JP7540499B2 - Work Machine - Google Patents

Description

The present invention relates to a work machine.

The portable electric cutting machine (working machine) described in Patent Document 1 below is provided with a fan that rotates when driven by a motor, and a control unit for controlling the driving of the motor is disposed to the side of the fan. As a result, when the motor is driven, cooling air generated by the rotation of the fan flows into the control unit, and the motor and heat-generating components (cooled parts) such as FETs mounted on the control unit can be cooled by the cooling air.

JP 2013-193133 A

However, there is still a demand for improved cooling performance for heat-generating components. In particular, in recent years, there has been a trend for heat-generating components to become hotter, for example, to accommodate higher motor output and higher load operations. For this reason, it is desirable for work machines to have a structure that can more effectively cool heat-generating components.

The present invention takes into consideration the above facts and aims to provide a work machine that can improve the cooling performance for the cooled part (heat-generating component).

One or more embodiments of the present invention include a working machine comprising a housing having an intake port and an exhaust port, a motor accommodated in the housing, a fan accommodated in the housing and rotated by the drive of the motor to generate cooling air inside the housing, and a control unit that controls the motor and is cooled by the cooling air , wherein the control unit is accommodated in the housing so as to be positioned to the side of the motor and partitions a space in which the motor is accommodated, and the cooling air includes upstream cooling air that is sucked into the interior of the housing from the intake port and flows into the fan, and downstream cooling air that flows out of the fan and is exhausted to the outside of the housing from the exhaust port, and the control unit is cooled by the upstream cooling air and the downstream cooling air.

One or more embodiments of the present invention are a work machine in which the housing has a first space through which the upstream cooling air passes and a second space through which the downstream cooling air passes, and the control unit is exposed to the first space and the second space.

One or more embodiments of the present invention are directed to a work machine in which the housing is constituted by a plurality of split housings, and a clamping portion that clamps the control unit is formed in each of the split housings.

One or more embodiments of the present invention are a work machine in which the housing is provided with a straightening section that separates the first space from the second space and straightens the upstream cooling air and guides it toward the second space, and the straightening section is formed with an exposure section for exposing a portion of the control section to the second space.

One or more embodiments of the present invention are a work machine in which the fan is arranged in the second space, a guide hole is formed in the straightening section connecting the first space and the second space, and the fan and the guide hole are arranged opposite each other in the axial direction of the fan.

In one or more embodiments of the present invention, the control unit is configured to include a control board connected to the motor and a box-shaped case that houses the control board and is open on one thickness side, and the work machine cools the bottom wall of the case with the cooling air.

One or more embodiments of the present invention are a work machine in which the control unit is arranged in the first space and the air intake is arranged on the other side of the case in the thickness direction relative to the bottom wall of the case.

One or more embodiments of the present invention are a work machine in which the control unit separates the first space from the second space.

One or more embodiments of the present invention are a work machine in which the bottom wall of the case is exposed to the first space and an opening of the case is open toward the second space.

One or more embodiments of the present invention are directed to a work machine in which a portion of the control unit is disposed radially outside the fan, and the fan is configured as a centrifugal fan.

According to one or more embodiments of the present invention, the cooling performance for the cooled part can be improved.

FIG. 2 is a side view showing the saber saw according to the present embodiment as viewed from the right side. FIG. 2 is a side cross-sectional view showing the inside of the saber saw shown in FIG. 1 . 2 is a perspective view showing a state in which a control unit is sandwiched by the rear housing shown in FIG. 1, as viewed obliquely from the left front. FIG. 4 is an exploded perspective view of the rear housing and the control unit shown in FIG. 3 . 2 is a rear view showing a motor housing portion of the rear housing shown in FIG. 1 as viewed from the rear side. FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 5, showing an assembled state of the left split housing and the control unit as viewed from the left side. 7 is a cross-sectional view (cross-sectional view taken along line 7-7 in FIG. 1 ) seen from the front side, showing the inside of a motor housing portion of a rear housing shown in FIG. 1 . FIG. 3 is a perspective view showing the control unit shown in FIG. 2 as viewed from below. 3 is a side cross-sectional view for explaining the flow of cooling air inside the motor housing portion shown in FIG. 2. 10 is a side cross-sectional view for explaining the flow of cooling air in the modified example of the cooling structure shown in FIG. 9 . 10 is a side cross-sectional view for explaining the flow of cooling air in another modified example of the cooling structure shown in FIG. 9 . 12 is a cross-sectional view seen from the front for explaining the flow of cooling air in the other modified example shown in FIG. 11. FIG. FIG. 13 is a partially cutaway plan view showing an example in which the cooling structure is applied to a circular saw. FIG. 1 is a partially cutaway side cross-sectional view showing an example in which the cooling structure is applied to a hammer drill.

The following describes the saber saw 10 as a work machine according to this embodiment, with reference to the drawings. Note that the arrows UP, FR, and RH, as appropriate shown in the drawings, indicate the upper side, front side, and right side of the saber saw 10, respectively. In the following description, when the up-down, front-back, and left-right directions are used, they refer to the up-down, front-back, and left-right directions of the saber saw 10, unless otherwise specified.

The saber saw 10 is configured as a tool for cutting workpieces such as pipes. As shown in Figures 1 and 2, the saber saw 10 includes a housing 12 that forms the outer shell of the saber saw 10, and a motor 40 and a drive mechanism 50 housed inside the housing 12. The saber saw 10 also has a control unit 60 as a cooled part for controlling the motor 40. Furthermore, in the saber saw 10, a cooling structure S is applied around the control unit 60, and the control unit 60 is cooled by the cooling structure S. Each component of the saber saw 10 will be described below.

(Regarding the housing 12) The housing 12 is formed to be hollow and to have a generally horizontal P-shape in a side view. The housing 12 is configured to include a rear housing 13 constituting the rear part of the housing 12 and a front housing 14 constituting the front part of the housing 12. The rear housing 13 is configured as a housing part that houses the motor 40 described later, and the front housing 14 is configured as a housing part that houses the drive mechanism 50 described later. The front housing 14 has a resin front cover 14A, and a metal upper cover 14B and an under cover 14C located inside the front cover 14A. The upper cover 14B and the under cover 14C are assembled in the vertical direction to define a space that houses the drive mechanism 50. The operator can perform work while holding the front part (area with a small diameter) of the front cover 14A.

The rear housing 13 is composed of a pair of split housings 15 that are split in two in the left-right direction, and the rear housing 13 is formed by assembling the pair of split housings 15 together (see Figure 4). The rear end of the rear housing 13 is configured as a handle portion 13A, which extends in the vertical direction. A trigger 30 that can be pulled is provided at the upper end of the handle portion 13A, and a switch mechanism portion 31 is provided behind the trigger 30. The switch mechanism portion 31 has a switch (not shown) that is operated by the trigger 30, and the switch is electrically connected to the control portion 60, which will be described later.

A battery pack 32 is removably attached to the lower end of the rear end of the rear housing 13. The battery pack 32 is electrically connected to the control unit 60, which will be described later, and supplies power to the motor 40, which will be described later.

As shown in Figures 3 to 7, the front part of the rear housing 13, excluding the upper end, is configured as a motor housing section 16 for accommodating the motor 40 described later. The motor housing section 16 is formed in a generally bottomed cylindrical shape that is open to the front side. Inside the motor housing section 16, a fan guide 17 is provided in the front end part as a straightening section. The fan guide 17 is formed in a plate shape with the plate thickness direction in the front-rear direction and extends from the outer peripheral wall of the split housing 15 to the left-right center side of the saber saw 10. The tip ends of the fan guides 17 formed in the split housing 15 are butted against each other in the left-right center of the motor housing section 16. As a result, the inside of the motor housing section 16 is divided into front and rear by the fan guide 17. Specifically, the inside of the motor housing section 16 is divided into a first space 16A that constitutes the rear part of the motor housing section 16 and a second space 16B that constitutes the front end part of the motor housing section 16 (see Figure 6).

A circular guide hole 17A is formed through the fan guide 17 at approximately the center. As a result, the first space 16A and the second space 16B are connected by the guide hole 17A. In addition, a front fixing portion 17B for fixing the control unit 60 described later is formed at the lower end of the fan guide 17. The front fixing portion 17B is formed in an approximately concave shape that protrudes forward in a side view and opens to the rear. The upper wall of the front fixing portion 17B is configured as an inclined wall 17C that inclines downward as it approaches the front side in a side view. An exposure hole 17D is formed through the inclined wall 17C at the center in the left-right direction as an exposure portion, and the exposure hole 17D is formed in an approximately rectangular shape with the left-right direction as the longitudinal direction when viewed from the plate thickness direction of the inclined wall 17C.

In addition, a first rear fixing portion 18 (see FIG. 4) for fixing the control unit 60 described later is formed at the lower end of the right rear end of the motor housing portion 16. The first rear fixing portion 18 is formed in a substantially U-shaped plate shape that is open to the front side in a side view, and extends from the right wall of the motor housing portion 16 toward the center in the left-right direction. In addition, a second rear fixing portion 19 (see FIG. 6 and FIG. 7) for fixing the control unit 60 described later is formed at the lower end of the left rear end of the motor housing portion 16. The second rear fixing portion 19 is formed in a substantially L-shaped plate shape that is open to the front and upper sides in a side view, and extends from the left wall of the motor housing portion 16 toward the center in the left-right direction. In addition, a fixing piece 20 (see FIG. 6 and FIG. 7) for fixing the control unit 60 described later is formed at the lower end of the left wall of the motor housing portion 16. The fixed piece 20 is formed in a generally rectangular plate shape with its thickness direction in the up-down direction, and extends from the left wall of the motor housing portion 16 toward the left-right center of the motor housing portion 16. Furthermore, a pair of front and rear clamping portions 21 (FIGS. 4 and 7) are formed at the lower ends of the left and right side walls of the motor housing portion 16 within the first space 16A, and the clamping portions 21 protrude from the left and right side walls of the motor housing portion 16 toward the left-right center of the motor housing portion 16 (FIGS. 4 and 7 only show the rear clamping portion 21).

A plurality of (eight in this embodiment) air intakes 22 (see FIG. 5) are formed through the rear wall of the motor housing section 16. The air intakes 22 are formed as elongated holes with the left-right direction as the longitudinal direction. As a result, the air intakes 22 communicate with the inside of the first space 16A and the outside of the motor housing section 16. The air intakes 22 are arranged in pairs in the vertical direction, and the paired air intakes 22 are respectively arranged at the upper end and lower end of the right and left parts of the rear wall of the motor housing section 16. The air intakes 22 are also arranged above the control section 60, which will be described later. A foreign object intrusion prevention rib 22A (see FIG. 6) protruding forward is formed on the lower edge of the air intake 22. The foreign object intrusion prevention rib 22A extends in the left-right direction, and the front end of the foreign object intrusion prevention rib 22A is bent upward in a side view.

Multiple exhaust ports 23 (12 in this embodiment) (see FIG. 3) are formed through the front end of the motor housing portion 16. The exhaust ports 23 are formed as elongated holes with the circumferential direction of the motor housing portion 16 as the longitudinal direction. As a result, the exhaust ports 23 communicate with the inside of the second space 16B and the outside of the motor housing portion 16. Furthermore, the exhaust ports 23 are arranged in pairs in the front-to-rear direction, and the paired intake ports 22 are arranged side by side in the left-right direction on the bottom wall of the motor housing portion 16. Furthermore, the paired exhaust ports 23 are arranged side by side in the up-down direction on the left and right side walls of the motor housing portion 16.

(Regarding the motor 40) As shown in FIG. 2 and FIG. 9, the motor 40 is accommodated in the first space 16A of the motor housing portion 16 of the housing 12. The motor 40 includes a drive shaft 41, a rotor 42, a stator 43, and a motor board 45. The drive shaft 41 is formed in a substantially cylindrical shape with the axial direction being the front-rear direction, and is arranged coaxially with the guide hole 17A. The rear end of the drive shaft 41 is rotatably supported by a first bearing 33 fixed to the motor housing portion 16. The drive shaft 41 is inserted through the guide hole 17A of the fan guide 17, and the front end of the drive shaft 41 is arranged in the front housing 14. The front end portion of the drive shaft 41 is rotatably supported by a second bearing 34 provided in the front housing 14. A pinion gear 41A is formed on the outer periphery of the front end of the drive shaft 41.

The rotor 42 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction and is configured to be able to rotate integrally with the drive shaft 41 on the radial outside of the drive shaft 41. The stator 43 is formed in a generally cylindrical shape with its axial direction extending in the front-to-rear direction and is disposed on the radial outside of the rotor 42. The stator holder 44 of the stator 43 is held by being sandwiched in the left-to-right direction by motor retaining ribs 24 (see Figures 4, 6, and 7) formed on the left and right side walls of the motor housing portion 16.

The motor board 45 is formed in a generally annular plate shape with the plate thickness direction being the front-to-rear direction, and is fixed to the stator holder 44 on the rear side of the rotor 42 and the stator 43. One end of the coil wound around the stator holder 44 is connected to the motor board 45.

(Regarding the drive mechanism 50) As shown in FIG. 2, the drive mechanism 50 is housed in the front housing 14 (an area defined by the upper cover 14B and the under cover 14C). The drive mechanism 50 includes a bevel gear 51, a motion conversion pin 52, and a plunger 53. The bevel gear 51 is provided in front of the drive shaft 41 of the motor 40 so as to be rotatable with the vertical direction as its axial direction, and is meshed with the pinion gear 41A of the motor 40. The motion conversion pin 52 is formed in a cylindrical shape with the vertical direction as its axial direction, and is fixed to the bevel gear 51 at a position eccentric to the rotation axis of the bevel gear 51. The upper end of the motion conversion pin 52 protrudes upward from the bevel gear 51.

The plunger 53 is formed in a generally cylindrical shape with its axial direction being the front-to-rear direction. The plunger 53 is supported by the front housing 14 above the bevel gear 51 so as to be able to reciprocate in the front-to-rear direction. A connecting portion 54 is formed at the rear end of the plunger 53, and the connecting portion 54 is formed in a groove shape that is open downward and extends in the left-to-right direction. The upper end of the motion conversion pin 52 is inserted into the connecting portion 54, connecting the bevel gear 51 and the plunger 53. As a result, when the motor 40 is driven and the bevel gear 51 rotates, the plunger 53 reciprocates in the front-to-rear direction.

A blade holder 55 is provided at the front end of the plunger 53, and a blade 56 is attached to the blade holder 55. The blade 56 is formed in a generally long plate shape with the longitudinal direction being the front-to-rear direction and the plate thickness direction being the left-to-right direction. The rear end of the blade 56 is attached to the blade holder 55, and the blade 56 is disposed on the front side of the front housing 14. A cutting edge 56A is formed at the lower end of the blade 56. As a result, the blade 56 moves back and forth in the front-to-rear direction, causing the blade 56 to cut the workpiece.

(Regarding the control unit 60) As shown in Figures 2, 4, 6, and 8, the control unit 60 is housed in the lower end of the first space 16A of the motor housing portion 16. The control unit 60 is configured to include a control board 62 and a case 61 that houses the control board 62. The case 61 is formed in a relatively shallow rectangular box shape with the thickness direction being the up-down direction. The case 61 is also open to one side in the thickness direction (the lower side). As a result, the case 61 is configured to include a bottom wall 61A that forms the upper end of the case 61, and a side wall 61B that extends downward from the outer periphery of the bottom wall 61A. The upper end of the side wall 61B is formed with a case inclined portion 61C. The case inclined portion 61C is inclined toward the inside of the case 61 as it moves upward and is connected to the bottom wall 61A.

The case 61 is sandwiched in the left-right direction by the split housing 15 of the rear housing 13 and fixed to the motor housing part 16. Specifically, the left and right side walls 61B of the case 61 are sandwiched in the left-right direction by the left and right clamping parts 21 of the motor housing part 16. As a result, the left-right movement of the case 61 is restricted by the clamping parts 21. The front end of the case 61 is disposed inside the front fixing part 17B of the motor housing part 16, and the rear end of the case 61 is disposed inside the first rear fixing part 18 and above the lower wall of the second rear fixing part 19. The fixing piece 20 of the motor housing part 16 is disposed above the left end of the bottom wall 61A of the case 61. As a result, the front fixing part 17B, the first rear fixing part 18, the second rear fixing part 19, and the fixing piece 20 restrict the up-down movement of the case 61.

The case 61 is disposed below the stator 43 of the motor 40 at a distance, and is disposed below the intake port 22 of the motor housing portion 16. As a result, a cooling air passage 70 (see Figures 7 and 9) is formed between the motor 40 and the case 61. That is, the bottom wall 61A of the case 61 is accommodated in the first space 16A of the motor housing portion 16 so as to form part of the wall of the cooling air passage 70. Also, an opening 61D of the case 61 opens on the opposite side of the bottom wall 61A to the cooling air passage 70, the intake port 22, and the guide hole 17A. Furthermore, the rear end of the cooling air passage 70 is connected to the intake port 22, and the front end of the cooling air passage 70 is connected to the guide hole 17A.

In addition, when the case 61 is fixed to the motor housing portion 16, a portion of the case inclined portion 61C of the case 61 is exposed into the second space 16B through the exposure hole 17D of the fan guide 17 in the motor housing portion 16.

The control board 62 is formed in a generally rectangular plate shape with the thickness direction being the up-down direction. The control board 62 is housed in the case 61 and fixed to the case 61. A plurality (six in this embodiment) of switching elements (FETs) 63 (which are broadly understood to be heat-generating components) are provided on the underside of the control board 62.

(Regarding the fan 72) The saber saw 10 has a fan 72 that generates cooling air AR that cools the control unit 60. The fan 72 is fixed to the front end portion of the drive shaft 41 of the motor 40 so as to be rotatable together with the control unit 60, and is disposed in front of the fan guide 17 and within the second space 16B of the motor housing portion 16. In other words, most of the control unit 60 is disposed between the intake port 22 of the motor housing portion 16 and the fan 72, and a part (front end portion) of the control unit 60 is disposed between the fan 72 and the exhaust port 23 of the motor housing portion 16.

The fan 72 is configured as a centrifugal fan and generates an air flow that causes the air behind the fan 72 to flow radially outward from the fan 72. As a result, inside the motor housing part 16, a cooling air AR is generated that is sucked into the motor housing part 16 from the intake port 22 and discharged to the outside of the motor housing part 16 from the exhaust port 23. Specifically, the cooling air AR includes an upstream cooling air AR1 that is sucked into the first space 16A from the intake port 22 and into the second space 16B and flows into the fan 72, and a downstream cooling air AR2 that flows out radially outward from the fan 72 in the second space 16B and is discharged to the outside of the motor housing part 16 from the exhaust port 23. That is, the air flow (intake air) from the intake port 22 to the fan 72 is the upstream cooling air AR1, and the air flow (discharge air) from the fan 72 to the exhaust port 23 is the downstream cooling air AR2.

Then, as will be described in detail later, the upstream cooling air AR1 sucked into the first space 16A from the intake port 22 passes through the cooling air passage 70 and flows toward the guide hole 17A along the rear surface of the fan guide 17. In other words, the fan guide 17 is configured to function as a guide section that guides the upstream cooling air AR1 flowing within the first space 16A to the fan 72.

(Effects and Effects) Next, the effects and effects of this embodiment will be explained.

In the saber saw 10 configured as described above, the motor 40 is driven by pulling the trigger 30. When the motor 40 is driven, the driving force of the motor 40 is transmitted to the plunger 53 of the drive mechanism 50, causing the plunger 53 to reciprocate in the front-to-rear direction. This causes the blade 56 attached to the plunger 53 to reciprocate in the front-to-rear direction together with the plunger 53. Therefore, the reciprocating blade 56 can cut the workpiece, such as a pipe.

When the motor 40 is driven, the fan 72 rotates around the axis of the drive shaft 41 together with the drive shaft 41 of the motor 40, generating an airflow that causes the air on the rear side (motor 40 side) of the fan 72 to flow radially outward from the fan 72. As a result, as shown in FIG. 9, the upstream cooling air AR1 is sucked into the first space 16A from the intake port 22 of the motor housing part 16. The intake port 22 is also connected to the rear end of the cooling air passage 70. Therefore, the upstream cooling air AR1 sucked into the upper part of the first space 16A hits the motor board 45 of the motor 40, flows downward (to the cooling air passage 70 side) along the rear surface of the motor board 45, and is also flowed into the rear end side of the cooling air passage 70. The upstream cooling air AR1 sucked into the lower part of the first space 16A is directly flowed into the rear end side of the cooling air passage 70.

The upstream cooling air AR1 that flows into the rear end of the cooling air passage 70 flows forward within the cooling air passage 70 along the upper surface of the bottom wall 61A of the case 61 of the control unit 60. That is, the upstream cooling air AR1 flows within the cooling air passage 70 while cooling the case 61. When the upstream cooling air AR1 reaches the front end of the cooling air passage 70, it hits the lower end of the fan guide 17 and flows upward along the rear surface of the fan guide 17. The upstream cooling air AR1 that flows upward along the fan guide 17 is sucked into the second space 16B through the guide hole 17A and flows into the fan 72.

The upstream cooling air AR1 sucked into the fan 72 flows out radially outward from the fan 72 as downstream cooling air AR2. The downstream cooling air AR2 flowing out from the fan 72 is exhausted from the exhaust port 23 to the outside of the motor housing part 16. At this time, the downstream cooling air AR2 flowing downward from the fan 72 flows downward along the front surface of the fan guide 17. The downstream cooling air AR2 that reaches the lower end of the fan guide 17 flows diagonally downward and forward along the inclined wall 17C of the fan guide 17 and the case inclined part 61C exposed from the exposure hole 17D, and is exhausted from the lower exhaust port 23 to the outside of the motor housing part 16. That is, the downstream cooling air AR2 flows toward the exhaust port 23 while cooling the front end of the case 61.

As described above, in the saber saw 10 of this embodiment, the motor 40, the fan 72, and the control unit 60 are housed in the motor housing portion 16 of the housing 12, and the motor housing portion 16 is formed with an intake port 22 and an exhaust port 23. As a result, cooling air AR is generated in the motor housing portion 16, which is sucked in through the intake port 22 and exhausted through the exhaust port 23. In detail, upstream cooling air AR1 is generated, which flows into the motor housing portion 16 from the intake port 22 and flows into the fan 72, and downstream cooling air AR2 is generated, which flows out of the fan 72 and exhausts to the outside of the motor housing portion 16 through the exhaust port 23. In this embodiment, the control unit 60 having the switching element 63 that generates heat during operation is cooled by the upstream cooling air AR1 and the downstream cooling air AR2. As a result, the control unit 60 can be cooled more efficiently than in a configuration in which the control unit 60 is cooled by one of the upstream cooling air AR1 and the downstream cooling air AR2. Therefore, the cooling performance for the control unit 60 can be improved. The air that has just entered the motor housing portion 16 from the intake port 22 has a low temperature and therefore a high cooling effect, and the rear end portion of the control portion 60 is cooled by the upstream portion of the upstream cooling air AR1 (air before cooling the motor 40), so the cooling effect is high. Furthermore, the downstream cooling air AR2 tends to flow fast, and the control portion 60 can also be cooled suitably by blowing the high-speed discharge air (air after cooling the motor 40) onto the control portion 60. In other words, the present invention is characterized by a cooling configuration that utilizes the advantages of both the intake air and the discharge air, by blowing the relatively low-temperature intake air onto the control portion 60 and also blowing the high-speed discharge air onto the control portion 60. Furthermore, if the control unit 60 is cooled with only the upstream cooling air AR1 or the downstream cooling air AR2, there is a risk that the housing will become unnecessarily large or the structure will become more complex in order to form a sufficient flow path. However, by cooling with both the upstream cooling air AR1 and the downstream cooling air AR2 as in this embodiment, design freedom is obtained and the control unit 60 can be cooled appropriately without making the housing larger or more complex.

The motor housing portion 16 also has a first space 16A through which the upstream cooling air AR1 passes and a second space 16B through which the downstream cooling air AR2 passes, and the control unit 60 is exposed to the first space 16A and the second space 16B. Specifically, the control unit 60 is disposed between the intake port 22 and the fan 72. Furthermore, a portion (front end) of the control unit 60 is exposed to the second space 16B by the exposure hole 17D of the fan guide 17, and is disposed between the fan 72 and the exhaust port 23. This allows the control unit 60 to be cooled by the upstream cooling air AR1 and the downstream cooling air AR2.

Furthermore, the motor housing portion 16 is provided with a fan guide 17 that divides the first space 16A and the second space 16B, and the upstream cooling air AR1 and the downstream cooling air AR2 are rectified by the fan guide 17. Specifically, the direction of the upstream cooling air AR1 flowing through the cooling air passage 70 is changed to the upper side by the fan guide 17, and the upstream cooling air AR1 flows upward along the rear surface of the fan guide 17 and is sucked into the second space 16B through the guide hole 17A. This allows the upstream cooling air AR1 to flow efficiently toward the second space 16B. In addition, the downstream cooling air AR2 discharged from the fan 72 flows downward along the front surface of the fan guide 17. Therefore, the front end of the control unit 60 can be cooled by the downstream cooling air AR2 while the fan guide 17 suppresses the backflow of the downstream cooling air AR2 toward the first space 16A.

Furthermore, the fan 72 is disposed in front of the guide hole 17A within the second space 16B. This allows the airflow generated by the fan 72 to efficiently discharge the upstream cooling air AR1 from the guide hole 17A to the second space 16B side and allow it to flow into the fan 72.

Furthermore, the first space 16A houses the motor 40 and the control unit 60, with the control unit 60 positioned radially outward (below) of the motor 40 at a distance. This allows a cooling air passage 70 to be formed between the motor 40 and the control unit 60 for passing the upstream cooling air AR1, and allows a part of the wall of the cooling air passage 70 to be formed by the case 61 of the control unit 60. Therefore, the upstream cooling air AR1 passing through the cooling air passage 70 can efficiently cool the control unit 60 and the motor 40.

The case 61 of the control unit 60 is formed in a generally box-like shape that is open downward, and the wall of the cooling air passage 70 is formed by the bottom wall 61A of the case 61. Specifically, the intake port 22 is arranged on the upper side of the case 61 (opposite the opening 61D). As a result, the upstream cooling air AR1 passing through the cooling air passage 70 moves forward along the upper surface of the bottom wall 61A to cool the control unit 60, and the upstream cooling air AR1 can be prevented from directly hitting the control board 62 in the case 61 and electronic elements such as the switching element 63 or wiring mounted on the control board 62. For this reason, for example, even if chips generated during the operation of the saber saw 10 flow into the first space 16A together with the upstream cooling air AR1, the chips can be prevented from hitting the control board 62 or electronic elements. Therefore, the cooling performance for the control unit 60 can be improved while improving the protection performance for the control board 62. In particular, when the workpiece is a metal, the protection performance for the control board 62 can be effectively improved.

In addition, since the upstream cooling air AR1 flows forward along the upper surface of the bottom wall 61A of the control unit 60, the upstream cooling air AR1 can flow smoothly in the cooling air passage 70. In addition, by dividing a part of the inside of the motor housing part 16 by the control unit 60, the space above the control unit 60 and the space below the control unit 60 can be divided, and the first space 16A can be easily formed. In other words, by attaching the control unit 60, it is possible to easily form an air passage for the upstream cooling air AR1, and it is not necessary to provide the motor housing part 16 with more structures (ribs, etc.) for forming an air passage than necessary. In addition, when forming a cooling air passage using the fan 72, which is a centrifugal fan, an intake air moving in the axial direction of the motor 40 and an exhaust air moving radially outward are usually formed. In this embodiment, the control unit 60 functions as a wall dividing the first space 16A and also functions as a wall dividing the second space 16B. In this way, the control unit 60 can be cooled by the upstream cooling air AR1 flowing in the axial direction and the downstream cooling air AR2 flowing radially outward, and an optimal cooling configuration for the control unit 60 can be realized with a simple configuration without making the cooling air turn around.

Furthermore, the case 61 of the control unit 60 is clamped from the outside in the left-right direction by the clamping portions 21 of the motor housing portion 16. Specifically, the left and right clamping portions 21 are positioned on the outside in the left-right direction of the intake port 22 and clamp the case 61 in the left-right direction. This allows the case 61 to be fixed by the clamping portions 21 without impeding the flow of the upstream cooling air AR1 in the cooling air passage 70.

(Modification 1 of the cooling structure S) Next, using FIG. 10, a modification 1 of the cooling structure S in the saber saw 10 will be described. The cooling structure S of the modification 1 is configured in the same manner as the present embodiment, except for the following points. That is, in the cooling structure S of the modification 1, a communication hole 17E is formed through the lower side of the front fixing portion 17B of the fan guide 17. As a result, the lower space of the control unit 60 and the second space 16B are connected by the communication hole 17E. That is, in the modification 1, the second space 16B expands to the lower space of the control unit 60. The space upstream of the second space 16B and the first space 16A are partitioned by the fan guide 17, and the space downstream of the second space 16B and the first space 16A are partitioned by the control unit 60. In addition, the exhaust port 23 formed in the lower wall of the motor housing portion 16 has been moved rearward compared to the present embodiment. Specifically, the exhaust port 23 is disposed below the rear end of the control unit 60. As a result, the rear end of the second space 16B is in communication with the outside of the motor housing portion 16 via the exhaust port 23 .

For this reason, in variant 1 of cooling structure S, the downstream cooling air AR2 flowing downward from the fan 72 flows downward along the front surface of the fan guide 17 and flows into the space below the control unit 60 through the communication hole 17E of the fan guide 17. The downstream cooling air AR2 flowing into the lower side of the control unit 60 flows rearward while cooling the lower side of the control unit 60, and flows out to the outside of the motor housing portion 16 through the exhaust port 23 below the control unit 60. Therefore, even in variant 1 of cooling structure S, the control unit 60 can be cooled by the upstream cooling air AR1 and the downstream cooling air AR2. Therefore, even in variant 1 of cooling structure S, the cooling performance can be improved.

In addition, in variant 1 of cooling structure S, although the housing becomes slightly larger to expand the flow path of the downstream cooling air AR2, the control unit 60 can be cooled from the opening 61D side of the case 61 by the downstream cooling air AR2. In other words, the control unit 60 can be cooled from both the top and bottom directions (thickness direction of the control unit 60) by the upstream cooling air AR1 and the downstream cooling air AR2. Therefore, the cooling performance for the control unit 60 can be effectively improved.

(Variation 2 of cooling structure S) Next, variation 2 of cooling structure S will be described using Figures 11 and 12. The cooling structure S of variation 2 is configured in the same manner as this embodiment, except for the points described below. That is, in the cooling structure S of variation 2, exhaust ports 23 are formed in the left and right side walls of the motor housing portion 16. Specifically, six exhaust ports 23 are formed in each of the upper and lower parts of the motor housing portion 16 so as to overlap with the rear end portion of the stator 43 of the motor 40 in a side view. Note that only the left side portion is shown, and in reality a similar exhaust port structure is also formed on the right side, so that a total of 12 exhaust ports 23 are formed in this embodiment.

Furthermore, inside the motor housing portion 16, a partition wall 25 is formed behind the exhaust port 23, and the partition wall 25 divides the space radially outside the motor 40 into front and rear. That is, in the second variant, the cooling air passage 70 is blocked by the partition wall 25.

In the second modification, the fan guide 17 is omitted except for the front fixing portion 17B, and a flow path changing portion 26 is formed between the motor 40 and the fan 72. The flow path changing portion 26 is configured such that the cross section opened to the rear side is formed in a substantially U-shaped plate shape (rib shape) in a side view. In addition, an insertion hole 26A penetrating in the front-rear direction is formed in the approximate center of the flow path changing portion 26, and the drive shaft 41 of the motor 40 is inserted through the insertion hole 26A. That is, the flow path changing portion 26 is a bowl-shaped part with an open bottom, and the rear edge portion is provided so as to abut or be close to the front end portion of the stator 43. Half of the flow path changing portion 26 is provided on one of the pair of split housings 15, and the other half is provided on the other, and is formed by assembling the split housings 15 together.

In variant 2, the upstream cooling air AR1 that flows into the motor housing portion 16 from the intake port 22 flows into the interior of the motor 40 from the radial inner side and radial outer side of the motor board 45, and flows forward inside the motor 40. Specifically, the upstream cooling air AR1 flows forward through the interior of the stator 43 and the portion between the rotor 42 and the stator 43. The upstream cooling air AR1 that has flowed through the interior of the motor 40 then hits the flow path change portion 26 and flows along the rear surface of the flow path change portion 26 toward the drive shaft 41. This causes the upstream cooling air AR1 to flow into the fan 72 from the insertion hole 26A.

Then, the upstream cooling air AR1 flowing into the fan 72 is discharged radially outward of the fan 72 as downstream cooling air AR2. At this time, the downstream cooling air AR2 flows toward the exhaust port 23. Therefore, the downstream cooling air AR2 flows rearward along the front surface of the flow path change section 26, and flows rearward above and below the motor 40. Then, the downstream cooling air AR2 that flows rearward above and below the motor 40 is exhausted from the exhaust port 23 to the outside of the motor housing section 16. As described above, in the second modification, the motor 40 (stator 43) can be cooled by the upstream cooling air AR1 and the downstream cooling air AR2. Therefore, in the second modification, the motor 40 corresponds to the cooled part of the present invention, and the cooling performance for the motor 40 can be improved.

Furthermore, in the second modification, the downstream cooling air AR2 flowing below the motor 40 flows between the motor 40 and the control unit 60, and is exhausted to the outside of the motor housing portion 16 through the exhaust port 23. Therefore, the control unit 60 and the motor 40 can be cooled by the downstream cooling air AR2.

In this embodiment, the cooling structure S is applied to the saber saw 10 to cool the control unit 60 and the motor 40 of the saber saw 10, but the cooling structure S may also be applied to other work machines. Below, examples in which the cooling structure S is applied to other work machines will be described as variations of the work machines.

(Working machine variation 1) Using Figure 13, we will explain an example in which the cooling structure S is applied to a circular saw 100 as a working machine. The circular saw 100 is a tool that performs cutting processing on a workpiece. Note that Figure 13 is a partially broken plan view of the circular saw 100 as viewed from above. The arrows FR and RH shown in Figure 13 indicate the front and right side of the circular saw 100.

Circular saw 100 includes a base 102 and a circular saw body 104. Base 102 is formed in a substantially rectangular plate shape with the plate thickness direction being the up-down direction. Circular saw body 104 is disposed on the upper side of base 102 and connected to base 102. Circular saw body 104 includes a housing 110 that forms the outer shell of circular saw body 104, a motor 120 disposed within housing 110, and a control unit 140 that controls motor 120. Circular saw body 104 also includes a circular saw blade (not shown), which is covered from above by a saw cover 152. The rotational force of motor 120 is transmitted to the circular saw blade, which rotates to perform cutting on the workpiece.

The housing 110 is configured to include a motor housing portion 111 that houses the motor 120, and a controller housing portion 112 that is disposed to the rear of the motor housing portion 111 and houses the control portion 140. The motor housing portion 111 and the controller housing portion 112 are formed in a concave shape that is open to the right side, and the left portion of the motor housing portion 111 and the left portion of the controller housing portion 112 are separated by a partition wall 113. A plurality of air intake ports 114 are formed through the front portion of the left wall of the controller housing portion 112, and a plurality of exhaust ports 115 are formed through the rear portion of the left wall of the controller housing portion 112.

The motor 120 is housed within the motor housing portion 111. The motor 120 includes a drive shaft 121 whose axial direction is in the left-right direction, a rotor 122 arranged radially outward of the drive shaft 121, and a stator 123 arranged radially outward of the rotor 122. A circular plate-shaped motor board 125 is provided to the right of the rotor 122 and the stator 123, and the motor board 125 is fixed to a stator holder 124 of the stator 123.

A fan 130 is provided on the right end of the drive shaft 121 to the right of the motor board 125 so as to be able to rotate integrally therewith, and the fan 130 is configured as a centrifugal fan. As a result, the downstream cooling air AR4 generated by the fan 130 flows rearward and into the right end of the controller housing part 112.

The control unit 140 is housed in the controller housing unit 112. The control unit 140 has a case 142 that forms the outer shell of the control unit 140. A control board (not shown) is housed in the case 142, and the motor 120 is connected to the control board. The case 142 is formed in a roughly box shape that is open to the front and has a thickness in the front-to-rear direction, and is fixed to the controller housing unit 112. Specifically, the right end of the case 142 is fixed to the fixed rib 112A of the controller housing unit 112, the bottom wall of the case 142 is fixed to the fixed rib 112B of the controller housing unit 112, and the left end of the case 142 is fixed to the fixed ribs 112C and 112D of the controller housing unit 112.

The case 142 extends in the left-right direction within the controller housing section 112. Specifically, the left end of the case 142 is disposed adjacent to the right side of the left wall of the controller housing section 112, and the right end of the case 142 is disposed spaced apart from the rear side of the fan 130. As a result, the inside of the controller housing section 112 is partitioned in the front-rear direction by the case 142 of the control section 140. The front space of the control section 140 in the controller housing section 112 is configured as the first space 116, and the first space 116 and the outside of the housing 110 are connected by the intake port 114. On the other hand, the rear space of the control section 140 in the controller housing section 112 is configured as the second space 117, and the second space 117 and the outside of the housing 110 are connected by the exhaust port 115. The right end of the second space 117 is open to the front side and disposed behind the fan 130.

When the circular saw 100 is in operation, the fan 130 rotates around the axis of the drive shaft 121 together with the drive shaft 121 of the motor 120. This causes the upstream cooling air AR3 to flow from the intake port 114 into the first space 116 of the controller housing section 112. The upstream cooling air AR3 that flows into the first space 116 flows to the right and hits the fixed rib 112A while cooling the opening side of the case 142 in the control section 140. The upstream cooling air AR3 that hits the fixed rib 112A flows to the front side (towards the fan 130). The upstream cooling air AR3 then flows along both sides of the motor board 125 in the plate thickness direction and flows into the fan 130 from the left side.

The upstream cooling air AR3 that flows into the fan 130 flows out to the rear from the fan 130 as downstream cooling air AR4, and the downstream cooling air AR4 flows into the right end of the second space 117 of the controller housing part 112. The downstream cooling air AR4 that flows into the right end of the second space 117 hits the rear wall of the controller housing part 112 and flows toward the exhaust port 115. In other words, the downstream cooling air AR4 flows to the left inside the second space 117 while cooling the bottom wall of the case 142 of the control unit 140. The downstream cooling air AR4 is then exhausted from the exhaust port 115 to the outside of the controller housing part 112.

As described above, in the circular saw 100, the rotation of the fan 130 generates upstream cooling air AR3 flowing into the fan 130 and downstream cooling air AR4 flowing out from the fan 130 within the housing 110, and the control unit 140 is cooled by the upstream cooling air AR3 (intake air) and downstream cooling air AR4 (exhaust air). Therefore, the cooling performance for the control unit 140 can be improved in the circular saw 100 as well. Although not shown, the downstream cooling air AR4 may contain air after cooling the motor 120.

Also, in the circular saw 100, the control unit 140 is cooled from both sides in the thickness direction by the upstream cooling air AR3 and the downstream cooling air AR4. This effectively improves the cooling performance for the control unit 140. In this embodiment, the opening side of the case 142 is positioned in the space through which the upstream cooling air AR3 passes. This is because the circular saw 100 is a tool primarily used to process wood, and the impact of wood workpieces on electronic elements, etc. is smaller than that of metal, and because it takes into consideration that the electronic elements exposed from the case 142 are directly exposed to the upstream cooling air AR3 and cooled preferentially.

(Working machine variation 2) Using Figure 14, an example in which the cooling structure S is applied to a hammer drill 200 as a working machine will be described. The hammer drill 200 is a tool that performs processes such as drilling holes in a workpiece. Figure 14 is a cross-sectional view of the hammer drill 200 as viewed from the right side. The arrows UP and FR shown in Figure 14 indicate the upper side and front side of the hammer drill 200.

The hammer drill 200 includes a housing 210 that forms the outer shell of the hammer drill 200, a motor 220 housed in the housing 210, a drive mechanism 250 that is driven by the driving force of the motor 220 and has a tool tip attached thereto, and a control unit 240 that controls the motor 220. When the motor 220 is driven, the driving force transmitted from the motor 220 to the drive mechanism 250 applies a rotational force and an impact force from the tool tip to the workpiece.

The housing 210 is hollow and formed in a generally horizontal P-shape. The housing 210 includes a motor housing section 211 that constitutes the front end of the lower part of the housing 210, and a controller housing section 212 that is disposed to the rear of the motor housing section 211, and a partition wall 213 separates the lower part of the motor housing section 211 from the lower part of the controller housing section 212.

A plurality of air intake ports 214 are formed through the front portion of the lower wall of the controller housing portion 212, and a plurality of exhaust ports 215 are formed through the rear portion of the lower wall of the controller housing portion 212.

The motor 220 includes a drive shaft 221 whose axial direction is the up-down direction, a rotor 222 arranged radially outward of the drive shaft 221, and a stator 223 arranged radially outward of the rotor 222. A motor board 225 having an annular plate shape is provided above the rotor 222 and the stator 223, and the motor board 225 is fixed to a stator holder 224 of the stator 223.

A fan 230 is provided on the upper end of the drive shaft 221, above the motor board 225, so as to be able to rotate integrally with the drive shaft 221. The fan 230 is configured as a centrifugal fan. This allows the downstream cooling air AR6 generated by the fan 230 to flow rearward from the fan 230 and into the upper end of the controller housing part 212.

The control unit 240 is housed within the controller housing section 212. The control unit 240 has a case 242 that forms the outer shell of the control unit 240. A control board (not shown) is housed in the case 242, and the motor 220 is connected to the control board. The case 242 is formed in a roughly box-like shape with its thickness extending in the front-to-rear direction and open to the rear, and is fixed to the controller housing section 212.

The case 242 extends vertically within the controller housing section 212. Specifically, the lower end of the case 242 is disposed adjacent to the upper side of the lower wall of the controller housing section 212, and the upper end of the case 242 protrudes upward beyond the partition wall 213. As a result, the interior of the controller housing section 212 is partitioned in the front-rear direction by the case 242 of the control section 240. The front space of the control section 240 in the controller housing section 212 is configured as a first space 216, and the first space 216 and the outside of the controller housing section 212 are connected by an air intake 214. On the other hand, the rear space of the control section 240 in the controller housing section 212 is configured as a second space 217, and the second space 217 and the outside of the controller housing section 212 are connected by an air exhaust 215.

When the hammer drill 200 is in operation, the fan 230 rotates around the axis of the drive shaft 221 together with the drive shaft 221 of the motor 220. This causes the upstream cooling air AR5 to flow from the intake port 214 into the first space 216 of the controller housing section 212. The upstream cooling air AR5 that has flowed into the first space 216 flows upward while cooling the bottom wall of the case 242 of the control section 240, and is then flowed into the motor housing section 211 from the upper side of the partition wall 213. The upstream cooling air AR5 that has flowed into the motor housing section 211 flows upward between the motor board 225 and the drive shaft 221, and is then flowed into the fan 230.

The upstream cooling air AR5 that flows into the fan 230 flows out rearward from the fan 230 as downstream cooling air AR6, and the downstream cooling air AR6 flows into the upper end of the second space 217 of the controller housing section 212. The downstream cooling air AR6 that flows into the upper end of the second space 217 hits the rear wall of the controller housing section 212 and flows downward within the second space 217 while cooling the control section 240 from the opening side of the case 242. The downstream cooling air AR6 is then exhausted from the exhaust port 215 to the outside of the controller housing section 212.

As described above, in the hammer drill 200, the rotation of the fan 230 generates upstream cooling air AR5 flowing into the fan 230 and downstream cooling air AR6 flowing out from the fan 230 within the housing 210, and the control unit 240 is cooled by the upstream cooling air AR5 and downstream cooling air AR6. Therefore, in the hammer drill 200, the cooling performance for the control unit 240 can be improved.

Also, in the hammer drill 200, the control unit 240 is cooled from both sides in the thickness direction by the upstream cooling air AR5 and the downstream cooling air AR6. This makes it possible to effectively improve the cooling performance for the control unit 240.

10...Saber saw (working machine), 12...Housing, 15...Divided housing, 16A...First space, 16B...Second space, 17...Fan guide (flow straightening section), 17A...Guide hole, 17D...Exposure hole (exposure section), 21...Clamping section, 22...Air intake, 23...Air exhaust, 40...Motor, 60...Control section (cooled section), 61...Case, 61A...Bottom wall, 61D...Opening, 62...Control board, 72...Fan, 100...Circular saw (working machine), 110...Housing, 114...Air intake, 115...Air exhaust, 116...First space, 1 Reference Signs List 17...second space, 120...motor, 130...fan, 140...control section (cooled section), 142...case, 200...hammer drill (working machine), 210...housing, 214...intake port, 215...exhaust port, 216...first space, 217...second space, 220...motor, 230...fan, 240...control section (cooled section), 242...case, AR...cooling air, AR1...upstream cooling air, AR2...downstream cooling air, AR3...upstream cooling air, AR4...downstream cooling air, AR5...upstream cooling air, AR6...downstream cooling air

Claims (10)

a housing having an intake port and an exhaust port;
A motor accommodated in the housing;
a fan that is accommodated in the housing and rotates when driven by the motor to generate cooling air inside the housing;
a control unit that controls the motor and is cooled by the cooling air;
Equipped with
the control unit is accommodated in the housing so as to be located to the side of the motor and defines a space in which the motor is accommodated;
the cooling air includes upstream cooling air that is sucked into the housing through the intake port and flows into the fan, and downstream cooling air that flows out of the fan and is exhausted to the outside of the housing through the exhaust port,
The control unit is a work machine cooled by the upstream cooling air and the downstream cooling air. The housing includes:
a first space through which the upstream cooling air passes and a second space through which the downstream cooling air passes,
The work machine according to claim 1 , wherein the control unit is exposed to the first space and the second space. The housing is composed of a plurality of divided housings,
3. The work machine according to claim 2, wherein the split housing is formed with a clamping portion for clamping the control portion. the housing is provided with a straightening portion that divides the first space and the second space and straightens the upstream cooling air and guides it to the second space,
The work machine according to claim 2 or 3, wherein the airflow rectifying portion is formed with an exposed portion for exposing a part of the control portion to the second space. The fan is disposed in the second space,
The work machine according to claim 4 , wherein the straightening portion has a guide hole that connects the first space and the second space, and the fan and the guide hole are arranged opposite each other in the axial direction of the fan. The control unit is
A control board connected to the motor;
a box-shaped case that houses the control board and has one opening in a thickness direction;
It is composed of
3. The work machine according to claim 2, wherein the cooling air cools a bottom wall of the case. The control unit is disposed in the first space,
7. The work machine according to claim 6, wherein the air intake is disposed on the other side of the bottom wall of the case in the thickness direction of the case. The work machine according to claim 6, wherein the control unit separates the first space from the second space. The work machine according to claim 8, wherein the bottom wall of the case is exposed to the first space, and the opening of the case is open toward the second space. A part of the control unit is disposed radially outward of the fan,
The work machine according to any one of claims 1 to 9, wherein the fan is configured as a centrifugal fan.

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