CIRCULAR SAW

Abstract

A circular saw includes a rotatable circular saw blade, an electric motor that generates rotational power to rotate the circular saw blade, and a battery mounting portion configured to removably mount a battery that supplies electrical power to the electric motor. The diameter of the circular saw blade is 300 mm or larger and 460 mm or smaller.

Description

TECHNICAL FIELD

[0001] The present invention relates to a circular saw. STATE OF THE ART

[0002] A cutting machine known as a portable circular saw (hereinafter simply referred to as a circular saw) includes a base and a main body portion. The main body portion includes a circular saw blade (circular saw blade) rotationally driven by an electric motor. The main body portion is disposed on one side relative to the base, and a portion (part) of the circular saw blade protrudes beyond the base on the other side, that is, a lower portion (part) of the circular saw blade protrudes through the base for cutting (sawing) workpieces. When using such a circular saw, a user brings a lower surface of the base into contact (application) with a workpiece in a state where the circular saw blade rotates, and moves the cutting machine forward. Thereby, the circular saw blade, which protrudes beyond (below) the base, cuts the workpiece.JP 2020 - 116 834 B2 discloses, as one type of such a circular saw, a portable circular saw that uses a battery as the electric power supply (power source) of the electric motor. SHORT SUMMARY

[0003] In the past, in a circular saw that uses a battery as an electric power supply, such as in JP 2020 - 116 834 B2, the diameter of the circular saw blade was relatively small (e.g., a diameter of 125 mm), and thus the cutting efficiency was poor, especially for thicker workpieces. This problem, which is not limited to portable circular saws, is common to circular saws that are used by being installed (mounted) in a fixed manner on a work stand. In view of the above, it is desirable to improve the cutting efficiency of circular saws that use a battery (battery pack) as the electric power supply (power source).

[0004] The above-mentioned problem is solved by a circular saw according to claim 1 or claim 17.

[0005] In one non-limiting aspect of the present teachings, a circular saw may include a rotatable circular saw blade (circular saw blade), an electric motor for providing rotational drive power to the circular saw blade, and a battery mounting portion configured to removably mount a battery for supplying electrical power to the electric motor. The diameter of the circular saw blade may be 300 mm or larger and 460 mm or smaller (i.e., from 300 to 460 mm).

[0006] According to this circular saw, since the diameter of the circular saw blade is 300 mm or larger and 460 mm or smaller, the curvature radius of the circular saw blade is large (the curvature is small), compared with conventional cordless (battery-powered) circular saws equipped with a small diameter circular saw blade. Accordingly, even when a workpiece has a large (thick) cross-section, cutting can be performed efficiently.

[0007] In another non-limiting aspect of the present teachings, a circular saw may include a rotatable circular saw blade, an electric motor for providing rotational drive power to the circular saw blade, a rotatable final output shaft on which the circular saw blade is mounted and to which the rotational drive power of the electric motor is transmitted, and a battery mounting portion configured to removably mount a battery for supplying electric power to the electric motor. When the torque of the final output shaft is 5 N / m, the value resulting from multiplying the peripheral speed of a blade edge of the circular saw blade by the diameter of the circular saw blade may be 6.0 m. 2 / s or larger.

[0008] According to this circular saw, even if the workpiece has a large (thick) cross section, the circular saw blade, which has a sufficient diameter, can cut the workpiece efficiently because it is rotated at a sufficient peripheral speed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a circular saw according to an embodiment of the present teachings. Fig. 2 is a perspective view of the circular saw. Fig. 3 is a perspective view of the circular saw with a battery removed. Fig. Figure 4 is a front view of the circular saw with some component parts removed. Fig. 5 is a left view showing a first example of dimensions of the circular saw. Fig. 6 is a plan view showing the first example of the dimensions of the circular saw. Fig. Figure 7 is a left view showing a second example of the dimensions of the circular saw. Fig. 8 is a plan view showing the second example of the dimensions of the circular saw. Fig. 9 is a left view showing a third example of the dimensions of the circular saw. Fig. 10 is a plan view showing the third example of the dimensions of the circular saw. Fig. 11 is a left view of the circular saw according to a second embodiment. Fig. 12 is a right view of the circular saw according to the second embodiment. Fig. 13 is a plan view of the circular saw according to the second embodiment. Fig. 14 is a bottom view of the circular saw according to the second embodiment. Fig. 15 is a front view of the circular saw according to the second embodiment. Fig. 16 is a rear view of the circular saw according to the second embodiment. Fig. Figure 17 is a graph showing the relationship between the torque of a final output shaft and the product of the peripheral speed of a blade edge and a diameter of a circular saw blade. Fig. 18 is a plan view of the circular saw according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Representative and non-limiting specific examples of the present teachings are explained in detail below with reference to the drawings. This detailed description is merely intended to disclose to those skilled in the art details for implementing preferred embodiments of the present teachings and is not intended to limit the scope of the present invention. Furthermore, additional features and inventions disclosed below may be used separately or in conjunction with other features or inventions to provide further improved devices, and methods of making and using the same.

[0010] Furthermore, combinations of features or methods disclosed in the detailed description below are not required in the practice of the present invention to the fullest extent possible and are described only to illustrate representative specific examples of the present invention. Furthermore, in providing additional useful embodiments of the present invention, various features of the representative specific examples mentioned above and below, as well as various features described in the independent and dependent claims, need not be combined as described in the specific examples listed herein or in the order listed.

[0011] Regardless of the configurations of the features described in the embodiments and / or the claims, all features described in the present specification and / or claims are intended to be disclosed individually and independently of one another as limitations on the specific matters disclosed and claimed at the time of filing. Furthermore, the descriptions of all numerical ranges and groupings or categories are intended to disclose all intermediate configurations thereof as limitations on the specific matters disclosed and claimed at the time of filing.

[0012] In one or more embodiments, a circular saw may be configured such that the circular saw blade rotates at a peripheral speed of 70.0 m / s or less under no load. According to this configuration, the difference between the peripheral speeds of the circular saw blade under no load (idle operation) and under load can be made relatively small. Accordingly, the behavior of the circular saw when it starts cutting the tool is stable. Consequently, the user experience can be improved, and the cutting surface of the workpiece can also be made smoother (more uniform, flatter).

[0013] In one or more embodiments, the circular saw may be configured such that the circular saw blade rotates at a peripheral speed of 50.0 m / s or less under no-load (idle) conditions. According to this configuration, the difference between the peripheral speeds of the circular saw blade under no-load and under load conditions can be made relatively small. Accordingly, the behavior of the circular saw is even more stable when it begins cutting the workpiece.

[0014] In one or more embodiments, the circular saw may be configured such that the circular saw blade rotates at a peripheral speed of 25.0 m / s or less under load. According to this configuration, even when the workpiece has a large (thick) cross-section, cutting can be performed efficiently at a sufficient peripheral speed.

[0015] In one or more embodiments, the circular saw may be configured such that the circular saw blade rotates at a peripheral speed of 28.0 m / s or greater under load. According to this configuration, the workpiece may be cut more efficiently.

[0016] In one or more embodiments, the circular saw may be configured to rotate such that the force at a blade edge of the circular saw blade under a load of 20.0 N or greater. The "blade edge force" is the force that the blade edge applies to the cutting location of the workpiece. According to this configuration, even when the workpiece has a large (thick) cross-section, the workpiece can be cut efficiently because a sufficient cutting force is applied to the workpiece.

[0017] In one or more embodiments, the circular saw may be configured to rotate such that the force at the blade edge of the circular saw blade under a load is 30.0 N or greater. According to this configuration, the workpiece may be cut more efficiently.

[0018] In one or more embodiments, the circular saw may include a battery (battery pack) that supplies electrical power to drive the electric motor. The rated voltage of the battery may be 18 V or greater and 80 V or less. According to this configuration, even when the workpiece has a large (thick) cross-section, the workpiece can be cut efficiently due to the sufficient battery output.

[0019] In one or more embodiments, the nominal voltage of the battery may be 36 V. According to this configuration, the circular saw may be designed to be both compact (and, for example, lightweight) and capable of delivering high power with a satisfactory balance.

[0020] In one or more embodiments, the circular saw may include a speed reduction mechanism configured to transmit the rotary drive power of the electric motor to the circular saw blade at a lower speed. The speed reduction ratio (also known as a "speed ratio" or "angular velocity ratio") of the speed reduction mechanism may be 7 or greater (or alternatively expressed as 7:1 or greater). According to this configuration, even if the workpiece has a large (thick) cross-section, the workpiece can be cut efficiently because the speed reduction mechanism supplies sufficient torque to the circular saw blade.

[0021] In one or more embodiments, the circular saw may be a portable circular saw. The portable circular saw may include a first handle having a first grip portion, and a second handle having a second grip portion and disposed further forward than the first handle when the direction in which cutting advances by the portable circular saw is defined as a front side (front side) and the opposite side to the front side is defined as a rear side (rear side). The battery mounting portion may be configured such that, when the battery is mounted to the battery mounting portion, the entire battery is located between an end portion at the front of the first grip portion and an end portion at the front of the second grip portion in a front-to-rear direction.According to this configuration, since the battery, which is a heavy object, is located between the end portion at the front of the first handle part and the end portion at the front of the second handle part, the weight balance is improved when the user grips the first handle part and the second handle part and holds the portable circular saw, regardless of whether the portable circular saw has a large-diameter circular saw blade (e.g., a circular saw blade with a diameter of 300 mm or larger). Accordingly, the user can hold the portable circular saw stably with a smaller force; that is, it is less tiring (burdensome) to operate the circular saw.

[0022] In one or more embodiments, the circular saw may be a portable circular saw. The portable circular saw may include a first handle having a first grip portion, and a second handle having a second grip portion and disposed further forward than the first handle when the direction in which cutting advances (is advanced) by the portable circular saw is defined as the front side, and the opposite side to the front side is defined as the rear side. The center of gravity of the circular saw in the state in which the battery is mounted to the battery mounting portion may be located further downward than an end portion on the lower side of the first grip portion and an end portion on the lower side of the second grip portion in the up-down direction in the posture of the portable circular saw during normal use thereof.According to this configuration, the user can hold the portable circular saw stably with a smaller force when the user grasps the first handle part and the second handle part and holds the portable circular saw.

[0023] In one or more embodiments, the circular saw may be a portable circular saw. The portable circular saw may include a first handle having a first grip portion, and a second handle having a second grip portion and disposed further forward than the first handle when the direction in which cutting of the portable circular saw advances is defined as the front side, and the opposite side to the front side is defined as the rear side; and the battery (i.e., rechargeable battery pack or cartridge). The center of gravity of the battery in the state where the battery is mounted to the battery mounting portion may be located further downward than an end portion on the lower side of the first grip portion and an end portion on the lower side of the second grip portion in an up-down direction in the posture of the portable circular saw during normal use thereof.Since the center of gravity of the battery, which is a heavy object, is located further down than the handle parts, that is, the first handle part and the second handle part, when the user grips the first handle part and the second handle part and holds the portable circular saw, the user can hold the portable circular saw stably with a smaller force.

[0024] In one or more embodiments, the portable circular saw may be a portable circular saw. The portable circular saw may include a first handle having a first grip portion and a second handle having a second grip portion and disposed further forward than the first grip portion when the direction in which cutting advances by the portable circular saw is defined as the front side and the opposite side to the front side is defined as the rear side.In the front-to-back direction, when a distance between a first center point of the first handle part, which is the center point of a range where the user actually grips the first handle part, and a second center point, which is the center point of the second handle part, is given as L1, and a distance between the first center point and a first center of gravity, which is the center of gravity of the circular saw in the state where the battery is mounted to the battery mounting part, is given as L2, the value of L2 / L1 can be 0.5 or greater and 0.7 or less. According to this configuration, the weight balance is improved when the user grips the first handle part and the second handle part and holds the portable circular saw, regardless of whether the portable circular saw has a large-diameter circular saw blade (e.g., a circular saw blade with a diameter of 300 mm or larger).Accordingly, the user can hold the portable circular saw stably with less force.

[0025] In one or more embodiments, in the up-down direction in the posture of the portable circular saw during normal use thereof, when a distance between the first center point of the first handle part, which is the center point of a range where the user actually grips the first handle part, and the second center point, which is the center point of the second handle part, is given as L3, and a distance between the first center point and the first center of gravity, which is the center of gravity of the circular saw in the state where the battery is mounted to the battery mounting part, is given as L4, the value of L4 / L3 may be 3.4 or greater and 3.8 or less. According to this configuration, the weight balance for the user is improved when the user grips the first handle part and the second handle part and holds the portable circular saw.

[0026] In one or more embodiments, in the front-to-back direction, when a distance between the first center point of the first grip part, which is the center point of a range where the user actually grips the first grip part, and the second center point, which is the center point of the second grip part, is given as L1, and the distance between the first center point and a second center of gravity, which is the center of gravity of the battery in the state where the battery is mounted to the battery mounting part, is given as L5, the value of L5 / L1 may be 0.1 or greater and 0.3 or less. According to this configuration, the weight balance for the user is improved when the user grips the first grip part and the second grip part and holds the portable circular saw.

[0027] In one or more embodiments, in the up-down direction in the posture of the portable circular saw during normal use thereof, when a distance between the first center point of the first handle part, which is the center point of a range where the user actually grips the first handle part, and the second center point, which is the center point of the second handle part, is given as L3, and a distance between the first center point and the second center of gravity, which is the center of gravity of the battery in the state where the battery is mounted to the battery mounting part, is given as L6, the value of L6 / L3 may be 2.8 or greater and 3.2 or less. According to this configuration, the weight balance for the user is improved when the user grips the first handle part and the second handle part and holds the portable circular saw.

[0028] In one or more embodiments, in an axial direction, which is the direction in which the rotational axis of the circular saw blade extends, when a distance between the first center point of the first grip part, which is the center point of a range where the user actually grips the first grip part, and the second center point, which is the center point of the second grip part, is given as L7, and a distance between the first center point and the first center of gravity, which is the center of gravity of the circular saw in the state where the battery is mounted to the battery mounting part, is given as L8, the value of L8 / L7 may be 0.4 or greater and 0.7 or less. According to this configuration, the weight balance for the user is improved when the user grips the first grip part and the second grip part and holds the portable circular saw.

[0029] In one or more embodiments, in the axial direction, which is the direction in which the rotational axis of the circular saw blade extends, when a distance between the first center point of the first grip part, which is the center point of a range where the user actually grips the first grip part, and the second center point, which is the center point of the second grip part, is given as L7, and a distance between the first center point and the second center of gravity, which is the center of gravity of the battery in the state where the battery is mounted to the battery mounting part, is given as L9, the value of L9 / L7 may be 1.3 or greater and 1.5 or less. According to this configuration, the weight balance for the user is improved when the user grips the first grip part and the second grip part and holds the portable circular saw.

[0030] In one or more embodiments, the circular saw may be a portable circular saw and may include a base having a through hole (slot) through which the circular saw blade can pass. When the side on which the electric motor is located relative to the base is defined as the upper side, and the opposite side thereto is defined as the lower side, the circular saw blade is perpendicular to the base, and in the state where a protrusion distance by which the circular saw blade passes through the through hole and protrudes downward relative to the base (i.e., the extent to which the circular saw blade extends below the base) becomes a maximum, the protrusion distance may be 100 mm or greater (i.e., 100 mm or greater of the circular saw blade (i.e., the distance from the rotation center of the circular saw blade to the peripheral edge thereof) can protrude below the base).According to this configuration, workpieces with a greater thickness can be cut compared to existing circular saws.

[0031] In one or more embodiments, in the state where the circular saw blade is perpendicular to the base and the protrusion distance by which the circular saw blade passes through the through hole and protrudes downward relative to the base (ie, the extent to which the circular saw blade extends below the base) becomes maximum, the protrusion distance at the lower side of the circular saw blade may be 150 mm or more (ie, 150 mm or more of the circular saw blade (ie, the distance from the rotation center of the circular saw blade to the peripheral side thereof) may protrude below the base). According to this configuration, a workpiece having an even greater thickness can be cut.

[0032] If the torque of the final output shaft is 5 N / m, the value obtained by multiplying the peripheral speed of the blade edge of the circular saw blade by the diameter of the circular saw blade can be 10.0 m 2 / s or greater. According to this configuration, a circular saw blade with a sufficient diameter can cut the workpiece more efficiently because it rotates at a sufficient peripheral speed for cutting even relatively thick workpieces.

[0033] In one or more embodiments, the circular saw may be a portable circular saw and may include a base having a through hole (slot) through which the circular saw blade may pass.If the side to which the circular saw blade advances when the circular saw cuts a workpiece is defined as the front side, the opposite side thereof is defined as the rear side thereof, the side on which the electric motor is located relative to the base is defined as the upper side, and the opposite side thereof is defined as a lower side, a direction perpendicular to the front-rear direction and an up-down direction is defined as a left-right direction, and the right side when viewed from the rear side to the front side is defined as the right side, and the opposite side thereof is defined as the left side, the circular saw blade may be located on the left side relative to the electric motor.According to this configuration, when a user operates the circular saw while standing on the left side of the circular saw, the electric motor is not positioned in the user's line of sight to the circular saw blade. Therefore, when the user performs work using the circular saw, the visibility of the circular saw blade visible between a front portion of a fixed cover and a front portion of the base can be improved, especially on a side where the circular saw blade intersects (cuts) with a marking line on the workpiece.

[0034] In one or more embodiments, the circular saw may include a first handle having a first grip portion located at least partially further rearward than the circular saw blade in the front-to-back direction, a second handle having a second grip portion located further forward than the electric motor in the front-to-back direction and further to the right than the circular saw blade in the left-to-right direction, and a third handle having a third grip portion located further to the left than the circular saw blade in the left-to-right direction. According to this configuration, the user can select different handles to grip according to the user's working posture for use. For example, the user may grip the first handle portion with one hand and the second handle portion with the other to use the circular saw.Alternatively, the user can grip the first handle with one hand and the third handle with the other hand to operate the circular saw. Furthermore, since the distance in the front-to-back direction between the first handle and the second handle can be made relatively large, the user can hold the circular saw more stably when gripping the first handle and the second handle to operate the circular saw.

[0035] In one or more embodiments, the third handle portion may be located farther forward than the electric motor in the front-to-back direction. According to this configuration, since the distance in the front-to-back direction between the first handle portion and the third handle portion can be made larger, the user can hold the circular saw more stably when the user grasps the first handle portion with one hand and the third handle portion with the other hand to use the circular saw.

[0036] A portable circular saw (hereinafter simply referred to as a circular saw) 10 according to an exemplary embodiment will be described in detail with reference to Fig. 1 to 6. In the following description, when the user holds the circular saw 10 with two hands to cut (sawing) a workpiece (in other words, when the circular saw 10 is in the normal posture for a cutting (sawing) operation), the side to which the circular saw 10 is advanced (the side to which cutting advances by a circular saw blade (circular saw blade) 35 as described below) is defined as the front side (front side) of the circular saw 10, and the opposite side thereof is defined as the rear side (rear side) of the circular saw 10. Further, at this time, the side located in the vertically upward direction is defined as the upper side of the circular saw 10, and the opposite side is defined as the lower side of the circular saw 10.Furthermore, a left-right direction is defined as the direction perpendicular to the front-back direction and the up-down direction. The right side of the circular saw 10 in the left-right direction is defined as the right side when the circular saw 10 is viewed from the back to the front, and the opposite side is defined as the left side of the circular saw 10.

[0037] As in Fig. 1, the circular saw 10 includes a base 20 and a main body portion 30. The base 20 has a substantially rectangular outer shape. The longitudinal direction of the base 20 is the front-to-back direction. The base 20 has a flat bottom surface that is abutted (brought into contact) against the workpiece when the workpiece is cut.

[0038] As in Fig. 1, the main body portion 30 is principally arranged upwards from the base 20. As shown in Fig. 1 to 4, the main body portion 30 includes a motor housing 11, a gear housing 12, a first handle 50, a second handle 60, an electric motor 41, the circular saw blade 35, a fixed cover 33, and a movable cover 34.

[0039] A portion of the circular saw blade 35 passes through a through hole (slot) 21 in the base 20 and projects downward through (under) the base. The circular saw blade 35 may be a toothed (tipped) saw blade (e.g., carbide-tipped, cermide-tipped, diamond-tipped, etc.) and has a substantially circular shape. The circular saw blade 35 is configured to rotate around a rotation axis AX extending in the left-right direction as the center by a rotational drive power provided by the electric motor 41 (see Fig. 4) is provided (dispensed). The fixed cover 33 covers an upper portion of the circular saw blade 35 and has an arc shape. The movable cover 34 covers a portion of the circular saw blade 35 located below the fixed cover 33. The movable cover 34 is configured to be retractable along an outer peripheral edge portion of the circular saw blade 35 and is normally rotated toward the position shown in Fig. 1, by a biasing member (not shown). When the circular saw 10 is in use, the movable cover 34 is pressed against the workpiece and is retracted rearward, thereby exposing the portion of the circular saw blade 35 located downward (below) the base 20.

[0040] As in Fig. 2 and Fig. 3, the motor housing 11 is arranged on the left side of the fixed cover 33. The electric motor 41, which is intended to provide a rotational drive power for the circular saw blade 35, is accommodated in the interior of the motor housing 11. A battery mounting part 13 (see Fig. 3) is formed at a rear end portion of the motor housing 11 and is configured to removably mount a battery (see Fig. 2), which supplies electrical power to the electric motor 41. The battery 14 may be, for example, a known rechargeable battery pack or a battery cartridge containing, for example, lithium-ion battery cells or solid-state batteries. The battery mounting part 13 has electrical terminals for electrically connecting to the battery 14 and guide grooves that fit with convex portions (slide rails) of the battery 14. In the present embodiment, the battery mounting part 13 is configured such that the battery 14 can be mounted by sliding the battery 14 from top to bottom along the guide grooves. As shown in Fig. 2, by mounting the battery 14 so that the longitudinal direction of the battery 14 coincides with the up-down direction, the center of gravity of the battery 14 can be positioned further toward the front when the battery 14 is mounted, compared with other configurations.

[0041] As in Fig. 3, the gear case 12 is arranged between the fixed cover 33 and the motor housing 11 in the left-right direction. A mechanical mechanism (e.g., a speed reduction mechanism 43 and a spindle 46, etc., which will be described later) for transmitting the rotational drive power of the electric motor 41 to the circular saw blade 35 is housed inside the gear case 12. As shown in Fig. 4, a motor shaft 42 of the electric motor 41 extends in the left-right direction, which is also referred to as the axial direction or rotation axis direction. Further, below the motor shaft 42, the spindle 46 extends parallel to the motor shaft 42. The spindle 46 extends from the inside of the gear case 12 toward the right side, passing through a right surface of the gear case 12 and a left surface of the fixed cover 33, and the circular saw blade 35 is mounted to the tip (front end) thereof using a fixing device (holder) 36 such as an outer flange and a hex bolt. The circular saw blade 35 extends perpendicularly to the bottom surface of the base 20.

[0042] As in Fig. 4, the motor shaft 42 is operatively coupled to the spindle 46 via the speed reduction mechanism 43. The speed reduction mechanism 43 includes a drive gear 44 mounted around the motor shaft 42 and a driven gear 45 mounted around the spindle 46. The speed reduction mechanism 43 reduces the rotational input speed of the rotor of the electric motor 41 by a speed ratio defined based on the gear ratio between the drive gear 44 and the driven gear 45, and transmits the rotational input power (a speed lower than the rotor speed but with a higher torque) to the spindle 46 and, in turn, to the circular saw blade 35.

[0043] As in Fig. 2 and Fig. 3, the first handle 50 is formed as a loop-shaped handle. The first handle 50 extends in a tubular shape along the arcuate shape of the fixed cover 33, so that a gap (gripping space) is formed between the fixed cover 33 and the first handle 50 along an upper end portion at the rear of the fixed cover 33. Accordingly, a first grip portion 51, which can be gripped by inserting fingers into the gripping space, is formed on the first handle 50. The first grip portion 51 is a portion extending in a circular tubular shape with a substantially constant diameter and is intended to be gripped by the user's hand when the circular saw 10 is used. A switching lever 55 for starting and stopping the electric motor 41 is provided at a front end portion on the upper side of the first grip portion 51.Accordingly, the user will grasp the first grip portion 51 with one hand (usually the right hand) at a location offset from the upper side of the first grip portion 51 so that one finger (usually the index finger) can reach the shift lever 55.

[0044] As in Fig. 2 and Fig. 3, a second handle 60 is arranged further forward than the first handle 50. In the present embodiment, the second handle 60 is formed as a loop-shaped handle. However, it may also be formed as a rod-shaped handle that extends linearly (straight) to the left from the left surface of the fixed cover 33. The second handle 60 extends in a tubular shape so that it spans (extends) from a portion of the left surface of the fixed cover 33, which is further forward than the electric motor 41, to an upper end portion at the front of the motor housing 11.The portion of the second handle 60 extending in the left-right direction with a substantially constant diameter functions as a second grip portion 61 intended for the user to be gripped with one hand (normally the left hand) when using the circular saw 10.

[0045] When using the circular saw 10, the user grasps the first grip portion 51 of the first handle 50 with one hand (usually the right) and the second grip portion 61 of the second handle 60 with the other hand (usually the left) and lifts the circular saw 10. When the user presses the switch lever 55, the circular saw blade 35 rotates under the rotational drive power of the electric motor 41. In this state, the user brings the lower surface of the base 20 (the area further forward than the circular saw blade 35) into contact (application) with the workpiece, and moves the circular saw 10 forward by sliding the base 20 along the surface of the workpiece. Consequently, the cutting of the workpiece by the circular saw blade 35, which projects downward beyond (below) the lower surface of the base 20, proceeds in the direction in which the circular saw 10 moves.

[0046] As in Fig. 1 and Fig. 2, an angle plate 22 and a fixing lever 23 are mounted on the front end portion. A bracket 24, which has a two-leg shape, is mounted on a rear surface of the angle plate 22. As shown in Fig. 1, a pivot shaft 25 is supported by the bracket 24 in a state where the pivot shaft 25 passes through the two legs of the bracket 24 and the front end portion of the fixed cover 33 disposed between the two legs of the bracket 24. Due to such a configuration, the front side of the main body portion 30 is supported by the pivot shaft 25 so as to be pivotable relative to the base 20 around the pivot shaft 25 to change the cutting depth of the circular saw blade 35.

[0047] In this regard, the back (rear side) of the main body portion 30 is supported by a depth guide 26. The pivot position (i.e., cutting depth) of the main body portion 30 (the circular saw blade 35) relative to the base 20 is adjustable by the depth guide 26 and a fixing lever 27. This type of structure is known, and an explanation will be omitted here.

[0048] Furthermore, the main body portion 30 (the circular saw blade 35) is also configured to be tiltable relative to the base 20 about a tilt axis extending in the front-back direction. Due to this configuration, for example, the workpiece can be cut diagonally (obliquely); that is, a miter cut can be performed. Such a tilting operation is performed by using the angle plate 22 and the fixing lever 23. Since the structures for tilting (miter cuts) in which the angle plate 22 is used are known, a description thereof will be omitted.

[0049] In the circular saw 10 described above, a circular saw blade having a diameter of 300 mm or larger and 460 mm or smaller is used as the circular saw blade 35. According to this configuration, the radius of curvature of the circular saw blade 35 is large compared with known battery-type circular saws equipped with a smaller diameter circular saw blade (for example, a diameter of 125 mm). Accordingly, even if the workpiece has a large cross section, the workpiece can be cut efficiently. The diameter of the circular saw blade 35 can be 360 ​​mm or larger and 460 mm or smaller. When configured in this way, cutting efficiency can be further improved. A 415 mm circular saw blade is disclosed as a specific example in the present embodiment.

[0050] Furthermore, the circular saw 10 may be configured such that the circular saw blade 35 rotates at a peripheral speed of 25.0 m / s or greater under load (i.e., while the circular saw 10 is cutting a workpiece). According to this configuration, even when the workpiece has a large cross-section, cutting can be performed efficiently at a sufficient peripheral speed. The peripheral rotation speed under load may be 28.0 m / s or greater. When configured in this way, cutting efficiency can be further improved. A peripheral speed of 29.7 m / s under load is disclosed as a specific example in the present embodiment.

[0051] Furthermore, the circular saw 10 can be configured such that the circular saw blade 35 rotates at a peripheral speed of 70.0 m / s or less under no-load (idle) conditions (i.e., the circular saw blade 35 rotates freely while not cutting a workpiece). According to this configuration, the difference between the peripheral speeds of the circular saw blade 35 under load and under no-load conditions can be made relatively small. Accordingly, the behavior of the circular saw 10 when it starts cutting the workpiece is stable. As a result, the user experience can be improved, and the cutting surface of the workpiece can be made smoother (more uniform). The peripheral speed under no-load conditions can be 50.0 m / s or less. When configured in this way, the difference between the peripheral speeds of the circular saw blade 35 under no-load conditions and under load conditions can also be made smaller.A peripheral speed of 45.6 m / s under no load is disclosed as a specific example in the present embodiment.

[0052] Furthermore, the circular saw 10 may be configured to rotate such that the force at the blade edge of the circular saw blade 35 under a load is 20.0 N or greater. According to this configuration, even when the workpiece has a large (thick) cross section, the workpiece can be cut efficiently because a sufficient force acts on the workpiece. The force at the blade edge of the circular saw blade 35 under a load may be 30.0 N or greater. According to this configuration, the workpiece can be cut more efficiently. The blade edge force under a load of 40.5 N is disclosed as a specific example in the present embodiment.

[0053] Furthermore, a battery having a rated voltage of 18 V or greater and 80 V or less can be used as the battery 14. According to this configuration, even if the workpiece has a large (thick) cross-section, the workpiece can be cut efficiently due to the sufficient battery output. The rated voltage of the battery 14 can be, for example, from 24 to 40 V, such as 36 V. When configured in this manner, the circular saw 10 can be designed to be both compact (e.g., lightweight) and capable of high output with a satisfactory balance.

[0054] Furthermore, the speed reduction ratio of the speed reduction mechanism 43 can be set at 7 or greater. According to this configuration, even if the workpiece has a large (thick) cross section, the workpiece can be cut efficiently because the circular saw 10 generates sufficient torque.

[0055] Various exemplary features will be described below regarding the configuration (construction) of the circular saw 10. The following description refers to features in the state in which the cutting depth of the circular saw blade 35 is set to a maximum value (maximum depth) by the depth guide 26, and the circular saw blade 35, when viewed in the front-to-back direction, is fixed by the angle plate 22 so as to be parallel to the vertical direction (i.e., the circular saw blade 35 is perpendicular to the base 20).However, the circular saw 10 may be configured such that the various features described below can also be applied when the cutting depth of the circular saw blade 35 is set to any value between a minimum value (minimum depth) and the maximum value (maximum depth), and when the circular saw blade 35, when viewed in the front-to-back direction, is angled at any angle (bevel angle / miter angle) relative to the vertical direction. Alternatively, the circular saw 10 may be configured such that at least one of the various features described below can be applied when the cutting depth of the circular saw blade 35 is set to a specific value between the minimum value and the maximum value, and / or when the circular saw blade 35, when viewed in the front-to-back direction, is angled (inclined) at a specific angle relative to the vertical direction.

[0056] In the present embodiment, as shown in Fig. 5 and Fig. 6, in the state in which the battery 14 is mounted on the battery mounting part 13, the battery 14 is located in the front-back direction between a front end portion 52 of the first grip part 51 of the first handle 50 and a front end portion 62 of the second grip part 61 of the second handle 60. Here, the front end portion 52 is the portion of a first half portion 54 (indicated by hatching in Fig. 3) which is located most rearward. The first half portion 54 is the portion (half of the outer peripheral surface of the tubular body located on the side close to the rotation axis AX) of the half portion in the circumferential direction of the first handle part 51—which is a tubular body having a substantially constant diameter—that faces (is directed toward) the rotation axis AX of the circular saw blade 35. In Fig. 3 only the left-hand half of the first half region 54 is visible. Furthermore, the front end region 62 is the foremost region of the second half region 64 (indicated by hatching in Fig. 3). The second half portion 64 is the portion of the half portion in the circumferential direction of the second handle part 61—which is a tubular body having a substantially constant diameter—that faces the rotational axis AX of the circular saw blade 35 (the half of the outer peripheral surface of the tubular body that is on the side near the rotational axis AX). Fig. 3 only a back half of the second half area 64 is visible.

[0057] If the diameter of the circular saw blade 35 is made large, as in the present embodiment, not only would the weight of the circular saw blade 35 increase, but the battery 14, which is a heavy object, would also be required to have a higher power output. Accordingly, in embodiments in which an arrangement identical to that of known circular saws using a small-diameter circular saw blade were adopted, the weight balance would be poor when the user grips the first handle part 51 and the second handle part 61 and holds the circular saw 10. However, according to the arrangement described above, since the battery 14, which is a heavy object, is located between the front end portion 52 of the first handle part 51 and the front end portion 62 of the second handle part 61 (ie,Between the rearmost portion of the first grip portion 51 and the frontmost portion of the second grip portion 61, which are the portions intended to be gripped by the user's hands), the weight balance is improved when the user grips the first grip portion 51 and the second grip portion 61 and holds the circular saw 10, even if the diameter of the circular saw blade 35 is made large. Accordingly, the user can hold the circular saw blade 35 stably with less force.

[0058] Furthermore, in the present embodiment, as shown in Fig. 5, the center of gravity 15 of the circular saw 10 in the state in which the battery 14 has been mounted to the battery mounting part 13 (ie, the center of gravity in the state in which the battery 14 is mounted) is downward from the end portion on the lower side of the first handle part 51 and the end portion on the lower side of the second handle part 61 in the up-down direction. By adopting such an arrangement, the weight balance for the user is improved when the user grips the first handle part 51 and the second handle part 61 and holds the circular saw 10.

[0059] In addition, as in Fig. 5, in the present embodiment, the center of gravity 16 of the battery 14, which is a heavy object, is located downward from the end portion on the lower side of the first grip portion 51 and the end portion on the lower side of the second grip portion 61 in the up-down direction in the state where the battery 14 is mounted on the battery mounting part 13. By adopting this type of arrangement, the weight balance for the user is improved when the user grips the first grip portion 51 and the second grip portion 61 and holds the circular saw 10.

[0060] Furthermore, in the present embodiment, the first handle portion 51, the second handle portion 61, the center of gravity 15 of the circular saw 10, and the center of gravity 16 of the battery 14 are arranged to satisfy the conditions described below. Specifically, as first described in Fig. 5 and Fig. 6, a first center point 53 is defined as the center point of a region of the first grip part 51 at which the user actually grips the first grip part 51. Further, a second center point 63 is defined as the center point of the second grip part 61. In reality, when gripping the first grip part 51, the user grips the first grip part 51 at a position at which a finger of the hand gripping the first grip part 51 reaches the shift lever 55 (i.e., at a position of the first grip part 51 that is in the vicinity of the end portion on the front side of the first grip part 51). The first center point 53 is a center point determined by focusing only on the region at which the user actually grips the first grip part 51 at that time.

[0061] In addition, as in Fig. 5, distance L1 is defined as the distance between the first center point 53 and the second center point 63 in the front-to-back direction, and distance L2 is defined as the distance between the first center point 53 and the first center of gravity 15 of the circular saw 10 in the front-to-back direction. In addition, as shown in Fig. 5, the distance L3 is defined as the distance between the first center point 53 and the second center point 63 in the up-down direction, and the distance L4 is defined as the distance between the first center point 53 and the center of gravity 15 of the circular saw 10 in the up-down direction. In addition, as shown in Fig. 5, the distance L5 is defined as the distance between the first center point 53 and the center of gravity 16 of the battery 14 in the front-back direction, and the distance L6 is defined as the distance between the first center point 53 and the center of gravity 16 of the battery 14 in the up-down direction.

[0062] In addition, as in Fig. 6, the distance L7 is defined as the distance between the first center point 53 and the second center point 63 in the left-right direction (ie, the direction in which the rotational axis AX of the circular saw blade 35 extends), the distance L8 is defined as the distance between the first center point 53 and the center of gravity 15 of the circular saw 10 in the left-right direction, and the distance L9 is defined as the distance between the first center point 53 and the center of gravity 16 of the battery 14 in the left-right direction.

[0063] In this case, a first example, a second example and a third example of design dimensions for the distances L1 - L9 are shown in Fig. 5 and Fig. 6, Fig. 7 and Fig. 8 or Fig. 9 and Fig. 10. The unit of dimensions is millimeters (mm). Specifically, in the first example, the distance L1 is 323.5 mm, the distance L2 is 192.7 mm, the distance L3 is 51.3 mm, the distance L4 is 184.0 mm, the distance L5 is 49.0 mm, the distance L6 is 148.6 mm, the distance L7 is 87.0 mm, the distance L8 is 48.1 mm, and the distance L9 is 117.9 mm. In the second example, the distance L1 is 323.5 mm, the distance L2 is 199.9 mm, the distance L3 is 51.3 mm, the distance L4 is 185.8 mm, the distance L5 is 59.0 mm, the distance L6 is 151.4 mm, the distance L7 is 87.0 mm, the distance L8 is 45.1 mm and the distance L9 is 117.9 mm. In the third example, the distance L1 is 323.5 mm, the distance L2 is 204.2 mm, the distance L3 is 51.3 mm, the distance L4 is 187.3 mm, the distance L5 is 67.5 mm, the distance L6 is 160.1 mm, the distance L7 is 87.0 mm, the distance L8 is 43.2 mm and the distance L9 is 117.9 mm.In the first example, the capacity of battery 14 is 8 Ah; in the second example, the capacity of battery 14 is 5 Ah; and in the third example, the capacity of battery 14 is 4 Ah.

[0064] In all of the first to third examples, the distances L1 - L9 satisfy the following equations (1)-(4). 0.5≤L2 / L1≤0.7 3.4≤L4 / L3≤3.8 0.1≤L5 / L1≤0.3 2.8≤L6 / L3≤3.2 0.4≤L8 / L7≤0.7 1.3≤L9 / L7≤1.5

[0065] In embodiments in which such conditions are met, the weight balance of the circular saw for the user is improved when the user grips the first handle portion 51 and the second handle portion 61 and holds the circular saw 10. It is noted that the design of the circular saw 10 can be determined to satisfy at least one of the above-described equations (1)-(6).

[0066] A second embodiment is described with reference to Fig. 11 to 17, in which only points different from those in the first embodiment are described. As clearly shown in Fig. 12 and Fig. 13, in a circular saw 110 according to the second embodiment, the circular saw blade 35 is located on the left side relative to the electric motor 41 (motor housing 11), in contrast to the circular saw 10 (see Fig. 3), in which the circular saw blade 35 is located on the right side relative to the electric motor 41. According to this construction (design), when a user stands on the left side of the circular saw 110 and uses the circular saw 110, the motor housing 11 is not positioned on the user's line of sight toward the circular saw blade 35. Furthermore, the circular saw blade 35 is located closer to the user in the left-right direction. Accordingly, when the user performs cutting using the circular saw 110, the visibility of the circular saw blade 35 visible between a front portion of the fixed cover 33 and a front portion of the base 20 can be improved, especially on the side where the circular saw blade 35 crosses (cuts) the marking line on the workpiece.

[0067] As in Fig. As shown in Figures 11 to 16, the circular saw 110 includes a third handle 170 in addition to the first handle 50 and the second handle 60. The shape of the first handle 50 and the location of the first handle 50 relative to the base 20 are the same as in the first embodiment described above. That is, the first handle 50 is located on the rear side and at an end portion on the upper side of the fixed cover 33, and the first grip portion 51 of the first handle 50 is located at least partially further rearward than the circular saw blade 35.

[0068] The second handle 60 has a second grip portion 61, which is the same as in the first embodiment. The second handle 60 extends in a tubular shape so as to span (extend) between a portion of a right surface of the fixed cover 33, which is further forward than the electric motor 41, and the upper end portion of the front side of the motor housing 11. That is, unlike the circular saw 10 according to the first embodiment, the second handle 60 is located on the right side relative to the circular saw blade 35. Furthermore, the second grip portion 61 of the second handle 60 is located in front of the electric motor 41 (the motor housing 11). This point is the same as in the first embodiment.

[0069] In the present embodiment, the third handle 170 is designed as a rod-shaped handle. The third handle 170 is located to the left of the circular saw blade 35. In other words, the third handle 170 is located on the opposite side of the second handle 60 relative to the circular saw blade 35. As shown in Fig. 11, Fig. 13 and Fig. As shown in Figure 15, the third handle 170 extends linearly (straight) to the left from a left side surface located at the upper end portion of the fixed cover 33. In the present embodiment, the third handle 170 is located at substantially the same position as that of the electric motor 41 in the front-to-back direction. The third handle 170 has a third grip portion 171 that can be gripped by the user. In the present second embodiment, a base end (the right end) of the third handle 170 is screwed into a screw hole formed in the fixed cover 33. That is, the third handle 170 is removable. However, the third handle 170 may be coupled to the fixed cover 33 in a non-removable manner. Furthermore, the third handle 170 may have any shape, for example,Instead of the shape of the rod-shaped handle, the third handle 170 may have the shape of a loop handle, like the first handle 50 or the second handle 60.

[0070] According to the circular saw 110 thus configured, the user can select different handles to use according to the user's working posture. For example, the user can stand to the right of the circular saw 110 and grasp the first handle portion 51 with one hand and the second handle portion 61 with the other hand to use the circular saw 110. Alternatively, the user can stand to the left of the circular saw 110 and grasp the first handle portion 51 with one hand and the third handle portion 171 with the other hand to use the circular saw 110. Furthermore, according to the circular saw 110, the distance between the first handle portion 51 and the second handle portion 61 in the front-to-back direction can be made larger by locating the second handle portion 61 in front of the electric motor 41.Accordingly, the circular saw 110 can be held stably when the user grips the first handle part 51 and the second handle part 61 and uses the circular saw 110.

[0071] Furthermore, in the circular saw 110, the circular saw blade 35 is perpendicular to the base 20, and in the state in which a protruding distance with which the circular saw blade 35 protrudes from the base 20 becomes maximum, the protruding distance L10 (see Fig. 11), with which the circular saw blade 35 protrudes downward beyond the base (below the base) 20, 100 mm or more. According to this configuration, a workpiece having a large thickness can be cut, compared with known circular saws. The protrusion distance L10 can be 150 mm or more. When configured in this manner, a workpiece having a large thickness can be cut. A protrusion distance of 158 mm is disclosed as a specific example in the present embodiment.

[0072] Furthermore, in the circular saw 110, when the torque of the spindle 46 is 5 N / m, the peripheral speed of the blade edge of the circular saw blade 35 is 32.4 m / s. In this case, a value resulting from multiplying the peripheral speed of the blade edge of the circular saw blade 35 by the diameter of the circular saw blade 35 (hereinafter referred to as a "multiplication product") is 0.415 m (= 415 mm) × 32.4 m / s = 13.4 m. 2 / s. The larger the diameter of the circular saw blade 35, the lower the transmission losses of the driving force required to approximate the linear movement, and the higher the cutting efficiency; so if this multiplication product is 6.0 m 2 / s, the workpiece can be cut more efficiently compared to conventional circular saws. This multiplication product can be 10.0 m 2 / s or greater. When configured in this way, cutting efficiency can be further improved.

[0073] Fig. 17 shows the difference in multiplication products between the circular saw 110 and conventional circular saws. The straight line shown by a solid line corresponds to the circular saw 110 according to the present embodiment (the rated voltage of the battery 14 is 36 V, and the diameter of the circular saw blade 35 is 415 mm). The multiplication products are shown for examples where the torques of the spindle 46 are 2, 7, and 10 N / m, and the calculation result of a straight-line approximation thereof is shown. The straight line shown by a dash-dot line corresponds to a conventional circular saw (the rated voltage of the battery is 36 V, and the diameter of the circular saw blade is 165 mm). The multiplication products are shown for examples where the torques of the spindle 46 are 2 and 4 N / m, and the calculation result of a straight-line approximation thereof is shown.The straight line represented by a dashed double-dotted line corresponds to a conventional circular saw incorporating the techniques disclosed in JP 2020-116834 B2 (the rated battery voltage is 18 V, and the diameter of the circular saw blade is 125 mm). The multiplication products are shown for examples where the spindle torques are 1 and 2 N / m, and the calculation result of a straight-line approximation thereof is shown. Since circular saws are normally used in a state where the spindle torque is approximately 4 to 7 N / m, if the multiplication product is used as an index value at a spindle torque of 5 N / m, the cutting efficiency can be satisfactorily evaluated.

[0074] A third embodiment will be described below with reference to Fig.18, in which only points different from those of the second embodiment will be described. A circular saw 210 according to the third embodiment differs from the second embodiment only in the location of the third handle 170. Specifically, the third handle 170 is mounted on the fixed cover 33 at a location in front of the electric motor 41 (the motor housing 11). The fixed cover 33 has a protruding portion 33a protruding upward at the mounting position of the third handle 170. By mounting the third handle 170 to the protruding portion 33a, the third handle 170 can be provided outside the blade edge of the circular saw blade 35, and interference between the circular saw blade 35 and the third handle 170 is avoided.According to the third embodiment, the distance between the first handle part 51 and the third handle part 171 in the front-to-back direction becomes even larger than in the second embodiment. Accordingly, the circular saw 210 can be held even more stably when the user grips the first handle part 51 and the third handle part 171 and uses the circular saw 210.

[0075] Although several embodiments of the present teachings have been explained above, the embodiments described above are merely intended to facilitate understanding of the present invention and do not limit the scope of the present invention. Changes and improvements may be made to the present teachings without departing from the gist of the teachings, and the present teachings include such equivalents. Furthermore, the structural elements described in the claims and the specification may be arbitrarily combined or omitted within a scope that can solve at least one technical problem and / or within a scope that has at least one of the advantages and / or effects described above.

[0076] For example, respective features of the above-described specifications (diameter of the circular saw blade, peripheral speed of the circular saw blade, force of the blade edge of the circular saw blade, rated voltage of the battery 14, speed reduction ratio of the speed reduction mechanism 43, etc.) of the circular saw 10 and the respective features of the various configurations of the circular saw 10 are separable from other features, and each can be applied individually.

[0077] In addition, the specifications of the circular saw 10 described above are not limited to a portable circular saw and are applicable to table saws or sliding circular saws (compound and miter saws) that use a battery as an electric power supply (power source).

[0078] The correspondence relationship between the component elements in the above-described embodiments and the component elements of the present teachings is as follows. However, the component elements in the embodiments are merely examples and do not limit the component elements of the present teachings or the present invention. The circular saw 10 is an example of a "circular saw." The circular saw blade 35 is an example of a "circular saw blade." The electric motor 41 is an example of an "electric motor." The battery mounting part 13 is an example of a "battery mounting part." The battery 14 is an example of a "battery." The speed reduction mechanism 43 is an example of a "speed reduction mechanism." The first handle 50 is an example of a "first handle." The first handle part 51 is an example of a "first handle part." The second handle 60 is an example of a "second handle."The second handle portion 61 is an example of a "second handle portion." The front end portion 52 is an example of an "end portion at the front of a first handle portion." The front end portion 62 is an example of an "end portion at the front of a second handle portion." The first center point 53 is an example of a "first center point." The second center point 63 is an example of a "second center point." The center of gravity 15 is an example of a "first center of gravity." The spindle 46 is an example of a "final output shaft." LIST OF REFERENCE SYMBOLS 10 portable circular saw 11 Engine housing 12 Gearbox housing 13 Battery mounting part 14 Battery 15 Focus on circular saw 16 Focus on battery 20 Base 21 through hole 22 Angle plate 23 Fixing lever 24 bracket 25 swivel shaft 26 Depth control 27 Fixing lever 30 Main body area 33 fixed cover 33a protruding area 34 movable cover 35 circular saw blade 36 Fixation device 41 electric motor 42 Motor shaft 43 Speed ​​reduction mechanism 44 Drive gear 45 Output gear 46 spindle 50 first step 51 first handle part 52 front end area 53 first center point 54 first half area 55 gear levers 60 second handle 61 second handle part 62 front end area 63 second center point 64 second half area AX rotation axis circular saw blade QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2020 - 116 834 B2 [0002, 0003, 0073]

Claims

[1] Circular saw, with a rotating circular saw blade, an electric motor configured to generate rotational power for rotating the circular saw blade, and a battery mounting part configured to removably mount a battery that supplies electric power to the electric motor, where the circular saw blade has a diameter of 300 mm or larger and 460 mm or smaller. [2] A circular saw according to claim 1, wherein the circular saw is configured so that the circular saw blade rotates at a peripheral speed of 70.0 m / s or less under no load. [3] The circular saw according to claim 1, wherein the circular saw is configured so that the circular saw blade rotates at a peripheral speed of 50.0 m / s or less under no load. [4] A circular saw according to any one of claims 1 to 3, wherein the circular saw is configured such that the circular saw blade rotates at a peripheral speed of 25.0 m / s or greater under load. [5] A circular saw according to claim 1, wherein the circular saw is configured such that the circular saw blade rotates at a peripheral speed of 28.0 m / s or greater under load. [6] A circular saw according to any one of claims 1 to 5, wherein the circular saw is configured to rotate such that a force at a blade edge of the circular saw blade under load is 20.0 N or greater. [7] A circular saw according to claim 6, wherein the circular saw is configured to rotate such that a force at a blade edge of the circular saw blade under load is 30.0 N or greater. [8] Circular saw according to one of claims 1 to 7, with the battery, where the nominal voltage of the battery is 18 V or greater and 80 V or less. [9] A circular saw according to claim 8, wherein the nominal voltage of the battery is 36 V. [10] Circular saw according to one of claims 1 to 9, with a speed reduction mechanism configured to transmit the rotational power generated by the electric motor to the circular saw blade at a reduced speed, in which the speed reduction mechanism has a speed reduction ratio of 7 or greater. [11] Circular saw according to one of claims 1 to 10, in which the circular saw is a portable circular saw, the portable circular saw a first handle having a first grip portion, and a second handle having a second grip portion and disposed in front of the first handle when the direction in which cutting advances by the portable circular saw is defined as a front side and the opposite side to the front side is defined as a rear side, and the battery mounting part is configured such that when the battery is mounted on the battery mounting part, the entire battery is arranged between an end portion at the front of the first handle part and an end portion at the front of the second handle part in a front-to-back direction. [12] Circular saw according to one of claims 1 to 10, in which the circular saw is a portable circular saw, the portable circular saw a first handle having a first grip portion, and a second handle having a second grip portion and disposed in front of the first handle when the direction in which cutting advances by the portable circular saw is defined as a front side and the opposite side to the front side is defined as a rear side, and the center of gravity of the circular saw in the state in which the battery is mounted on the battery mounting part is located downward from an end portion on the lower side of the first handle part and at an end portion on the lower side of the second handle part in an up-down direction in the posture of the portable circular saw during normal use thereof. [13] Circular saw according to one of claims 1 to 10, in which the circular saw is a portable circular saw, the portable circular saw a first handle having a first grip part, a second handle having a second grip portion and disposed further forward than the first handle when a direction in which cutting advances by the portable circular saw is defined as a front side and the opposite side to the front side is defined as a rear side, and the battery has, and the center of gravity of the battery, in the state in which the battery is mounted on the battery mounting part, is located downward from an end portion on the lower side of the first handle part and an end portion on the lower side of the second handle part in an up-down direction in the posture of the portable circular saw during normal use thereof. [14] Circular saw according to one of claims 1 to 10, in which the circular saw is a portable circular saw, the portable circular saw a first handle having a first grip portion, and a second handle having a second grip portion and disposed in front of the first handle when the direction in which cutting advances by the portable circular saw is defined as a front side and the opposite side to the front side is defined as the back side, L1 is defined as the distance in the front-back direction between a first center point of the first grip part, which is the center point of an area where the user actually grips the first grip part, and a second center point, which is the center point of the second grip part, L2 is defined as the distance in the front-back direction between the first center point and a first center of gravity, which is the center of gravity of the circular saw in the state in which the battery is mounted on the battery mounting part, and the value of L2 / L1 is 0.5 or greater and 0.7 or less. [15] Circular saw according to one of claims 1 to 14, in which the circular saw is a portable circular saw, a base of the circular saw has a through hole through which the circular saw blade passes during a cutting operation, the side on which the electric motor is located relative to the base is defined as an upper side in an up-down direction, the opposite side thereof in the top-bottom direction is defined as a bottom side, and in a maximum depth state in which the circular saw blade is perpendicular to the base and the circular saw blade protrudes through the through hole to a maximum extent in the up-down direction, a maximum distance from the base to the lowermost peripheral edge of the circular saw blade in the up-down direction is 100 mm or greater. [16] A circular saw according to claim 15, wherein the maximum distance in the maximum depth state is 150 mm or greater. [17] Circular saw, with a rotating circular saw blade, an electric motor configured to generate rotational power for rotating the circular saw blade, a rotatable final output shaft on which the circular saw blade is mounted and to which the rotary power of the electric motor is transmitted, and a battery mounting part configured to removably mount a battery that supplies electric power to the electric motor, in which, in a state in which the torque of the final output shaft is 5 N / m, a multiplication product of the peripheral speed of a blade edge of the circular saw blade and the diameter of the circular saw blade is 6.0 m 2 / s or greater. [18] Circular saw according to claim 17, wherein the multiplication product is 10.0 m 2 / s or greater. [19] Circular saw according to claim 17 or 18, in which the circular saw is a portable circular saw, a base of the circular saw has a through hole through which the circular saw blade passes during a cutting operation, the side in which the circular saw is advanced when the circular saw cuts a workpiece is defined as a front side in a front-back direction, the opposite side thereof in the front-back direction is defined as a back side, the side on which the electric motor is located relative to the base is defined as an upper side in an up-down direction, the opposite side thereof in the top-bottom direction is defined as a bottom side, a direction perpendicular to the front-back direction and the top-bottom direction is defined as a left-right direction, the side, when viewed from the back towards the front, is defined as a right side in the left-right direction, the opposite side thereof in the left-right direction is defined as a left side, and the circular saw blade is on the left side relative to the electric motor. [20] Circular saw according to claim 19, further comprising a first handle having a first grip portion located at least partially rearward of the circular saw blade in the front-to-back direction, a second handle having a second grip portion located in front of the electric motor in the front-to-back direction and to the right of the circular saw blade in the left-to-right direction, and a third handle, which has a third handle part located to the left of the circular saw blade in the left-right direction. [21] A circular saw according to claim 20, wherein the third handle part is located in front of the electric motor in the front-to-back direction.

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