Power tool system and attachment

Abstract

The purpose of the present disclosure is to provide a power tool system capable of reducing kickback. A power tool system (100) comprises: a power tool body (1); and a transmission mechanism (2). The power tool body (1) has an output shaft (12) that rotates by the motive power of a motor. The transmission mechanism (2) transmits the rotation of the output shaft (12) to a hole saw (A1). The transmission mechanism (2) has a planetary gear (213) and a drill unit (4). The planetary gear (213) rotates in conjunction with the rotation of the output shaft (12) in a state in which the relative position with the output shaft (12) is fixed. The drill unit (4) rotates integrally with the planetary gear (213). The drill unit (4) comes into contact with a work target (X1) before the hole saw (A1) comes into contact with the work target (X1).

Description

Power tool systems and attachments

[0001] The present disclosure relates generally to power tool systems and attachments, and more particularly to power tool systems and attachments used in drilling operations.

[0002] Patent Document 1 discloses a power tool including a motor, a drive force transmission unit, a trigger switch, a rotation speed change unit, and a control unit. The drive force transmission unit reduces the drive force of the motor and transmits it to an output shaft. The trigger switch can be pulled by a user. The rotation speed change unit can change the rotation speed of the output shaft when the trigger switch is fully pulled to a lower speed than when there is no limit. The control unit controls the rotation speed of the motor based on the amount of pulling of the trigger switch so that the rotation speed is the speed changed by the rotation speed change unit.

[0003] The power tool (power tool system) described above may be equipped with a tool tip such as a hole saw and used for drilling. In this case, kickback may occur in the power tool when the workpiece changes from a soft material to a hard material during the drilling operation.

[0004] Japanese Patent Application Laid-Open No. 2017-30112

[0005] An object of the present disclosure is to provide a power tool system and an attachment that can reduce kickback.

[0006] A power tool system according to one aspect of the present disclosure includes a power tool body and a transmission mechanism. The power tool body has an output shaft that rotates by power from a motor. The transmission mechanism transmits the rotation of the output shaft to a hole saw. The transmission mechanism includes a planetary gear and a drill part. The planetary gear rotates in conjunction with the rotation of the output shaft while its relative position with respect to the output shaft is fixed. The drill part rotates integrally with the planetary gear. The drill part comes into contact with a workpiece before the hole saw comes into contact with the workpiece.

[0007] An attachment according to one aspect of the present disclosure is configured to be detachably attached to a power tool main body having an output shaft that rotates by the power of a motor, and transmits the rotation of the output shaft to a hole saw. The attachment according to one aspect of the present disclosure includes an attachment-side engaging portion, a planetary gear, and a drill portion. The attachment-side engaging portion detachably engages with a tool-side engaging portion of the power tool main body. The planetary gear rotates in conjunction with the rotation of the output shaft while its relative position with the output shaft is fixed. The drill portion rotates integrally with the planetary gear. The drill portion comes into contact with the workpiece before the hole saw comes into contact with the workpiece.

[0008] Fig. 1 is a cross-sectional view of a power tool system according to the present embodiment. Fig. 2 is an external perspective view of the power tool system. Fig. 3 is a block diagram showing a schematic configuration of the power tool system. Fig. 4 is a cross-sectional view of the power tool system taken along line A-A in Fig. 1.

[0009] Hereinafter, a power tool system according to an embodiment will be described with reference to the drawings. However, the embodiment described below is merely one of various embodiments of the present disclosure. The embodiment described below can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, each diagram described in the embodiment described below is a schematic diagram, and the ratios of the sizes and thicknesses of the components in the diagram do not necessarily reflect the actual dimensional ratios.

[0010] (Present Embodiment) (1) Overview Hereinafter, an overview of a power tool system 100 according to this embodiment will be described with reference to FIG.

[0011] The power tool system 100 according to this embodiment is assumed to be an electric cutting tool to which a hole saw A1 is attached and which is used by a worker for drilling work to drill a circular hole in a work object X1 (board, ceiling, wall, etc.).

[0012] As shown in Fig. 1, the power tool system 100 includes a power tool body 1 and a transmission mechanism 2. The power tool body 1 has an output shaft 12 that rotates by the power of a motor 11 (see Fig. 3). The transmission mechanism 2 transmits the rotation of the output shaft 12 to the hole saw A1.

[0013] The transmission mechanism 2 further includes a planetary gear 213 and a drill unit 4. The planetary gear 213 rotates in conjunction with the rotation of the output shaft 12 while its relative position to the output shaft 12 is fixed. The drill unit 4 rotates integrally with the planetary gear 213. The drill unit 4 comes into contact with the work object X1 before the hole saw A1 comes into contact with the work object X1.

[0014] In the comparative example, when the workpiece changes from a soft material to a hard material during drilling, kickback may occur in the tool body in the direction opposite to the rotation of the hole blade, causing the tool body to rotate and preventing normal drilling.

[0015] However, with the power tool system 100 of this embodiment, before drilling, the rotating drill unit 4 is brought into contact with the work object X1 to create a hole X11 in the work object X1, and the drilling operation can be performed with the drill unit 4 inserted into the hole X11. As a result, if kickback occurs in the power tool main body 1 in the direction opposite to the rotation direction of the hole saw A1, the drill unit 4 can reduce rotation of the power tool main body 1. In other words, the power tool system 100 of this embodiment has the advantage of being able to reduce kickback. Note that the "hole X11" referred to in this disclosure is a hole smaller than the circular hole to be drilled in the drilling operation.

[0016] Furthermore, with the power tool system 100 of this embodiment, there is no need to use a power tool, such as a drill driver, other than the power tool system 100 to pre-drill holes in the work target. In other words, there is no need for pre-work using another power tool, which has the advantage of easily reducing kickback.

[0017] (2) Detailed Configuration (2-1) Power Tool System Hereinafter, the detailed configuration of the power tool system 100 of this embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0018] In the following description, as shown in Fig. 1 , the direction in which the transmission mechanism 2 and the main body 131 (described later) of the power tool main body 1 are aligned is defined as the front-to-rear direction, the side of the transmission mechanism 2 as viewed from the main body 131 is defined as the front, and the side of the main body 131 as viewed from the transmission mechanism 2 is defined as the rear. Also, as shown in Fig. 2 , the direction in which the main body 131 and the grip 132 (described later) are aligned is defined as the up-down direction, the side of the main body 131 as viewed from the grip 132 is defined as the top, and the side of the grip 132 as viewed from the main body 131 is defined as the bottom. Also, the direction perpendicular to the front-to-rear direction and the up-to-down direction is defined as the left-to-right direction. However, these definitions are not intended to define the direction in which the power tool system 100 is used.

[0019] The power tool system 100 is assumed to be an electric cutting tool to which a hole saw A1 is attached and which is used by an operator for drilling a circular hole in a work object X1 (such as a board, ceiling, or wall). The hole saw A1 is a tool tip that cuts a circular hole in the work object X1. As shown in FIG. 2 , the hole saw A1 is cylindrical. More specifically, the hole saw A1 is a cylindrical body with an opening in the front-to-rear direction. A saw blade is formed at the front end of the hole saw A1. In this embodiment, the hole saw A1 is not included in the configuration of the power tool system 100. However, the hole saw A1 may also be included in the configuration of the power tool system 100.

[0020] As shown in FIG. 3 , the power tool system 100 includes a power tool main body 1 and a transmission mechanism 2 .

[0021] In the power tool system 100 of this embodiment, the transmission mechanism 2 is configured to be detachable from the power tool main body 1. In other words, the transmission mechanism 2 is an attachment Y1 (see FIG. 1 ) that is detachably attached to the power tool main body 1.

[0022] (2-2) Power Tool Body Hereinafter, the detailed structure of the power tool body 1 of this embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0023] As shown in FIGS. 2 and 3 , the power tool body 1 includes a motor 11 , an output shaft 12 , a housing 13 , a control unit 14 , an operating unit 15 , and a tool-side engaging unit 6 .

[0024] (Housing) The housing 13 accommodates the motor 11 , at least a portion of the output shaft 12 , the control unit 14 , and the operation unit 15 .

[0025] As shown in FIG. 2 , the housing 13 has a main body portion 131 , a grip portion 132 , and a battery mounting portion 133 .

[0026] The main body 131 accommodates the motor 11 and at least a portion of the output shaft 12 .

[0027] As shown in FIG. 1 , the main body 131 has a side portion 1311 and a bottom portion 1312. The side portion 1311 is tubular. More specifically, the side portion 1311 is cylindrical. The bottom portion 1312 is arranged to cover an opening formed on the rear side of the tubular side portion 1311. In other words, the main body 131 is a bottomed cylinder having an opening on the front side. The bottom portion 1312 is disk-shaped. The thickness direction of the bottom portion 1312 is along the front-rear direction. At least a portion of the output shaft 12 protrudes forward from the opening of the main body 131.

[0028] 1, the transmission mechanism 2 is attached to the front opening of the main body 131. In this embodiment, the transmission mechanism 2 is detachably attached to the front opening of the main body 131.

[0029] As shown in Fig. 2, the grip portion 132 protrudes from the main body portion 131. More specifically, the grip portion 132 protrudes downward from the main body portion 131. An operator can grasp the grip portion 132 to perform work such as tightening a screw. An operator can grasp the grip portion 132 to perform work such as tightening a screw.

[0030] The grip portion 132 of this embodiment houses the control portion 14 .

[0031] The battery mounting section 133 is shaped like a rectangular parallelepiped. As shown in FIG. 2 , the battery mounting section 133 is connected to the lower end of the grip section 132. A rechargeable battery pack A2 is detachably attached to the battery mounting section 133. The power tool body 1 operates using the battery pack A2 as a power source. That is, the battery pack A2 is a power source that supplies power to drive the motor 11. The battery pack A2 is not a component of the power tool body 1. However, the power tool body 1 may be equipped with the battery pack A2. The battery pack A2 includes a battery pack configured by connecting multiple secondary batteries (e.g., lithium ion batteries) in series and a case that houses the battery pack.

[0032] (Motor) The motor 11 performs rotational motion. More specifically, the motor 11 is driven by power supplied from the battery pack A2 attached to the battery mounting section 133 to perform rotational motion. The motor 11 includes a rotor having a drive shaft and a permanent magnet, and a stator having a coil. Electromagnetic interaction between the permanent magnet and the coil causes the rotor to rotate relative to the stator.

[0033] The motor 11 is a servo motor. The torque and rotation speed of the motor 11 change according to control by a control unit 14 (servo driver). More specifically, the control unit 14 controls the operation of the motor 11 by feedback control, which controls the torque and rotation speed of the motor 11 so as to approach target values.

[0034] (Output Shaft) The output shaft 12 is directly or indirectly connected to the drive shaft of the motor 11. As a result, the output shaft 12 rotates in conjunction with the drive shaft of the motor 11. In other words, the output shaft 12 is rotated by the motor 11.

[0035] The output shaft 12 is a columnar body. The output shaft 12 of this embodiment is cylindrical. As shown in FIG. 1 , at least a portion of the output shaft 12 protrudes from the opening of the main body 131. More specifically, a front portion of the output shaft 12 protrudes from the opening of the main body 131.

[0036] The output shaft 12 is configured so that a gear unit 21 (see FIG. 3 ), which will be described later, of the transmission mechanism 2 can be connected to it. More specifically, as shown in FIG. 1 , the output shaft 12 is configured so that a connecting shaft 211, which will be described later, of the gear unit 21 in the transmission mechanism 2 can be connected to it. When the connecting shaft 211 of the gear unit 21 in the transmission mechanism 2 is connected to the output shaft 12, the connecting shaft 211 is rotated together with the output shaft 12 by the motor 11.

[0037] The output shaft 12 also has a holder 121 (see FIG. 1 ) that holds a tool bit when the connecting shaft 211 of the gear unit 21 in the transmission mechanism 2 is not connected. The holder 121 is provided at the front end of the output shaft 12. The tool bit is a tool bit different from the hole saw A1, such as a driver bit. When the holder 121 holds the tool bit, the output shaft 12 rotates with the tool bit engaged with a fastening part, thereby enabling operations such as tightening or loosening the fastening part.

[0038] (Tool-Side Engagement Portion) The tool-side engagement portion 6 is configured to be engageable with a mechanism-side engagement portion 5 (described later) of the transmission mechanism 2. The tool-side engagement portion 6 is provided around the output shaft 12 between the output shaft 12 and the side portion 1311. More specifically, the tool-side engagement portion 6 is provided between the output shaft 12 and the side portion 1311 so as to surround the output shaft 12. In other words, the opening of the main body portion 131 is covered by the output shaft 12 and the tool-side engagement portion 6.

[0039] As shown in FIG. 1 , the tool-side engaging portion 6 of this embodiment has a base portion 60 and a protrusion 61 .

[0040] The base 60 is generally cylindrical in shape. The axial direction of the base 60 is along the front-rear direction. The base 60 is disposed between the output shaft 12 and the side portion 1311 of the housing 13 so as to surround the output shaft 12. That is, the output shaft 12 passes through the inside of the base 60. The dimension of the base 60 in the front-rear direction is smaller than the dimension of the output shaft 12 in the front-rear direction. Therefore, the front end of the output shaft 12 protrudes from the front end of the base 60.

[0041] The protrusion 61 protrudes outward from the front end of the base 60. The protrusion 61 is formed around the circumference of the base 60. As shown in FIG. 1 , when the transmission mechanism 2 is attached to the power tool body 1, the rear surface of the protrusion 61 engages with a mechanism-side engaging portion 5 of the transmission mechanism 2, which will be described later.

[0042] (Operation Unit) As shown in FIG. 1 , the operation unit 15 protrudes from the grip portion 132. The operation unit 15 accepts operations for controlling the rotation of the drive shaft of the motor 11. By pulling the operation unit 15, the motor 11 can be switched on and off. Furthermore, the rotation speed of the drive shaft of the motor 11 can be adjusted by the amount of pulling the operation unit 15. The greater the amount of pulling, the faster the rotation speed of the drive shaft of the motor 11.

[0043] (Control Unit) The control unit 14 rotates or stops the drive shaft of the motor 11 in accordance with the pulling amount of the operation to pull the operation unit 15, and also controls the rotation speed of the drive shaft.

[0044] The control unit 14 includes, for example, a microcontroller. The control unit 14 can change the rotation speed of the output shaft 12 by changing the rotation speed of the drive shaft of the motor 11. The control unit 14 changes the rotation speed of the drive shaft of the motor 11, for example, by changing the power supplied to the motor 11.

[0045] (2-3) Transmission Mechanism Hereinafter, the detailed structure of the transmission mechanism 2 of this embodiment will be described with reference to FIGS.

[0046] The transmission mechanism 2 transmits the rotation of the output shaft 12 of the power tool body 1 to the hole saw A1. When the transmission mechanism 2 is attached to the power tool body 1, the transmission mechanism 2 of this embodiment transmits the rotation of the output shaft 12 of the power tool body 1 to the hole saw A1. More specifically, when the transmission mechanism 2 is attached to the power tool body 1, the transmission mechanism 2 transmits the rotation of the output shaft 12 of the power tool body 1 to the hole saw A1, thereby rotating the hole saw A1.

[0047] 1 and 3, the transmission mechanism 2 includes a drill portion 4, a gear portion 21, a first holding portion 22, a second holding portion 23, a first bearing 24, a second bearing 25, a housing 29 (see FIG. 2), and a mechanism-side engaging portion 5. Note that since the transmission mechanism 2 is an attachment Y1 that is detachably attached to the power tool body 1, the mechanism-side engaging portion 5 is also referred to as an attachment-side engaging portion 5.

[0048] (Gear Section) As shown in Figures 1, 3, and 4, the gear section 21 has a connecting shaft 211, a sun gear 212, planetary gears 213, and a ring gear 214. As shown in Figure 4, the sun gear 212, planetary gears 213, and ring gear 214 are, for example, spur gears. More specifically, the sun gear 212 and planetary gears 213 are external gears having a plurality of external teeth formed on their outer circumferential surfaces. On the other hand, the ring gear 214 is an internal gear having a plurality of internal teeth formed on its inner circumferential surface. Note that Figure 4 is a cross-sectional view taken along line A-A in Figure 1, but hatching is omitted.

[0049] The sun gear 212 is connected to the output shaft 12 and rotates in a first direction D2a (see FIG. 4 ), which is the same direction as the rotational direction of the output shaft 12. As shown in FIG. 1 , the sun gear 212 is connected to the output shaft 12 via the connecting shaft 211 by fitting the connecting shaft 211 into a hole 2121 provided in the center of the sun gear 212. As an example, it is assumed that the output shaft 12 rotates in the clockwise direction, so the first direction D2a shown in FIG. 4 is the clockwise direction, i.e., the right-handed direction.

[0050] With its relative position relative to the output shaft 12 fixed, the planetary gears 213 rotate in a second direction D2b (see FIG. 4 ), which is the opposite direction to the first direction D2a, in conjunction with the rotation of the sun gear 212. In other words, with its relative position relative to the sun gear 212 fixed, the planetary gears 213 rotate in the second direction D2b, which is the opposite direction to the first direction D2a, in conjunction with the rotation of the sun gear 212. That is, the planetary gears 213 do not rotate around the sun gear 212, but rotate in the second direction D2b in conjunction with the rotation of the sun gear 212. In short, the planetary gears 213 rotate in the second direction D2b in conjunction with the rotation of the sun gear 212. Although the planetary gears 213 of this embodiment are not gears that revolve around the sun gear 212, they will be referred to as planetary gears for convenience in this disclosure. Note that "linked to the rotation of the sun gear 212" here means that the external teeth of the sun gear 212 and the external teeth of the planet gears 213 mesh with each other, and the rotational force of the sun gear 212 is transmitted to the planet gears 213. The second direction D2b shown in Figure 4 is the counterclockwise direction, i.e., the left-handed direction.

[0051] The drill part 4 is inserted into a through hole 2131 (see FIG. 4 ) provided in the center of the planetary gear 213, and the drill part 4 is rotatably held by a first holding part 22 and a second holding part 23 described below. In other words, the planetary gear 213 is rotatably held by the first holding part 22 and the second holding part 23 via the drill part 4. The drill part 4 is fixed to the through hole 2131 of the planetary gear 213. Therefore, the drill part 4 rotates (rotates) together with the planetary gear 213 in the second direction D2b.

[0052] In this embodiment, the gear unit 21 has two planetary gears 213. One of the two planetary gears 213 is disposed above the sun gear 212 and rotates in the second direction D2b in conjunction with the sun gear 212 while being fixed to the upper side of the sun gear 212. Similarly, the other of the two planetary gears 213 is disposed below the sun gear 212 and rotates in the second direction D2b in conjunction with the sun gear 212 while being fixed to the lower side of the sun gear 212.

[0053] As shown in Fig. 4 , the ring gear 214 is disposed so as to house the sun gear 212 and the planet gears 213 therein. The ring gear 214 rotates in the second direction D2b in conjunction with the rotation of the planet gears 213. Note that "in conjunction with the rotation of the planet gears 213" here means that the external teeth of the planet gears 213 and the internal teeth of the ring gear 214 mesh with each other, and the rotational force of the planet gears 213 is transmitted to the ring gear 214. The ring gear 214 in this embodiment is disposed so as to house the sun gear 212 and the two planet gears 213 therein, and rotates in the second direction D2b in conjunction with the rotation of the two planet gears 213.

[0054] The hole saw A1 can be fixed to the ring gear 214. More specifically, as shown in FIG. 1 , the ring gear 214 further has a fixing portion 215 to which the hole saw A1 can be fixed. The fixing portion 215 is formed integrally with the ring gear 214 and rotates together with the ring gear 214 in the second direction D2b. In this embodiment, the fixing portion 215 has a cylindrical shape. As shown in FIG. 1 , a groove 2151 is provided on the front surface of the fixing portion 215, into which the hole saw A1 can be removably inserted. When viewed from the front-to-rear direction, the groove 2151 has an annular shape.

[0055] As described above, the gear section 21 has the sun gear 212, the planetary gears 213, and the ring gear 214, which has the advantage that the transmission mechanism 2 can efficiently transmit the rotation of the output shaft 12 to the hole saw A1.

[0056] 1 , the first bearing 24 and the second bearing 25 rotatably support the ring gear 214 and the fixed portion 215. In other words, the first bearing 24 and the second bearing 25 journal the ring gear 214 and the fixed portion 215. More specifically, as shown in FIG. 1 , the first bearing 24 fits between the first holding portion 22 and the fixed portion 215, and the second bearing 25 fits between the second holding portion 23 and the fixed portion 215, thereby rotatably supporting the ring gear 214. Specifically, each of the first bearing 24 and the second bearing 25 is a ball bearing.

[0057] (Drill portion) As shown in Fig. 1 , the drill portion 4 is a long, rod-like member. The longitudinal direction of the drill portion 4 is along the front-rear direction. The drill portion 4 is fixed to the power tool body 1. In this embodiment, the rear end of the drill portion 4 is held by a first holding portion 22.

[0058] The drill unit 4 rotates (spins) integrally with the planetary gear 213 in the second direction D2b (see FIG. 4 ). Furthermore, during drilling, the drill unit 4 contacts the workpiece X1 before the hole saw A1 contacts the workpiece X1. In other words, as shown in FIG. 1 , the tip 41 (front end) of the drill unit 4 is farther from the power tool body 1 than the tip (front end) of the hole saw A1 in the axial direction D1 (front-rear direction) of the output shaft 12 (i.e., is farther from the power tool body 1). In other words, the tip 41 (front end) of the drill unit 4 is located forward of the tip (front end) of the hole saw A1.

[0059] According to the above configuration, in the power tool system 100 of this embodiment, before performing a drilling operation, the rotating drill unit 4 is brought into contact with the work object X1 to form a hole X11 in the work object X1, and the drill unit 4 is inserted into the hole X11 to perform the drilling operation. As a result, if kickback occurs in the power tool main body 1 in the direction opposite to the rotation direction of the hole saw A1, the drill unit 4 can reduce rotation of the power tool main body 1. In other words, the power tool system 100 of this embodiment has the advantage of being able to reduce kickback.

[0060] Furthermore, with the power tool system 100 of this embodiment, there is no need to use a power tool, such as a drill driver, other than the power tool system 100 to pre-drill holes in the work target. In other words, there is no need for pre-work using another power tool, which has the advantage of easily reducing kickback.

[0061] The drill part 4 is disposed at a position that does not overlap with the output shaft 12 when viewed in the axial direction D1 (front-rear direction) of the output shaft 12. In other words, the drill part 4 is disposed at a position that does not overlap with the rotation axis of the hole saw A1 when viewed in the axial direction D1 (front-rear direction) of the output shaft 12. As a result, when kickback occurs in the power tool main body 1 in the direction opposite to the rotation direction of the hole saw A1, the drill part 4 can further reduce rotation of the power tool main body 1. In other words, the power tool system 100 of this embodiment has the advantage of being able to further reduce kickback.

[0062] The tip 41 (front end) of the drill unit 4 has a shape that allows it to leave a mark on the work object X1. More specifically, the tip 41 of the drill unit 4 has a sharp shape. In the example of FIG. 1 , the tip 41 has a truncated cone shape whose cross-sectional area decreases toward the tip. The above configuration has the effect of easily marking the location where the hole X11 will be drilled by pressing the non-rotating drill unit 4 (i.e., the drill unit 4 before rotating) against the work object X1 before the hole X11 is drilled. This has the advantage of making it easier to drill the hole X11 into the work object X1 through which the drill unit 4 is inserted.

[0063] 1, the drill part 4 is rotatably held by a first holding part 22 and a second holding part 23. Each of the first holding part 22 and the second holding part 23 is an annular member having an opening in the front-rear direction. The drill part 4 is inserted into each of the first holding part 22 and the second holding part 23, thereby being rotatably held.

[0064] The transmission mechanism 2 of this embodiment has multiple (two) drill units 4. As shown in FIG. 2 , the two drill units 4 are arranged side by side in the vertical direction. The two drill units 4 correspond one-to-one to the two planetary gears 213, and the two drill units 4 are inserted into the through holes 2131 of the corresponding planetary gears 213 and rotate (spin on their axes) in the second direction D2b together with the corresponding planetary gears 213. By having the multiple drill units 4 in the transmission mechanism 2, the power tool system 100 has the advantage of being able to further reduce kickback.

[0065] (Housing) The housing 29 accommodates the mechanism-side engaging portion 5, at least a portion of the connecting shaft 211, and at least a portion of the drill portion 4. Specifically, the housing 29 accommodates the mechanism-side engaging portion 5, the rear portion of the connecting shaft 211, and the rear portion of the drill portion 4.

[0066] The housing 29 has a generally cylindrical shape. More specifically, the housing 29 has a generally cylindrical shape. The housing 29 has openings in the front-rear direction. That is, the housing 29 is a cylinder having openings on the front and rear sides.

[0067] (Mechanism-Side Engagement Portion) The mechanism-side engagement portion 5 is configured to be engageable with the tool-side engagement portion 6 of the power tool body 1. As a result, there is an advantage that the transmission mechanism 2 can be detachably attached to the power tool body 1.

[0068] As shown in FIG. 1 , the transmission mechanism 2 of this embodiment includes two mechanism-side engaging portions 5. Each of the two mechanism-side engaging portions 5 has a protrusion 51 that protrudes inward. The thickness direction of the two protrusions 51 is aligned with the front-to-rear direction. The two protrusions 51 are arranged side by side in the vertical direction. The upper protrusion 51 protrudes downward, and the lower protrusion 51 protrudes upward. When the transmission mechanism 2 is attached to the power tool body 1, the front faces of the two protrusions 51 engage with the rear faces of the convex portions 61 of the tool-side engaging portions 6.

[0069] In this embodiment, the two mechanism side engaging portions 5 are configured so that the engagement between the protrusion 51 and the convex portion 61 of the tool side engaging portion 6 is released when the operating portion 52 is slid forward.

[0070] (3) Modifications The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. The following modifications may be realized in appropriate combination.

[0071] Although the transmission mechanism 2 in the above-described embodiment has two drill portions 4, it may have three or more drill portions 4. Furthermore, the transmission mechanism 2 may have one drill portion 4. That is, it is sufficient for the transmission mechanism 2 to have at least one drill portion 4.

[0072] Although the gear unit 21 in the above-described embodiment has two planetary gears 213, it may have three or more planetary gears 213. In the above-described case, when the transmission mechanism 2 has two drill units 4, the two drill units 4 correspond one-to-one to two of the three or more planetary gears 213, and the two drill units 4 are inserted into the through holes 2131 of the corresponding planetary gears 213 and rotate (spin on their axes) in the second direction D2b together with the corresponding planetary gear 213. Furthermore, although the gear unit 21 in the above-described embodiment has two planetary gears 213, it may have one planetary gear 213.

[0073] In the power tool system 100 of the above embodiment, the transmission mechanism 2 is configured to be detachable from the power tool body 1, but it may also be configured as an integral part of the power tool body 1. That is, the transmission mechanism 2 may be configured not to be detachable from the power tool body 1. In other words, the transmission mechanism 2 does not have to be the attachment Y1 that is detachably attached to the power tool body 1.

[0074] (Summary) A power tool system (100) of a first aspect includes a power tool main body (1) and a transmission mechanism (2). The power tool main body (1) has an output shaft (12) that rotates by the power of a motor (11). The transmission mechanism (2) transmits the rotation of the output shaft (12) to a hole saw (A1). The transmission mechanism (2) has a planetary gear (213) and a drill part (4). The planetary gear (213) rotates in conjunction with the rotation of the output shaft (12) while its relative position with respect to the output shaft (12) is fixed. The drill part (4) rotates integrally with the planetary gear (213). The drill part (4) comes into contact with the work object (X1) before the hole saw (A1) comes into contact with the work object (X1).

[0075] This embodiment has the advantage of being able to reduce kickback.

[0076] In the power tool system (100) of the second aspect, in the first aspect, the transmission mechanism (2) further includes a sun gear (212) and a ring gear (214). The sun gear (212) is connected to the output shaft (12) and rotates in a first direction (D2a) that is the same direction as the rotational direction of the output shaft (12). The hole saw (A1) can be fixed to the ring gear (214), which rotates in conjunction with the rotation of the planetary gears (213). The planetary gears (213), while their relative positions with the output shaft (12) are fixed, rotate in a second direction (D2b) that is the opposite direction to the first direction (D2a) in conjunction with the rotation of the sun gear (212). The ring gear (214) rotates in the second direction (D2b) in conjunction with the rotation of the planetary gears (213).

[0077] This embodiment has the advantage that the rotation of the output shaft (12) can be efficiently transmitted to the hole saw (A1).

[0078] The power tool system (100) of the third aspect is the first or second aspect, wherein the tip (41) of the drill part (4) has a shape that allows it to leave a mark on the work object (X1).

[0079] This embodiment has the advantage that the hole (X11) into which the drill part (4) is inserted can be easily formed in the work object (X1).

[0080] The fourth aspect of the power tool system (100) is any one of the first to third aspects, in which the transmission mechanism (2) further has a mechanism-side engaging portion (5) that detachably engages with the tool-side engaging portion (6) of the power tool body (1).

[0081] This embodiment has the advantage that the transmission mechanism (2) can be detachably attached to the power tool body (1).

[0082] The power tool system (100) of the fifth aspect is any one of the first to fourth aspects, wherein the transmission mechanism (2) has a plurality of drill portions (4).

[0083] This embodiment has the advantage that kickback can be further reduced.

[0084] The sixth aspect of the power tool system (100) is any of the first to fifth aspects, in which the drill portion (4) is positioned so as not to overlap with the output shaft (12) when viewed from the axial direction (D1) of the output shaft (12).

[0085] This embodiment has the advantage that kickback can be further reduced.

[0086] The seventh aspect of the attachment (Y1) is detachably attached to a power tool body (1) having an output shaft (12) that rotates by the power of a motor (11), and transmits the rotation of the output shaft (12) to a hole saw (A1). The seventh aspect of the attachment (Y1) includes an attachment-side engaging portion (5), a planetary gear (213), and a drill portion (4). The attachment-side engaging portion (5) detachably engages with a tool-side engaging portion (6) of the power tool body (1). The planetary gear (213) rotates in conjunction with the rotation of the output shaft (12) while its relative position with the output shaft (12) is fixed. The drill portion (4) rotates integrally with the planetary gear (213). The drill portion (4) comes into contact with the work object (X1) before the hole saw (A1) comes into contact with the work object (X1).

[0087] This embodiment has the advantage of being able to reduce kickback.

[0088] REFERENCE SIGNS LIST 100 Power tool system 1 Power tool body 11 Motor 12 Output shaft 2 Transmission mechanism 212 Sun gear 213 Planetary gear 214 Ring gear 4 Drill part 41 Tip 5 Mechanism side engagement part (attachment side engagement part) 6 Tool side engagement part A1 Hole saw D1 Axial direction D2a First direction D2b Second direction X1 Work object Y1 Attachment

Claims

1. A power tool system comprising: an electric power tool body having an output shaft that rotates by the power of a motor; and a transmission mechanism that transmits the rotation of the output shaft to a hole saw, wherein the transmission mechanism has: a planetary gear that rotates in conjunction with the rotation of the output shaft while its relative position to the output shaft is fixed; and a drill part that rotates integrally with the planetary gear, and wherein the drill part comes into contact with the work object before the hole saw comes into contact with the work object.

2. The power tool system described in claim 1, wherein the transmission mechanism further includes a sun gear connected to the output shaft and rotating in a first direction that is the same as the rotational direction of the output shaft, and a ring gear to which the hole saw can be fixed and which rotates in conjunction with the rotation of the planetary gears, wherein the planetary gears rotate in a second direction that is opposite to the first direction in conjunction with the rotation of the sun gear while their relative positions to the output shaft are fixed, and the ring gear rotates in the second direction in conjunction with the rotation of the planetary gears.

3. The power tool system according to claim 1 or 2, wherein the tip of the drill part has a shape that allows it to leave a mark on the work object.

4. A power tool system according to any one of claims 1 to 3, wherein the transmission mechanism further comprises a mechanism-side engaging portion that detachably engages with a tool-side engaging portion of the power tool body.

5. The power tool system according to any one of claims 1 to 4, wherein the transmission mechanism has a plurality of the drill parts.

6. The power tool system according to any one of claims 1 to 5, wherein the drill part is positioned so as not to overlap with the output shaft when viewed in the axial direction of the output shaft.

7. An attachment that is detachably attached to an electric tool body having an output shaft that rotates by the power of a motor, and transmits the rotation of the output shaft to a hole saw, comprising: an attachment-side engaging portion that detachably engages with a tool-side engaging portion of the electric tool body; a planetary gear that rotates in conjunction with the rotation of the output shaft while its relative position with the output shaft is fixed; and a drill portion that rotates integrally with the planetary gear, wherein the drill portion comes into contact with the work object before the hole saw comes into contact with the work object.

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