JP6081384B2 - Working machine - Google Patents

Description

  The present invention relates to a working machine such as a brush cutter that rotates a rotary tool by a prime mover, and more particularly, to a working machine having a prime mover at a rear end portion of an operating rod having a gripping part that is gripped by an operator.

  Patent Document 1 discloses a brush cutter for cutting grass, turf, and the like. This brush cutter has an operating rod attached with a handle gripped by an operator, an engine-type prime mover provided at the rear end portion of the operating rod, a rotary blade provided at the front end portion of the operating rod and rotated by the prime mover, And a power transmission shaft that is rotatably supported in the operating rod and transmits the drive of the prime mover to the rotary blade. In this brush cutter, when the prime mover is driven, the rotary blade is rotated by the driving force transmitted from the prime mover by the power transmission shaft, and the operator operates the handle to move the rotary blade parallel to the ground. This cuts the grass and grass that grows from the ground.

JP 2013-119847 A

  In the brush cutter described above, there has been a problem that vibration during driving of the prime mover is transmitted from the operating rod to the handle, and an operator who grips the handle is easily fatigued by the vibration. In particular, because the prime mover that rotates the rotary blade is an engine-type prime mover, the prime mover vibrates in various directions by vibrations caused by the piston reciprocating in the cylinder, vibrations of the crankshaft rotated by the reciprocating piston, and the like. However, it was easy to get tired if the worker worked for a long time. An object of the present invention is to make it difficult for vibration of a prime mover to be transmitted to a grip portion of an operating rod and to make an operator who grips the grip portion of an operating rod less likely to get tired due to vibration.

  In order to solve the above-described problems, the present invention provides an operating rod having a gripping portion to be gripped by an operator, a prime mover provided at a rear end portion of the operating rod, and a rotating shaft provided at a front end portion of the operating rod. And a power transmission shaft that is rotatably supported in the operating rod and transmits the drive of the prime mover to the rotating tool, a support body fixed to the outer periphery of the operating rod, Provided is a working machine comprising a dynamic vibration absorber having a mass body spaced apart on the outside and an elastic body that swingably supports the mass body with respect to the support body. is there.

  In the work machine configured as described above, the support body fixed to the outer peripheral portion of the operation rod, the mass body spaced apart from the outside of the support body, and the mass body can swing freely with respect to the support body. Since the dynamic vibration absorber is provided with an elastic body to be supported, the dynamic vibration absorber is a vibration transmitted to the operating rod by the mass body swinging so as to cancel the vibration caused by the drive of the prime mover and the rotation of the power transmission shaft. And vibration of the grip portion of the operating rod is also suppressed. As a result, even if the operator grips the grip portion, it is less likely to get tired by the vibration transmitted from the prime mover or the like. In particular, in this working machine, it is preferable that the elastic body supports the mass body so as to be swingable in three degrees of freedom of translation and three degrees of rotation relative to the support body. In this case, the prime mover vibrates in any direction. Even if it does, it can rock | fluctuate so that a mass body may cancel the vibration by the drive of a motor | power_engine, and rotation of a power transmission shaft. In addition, since this dynamic vibration absorber can be used with any prime mover that vibrates in any direction, this dynamic vibration absorber can be used in various types of work machines that have different vibration directions depending on the arrangement and specifications of the prime mover. It was possible and the versatility of this dynamic vibration absorber could be increased.

  In the working machine configured as described above, it is preferable that a dynamic vibration absorber is provided between the prime mover and the gripping portion. In this case, the dynamic vibration absorber is used before the vibration of the prime mover is transmitted to the gripping portion. Vibration can be reduced, and the vibration of the prime mover is less likely to be transmitted to the gripping part.

It is a perspective view of the brush cutter which is one Embodiment of the working machine of this invention. It is a longitudinal cross-sectional view along the front-back direction of an engine. (A) It is a longitudinal cross-sectional view along the front-back direction of the part which provided the dynamic vibration absorber of the operating rod, (b) It is sectional drawing of an AA line.

  Hereinafter, a brush cutter as an embodiment of the working machine of the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1, the brush cutter 10 is provided with a long and narrow cylindrical operation rod 11 extending in the front-rear direction, an engine (prime mover) 20 at the rear end portion of the operation rod 11, and a front end portion of the operation rod 11. And a cutter unit 30 having a rotary blade (rotary tool) 32 that is rotated by the engine 20. Further, a power transmission shaft 12 that transmits the drive of the engine 20 to the rotary blade 32 is rotatably supported in the operation rod 11 via a bearing member. A loop handle (gripping part) 13 having a loop shape is provided in the middle part in the front-rear direction of the operation rod 11, and a grip handle (gripping part) 14 is provided on the rear side of the loop handle 13.

  As shown in FIG. 2, the engine 20 includes a cylinder block 21 in which a crankcase 21a and a cylinder 21b are integrally provided at a lower portion, and a piston 22 can reciprocate in the vertical direction in the cylinder block 21. Contained. A combustion chamber 23 is formed between the upper surface of the piston 22 and the cylinder head 21 c at the upper end of the cylinder block 21. The cylinder head 21c is provided with an intake port that guides the air-fuel mixture generated by the carburetor to the combustion chamber 23 and an exhaust port that guides the exhaust gas generated in the combustion chamber 23 to the exhaust muffler (both not shown).

  A crankshaft 24 is provided in the crankcase 21a, and the crankshaft 24 is supported so as to be rotatable around an axis whose longitudinal direction is the axial direction. A piston 22 is connected to the crankshaft 24 via a connecting rod 25, and the reciprocating motion of the piston 22 in the vertical direction is converted into the rotational motion of the crankshaft 24. A flywheel 26 is provided at the front end of the crankshaft 24, and the flywheel 26 has a function of stabilizing the rotation of the crankshaft 24 and cooling the inside of the engine 20. A centrifugal clutch 27 is provided at the front end of the crankshaft 24 on the front side of the flywheel 26. The centrifugal clutch 27 allows the crankshaft 24 to rotate when the rotational speed of the crankshaft 24 exceeds a predetermined value. It is transmitted to the power transmission shaft 12.

  As shown in FIG. 1, the cutter unit 30 includes a front end housing 31 fixed to the front end portion of the operating rod 11, and a rotating shaft (not shown) is rotatably supported by the front end housing 31. A bevel gear (not shown) is fixed to the base end portion of the rotary shaft, and the bevel gear fixed to the front end portion of the power transmission shaft 12 is engaged with the bevel gear, and the rotation of the power transmission shaft 12 causes the bevel gear to rotate. Is transmitted to the rotating shaft. The tip of the rotating shaft protrudes below the front end housing 31, and a rotary blade 32 is attached to the tip of the rotating shaft. Although the rotary blade 32 of this embodiment uses a nylon cord, it may use a disk-shaped rotary blade having a blade portion on the outer peripheral portion.

  As shown in FIGS. 1 and 3, the operating rod 11 is provided with a dynamic vibration absorber 40, and the dynamic vibration absorber 40 is mainly for reducing vibration transmitted from the engine 20 to the operating rod 11. . The dynamic vibration absorber 40 is disposed between the grip handle 14 and the engine 20 at the rear portion of the operation rod 11. The dynamic vibration absorber 40 includes a support body 41 fixed to the outer periphery of the rear portion of the operation rod 11, a mass body 42 that is spaced apart from the support body 41, and a mass body 42 that swings the mass body 42 relative to the support body 41. And an elastic body 45 that is movably supported. The support body 41 has a short cylindrical shape, and eight mounting holes 41 a extending in the radial direction are formed at equal intervals in the circumferential direction on the periphery of the support body 41. These mounting holes 41a are for mounting the elastic body 45, and are stepped holes in which two cylindrical holes having a large outer peripheral side and a small inner peripheral side are arranged concentrically.

  The mass body 42 includes a short cylindrical inner portion 43 having a larger diameter than the support body 41 and a short cylindrical outer portion 44 fitted to the outer peripheral surface of the inner portion 3. Both outer portions 44 are structures using a metal member such as stainless steel. Eight through holes 43a extending in the radial direction are formed at equal positions in the circumferential direction at positions facing the mounting holes 41a of the support body 41 in the inner portion 43 of the mass body 42, and these through holes 43a are elastic bodies. The elastic body 45 is attached to the mass body 42 by accommodating from the middle part to the tip of 45. The outer portion 44 is fitted so as to cover the inner portion 43 from the outside, and is fixed to the inner portion 43 with screws. The outer portion 44 is provided with a through-hole 44a having a smaller diameter than the through-hole 43a at a position facing the through-hole 43a of the inner portion 43, and the elastic body 45 is prevented from being detached by the peripheral portion of the through-hole 44a. .

  The elastic body 45 is for supporting the mass body 42 on the support body 41 so as to be swingable in a state where the mass body 42 is concentrically spaced from the support body 41. The elastic body 45 is a cylindrical member made of a flexible elastic member such as rubber. The elastic body 45 is attached with the base end positioned in the mounting hole 41a of the support body 41 with the base end secured by the bottom of the mounting hole 41a of the support body 41, and the distal end attached to the outer portion of the mass body 42. In a state of being prevented from being detached by 44, the tip side from the intermediate portion is positioned and attached in the through hole 43 a of the inner portion 43 of the mass body 42. The mass body 42 is supported by the eight elastic bodies 45 so as to be swingable with respect to the support body 41 with six degrees of freedom of three degrees of translation and three degrees of rotation. The elastic body 45 is not limited to a flexible elastic member such as rubber, and may be one using a spring member such as a coil spring. In this embodiment, the eight elastic bodies 45 are arranged at equal intervals in the circumferential direction. However, the present invention is not limited to this, and three or more elastic bodies 45 may be arranged at equal intervals. Further, the shape is not limited to the cylinder, and the support body 41 and the mass body 42 may be joined (for example, integrally molded) with an elastic body such as a whole circumference rubber.

  In the brush cutter 10 configured as described above, when the engine 20 is driven, the crankshaft 24 is rotated by the piston 22 reciprocating in the vertical direction, and the crankshaft 24 is connected to the power transmission shaft 12 by the centrifugal clutch 27. Then, the power transmission shaft 12 is rotated, and the rotation of the power transmission shaft 12 is transmitted to the rotation shaft through the pair of bevel gears, and the rotary blade 32 fixed to the rotation shaft rotates. The operator holds the loop handle 13 with one hand and the grip handle 14 with the other hand, and operates the handles 13 and 14 to swing the rotary blade 32 left and right along the upper side of the ground. Grass, grass, etc. growing from the ground are cut off.

  When the engine 20 is driven, the piston 22 reciprocates in the cylinder 21b of the cylinder block 21 in the vertical direction, so that the engine 20 vibrates in the vertical direction and the crankshaft 24 rotates in the crankcase 21a. As a result, the engine 20 vibrates around the axis in the front-rear direction, and these vibrations of the engine 20 are transmitted to the operation rod 11. Further, vibration due to the rotation of the power transmission shaft 12 that is rotated by driving the engine 20 is also transmitted to the operation rod 11 through the bearing member.

  The brush cutter 10 of this embodiment includes a support body 41 fixed to the outer periphery of the operation rod 11, a mass body 42 that is spaced apart from the support body 41, and the mass body 42 with respect to the support body 41. A dynamic vibration absorber 40 having an elastic body 45 that is swingably supported is provided. The dynamic vibration absorber 40 is provided on the operation rod 11 by reducing the vibration transmitted to the operation rod 11 by swinging the mass body 42 so as to reduce the vibration caused by the driving of the engine 20 and the rotation of the power transmission shaft 12. The vibration of the loop handle 13 and the grip handle 14 is also suppressed. As a result of measuring the triaxial acceleration of the vibration of the loop handle 13 and the grip handle 14 in accordance with IEC 60335-2-91, the vibration generated in the loop handle 13 is a vibration in the vertical direction compared to the case where no dynamic vibration absorber is provided. Was suppressed to about 10%. In addition, the vibration generated in the grip handle 14 is about 8% in the left-right direction, about 9% in the front-rear direction, and about 14% in the up-down direction compared to the case without the dynamic vibration absorber. It was possible to greatly suppress. As a result, even if the operator grips the loop handle 13 and the grip handle 14, it is less likely to get tired due to vibration generated in the engine 20 or the like.

  In particular, in the brush cutter 10, the dynamic vibration absorber 40 is configured such that the mass body 42 is supported on the support body 41 by an elastic body 45 so as to be swingable in six degrees of freedom of translation and three degrees of freedom. Thereby, not only the engine 20 vibrates in the vertical direction, but also the mass body 42 is not affected even when complicated vibrations occur due to a plurality of vibrations such as when the front-rear direction vibrates in the direction of rotation about the axis. Even if the operator grips the handles 13 and 14 by swinging so as to reduce these vibrations, it becomes hard to get tired. Further, even when this dynamic vibration absorber 40 is employed in a brush cutter of a model in which the direction of vibration differs depending on the arrangement and specifications of the engine 20, for example, when the piston 22 is inclined from an upright state, The vibration transmitted to the operation rod 11 can be suppressed, and the versatility of the dynamic vibration absorber 40 can be increased.

  In the brush cutter 10, the dynamic vibration absorber 40 is provided between the engine 20 and the grip handle 14 (including the loop handle 13). Accordingly, the dynamic vibration absorber 40 can reduce the vibration transmitted from the engine 20 to the operating rod 11 before transmitting it to the grip handle 14 and the loop handle 13, and the vibration of the engine 20 is applied to the grip handle 14 and the loop handle 13. It became more difficult to communicate. The dynamic vibration absorber 40 is optimally provided between the engine 20 of the operation rod 11 and the grip handle 14 (including the loop handle 13), but is not limited to this. For example, the dynamic vibration absorber 40 is provided. Even if it is provided between the loop handle 13 and the grip handle 14 of the operating rod 11 or in front of the loop handle 13, the vibration transmitted from the engine 20 to the operating rod 11 can be reduced.

  Further, as a method for making it difficult to transmit the vibration of the engine 20 or the like to the handles 13 and 14, a flexible elastic member such as rubber is interposed between the operation rod 11 and the handles 13 and 14. It is also possible to suppress vibration from being transmitted from the operation rod 11 to the handles 13 and 14. However, in this case, the handles 13 and 14 may be swayed by the flexible elastic member interposed between the operation rod 11 and the operability of the handles 13 and 14 may be reduced. On the other hand, if a dynamic vibration absorber 40 is provided on the operation rod 11 as in the present invention, a flexible elastic member such as rubber must be interposed between the handles 13 and 14 and the operation rod 11. Therefore, the handles 13 and 14 can be fixed to the operation rod 11 in a stable state, vibrations transmitted to the handles 13 and 14 can be reduced, and the operability of the handles 13 and 14 can be maintained. I was able to balance both.

  In the above embodiment, the brush cutter using the engine as the prime mover has been described. However, the present invention is not limited to this, and the operation of the electric motor can be performed even when the brush cutter uses the electric motor as the prime mover. The vibration due to the rotation of the power transmission shaft and the vibration due to the rotation of the power transmission shaft can be reduced, and the same effect can be obtained.

  In the above embodiment, the operation rod 11 uses a straight cylindrical tube member, but the present invention is not limited to this, and uses a bent tube member having a curved tip. In this way, the same effect can be obtained.

  In the above embodiment, the brush cutter using the loop handle 13 and the grip handle 14 as the grip portion has been described. However, the present invention is not limited to this, and only one of the loop handle 13 and the grip handle 14 is used. The same effect can be obtained even with a brush cutter that employs a U-shaped handle instead of the employed brush cutter or the loop handle 13 and the grip handle 14.

  In the above embodiment, a brush cutter using a rotary blade as a rotary tool has been described. However, the working machine of the present invention is not limited to this, and a polisher such as a polisher or a grinder using a polisher as a rotary tool. It can be applied to the above.

 DESCRIPTION OF SYMBOLS 10 ... Work machine (brusher), 11 ... Operation rod, 12 ... Power transmission shaft, 13 ... Gripping part (loop handle), 14 ... Gripping part (grip handle), 20 ... Motor (engine), 32 ... Rotary tool ( Rotating blade), 40 ... dynamic vibration absorber, 41 ... support, 42 ... mass body, 45 ... elastic body.

Claims (3)

An operating rod having a gripping part to be gripped by an operator;
A prime mover provided at the rear end of the operating rod;
A rotary tool provided at the front end of the operating rod and rotated by the prime mover;
In a working machine comprising a power transmission shaft that is rotatably supported in the operation rod and transmits the drive of the prime mover to the rotary tool,
A support body fixed to the outer periphery of the operation rod; a mass body spaced apart from the support body; and an elastic body that swingably supports the mass body with respect to the support body. A working machine comprising the dynamic vibration absorber. The working machine according to claim 1,
The working machine characterized in that the elastic body supports the mass body so as to be swingable with respect to the support body in three degrees of translation and three degrees of rotation. The working machine according to claim 1 or 2,
A working machine, wherein the dynamic vibration absorber is provided between the prime mover and the grip portion.

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