Work machine

Abstract

The objective of the present invention is to improve the workability of a working machine. A brushcutter 10 comprises a motor 32, a control unit 38, a fan 36, a housing 62, and a front cover 112. The control unit 38 is equipped with a micro-controller for controlling the drive of the motor 32. The fan 36 generates an air current K by accepting a driving force of the motor 32. The housing 62 accommodates the motor 32, the control unit 38 and the fan 36, and has an opening portion 66. The control unit 38 has a flat plate shape having a maximum external size when viewed from a front-rear direction, and is disposed between the opening portion 66 and the fan 36 in the front-rear direction. The front cover 112 is provided upright from an inner wall surface 62A of the housing 62 so as to overlap the control unit 38 when viewed from the front-rear direction.

Description

Work equipment

[0001] The present invention relates to a work machine that is operated by being driven by a motor.

[0002] In the work machine disclosed in Patent Document 1, a control board that controls the rotation of the electric motor is provided inside the motor housing, and a heat sink is attached to the control board.

[0003] Japanese Patent Application Laid-Open No. 2022-84079

[0004] In a work machine in which a controller equipped with a control unit controls the drive of a motor, as in Patent Document 1, when the workload of the work machine increases, the controller attempts to pass more current. As a result, the amount of heat generated by the control unit may increase compared to the amount of heat generated before the workload increased. In this case, the current used is controlled so as not to exceed an upper limit, which may cause the operation of the work machine to be stopped, thereby reducing the workability of the work machine.

[0005] An object of the present invention is to provide a work machine with improved workability.

[0006] In one embodiment, the work machine comprises a motor, a controller having a control unit that controls the drive of the motor, a fan that generates an airflow by receiving the drive force of the motor, and a housing that accommodates the motor, the controller, and the fan and has an opening, wherein the controller has a flat plate shape whose external dimensions are greatest when viewed from a first direction, and is positioned between the opening and the fan in the first direction, and has a wall portion that stands up from the inner wall of the housing so as to overlap with the controller when viewed from the first direction.

[0007] According to the present invention, the workability of a work machine can be improved.

[0008] 9 is a right side view of a brush cutter as an example of a work machine. FIG. 9 is a perspective view of the drive unit with the battery unit removed. FIG. 9 is a perspective view of the drive unit with the left housing removed. FIG. 9 is a cross-sectional view (cross-sectional view taken along line 4-4 in FIG. 9) showing the internal structure of the drive unit. FIG. 9 is a perspective view of the control unit as seen diagonally from the front. FIG. 9 is a rear view of the control unit as seen from the rear. FIG. 9 is a plan view of the control unit as seen from above. FIG. 9 is a left side view of the control unit as seen from the left. FIG. 9 is a left side view of the drive unit as seen from the left with the left housing removed. FIG. 9 is a perspective view of the drive unit as seen diagonally from the front with the left housing removed. FIG. 9 is a right side view of the drive unit as seen from the right with the right housing removed. FIG. 9 is a cross-sectional view (cross-sectional view taken along line 15-15 in FIG. 9) showing the arrangement of the control unit inside the housing. FIG. 9 is a cross-sectional view (cross-sectional view taken along line 16-16 in FIG. 9) showing the arrangement of the control unit inside the housing. 18 is a cross-sectional view (cross-sectional view taken along line 211-211 in FIG. 18) showing the internal structure of the hammer drill.

[0009] An embodiment of the present invention will be described below with reference to the drawings. In each drawing, the directions indicated by the front and rear arrows are the front-rear direction, the directions indicated by the left and right arrows are the left-right direction, and the directions indicated by the top and bottom arrows are the up-down direction.

[0010] 1 shows a brush cutter 10 as an example of a work machine. The brush cutter 10 is used, for example, to cut grass and small trees. The brush cutter 10 has a main pipe 12, a handle attachment 14, a gearbox 22, a rotary blade 24, a grip 26, and a drive unit 28.

[0011] The main pipe 12 is a cylindrical member extending in one direction. A drive shaft (not shown) is inserted inside the main pipe 12. A handle (not shown) for gripping by an operator can be attached to the handle attachment portion 14. A lever 27 operated by the operator is provided on the grip 26. When the amount of operation of the lever 27 by the operator is changed, a microcomputer 56 (FIG. 5), which will be described later, controls the operation to change the rotation speed of the rotary blade 24. A gear box 22 is provided at one end of the main pipe 12. The rotary blade 24 is attached to the gear box 22. The gear box 22 transmits driving force generated in a drive unit 28, which will be described later, to the rotary blade 24. The drive unit 28 is provided at the other end of the main pipe 12.

[0012] As shown in FIG. 2 , the drive unit 28 has a unit main body 30. An attachment portion 31 is provided at the rear end of the unit main body 30. A battery pack 29 is detachably provided in the attachment portion 31. The battery pack 29 is detachable by moving vertically relative to the attachment portion 31. Specifically, the battery pack 29 is attached to the attachment portion 31 by moving downward relative to the attachment portion 31, and detached from the attachment portion 31 by moving upward relative to the attachment portion 31. When attached to the attachment portion 31, the battery pack 29 supplies power to a motor 32 ( FIG. 3 ), which will be described later. In other words, the battery pack 29 functions as a power source for the drive unit 28.

[0013] 3, the unit main body 30 includes a motor 32, a fan 36, a control unit 38, a housing 62, and a front cover 112. The motor 32, the fan 36, and the control unit 38 are housed in a space 65 inside the housing 62. The space 65 will be described later.

[0014] (Motor) As shown in FIG. 4 , the motor 32 is a brushless motor. The central axis of the motor 32 is a first central axis CA, which is represented by a dashed line CA. The first central axis CA extends in the front-to-rear direction. The motor 32 has a main body case 33 and a shaft 34. The shaft 34 rotates around the first central axis CA. The shaft 34 also extends forward from the main body case 33. The driving force of the motor 32 is transmitted to the drive shaft described above via a transmission unit (not shown). In other words, the motor 32 rotates the drive shaft via the transmission unit.

[0015] (Fan) The fan 36 is provided at the front end of the shaft 34. The fan 36 is a centrifugal fan. The central axis of the fan 36 is designated CB and is represented by a dashed line CB. The second central axis CB extends in the front-rear direction. The second central axis CB and the first central axis CA are aligned in the front-rear direction. In other words, the first central axis CA and the second central axis CB are arranged on the same straight line (not shown). The fan 36 generates an airflow in the space 65 by receiving the driving force of the motor 32. The airflow generated by the rotation of the fan 36 flows from a plurality of intake ports 67 (FIG. 4) to a plurality of exhaust ports 68 (FIG. 4), which will be described later.

[0016] (Control Unit) As shown in FIG. 5 , the control unit 38 includes a case 42 and a substrate 51. The control unit 38 is an example of a controller. The control unit 38 has an octagonal outer shape (a rectangular shape with four corners cut out) when viewed from the front-to-rear direction. The control unit 38 also has a flat plate shape whose outer size is greatest when viewed from the front-to-rear direction. Thus, the front-to-rear direction is an example of a first direction and corresponds to the thickness direction of the control unit 38. The left-to-right direction is an example of a second direction. The up-to-down direction is an example of a third direction. When viewed from the front-to-rear direction, the left-to-right direction and the up-to-down direction intersect with each other.

[0017] As shown in Figures 5, 6, 7, and 8, the case 42 is formed in a dish shape that opens forward. The case 42 is made of a metal member. However, the case 42 may also be made of a resin member. The vertical length of the case 42 is longer than the horizontal length of the case 42. The case 42 houses the board 51 so that the mounting surface 52A of the board 51 is exposed forward. Specifically, the case 42 has a rear wall 43 and a peripheral wall 44 that extends upright forward from the outer edge of the rear wall 43. The rear wall 43 has a flat rear surface 43A (Figure 6) that extends in the vertical and horizontal directions. A tapered surface 47 is formed in the portion from the peripheral edge of the rear surface 43A to the rear end of the peripheral wall 44.

[0018] As shown in Figure 5, the peripheral wall 44 is formed in a frame shape with an octagonal outer shape when viewed from the front. The peripheral wall 44 also has an octagonal outer peripheral surface 45 when viewed from the front. The outer peripheral surface 45 has a flat upper surface 45A, a sloped surface 45B, a left side surface 45C, a sloped surface 45D, a lower surface 45E, a sloped surface 45F, a right side surface 45G, and a sloped surface 45H. The upper surface 45A and the lower surface 45E extend in the left-right direction. The left side surface 45C and the right side surface 45G extend in the up-down direction.

[0019] The substrate unit 51 includes, for example, a control board 52, a FET (field effect transistor) 53, a shunt resistor 54, a capacitor 55, a microcomputer 56, and a connector 57. Other mounted components are not shown or described. For example, the control board 52 has a rectangular shape with each of the four corners cut into an L-shape when viewed from the front-to-rear direction. The control board 52 is housed in the case unit 42 with the front-to-rear direction being the thickness direction. Furthermore, the control board 52 is fixed to the case unit 42 with a plurality of screws 59. The front surface of the control board 52 is referred to as a mounting surface 52A.

[0020] The FET 53, shunt resistor 54, capacitor 55, microcomputer 56, and connector 57 are mounted on mounting surface 52A so as to be visible from the front. The microcomputer 56 is mounted on a portion of the control board 52 to the right of the center in the horizontal direction. The area where the microcomputer 56 is mounted and where a circuit pattern (not shown) related to the operation of the microcomputer 56 is formed is referred to as mounting area S1. The microcomputer 56 is an example of a control unit that controls the drive of the motor 32 ( FIG. 3 ). The microcomputer 56 controls the torque and rotation speed of the motor 32 by adjusting the operating voltage and frequency using an inverter circuit including the FET 53.

[0021] The FET 53, shunt resistor 54, and capacitor 55 are mounted on the left side of the center of the control board 52 in the horizontal direction. The area where the FET 53, shunt resistor 54, and capacitor 55 are mounted and where a circuit pattern (not shown) is formed is referred to as mounting area S2. Current flows through mounting area S2 to supply the motor 32. For example, connector 57 is provided across the lower end of mounting area S1 and the lower end of mounting area S2. Mounting areas S1 and S2 are covered from the front with resin R ( FIG. 4 ). Resin R is filled inside the case 42 and cured. An example of resin R is a curable resin such as urethane. Resin R is not shown in figures other than FIGS. 4 and 17 .

[0022] The amount of current used to drive the motor 32 is greater than the amount of current used to control the drive of the motor 32. In other words, when the motor 32 is operating, the total amount of current flowing in the mounting area S2 is greater than the total amount of current flowing in the mounting area S1. Therefore, the amount of heat generated in the mounting area S2 is greater than the amount of heat generated in the mounting area S1. If the amount of heat generated in the mounting area S2 exceeds the allowable amount, the operation of each element, including the FET 53, may become unstable. In other words, if the amount of heat generated in the mounting area S2 is large, the operation of the motor 32 may become unstable. Therefore, the operation of the motor 32 is more likely to be stable if the cooling capacity of the mounting area S2 is greater than the cooling capacity of the mounting area S1.

[0023] In the brush cutter 10 (FIG. 1), the microcomputer 56 is used as an example of a control unit and an example of a first element. The FET 53 is used as an example of a second element. That is, the control unit 38 includes the microcomputer 56 and the FET 53, which generates more heat during operation than the microcomputer 56. Note that at least one of the shunt resistor 54 and the capacitor 55 may be used as an example of the second element.

[0024] 2, the housing 62 is formed in a box shape extending in the front-rear direction when viewed from the left-right direction. A power transmission unit 63 that houses a drive shaft (not shown) is provided at the front end of the housing 62. A connector (not shown) is provided in the mounting portion 31. When the battery pack 29 is mounted in the mounting portion 31, power is supplied from the battery pack 29 to the inside of the housing 62.

[0025] As shown in Figure 4, the housing 62 accommodates the motor 32, the control unit 38, and the fan 36 inside. The housing 62 also has an opening 66. When viewed from the top-bottom direction, an imaginary line passing through approximately the center of the housing 62 in the front-to-rear direction and extending in the left-to-right direction is defined as a reference line A. The housing 62 is also divided into left and right halves, as will be described later. An imaginary plane passing through the center of the housing 62 in the left-to-right direction and extending in the up-to-down direction is defined as a dividing plane D. The dividing plane D is represented by a dashed line D.

[0026] The opening 66 has a plurality of intake ports 67 and a plurality of exhaust ports 68. The plurality of intake ports 67 are located rearward of the reference line A and forward of the mounting portion 31. The plurality of intake ports 67 are also lined up at intervals in the up-down direction on the right and left sides of the dividing plane D. Furthermore, the plurality of intake ports 67 are located rearward of the control unit 38. The rear side in the front-to-rear direction is an example of one side in the first direction.

[0027] The multiple exhaust ports 68 are located forward of the reference line A and rearward of the power transmission unit 63. The multiple exhaust ports 68 are also arranged at intervals in the up-down direction on the right and left sides of the dividing plane D. The multiple exhaust ports 68 are also located forward of the control unit 38. In other words, the control unit 38 is disposed between the multiple exhaust ports 68, which are part of the opening 66, and the fan 36 in the front-to-rear direction. The front side in the front-to-rear direction is an example of the other side in the first direction.

[0028] The intake port 67 and the exhaust port 68 are, for example, formed in a rectangular shape extending in the front-to-rear direction, and connect the inside and outside of the housing 62. In other words, air, as an example of gas, can flow through the intake port 67 and the exhaust port 68. As the fan 36 rotates, air that flows into the inside of the housing 62 through the intake port 67 flows forward inside the housing 62 and is discharged to the outside through the exhaust port 68.

[0029] The housing 62 is divided into a right side and a left side of the dividing plane D. That is, the housing 62 has a right housing 71 and a left housing 81. The right housing 71 is an example of a first housing. The left housing 81 is an example of a second housing. The right side is an example of one side in the second direction. The left side is an example of the other side in the second direction.

[0030] The intake port 67 provided in the right housing 71 is referred to as intake port 67R. The exhaust port 68 provided in the right housing 71 is referred to as exhaust port 68R. The intake port 67 provided in the left housing 81 is referred to as intake port 67L. The exhaust port 68 provided in the left housing 81 is referred to as exhaust port 68L. In this way, the housing 62 is provided with a plurality of intake ports 67R, 67L and a plurality of exhaust ports 68R, 68L.

[0031] As shown in FIG. 9 , the right housing 71 has a bottom wall 72, a front wall 73, a vertical wall 74, a right side wall 75, and an upper wall 76. The bottom wall 72 is formed as a plate having a predetermined thickness in the vertical direction. The front wall 73 extends upright from the front end of the bottom wall 72. The vertical wall 74 extends upright from the rear end of the bottom wall 72. The right side wall 75 extends upright from the right end of the bottom wall 72. The upper wall 76 extends in the left-right and front-rear directions from the upper ends of the front wall 73, the vertical wall 74, and the right side wall 75. The area surrounded by the bottom wall 72, the front wall 73, the vertical wall 74, the right side wall 75, and the upper wall 76 is referred to as a right space portion 65R. The right housing 71 has a joint surface 78, which is the left end surface of the right housing 71. The inner surface of the right housing 71 is referred to as an inner wall surface 71A. The inner wall surface 71A is an example of an inner wall of the first housing.

[0032] As shown in FIG. 12 , the left housing 81 has a bottom wall 82, a front wall 83, a vertical wall 84, a left side wall 85, and an upper wall 86. The bottom wall 82 is formed as a plate having a predetermined thickness in the vertical direction. The front wall 83 extends upright from the front end of the bottom wall 82. The vertical wall 84 extends upright from the rear end of the bottom wall 82. The left side wall 85 extends upright from the left end of the bottom wall 82. The upper wall 86 extends in the left-right and front-rear directions from the upper ends of the front wall 83, the vertical wall 84, and the left side wall 85. The area surrounded by the bottom wall 82, the front wall 83, the vertical wall 84, the left side wall 85, and the upper wall 86 is referred to as a left space 65L. The left housing 81 has a joint surface 88, which is the right end surface of the left housing 81. The inner surface of the left housing 81 is referred to as an inner wall surface 81A. The inner wall surface 81A is an example of an inner wall of the second housing. The inner wall surface 71A (FIG. 9) and the inner wall surface 81A together form an inner wall surface 62A. The inner wall surface 62A is an example of an inner wall of the housing 62.

[0033] As shown in Figure 4, when the mating surfaces 78 and 88 are aligned in the left-right direction and fastened with screws (not shown), the housing 62 and the space 65 inside the housing 62 are formed. The space 65 has a right space 65R and a left space 65L. The mating surfaces 78 and 88 are included in the dividing plane D. A rear wall 79 is provided behind the vertical wall 74. A rear wall 89 is provided behind the vertical wall 84.

[0034] The space 65 includes a fan housing chamber 65A that houses the fan 36, a motor housing chamber 65B that houses the motor 32, and a controller housing chamber 65C that houses the control unit 38. The fan housing chamber 65A is located rearward of the front wall 73 ( FIG. 9 ) and the front wall 83 ( FIG. 12 ). The motor housing chamber 65B is located rearward of the fan housing chamber 65A. The controller housing chamber 65C is located rearward of the motor housing chamber 65B. Note that in the left housing 81, no wall is provided between the motor housing chamber 65B and the controller housing chamber 65C. In other words, in the left housing 81, a flow passage 77 through which gas can flow is formed between the motor housing chamber 65B and the controller housing chamber 65C. Meanwhile, in the right housing 71, a front cover 112 (described later) is provided between the motor housing chamber 65B and the controller housing chamber 65C in the front-rear direction.

[0035] A flow path section 92 is provided between the control unit 38 and the vertical walls 74, 84 in the front-rear direction. The flow path section 92 includes the vertical walls 74, 84, and multiple flow path forming plates 94. Each flow path forming plate 94 has a predetermined thickness in the up-down direction. The multiple flow path forming plates 94 are arranged at intervals in the up-down direction. The flow path forming plate 94 is formed by aligning a right plate portion 94A located on the right side of the dividing plane D and a left plate portion 94B located on the left side of the dividing plane D in the left-right direction. The right plate portion 94A extends forward from the vertical wall 74 and extends to the periphery of the intake port 67R. The left plate portion 94B extends forward from the vertical wall 84 and extends to the periphery of the intake port 67L. In this way, gas can flow through the flow path section 92, and gas drawn in through the multiple intake ports 67R, 67L flows to the control unit 38.

[0036] A notch 96 and a unit support portion 98 ( FIG. 11 ) are formed at the front end of the flow path forming plate 94. The notch 96 is cut out from the center in the left-right direction at the front end of the flow path forming plate 94 so as to recess toward the rear. When viewed from the top-bottom direction, the notch 96 is V-shaped. In other words, the closer the notch 96 is to the center in the left-right direction, the farther it is from the control unit 38. The multiple notches 96 are aligned in the top-bottom direction, allowing airflow in the top-bottom direction. In this way, the notch 96 is an example of a through-hole, which penetrates the flow path portion 92 in the top-bottom direction and allows ventilation. In this embodiment, the notch 96 is included in the category of a through-hole.

[0037] 11 and 14 , the unit support portions 98 are formed on the right and left sides of the cutout portion 96 at the front end portion of the flow path forming plate 94. The unit support portion 98 has a support surface 98A that faces the rear surface 43A and the tapered surface 47 ( FIG. 6 ). The support surface 98A is formed to match the shapes of the rear surface 43A and the tapered surface 47. The support surface 98A comes into contact with at least one of the rear surface 43A and the tapered surface 47, causing the unit support portion 98 to support the control unit 38 from behind.

[0038] Partition walls 102 are provided at positions forward of the unit support parts 98 and outboard of the control unit 38 (FIG. 4) in the left-right direction. The partition walls 102 protrude from the inner wall surface 62A toward the center in the left-right direction and are formed in the shape of a plate with its thickness extending in the front-to-rear direction. The partition walls 102 extend in the up-down direction.

[0039] 15, the vertical height of the partition wall 102 is approximately the same as the vertical height of the control unit 38. The upper and lower ends of the partition wall 102 can come into contact with the left side surface 45C and the right side surface 45G of the control unit 38. In this manner, the control unit 38 can be supported by the unit support portion 98 (FIG. 11) and the partition wall 102. In other words, the housing 62 can support both left and right ends of the control unit 38.

[0040] A portion of the partition wall 102 that is aligned with the control unit 38 in the left-right direction and that is recessed away from the control unit 38, excluding the upper and lower ends of the partition wall 102, is recessed. In other words, a slit-like gap 104 is formed between a portion of the partition wall 102 and the control unit 38. When viewed from the front-to-rear direction, the gap 104 is formed in a rectangular shape extending in the up-down direction. The gap 104 is large enough to allow gas to flow in the front-to-rear direction. Furthermore, the gap 104 is located on both the left-to-right outer sides of the control unit 38. The amount of gas flowing through the gap 104 is smaller than the amount of gas flowing through the ventilation paths 106 and 107, which will be described later. In other words, most of the gas flows through the ventilation paths 106 and 107, and the remaining gas flows through the gap 104.

[0041] As shown in Figures 10 and 15, the right housing 71 is provided with ventilation paths 106 and 107. When the control unit 38 is attached to the housing 62, the ventilation paths 106 and 107 are located on both vertically outer sides of the control unit 38. The ventilation path 106 is located above the area corresponding to the mounting area S1 (Figure 5) of the control unit 38, allowing gas to circulate in the front-to-rear direction. The ventilation path 107 is located below the area corresponding to the mounting area S1 of the control unit 38, allowing gas to circulate in the front-to-rear direction. The ventilation paths 106 and 107 are not provided in the left housing 81.

[0042] 13 and 15, the left housing 81 is provided with limiting walls 108, 109. When the control unit 38 is attached to the housing 62, the limiting walls 108, 109 are located on both vertically outer sides of the control unit 38. The limiting walls 108, 109 each have a plate-like portion that extends in the left-right and up-down directions. When viewed from the left-right direction, the limiting walls 108, 109 are each bent in a crank shape.

[0043] The limiting wall 108 is located above the area corresponding to the mounting area S2 (FIG. 5) of the control unit 38, and restricts the flow of gas in the front-to-rear direction. The lower end of the limiting wall 108 contacts the upper end of the peripheral wall 44 from the front. The limiting wall 109 is located below the area corresponding to the mounting area S2 of the control unit 38, and restricts the flow of gas in the front-to-rear direction. The upper end of the limiting wall 109 contacts the lower end of the peripheral wall 44 from the front. The limiting walls 108 and 109 are not provided on the right housing 71 (FIG. 9).

[0044] The limiting wall 108 is aligned with the air passage 106 in the left-right direction and is located on the left side of the air passage 106. The limiting wall 109 is aligned with the air passage 107 in the left-right direction and is located on the left side of the air passage 107. As such, when viewed from the front-to-rear direction, the limiting walls 108 and 109 that limit the airflow on the left side of the air passages 106 and 107 are provided inside the housing 62. The lower end of the limiting wall 108 and the upper end of the limiting wall 109 function as restricting portions that restrict the control unit 38 from tilting forward.

[0045] As shown in FIG. 16 , the front cover 112 extends from the inner wall surface 71A of the right housing 71 toward the right side (toward the left housing 81) in the left-right direction. The front cover 112 is an example of a wall portion. When viewed from the front to the rear in the front-to-rear direction, the front cover 112 extends so as to overlap the right side of the dividing plane D of the control unit 38. In other words, when viewed from the front to the rear, the front cover 112 is located on the right side, which is the other side in the left-to-right direction. A left end surface 113 is formed at the left end of the front cover 112. The left end surface 113 is an example of a tip of a wall portion. The left end surface 113 is formed flat and located on the dividing plane D. In this way, the front cover 112 is provided only on the inside of the right housing 71, and is not provided on the inside of the left housing 81 ( FIG. 12 ).

[0046] As shown in FIG. 9 , the front cover 112 has a bottom wall 112A, an inclined wall 112B, a front wall 112C, an inclined wall 112D, and an upper wall 112E. The bottom wall 112A is located below the control unit 38 and extends forward of the control unit 38. The inclined wall 112B extends obliquely upward from the front end of the bottom wall 112A. The front wall 112C extends upward in the vertical direction from the upper end of the inclined wall 112B. The inclined wall 112D extends obliquely rearward from the upper end of the front wall 112C. The upper wall 112E extends rearward from the upper end of the inclined wall 112D. The upper wall 112E is located above the control unit 38.

[0047] 16 , when viewed from front to rear in the front-to-rear direction, the front cover 112 overlaps with the fan 36. Specifically, when the fan 36 is projected onto the front cover 112 in the front-to-rear direction, a portion of the fan 36 to the right of the dividing plane D overlaps with the front cover 112. When viewed in the front-to-rear direction, a portion of the fan 36 to the left of the dividing plane D does not overlap with the front cover 112, but overlaps with the control unit 38.

[0048] When viewed in the front-to-rear direction, the FET 53, the shunt resistor 54, and part of the capacitor 55 are located between the left end surface 113 and the inner wall surface 81A. In other words, when viewed in the front-to-rear direction, the FET 53, the shunt resistor 54, and part of the capacitor 55 are not covered by the front cover 112. Therefore, after cooling the FET 53, the shunt resistor 54, and the capacitor 55, the airflow is not restricted by the front cover 112 and can flow forward through the circulating portion 77.

[0049] As shown in FIG. 9 , the controller housing chamber 65C is provided with sloped surfaces 114A and 114B. The sloped surface 114A extends diagonally downward from the lower end of the vertical wall 74 toward the bottom wall 112A. The sloped surface 114B extends diagonally upward from the upper end of the vertical wall 74 toward the upper wall 112E. This allows gas that flows into the controller housing chamber 65C from the multiple air intakes 67R to be guided by the sloped surfaces 114A and 114B and flow into the air passages 106 and 107. The controller housing chamber 65C is octagonal when viewed left to right.

[0050] 12 , the controller housing chamber 65C is provided with inclined surfaces 116A and 116B. The inclined surface 116A extends diagonally downward from the lower end of the vertical wall 84 toward a position below the control unit 38. The inclined surface 116B extends diagonally upward from the upper end of the vertical wall 84 toward a position above the control unit 38. Note that the left housing 81 is provided with restricting walls 108 and 109. Therefore, the forward flow of gas that flows into the controller housing chamber 65C from the multiple air intake ports 67L is restricted by the inclined surfaces 116A and 116B.

[0051] 17 , when the motor 32 of the brush cutter 10 starts operating, the fan 36 rotates, generating an airflow in the space 65 of the housing 62. Specifically, gas (e.g., air) that flows into the space 65 through the air intakes 67 flows forward through the space 65 and is then exhausted outside the housing 62 through the air exhausts 68. Specifically, the gas that flows in through the air intakes 67R and the gas that flows in through the air intakes 67L flow behind the control unit 38, thereby cooling the rear of the control unit 38. In the following description, the gas flow is indicated by arrow K and referred to as airflow K.

[0052] As shown in FIG. 15 , the airflow K1 refers to the airflow that flows behind the control unit 38 and through the space facing the upper part of the control unit 38. The airflow K2 refers to the airflow that flows behind the control unit 38 and through the space facing the lower part of the control unit 38. The airflow K1 flows toward the open air passage 106 because its forward flow is restricted by the control unit 38 and the restricting wall 108. After passing forward past the control unit 38 by passing through the air passage 106, the airflow K1 begins to flow downward and forward. The airflow K2 flows toward the open air passage 107 because its forward flow is restricted by the control unit 38 and the restricting wall 109. After passing forward past the control unit 38 by passing through the air passage 107, the airflow K2 begins to flow upward and forward. A portion of the airflow K1 and a portion of the airflow K2 merge to become the airflow K.

[0053] 17 , the airflow K that has passed the control unit 38 attempts to flow further forward. Here, the airflow K collides with the front cover 112, which restricts its forward movement, and is guided by the front cover 112 so that it flows toward the left side of the control unit 38. In other words, the airflow K has its direction of travel turned back at the front cover 112, so that it flows toward the front of the left side of the control unit 38.

[0054] 15 and 17 , the airflow K flows in front of the left side portion of the control unit 38 and collides with the circuit board 51, causing the airflow K to turn back toward the front. Here, the airflow K flows through the FET 53, the shunt resistor 54, and the capacitor 55. This cools the FET 53, the shunt resistor 54, and the capacitor 55. After flowing forward, the airflow K passes through the multiple exhaust ports 68 and is exhausted outside the housing 62.

[0055] Note that gaps 104 are provided on both left and right outer sides of the control unit 38. Therefore, part of the airflow K flowing through the flow path 92 flows forward through the gaps 104, thereby cooling the left side surface 45C and the right side surface 45G, and therefore both left and right ends of the case 42 can also be cooled.

[0056] A detailed description will be given below with reference to FIGS. 1 to 17 . Individual reference numbers will be omitted. In the brush cutter 10, rotation of the fan 36 generates airflow K toward the control unit 38. The rear portion of the control unit 38 is cooled by the airflow K. After cooling the rear portion of the control unit 38, the airflow K flows along the control unit 38 and passes over the control unit 38 from the rear to the front in the front-to-rear direction. When viewed from the front-to-rear direction, the front cover 112 is positioned so as to overlap the control unit 38. Therefore, the airflow K that passes over the control unit 38 to the front impinges on the front cover 112. The airflow K that impinges on the front cover 112 is redirected and flows toward the control unit 38. In particular, the airflow K is guided by the front cover 112 and flows toward the mounting area S2. The airflow K then cools the FET 53, the shunt resistor 54, and the capacitor 55. In this way, cooling not only the rear but also the front of the control unit 38 suppresses temperature rises in the microcomputer 56, and in particular in the FET 53, shunt resistor 54, and capacitor 55. Therefore, even if the load acting on the brush cutter 10 increases during operation, the operation of the circuit including the microcomputer 56, FET 53, shunt resistor 54, and capacitor 55 is stable, allowing the motor 32 to continue operating. In other words, stopping of the brush cutter 10 due to a temperature rise in the control unit 38 is suppressed, improving the operability of the brush cutter 10.

[0057] According to the brush cutter 10, the ventilation passages 106, 107 that allow ventilation to the control unit 38 and the upper and lower ends of the partition wall 102 that supports the control unit 38 are arranged separately in the left-right and up-down directions. This makes it possible to increase the flow area of ​​the ventilation passages 106, 107 and to make it easier to prevent the control unit 38 from tilting, compared to a brush cutter in which the ventilation portion and the portion that supports the control unit 38 are located in the same area.

[0058] In the brush cutter 10, the restricting walls 108, 109 restrict the airflow K on the left side of the air passages 106, 107. This causes the airflow K to flow to the right side of the air passages 106, 107. The airflow K that passes over the control unit 38 then collides with the front cover 112 and is guided toward the left side of the control unit 38 (mounting area S2). In other words, compared to a configuration in which the air passages 106, 107 are fully open in the left-right direction, the airflow K that flows through the air passages 106, 107 is more likely to flow toward the front cover 112 and be turned back, making it easier to cool the front portion of the control unit 38.

[0059] In the brush cutter 10, the airflow K generated by the rotation of the fan 36 flows from the multiple air intakes 67, past the control unit 38, and to the multiple air exhausts 68. Because the multiple air intakes 67 are provided on both left and right sides of the housing 62, air intake is easier than in a configuration in which the air intakes 67 are provided on only one left or right side. Furthermore, because the flow path 92 guides the airflow K toward the control unit 38, more of the airflow K can flow toward the rear surface 43A of the control unit 38.

[0060] According to the brush cutter 10, part of the airflow K guided by the flow passages 92 flows vertically through the cutouts 96. After reaching the upper and lower ends of the control unit 38, the vertically flowing airflow K passes over the control unit 38 in the front-to-rear direction. This makes it difficult for part of the airflow K to remain in each flow passage 92, making it easier for the airflow K to pass over the control unit 38 in the front-to-rear direction.

[0061] According to the brush cutter 10, the space required for providing the fan 36 and the front cover 112 can be made smaller in the left-right or up-down direction compared to a configuration in which the fan 36 and the front cover 112 do not overlap when viewed from the front-to-back direction, thereby making it possible to make the brush cutter 10 smaller.

[0062] With the brush cutter 10, the space required for installing the motor 32 and fan 36 can be reduced in the left-right or up-down direction compared to a configuration in which the first central axis CA and the second central axis CB are not aligned in the front-to-back direction, thereby making it possible to make the brush cutter 10 smaller.

[0063] According to the brush cutter 10, the front cover 112 is provided only on the right housing 71. This allows the front cover 112 and the right housing 71 to be molded as a single unit. This reduces the number of steps required to manufacture the brush cutter 10 compared to a configuration in which the front cover 112 and the right housing 71 are separate units.

[0064] In the brush cutter 10, the airflow K is guided by the front cover 112 and flows toward the left end surface 113 of the front cover 112 and toward the mounting area S2 of the control unit 38. When viewed from the front to the rear in the front-to-rear direction, the FET 53 is located between the left end surface 113 and the inner wall surface 81A. In other words, the FET 53 is located on the path of the airflow K. This makes it easier for the airflow K to cool the FET 53, which generates a large amount of heat.

[0065] [Modifications of the Present Embodiment] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. In the above description, the motor 32 rotates the rotary blade 24 as a tool, but the motor 32 is not limited to driving a tool. The fan 36 is not limited to a centrifugal fan, and may be an axial fan. If the fan 36 is an axial fan, the fan 36 may be disposed rearward of the control unit 38 and blow air toward the rear surface 43A of the control unit 38. The brush cutter 10 may have components arranged in a reversed left-right orientation relative to the dividing plane D.

[0066] The components may be arranged with the up-down direction being an example of the second direction and the left-right direction being an example of the third direction. The case portion 42 is not limited to being a collection of flat surfaces, but may also have a partially curved surface. The housing 62 is not limited to being divided into two parts, but may also have a partially curved surface. The front cover 112 is not limited to being a collection of flat surfaces, but may also have a partially curved surface. Instead of the cutout portion 96, the flow path forming plate 94 may have a through hole that passes through the flow path forming plate 94 in the up-down direction. The number of the through hole may be either single or multiple.

[0067] The front cover 112 may extend beyond the dividing plane D to the left side. In this configuration, the limiting walls 108, 109 may be omitted. The flow path portion 92 may not be provided in the housing 62. For example, multiple flow path forming plates 94 may not be provided. When there is only one flow path forming plate 94, the cutout portion 96 may not be provided. When viewed from the front-to-rear direction, the fan 36 and the front cover 112 may not overlap.

[0068] The first central axis CA and the second central axis CB do not have to be aligned in the front-rear direction. When viewed from the top-bottom direction, the front cover 112 may be erected from the inner wall surface 71A toward the control unit 38 in a direction intersecting the left-right direction. Furthermore, the front cover 112 is not limited to being flat, and may be entirely curved, or may have a curved surface formed in part. A portion of each of the FET 53, the shunt resistor 54, and the capacitor 55 may be arranged to overlap the front cover 112 when projected in the front-rear direction.

[0069] 18 and 19 show a hammer drill 200 according to a second embodiment of the present invention. The hammer drill 200 includes a motor 202, including a rotor 202A, a stator 202B, and a drive shaft 202C, housed within a housing 201. A mechanism 204, which receives driving force from the motor 202 and operates a tool bit 210, performs drilling or crushing work on a target material such as concrete. The mechanism 204 uses the driving force of the motor 202 to apply to the tool bit both a striking force that strikes the tool bit in the longitudinal direction (front-rear direction) of the tool bit and a rotational force that rotates the tool bit about an axis extending in the longitudinal direction (front-rear direction). The housing 201 is provided with a switching operation unit (not shown) that switches the mode of the mechanism unit 204; when the mode of the mechanism unit 204 is set to hammer mode using the switching operation unit, only an impact force is applied to the tip tool; when the mode of the mechanism unit 204 is set to hammer drill mode, an impact force and a rotational force are applied to the tip tool; and when the mode of the mechanism unit 204 is set to drill mode, only a rotational force is applied to the tip tool.

[0070] A control unit 205 that controls the drive of the motor 202 is housed inside the housing 201. The control unit 205 includes a control board 205A, an FET 205B (an example of a switching element) mounted on the control board 205A, and a case 205C that houses the control board 205A. The case 205C is made of metal and covers the rear surface and the top, bottom, left, and right surfaces of the control board 205A, and is box-shaped with an open front. The control unit 205 has a flat plate shape with its outer diameter at its largest when viewed from the front (first direction).

[0071] An air intake 201B is provided in the housing 201. A fan 203 is attached to a drive shaft 202C of the motor 202. The fan 203 is located forward of the control unit 205, and the air intake 201B is located rearward of the control unit 205; therefore, the control unit 205 is disposed between the air intake 201B and the fan 203 in the front-to-rear direction. A limiting wall 206 separates the space rearward from the space in front of the control unit 205 into front and rear spaces, with the air intake 201B connected to the rear space. The limiting wall 206 overlaps with the control unit 205 in the front-to-rear direction. The limiting wall 206 is also provided with an air passage 207 disposed adjacent to the control unit 205 in the left-to-right direction. The air passage 207 may be disposed on at least one of the left and right sides of the control unit 205; however, in this embodiment, the air passage 207 is disposed on both the left and right sides. On the front side of the limiting wall 206, the space facing the control unit 205 and the space in which the motor 202 is provided are divided into front and rear spaces by a front cover 208 that stands upright from the inner wall of the housing 201. The front cover 208 is arranged so as to overlap the control unit 205 when viewed in the front-to-rear direction as shown in Fig. 19 , and is positioned so that its position in the front-to-rear direction is between the control unit 205 and the fan 203. The front cover 208 is provided with a circulating portion 209 that is arranged below the ventilation path 207 and that connects the space facing the control unit 205 and the space in which the motor 202 is provided.

[0072] The airflow K generated by the fan 203 when the motor 202 is driven and flows around the control unit 205 will now be described. The airflow K enters the housing 201 through the intake port 201B and flows upward along the rear surface of the case portion 205C, moving away from the center of the control unit 205 in the left-right direction. As it does so, the airflow K cools the case portion 205C and indirectly cools the control board 205A and FET 205B. The airflow K then passes through the air passage 207 in the limiting wall 206, entering the space behind the limiting wall 206 and into the space in front of it. At this time, the airflow K changes course toward the center of the control unit 205 in the left-right direction. The airflow K then collides with the front cover 208, changing course downward and rearward. In other words, the front cover 208 directs the airflow K downward toward the flow section 209. At this time, the airflow K collides with the control board 205A, particularly with the periphery of the FET 205B, cooling them. The airflow K then passes through the circulating portion 209 and flows forward of the front cover 208, passes around the periphery of the motor 202, and flows upward toward the fan 203, before flowing out of the housing 201 through the exhaust port 201C.

[0073] In the hammer drill 200 of the second embodiment, the control unit 205, particularly the FET 205B, is cooled effectively, thereby improving the workability of the work machine.

[0074] The working machine to which the present invention is applicable is not limited to brush cutters and hammer drills, but can be applied to various working machines having a motor, a controller, and a fan.

[0075] 10...brush cutter (an example of a working machine), 32...motor, 36...fan, 38...control unit (an example of a controller), 53...FET (an example of a second element), 56...microcomputer (an example of a control unit and an example of a first element), 62...housing, 62A...inner wall surface (an example of an inner wall of a housing), 66...opening, 67...intake port, 68...exhaust port, 71...right housing (an example of a first housing), 71A...inner wall surface (an example of an inner wall of a first housing), 81...left housing (an example of a second housing), 81A...inner wall surface (an example of an inner wall of a second housing), 92...flow path portion, 96...notch portion (an example of a through hole), 1 06...ventilation passage, 107...ventilation passage, 108...restricting wall, 109...restricting wall, 112...front cover (an example of a wall portion), 113...left end surface (an example of a tip), CA...first central axis, CB...second central axis, 201...housing, 201A...handle, 201B...intake port, 201C...exhaust port, 202...motor, 202A...rotor, 202B...stator, 202C...drive shaft, 203...fan, 204...mechanism, 205...control unit, 205A...control board, 205B...FET, 205C...case portion, 206...restricting wall, 207...ventilation passage, 208...front cover, 209...circulation portion, 210...tipped tool

Claims

1. A motor; A controller including a control unit for controlling the driving of the motor; a fan that generates an airflow by receiving a driving force of the motor; a housing that houses the motor, the controller, and the fan and has an opening; the controller has a flat plate shape whose outer size is greatest when viewed from a first direction, and is disposed between the opening and the fan in the first direction; an air passage that serves as a passage through which air flows from one side to the other side in the first direction with respect to the controller; a limiting wall disposed on one side of the air passage in a second direction perpendicular to the first direction and limiting the airflow; a wall portion erected from an inner wall of the housing on the other side in the second direction so as to overlap with the controller when viewed from the first direction.

2. A motor, A controller including a control unit for controlling the driving of the motor; a fan that generates an airflow by receiving a driving force of the motor; a housing that houses the motor, the controller, and the fan and has an opening; the controller has a flat plate shape whose outer size is greatest when viewed from a first direction, and is disposed between the opening and the fan in the first direction; When viewed from the first direction, directions intersecting each other are a second direction and a third direction, When viewed from the first direction, the opening is provided adjacent to the controller in the second direction, the housing is provided to be capable of supporting both end portions of the controller in the second direction, an air passage is provided on the housing outside the controller in the third direction; A work machine, wherein a restricting wall that restricts airflow on one side of the air passage in the second direction is provided inside the housing when viewed from the first direction.

3. A motor, A controller including a control unit for controlling the driving of the motor; a fan that generates an airflow by receiving a driving force of the motor; a housing that houses the motor, the controller, and the fan and has an opening; the controller has a flat plate shape whose outer size is greatest when viewed from a first direction, and is disposed between the opening and the fan in the first direction; When viewed from the first direction, directions intersecting each other are a second direction and a third direction, an air passage is provided on both outer sides of the controller in the third direction in the housing; When viewed from the first direction, a limiting wall that limits an air flow on one side of the air passage in the second direction is provided inside the housing, A work machine having a wall portion erected from an inner wall of the housing on the other side in the second direction so as to overlap with the controller when viewed from the first direction.

4. the opening has a plurality of intake ports located on one side of the controller in the first direction and a plurality of exhaust ports located on the other side, The work machine according to claim 3 , wherein the housing is provided with the plurality of intake ports on both sides in the second direction, and is provided with a flow path through which gas flows from the plurality of intake ports to the controller.

5. The work machine according to claim 4 , wherein the flow path portion is provided with a through hole that penetrates the flow path portion in the third direction and allows ventilation.

6. The work machine according to claim 1 or 3, wherein the fan and the wall portion overlap when viewed from the first direction.

7. The work machine according to claim 6 , wherein a first central axis of the motor and a second central axis of the fan are aligned in the first direction.

8. the housing includes a first housing and a second housing divided into one side and the other side in the second direction intersecting the first direction, The work machine according to claim 7 , wherein the wall portion stands from an inner wall of the first housing toward the second housing.

9. The controller includes a first element and a second element that generates more heat during operation than the first element, The work machine according to claim 8 , wherein the second element is located between a tip end of the wall portion and an inner wall of the second housing when viewed from the first direction.

10. A motor; A controller including a control unit for controlling the driving of the motor; a fan that generates an airflow by receiving a driving force of the motor; a housing that houses the motor, the controller, and the fan and has an air intake; the controller has a flat plate shape whose outer size is greatest when viewed from a first direction, and is disposed between the air intake and the fan in the first direction; the housing defines an air passage that is disposed at a position overlapping with the controller in the first direction, and a circulating portion that is disposed between the controller and the fan in the first direction and does not overlap with the air passage when viewed in the first direction, a wall portion erected from an inner wall of the housing so as to direct the air flow that has passed through the air passage toward the circulation portion.