CN214561574U - Cutting machine - Google Patents

Abstract

The utility model provides a cut-off machine can restrain the cutter main part maximization and improve the equipment nature. The belt conveyor is provided with a first pulley (61) rotating integrally with a rotating shaft (51), a second pulley (63) rotating around an axis (B) of an intermediate shaft (62) and having a diameter larger than that of the first pulley (61), a first belt (64) transmitting the rotation of the first pulley (61) to the second pulley (63), a third pulley (65) rotating around the axis (B) of the intermediate shaft (62) and having a diameter smaller than that of the second pulley (63) and rotating integrally with the second pulley (63), a fourth pulley (67) rotating integrally with a main shaft (66) and having a diameter larger than that of the third pulley (65) and having a diameter smaller than that of the second pulley (63), and a second belt (68) transmitting the rotation of the third pulley (65) to the fourth pulley (67), wherein at least a part of the first pulley (61) and the second pulley (63) are orthogonal to the direction of the axis (C) of the main shaft (66) and the cutting direction) Are located at the same position.

Description

Cutting machine

Technical Field

The utility model relates to a cut-off machine.

Background

Conventionally, electric circular saws have been widely used as cutting machines for cutting wood, pipes, and the like (materials to be cut). For example, patent document 1 discloses an electric circular saw in which a plurality of gears are provided in a rotational force transmission mechanism for transmitting a rotational force of a motor to an output shaft, and the rotational force of the motor is transmitted by meshing the gears.

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, and therefore, noise may be generated by meshing of the gears.

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

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-011283

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

However, since the distance between the pulleys needs to be obtained in the case of the belt drive system as compared with the conventional gear engagement system, there is a possibility that the cutter body becomes large in the case of the belt drive system employed in the above-mentioned electric circular saw. Further, since the cutting depth may be reduced when the pulley having a large diameter is attached to the output shaft, when the rotation of the motor is decelerated and transmitted to the output shaft, a structure in which a plurality of belts are provided and the deceleration is performed in multiple stages is necessary, and there is a possibility that the cutter body is further enlarged and the assembly is difficult.

Therefore, an object of the present invention is to suppress an increase in size of a cutter body having high quietness. In addition, as another problem, an object of the present invention is to provide a cutting machine capable of improving assembling performance.

Means for solving the problems

In order to solve the above problems, the present invention provides a cutting machine including 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, a second pulley formed to have a diameter larger than that of the first pulley, a first belt stretched between the first pulley and the second pulley and transmitting rotation of the first pulley to the second pulley, a cutting blade transmitting rotation of the second pulley, an output shaft rotatably supported by the housing and to which the cutting blade is attached, the cutting machine being capable of cutting a workpiece by moving the cutting blade in a 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.

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

The cutting device further includes an intermediate shaft supported by the housing and supporting the second pulley, a third pulley provided on the intermediate shaft and rotating around an axis of the intermediate shaft, the third pulley being formed to have a diameter smaller than that of the second pulley and to rotate integrally with the second pulley, a fourth pulley provided on the output shaft, the fourth pulley being formed to have a diameter larger than that of the third pulley and smaller than that of the second pulley and to rotate integrally with the output shaft, and a second belt stretched between the third pulley and the fourth pulley and transmitting rotation of the third pulley to the fourth pulley, wherein at least a part of the second pulley is preferably located at the same position as at least a part of the fourth pulley in the cutting direction.

With this configuration, the size of the cutter in the cutting direction can be suppressed from increasing.

In the axial direction, it is preferable that a rotation center of the first pulley and a rotation center of the second pulley are located at positions overlapping the cutting blade, respectively.

According to this configuration, since the rotary shaft and at least a part of the intermediate shaft are disposed so as to overlap the side surface of the cutting blade in the axial direction view of the output shaft, it is possible to suppress an increase in size of the cutting machine.

In the axial view, an inner angle formed by the first line segment and the second line segment in a triangle formed by 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 a third line segment connecting the axis of the rotary shaft and the axis of the output shaft is preferably 90 degrees or less.

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

In the triangle, an inner angle formed by the second line segment and the third line segment is preferably 90 degrees or less.

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

The internal angles in the triangle are preferably 90 degrees or less, respectively.

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

The workpiece cutting device may further include a base that supports the housing and moves on the workpiece in the cutting direction to cut the workpiece, and the intermediate shaft may be supported by the housing at a position that is spaced apart from the base with respect to the rotation axis.

According to this configuration, since the intermediate shaft to which the pulley having a relatively large diameter is attached is separated from the base, the cutting depth can be sufficiently secured.

The motor further includes a pulley housing having a wall portion forming a recess recessed in the axial direction of the output shaft and accommodating the first belt and the second belt, and a restricting wall restricting contact between the first belt and the second belt, and the motor further includes a motor main body portion, and the second belt, the restricting wall, the first belt, the wall portion, and the motor main body portion are preferably arranged in this order in the axial direction.

According to this configuration, since the restricting wall restricts contact between the first belt and the second belt, both the first belt and the second belt can be disposed in the recess from one side of the wall portion of the pulley housing. This can improve the assembling property.

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 preferably timing pulleys.

According to such a configuration, even when a high load is applied to the cutting blade, the occurrence of a gap or the like can be suppressed, and thus an efficient and stable cutting operation can be performed. Further, by using the timing belt and the timing pulley, the rotational transmission efficiency can be improved as compared with a friction transmission type belt, and the belt can be prevented from slipping and from being damaged, so that the durability of the tool can be improved.

The utility model also provides a cutting machine, which comprises a housing, a motor supported by the housing and having a rotating shaft, a first belt pulley arranged on the rotating shaft and rotating integrally with the rotating shaft, a driven shaft supported by the housing, a second belt pulley arranged on the driven shaft and rotating around the axis of the driven shaft and having a diameter larger than that of the first belt pulley, a first belt stretched and erected on the first belt pulley and the second belt pulley and transmitting the rotation of the first belt pulley to the second belt pulley, a cutting saw blade transmitting the rotation force of the second belt pulley and rotating, a base supporting the housing and having a hole part protruding downwards, 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.

According to the above configuration, by positioning the second pulley away from the rotation center of the cutting blade, the large second pulley can be easily disposed, and the size of the cutting machine can be suppressed from increasing.

Preferably, the belt conveyor includes 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 stretched over the third pulley and the fourth pulley, and a rotational center of the fourth pulley is located below a rotational center of the second pulley.

With this configuration, the size of the cutter in the cutting direction can be suppressed from increasing.

When a direction orthogonal to the axial direction of the output shaft and the cutting direction is a vertical direction, the first pulley is preferably located above a lower end and below an upper end of the second pulley.

When the cutting direction is the front-rear direction, the fourth pulley is preferably positioned rearward of the front end and forward of the rear end of the second pulley.

The utility model also provides a cutter possesses: 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; an intermediate shaft supported by the housing and supporting the second pulley; a first belt stretched between the first pulley and the second pulley and transmitting rotation of the first pulley to the second pulley; a third pulley provided on the intermediate shaft and rotating integrally with the second pulley; an output shaft rotatably supported by the housing and to which a cutting blade can be attached; a fourth pulley provided on the output shaft and rotating integrally with the output shaft; and a second belt stretched between the third pulley and the fourth pulley and transmitting rotation of the third pulley to the fourth pulley, wherein the material to be processed can be cut by moving the cutting blade in a cutting direction, and 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.

The second pulley is formed to have a larger diameter than the first pulley, the third pulley is formed to have a smaller diameter than the second pulley, and the fourth pulley is formed to have a larger diameter than the third pulley and a smaller diameter than the second pulley.

Effect of the utility model

According to the utility model discloses a cut-off machine can restrain the cutter main part macro-scale. In addition, the assembling property can be improved while ensuring the quietness.

Drawings

Fig. 1 is a right side view showing an appearance of an electric circular saw according to a first embodiment of the present invention.

Fig. 2(a) is a plan view of the electric circular saw according to the first embodiment of the present invention, and shows a partial cross section. Fig. 2(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.

Fig. 3 is a left side view showing an external appearance of the electric circular saw according to the first embodiment of the present invention, and shows a partial cross section of the handle portion.

Fig. 4 is an enlarged view of the cutting depth adjusting mechanism of the electric circular saw according to the first embodiment of the present invention.

Fig. 5 is a perspective view showing a state in which the first stage transmission mechanism of the electric circular saw according to the first embodiment of the present invention is accommodated in the pulley accommodation portion.

Fig. 6 is a perspective view showing a state in which the power transmission unit and the belt contact restricting unit of the electric circular saw according to the first embodiment of the present invention are accommodated in the pulley accommodating unit.

Fig. 7 is a perspective view showing an appearance of a pulley housing portion of the electric circular saw according to the first embodiment of the present invention.

Fig. 8 is a schematic diagram showing a positional relationship of the motor shaft, the intermediate shaft, and the main shaft in a right side view.

Fig. 9 is a sectional view taken along line IX-IX of fig. 8.

Fig. 10 is a cross-sectional view taken along line X-X of fig. 8.

Fig. 11 is a sectional view through the axis of the intermediate shaft of the electric circular saw according to the first embodiment of the present invention, parallel to the axis of the intermediate shaft.

Fig. 12 is a right side view showing a positional relationship among the motor shaft, the intermediate shaft, and the spindle of the electric circular saw according to the first embodiment of the present invention.

Fig. 13 is a diagram (1) illustrating a process of assembling the power transmission unit of the electric circular saw according to the first embodiment of the present invention to the pulley case.

Fig. 14 is a diagram (2) illustrating a process of assembling the power transmission unit of the electric circular saw according to the first embodiment of the present invention to the pulley case.

Fig. 15 is a diagram (fig. 3) illustrating a process of assembling the power transmission unit of the electric circular saw according to the first embodiment of the present invention to the pulley case.

Fig. 16 is a diagram (4) illustrating a process of assembling the power transmission unit of the electric circular saw according to the first embodiment of the present invention to the pulley case.

Fig. 17 is a view (5) illustrating a process of assembling the power transmission unit of the electric circular saw according to the first embodiment of the present invention to the pulley case.

Fig. 18 is a view (fig. 6) illustrating a process of assembling the power transmission unit of the electric circular saw according to the first embodiment of the present invention to the pulley case.

Fig. 19 is a right side view showing a positional relationship among the motor shaft, the first intermediate shaft, the second intermediate shaft, and the main shaft of the electric circular saw according to the second embodiment of the present invention.

Fig. 20 is a cross-sectional view of the power transmission unit of the electric circular saw according to the second embodiment of the present invention passing through respective axes of the motor shaft, the first intermediate shaft, the second intermediate shaft, and the main shaft.

Fig. 21 is a diagram for explaining an effect of the electric circular saw according to the second embodiment of the present invention.

Detailed Description

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

In the following description, "front" shown in the drawings is defined as a front direction, "rear" is defined as a rear direction, "up" is defined as an up direction, and "down" is defined as a down direction. In addition, "right" when the electric circular saw 1 is viewed from the rear is defined as a right direction, and "left" is defined as a left direction. In the present specification, when a dimension, a numerical value, or the like is referred to, not only a dimension and a numerical value that completely match the dimension, the numerical value, or the like, but also a substantially matching dimension, the numerical value, or the like (for example, a dimension within a manufacturing error range) is included. The terms "same", "orthogonal", "parallel", "aligned with" and the like also include the meanings of "substantially the same", "substantially orthogonal", "substantially parallel", "substantially aligned", and the like.

As shown in fig. 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 restricting unit 7.

As shown in fig. 1 to 3, the base 2 supports the housing 3. The base 2 is made of metal such as aluminum, for example, and has a substantially rectangular shape in bottom view while extending in the front-rear direction. A long hole 2A extending in the front-rear direction and allowing entry of the circular saw blade P is formed in the center portion in the left-right direction of the base 2. The circular saw blade P extends downward through the elongated hole 2A from above. The length of the circular saw blade P projecting downward from the bottom surface of the base 2 is the depth of cut. The long hole 2A is an example of a "hole portion" in the present invention. The longitudinal direction of the base 2 coincides with the cutting direction in the case of cutting by the electric circular saw 1, 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 the cutting operation. In order to cut the material to be cut during the operation, the operator can move 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. As shown in fig. 1 and 2, the base 2 includes 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 "material to be processed" in the present invention. The front-back 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 in the front portion of the base 2. As shown in fig. 2, the housing rotation support portion 21 has a substantially コ shape in plan view. The shaft 22 is provided above the housing rotation support portion 21 and extends in the left-right direction.

As shown in fig. 1 to 3, the housing 3 is an outer shell of the electric circular saw 1, and includes a motor housing portion 31, a substrate housing portion 32, a handle portion 33, a pulley housing portion 34, a saw cover 35, and a protection cover 36. As shown in fig. 2, a power supply line 3A having a plug portion connectable to a commercial ac power supply extends leftward from a left rear portion of the housing 3. Power supply line 3A is electrically connected to motor 5 inside housing 3, and a plug portion of power supply line 3A is connected to a commercial ac power supply, whereby power supply to motor 5 is enabled. The housing 3 is an example of the "housing" in the present invention.

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

As shown in fig. 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 a cutting operation. A manually operable trigger switch 3B for controlling the start and stop of the motor 5 is provided on the handle portion 33.

As shown in fig. 2(a), the pulley housing portion 34 is provided on the right side of the motor housing portion 31, and the pulley housing portion 34 is made of, for example, metal and houses the power transmission portion 6. Further, the pulley housing 34 is provided with a rotation restriction member 3C. Not shown in the drawings, an engaging portion having a substantially コ 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 is configured such that a part thereof extends forward from the pulley housing portion in a state where no external force is applied. The detailed structure of the pulley housing 34 will be described later.

The saw cover 35 shown in fig. 1 is made of, for example, metal, and is attached to the pulley housing 34. The saw cover 35 covers an upper side portion of the circular saw blade P. The saw cover 35 may be formed integrally with the pulley housing 34 and made of the same material. A shaft 22 provided at the upper portion of the housing turning support portion 21 of the base 2 is inserted through the front end portion of the saw cover 35. The saw cover 35 can rotate with respect to the base 2 with the shaft 22 as a center. The shaft 22 is rotated about the center of the base 2 by the saw cover 35, and 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 integrated with each other, and the shaft 22 is rotated about the center of the base 2.

The protective cover 36 is made of, for example, resin, and is provided to the saw cover 35. The protective cap 36 is formed so as to be rotatable along the outer edge of the saw cover 35. A not-shown urging member is provided between the saw cover 35 and the protective cover 36. The urging member urges the protection cover 36 in a direction to cover the lower side of the circular saw blade P. Thus, the guard 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 projection of the circular saw blade P downward from the bottom surface (elongated hole 2A) of the base 2, and includes a link portion 41, a regulating portion 42, and a shaft 43, as shown in fig. 2 to 4. 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. 2(b), the lower end of the link portion 41 is fixed to the upper surface of the base 2 by a screw. The link portion 41 is located outside the housing 3, and has an arc shape protruding upward from the upper surface of the base 2 and curved 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 closest to the base 2 and the other end portion 41B located 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 through the circular 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 movement of the shaft 43 along the arc groove 41 a. 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 supported rotatably with respect to the base 2, and is configured to be changeable in relative position with respect to the base 2. With this 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 is movable downward along the arc groove 41A to be able to contact the one end portion 41A of the link portion 41, and the shaft 43 is movable upward along the arc groove 41A to be able to contact 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 stem portion 42B is integrally formed with the base portion 42A. I.e. rotatably supported to the saw cover 35. The lever 42B is operated by a worker to rotate about an axis extending in the left-right direction.

The cam 42C is tubular and formed in a substantially elliptical shape in side view. The base 42A is fitted to the inner peripheral surface of the cam 42C. Thereby, the cam 42C is rotatable 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 pressing member 42E has an inner diameter larger than an outer diameter of the shaft 42D, and the pressing member 42E is configured to be movable in the vertical and longitudinal directions with respect to the shaft 42D. In other words, the pressing member 42E is engaged (fitted) with the shaft 42D with a gap, and is configured to be movable relative to the shaft 42D. By the rotation of 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 member 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. Therefore, when the lever portion 42B rotates in the clockwise direction in fig. 4 (the direction of arrow X in fig. 4), the cam 42C rotates in the clockwise direction in fig. 6 so that the longitudinal direction of the cam 42C is substantially orthogonal to the pressing surface 41C of the link portion 41, and the pressing member 42E moves in the direction approaching the pressing surface 41C in accordance with the rotation of the cam 42C, so that the outer peripheral surface of the pressing member 42E can press the pressing surface 41C. The outer peripheral surface of the pressing member 42E presses the pressing surface 41C, thereby fixing the relative position of the housing 3 with respect to the base 2. Further, by rotating the cam 42C to a position where the axial direction thereof 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 pressing of the outer peripheral surface of the pressing member 42E against the pressing surface 41C can be released.

The motor 5 shown in fig. 2 is a drive source for driving the power transmission unit 6, and in the present embodiment, is a DC brushless motor. The motor 5 mainly includes a motor main body 50, a rotary 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 leftward from the pulley housing 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 rotary 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 rotation shaft 51 is provided with an engaged portion 51A parallel to the left-right direction and formed with two surfaces parallel to each other. In the present embodiment, the rotation of the rotating shaft 51 can be regulated by the worker pressing the rotation regulating member 3C inward of the pulley housing portion 34 against the biasing force of the biasing member, not shown, and engaging the engaging portion, not shown, of the rotation regulating member 3C with the engaged portion 51A. By restricting the rotation of the rotary shaft 51, the rotation of the circular saw blade P can be restricted by the power transmission unit 6, and the circular saw blade P can be appropriately replaced. The rotary shaft 51 is an example of the "rotary shaft" in the present invention. The axis a is an example of "the axis of the rotating shaft" and "the rotation center of the first pulley" in the present invention.

Fan 52 is a centrifugal fan and is fixed to rotary shaft 51 so as to be rotatable integrally with rotary shaft 51.

Next, the detailed structure of the pulley housing portion 34, the power transmission portion 6, and the belt contact restricting portion 7 will be described.

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

As shown in fig. 5 to 7, the pulley housing 341 mainly has a first left wall 341A, a second left wall 341B, a third left wall 341C, a first peripheral wall 341D, a second peripheral wall 341E, and a 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 front-rear direction. 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 a "wall portion" in the present invention.

The through hole 341A penetrates the first left wall 341A in the left-right direction. Bearing 34A is fitted into through hole 341 a. The rotary shaft 51 of the motor 5 is rotatably supported to the pulley housing 341 through a bearing 34A.

The projection 341G protrudes rightward from the right surface of the first left wall 341A, and has a substantially circular shape in right view. Bearing 34B is fitted to the inner peripheral surface of projection 341G.

As shown in fig. 5, the second left wall 341B extends in the vertical front-rear direction and is positioned rightward of the first left wall 341A. A female screw hole 341B1 extending leftward from the right face of the second left wall 341B is formed in the second left wall 341B. As shown in fig. 5 and 10, a concave portion 341B is formed in the second left wall 341B.

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

As shown in fig. 5, the third left wall 341C extends in the vertical front-rear direction and is positioned rightward of the first left wall 341A and the second left wall 341B. A female screw hole 341C1 extending leftward from the right face of the third left wall is formed in the third left wall 341C.

The fourth left wall 341S extends in the vertical front-rear direction, and is located rightward 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 341D is formed to be flush with the inner peripheral surface of the second peripheral wall 341E in the upper portion 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 contour of the third peripheral wall 341F in a right side view, and is fixed to the pulley housing 341 by being press-fitted and tightened from the right side of the pulley housing. The pulley cover 342 has a protruding portion 342A, a first cylindrical portion 342B, and a second cylindrical portion 342C.

As shown in fig. 7, 9, and 10, the projecting portion 342A has a bottomed cylindrical shape projecting rightward from the right surface of the pulley cover 342. The needle bearing 34C is fitted to the projection 342A.

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

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

Further, as shown in fig. 5, a transmission housing space 34a is provided which is recessed stepwise leftward from the third left wall 341C of the pulley housing 341. More specifically, the transmission mechanism housing 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 housing space 34a is an example of the "concave portion" in the present invention.

As shown in fig. 5 and 6, the power transmission unit 6 is a portion for transmitting 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, a second pulley 63, a first belt 64, a third pulley 65, a main shaft 66, a fourth pulley 67, and a second belt 68. Among them, the first pulley 61, the second pulley 63, and the first belt 64 constitute a first stage transmission mechanism, and the third pulley 65, the fourth pulley 67, and the second belt 68 constitute a second stage transmission mechanism. Further, the first stage transmission mechanism and the second stage transmission mechanism are housed in the transmission mechanism housing space 34 a.

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 press-fitted and fixed to the rotary shaft 51 of the motor 5 on the right side of the first left wall 341A of the pulley housing 341, and rotates integrally with the rotary 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 parallel to the rotation shaft 51 so as to extend in the left-right direction. As shown in fig. 9, the intermediate shaft 62 is rotatably supported by the pulley housing 341 through a bearing 34B and by the pulley cover 342 through a 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 an "intermediate shaft" in the present invention.

The second pulley 63 shown in fig. 5 is a timing pulley, and 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 larger than that 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. A plurality of female screw holes 63a extending leftward from the right surface of the second pulley 63 are formed in the second pulley 63. 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 rotation center of the second pulley" in the present invention.

The first belt 64 is an endless resin belt, and is a timing belt having gear-shaped irregularities formed on an inner circumferential surface thereof. The first belt 64 is stretched between the first pulley 61 and the second pulley 63 by having its front portion wound around the outer periphery of the first pulley 61 and its rear portion wound around the outer periphery 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 smaller than that 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 integrally with the intermediate shaft 62 about the axis B. The third pulley 65 is an example of the "third pulley" in the present invention.

As shown in fig. 6, the main shaft 66 is disposed parallel to the rotary shaft 51 and the intermediate shaft 62 and extends in the left-right direction, and is rotatably supported by the pulley housing 341 through the needle bearing 34D and the pulley cover 342 through the bearing 34E (see fig. 10). The main shaft 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 on the right end portion of the main shaft 66. The mounting portion 66A protrudes to the right (outer side) of the pulley cover 342. The main shaft 66 is an example of an "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 thereof. The fourth pulley 67 has an outer diameter larger than that of the third pulley 65. In addition, 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 main shaft 66 by press fitting, and rotates around the axis line C integrally with the main shaft 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" and "the rotation center of the fourth pulley" and "the rotation center of the cutting blade" in the present invention.

The second belt 68 is an endless belt made of resin and formed in an endless shape, and is a timing belt having gear-shaped irregularities formed on an inner circumferential surface thereof. The second belt 68 is stretched between the third pulley 65 and the fourth pulley 67 by having its upper portion wound around the outer periphery of the third pulley 65 and its lower portion wound around the outer periphery of the fourth pulley. The second belt 68 is an example of the "second belt" in the present invention.

The circular saw blade P is substantially circular plate-shaped, is detachably fixed to the mounting portion 66A of the main shaft 66, and is rotatably supported together with the main shaft 66. The circular saw blade P is an example of the "cutting blade" of the present invention.

As described above, the primary transmission mechanism (the first pulley, the second pulley, and the first belt 64) and the secondary transmission mechanism (the third pulley 65, the fourth pulley 67, and the second belt 68) are composed of a synchronous pulley and a synchronous belt. Thus, even when a high load is applied to the circular saw blade P, the occurrence of a gap or the like can be suppressed, and therefore, the cutting operation can be performed efficiently and stably. Further, by using the timing belt and the timing pulley, the transmission efficiency of the rotation is improved and the damage of the belt is suppressed, so that the durability of the tool can be improved.

The belt contact regulating portion 7 shown in fig. 6 is for regulating the contact between the first belt 64 and the second belt 68, and includes a first plate 71 and a second plate 72. The belt contact restricting portion 7 is an example of the "restricting 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. The first plate 71 is fixed to the second left wall 341B of the pulley housing 341 using a plurality of male bolts. As shown in fig. 6 and 9, the first plate 71 has a cylindrical portion 71A.

The cylindrical portion 71A has a bottomed cylindrical shape extending rightward from the right surface of the first plate 71. A needle bearing 71B is fixed to an inner circumferential surface of the cylindrical portion 71A. The cylindrical portion 71A supports the right end of the rotary shaft 51 of the motor 5 via a needle bearing 71B. By supporting the rotary shaft 51 on the cylindrical portion 71A, the first plate 71 is fixed to the pulley housing 341, and the inclination of the rotary shaft 51 with respect to the left-right direction can be appropriately suppressed.

The second plate 72 shown in fig. 6 has a substantially circular plate 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 using a plurality of male bolts. As shown in fig. 9 and 10, the second plate 72 includes a restricting 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 an 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 restriction portion 72A is formed slightly larger than the outer diameter of the second pulley 63.

The protrusion 72B has a substantially circular ring shape in a right side view, and protrudes slightly to the right than the other portion of the second plate 72. In the present embodiment, as shown in fig. 11, the projecting portion 72B projects rightward with a width D1 from the other portion of the second plate 72. Thus, when the second belt 68 is moved (rotated) relative to the second plate 72, the contact area between the lateral surface (left surface) of the second belt 68 in the width direction and the right surface of the second plate 72 when the second belt 68 is in contact with the second plate 72 can be reduced (see D2 in the figure). With such a configuration, damage 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 can be suppressed.

In the present embodiment, the first belt 64 and the second belt 68 are arranged to overlap in the front view by providing the belt contact restricting portion 7.

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 up-down 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 axial direction C of the main shaft 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. With this configuration, the electric circular saw 1 can be prevented from being increased in size in the direction (vertical direction) orthogonal to the axis C direction and the cutting direction of the spindle 66.

In addition, 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 rearward of the front end of the second pulley 63 and forward of the rear end of the second pulley 63. With this configuration, the electric circular saw 1 can be prevented from being increased in size in the cutting direction.

In addition, at least a part of each of the rotary shaft 51 of the motor 5 and the intermediate shaft 62 is positioned to overlap the circular saw blade P (see fig. 1) in the view of the axis C direction. This can suppress an increase in the size of the electric circular saw 1 in the vertical and front-rear directions.

In the present embodiment, in the axial C direction, each of the inner angles in a triangle formed by the first line segment (i) connecting the axis a of the rotary shaft 51 and the axis B of the intermediate shaft 62, the second line segment (ii) connecting the axis B and the axis C, and the third line segment (iii) connecting the axis a and the axis C is 90 degrees or less. Specifically, an angle α formed by the first line segment (i) and the second line segment (ii), an angle β formed by the second line segment (ii) and the third line segment (iii), and an angle γ formed by the third line segment (iii) and the first line segment (i) are respectively 90 degrees or less. With this configuration, 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 can be suppressed from increasing. With the above-described configuration, the electric circular saw 1 can be downsized, and since the pulleys are close to each other, the circumferential region (contact angle) of the pulley that can come into contact with the belt is reduced. This effect is particularly remarkable in the case where the fourth pulley 67 is disposed in a front-rear and vertical direction with respect to the first pulley 61. In the present embodiment, the rotation transmission is performed favorably by using both the first belt 64 and the second belt 68 as timing belts, but at least one of the belts may be a timing belt. For example, the first belt 64 may be a belt that performs transmission by friction transmission (e.g., a V-belt in which V-shaped grooves are formed in the rotational direction), the first pulley 61 and the second pulley 63 may be shaped to correspond to the V-belt, and the second belt 68 may be a timing belt. The second belt 68 transmits the rotational force of the decelerated high torque, and is therefore suitable for a rotation transmission mode by gear engagement like a synchronous belt.

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 degrees or less, but may be configured such that at least one angle is 90 degrees or less.

Next, an operation of transmitting the rotation of the motor 5 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 started, and the rotation shaft 51 rotates integrally with the first pulley 61. With this rotation, the first belt 64 rotates as the irregularities on the outer peripheral surface of the first pulley mesh with the irregularities on the inner peripheral surface of the first belt 64 wound around the first pulley 61. With this rotation, the second pulley 63 and the intermediate shaft 62 rotate integrally, as the irregularities on the outer peripheral surface of the second pulley 63 mesh with the irregularities on the inner peripheral surface of the first belt 64 wound around the second pulley 63. Here, since the second pulley 63 is formed larger in diameter than the first pulley 61, the rotation of the rotary 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 the rotation to the intermediate shaft 62 (the second pulley 63).

When the intermediate shaft 62 rotates, the third pulley 65 fixed to the intermediate shaft 62 rotates at the same rotational speed together with the intermediate shaft 62 and the second pulley 63. With this rotation, the second belt 68 rotates as the irregularities on the outer peripheral surface of the third pulley mesh with the irregularities on the inner peripheral surface of the second belt 68 wound around the third pulley. With this rotation, the irregularities on the outer peripheral surface of the fourth pulley 67 mesh with the irregularities on the inner peripheral surface of the second belt 68 wound around the fourth pulley 67, and the fourth pulley 67 rotates integrally with the main shaft 66. Here, since the fourth pulley is formed to have a larger diameter than the third pulley 65, the rotation of the intermediate shaft 62 is decelerated and transmitted to the main shaft 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 the rotation to the main shaft 66.

In this state, as shown in fig. 9, even when the first belt 64 moves rightward with respect to the first pulley 61 and the second pulley 63, the left surface of the first plate 71 and the left surface of the regulating portion 72A of the second plate 72 abut against the right side surface in the width direction of the first belt 64, and the movement of the first belt 64 in the right direction is regulated. As shown in fig. 10, even when the second belt 68 moves leftward with respect to the third belt 65, the right surface of the projection 72B of the second plate 72 abuts against the left surface of the second belt 68 in the width direction, and movement of the second belt 68 leftward is restricted. This can suppress contact between the first belt 64 and the second belt 68, and can suppress damage to the power transmission unit 6.

When the main shaft 66 rotates, the circular saw blade P attached to the attachment portion 66A of the main shaft 66 rotates together with the main shaft 66 at the same rotational speed. That is, the rotation of the rotary 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 expansion ratio of the diameter of the fourth pulley 67 with respect to the diameter of the third pulley 65 is made smaller than the expansion ratio of the diameter of the second pulley 63 with respect to the diameter of the first pulley 61 so that the reduction ratio of the first stage transmission mechanism is larger than the reduction ratio of the second stage transmission mechanism.

In addition, the power transmission unit 6 according to the present embodiment performs speed reduction in two stages, and thus does not require a large-diameter pulley to be provided on the main shaft 66. In the present embodiment, the second pulley 63 having a larger diameter than the fourth pulley 67 provided on the main shaft 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, the cutting depth can be sufficiently secured. More specifically, since the intermediate shaft 62 is located at a position spaced apart from the base 2, i.e., above the rotary shaft 51 and away from the rotational center of the circular saw blade P, the second pulley 63 having a large diameter can be accommodated without increasing the size of the pulley accommodating portion 34, and a sufficient reduction ratio can be obtained by the first-stage reduction. As a result, the diameter of the fourth pulley 67 (final pulley) can be minimized as much as necessary, and the pulley housing 34 located below the center of the circular saw blade P can be reduced, whereby the influence on the cutting depth can be reduced, and the cutting depth can be sufficiently ensured. Further, since the intermediate shaft 62 is located on the opposite side to the cutting direction, that is, on the rear side of the rotary shaft 51, the size of the main body on the cutting direction side is suppressed from increasing, visual confirmation of the workpiece located on the front side is ensured, and reduction in workability can be suppressed.

Next, the assembly process of the power transmission part 6 into the pulley housing part 34 in the electric circular saw 1 according to the first embodiment will be described with reference to fig. 13 to 18.

First, as shown in fig. 13, the rotating shaft 51 of the motor 5 in a state where the first pulley 61, the bearing 34A, and the needle bearing 71B are attached is inserted into the through hole 341a of the pulley housing 341 from the left. The rotary shaft 51 is supported to the pulley housing 341 through the bearing 34. In this state, the first pulley 61 is located in the transmission housing space 34 a.

Next, the intermediate shaft 62 with the second pulley 63, the third pulley 65, the bearing 34B, and the needle bearing 34C attached thereto is attached to the pulley housing 341 from the right. Specifically, the left end portion of the intermediate shaft 62 to which the bearing 34B is attached is fitted into the projection 341G, and the left end portion of the intermediate shaft 62 is fixed to the pulley housing 341. In this state, the intermediate shaft 62, the second pulley 63, and the third pulley 65 are located in the transmission housing space 34 a.

Next, as shown in fig. 14, the first belt 64 is wound around the first pulley 61 and the second pulley 63 from the right.

Next, as shown in fig. 15, the first plate 71 with the needle bearing 71B fixed to the inner periphery of the cylindrical portion 71A is fixed to the second left wall 341B of the pulley housing 341 using a plurality of male bolts. Specifically, the first plate 71 is attached to the pulley housing 341 from the right side so that the end portion of the rotary shaft 51 is fitted into the inner ring of the needle bearing 71B. By supporting the left end portion of the rotating shaft 51 in the cylindrical portion 71A and fixing the first plate 71 to the pulley housing 341, it is possible to appropriately suppress the rotating shaft 51 from being inclined with respect to the left-right direction.

Next, the second plate 72 is fixed to the right surface of the second pulley 63 using a plurality of male bolts. Specifically, second plate 72 is attached to pulley housing 341 from the right side in such a manner that third pulley 65 is inserted through an insertion hole located at a substantially central portion in the radial direction of second plate 72.

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

Next, as shown in fig. 17, the second belt 68 is wound around the third pulley 65 and the fourth pulley 67 from the right.

Finally, as shown in fig. 10 and 18, the pulley cover 342 in a state where the needle bearing 34C is fixed to the inner periphery of the protrusion 342A is attached to the pulley housing 341 along the contour of the third peripheral wall 341F of the pulley housing 341, and is fixed to the third left wall 341C using a plurality of male bolts. Specifically, the pulley cover 342 is attached to the pulley housing 341 from the right so that the right end portion 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 main shaft 66 is fitted to the first cylindrical portion 342B. 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 housing 341, whereby the inclination of the intermediate shaft 62 with respect to the left-right direction can be appropriately suppressed.

As described above, according to the present embodiment, since the contact between the first belt 64 and the second belt 68 can be restricted by providing the belt contact restricting portion 7, the motor 5 can be attached from one side (left side) of the pulley housing 341, and the first belt 64 and the second belt 68 can be attached from the other side (right side) of the pulley housing 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 axial direction C of the spindle 66. Thus, both the first belt 64 and the second belt 68 can be disposed in the transmission housing space 34a from the side of the first left wall 341A of the pulley housing 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 synchronous pulleys, and the first belt 64 is a synchronous belt, but the first pulley and the second pulley may be V-shaped pulleys, and the first belt may be a V-belt. In this case, a belt contact angle (a contact surface with the belt) of the first pulley 61 is increased by a tensioner, an idler pulley, or the like, so that transmission performance using friction can be improved.

Next, an electric circular saw 100 as an example of a cutting machine according to a second embodiment of the present invention will be described with reference to fig. 19 and 21. The electric circular saw 100 has basically the same configuration as the electric circular saw 1 of the first embodiment, and the same configuration as the electric circular saw 1 is denoted by the same reference numerals and description thereof is omitted as appropriate, and different configurations will be mainly described. The same structure as that of the electric circular saw 1 produces the same effects as those described in the description of the first embodiment.

The electric circular saw 100 includes a pulley housing 134 instead of the pulley housing 34 and a power transmission unit 16 instead of the power transmission unit 6.

The pulley housing 134 includes a pulley case 1341 and a pulley cover 1342. As shown in fig. 19, in the present embodiment, a transmission housing space 134a is provided which is recessed to the left of the pulley case 1341. The outline of the wall forming the transmission housing space 134a is substantially quadrangular.

As shown in fig. 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, a second intermediate shaft 166, a fourth pulley 167, a second belt 168, a fifth pulley 169, a main shaft 170, a sixth pulley 171, and a third belt 172.

The first pulley 161 is a timing belt, and is configured similarly to the first pulley 61 of the electric circular saw 1 according to 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 parallel to the rotation shaft 51 in the left-right direction. The first intermediate shaft 162 is rotatably supported in the pulley receiving portion 134 by 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 that of the first pulley 161. In addition, the second pulley 163 has a smaller outer diameter than 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 line 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 shaft" in the present invention.

The first belt 164 is a timing belt, and is wound around 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 press-fitted and fixed to the right side of the central portion of the first intermediate shaft 162, and rotates around the axis line 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 parallel with the rotary shaft 51 and the first intermediate shaft 162 in the left-right direction. The second intermediate shaft 166 is rotatably supported in the pulley receiving portion 134 by 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 belt having an outer diameter larger than that of the third pulley 165. In addition, the fourth pulley 167 has a smaller outer diameter than the second pulley 63 of the electric circular saw 1 in the first embodiment. The fourth pulley 167 is press-fitted and fixed to the left side of the central portion of the second intermediate shaft 166, 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 shaft" in the present invention.

The second belt 168 is a timing belt, and is wound around the third pulley 165 and the fourth pulley 167. The second belt 168 is an example of the "second belt" of the present invention.

The fifth pulley 169 is a timing belt having a smaller outer diameter than the fourth pulley 167. The fifth pulley 169 is press-fitted and fixed to the right side of the central portion of the second intermediate shaft 166, and rotates around 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 main shaft 170 extends in the left-right direction, and is configured in the same manner as the main shaft 66 of the electric circular saw 1 according to the first embodiment. The main shaft 170 is an example of the "output shaft" in the present invention.

The sixth pulley 171 is a timing belt and is configured in the same manner as the fourth pulley 67 of the electric circular saw 1 according to the first embodiment. The sixth pulley 171 is an example of the "sixth pulley" in the present invention.

The third pulley 172 is a timing belt, and is wound around 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 main shaft 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. With this configuration, the electric circular saw 100 can be prevented from being increased in size in the direction orthogonal to the axis C of the spindle 170 and the cutting direction.

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 this configuration, the size of the electric circular saw 100 in the cutting direction can be suppressed from increasing.

In addition, at least a part of each of the rotary shaft 51, the first intermediate shaft 162, the second intermediate shaft 166, and the main shaft 170 of the motor 5 is positioned to overlap the circular saw blade P in the axial C direction view. This can suppress an increase in the size of the electric circular saw 100 in the vertical direction and the front-rear direction.

In addition, in the present embodiment, since the speed reduction 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 reduced.

In the present embodiment, the electric circular saws 1 and 100 are exemplified as the cutting machine, but the present invention is also applicable to a cutting machine of an electric tool driven by a motor other than the electric circular saw, for example, an electric saw or the like. From the viewpoint of assembling property, the belt may be stretched from one side by another power tool.

1-electric circular saw, 2-base, 3-shell, 4-cutting depth adjusting mechanism, 5-motor, 6-power transmission part, 7-belt contact limiting part.

Claims (15)

1. A cutting-off machine is characterized in that,

the disclosed device is provided with:

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 to have a larger diameter than the first pulley;

a first belt stretched between the first pulley and the second pulley and transmitting rotation of the first pulley to the second pulley;

a cutting blade for transmitting the rotation of the second belt pulley and rotating; and

an output shaft rotatably supported by the housing and to which the cutting blade is attached,

the material to be processed can be cut 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.

2. Cutting-off machine according to claim 1,

the disclosed device is provided with:

an intermediate shaft supported by the housing and supporting the second pulley;

a third pulley provided on the intermediate shaft, rotating about an axis of the intermediate shaft, having a smaller diameter than the second pulley, and rotating integrally with the second pulley;

a fourth pulley that is provided on the output shaft, is formed to have a diameter larger than the third pulley and smaller than the second pulley, and rotates integrally with the output shaft; and

a second belt stretched between the third pulley and the fourth pulley and transmitting rotation of the third pulley to the fourth pulley;

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.

3. Cutting-off machine according to claim 1 or 2,

in the axial view, the rotation center of the first pulley and the rotation center of the second pulley are located at positions overlapping the cutting blade.

4. Cutting-off machine according to claim 1 or 2,

and a base for supporting the housing and moving on the workpiece in the cutting direction to cut the workpiece,

the rotation center of the second pulley is located closer to the base than the rotation axis.

5. Cutting-off machine according to claim 2,

in the axial view, an inner angle formed by a first line segment and a second line segment in a triangle formed by a first line segment connecting an axis of the rotary shaft and an axis of the intermediate shaft, a second line segment connecting the axis of the intermediate shaft and an axis of the output shaft, and a third line segment connecting the axis of the rotary shaft and the axis of the output shaft is 90 degrees or less.

6. Cutting-off machine according to claim 5,

an inner angle formed by the second line segment and the third line segment in the triangle is 90 degrees or less.

7. A cutting-off machine according to claim 5 or 6,

the internal angles in the triangle are respectively 90 degrees or less.

8. Cutting-off machine according to claim 1 or 2,

further provided with:

a gear housing having a wall portion forming a recess portion recessed in an axial direction of the output shaft and accommodating the first belt and the second belt; and

a limiting wall for limiting the contact between the first belt and the second belt,

the motor is also provided with a motor main body part,

the second belt, the limiting wall, the first belt, the wall portion, and the motor main body portion are arranged in this order in the axial direction.

9. Cutting-off machine according to claim 2,

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 belts.

10. A cutting-off machine is characterized in that,

the disclosed device is provided with:

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, rotating about an axis of the driven shaft, and having a diameter larger than that of the first pulley;

a first belt stretched over the first pulley and the second pulley and transmitting rotation of the first pulley to the second pulley;

a cutting saw blade for transmitting the rotary force of the second belt wheel and rotating,

the cutter has a base supporting the housing and having a hole portion for projecting a part of the cutting blade downward, a rotation center of the cutting blade is located below a rotation center of the first pulley, and a rotation center of the second pulley is located above the rotation center of the first pulley.

11. Cutting-off machine according to claim 10,

the belt tensioner includes 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, and a rotational center of the fourth pulley is located below a rotational center of the second pulley.

12. Cutting-off machine according to claim 1 or 10,

when a direction orthogonal to the axial direction of the output shaft and the cutting direction is a vertical direction, the first pulley is positioned above a lower end and below an upper end of the second pulley.

13. Cutting-off machine according to claim 2 or 11,

when the cutting direction is set to the front-rear direction, the fourth pulley is positioned rearward of the front end of the second pulley and forward of the rear end.

14. A cutting-off machine is characterized in that,

the disclosed device is provided with:

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;

an intermediate shaft supported by the housing and supporting the second pulley;

a first belt stretched between the first pulley and the second pulley and transmitting rotation of the first pulley to the second pulley;

a third pulley provided on the intermediate shaft and rotating integrally with the second pulley;

an output shaft rotatably supported by the housing and to which a cutting blade can be attached;

a fourth pulley provided on the output shaft and rotating integrally with the output shaft; and

a second belt stretched between the third pulley and the fourth pulley and transmitting rotation of the third pulley to the fourth pulley,

the material to be processed can be cut by moving the cutting blade in the cutting direction,

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.

15. Cutting-off machine according to claim 14,

the second pulley is formed to have a larger diameter than the first pulley,

the third pulley is formed to have a smaller diameter than the second pulley,

the fourth pulley is formed to have a diameter larger than the third pulley and smaller than the second pulley.

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