Work equipment

Abstract

To reduce costs.SOLUTION: An electric cutting machine 10 is configured so that an inner case 40 includes a box-shaped case main body 42 opened upward and a case cover 44 blocking an opening part 42M of the case main body 42. A driving mechanism 70, housed in the inner case 40, is arranged so as not to protrude upward from the opening part 42M of the case main body 42. This enables the case cover 44 to be formed in a flat plate-shape with a vertical direction as a plate thickness direction, so that the opening part 42M of the case cover 44 can be blocked. Thereby, the case cover 44 can be formed by applying press processing (die-cut) to a metal plate material. This can reduce costs of the case cover 44 and the inner case 40, more in comparison with a case where the case cover 44 is manufactured by casting, for instance.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] The saber saw (working machine) described in Patent Document 1 below is configured to include a gear housing that forms the outer shell of the saber saw, a main body case housed in the gear housing, a gear unit housed in the main body case, and a plunger connected to the gear unit. A blade (tool bit) is attached to the front end of the plunger. The driving force of the motor is transmitted to the plunger via the gear unit, causing the plunger to move back and forth together with the blade. This allows cutting to be performed on the workpiece. In other words, the gear unit and plunger for operating the tool bit are configured as a drive mechanism for operating the tool bit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-209455 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in the drive mechanism of the saber saw (working machine), the main body case that houses the drive mechanism is composed of two case members divided vertically. These case members are formed in a concave shape that opens inward in the vertical direction, and are formed with a relatively complex shape to accommodate each component of the drive mechanism. For this reason, these case members are generally formed by casting. This tends to increase the costs of the main body case and the working machine. Therefore, it is desirable to have a cost-reducing configuration for the working machine.

[0005] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a work machine that can reduce costs. [Means for solving the problem]

[0006] One or more embodiments of the present invention comprise: a drive source; an output section extending in the front-rear direction, holding the tool bit and driven by the drive source; connected to the drive source, the output unit and a case that houses the drive mechanism, To accommodate the drive mechanism therein, With an opening that opens to the side an insertion portion that is open to the front and through which a part of the output portion is inserted; a box-shaped case body having It is a metal plate-shaped component formed by press working, a cover that closes the opening, and the drive mechanism , disposed inside a space defined by the case body and the cover, than the opening upper side The work machine is positioned so as not to protrude into the

[0007] One or more embodiments of the present invention comprise: The case body is formed by metal casting. It is a work machine.

[0008] One or more embodiments of the present invention comprise: the drive mechanism has a guide portion that operably supports the output portion, and the cover restricts upward movement of the guide portion; It is a work machine.

[0009] One or more embodiments of the present invention comprise: The output portion is reciprocated in the front-rear direction by the drive source, and the guide portion slidably supports the output portion. It is a work machine.

[0010] One or more embodiments of the present invention comprise: the cover includes a fastening member that covers a hole formed in the cover, and the fastening member that is connected to the case body prevents the cover from being separated from the case body. It is a work machine.

[0011] One or more embodiments of the present invention comprise: The drive source reciprocates the tool bit in the front-rear direction using the drive mechanism, and has a vibration reduction mechanism that reduces vibrations in the front-rear direction that occur when the tool bit is operated by the drive mechanism, and the vibration reduction mechanism includes a counterweight that reciprocates in the front-rear direction using the drive source, and a weight support part that is housed in the case body and supports the counterweight so that it can reciprocate, and the cover restricts upward movement of at least one of the counterweight and the weight support part. It is a work machine.

[0012] One or more embodiments of the present invention comprise: A rolling element that reciprocates in the front-rear direction due to the movement of the counterweight is disposed between the cover and the counterweight, and the counterweight is supported by the cover via the rolling element, thereby restricting upward movement of the counterweight. It is a work machine.

[0013] One or more embodiments of the present invention comprise: The case body is formed with a communication portion that is open downward, and the communication portion is closed by the drive source. It is a work machine.

[0014] One or more embodiments of the present invention comprise: a drive source; at least one reciprocating body extending along a front-to-rear direction and reciprocated in the front-to-rear direction by the drive source; at least one support section supporting the reciprocating body so that the reciprocating body can reciprocate; a transmission mechanism transmitting power from the drive source to the reciprocating body; and a case accommodating the transmission mechanism, wherein the reciprocating body includes an output section that holds a tool bit and is driven to reciprocate by the drive source; the case is configured to include a box-shaped case body having an opening that is open to the upper side for accommodating the transmission mechanism therein and an insertion section that is open to the front side and through which a part of the output section is inserted; and a cover that is a metal plate-like member formed by press working and closes the opening, wherein the transmission mechanism is disposed within a space defined by the case body and the cover and is disposed so as not to protrude above the opening, and at least one of the at least one reciprocating body and the at least one support section is restricted from moving upward by the cover. is.

[0015] One or more embodiments of the present invention comprise: a gear that rotates about an axis in the vertical direction and transmits the power of the drive source to the reciprocating body, and the cover restricts the gear from moving upward; It is a work machine. [Effects of the Invention]

[0017] One or more embodiments of the present invention may result in reduced costs. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a side view showing the electric cutting machine according to the embodiment, as viewed from the right side. [Figure 2] 2 is a side view showing the inside of the electric cutter shown in FIG. 1 as viewed from the right side. [Figure 3] 3 is a vertical cross-sectional view showing the inside of the inner case shown in FIG. 2 as viewed from the right side. [Figure 4] 4 is a cross-sectional view (cross-sectional view taken along line 4-4 in FIG. 3) showing the inside of the rear part of the inner case shown in FIG. 3 as seen from the front side. [Figure 5] 5 is a cross-sectional view (cross-sectional view taken along line 5-5 in FIG. 2) seen from the rear side, showing a fastened and fixed state between the case cover and the case body at the rear end of the inner case shown in FIG. 2. [Figure 6] 3 is a perspective view of the inner case shown in FIG. 2 with the case cover removed from the case body, as viewed obliquely from the front left. [Figure 7] 7 is a perspective view showing a case body of the inner case shown in FIG. 6, seen obliquely from the front left. [Figure 8] 7 is a plan view showing the drive mechanism shown in FIG. 6 housed in the case body with the vibration reduction mechanism removed. FIG. [Figure 9] 4 is an exploded perspective view showing a reciprocating mechanism part of the drive mechanism shown in FIG. 3, seen obliquely from the front left. FIG. [Figure 10] 4 is an exploded perspective view showing a vibration reduction mechanism of the drive mechanism shown in FIG. 3, seen obliquely from the front left. DETAILED DESCRIPTION OF THE INVENTION

[0019] An electric cutting machine 10 as a work machine according to this embodiment will be described below with reference to the drawings. Note that the arrows UP, FR, and RH shown as appropriate in the drawings indicate the upper side, front side, and right side of the electric cutting machine 10, respectively. In the following description, when the up-down, front-rear, and left-right directions are used, they refer to the up-down, front-rear, and left-right directions of the electric cutting machine 10 unless otherwise specified. The up-down direction corresponds to the first direction in the present invention, the front-rear direction corresponds to the second direction in the present invention, and the left-right direction corresponds to the third direction in the present invention.

[0020] The electric cutter 10 is configured as an electric tool that cuts materials such as pipes. As shown in Figures 1 and 2, the electric cutter 10 includes a housing 20 that forms the outer shell of the electric cutter 10, an inner case 40 that is housed and fixed within the housing 20, a motor 60 that is a drive source mounted in the inner case 40, and a drive mechanism 70 that is housed in the inner case 40. Each component of the electric cutter 10 will be described below.

[0021] (About Housing 20) The housing 20 is formed as a whole in a generally hollow cylindrical shape extending in the front-rear direction. The housing 20 is composed of two housing members divided in the left-right direction, and the left and right housing members are assembled to form the housing 20. The housing 20 is composed of a front housing portion 20A that forms the front portion of the housing 20 and a handle housing portion 20B that forms the rear end of the housing 20 and serves as a handle. The front housing portion 20A extends in the front-rear direction, and the rear end of the front housing portion 20A is bent downward. The handle housing portion 20B extends in the up-down direction, and both vertical ends of the handle housing portion 20B are bent forward and connected to the rear end of the front housing portion 20A. During cutting, an operator grips the handle housing portion 20B to perform the cutting process.

[0022] A trigger 22 is provided at the upper end portion of the handle housing portion 20B. The trigger 22 protrudes forward from the handle housing portion 20B and can be pulled rearward. A switch mechanism portion 24 is provided in the handle housing portion 20B behind the trigger 22. The switch mechanism portion 24 has a switch (not shown) that is operated by the trigger 22, and the switch is electrically connected to a control portion 26. The control portion 26 is provided at the lower end portion on the rear end side of the front housing portion 20A. An output signal corresponding to the operation of the trigger 22 is output from the switch to the control portion 26.

[0023] A battery 28 is detachably attached to the rear side of the lower end of the handle housing portion 20B. The battery 28 is electrically connected to the control portion 26 and a motor 60 (described later), and power is supplied from the battery 28 to the control portion 26 and the motor 60.

[0024] (About Inner Case 40) 2 to 8, the inner case 40 is formed in a generally rectangular box shape that extends in the front-to-rear direction as a whole. The inner case 40 is accommodated in the upper part of the front housing portion 20A and is fixed to the housing 20 by being sandwiched from the outside in the left-right direction between housing members that constitute the housing 20. The inner case 40 is configured to include a case main body 42 and a case cover 44 that serves as a cover, and the case cover 44 is fastened and fixed to the case main body 42.

[0025] (Regarding the case body 42) The case body 42 is made of metal and is formed by casting. The case body 42 is generally formed in a generally rectangular box shape that extends in the front-rear direction and is open upward. A gear accommodating portion 42A (see FIG. 4) that accommodates a gear 71 (described later) is formed in the bottom of the rear portion of the case body 42. The gear accommodating portion 42A is formed in a two-stage stepped cylindrical shape with the vertical axis as the axial direction. Specifically, the gear accommodating portion 42A includes an upper accommodating portion 42A1 that forms the upper portion of the gear accommodating portion 42A, an intermediate accommodating portion 42A2 that forms the vertical intermediate portion of the gear accommodating portion 42A, and a lower accommodating portion 42A3 that forms the lower portion of the gear accommodating portion 42A. The diameter of the intermediate accommodating portion 42A2 is set larger than the diameter of the lower accommodating portion 42A3, and the diameter of the upper accommodating portion 42A1 is set larger than the diameter of the intermediate accommodating portion 42A2. The upper accommodating portion 42A1 protrudes upward beyond the bottom wall of the case body 42. Both left and right side portions of the upper accommodating portion 42A1 protrude outward beyond the side walls of the case body 42 in the left and right directions, thereby constituting the outer shell of the case body 42. A circumferential ball groove 42B (see FIGS. 3 and 4) is formed in the outer periphery of the lower surface of the intermediate accommodating portion 42A2, and the ball groove 42B is formed around the entire circumferential circumference of the intermediate accommodating portion 42A2. A plurality of rolling balls 50 are provided inside the ball groove 42B, and the plurality of rolling balls 50 are arranged side by side along the circumferential direction of the ball groove 42B. The upper ends of the rolling balls 50 are positioned above the bottom surface of the upper accommodating portion 42A1 and are disposed within the upper accommodating portion 42A1.

[0026] A shaft accommodating portion 42C (see FIG. 3) is formed at the bottom of the case main body 42, behind the gear accommodating portion 42A, as a communication portion for accommodating a portion of a drive shaft 61 of the motor 60 (described later). The shaft accommodating portion 42C is formed in a generally stepped cylindrical shape with its axial direction extending vertically, and the diameter of the upper portion of the shaft accommodating portion 42C is set smaller than the diameter of the lower portion of the shaft accommodating portion 42C. The interior of the shaft accommodating portion 42C is penetrated vertically, and the interior and exterior of the case main body 42 are communicated by the shaft accommodating portion 42C. In addition, the shaft accommodating portion 42C is disposed so as to overlap the rear end portion of the gear accommodating portion 42A in a plan view, and the interior of the shaft accommodating portion 42C is communicated with the interior of the upper accommodating portion 42A1.

[0027] As shown in FIGS. 7 and 8, a pair of left and right protrusions 42D are formed on the upper rear portion of the case main body 42, protruding outward in the left-right direction. The protrusions 42D protrude on both front-rear directions relative to the gear accommodating portion 42A, and the upper ends of the upper accommodating portions 42A1 of the gear accommodating portion 42A are connected to the bottom walls 42D1 of the protrusions 42D. The bottom walls 42D1 of the left and right protrusions 42D are connected to each other at the rear of the gear accommodating portion 42A. Positioning pieces 42A4 are formed at the front and rear ends of the upper accommodating portion 42A1 of the gear accommodating portion 42A, and the positioning pieces 42A4 protrude above the upper accommodating portions 42A1 and the bottom walls 42D1 of the protrusions 42D. Rear fixing bosses 42E are formed at the outer ends of the bottom walls 42D1 of the protrusions 42D in the front-rear direction. The rear fixed boss 42E is formed in a generally cylindrical shape with its axis extending in the vertical direction and protruding upward from the bottom wall 42D1 (see FIG. 5), with the upper end face of the rear fixed boss 42E located below the upper end face of the case main body 42. A female thread is formed on the inner periphery of the rear fixed boss 42E. The rear fixed boss 42E is formed with a pair of left and right fixing ribs 42E1, which extend from the outer peripheries on both left and right sides of the rear fixed boss 42E toward the inside in the front-to-rear direction of the protruding portion 42D.

[0028] A pair of front and rear installation portions 42F for installing a guide metal 80 (described later) are formed on the bottom walls 42D1 of the pair of overhanging portions 42D, respectively. The installation portions 42F are formed in a generally circular plate shape with the thickness direction being the up-down direction, protrude upward from the bottom wall 42D1, and are disposed inside the overhanging portion 42D in the front-rear direction with respect to the rear fixing boss 42E. Furthermore, a plurality of positioning ribs 42G (five in this embodiment) are integrally formed on each of the pair of overhanging portions 42D between the pair of front and rear fixing bosses 42E. The positioning ribs 42G are formed in a generally rectangular column shape, extend upward from the bottom wall 42D1 of the overhanging portion 42D, and are connected to the left and right side walls of the overhanging portion 42D. The multiple positioning ribs 42G are arranged side by side at equal intervals in the front-rear direction.

[0029] A pair of left and right front fixed bosses 42H are formed on the front end of the case body 42. The front fixed bosses 42H are formed in a generally cylindrical shape with their axial direction extending up and down, and extend upward from the bottom wall of the case body 42. The front fixed bosses 42H are connected to the left and right side walls of the case body 42, and the upper end surfaces of the front fixed bosses 42H are disposed flush with the upper end surface of the case body 42. An internal thread is formed on the inner periphery of the front fixed boss 42H.

[0030] An insertion portion 42J is formed in the front wall of the case body 42, through which a plunger 82 (described later) is inserted. The insertion portion 42J is formed as a groove that opens upward and penetrates in the front-to-rear direction. A motor holding portion 42K is formed in the rear end of the case body 42 as a holding portion for holding a motor 60 (described later). The motor holding portion 42K is formed in a generally rectangular cylindrical shape that protrudes downward from the case body 42 and is arranged coaxially with the shaft accommodating portion 42C, and notches 42K1 that open downward are formed in each side wall of the motor holding portion 42K. In other words, the motor holding portion 42K can be said to be composed of four pillar portions 42K2.

[0031] An attachment piece 42L is integrally formed with the lower end of the front wall of the case body 42. The attachment piece 42L is formed in a generally rectangular plate shape with its thickness direction extending up and down, and extends forward from the front wall of the case body 42. As shown in FIGS. 3 and 6, a fixing plate 52 is provided below the attachment piece 42L. The fixing plate 52 is formed in a generally U-shaped plate shape that is open upward when viewed from the front, and is fastened and fixed to the attachment piece 42L via a stay 54. As shown in FIG. 6, a base 56 is provided at the front end of the fixing plate 52. The fixing plate 52 is formed in a generally rectangular frame shape with its longitudinal direction extending up and down when viewed from the front, and the lower end portion of the base 56 is rotatably connected to the front end of the fixing plate 52 with its axial direction extending left and right.

[0032] (About case cover 44) As shown in FIG. 6 , the case cover 44 is made of a metal plate and formed by press working (punching). The case cover 44 is formed in a generally rectangular flat plate shape with its thickness extending in the vertical direction and its length extending in the front-rear direction. The outer shape of the case cover 44 is formed to match the outer shape of the upper end of the case main body 42 in a plan view. Fixing holes 44A are formed through the outer periphery of the case cover 44 at positions corresponding to the rear fixing boss 42E and the front fixing boss 42H of the case main body 42. Fixing bolts BL1 serving as fastening members are inserted from above into the fixing holes 44A corresponding to the rear fixing boss 42E and screwed into the inner periphery of the rear fixing boss 42E, and fixing bolts BL2 serving as fastening members are inserted from above into the fixing holes 44A corresponding to the front fixing boss 42H and screwed into the inner periphery of the front fixing boss 42H. As a result, the case cover 44 is fixed to the case body 42, and the upper opening 42M of the case body 42 is closed by the case cover 44.

[0033] A packing 46 is provided between the outer periphery (lower surface) of the case cover 44 and (the upper surface of) the case main body 42. The packing 46 is made of an elastic material such as rubber and is formed in a frame shape with its thickness in the vertical direction, and the thickness of the packing 46 is set to be relatively thin. As a result, the opening 42M of the case main body 42 is sealed and closed by the packing 46 and the case cover 44.

[0034] 5, a fixing sleeve 48 serving as a fixing device is provided between the case cover 44 (packing 46) and the rear fixed boss 42E. The fixing sleeve 48 is formed in a generally cylindrical shape with its axial direction extending in the vertical direction, and a fixing bolt BL1 is inserted through the fixing sleeve 48. In other words, the case cover 44 is fastened and fixed to the rear fixed boss 42E via the fixing sleeve 48. A step 48A is formed in the vertical middle of the outer periphery of the fixing sleeve 48, and the diameter of the upper part of the fixing sleeve 48 is set larger than the diameter of the lower part of the fixing sleeve 48.

[0035] (Regarding motor 60) As shown in FIGS. 2 and 3 , the motor 60 is configured as a brushless motor and is disposed below the rear end of the case body 42. The motor 60 has a drive shaft 61 as a transmission member. The drive shaft 61 extends vertically, and a gear portion 61A constituted by a helical gear is formed at the upper end of the drive shaft 61. The upper end portion of the drive shaft 61 is accommodated in the shaft accommodating portion 42C of the case body 42, and the upper end of the drive shaft 61 protrudes upward from the shaft accommodating portion 42C and is disposed within the rear end of the gear accommodating portion 42A. The upper end portion of the drive shaft 61 is rotatably supported by a motor bearing 65 fixed to the lower portion of the shaft accommodating portion 42C. The lower end portion of the drive shaft 61 is rotatably supported by a motor bearing 66, which is fixed to a bearing holder 67 assembled to the case body 42.

[0036] The bearing holder 67 has a holder base 67A and four arm portions 67B. The holder base 67A is formed in a generally rectangular plate shape with its thickness extending vertically. A bearing holding portion 67C that protrudes downward and is open upward is formed in the approximate center of the holder base 67A. The motor bearing 66 is fitted into the bearing holding portion 67C and fixed to the bearing holder 67. The arm portions 67B extend upward from the four corners of the holder base 67A. The upper end portions of the arm portions 67B are disposed inside the motor holding portion 42K of the case body 42 and are assembled to the motor holding portion 42K.

[0037] The rotor 62 and stator 63 of the motor 60 are disposed radially outward from the lower part of the drive shaft 61 and are disposed inside the motor holder 42K. A fan 68 is provided on the upper end portion of the drive shaft 61 so as to be integrally rotatable, and is disposed adjacent to the lower side of the motor bearing 65. The fan 68 is configured as a centrifugal fan.

[0038] (Regarding the drive mechanism 70) 3 and 6, the drive mechanism 70 is housed inside the inner case 40. The drive mechanism 70 includes a gear mechanism 70A as a first drive mechanism, a reciprocating mechanism 70B as a second drive mechanism, and a vibration reduction mechanism 70C as a third drive mechanism.

[0039] (Regarding the gear mechanism 70A) As shown in FIGS. 3 and 4 , the gear mechanism 70A is primarily configured with a gear 71 serving as a first drive member. The gear 71 is formed in a generally circular disk shape with its thickness extending vertically. The gear 71 is housed in the upper housing portion 42A1 of the gear housing portion 42A and is placed above the rolling balls 50. A gear hole 71A is formed through the center of the gear 71. The upper end of a gear shaft 72, whose axial direction is the vertical direction, is inserted into the gear hole 71A, and the gear hole 71A is rotatably supported by the gear shaft 72 via a needle bearing 73. The lower portion of the gear shaft 72 is supported by a cylindrical bushing 74, which is provided inside the intermediate housing portion 42A2 and the lower housing portion 42A3 of the gear housing portion 42A. As a result, the gear 71 is accommodated in the gear accommodating portion 42A so as to be rotatable about its axial direction in the vertical direction, while being supported by the rolling balls 50 from below.

[0040] A gear portion 71B formed by a helical gear is formed on the outer periphery of the gear 71, and the gear portion 71B meshes with a gear portion 61A of the drive shaft 61 of the motor 60. As a result, when the motor 60 is operating, the gear 71 rotates, and a vertical thrust force is generated in the gear 71 due to the meshing of the gear portions 61A and 71B formed by the helical gears. Specifically, when a blade 95 (described later) is moved rearward by the drive mechanism 70, a downward thrust force acts on the gear 71, and the rolling balls 50 receive the thrust force.

[0041] A crank pin 75 serving as a connecting part is provided to rotate integrally with the gear 71. The crank pin 75 is formed in a generally cylindrical shape with its axial direction extending in the vertical direction, is disposed at a position eccentric to the rotation axis of the gear 71, and protrudes upward from the gear 71. A cylindrical sleeve 77 is rotatably provided on the crank pin 75 via a needle bearing 76, and the upper end of the crank pin 75 protrudes upward beyond the needle bearing 76 and the sleeve 77.

[0042] (Regarding the reciprocating mechanism 70B) 3 to 6, 8, and 9, the reciprocating mechanism 70B is accommodated in the case body 42 above the gear mechanism 70A. The reciprocating mechanism 70B includes guide metals 80 as a pair of left and right receiving members, and a plunger 82 as a second driving member.

[0043] (About Guide Metal 80) The pair of left and right guide metals 80 are made of a sintered material and are impregnated with a lubricant. The guide metal 80 is formed in a generally rectangular plate shape with the longitudinal direction being the front-rear direction and the thickness direction being the up-down direction, and is formed in a generally U-shape that opens inward in the left-right direction when viewed from the front-rear direction. That is, a slit 80A serving as a second receiving portion is formed in the middle portion of the guide metal 80 in the up-down direction, and the slit 80A is formed in the shape of a groove that opens inward in the left-right direction and penetrates in the front-rear direction. Furthermore, the guide metal 80 has a lower surface 80B and an upper surface 80C serving as first receiving portions that are arranged along a plane perpendicular to the up-down direction.

[0044] 4 and 8, the guide metal 80 is housed in the protruding portion 42D of the case main body 42, and the underside 80B of the guide metal 80 is mounted on the mounting portion 42F of the protruding portion 42D. The guide metal 80 is disposed between a pair of front and rear fixed bosses 42E, and the position of the guide metal 80 in the front-rear direction is determined by a fixing rib 42E1 on the rear fixed boss 42E. The guide metal 80 is also disposed between a positioning piece 42A4 and a positioning rib 42G of the case main body 42, and the position of the guide metal 80 in the left-right direction is determined by the positioning piece 42A4 and the positioning rib 42G.

[0045] A relief recess 80D (see FIG. 8 ) is formed in the inner lateral portion of the front-rear intermediate portion of the guide metal 80. In plan view, the relief recess 80D is formed in a generally arc-shaped recess centered on the rotation axis of the gear 71, and is open inward in the lateral direction and penetrates vertically. The edges of the relief recess 80D in the guide metal 80 are located adjacent to the upper sides of the outer periphery of the gear 71 on both lateral sides, forming a predetermined vertical gap between the guide metal 80 and the gear 71. As a result, when an upward thrust force acts on the gear 71 during rotation, causing the gear 71 to move upward, the lower surface 80B of the guide metal 80 receives the thrust force and restricts the upward movement of the gear 71. At this time, the outer periphery of the gear 71 slides on the lower surface 80B of the guide metal 80. That is, the guide metal 80 is configured as a stop member that receives the gear 71 moving upward (to one side in the thrust direction) and limits the upward movement of the gear 71. Also, the lower surface 80B of the guide metal 80 is configured as a receiving surface that receives the gear 71, and is also configured as a positioning surface that determines the vertical position of the guide metal 80 (the rear end of the reciprocating mechanism part 70B).

[0046] (Regarding plunger 82) As shown in FIGS. 3, 4, 8, and 9, the plunger 82 is formed in an elongated shape extending in the front-rear direction. The plunger 82 includes a connector 83 that forms the rear portion of the plunger 82 and an output shaft 84 that forms the front portion of the plunger 82. The connector 83 is formed in a generally T-shaped plate shape with its thickness direction in the up-down direction. Specifically, the connector 83 includes a rear connector portion 83A that extends in the left-right direction and a front connector portion 83B that extends forward from a left-right intermediate portion of the rear connector portion 83A. Both left-right ends of the rear connector portion 83A are inserted into slits 80A of the guide metals 80 so as to be movable in the front-rear direction, and the connector 83 is supported by the pair of left and right guide metals 80 so as to be movable in the front-rear direction. The rear connector portion 83A is disposed adjacent to the inside of the bottom surface (outer surface in the left-right direction) of the slit 80A in the left-right direction. That is, the guide metal 80 is configured as a guide member that receives the operating connector 83 from both the top and bottom sides and guides the movement of the connector 83 in the front-to-rear direction. The guide metal 80 is also configured as a support member that supports the sliding of the connector 83 that moves in the front-to-rear direction. That is, the guide metal 80 is a sliding bearing.

[0047] A connecting hole 83C is formed through the rear connector portion 83A, and the connecting hole 83C is formed as an elongated hole with its longitudinal direction extending in the left-right direction. The crank pin 75, needle bearing 76, and sleeve 77 of the gear 71 are inserted into the connecting hole 83C so as to be movable in the left-right direction and engageable in the front-rear direction. As a result, the rotational force of the gear 71 is converted by the crank pin 75 including the sleeve 77, causing the connector 83 (plunger 82) to reciprocate in the front-rear direction. The crank pin 75 (sleeve 77) is disposed between a pair of left and right guide metals 80, and during rotation of the gear 71, the relief recesses 80D of the guide metals 80 suppress interference between the sleeve 77 and the guide metals 80. A material relief hole 83D is formed through the front connector portion 83B, except for the front end portion, and the material relief hole 83D is formed as a substantially rectangular shape extending in the front-rear direction.

[0048] The output shaft 84 is formed in a generally cylindrical shape with a bottom that is open to the front. The rear end of the output shaft 84 engages with the front end of the connector 83 in the front-rear direction and is connected to the front end of the connector 83 by a plunger sleeve 85 so as not to be able to move relatively thereto. The front end portion of the output shaft 84 is supported by a pair of upper and lower rollers 90 in a roller unit 87 provided at the front end of the case body 42.

[0049] The roller unit 87 includes a roller holder 88, a pair of upper and lower roller shafts 89, and a pair of upper and lower rollers 90. The roller holder 88 is formed in a generally U-shaped plate shape that is open to the rear in a plan view, and is disposed between the left and right front fixed bosses 42H of the case body 42 and assembled to the case body 42. The roller shaft 89 is suspended between the left and right side walls of the roller holder 88 with the left-right direction as its axial direction. The roller shafts 89 are respectively provided at the top and bottom of the roller holder 88. The rollers 90 are formed in a generally circular plate shape with the left-right direction as their thickness direction, and the central portions of the rollers 90 are rotatably supported by the roller shafts 89. The output shaft 84 is disposed between the pair of upper and lower rollers 90 and is supported for rolling by the rollers 90. The front end of the roller 90 passes through a holder hole 88A formed in the front wall of the roller holder 88 and an insertion portion 42J of the case body 42, and protrudes forward from the front wall of the case body 42.

[0050] A blade mounting mechanism 92 is provided at the front end of the output shaft 84. The blade mounting mechanism 92 has a mounting core portion 93. The mounting core portion 93 is formed in a substantially stepped cylindrical shape with its axial direction extending in the front-to-rear direction, and the mounting core portion 93 is fixed to the output shaft 84 with its rear end inserted into the front end of the output shaft 84.

[0051] 3 and 6, a dust sleeve 30 is provided at the front end of the output shaft 84. The dust sleeve 30 is formed in a generally cylindrical shape with a bottom that is open to the front. The front end of the output shaft 84 passes through the bottom of the dust sleeve 30, and the blade attachment mechanism 92 is disposed within the dust sleeve 30 of the housing 20. The front end of the dust sleeve 30 is assembled to the housing 20, and the dust sleeve 30 is disposed within the front end of the housing 20.

[0052] A blade 95 (see FIG. 3 ) serving as an accessory tool is attached to the blade attachment mechanism 92. The blade 95 is formed in a generally elongated plate shape with its thickness in the left-right direction and extending in the front-rear direction, and the rear end of the blade 95 is attached to the blade attachment mechanism 92. When the blade 95 is attached, it extends forward from the dust sleeve 30 and is disposed on the front side of the housing 20 and within the base 56. A cutting edge 95A is formed at the lower end of the blade 95, and the cutting edge 95A is formed over the entire length of the blade 95. As a result, when the drive mechanism 70 is operated, the blade 95 reciprocates in the front-rear direction together with the output shaft 84.

[0053] Furthermore, the reciprocating mechanism 70B is disposed above the vertical center portion 20B1 of the handle housing portion 20B in the housing 20. Specifically, the vertical center portion 20B1 of the handle housing portion 20B is disposed below the axis CL of the output shaft 84 of the reciprocating mechanism 70B (see FIG. 2).

[0054] (Regarding the vibration reduction mechanism 70C) 3, 4, 6, and 10, the vibration reduction mechanism 70C is housed above the reciprocating mechanism 70B in the rear part of the case body 42. The vibration reduction mechanism 70C includes a pair of left and right base members 100, a pair of left and right guide members 102, a ring member 104 as a third drive member, and a counterweight 108.

[0055] The base member 100 is disposed at the lower end of the vibration reduction mechanism 70C and functions as a base for the vibration reduction mechanism 70C. The base member 100 is formed in a generally rectangular plate shape with its thickness extending in the up-down direction and its length extending in the front-rear direction. The base member 100 is disposed above the guide metal 80 (see FIGS. 3, 4, and 10), with the front and rear ends of the base member 100 disposed adjacent to the upper sides of the rear fixed boss 42E (see FIGS. 3 and 5). Positioning recesses 100A (see FIGS. 5 and 10) are formed penetrating the base member 100 in the up-down direction at both ends in the front-rear direction. The positioning recess 100A is formed in a concave shape that opens outward in the front-rear direction and is formed in an arc shape centered on the axis of the fixed sleeve 48 in a plan view. Specifically, the radius of the positioning recess 100A is generally the same as the radius of the lower part of the fixed sleeve 48. A portion of the lower part of the fixing sleeve 48 is fitted into the positioning recess 100A, and the position of the base member 100 is determined by the fixing sleeve 48. The step portion 48A of the fixing sleeve 48 is disposed adjacent to the upper side of the edge of the positioning recess 100A. This allows the fixing sleeve 48 to fix the base member 100 to the case main body 42.

[0056] As described above, the base member 100 is disposed adjacent to the upper side of the guide metal 80. Therefore, the guide metal 80 is sandwiched vertically between the base member 100 and the installation portion 42F of the case body 42, and is fixed to the case body 42. In other words, the base member 100 constitutes the base of the vibration reduction mechanism 70C, and is also configured as a stopper component that limits the upward movement of the guide metal 80 (reciprocating mechanism 70B) and the gear 71 (gear mechanism 70A).

[0057] A base accommodating portion 100B is formed on the upper surface of the base member 100, except for the front and rear ends. The base accommodating portion 100B is recessed downward from the front and rear ends of the base member 100 and penetrates in the left-right direction. A guide recess 100C (see FIG. 10) is formed on the left-right inner side of the intermediate portion of the base member 100 in the front-rear direction. The guide recess 100C is formed in an arc-shaped recess centered on the axis of the gear 71 in plan view and opens inward in the left-right direction. More specifically, the radius of the guide recess 100C is set larger than the radius of the relief recess 80D of the guide metal 80, and the guide recess 100C is positioned radially outward of the relief recess 80D in plan view.

[0058] The pair of left and right guide members 102 extend in the front-rear direction and are formed into a generally L-shaped plate shape when viewed from the front-rear direction. Specifically, the guide members 102 include a bottom wall 102A constituting the lower end of the guide members 102 and a side wall 102B extending upward from the outer left-right end of the bottom wall 102A. The bottom wall 102A of the guide members 102 is fitted into a base accommodating portion 100B of the base member 100, and the guide members 102 are placed on the base member 100. Movement of the base member 100 in the front-rear direction is restricted by the front and rear end surfaces of the base accommodating portion 100B of the base member 100. A ball groove portion 102C extending along the front-rear direction is formed on the inner left-right surface of the side wall 102B of the guide members 102. When viewed from the front-rear direction, the ball groove portion 102C is formed into a generally semicircular shape that opens inward in the left-right direction and penetrates in the front-rear direction.

[0059] The ring member 104 is formed in a substantially annular plate shape with its thickness extending in the vertical direction. The ring member 104 is disposed between a pair of base members 100. Specifically, both left and right sides of the ring member 104 are disposed within the guide recess 100C of the base member 100, and the outer periphery of the ring member 104 is disposed adjacent to the radially inner side of the guide recess 100C. As a result, the ring member 104 is disposed coaxially with the gear 71 above the gear 71. Furthermore, both left and right sides of the ring member 104 are disposed between the guide metal 80 and the guide member 102, and the guide metal 80 and the guide member 102 restrict the movement of the ring member 104 in the vertical direction (see FIG. 4). More specifically, both left and right sides of the ring member 104 are placed on the upper side of the guide metal 80. That is, the guide metal 80 is configured as a stop member that supports the ring member 104 from below with its upper surface 80C and restricts the downward movement of the ring member 104.

[0060] A pair of ring connectors 104A are integrally formed on the inner periphery of the ring member 104. The pair of ring connectors 104A protrude radially inward from the ring member 104 and are spaced 180 degrees apart circumferentially of the ring member 104. One of the ring connectors 104A has a connector hole 104B formed therethrough in the vertical direction, and the upper end of the crank pin 75 of the gear 71 is inserted into the connector hole 104B so as to be rotatable relative to the ring member 104 (see FIG. 3). This connects the ring member 104 and the gear 71 so as to be rotatable together. When the ring member 104 rotates, the outer periphery of the ring member 104 is guided by the guide recess 100C of the guide member 102 and slides on the upper surface 80C of the guide metal 80. In other words, the guide metal 80 also functions as a support member that supports the ring member 104 in a sliding manner. The other ring connecting portion 104A of the ring member 104 is provided with a crank pin 106 whose axial direction is the up-and-down direction. The crank pin 106 protrudes upward from the ring member 104.

[0061] The counterweight 108 is formed in a generally rectangular plate shape with the thickness direction extending up and down and the length direction extending forward and backward. A pair of left and right weight flanges 108A that protrude outward in the left-right direction are formed in the middle of the counterweight 108 in the forward and backward direction. The counterweight 108 is disposed above the ring member 104 with the weight flanges 108A disposed above the bottom wall 102A of the guide member 102.

[0062] A first ball groove portion 108B extending in the front-rear direction is formed on the side surface of the weight flange portion 108A, and the first ball groove portion 108B is formed in a substantially semicircular shape that opens outward in the left-right direction in a cross section viewed from the front-rear direction. The first ball groove portion 108B is arranged opposite the ball groove portion 102C of the guide member 102 in the left-right direction (see FIG. 4). A plurality of first rolling balls 110 (three in this embodiment) serving as first balls are arranged in the first ball groove portion 108B and the ball groove portion 102C, and the counterweight 108 is supported by the first rolling balls 110 in a rolling manner. This allows the counterweight 108 to slide in the front-rear direction.

[0063] Note that multiple (three in this embodiment) biasing sleeves 112 are provided between the guide member 102 and the side wall of the protruding portion 42D of the case main body 42 (see FIGS. 4 and 6). The biasing sleeves 112 are made of an elastic material such as rubber and are formed in a generally cylindrical shape with the vertical direction as the axial direction. The biasing sleeves 112 are disposed between the guide member 102 and the protruding portion 42D in a state where they are compressed in the left-right direction, and bias the guide member 102 inward in the left-right direction. Therefore, the first rolling balls 110 abut against the inner circumferential surfaces of the first ball groove portion 108B and the ball groove portion 102C.

[0064] A weight connecting hole 108C is formed through the counterweight 108 in the middle in the front-rear direction. The weight connecting hole 108C is formed as an elongated hole with the longitudinal direction in the left-right direction. The upper end of the crank pin 106 of the ring member 104 is inserted into the weight connecting hole 108C so as to be relatively movable in the left-right direction and engageable in the front-rear direction. As a result, when the ring member 104 rotates, the counterweight 108 moves back and forth in the front-rear direction. Specifically, when the gear 71 and the ring member 104 rotate, the counterweight 108 moves back and forth in the front-rear direction in the opposite phase to the plunger 82.

[0065] A pair of front and rear second ball groove portions 108D are formed in the upper surface of the counterweight 108 in the center in the left-right direction, and the second ball groove portions 108D are located outward in the front-rear direction from the weight connecting holes 108C. The second ball groove portions 108D extend in the front-rear direction and are formed in a generally semicircular shape that is open upward in a cross section viewed from the front-rear direction. A plurality of second balls (three in this embodiment) serving as second rolling balls 114 are disposed in the second ball groove portions 108D, and the second rolling balls 114 abut against the lower surface of the case cover 44 and the inner circumferential surface of the second ball groove portions 108D. This allows the counterweight 108 to be supported by the second rolling balls 114 in a rolling manner.

[0066] In this embodiment, the upper ends of the second rolling balls 114 are positioned at the same position as the upper end of the case body 42 including the packing 46 and abut against the lower surface of the case cover 44. In other words, the second rolling balls 114 are set so as not to protrude beyond the upper end of the case body 42 including the packing 46. Here, each component constituting the drive mechanism 70 has a dimensional tolerance. Therefore, in order to ensure that the second rolling balls 114 abut against the lower surface of the case cover 44, the upper ends of the second rolling balls 114 may be made to protrude slightly beyond the upper end of the case body 42 including the packing 46, taking into account the dimensional tolerance of the components. In other words, in the present invention, the phrase "the drive mechanism 70 is housed so as not to protrude above the opening 42M of the case body 42" includes the case where the upper ends of the second rolling balls 114 protrude slightly beyond the upper end of the case body 42 including the packing 46. Furthermore, in the present invention, the phrase "the drive mechanism 70 is housed so as not to protrude above the opening 42M of the case body 42" means that the drive mechanism 70 is located below the end (upper end) of the case body 42 in a predetermined direction (upward), which has the opening 42M that opens in a predetermined direction (upward). In this case, the predetermined direction can also be referred to as the assembly direction of the case body 42 and the case cover 44. Note that the assembly direction of the case body 42 and the case cover 44 is not limited to the up-down direction. In other words, the upper surface of the case body 42 may be inclined relative to the front-rear or left-right direction, and the case cover 44 may be assembled to match that upper surface.

[0067] (Action and effect) Next, the operation and effects of the electric cutter 10 of this embodiment will be described.

[0068] In cutting with the electric cutter 10 configured as described above, the operator pulls the trigger 22, which causes the control unit 26 to operate the motor 60. This causes the gear 71 meshed with the gear portion 61A of the drive shaft 61 of the motor 60 to rotate. As a result, the plunger 82 of the reciprocating mechanism 70B connected to the crank pin 75 of the gear 71 reciprocates back and forth together with the blade 95. This causes the cutting of the material to be cut.

[0069] Furthermore, when the gear 71 rotates, the ring member 104, which is connected to the crank pin 75 of the gear 71, rotates integrally with the gear 71. As a result, the counterweight 108, which is connected to the crank pin 106 of the ring member 104, moves back and forth in the front-to-rear direction. The crank pins 75 and 106 are arranged 180 degrees apart around the circumferential direction of the ring member 104. Therefore, the back-to-back movement of the counterweight 108 is in the opposite phase to the back-to-back movement of the plunger 82 and the blade 95. As a result, the vibration reduction mechanism 70C acts as a dynamic vibration absorber, and vibrations generated by the back-to-back movement of the plunger 82 and the blade 95 are reduced by the vibration reduction mechanism 70C.

[0070] In the reciprocating mechanism 70B of the drive mechanism 70 of the electric cutter 10, the connector 83 of the plunger 82 is inserted into the slit 80A of the guide metal 80 so as to be movable in the front-rear direction. As a result, the guide metal 80 serves as a guide member that receives the connector 83 from both the top and bottom sides and guides the movement of the connector 83 in the front-rear direction. The guide metal 80 is also disposed adjacent to the upper side of the gear 71 constituting the gear mechanism 70A. As the gear 71 moves upward due to thrust force, the guide metal 80 receives the gear 71 from above and acts as a stop member that limits the upward movement of the gear 71. Therefore, in the gear mechanism 70A, the guide metal 80 of the reciprocating mechanism 70B can be used to limit the upward movement of the gear 71. That is, in the gear mechanism 70A, the upward movement of the gear 71 can be limited without providing a separate member that limits the upward movement of the gear 71 (to one side in the thrust direction). Therefore, an increase in the number of parts of the drive mechanism 70 (gear mechanism portion 70A) can be suppressed, and the cost of the electric cutter 10 can be reduced.

[0071] Furthermore, the lower surface 80B of the guide metal 80 is configured as a receiving surface that receives (supports) the gear 71, and is installed on the installation portion 42F of the case body 42. This allows the guide metal 80 to be installed in the inner case 40 based on the lower surface 80B of the guide metal 80 that receives the gear 71. Therefore, the gear 71 and the guide metal 80 can be housed in the inner case 40 while suppressing displacement of the gear 71 and the guide metal 80 relative to each other in the vertical direction.

[0072] As described above, the lower surface 80B of the guide metal 80 is configured as a receiving surface that receives (supports) the gear 71, and the connector 83 of the plunger 82 is inserted into a slit 80A formed in the middle of the guide metal 80 in the vertical direction. This allows the gear 71 to be disposed adjacent to the lower side of the guide metal 80, while the plunger 82 (connector) can be disposed in the middle of the guide metal 80 in the vertical direction. This can contribute to downsizing of the drive mechanism 70 in the vertical direction.

[0073] Furthermore, the guide metal 80 is disposed above the outer periphery of the gear 71. As a result, when the gear 71 moving upward is received by the lower surface 80B of the guide metal 80, the outer periphery of the gear 71 abuts against the lower surface 80B of the guide metal 80 and slides on the lower surface 80B of the guide metal 80. As a result, the sliding resistance of the gear 71 when it rotates can be reduced compared to when the entire gear 71 abuts against the lower surface 80B of the guide metal 80.

[0074] Furthermore, a pair of guide metals 80 are arranged spaced apart in the left-right direction within the case body 42. This allows the pair of guide metals 80 to movably support both left-right sides of the connector 83 of the plunger 82 and to receive both left-right sides of the gear 71 moving upward. This improves the support performance of the guide metal 80 for the connector 83, and allows the gear 71 moving upward to be received in a balanced manner by the guide metal 80.

[0075] Furthermore, the crank pin 75 of the gear 71 is disposed between a pair of left and right guide metals 80. As a result, even when the gear 71 and the guide metals 80 are disposed adjacent to each other in the vertical direction, the crank pin 75 can be disposed between the pair of left and right guide metals 80, and the rotational force of the gear 71 can be transmitted to the connector 83 (plunger 82).

[0076] Furthermore, the ring member 104 in the vibration reduction mechanism 70C is disposed adjacent to the upper side of the guide metal 80, and the guide metal 80 supports the ring member 104 from below. This makes it possible to limit downward movement of the ring member 104 by utilizing the guide metal 80, which movably supports the plunger 82. Therefore, it is not necessary to provide a separate member in the vibration reduction mechanism 70C to limit downward movement of the ring member 104. This further suppresses an increase in the number of parts in the drive mechanism 70, thereby achieving cost reduction for the electric cutter 10. Furthermore, it is possible to effectively reduce the size of the drive mechanism 70 in the vertical direction.

[0077] Furthermore, the ring member 104 is connected to the gear 71 by the crank pin 75 of the gear 71. That is, the gear 71 can be connected to the plunger 82 and the ring member 104 by the crank pin 75 disposed between the pair of left and right guide metals 80. Therefore, an efficient arrangement structure can be realized in the drive mechanism 70, and this can contribute to making the drive mechanism 70 more compact.

[0078] Furthermore, the guide metal 80 is made of a single component, which contributes to reducing the cost of the guide metal 80 alone.

[0079] Furthermore, the guide metal 80 is made of a sintered material and is impregnated with a lubricant. This allows the gear 71, connector 83, and ring member 104 to be supported by the guide metal 80, thereby reducing sliding resistance when the gear 71, connector 83, and ring member 104 slide on the guide metal 80. This, for example, can improve the durability of the drive mechanism 70.

[0080] Furthermore, in the electric cutting machine 10, the inner case 40 includes a box-shaped case body 42 that is open upward and a case cover 44 that closes the opening 42M of the case body 42. The drive mechanism 70 is housed within the inner case 40 and is positioned so as not to protrude upward from the opening 42M of the case body 42. Therefore, the case cover 44 can be formed into a flat plate with its thickness extending vertically, thereby closing the opening 42M of the case cover 44. This allows the case cover 44 to be formed by pressing (punching) a metal plate. Therefore, the costs of the case cover 44 and the inner case 40 can be reduced compared to, for example, when the case cover 44 is made by casting.

[0081] The case cover 44 is fastened to the case body 42 by fixing bolts BL1 and BL2, and the case body 42 is provided with a fixing sleeve 48 that is fastened to the case body 42 together with the case cover 44. The lower part of the fixing sleeve 48 is fitted into a positioning recess 100A of a base member 100 in the vibration reduction mechanism 70C, and the position of the base member 100 is determined by the fixing sleeve 48. The stepped portion 48A of the fixing sleeve 48 is disposed adjacent to the upper side of the edge of the positioning recess 100A, and the base member 100 is fixed to the case body 42. As a result, the base member 100 can be fixed to the case body 42 while being positioned using the fixing bolt BL1 and the fixing sleeve 48 that are used to fix the case cover 44 to the case body 42.

[0082] The base member 100 also constitutes a part of the vibration reduction mechanism 70C, and is disposed adjacent to the upper side of the guide metal 80 of the reciprocating mechanism 70B. This allows the base member 100 to restrict upward movement of the reciprocating mechanism 70B and the gear mechanism 70A. Therefore, the base member 100, which is fastened to the case body 42 together with the case cover 44 and the fixed sleeve 48, functions as a stopper member for the gear mechanism 70A and the reciprocating mechanism 70B, and can maintain a good accommodation state of the gear mechanism 70A and the reciprocating mechanism 70B in the case body 42.

[0083] Furthermore, gear 71 is rotatably provided on the bottom of case body 42 with its axis extending vertically. Furthermore, shaft accommodating section 42C, which connects the inside and outside of case body 42, is provided on the bottom of case body 42, and drive shaft 61 of motor 60 is accommodated in shaft accommodating section 42C. This allows power of motor 60 to be transmitted to gear 71 while motor 60 is disposed outside case body 42.

[0084] A motor holding portion 42K extending downward is formed at the rear end of the case body 42, and the motor 60 is held by the motor holding portion 42K. Specifically, a motor bearing 66 that rotatably supports the lower end of the drive shaft 61 of the motor 60 is held by a bearing holder 67, and the bearing holder 67 is fitted into the motor holding portion 42K from below and held by the motor holding portion 42K. This allows the motor 60 to be unitized with the inner case 40 that houses the drive mechanism 70, and the unitized inner case 40 and motor 60 can be assembled to the housing 20. This improves the ease of assembly of the electric cutter 10.

[0085] Furthermore, in the reciprocating mechanism 70B, the guide metal 80 is sandwiched in the vertical direction between the base member 100 and the installation portion F of the protruding portion 42D of the case main body 42, thereby restricting the movement of the guide metal 80 in the vertical direction. As described above, the guide metal 80 receives the gear 71 moving upward, restricting the upward movement of the gear 71. This allows the guide metal 80, which restricts the upward movement of the gear 71, to be fixed to the case main body 42 by the base member 100. That is, the fixing bolt BL1 and the fixing sleeve 48 fix the case cover 44, the base member 100, and the guide metal 80 to the case main body 42, while restricting the upward movement of the gear 71.

[0086] Furthermore, an insertion portion 42J through which the output shaft 84 of the plunger 82 is inserted is formed at the front end of the case body 42. This allows the front end of the output shaft 84 to be disposed outside the inner case 40, and the blade attachment mechanism 92 to be disposed outside the inner case 40.

[0087] Furthermore, in the vibration reduction mechanism 70C, the counterweight 108 is supported in a rolling manner by the first rolling balls 110 and the second rolling balls 114. The second rolling balls 114 are disposed between the counterweight 108 and the case cover 44 and abut against both of them. This makes it possible to support the counterweight 108 by utilizing the case cover 44 that closes the opening 42M of the case main body 42. This contributes to a reduction in the number of parts of the vibration reduction mechanism 70C and effectively reduces the cost of the drive mechanism 70.

[0088] The inner case 40 also accommodates the vibration reduction mechanism 70C (counterweight 108) above the reciprocating mechanism 70B (plunger 82). The inner case 40 is attached to the housing 20 so that the reciprocating mechanism 70B (plunger 82) is positioned above the vertical center 20B1 of the handle housing 20B in the housing 20. Specifically, the vertical center 20B1 of the handle housing 20B is positioned below the axis CL of the output shaft 84 of the reciprocating mechanism 70B. Therefore, during cutting, the operator holds the handle housing 20B, which is positioned below the plunger 82, and the vibration reduction mechanism 70C, which is positioned above the plunger 82, reduces vibrations generated by the plunger 82. As a result, during cutting, the front end of the blade 95 acts to trace an elliptical path when viewed from the left and right. This improves the cutting performance of the electric cutter 10 on the workpiece. [Explanation of symbols]

[0089] 10 Electric cutting machine (work machine) 20. Housing 20B Handle housing (handle) 20B1 Center of the handle 40 Inner case (case) 42 Case body 42C Shaft housing section (communication section) 42J Insertion part 42K Motor holder (holder) 42M opening 44 Case Cover (Cover) 48 Fixing sleeve (fixing device) BL1 Fixing bolt (fastening member) BL2 Fixing bolt (fastening member) 60 Motor (drive source) 70 Drive mechanism 70A Gear mechanism (first drive mechanism) 70B reciprocating mechanism (second drive mechanism) 70C Vibration reduction mechanism (third drive mechanism) 71 Gear (first driving member) 80 Guide metal (receiving member) 82 plunger (second driving member) 95 Blade (cutting tool) 100 Base member 102 Guide member 108 Counterweight 110 First Rolling Ball (First Ball) 114 Second Rolling Ball (Second Ball)

Claims

1. A driving source; an output section extending in the front-rear direction, holding the tool bit and driven by the drive source; a drive mechanism connected to the drive source and configured to operate the output unit; a case that houses the drive mechanism; Equipped with The case is a box-shaped case body having an opening that opens upward to accommodate the drive mechanism therein, and an insertion portion that opens forward and through which a part of the output portion is inserted; a cover that is a metal plate-shaped member formed by press working and that closes the opening; It is composed of The drive mechanism is disposed within a space defined by the case body and the cover, and is disposed so as not to protrude above the opening.

2. A work machine as described in claim 1, wherein the case body is formed by metal casting.

3. The drive mechanism has a guide portion that operably supports the output portion, The work machine according to claim 1 , wherein the cover restricts upward movement of the guide portion.

4. The output section is reciprocated along the front-to-rear direction by the drive source, The work machine according to claim 3 , wherein the guide portion slidably supports the output portion.

5. The cover includes a fastening member that covers a hole provided in the cover, The work machine according to any one of claims 1 to 4, wherein the fastening member connected to the case body prevents the cover from moving away from the case body.

6. The drive source reciprocates the tool bit in a forward and backward direction using the drive mechanism, a vibration reduction mechanism that reduces forward and backward vibrations that occur when the tool bit is operated by the drive mechanism, the vibration reduction mechanism includes a counterweight that reciprocates in a front-to-rear direction by the drive source, and a weight support portion that is housed in the case main body and supports the counterweight so that the counterweight can reciprocate, The work machine according to claim 1 , wherein the cover restricts upward movement of at least one of the counterweight and the weight support portion.

7. A rolling body that reciprocates in the forward and backward directions due to the operation of the counterweight is disposed between the cover and the counterweight, The work machine according to claim 6, wherein the counterweight is supported by the cover via the rolling elements, thereby restricting upward movement of the counterweight.

8. The case body has a communication part that is open on the lower side, The work machine according to claim 1 , wherein the communication portion is closed by the drive source.

9. A drive source; at least one reciprocating body extending along the front-rear direction and reciprocated in the front-rear direction by the drive source; At least one support portion that supports the reciprocating body so that the reciprocating body can move back and forth; a transmission mechanism that transmits the power of the drive source to the reciprocating body; a case that houses the transmission mechanism; Equipped with the reciprocating body includes an output section that holds a tool bit and is reciprocally driven by the drive source, The case is a box-shaped case body having an opening that opens upward to accommodate the transmission mechanism therein, and an insertion portion that opens forward and through which a portion of the output portion is inserted; a cover that is a metal plate-shaped member formed by press working and that closes the opening; It is composed of the transmission mechanism is disposed within a space defined by the case body and the cover, and is disposed so as not to protrude above the opening, The work machine, wherein at least one of the at least one reciprocating body and the at least one support portion is restricted from moving upward by the cover.

10. A gear that rotates around an axis in the vertical direction and transmits the power of the drive source to the reciprocating body, The work machine according to claim 9 , wherein the cover restricts upward movement of the gear.

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