Die grinder

Abstract

To provide a die grinder that can grip the gripping part appropriately while suppressing an increase in size. [Solution] The die grinder comprises a motor, a spindle, and a main housing. The spindle rotates around a drive axis that defines the front-rear direction of the die grinder by the power of the motor. The main housing includes a motor housing, a handle housing, and a battery housing. The motor housing houses the motor. The handle housing has an elongated gripping section connected to the rear end of the motor housing and configured for the user to grip. The battery housing has a battery mounting section connected to the rear end of the handle housing and capable of housing a battery. The battery mounting section is positioned where the drive axis passes through and can accommodate a battery in a direction perpendicular to the drive axis. The central axis of the gripping section is positioned radially outward from the drive axis.

Description

Technical Field

[0006] , , ,

[0001] The present disclosure relates to a die grinder.

Background Art

[0002] Rotary tools (for example, die grinders and disk grinders) configured to perform machining operations such as grinding and polishing on a workpiece by rotationally driving a tip tool attached to a spindle are known. For example, Patent Document 1 discloses a disk grinder including a grip portion that can be gripped by a user and configured such that a spindle rotates by the rotation of a motor by power supplied from a battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a user can suitably grip the grip portion, the workability of the rotary tool can be improved. However, for example, simply extending the length of the grip portion in the front-rear direction may increase the overall length of the rotary tool and cause the rotary tool to become larger. Therefore, there is a need for a rotary tool that can suitably grip the grip portion while suppressing an increase in the size of the rotary tool. A die grinder is generally more likely to be used in a narrow space than a disk grinder. Therefore, in a die grinder, such problems can become more prominent.

[0005] One non-limiting object of the present disclosure is to provide a die grinder that can suitably grip a grip portion while suppressing an increase in the size of the die grinder.

Means for Solving the Problems

[0006] A die grinder is provided according to one non-limiting aspect of the present disclosure. The die grinder comprises a motor, a spindle, and a main housing. The motor is driven by power supplied from a battery. The spindle rotates by the power of the motor about a drive axis that defines the front-rear direction of the die grinder. The main housing includes a motor housing, a handle housing, and a battery housing. The motor housing houses the motor. The handle housing has an elongated gripping portion connected to the rear end of the motor housing and configured to be gripped by a user. The battery housing has a battery mounting portion connected to the rear end of the handle housing and capable of housing the battery. The battery mounting portion is positioned on which the drive axis passes and the battery can be mounted in a direction perpendicular to the drive axis. The central axis of the gripping portion is positioned radially outward from the drive axis.

[0007] According to the die grinder of this embodiment, compared to the case where the battery is mounted at an angle in the battery mounting section, the length of the battery housing in the front-rear direction can be shortened, and the length of the gripping section, which is easy to grip, can be secured. Therefore, it is possible to provide a die grinder that can suitably grip the gripping section while suppressing an increase in the size of the die grinder.

[0008] According to one non-limiting aspect of the present disclosure, a die grinder is provided. The die grinder comprises a motor, a spindle, and a main housing. The motor is powered by a battery. The spindle is rotationally driven by the motor around a drive axis that defines the front-rear direction of the die grinder. The main housing includes a motor housing, a handle housing, a tool housing, and a battery housing. The motor housing houses the motor. The handle housing is connected to the rear end of the motor housing and has an elongated gripping portion configured for a user to grip. The tool housing is connected to the front end of the motor housing and houses the spindle. The battery housing is connected to the rear end of the handle housing and has a battery mounting portion into which the battery can be mounted. In the front-rear direction, the length of the main housing from the rear end of the battery housing to the front end of the tool housing is 400 mm or less.

[0009] According to this embodiment of the die grinder, the length of the main housing in the front-to-back direction is 400 mm or less, which is shorter than the main housing of a typical die grinder. Therefore, it is possible to provide a die grinder that can be suitably used even in confined spaces. [Brief explanation of the drawing]

[0010] [Figure 1] A perspective view showing the external configuration of a die grinder according to the first embodiment. [Figure 2] A cross-sectional view showing the internal configuration of a die grinder according to the first embodiment. [Figure 3] A cross-sectional view showing the internal configuration of the handle housing and battery housing. [Figure 4] A cross-sectional view showing the internal configuration of the motor housing and tool housing. [Figure 5] A cross-sectional view showing the configuration of the shaft lock mechanism. [Figure 6] An explanatory diagram showing the length of the die grinder in the front-to-back direction. [Figure 7] A cross-sectional view showing the position VII-VII in Figure 6. [Figure 8] A cross-sectional view showing the configuration of a die grinder according to the second embodiment. [Modes for carrying out the invention]

[0011] Representative and non-limiting examples of the present invention will be described in detail below with reference to the drawings. This detailed description is intended simply to show those skilled in the art details for carrying out preferred examples of the present invention and is not intended to limit the scope of the invention. In addition, the additional features and inventions disclosed below may be used separately from or in conjunction with the other features and inventions to provide further improved apparatus, methods for manufacturing and using the same.

[0012] Furthermore, the combinations of features and processes disclosed in the following detailed description are not essential for carrying out the present invention in the broadest sense, and are described solely to illustrate representative examples of the present invention. Moreover, the various features of the representative examples described above and below, as well as the various features described in the independent and dependent claims, do not necessarily have to be combined in the same way as the examples described herein or in the order listed, in order to provide additional and useful embodiments of the present invention.

[0013] All features described herein and / or in the claims are intended to be disclosed individually and independently of each other, as limitations to the original disclosure and claimed specifics, separate from the configurations of features described in the embodiments and / or in the claims. Furthermore, all descriptions relating to numerical ranges and groups or clusters are intended to disclose intermediate configurations therein, as limitations to the original disclosure and claimed specifics.

[0014] In one non-limiting embodiment of the present disclosure, when the direction in which the battery is mounted in the battery mounting portion is defined as the vertical direction, the die grinder may be configured such that, when viewed from the side, it passes through the midpoint between the upper end of the battery attached to the battery mounting portion and the lower end of the battery. According to this embodiment, the user can easily move the die grinder along the drive axis and operate the die grinder in a balanced manner. Therefore, the workability of the die grinder can be improved.

[0015] In addition to the above embodiments, or in place of the above embodiments, a controller configured to control the drive of the motor may be provided. The controller may be positioned at a location through which the drive axis passes. The controller may extend in a direction perpendicular to the drive axis when the die grinder is viewed from the side. According to this embodiment, since the controller is positioned on the drive axis, it is possible to suppress or prevent the main housing from becoming larger in the radial direction. In addition, the length of the main housing in the front-rear direction can be shortened compared to when the controller is positioned at an angle to the drive axis.

[0016] In addition to, or in place of, the above-described embodiment, the controller may be housed in the main housing on the side rearward of the gripping portion. According to this embodiment, by housing the controller in the battery housing, which is easier to create internal space in compared to the motor housing and handle housing, the controller can be efficiently positioned within the main housing, thereby suppressing or preventing an increase in the size of the main housing.

[0017] In addition to or in lieu of the above embodiments, the main housing may be provided with an intake port that allows external air to be introduced into the main housing, and the controller may be positioned so as to overlap at least a portion of the intake port when the die grinder is viewed from the side. According to this embodiment, while air-cooling the controller, the length of the main housing in the front-rear direction can be shortened compared to the case where the controller and the intake hole are arranged at different positions.

[0018] In addition to or instead of the above embodiment, the motor may include a stator including a stator core, a rotor, and a motor shaft that rotates together with the rotor. The motor may be housed in the motor housing such that the rotation axis of the motor shaft is parallel to the front-rear direction. The length of the stator core in the front-rear direction may be 30 mm or less. According to this embodiment, the motor is configured such that the length of the motor in the front-rear direction is relatively short. Therefore, while suppressing the extension of the length of the die grinder in the front-rear direction, the length of the gripping portion in the front-rear direction can be extended.

[0019] In addition to or instead of the above embodiment, further, a shaft lock mechanism capable of fixing the spindle in a state where the rotation of the spindle is stopped may be provided. According to this embodiment, a die grinder convenient for replacing the tip tool can be provided.

[0020] In addition to or instead of the above embodiment, further, a coupling for connecting the motor shaft and the spindle may be provided such that the rotation axis of the motor shaft of the motor and the drive axis are coaxial. The shaft lock mechanism may be configured to be able to fix the spindle by locking the shaft lock mechanism and the coupling. According to this embodiment, by using the coupling, it is possible to prevent an increase in the number of parts of the die grinder and to prevent the length of the die grinder in the front-rear direction from becoming long.

[0021] In addition to the above embodiments, or in place of the above embodiments, a switch may be provided to switch the motor on and off in response to the user's operation of the first operating unit. The switch may be housed in the gripping unit. According to this embodiment, it is possible to prevent the length of the die grinder in the front-to-back direction from becoming longer compared to when the switch is housed in the motor housing or battery housing.

[0022] In addition to, or in place of, the above embodiment, a second operating section capable of adjusting the rotational speed of the motor may be provided. The second operating section may be provided behind the gripping section. According to this embodiment, by providing the dial in the battery housing, which has more internal space compared to the motor housing and handle housing, the dial can be efficiently arranged in the main housing, thereby suppressing or preventing an increase in the size of the main housing.

[0023] In addition to or in lieu of the above embodiments, the length from the rear end to the front end of the gripping portion in the front-rear direction may be 60 mm or more. According to this embodiment, the gripping portion is longer than the gripping portion in a typical die grinder. Therefore, the user can grip the gripping portion comfortably, improving the usability of the die grinder.

[0024] In addition to the above embodiments, or in place of the above embodiments, the circumference of the gripping portion in a cross-section perpendicular to the drive axis may be 150 mm or less. According to this embodiment, the gripping portion is thinner than that of a typical die grinder. Therefore, the user can grip the gripping portion more effectively, improving the usability of the die grinder.

[0025] In addition to or in lieu of the above embodiments, the length of the main housing from the rear end of the battery housing to the front end of the motor housing in the front-rear direction may be 260 mm or less. In this embodiment, the length from the rear end of the battery housing to the front end of the motor housing in the front-to-back direction is shorter than the length from the rear end of the battery housing to the front end of the motor housing in a typical die grinder. Because the rear half of the main housing is relatively short, the die grinder can be operated in a balanced manner by gripping the gripping part.

[0026] A. First Embodiment: A1. External configuration of die grinder 100: As shown in Figure 1, the die grinder 100 is an example of a rotary tool that rotates a removable tool bit held at its tip. The die grinder 100 rotates the spindle 90 around the drive axis TX by the rotational force generated by the motor. The tool bit TA is attached to the tip of the spindle 90 and rotates with the rotation of the spindle 90. The die grinder 100 is sometimes also called a "hand grinder" or "straight grinder".

[0027] In the example shown in Figure 1, the tip tool TA is a roughly cylindrical mounted grinding wheel. The side surface TS of the tip tool TA functions as a grinding surface. The user can perform machining operations such as grinding and polishing by, for example, operating the die grinder 100 to rotate the tip tool TA and pressing the side surface TS of the tip tool TA against the workpiece. The shape of the tip tool TA may be changed to various shapes, including conical shapes such as cones, depending on the type of workpiece and the purpose of the machining operation. The tip tool TA is not limited to grinding wheels; other tools such as a flap wheel with sanding paper attached may also be used.

[0028] The die grinder 100 includes a substantially cylindrical main housing 10 that extends in the direction of the drive axis TX. The main housing 10 includes a battery housing 80, a handle housing 40, a motor housing 30, and a tool housing 50.

[0029] A2. Configuration of the battery housing 80: As shown in Figure 1, the battery housing 80 is located at the rear end of the main housing 10. An air intake vent 82 is formed on the side of the battery housing 80. The air intake vent 82 guides air into the main housing 10 to cool the motor 20 and other components.

[0030] As shown in Figure 2, the battery housing 80 has a battery mounting section 86 for removably mounting a rechargeable battery BT. The battery BT is a well-known secondary battery, such as a lithium-ion battery containing multiple cells.

[0031] The battery mounting section 86 is located at the rear end of the handle housing 40, at a position through which the drive axis TX passes. Note that in Figure 2, the battery BT is omitted from the illustration for illustrative purposes. The battery mounting section 86 comprises a pair of rails and terminals electrically connectable to the terminals of the battery BT. The pair of rails of the battery mounting section 86 physically engage with a pair of grooves formed in the battery BT. As a result, the battery BT is guided in a direction perpendicular to the drive axis TX and is attached to and detached from the battery mounting section 86.

[0032] For the sake of clarity, in this specification, the direction in which the drive axis TX extends is defined as the longitudinal direction of the die grinder 100. In the longitudinal direction, the side on which the spindle 90 is located is defined as the front side of the die grinder 100, and the opposite side is defined as the rear side of the die grinder 100. The direction perpendicular to the longitudinal direction, in which the battery BT is attached to and detached from the battery mounting section 86, is defined as the vertical direction. The direction perpendicular to both the vertical and horizontal directions is defined as the left-right direction of the die grinder 100. Furthermore, any direction perpendicular to the drive axis TX is defined as the radial direction of the die grinder 100, with the direction away from the drive axis TX being defined as the radially outward direction, and the direction approaching the drive axis TX being defined as the radially inward direction.

[0033] As shown in Figure 3, the mounting direction of the battery BT is perpendicular to the drive axis TX and defines the vertical direction of the die grinder 100. The user can remove the battery BT from the battery mounting section 86 by pulling the battery BT upward. The user can also install the battery BT into the battery mounting section 86 by pushing the battery BT downward. The battery BT installed in the battery mounting section 86 can supply power to the motor 20, controller 84, etc.

[0034] In this embodiment, the mounting direction of the battery BT is configured to be perpendicular to the drive axis TX. Compared to the case where the mounting direction of the battery BT is inclined with respect to the drive axis TX, this prevents the battery mounting portion 86 and the battery BT from protruding toward the rear. Therefore, compared to the case where the battery BT is inclined and mounted on the battery mounting portion 86, the length of the battery housing 80 in the front-rear direction can be shortened. Thus, while suppressing the extension of the length of the die grinder 100 in the front-rear direction, the length of the gripping portion 42 can be extended by the amount by which the length of the battery housing 80 has been shortened. Therefore, a die grinder 100 that can suitably grip the gripping portion 42 can be provided. Note that if the length of the gripping portion 42 is sufficiently secured, the length of the die grinder 100 in the front-rear direction may be shortened.

[0035] As shown in Figure 3, in the die grinder 100 of this embodiment, the drive axis TX is configured to pass through the midpoint BC between the upper end BU and the lower end BD of the battery BT, which is attached to the battery mounting section 86, when the die grinder 100 is viewed from the side. This configuration makes it easy for the user to move the die grinder 100 along the drive axis TX and to operate the die grinder 100 in a balanced manner. Furthermore, compared to the case where the midpoint BC of the battery BT is shifted radially outward from the drive axis TX, it is possible to prevent the battery BT from protruding radially outward from the main housing 10. Therefore, it is possible to suppress or prevent the die grinder 100 from becoming larger radially outward around the drive axis TX. Although not shown in detail in the illustration, in this embodiment, the drive axis TX is also configured to pass through the midpoint between the left end and the right end of the battery BT.

[0036] As shown in Figure 3, the battery housing 80 is further provided with a dial 88 and a controller 84. As shown in Figure 1, the dial 88 is exposed to the outside from the battery housing 80 and is rotatable by manual operation by the user. Depending on the rotation position, the dial 88 outputs a signal to the controller 84 for setting the rotation speed of the motor.

[0037] As shown in Figure 3, the controller 84 is composed of a computer with a CPU as a central processing unit and memory such as RAM and ROM. The controller 84 is a plate-shaped member including a circuit board. The controller 84 controls various operations in the die grinder 100, such as drive control of the motor 20.

[0038] The controller 84 is positioned where the drive axis TX passes. This configuration suppresses or prevents the main housing 10 from becoming radially larger compared to when the controller 84 is positioned radially outward from the drive axis TX.

[0039] The controller 84 is located in the battery housing 80, which is located behind the handle housing 40. By housing the controller 84 in the battery housing 80, which has more internal space compared to the motor housing 30 and the handle housing 40, the controller 84 can be efficiently positioned within the main housing 10, thereby suppressing or preventing an increase in the size of the main housing 10.

[0040] The controller 84 is positioned to extend in a direction perpendicular to the drive axis TX. Specifically, the circuit board constituting the controller 84 is positioned to extend in the vertical and horizontal directions. This configuration allows for a reduction in the length of the main housing 10 in the front-rear direction compared to the case where the controller 84 is positioned at an angle to the drive axis TX.

[0041] The controller 84 is positioned in approximately the same location as the intake port 82 in the front-to-rear direction. Specifically, when the die grinder 100 is viewed from the side, the controller 84 is positioned so as to overlap at least a portion of the intake port 82 in the front-to-rear direction. This configuration allows the controller 84 to be air-cooled using the air introduced from the intake port 82, while also shortening the length of the main housing 10 in the front-to-rear direction compared to the case where the controller 84 and the intake port 82 are positioned in different locations in the front-to-rear direction.

[0042] A3. Configuration of the handle housing 40: As shown in Figure 2, the handle housing 40 is positioned between the motor housing 30 and the battery housing 80. The handle housing 40 includes a gripping portion 42. The boundary between the handle housing 40 and the battery housing 80 in the front-rear direction is the position of the front end of the components housed in the battery housing 80, such as the controller 84 and the dial 88. In this embodiment, the position of the front end of the dial 88 is the boundary between the handle housing 40 and the battery housing 80.

[0043] The gripping portion 42 has a long, cylindrical shape extending in the front-rear direction. The gripping portion 42 is thinner than the motor housing 30 and the battery housing 80, and is configured to be gripped by the user. The gripping portion 42 is configured to have a thickness (outer diameter), length, and cross-sectional shape that is easy for the user to grip. The detailed configuration of the gripping portion 42 will be described later.

[0044] A4. Configuration of the motor housing 30: As shown in Figure 2, the motor housing 30 is positioned between the handle housing 40 and the tool housing 50. The motor housing 30 is a long, cylindrical housing extending in the front-rear direction and houses the motor 20. The boundary between the motor housing 30 and the handle housing 40 in the front-rear direction is, for example, the position of the rear end of the motor 20.

[0045] As shown in Figure 2, a switch knob 34 is provided above the motor housing 30. The switch knob 34 moves between the off position and the on position in response to manual operation by the user. The switch knob 34 is operably connected to a switch 14. The switch 14 is located on the gripping portion 42. The switch 14 is turned on and off in response to the user's operation of the switch knob 34, switching the motor 20 on and off. The motor 20 is driven while the switch 14 is in the on position.

[0046] As shown in Figure 4, the motor 20 is a brushless DC motor driven under the control of the controller 84. The motor 20 comprises a motor body 21, a motor shaft 22, and a fan 26 attached to the motor shaft 22.

[0047] The motor body 21 includes a stator 212, which contains a stator core 212C, and a rotor 214. The stator core 212C is formed by laminating multiple electromagnetic steel sheets. The stator 212 uses the magnetic field generated by the DC current supplied from the battery to rotate the rotor 214. The rotation of the rotor 214 causes the motor shaft 22 to rotate around the motor rotation axis MX. The volume of the stator core 212C affects the output (rotational speed and torque) of the motor 20.

[0048] In this embodiment, the die grinder 100 can be designed with a lower motor output than a handheld electric disc grinder, taking into consideration its intended use. An electric disc grinder is an example of a rotary tool that performs processing operations such as grinding, polishing, and cutting using, for example, grinding wheels, cutting wheels, blades, brushes, etc., as tip tools. An electric disc grinder is sometimes also called an angle grinder.

[0049] In the die grinder 100 of this embodiment, as shown in Figure 4, the distance LC in the front-rear direction of the stator core 212C, that is, the thickness of the stator core 212C, is configured to be relatively thin. Specifically, in a motor used in a typical electric disc grinder, the thickness of the stator core is, for example, thicker than 30 mm and 80 mm or less. In the motor 20 used in the die grinder 100 of this embodiment, the thickness of the stator core 212C is 24.15 mm, which is 30 mm or less. As a result, the length of the motor housing 30 in the front-rear direction is shortened compared to an electric disc grinder. In this way, the die grinder 100 of this embodiment is configured to ensure the output of the motor 20 required for the die grinder 100 while making the length of the motor 20 in the front-rear direction relatively short.

[0050] As shown in Figure 4, the motor shaft 22 is rotatably supported within the motor housing 30 by a front bearing 201 and a rear bearing 202 provided within the motor housing 30. The front bearing 201 is supported within the motor housing 30 with its movement restricted by a motor bearing retainer 32. The motor bearing retainer 32 has an opening 322 that communicates with an exhaust hole 58 (see Figure 1) formed in the tool housing 50.

[0051] The motor shaft 22 rotates together with the rotor 214 around the motor rotation axis MX. In this embodiment, the motor shaft 22 is connected to the spindle 90 via a coupling 204. The motor shaft 22 and the spindle 90 are connected by the coupling 204 such that the motor rotation axis MX and the drive axis TX are coaxial. By arranging the motor rotation axis MX and the drive axis TX coaxially, it is possible to suppress or prevent the die grinder 100 from becoming larger in the radial direction. However, the motor rotation axis MX and the drive axis TX do not necessarily have to be coaxial; for example, they may be configured to be close to and parallel to each other.

[0052] The fan 26 rotates together with the motor shaft 22. The fan 26 generates an airflow to cool the motor 20. More specifically, as shown in Figure 2, the rotation of the fan 26 directs outside air into the battery housing 80 through an intake port 82 formed in the battery housing 80. The air directed into the battery housing 80 flows forward through the handle housing 40 and is directed to the motor housing 30. The air directed into the motor housing 30 passes through an opening 322 and is discharged to the outside through an exhaust port 58 (see Figure 1) formed in the tool housing 50.

[0053] Furthermore, the space defined inside the gripping portion 42 functions as a passage for airflow to cool the motor 20 and controller 84. Therefore, the thickness of the gripping portion 42, more specifically, the outer shape of the gripping portion 42 in a cross-section perpendicular to the drive axis TX, affects the size of the passage. In the die grinder 100 of this embodiment, as described above, the output of the motor 20 is smaller than that of a typical electric disc grinder motor, so the temperature rise of the motor 20 when using the die grinder 100 is lower than that of an electric disc grinder motor. Therefore, it is possible to set the cooling performance of the motor 20 and controller 84 by air cooling using the fan 26 to be lower than that of an electric disc grinder. For this reason, in this embodiment, the gripping portion 42 is designed to be thinner than the gripping portion of an electric disc grinder so that the user can grip the gripping portion 42 comfortably. However, the thickness of the gripping portion 42 may be the same as that of an electric disc grinder. Furthermore, the cooling performance of the die grinder 100 by air cooling may be considered equivalent to that of an electric disc grinder.

[0054] A5. Configuration of the tool housing 50: As shown in Figure 2, the tool housing 50 is located at the front end of the main housing 10. The tool housing 50 is connected to the front end of the motor housing 30. It houses the spindle 90. The tool housing 50 is configured to have a thickness (outer diameter), length, and cross-sectional shape that is easy for the user to grip.

[0055] As shown in Figure 4, the tool housing 50 houses a barrel 60. The barrel 60 houses a spindle 90. The spindle 90 is rotatably supported relative to the barrel 60 by a front bearing 601 and a rear bearing 602, which are held within the barrel 60. The front bearing 601 is fixed by a bearing retainer 66, which restricts its movement in the forward and backward directions.

[0056] The front end of the spindle 90 is provided with a collet cone 92 and a collet nut 94 for securing the tool tip TA to the spindle 90. The tool tip TA is inserted into the collet cone 92 and the collet nut 94 is tightened, thereby preventing rotation of the tool from being attached to the spindle 90.

[0057] When the user manually operates the switch knob 34 and the motor 20 is turned on, the motor shaft 22 is driven. The spindle 90 and the tool tip TA rotate together with the motor shaft 22 via the coupling 204.

[0058] A6. Shaft locking mechanism: As shown in Figure 5, the die grinder 100 of this embodiment is equipped with a shaft lock mechanism 70. The shaft lock mechanism 70 fixes the spindle 90 in a state where the rotation of the spindle 90 is stopped. The shaft lock mechanism 70 prevents the collet nut 94 and the spindle 90 from rotating together with the main housing 10 when the tip tool TA is replaced. As shown in Figure 5, the shaft lock mechanism 70 includes a button 72, a pin 74, a biasing member 76, and a fitting portion 78.

[0059] Button 72 functions as an operating part that can switch the shaft lock mechanism 70 on and off. The outer surface of button 72 is exposed to the outside of the tool housing 50. The inner surface of button 72 faces the barrel 60. A recess 724 capable of receiving the biasing member 76 is formed on the inner surface of button 72.

[0060] The biasing member 76 is a metal coil spring. The biasing member 76 is positioned in a recess 604 formed on the outer surface of the barrel 60. The biasing member 76 biases the recess 604 and the recess 724 of the button 72 in a direction away from each other.

[0061] The pin 74 has an elongated, roughly cylindrical shape. The pin 74 is inserted through a through hole 606 formed in the barrel 60. In the example of Figure 5, the through hole 606 extends in the vertical direction. However, the through hole 606 may extend in any direction perpendicular to the drive axis TX, such as the left-right direction. The pin 74 is positioned in the through hole 606 such that the tip 746 of the pin 74 faces the coupling 204.

[0062] The pin 74 has a second connecting portion 742 and a restricting portion 744. The second connecting portion 742 is a groove formed in the pin 74. The button 72 and the pin 74 are integrally connected by the locking of the second connecting portion 742 of the pin 74 and the convex first connecting portion 721 of the button 72.

[0063] The restricting portion 744 is the enlarged part of the pin 74. The restricting portion 744 cannot enter the through hole 606 and restricts the pin 74 from moving upward from its predetermined position. As shown in Figure 5, when the button 72 is not pressed down, the pin 74 is positioned by the biasing force of the biasing member 76 to an initial position where the restricting portion 744 contacts the inner surface of the barrel 60.

[0064] The mating portion 78 is configured to be matable with the tip 746 of the pin 74. In this embodiment, the mating portion 78 is formed on the coupling 204. The mating portion 78 is a recess formed on the surface of the coupling 204. The shaft lock mechanism 70 is configured to fix the spindle 90 by locking the pin 74 with the coupling 204. In the die grinder 100 of this embodiment, by using the coupling 204 as part of the shaft lock mechanism 70, the provision of new members is avoided, thereby suppressing or preventing an increase in the number of parts of the die grinder 100. Furthermore, compared to the case where the members used in the shaft lock mechanism 70 are provided on the spindle 90 or the like, it is possible to prevent the length of the die grinder 100 in the front-to-back direction from becoming longer.

[0065] As shown in Figure 5, when the button 72 is not pressed down, the pin 74 is in its initial position. In the initial position, the mating portion 78 and the tip 746 of the pin 74 are not mated. When the user presses down the button 72 against the biasing force of the biasing member 76, the pin 74 moves to a position where its tip 746 mates with the mating portion 78 formed on the coupling 204 (hereinafter also referred to as the "matting position").

[0066] While button 72 is pressed down, the rotation of coupling 204 around the drive axis TX, i.e., the rotation of spindle 90 around the drive axis TX, is restricted by the engagement between pin 74 and mating portion 78. Therefore, while button 72 is pressed down, it is possible to prevent the collet nut 94 and spindle 90 from rotating together. The user can stop the rotation of spindle 90 by the simple method of pressing down button 72, and easily replace the tip tool TA.

[0067] A7. Length of die grinder 100 in the front-to-back direction: As shown in Figure 6, the die grinder 100 of this embodiment has a relatively short length in the front-to-back direction due to the configuration of the parts described above. The length of the main housing in the front-to-back direction of a typical die grinder is longer than 400 mm. "Length of the main housing 10" means the length from the rear end of the battery housing 80 to the front end of the tool housing 50 in the front-to-back direction. Note that the front end of the tool housing 50 does not include the collet cone 92, collet nut 94, and tip tool TA. The rear end of the battery housing 80 does not include the battery BT.

[0068] In contrast, in the die grinder 100 of this embodiment, the length LA of the main housing 10 in the front-to-back direction is 382.1 mm, which is 385 mm or less. In other words, the main housing of the die grinder 100 of this embodiment is shorter than that of a typical die grinder. According to the die grinder 100 of this embodiment, since the length in the front-to-back direction is relatively short, it can be used effectively even in confined spaces.

[0069] Furthermore, in the die grinder 100 of this embodiment, the length LB from the rear end of the battery housing 80 to the front end of the motor housing 30 in the front-rear direction of the main housing 10 is configured to be relatively short. In a typical die grinder, the length from the rear end of the battery housing 80 to the front end of the motor housing 30 in the front-rear direction is longer than 260 mm. In this embodiment, the front end of the motor housing 30 refers to the front end of the area where the motor housing 30 and the motor bearing retainer 32 come into contact. However, if the die grinder 100 does not have a motor bearing retainer 32, the front end of the motor housing 30 may be, for example, the front end of the motor shaft 22, or the front end of the area where the motor housing 30 and the tool housing 50 come into contact.

[0070] In contrast, in the die grinder 100 of this embodiment, the length LB from the rear end of the battery housing 80 to the front end of the motor housing 30 in the front-to-back direction is 246.5 mm. That is, the length from the rear end of the battery housing 80 to the front end of the motor housing 30 in the front-to-back direction is shorter than that of a typical die grinder. In the front-to-back direction, the rear half of the main housing 10 tends to be heavily loaded by the battery BT and motor 20 attached to the battery mounting section 86. In the die grinder 100 of this embodiment, the part of the main housing 10 that tends to be heavily loaded is relatively short, so the die grinder 100 can be carried in a balanced manner by gripping the gripping section 42. In addition, by gripping the gripping section 42, the user can easily operate the front half of the main housing 10 and perform machining work with the tip tool TA smoothly.

[0071] A8. Configuration of the gripping part 42: In the die grinder 100 of this embodiment, the gripping portion 42 has the following configuration.

[0072] (1) As shown in Figure 3, in the die grinder 100 of this embodiment, the central axis HX of the gripping portion 42 is located radially outward from the drive axis TX. In this embodiment, the drive axis TX is located above the drive axis TX. In the die grinder 100 of this embodiment, the central axis HX is substantially parallel to the drive axis TX and is located above the drive axis TX at any position of the gripping portion 42 in the front-rear direction. Note that, as shown in Figure 7, the central axis HX of the gripping portion 42 is located directly above the drive axis TX.

[0073] "The central axis HX of the gripping part 42" refers to a straight line based on the center of the cross-sectional shape of the gripping part 42. "The cross-sectional shape of the gripping part 42" refers to the outer shape of the gripping part 42 in a cross section perpendicular to the drive axis TX. "The center of the cross-sectional shape" includes the centroid or the center of gravity of the cross-sectional shape. In this embodiment, the center of gravity of the cross section of the gripping part 42 is defined as the center of the cross-sectional shape of the gripping part 42. In this embodiment, the straight line connecting the center of the cross-sectional shape of the gripping part 42 at the front end of the gripping part 42 and the center of the cross-sectional shape of the gripping part 42 at the rear end of the gripping part 42 is defined as the central axis HX of the gripping part 42. Alternatively, the centers of the cross-sectional shape of the gripping part 42 may be extracted at multiple locations, and a straight line derived from the extracted multiple centers using linear regression analysis or the like may be defined as the central axis HX of the gripping part 42.

[0074] In the die grinder 100, as described above, machining operations such as grinding and polishing can be performed by pressing the side TS of the tip tool TA against the workpiece. Therefore, when performing such machining operations, the user either tilts the die grinder 100 so that the front end is vertically lower than the motor housing 30, or tilts the die grinder 100 so that the front end is lower than the rear end, or moves the entire die grinder 100 downward toward the workpiece. In the die grinder 100 of this embodiment, the central axis HX of the gripping part 42 is positioned above the drive axis TX. Therefore, when the user grips the gripping part 42 with one hand and the tool housing 50 with the other hand to perform machining operations, the front end of the die grinder 100 can be easily tilted so that it is lower than the rear end. Thus, the workability of the die grinder 100 can be improved.

[0075] (2) The upper end of the gripping portion 42 is substantially flush with the upper end of the motor housing 30. This configuration allows the user to grip the gripping portion 42 comfortably. Furthermore, the user can easily operate the switch knob 34 provided on the motor housing 30 while gripping the gripping portion 42.

[0076] (3) The circumference of the gripping portion 42 is shorter than that of a typical die grinder. "Circumference of the gripping portion 42" refers to the length of the outer shape of the gripping portion 42 in a cross section perpendicular to the drive axis TX. Figure 7 schematically shows the circumference of the gripping portion 42 with a dashed line. In this disclosure, the circumference of the gripping portion 42 may also be referred to as the "thickness of the gripping portion 42". However, the circumference of the gripping portion 42 does not include parts that the user does not touch when gripping the gripping portion 42, or local irregularities that do not affect the function of the gripping portion 42, such as through holes, screw holes, grooves, decorations formed on the gripping portion 42.

[0077] In the die grinder 100 of this embodiment, the average circumference of the gripping portion 42 is 150 mm or less. That is, the gripping portion 42 is thinner than the gripping portion of a typical die grinder. Therefore, the user can grip the gripping portion 42 comfortably. In the die grinder 100 of this embodiment, the average circumference of the gripping portion 42 is approximately 146 mm.

[0078] (4) The length of the gripping portion 42 in the front-rear direction is longer than that of a typical die grinder. More specifically, in the die grinder 100 of this embodiment, the length of the gripping portion 42 in the front-rear direction is approximately 80 mm.

[0079] The length of the gripping portion 42 in the front-rear direction means the length from the front end of the gripping portion 42 to the rear end of the gripping portion 42. In this disclosure, "front end of the gripping portion 42" means the location at the front end of the handle housing 40 where the circumference of the gripping portion 42 is greater than or equal to a predetermined value than the average value of the circumference of the gripping portion 42. "Rear end of the gripping portion 42" means the location at the rear end of the handle housing 40 where the circumference of the gripping portion 42 is greater than or equal to a predetermined value than the average value of the circumference of the gripping portion 42.

[0080] In this embodiment, the front end of the gripping portion 42 is defined as the point at the front end of the handle housing 40 where the circumference of the gripping portion 42 exceeds 150 mm. In other words, the front end of the gripping portion 42 is set at a point where the circumference of the gripping portion 42 is approximately 3% larger than the average circumference of the gripping portion 42. Similarly, the rear end of the gripping portion 42 is defined as the point at the rear end of the handle housing 40 where the circumference of the gripping portion 42 exceeds 150 mm. In other words, the rear end of the gripping portion 42 is set at a point where the circumference of the gripping portion 42 is approximately 3% larger than the average circumference of the gripping portion 42.

[0081] In typical die grinders, the length of the gripping portion in the front-to-back direction is less than 60 mm. In the die grinder 100 of this embodiment, the length of the gripping portion 42 in the front-to-back direction is 80 mm, ensuring sufficient length. Therefore, the user can operate the die grinder 100 by gripping only the gripping portion 42, without gripping other parts of the main housing 10, such as the motor housing 30 or the battery housing 80. Thus, the user can grip the gripping portion 42 comfortably, improving the usability of the die grinder 100. Furthermore, the length of the gripping portion 42 is approximately 20% or more of the length LA of the main housing 10 in the front-to-back direction. In other words, the gripping portion 42 occupies a relatively wide area of ​​the main housing 10. In typical die grinders, the gripping portion is approximately 15% of the length LA of the main housing 10. In the die grinder 100 of this embodiment, the gripping portion 42 occupies a relatively large area of ​​the main housing 10, making it easy for the user to grip the gripping portion 42, and by gripping the gripping portion 42, the die grinder 100 can be carried in a balanced manner.

[0082] (5) The circumference of the gripping portion 42 in the front-rear direction is generally uniform. More specifically, the dimensional error of the circumference of the gripping portion 42 from the front end to the rear end is less than 3%. The uniform thickness of the gripping portion 42 allows the user to grip the gripping portion 42 comfortably.

[0083] As described above, according to the die grinder 100 of this embodiment, the battery mounting section 86 is positioned where the drive axis TX passes through, and the battery BT can be mounted in a direction perpendicular to the drive axis TX. The central axis HX of the gripping section 42 is positioned radially outward from the drive axis TX. Compared to the case where the battery BT is mounted in the battery mounting section 86 at an angle, the length of the battery housing 80 in the front-rear direction can be shortened. Therefore, while suppressing an increase in the length of the die grinder 100 in the front-rear direction, the length of the gripping section 42 in the front-rear direction can be extended by the amount by which the length of the battery housing 80 has been shortened. Thus, it is possible to provide a die grinder 100 that can suitably grip the gripping section 42 while suppressing an increase in size. Furthermore, since the central axis HX of the gripping portion 42 is positioned radially outward from the drive axis TX, the user can easily tilt the die grinder 100 so that the front end of the die grinder 100 is vertically lower than the rear end when operating the die grinder 100, thereby improving the workability of the die grinder 100.

[0084] In the die grinder 100 of this embodiment, the drive axis TX is configured to pass through the midpoint BC between the upper end BU of the battery BT attached to the battery mounting section 86 and the lower end BD of the battery BT when the die grinder 100 is viewed from the side. Therefore, the user can easily move the die grinder 100 along the drive axis TX and operate the die grinder 100 in a balanced manner. Thus, the workability of the die grinder 100 can be improved. In addition, it is possible to suppress or prevent the die grinder 100 from becoming larger radially outward from the drive axis TX.

[0085] In the die grinder 100 of this embodiment, the controller 84 is positioned so as to extend vertically when the die grinder 100 is viewed from the side, at a location through which the drive axis TX passes. Since the controller 84 is positioned on the drive axis TX, it is possible to suppress or prevent the main housing 10 from becoming larger in the radial direction. In addition, the length of the main housing 10 in the front-rear direction can be shortened compared to when the controller 84 is positioned at an angle to the drive axis TX.

[0086] In the die grinder 100 of this embodiment, the controller 84 is housed in the main housing 10 behind the gripping portion 42. By housing the controller 84 in the battery housing 80, which has more internal space compared to the motor housing 30 and handle housing 40, the controller 84 can be efficiently positioned within the main housing 10, thereby suppressing or preventing an increase in the size of the main housing 10.

[0087] In the die grinder 100 of this embodiment, the controller 84 is positioned so as to overlap at least a portion of the intake port 82 when the die grinder 100 is viewed from the side. This allows for air cooling of the controller 84 while shortening the length of the main housing 10 in the front-rear direction compared to when the controller 84 and the intake port 82 are positioned at different locations.

[0088] In the die grinder 100 of this embodiment, the length of the stator core 212C of the motor 20 in the front-rear direction is 30 mm or less. The motor 20 is configured to be relatively short in the front-rear direction. Therefore, the length of the gripping portion 42 in the front-rear direction can be extended while suppressing an increase in the length of the die grinder 100 in the front-rear direction.

[0089] The die grinder 100 of this embodiment is equipped with a shaft locking mechanism 70 that utilizes a coupling 204. By utilizing the coupling 204, it is possible to avoid providing a new component for the shaft locking mechanism 70. Therefore, it is possible to prevent an increase in the number of parts of the die grinder 100 and to prevent an increase in the length of the die grinder 100 in the front-to-back direction.

[0090] In the die grinder 100 of this embodiment, the switch 14 is housed in the gripping portion 42. Compared to the case where the switch 14 is housed in the motor housing 30 or the battery housing 80, this prevents the length of the die grinder 100 in the front-to-back direction from becoming longer.

[0091] In the die grinder 100 of this embodiment, the dial 88 is provided in the battery housing 80 located behind the gripping portion 42. By providing the dial 88 in the battery housing 80, which has more internal space compared to the motor housing 30 and handle housing 40, the dial 88 can be efficiently positioned in the main housing 10, thereby suppressing or preventing an increase in the size of the main housing 10.

[0092] In the die grinder 100 of this embodiment, the length of the gripping portion 42 in the front-rear direction is 80 mm, and the gripping portion 42 has sufficient length compared to the gripping portion of a typical die grinder. Therefore, the user can grip the gripping portion 42 comfortably, improving the usability of the die grinder 100.

[0093] In the die grinder 100 of this embodiment, the circumference of the gripping portion 42 is 146 mm, and the gripping portion 42 is thinner than the gripping portion of a typical die grinder. Therefore, the user can grip the gripping portion 42 comfortably, improving the usability of the die grinder 100.

[0094] In the die grinder 100 of this embodiment, the length LA of the main housing 10 in the front-to-back direction is 382.1 mm, which is shorter than the main housing of a typical die grinder. Therefore, since the length of the die grinder 100 in the front-to-back direction is relatively short, it can be used effectively even in confined spaces.

[0095] In the die grinder 100 of this embodiment, the length LB from the rear end of the battery housing 80 to the front end of the motor housing 30 in the front-rear direction is 246.5 mm, which is shorter than the length of a typical die grinder. Because the rear half of the main housing 10 is relatively short, the die grinder 100 can be operated in a balanced manner by gripping the gripping part 42.

[0096] B. Second Embodiment: As shown in Figure 8, the die grinder 100b according to the second embodiment differs from the die grinder 100 of the first embodiment in that it is equipped with a paddle switch 34b instead of a switch knob 34, but the other configurations are the same. Even with this configuration, the same effects as the first embodiment can be achieved.

[0097] The paddle switch 34b is located at the lower end of the gripping portion 42. The paddle switch 34b is biased outward from the gripping portion 42 by a coil spring 342 and is normally positioned in the stop position, which stops the motor 20. When a user pushes the paddle switch 34b inward against the biasing force of the coil spring 342, the paddle switch 34b is displaced to the start position, which starts the motor 20. Figure 8 shows the paddle switch 34b in the stop position.

[0098] Figure 8 schematically shows the outer surface 34S of the paddle switch 34b when it has been moved to the starting position. The outer surface 34S in the starting position is substantially flush with the lower end of the gripping portion 42. In the die grinder 100b configured in this way, when defining the circumference of the gripping portion 42, the outer surface 34S of the paddle switch 34b positioned in the starting position may be treated as part of the gripping portion 42.

[0099] The correspondence between each component (feature) of the above embodiments and each component (feature) of the present disclosure or invention is shown below. However, each component of the embodiments is merely an example and does not limit each component of the present disclosure or invention.

[0100] Die grinder 100 and die grinder 100b are examples of "die grinders". Motor 20 is an example of a "motor". Stator core 212C is an example of a "stator core". Stator 212, rotor 214, and motor shaft 22 are examples of "stator", "rotor", and "motor shaft". Motor rotation axis MX is an example of a "rotation axis of the motor shaft". Drive axis TX is an example of a "drive axis". Spindle 90 is an example of a "spindle". Main housing 10 is an example of a "main housing". Motor housing 30 is an example of a "motor housing". Handle housing 40 is an example of a "handle housing". Battery mounting section 86 is an example of a "battery mounting section". Battery housing 80 is an example of a "battery housing". Gripping section 42 is an example of a "gripping section". Controller 84 is an example of a "controller". Intake port 82 is an example of an "intake port". The shaft lock mechanism 70 is an example of a "shaft lock mechanism". The coupling 204 is an example of a "coupling". The switch knob 34 and paddle switch 34b are examples of a "first operating section". The switch 14 is an example of a "switch". The dial 88 is an example of a "second operating section".

[0101] Furthermore, the die grinders relating to this disclosure are not limited to the die grinders 100 and 100b of the embodiments described above. For example, modifications are possible, as are not limited to those described below. At least one of these modifications may be adopted in combination with the die grinders 100 and 100b of the embodiments and at least one of the features described in the claims.

[0102] (C1) In the first embodiment described above, an example was shown in which the die grinder 100 is equipped with a switch knob 34. In the second embodiment, an example was shown in which the die grinder 100b is equipped with a paddle switch 34b. In contrast, instead of the switch knob 34 and the paddle switch 34b, a trigger switch may be provided that allows the motor 20 to be started by a pull (or press) operation by the user. The trigger switch may be provided, for example, at the lower end of the gripping portion 42.

[0103] (C2) In the first embodiment described above, the drive axis TX is shown as being configured to pass through the midpoint BC between the upper end BU of the battery BT attached to the battery mounting section 86 and the lower end BD of the battery BT when the die grinder 100 is viewed from the side. In contrast, the drive axis TX may be configured to pass through the center of gravity of the battery BT attached to the battery mounting section 86. Alternatively, the drive axis TX may be configured to pass through the center (also called the centroid) of the outer shape of the battery BT in a cross section perpendicular to the drive axis TX. Even with this configuration, the user can easily move the die grinder 100 along the drive axis TX and operate the die grinder 100 in a balanced manner.

[0104] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of Symbols]

[0105] 10…Main housing, 14…Switch, 20…Motor, 21…Motor body, 22…Motor shaft, 26…Fan, 30…Motor housing, 32…Motor bearing retainer, 34…Switch knob, 34S…Exterior, 34b…Paddle switch, 40…Handle housing, 42…Grip section, 50…Tool housing, 58…Exhaust port, 60…Barrel, 66…Bearing retainer, 70…Shaft lock mechanism, 72…Button, 74…Pin, 76…Biasing member, 78…Matching section, 80…Battery housing, 82…Intake port, 84…Controller, 86…Battery mounting section, 88…Diamond 90...Spindle, 92...Collet cone, 94...Collet nut, 100, 100b...Die grinder, 201...Front bearing, 202...Rear bearing, 204...Coupling, 212...Stator, 212C...Stator core, 214...Rotor, 322...Opening, 342...Coil spring, 601...Front bearing, 602...Rear bearing, 604...Recess, 606...Through hole, 721...First connecting part, 724...Recess, 742...Second connecting part, 744...Regulating part, 746...Tip, BT...Battery, HX...Center axis, MX...Motor rotation axis, TA...Tip tool, TS...Side, TX...Drive axis

Claims

1. It is a die grinder, A motor powered by electricity supplied from a battery, The motor powers the spindle which rotates around a drive axis that defines the front-to-back direction of the die grinder, It is the main housing, A motor housing that houses the motor, A handle housing having an elongated gripping portion connected to the rear end of the motor housing and configured to be held by the user, A main housing including a battery housing connected to the rear end of the handle housing and having a battery mounting portion into which the battery can be mounted, The aforementioned battery mounting section is It is positioned at the location through which the aforementioned drive axis passes, The battery can be mounted in a direction perpendicular to the drive axis, The central axis of the gripping portion is positioned radially outward from the drive axis. Die grinder.

2. A die grinder according to claim 1, When the direction in which the battery is mounted in the battery mounting section is defined as the vertical direction, the drive axis is configured to pass through the midpoint between the upper end of the battery mounted in the battery mounting section and the lower end of the battery when the die grinder is viewed from the side. Die grinder.

3. A die grinder according to claim 1 or claim 2, Furthermore, it includes a controller configured to control the drive of the motor, The aforementioned controller, It is positioned at the location through which the aforementioned drive axis passes, When the die grinder is viewed from the side, it extends in a direction perpendicular to the drive axis, Die grinder.

4. A die grinder according to claim 3, The controller is housed in the main housing, rearward of the gripping portion. Die grinder.

5. A die grinder according to claim 3 or claim 4, The main housing is equipped with an intake port that allows external air to be introduced into the interior of the main housing. The controller is positioned such that, when the die grinder is viewed from the side, it overlaps with at least a portion of the intake port. Die grinder.

6. A die grinder according to any one of claims 1 to 5, The motor includes a stator including a stator core, a rotor, and a motor shaft that rotates together with the rotor. The motor is housed in the motor housing such that the rotation axis of the motor shaft is parallel to the front-rear direction. The length of the stator core in the front-rear direction is 30 mm or less. Die grinder.

7. A die grinder according to any one of claims 1 to 6, Furthermore, it is equipped with a shaft lock mechanism that can fix the spindle in a state where the rotation of the spindle has stopped. Die grinder.

8. A die grinder according to claim 7, Furthermore, a coupling is provided to connect the motor shaft and the spindle such that the rotation axis of the motor shaft and the drive axis are coaxial. The shaft lock mechanism is configured to fix the spindle by locking the shaft lock mechanism with the coupling. Die grinder.

9. A die grinder according to any one of claims 1 to 8, Furthermore, it is equipped with a switch that turns the motor on and off in response to the user's operation of the first control unit. The switch is housed in the gripping portion. Die grinder.

10. A die grinder according to any one of claims 1 to 9, The motor is equipped with a second operating unit that can adjust the rotation speed of the motor, The second operating section is provided behind the gripping section. Die grinder.

11. A die grinder according to any one of claims 1 to 10, In the aforementioned front-to-back direction, the length from the rear end to the front end of the gripping portion is 60 mm or more. Die grinder.

12. A die grinder according to any one of claims 1 to 10, In a cross-section perpendicular to the drive axis, the circumference of the gripping portion is 150 mm or less. Die grinder.

13. It is a die grinder, A motor powered by electricity supplied from a battery, A spindle is rotated by the power of the motor around a drive axis that defines the front-rear direction of the die grinder, It is the main housing, A motor housing that houses the motor, A handle housing having an elongated gripping portion connected to the rear end of the motor housing and configured to be held by the user, A tool housing connected to the front end of the motor housing, in which the spindle is located, A main housing including a battery housing connected to the rear end of the handle housing and having a battery mounting portion into which the battery can be mounted, In the aforementioned front-to-back direction, the length of the main housing from the rear end of the battery housing to the front end of the tool housing is 400 mm or less. Die grinder.

14. A die grinder according to claim 13, In the aforementioned front-to-back direction, the length of the main housing from the rear end of the battery housing to the front end of the motor housing is 260 mm or less. Die grinder.

15. A die grinder according to claim 13 or claim 14, In the aforementioned front-to-back direction, the length from the rear end to the front end of the gripping portion is 60 mm or more. Die grinder.

16. A die grinder according to any one of claims 13 to 15, In a cross-section perpendicular to the drive axis, the circumference of the gripping portion is 150 mm or less. Die grinder.

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