is a risk of increasing the size. In addition, if a pulley with a large diameter is attached to the output shaft, the cutting depth may decrease. Therefore, when the motor rotation is decelerated and transmitted to the output shaft, multiple belts are provided. Although it is necessary to set it as the structure which decelerates in a stage, there exists a possibility that a cutting machine main body may enlarge more and the assembly may become difficult.

Therefore, an object of the present invention is to suppress an increase in the size of a cutting machine body having high silence. Another object of the present invention is to provide a cutting machine capable of improving the assemblability.

In order to solve the above problems, the present invention provides a housing, a motor supported by the housing and having a rotation shaft, a first pulley provided on the rotation shaft and rotating integrally with the rotation shaft, and the first pulley. A second pulley having a larger diameter than 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, and the second pulley A cutting blade that is rotated by transmission of rotation of the pulley, and the workpiece can be cut by moving the cutting blade in a cutting direction, and at least a part of the first pulley includes A cutting machine is provided that is in the same position as at least a part of the second pulley in an axial direction of an output shaft and a direction orthogonal to the cutting direction.

According to the said structure, it becomes possible to suppress that the size of the cutting machine in the direction orthogonal to the axial direction and cutting direction of an output shaft becomes large.

An intermediate shaft that is supported by the housing and supports the second pulley, and is provided on the intermediate shaft, rotates about the axis and has a smaller diameter than the second pulley, and rotates integrally with the second pulley. A third pulley, an output shaft that is rotatably supported by the housing and on which the cutting blade can be mounted, and is provided on the output shaft and has a larger diameter than the third pulley and a smaller diameter than the second pulley. A fourth pulley formed and rotated integrally with the output shaft, and a second belt stretched between the third pulley and the fourth pulley and transmitting 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.

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

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

According to such a configuration, when the output shaft is viewed in the axial direction, the rotating shaft and the intermediate shaft are arranged such that at least a part of the rotating shaft and the side surface of the cutting blade overlap with each other, so that the size of the cutting machine is increased. It becomes possible to suppress.

In addition, when viewed in the axial direction, a first line segment connecting the axis of the rotary shaft and the axis of the intermediate shaft, a second line segment connecting the axis of the intermediate shaft and the axis of the output shaft, and the rotation It is preferable that an interior angle formed by the first line segment and the second line segment in a triangle formed by a third line segment connecting the axis line of the shaft and the axis line of the output shaft is 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 direction orthogonal to the axial direction of the output shaft and the cutting direction.

Moreover, it is preferable that the interior angle made by the second line segment and the third line segment in the triangle is 90 degrees or less.

Each of the interior 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 direction orthogonal to the axial direction and the cutting direction of the output shaft.

A base that supports the housing and moves in the cutting direction on the workpiece in order to cut the workpiece; and the intermediate shaft is located at a position farther 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 ensure a sufficient cutting depth.

Also, a pulley case having a wall portion that is recessed in the axial direction of the output shaft and that forms a recess that accommodates the first belt and the second belt, and a restriction wall that restricts contact between the first belt and the second belt. Preferably, the motor further includes a motor main body, and the second belt, the regulation wall, the first belt, the wall, and the motor main body are arranged in the axial direction in this order.

According to such a configuration, since the regulation wall regulates contact between the first belt and the second belt, both the first belt and the second belt are disposed in the recess from one side of the wall portion of the pulley case. Is possible. Thereby, it becomes possible to improve assembly property.

Preferably, 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.

According to such a configuration, even when a heavy load is generated on the cutting blade, the occurrence of rattling or the like is suppressed, so that an efficient and stable cutting operation can be performed. In addition, the use of the timing belt and timing pulley improves the rotation transmission efficiency compared to the friction transmission type belt and suppresses belt slippage. Is improved.

The present invention further includes 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, a driven shaft supported by the housing, A second pulley provided on the driven shaft, rotated about the axis of the driven shaft and having a larger diameter than the first pulley; and stretched between the first pulley and the second pulley; A first belt that transmits the rotation of one pulley to the second pulley, a cutting blade that rotates when the rotational force of the second pulley is transmitted, the housing is supported, and a part of the cutting blade protrudes downward And a base having a hole for causing the cutting blade to have a rotation center positioned below the rotation center, and the second pulley rotation center positioned above the first pulley rotation center. Cutting machine characterized by It has to offer.

According to the above configuration, the position of the second pulley is intentionally moved away from the rotation center of the cutting blade, thereby facilitating the arrangement of the large second pulley and suppressing the increase in the size of the cutting machine. It becomes possible.

A third pulley that rotates integrally with the second pulley; a fourth pulley to which a rotational force of the third pulley is transmitted; a second belt stretched between the third pulley and the fourth pulley; Preferably, the rotation center of the fourth pulley is at a position below the rotation center of the second pulley.

Moreover, it is preferable that 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 direction view.

According to such a configuration, when the output shaft is viewed in the axial direction, the rotating shaft, the first intermediate shaft, and the second intermediate shaft are arranged so that at least a part thereof overlaps the side surface of the cutting blade. Can be prevented from increasing in size.

The first pulley is preferably located above the lower end of the second pulley and below the upper end when the direction perpendicular to the axial direction of the output shaft and the cutting direction is the vertical direction.

In addition, when the cutting direction is the front-rear direction, the fourth pulley is preferably positioned behind the front end of the second pulley and ahead of the rear end.

The first belt is preferably a timing belt.

According to the cutting machine of this invention, it can suppress that a cutting machine main body enlarges. In addition, it is possible to improve assemblability while ensuring quietness.

It is a right view which shows the external appearance of the electric circular saw concerning the 1st Embodiment of this invention. (A) is a top view of the electric circular saw concerning the 1st Embodiment of this invention, and a partial cross section is shown. (B) is a right side view showing the cut depth adjusting mechanism of the base of the electric circular saw according to the first embodiment of the present invention. It is a left view which shows the external appearance of the electric circular saw concerning the 1st Embodiment of this invention, and the partial cross section of the handle | steering-wheel part is shown. It is an enlarged view of the cutting depth adjusting mechanism of the electric circular saw according to the first embodiment of the present invention. It is a perspective view which shows the state in which the 1st step | paragraph transmission mechanism of the electric circular saw concerning the 1st Embodiment of this invention is accommodated in the pulley accommodating part. It is a perspective view which shows the state in which the power transmission part and belt contact control part of the electric circular saw concerning the 1st Embodiment of this invention are accommodated in the pulley accommodating part. It is a perspective view which shows the external appearance of the pulley accommodating part of the electric circular saw concerning the 1st Embodiment of this invention. It is a schematic diagram which shows the positional relationship of a motor shaft, an intermediate shaft, and a spindle in the right side view. FIG. 9 is a sectional view taken along line IX-IX in FIG. 8. FIG. 9 is a sectional view taken along line XX in FIG. 8. It is sectional drawing which passes along the axis line of the intermediate shaft of the electric circular saw concerning the 1st Embodiment of this invention, and is parallel to the axis line of an intermediate shaft. It is a right view which shows the positional relationship of the motor shaft of the electric circular saw concerning the 1st Embodiment of this invention, an intermediate shaft, and a spindle. It is FIG. (1) explaining the assembly | attachment process to the pulley case of the power transmission part of the electric circular saw concerning the 1st Embodiment of this invention. It is FIG. (2) explaining the assembly | attachment process to the pulley case of the power transmission part of the electric circular saw concerning the 1st Embodiment of this invention. It is FIG. (3) explaining the assembly | attachment process to the pulley case of the power transmission part of the electric circular saw concerning the 1st Embodiment of this invention. It is FIG. (4) explaining the assembly | attachment process to the pulley case of the power transmission part of the electric circular saw concerning the 1st Embodiment of this invention. It is FIG. (5) explaining the assembly | attachment process to the pulley case of the power transmission part of the electric circular saw concerning the 1st Embodiment of this invention. It is FIG. (6) explaining the assembly | attachment process to the pulley case of the power transmission part of the electric circular saw concerning the 1st Embodiment of this invention. It is a right view which shows the positional relationship of the motor shaft of the electric circular saw concerning the 2nd Embodiment of this invention, a 1st intermediate shaft, a 2nd intermediate shaft, and a spindle. It is sectional drawing which passes along each axis of a motor shaft, a 1st intermediate shaft, a 2nd intermediate shaft, and a spindle in the power transmission part of the electric circular saw concerning the 2nd Embodiment of this invention. It is a figure explaining the effect of the electric circular saw concerning 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. The electric circular saw 1 is an electric tool for cutting a material to be cut such as wood using a circular saw blade P.

In the following description, “front” shown in the figure is defined as the front direction, “rear” is defined as the rear direction, “upper” is defined as the upper direction, and “lower” is defined as the lower direction. 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. References to dimensions, numerical values, and the like in this specification include not only dimensions and numerical values that completely match the relevant dimensions and numerical values, but also substantially identical dimensions and numerical values (for example, within the range of manufacturing errors). ). Similarly, “same”, “perpendicular”, “parallel”, “match”, “same”, “substantially same”, “substantially orthogonal”, “substantially parallel”, “substantially match”, “substantially flush” Etc.

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 regulating unit 7. is doing.

As shown in FIGS. 1 to 3, the base 2 supports a housing 3. The base 2 is made of a metal such as aluminum, for example, and extends in the front-rear direction and has a substantially rectangular shape in bottom view. A long hole 2 A that extends in the front-rear direction and allows the circular saw blade P to enter is formed at the center in the left-right direction of the base 2. The circular saw blade P extends downward from the upper side through the long hole 2A. The length of the circular saw blade P that protrudes downward from the bottom surface of the base 2 is the cutting depth. The long hole 2A is an example of the “hole” in the present invention. The longitudinal direction of the base 2 coincides with the cutting direction when the electric circular saw 1 performs the cutting operation, that is, the front-rear direction. The bottom surface of the base 2 is a sliding surface that is slid with respect to the material to be cut during a cutting operation. 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 in the cutting direction on the cutting material in order to cut the material to be cut during the work. It is possible. As shown in FIGS. 1 and 2, the base 2 has a housing rotation support portion 21 and a shaft 22. The base 2 is an example of the “base” in the present invention. The material to be cut is an example of the “work material” in the present invention. The front-rear 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 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 an outline 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. 36 is comprised. As shown in FIG. 2, from the left rear portion of the housing 3, a power cord 3 A having a plug portion that can be connected to a commercial AC power source extends leftward. The power cord 3A is electrically connected to the motor 5 inside the housing 3, and the power can be supplied to the motor 5 by connecting the plug portion of the power cord 3A to a commercial AC power source. The housing 3 is an example of the “housing” in the present invention.

The motor housing 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 housing portion 31 A houses the motor 5.

As shown in FIGS. 1 to 3, the handle portion 33 extends in the front-rear direction above the motor housing portion 31. The handle portion 33 is a portion that is held by an operator during cutting work. The handle portion 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. The pulley accommodating portion 34 is made of, for example, metal and accommodates the power transmission portion 6. is doing. The pulley housing portion 34 is provided with a rotation restricting member 3C. Although not shown in the drawing, an engagement portion having a substantially U-shape in 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 extends 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 the pulley accommodating portion 34. The saw cover 35 covers the upper part of the circular saw blade P. The saw cover 35 may be formed of the same material as that of the pulley housing portion 34 and may be integrally formed. A shaft 22 provided on the upper portion of 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. By rotating the saw cover 35 around the shaft 22 with respect to the base 2, the motor accommodating portion 31, the substrate accommodating portion 32, the handle portion 33, the pulley accommodating portion 34, the saw cover 35, and the protective cover 36 (housing 3) 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. A biasing 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 to cover the lower side of the circular saw blade P. Thereby, the protective cover 36 covers a part of the lower part of the circular saw blade P in a state where the cutting operation is not performed.

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

As shown in FIG. 2B, the lower end of the link portion 41 is fixed to the upper surface of the base 2 with a screw. 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 part 41 is formed in a substantially quadrant (quarter circle) shape. The link portion 41 is formed with a circular arc groove 41 a that extends upward along the link portion 41. The link portion 41 has one end portion 41 A located at a position closest to the base 2 and another end portion 41 B located at a position farthest from the base 2. A pressing surface 41 C 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 through the arc groove 41 a of the link portion 41. In the present embodiment, the attitude of the housing 3 with respect to the base 2 changes as the shaft 43 moves along the arc groove 41a. In other words, the link portion 41 is configured to guide 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 is configured to be able to change the relative position with respect to the base 2. 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, when the shaft 43 moves downward along the arc groove 41a, it can come into contact with the 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 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 the one end portion 41A and the other end portion 41B.

The restricting portion 42 includes 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 configured integrally with the base portion 42A. That is, the saw cover 35 is rotatably supported. The lever portion 42B is rotated about an axis extending in the left-right direction when operated by an operator.

The cam 42 C has a tubular shape and is substantially elliptical in side view. A base 42A is fitted to the inner peripheral surface of the cam 42C. Thereby, the cam 42C can rotate integrally with the lever portion 42B.

The shaft 42 D 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 larger than the outer diameter of the shaft 42D, and the pressing member 42E is configured to be movable in the up / down and front / rear directions with respect to the shaft 42D. In other words, the pressing member 42E is configured to engage (play together) with the shaft 42D with play and be movable 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. For this reason, the lever portion 42B rotates in the clockwise direction in FIG. 4 (the arrow X direction in FIG. 4), so that the long axis direction of the cam 42C is substantially orthogonal to the pressing surface 41C of the link portion 41. 6 rotates in the clockwise direction of FIG. 6, and the pressing member 42E moves in a direction approaching the pressing surface 41C as the cam 42C rotates, 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 of the cam 42C is substantially parallel to the pressing surface 41C of the link portion 41, the pressing member 42E moves away from the pressing surface 41C, and the outer periphery 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 50 is located on the left side of the pulley accommodating portion 34. The motor 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 supported by the housing 3 via a bearing so as to be rotatable about an axis A extending in the left-right direction. The rotating shaft 51 is provided with an engaged portion 51A in which two surfaces parallel to the left-right direction and parallel to each other are formed. In the present embodiment, the operator presses the rotation restricting member 3C toward the inside of the pulley accommodating portion 34 against the urging force of the urging member (not shown), and the rotation restricting member 3C is not shown. It is possible to regulate the rotation of the rotating shaft 51 by engaging the non-engaging portion with the engaged portion 51A. By restricting the rotation of the rotating shaft 51, the rotation of the circular saw blade P can be restricted via the power transmission unit 6, and the circular saw blade P can be preferably exchanged. The rotating shaft 51 is an example of the “rotating shaft” in the present invention. 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 rotatable integrally with the rotating shaft 51.

Next, the detailed structure of the pulley accommodating part 34, the power transmission part 6, and the belt contact control part 7 is demonstrated.

As shown in FIGS. 5 to 7, the pulley accommodating portion 34 has a substantially semicircular shape in the left and 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. And the fourth left wall 341S. The pulley case 341 is an example of the “pulley case” in the present invention.

The first left wall 341A extends in the up / down and front / rear directions. As shown in FIG. 9, a through hole 341a is formed in the front part of the first left wall 341A, and a protrusion 341G is provided in the rear part 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 rightward from the right surface of the first left wall 341A and has a substantially circular shape when viewed from the right. A bearing 34B is fitted to the inner peripheral surface of the protrusion 341G.

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

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

As shown in FIG. 5, the third left wall 341C extends in the vertical direction 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 leftward from the right surface of the third left wall.

The fourth left wall 341S extends in the vertical direction and is located on the right side 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 rightward so as to connect the right surface of the first left wall 341A and the right surface 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 rightward so as to connect the right surface of the second left wall 341B and the right surface of the third left wall 341C. The first peripheral wall 341 D and the second peripheral wall 341 E are formed so that the inner peripheral surface at the upper part is flush with each other and curved with a predetermined curvature.

The third peripheral wall 341F extends rightward 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 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. The pulley case 341 is fixed. The pulley cover 342 includes 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 342 A has a bottomed cylindrical shape protruding rightward from the right surface of the pulley cover 342. A needle bearing 34C is fitted to the protrusion 342A.

The first cylindrical portion 342 B has a cylindrical shape that protrudes rightward from the right surface of the pulley cover 342. 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 rightward from the right surface of the first cylindrical portion 342B. The inner diameter of the second cylindrical portion 342C is smaller than the inner diameter of the first cylindrical portion 342B.

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

As shown in FIGS. 5 and 6, the power transmission unit 6 is a part that transmits the rotation of the motor 5 to the circular saw blade P by a two-stage belt system, and includes a first pulley 61, an

intermediate shaft

62, 2 pulley 63, first belt 64, third pulley 65, spindle 66, fourth pulley 67 and second belt 68. Among these, the 1st pulley 61, the 2nd pulley 63, and the 1st belt 64 comprise the 1st stage transmission mechanism, and the 3rd pulley 65, the 4th pulley 67, and the 2nd belt 68 are the 2nd stage. Configure the transmission mechanism. The first-stage transmission mechanism and the second-stage transmission mechanism are accommodated in the transmission mechanism accommodation space 34a.

The first pulley 61 is a timing pulley, has a substantially cylindrical shape extending in the left-right direction, and has gear-shaped irregularities 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 341 A 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 disposed so as to extend in the left-right direction in parallel with the rotation shaft 51. As shown in FIG. 9, the intermediate shaft 62 is rotatably supported on the pulley case 341 via a bearing 34B and is rotatably supported on the pulley cover 342 via a needle bearing 34C. The intermediate shaft 62 rotates around 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, has a substantially cylindrical shape extending in the left-right direction, and has gear-shaped irregularities formed on the outer peripheral surface. The second pulley 63 has an outer diameter that is larger than the outer diameter of the first pulley 61. The second pulley 63 is fixed to the left side of the center portion of the intermediate shaft 62 by press fitting, and rotates around the axis B integrally with the intermediate shaft 62. The second pulley 63 has a plurality of female screw holes 63a extending leftward from the right surface. 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 shaft” and “the center of rotation of the second pulley” in the present invention.

The first belt 64 is a resin 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 first belt 64 is stretched between the first pulley 61 and the second pulley 63 by bridging the front part of the first belt 64 on the outer circumference of the first pulley 61 and the rear part of the first belt 64 on 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 gear-shaped irregularities formed on the outer peripheral surface. The third pulley 65 has an outer diameter that is smaller than the outer diameter of the second pulley 63. The third pulley 65 is fixed to the right side of the center portion of the intermediate shaft 62 by press-fitting, 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 disposed so as to extend in the left-right direction parallel to the rotation shaft 51 and the intermediate shaft 62, and is rotatably supported by the pulley case 341 via the needle bearing 34D. The pulley cover 342 is rotatably supported via the bearing 34E (see FIG. 10). The spindle 66 rotates around an axis C that extends in the left-right direction. A mounting portion 66 A for mounting the circular saw blade P is provided on the right end portion of the spindle 66. The mounting portion 66A protrudes 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, has a substantially cylindrical shape extending in the left-right direction, and has gear-shaped irregularities 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 a smaller outer diameter than the second pulley 63. The fourth pulley 67 is fixed to the left side of the center portion of the spindle 66 by press fitting, and rotates around the axis C together with the spindle 66. The fourth pulley 67 is an example of the “fourth pulley” in the present invention. 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 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 part of the second belt 68 on the outer circumference of the third pulley 65 and bridging the lower part of the second belt 68 on 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 supported so as to be rotatable 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, occurrence of rattling or the like is suppressed, so that an efficient and stable cutting operation 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 portion 7 shown in FIG. 6 is configured to restrict the first belt 64 and the second belt 68 from contacting each other, and includes a first plate 71 and a second plate 72. Yes. The belt contact restricting portion 7 is an example of the “regulating wall” in the present invention.

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

The cylindrical portion 71 A has a bottomed cylindrical shape extending rightward from the right surface of the first plate 71. 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 a needle bearing 71B. Since the rotation shaft 51 is supported by the cylindrical portion 71A and the first plate 71 is fixed to the pulley case 341, it is possible to suitably suppress the rotation shaft 51 from being inclined with respect to the left-right direction.

The second plate 72 shown in FIG. 6 has a substantially disc shape, and the second plate 72 has a plurality of female screw holes 72a. The second plate 72 is fixed to the second pulley 63 from the right side using a plurality of male screws. As shown in FIGS. 9 and 10, the second plate 72 has a restricting portion 72 A and a protruding portion 72 B. 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 restricting portion 72 A forms an outer edge portion of the second plate 72 and is provided so as to prevent the first belt 64 from falling off the second pulley 63. The outer diameter of the restricting portion 72 A is 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 portions of the second plate 72. In the present embodiment, as shown in FIG. 11, the protrusion 72 B protrudes to the right by the width D 1 from the other part of the second plate 72. Accordingly, 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 are in contact with each other. The contact area (see D2 in the figure) between the (left surface) and the right surface of the second plate 72 can be reduced. According to such a configuration, it is possible to suppress breakage of the second belt 68 due to frictional heat or the like generated by contact between the second belt 68 and the second plate 72.

In the present embodiment, by providing the belt contact restricting portion 7, the first belt 64 and the second belt 68 can be arranged so as to overlap each other when viewed from the front.

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 a direction orthogonal to the axis C direction of the spindle 66 and the front-rear direction (cutting direction). 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 suppress an increase in the size of the electric circular saw 1 in the direction (vertical direction) orthogonal to the axis C direction of the spindle 66 and the cutting direction.

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 ahead of the rear end of the second pulley 63. According to such a configuration, it is possible to suppress an increase in the size of the electric circular saw 1 in the cutting direction.

Further, when viewed 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 the circular saw blade P (see FIG. 1). Thereby, it becomes possible to suppress the increase in the size of the electric circular saw 1 in the vertical and front-rear directions.

In the present embodiment, the first line segment (i) connecting the axis A of the rotary shaft 51 and the axis B of the intermediate shaft 62 and the second line connecting the axis B and the axis C as viewed in the direction of the axis C. Each of the interior 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 suppress an increase in 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. With the above configuration, the size of the circular saw 1 can be reduced, but since the pulleys are close to each other, the circumferential area (contact angle) of the pulley that can contact the belt is reduced. In the embodiment, the belt used for transmission is a timing belt that is transmitted by engagement with teeth, not by friction, so that rotation can be suitably transmitted even with a small contact angle. This effect is particularly noticeable when the fourth pulley 67 is spaced from the first pulley 61 in the longitudinal and vertical directions. In the present embodiment, both the first belt 64 and the second belt 68 are used as timing belts for good rotation transmission, but at least one of them may be used as a timing belt. For example, the first pulley 61 and the second pulley 63 have a shape corresponding to the V belt while the first belt 64 is a belt that performs transmission by friction transmission (for example, a V belt in which a V-shaped groove is formed in the rotation direction). The second belt 68 may be a timing belt. Since the second belt 68 transmits a high torque rotational force after deceleration, a rotation transmission shape based on meshing of teeth like a timing belt is suitable.

In the present embodiment, all of the interior 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 less than or equal to degrees, at least one angle may be configured to be 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 33 A 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 meshes with the unevenness of the inner peripheral surface of the first belt 64 spanned by the first pulley 61, whereby the first belt 64 rotates. Along with this rotation, the unevenness on the outer peripheral surface of the second pulley 63 meshes with the unevenness on the inner peripheral surface of the first belt 64 spanned over the second pulley 63, 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 rotation 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 rotation 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 with the intermediate shaft 62 and the second pulley 63 at the same rotational 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 spanned by the third pulley mesh with each other, whereby the second belt 68 rotates. Along with this rotation, the unevenness on the outer peripheral surface of the fourth pulley 67 meshes with the unevenness on the inner peripheral surface of the second belt 68 spanned over the fourth pulley 67, so that the fourth pulley 67 is integrated with the spindle 66. Rotate. Here, since the fourth pulley has a larger diameter than 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 restricting portion 72A of the second plate 72 abuts on the right side surface in the width direction of the first belt 64, and restricts the movement of the first belt 64 to the right. 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. 68 abuts on the left side surface in the width direction and restricts the left belt 68 from moving to the left. Thereby, contact with the 1st belt 64 and the 2nd belt 68 is suppressed, and it becomes possible to control that power transmission part 6 is damaged.

When the spindle 66 rotates, the circular saw blade P mounted on the mounting portion 66A of the spindle 66 rotates with the spindle 66 at the same rotational 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 relative to the diameter of the third pulley 65 is such that the reduction ratio of the first-stage transmission mechanism is larger than the reduction ratio of the second-stage transmission mechanism. Is made smaller than the enlargement ratio of the diameter of the second pulley 63 with respect to the diameter of the first pulley 61.

In addition, since the power transmission unit 6 in this embodiment performs deceleration in two stages, it is not necessary to provide a pulley with a large diameter on the spindle 66. In the present embodiment, a second pulley 63 having a larger diameter than 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 ensure a sufficient cutting depth. More specifically, the intermediate shaft 62 is positioned farther from the base 2 than the rotation shaft 51, that is, above the rotation shaft 51, so as to move away from the rotation center position of the circular saw blade P. The second pulley 63 having a large diameter can be accommodated without increasing the size of 34, and a sufficient reduction ratio can be obtained by the first-stage reduction. As a result, the diameter dimension of the fourth pulley 67 (final pulley) can be minimized, and the influence on the cutting depth can be reduced by reducing the pulley accommodating portion 34 located below the center of the circular saw P. Since it can be made small, it becomes possible to ensure a sufficient depth of cut. In addition, since the intermediate shaft 62 is located on the opposite side of the cutting direction from the rotating shaft 51, that is, on the rear side, the enlargement of the main body to the cutting direction side is suppressed, and the visibility to the workpiece in front is improved. It is possible to ensure that workability is not impaired.

Next, an assembly process of the power transmission unit 6 to the pulley accommodating portion 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 thereto is inserted from the left into the through hole 341a of the pulley case 341. The rotating shaft 51 is supported by the pulley case 341 via the bearing 34A. In this state, the first pulley 61 is located in the transmission mechanism accommodation space 34a.

Next, the intermediate shaft 62 to 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 portion of the intermediate shaft 62 to which the bearing 34B is attached is fitted to the protrusion 341G, and the left end portion 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 accommodation 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 second left wall of the pulley case 341 is attached to the first plate 71 with the needle bearing 71B fixed to the inner periphery of the cylindrical portion 71A using a plurality of male screws. It fixes 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 is fitted to the inner ring of the needle bearing 71B. By supporting the left end portion of the rotation 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 rotation shaft 51 from being inclined with respect to 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 a 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 34 D and the bearing 34 E attached thereto is attached to the pulley case 341 from the right side. Specifically, the left end of the spindle 66 to which the needle bearing 34 D is attached is fitted into the recess 341 b 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 periphery of the protrusion 342A is attached along the contour of the third peripheral wall 341F of the pulley case 341. The third left wall 341C is fixed using a plurality of male screws. Specifically, the pulley so that the right end of the intermediate shaft 62 is fitted to the inner ring of the needle bearing 34C and the outer ring of the bearing 34E fixed to the spindle 66 is fitted to the first cylindrical part 342B. The cover 342 is attached to the pulley case 341 from the right side. When the left end portion of the intermediate shaft 62 is supported by the protruding portion 342A and the pulley cover 342 is fixed to the pulley case 341, it is possible to suitably suppress the intermediate shaft 62 from being inclined with respect to the left-right direction. Become.

As described above, according to the present embodiment, since the belt contact restricting portion 7 is provided, the contact between the first belt 64 and the second belt 68 can be restricted. The first belt 64 and the second belt 68 can be attached 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 the axis C direction of the spindle 66 in this order. As a result, both the first belt 64 and the second belt 68 can be arranged in the transmission mechanism accommodation space 34a from one side of the first left wall 341A of the pulley case 341, and assemblability 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 A V pulley may be used, and the first belt may be a V belt. In this case, the transmission performance due to friction may be improved 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, an electric circular saw 100, which is an example of a cutting machine according to a second embodiment of the present invention, will be described with reference to FIGS. The electric circular saw 100 basically has the same configuration as that of the electric circular saw 1 according to the first embodiment, and the same configuration as the electric circular saw 1 is denoted by the same reference numeral and described. Omitted where appropriate, different configurations will be mainly described. Moreover, about the structure same as the electric circular saw 1, there exists an effect similar to the effect demonstrated in description of 1st Embodiment.

The electric circular saw 100 includes a pulley accommodating portion 134 instead of the pulley accommodating portion 34, and includes a power transmitting portion 16 instead of the power transmitting portion 6.

The pulley housing part 134 includes a pulley case 1341 and a pulley cover 1342. As shown in FIG. 19, in the present embodiment, a transmission mechanism accommodation space 134 a that is recessed to the left of the pulley case 1341 is provided. The outline of the wall forming the transmission mechanism accommodation space 134a has a substantially rectangular shape.

19 and 20, the power transmission unit 16 includes a first pulley 161, a first intermediate shaft 162, a second pulley 163, a first belt 164, a third pulley 165, The second intermediate shaft 166, the fourth pulley 167, the second belt 168, the fifth pulley 169, the spindle 170, the sixth pulley 171, and the third belt 172 are included.

The first pulley 161 is a timing pulley and is configured in the same manner 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 disposed 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. 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 to the left side of the center portion of the first intermediate shaft 162 by press fitting, and rotates around 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 a smaller outer diameter than the second pulley 163. The third pulley 165 is fixed to the right side of the center portion of the first intermediate shaft 162 by press fitting, 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 disposed so as to extend in the left-right direction in parallel with the rotation 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 around 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. 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 to the left side of the center portion of the second intermediate shaft 166 by press fitting, and rotates around 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 a smaller outer diameter than the fourth pulley 167. The fifth pulley 169 is fixed to the right side of the center portion of the second intermediate shaft 166 by press fitting, 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 has the same configuration 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 of the spindle 170 and the front-rear direction (cutting direction). 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 suppress an increase in the size of the electric circular saw 100 in the direction perpendicular to the axis C direction of the spindle 170 and the cutting direction.

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. According to such a configuration, it is possible to suppress an increase in the size of the electric circular saw 100 in the cutting direction.

Further, at least a part of each of the rotation 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 the circular saw blade P when viewed in the direction of the axis C. As a result, it is possible to suppress an increase in size of the electric circular saw 100 in the vertical direction and the front-rear direction.

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 further 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. However, 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 chain saw. It is. From the viewpoint of ease of assembly, it is preferable that the belt can be stretched from one direction with other power tools.

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

Claims

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;
A second pulley formed larger in diameter than 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;
A cutting blade that receives the rotation of the second pulley and rotates.
It is possible to cut the workpiece by moving the cutting blade in the cutting direction,
At least a part of the first pulley is located at the same position as at least a part of the second pulley in a direction orthogonal to the axial direction of the output shaft and the cutting direction.
An intermediate shaft supported by the housing and supporting the second pulley;
A third pulley provided on the intermediate shaft, rotating around the axis and having a smaller diameter than the second pulley and rotating integrally with the second pulley;
An output shaft that is rotatably supported by the housing and on which the cutting blade can be mounted;
A fourth pulley provided on the output shaft, having a larger diameter than the third pulley and a smaller diameter than the second pulley, and rotating 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;
The cutting machine according to claim 1, wherein 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.
3. The cutting machine according to claim 1, wherein each of the rotation center of the first pulley and the rotation center of the second pulley is located at a position overlapping with the cutting blade when viewed in the axial direction. .
A base that supports the housing and moves in the cutting direction on the workpiece to cut the workpiece;
4. The cutting machine according to claim 1, wherein the rotation center of the second pulley is located at a position farther from the base than the rotation shaft. 5.
When viewed in the axial direction, a first line segment connecting the axis line of the rotation axis and the axis line of the intermediate shaft, a second line segment connecting the axis line of the intermediate shaft and the axis line of the output shaft, and the rotation axis The interior angle formed by the first line segment and the second line segment in a triangle formed by a third line segment connecting the axis line and the axis line of the output shaft is 90 degrees or less. Cutting machine as described in.
The cutting machine according to claim 5, wherein an interior angle formed by the second line segment and the third line segment in the triangle is 90 degrees or less.
Each of the internal angles in the said triangle is 90 degrees or less, The cutting machine of Claim 5 or 6 characterized by the above-mentioned.
A gear case having a wall that is recessed in the axial direction of the output shaft and forms a recess that houses the first belt and the second belt;
A regulation wall that regulates contact between the first belt and the second belt;
The motor further includes a motor body.
The cutting machine according to any one of claims 1 to 7, wherein a second belt, a regulating wall, a first belt, a wall portion, and a motor main body portion are arranged in the axial direction in this order.
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.
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;
A driven shaft supported by the housing;
A second pulley that is provided on the driven shaft and that rotates about the axis of the driven shaft and has a larger diameter than 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;
A cutting blade that is rotated by the rotational force of the second pulley being transmitted;
And a base having a hole for projecting a part of the cutting blade downward, the rotation center of the cutting blade being located below the rotation center of the first pulley. The cutting machine is characterized in that the rotation center of the two pulleys is located above the rotation center of the first pulley.
A third pulley that rotates integrally with the second pulley; a fourth pulley that transmits a rotational force of the third pulley; and a second belt that is stretched between the third pulley and the fourth pulley. The cutting machine according to claim 10, wherein the rotation center of the fourth pulley is at a position below the rotation center of the second pulley.
The cutting machine according to claim 10 or 11, 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 first pulley is located above the lower end of the second pulley and below the upper end when the direction perpendicular to the axial direction of the output shaft and the cutting direction is the vertical direction. The cutting machine according to 1 or 10.
The cutting machine according to claim 1 or 13, wherein when the cutting direction is a front-rear direction, the fourth pulley is located behind the front end of the second pulley and ahead of the rear end.
The cutting machine according to claim 13 or 14, wherein the first belt is a timing belt.