Portable processing machine

Abstract

To suppress noise and / or accumulation of dust in a portable processing machine accompanied with eccentric motion.SOLUTION: A portable processing machine is equipped with a motor, an output shaft that extends in an axis direction and can be rotated by rotation driving force of a motor, a tool accessory that is configured to eccentrically move with rotations of the output shaft, a dust collection fan that is fixed to the output shaft so as to surround the output shaft in a circumferential direction, and a balancer that is attached to at least one of the dust collection fan and a motor cooling fan. At a position where the balancer is attached in a circumferential direction of at least one fan and between an edge portion on the opposite side to the balancer in axis direction and the balancer of at least one of the fans, a channel is formed so as to discharge air flowing in the axis direction to diametrically outside toward at least one of the fans.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a portable processing machine. [Background technology]

[0002] Orbital sanders have been known as portable processing machines. In an orbital sander, a pad connected to one end of an output shaft (e.g., a motor shaft) moves in an eccentric circular motion (orbital motion). Sanding paper is attached to the pad. Sanding work can be performed by pressing the sanding paper against the workpiece.

[0003] In such an orbital sander, vibration occurs due to the eccentric circular motion of the pad. The following Patent Document 1 discloses a technique for reducing the occurrence of such vibration by attaching a balancer to a part of the circumferential direction of a fan (a fan in which a dust collection fan and a motor cooling fan are integrated) fixed around the output shaft, thereby eliminating static unbalance and couple unbalance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 9,545,712 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the sander described in Patent Document 1 leaves room for improvement. For example, in the area where the fan's circumferential blades are arranged, the air flowing along the output shaft hits the main plate of the fan and is guided radially outward by the blades. In the case of a dust-collecting fan, the air guided radially outward enters and flows through a flow path in the housing and is guided to a dust-collecting bag, and in the case of a motor cooling fan, it is guided to an exhaust port formed in the housing. On the other hand, in the area where the fan's circumferential balancer is arranged, the air flowing along the output shaft cannot flow radially outward due to the balancer acting as a barrier. This means that there are periods in which the introduction of air into the flow path or exhaust port in the housing is smooth and periods in which it is inhibited, depending on the rotational position of the fan. Such a phenomenon leads to a sudden fluctuation in air pressure, and noise caused by the fluctuation may become a problem. Alternatively, in the area where the fan's circumferential balancer is arranged, air cannot flow radially outward, so dust is likely to accumulate in the small gap between the balancer and the fan.

[0006] Such problems are not limited to orbital sanders, but are common to various portable processing machines with eccentric circular motion. For this reason, it is expected that noise generation and / or dust accumulation will be suppressed in portable processing machines with eccentric motion. [Means for solving the problem]

[0007] This specification discloses a portable processing machine. The portable processing machine may include a motor, an output shaft extending in an axial direction and rotatable by a rotational driving force of the motor, a tool accessory configured to perform an eccentric circular motion with the rotation of the output shaft, a dust collection fan fixed to the output shaft so as to surround the output shaft in a circumferential direction, a motor cooling fan configured to rotate by the rotational driving force of the motor, and a balancer attached to at least one of the dust collection fan and the motor cooling fan. A flow path may be formed at a position in the circumferential direction of the at least one fan where the balancer is attached, between an edge of the at least one fan opposite to the balancer in the axial direction and the balancer, so as to discharge air flowing in the axial direction toward the at least one fan to the radially outward side.

[0008] According to the above configuration, even in the region where the circumferential balancer of at least one of the fans is arranged, the air flowing along the output shaft can be guided radially outward through a flow passage between the balancer and an edge of at least one of the fans on the opposite side of the balancer in the axial direction. Therefore, the fluctuation in air pressure caused by the rotation of at least one of the fans is mitigated. As a result, the generation of noise is suppressed. Moreover, the flow passage guides dust radially outward together with the air, so that the accumulation of dust in the gap between the balancer and at least one of the fans can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a sander according to one embodiment. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. 3 is a partially enlarged cross-sectional view taken along line AA in FIG. 2. [Diagram 5] FIG. 3 is a partially enlarged cross-sectional view taken along line AA in FIG. 2. [Figure 6] FIG. 2 is a perspective view of the fan as viewed from the dust collection fan side. [Figure 7] FIG. 2 is a perspective view of the fan as viewed from the motor cooling fan side. [Figure 8] FIG. [Figure 9] FIG. 1 is a bottom view of the dust collection fan, with the structure on the opposite side of the balancer shown in dotted lines. [Figure 10] FIG. [Figure 11] FIG. 2 is a perspective view of a balancer for a dust collection fan. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Representative and non-limiting examples of the present invention will now be described in detail with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing preferred examples of the present invention, and is not intended to limit the scope of the present invention. In addition, the additional features and inventions disclosed below can be used separately or together with other features and inventions to provide further improved devices, methods of making and using the same.

[0011] Furthermore, the combinations of features and steps disclosed in the following detailed description are not essential to the practice of the invention in its broadest sense, but are specifically described only to illustrate representative embodiments of the invention. Furthermore, the various features of the representative embodiments described above and below, and the various features of those described in the independent and dependent claims, do not have to be combined in the exact embodiments described herein, or in the exact order listed, to provide additional and useful embodiments of the invention.

[0012] All features described in the specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the original disclosure and claimed particulars, apart from any configuration of the features described in the embodiments and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose their intermediate configurations as limitations to the original disclosure and claimed particulars.

[0013] In one or more embodiments, at least one of the fans may include a main plate and a plurality of blades extending at least partially in a substantially radial manner on one surface of the main plate. The one surface may be a surface on the side where the balancer is located with respect to the main plate. The flow passage may be formed between the one surface of the main plate and the balancer. With this configuration, a flow passage for discharging air flowing along the output shaft radially outward can be formed with a simple configuration. "Extending at least partially in a substantially radial manner" means extending substantially radially at at least a part of an angular position in the circumferential direction. "Substantially" radially means that the extension direction of the plurality of blades may be angled with respect to a strict radial direction.

[0014] In one or more embodiments, one of the main plate and the balancer may have a protrusion extending toward and abutting the other. A gap that functions as a flow path may be formed between the main plate and the balancer by the protrusion. With this configuration, a flow path that discharges air flowing along the output shaft radially outward can be formed with a simpler configuration.

[0015] In one or more embodiments, the protrusions may have a shape that functions as a straightening portion that directs the air flow in the flow passage radially outward. This configuration promotes the air flow in the flow passage radially outward. Therefore, noise generation and dust accumulation can be further suppressed.

[0016] In one or more embodiments, each of the plurality of vanes may extend at least partially radially, crossing the radial direction. The protrusions may be arranged crossing the radial direction in the same direction as the plurality of vanes. This configuration further promotes radially outward airflow in the flow passage. Therefore, noise generation and dust accumulation can be further suppressed.

[0017] In one or more embodiments, the balancer may include a protrusion. With this configuration, the weight of the balancer is greater than in a configuration in which the main plate of at least one of the fans includes a protrusion. Therefore, the installation area of ​​the balancer on a horizontal plane perpendicular to the axial direction can be made compact.

[0018] In one or more embodiments, the dust collection fan and the motor cooling fan may be in the form of an integrated single fan including a main plate having a first surface and a second surface opposite to the first surface, a plurality of first blades extending at least partially radially on the first surface, and a plurality of second blades extending at least partially radially on the second surface. This configuration can reduce the number of parts and the number of assembly steps of the portable processing machine.

[0019] In one or more embodiments, the balancer may be made of metal. At least one of the fans may have a lower specific gravity than the balancer. With this configuration, the weight difference between at least one of the fans and the balancer can be increased, so static imbalance and couple imbalance can be efficiently eliminated. Alternatively, the required weight difference can be ensured with a relatively small balancer capacity, so the balancer can be made compact.

[0020] In one or more embodiments, at least one of the fans may have a screw boss protruding toward the balancer. The balancer may have a through hole formed at a position corresponding to the screw boss. The protrusion may protrude toward the at least one of the fans around the through hole and have a shape and size that allows the outer periphery of the screw boss to fit into it. The at least one of the fans and the balancer may be fixed to each other by a screw member inserted into the through hole and the screw boss. With this configuration, a flow path that discharges air radially outward can be formed with a simple configuration, and the balancer can be accurately and easily positioned relative to the at least one of the fans. In other words, the protrusion can perform two functions.

[0021] The sander 10 as an exemplary embodiment will be described in more detail below with reference to the drawings. The sander 10 is also referred to as a random orbit sander.

[0022] 4 and 5, the sander 10 includes an electric motor 60, a motor shaft 61, and a tool accessory 40. One end of the motor shaft 61 is connected to the tool accessory 40 via another member. As will be described in detail later, the sander 10 is configured such that the tool accessory 40 performs a sanding motion by the rotation of the electric motor 60 (motor shaft 61).

[0023] In the following description, the direction in which the motor shaft 61 extends is defined as the up-down direction of the sander 10. In the up-down direction, the side where the tool accessory 40 is located is defined as the lower side, and the opposite side is defined as the upper side. In addition, the longitudinal direction of the sander 10 perpendicular to the up-down direction is defined as the front-rear direction of the sander 10. In the front-rear direction, the side where the tool accessory 40 is located is defined as the front side, and the opposite side is defined as the rear side. In addition, the direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction of the sander 10. In the left-right direction, the right side when viewed from the rear side to the front side is defined as the right side of the sander 10, and the opposite side is defined as the left side of the sander 10.

[0024] As shown in Figures 1 to 3, the sander 10 includes a housing 20. The housing 20 includes a front housing portion 21, a grip portion 22, and a rear housing portion 23. The front housing portion 21 and the rear housing portion 23 are connected in the front-rear direction by a bifurcated shape spaced apart from each other vertically, and the upper connecting portion functions as the grip portion 22. A power cord 26 for supplying power to the electric motor 60 extends from the rear end of the rear housing portion 23.

[0025] As shown in Fig. 4, a controller 65 is accommodated in the lower part of the rear housing part 23. The controller 65 is electrically connected to the power cord 26 and the electric motor 60, and controls the operation of the electric motor 60 by controlling the power supplied to the electric motor 60. As shown in Fig. 1, a switch button 27 is provided in the front part of the front housing part 21 for performing an operation for starting and stopping the electric motor 60. A switch unit 48 is arranged behind the switch button 27 so as to be able to cooperate with it. The switch unit 48 is electrically connected to the controller 65.

[0026] 4 and 5, an electric motor 60 is housed in the front housing portion 21. A motor shaft 61 of the electric motor 60 extends in the vertical direction and is rotatably supported by bearings 62 and 63 fixed to the front housing portion 21. The bearing 62 supports the upper end of the motor shaft 61, and the bearing 63 supports the motor shaft 61 near its lower end.

[0027] A fan 70 is disposed below the bearing 63. The fan 70 is fixed to the motor shaft 61 so as to surround the motor shaft 61 in the circumferential direction. In this embodiment, the fan 70 has both a function as a motor cooling fan and a function as a dust collection fan. Specifically, an upper portion of the fan 70 functions as a motor cooling fan, and a lower portion of the fan 70 functions as a dust collection fan. For this reason, in the following description, the upper portion of the fan 70 is also referred to as a motor cooling fan 100, and the lower portion of the fan 70 is also referred to as a dust collection fan 200.

[0028] As shown in FIG. 6 and FIG. 7, the fan 70 includes a disk-shaped main plate 71. A shaft insertion hole 76 is formed in the center of the main plate 71, penetrating the fan 70 in the vertical direction. The motor shaft 61 is inserted into the shaft insertion hole 76. The main plate 71 includes an upper portion 73 having a first surface 72 facing upward, and a lower portion 75 having a second surface 74 facing downward. The upper portion 73, which functions as a part of the motor cooling fan 100, is also called the main plate 110. The lower portion 75, which functions as a part of the dust collection fan 200, is also called the main plate 210. In this embodiment, the upper portion 73 and the lower portion 75 are one part integrally formed without using secondary adhesion or mechanical joining, but may be bonded or mechanically joined by any method. In this embodiment, the radius of the lower portion 75 is slightly larger than the radius of the upper portion 73. A rib extending horizontally from the inner surface of the front housing portion 21 is disposed in the step formed thereby, thereby restricting air flow between the spaces above and below the main plate 71.

[0029] 7, a plurality of first blades 120 extend partially (in other words, at predetermined angular positions) in a substantially radial manner on the main plate 110 (first surface 72) of the motor cooling fan 100. In this embodiment, the extension direction of the first blades 120 is angled with respect to the radial direction.

[0030] When the fan 70 (motor cooling fan 100) rotates with the rotation of the motor shaft 61, air flows from the outside to the inside of the housing 20 through the intake port 24 (see Figs. 1 and 3) formed in the grip portion 22. This air flows in the axial direction (the direction in which the motor shaft 61 extends) through the electric motor 60 and reaches the motor cooling fan 100. In the motor cooling fan 100, the air flowing downward collides with the main plate 110 and is directed radially outward by the action of the first blades 120, and is then discharged to the outside of the housing 20 through the exhaust port 25 (see Figs. 1 and 3) formed in the front housing portion 21. This air flow cools the electric motor 60. The exhaust port 25 is formed at a position corresponding to the motor cooling fan 100 in the vertical direction.

[0031] As shown in Fig. 6, the dust collection fan 200 includes a shaft portion 230. The shaft portion 230 protrudes cylindrically downward from the main plate 210 near the center of the main plate 210. A shaft insertion hole 76 is formed inside the shaft portion 230. On the main plate 210 (second surface 74) of the dust collection fan 200, a plurality of second blades 220 extend radially partially (in other words, at a predetermined angular position) radially outward from the shaft portion 230. In this embodiment, the extension direction of the second blades 220 is angled with respect to the radial direction.

[0032] As shown in FIG. 5, the shaft portion 230 is rotatably supported by the bearing 64. The motor shaft 61 has a screw hole 66 extending upward from its lower end. With the lower end of the motor shaft 61 inserted into the shaft insertion hole 76, the plate 67 is disposed below the shaft portion 230. At this time, the plate 67 abuts against the lower end of the bearing 64. The plate 67 has a through hole formed at a position corresponding to the screw hole 66. By inserting a bolt 68 into the through hole and the screw hole 66 from below and tightening it, the inner ring of the bearing 64 and the inner ring of the bearing 63 sandwich the fan 70 in the vertical direction. This fixes the positional relationship between the motor shaft 61, the fan 70, the bearing 63, and the bearing 64.

[0033] 5, in this mounted state, the shaft portion 230 of the dust-collection fan 200 is eccentric with respect to the motor shaft 61. Therefore, the bearing 64 is eccentric with respect to the motor shaft 61.

[0034] As shown in Figs. 4 and 5, the accommodation space 28 of the dust collection fan 200 in the front housing portion 21 communicates with a dust collection passage 29 extending in the front-rear direction through the lower part of the rear housing portion 23. The accommodation space 28 and the dust collection passage 29 are connected via an inlet 29a located at the rearmost part of the accommodation space 28. As shown in Fig. 4, the dust collection passage 29 communicates with the dust collection nozzle 30. The dust collection nozzle 30 extends cylindrically from the lower and rear edge of the rear housing portion 23 toward the rear. As shown in Figs. 1 and 4, a dust bag 31 is removably attached to the dust collection nozzle 30.

[0035] As shown in Figs. 1 to 3, the tool accessory 40 is located at the bottom of the sander 10 and includes a pad 41. The pad 41 has a circular shape when viewed in the vertical direction. The pad 41 includes a flat surface 42 for attaching sanding paper (not shown). The flat surface 42 is the bottom surface of the pad 41 and extends in the horizontal direction (the direction perpendicular to the vertical direction). As shown in Fig. 5, the pad 41 is connected by a bolt 43 to a bearing box 69 that supports a bearing 64.

[0036] As shown in Figs. 4 and 5, a plurality of holes 44 extending upward are formed in the bottom surface of the pad 41. The plurality of holes 44 communicate with a space 45 that spreads in the horizontal direction at the top of the pad 41. This space 45 communicates with a communication hole 46 formed in the top surface of the pad 41. The communication hole 46 opens toward an opening in the bottom surface of the front housing part 21. The opening in the bottom surface of the front housing part 21 communicates with the accommodation space 28 that accommodates the dust collection fan 200. Sanding paper (not shown) is attached to the bottom surface of the pad 41. This sanding paper has holes formed in positions corresponding to the holes 44 of the pad 41.

[0037] When the fan 70 (dust collection fan 200) rotates with the rotation of the motor shaft 61, air containing dust flows into the accommodation space 28 through the holes in the sanding paper, the holes 44, the space 45, and the communication hole 46. At this time, the air collides with the main plate 210 of the dust collection fan 200 and is guided radially outward by the action of the second blade 220 of the dust collection fan 200. The air thus directed enters the dust collection passage 29 from the inlet 29a and flows into the dust bag 31 through the dust collection nozzle 30. This air flow allows the dust generated during the sanding work to be collected in the dust bag 31.

[0038] The sander 10 described above operates as follows. First, when a user operates the switch button 27 to drive the electric motor 60, the motor shaft 61 starts to rotate. The rotation of the motor shaft 61 is transmitted to a bearing box 69 supporting the bearing 64 via a bearing 64 that is eccentric with respect to the motor shaft 61. As a result, the bearing box 69 and the tool accessory 40 connected to the bearing box 69 perform eccentric circular motion and rotational motion. In this state, sanding is performed by pressing the sanding paper attached to the flat surface 42 of the pad 41 against the workpiece.

[0039] Such eccentric circular motion of the tool accessory 40 causes vibration. For this reason, the sander 10 is provided with a configuration for eliminating static unbalance and couple unbalance by mounting a balancer 140 and a balancer 240 to the motor cooling fan 100 and the dust collection fan 200, respectively, to reduce the generation of vibration. Such a configuration will be described below.

[0040] As shown in FIG. 7, the balancer 140 is attached to a portion of the motor cooling fan 100 in the circumferential direction (a region where the first blades 120 are not formed). Specifically, the main plate 71 is formed with a screw boss 150. As shown in FIG. 5, the screw boss 150 protrudes upward and downward on both the motor cooling fan 100 side and the dust collection fan 200 side. The bolt 160 is inserted from above into the screw boss 150 so as to pass through the through hole of the balancer 140, and is tightened, thereby fixing the balancer 140 to the motor cooling fan 100 as shown in FIG. 7. As shown in FIG. 5, the balancer 140 has a recess that fits into the portion of the screw boss 150 that protrudes upward. This makes it easy to position the balancer 140 relative to the main plate 110. When the balancer 140 is attached to the motor cooling fan 100, as shown in FIG. 7, no gap is formed between the balancer 140 and the first surface 72 of the main plate 110.

[0041] As shown in Fig. 6, the balancer 240 is attached to a portion of the dust collection fan 200 in the circumferential direction (an area where the second blades 220 are not formed). Specifically, a screw boss 250 is formed on the main plate 71. As shown in Figs. 7 and 10, the screw boss 250 protrudes downward and upward on both the dust collection fan 200 side and the motor cooling fan 100 side, respectively. The screw boss 250 protruding downward on the dust collection fan 200 side is also called a screw boss 251 (see Fig. 10). The screw boss 250 protruding upward on the motor cooling fan 100 side is also called a screw boss 252 (see Fig. 7).

[0042] As shown in FIG. 11, the balancer 240 has two through holes 265. The through holes 265 are formed at positions corresponding to the two screw bosses 251 of the dust collection fan 200. The balancer 240 further has, on its upper surface, protrusions 261, 262 that protrude upward (towards the dust collection fan 200). The protrusion 261 extends in an elongated manner in a substantially radial direction. The protrusion 262 has a fitting protrusion 263 and a flow straightening protrusion 264. The fitting protrusion 263 is formed in an annular shape so as to surround the periphery of the through hole 265, and has a shape and size in which the outer periphery of the screw boss 251 of the dust collection fan 200 fits into it. The flow straightening protrusion 264 extends in a substantially radial direction from the fitting protrusion 263.

[0043] To attach the balancer 240 to the dust collection fan 200, first, the balancer 240 is positioned so that the screw boss 251 of the dust collection fan 200 fits inside the fitting protrusion 263. This method makes it possible to quickly and easily position the balancer 240 relative to the dust collection fan 200. Then, the bolt 260 is inserted from below into the screw boss 251 so as to pass through the through hole 265 of the balancer 240, and is tightened, thereby fixing the balancer 240 to the dust collection fan 200 as shown in FIG.

[0044] At this time, the upper surfaces of the protrusions 261, 262 come into contact with the second surface 74 of the main plate 210 of the dust-collection fan 200. As a result, as shown in FIG. 6, a gap 270 is formed between the balancer 240 and the main plate 210. This gap 270 functions as a flow path when air flows through the above-mentioned route for dust collection. That is, in the circumferential region in which the balancer 240 is arranged, the air flows into the accommodation space 28 from the hole 44 of the pad 41, and the air that collides with the main plate 210 is discharged radially outward through the gap 270. For this reason, the gap 270 is also called the flow path 270.

[0045] According to this configuration, even when the motor shaft 61 (and thus the dust collection fan 200 and the balancer 240) rotates and the balancer 240 is in a position radially opposite to the inlet 29a of the dust collection passage 29, the air that flows into the accommodation space 28 from the hole 44 of the pad 41 and collides with the main plate 210 is discharged radially outward through the flow path 270. Therefore, compared to a configuration in which the flow path 270 is not formed, the pressure fluctuation of the air near the inlet 29a between when the second blade 220 of the dust collection fan 200 is in a position opposite to the inlet 29a and when the balancer 240 is in a position opposite to the inlet 29a is mitigated. As a result, the generation of noise is suppressed. Moreover, the flow path 270 guides dust radially outward together with the air, so that the accumulation of dust in the gap between the balancer 240 and the dust collection fan 200 can be suppressed.

[0046] Moreover, according to the above-mentioned configuration, the flow path 270 can be formed with a simple configuration by utilizing the convex portions 261, 262 of the balancer 240. However, the flow path 270 between the balancer 240 and the dust collection fan 200 can be formed by any method. For example, a spacer may be disposed between the balancer 240 and the dust collection fan 200.

[0047] Furthermore, the protrusion 261 extends in a substantially radial direction, and the flow straightening protrusion 264 also extends in a radial range similar to that of the protrusion 261 in cooperation with a part of the fitting protrusion 263. Therefore, 261 and 262 also function as flow straightening parts that direct the air flow in the flow path 270 radially outward. Therefore, the air flow toward the radially outward direction in the flow path 270 is promoted, and the generation of noise and the accumulation of dust can be further suppressed. Moreover, as shown in FIG. 9, the protrusions 261 and 262 that function as flow straightening parts are arranged so as to cross the radial direction in the same direction as the second blade 220 of the dust collection fan 200. Therefore, the air flow toward the radially outward direction in the flow path 270 is further promoted.

[0048] Furthermore, with the above configuration, the motor cooling fan 100 and the dust collection fan 200 are integrally formed, which reduces the number of parts and the number of assembly steps of the sander 10. However, the motor cooling fan 100 and the dust collection fan 200 may be separate bodies. In this case, the motor cooling fan 100 and the dust collection fan 200 may be disposed adjacent to each other or spaced apart in the axial direction.

[0049] Furthermore, according to the above configuration, since the convex portions 261, 262 are formed on the balancer 240, the weight of the balancer 240 can be increased by the weight of the convex portions 261, 262 without changing the horizontal area of ​​the balancer 240. Therefore, the weight required to generate the centrifugal force required to eliminate static imbalance and couple imbalance can be achieved with a compact horizontal area of ​​the balancer 240. However, instead of the balancer 240, convex portions having the same function as the convex portions 261, 262 (convex portions protruding from the main plate 210 toward the balancer 240) may be formed on the main plate 210 of the dust collection fan 200.

[0050] In the above-described embodiment, the fan 70 and the balancer 140, 240 may be made of any material. For example, the balancer 140, 240 may be made of a metal (e.g., a heavy metal (e.g., iron, zinc, copper, an alloy containing any of them (e.g., brass) or the like)). The fan 70 may be made of a material having a smaller specific gravity than the material of the balancer 140, 240 (e.g., a synthetic resin, a light metal (e.g., aluminum, magnesium, titanium, an alloy containing any of them, or the like)). In this way, the weight difference between the fan 70 and the balancer 140, 240 can be increased, so that static unbalance and couple unbalance can be efficiently eliminated. Alternatively, the necessary weight difference can be ensured with a relatively small capacity of the balancer 140, 240, so that the balancer 140, 240 can be made compact.

[0051] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is for facilitating understanding of the present invention and does not limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. In addition, any combination or omission of each element described in the claims and specification is possible within the scope of solving at least a part of the above-mentioned problems or achieving at least a part of the effects.

[0052] For example, instead of the flow path 270 formed between the main plate 210 of the dust collecting fan 200 and the balancer 240, a flow path of any shape that discharges air radially outward may be formed at a position where the balancer 240 is attached in the circumferential direction of the dust collecting fan 200, between the edge of the dust collecting fan 200 opposite the balancer 240 in the up-down direction (i.e., the upper edge) and the balancer 240. For example, a recess extending in a substantially radial direction may be formed in the main plate 210 of the dust collection fan 200, the balancer 240 may be disposed on the recess, and the inside of the recess may function as a flow path. Alternatively, when the main plate 210 has a sufficient thickness, a recess may be formed in a region of the main plate 210 that is radially inward from the balancer 240 at the circumferential position where the balancer 240 is disposed, and a side hole may be formed in the substantially radial direction from the side surface of the recess, opening at the side surface of the main plate 210. Such a side hole can also fulfill the same function as the flow path 270 described above.

[0053] Furthermore, in the case where the motor cooling fan 100 and the dust collection fan 200 are arranged coaxially as in the above-described embodiment, the motor cooling fan 100 may have a configuration similar to that of the dust collection fan 200 (various configurations related to the flow path 270) instead of or in addition to the dust collection fan 200. Also, in the case where a spindle (output shaft) interlocked with the motor shaft is arranged parallel to the motor shaft, a motor cooling fan is attached to the motor shaft, and a dust collection fan is attached to the spindle, the dust collection fan may have a configuration similar to that of the dust collection fan 200.

[0054] Furthermore, the above-described embodiment is not limited to a random orbit sander, but can be applied to various portable processing machines that involve eccentric circular motion. For example, the above-described embodiment can be applied to an orbital sander, a polisher, etc.

[0055] The correspondence between each component of the above embodiment and each component of the present invention is shown below. However, each component of the embodiment is merely an example and does not limit each component of the present invention. The sander 10 is an example of a "portable processing machine". The electric motor 60 is an example of a "motor". The motor shaft 61 is an example of an "output shaft". The tool accessory 40 is an example of a "tool accessory". The motor cooling fan 100 is an example of a "motor cooling fan". The dust collection fan 200 is an example of a "dust collection fan". The balancer 240 is an example of a "balancer". The flow path 270 is an example of a "flow path". The main plate 210 is an example of a "main plate". The second blade 220 is an example of a "plurality of blades" and a "plurality of second blades". The convex portions 261 and 262 are examples of a "protruding portion". The first blade 120 is an example of a "first blade". The second blade 220 is an example of a "second blade". First surface 72 is an example of a "first surface." Second surface 74 is an example of a "second surface." Screw boss 251 is an example of a "screw boss." Through hole 265 is an example of a "through hole." Bolt 260 is an example of a "screw member." [Explanation of symbols]

[0056] 10... Sanda 20...Housing 21...Front housing part 22...Grip section 23...Rear housing section 24...Intake port 25...Exhaust port 26...Power cord 27...Switch button 28...Containment space 29...Dust collection passage 29a...Entrance 30...Dust collection nozzle 31...Dust bag 40...Tool accessories 41...Pad 42...Flat surface 43...Bolts 44...hole 45...Space 46...Communication hole 48...Switch unit 60...Electric motor 61...Motor shaft 62,63,64...Bearings 65...Controller 66...Screw hole 67...Plate 68...Volts 69...Bearing box 70...Fan 71...Main plate 72...First Side 73...upper part 74...Second Side 75...lower part 76...Shaft insertion hole 100...Motor cooling fan 110...main plate 120...First Feather 140...Balancer 150...Screw boss 160...Volts 200...Dust collection fan 210...main plate 220...Second Feather 230...shaft 240...Balancer 250, 251, 252...Screw boss 260...Volts 261,262...Convex 263...Mating protrusion 264...Straightening protrusion 265...Through hole 270...flow path (gap)

Claims

1. A portable processing machine, A motor; an output shaft extending in an axial direction and rotatable by a rotational driving force of the motor; a tool accessory configured to undergo eccentric circular motion with rotation of the output shaft; a dust collection fan fixed to the output shaft so as to surround the output shaft in a circumferential direction; a motor cooling fan configured to rotate by the rotational driving force of the motor; a balancer attached to at least one of the dust collection fan and the motor cooling fan; Equipped with A flow passage is formed at a position in the circumferential direction of the at least one fan where the balancer is attached, between an edge portion of the at least one fan opposite to the balancer in the axial direction and the balancer, so as to discharge air flowing in the axial direction toward the at least one fan outward in the radial direction. Portable processing machine.

2. 2. The portable processing machine according to claim 1, The at least one fan includes a main board and a plurality of blades extending generally radially at least partially on one surface of the main board; the one surface is a surface on a side of the main plate on which the balancer is located, The flow path is formed between the one surface of the main plate and the balancer. Portable processing machine.

3. 3. The portable processing machine according to claim 2, One of the main plate and the balancer includes a protrusion extending toward the other and abutting against the other, The gap functioning as the flow path is formed between the main plate and the balancer by the protrusion. Portable processing machine.

4. The portable processing machine according to claim 3, The protrusion has a shape that functions as a flow straightening portion that directs the air flow in the flow passage radially outward. Portable processing machine.

5. The portable processing machine according to claim 4, Each of the plurality of blades extends at least partially generally radially so as to intersect with a radial direction; The protrusions are arranged in the same direction as the plurality of blades so as to intersect with the radial direction. Portable processing machine.

6. The portable processing machine according to any one of claims 3 to 5, The balancer includes the protrusion. Portable processing machine.

7. A portable processing machine according to any one of claims 1 to 5, The dust collection fan and the motor cooling fan are in the form of an integrated single fan including a main plate having a first surface and a second surface opposite to the first surface, a plurality of first blades extending at least partially radially on the first surface, and a plurality of second blades extending at least partially radially on the second surface. Portable processing machine.

8. A portable processing machine according to any one of claims 1 to 5, The balancer is made of metal. The at least one fan has a specific gravity smaller than that of the balancer. Portable processing machine.

9. 7. The portable processing machine according to claim 6, the at least one fan includes a screw boss protruding toward the balancer; The balancer includes a through hole formed at a position corresponding to the screw boss, the protrusion protrudes toward the at least one fan around the through hole and has a shape and size into which an outer periphery of the screw boss fits, The at least one fan and the balancer are fixed to each other by a screw member that is inserted into the through hole and the screw boss. Portable processing machine.

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