Work machine

Abstract

To provide a technique capable of increasing the maximum cut-in depth of a rotary blade.SOLUTION: A work machine includes: a rotary blade; an output shaft to which the rotary blade is attached; a prime mover that rotates and drives the output shaft; a work machine body; a blade cover that covers a part of the rotary blade; and a cover holding mechanism that holds the blade cover rotatably around a cover rotation axis. The cover holding mechanism includes: a first member that includes a first cylindrical part which surrounds the output shaft, a male screw which is defined on an outer peripheral surface of the first cylindrical part, and a first cover support part which supports the blade cover from a first direction along the cover rotation axis; and a second member that includes a second cylindrical part which is arranged on the outside of the first cylindrical part, a female screw which is defined on an inner peripheral surface of the second cylindrical part and in which the male screw is screwed, and a second cover support part which supports the blade cover from a second direction opposite to the first direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a work machine. [Background technology]

[0002] Patent Document 1 discloses a working machine including a rotary blade for cutting an object, an output shaft to which the rotary blade is attached, a prime mover for driving the output shaft to rotate, a working machine body for rotatably holding the output shaft and accommodating the prime mover, a blade cover for covering a part of the rotary blade, and a cover holding mechanism provided on the working machine body for rotatably holding the blade cover around a cover rotation axis. The cover holding mechanism includes a member for clamping the blade cover and a screw member for fastening the member. In this cover holding mechanism, a hole for avoiding interference with the output shaft and a hole for attaching the screw member are provided separately from each other in the member for clamping the blade cover. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-188606 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of the work machine disclosed in Patent Document 1, the cover holding mechanism may become large in the radial direction of the cover rotation shaft. In addition, the cover holding mechanism may become large in the radial direction, which may reduce the maximum cutting depth of the rotary blade. This specification provides a technology that can increase the maximum cutting depth of the rotary blade. [Means for solving the problem]

[0005] The working machine disclosed in this specification includes a rotary blade for cutting an object to be cut, an output shaft to which the rotary blade is attached, a prime mover for rotatably driving the output shaft, a working machine body for rotatably holding the output shaft and housing the prime mover, a blade cover for covering a part of the rotary blade, and a cover holding mechanism provided on the working machine body for rotatably holding the blade cover around a cover rotation axis. The cover holding mechanism includes a first member including a first cylindrical portion surrounding the output shaft, a male screw defined on an outer circumferential surface of the first cylindrical portion, and a first cover support portion supporting the blade cover from a first direction along the cover rotation axis, and a second member including a second cylindrical portion disposed outside the first cylindrical portion, a female screw defined on an inner circumferential surface of the second cylindrical portion and into which the male screw is screwed, and a second cover support portion supporting the blade cover from a second direction opposite to the first direction.

[0006] According to the above configuration, by passing the output shaft inside the first cylindrical part, it is possible to prevent the cover holding mechanism from interfering with the output shaft. Then, by screwing the male thread defined on the outer peripheral surface of the first cylindrical part into the female thread of the second member, it is possible to sandwich the blade cover between the first member and the second member. Therefore, it is not necessary to prepare a screw member as disclosed in Patent Document 1. Accordingly, it is not necessary to provide a hole for attaching the screw member, so that the cover holding mechanism can be made smaller in the radial direction of the cover rotation shaft. Therefore, it is possible to increase the maximum cutting depth of the rotary blade. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an overall perspective view of a power cutter 2 according to an embodiment, as viewed from above on the front right. [Diagram 2] 1 is a left view of the internal structure of a main housing 10 of a power cutter 2 according to an embodiment of the present invention. FIG. [Diagram 3] 2 is a left view of the internal structure of a belt housing 12 of the power cutter 2 according to the embodiment. FIG. [Figure 4]3 is a cross-sectional view showing the structure in the vicinity of a rotary blade holding mechanism 56 and a cover holding mechanism 76 of the power cutter 2 according to the embodiment, taken along the line VV in FIG. 2. FIG. [Diagram 5] 3 is a cross-sectional view showing a structure in the vicinity of a cover holding mechanism 76 of the power cutter 2 according to the embodiment, taken along line VV in FIG. 2. FIG. [Figure 6] 2 is an exploded view of a cover holding mechanism 76 of the power cutter 2 according to the embodiment. FIG. [Figure 7] 1 is a bottom view of the structure of the power cutter 2 according to the embodiment, in the vicinity of the rotary blade holding mechanism 56 and the cover holding mechanism 76. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Representative and non-limiting examples of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed can be used separately or together with other features and inventions to provide further improved working machines.

[0009] In addition, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, but are specifically described only to illustrate representative embodiments of the present invention. Furthermore, the various features of the following representative embodiments and the various features described in the claims do not have to be combined in the exact manner of the embodiments described herein or in the order listed in order to provide additional and useful embodiments of the present invention.

[0010] All features described in the specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0011] In one or more embodiments, each of the first cover support portion and the second cover support portion may support the blade cover over substantially the entire circumference of the cover rotation shaft.

[0012] If the first cover support portion and the second cover support portion do not support the blade cover over substantially the entire circumference of the cover rotation shaft, the blade cover may rattle relative to the work machine body. According to the above configuration, the first cover support portion and the second cover support portion each support the blade cover over substantially the entire circumference of the cover rotation shaft. This makes it possible to prevent the blade cover from rattling relative to the work machine body.

[0013] In one or more embodiments, the work machine may further include a bearing that rotatably supports the output shaft. The first member may further include a first bearing abutment portion that abuts against the bearing from the first direction. The second member may further include a second bearing abutment portion that abuts against the bearing from the second direction.

[0014] According to the above-mentioned configuration, the cover holding mechanism also functions as a bearing retainer by clamping the bearing, which eliminates the need for a separate bearing retainer, thereby reducing the number of parts of the work machine.

[0015] In one or more embodiments, the male thread, the female thread, and the bearing may overlap each other when viewed in a direction perpendicular to the cover rotation axis.

[0016] According to the above configuration, the cover holding mechanism can be made smaller in size in the axial direction of the cover rotation shaft.

[0017] In one or more embodiments, an elastic member may be provided at least one between the first cover support portion and the blade cover and between the second cover support portion and the blade cover.

[0018] It is expected that a material with high hardness (e.g., metal) will be used for each of the first member, the second member, and the blade cover. Therefore, if the first cover support part (or the second cover support part) and the blade cover are in contact with each other, the first cover support part (or the second cover support part) and the blade cover will be significantly worn as the blade cover rotates. According to the above configuration, an elastic member with a relatively low hardness is provided between the first cover support part (or the second cover support part) and the blade cover. Therefore, it is possible to suppress wear of the first cover support part (or the second cover support part) and the blade cover. Furthermore, according to the above configuration, it is possible to suppress rattling of the blade cover relative to the work machine body.

[0019] In one or more embodiments, the work machine may further include a rotary blade holding mechanism provided on the output shaft and holding the rotary blade so that the rotary blade is fixed to the output shaft. When viewed from a direction perpendicular to the rotation axis of the output shaft, an outer peripheral surface of a portion of the cover holding mechanism that is between the rotary blade and the blade cover may be retracted radially inward of the rotation axis of the output shaft with respect to an outer peripheral surface of the rotary blade holding mechanism.

[0020] According to the above-mentioned configuration, the cover holding mechanism can be made small in size to a degree that does not affect the maximum cutting depth of the rotary blade, thereby making it possible to maximize the maximum cutting depth of the rotary blade.

[0021] In one or more embodiments, at least one of the first member and the second member may include a polygonal prism shape with a central axis aligned along the cover rotation axis.

[0022] If the first member and the second member do not have a polygonal prism shape, the first member and the second member cannot be gripped with a tool such as a wrench. In this case, it may be difficult for the manufacturer of the work machine (specifically, the person who assembles the work machine) to fasten the male screw and the female screw with sufficient fastening torque. According to the above configuration, since at least one of the first member and the second member has a polygonal prism shape, at least one of the first member and the second member can be gripped with a tool such as a wrench. Therefore, it becomes easy for the manufacturer of the work machine to fasten the male screw and the female screw with sufficient fastening torque.

[0023] In one or more embodiments, at least one of the first member and the second member may be made of an aluminum alloy.

[0024] Among metals, aluminum alloys are relatively light. In addition, aluminum alloys can be easily processed into various shapes, including screws. According to the above configuration, an aluminum alloy is used for at least one of the first member and the second member. Therefore, at least one of the first member and the second member can be made lighter. Furthermore, at least one of the first member and the second member can be easily processed.

[0025] (Example) As shown in FIG. 1, the working machine of this embodiment is a power cutter 2. The power cutter 2 is a handheld working machine that can be carried by a user. The power cutter 2 cuts an object to be cut, such as stone or iron, using a rotary blade 4 having a plurality of cutting edges or grinding wheels on its outer periphery. A rechargeable battery pack B is detachably attached to the power cutter 2. The power cutter 2 operates by power supplied from the battery pack B. As shown in FIG. 2, the power cutter 2 can be placed on a flat surface P (for example, the ground).

[0026] In this specification, the front-rear, up-down, left-right directions are defined based on the state in which the power cutter 2 is placed on the plane P. Specifically, the direction perpendicular to the plane P and from the plane P toward the power cutter 2 is defined as the upward direction, and the direction from the power cutter 2 toward the plane P is defined as the downward direction. In addition, the direction perpendicular to the upward-downward direction and in which the rotation axis A (also simply referred to as axis A) of the rotary blade 4 extends is defined as the left-right direction. The direction perpendicular to the upward-downward and left-right directions and in which the rotary blade 4 is facing is defined as the forward direction, and the opposite direction is defined as the rearward direction.

[0027] As shown in Fig. 1, the power cutter 2 includes a blade cover 6 that covers a portion of the rotary blade 4, and a power cutter body 8 that holds the rotary blade 4 and the blade cover 6. Although details will be described later, the blade cover 6 is rotatably attached to the power cutter body 8. The blade cover 6 is provided with a handle 6a for a user to hold. By holding the handle 6a provided on the blade cover 6, the user can rotate the blade cover 6 relatively easily.

[0028] The power cutter body 8 includes a main housing 10 and a belt housing 12. An opening 14 is defined in the top surface of the main housing 10, into which the battery pack B can be inserted from above. The belt housing 12 extends forward and upward as viewed from the main housing 10.

[0029] The main housing 10 is provided with a front handle 16 that the user can hold with one hand (e.g., the left hand) and a rear handle 18 that the user can hold with the other hand (e.g., the right hand). The front handle 16 is a pipe-shaped member attached to the main housing 10. The front handle 16 extends mainly above and to the left of the main housing 10. The rear handle 18 is defined by a part of the main housing 10. The rear handle 18 is disposed rearward of the front handle 16. The user can carry the power cutter 2 by holding the front handle 16 with one hand and the rear handle 18 with the other hand.

[0030] A water supply hose 20 is attached to the blade cover 6. One end of the water supply hose 20 is connected to a side wall of the blade cover 6 via a plug 22. The other end of the water supply hose 20 is provided with a water supply connector 24. The water supply connector 24 is fixed to the main housing 10 and is connected to an external water source, such as a water faucet. A user can perform cutting work with the power cutter 2 while supplying water to the inside of the blade cover 6 via the water supply hose 20.

[0031] 2 and 3, the power cutter 2 includes a power interface 26, a control unit 28, an electric motor 30, and a power transmission mechanism 32. As shown in Fig. 2, the power interface 26, the control unit 28, and the electric motor 30 are provided in the main housing 10. As shown in Fig. 3, the power transmission mechanism 32 is provided in the belt housing 12.

[0032] 2 is an interface for electrically connecting the battery pack B to the power cutter 2. The power interface 26 includes an external terminal 34 electrically connected to the control unit 28. When the battery pack B is attached to the power cutter 2, the external terminal 34 is connected to a connection terminal (not shown) provided on the battery pack B.

[0033] The control unit 28 controls the operation of the electrical components included in the power cutter 2. The control unit 28 includes, for example, an inverter circuit including a switching element, and a control circuit that controls the operation of the switching element. The control unit 28 can control the operation of the electric motor 30 by adjusting the power supplied from the battery pack B and supplying the power to the electric motor 30.

[0034] The electric motor 30 is, for example, an inner rotor type DC brushless motor. When power is supplied to the electric motor 30, the electric motor 30 rotates a motor shaft (not shown).

[0035] The power transmission mechanism 32 shown in FIG. 3 includes a planetary gear mechanism (not shown) connected to the motor shaft (not shown), an input shaft 36 connected to the planetary gear mechanism, an input pulley 38 fixed to the input shaft 36, an output shaft 40 to which the rotary blade 4 is attached, an output pulley 42 fixed to the output shaft 40, and a transmission belt 44 stretched between the input pulley 38 and the output pulley 42. The planetary gear mechanism reduces the speed of the rotation of the motor shaft and transmits it to the input shaft 36. The input shaft 36 is supported by a bearing (not shown) provided in the belt housing 12 so as to be rotatable around an axis along the left-right direction. The input pulley 38 and the output pulley 42 are toothed pulleys, and the transmission belt 44 is a toothed belt. The teeth provided on the input pulley 38 mesh with the teeth provided on the transmission belt 44. The teeth provided on the output pulley 42 mesh with the teeth provided on the transmission belt 44. Therefore, the input pulley 38, the transmission belt 44, and the output pulley 42 rotate in conjunction with one another. The output shaft 40 is supported rotatably about an axis A by bearings 78, 80 (see FIG. 4).

[0036] The electric motor 30 rotates the rotary blade 4 via a power transmission mechanism 32. In this case, the power generated by the electric motor 30 is transmitted to the rotary blade 4 via a motor shaft (not shown), a planetary gear mechanism (not shown), an input shaft 36, an input pulley 38, a transmission belt 44, an output pulley 42, and an output shaft 40 in this order.

[0037] The belt housing 12 is provided with a shaft lock 46. The shaft lock 46 is biased upward against the belt housing 12 by a spring. When the user presses the shaft lock 46 downward against the biasing force of the spring, the output pulley 42 is locked and the rotation of the output shaft 40 is prohibited. When the user stops pressing the shaft lock 46, the biasing force of the spring pushes the shaft lock 46 back upward. Then, the output pulley 42 is unlocked and the rotation of the output shaft 40 is permitted.

[0038] As shown in FIG. 2, the power cutter 2 further includes a trigger switch 48, a trigger lever 50, a trigger lock 52, and an operation button 54. The trigger switch 48, the trigger lever 50, the trigger lock 52, and the operation button 54 are provided on the rear handle 18. The trigger lever 50 is disposed at a position where it can be operated by the index finger of the hand gripping the rear handle 18. When the trigger lever 50 is pulled up, the trigger switch 48 is pressed down. When the trigger switch 48 is pressed down, the trigger switch 48 outputs a trigger-on signal to the control unit 28. The control unit 28 operates the electric motor 30 while the trigger-on signal is being output from the trigger switch 48. On the other hand, when the trigger lever 50 is not pulled up, the trigger switch 48 is not pressed down. When the trigger switch 48 is not pressed down, the trigger switch 48 outputs a trigger-off signal to the control unit 28. The control unit 28 stops the electric motor 30 while the trigger-off signal is being output from the trigger switch 48. The trigger lock 52 is disposed in a position where it can be operated by the thumb of the hand gripping the rear handle 18. The trigger lock 52 is biased leftward with respect to the rear handle 18 by a spring (not shown). Normally, the trigger lock 52 locks the trigger lever 50 so that the trigger lever 50 does not press the trigger switch 48. In this state, the trigger lever 50 is prohibited from being pulled up. When the trigger lock 52 is pushed rightward against the biasing force of the spring, the trigger lever 50 is unlocked and the trigger lever 50 is permitted to be pulled up. Therefore, the user can operate the electric motor 30 and rotate the rotary blade 4 by pulling up the trigger lever 50 with the trigger lock 52 pressed in.

[0039] The operation button 54 is disposed on the upper surface of the rear handle 18. In this embodiment, the control unit 28 starts or stops the power supply to a lighting device (not shown) provided on the front surface of the main housing 10 in response to the operation of the operation button 54. In other words, the operation button 54 is a button for switching the lighting device ON and OFF.

[0040] (Rotary blade holding mechanism 56) As shown in FIG. 4, the power cutter 2 further includes a rotary blade holding mechanism 56. The rotary blade holding mechanism 56 is provided on the output shaft 40. The rotary blade holding mechanism 56 holds the rotary blade 4 so that the rotary blade 4 is fixed to the output shaft 40. The rotary blade holding mechanism 56 includes a ring bush 58, a left flange 60, a right flange 62, a bolt 64, and a washer 66. The ring bush 58 is slidably and rotatably attached to the output shaft 40. The ring bush 58, together with the output shaft 40, is inserted into a through hole 68 provided in the rotary blade 4. The ring bush 58 is disposed so as to close the gap between the output shaft 40 and the periphery of the through hole 68. The left flange 60 and the right flange 62 have a substantially disk shape expanding around the axis A. The left flange 60 and the right flange 62 are slidably and non-rotatably attached to the output shaft 40. The left flange 60 has a central portion offset leftward from the left face of the rotary blade 4, and a portion radially outer than the central portion abuts against the left face of the rotary blade 4. The right flange 62 has a central portion offset rightward from the right face of the rotary blade 4, and a portion radially outer than the central portion abuts against the right face of the rotary blade 4. The bolt 64 is, for example, a hexagonal bolt, and has a male thread 70. The male thread 70 is screwed into a female thread 72 defined in the output shaft 40. A washer 66 is disposed between the head of the bolt 64 and the left flange 60.

[0041] The bolt 64 fastens the right flange 62, the rotary blade 4, the left flange 60, and the washer 66 to the output shaft 40. In this state, the right flange 62, the rotary blade 4, the left flange 60, and the washer 66 are sandwiched between a flange portion 74 provided on the output shaft 40 and the head of the bolt 64. As a result, the rotary blade 4 is fixed to the output shaft 40.

[0042] By loosening the bolt 64, the user can remove the bolt 64 (and the washer 66) from the output shaft 40. In a state in which the bolt 64 (and the washer 66) has been removed from the output shaft 40, the user can slide each of the left flange 60, the rotary blade 4, the ring bush 58, and the right flange 62 leftward relative to the output shaft 40 to remove them. This allows the user to remove the rotary blade 4 and the rotary blade holding mechanism 56 from the output shaft 40. The state of the rotary blade 4 and the rotary blade holding mechanism 56 after being removed from the output shaft 40 is shown in FIG. 5.

[0043] (Cover retention mechanism 76) The power cutter 2 further includes a cover holding mechanism 76. The cover holding mechanism 76 is provided on the belt housing 12. The cover holding mechanism 76 holds the blade cover 6 rotatably around the axis A. The cover holding mechanism 76 also rotatably holds the output shaft 40 via two bearings 78, 80. In this embodiment, for convenience, the one of the two bearings 78, 80 having a smaller diameter is referred to as the "small diameter bearing 78," and the one of the two bearings 78, 80 having a larger diameter is referred to as the "large diameter bearing 80."

[0044] As shown in FIG. 6, the cover retention mechanism 76 includes a base member 82, a cap member 84, a rubber ring 86, a ring bushing 88, a left washer 90, and a right washer 92.

[0045] As shown in FIG. 5, the base member 82 is a member that defines the left side portion of the belt housing 12. The base member 82 is made of a metal (for example, a magnesium alloy). The base member 82 includes a first cylindrical portion 94, a male screw 96, a first cover support surface 98, a small diameter bearing support portion 100, and a large diameter bearing support portion 102. One end of the first cylindrical portion 94 opens into the inside of the belt housing 12. The other end of the first cylindrical portion 94 opens into the outside of the belt housing 12. The output shaft 40 straddles the inside and outside of the belt housing 12 via the first cylindrical portion 94. The first cylindrical portion 94 extends so as to surround the output shaft 40. The male screw 96 is defined on the outer circumferential surface of the first cylindrical portion 94. The first cover support surface 98 is a flat surface that is defined in an annular shape around the first cylindrical portion 94. The first cover support surface 98 expands in the radial and circumferential directions of the axis A. The first cover support surface 98 supports the blade cover 6 from the right side via the rubber ring 86 and the right side washer 92. The small diameter bearing support portion 100 and the large diameter bearing support portion 102 are formed by providing a step on the inner circumferential surface of the first cylindrical portion 94. The small diameter bearing support portion 100 abuts against the small diameter bearing 78 from the right side. The large diameter bearing support portion 102 abuts against the large diameter bearing 80 from the right side.

[0046] The ring bush 88 is slidably and rotatably attached to the outer circumferential surface of the first cylindrical portion 94 of the base member 82. The ring bush 88, together with the first cylindrical portion 94, fits into a through hole 104 provided in the blade cover 6. The ring bush 88 is disposed so as to close the gap between the first cylindrical portion 94 and the periphery of the through hole 104.

[0047] The cap member 84 is made of a metal (for example, an aluminum alloy). The cap member 84 includes a second cylindrical portion 106, a female screw 108, a second cover support surface 110, and a large diameter bearing pressing portion 112. The second cylindrical portion 106 is disposed on the outside of the first cylindrical portion 94. The female screw 108 is defined on the inner peripheral surface of the second cylindrical portion 106. The male screw 96 of the base member 82 is screwed into the female screw 108. The second cover support surface 110 is a flat surface defined in an annular shape at the right end of the second cylindrical portion 106. The second cover support surface 110 spreads in the radial direction and the circumferential direction of the axis A. The second cover support surface 110 supports the blade cover 6 from the left side via the left washer 90. The large diameter bearing pressing portion 112 protrudes from the left end of the second cylindrical portion 106 toward the inside in the radial direction of the axis A. The large diameter bearing pressing portion 112 abuts against the large diameter bearing 80 from the left.

[0048] The rubber ring 86, the right washer 92, the blade cover 6, and the left washer 90 are sandwiched between the first cover support surface 98 of the base member 82 and the second cover support surface 110 of the cap member 84. This allows the blade cover 6 to be held around the axis A. The force that sandwiches the blade cover 6 (also called the axial force) depends on the tightening torque of the cap member 84 (i.e., the tightening torque of the female screw 108 relative to the male screw 96). Specifically, the greater the tightening torque of the cap member 84, the greater the force that sandwiches the blade cover 6. The tightening torque of the cap member 84 is adjusted so that the cap member 84 does not easily loosen during use by the user. For example, the tightening torque of the cap member 84 is within a range of 20 N·m to 35 N·m.

[0049] As shown in FIG. 6, the cap member 84 includes a flange portion 114 and a hexagonal portion 116. The flange portion 114 protrudes from the right end of the second cylindrical portion 106 toward the outside in the radial direction of the axis A. The outer peripheral surface of the flange portion 114 has a cylindrical shape. The first cover support surface 98 corresponds to the lower surface of the flange portion 114. The hexagonal portion 116 is provided to the left of the flange portion 114. The hexagonal portion 116 has a hexagonal column shape with a central axis extending along the axis A. A person who assembles the power cutter 2 can tighten the cap member 84 by holding the hexagonal portion 116 with a tool such as a wrench and rotating the tool around the axis A. In addition, the outer peripheral surface of the hexagonal portion 116 is retreated to the inside in the radial direction of the axis A from the outer peripheral surface of the flange portion 114.

[0050] As shown in FIG. 5, the small diameter bearing 78 is sandwiched between the small diameter bearing receiving portion 100 and a step portion 118 provided on the output shaft 40. This holds the small diameter bearing 78 in a predetermined position. The large diameter bearing 80 is sandwiched between the large diameter bearing receiving portion 102 and the large diameter bearing pressing portion 112. This holds the large diameter bearing 80 in a predetermined position. The large diameter bearing 80 is held in a position overlapping the male thread 96 and the female thread 108 when viewed from a direction perpendicular to the axis A. The expression "overlap" here means that a portion of the large diameter bearing 80 projected along the radial direction of the axis A overlaps with the male thread 96 and the female thread 108. The right end of the large diameter bearing 80 is disposed to the left of the right end of the male thread 96 and to the right of the left end of the male thread 96. The right end of the large diameter bearing 80 is disposed to the left of the right end of the female thread 108 and to the right of the left end of the female thread 108 .

[0051] 7, the portion of the cap member 84 with the largest outer diameter (the flange 114) is retracted radially inward of the axis A from the portion of the rotary blade holding mechanism 56 with the largest outer diameter (the left flange 60 or the right flange 62). Therefore, the outer peripheral surface of the cap member 84 is retracted radially inward of the axis A from the outer peripheral surface of the rotary blade holding mechanism 56. In addition, the outer peripheral surface of the cap member 84 is retracted radially inward of the axis A from the outer surface of the base member 82.

[0052] (Modification) The working machine may be a working machine other than the power cutter 2. For example, the working machine may be an electric circular saw or a tipped saw.

[0053] The working machine may be equipped with a prime mover other than the electric motor 30. For example, the working machine may be equipped with an engine.

[0054] The work machine may be provided with a connector for connecting to an external power source (for example, a commercial power source). In this case, the work machine may be operated by power supplied from the external power source instead of by power supplied from the battery pack B.

[0055] The base member 82 may be provided with a female thread instead of the male thread 96. In this case, the cap member 84 may be provided with a male thread instead of the female thread 108. The blade cover 6 may be held around the axis A by fastening the male thread of the cap member 84 to the female thread of the base member 82.

[0056] The rotation axis of the blade cover 6 does not have to coincide with the rotation axis A of the rotary blade 4. For example, the rotation axis of the blade cover 6 may be slightly offset with respect to the rotation axis A of the rotary blade 4. In addition, the rotation axis of the blade cover 6 may be slightly inclined with respect to the rotation axis A of the rotary blade 4.

[0057] The first cover support surface 98 (and / or the second cover support surface 110) may not extend continuously around the entire circumference of the axis A. For example, the first cover support surface 98 (and / or the second cover support surface 110) may extend over a portion of the circumference of the axis A. Alternatively, the first cover support surface 98 (and / or the second cover support surface 110) may be provided discretely along the circumference of the axis A.

[0058] The cap member 84 does not have to include the large diameter bearing retainer 112. Even in this case, the large diameter bearing 80 is sandwiched between the large diameter bearing receiving portion 102 and the flange portion 74 provided on the output shaft 40 and held in a predetermined position.

[0059] The base member 82 may not include the small diameter bearing receiving portion 100 (and / or the large diameter bearing receiving portion 102). In this case, the belt housing 12 may be provided with a member for receiving the small diameter bearing 78 (and / or the large diameter bearing 80).

[0060] The large diameter bearing 80 does not have to be held in a position overlapping with the male thread 96 and the female thread 108 when viewed in a direction perpendicular to the axis A.

[0061] The cover holding mechanism 76 may not include at least one of the rubber ring 86, the left washer 90, and the right washer 92. For example, the first cover support surface 98 may abut against the right surface of the blade cover 6 to support the blade cover 6. Also, the second cover support surface 110 may abut against the left surface of the blade cover 6 to support the blade cover 6.

[0062] An elastic member equivalent to the rubber ring 86 may be provided between the second cover support surface 110 and the blade cover 6. In this case, the rubber ring 86 may or may not be provided between the first cover support surface 98 and the blade cover 6.

[0063] At least a part of the outer circumferential surface of the cap member 84 may be located radially outward of the axis A relative to the outer circumferential surface of the rotary blade holding mechanism 56. At least a part of the outer circumferential surface of the cap member 84 may be located radially outward of the axis A relative to the outer surface of the base member 82.

[0064] The shape of the outer surface of the cap member 84 may be changed as appropriate. For example, the hexagonal portion 116 may be replaced with another polygonal prism shape (for example, a square prism shape or an octagonal prism shape). Alternatively, the hexagonal portion 116 may be replaced with a cylindrical shape. In this case, it may be impossible to grip the cap member 84 with a tool such as a wrench.

[0065] The material used for the cap member 84 is not limited to an aluminum alloy. For example, a metal other than an aluminum alloy (e.g., a magnesium alloy) may be used for the cap member 84. Alternatively, a resin (e.g., nylon) may be used for the cap member 84.

[0066] The material used for the base member 82 is not limited to magnesium alloy. For example, a metal other than an aluminum alloy (e.g., an aluminum alloy) may be used for the base member 82. Alternatively, a resin (e.g., nylon) may be used for the base member 82.

[0067] (Features of the embodiment) As described above, in one or more embodiments, the power cutter 2 (an example of a work machine) comprises a rotary blade 4 for cutting an object to be cut, an output shaft 40 to which the rotary blade 4 is attached, an electric motor 30 (an example of a prime mover) that rotates and drives the output shaft 40, a power cutter body 8 (an example of a work machine body) that rotatably holds the output shaft 40 and houses the electric motor 30, a blade cover 6 that covers part of the rotary blade 4, and a cover holding mechanism 76 provided on the power cutter body 8 and that rotatably holds the blade cover 6 around axis A (an example of a cover rotation axis). The cover retaining mechanism 76 comprises a base member 82 (an example of a first member) including a first cylindrical portion 94 that surrounds the output shaft 40, a male thread 96 defined on the outer peripheral surface of the first cylindrical portion 94, and a first cover support surface 98 (an example of a first cover support portion) that supports the blade cover 6 from the right direction (an example of a first direction), and a cap member 84 (an example of a second member) including a second cylindrical portion 106 that is arranged on the outside of the first cylindrical portion 94, a female thread 108 defined on the inner peripheral surface of the second cylindrical portion 106 and into which the male thread 96 is screwed, and a second cover support surface 110 (an example of a second cover support portion) that supports the blade cover 6 from the left direction (an example of a second direction).

[0068] According to the above configuration, by passing the output shaft 40 inside the first cylindrical portion 94, it is possible to prevent the cover holding mechanism 76 from interfering with the output shaft 40. Then, by screwing the male thread 96 defined on the outer peripheral surface of the first cylindrical portion 94 into the female thread 108 of the cap member 84, it is possible to sandwich the blade cover 6 between the base member 82 and the cap member 84. Therefore, it is not necessary to prepare a screw member as disclosed in Patent Document 1. Accordingly, it is not necessary to provide a hole for attaching the screw member, so that the cover holding mechanism 76 can be made smaller in the radial direction of the axis A. Therefore, the maximum cutting depth of the rotary blade 4 can be increased.

[0069] In one or more embodiments, the first cover bearing surface 98 and the second cover bearing surface 110 each support the blade cover 6 substantially around the entire axis A.

[0070] If the first cover support surface 98 and the second cover support surface 110 did not support the blade cover 6 over approximately the entire circumference of the axis A, the blade cover 6 may rattle relative to the power cutter body 8. According to the above configuration, the first cover support surface 98 and the second cover support surface 110 each support the blade cover 6 over approximately the entire circumference of the axis A. This makes it possible to prevent the blade cover 6 from rattling relative to the power cutter body 8.

[0071] In one or more embodiments, the power cutter 2 further includes a large diameter bearing 80 (an example of a bearing) that rotatably supports the output shaft 40. The base member 82 further includes a large diameter bearing receiving portion 102 (an example of a first bearing abutment portion) that abuts against the large diameter bearing 80 from the right direction. The cap member 84 further includes a large diameter bearing pressing portion 112 (an example of a second bearing abutment portion) that abuts against the large diameter bearing 80 from the left direction.

[0072] According to the above configuration, the cover holding mechanism 76 sandwiches the large diameter bearing 80, and therefore also functions as a retainer for the large diameter bearing 80. Therefore, it is not necessary to separately provide a retainer for the large diameter bearing 80, and the number of parts of the power cutter 2 can be reduced.

[0073] In one or more embodiments, when viewed perpendicular to axis A, male threads 96, female threads 108, and large bearing 80 overlap one another.

[0074] According to the above-described configuration, the cover holding mechanism 76 can be made smaller in size in the axial direction of the axis A.

[0075] In one or more embodiments, a rubber ring 86 (an example of an elastic member) is provided between the first cover support surface 98 and the blade cover 6 (an example of at least one of between the first cover support portion and the blade cover and between the second cover support portion and the blade cover).

[0076] It is expected that the base member 82, the cap member 84, and the blade cover 6 will each be made of a material with high hardness (for example, metal). Therefore, if the first cover support surface 98 and the blade cover 6 are in contact with each other, the first cover support surface 98 and the blade cover 6 will be significantly worn away as the blade cover 6 rotates. With the above configuration, the rubber ring 86 with a relatively low hardness is provided between the first cover support surface 98 and the blade cover 6. Therefore, it is possible to suppress wear of the first cover support surface 98 and the blade cover 6. Furthermore, with the above configuration, it is possible to suppress rattling of the blade cover 6 relative to the power cutter body 8.

[0077] In one or more embodiments, the power cutter 2 further includes a rotary blade holding mechanism 56 that is provided on the output shaft 40 and holds the rotary blade 4 so that the rotary blade 4 is fixed to the output shaft 40. When viewed from a direction perpendicular to the axis A (an example of the rotation axis of the output shaft), the outer circumferential surface of a cap member 84 (an example of a portion of the cover holding mechanism that is present between the rotary blade and the blade cover) is retracted radially inward of the axis A relative to the outer circumferential surface of the rotary blade holding mechanism 56.

[0078] According to the above-described configuration, the cover holding mechanism 76 can be made smaller in size to a degree that does not affect the maximum cutting depth of the rotary blade 4. This allows the maximum cutting depth of the rotary blade 4 to be made as large as possible.

[0079] In one or more embodiments, cap member 84 (an example of at least one of the first member and the second member) includes a hexagonal portion 116 (an example of a polygonal prism shape) with a central axis along axis A.

[0080] If the base member 82 and the cap member 84 did not have the hexagonal portion 116, the base member 82 and the cap member 84 would not be able to be gripped with a tool such as a wrench. In this case, it may be difficult for the manufacturer of the power cutter 2 (specifically, the person who assembles the power cutter 2) to fasten the male screw 96 and the female screw 108 with sufficient fastening torque. According to the above configuration, since the cap member 84 has the hexagonal portion 116, the cap member 84 can be gripped with a tool such as a wrench. This makes it easier for the manufacturer of the power cutter 2 to fasten the male screw 96 and the female screw 108 with sufficient fastening torque.

[0081] In one or more embodiments, the cap member 84 (an example of at least one of the first member and the second member) is made of an aluminum alloy.

[0082] Among metals, aluminum alloys are relatively light. Furthermore, aluminum alloys can be easily processed into various shapes, including screws. According to the above configuration, an aluminum alloy is used for the cap member 84. This allows the cap member 84 to be lightweight. Furthermore, the cap member 84 can be easily processed. [Explanation of symbols]

[0083] 2: Power cutter 4: Rotary blade 6: Blade cover 6a: Toride 8: Power cutter body 10: Main housing 12: Belt housing 14: Opening 16: Front handle 18: Rear handle 20: Water supply hose 22: Plug 24: Water supply connector 26: Power interface 28: Control unit 30: Electric motor 32: Power transmission mechanism 34: External terminal 36: Input shaft 38: Input pulley 40: Output shaft 42: Output pulley 44: Transmission belt 46: Shaft lock 48: Trigger switch 50: Trigger lever 52: Trigger lock 54: Operation button 56: Rotary blade holding mechanism 58: Ring bush 60: Left flange 62: Right flange 64: Bolt 66: Washer 68:Through hole 70: Male thread 72: Female thread 74: Flange part 76: Cover retention mechanism 78: Small diameter bearing 80: Large diameter bearing 82: Base material 84: Cap member 86: Rubber ring 88: Ring bush 90: Left side washer 92: Right side washer 94: First cylindrical part 96: Male thread 98: First cover support surface 100: Small diameter bearing support 102: Large diameter bearing support 104: Through hole 106: Second cylindrical portion 108: Female thread 110: Second cover support surface 112: Large diameter bearing holder 114: Flange 116:Hexagonal part 118: Step B: Battery pack

Claims

1. A rotating blade for cutting the material to be cut, The output shaft to which the aforementioned rotating blade is attached, A prime mover that rotates the output shaft, The work machine body rotatably holds the output shaft and houses the prime mover, A blade cover that covers a portion of the aforementioned rotating blade, The work machine body is provided with a cover holding mechanism that holds the blade cover so that it can rotate around the cover rotation axis, The cover holding mechanism is A first member comprising: a first cylindrical portion surrounding the output shaft; a male screw defined on the outer circumferential surface of the first cylindrical portion; and a first cover support portion supporting the blade cover from a first direction along the cover rotation axis; A work machine comprising a second member including a second cylindrical portion disposed on the outside of the first cylindrical portion, a female screw defined on the inner circumferential surface of the second cylindrical portion into which the male screw is screwed, and a second cover support portion that supports the blade cover from a second direction opposite to the first direction.

2. The work machine according to claim 1, wherein the first cover support portion and the second cover support portion each support the blade cover over substantially the entire circumference of the cover rotation axis.

3. The system further includes a bearing that rotatably supports the output shaft, The first member further includes a first bearing contact portion that contacts the bearing from the first direction, The work machine according to claim 1, wherein the second member further includes a second bearing contact portion that contacts the bearing from the second direction.

4. The work machine according to claim 3, wherein, when viewed from a direction perpendicular to the cover rotation axis, the male screw, the female screw, and the bearing overlap each other.

5. The work machine according to claim 1, wherein an elastic member is provided between the first cover support and the blade cover, and between the second cover support and the blade cover, at least one of these locations.

6. The output shaft is provided with a rotating blade holding mechanism that holds the rotating blade so that the rotating blade is fixed to the output shaft, The work machine according to claim 1, wherein, when viewed from a direction perpendicular to the rotation axis of the output shaft, the outer circumferential surface of the portion of the cover holding mechanism located between the rotating blade and the blade cover is retracted radially inward from the rotation axis of the output shaft compared to the outer circumferential surface of the rotating blade holding mechanism.

7. The work machine according to claim 1, wherein at least one of the first member and the second member has a polygonal prism shape with its central axis aligned with the cover rotation axis.

8. An implement according to any one of claims 1 to 7, wherein at least one of the first member and the second member is made of an aluminum alloy.

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