WO2016140085A1

WO2016140085A1 - Motorized work implement

Info

Publication number: WO2016140085A1
Application number: PCT/JP2016/054906
Authority: WO
Inventors: 大塚　和弘; 健太郎金谷; 大輔百鳥
Original assignee: 日立工機株式会社
Priority date: 2015-03-03
Filing date: 2016-02-19
Publication date: 2016-09-09

Abstract

Provided is a hedge trimmer capable of pruning foliage in a manner that will avoid discoloration and drying of foliage caused by heat damage from cooling air but will not decrease work efficiency. The hedge trimmer is provided with: an engine 20 as a power source; a cooling fan 18 disposed on the upper end side of a crankshaft 24 of the engine 20; and a work tool 6 mounted to and extending forward from a power conversion unit 5 disposed on the lower end side of the crankshaft 24. The hedge trimmer is configured such that cooling air 8 generated by the cooling fan 18 cools the engine 20 and flows towards the other end side of the crankshaft 24. The hedge trimmer is provided with an air guide member 10 for guiding the cooling air 8 that has passed the engine 20 to the front.

Description

Engine working machine

The present invention relates to a portable engine work machine, and more particularly to an engine work machine in which a work target is located on a bottom surface of a main body.

Engines are widely used as power sources in portable work machines such as hedge trimmers. In the hedge trimmer, as shown in the cited document 1, a structure is adopted in which high-temperature cooling air after cooling the engine is concentrated and discharged toward the bottom surface of the main body, which is hard to hit the operator's body. On the other hand, when pruning a plant with a hedge trimmer, it is basically performed with the bottom side of the work machine facing the plant. Therefore, when pruning is performed with the hedge trimmer having the above-mentioned general structure, the plant is long. Discoloration or withering of leaves may occur when exposed to high-temperature cooling air. For this reason, in order to protect the plant, it was necessary to perform the pruning operation with care so that the contact time between the working machine and the plant is shortened so that the cooling air does not hit for a long time.

JP 2013-227918 A

However, in order to perform the operations as described above, it is necessary to frequently move the position of the working machine during pruning, or to temporarily remove the working machine from the planted trees, which causes a problem of poor work efficiency. In addition, there are means such as watering the plant in advance in order to increase the contact time with the plant, but there are problems that the number of work man-hours is increased and that it cannot be performed in a place without water.

The present invention has been made in view of the above background, and an object thereof is to provide a hedge trimmer that can efficiently perform a pruning operation without worrying about the contact time between a plant and a working machine during pruning. It is in.

An engine as a power source, a cooling fan provided above the engine, and a work tool attached to a power conversion unit provided below the engine and extending forward, are generated by the cooling fan. An engine working machine configured to cool the engine and flow downward is provided with an air guide member that guides the cooling air that has passed through the engine forward.

According to the present invention, by controlling the discharge direction and discharge amount of the cooling air, the heat damage to the plant by the cooling air is reduced, so the pruning work without worrying about the contact time between the plant and the working machine Work efficiency is improved.

Overall perspective view of hedge trimmer according to an embodiment of the present invention Left side view of a hedge trimmer according to an embodiment of the present invention Front view of a hedge trimmer according to an embodiment of the present invention The whole perspective view of the hedge trimmer which concerns on the modification of embodiment of this invention The bottom view of the hedge trimmer which concerns on the modification of embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings. In the present specification, description will be made assuming that the front and rear, right and left, and up and down directions are directions shown in the drawing.

FIG. 1 is an overall perspective view of a hedge trimmer 1 that is an engine working machine according to an embodiment of the present invention, and FIG. 2 is a left side view of the main body. The hedge trimmer 1 includes an engine 20 including a cylinder 14 and a muffler 15, a frame 2 that holds the engine 20, a front handle 3 provided in front of the frame 2, a rear handle 4 provided in the rear, and a rotational force of the engine 20. It has the power conversion part 5 which converts and reciprocates the blade part 6 as a working tool in the front-back direction. The hedge trimmer 1 that is an engine working machine uses a small two-cycle engine 20 housed in an engine cover 19 as a power source. In the present embodiment, the hedge trimmer 1 has a U-shaped frame 2 whose front side is opened, and a front handle 3 that an operator holds with, for example, a left hand is provided in front of the frame 2. Is provided with a rear handle 4 that is held by an operator with, for example, the left hand. A hand guard 21 is provided in front of the front handle 3 and between the blade portion 6. The hand guard 21 is configured integrally with the front handle 3 by, for example, synthetic resin integral molding, and suppresses the branch tree to be trimmed from scattering to the side of the operator holding the front handle 3. A throttle lever 13 of the engine 20 is provided below the rear handle 4. *

The engine 20 is between the front handle 3 and the rear handle 4 and is provided with a crankshaft 24 extending in the vertical direction, that is, a horizontal engine in which the axis of the cylinder 14 (reciprocating direction of the piston) is the front-rear direction. Has been. On the lower end side of the crankshaft 24, there is provided a power converter 5 that converts the rotational motion of the crankshaft 24 into reciprocating motion, and projects forward from the power converter 5 (in a direction orthogonal to the axis C of the crankshaft 24). A pair of blade parts 6 are attached to extend. The power conversion unit 5 includes a gear connected to the lower end of the crankshaft 24, a cam (not shown) that is connected to the gear and rotates, and a gear case that houses the cam. The end is attached. The blade portion 6 is configured such that the upper blade 6a and the lower blade 6b reciprocate in opposite directions, and each of the upper blade 6a and the lower blade 6b is formed such that a plurality of blades protrude in a comb shape in the left-right direction. In addition, a branch tree is cut by sandwiching an object in the front-rear direction by a plurality of blades of the upper blade 6a and a plurality of blades of the lower blade 6b. A recoil starter 23, which is a manual starter, is provided inside the engine cover 19 above the hedge trimmer 1, opposite to the power conversion unit 5, and on the upper end side of the crankshaft 24. A starter handle 23 for pulling a tow string of a recoil starter (not shown) is provided from above. The upper end of the crankshaft 24 is further provided with a cylinder 14 that also acts as a magnet rotor of the ignition device and a cooling fan 18 for forced air cooling of each part. In the engine cover 19, air windows for introducing outside air generated by the cooling fan 18 into the engine cover 19 as cooling air 8 are formed substantially radially about the rotation axis of the cooling fan 18.

The periphery of the engine 20 is covered with a cylinder 14 and a muffler 15 that are particularly heated by a synthetic resin engine cover 19. The engine cover 19 includes a cylinder cover that covers the cylinder 14 and a muffler cover 17 that covers the muffler 15. The muffler 15 is arranged on the left side of the engine 20, and the muffler 15 is surrounded by a synthetic resin muffler cover 17 that also serves as a guide for cooling air generated by the cooling fan 18, and is substantially a box except for the side facing the cylinder 14. The substantially entire shape is covered by the shape. A heat shield 25 is disposed between the muffler 15 and the cylinder 14 to partition the cylinder housing chamber that houses the cylinder 14 and the muffler housing chamber that houses the muffler 15, and the cooling generated by the cooling fan 18. After the wind is introduced into each storage chamber, it is configured to flow independently. An exhaust pipe 16 is connected to the muffler 15, extends downward from the muffler 15, is bent forward, is substantially parallel to the extending direction (front-rear direction) of the blade portion 6, and is discharged to the front side of the hedge trimmer 1. The position is determined as follows. Thereby, the exhaust direction by the exhaust pipe 16 is directed forward, and the influence of the exhaust gas on the branches can be suppressed. Further, around the exhaust pipe 16, a hand guard 21 and an air guide member 10 to be described later are disposed, and also serves as an exhaust pipe guard for protecting the exhaust pipe 16.

A carburetor 11 and an air cleaner (not shown) are provided on the right side of the engine 20, and an air cleaner chamber that houses the air cleaner is covered with a cleaner cover 12. The carburetor 11 is connected to a fuel tank 22 to hold a predetermined amount of fuel, and is connected to a throttle lever 13 of a rear handle 4 gripped by an operator, and a throttle valve in an intake passage formed inside is connected. The fuel supply amount can be controlled by operation.

Below the engine 20, the power conversion unit 5 is disposed in a space surrounded by the U-shaped frame 2, and is connected to the frame 2 by a vibration isolator 7. The anti-vibration device 7 is arranged at a total of four positions spaced apart in the front-rear and left-right directions, whereby the assembly including the engine 20, the power conversion unit 5, and the blade unit 6 includes the frame 2 having the front handle 3 and the rear handle 4. Indirectly held to suppress the transmission of vibration to the operator. The vibration isolator 7 includes a spring 7a (elastic member) that extends substantially horizontally inward from the frame 2 as a constituent element, and the engine 20, the power conversion unit 5, and the blade unit 6 by a tensile force acting in the pulling direction of the spring 7a. Is held in the frame 2. In the vibration isolator 7, one end of the spring 7a is fixed to the power conversion unit 5 side with a screw, a bolt or the like, and the other end is connected to the frame 2 via a spring holder 7b (fixing element) having a nut inside. Has been. The spring holder 7b is fixed by tightening a male screw part that fits the spring 7a on the outer periphery to hold the spring 7a, and a female screw part formed on or held on the inner periphery and a fixing means such as a bolt through the frame. Has been. Further, a front handle 3 and an air guide member 10 to be described later are attached to the frame 2 and are respectively fixed by penetrating with bolts or the like.

FIG. 3 is a front view in which a part of the engine cover 19 is omitted from the front view of the hedge trimmer 1. A wind guide member 10 that covers the bottom surface of the engine 20 is provided further below the power conversion unit 5 of the engine 20. The air guide member 10 is formed of a thin plate made of steel or the like, extends from the rear end of the muffler cover 17 to the front side of the front end in the front-rear direction, and extends in a range similar to the width of the frame 2 in the left-right direction. The air guide member 10 has a shape in which the right side, the left side, and the rear side are inclined and rise with respect to the bottom by bending, and has a concave shape with the front open. The rising shapes on the right side, the left side, and the rear side each act as an air guide wall 10 c for the cooling air 8. The air guide member 10 is attached at a place where the vibration isolator 7 is attached to the frame 2, and is held by being sandwiched between the spring holder 7 b and the frame 2. Therefore, the air guide member 10 is fixed by being fastened together with the elastic member 7 and the frame 2 with the bolts at four positions which are the four corners of the bottom surface of the frame 2 and which are separated from each other in the front, rear, left and right. In other words, the air guide member 10 is attached to the frame 2 by a fixing element common to the vibration isolator 7, thereby eliminating the need to separately provide a fixing element for attaching the air guide member 10, and reducing the number of parts. And there are effects such as weight reduction.

Most of the cooling air generated by the cooling fan 18 of the engine 20 is discharged to cool the heat dissipating fins of the cylinder 14, and the remaining cooling air 8 is led from the opening into the muffler storage chamber, as indicated by arrows. Then, it flows from above to below along the direction (axis C) in which the crankshaft 24 extends. That is, the cooling air 8 generated by the cooling fan 18 is guided into the cylinder storage chamber starting from the upper side of the carburetor 11 in the left-right direction, and the cooling air 8 discharged to the cylinder 14 side is around the cylinder portion of the cylinder 14. Then, the air flows toward the lower side of the muffler 15 in the left-right direction, and is discharged to the outside from the wind window of the engine cover 19. On the other hand, the cooling air 8 taken into the muffler storage chamber flows while diffusing along the outer wall of the muffler 15, travels to a discharge port serving as an outlet of the muffler storage chamber, and is discharged from the discharge port to the outside.

The cooling air 8 that has passed the cylinder 14 and the muffler 15 and has reached a high temperature is discharged toward the lower side of the engine 20. The cooling air 8 discharged downward, which is the bottom direction of the main body of the engine 20, is changed in direction by the air guide member 10 disposed further below the engine 20 and the frame 2 and formed at the left and right end portions and the rear end portion. After the cooling air 8 discharged downward near the end along the gentle inclination of the air guide wall 10c is gradually concentrated in the central cooling air passage 8a and flows through the bottom of the engine 20 along the front-rear direction. The air guide member 10 is discharged from the front open end. That is, an air guide member 10 is provided on the bottom surface of the frame 2 to block the cooling air 8 discharged after the engine 20 is cooled. Since it is blocked by the member 10 and changes its direction toward the front of the main body, it can be suppressed that hot cooling air 8 is concentrated and discharged on the bottom surface side of the main body.

Since the cooling air 8 discharged toward the lower side of the engine 20 is changed in flow direction by the air guide member 10, a part of the cooling air 8 is diffused by the collision and tends to flow in a direction other than the front. At this time, in order to suppress the flow of the cooling air 8 toward the carburetor 11 side, a seal portion 10 b (regulating member) is provided between the air guide member 10 and the power conversion portion 5. The seal portion 10b is made of a deformable flexible material such as sponge. Therefore, even when a load is applied to the cutting blade 6 during the operation and the power conversion unit 5 is displaced with respect to the frame 2, the power conversion unit 5 and the wind guide member 10 are deformed following the power conversion unit 5. Therefore, since the gap is not generated and the sealed state is maintained, the cooling air 8 can be suitably discharged in an arbitrary direction without leaking to the vaporizer 11 side. The seal member 10b may be formed of a rigid member by a rib or the like as long as the engine 20 and the air guide member 10 are not relatively displaced, and is integrated with the air guide member 10 or other members of the engine 20. It may be formed.

Since the air guide member 10 is attached to the frame 2 and covers the bottom surface, the protector that protects the power conversion unit 5 and the exhaust pipe 16 from contact with a planted plant or the like during the work or an impact when it is grounded to the ground. Is also configured to function. In addition, since the air guide member 10 is concave with respect to the engine 20, components such as the power conversion unit 5 and the like are connected to the air guide member 10 even when the engine 20 in operation moves with respect to the frame 2. It is configured not to touch. The wind guide member 10 is configured to cover the entire bottom surface of the engine 20, but at least the muffler 15 side is covered from the power conversion unit 5 on the side where the cooling air 8 is concentrated in the left-right direction. The cooling air path 8a shown in FIG. When the air guide member 10 does not go under the power conversion unit 5 and covers only the muffler 15 side from the power conversion unit 5 as in the embodiment of the present invention, the engine 20 moves with respect to the frame 2. In such a case, the cooling air 8 may leak from the gap between the power conversion unit 5 and the air guide member 10, so it is necessary to provide a separate seal member or the like to suppress the gap.

Next, an engine working machine according to a modification of the embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is an overall perspective view of a modified example of the present invention, and FIG. 5 is a bottom view. In the modification, the structure of the air guide member 10 is different, and a plurality of minute cooling air discharge holes 10a are provided on both the left and right sides of the bottom surface. That is, in the above-described embodiment, the cooling air 8 is directed so as to be discharged to the front side of the main body. However, in the modification, a part of the cooling air is discharged from the rear side, the side, or a plurality of the main body. It is configured. That is, the cooling air 8 that reaches the air guide member 10 has a common structure in which most of the cooling air 8 is discharged forward. It is possible to effectively reduce the temperature of the cooling air 8 that is discharged as a result of the increase in heat, and it is possible to suppress heat from being trapped inside the air guide member 10. Note that the air guide member 10 has a shape in which the center protrudes downward, and even when the air guide member 10 is grounded to the ground with the bottom as a bottom, the load received at the center is left and right by the frame 2. It becomes the structure by which a deformation | transformation etc. are suppressed by being supported. Further, since a plurality of beads 10d extending left and right are formed on the bottom surface of the air guide member 10 by pressing or the like, the rigidity is further improved with respect to the bending in the left-right direction connecting the mounting portions.

Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the air guide member 10 is configured as a separate component from the frame 2, but may be formed integrally with the frame 2. In this way, the number of parts can be reduced, and the air guide performance can be improved by suppressing the gap due to the assembly of the parts. In the embodiment of the present invention, the engine is attached to the frame via a vibration isolation structure. However, the present invention can also be applied to an engine working machine that does not have the vibration isolation structure. In this case, since it is not necessary to consider the movable range of the engine, it can be provided directly on the bottom surface of the engine, and may be fixed together with, for example, a bolt of a gear case constituting the power conversion unit.

DESCRIPTION OF SYMBOLS 1 ... Hedge trimmer, 2 ... Frame, 3 ... Front handle, 4 ... Rear handle, 5 ... Power conversion part, 6 ... Cutting blade, 7 ... Vibration isolator, 8 ... Cooling air, 8a ... Cooling air path, 9 ... Exhaust Outlet, 10 ... air guide member, 10a ... discharge hole, 10b ... flexible material, 11 ... vaporizer

Claims

An engine as a power source, a cooling fan provided above the engine, and a work tool attached to a power conversion unit provided below the engine and extending forward, are generated by the cooling fan. An engine working machine configured to cool the engine and flow downwardly, wherein an air guide member is provided to guide the cooling air that has passed through the engine forward.
The muffler is provided on one side of the engine, and the wind guide member extends at least from the end of the power conversion unit on the muffler side so as to cover a part below the muffler. The engine working machine according to 1.
The engine work machine according to claim 2, wherein the muffler includes an exhaust pipe that extends in the front-rear direction and exhausts forward, and the air guide member covers a lower portion of the exhaust pipe.
4. The air guide member according to claim 1, wherein the air guide member has a wind guide wall that rises upward at an end portion on a side away from the power conversion unit in a left-right direction of the engine. 5. The engine working machine described.
The engine work machine according to any one of claims 1 to 4, wherein the wind guide member has a wind guide wall that rises upward at an end portion on a rear side.
The engine work according to any one of claims 1 to 5, wherein the engine is supported by a frame including a handle via a vibration isolator, and the air guide member is provided on the frame. Machine.
The engine work machine according to claim 6, wherein the air guide member extends from one side to the other side in a left-right direction including a lower side of the power conversion unit.
The engine work machine according to claim 6 or 7, wherein the air guide member is fixed to the frame by a fixing element common to the vibration isolator.
The engine working machine according to claim 6 or 7, wherein the air guide member is formed integrally with the frame.
The said air guide member has a control member which controls that the cooling air which reached | attained one side of the left-right direction of the said engine goes around to the other. Engine work machine.
The engine working machine according to claim 10, wherein the restriction member is made of a flexible material provided between the power conversion unit and the air guide member.
The engine working machine according to any one of claims 1 to 11, wherein a plurality of openings are provided in the air guide member, and the cooling air is dispersed and discharged.