Chainsaw

Abstract

This invention provides a technology that can prevent sawdust from clogging the chain passage in chain oil-free chainsaws. [Solution] The chain oil-free type chainsaw comprises a guide bar, a sprocket, a saw chain, an electric motor, a housing, and a sprocket cover. When the chainsaw is viewed from the side, the straight line passing through the center position of the saw chain at the point where the saw chain separates from the guide bar below the guide bar, and the center position of the saw chain at the point where the saw chain engages with the sprocket below the sprocket, is defined as the first reference straight line. The position where the first reference straight line intersects the opposing surface is defined as the first reference position, and the inclination angle of the opposing surface with respect to the front-rear direction at the first reference position is 90° or more.

Description

Technical Field

[0001] The technology disclosed in the present specification relates to a chainsaw.

Background Art

[0002] Patent Document 1 discloses a chainsaw. The chainsaw includes a guide bar arranged such that its central axis extends along the front-rear direction, a sprocket disposed rearward of the guide bar such that its rotation axis extends along the left-right direction, a saw chain stretched around the guide bar and the sprocket, an electric motor that rotates the sprocket about the rotation axis, a housing that accommodates the electric motor, and a sprocket cover that covers the sprocket. As the sprocket rotates, the saw chain moves from below the guide bar to below the sprocket, moves from below the sprocket around the rear of the sprocket to above the sprocket, moves from above the sprocket to above the guide bar, and travels so as to move from above the guide bar around the front of the guide bar to below the guide bar. The sprocket, the housing, and the sprocket cover form a chain passage through which the saw chain passes. In the chain passage, the housing has an opposing surface that faces the sprocket in the radial direction of the sprocket. When the chainsaw is viewed from the side, a straight line passing through the center position of the saw chain at the location where the saw chain separates from the guide bar below the guide bar and the center position of the saw chain at the location where the saw chain engages with the sprocket below the sprocket is defined as a first reference straight line, the position where the first reference straight line intersects the opposing surface is defined as a first reference position, and the inclination angle of the opposing surface at the first reference position with respect to the front-rear direction is less than 90°.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0004] In so-called chain oil-free chainsaws, which allow cutting operations without applying lubricating oil between the saw chain and guide bar, chips tend to clog the chain passage. This specification provides a technology that can suppress the clogging of chips in the chain passage in chain oil-free chainsaws. [Means for solving the problem]

[0005] The chain oil-free chainsaw disclosed herein may include a guide bar whose central axis is positioned along the front-rear direction, a sprocket positioned behind the guide bar with its rotation axis positioned along the left-right direction, a saw chain stretched between the guide bar and the sprocket, an electric motor for rotating the sprocket around the rotation axis, a housing for the electric motor, and a sprocket cover covering the sprocket. The saw chain may travel in conjunction with the rotation of the sprocket, moving from below the guide bar to below the sprocket, moving from below the sprocket around the rear of the sprocket to above the sprocket, moving from above the sprocket to above the guide bar, and moving from above the guide bar around the front of the guide bar to below the guide bar. The sprocket, the housing, and the sprocket cover may form a chain passage through which the saw chain passes. In the chain passage, at least one of the housing and the sprocket cover may have an opposing surface facing the sprocket in the radial direction of the sprocket. When the chainsaw is viewed from the side, the first reference line may be a straight line passing through the center position of the saw chain at the point where the saw chain separates from the guide bar below the guide bar, and the center position of the saw chain at the point where the saw chain engages with the sprocket below the sprocket. The first reference position may be the position where the first reference line intersects the opposing surface, and the inclination angle of the opposing surface with respect to the front-rear direction at the first reference position may be 90° or more. A chain oil-free type chainsaw as used herein refers to a chainsaw that can perform cutting work without applying lubricating oil between the saw chain and the guide bar, although oil may be applied to other mechanical parts such as bearings.

[0006] When cutting with a chainsaw, the chips generated move along the saw chain below the guide bar from front to back. Then, when the saw chain separates from the guide bar and engages with the sprocket, the chips fly backward along a trajectory that roughly coincides with the first reference line. The chips that fly backward hit the area near the first reference position on the opposing surface. If the chips that hit the opposing surface were to bounce upward, they would move along with the saw chain to the upper side of the chain passage and could become stuck in the chain passage. With the above configuration, the inclination angle of the opposing surface with respect to the front-to-back direction at the first reference position is 90° or more, which prevents the chips that hit the opposing surface from bouncing upward. This prevents the chips from moving to the upper side of the chain passage and becoming stuck in the chain passage. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view of the chainsaw 2 according to the embodiment, taken from the front left and above. [Figure 2] This is a perspective view showing a portion of the saw chain 6 according to the embodiment. [Figure 3] This is a perspective view of the chainsaw 2 according to the embodiment, taken from the rear right and above. [Figure 4] This is a perspective view from the rear left upper side of the chainsaw 2 according to the embodiment, with the sprocket cover 18 removed. [Figure 5] This is a cross-sectional view of the chainsaw 2 according to the embodiment, seen from the left. [Figure 6] This is a perspective view of the chainsaw 2 according to the embodiment, showing the electric motor 64, motor shaft 80, cooling fan 82, reduction gear 72, drive shaft 84, sprocket 26, guide bar 4, and saw chain 6 from the front right and above. [Figure 7] This is a cross-sectional view of the vicinity of the sprocket 26 of the chainsaw 2 according to the embodiment, viewed from the left. [Figure 8]This is a perspective view of the sprocket cover 18 according to the embodiment, seen from the rear left and above. [Figure 9] This is a perspective view of the sprocket cover 18 according to the embodiment, viewed from the front right and above. [Figure 10] This is a schematic diagram showing the relationship between the opposing surface 18a and the inclination angles θ, φ, and ψ in the embodiment. [Modes for carrying out the invention]

[0008] Hereinafter, representative and non-limiting examples of the present invention will be described in detail with reference to the drawings. This detailed description is simply intended to show those skilled in the art details for carrying out preferred examples of the present invention and is not intended to limit the scope of the present invention. Furthermore, the disclosed additional features and inventions may be used separately from or in conjunction with other features and inventions to provide a further improved chainsaw.

[0009] Furthermore, the combinations of features and processes disclosed in the following detailed description are not essential for carrying out the present invention in the broadest sense, and are described solely to illustrate representative examples of the present invention. Moreover, the various features of the representative examples described above and below, as well as the various features described in the independent and dependent claims, do not necessarily have to be combined in the same way as the examples described herein or in the order listed, in order to provide additional and useful embodiments of the present invention.

[0010] All features described herein and / or in the claims are intended to be disclosed individually and independently of each other, as limitations to the original disclosure and claimed specific subject matter, separate from the features described in the examples and / or claims. Furthermore, all descriptions of numerical ranges and groups or clusters are intended to disclose intermediate configurations as limitations to the original disclosure and claimed specific subject matter.

[0011] In one or more embodiments, when the chainsaw is viewed from the side, an inclination angle of the opposing surface at the first reference position with respect to the first reference straight line may be 90° or more.

[0012] According to the above configuration, it is possible to more effectively suppress the chips that collide with the opposing surface from rebounding upward.

[0013] In one or more embodiments, when the chainsaw is viewed from the side, an inclination angle of the opposing surface at the first reference position with respect to the front-rear direction may be 120° or less.

[0014] If the inclination angle of the opposing surface at the first reference position with respect to the front-rear direction exceeds 120°, the size of the housing and the sprocket cover increases in the front-rear direction, and the size of the chainsaw in the front-rear direction increases. According to the above configuration, the size of the housing and the sprocket cover can be reduced in the front-rear direction, and the size of the chainsaw in the front-rear direction can be reduced.

[0015] In one or more embodiments, when the chainsaw is viewed from the side, a straight line extending in the front-rear direction passing through the center position of the saw chain at the lowermost end of the guide bar may be defined as a second reference straight line, a position where the second reference straight line intersects the opposing surface may be defined as a second reference position, and the second reference position may be located in a range from directly below the first reference position to the rear.

[0016] Chips that fly rearward when the saw chain separates from the guide bar and engages with the sprocket move under the influence of gravity, and thus collide not only with the first reference position of the opposing surface but also with a certain range below the first reference position of the opposing surface. According to the above configuration, the opposing surface in a certain range where chips are likely to collide can be set to an angle that makes it difficult to rebound to the upper side of the chain passage.

[0017] In one or more embodiments, when the chainsaw is viewed from the side, between the first reference position and the second reference position, the opposing surface does not need to have a shape that protrudes more toward the chain passage side than the straight line connecting the first reference position and the second reference position.

[0018] According to the above configuration, chips that have collided with the opposing surface can be easily discharged downward.

[0019] In one or more embodiments, the housing or the sprocket cover is disposed below the sprocket, and includes a discharge port for discharging chips from the chain passage, and a rear end of the discharge port may be located in a range from directly below the first reference position to the rear.

[0020] According to the above configuration, chips that have collided with the opposing surface can be easily discharged from the discharge port.

[0021] In one or more embodiments, the discharge port may have a shape in which the width in the left-right direction increases from the upper side toward the lower side.

[0022] According to the above configuration, the chip discharge performance from the discharge port can be improved.

[0023] In one or more embodiments, the number of teeth of the sprocket may be 9 or more.

[0024] At the point where the saw chain separates from the guide bar and engages with the sprocket, a large tension acts on the saw chain. If the sprocket has few teeth, the bending angle of the saw chain becomes large at the point where the saw chain separates from the guide bar and engages with the sprocket, i.e., at the point where a large tension acts on the saw chain, and the connection point between the drive link and the connecting pin of the saw chain becomes prone to wear. With the above configuration, since the sprocket has nine or more teeth, the bending angle of the saw chain can be reduced at the point where the saw chain separates from the guide bar and engages with the sprocket, i.e., at the point where a large tension acts on the saw chain, and wear on the connection point between the drive link and the connecting pin of the saw chain can be suppressed.

[0025] In one or more embodiments, the guide bar may be a guide bar in which a sprocket is not incorporated into the tip portion.

[0026] In guide bars with a sprocket at the tip, when the connection point between the drive link and connecting pin of the saw chain wears down and the saw chain stretches, the meshing between the sprocket and drive link at the tip of the guide bar becomes poor, which can easily generate abnormal noise. With the above configuration, by using a guide bar without a sprocket at the tip, it is possible to suppress the generation of abnormal noise even when the connection point between the drive link and connecting pin of the saw chain wears down and the saw chain stretches.

[0027] In one or more embodiments, the speed at which the saw chain travels may be 9 m / s or less.

[0028] The faster the saw chain travels, the more easily it wears out. With the above configuration, by keeping the saw chain travel speed below 9 m / s, wear on the saw chain can be suppressed.

[0029] (Examples) As shown in Figure 1, the chainsaw 2 in this embodiment is a so-called pruning saw, which is mainly used for cutting wood, tree branches, etc., while being held by the user with one hand.

[0030] The chainsaw 2 comprises a guide bar 4, a saw chain 6, a housing 8, a chain cover 10, a sprocket cover 18, and a battery pack B. The chainsaw 2 uses power supplied from the battery pack B to move the saw chain 6 along the periphery of the guide bar 4. For example, the speed at which the saw chain 6 moves along the periphery of the guide bar 4 is 9 m / s or less. The chainsaw 2 is a chain oil-free type chainsaw that can perform cutting work without applying lubricating oil between the guide bar 4 and the saw chain 6.

[0031] The guide bar 4 is an elongated, plate-shaped member attached to the housing 8 so as to protrude forward from the housing 8. The guide bar 4 has a vertical bulge around the center of its longitudinal direction to improve cutting performance. The guide bar 4 is, for example, a guide bar 4 without a sprocket incorporated at its tip. The longitudinal dimension of the guide bar 4 is in the range of 50 mm to 256 mm, for example, 150 mm. The short-side dimension of the guide bar 4 is in the range of 30 mm to 70 mm, for example, 50 mm. In this embodiment, the longitudinal direction of the guide bar 4 is defined as the front-rear direction, the direction from the base end to the tip of the guide bar 4 is defined as the forward direction, and the opposite direction of the forward direction is defined as the rear direction. Furthermore, the short-side direction of the guide bar 4 is defined as the up-down direction, the direction in which the saw chain 6 travels at the tip of the guide bar 4 is defined as the down direction, and the opposite direction of the down direction is defined as the up direction. Finally, the thickness direction of the guide bar 4 is defined as the left-right direction, in a direction perpendicular to the front-rear and up-down directions. Furthermore, the straight line that passes through the center position of the guide bar 4 in the vertical and horizontal directions and extends in the front-to-back direction is also called the central axis of the guide bar 4.

[0032] As shown in Figure 2, the saw chain 6 comprises a plurality of drive links 602 arranged along the direction of travel of the saw chain 6 and received in grooves (not shown) on the periphery of the guide bar 4; tie straps 610 positioned on both the left and right sides of the plurality of drive links 602; a plurality of side links 604 positioned on both the left and right sides of the plurality of drive links 602 and having cutting portions 608; and a plurality of connecting pins 606 that connect each of the plurality of drive links 602 to each of the plurality of side links 604 or the plurality of tie straps 610. In this specification, the center of the saw chain 6 refers to the center of the connecting pins 606.

[0033] As shown in Figure 3, the housing 8 comprises a gear housing 12, a motor housing 14, a grip 16, a battery pack mounting section 17, and a handguard 20. As shown in Figure 4, the gear housing 12, together with the sprocket cover 18, holds the base end of the guide bar 4. The motor housing 14 extends upward and rearward from the rear upper part of the gear housing 12. The grip 16 extends downward and rearward from the rear lower part of the motor housing 14. The grip 16 has a substantially cylindrical cross-sectional shape. The battery pack mounting section 17 is provided at the rear end of the grip 16. The handguard 20 has a wide, flat shape, with its front end connected to the rear lower end of the gear housing 12 and its rear end connected to the front lower end of the battery pack mounting section 17.

[0034] As shown in Figure 4, a trigger lever 50 for the user to operate the saw chain 6 is located on the underside near the front end of the grip 16. The user can pull the trigger lever 50 toward the grip 16. Inside the grip 16 is a trigger switch (not shown) that detects the user's pulling operation of the trigger lever 50. The trigger switch is electrically connected to a control unit 60, which will be described later.

[0035] As shown in Figure 3, the handguard 20 is a protective device that covers the user's hand gripping the grip 16 from below, thereby protecting the user's hand. If the saw chain 6 breaks while the user is performing a cutting operation (while the saw chain 6 is being driven), the broken saw chain 6 may fly out from the guide bar 4 while maintaining its momentum. In such a case, the handguard 20 can prevent the saw chain 6 that has flown out from the guide bar 4 from coming into contact with the user's hand gripping the grip 16.

[0036] The battery pack mounting section 17 allows for the attachment and removal of the battery pack B. The battery pack B houses a rechargeable secondary battery, such as a lithium-ion battery. The output voltage of the battery pack B is, for example, 10V. The battery capacity of the battery pack B is, for example, 1.5Ah. As shown in Figure 5, the battery pack B can be attached to the battery pack mounting section 17 by sliding it from the rear upper to the front lower, and can be removed from the battery pack mounting section 17 by sliding it from the front lower to the rear upper. A control unit 60 is housed inside the battery pack mounting section 17. When the battery pack B is attached to the battery pack mounting section 17, it is electrically connected to the control unit 60.

[0037] The motor housing 14 houses an electric motor 64 and a cooling fan 82. The electric motor 64 is, for example, an inner rotor type DC brushless motor. The electric motor 64 comprises a stator 76 around which a coil 74 is wound, and a rotor (not shown) located inside the stator 76 and equipped with permanent magnets. A motor shaft 80 is fixed to the rotor. The motor shaft 80 is arranged along a plane extending in the front-rear and up-down directions. The motor shaft 80 is inclined in the up-down direction, from front to rear as it moves from bottom to top. The motor shaft 80 is rotatably supported in the motor housing 14 via a plurality of bearings 86 (see Figure 6). Even if the chainsaw 2 is a chain oil-free type chainsaw 2, the bearings 86 may be filled with lubricating oil.

[0038] The cooling fan 82 is fixed to the motor shaft 80 in front of and below the stator 76 and rotor of the electric motor 64. The cooling fan 82 rotates in conjunction with the rotation of the motor shaft 80. When the cooling fan 82 rotates, an airflow is formed along the motor shaft 80 from the rear upper part to the front lower part. At this time, air is drawn in from the outside to the inside of the motor housing 14 through the intake ports 142 formed on the upper rear and rear upper parts of the motor housing 14, and air is discharged from the inside to the outside of the motor housing 14 through the exhaust port 140 (see Figure 1) formed on the lower left side of the motor housing 14. This airflow can cool the electric motor 64.

[0039] A reduction gear 72 (see Figure 6) is housed inside the gear housing 12. As shown in Figure 6, the reduction gear 72 comprises a first bevel gear 72a and a second bevel gear 72b. The first bevel gear 72a is fixed to the motor shaft 80 in front of and below the cooling fan 82. The second bevel gear 72b is fixed to the drive shaft 84. The drive shaft 84 is arranged along the left-right direction. The drive shaft 84 is rotatably supported in the gear housing 12 (see Figure 5) via a number of bearings 86. The reduction gear 72 transmits the rotation of the motor shaft 80 to the drive shaft 84 by the meshing of the first bevel gear 72a and the second bevel gear 72b. As a result, the drive shaft 84 rotates around the rotation axis RX.

[0040] As shown in Figure 4, the left end of the drive shaft 84 protrudes to the left from the left surface of the gear housing 12. A sprocket 26 is fixed to the left end of the drive shaft 84 outside the gear housing 12. As shown in Figure 7, in this embodiment, the sprocket 26 has, for example, nine teeth. As shown in Figure 6, the saw chain 6 is stretched between the guide bar 4 and the sprocket 26. Therefore, when the electric motor 64 is driven, the rotational motion of the motor shaft 80 is transmitted to the drive shaft 84 via the reduction gear 72, causing the sprocket 26 to rotate around the rotation axis RX, and the saw chain 6 to travel around the periphery of the guide bar 4.

[0041] As shown in Figure 5, the control unit 60 includes a control board (not shown) equipped with an inverter circuit having multiple switching elements and a control circuit that controls the operation of each switching element. The control unit 60 can control the operation of the electric motor 64 by adjusting the power supplied from the battery pack B to the electric motor 64.

[0042] As shown in Figure 3, the chain cover 10 is positioned to cover the upper and right upper halves of the guide bar 4. As shown in Figure 4, the chain cover 10 is mounted on the gear housing 12 so as to be rotatable around the pivot axis 10a. The chain cover 10 is rotatable between a normal position with its tip rotated downward (see Figure 4) and a retracted position with its tip rotated upward (not shown). The chain cover 10 is biased from the retracted position to the normal position by a torsion spring (not shown).

[0043] The guide bar 4 has a notch 4a that extends forward from its rear end. A pin 28 and a bolt 32 are positioned in the notch 4a, protruding to the left from the left surface of the gear housing 12. The left end of the pin 28 is located to the right of the left surface of the guide bar 4. The left end of the bolt 32 protrudes to the left of the left surface of the guide bar 4.

[0044] The sprocket cover 18 comprises a sprocket cover body 36 and a locking member 42. The sprocket cover body 36 has a through hole 38 through which a bolt 32 can pass and an outlet 40 that opens downward. As shown in Figure 8, the outlet 40 has a shape in which the width in the left-right direction increases from top to bottom. As shown in Figure 4, the locking member 42 comprises a locking member body 44, a nut 46 fixed to the locking member body 44 into which the bolt 32 is screwed, and a claw portion 48 for the user to rotate the locking member body 44.

[0045] The sprocket cover 18 can be attached to the gear housing 12 by screwing the nut 46 of the locking member 42 onto the bolt 32 that passes through the through hole 38 of the sprocket cover body 36. When the nut 46 is tightened on the bolt 32, the guide bar 4 is sandwiched and fixed between the gear housing 12 and the sprocket cover 18. When the nut 46 is loosened on the bolt 32, the guide bar 4 can be slid in the front-rear direction relative to the gear housing 12, and the tension of the saw chain 6 can be adjusted by changing the distance between the guide bar 4 and the sprocket 26. The user can tighten or loosen the nut 46 on the bolt 32 without using any special tools by rotating the claw portion 48, which is erected to the left relative to the locking member body 44, around the axis of the bolt 32. As shown in Figure 1, the claw portion 48 is normally held in a reclined position along the locking member body 44 by a torsion spring (not shown).

[0046] As shown in Figure 7, a chain passage 99 is formed between the sprocket 26, the gear housing 12, and the sprocket cover 18 through which the saw chain 6 passes. As shown in Figure 9, the sprocket cover 18 has an opposing surface 18a. As shown in Figure 7, in the chain passage 99, the opposing surface 18a faces the saw chain 6 in the radial direction of the sprocket 26. Note that the opposing surface 18a may be provided on the gear housing 12 instead of the sprocket cover 18.

[0047] As the sprocket 26 rotates, the saw chain 6 moves around the guide bar 4 and the sprocket 26. Specifically, focusing on one of the connecting pins 606 of the saw chain 6 located below the guide bar 4, the connecting pin 606 moves from below the guide bar 4 to below the sprocket 26. Then, the connecting pin 606 moves from below the sprocket 26, around the rear of the sprocket 26, and above the sprocket 26. After that, the connecting pin 606 moves from above the sprocket 26 to above the guide bar 4, and then from above the guide bar 4, around the front of the guide bar 4, and below the guide bar 4. As the sprocket 26 rotates, the saw chain 6 (connecting pin 606) repeats the above series of rotations across the guide bar 4 and the sprocket 26.

[0048] The saw chain 6 below the guide bar 4 separates from the guide bar 4 at point C1. More specifically, point C1, where the saw chain 6 separates from the guide bar 4, can be defined as the point where the angle between the tangential direction of the guide bar 4 and the direction of travel of the saw chain 6 is 0.5° or more. After separating from the guide bar 4, the saw chain 6 engages with the sprocket 26 at point C2. Here, point C2, where the saw chain 6 engages with the sprocket 26, can be defined as the point where the angle between the tangential direction of rotation of the sprocket 26 and the direction of travel of the saw chain 6 is 5° or less. When viewing the chainsaw 2 from the left, the first reference line L1 is defined as the straight line passing through the center position of the saw chain 6 at point C1 where the saw chain 6 separates from the guide bar 4 below the guide bar 4 (i.e., the center position of the connecting pin 606) and the center position of the saw chain 6 at point C2 where the saw chain 6 engages with the sprocket 26 below the sprocket 26 (i.e., the center position of the connecting pin 606). Furthermore, the position where the first reference line L1 intersects with the opposing surface 18a is defined as the first reference position P1. In this case, the inclination angle θ of the opposing surface 18a with respect to the front-rear direction at the first reference position P1 (see Figure 10) is, for example, within the range of 90° to 120°, and is, for example, 90°. Also, the inclination angle φ of the opposing surface 18a with respect to the first reference line L1 at the first reference position P1 (see Figure 10) is, for example, within the range of 70° to 120°, and is, for example, 85°.

[0049] As shown in Figure 7, when the chainsaw 2 is viewed from the left, the straight line extending in the front-rear direction that passes through the center position of the saw chain 6 at the lowest end of the guide bar 4 (i.e., the center position of the connecting pin 606) is defined as the second reference straight line L2. The position where the second reference straight line L2 intersects the opposing surface 18a is defined as the second reference position P2. In this case, the inclination angle ψ of the opposing surface 18a with respect to the front-rear direction at the second reference position P2 (see Figure 10) is, for example, in the range of 90° to 120°, and is, for example, 90°.

[0050] As shown in Figure 7, the second reference position P2 is located in the range from directly below to behind the first reference position P1. Furthermore, between the first reference position P1 and the second reference position P2, the opposing surface 18a does not have a shape that protrudes toward the chain passage 99 side beyond the straight line connecting the first reference position P1 and the second reference position P2. In addition, the rear end 40a of the discharge port 40 provided by the sprocket cover 18 is located in the range from directly below to behind the first reference position P1. Note that the rear end 40a of the discharge port 40 is located behind the rear end of the sprocket 26, and the front end 40b of the discharge port 40 is located in front of the front end of the sprocket 26.

[0051] (modified version) In the above embodiment, the chainsaw 2 was described as a pruning saw that could be held and used by the user with one hand. In another embodiment, the chainsaw 2 may be a top-handle chainsaw or a rear-handle chainsaw that can be held and used by the user with both hands.

[0052] In the above embodiment, a configuration was described in which the chainsaw 2 is equipped with a detachable battery pack B. In another embodiment, the chainsaw 2 may not be equipped with a battery pack B and may be powered by an external power source via a cable.

[0053] In the above embodiment, a configuration was described in which the speed at which the saw chain 6 travels along the periphery of the guide bar 4 is 9 m / s or less. In another embodiment, the speed at which the saw chain 6 travels along the periphery of the guide bar 4 may be faster than 9 m / s.

[0054] In the above embodiment, a configuration was described in which the guide bar 4 is a guide bar 4 in which a sprocket is not incorporated into the tip portion. In another embodiment, the guide bar 4 may be a guide bar 4 in which a sprocket is incorporated into the tip portion.

[0055] In the above embodiment, a configuration in which the electric motor 64 is an inner rotor type DC brushless motor was described. In another embodiment, the electric motor 64 may be an outer rotor type DC brushless motor. Alternatively, the electric motor 64 may be a brushed motor or another type of electric motor.

[0056] In the above embodiment, a configuration in which the sprocket 26 has 9 teeth was described. In another embodiment, the sprocket 26 may have 10 or more teeth, or 8 or fewer teeth.

[0057] In the above embodiment, a configuration was described in which the inclination angle θ (see Figure 10) of the opposing surface 18a with respect to the front-rear direction at the first reference position P1 is 120° or less. In another embodiment, the inclination angle θ may exceed 120°.

[0058] In the above embodiment, a configuration was described in which the inclination angle φ (see Figure 10) of the opposing surface 18a at the first reference position P1 with respect to the first reference line L1 is 90° or more. In another embodiment, the inclination angle φ may be less than 90°.

[0059] In the above embodiment, a configuration was described in which the second reference position P2 is located in the range from directly below to behind the first reference position P1. In another embodiment, the second reference position P2 may be located in the range from directly below to in front of the first reference position P1.

[0060] In the above embodiment, a configuration was described in which the opposing surface 18a does not have a shape that protrudes toward the chain passage 99 side beyond the straight line connecting the first reference position P1 and the second reference position P2. In another embodiment, the opposing surface 18a may have a shape that protrudes toward the chain passage 99 side beyond the straight line connecting the first reference position P1 and the second reference position P2.

[0061] In the above embodiment, a configuration was described in which the rear end 40a of the discharge port 40 is located in the range from directly below to behind the first reference position P1. In another embodiment, the rear end 40a of the discharge port 40 may be located in the range from directly below to in front of the first reference position P1.

[0062] In the above embodiment, a configuration was described in which the outlet 40 has a shape in which its width in the left-right direction increases as it moves from top to bottom. In another embodiment, the outlet 40 may have a shape in which its width in the left-right direction is constant, or a shape in which its width in the left-right direction decreases as it moves from top to bottom.

[0063] (Features of the example) As described above, in one or more embodiments, the chain oil-free chainsaw 2 includes a guide bar 4 whose central axis is aligned along the front-rear direction, a sprocket 26 located behind the guide bar 4 with its axis of rotation aligned along the left-right direction, a saw chain 6 stretched between the guide bar 4 and the sprocket 26, an electric motor 64 for rotating the sprocket 26 around its axis of rotation, a housing 8 for housing the electric motor 64, and a sprocket cover 18 covering the sprocket 26. The saw chain 6 travels in conjunction with the rotation of the sprocket 26, moving from below the guide bar 4 to below the sprocket 26, moving from below the sprocket 26 around the rear of the sprocket 26 to above the sprocket 26, moving from above the sprocket 26 to above the guide bar 4, and moving from above the guide bar 4 around the front of the guide bar 4 to below the guide bar 4. A chain passage 99 through which the saw chain 6 passes is formed by the sprocket 26, the housing 8, and the sprocket cover 18. In the chain passage 99, at least one of the housing 8 and the sprocket cover 18 has an opposing surface 18a that faces the sprocket 26 in the radial direction of the sprocket 26. When the chainsaw 2 is viewed from the side, the straight line passing through the center position of the saw chain 6 (center of the connecting pin 606) at point C1 where the saw chain 6 separates from the guide bar 4 below the guide bar 4, and the straight line passing through the center position of the saw chain 6 (center of the connecting pin 606) at point C2 where the saw chain 6 engages with the sprocket 26 below the sprocket 26, is defined as the first reference straight line L1. The position where the first reference straight line L1 intersects the opposing surface 18a is defined as the first reference position P1, and the inclination angle θ of the opposing surface 18a with respect to the front-rear direction at the first reference position P1 is 90° or more.

[0064] The chips generated by the cutting operation performed by the chainsaw 2 move along the saw chain 6 below the guide bar 4 from front to back. Then, when the saw chain 6 separates from the guide bar 4 and engages with the sprocket 26, the chips fly backward along a trajectory that roughly coincides with the first reference line L1. The chips that fly backward hit the vicinity of the first reference position P1 on the opposing surface 18a. If the chips that hit the opposing surface 18a were to bounce upward, they would proceed to the upper side of the chain passage 99 along with the saw chain 6, and there is a risk that they will become stuck in the chain passage 99. With the above configuration, the inclination angle θ of the opposing surface 18a with respect to the front-rear direction at the first reference position P1 is 90° or more, which suppresses the chips that hit the opposing surface 18a from bouncing upward. This prevents the chips from proceeding to the upper side of the chain passage 99 and becoming stuck in the chain passage 99.

[0065] In one or more embodiments, when the chainsaw 2 is viewed from the side, the inclination angle φ of the opposing surface 18a at the first reference position P1 with respect to the first reference line L1 is 90° or more.

[0066] According to the above configuration, it is possible to more effectively suppress the upward rebound of chips that hit the opposing surface 18a.

[0067] In one or more embodiments, when the chainsaw 2 is viewed from the side, the inclination angle θ of the opposing surface 18a at the first reference position P1 with respect to the front-rear direction is 120° or less.

[0068] If the inclination angle θ of the opposing surface 18a with respect to the front-rear direction at the first reference position P1 exceeds 120°, the size of the housing 8 and sprocket cover 18 will increase in the front-rear direction, and the size of the chainsaw 2 in the front-rear direction will increase. With the above configuration, the size of the housing 8 and sprocket cover 18 can be reduced in the front-rear direction, and the size of the chainsaw 2 in the front-rear direction can be reduced.

[0069] In one or more embodiments, when the chainsaw 2 is viewed from the side, a straight line extending in the front-rear direction passing through the center position of the saw chain 6 (center of the connecting pin 606) at the lowest end of the guide bar 4 is defined as the second reference straight line L2, the position where the second reference straight line L2 intersects the opposing surface 18a is defined as the second reference position P2, and the second reference position P2 is located in the range from directly below to behind the first reference position P1.

[0070] When the saw chain 6 separates from the guide bar 4 and engages with the sprocket 26, the chips that fly backward are affected by gravity and therefore hit not only the first reference position P1 on the opposing surface 18a, but also a certain range below the first reference position P1 on the opposing surface 18a. With the above configuration, the angle of the opposing surface 18a in a certain range where chips are likely to hit can be set so that the chips are less likely to bounce back to the upper side of the chain passage 99.

[0071] In one or more embodiments, when the chainsaw 2 is viewed from the side, the opposing surface 18a between the first reference position P1 and the second reference position P2 does not have a shape that protrudes toward the chain passage 99 side than the straight line connecting the first reference position P1 and the second reference position P2.

[0072] With the above configuration, chips that hit the opposing surface 18a can be easily discharged downwards.

[0073] In one or more embodiments, the housing 8 or sprocket cover 18 is located below the sprocket 26 and includes a discharge port 40 for discharging chips from the chain passage 99, the rear end 40a of the discharge port 40 is located in the range from directly below to rear of the first reference position P1.

[0074] With the above configuration, chips that hit the opposing surface 18a can be easily discharged from the discharge port 40.

[0075] In one or more embodiments, the discharge port 40 has a shape in which its width in the left-right direction increases as it extends from top to bottom.

[0076] According to the above configuration, the efficiency of chip discharge from the discharge port 40 can be improved.

[0077] In one or more embodiments, the sprocket 26 has 9 or more teeth.

[0078] At the point where the saw chain 6 separates from the guide bar 4 and engages with the sprocket 26, a large tension acts on the saw chain 6. If the sprocket 26 has few teeth, the bending angle of the saw chain 6 becomes large at the point where the saw chain 6 separates from the guide bar 4 and engages with the sprocket 26, i.e., at the point where a large tension acts on the saw chain 6, and the connection point between the drive link 602 and the connecting pin 606 of the saw chain 6 becomes prone to wear. With the above configuration, since the sprocket 26 has nine or more teeth, the bending angle of the saw chain 6 can be reduced at the point where the saw chain 6 separates from the guide bar 4 and engages with the sprocket 26, i.e., at the point where a large tension acts on the saw chain 6, and wear on the connection point between the drive link 602 and the connecting pin 606 of the saw chain 6 can be suppressed.

[0079] In one or more embodiments, the guide bar 4 is a guide bar 4 in which a sprocket is not incorporated into the tip portion.

[0080] In a guide bar with a sprocket incorporated at its tip, when the connection point between the drive link 602 and the connecting pin 606 of the saw chain 6 wears down and the saw chain 6 stretches, the engagement between the sprocket at the tip of the guide bar and the drive link 602 becomes poor, making it prone to generating abnormal noise. With the above configuration, by using a guide bar 4 that does not have a sprocket incorporated at its tip, it is possible to suppress the generation of abnormal noise even when the connection point between the drive link 602 and the connecting pin 606 of the saw chain 6 wears down and the saw chain 6 stretches.

[0081] In one or more embodiments, the speed at which the saw chain 6 travels is 9 m / s or less.

[0082] The faster the saw chain 6 travels, the more easily it wears down. With the above configuration, wear on the saw chain 6 can be suppressed by keeping its travel speed below 9 m / s. [Explanation of Symbols]

[0083] 2: Chainsaw 4: Guide bar 4a: Notch 6: Saw chain 8: Housing 10: Chain cover 10a: Rotating shaft 12: Gear Housing 14: Motor Housing 16: Grip 17: Battery pack mounting section 18: Sprocket cover 18a: Opposite surface 20: Handguard 26: Sprocket 28: Pin 32: Bolt 36: Sprocket cover body 38: Through hole 40: Outlet 40a: Rear end of the outlet 40b: Front end of the outlet 42:Locking member 44: Locking member body 46: Nut 48: Nail area 50: Trigger lever 60: Control Unit 64: Electric motor 72:Reducer 72a: First bevel gear 72b: Second bevel gear 74: Coil 76: Status 78: Rotor 80: Motor shaft 82: Cooling fan 84: Drive shaft 86: Bearings 99: Chain aisle 140: Exhaust port 142: Air intake 602: Drive Link 604: Sidelink 606: Connecting pin 608: Cutting section 610: Tie Strap B: Battery pack C1: Detachment point C2: Engagement point L1: 1st reference straight line L2: Second reference straight line P1: 1st reference position P2: 2nd reference position RX: Rotation axis θ: Inclination angle of the opposing surface with respect to the front-to-back direction at the first reference position. φ: Inclination angle of the opposing surface with respect to the first reference line at the first reference position ψ: Inclination angle of the opposing surface with respect to the front-to-back direction at the second reference position.

Claims

1. This is a chain oil-free type chainsaw. A guide bar positioned so that its central axis aligns with the front-to-back direction, A sprocket positioned behind the aforementioned guide bar, with its axis of rotation aligned in the left-right direction, The saw chain stretched over the guide bar and the sprocket, An electric motor that rotates the sprocket around the rotation shaft, A housing for the electric motor, The system includes a sprocket cover that covers the sprocket, The saw chain moves as the sprocket rotates, moving from below the guide bar to below the sprocket, moving from below the sprocket to above the sprocket by going around the rear of the sprocket, moving from above the sprocket to above the guide bar, and moving from above the guide bar to below the guide bar by going around the front of the guide bar. The sprocket, the housing, and the sprocket cover form a chain passage through which the saw chain passes. In the chain passage, at least one of the housing and the sprocket cover has an opposing surface that faces the sprocket in the radial direction of the sprocket, A chainsaw in which, when viewed from the side, the center position of the saw chain at the point where the saw chain separates from the guide bar below the guide bar and the center position of the saw chain at the point where the saw chain engages with the sprocket below the sprocket are defined as the first reference line, the position where the first reference line intersects the opposing surface is defined as the first reference position, and the inclination angle of the opposing surface with respect to the front-rear direction at the first reference position is 90° or more.

2. The chainsaw according to claim 1, wherein, when the chainsaw is viewed from the side, the angle of inclination of the opposing surface at the first reference position with respect to the first reference line is 90° or more.

3. The chainsaw according to claim 1 or 2, wherein, when the chainsaw is viewed from the side, the inclination angle of the opposing surface at the first reference position with respect to the front-rear direction is 120° or less.

4. The chainsaw according to any one of claims 1 to 3, wherein, when the chainsaw is viewed from the side, a straight line extending in the front-rear direction passing through the center position of the saw chain at the lowest end of the guide bar is defined as the second reference line, the position where the second reference line intersects the opposing surface is defined as the second reference position, and the second reference position is located in the range from directly below to the rear of the first reference position.

5. The chainsaw according to claim 4, wherein, when viewed from the side, the opposing surface between the first reference position and the second reference position does not have a shape that protrudes toward the chain passage side than the straight line connecting the first reference position and the second reference position.

6. The housing or the sprocket cover is positioned below the sprocket and is equipped with an outlet for discharging chips from the chain passage. The chainsaw according to any one of claims 1 to 5, wherein the rear end of the discharge port is located in the range from directly below to the rear of the first reference position.

7. The chainsaw according to claim 6, wherein the discharge port has a shape in which the width in the left-right direction increases as it goes from the top to the bottom.

8. The chainsaw according to any one of claims 1 to 7, wherein the number of teeth on the sprocket is nine or more.

9. The chainsaw according to any one of claims 1 to 8, wherein the guide bar is a guide bar in which a sprocket is not incorporated at the tip.

10. A chainsaw according to any one of claims 1 to 9, wherein the speed at which the saw chain travels is 9 m / s or less.

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