Work machine

Abstract

To provide a work machine having excellent cooling performance.SOLUTION: A work machine comprises a first wall part 41 and a second wall part 42 in a motor storage part 11. The first wall part 41 overlaps with at least a portion of a region where a shift knob 21 is projected on a rear side thereof. The first wall part 41 is positioned between the shift knob 21 and a fan 35 in a longitudinal direction. The second wall part 42 overlaps with at least a portion of a region where a movable range R in a longitudinal direction of a rear end part of the shift knob 21 is projected on a lower side thereof. The second wall part 42 extends forward from a lower portion of the first wall part 41. The second wall part 42 constitutes a first partitioning part that suppresses air currents from flowing through a gap between the shift knob 21 and a housing 10 and partitions at least a portion between the shift knob 21 and an outer periphery part of a motor 30.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a work machine such as a driver drill. [Background technology]

[0002] The following Patent Document 1 discloses a driver drill in which the gear ratio can be changed by operating a shift knob. In a work machine such as a driver drill, negative pressure is generally generated in the housing by rotating a fan, and outside air is taken in through an intake port to cool the control board and motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-89717 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventor has found a problem in that the airflow passing through the gap between the shift knob and the housing is not effectively utilized for cooling, resulting in low cooling function.

[0005] An object of the present invention is to provide a work machine with good cooling properties. [Means for solving the problem]

[0006] One aspect of the present invention is a work machine. a motor having a stator and a rotor; A fan driven by the motor to generate an airflow; a housing that houses the motor and the fan, the housing having an air passage therein through which the airflow passes; An instruction unit that instructs the motor to be driven or stopped; an operation unit separate from the instruction unit, the operation unit being movably supported on the housing so as to be operable from outside; In a work machine having The housing has a first partition configured to separate the operating unit from the air passage, the first partition preventing the airflow from entering the housing through a gap between the operating unit and the housing and flowing into the air passage, and / or a second partition preventing the airflow from passing between a lower portion of the stator and an inner surface of the housing.

[0007] The present invention may be expressed as an "electric operating machine", "electric tool", "electrical equipment", etc., and such expressions are also valid as aspects of the present invention. Effect of the Invention

[0008] According to the present invention, a work machine with good cooling properties can be provided. [Brief description of the drawings]

[0009] [Figure 1] 1 is a left side view of a working machine 1 according to a first embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] Cross section AA of Figure 1. [Figure 4] FIG. 2 is a perspective view of the working machine 1 as viewed from below. [Diagram 5] FIG. 4 is a left sectional view of a work machine according to a comparative example. [Figure 6] FIG. [Figure 7] FIG. 6 is a left sectional view of a main portion of a working machine according to a second embodiment of the present invention. [Figure 8] FIG. 11 is a left sectional view of a main portion of a work machine according to a third embodiment of the present invention. [Figure 9] FIG. 11 is a left sectional view of a main portion of a work machine according to a fourth embodiment of the present invention. [Figure 10] FIG. 11 is a perspective view of a left portion of a housing in a working machine according to a fourth embodiment. [Figure 11] FIG. 11 is a perspective view of the main parts of a working machine according to a fourth embodiment, in which the right part of the housing, a tail cover 15, and the internal configuration of a motor accommodating portion 11 are omitted. [Figure 12] FIG. 13 is a perspective view of an upper portion of a housing in the third or fourth embodiment, viewed from the rear side. [Figure 13] FIG. 11 is a plan view of a work machine according to a fifth embodiment of the present invention. [Figure 14] FIG. 14 is a plan view of the shift knob 21 of FIG. 13. [Figure 15] FIG. 13 is a left sectional view of a main portion of a work machine according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Embodiment 1) 1 to 4 and 6 relate to a work machine 1 according to a first embodiment of the present invention. Fig. 5 relates to a work machine of a comparative example. The work machine of the comparative example has the same configuration as the work machine 1 except that it does not have the second wall portion 42 shown in Fig. 6. For this reason, Fig. 5 may be referred to in the description of the work machine 1.

[0011] The work machine 1 is a driver drill. 1 and 2 define mutually orthogonal front-rear, up-down, and left-right directions of the work machine 1. The front-rear direction is a direction parallel to the axial direction of the motor shaft 31.

[0012] The work machine 1 includes a housing 10. The housing 10 is, for example, a resin molded body having a two-part structure divided into left and right parts. The housing 10 has a motor housing section 11 as a first housing section, a handle section 12, and a battery pack mounting section 13 as a second housing section.

[0013] The motor housing 11 is a cylindrical part whose central axis is parallel to the front-rear direction. The work machine 1 is provided with a tail cover 15 that covers a rear opening of the motor housing 11. The work machine 1 is provided with vents 16 that serve as exhaust ports on both the left and right sides of the tail cover 15. That is, the vents 16 that serve as exhaust ports are provided in the motor housing 11.

[0014] The work machine 1 is provided with a shift knob 21 as an operation unit on the upper part of the motor housing part 11. The shift knob 21 is a gear change operation unit (gear change switch) that switches the reduction ratio of the reduction mechanism 50 shown in FIG. 5 etc., and is supported on the upper part of the motor housing part 11 so as to be movable in the front-rear direction so as to be operable from the outside. At least a part of the shift knob 21 is located radially outside the motor 30, and its presence range in the front-rear direction overlaps with the motor 30. The motor housing part 11 has dustproof ribs 47 that cover the upper parts of the front and rear parts of the shift knob 21.

[0015] The handle portion 12 extends downward from the lower portion of the motor housing portion 11. The work machine 1 is provided with a trigger switch 17 at the upper end portion of the handle portion 12 as an instruction portion for instructing to drive or stop the motor 30. The work machine 1 is provided with a forward / reverse changeover switch 19 at the boundary between the motor housing portion 11 and the handle portion 12, which can switch between forward and reverse rotation of the motor 30.

[0016] The battery pack attachment section 13 is connected to a lower end of the handle section 12. A battery pack (not shown), which serves as a power source for the work machine 1, is detachably attached to the battery pack attachment section 13.

[0017] As shown in Fig. 4, the work machine 1 has an air window 14 serving as an air intake in the battery pack mounting section 13. That is, the air window 14 is provided at a position below the handle section 12. The total area of ​​the air window 14 is larger than the total area of ​​the air intakes other than the air window 14, that is, the air intakes other than the air intake provided in the battery pack mounting section 13.

[0018] 5, the work machine 1 includes a first control board 23 and a board case 24 in the battery pack mounting section 13. The first control board 23 is equipped with a microcontroller that controls the drive of the motor 30, a switching element (inverter circuit) for supplying current to the motor 30, and the like. The board case 24 houses the first control board 23.

[0019] As shown in FIG. 5, the work machine 1 includes a motor 30, a fan 35, and a second control board 37 in the motor housing 11.

[0020] The motor 30 is, for example, an inner rotor type brushless motor, and is driven by power from a battery pack mounted in the battery pack mounting portion 13. As shown in FIG.

[0021] The fan 35 is provided behind the stator 38 and the rotor 39, and is a centrifugal fan configured to draw in air from the front side. The fan 35 rotates integrally with the motor shaft 31, and generates cooling air for cooling the motor 30, the first control board 23, the board case 24, etc. The flow of the cooling air is indicated by arrows in Figures 3, 5, and 6. The housing 10 is configured to have an air passage therein through which the air flows.

[0022] The second control board 37 is provided in front of the stator 38 and the rotor 39. The second control board 37 is, for example, a sensor board, and has a magnetic sensor such as a Hall IC that outputs a signal according to the rotational position of the motor 30 mounted thereon.

[0023] As shown in FIGS. 1, 2 and 5, the work machine 1 is provided in front of the motor housing portion 11 with, in that order from the rear, a gear case 26, a clutch dial 27, a front case 28, and a chuck 29 as an output shaft.

[0024] The gear case 26 is fixed to the front of the motor housing 11 by screwing or the like. The clutch dial 27 is sandwiched between the gear case 26 and the front case 28 in the front-rear direction. The tightening torque is set by turning the clutch dial 27. The front case 28 is fixed to the gear case 26 by screwing or the like. The chuck 29 is connected to the output side of the reduction mechanism 50, and holds a tool tip (not shown), such as a bit.

[0025] The problem of the comparative example shown in Fig. 5 will be described. The solid arrows in Fig. 5 indicate the main flow of the airflow generated by the fan 35, that is, the flow of the airflow that enters the housing 10 from the air window 14 shown in Fig. 4 and the like and is discharged to the outside of the housing 10 from the air window 16 shown in Fig. 1 and the like. The air passage through which the airflow passes inside the housing 10 is connected from the air window 14, which is an air intake provided at a position below the handle part 12, through the inside of the handle part 12 and the inside of the motor housing chamber 11, to the air window 16, which is an exhaust port provided in the motor housing part 11. The dashed arrows in Fig. 5 indicate the flow of the airflow generated by the fan 35 that enters the housing 10 through the gap between the shift knob 21 and the housing 10.

[0026] The air taken in through ventilator 14 provided in battery pack mounting section 13 cools first control board 23 and board case 24, then flows upward through handle section 12, cools second control board 37 and motor 30, and is exhausted through ventilator 16. Air flowing in from the gap between shift knob 21 and housing 10 comes into contact with only a part of the rear of motor 30 before being exhausted, and has no cooling effect on first control board 23 and board case 24, and the cooling effect on motor 30 is also small.

[0027] From the viewpoint of cooling the first control board 23 and the board case 24, it is desirable to have a large flow rate per unit time of outside air entering the housing 10 through the air window 14 (hereinafter, "air flow rate"). In the comparative example of FIG. 5, a large amount of air enters the housing 10 through the gap between the shift knob 21 and the housing 10, which results in a small amount of air entering the housing 10 through the air window 14, and thus a small cooling function for the first control board 23 and the board case 24. The working machine 1 of this embodiment is intended to solve these problems.

[0028] As shown in Fig. 6, the work machine 1 has a first wall portion 41 and a second wall portion 42 in the motor accommodating portion 11. The first wall portion 41 and the second wall portion 42 are preferably part of the housing 10. That is, the housing 10 preferably has the first wall portion 41 and the second wall portion 42. This reduces the number of manufacturing steps, and can reduce manufacturing costs and manufacturing time.

[0029] The first wall portion 41 is perpendicular to the front-rear direction and overlaps with at least a part of the area of ​​the shift knob 21 projected rearward. The first wall portion 41 is located between the shift knob 21 and the fan 35 in the front-rear direction. The first wall portion 41 constitutes a first partition portion that suppresses airflow from passing through the gap between the shift knob 21 and the housing 10. The first wall portion 41 that constitutes the first partition portion is configured to separate the shift knob 21, which is the operating portion, from the air passage inside the housing 10.

[0030] The second wall portion 42 is perpendicular to the up-down direction and overlaps at least a part of the area obtained by projecting downward the range of motion R in the front-rear direction of the rear end portion of the shift knob 21. The second wall portion 42 extends forward from the lower part of the first wall portion 41. The second wall portion 42 constitutes a first partition portion that prevents airflow from passing through the gap between the shift knob 21 and the housing 10 and separates at least a part of the space between the shift knob 21 and the outer periphery of the motor 30. The second wall portion 42 that constitutes the first partition portion is configured to separate the air passage inside the shift knob 21, which is the operating portion, and the housing 10.

[0031] 6 indicate the flow of air actually generated by fan 35. The dashed arrows indicate the flow of air that would flow in through the gap between shift knob 21 and housing 10 in the absence of second wall portion 42. It can be seen that the presence of second wall portion 42 guides the air flowing in through the gap forward, causing it to come into contact with the outer periphery of motor 30 further forward than in the absence of second wall portion 42 and flow rearward.

[0032] This embodiment provides the following advantageous effects.

[0033] (1) As shown in Fig. 6, air flowing in through the gap between the shift knob 21 and the housing 10 is guided forward by the second wall portion 42 and then comes into contact with the outer periphery of the motor 30. Therefore, compared to a case in which the second wall portion 42 is not provided, the contact area between the air flowing in through the gap and the outer periphery of the motor 30 is increased, thereby improving the cooling performance for the motor 30.

[0034] (2) Air flowing in through the gap between the shift knob 21 and the housing 10 bypasses the front of the second wall portion 42, increasing flow resistance. This makes it possible to reduce the amount of air flowing in through the gap compared to when the second wall portion 42 is not present. This makes it possible to increase the amount of air taken in through the air window 14 of the battery pack mounting portion 13, thereby increasing the flow rate of air coming into contact with the first control board 23, the board case 24, the second control board 37, and the motor 30, and improving the cooling capacity.

[0035] (Embodiment 2) Fig. 7 is a left sectional view of a main part of a working machine according to a second embodiment of the present invention. This working machine is obtained by extending the second wall portion 42 of the first embodiment shown in Fig. 6 forward. In this embodiment, the front end portion of the second wall portion 42 is located forward of the stator 38, the rotor 39, and the second control board 37. In other words, the second wall portion 42 constituting the first partition portion extends to one side beyond one end portion of the stator 38 in the axial direction of the motor 30.

[0036] According to this embodiment, the air flowing in from the gap between the shift knob 21 and the housing 10 is guided forward of the stator 38, the rotor 39, and the second control board 37 by the second wall portion 42, and then flows toward the motor shaft 31, cooling the second control board 37, the stator 38, and the rotor 39. A part of the air flowing in from the gap is guided by the second wall portion 42 to the inside of the motor 30 (the inside of the stator 38). Therefore, compared to a case where the second wall portion 42 is not provided, the air flowing in from the gap can be effectively used to cool the second control board 37 and the motor 30, and the cooling performance for the second control board 37 and the motor 30 can be improved. This embodiment is particularly effective when electronic components that generate high heat are mounted on the second control board 37.

[0037] Moreover, since second wall portion 42 is extended forward compared to embodiment 1, the flow resistance is further increased by detouring the front of second wall portion 42, and the amount of air flowing in through the gap can be further reduced. Therefore, the amount of air taken in through air window 14 of battery pack mounting portion 13 can be further increased, and the flow rate of air contacting first control board 23, board case 24, second control board 37, and motor 30 can be further increased, and the cooling capacity can be further improved.

[0038] (Embodiment 3) FIG. 8 is a left sectional view of a main part of a working machine according to a third embodiment of the present invention. This working machine is obtained by adding a third wall 43 as a first cover to the working machine according to the second embodiment shown in FIG. The third wall 43 is preferably a part of the housing 10. The third wall 43 is perpendicular to the front-rear direction and extends downward from the front of the second wall 42. The third wall 43 is located forward of the stator 38, the rotor 39, and the second control board 37. The third wall 43 will be further described in the fourth embodiment described later. The third wall 43 constitutes a first partition that suppresses airflow from passing through the gap between the shift knob 21 and the housing 10. The third wall 43 that constitutes the first partition is configured to separate the air passage inside the shift knob 21, which is an operating part, and the housing 10.

[0039] According to this embodiment, the first wall portion 41, the second wall portion 42, and the third wall portion 43 can prevent air from entering through the gap between the shift knob 21 and the housing 10, or can greatly reduce the amount of airflow through the gap. This makes it possible to greatly increase the amount of air taken in through the air window 14 of the battery pack mounting portion 13, increase the flow rate of air contacting the first control board 23, the board case 24, the second control board 37, and the motor 30, and improve the cooling capacity.

[0040] (Embodiment 4) 9 to 12 relate to a work machine according to a fifth embodiment of the present invention. This work machine is obtained by adding a fourth wall portion 44 to the work machine of the third embodiment shown in FIG. 8. The fourth wall portion 44 is preferably a part of the housing 10. The fourth wall portion 44 is perpendicular to the front-rear direction, is located below the stator 38, and constitutes a second partition portion that prevents airflow from passing between the lower portion of the stator 38 and the inner surface of the housing 10.

[0041] 9 indicate the airflow actually generated by the fan 35. The dashed arrows indicate the airflow that would exist if the fourth wall portion 44 were not present.

[0042] As shown in FIG. 11, the motor spacer 34 and the rear case 36 are fixed to the rear of the gear case 26 by screws or the like. The motor spacer 34 has a bearing holder 33 that supports a bearing 32 that supports a front part of the motor shaft 31. The motor spacer 34 and the rear case 36, together with the gear case 26, house the reduction gear mechanism 50 shown in FIG. 5 and the like. The shift knob 21 switches the reduction ratio of the reduction gear mechanism 50 shown in FIG. 5 and the like by rotating a shift arm 54 that appears in FIG. 11. As shown in FIG. 10, a shift knob holder 46 is provided on the upper part of the motor housing part 11. The shift knob holders 46 on the left and right parts of the housing are butted against each other to support the shift knob 21 by sandwiching it from the left and right directions.

[0043] 10 and 12, the third wall portion 43 has a semicircular cutout portion 45. The semicircular cutout portions 45 on the left and right parts of the housing are butted together to form a circular through hole. The inner edge of the cutout portion 45 runs along the outer circumferential surface of the bearing holder 33 and is close to or in contact with the outer circumferential surface. The third wall portion 43 is located or extends within the range in which the bearing 32 and the bearing holder 33 are present in the front-rear direction.

[0044] According to this embodiment, compared to the case where the fourth wall portion 44 is not present, the amount of air that rises within the handle portion 12 and passes between the lower part of the stator 38 and the inner surface of the housing 10 and is sucked into the fan 35 is reduced, and much of the air that has risen within the handle portion 12 is guided between the stator 38 and rotor 39 and the second control board 37, thereby improving the cooling performance for the second control board 37, the stator 38, and the rotor 39.

[0045] (Embodiment 5) Fig. 13 is a plan view of a working machine according to a fifth embodiment of the present invention. Fig. 14 is a plan view of the shift knob 21 of Fig. 13. The working machine of this embodiment is configured such that a dustproof rib 48 is provided as a second cover portion on the upper part of the housing 10 in any one of the first to fourth embodiments. The dustproof rib 48 covers the upper part of the through hole 22 of the shift knob 21 that appears in Figs. 2 and 14. In other words, the dustproof rib 48 covers an opening (upper opening) of the through hole 22 that is located on the outer side in the radial direction of the motor 30.

[0046] As shown in FIG. 14, the shift knob 21 has a flat base 56 perpendicular to the up-down direction, a knob portion 57 protruding upward from the top surface of the base 56, and a spring portion 58 provided on each of the left and right sides of the base 56 and extending in the front-rear direction. A protrusion 25 is provided as an engagement portion at the center (middle portion) in the front-rear direction of the spring portion 58. The spring portion 58 is rail-engaged with a groove (not shown) on the housing side. The protrusion 25 engages with a recess (not shown) on the housing side when the shift knob 21 is at a predetermined position in the front-rear direction relative to the housing, thereby determining the position of the shift knob 21. The through hole 22 is provided to allow the spring portion 58 to be elastically deformable in the left-right direction.

[0047] According to this embodiment, the dustproof rib 48 covers the upper part of the through hole 22, so that dustproofness is improved compared to the case where the through hole 22 is exposed to the outside air when viewed from above as shown in FIG. 2. The above-mentioned second wall portion 42 and third wall portion 43 suppress the inflow of air from the gap between the shift knob 21 and the housing 10, while suppressing the flow of dust into the inside of the housing, so that dust is likely to accumulate in the space above the second wall portion 42, that is, the movable space of the shift knob 21. As a result, the movement of the shift knob 21 in the front-rear direction may be hindered, and the operability may be reduced. By providing the dustproof rib 48 as in this embodiment, the inflow of dust into the movable space of the shift knob 21 can be prevented, and the deterioration of the operability of the shift knob 21 can be suppressed. Note that, if the shift knob 21 does not have a hole penetrating in the vertical direction, a similar effect can be obtained by providing a dustproof rib so as to cover the entire outer periphery of the shift knob 21.

[0048] (Embodiment 6) 15 is a left sectional view of a main part of a working machine according to a sixth embodiment of the present invention. In this working machine, a fan 135 is located in front of a motor 130, and a ventilating window 114 serving as an air intake and a control board 137 are located behind the motor 130. The fan 135 is a centrifugal fan, and a ventilating window serving as an exhaust port is provided to the side of the fan 135. A shift knob 121 is provided on the upper part of the motor accommodating section 111 of the housing. The first wall portion 141 and the second wall portion 142 correspond to the first wall portion 41 and the second wall portion 42 of the above-mentioned embodiment. The second wall portion 142 extends forward until it approaches the fan 135 in the front-rear direction.

[0049] 15 indicates the flow of air actually generated by fan 135. The dashed arrow indicates the flow of air that would flow in from the gap between shift knob 121 and the housing if second wall portion 142 were not present, and that would hardly contribute to cooling motor 130 or control board 137.

[0050] According to this embodiment, the presence of second wall portion 142 can reduce the flow rate of air flowing in through the gap between shift knob 121 and the housing, thereby improving the cooling performance for control board 137 and motor 130.

[0051] Although the present invention has been described above by taking the embodiment as an example, the present invention is not limited to the embodiment. Various modifications can be made to each of the details specifically described in the embodiment within the scope of the claims.

[0052] The working machine of the present invention is not limited to the driver drill exemplified in the embodiment, and may be another type such as an impact driver. The motor may be a brushed motor. A fourth wall portion 44 shown in FIG. 9 may be added to the configuration of FIG. 6 or FIG. 7. [Explanation of symbols]

[0053] 1...working machine, 10...housing, 11...motor housing (first housing), 12...handle portion, 13...battery pack mounting portion (second housing), 14...ventilation window (intake port), 15...tail cover, 16...ventilation window (exhaust port), 17...trigger switch (indicator portion), 19...forward / reverse switch, 21...shift knob (operation portion), 22...through hole, 23...first control board, 24...board case, 25...projection (engagement portion), 26...gear case, 27...clutch dial, 28...front case, 29...chuck, 30...motor, 31...motor shaft , 32...bearing, 33...bearing holding portion, 34...motor spacer, 35...fan, 36...rear case, 37...second control board (sensor board), 38...stator, 39...rotor, 41...first wall portion (first partition portion), 42...second wall portion (first partition portion), 43...third wall portion (first partition portion, first cover portion), 44...fourth wall portion (second partition portion), 45...cutout portion, 46...shift knob holding portion, 47, 48...dustproof rib (second cover portion), 50...reduction mechanism, 54...shift arm, 56...base, 57...knob portion, 58...spring portion.

Claims

1. A motor having a motor shaft extending in a front-rear direction, a stator, and a rotor; A fan driven by the motor to generate an airflow; a housing including a motor housing portion that houses the motor and the fan, a handle portion that extends downward from the motor housing portion, and an air passage through which the airflow passes; An instruction unit that instructs the motor to be driven or stopped; an operation unit separate from the instruction unit, at least a portion of the operation unit being disposed radially outward of the stator and movably supported in the motor accommodating portion so as to be operable from the outside; In a work machine having a first partition configured to separate the operation unit from an outer periphery of the stator on the radially outer side of the stator and to separate the operation unit from the air passage, the first partition preventing the airflow from entering the housing through a gap between the operation unit and the housing and flowing into the air passage; and / or a second partition preventing the airflow from passing between a lower portion of the stator and an inner surface of the housing. A work machine characterized by:

2. The work machine according to claim 1, The first partition portion includes a second wall portion extending in an axial direction of the motor and partitioning at least a portion between the operation portion and an outer periphery of the motor. A work machine characterized by:

3. The work machine according to claim 2, The first partition further includes a first wall portion extending upward from the second wall portion, the operation unit is provided in a position forward of the first wall portion and above the second wall portion, and the stator is provided in a position below the second wall portion. A work machine characterized by:

4. The working machine according to claim 3, The first partition further includes a third wall extending downward from the second wall, The stator is provided at a position lower than the second wall portion and rearward of the third wall portion. A work machine characterized by:

5. The work machine according to claim 2, The motor accommodating portion has a dustproof rib that covers at least an upper portion of a rear portion of the operating portion, and the first wall portion extends upward from the second wall portion and is connected to the dustproof rib. A work machine characterized by:

6. The work machine according to claim 2, the second wall portion extends to one side beyond one end of the stator in the axial direction of the motor; A work machine characterized by:

7. The work machine according to claim 6, the first partition portion further includes a third wall portion extending from the second wall portion in a direction intersecting with the axial direction of the motor, The third wall portion extends from one end of the second wall portion in the axial direction and is configured as a first cover portion that covers one side of the stator in the axial direction. A work machine characterized by:

8. The work machine according to claim 1, a speed reduction mechanism for reducing the rotation speed of the motor; an output shaft to which the rotation of the motor reduced by the reduction mechanism is transmitted, The operation unit is configured as a gear shift operation unit that changes a reduction ratio, which is a ratio of the rotation speed of the output shaft to the rotation speed of the motor. A work machine characterized by:

9. A work machine according to claim 4 or 7, a bearing for supporting a front portion of the motor shaft; and a bearing holder for supporting the bearing, The third wall portion is located within a range in which the bearing and the bearing holder are present in the front-rear direction. A work machine characterized by:

10. The work machine according to claim 1, the housing includes a second housing portion provided at an end of the handle portion opposite the motor housing portion and having an air window; A control board is housed in the second housing portion and has a switching element for supplying power to the motor mounted thereon. A work machine characterized by:

11. The work machine according to claim 9, the housing is a combination of a left housing and a right housing, the left housing and the right housing sandwiching and supporting the operation unit from the left and right directions, the third wall portion has a first semicircular notch portion formed in the left housing and a second semicircular notch portion formed in the right housing, and inner edges of the first notch portion and the second notch portion are in close proximity to or in contact with an outer circumferential surface of the bearing holder; A work machine characterized by:

12. The work machine according to claim 1, the fan is located on the other side of the stator in an axial direction of the motor and is configured to draw in airflow from one side in the axial direction; At least a portion of the operation unit is located above the stator, The second partition includes a fourth wall portion below the stator, the fourth wall portion suppressing the airflow from passing between a lower portion of the stator and an inner surface of the housing. A work machine characterized by:

13. The work machine according to claim 1, The operation unit includes: an engagement portion that engages with the housing at a predetermined relative position; a through hole that allows the engagement portion to be elastically deformed; The housing has a second cover portion that covers an opening of the through hole that is located on an outer side in a radial direction of the motor. A work machine characterized by:

14. The work machine according to claim 1, The air passage is configured to connect an air intake provided below the handle portion to an exhaust port provided in the motor housing portion through the inside of the handle portion and the inside of the motor housing portion. A work machine characterized by:

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