Chainsaw

Abstract

The present invention provides a chainsaw. The chainsaw applies a technique capable of suppressing the nut from becoming high temperature. The chainsaw includes: a saw chain; a guide bar on which the saw chain is mounted; a sprocket that causes the saw chain to travel along the periphery of the guide bar; a prime mover that rotates the sprocket; a fuel tank that stores oil supplied to the saw chain; a housing that houses the prime mover and the fuel tank; a bolt that protrudes from the housing and passes through a hole provided in the guide bar; a nut that is threadedly engaged with the bolt to fix the guide bar to the housing; and a heat dissipation structure that dissipates heat from the bolt into the oil in the fuel tank.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a chainsaw. Background Art

[0002] In Patent Document 1, a chainsaw is disclosed. The chainsaw includes: a saw chain; a guide bar on which the saw chain is mounted; a sprocket that causes the saw chain to travel along the circumference of the guide bar; a prime mover that rotates the sprocket; a fuel tank that stores oil supplied to the saw chain; a housing that houses the prime mover and the fuel tank; a bolt that protrudes from the housing and passes through a hole provided in the guide bar; and a nut that is threadedly engaged with the bolt to fix the guide bar to the housing.

[0003] Prior Art Documents

[0004] Patent Document

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-279884 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] When using a chainsaw to cut a workpiece, the guide bar becomes hot due to the frictional heat between the traveling saw chain and the guide bar. In the above structure, the heat of the guide bar is transferred to the nut, and the nut becomes hot. There is a possibility that an operator may touch the hot nut. In this specification, a technology capable of suppressing the nut from becoming hot is provided.

[0008] Solution to the Problem

[0009] This specification discloses a chainsaw. The chainsaw includes: a saw chain; a guide bar on which the saw chain is mounted; a sprocket that causes the saw chain to travel along the circumference of the guide bar; a prime mover that rotates the sprocket; a fuel tank that stores oil supplied to the saw chain; a housing that houses the prime mover and the fuel tank; a bolt that protrudes from the housing and passes through a hole provided in the guide bar; a nut that is threadedly engaged with the bolt to fix the guide bar to the housing; and a heat dissipation structure that dissipates heat from the bolt into the oil in the fuel tank.

[0010] In the above structure, the heat of the nut is transferred to the bolt, and the heat dissipation structure dissipates the heat of the bolt into the oil in the fuel tank, so that the bolt can be prevented from becoming hot. Accordingly, the nut can be prevented from becoming hot. Brief Description of the Drawings

[0011] Figure 1 It is a perspective view of the chainsaw 2 according to the first embodiment as viewed from the rear left side.

[0012] Figure 2 It is a perspective view of the chainsaw 2 according to the first embodiment as viewed from the front right side.

[0013] Figure 3The right view of the state where the sprocket cover 20 of the chainsaw 2 of the first embodiment is removed.

[0014] Figure 4 The right view of the chainsaw 2 of the first embodiment.

[0015] Figure 5 The left view of the state where the side handle 14 and the left housing 10 of the chainsaw 2 of the first embodiment are removed.

[0016] Figure 6 The horizontal cross-sectional view of the chainsaw 2 of the first embodiment.

[0017] Figure 7 The right view of the state where the sprocket cover 20, the guide bar 6, and the brake cover 18 of the chainsaw 2 of the first embodiment are removed.

[0018] Figure 8 The longitudinal cross-sectional view of the chainsaw 2 of the first embodiment.

[0019] Figure 9 The longitudinal cross-sectional view of the chainsaw 2 of the second embodiment.

[0020] Figure 10 The horizontal cross-sectional view of the chainsaw 2 of the second embodiment.

[0021] Figure 11 The longitudinal cross-sectional view of the chainsaw 2 of the third embodiment.

[0022] Figure 12 The horizontal cross-sectional view of the chainsaw 2 of the third embodiment.

[0023] Explanation of reference numerals

[0024] 2: Chainsaw; 4: Main body; 6: Guide bar; 6a: Long hole; 7a: Mounting portion; 7b: Cutting portion; 8: Saw chain; 22: Main body housing; 48: Motor; 50: Fuel tank; 52: Oil pump; 70: Sprocket; 82: Bolt; 84: Nut; 84a: Internal thread portion; 100: Supplementary opening; 102: Cover; 118: Washer; 120: Outer portion; 120a: External thread portion; 122: Fixed portion; 124: Inner portion; 126: Fixed hole; 128: Recess; 130, 230: Heat dissipation structure; 132, 232: Heat dissipation member; 132: Heat sink; 134, 234: Base portion; 136: Upper fin; 138: Lower fin; 140, 240: Fixed hole; 142, 242: Fixed bolt; 232: Flexible member; 236: Chain portion; B: Battery pack. Detailed description of the embodiments

[0025] Hereinafter, representative and non-limiting specific examples of the present invention will be described in detail with reference to the accompanying drawings. This detailed description is only intended to show those skilled in the art the details of the preferred examples for implementing the present invention, and is not intended to limit the scope of the present invention. In addition, the disclosed additional features and technical solutions can be used independently of other features and technical solutions or in combination with other features and technical solutions to provide a further improved chainsaw.

[0026] In addition, the combination of features and processes disclosed in the following detailed description is not essential in the broadest sense when implementing the present invention, and is only described to specifically illustrate representative specific examples of the present invention. Furthermore, when providing additional and useful embodiments of the present invention, the various features of the following representative specific examples and the various features recited in the claims do not have to be combined in the specific examples and in the order recited herein.

[0027] All features recited in this specification and / or claims are intended to be defined separately from the structures of the features recited in the embodiments and / or claims as limitations on the specific matters recited in the disclosure of the original application and the claims, and are disclosed separately and independently of each other. Furthermore, all numerical ranges and descriptions related to organizations or groups are intended to disclose their intermediate structures as limitations on the specific matters recited in the disclosure of the original application and the claims.

[0028] In one or more embodiments, the heat dissipation structure may include a heat dissipation member that contacts the bolt, and at least a part of the heat dissipation member is disposed inside the fuel tank.

[0029] In the above structure, by bringing at least a part of the heat dissipation member into contact with the oil in the fuel tank, the heat of the heat dissipation member is dissipated into the oil. Therefore, it is possible to prevent the nut from becoming hot.

[0030] In one or more embodiments, the heat dissipation member may include a metal heat sink.

[0031] In the above structure, compared with the case where the heat dissipation member does not include heat sinks, the area of contact between the heat dissipation member and the oil in the fuel tank can be increased. Therefore, the heat of the heat dissipation member is easily dissipated into the oil. Therefore, it is possible to further prevent the nut from becoming hot.

[0032] In one or more embodiments, the heat dissipation member may include a metal flexible member that hangs down along the direction of gravity regardless of the posture of the chainsaw.

[0033] In the above structure, regardless of the posture of the chain saw, the flexible member can contact the oil in the fuel tank. Therefore, the heat of the heat dissipation member is easily dissipated into the oil. As a result, it is possible to further suppress the nut from becoming high temperature.

[0034] In one or more embodiments, it may also be that when an amount of oil equal to a first ratio of the capacity of the fuel tank is stored in the fuel tank and the chain saw is placed on the ground, the liquid level of the oil is located above at least a part of the lower end of the heat dissipation member.

[0035] In the above structure, if an amount of oil equal to a first ratio of the capacity of the fuel tank is stored in the fuel tank, when the chain saw is in the same posture as when placed on the ground, the heat dissipation member can contact the oil in the fuel tank, so that the heat of the heat dissipation member is easily dissipated into the oil. As a result, it is possible to further suppress the nut from becoming high temperature.

[0036] In one or more embodiments, it may also be that the first ratio is 50% or less of the capacity of the fuel tank.

[0037] During the operation of the chain saw, in order to prevent the oil in the fuel tank from running out, usually, a sufficient amount of oil is stored in the fuel tank. However, when the chain saw is used continuously for a long time, the amount of oil in the fuel tank sometimes decreases to an amount equal to or less than 50% of the capacity of the fuel tank. In the above structure, even when the chain saw is used continuously for a long time and the chain saw is in the same posture as when placed on the ground, the heat dissipation member can contact the oil in the fuel tank, and the heat of the heat dissipation member is easily dissipated into the oil. As a result, it is possible to further suppress the nut from becoming high temperature.

[0038] In one or more embodiments, it may also be that at least a part of the heat dissipation member includes a part disposed inside the fuel tank at a position more than 10% of the length of the fuel tank away from the inner surface of the fuel tank in the extending direction of the bolt.

[0039] In the above structure, by disposing at least a part of the heat dissipation member at a deeper position inside the fuel tank, the contact area between the heat dissipation member and the oil in the fuel tank can be increased, so that the heat of the heat dissipation member is easily dissipated into the oil. As a result, it is possible to further suppress the nut from becoming high temperature.

[0040] In one or more embodiments, the bolt may also penetrate the fuel tank from the outside to the inside. The part of the bolt inside the fuel tank may also constitute a heat dissipation structure. The part of the bolt inside the fuel tank may also include a part disposed inside the fuel tank at a position more than 10% of the length of the fuel tank away from the inner surface of the fuel tank in the extending direction of the bolt.

[0041] In the above structure, by disposing the bolt at a deeper position inside the fuel tank, the contact area between the bolt and the oil inside the fuel tank can be increased, so that the heat of the bolt can be easily dissipated into the oil. Thereby, the nut can be further prevented from becoming high temperature.

[0042] In one or more embodiments, it may also be that when an amount of oil equal to the first ratio of the capacity of the fuel tank is stored in the fuel tank and the chainsaw is placed on the ground, the liquid level of the oil is located at a position above the lower end of the inner part of the fuel tank of the bolt.

[0043] In the above structure, if an amount of oil equal to the first ratio of the capacity of the fuel tank is stored in the fuel tank, when the chainsaw is in the same posture as when placed on the ground, the bolt can contact the oil inside the fuel tank, so that the heat of the bolt can be easily dissipated into the oil. Therefore, the nut can be further prevented from becoming high temperature.

[0044] In one or more embodiments, the first ratio may be 50% or less of the capacity of the fuel tank.

[0045] In the above structure, even when the chainsaw is used continuously for a long time and the amount of oil in the fuel tank is reduced to 50% or less of the capacity of the fuel tank, when the chainsaw is in the same posture as when placed on the ground, the bolt can contact the oil, and the heat of the bolt can be easily dissipated into the oil. Thereby, the nut can be further prevented from becoming high temperature.

[0046] In one or more embodiments, the guide bar may also include a cutting portion located at a position closer to the tip of the guide bar than the housing in the length direction of the guide bar. The length of the cutting portion may also be 250 mm or less in the length direction.

[0047] Generally, as the length of the cutting portion becomes shorter, the curvature of the periphery of the guide bar becomes larger. Therefore, the frictional heat between the saw chain and the guide bar becomes larger, and the guide bar is likely to become a higher temperature. In the above structure, the heat transferred from the guide bar that has become a higher temperature to the bolt can be dissipated into the oil inside the fuel tank through the heat dissipation structure. Thereby, the nut can be prevented from becoming high temperature.

[0048] In one or more embodiments, the prime mover may also be a motor.

[0049] In the above structure, compared with the case where the prime mover is an engine, it is not easy to have a high-temperature part on the housing. Therefore, it is more likely that the operator inadvertently touches the nut. In the above structure, since the heat dissipation structure dissipates the heat of the bolt into the oil inside the fuel tank, the nut can be prevented from becoming high temperature.

[0050] In one or more embodiments, the chainsaw may further include a battery pack that can be detached from and attached to the housing. The motor can also be driven using power from the battery pack.

[0051] In the above structure, since no power cord is required, the operability of the chainsaw is better, but there is a greater possibility that the operator may accidentally touch the nut. In the above structure, since the heat dissipation structure dissipates the heat of the bolt into the oil in the fuel tank, the nut can be prevented from becoming high temperature.

[0052] (First Embodiment)

[0053] Refer to Figures 1 - 8 The chainsaw 2 of the first embodiment will be described. The chainsaw 2 includes a main body 4, a guide bar 6, and a saw chain 8. The guide bar 6 has an elongated plate shape. The guide bar 6 is attached to the main body 4 so as to protrude forward from the main body 4. The saw chain 8 includes a plurality of cutters connected to each other. The saw chain 8 is installed along the periphery of the guide bar 6. A battery pack B is installed on the main body 4. The chainsaw 2 drives the saw chain 8 using the power supplied from the battery pack B to rotate it along the periphery of the guide bar 6 to cut an object to be cut such as wood. In the following description, as Figure 3 shown, when the chainsaw 2 is placed on a placement surface P such as the ground, the direction orthogonal to the placement surface P is called the vertical direction, the direction obtained by projecting the length direction of the guide bar 6 onto the placement surface P is called the front-rear direction, and the direction orthogonal to the vertical direction and the front-rear direction is called the left-right direction. In addition, in the drawings other than Figure 1 、 Figure 2 、 Figure 4 、 for the sake of clarity of the drawing, the illustration of the saw chain 8 is omitted.

[0054] As Figure 1 and Figure 2 shown, the main body 4 includes a left housing 10, a right housing 12, a side handle 14, a guard 16, a brake cover 18, and a sprocket cover 20. The main body housing 22 and the upper handle 24 are formed by the left housing 10 and the right housing 12. The left housing 10 defines the outer shape of the left half of the main body housing 22 and the upper handle 24, and the right housing 12 defines the outer shape of the right half of the main body housing 22 and the upper handle 24.

[0055] As Figure 3As shown, the guide rod 6 is installed on the right housing 12. The guide rod 6 includes a mounting portion 7a facing the right housing 12 and a cutting portion 7b protruding forward from the right housing 12. In the longitudinal direction of the guide rod 6, the length Lg of the cutting portion 7b is 200 mm. Here, the length Lg refers to the length from the boundary between the mounting portion 7a and the cutting portion 7b to the tip of the cutting portion 7b. In addition, in the longitudinal direction of the guide rod 6, the position of the boundary between the mounting portion 7a and the cutting portion 7b coincides with the position of the tip of the right housing 12. Furthermore, in a modified example, in the longitudinal direction of the guide rod 6, the length Lg of the cutting portion 7b may also be any value of 250 mm or less.

[0056] As Figure 4 shown, the main body housing 22 includes a front main body housing 28 having a substantially rectangular parallelepiped shape with a longitudinal direction in the front-rear direction of the main body 4 and a rear main body housing 30 extending rearward from the upper part of the rear surface of the front main body housing 28. A battery pack B is detachably mounted on the lower surface of the rear main body housing 30. When the chainsaw 2 is placed on the placement surface P with the battery pack B mounted thereon, the lower surface of the front main body housing 28 abuts against the placement surface P, and the lower surface of the battery pack B also abuts against the placement surface P.

[0057] As Figure 1 shown, the upper handle 24 includes a support portion 32 having a substantially prismatic shape and a grip portion 34 having a substantially cylindrical shape. The support portion 32 extends upward from the front upper surface of the front main body housing 28. A recess 36 is formed on the upper surface of the support portion 32. Inside the recess 36, a power switch 38 for an operator to switch on and off the power of the chainsaw 2 and a power lamp 40 for displaying the on and off state of the power of the chainsaw 2 are arranged. The grip portion 34 extends rearward from the upper part of the rear surface of the support portion 32 and bends downward to connect to the upper surface of the rear main body housing 30. A trigger switch 42 for an operator to operate the rotational drive of the saw chain 8 is arranged at the front lower surface of the grip portion 34. A trigger lock lever 44 is arranged at the upper part of the grip portion 34, and the trigger lock lever 44 switches between a state allowing an operator to operate the trigger switch 42 and a state prohibiting the operation.

[0058] The side handle 14 has a substantially U-shaped outer shape that connects the upper left surface of the support portion 32 of the upper handle 24 and the rear left surface of the front main body housing 28. The cross-sectional shape of the side handle 14 is a substantially circular shape. When the operator uses the chainsaw 2, the operator holds the upper handle 24 with the right hand and the side handle 14 with the left hand to hold the chainsaw 2. When the operator presses the trigger lock lever 44 of the upper handle 24 with the palm of the right hand from this state, it becomes a state where the operator is allowed to operate the trigger switch 42. The operator drives the saw chain 8 to rotate by pushing up the trigger switch 42 with the index finger of the right hand in this state.

[0059] As Figure 5 shown, the chainsaw 2 includes a motor 48, a fuel tank 50, an oil pump 52, and a control unit 54. The motor 48, the fuel tank 50, and the oil pump 52 are arranged inside the front main body housing 28. The control unit 54 is arranged inside the rear main body housing 30.

[0060] As Figure 6 shown, the motor 48 is an outer rotor type DC brushless motor. The motor 48 includes a stator 58 wound with a winding 56, a rotor 60 arranged outside the stator 58, a cooling fan 62 fitted to the rotor 60, and a shaft 64 arranged to penetrate the centers of the stator 58 and the rotor 60 and fitted to the cooling fan 62. The stator 58 is fixed to the main body housing 22. The winding 56 is electrically connected to the control unit 54 (refer to Figure 5 ). The shaft 64 is arranged along the left-right direction of the chainsaw 2 and is rotatably supported by the main body housing 22 by means of bearings 66, 68. The bearing 66 is arranged at a position to the right of the stator 58, and the bearing 68 is arranged at a position to the left of the stator 58 and the cooling fan 62. A sprocket 70 and a brake base 72 are fixed near the right end of the shaft 64. The sprocket 70 and the brake base 72 are arranged at a position to the right of the bearing 66. A brake drum 74 is fitted to the brake base 72.

[0061] As Figure 3 shown, the sprocket 70 is exposed outside the right housing 12. The saw chain 8 is stretched from the guide bar 6 to the sprocket 70 (refer to Figure 1 , Figure 2 and Figure 4 ). When the motor 48 is driven, the sprocket 70 rotates together with the shaft 64. Thereby, the saw chain 8 rotates around the sprocket 70 and the guide bar 6.

[0062] The guide bar 6 is fixed to the right housing 12 in a state of being clamped by the inner guide plate 76 and the outer guide plate 78. The inner guide plate 76 has a shape that bends toward the left near the upper end and near the lower end. The outer guide plate 78 has a shape that bends toward the right near the upper end and near the lower end. A long hole 6a extending in the length direction of the guide bar 6 is formed in the mounting portion 7a of the guide bar 6. The guide bar 6 is supported on the main body housing 22 by a support pin 80 and a bolt 82 passing through the long hole 6a. As Figure 2 and Figure 4 shown, a nut 84 tightened from the outside of the sprocket cover 20 and the outer guide plate 78 is installed on the bolt 82. An operator can change the distance between the guide bar 6 and the sprocket 70 by sliding the guide bar 6 along the long hole 6a in a state where the nut 84 is loosened, thereby adjusting the tension of the saw chain 8.

[0063] As Figure 3 shown, an engaging hole 88 that engages with an engaging claw 86 is formed in the guide bar 6. As Figure 7 shown, the engaging claw 86 is connected to an adjusting screw 92 by a rotary-linear motion conversion mechanism 90. The rotary-linear motion conversion mechanism 90 converts the rotational motion of the adjusting screw 92 into a linear motion of the engaging claw 86 along the direction of the long hole 6a. As Figure 6 shown, the adjusting screw 92 passes through the long hole 6a in a manner that does not contact the inner peripheral surface of the long hole 6a. When an operator rotates the adjusting screw 92, the engaging claw 86 moves in the direction of the long hole 6a of the guide bar 6, and the guide bar 6 slides in the direction of the long hole 6a.

[0064] As Figure 2 and Figure 4 shown, the sprocket 70, the inner guide plate 76, the outer guide plate 78, and the support pin 80 are covered by the sprocket cover 20. An outer cover 94 is installed on the sprocket cover 20. A fastening opening 94a for accessing the nut 84 fastened to the bolt 82 from the outside and an adjusting opening 94b for accessing the adjusting screw 92 from the outside are formed in the outer cover 94. An operator can tighten or loosen the nut 84 in a state where the sprocket cover 20 is installed. In addition, an operator can rotate the adjusting screw 92 in a state where the sprocket cover 20 is installed to adjust the tension of the saw chain 8.

[0065] As Figure 7 shown, the guard 16 is connected to the brake shoe 98 by a link mechanism 96. The guard 16 can swing about a swing axis extending in the left-right direction. The brake shoe 98 is arranged so as to surround the periphery of the brake drum 74. When the guard 16 falls forward, the link mechanism 96 causes the brake shoe 98 to reduce its diameter, and when the guard 16 returns to the rear side, the link mechanism 96 causes the brake shoe 98 to increase its diameter. When the brake shoe 98 reduces its diameter, the inner peripheral surface of the brake shoe 98 abuts against the outer peripheral surface of the brake drum 74, and the rotation of the shaft 64 is braked by the frictional force therebetween.

[0066] Figure 5 The fuel tank 50 shown stores oil for lubricating the saw chain 8. The fuel tank 50 is arranged at a position forward of the motor 48 and the oil pump 52. As Figure 6 shown, the fuel tank 50 has a longitudinal direction in the left-right direction. The fuel tank 50 is made of a resin material. The right end portion of the fuel tank 50 is welded to the inner surface of the right housing 12. Thereby, a space for storing oil is defined between the inner surface of the fuel tank 50 and the inner surface of the right housing 12. The right housing 12 forms a part of the fuel tank 50. Hereinafter, sometimes, the portion of the right housing 12 that defines the space inside the fuel tank 50 will be described as a part of the fuel tank 50. In addition, since the right end portion of the fuel tank 50 is closed by the inner surface of the right housing 12, oil does not leak to the outside of the fuel tank 50. Further, in a modified example, the fuel tank 50 may be integrally formed with the right housing 12. On the left side surface of the fuel tank 50, a replenishment opening 100 for replenishing oil to the fuel tank 50 is formed. A detachable cover 102 is provided at the replenishment opening 100. As Figure 1 shown, the cover 102 of the fuel tank 50 is exposed outside the left housing 10 and is arranged at the lower part of the left surface of the front main body housing 28. In addition, a confirmation opening 104 for visually recognizing the liquid level of the fuel tank 50 from the outside is formed at a position of the left housing 10 forward of the cover 102.

[0067] Figure 5 The oil pump 52 shown is linked to the rotation of the motor 48 and sucks the oil inside the fuel tank 50 via the inlet pipe 106, and sends the oil toward the guide bar 6 via the outlet pipe 108. As Figure 8 shown, at the tip of the inlet pipe 106, an inlet opening (not shown) for sucking the oil inside the fuel tank 50 is provided, and the inlet opening is arranged near the lower surface of the fuel tank 50 inside the fuel tank 50. As Figure 5 shown, the worm wheel 110 for driving the oil pump 52 is fitted near the left end of the shaft 64 of the motor 48. As Figure 6 shown, the worm wheel 110 is arranged at a position to the left of the stator 58 and the cooling fan 62 and to the right of the bearing 68. The displacement of the oil supplied from the fuel tank 50 to the guide bar 6 by the oil pump 52 can be adjusted by means of an adjustment pin 112 (refer to Figure 5 ).

[0068] As Figure 1 shown, an adjustment opening 114 for accessing the adjustment pin 112 from the outside is formed on the upper surface of the main body housing 22. An operator can adjust the displacement of the oil of the oil pump 52 by inserting a tool through the adjustment opening 114 and rotating the adjustment pin 112.

[0069] Next, a detailed description will be given of Figure 6The bolt 82 shown. The bolt 82 is made of a metallic material. The metallic material is, for example, iron. The bolt 82 is fixed to the right housing 12 by insert molding. The bolt 82 has a cylindrical shape extending in the left - right direction. The bolt 82 includes an outer portion 120, a fixing portion 122, and an inner portion 124. The outer portion 120 protrudes toward the right from the right surface of the right housing 12. The outer portion 120 passes through the long hole 6a provided in the guide rod 6. An external thread portion 120a is formed on the outer peripheral surface near the right end portion of the outer portion 120. By screwing the internal thread portion 84a formed on the inner peripheral surface of the nut 84 with the external thread portion 120a, the nut 84 is mounted on the outer portion 120. When the nut 84 is mounted on the outer portion 120, the sprocket cover 20, the outer guide plate 78, the guide rod 6, the inner guide plate 76, and the washer 118 are sandwiched and fixed between the nut 84 and the right housing 12.

[0070] The fixing portion 122 is disposed on the left side of the outer portion 120. The fixing portion 122 penetrates the right housing 12 from the right surface to the inner surface (that is, penetrates the fuel tank 50 from the outside to the inside). The fixing portion 122 is in contact with the right housing 12 without a gap. The fixing portion 122 has a recess 128 that is recessed from the outer peripheral surface toward the radial inner side of the fixing portion 122 near the center in the left - right direction. When the right housing 12 is integrally formed with the bolt 82 by insert molding, the resin material enters the recess 128. Therefore, the fixing portion 122 is fitted with the right housing 12 and is firmly fixed. When an operator fixes the guide rod 6 to the right housing 12, even when an excessive force is applied to the nut 84 using a jig such as a wrench, the bolt 82 can be prevented from coming off the right housing 12.

[0071] The inner portion 124 is disposed on the left side of the fixing portion 122. The inner portion 124 is disposed inside the fuel tank 50. The inner portion 124 extends in the left - right direction to a position that is at a first distance L1 away from the inner surface of the fuel tank 50. In the present embodiment, the first distance L1 is 5% or more and 10% or less of the length Lo in the left - right direction of the fuel tank 50. Here, the length Lo in the left - right direction of the fuel tank 50 is the length from the welding portion of the right end portion of the fuel tank 50 and the right housing 12 to the left end portion of the fuel tank 50. The inner portion 124 is disposed near the center of the fuel tank 50 in the front - rear direction. As Figure 8 shown, the inner portion 124 is spaced from the lower surface of the fuel tank 50 on the upper side and is disposed at a position above the top end portion of the inlet pipe 106. The upper end portion of the inner portion 124 is disposed above the upper end portion of the replenishment opening 100 of the fuel tank 50, and the lower end portion of the inner portion 124 is disposed below the upper end portion of the replenishment opening 100 and above the lower end portion of the replenishment opening 100. In addition, a fixing hole 126 that is recessed toward the right is formed on the left end surface of the inner portion 124.

[0072] The chain saw 2 further includes a heat dissipation structure 130. The heat dissipation structure 130 includes a heat dissipation member 132 and a fixing bolt 142. In the present embodiment, the heat dissipation member 132 is composed of heat dissipation fins. Hereinafter, the same reference numerals as those of the heat dissipation member 132 will be given to the heat dissipation fins and they will be described. The heat dissipation fin 132 is made of a metal material. As the metal material, for example, a material with high heat transfer performance such as aluminum is used. The heat dissipation fin 132 is disposed inside the fuel tank 50. The heat dissipation fin 132 includes a base portion 134, a plurality of (three in the present embodiment) upper fins 136, and a plurality of (four in the present embodiment) lower fins 138. The base portion 134 has a flat plate shape extending in the vertical direction. The base portion 134 has a fixing hole 140 penetrating the base portion 134 in the left-right direction. In a state where the fixing bolt 142 is inserted into the fixing hole 140 of the base portion 134 and the fixing hole 126 of the inner portion 124, the fixing bolt 142 is threadedly engaged with the base portion 134 and the inner portion 124. Thereby, the base portion 134 comes into contact with the inner portion 124 and is fixed together. The upper end portion of the base portion 134 is disposed at a position above the replenishing opening 100, and the lower end portion of the base portion 134 is disposed at a position below the replenishing opening 100.

[0073] The upper fin 136 has a flat plate shape. The three upper fins 136 are disposed at a position above the fixing hole 140. The three upper fins 136 are arranged in the vertical direction. The wide surfaces of the upper fins 136 face each other with the adjacent upper fins 136. The three upper fins 136 are disposed at a position above the replenishing opening 100 of the fuel tank 50. The three upper fins 136 extend from the left surface of the base portion 134 toward the left side. The three upper fins 136 extend in the left-right direction to a position at a second distance L2 away from the inner surface of the fuel tank 50. The second distance L2 is longer than the first distance L1. The second distance L2 is 10% or more of the length Lo of the fuel tank 50 in the left-right direction. In the present embodiment, the second distance L2 is 40% of the length Lo of the fuel tank 50 in the left-right direction. Further, in the present embodiment, in the left-right direction in which the bolt 82 extends, all of the three upper fins 136 are disposed at a position at 10% or more of the length Lo of the fuel tank 50 in the left-right direction away from the inner surface of the fuel tank 50.

[0074] The lower fins 138 have a flat plate shape. Four lower fins 138 are arranged at a position lower than the fixing holes 140. The four lower fins 138 are arranged in the vertical direction. The wide surfaces of the lower fins 138 face the wide surfaces of the adjacent lower fins 138. The lowermost lower fin 138 is arranged at a position lower than the replenishing opening 100. The four lower fins 138 extend leftward from the left surface of the base 134. The four lower fins 138 extend in the left-right direction to a position at a second distance L2 from the inner surface of the fuel tank 50. In the present embodiment, the second distance L2 is 40% of the length Lo of the fuel tank 50 in the left-right direction. Further, in the present embodiment, in the left-right direction in which the bolt 82 extends, all four lower fins 138 are arranged at positions more than 10% of the length Lo of the fuel tank 50 from the inner surface of the fuel tank 50.

[0075] Next, the positional relationship between the oil level in the fuel tank 50 and the heat dissipation structure 130 will be described. During the operation of the operator using the chain saw 2, the chain saw 2 is in the same posture as when placed on the placement surface P. In this state, the more the amount of oil in the fuel tank 50, the farther the oil level is from the lower surface of the fuel tank 50. As Figure 8 shown, when the amount of oil in the fuel tank 50 is 90% of the capacity of the fuel tank 50, the oil level LH90 is located above the upper end of the uppermost upper fin 136. All three upper fins 136 and four lower fins 138 are arranged in the oil. Further, when the amount of oil is 50% of the capacity of the fuel tank 50, the oil level LH50 is located below the fixing bolt 142 and above the upper end of the lowermost lower fin 138. The four lower fins 138 are arranged in the oil, while the three upper fins 136 are not arranged in the oil. Further, when the amount of oil is 10% of the capacity of the fuel tank 50, the oil level LH10 is located between the upper end and the lower end of the lowermost lower fin 138. A part of the lowermost lower fin 138 is arranged in the oil, while the other three lower fins 138 and three upper fins 136 are not arranged in the oil.

[0076] Further, during the operation of the operator using the chain saw 2, the chain saw 2 is sometimes in a posture with the left housing 10 facing downward (i.e., the replenishing opening 100 facing downward). In this state, the more the amount of oil in the fuel tank 50, the farther the oil level is from the replenishing opening 100. As Figure 6As shown, when the amount of oil in the fuel tank 50 is 50% of the capacity of the fuel tank 50, the oil level LS50 is located at a position farther from the replenishment opening 100 than the top ends of the three upper fins 136 and the top ends of the four lower fins 138. Further, when the amount of oil is 40% of the capacity of the fuel tank 50, the oil level LS40 is located at a position farther from the replenishment opening 100 than the top ends of the three upper fins 136 and the top ends of the four lower fins 138, and a state where a part of the fins 136 and 138 is arranged in the oil can be maintained. In addition, in a modified example, the three upper fins 136 and the four lower fins 138 may also extend to a position closer to the replenishment opening 100 than the oil level when the amount of oil is 10% of the capacity of the fuel tank 50.

[0077] When the saw chain 8 is used to cut a workpiece with the chain saw 2, the guide bar 6 becomes hot due to the frictional heat of the guide bar 6 and the saw chain 8. After that, the heat of the guide bar 6 is transferred to the nut 84 and the bolt 82. As described above, in a state where the chain saw 2 is in the same posture as when it is placed on the placement surface P and the left housing 10 faces downward, at least a part of the three upper fins 136 and the four lower fins 138 is arranged inside the oil in the fuel tank 50. Therefore, the heat of the bolt 82 is dissipated into the oil through the three upper fins 136 and the four lower fins 138. Thereby, it is possible to suppress the nut 84 from becoming hot. In addition, by transferring the heat of the bolt 82 to the oil, the temperature of the oil rises and the viscosity of the oil decreases. For example, even when the chain saw 2 is used in an environment where the outside air temperature is low, such as in winter, the oil with reduced viscosity can be supplied to the saw chain 8.

[0078] (Effect)

[0079] The chain saw 2 of the present embodiment includes: a saw chain 8; a guide bar 6 to which the saw chain 8 is attached; a sprocket 70 that causes the saw chain 8 to travel along the periphery of the guide bar 6; a motor 48 that rotates the sprocket 70; a fuel tank 50 that stores oil supplied to the saw chain 8; a main body housing 22 that houses the motor 48 and the fuel tank 50; a bolt 82 that protrudes from the main body housing 22 and passes through a long hole 6a provided in the guide bar 6; a nut 84 that is threadedly engaged with the bolt 82 to fix the guide bar 6 to the main body housing 22; and a heat dissipation structure 130 that dissipates heat from the bolt 82 into the oil in the fuel tank 50.

[0080] In the above structure, the heat of the nut 84 is transferred to the bolt 82, and the heat dissipation structure 130 dissipates the heat of the bolt 82 into the oil in the fuel tank 50, so it is possible to suppress the bolt 82 from becoming hot. Thereby, it is possible to suppress the nut 84 from becoming hot.

[0081] In addition, as Figure 8As shown, the heat dissipation structure 130 includes a heat dissipation member 132 that contacts the bolt 82, and at least a part of the heat dissipation member 132 is disposed inside the fuel tank 50.

[0082] In the above structure, by bringing at least a part of the heat dissipation member 132 into contact with the oil inside the fuel tank 50, the heat of the heat dissipation member 132 is dissipated into the oil. Therefore, it is possible to suppress the nut 84 from becoming high temperature.

[0083] In addition, the heat dissipation member 132 is a fin 132 made of metal.

[0084] In the above structure, compared with the case where the heat dissipation member 132 does not include fins, the area of contact between the heat dissipation member 132 and the oil inside the fuel tank 50 can be increased. Therefore, the heat of the heat dissipation member 132 is easily dissipated into the oil. Therefore, it is possible to further suppress the nut 84 from becoming high temperature.

[0085] In addition, when an amount of oil equivalent to a first ratio (e.g., 50%) of the capacity of the fuel tank 50 is stored in the fuel tank, in a state where the chainsaw 2 is placed on the ground, the liquid level of the oil is located above the lower end portion of at least a part of the heat dissipation member 132.

[0086] In the above structure, if an amount of oil equivalent to a first ratio of the capacity of the fuel tank 50 is stored in the fuel tank 50, when the chainsaw 2 is set in the same posture as when placed on the placement surface P, the heat dissipation member 132 can contact the oil inside the fuel tank 50. Therefore, the heat of the heat dissipation member 132 can be easily dissipated into the oil. Therefore, it is possible to further suppress the nut 84 from becoming high temperature.

[0087] In addition, even when the amount of oil is 50% or less of the capacity of the fuel tank 50, in a state where the chainsaw 2 is placed on the ground, the liquid level of the oil is located above the lower end portion of at least a part of the heat dissipation member 132.

[0088] During the operation of the chainsaw 2, in order to prevent the oil in the fuel tank 50 from running out, usually, a sufficient amount of oil is stored in the fuel tank 50. However, when the chainsaw 2 is used continuously for a long time, the amount of oil in the fuel tank 50 sometimes decreases to 50% or less of the capacity of the fuel tank 50. In the above structure, even when the chainsaw 2 is used continuously for a long time, when the chainsaw 2 is set in the same posture as when placed on the placement surface P, the heat dissipation member 132 can contact the oil inside the fuel tank 50, and the heat of the heat dissipation member 132 can be easily dissipated into the oil. Therefore, it is possible to further suppress the nut 84 from becoming high temperature.

[0089] In addition, at least a part of the heat dissipation member 132 is disposed inside the fuel tank 50 at a position that is more than 10% of the length Lo away from the inner surface of the fuel tank 50 in the direction in which the bolt 82 extends.

[0090] In the above structure, by disposing at least a part of the heat dissipation member 132 at a deeper position inside the fuel tank 50, the contact area between the heat dissipation member 132 and the oil inside the fuel tank 50 can be increased. Therefore, the heat of the heat dissipation member 132 can be easily dissipated into the oil. As a result, the nut 84 can be further prevented from becoming high temperature.

[0091] In addition, as Figure 3 shown, the guide bar 6 includes a cutting portion 7b located on the tip side of the guide bar 6 in the length direction of the guide bar 6 with respect to the main body housing 22. The length Lg of the cutting portion 7b is 250 mm or less in the length direction.

[0092] Generally, as the length Lg of the cutting portion 7b becomes shorter, the curvature of the periphery of the guide bar 6 becomes larger. Therefore, the frictional heat between the saw chain 8 and the guide bar 6 becomes larger, and the guide bar 6 is likely to become a higher temperature. In the above structure, the heat transferred from the guide bar 6 that becomes a higher temperature to the bolt 82 can be dissipated into the oil inside the fuel tank 50 through the heat dissipation structure 130. Thereby, the nut 84 can be prevented from becoming high temperature.

[0093] The motor 48 can also function as a prime mover.

[0094] In the above structure, compared with the case where the prime mover is an engine, there is less likelihood of a high-temperature portion occurring on the main body housing 22. Therefore, the possibility that an operator accidentally touches the nut 84 is relatively high. In the above structure, since the heat dissipation structure 130 dissipates the heat of the bolt 82 into the oil inside the fuel tank 50, the nut 84 can be prevented from becoming high temperature.

[0095] As Figure 1 shown, the chainsaw 2 further includes a battery pack B that can be detached from and attached to the main body housing 22. The motor 48 is driven by the power from the battery pack B.

[0096] In the above structure, since there is no need for a power cord, the operability of the chainsaw 2 is better. However, the possibility that an operator accidentally touches the nut 84 is relatively high. In the above structure, since the heat dissipation structure 130 dissipates the heat of the bolt 82 into the oil inside the fuel tank 50, the nut 84 can be prevented from becoming high temperature.

[0097] (Second Embodiment)

[0098] Referring to Figure 9 and Figure 10To describe the second embodiment. In the second embodiment, only the differences from the first embodiment will be described, and for the parts that are the same as the first embodiment, the same reference numerals will be used and the description will be omitted. In the second embodiment, the structure of the heat dissipation structure 230 is different from that of the heat dissipation structure 130 in the first embodiment. As Figure 9 shown, the heat dissipation structure 230 includes a heat dissipation member 232 and a fixing bolt 242. The heat dissipation member 232 is composed of a flexible member. Hereinafter, the flexible member will be denoted by the same reference numeral as the heat dissipation member 232 and described. The flexible member 232 is made of a metal material. As the metal material, for example, a material with high heat transfer performance such as aluminum is used. The flexible member 232 is disposed inside the fuel tank 50. The flexible member 232 includes a base portion 234 and a chain portion 236. The base portion 234 has a fixing hole 240 penetrating the base portion 234 in the left-right direction at the central portion in the up-down direction. In a state where the fixing bolt 242 is inserted into the fixing hole 240 of the base portion 234 and the fixing hole 126 of the inner portion 124, the fixing bolt 242 is threadedly engaged with the base portion 234 and the inner portion 124. Thus, the base portion 234 contacts and is fixed to the inner portion 124.

[0099] The chain portion 236 is fixed to the lower portion of the base portion 234. The chain portion 236 has a shape formed by connecting a plurality of metal rings. Regardless of the posture of the chainsaw 2, the chain portion 236 hangs down along the direction of gravity. For example, as Figure 9 shown, when the chainsaw 2 is in the same posture as when placed on the placement surface P, the chain portion 236 hangs down toward the lower surface of the fuel tank 50, and a part of the chain portion 236 contacts the lower surface of the fuel tank 50. In this state, even when the amount of fuel in the fuel tank 50 is 10% of the capacity of the fuel tank 50, the oil level LH10 is located above a part of the chain portion 236. Therefore, a part of the chain portion 236 is disposed in the oil. As a result, the heat of the bolt 82 is dissipated to the oil through the chain portion 236, and the nut 84 can be prevented from becoming high temperature.

[0100] In addition, as Figure 10 shown, when the replenishment opening 100 faces downward, the chain portion 236 hangs down toward the replenishment opening 100, and a part of the chain portion 236 contacts the inner surface on the side of the replenishment opening 100 of the fuel tank 50. Therefore, even when the amount of fuel in the fuel tank 50 is 10% of the capacity of the fuel tank 50, the oil level LS10 is located at a position away from the replenishment opening 100 from a part of the chain portion 236. As a result, the heat of the bolt 82 is dissipated to the oil through the chain portion 236 disposed in the oil, and the nut 84 can be prevented from becoming high temperature.

[0101] (Effect)

[0102] The heat dissipation member 232 is a flexible member 232 made of metal that hangs down in the direction of gravity regardless of the posture of the chain saw 2.

[0103] In the above structure, regardless of the posture of the chain saw 2, the flexible member 232 can come into contact with the oil in the fuel tank 50. Therefore, the heat of the heat dissipation member 232 is easily dissipated into the oil. As a result, it is possible to further suppress the nut 84 from becoming high temperature.

[0104] (Third Embodiment)

[0105] Refer to Figure 11 and Figure 12 to describe the third embodiment. In the third embodiment, only the differences from the first embodiment will be described, and for the parts that are the same as those in the first embodiment, the same reference numerals will be used and the description will be omitted. As Figure 11 shown, in the third embodiment, the inner part 124 of the bolt 82 constitutes a heat dissipation structure 130. The inner part 124 extends in the left-right direction in which the fixing part 122 of the bolt 82 extends to a position that is at a first distance L1 away from the inner surface of the fuel tank 50. Here, the first distance L1 is 10% or more of the width W of the fuel tank 50 in the left-right direction, and in this embodiment, it is 40% of the length Lo. The upper end portion of the inner part 124 is disposed at a position above the upper end portion of the replenishment opening 100 of the fuel tank 50, and the lower end portion of the inner part 124 is disposed at a position below the upper end portion of the replenishment opening 100 and above the lower end portion of the replenishment opening 100.

[0106] When the chain saw 2 is in the same posture as when it is placed on the placement surface P, and when the amount of oil in the fuel tank 50 is 50% of the capacity of the fuel tank 50, the liquid level LH50 of the oil is disposed at a position above the lower end portion of the inner part 124. Therefore, a part of the inner part 124 is disposed inside the oil. As a result, the heat of the bolt 82 is dissipated into the oil through the inner part 124, and it is possible to suppress the nut 84 from becoming high temperature.

[0107] In addition, as Figure 12 shown, when the replenishment opening 100 faces downward and the amount of oil in the fuel tank 50 is 50% of the capacity of the fuel tank 50, the liquid level LS50 of the oil is located at a position away from the replenishment opening 100 by a distance greater than the top end portion of the inner part 124. In addition, when the amount of oil is 40% of the capacity of the fuel tank 50, the liquid level LS40 of the oil is located at a position away from the replenishment opening 100 by a distance greater than the top end portion of the inner part 124, and it is possible to maintain the state where a part of the inner part 124 is disposed inside the oil. In addition, in a modified example, the inner part 124 may also extend to a position below the liquid level of the oil when the amount of oil is 10% of the capacity of the fuel tank 50.

[0108] (Effect)

[0109] The bolt 82 penetrates the fuel tank 50 from the outside to the inside. The inner portion 124 of the bolt 82 in the fuel tank 50 constitutes a heat dissipation structure 130. The inner portion 124 of the bolt 82 in the fuel tank 50 includes a portion that is disposed inside the fuel tank 50 at a position more than 10% of the length Lo away from the inner surface of the fuel tank 50 in the extending direction of the bolt 82.

[0110] In the above structure, by disposing the bolt 82 at a deeper position inside the fuel tank 50, the contact area between the bolt 82 and the oil in the fuel tank 50 can be increased, so that the heat of the bolt 82 can be easily dissipated into the oil. Thus, the nut 84 can be further inhibited from becoming high temperature.

[0111] In addition, when an amount of oil equivalent to a first ratio (e.g., 50%) of the capacity of the fuel tank 50 is stored in the fuel tank 50, in a state where the chainsaw 2 is placed on the ground, the liquid level of the oil is located at a position above the lower end portion of the inner portion of the bolt 82 in the fuel tank 50.

[0112] In the above structure, if an amount of oil equivalent to a first ratio of the capacity of the fuel tank 50 is stored in the fuel tank 50, when the chainsaw 2 is in the same posture as when placed on the placement surface P, the bolt 82 can contact the oil in the fuel tank 50, so that the heat of the bolt 82 can be easily dissipated into the oil. Thus, the nut 84 can be further inhibited from becoming high temperature.

[0113] In addition, even when the amount of oil is less than 50% of the capacity of the fuel tank 50, in a state where the chainsaw 2 is placed on the ground, the liquid level of the oil is located at a position above at least a part of the lower end portion of the heat dissipation member 232.

[0114] In the above structure, even when the chainsaw 2 is continuously used for a long time and the amount of oil in the fuel tank 50 is reduced to less than 50% of the capacity of the fuel tank 50, when the chainsaw 2 is in the same posture as when placed on the placement surface P, the bolt 82 can contact the oil, and the heat of the bolt 82 can be easily dissipated into the oil. Thus, the nut 84 can be further inhibited from becoming high temperature.

[0115] In addition, in this embodiment, the heat of the bolt 82 can be dissipated into the oil only by the bolt 82. Thus, the number of components can be reduced.

[0116] Alternatively, the fixing portion 122 of the bolt 82 in one embodiment may extend from the outer portion 120 toward the left, then bend and extend downward, and then further bend and extend toward the left. In this case, the inner portion 124 may also extend in the left - right direction near the lower surface of the fuel tank 50.

[0117] Alternatively, the bolt 82 of one embodiment may only include the outer portion 120 and the fixing portion 122. In this case, the heat dissipation structures 130, 230 may be directly fixed to the fixing portion 122. Additionally, it may also be that through insert molding, both the bolt 82 and the heat dissipation structures 130, 230 are fixed to the right housing 12. In this case, a part of the heat dissipation structures 130, 230 may also be buried inside the right housing 12.

[0118] The chain saw 2 of one embodiment may also be an engine-driven chain saw.

[0119] Alternatively, the chain saw 2 of one embodiment may not include the battery pack B. In this case, the chain saw 2 may also be structured to supply power to the motor 48 from an external power source via a power cord.

Claims

1. A chainsaw, wherein, the chainsaw comprises: a saw chain; a guide bar on which the saw chain is mounted; a sprocket that causes the saw chain to travel along the circumference of the guide bar; a prime mover that rotates the sprocket; a fuel tank that stores oil supplied to the saw chain; a housing that houses the prime mover and the fuel tank; a bolt that protrudes from the housing and passes through a hole provided in the guide bar; a nut that is threadedly engaged with the bolt to fix the guide bar to the housing; and a heat dissipation structure that dissipates heat from the bolt into the oil in the fuel tank, the heat dissipation structure includes a heat dissipation member that contacts the bolt, and at least a part of the heat dissipation member is disposed inside the fuel tank, the heat dissipation member includes a flexible member made of metal, and the flexible member hangs down along the direction of gravity regardless of the posture of the chainsaw.

2. The chainsaw according to claim 1, wherein, when an amount of the oil equivalent to a first ratio of the capacity of the fuel tank is stored in the fuel tank, in a state where the chainsaw is placed on the ground, the liquid level of the oil is located at a position above the lower end portion of at least a part of the heat dissipation member.

3. The chainsaw according to claim 2, wherein, the first ratio is 50% or less of the capacity of the fuel tank.

4. The chainsaw according to any one of claims 1 to 3, wherein, at least a part of the heat dissipation member includes a part disposed inside the fuel tank at a position that is 10% or more of the length of the fuel tank away from the inner surface of the fuel tank in the extending direction of the bolt.

5. The chainsaw according to any one of claims 1 to 3, wherein, the guide bar includes a cutting portion located on the tip side of the guide bar with respect to the housing in the length direction of the guide bar, and the length of the cutting portion is 250 mm or less in the length direction.

6. The chainsaw according to any one of claims 1 to 3, wherein, the prime mover is a motor.

7. The chainsaw according to claim 6, wherein, the chainsaw further includes a battery pack that can be detached from and attached to the housing, and the motor is driven by electric power from the battery pack.

8. A chainsaw, wherein, the chainsaw comprises: a saw chain; a guide bar on which the saw chain is mounted; a sprocket that causes the saw chain to travel along the circumference of the guide bar; a prime mover that rotates the sprocket; a fuel tank that stores oil supplied to the saw chain; a housing that houses the prime mover and the fuel tank; a bolt that protrudes from the housing and passes through a hole provided in the guide bar; a nut that is threadedly engaged with the bolt to fix the guide bar to the housing; and a heat dissipation structure that dissipates heat from the bolt into the oil in the fuel tank, the bolt passes through the fuel tank from the outside to the inside, and the part of the bolt inside the fuel tank constitutes the heat dissipation structure, and the part of the bolt inside the fuel tank includes a part disposed inside the fuel tank at a position that is 10% or more of the length of the fuel tank away from the inner surface of the fuel tank in the extending direction of the bolt.

9. The chain saw according to claim 8, wherein, when an amount of oil corresponding to a first ratio of the capacity of the fuel tank is stored in the fuel tank, in a state where the chain saw is placed on the ground, a liquid level of the oil is located at a position above a lower end portion of the portion inside the fuel tank of the bolt.

10. The chain saw according to claim 9, wherein, the first ratio is 50% or less of the capacity of the fuel tank.

11. The chain saw according to any one of claims 8 to 10, wherein, the guide bar includes a cutting portion located on a side of a tip end portion of the guide bar closer to the tip end portion than the housing in a length direction of the guide bar, and a length of the cutting portion is 250 mm or less in the length direction.

12. The chain saw according to any one of claims 8 to 10, wherein, the prime mover is a motor.

13. The chain saw according to claim 12, wherein, the chain saw further includes a battery pack that can be detached from and attached to the housing, and the motor is driven by electric power from the battery pack.

Images