Work equipment

Abstract

To provide a work machine improved in convenience.SOLUTION: A hedge trimmer 1 that is a work machine comprises: an eccentric cam 602 that rotates by receiving driving force of a driving shaft 40 provided in an electric motor 4; an upper blade 301 and a lower blade 302 which reciprocate by rotation of the eccentric cam 602; a support part 7 that rotatably supports the eccentric cam 602; a fan 5 that rotates by receiving driving force of the driving shaft 40; and a housing 2. The support part 7 has a base portion 700, and a support shaft 701 extending from the base portion 700 toward one side in a first direction to support the eccentric cam 602. The housing 2 has an air intake port 211, an air exhaust port, and an air passage through which airstream flows from the air intake port 211 to the air exhaust port so as to flow in the vicinity of the electric motor 4. The air passage includes an upstream-side passage positioned upstream of the electric motor 4 and a downstream-side passage positioned downstream of the electric motor 4. The support shaft 701 is provided to be able to exchange heat with the upstream-side passage.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a working machine.

Background Art

[0002] Conventionally, a hedge trimmer having an upper blade and a lower blade that reciprocate in the front-rear direction as tip tools and used for pruning trees, shaping hedges, etc. is known. Patent Document 1 discloses a hedge trimmer having an eccentric cam in which the upper blade and the lower blade are engaged, and a shaft that serves as a rotation axis of the eccentric cam. In the hedge trimmer of Patent Document 1, the camshaft is fixed to a bearing holder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the hedge trimmer of Patent Document 1, the rib of the housing abuts against the upper surface of the bearing holder and covers the upper surface of the bearing holder. Therefore, there is a possibility that the shaft generates heat as the eccentric cam rotates. If the output is suppressed to suppress the rotation of the eccentric cam in order to suppress such heat generation, the convenience during work using the hedge trimmer is impaired.

Means for Solving the Problems

[0005] A work machine according to the first embodiment includes a motor having a drive shaft, an eccentric cam that rotates in response to the driving force of the drive shaft, a tip tool that reciprocates by the rotation of the eccentric cam, a support portion that rotatably supports the eccentric cam, a fan that rotates in response to the driving force of the drive shaft, and a housing that supports the motor, the eccentric cam, the support portion, and the fan. The support portion has a base and a support shaft that extends from the base toward one side in a first direction and supports the eccentric cam. The housing has an intake port, an exhaust port, and an air passage through which air flows from the intake port to the exhaust port by the fan so as to flow around the motor. The air passage includes an upstream passage located upstream of the motor and a downstream passage located downstream of the motor. The support shaft is provided so as to be able to exchange heat with the upstream passage. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a work machine with improved convenience. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram shows the structure of the implement according to the embodiment. [Figure 2] This is a cross-sectional view of the work machine along line AA in Figure 1. [Figure 3] Figure 1 is a cross-sectional view of the work machine along the BB line. [Figure 4] This is a perspective view of the housing's exterior. [Figure 5] This is an external view illustrating the structure of the support section. [Figure 6] This is a diagram illustrating the air passages within the housing. [Figure 7] This is a diagram illustrating the air passages within the housing. [Figure 8] This diagram shows the structure of the work implement in a modified example. [Modes for carrying out the invention]

[0008] The implement of this embodiment will be described with reference to the drawings. In this embodiment, a hedge trimmer will be used as an example of an implement.

[0009] Figure 1 is a longitudinal cross-sectional view showing the overall structure of the hedge trimmer 1 according to the embodiment. Figure 2 is a cross-sectional view of the hedge trimmer 1 along line AA in Figure 1. Figure 3 is a cross-sectional view of the hedge trimmer 1 along line BB in Figure 1.

[0010] In the following explanation, the upper part of Figures 1 and 2 may be referred to as "up" and the lower part as "down." Also, the right side of Figure 1 may be referred to as "front" and the left side as "back." Similarly, the left side of Figure 2 may be referred to as "left" and the right side as "right." Furthermore, the vertical direction may be referred to as the first direction, the front-back direction perpendicular to the first direction as the second direction, and the left-right direction perpendicular to both the first and second directions as the third direction. Additionally, the downside may be referred to as one side of the first direction, and the upside as the other side of the first direction.

[0011] The hedge trimmer 1 comprises a housing 2, a blade assembly 3 protruding forward from the front of the housing 2, an electric motor 4, a fan 5, a power transmission mechanism 6, and a support part 7.

[0012] <Housing 2> The housing 2 is formed in a left-right split manner by integral molding of a resin such as plastic. The housing 2 has a main body portion 21 and a first handle portion 22. The first handle portion 22 has a gripping portion 221 and a connecting portion 222. The gripping portion 221 is provided at the rear of the main body portion 21 and extends rearward along the front-rear direction. The gripping portion 221 is gripped by the operator during work. The connecting portion 222 is provided at the rear of the main body portion 21 and extends rearward along the front-rear direction below the gripping portion 221.

[0013] A trigger 100 is provided at the front end of the gripping portion 221, that is, near the main body portion 21. The trigger 100 protrudes downward from the gripping portion 221 while being biased by a spring or the like. A mounting portion is provided at the rear of the gripping portion 221, and the battery pack 101 is detachably attached thereto.

[0014] The main body 21 houses an electric motor 4, a fan 5, a power transmission mechanism 6, and a support section 7. The structure of the main body 21 will be described in detail later. A second handle section 230 and a protector 231 are provided at the front of the main body 21. The operator uses the hedge trimmer 1 by gripping the gripping section 221 of the first handle section 22 with one hand and the second handle section 230 with the other hand. The protector 231 is made of, for example, transparent synthetic resin and is provided in front of the second handle section 230. Therefore, the protector 231 protects the operator's hand gripping the second handle section 230 from branches and leaves cut by the hedge trimmer 1.

[0015] <Main body 21> The main body 21 will be described using the external perspective view of the housing 2 shown in Figure 4. Note that Figure 4 shows one side (left side) of the housing 2, which is formed to be separable into left and right sections. The other side (right side) of the housing 2 has a symmetrical shape with respect to the center line of the left side. Therefore, the following explanation will mainly focus on the structure of the left side of the housing 2, but the explanation given for the left side of the housing 2 will also apply to the right side.

[0016] Two side surfaces 210a and 210b (collectively referred to as side surface 210) are formed on the front side of the main body 21 of the housing 2 in the left-right direction (third direction) (see Figure 2). The two side surfaces 210 are inclined surfaces that are tilted with respect to the vertical direction. Specifically, side surface 210a is an inclined surface that protrudes more to the left as it goes downwards, and side surface 210b is an inclined surface that protrudes more to the right as it goes downwards. In other words, the two side surfaces 210a and 210b are inclined surfaces that are spaced apart from each other in the left-right direction (third direction) on one side (downward side) in the vertical direction (first direction).

[0017] The main body portion 21 is formed with an intake port 211, an exhaust port 212, a partition wall 213, and an abutting rib 214. The intake port 211 is a slit-shaped opening extending in the front-rear direction formed on each of the two side surfaces 210 in the left-right direction (the third direction). When a fan 5 described later is driven, air for cooling the support portion 7, the electric motor 4, etc. described later flows in from the outside through the intake port 211.

[0018] The exhaust port 212 is a slit-shaped opening extending in the front-rear direction formed on the rear and upper sides with respect to the intake port 211. The air that has flowed into the interior of the housing 2 through the intake port 211 described above flows out to the outside through the exhaust port 212.

[0019] The partition wall 213 is provided between the intake port 211 and the exhaust port 212 in the front-rear direction and is formed in a plate shape extending in the up-down direction. The electric motor 4 and the fan 5 described later are arranged on the rear side with respect to the partition wall 213. The lower end portion of the partition wall 213 is located below the intake port 211. A window portion 215 is formed near the central portion at the lower end portion of the partition wall 213. That is, the window portion 215 is arranged between the two side surfaces 210 in the left-right direction (the third direction), for example, near the central portion in the left-right direction. The window portion 215 is a through-hole penetrating the partition wall 213 in the front-rear direction (the second direction). The air that has flowed in from the intake port 211 described above passes through the window portion 215 and flows to the rear side of the partition wall 213.

[0020] The abutting rib 214 is connected to the lower end portion of the partition wall 213 and is formed in a plate shape extending forward. For this reason, the abutting rib 214 is formed below the intake port 211. The electric motor 4 and the fan 5 are arranged on the upper side with respect to the abutting rib 214, and the power transmission mechanism 6 and the support portion 7 described later are arranged on the lower side. Incidentally, as described above, since the housing 2 is formed by integral molding of resin, the abutting rib 214 is also made of resin.

[0021] The contact rib 214 has a first through hole 216 and a second through hole 217. The first through hole 216 is formed on the front side relative to the partition wall 213 and penetrates the contact rib 214 in the vertical direction. Specifically, the first through hole 216 is formed in the front-to-back direction (second direction) at a position that coincides with the position where the air intake port 211 is formed. The first through hole 216 is formed between the two side surfaces 210 in the left-to-right direction (third direction). More specifically, the first through hole 216 is formed near the center of the contact rib 214 in the left-to-right direction. The support shaft 701 of the support part 7, which will be described later, is positioned in the first through hole 216.

[0022] The second through-hole 217 is formed on the rear side of the partition wall 213 and penetrates the abutment rib 214 in the vertical direction. Specifically, the second through-hole 217 is formed below the electric motor 4, which will be described later. A pinion 600, provided on the drive shaft 40 of the electric motor 4, which will be described later, is inserted through the second through-hole 217.

[0023] <Electric Motor 4> An example of a motor, the electric motor 4, is housed within the main body 21 and supported by the housing 2. Specifically, the electric motor 4 is positioned behind the partition wall 213 and above the contact rib 214. The electric motor 4 is a casing motor having, for example, a rotor 41, a stator 42, and carbon brushes 43. A drive shaft 40 is fixed to the rotor 41. The drive shaft 40 is oriented axially in the vertical direction (first direction). A pinion 600, which is part of the power transmission mechanism 6 described later, is provided at the lower tip of the drive shaft 40. The electric motor 4 rotates when it receives power from the battery pack 101 in response to the operator's operation of the trigger 100. The drive shaft 40 also rotates in accordance with the rotation of the electric motor 4. The pinion 600 also rotates due to the rotation of the drive shaft 40. The electric motor 4 may also be a brushless motor.

[0024] <Fan 5> The fan 5 is mounted on the drive shaft 40 so as to be positioned above the rotor 41 and is supported by the housing 2. The fan 5 has multiple blades and rotates when the electric motor 4 rotates, receiving the driving force from the drive shaft 40. As the fan 5 rotates, air from outside the hedge trimmer 1 flows into the housing 2 through the air intake port 211 of the housing 2.

[0025] <Blade Assembly 3> The blade assembly 3 comprises a pair of blades, namely an upper blade 301 and a lower blade 302, which are the tip tools, a blade holder 303, and a guide bar 304. The blade holder 303 and the guide bar 304 are fixed together by a number of bolts and nuts. The blade holder 303 is fixed to the housing 2 at the rear by bolts 305 and 306. This fixes the blade assembly 3 to the housing 2.

[0026] The upper blade 301 and the lower blade 302 are positioned so as to overlap each other in the vertical direction. When the driving force of the electric motor 4 is transmitted to the upper blade 301 and the lower blade 302 via the power transmission mechanism 6 described later, they move linearly back and forth in the front-rear direction in opposite phases. That is, when the upper blade 301 moves forward in the direction away from the housing 2 (forward), the lower blade 302 moves backward in the direction closer to the housing 2 (rearward). Also, when the upper blade 301 moves backward in the direction closer to the housing 2, the lower blade 302 moves forward in the direction away from the housing 2.

[0027] <Power transmission mechanism 6> The power transmission mechanism 6 is positioned below the contact rib 214. The power transmission mechanism 6 includes a pinion 600, a gear 601, and an eccentric cam 602. The pinion 600 extends vertically and, as described above, is located at the lower end of the drive shaft 40. The gear 601 is rotatably mounted around the support shaft 701 of the support part 7, which will be described later, as its axis of rotation. The gear 601 is a gear with teeth formed along its outer circumference and meshes with the pinion 600. Therefore, when the drive shaft 40 rotates due to the rotation of the electric motor 4, the gear 601, which meshes with the pinion 600, rotates around the support shaft 701 as its center of rotation in accordance with the rotation of the drive shaft 40.

[0028] The eccentric cam 602 is supported in the housing 2 and is rotatable integrally with the gear 601, with the support shaft 701 as the center of rotation. Therefore, when the eccentric cam 602 receives the driving force from the drive shaft 40 in accordance with the rotation of the electric motor 4, it rotates together with the gear 601. The eccentric cam 602 has a first eccentric portion 602a and a second eccentric portion 602b. The first eccentric portion 602a is provided on the upper side of the eccentric cam 602 and is formed in the shape of a disc with its center point at a predetermined distance from the support shaft 701, which is the center of rotation. The second eccentric portion 602b is provided on the lower side of the eccentric cam 602 and is formed in the shape of a disc with its center point at a predetermined distance from the support shaft 701. The center points of the first eccentric portion 602a and the second eccentric portion 602b are positioned 180° apart with respect to the support shaft 701, which is the center of rotation. Therefore, when the eccentric cam 602 rotates, the first eccentric portion 602a and the second eccentric portion 602b are in a positional relationship where their rotational phases are 180° apart.

[0029] The upper blade 301 and lower blade 302 described above are connected to the eccentric cam 602. Specifically, the upper blade 301 is positioned to engage with the first eccentric portion 602a, and the lower blade 302 is positioned to engage with the second eccentric portion 602b. Therefore, when the eccentric cam 602 rotates, the reciprocating motion of the upper blade 301 and the reciprocating motion of the lower blade 302, which are engaged with the first eccentric portion 602a and the second eccentric portion 602b, have a phase difference of 180°, resulting in a phase difference of 180°.

[0030] <Support part 7> The support portion 7 is positioned below the contact rib 214 and is supported by the housing 2. The support portion 7 rotatably supports the eccentric cam 602 described above. The support portion 7 has a base portion 700 and a support shaft 701.

[0031] Figure 5 is a perspective view illustrating the structure of the support portion 7, where Figure 5(A) is an external perspective view of the base portion 700, and Figure 5(B) is a perspective view of the housing 2 and the support portion 7 attached to the housing 2. The base portion 700 is formed in a plate shape having a surface perpendicular to the vertical direction. As shown in Figures 1 and 5(B), the upper surface of the base portion 700 (the other side in the first direction) abuts against the lower surface of the abutment rib 214 (one side in the first direction).

[0032] The base portion 700 has a first opening 702 and a second opening 703. The first opening 702 and the second opening 703 are openings that penetrate the base portion 700 in the vertical direction. The first opening 702 is formed so that when the support portion 7 is placed in the housing 2, it is located below the first through hole 216 formed in the contact rib 214. The support shaft 701, which will be described later, is fitted into the first opening 702, for example by press-fitting.

[0033] The second opening 703 is formed so as to be located below the second through hole 217 formed in the contact rib 214 when the support portion 7 is placed in the housing 2. The pinion 600 of the power transmission mechanism 6 described above is inserted into the second opening 703. The pinion 600 is rotatably supported via a bearing or the like.

[0034] As described above, the first through-hole 216 is formed on the front side of the partition wall 213, and the second through-hole 217 is formed on the rear side of the partition wall 213. Therefore, the first opening 702 and the second opening 703 are located at different positions in the front-rear direction (second direction). As described above, the first opening 702 and the second opening 703 are formed at different positions in the front-rear direction on the base 700, with the support shaft 701 located in the first opening 702 and the pinion 600 located in the second opening 703. The pinion 600 and the fan 5 are each located on the drive shaft 40 which extends in the vertical direction. Therefore, the support shaft 701 and the fan 5 are located at different positions in the front-rear direction (second direction). Alternatively, it can be said that the support shaft 701 and the fan 5 are separated by the partition wall 213 in the front-rear direction (second direction).

[0035] Furthermore, the first opening 702 is located below the first through-hole 216 of the contact rib 214, and in the left-right direction, the first through-hole 216 is formed between the two side surfaces 210. Thus, it can be said that the support shaft 701 is positioned between the two side surfaces 210 in the left-right direction (third direction).

[0036] The support shaft 701 is made of metal and is formed in the shape of a rod extending in the vertical direction. The upper end of the support shaft 701 is fitted into and fixed in the first opening 702 formed in the base 700. Therefore, the support shaft 701 extends downward (to one side in the first direction) from the base 700 and does not perform rotational drive. Since the contact rib 214 is provided below the intake port 211 and the support portion 7 is positioned below the contact rib 214, it can be said that the support shaft 701 is positioned below the intake port 211 (to one side in the first direction). Below the support shaft 701, as described above, the eccentric cam 602 is rotatably provided. That is, it can be said that the support shaft 701 rotatably supports the eccentric cam 602. In other words, the eccentric cam 602 is rotatable relative to the support shaft 701.

[0037] <Hedge trimmer 1 operation> When the operator operates the trigger 100, which protrudes downward from the gripping section 221, the trigger switch is turned on. When the trigger switch is turned on, power is supplied from the battery pack 101 to the electric motor 4. This causes the electric motor 4 to rotate, and the driving force is transmitted to the blade assembly 3 via the drive shaft 40 and the power transmission mechanism 6. As a result, the upper blade 301 and the lower blade 302 reciprocate along the front-rear direction.

[0038] Furthermore, the fan 5 rotates in response to the driving force of the drive shaft 40, which is rotated by the rotational drive of the electric motor 4. As the fan 5 rotates, air flows from the outside into the housing 2 through the intake port 211. The airflow inside the housing 2 will be described below.

[0039] <Airflow inside housing 2> Figures 6 and 7 show the airflow paths (air passages) within housing 2. Figure 6(A) is an enlarged view of region C enclosed by the dashed line in Figure 2, Figure 6(B) is an enlarged view of region D enclosed by the dashed line in Figure 3, and Figure 7 is an enlarged view of region E enclosed by the dashed line in Figure 5(B).

[0040] When fan 5 rotates, air flows into housing 2 from intake port 211 along arrow AR0 shown in Figure 6(A). As described above, the two sides 210 are inclined surfaces, and sides 210a and 210b are closer to each other in the left-right direction as they are higher up and further apart as they are lower down. Therefore, if the thickness of side 210 is uniform, the inner wall end 211c of the upper wall surface 211a of intake port 211 is located inside housing 2 than the inner wall end 211d of the lower wall surface 211b. Consequently, the air that has passed through intake port 211 is restricted from flowing upward by the end 211c and flows downward as shown by arrow AR1.

[0041] Air flowing into the housing 2 does not flow below the contact rib 214 inside the housing 2 because the contact rib 214 is in contact with the upper surface of the base 700 included in the support portion 7. Also, at the lower end of the partition wall 213, a window portion 215 is formed near the center in the left-right direction, penetrating the partition wall 213. Therefore, air flowing in from the left and right sides 210 collects below the center inside the housing 2, as shown by arrow AR2 in Figures 6(A) and (B), and flows towards the rear. The air then passes through the window portion 215 and flows towards the rear of the partition wall 213, that is, towards the bottom of the electric motor 4. After that, as shown by arrow AR3 in Figure 7, the air flows upward. Although not shown in Figure 7, as shown in Figure 1, the electric motor 4 is housed inside the housing 2, so the air flows along arrow AR3 through gaps provided around the electric motor 4, such as between the rotor 41 and the stator 42. The air then passes through the fan 5 (which is not shown in Figure 7) and flows left and right along the arrow AR4, exiting to the outside of the housing 2 through the exhaust port 212.

[0042] As the airflow described above is formed, the fan 5 creates an air passage 250 in the housing 2 through which air flows from the intake port 211 to the exhaust port 212 along the arrows AR1, AR2, and AR3. Of this air passage 250, the passage located upstream of the electric motor 4, i.e., on the intake port 211 side indicated by arrows AR1 and AR2, is called the upstream passage 251, and the passage located downstream of the electric motor 4, i.e., on the exhaust port 212 side indicated by arrow AR3, is called the downstream passage 252. The air flowing through this air passage 250 cools each component inside the housing 2.

[0043] <Cooling within Housing 2> As described above, the support shaft 701 of the support section 7 is the rotation axis of the gear 601 and the eccentric cam 602, but the support shaft 701 itself does not rotate because it is fixed to the base 700. This support shaft 701 generates heat due to the rotation of the gear 601 and the eccentric cam 602. The heated support shaft 701 is cooled by the air flowing through the upstream passage 251 of the air passage 250. In other words, the support shaft 701 is provided so as to be able to exchange heat with the upstream passage 251. More specifically, the support shaft 701 is provided so as to be able to exchange heat with the air flowing through the upstream passage 251.

[0044] Specifically, as described above, the upper part of the support shaft 701 is fitted into the first opening 702 of the base 700, which is located below the first through hole 216 of the contact rib 214. In other words, in a vertical view, the support shaft 701 is positioned within the area enclosed by the wall surface of the first through hole 216. Since the first through hole 216 formed in the contact rib 214 penetrates the contact rib 214 in the vertical direction, it can also be said that the first through hole 216 connects the support shaft 701 to the upstream passage 251. That is, the support shaft 701 is exposed to the upstream passage 251. More specifically, since the contact rib 214 abuts against the upper surface of the base 700 and separates the upstream passage 251 from the support part 7, only the upper part of the support shaft 701 is exposed to the upstream passage 251.

[0045] In particular, the first through-hole 216 of the contact rib 214 is formed in a position that coincides with the position where the intake port 211 is formed in the front-rear direction, as described above. In other words, the support shaft 701 is positioned in a position that coincides with the position where the intake port 211 is formed in the front-rear direction (second direction). Because the upper part of the support shaft 701 is exposed to the upstream passage 251 near the intake port 211, the upper part of the support shaft 701 is cooled by the incoming, unheated air as shown by arrow AR1. Furthermore, because the support shaft 701 is made of metal and has excellent thermal conductivity, it is possible to cool the lower part of the support shaft 701 that extends along the vertical direction. In addition, by cooling the support shaft 701, it is possible to cool the power transmission mechanism 6, including the eccentric cam 602 supported by the support shaft 701.

[0046] Furthermore, the electric motor 4, which is driven by power supplied from the battery pack 101, is cooled by air flowing along the arrow AR3 in the downstream passage 252.

[0047] According to the embodiments described above, at least one of the following effects can be obtained.

[0048] (1) The hedge trimmer 1 comprises an electric motor 4, an eccentric cam 602, an upper blade 301 and a lower blade 302 which are tip tools, a support part 7, a fan 5, and a housing 2. The support part 7 has a base 700 and a support shaft 701 that extends from the base 700 toward one side (downward) in a first direction and supports the eccentric cam 602. The housing 2 has an intake port 211, an exhaust port 212, and an air passage 250 through which air flows from the intake port 211 to the exhaust port 212 by the fan 5 so as to flow around the electric motor 4. The air passage 250 includes an upstream passage 251 located upstream of the electric motor 4 and a downstream passage 252 located downstream of the electric motor 4, and the support shaft 701 is provided so as to be able to exchange heat with the upstream passage 251. As a result, the support shaft 701 can be cooled by the air flowing through the upstream passage 251, thereby suppressing the heat generated by the support shaft 701 due to the rotation of the eccentric cam 602. Therefore, there is no need to suppress the output of the electric motor 4 and limit the rotation of the eccentric cam 602 in order to prevent the support shaft 701 from becoming too hot due to heat generation, which contributes to improved convenience when working with the hedge trimmer 1.

[0049] (2) The support shaft 701 is exposed to the upstream passage 251. As a result, the support shaft 701 is cooled by the unheated air flowing in from the intake port 211, thus achieving high cooling efficiency.

[0050] (3) The air intake port 211 is positioned so that its position in the second direction (front-to-back direction) coincides with the support shaft 701, and is located on the two sides 210 of the housing 2 in the third direction (left-to-right direction). The window portion 215 formed in the support shaft 701 and the partition wall 213 is located between the two sides 210 in the third direction (left-to-right direction). As a result, the air flowing in from the two sides 210a and 210b, which are located at different positions in the left-to-right direction, will gather near the support shaft 701, increasing the amount of air flowing near the support shaft 701 and enabling efficient cooling of the support shaft 701.

[0051] (4) The support shaft 701 is positioned on one side (downward) of the intake port 211 in the first direction, and the two side surfaces 210 are inclined surfaces that are spaced apart from each other in the third direction (left-right direction) on one side (downward) in the first direction. As a result, as described above, the end 211c of the upper wall surface 211a of the intake port 211 is located inside the housing 2 than the end 211d of the lower wall surface 211b. Therefore, the air that has passed through the intake port 211 is restricted from flowing upward by the end 211c and flows downward as shown by arrow AR1. As a result, the air flows towards the support shaft 701 which is located below the intake port 211, so that the support shaft 701 can be cooled efficiently.

[0052] (5) The contact rib 214 that abuts against the other side (upper side) of the base 700 in the first direction and separates the upstream passage 251 from the support portion 7 has a first through hole 216 that penetrates in the first direction (vertical direction) and connects the support shaft 701 and the upstream passage 251. As a result the support shaft 701 is exposed to the upstream passage 251, and the upper part of the support shaft 701 is cooled by the air.

[0053] (6) The support shaft 701 is positioned within the area enclosed by the wall surface of the first through hole 216 in the first direction view (up and down view). This allows the upper part of the support shaft 701 to be exposed to the upstream passage 251, thereby enabling the support shaft 701 to be cooled.

[0054] (7) The eccentric cam 602 is rotatable relative to the support shaft 701, the support shaft 701 is made of metal, and the contact rib 214 is made of resin. Therefore, the support shaft 701, which has higher heat transfer characteristics than the contact rib 214, can be cooled by the airflow through the air passage 250.

[0055] The above-described embodiment can be modified as follows.

[0056] <Variation> Figure 8 is a longitudinal cross-sectional view showing the overall structure of the modified hedge trimmer 1. In the following description, the same reference numerals are used for components identical to those in the embodiment of the hedge trimmer 1, and their descriptions are omitted. The modified hedge trimmer 1 has a heat sink 300 as a heat dissipation / heat transfer part, formed from a metal such as aluminum, iron, or copper, which has high heat transfer properties. The heat sink 300 is provided in the first through hole 216 of the contact rib 214. The lower surface of the heat sink 300 is in contact with the upper surface of the support shaft 701, which is fitted into the first opening 702 of the support part 7 located below the contact rib 214. Therefore, air flowing in through the air intake 211 can cool the support shaft 701 via the heat sink 300, making it possible to obtain the same effects as those obtained in the embodiment described above.

[0057] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention. For example, the fan 5 may be positioned below the rotor 41, and exhaust ports may be added to the left and right sides of the fan 5. In this case, a restricting wall is provided to prevent the air discharged by the fan 5 from flowing back into the intake port 211, and an air passage is created in which air flows from the intake port 211 along arrows AR1 and AR2, cooling the support shaft 701 while heading towards the fan 5, and an air passage is created which flows from the exhaust port 212 in the opposite direction to arrows AR4 and AR3, cooling the electric motor 4 while heading towards the fan 5. This provides the same effects as the embodiments and modifications described above. [Explanation of symbols]

[0058] 1 Hedge trimmer, 2 Housing, 3 Blade assembly, 4 Electric motor, 5 Fan, 6 Power transmission mechanism, 7 Support part, 21 Main body, 22 First handle part, 40 Drive shaft, 100 Trigger, 101 Battery pack, 210, 210a, 210b Side, 211 Air intake, 211a Upper wall, 211b Lower wall, 211c, 211d End, 212 Exhaust port, 213 Partition wall, 214 Contact rib, 215 Window, 216 First through hole, 217 Second through hole, 221 Gripping part, 222 Connection part, 250 Air passage, 251 Upstream passage, 252 Downstream passage, 300 Heat sink, 301 Upper blade, 302 Lower blade, 600 Pinion, 601 Gear, 602 Eccentric cam, 602a First eccentric part, 602b Second eccentric part, 700 Base, 701 Support shaft, 702 First opening, 703 Second opening

Claims

1. A motor having a drive shaft, An eccentric cam that rotates by receiving the driving force of the aforementioned drive shaft, The tip tool reciprocates due to the rotation of the eccentric cam, A support portion that rotatably supports the eccentric cam, A fan that rotates by receiving the driving force of the aforementioned drive shaft, The device comprises the motor, the eccentric cam, the support portion, and the fan, and a housing that supports the fan. The support portion comprises a base and a support shaft extending from the base toward one side in the first direction and supporting the eccentric cam. The housing has an intake port, an exhaust port, and an air passage through which air flows from the intake port to the exhaust port by the fan so as to flow around the motor. The air passage includes an upstream passage located upstream of the motor and a downstream passage located downstream of the motor. The support shaft is provided so as to be able to exchange heat with the upstream passage, and is part of the work machine.

2. In the work machine described in claim 1, The aforementioned support shaft is exposed to the upstream passage of the work machine.

3. In the work machine described in claim 2, The support shaft and the fan are positioned at different locations in a second direction perpendicular to the first direction. The housing has a partition wall separating the support shaft and the fan in the second direction, and a window portion penetrating the partition wall in the second direction. The intake port is positioned such that its position in the second direction coincides with the support shaft, and is positioned on two sides of the housing in a third direction perpendicular to the first and second directions. The support shaft and the window portion are positioned between the two sides in the third direction, in the work machine.

4. In the work machine described in claim 3, The support shaft is positioned on one side of the intake port in the first direction, A work machine in which the two aforementioned sides are inclined surfaces that are spaced apart from each other in the third direction on one side in the first direction.

5. In the work machine described in claim 2, The housing has a contact rib that abuts against the other side surface of the base in the first direction, separating the upstream passage from the support portion. The abutment rib has a through hole that penetrates in the first direction and connects the support shaft and the upstream passage, in a work machine.

6. In the work machine described in claim 5, The support shaft is positioned within the area enclosed by the wall surface of the through-hole in the first viewing direction of the work machine.

7. In the work machine described in claim 5, The eccentric cam is rotatable relative to the support shaft, The support shaft is made of metal. The aforementioned contact rib is made of resin, in the work machine.

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