Table saw and electric power tool

Abstract

The present invention provides a benchtop cutting machine and an electric cutting machine. The benchtop cutting machine (1) has a motor shaft (23a) of a motor (23), a first intermediate shaft (32), and an output shaft (37). The first intermediate shaft (32) rotates about an axis via the output of the motor shaft (23a). The output shaft (37) rotates the mounted cutting tool (11) by rotating about an axis via the output of the first intermediate shaft (32). A fan (24) is mounted on the first intermediate shaft (32). The fan (24) rotates about an axis together with the first intermediate shaft (32) to generate airflow to cool the motor (23) and the first intermediate shaft (32). Accordingly, it is possible to provide a structure that cools components other than the motor, such as the intermediate shaft, by means of a fan.

Description

Technical Field

[0001] This invention relates to a tabletop cutting machine and an electric cutting machine. Background Technology

[0002] As described in Patent Document 1, the tabletop cutting machine has a cutting machine body connected to a worktable in a tilting manner. The cutting machine body has a motor, the output of which is transmitted via an output shaft along a central axis. A saw blade, i.e., a cutting tool, mounted on the output shaft rotates together with the output shaft. A fan is mounted on the motor shaft. The air generated by the fan cools the motor and is exhausted from the motor housing.

[0003] [Existing technical documents] [Patent Literature]

[0004] Patent Document 1: Japanese Patent Publication No. 2023-102452 Summary of the Invention

[0005] [The technical problem that the invention aims to solve]

[0006] In the prior art, there is a need for a structure that uses a fan to cool components other than the motor, such as the intermediate shaft.

[0007] [Technical solutions used to solve technical problems]

[0008] According to one feature of the present invention, a benchtop cutting machine has a motor shaft, an intermediate shaft, and an output shaft. The intermediate shaft rotates about an axis via the output of the motor shaft. The output shaft rotates the mounted tool by rotating about an axis via the output of the intermediate shaft. A fan is mounted on the intermediate shaft. The fan rotates about an axis together with the intermediate shaft to generate airflow to cool the motor and the intermediate shaft. Therefore, the fan is mounted on the intermediate shaft, not the motor shaft. By mounting the fan on the intermediate shaft, the fan cools both the motor and the intermediate shaft. Furthermore, the airflow path extends along the power path including the intermediate shaft. Accordingly, the cooling effect can be improved by using a housing covering the power path. Additionally, one or more intermediate shafts can be provided between the motor shaft and the output shaft. Attached Figure Description

[0009] Figure 1 This is a perspective view of the benchtop cutting machine involved in the first embodiment, viewed from the right side.

[0010] Figure 2 This is a right view of a benchtop cutting machine with the main body of the cutting machine at the top dead center.

[0011] Figure 3This is a front view of a benchtop cutting machine with the main body of the cutting machine at the top dead center.

[0012] Figure 4 This is a right view of a benchtop cutting machine with the main body of the cutting machine at the bottom dead center.

[0013] Figure 5 This is a rear view of a benchtop cutting machine with the main body of the cutting machine at the top dead center.

[0014] Figure 6 This is a left view of a benchtop cutting machine with the main body of the cutting machine at the top dead center.

[0015] Figure 7 yes Figure 2 Section VII-VII.

[0016] Figure 8 yes Figure 2 Sectional view of VIII-VIII.

[0017] Figure 9 This is a three-dimensional view of the intermediate shaft housing viewed from the left.

[0018] Figure 10 This is a rear view of the fan.

[0019] Figure 11 This is a cross-sectional view of the reduced cross-section portion involved in the second embodiment.

[0020] Figure 12 This is a cross-sectional view of the reduced cross-section portion involved in the third embodiment.

[0021] Figure 13 This is a cross-sectional view of the main body of the cutting machine involved in the fourth embodiment.

[0022] Explanation of reference numerals in the attached figures 1: Tabletop cutting machine; 2: Base; 2a: Support; 3: Upper protrusion; 4: Rotary worktable; 4a: Upper surface of the worktable; 4b: Arm support; 5: Worktable extension; 5a: Slot; 5b: Blade plate; 6: Positioning baffle; 6a: Movable baffle; 6b: Positioning surface; 7: Angled dial; 7a: Fixing screw; 7b: Positioning recess; 8: Indicator; 9: Knob; 10: Cutting machine body; 10a: Up-and-down swing support shaft; 11: Blade 12: Fixed cover; 12a: Gear housing part; 12b: Hole; 12c: Hole; 12d: Gear housing connecting part; 13: Movable cover; 14: Fixing screw; 15: Outer flange; 16: Inner flange; 17: Lower dead center stop; 18: Upper dead center stop; 19: Lower dead center locking pin; 19a: Through hole; 20: Motor housing; 20a: Fixing screw; 20b: Hole; 20c: Hole; 23: Electric motor 23a: motor shaft; 23b: stator; 23c: rotor; 23d: commutator; 23e: first bearing; 23f: second bearing; 23g: air inlet; 24: fan; 24a: blade; 24b: inner circumference of blade; 24c: outer circumference of blade; 24d: inverted tilt section; 24e: length; X: radial region; Y: imaginary diameter; 30: power transmission section; 31: intermediate shaft housing; 31a: motor housing connection section; 31b: hub retaining section; 31c: retraction section 31d: Fan housing; 31e: Buffer section; 31f: Intermediate shaft housing; 31g: Fan housing; 31h: Hub; 32: First intermediate shaft; 32a: Upstream end; 32b: Upstream section; 32c: Downstream section (large diameter section); 32d: Small diameter section (reduced cross-section section); 32e: Rear inclined surface; 32f: Front inclined surface; 32g: Flange section; 32h: Third bearing; 32i: Fourth bearing; 32j: Gasket; 32n: Rear outlet; 32p: Left... Side outlet (outlet); 32r: Upper outlet; 32s: Downstream end; 32t: Driving side bevel gear; 32u: Snap ring; 32w: Shaft centerline; 33: Gear housing; 33a: Intermediate shaft housing connection; 33b: Fixing cover connection; 33c: Hole; 33d: Hole; 33e: Fixing screw; 33f: Fixing screw; 34: Bearing housing; 34a: Hole; 34b: Hole; 34c: Hole; 34d: Fixing screw; 35: Second intermediate shaft; 35a: From 35b: Reduction gear; 35c: 5th bearing; 35d: 6th bearing; 35e: Shim; 35f: Rubber ring; 35g: Shim; 35h: Retaining ring; 36: 3rd intermediate shaft; 36a: Idler gear; 36b: 7th bearing; 36c: 8th bearing; 37: Output shaft; 37a: Reduction gear; 37b: 9th bearing; 37c: 10th bearing; 40: Handle; 41: Operating handle; 42: Switch operating handle; 44: Lifting handle; 44a: 1st connecting part;44b: Second connecting part; 50: Main body support arm; 50a: Left and right tilting support shaft; 50b: Upper part; 51: Slide rod; 51a: First rod; 51b: Second rod; 52: Sliding base; 52a: Lower stop stop abutment part; 52b: Upper stop stop abutment part; 60: Rotary worktable fixing mechanism; 61: Handle part; 62: Fixing rod; 63: Forward locking mechanism; 64: Unlocking operation handle; 64a: Positioning pin; 65: Tilting fixing mechanism; 66: Tilting fixing operation part; 66a: Drive shaft; 67: Receiving part; 67a: Elongated hole; 70: First intermediate shaft; 71: Section reduction part; 72: First recess; 80: First intermediate shaft; 81: Section reduction part; 82: Second recess; 90: Cutting machine body; 91: Motor housing; 92: Electric motor 92a: Motor shaft; 92b: First bearing; 92c: Second bearing; 92d: First driving bevel gear; 93: Air inlet; 100: Power transmission unit; 101: Intermediate shaft housing; 102: Gear housing; 103: Third bearing; 104: Fourth bearing; 105: Fifth bearing; 106: Sixth bearing; 107: Fan housing; 108: Exhaust outlet; 110: First intermediate shaft; 111: First driven bevel gear; 112: Second driving bevel gear; 120: Second intermediate shaft; 121: Second driven bevel gear; J: Motor axis; S1: Imaginary orthogonal plane; T: Rotation direction; R: Radius. Detailed Implementation

[0023] According to another feature of the invention, the intermediate shaft is directly connected to the motor shaft, or rotates about the axis at the same speed as the motor shaft. That is, the intermediate shaft is positioned near the motor. For example, the intermediate shaft is connected to the motor shaft without the need for a reduction gear or the like. Therefore, a fan located on the intermediate shaft can also effectively cool the relatively nearby motor.

[0024] According to another feature of the invention, the intermediate shaft has an upstream end that receives the output from the motor shaft and a downstream end that transmits the output to the output shaft. The fan is located at the downstream end, closer to the center of the intermediate shaft along its length. Therefore, air from the motor reaches the fan through most of the intermediate shaft. Accordingly, the intermediate shaft can be effectively cooled.

[0025] According to another feature of the invention, the axial length of the fan is longer than one-quarter of the fan's diameter. That is, the axial length of the fan is longer, and the diameter is smaller. Therefore, it is possible to reduce the diameter of the intermediate shaft housing that houses the fan and the intermediate shaft without reducing the airflow generated by the fan.

[0026] According to another feature of the invention, the center line of the intermediate shaft is located on an imaginary orthogonal plane orthogonal to the output shaft, or inclined at less than 10° relative to the imaginary orthogonal plane. When the tool is a saw blade, the intermediate shaft is arranged substantially parallel to the disc surface of the saw blade. Therefore, the size of the cutting machine body in the output shaft direction is avoided.

[0027] According to another feature of the invention, the motor shaft and the intermediate shaft are coaxially configured. Therefore, the housing covering the motor shaft and the intermediate shaft can be reduced radially. Alternatively, the airflow from the cooling fan and the intermediate shaft flows in a generally straight line. Therefore, a decrease in airflow can be suppressed.

[0028] According to another feature of the invention, the motor is housed in a motor housing made of synthetic resin. The intermediate shaft is housed in an intermediate shaft housing made of lightweight metal. Therefore, the insulation of the conductive parts surrounding the motor can be ensured by the motor housing. Furthermore, the heat generated in the intermediate shaft can be transferred to the lightweight metal intermediate shaft housing and cooled.

[0029] According to another feature of the invention, when viewed from the axial direction (i.e., side view) of the output shaft, the fan is configured to overlap with the saw blade, which serves as the cutting tool. Therefore, the fan can be installed within the space surrounding the relatively large saw blade. Consequently, the cutting machine can be miniaturized.

[0030] According to another feature of the invention, the motor is an AC motor. Compared to a DC motor, an AC motor generates more heat and has a larger volume. Therefore, according to this feature, cooling efficiency can be significantly improved, and miniaturization can also be significantly achieved.

[0031] According to another feature of the invention, there are two bearings that support the intermediate shaft in a manner rotatable about an axis. The fan is located between the two bearings. Therefore, the two bearings, together with the intermediate shaft, stably support the fan.

[0032] According to another feature of the invention, a fan housing section is provided, which houses a fan. An intermediate shaft housing section with a smaller cross-sectional area than the fan housing section is also provided. The intermediate shaft housing section houses a portion of the intermediate shaft upstream of the fan. A buffer section is provided, which includes a step created due to the difference in cross-sectional areas between the intermediate shaft housing section and the fan housing section. Therefore, the airflow passes through the smaller cross-sectional area intermediate shaft housing section and reaches the larger cross-sectional area fan housing section. Then, the airflow is dispersed near the fan by the buffer section. Accordingly, the airflow can flow smoothly.

[0033] According to another feature of the invention, the fan has blades extending radially. The blades have an inner circumferential portion that protrudes in the direction of rotation on the inner circumferential side. The blades also have an outer circumferential portion that protrudes in the direction opposite to the direction of rotation on the outer circumferential side. With this structure, the blades can generate a strong wind.

[0034] According to another feature of the invention, the outer periphery of the blade has an inverted inclined portion extending radially outward from the bottom of the recess in the direction of rotation. The inverted inclined portion is located radially outward at a position approximately half the radius of the fan. Therefore, the inverted inclined portion is located only in the outer periphery of the fan. Accordingly, the fan can effectively generate airflow.

[0035] According to another feature of the invention, the outer periphery of the blade has an inverted inclined portion extending radially outward from the bottom of the recess in the direction of rotation. The inverted inclined portion is located radially outward from the midpoint of the radial length of the blade. Therefore, the inverted inclined portion is located only in the outer periphery of the fan. Accordingly, the fan can effectively generate airflow.

[0036] According to another feature of the invention, the extending direction of the outer peripheral end of the inclined portion is inclined at 30° to 60° relative to the radial line of the fan. With this structure, the blades can effectively generate wind.

[0037] Another feature of the invention is that it includes a fixed cover for the cutting tool and a fan housing for housing the fan. An outlet is provided in the fan housing. The outlet opens into the fixed cover. Therefore, air is discharged from the fan housing into the fixed cover. Thus, it is possible to suppress or reduce the amount of air blowing directly onto the operator.

[0038] According to another feature of the invention, the electric work machine has a motor shaft and an intermediate shaft. The intermediate shaft is coaxially configured with the motor shaft and rotates about the axis via the output of the motor shaft. A fan is mounted on the intermediate shaft. The fan rotates together with the intermediate shaft about the axis to generate airflow to cool the motor and the intermediate shaft.

[0039] Therefore, the fan is mounted on the intermediate shaft, not the motor shaft. By mounting the fan on the intermediate shaft, the fan cools both the motor and the intermediate shaft. Furthermore, by using the intermediate shaft, the motor shaft can be shortened, thereby reducing the size of the motor housing. Alternatively, the airflow path can be extended along the power path, including the intermediate shaft. Accordingly, a housing covering the power path can be used to improve cooling efficiency.

[0040] according to Figures 1-10 The first embodiment of the present invention will be described below. In this embodiment, a tabletop cutting machine 1, known as a so-called sliding circular saw, is exemplified. Figure 1As shown, the benchtop cutting machine 1 includes: a base 2, which is placed on a table, the ground, etc.; a rotating worktable 4, which is used to hold the workpiece to be cut; and a cutting machine body 10. The rotating worktable 4 is supported on the base 2 in a manner that allows it to rotate horizontally. The cutting machine body 10 is positioned above the rotating worktable 4. A generally circular blade (circular saw blade) 11, called a tipped saw blade, is rotatably supported on the cutting machine body 10. The user performs the cutting operation near the benchtop cutting machine 1. In the following description, the front-to-back direction is defined as the direction closest to the user's viewpoint. The up-down and left-right directions are defined based on the user.

[0041] like Figure 1 As shown, the rotary table 4 is roughly circular when viewed from above, and its upper surface 4a is horizontally positioned. The base 2 has upper protrusions 3 at both ends, and the rotary table 4 is supported horizontally in the space between the upper protrusions 3. Furthermore, in this embodiment, a larger rotary table 4 than usual is used, and the left and right ends of the base 2 do not have mounting surfaces for placing the workpiece to be cut. A pair of supports 2a, 2a are respectively installed on the left and right sides of the base, and the upper surfaces of the supports 2a, 2a function as auxiliary worktables. The rotary table 4 has a table extension 5 extending forward along the side of the tool 11. A notch-shaped slot 5a extending along the side of the tool 11 is provided in the center of the upper surface of the table extension 5. A cutting edge plate 5b is provided above the slot 5a.

[0042] like Figure 1 As shown, a wall-shaped positioning baffle 6 extending horizontally and upwards is provided above the rotary table 4 and the upper protrusion 3. The positioning baffle 6 is supported by the left and right upper protrusions 3. The front surface of the positioning baffle 6, i.e., the positioning surface 6b, is located on a vertical plane passing through the rotation center of the rotary table 4. The workpiece to be cut, placed on the rotary table 4, is positioned in the front-rear direction by abutting against the positioning surface 6b. Above the positioning baffle 6, a pair of movable baffles 6a, 6a are provided, which can extend the positioning surface 6b upwards. The movable baffles 6a, 6a can slide in the left-right direction, and if their position is located in a position that would cause interference when the cutting machine body 10 is tilted, they can be avoided by sliding outwards.

[0043] like Figure 1 , Figure 2As shown, a miter scale plate 7 in the shape of an arc is provided in approximately half of the front portion of the base 2. The miter scale plate 7 extends horizontally below the upper surface 4a of the worktable. The miter scale plate 7 cooperates with indicators 8 provided on the left and right sides of the rotary worktable 4 to display the rotation angle of the rotary worktable 4. The rotation angle of the rotary worktable 4 is the angle formed by the tool 11 and the imaginary surface orthogonal to the positioning surface 6b of the positioning baffle 6. When this angle is 0 degrees, the workpiece can be cut at a right angle to the length direction of the workpiece. This cut is called a cross cut. By rotating the rotary worktable 4 to the left or right, the tool 11 can be tilted relative to the imaginary surface orthogonal to the positioning surface 6b of the positioning baffle 6. Cutting the workpiece with the tool 11 in this posture is called a miter cut. Multiple radially extending groove-shaped positioning recesses 7b are provided on the miter scale plate 7. Positioning recesses 7b are spaced at predetermined angles along the circumference of the angled dial 7. The tip of the positioning pin 64a (described later) can enter the positioning recesses 7b. The angled dial 7 is fixed to the base 2 by multiple fixing screws 7a. The fixing screws 7a are inserted into elongated holes that pass through the angled dial 7 in the vertical direction. By loosening the fixing screws 7a, the angle between the positioning baffle 6 and the tool 11 can be finely adjusted by moving the angled dial 7 in the left-right direction. For example, as long as the positioning pin 64a is inserted into the positioning recess 7b at a right angle, the right angle between the tool 11 and the positioning baffle 6 can be precisely adjusted. This adjustment is mainly performed during the product manufacturing process.

[0044] like Figure 1 As shown, a generally cylindrical arm support 4b with the front-to-back direction as the axial direction is provided at the rear of the rotary table 4. A main support arm 50 extending generally upward is provided behind the arm support 4b. The main support arm 50 is supported such that it can tilt in the left-to-right direction relative to the arm support 4b, centered on a left-to-right tilting pivot 50a extending in the front-to-back direction. When the cutter 11 is perpendicular, the main support arm 50 tilts generally to the right as it moves upward. The upper part 50b of the main support arm 50 is shaped to retract from the movable area of ​​the cutting machine body 10 when the sliding base 52 (described later) is moved to the rear end.

[0045] The main support arm 50 can tilt to the left and right, respectively, up to 45° around the left and right tilting pivot 50a. Furthermore, by switching the tilting positioning mechanism (located at the rear of the main support arm 50, but omitted from the figure for convenience), it can tilt up to a maximum of 48°. Therefore, the cutter 11 can also tilt to the left and right, respectively, up to a maximum of 48° around the left and right tilting pivot 50a. By tilting the cutter 11 to the left and right, a bevel cut can be performed on the workpiece placed on the rotary table 4.

[0046] like Figure 1 As shown, an elongated slide bar 51, parallel to the side of the cutter 11 and extending horizontally, is mounted on the upper part 50b of the main support arm. The slide bar 51 has a first upper rod 51a and a second lower rod 51b arranged side by side in the vertical direction. The first rod 51a is, for example, formed into a cylindrical shape. The second rod 51b is, for example, formed into a cylindrical shape with a diameter larger than that of the first rod 51a. A sliding base 52 is mounted on the first rod 51a and the second rod 51b in a manner that allows it to slide in the front-back direction. The cutting machine body 10 is connected to the left side of the sliding base 52. Therefore, when the cutter 11 is in a vertical position, the cutting machine body 10 is located to the left of the first rod 51a and the second rod 51b. By sliding the sliding base 52 in the front-back direction, it is possible to cut, for example, a wide workpiece placed on the rotary table 4. A knob 9 is provided on the upper surface of the sliding base 52. By rotating the knob 9 in the tightening direction, the sliding base 52, which slides relative to the slide bar 51, can be fixed in any position.

[0047] like Figure 2 , Figure 4 As shown, the cutting machine body 10 can swing vertically relative to the sliding base 52 with a vertical swing support 10a extending in the left-right direction as the center. The vertical swing support 10a is located behind the cutter 11. By swinging the cutting machine body 10 downward, the cutter 11 can cut into the workpiece placed on the rotary table 4. With the bottom dead center set to 0°, the top dead center of the vertical swing angle of the cutting machine body 10 is 52°. In other words, the cutting machine body 10 can swing vertically within an angle range of 52°. A torsion spring is provided around the vertical swing support 10a to apply an upward force to the cutting machine body towards the top dead center.

[0048] like Figure 2 , Figure 4 As shown, the cutting machine body 10 has a fixed cover 12 and a movable cover 13 covering the cutting tool 11. The fixed cover 12 covers the upper half-circumference of the cutting tool 11 from the left and right sides and radially outward. The movable cover 13 covers the lower half-circumference of the cutting tool 11. The movable cover 13 rotates in conjunction with the up-and-down swing of the cutting machine body 10, opening and closing the lower half-circumference of the cutting tool 11. When the cutting machine body 10 swings upward, the movable cover 13 moves towards the closed position ( Figure 2 The middle part rotates counterclockwise. Therefore, when the cutting machine body 10 is at the top dead center, the lower half-circumference of the cutter 11 is covered. When the cutting machine body 10 is swung downwards, the movable cover 13 moves towards the open position (where the middle part rotates counterclockwise). Figure 4(Rotating clockwise). As a result, the lower half of the circumference of the tool 11 is exposed, thereby enabling the tool 11 to cut into the workpiece placed on the rotary table 4.

[0049] like Figure 7 , Figure 8 As shown, the cutter 11 is integrally mounted on the output shaft 37, which extends in the left-right direction and is rotatably supported on the cutting machine body 10. The cutter 11 rotates about the output shaft 37. The cutter 11 is mounted on the output shaft 37 by screwing in the fixing screw 14 while it is held by the outer flange 15 and the inner flange 16 at the center of rotation.

[0050] like Figure 5 As shown, a lower stop stop 17 is provided on the right side of the cutting machine body 10. The lower stop stop 17 has a bolt that is threaded into the cutting machine body 10 and protrudes downward. For example, the protruding length of the lower stop stop 17 can be changed by inserting a hexagonal wrench into the hexagonal hole of the bolt head and rotating it. Accordingly, the position of the lower stop of the cutting machine body 10 can be finely adjusted. A lower stop stop abutment portion 52a is provided on the front surface of the sliding base 52. When the cutting machine body 10 is lowered to the lower stop, the lower stop stop abutment portion 52a abuts against the top end of the lower stop stop 17 (see reference). Figure 4 The lower stop stop abutment portion 52a is a plane provided on the upper surface of the protrusion that protrudes forward from the front surface of the sliding base 52.

[0051] like Figure 5 , Figure 6 As shown, a top stop stop 18 protruding to the left is provided on the left side of the fixed cover 12. On the upper surface of the left side of the sliding base 52, a planar top stop stop abutment part 52b is provided, which can abut against the top stop stop 18. By abutting against the top stop stop 18 and the top stop stop abutment part 52b, the upward movement of the cutting machine body 10 stops at the top stop.

[0052] like Figure 6 As shown, a lower stop locking pin 19 extending to the left is provided on the left side of the front part of the sliding base 52. On the fixed cover 12, a through hole 19a extending in the left-right direction is provided in front of the upper stop stop 18. When the cutting machine body 10 moves to the lower stop, the lower stop locking pin 19 can move to the right and enter the through hole 19a. By pressing the left end of the lower stop locking pin 19 to the right to make it enter the through hole 19a, the cutting machine body 10 can be locked at the lower stop.

[0053] like Figure 2 , Figure 4As shown, the cutting machine body 10 has a motor housing 20 between the cutter 11 and the slide bar 51 in the left-right direction. The motor housing 20 is made of synthetic resin. The motor 23 is housed in the motor housing 20. A motor shaft 23a is provided at the center of the motor 23. The motor shaft 23a extends in the front-rear direction along a motor axis J parallel to the side of the cutter 11.

[0054] like Figure 7 As shown, the motor 23 is a brushed AC motor powered by AC electricity. The motor shaft 23a is supported by a first bearing 23e and a second bearing 23f, enabling it to rotate about the motor axis J. The inner ring of the first bearing 23e is pressed into the rear end of the motor shaft 23a, and the outer ring is pressed into a hole located at the inner rear end of the motor housing 20. The inner ring of the second bearing 23f is pressed into the front of the motor shaft 23a, and the outer ring is pressed into a hole 20b located in the hub retaining portion 31b (described later).

[0055] like Figure 7 As shown, the stator 23b of the motor 23 is supported on the inner circumferential surface of the motor housing 20 in a non-rotatable manner. The rotor 23c of the motor 23 is disposed on the inner circumferential side of the stator 23b. The rotor 23c is mounted along the outer circumference of the motor shaft 23a and is capable of rotating with the motor shaft 23a. A commutator 23d is mounted behind the rotor 23c. An air inlet 23g for drawing in external air is provided on the rear surface of the motor housing 20.

[0056] like Figure 2 The cutting machine body 10 has a power transmission unit 30 between the cutter 11 and the slide bar 51 in the left-right direction, which transmits the driving force of the motor shaft 23a to the output shaft 37. The power transmission unit 30 is housed in an intermediate shaft housing 31 and a gear housing 33, and is located in a gear receiving portion 12a on the right side of the fixing cover 12. The intermediate shaft housing 31 is connected to the opening at the front end of the motor housing 20. The gear housing 33 connects the opening at the front end of the intermediate shaft housing 31 and the opening at the right end of the gear receiving portion 12a.

[0057] like Figure 7 As shown, the intermediate shaft housing 31 is a generally cylindrical shape extending toward the side of the cutter 11. The intermediate shaft housing is formed by the motor housing connecting part 31a, the hub retaining part 31b, the reduction housing 31c, and the fan housing 31d arranged along the motor axis J. The motor housing connecting part 31a is connected to the front end of the motor housing 20 by multiple fixing screws 20a (see reference). Figure 2 The fan housing 31d is connected to the intermediate shaft housing connection part 33a at the rear end of the gear housing by multiple fixing screws 33e extending along the motor axis J.

[0058] In the intermediate shaft housing 31, the motor housing connecting portion 31a has the largest cross-sectional area orthogonal to the front-rear direction. The cross-sectional area of ​​the intermediate shaft housing 31 gradually decreases from the motor housing connecting portion 31a to the reduced-size housing 31c. The cross-sectional area of ​​the fan housing 31d is larger than that of the hub retaining portion 31b and smaller than that of the motor housing connecting portion 31a. The fan housing 31d has a wall-shaped buffer portion 31e, which rises vertically outward from the reduced-size housing 31c.

[0059] like Figure 7 As shown, a first intermediate shaft 32, which is linear and elongated, is housed in an intermediate shaft housing 31. The first intermediate shaft 32 is coaxially configured with a motor shaft 23a. The outer peripheral surfaces of the front end of the motor shaft 23a and the rear upstream end 32a of the first intermediate shaft 32 are splined. The front end of the motor shaft 23a and the rear upstream end 32a of the first intermediate shaft 32 are inserted into a hub 31h, whose inner peripheral surface is splined, thereby being connected in a way that can transmit rotational power. The first intermediate shaft 32 has a rear upstream portion 32b, a front downstream portion 32c, and a cross-sectional reduction portion 32d located between the upstream portion 32b and the downstream portion 32c. The cross-sectional reduction portion 32d is housed in an intermediate shaft housing portion 31f within a reduction portion housing 31c. The radial cross-sectional area of ​​the cross-sectional reduction portion 32d is smaller than that of the upstream portion 32b and the downstream portion 32c. When viewed from the side, the cross-sectional reduction portion 32d is configured to overlap with the tool 11. In the first embodiment, the cross-sectional reduction portion 32d is formed as a small-diameter portion 32d that is reduced in diameter throughout its circumference. Because its cross-sectional area is smaller than other portions, the small-diameter portion 32d is prone to elastic deformation. When a load is applied, such as braking force, the small-diameter portion 32d actively twists. Accordingly, the small-diameter portion 32d functions as a torsion bar, mitigating impacts on the gears.

[0060] like Figure 7As shown, a rearward inclined surface 32e, which gradually decreases in size radially forward, is formed on the outer peripheral surface between the upstream portion 32b and the small-diameter portion 32d. The rearward inclined surface 32e extends in a straight line when viewed from the radially outer side. A forward inclined surface 32f, which gradually increases in size radially forward, is formed on the outer peripheral surface between the small-diameter portion 32d and the downstream portion 32c. The forward inclined surface 32f extends in a curved surface when viewed from the radially outer side. The forward inclined surface 32f changes abruptly relative to the outer peripheral surface of the downstream portion 32c. The downstream portion 32c has a flange portion 32g that protrudes radially outward in a flange-like manner from a portion thereof. The ratio of the diameter of the small-diameter portion 32d to the diameter of the downstream portion 32c, excluding the flange portion 32g, is 30% to 80%. For example, if the diameter of the downstream portion 32c is 15 mm relative to the diameter of the small-diameter portion 32d, then 8 mm / 15 mm = 0.53 (53%). Furthermore, the ratio of the diameter to the length (diameter / length) of the minor diameter portion 32d is 5% to 40%. For example, if the diameter of the minor diameter portion 32d is 8 mm and its length is 62 mm, then 8 mm / 62 mm = 0.129 (12.9%). Additionally, the ratio of the diameter of the minor diameter portion 32d to the diameter of the upstream end portion 32a is 50% to 90%. For example, if the diameter of the minor diameter portion 32d is 8 mm and its diameter is 10.8 mm, then 8 mm / 10.8 mm = 0.74 (74%).

[0061] The first intermediate shaft 32 is made of mechanical structural alloy steel such as chromium-molybdenum steel (SCM material) or nickel-chromium-molybdenum steel (SNCM material). For example, chromium-molybdenum steel is used. The upstream portion 32b and the downstream portion 32c are heat-treated. The small-diameter portion 32d is not heat-treated. As a result, the hardness of the small-diameter portion 32d is lower, and the small-diameter portion 32d is more prone to elastic deformation.

[0062] like Figure 7 As shown, the first intermediate shaft 32 is supported by the third bearing 32h and the fourth bearing 32i, enabling it to rotate about the motor axis J. The inner ring of the third bearing 32h is pressed into the upstream portion 32b of the first intermediate shaft 32, and the outer ring is pressed into the hole 20c provided in the hub retaining portion 31b. The inner ring of the fourth bearing 32i is pressed into the downstream portion 32c of the first intermediate shaft 32, and the outer ring is pressed into the hole 33c provided in the intermediate shaft housing connecting portion 33a. The fourth bearing 32i is prevented from disengaging from the hole 33c by a shim 32j. The second bearing 23f and the third bearing 32h are both positioned in the holes 20b and 20c provided in the hub retaining portion 31b, thereby enabling high-precision positioning of the motor shaft 23a and the first intermediate shaft 32.

[0063] like Figure 7As shown, a fan 24 is mounted between the small-diameter portion 32d and the downstream portion 32c of the first intermediate shaft 32, in a manner that allows it to rotate integrally with the first intermediate shaft 32. The fan 24 is housed within a fan housing 31g inside a fan housing 31d. When the fan 24 is rotated by the drive motor 23, cooling air is introduced into the intermediate shaft housing 31 through the motor housing 20 from the air inlet 23g. The air flowing into the intermediate shaft housing 31 passes from the intermediate shaft housing 31f, which has a smaller cross-sectional area, to the fan housing 31g, which has a larger cross-sectional area. Accordingly, the air is dispersed near the fan 24 by the buffer portion 31e. Then, the air is discharged from a plurality of outlets 32n, 32p, and 32r provided in the fan housing 31d. The cooling air cools the motor 23 and the first intermediate shaft 32.

[0064] like Figure 9 As shown, the outlet of the gear housing connection has a rear outlet 32n that opens rearward from the lower part of the buffer portion 31e. The rear outlet 32n is formed by elongated holes that are thin in the vertical direction and arranged in the horizontal direction. In addition, the outlet has a left outlet 32p that opens larger to the left. The left outlet 32p exhausts air into the fixed cover 12. In addition, the outlet has an upper outlet 32r that opens larger upward.

[0065] like Figure 10 As shown, fan 24 has blades 24a extending radially from the center of rotation. Fan 24 is arranged in... Figure 10 The direction shown is counterclockwise rotation. Blade 24a has an inner circumferential portion 24b that protrudes in the rotational direction T on the inner circumferential side, and an outer circumferential portion 24c that protrudes in the opposite direction to the rotational direction T on the outer circumferential side. When fan 24 rotates, the recess in the outer circumferential portion 24c draws in air to generate wind. Therefore, a stronger wind can be generated. The inner circumferential portion 24b and the outer circumferential portion 24c are formed in such a way that they substantially divide the radial region X of blade 24a into two parts. The outer circumferential portion 24c has an inverted inclined portion 24d that extends radially outward from the bottom of the recess in the rotational direction T. The inverted inclined portion 24d is formed radially outward from approximately the center of the outer circumferential portion 24c. The inverted inclined portion 24d is formed at a position more than halfway outward from the radius R of fan 24. The extending direction of the outer circumferential end of the inverted inclined portion 24d is inclined, for example, at 45° relative to the imaginary radial line Y of fan 24. The angle Q of the inverted tilt 24d relative to the imaginary radial line Y is expected to be between 30° and 60°. Additionally, the axial length 24e of the fan 24 (refer to...) Figure 7 It is longer than 1 / 4 of the diameter of fan 24. The diameter of fan 24 is, for example, 68mm.

[0066] like Figure 7As shown, a drive side bevel gear 32t is integrally mounted at the downstream end 32s in front of the first intermediate shaft 32. A retaining ring 32u for preventing disengagement is mounted in front of the drive side bevel gear 32t. The drive side bevel gear 32t enters the gear housing 33.

[0067] like Figure 7 , Figure 8 As shown, the gear housing 33 is configured such that the intermediate shaft housing connecting portion 33a and the fixed cover connecting portion 33b are internally connected, wherein the intermediate shaft housing connecting portion 33a opens rearward at the rear end; and the fixed cover connecting portion 33b opens to the left at the left side. The gear receiving portion 12a of the fixed cover 12 is configured such that the gear housing connecting portion 12d and the opening of the output shaft 37 protruding to the left of the cutter 11 are internally connected, wherein the gear housing connecting portion 12d opens to the right at the right end. The fixed cover connecting portion 33b is sleeved onto the outer periphery of the gear housing connecting portion 12d. The fixed cover connecting portion 33b and the gear housing connecting portion 12d are connected by multiple fixing screws 33f extending in a direction substantially orthogonal to the side of the cutter 11 (see reference). Figure 2 ).

[0068] like Figure 8 As shown, the second intermediate shaft 35, the third intermediate shaft 36, and the output shaft 37 are supported on the gear housing 33 and the gear receiving portion 12a in a manner rotatable about their axes. The second intermediate shaft 35, the third intermediate shaft 36, and the output shaft 37 are orthogonal to the side of the cutter 11 and extend in the left-right direction. The bearing housing 34 is connected to the left side of the gear housing 33 by multiple fixing screws 34d extending in a direction approximately orthogonal to the side of the cutter 11. The bearing housing 34 holds the bearings that support the second intermediate shaft 35, the third intermediate shaft 36, and the output shaft 37 respectively.

[0069] like Figure 8 As shown, the second intermediate shaft 35 is rotatably supported by the fifth bearing 35c and the sixth bearing 35d. The inner ring of the fifth bearing 35c is pressed into the right end of the second intermediate shaft 35, and the outer ring is pressed into the hole 33d located on the right side of the gear housing 33. The inner ring of the sixth bearing 35d is pressed into the left end of the second intermediate shaft 35, and the outer ring is pressed into the hole 34a located in the bearing housing 34. The fourth bearing 32i and the fifth bearing 35c are both positioned in the holes 33c and 33d located in the gear housing 33, thereby enabling high-precision positioning of the first intermediate shaft 32 and the second intermediate shaft 35. Furthermore, it enables high-precision meshing of the driving bevel gear 32t and the driven bevel gear 35a.

[0070] like Figure 8As shown, the driven bevel gear 35a is inserted into the right side of the second intermediate shaft 35 in an axially movable manner with an overfit. The driven bevel gear 35a and the second intermediate shaft 35 are prevented from rotating relative to each other by a key and keyway fit. On the right side of the driven bevel gear 35a, steel shims 35e, rubber rings 35f, and steel shims 35g are installed on the second intermediate shaft 35. A retaining ring 35h is installed on the rubber ring 35f, sandwiched between shims 35e and 35g, in an axially crushed state. The rubber ring 35f buffers impacts and vibrations between the second intermediate shaft 35 and the driven bevel gear 35a. The driven bevel gear 35a meshes with the driving bevel gear 32t. The rotational power of the first intermediate shaft 32 is transmitted to the second intermediate shaft 35 after deceleration and when the rotation direction becomes approximately perpendicular, through the meshing of the driving bevel gear 32t and the driven bevel gear 35a. Between the driven bevel gear 35a and the sixth bearing 35d in the left-right direction, the reduction gear 35b and the second intermediate shaft 35 are formed as an integral part.

[0071] like Figure 8 As shown, the third intermediate shaft 36 is rotatably supported by the seventh bearing 36b and the eighth bearing 36c. The inner ring of the seventh bearing 36b is pressed into the right end of the third intermediate shaft 36, and the outer ring is pressed into the hole 12b located on the right side of the gear housing 12a. The inner ring of the eighth bearing 36c is pressed into the left end of the third intermediate shaft 36, and the outer ring is pressed into the hole 34b located in the bearing housing 34. Between the seventh bearing 36b and the eighth bearing 36c in the left-right direction, the idler gear 36a is integrally formed with the third intermediate shaft 36. The idler gear 36a meshes with the reduction gear 35b. The rotational power of the second intermediate shaft 35 is transmitted to the third intermediate shaft 36 after deceleration through the meshing of the reduction gear 35b and the idler gear 36a.

[0072] like Figure 8 As shown, the output shaft 37 is rotatably supported by the 9th bearing 37b and the 10th bearing 37c. The inner ring of the 9th bearing 37b is pressed into the right end of the output shaft 37, and the outer ring is pressed into the hole 12c located on the right side of the gear housing 12a. The inner ring of the 10th bearing 37c is pressed into the center of the output shaft 37, and the outer ring is pressed into the hole 34c located in the bearing housing 34. Between the 9th bearing 37b and the 10th bearing 37c in the left-right direction, the reduction gear 37a is integrally formed with the output shaft 37. The reduction gear 37a meshes with the idler gear 36a. The rotational power of the third intermediate shaft 36 is transmitted to the output shaft 37 after being accelerated through the meshing of the idler gear 36a and the reduction gear 37a. The output shaft 37 is decelerated relative to the second intermediate shaft 35 according to the gear ratio of the reduction gear 35b and the reduction gear 37a. The third intermediate shaft 36 is only equipped with an idler wheel 36a; therefore, its purpose is to increase the axial distance between the second intermediate shaft 35 and the output shaft 37. In this way, the motor shaft 23a (refer to...) Figure 7 The rotational power of the tool 11 is transmitted to the output shaft 37 after deceleration, thereby causing the tool 11 to rotate.

[0073] like Figure 2 , Figure 4 As shown, with the cutter 11 vertical, regardless of the position of the cutting machine body 10 from the top dead center to the bottom dead center, the motor 23 is positioned above the first lever 51a. With the cutter 11 vertical, when the cutting machine body 10 is at the top dead center, the first intermediate shaft 32 is positioned above the first lever 51a. With the cutter 11 vertical, when the cutting machine body 10 is at the bottom dead center, the first intermediate shaft 32 overlaps with the slide bar 51 in the vertical direction. With the cutter 11 vertical and the cutting machine body 10 at the top dead center, the opposite side of the gear side of the motor shaft 23a is inclined upwards relative to the horizontal line. Accordingly, the motor housing 20 overlaps with the first lever 51a and the upper part 50b of the main support arm in the vertical direction. With the cutting machine body 10 at the top dead center, the motor shaft 23a is positioned entirely behind the vertical swing support shaft 10a.

[0074] like Figure 7 As shown, the motor shaft 23a extends parallel to the side of the cutter 11. The angle formed by the motor shaft 23a and the side of the cutter 11, when viewed from the extension direction of the cutter 11 or the radial direction of the motor shaft 23a, is preferably -10° to 0° to 10° (based on the opposite side of the gear side of the motor shaft 23a being parallel to the cutter (0°), with leftward tilt being positive and rightward tilt being negative). Within this angle range, only the shaft angles of the meshing driving bevel gear 32t and driven bevel gear 35a need to be adjusted, without requiring major changes to the design concept such as adding additional components. Furthermore, since the first intermediate shaft 32 is coaxial with the motor shaft 23a, the first intermediate shaft 32 also extends parallel to the side of the cutter 11. That is, the axis centerline 32w of the first intermediate shaft 32 is parallel to the imaginary orthogonal plane S1, which is orthogonal to the output shaft 37. The angle formed by the axis centerline 32w and the imaginary orthogonal plane S1 is preferably -10° to 0° to 10°.

[0075] like Figure 3 As shown, with the cutter 11 in a vertical position, the cutting machine body 10 has a handle portion 40 located to the right of the side of the cutter 11 and in front of the gear housing 33. A ring-shaped operating handle 41 extending in a left-right direction approximately orthogonal to the side of the cutter 11 is provided at the front of the handle portion 40. A switch operating handle 42 is provided on the inner circumference of the operating handle 41. The switch operating handle 42 can be activated by hooking it with a finger while the user is holding the operating handle 41. When the switch operating handle 42 is activated, the motor 23 starts, causing the cutter 11 to rotate.

[0076] like Figure 2 , Figure 4 As shown, the handle portion 40 has a handle 44 behind the operating handle 41. The handle 44 is annular, with a first connecting portion 44a at one end and a second connecting portion 44b at the other end. The first connecting portion 44a is connected to the rear of the operating handle 41, which extends to the right side of the fixed cover 12. The second connecting portion 44b is connected to the upper part of the motor housing 20. When the cutter is in a vertical position, the handle 44 extends along the motor shaft 23a in the front-rear direction. When the cutting machine body 10 is moved to the lower dead center, the handle 44 extends approximately horizontally. With the cutting machine body 10 locked at the lower dead center by the lower dead center locking pin 19, the user can move the benchtop cutting machine 1 by holding the handle 44.

[0077] like Figure 1 , Figure 2 As shown, a rotary table fixing mechanism 60 is provided at the lower part of the worktable extension 5. A handle 61 is provided at the front of the worktable extension 5. The periphery of the handle 61 has a concave-convex shape so that the user can easily grip and rotate it. The user can grip the handle 61 and rotate the rotary table 4 horizontally relative to the base 2. A fixing rod 62 extends from the handle 61 toward the rear interior of the worktable extension 5 in the front-rear direction. The fixing rod 62 is supported inside the worktable extension 5 by a threaded engagement. The handle 61 can rotate about the fixing rod 62 as its axis. When the handle 61 is rotated about the axis of the fixing rod 62, the fixing rod 62 is displaced in the front-rear direction. By displacing the fixing rod 62 rearward, its rear end engages with the base 2, allowing the rotary table 4 to be positioned at any angle on the base 2. By displacing the fixing rod 62 forward, the positioning of the rotary table 4 at any angle can be released.

[0078] like Figure 1 As shown, a forward locking mechanism 63 is provided at the lower part of the worktable extension 5. By using the forward locking mechanism 63, the rotating worktable 4 can be positioned at a predetermined angle corresponding to the positioning recess 7b of the inclined dial 7. The forward locking mechanism 63 is provided with an unlocking operating handle 64 and a positioning pin 64a. The unlocking operating handle 64 is located rearward and lower than the grip portion 61 at the front of the worktable extension 5. The positioning pin 64a extends in the front-rear direction along the length of the worktable extension 5 at the lower part of the worktable extension 5. The positioning pin 64a is located at approximately the same height as the inclined dial 7. The rear end of the positioning pin 64a can be disengaged from the positioning recess 7b by rearward displacement. Furthermore, the rear end of the positioning pin 64a can be disengaged from the positioning recess 7b by forward displacement.

[0079] Figure 2The front part of the positioning pin 64a is connected to the unlocking operation handle 64. When the unlocking operation handle 64 is pressed downward, the positioning pin 64a moves forward. The rear end of the forward-moving positioning pin 64a is released from engagement with the positioning recess 7b. Therefore, when the positioning of the rotary table 4 is released by operating the handle 61, the rotary table 4 can rotate freely in the left and right directions. When the unlocking operation handle 64 is lifted upward, the positioning pin 64a moves backward. The rear end of the positioning pin 64a abuts against the outer periphery of the angled dial 7. When the rotary table 4 is rotated horizontally by holding the handle 61, the positioning pin 64a enters any of the positioning recesses 7b provided on the outer periphery of the angled dial 7. In this way, the rotary table 4 is positioned at a predetermined angle corresponding to the positioning recess 7b.

[0080] like Figure 6 As shown, a tilting and fixing mechanism 65 is provided at the front of the worktable extension 5, which holds the main support arm 50 in a position where it can tilt in the left and right directions. The tilting and fixing mechanism 65 has a tilting and fixing operation part 66 and a drive shaft 66a. The tilting and fixing operation part 66 is located between the handle part 61 and the front end of the worktable extension 5. The tilting and fixing operation part 66 can rotate about an axis coaxial with the handle part 61. The tilting and fixing operation part 66 has a concave and convex shape on its periphery that is different from the concave and convex shape of the handle part 61, so that the user can easily grip and rotate it. Therefore, the user can easily distinguish the tilting and fixing operation part 66 and the handle part 61 when gripping it, thereby preventing accidental operation.

[0081] When rotating Figure 5 , Figure 6 When the tilting and fixing operating part 66 is shown, the drive shaft 66a rotates around its axis. The drive shaft 66a extends along the length of the worktable extension 5 in the front-rear direction to the lower part of the main support arm 50. A receiving part 67 is provided at the lower part of the main support arm 50, and the receiving part 67 can move along an elongated hole 67a that extends in an arc shape with the left and right tilting support shaft 50a as the center. The receiving part 67 is fastened to the rear end screw of the drive shaft 66a. The receiving part 67 restricts the rotation of the drive shaft 66a around its axis through the side of the elongated hole 67a. Therefore, when the tilting and fixing operating part 66 is rotated in the tightening direction, an axial force is generated between the main support arm 50 and the arm support part 4b. As a result, the main support arm 50 and the arm support part 4b are pressed in the front-rear direction, and the main support arm 50 is fixed to the arm support part 4b at any left and right tilt angle. When the tilting and fixing operating part 66 is rotated in the loosening direction, the axial force of the drive shaft 66a is eliminated. Therefore, the main support arm 50 can tilt in the left and right directions with the left and right tilting support shaft 50a as the center.

[0082] Accordingly, Figure 7As shown, the benchtop cutting machine 1 has a motor shaft 23a of a motor 23, a first intermediate shaft 32, and an output shaft 37. The first intermediate shaft 32 rotates about an axis via the output of the motor shaft 23a. The output shaft 37 rotates about an axis via the output of the first intermediate shaft 32, thereby rotating the mounted tool 11. A fan 24 is mounted on the first intermediate shaft 32. The fan 24 rotates about an axis together with the first intermediate shaft 32 to generate airflow to cool the motor 23 and the first intermediate shaft 32.

[0083] Therefore, the fan 24 is mounted on the first intermediate shaft 32, rather than on the motor shaft 23a. By mounting the fan 24 on the first intermediate shaft 32, the fan 24 cools not only the motor 23 but also the first intermediate shaft 32. Furthermore, the airflow path extends along the power path including the first intermediate shaft 32. Accordingly, the cooling effect can be improved by utilizing a housing that covers the power path. In addition, one or more intermediate shafts can be provided between the motor shaft 23a and the output shaft 37.

[0084] like Figure 7 As shown, the first intermediate shaft 32 is directly connected to the motor shaft 23a, or rotates around its axis at the same speed as the motor shaft 23a. That is, the first intermediate shaft 32 is positioned near the motor 23. For example, the first intermediate shaft 32 is connected to the motor shaft 23a without the need for a reduction gear or the like. Therefore, the fan 24 provided on the first intermediate shaft 32 can also effectively cool the relatively nearby motor 23.

[0085] like Figure 7 As shown, the first intermediate shaft 32 has an upstream end 32a that receives the output from the motor shaft 23a and a downstream end 32s that transmits the output to the output shaft 37. The fan 24 is located closer to the downstream end 32s than the center of the first intermediate shaft 32 in the longitudinal direction. Therefore, the airflow from the motor 23 passes through most of the first intermediate shaft 32 and reaches the fan 24. Accordingly, the first intermediate shaft 32 can be effectively cooled.

[0086] like Figure 7 As shown, the axial length 24e of the fan 24 is longer than 1 / 4 of the diameter of the fan 24. That is, the axial length of the fan 24 is longer and the diameter is smaller. Therefore, the diameter of the intermediate shaft housing 31 that houses the fan 24 and the first intermediate shaft 32 can be reduced without reducing the airflow generated by the fan 24.

[0087] like Figure 7 As shown, the center line 32w of the first intermediate shaft 32 is located on an imaginary orthogonal plane S1 that is orthogonal to the output shaft 37, or inclined at less than 10° relative to the imaginary orthogonal plane S1. When the cutter 11 is a saw blade, the first intermediate shaft 32 is arranged approximately parallel to the disc surface of the saw blade. Therefore, the size of the cutting machine body 10 in the output shaft direction is avoided.

[0088] like Figure 7 As shown, the motor shaft 23a and the first intermediate shaft 32 are coaxially arranged. Therefore, the housing covering the motor shaft 23a and the first intermediate shaft 32 can be reduced radially. Alternatively, the airflow from the cooling fan 24 and the first intermediate shaft 32 flows in a roughly straight line. Therefore, the decrease in airflow can be suppressed.

[0089] like Figure 7 As shown, the electric motor 23 is housed in a motor housing 20 made of synthetic resin. The first intermediate shaft 32 is housed in an intermediate shaft housing 31 made of lightweight metal. Therefore, the insulation of the conductive parts surrounding the electric motor 23 can be ensured by the motor housing 20. Furthermore, the heat generated in the first intermediate shaft 32 can be transferred to the lightweight metal intermediate shaft housing 31 for cooling.

[0090] like Figure 2 As shown, when viewed from the axial direction (side view) of the output shaft 37, the fan 24 is arranged to overlap with the saw blade, which serves as the cutting tool 11. Therefore, the fan 24 can be placed within the space surrounding the relatively large saw blade. This allows for miniaturization of the cutting machine.

[0091] like Figure 7 As shown, motor 23 is an AC motor. Compared to a DC motor, an AC motor generates more heat and has a larger volume. Therefore, based on this feature, cooling efficiency can be significantly improved, and miniaturization can also be significantly achieved.

[0092] like Figure 7 As shown, the first intermediate shaft 32 is supported by two bearings 32h and 32i that are rotatable about an axis. The fan 24 is located between the two bearings 32h and 32i. Therefore, the two bearings 32h and 32i together with the first intermediate shaft 32 stably support the fan 24.

[0093] like Figure 7 As shown, a fan housing section 31g houses a fan 24. An intermediate shaft housing section 31f, with a smaller cross-sectional area than the fan housing section 31g, is provided. The intermediate shaft housing section 31f houses a portion of a first intermediate shaft 32 upstream of the fan 24. A buffer section 31e is provided, which includes a step created by the difference in cross-sectional areas between the intermediate shaft housing section 31f and the fan housing section 31g. Therefore, airflow passes through the smaller cross-sectional area intermediate shaft housing section 31f and reaches the larger cross-sectional area fan housing section 31g. Then, the airflow is dispersed near the fan 24 via the buffer section 31e. This allows for smooth airflow.

[0094] like Figure 10As shown, the fan 24 has blades 24a extending radially. The blades 24a have an inner circumferential portion 24b that protrudes in the rotational direction T on the inner circumferential side. The blades 24a also have an outer circumferential portion 24c that protrudes in the direction opposite to the rotational direction T on the outer circumferential side. With this structure, the blades 24a are able to generate a strong wind.

[0095] like Figure 10 As shown, the outer periphery 24c of the blade has an inverted inclined portion 24d extending radially outward from the bottom of the recess in the direction of rotation T. The inverted inclined portion 24d is located radially outward at a position halfway down the radius R of the fan 24. Therefore, the inverted inclined portion 24d is located only in the outer periphery of the fan 24. Accordingly, the fan 24 can effectively generate airflow.

[0096] like Figure 10 As shown, the outer periphery 24c of the blade has an inverted inclined portion 24d extending radially outward from the bottom of the recess in the direction of rotation T. The inverted inclined portion 24d is located radially outward in a region that is more than halfway along the radial length of the blade 24a. Therefore, the inverted inclined portion 24d is located only in the outer periphery of the fan 24. Accordingly, the fan 24 can effectively generate airflow.

[0097] like Figure 10 As shown, the outer peripheral end of the inverted tilted portion 24d extends at an angle of 30° to 60° relative to the imaginary radial line Y of the fan 24. This structure allows the blade 24a to effectively generate airflow.

[0098] like Figure 9 As shown, the device includes a fixed cover 12 that covers the tool 11 and a fan housing 31d that houses the fan 24. A left-side exhaust port 32p is provided on the fan housing 31d. The left-side exhaust port 32p opens towards the fixed cover 12. Therefore, air is exhausted from the fan housing 31d to the fixed cover 12. This prevents air from blowing directly onto the operator or reduces the amount of air blowing directly onto the operator.

[0099] like Figure 7 As shown, the electric work machine has a motor shaft 23a of a motor 23 and a first intermediate shaft 32. The first intermediate shaft 32 is coaxially configured with the motor shaft 23a and rotates about the axis via the output of the motor shaft 23a. A fan 24 is mounted on the first intermediate shaft 32. The fan 24 rotates together with the first intermediate shaft 32 about the axis to generate airflow to cool the motor 23 and the first intermediate shaft 32.

[0100] Therefore, the fan 24 is mounted on the first intermediate shaft 32, rather than on the motor shaft 23a. By mounting the fan 24 on the first intermediate shaft 32, the fan 24 cools not only the motor 23 but also the first intermediate shaft 32. Furthermore, by using the first intermediate shaft 32, the motor shaft 23a can be shortened, thereby reducing the size of the motor housing 20. Alternatively, the airflow path can be extended along the power path including the first intermediate shaft 32. Accordingly, the cooling effect can be improved by utilizing a housing that covers the power path.

[0101] Other embodiments of the present invention will now be described. Furthermore, in the following description, the same reference numerals are used to denote structures identical to those in the first embodiment, and their descriptions are omitted.

[0102] like Figure 11 As shown, the first intermediate shaft 70 of the second embodiment has a cross-section reduction portion 71. The cross-section reduction portion 71 is formed by a plurality of first recesses 72 extending along the outer peripheral surface of the first intermediate shaft 70. The cross-section of the first recesses 72 is arc-shaped. Each first recess 72 is formed, for example, in a manner in which four are arranged circumferentially. The first recesses 72 extend linearly along the axial direction. Each first recess 72 is formed by ball end milling. Two, three, or more first recesses 72 can be formed circumferentially. The depth of the first recesses 72 can be any depth.

[0103] like Figure 12 As shown, the first intermediate shaft 80 of the third embodiment has a cross-section reduction portion 81. The cross-section reduction portion 81 is formed by a second recess 82 extending along the outer peripheral surface of the first intermediate shaft 80. The cross-section of the second recess 82 is arc-shaped. The second recess 82 is formed in a spiral shape. The second recess 82 is formed by ball end milling.

[0104] like Figure 13 As shown, the cutting machine body 90 of the fourth embodiment includes a cutting tool 11 and a motor housing 91 disposed above the cutting tool 11. The motor housing 91 is a generally cylindrical component extending in the left-right direction. A motor 92 is housed in the motor housing 91. A motor shaft 92a is provided at the center of the motor 92. The motor shaft 92a extends in the left-right direction along a motor axis J orthogonal to the side of the cutting tool 11. The motor shaft 92a is supported by a first bearing 92b and a second bearing 92c, enabling it to rotate about the motor axis J. A first drive bevel gear 92d is integrally mounted on the right side of the motor shaft 92a. An air inlet 93 for drawing in external air is provided on the left surface of the motor housing 91.

[0105] The cutting machine body 90 has a power transmission unit 100 that transmits the driving force of the motor shaft to the output shaft 37. The power transmission unit 100 is housed in an intermediate shaft housing 101 and a gear housing 102. The intermediate shaft housing 101 is connected to an opening at the right end of the motor housing 91. The gear housing 102 connects the opening at the lower end of the intermediate shaft housing 101 and the opening at the right end of the gear housing 12a.

[0106] A first intermediate shaft 110 is housed in an intermediate shaft housing 101. The first intermediate shaft 110 extends vertically in a manner orthogonal to the motor shaft 92a. The first intermediate shaft 110 is supported rotatably about its axis by a third bearing 103 and a fourth bearing 104. A first driven bevel gear 111 is formed at the upper end of the first intermediate shaft 110. The first driven bevel gear 111 meshes with a first driving bevel gear 92d. Accordingly, the first intermediate shaft 110 rotates by receiving rotational power from the motor shaft 92a. In addition, a second driving bevel gear 112 is formed at the lower end of the first intermediate shaft 110.

[0107] The first intermediate shaft 110 has an upstream portion 32b, a downstream portion 32c, and a small-diameter portion 32d between the third bearing 103 and the fourth bearing 104. A fan 24 is integrally rotatably mounted on the downstream portion 32c. The intermediate shaft housing 101 has a fan housing 107 that houses the fan 24. An outlet 108 with an opening on the right side is formed in the fan housing 107. When the fan 24 rotates, cooling air is introduced into the intermediate shaft housing 101 from the air inlet 93 through the motor housing 91. The air flowing into the intermediate shaft housing 101 is discharged from the outlet 108 through the intermediate shaft housing portion 31f and the fan housing portion 31g. Accordingly, the motor 92 and the first intermediate shaft 110 are cooled.

[0108] A second intermediate shaft 120 and an output shaft 37 are housed in a gear housing 102 and a gear receiving portion 12a. The second intermediate shaft 120 extends in a left-right direction orthogonal to the first intermediate shaft 110. The second intermediate shaft 120 is supported rotatably about its axis by a fifth bearing 105 and a sixth bearing 106. A second driven bevel gear 121 is integrally mounted on the second intermediate shaft 120. The second driven bevel gear 121 meshes with a second driving bevel gear 112. Accordingly, the second intermediate shaft 120 rotates by receiving rotational power from the motor shaft 92a via the first intermediate shaft 110. The second intermediate shaft 120 has a reduction gear 35b that meshes with a reduction gear 37a of the output shaft 37. The output shaft 37 rotates by receiving rotation from the second intermediate shaft 120.

[0109] Various modifications can be made to the embodiments described above. For example, a tabletop cutting machine can be used as an example of a sliding circular saw. Alternatively, the invention can also be applied to a tabletop circular saw, for example. In addition, the invention can also be applied to an angle grinder, a die grinder, and a concrete vibrator as an electric work machine, for example.

[0110] The fan can also be located on the second or third intermediate shaft. The fan can also be located upstream of the first intermediate shaft.

Claims

1. A tabletop cutting machine, characterized in that, It includes a motor shaft, intermediate shaft, output shaft, and fan. The intermediate shaft rotates about the axis through the output of the motor shaft; The output shaft rotates the mounted tool by rotating about an axis through the output of the intermediate shaft; The fan is mounted on the intermediate shaft and rotates together with the intermediate shaft about the axis to generate airflow to cool the motor and the intermediate shaft.

2. The tabletop cutting machine according to claim 1, characterized in that, The intermediate shaft is directly connected to the motor shaft or rotates around the axis at the same speed as the motor shaft.

3. The tabletop cutting machine according to claim 1 or 2, characterized in that, The intermediate shaft has: an upstream end that receives the output from the motor shaft; and a downstream end that transmits the output to the output shaft. The fan is located at the downstream end side, which is closer to the center of the intermediate shaft along its length.

4. The tabletop cutting machine according to any one of claims 1 to 3, characterized in that, The axial length of the fan is longer than 1 / 4 of the diameter of the fan.

5. The tabletop cutting machine according to any one of claims 1 to 4, characterized in that, The centerline of the intermediate shaft is located on an imaginary orthogonal plane or inclined at less than 10° relative to the imaginary orthogonal plane.

6. The tabletop cutting machine according to any one of claims 1 to 5, characterized in that, The motor shaft and the intermediate shaft are coaxially configured.

7. The tabletop cutting machine according to any one of claims 1 to 6, characterized in that, It has a motor housing and an intermediate shaft housing, wherein, The motor housing is made of synthetic resin and is used to house the motor; The intermediate shaft housing is made of light metal and is used to house the intermediate shaft.

8. The tabletop cutting machine according to any one of claims 1 to 7, characterized in that, When viewed from the axial direction of the output shaft, i.e., from the side, the fan is configured to overlap with the cutting tool, i.e., the saw blade.

9. The tabletop cutting machine according to any one of claims 1 to 7, characterized in that, The motor is an AC motor.

10. The tabletop cutting machine according to any one of claims 1 to 9, characterized in that, It has two bearings that support the intermediate shaft in a manner that allows it to rotatably about an axis. The fan is located between the two bearings.

11. The tabletop cutting machine according to any one of claims 1 to 10, characterized in that, It has a fan housing, an intermediate shaft housing, and a buffer section, wherein, The fan housing is used to house the fan; The cross-sectional area of ​​the intermediate shaft housing is smaller than that of the fan housing, and the intermediate shaft housing houses a portion of the intermediate shaft on the upstream side of the fan. The buffer section includes a step formed by the difference in cross-sectional area between the intermediate shaft housing section and the fan housing section.

12. The tabletop cutting machine according to any one of claims 1 to 11, characterized in that, The fan has blades that extend radially. The blade has an inner circumferential portion that protrudes in the direction of rotation on the inner circumferential side and an outer circumferential portion that protrudes in the direction opposite to the direction of rotation on the outer circumferential side.

13. The tabletop cutting machine according to claim 12, characterized in that, The outer periphery of the blade has an inverted inclined portion that extends radially outward from the bottom of the recess in the direction of rotation. The tilted portion is located radially outward at a position half the radius of the fan.

14. The tabletop cutting machine according to claim 12 or 13, characterized in that, The outer periphery of the blade has an inverted inclined portion that extends radially outward from the bottom of the recess in the direction of rotation. The inverted tilt section is located radially outward from the midpoint of the radial length of the blade.

15. The tabletop cutting machine according to claim 13 or 14, characterized in that, The outer peripheral end of the inverted tilted portion extends at an angle of 30° to 60° relative to the radial line of the fan.

16. The tabletop cutting machine according to any one of claims 1 to 7, characterized in that, It has a mounting cover, a fan housing, and an exhaust port, wherein, The fixing cover is used to cover the cutting tool; The fan housing is used to house the fan; The outlet is located on the fan housing and opens into the mounting cover.

17. An electric work machine, characterized in that, It includes a motor shaft, an intermediate shaft, and a fan, among which, The intermediate shaft is coaxially configured with the motor shaft and rotates about the axis through the output of the motor shaft; The fan is mounted on the intermediate shaft and rotates together with the intermediate shaft about the axis to generate airflow to cool the motor and the intermediate shaft.

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