Electric work equipment and angle tools

Abstract

This prevents malfunctions caused by foreign objects being sucked into the cooling channel, and also prevents a decrease in cooling performance. [Solution] The grinder 1 includes a motor housing 3 that houses the motor 6, a rear cover 4 positioned on the axis L of the motor shaft 14 of the motor 6 and housing electrical components other than the motor 6 (switch 8, controller 9, brush 36, power cord 10), and a fan 16 that rotates in conjunction with the drive of the motor 6. Cooling passages are formed inside the motor housing 3 and the rear cover 4 through which air drawn in by the rotation of the fan 16 passes. Inside the rear cover 4, an intake air passage 62 is formed as part of the cooling passage, which includes an outer rear intake port 57 that draws in air from the radially outside of the motor shaft 14, and an outlet 63 that is close to the motor 16 in the axis L direction and exhausts air toward the motor 16.

Description

Technical Field

[0001] The present disclosure relates to an electric working machine such as a grinder, and an angle tool in which an output shaft is orthogonal to a motor shaft.

Background Art

[0002] A grinder, which is an example of an electric working machine, grinds or polishes a workpiece by rotating a tip tool mounted on a front output shaft through driving of a motor built in a housing extending in the front-rear direction. For example, Patent Document 1 discloses a grinder in which a rear cover that houses a controller and a switch is provided at a rear portion of a motor housing that houses a motor, allowing an operator to grip the rear cover. In this grinder, a fan is provided on a rotating shaft of the motor, air intake ports are formed on a side surface and a rear surface of the rear cover, an exhaust port is formed in a gear housing that houses the output shaft, and a cooling flow path is formed inside. That is, when the fan rotates together with the rotating shaft, an air flow is generated in the cooling flow path, in which air sucked from the rear air intake port passes through the controller and the motor and is discharged from the exhaust port, so that the controller and the motor can be cooled.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In the above-mentioned conventional grinder, dust sucked together with outside air from the air intake port during operation adheres to electrical components such as the switch and the controller, which may cause a failure due to a short circuit or the like. There has also been a concern that if the side air intake port is blocked by an operator's hand gripping the rear cover, the amount of sucked air will decrease, lowering the cooling performance of the controller and the motor.

[0005] Therefore, the purpose of this disclosure is to provide an electric work machine that can prevent malfunctions caused by foreign matter being sucked into the cooling channel, as well as prevent a decrease in cooling performance. [Means for solving the problem]

[0006] To achieve the above objective, the first configuration of this disclosure comprises a first housing for housing a motor, A second housing is positioned on the axis of the motor shaft of the motor and houses electrical components other than the motor, Includes a fan that rotates in conjunction with the drive of the motor, This is an electric work machine in which cooling channels are formed in the first housing and the second housing through which air drawn in by the rotation of the fan passes. Furthermore, the second housing is characterized in that an intake air passage is formed as part of the cooling flow path, including an inlet that draws in air from the radially outside of the motor shaft and an outlet that approaches the motor in the axial direction and exhausts air toward the motor. To achieve the above objective, the second configuration of this disclosure comprises a front housing having an output shaft mounted at the lower end of which a cutting tool is attached in the vertical direction, A first housing is positioned behind the front housing and extends in the front-rear direction, housing a motor whose motor shaft axis is in the front-rear direction, A second housing is positioned at the rear of the first housing and extends in the front-rear direction, housing electrical components other than the motor, Includes a fan that rotates in conjunction with the drive of the motor, This angle tool has cooling channels formed within the first housing and the second housing through which air drawn in by the rotation of the fan passes. Furthermore, within the second housing, an intake air passage is formed as part of the cooling channel, the inlet opening toward the radially outward direction of the motor shaft and the outlet opening toward the forward direction in the axial direction and close to the motor. [Effects of the Invention]

[0007] According to this disclosure, since the outlet of the intake air passage is close to the motor, foreign matter drawn in with outside air from the inlet of the intake air passage during operation is less likely to adhere to electrical components, reducing the risk of malfunctions caused by short circuits, etc. In addition, since the air passing through the intake air passage is exhausted towards the motor, the motor is cooled efficiently. Therefore, it is possible to prevent malfunctions caused by foreign matter drawn into the cooling passage, and also to prevent a decrease in cooling performance. [Brief explanation of the drawing]

[0008] [Figure 1] This is a rear perspective view of the grinder in Example 1. [Figure 2] This is a central longitudinal cross-sectional view of the grinder of Example 1. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] This is a perspective view of the inner housing section with the rear cover removed in Example 1. [Figure 5] This is a rear view of the grinder in Example 1. [Figure 6] This is a front perspective view of the rear cover of Example 1. [Figure 7] This is a perspective view of the central vertical section of the rear cover of Example 1. [Figure 8] Figure 2 is a cross-sectional view along line BB. [Figure 9] Figure 2 is an enlarged cross-sectional view along the CC line. [Figure 10] Figure 3 is an enlarged diagram illustrating the airflow in the rear cover area. [Figure 11] This is a rear perspective view of the grinder in Example 2. [Figure 12] This is a rear view of the grinder in Example 2. [Figure 13] Front view of the rear cover of Example 2 [Figure 14] Figure 12 is an explanatory diagram showing the airflow in the rear cover section of the DD line cross-section, with the viewer's view enlarged. [Figure 15]It is an enlarged sectional view taken along line E-E in Fig. 14. MODE FOR CARRYING OUT THE INVENTION

[0009] In one embodiment of the present disclosure, the outlet may be located axially between the motor and a central portion of the electrical component. According to this aspect, the airflow can be brought into contact with the motor from a position close to the motor. In one embodiment of the present disclosure, the intake air passage may be formed in an axially extending tubular shape by a peripheral wall portion of the second housing and an inner wall portion provided inside the peripheral wall portion. According to this aspect, air can flow smoothly toward the motor side, enabling efficient cooling. In one embodiment of the present disclosure, at least a portion of the inlet may be provided in the peripheral wall portion. According to this aspect, a wide opening area can be secured in the peripheral wall portion to intake a necessary amount of air, and efficient cooling can be achieved. In one embodiment of the present disclosure, the inlet provided in the peripheral wall portion may face the inner wall portion. According to this aspect, even if foreign matter enters through the inlet, it can be blocked by the inner wall portion.

[0010] In one embodiment of the present disclosure, the inner wall portion may include a flat portion parallel to the axial direction. According to this aspect, air sucked in through the inlet can flow smoothly toward the motor side along the flat portion. In one embodiment of the present disclosure, the flat portion may be parallel to a virtual plane that includes the axial line and intersects the electrical component. According to this aspect, the inner wall portion can be provided by utilizing the dead space outside the electrical component, and an increase in size of the second housing can be prevented. In one embodiment of the present disclosure, the cross-sectional shape orthogonal to the axial line in the intake air passage may be a flat plate shape parallel to the flat portion. According to this aspect, the intake air passage can be provided by utilizing the dead space outside the electrical component, and an increase in size of the second housing can be prevented.

[0011] In one embodiment of the present disclosure, a second inlet communicating with an intake air passage may be provided at the end of the second housing on the side opposite to the motor. This configuration allows the air in the intake duct to flow in a straight line, leading to improved cooling efficiency. In one embodiment of the present disclosure, the second entrance may be an oval shape extending parallel to the planar portion. This configuration allows for the provision of a second inlet connected to the intake air passage in a space-saving manner. In one embodiment of the present disclosure, there is an output shaft that is inclined at a predetermined angle with respect to the motor shaft, and the output shaft may be arranged on a virtual plane. This configuration allows the output axis to be placed in the dead space on the virtual plane, preventing the device from becoming larger in the direction perpendicular to the virtual plane. In one embodiment of this disclosure, the entrance provided in the peripheral wall may penetrate in a direction perpendicular to a virtual plane that includes the axis and intersects with the electrical component. With this configuration, even if the hand gripping the surrounding wall touches the inlet, a decrease in the amount of air drawn in is less likely to occur. In one embodiment of the present disclosure, the motor is a brushed motor, and the brushes may be located in a position other than the extension of the intake air passage. This configuration allows the brushes to be placed in dead space that does not interfere with the cooling channel, preventing the unit from becoming too large and suppressing a decrease in cooling efficiency. In one embodiment of this disclosure, the electrical component may be a controller for controlling a brushed motor. This configuration effectively prevents foreign matter from adhering to the controller. [Examples]

[0012] The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is a perspective view of a grinder, which is an example of an electric power tool and angle tool. Figure 2 is a central longitudinal cross-section of the grinder. Figure 3 is a cross-sectional view taken along line AA of Figure 2. The grinder 1 has a housing that forms its outer casing, consisting of a gear housing 2, a motor housing 3, and a rear cover 4, from front to back. The gear housing 2 is made of metal, while the motor housing 3 and rear cover 4 are made of resin. The gear housing 2 includes a spindle 5 that protrudes downward. The spindle 5 is an example of an output shaft in this disclosure. The motor housing 3 is cylindrical in shape, extending in the front-to-back direction, and houses the motor 6. A switch knob 7 is provided on the left side of the motor housing 3 so as to be slidable back and forth. The motor housing 3 is an example of the first housing of this disclosure. The rear cover 4 is cylindrical, extending in the front-to-back direction, similar to the motor housing 3, and houses the switch 8 and controller 9. A power cord 10 is connected to the rear of the rear cover 4. The rear cover 4 is an example of the second housing of this disclosure.

[0013] Motor 6 is a commutator motor having a stator 11, a rotor 12, and a commutator 13, and is driven by AC power supplied from an external source. The motor shaft 14, which is attached to the rotor 12, extends in the front-rear direction and has its front end protruding into the gear housing 2. A bevel gear 15 is provided at the front end of the motor shaft 14. A fan 16 is provided on the motor shaft 14 at the front of the motor housing 3. The fan 16 is a centrifugal fan, and a baffle plate 17 that expands as it extends forward is provided on the rear outer circumference.

[0014] A gear housing cover 20 is provided between the gear housing 2 and the motor housing 3, through which the motor shaft 14 passes. The gear housing cover 20 is provided with a bearing 21 that supports the motor shaft 14. A bevel gear 22 is provided on the upper part of the spindle 5 within the gear housing 2. The bevel gear 22 meshes with the bevel gear 15 of the motor shaft 14. Multiple exhaust ports 23, 23... are formed on the front surface of the gear housing 2. A bearing box 24 is assembled to the lower part of the gear housing 2. The spindle 5 is supported by an upper bearing 25 held in the gear housing 2 and a lower bearing 26 held in the bearing box 24. A cutting tool 27 can be attached to the lower end of the spindle 5 that protrudes from the bearing box 24. In Figures 1 and 2, the cutting tool 27 is exemplified as a disc-shaped grinding wheel. A tool cover 28 is fitted to the bearing box 24, covering the rear half of the cutting tool 27.

[0015] As shown in Figure 4, an inner housing portion 30 is integrally formed at the rear end of the motor housing 3. The inner housing portion 30 extends rearward within the rear cover 4. The inner housing portion 30 includes a front bearing holding portion 31 and a rear switch holding portion 32. The bearing holder 31 is cylindrical and coaxial with the axis L of the motor shaft 14, and holds the bearing 33 and supports the rear end of the motor shaft 14. A magnet 34 for detecting rotational speed is attached to the rear end of the motor shaft 14, which extends rearward from the bearing 33. Brush holders 35, 35 are provided above and below the bearing holder 31 on the front side of the bearing 33. The brush holders 35, 35 hold the brushes 36, 36 that contact the commutator 13. The brushes 36 are an example of electrical components other than the motor of this disclosure. The switch holding portion 32 extends rearward from the bearing holding portion 31. The switch holding portion 32 has an upper holding plate 37, a lower holding plate 38, and a rear holding plate 39. The upper retaining plate 37 and the lower retaining plate 38 are rectangular in shape when viewed from above, and extend backward with a vertical gap between them, in a position parallel to the plane defined in the front-rear, left-right, and right directions. The rear retaining plate 39 connects the rear ends of the upper retaining plate 37 and the lower retaining plate 38 vertically.

[0016] The switch 8 is held between the upper retaining plate 37 and the lower retaining plate 38. The switch 8 is a push switch that turns ON when the protruding button portion 8a is pressed. The switch 8 is supported in a position with the button portion 8a facing backward. The switch 8 is an example of an electrical component other than the motor of this disclosure. A slide bar 40 is provided on the left side of the inner housing portion 30 within the motor housing 3 and rear cover 4. The front end of the slide bar 40 is connected to the switch knob 7. The rear end of the slide bar 40 is bent to the right behind the switch 8, forming a pressing portion 41 that faces the button portion 8a from the rear. The slide bar 40 is biased to a retracted position where the pressing portion 41 is close to the button portion 8a by a coil spring 43 positioned between the slide bar 40 and a support portion 42 provided in the inner housing portion 30. Therefore, when the switch knob 7, which is in the retracted position together with the slide bar 40, is slid forward, the slide bar 40 moves forward, the pressing portion 41 presses the button portion 8a, and the switch 8 is turned ON.

[0017] A controller 9 is held on the lower surface of the lower retaining plate 38. The controller 9 comprises a rectangular case 45 with an opening at the bottom, and a control circuit board 46 housed inside the case 45. The control circuit board 46 consists of a CPU and memory connected to the CPU, and is electrically connected to the motor 6 and switch 8 to control the motor 6. The controller 9 has functions such as constant rotation control, soft start, and restart prevention. An adjustment dial 47 is provided at the rear of the control circuit board 46. As shown in Figure 5, the rear of the adjustment dial 47 is exposed on the rear surface of the rear wall portion 51 of the rear cover 4, which will be described later. The rotation speed of the motor 6 can be adjusted by rotating the adjustment dial 47. The rear retaining plate 39 is equipped with a cord receiving portion 48 and a screw boss 49. The power cord 10 is connected to the cord receiving portion 48. The power cord 10 extends rearward through the rear wall portion 51 of the rear cover 4. The screw boss 49 extends rearward below the cord receiving portion 48.

[0018] As shown in Figures 6 and 7, the rear cover 4 is a bottomed cylindrical shape with an open front, having a cylindrical peripheral wall portion 50 and a rear wall portion 51 that closes the rear end of the peripheral wall portion 50. The peripheral wall portion 50 is shaped to cover the inner housing portion 30 from the rear. The rear cover 4 is assembled to the inner housing portion 30 by placing its front end 4a over the rear end 3a of the motor housing 3 and screwing a screw 52 that passes through the rear wall portion 51 from the rear into a screw boss 49. In the assembled state, the bearing holding portion 31 that holds the brushes 36, 36 and the switch holding portion 32 that holds the switch 8 and controller 9 are housed inside the rear cover 4. Multiple side air intakes 53, 53... are provided on the left and right sides of the peripheral wall portion 50. In the center of the rear wall portion 51 in the left-right direction, from top to bottom, there is a cord through hole 54 through which the power cord 10 passes, a screw through hole 55 through which a screw 52 passes, and an operation window 56 that exposes the adjustment dial 47. Multiple outer rear air intakes 57, 57... and multiple inner rear air intakes 58, 58 are provided on both the left and right sides of the rear wall portion 51.

[0019] The side air intake ports 53 are slit-shaped openings extending in the front-rear direction at the rear of the peripheral wall portion 50, and are formed to penetrate in the left-right direction. As shown in Figure 8, multiple side air intake ports 53 are formed at equal intervals in the circumferential direction of the peripheral wall portion 50 (five on the left side and four on the right side). Hereafter, when distinguishing between left and right, the left side air intake port will be denoted as 53L and the right side air intake port as 53R. Similarly, when distinguishing between left and right for other components, the symbols L and R will be used. The side air intake ports 53 are an example of the inlet of the intake air passage in this disclosure. As shown in Figure 3, the right-side air intake port 53R is longer in the front-to-back direction than the left-side air intake port 53L. The right-side air intake port 53R is located further forward than the left-side air intake port 53L. The outer rear air intake ports 57 are located near the left and right outer edges of the rear wall portion 51, and as shown in Figure 5, two are provided symmetrically on each side around a virtual plane VP that includes axis L and is defined in the front-rear and up-down directions. The outer rear air intake ports 57 are oval-shaped and extend in the vertical direction, with the two on the left and right being formed in a straight line in the vertical direction. The outer rear air intake ports 57 are an example of a second inlet of the intake air passage of this disclosure. The inner rear air intake ports 58 are located inside the left and right outer rear air intake ports 57, 57, with one port on each side arranged symmetrically around the virtual plane VP. The inner rear air intake ports 58 are oval-shaped and extend horizontally, positioned slightly higher than the top surface of the controller 9 case 45.

[0020] Inner wall portions 60, 60 are formed on the left and right inner surfaces of the rear cover 4. As shown in Figures 7 to 9, the inner wall portions 60 are plate-shaped and integrally formed with the rear cover 4 inside the areas where the side air intakes 53, 53·· are formed and the outer rear air intakes 57, 57 are formed. The inner wall portions 60 include a planar portion 61 parallel to the virtual plane VP and are partially bent so as not to interfere with the switch holding portion 32. The virtual plane VP is perpendicular to the switch 8 and the controller 9. The spindle 5 is also located on the virtual plane VP. The upper ends of the inner wall portions 60, 60 are connected to the inner surface of the peripheral wall portion 50 at a position above the uppermost side air intake ports 53, 53. The lower ends of the inner wall portions 60, 60 are connected to the inner surface of the peripheral wall portion 50 at a position below the lowermost side air intake ports 53, 53. Therefore, the formation regions of the left and right side air intake ports 53, 53 face the inner wall portions 60, 60. The rear ends of the inner wall portions 60, 60 are connected to the inner surface of the rear wall portion 51 at a position inside the outer rear air intake ports 57, 57. The front ends of the inner wall portions 60, 60 protrude slightly forward of the front ends of the side air intake ports 53, 53. However, corresponding to the side air intake ports 53L, 53R of different lengths, the right inner wall portion 60R extends further forward than the left inner wall portion 60L.

[0021] Therefore, within the peripheral wall portion 50, intake air passages 62, 62 are formed that communicate with the side intake ports 53, 53 on the left and right sides, and communicate with the outer rear intake ports 57, 57 on the rear side, separating them from the housing area of ​​the switch holding portion 32. The intake air passages 62, 62 are tubular in shape extending in the front-rear direction, and their cross-sectional shape perpendicular to the axis L of the motor shaft 14 is a flat plate parallel to the planar portion 61 of the inner wall portion 60. In addition to the intake air passages 62, 62, corresponding to the inner wall portions 60L, 60R of different lengths, as shown in Figure 10, the intake air passage 62R on the right is formed to extend further forward than the intake air passage 62L on the left. Between the front ends of the left and right inner wall portions 60L and 60R and the left and right inner surfaces of the peripheral wall portion 50, outlets 63, 63 are formed that extend vertically and open forward. Both outlets 63, 63 are located in front of the switch 8 and close to the motor shaft 14. Both outlets 63, 63 are located between the motor 6 and the central part of the controller 9 in the direction of axis L. That is, as can be seen in Figure 2, the front end position F of the controller 9, the rear end position R, and the central position M in the front-rear direction including the center Z are clearly shown in Figure 3, and both outlets 63, 63 are located in the region between the motor 6 and the central position M (central part) of the controller 9 in the direction of axis L. However, due to the difference in length between the inner wall sections 60L and 60R, the right-side outlet 63R is located closer to the radially outer end of the motor shaft 14 than the left-side outlet 63L.

[0022] In this way, a cooling channel CP (Figure 10) is formed inside the grinder 1, in which air drawn in from the side intake ports 53, 53 and the rear intake ports 57, 58 as the fan 16 rotates passes through the motor 6 and then flows to the exhaust port 23. However, the air drawn in from the side intake ports 53, 53 and the outer rear intake ports 57, 57 flows forward through the intake air passages 62, 62 partitioned within the rear cover 4 and exits through the outlets 63, 63. Therefore, the air passing through the intake air passages 62, 62 hardly comes into contact with the switch 8 and the controller 9.

[0023] In the grinder 1 configured as described above, when the switch knob 7 is slid forward to turn on the switch 8, the controller 9 drives the motor 6 to rotate the motor shaft 14. As a result, the spindle 5 rotates via the bevel gears 15 and 22, and the tip tool 27 rotates, enabling grinding work and other operations. As the motor shaft 14 rotates, the fan 16 rotates, drawing air from the radially outer side of the motor shaft 14 into the side intake ports 53 when viewed from the axis L direction, and drawing air from the rear into the rear intake ports 57 and 58, creating an airflow that flows through the cooling channel CP as described above. Of this airflow, the air drawn in from the outer rear intake ports 57 flows forward from the outlets 63 and 63, respectively, through the left and right intake air passages 62, 62 as shown by the dotted arrows in Figure 10, passes through the motor 6, and is then discharged from the exhaust port 23. Thus, the motor 6 is cooled. The air drawn in from the inner rear intake ports 58 passes through the controller 9 case 45 and the motor 6 in sequence, and is then discharged from the exhaust port 23. In this way, the motor 6 and the controller 9 are cooled by the airflow that flows through the cooling channel CP.

[0024] At this time, even if foreign matter such as dust is drawn in along with the air from each side intake port 53 and each outer rear intake port 57, the foreign matter will flow forward without coming into contact with the switch 8 and controller 9 by passing through the intake air passages 62, 62 which are partitioned inside. Each inner rear intake port 58 is formed inside the left and right inner wall portions 60, 60, but the overall opening area is significantly smaller than that of the side intake ports 53 and outer rear intake ports 57, so even if foreign matter is drawn in, it will be only a small amount. Therefore, the risk of foreign matter drawn into the rear cover 4 adhering to the switch 8 or controller 9 and causing a malfunction due to a short circuit or the like is reduced. Furthermore, even if the hands of an operator gripping the peripheral wall portion 50 of the rear cover 4 block the side air intake ports 58, 58, the wide openings of the left and right side air intake ports 58, 58 are not completely blocked, and the outer rear air intake port 57 is not blocked, thus allowing the intake of outside air necessary for cooling. When the forward slide of the switch knob 7 is released, the slide bar 40 retracts due to the biasing force of the coil spring 43, releasing the pressure on the button portion 8a by the pressing portion 41. As a result, the switch 8 turns OFF and the motor 6 stops running.

[0025] As described above, the grinder 1 of Embodiment 1 includes a motor housing 3 that houses the motor 6, a rear cover 4 positioned on the axis L of the motor shaft 14 of the motor 6 and housing electrical components other than the motor 6 (switch 8, controller 9, brush 36, power cord 10), and a fan 16 that rotates in conjunction with the driving of the motor 6. Cooling passages CP are formed inside the motor housing 3 and the rear cover 4 through which air drawn in by the rotation of the fan 16 passes. Furthermore, within the rear cover 4, an intake air passage 62 is formed as part of the cooling passage CP, which includes an outer rear intake port 57 that draws in air from the radially outer side of the motor shaft 14 when viewed from the axial direction L, and an outlet 63 that is close to the motor 6 in the axial direction L and exhausts air toward the motor 6.

[0026] With this configuration, since the outlet 63 of the intake air passage 62 is close to the motor 6, foreign matter sucked in with outside air from the side intake port 53 and the outer rear intake port 57 during operation is less likely to adhere to electrical components such as the switch 8 and controller 9, reducing the risk of malfunctions caused by short circuits, etc. In addition, since the air passing through the intake air passage 62 is exhausted toward the motor 6, the motor 6 is cooled efficiently. Therefore, it is possible to prevent malfunctions caused by foreign matter sucked into the cooling passage CP, and also to prevent a decrease in cooling performance.

[0027] The outlet 63 is located between the motor 6 and the central position M of the controller 9 in the direction of the axis L. Therefore, the airflow can be directed from a position close to the motor 6 and brought into contact with the motor 6. The intake air passage 62 is formed in a tubular shape extending in the axial direction L by the peripheral wall portion 50 of the rear cover 4 and the inner wall portion 60 provided inside the peripheral wall portion 50. Therefore, air can be directed smoothly forward, enabling efficient cooling. The side air intake port 53 is provided in the peripheral wall portion 50. Therefore, a wide opening area can be secured in the peripheral wall portion 50, allowing for the intake of necessary air and enabling efficient cooling. The side air intake port 53 provided in the peripheral wall portion 50 faces the inner wall portion 60. Therefore, even if foreign matter enters through the side air intake 53, it can be blocked by the inner wall 60.

[0028] The inner wall portion 60 includes a planar portion 61 parallel to the axis L direction. Therefore, the air drawn in from the side intake port 53 can be smoothly directed forward along the flat surface 61. The planar portion 61 is parallel to a virtual plane VP that includes axis L and intersects with the switch 8 and controller 9. Therefore, the inner wall portion 60 can be provided by utilizing the dead space on the left and right outer sides of the switch 8 and controller 9, thereby preventing the rear cover 4 from becoming larger. The cross-sectional shape perpendicular to the axis L in the intake air passage 62 is a flat plate shape parallel to the planar section 61. Therefore, the intake air passage 62 can be provided by utilizing the dead space on the left and right outer sides of the switch 8 and controller 9, thereby preventing the rear cover 4 from becoming larger. An outer rear air intake port 57, which communicates with the intake air passage 62, is provided on the rear wall portion 51 of the rear cover 4, which is on the side opposite the motor. Therefore, the air in the intake air passage 62 can be directed in a straight line, leading to improved cooling efficiency. The outer rear air intake port 57 is an oval shape that extends parallel to the flat portion 61. Therefore, the outer rear air intake port 57 connected to the intake air passage 62 can be provided in a space-saving manner.

[0029] The motor has a spindle 5 that is perpendicular to the motor shaft 14, and the spindle 5 is positioned on a virtual plane VP. Therefore, the spindle 5 can be placed in the dead space on the virtual plane VP, preventing it from becoming larger in the left-right direction. The side air intake port 53 provided in the peripheral wall portion 50 penetrates in a direction perpendicular to the virtual plane VP. Therefore, even if the hand gripping the peripheral wall portion 50 touches the side air intake port 53, a decrease in the amount of air drawn in is less likely to occur. Motor 6 is a brushed motor, and the brushes 36 are positioned other than on the extension of the intake air passage 62. Therefore, the brush 36 can be placed in a dead space that does not interfere with the cooling channel CP, preventing the brush from becoming larger and suppressing a decrease in cooling efficiency. The electrical component is a controller 9 that controls a brushed motor. Therefore, the adhesion of foreign matter to the controller 9 can be effectively prevented.

[0030] Next, we will describe a modified version of Example 1. The number of side air intakes, which serve as entry points, can be increased or decreased as appropriate, not limited to the example above. The number can be the same on both the left and right sides. The shape of the side air intakes may also be the same length on both the left and right sides. The side air intakes may also be shorter in length from front to back than in the example above and arranged in a straight line in the front-to-back direction. The side air intakes are not limited to oval shapes; they may also be elliptical or circular. Side air intakes of different shapes and sizes may be mixed and arranged. The number and shape of the outer rear air intakes, which serve as the second entry point, can also be changed as appropriate, not limited to the example above. For example, the outer rear air intakes can be a single oval or multiple circular shapes. The second entrance can be omitted. The shape of the inner wall is not limited to the above example. The inner wall may be a flat plate (planar section only) that extends vertically without bending, as long as it does not interfere with the electrical components on the central side. [Examples]

[0031] Next, other embodiments of the present disclosure will be described. However, the same reference numerals will be used for the same components as in Embodiment 1, and redundant descriptions will be omitted. In the above embodiment 1, a side air intake is provided on the side surface of the peripheral wall portion 50. However, in the rear cover 4 of the grinder 1A shown in Figures 11 to 13, the portion covering the outer area of ​​the inner wall portions 60, 60 of the peripheral wall portion 50 is omitted. In other words, the inner wall portions 60, 60 are used in conjunction with the peripheral wall portion and are exposed on both the left and right sides. As shown in Figure 14, the rear end of the peripheral wall portion 50 on the front side of the inner wall portions 60, 60 forms overlapping portions 70, 70 that overlap the front ends of the inner wall portions 60, 60 from the left and right outer sides. Therefore, between the rear end of the overlapping section 70,70 and the inner wall section 60,60, side intake ports 71,71 open behind the outlet 63,63, forming intake air passages 62,62 that are shorter in the front-to-back direction than those in Example 1. However, due to the difference in length between the left and right side wall sections 60L,60R, similar to Example 1, the right side intake port 71R is located further forward than the left side intake port 71L. As shown in Figure 15, the side intake ports 71,71 are plate-shaped and extend vertically, having the same shape as the outlets 63,63. Only inner rear intake ports 58,58 are formed in the rear wall section 51, and no outer rear intake ports are formed.

[0032] In this grinder 1A, when the fan 16 rotates in conjunction with the rotation of the motor shaft 14, as shown by the dotted arrow in Figure 14, a portion of the air flowing through the cooling channel CP is drawn in from the radially outer side of the motor shaft 14 when viewed from the axis L direction into the side intake ports 71, 71, and flows forward through the left and right intake air passages 62, 62 respectively, exiting the outlets 63, 63, passing through the motor 6, and then becoming an airflow that is discharged from the exhaust port 23. Thus, the motor 6 is cooled. The air drawn in from the inner rear intake port 58 passes through the controller 9 case 45 and the motor 6 in sequence, and then becomes an airflow that is discharged from the exhaust port 23. In this way, the motor 6 and the controller 9 are cooled by the airflow passing through the interior.

[0033] In this case, even if foreign matter is sucked in along with air from the side intake ports 71, 71, it will pass through the intake air passages 62, 62 which are partitioned internally, and will flow forward without coming into contact with the switch 8 and controller 9. The risk of foreign matter being sucked in from the inner rear intake port 58 is minimal, as in Example 1. Therefore, the risk of foreign matter sucked into the rear cover 4 adhering to the switch 8 or controller 9 and causing malfunctions due to short circuits, etc., is reduced. In particular, in Embodiment 2, since the side air intakes 71, 71 are not formed on the outer circumference of the peripheral wall portion 50, the hands of the worker gripping the peripheral wall portion 50 do not block the side air intakes 71, 71, and the intake of outside air necessary for cooling is possible.

[0034] Thus, in the grinder 1A of the above embodiment 2, an intake air passage 62 is formed inside the rear cover 4, which includes a side intake port 71 that draws in air from the radially outside of the motor shaft 14, and an outlet 63 that approaches the motor 6 in the axial direction L and exhausts air toward the motor 6. With this configuration, since the outlet 63 of the intake air passage 62 is close to the motor 6, foreign matter sucked in with outside air from the side intake port 71 during operation is less likely to adhere to electrical components such as the switch 8 and controller 9, reducing the risk of malfunction due to short circuits, etc. Furthermore, since the air passing through the intake air passage 62 is exhausted toward the motor 6, the motor 6 is cooled efficiently. In particular, since the side intake port 71, which opens in the center of the peripheral wall portion 50, is not blocked by the hands of the worker gripping the rear cover 4, the reduction in the amount of air sucked in is suppressed. Therefore, it is possible to prevent malfunctions caused by foreign matter sucked into the cooling passage CP, and also to prevent a decrease in cooling performance.

[0035] Next, we will describe a modified example of Example 2. In the above example, the left and right lengths of the inner wall section may be made the same, and the positions of the side air intakes may also be made the same on both sides. The shape of the side air intakes (air intake passages) can also be appropriately changed in accordance with the changes in the shape of the inner wall section. In the above example, a side air intake is formed by providing an overlapping portion at the rear end of the peripheral wall that overlaps with the front end of the inner wall. However, the overlapping portion may be eliminated, and the rear end of the peripheral wall and the front end of the inner wall may be at the same position in the front-to-back direction. Alternatively, the inner wall may be shortened so that the front end of the inner wall is positioned further back than the rear end of the peripheral wall. In this case, the side air intake will open facing backward and inclined outwards to the left and right.

[0036] The following describes some common modifications to both Examples 1 and 2. The intake air passages may be provided above or below the motor shaft axis, rather than to the left or right. The intake air passages may be a single unit, a pair, or three or more units. The outlet of the intake air passage may be located in front of the electrical components, rather than in the center of the electrical components. The arrangement of the switches and controller is not limited to the example above. Alternatively, the controller may be placed on top and the switches on the bottom. The controller and switches may also be arranged vertically side-by-side. The shape of the inner housing can also be modified as appropriate. The grinder may be a DC tool powered by a battery pack, rather than an AC tool that uses commercial power. The motor does not have to be a brushed motor; it can be a brushless motor. The electric work implement is not limited to grinders. It may also be other grinding and polishing tools such as polishers and sanders, or other power tools such as biscuit joiners (joint cutters). It is not limited to portable work implements, but may also be stationary work implements that are placed on the floor for operation. In other words, this disclosure is applicable to any electric work implement that has a cooling channel in which air flows as the fan rotates within the housing. Therefore, the first housing and the second housing are not limited to being arranged in the front-to-back direction with respect to the end tool, but may also be arranged in the left-to-right or up-and-down direction. [Explanation of Symbols]

[0037] 1,1A...Grinder, 2...Gear housing, 3...Motor housing, 4...Rear cover, 5...Spindle, 6...Motor, 8...Switch, 9...Controller, 14...Motor shaft, 16...Fan, 23...Exhaust port, 27...Cutting tool, 30...Inner housing section, 31...Bearing holder section, 32...Switch holder section, 46...Control circuit board, 50...Peripheral wall section, 51...Rear wall section, 52...Screw, 53,71...Side intake port, 57...Outer rear intake port, 58...Inner rear intake port, 60...Inner wall section, 61...Flat section, 62...Intake air passage, 63...Outlet, 70...Overlap section, L...Axis of motor shaft, VP...Virtual plane, CP...Cooling passage.

Claims

1. A first housing that houses the motor, A second housing is positioned on the axis of the motor shaft of the motor and houses electrical components other than the motor, Includes a fan that rotates in conjunction with the drive of the motor, An electric work machine having a cooling channel formed in the first housing and the second housing through which air drawn in by the rotation of the fan passes, An electric work machine having an intake air passage formed within the second housing, which includes an inlet that draws in air from the radially outside of the motor shaft and an outlet that approaches the motor in the axial direction and exhausts air toward the motor, as part of the cooling passage.

2. The electric work machine according to claim 1, wherein the outlet is located between the motor and the central part of the electrical component in the axial direction.

3. The electric work machine according to claim 1 or 2, wherein the intake air passage is formed in a tubular shape extending in the axial direction by the peripheral wall portion of the second housing and the inner wall portion provided inside the peripheral wall portion.

4. The electric work machine according to claim 3, wherein at least a portion of the entrance is provided in the peripheral wall.

5. The electric work machine according to claim 4, wherein the entrance provided in the peripheral wall portion faces the inner wall portion.

6. The electric work machine according to any one of claims 3 to 5, wherein the inner wall portion includes a planar portion parallel to the axial direction.

7. The electric work machine according to claim 6, wherein the planar portion is parallel to a virtual plane that includes the axis and intersects with the electrical component.

8. The electric work machine according to claim 7, wherein the cross-sectional shape perpendicular to the axis in the intake air passage is a flat plate shape parallel to the planar portion.

9. An electric work machine according to any one of claims 6 to 8, wherein a second inlet communicating with the intake air passage is provided at the end of the second housing on the side opposite to the motor.

10. The electric work machine according to claim 9, wherein the second entrance is an oval shape extending parallel to the planar portion.

11. The electric work machine according to claim 7 or 8, having an output shaft that is inclined at a predetermined angle with respect to the motor shaft, wherein the output shaft is arranged on the virtual plane.

12. The electric work machine according to any one of claims 7 to 11, wherein the entrance provided in the peripheral wall penetrates in a direction perpendicular to a virtual plane that includes the axis and intersects with the electrical material component.

13. The electric work machine according to any one of claims 1 to 12, wherein the motor is a brushed motor, and the brushes are arranged at a position other than the extension of the intake air passage.

14. The electric work machine according to claim 13, wherein the electrical component is a controller for controlling the brushed motor.

15. A front housing having an output shaft in the vertical direction to which the tip tool is attached at the lower end, A first housing is located behind the front housing and extends in the front-rear direction, housing a motor whose motor shaft axis is in the front-rear direction, A second housing is positioned at the rear of the first housing, extending in the front-to-back direction, and housing electrical components other than the motor, Includes a fan that rotates in conjunction with the drive of the motor, An angle tool having a cooling channel formed in the first housing and the second housing through which air drawn in by the rotation of the fan passes, An angle tool having an intake air passage formed within the second housing as part of the cooling channel, the inlet opening radially outward from the motor shaft and the outlet opening forward in the axial direction and close to the motor.

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