WO2009150823A1 - Mécanisme amortisseur de vibrations pour tondeuse, arbre de transmission de puissance situé côté lames de coupe, arbre de transmission de puissance et ensemble tambour d'embrayage centrifuge - Google Patents

Mécanisme amortisseur de vibrations pour tondeuse, arbre de transmission de puissance situé côté lames de coupe, arbre de transmission de puissance et ensemble tambour d'embrayage centrifuge Download PDF

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Publication number
WO2009150823A1
WO2009150823A1 PCT/JP2009/002591 JP2009002591W WO2009150823A1 WO 2009150823 A1 WO2009150823 A1 WO 2009150823A1 JP 2009002591 W JP2009002591 W JP 2009002591W WO 2009150823 A1 WO2009150823 A1 WO 2009150823A1
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WO
WIPO (PCT)
Prior art keywords
transmission shaft
side transmission
cutting blade
shaft portion
prime mover
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Application number
PCT/JP2009/002591
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English (en)
Japanese (ja)
Inventor
今泉敏明
内田晃生
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株式会社ファインスティールエンジニアリング
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Application filed by 株式会社ファインスティールエンジニアリング filed Critical 株式会社ファインスティールエンジニアリング
Publication of WO2009150823A1 publication Critical patent/WO2009150823A1/fr

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    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01D—HARVESTING; MOWING
    • A01D34/00—Mowers; Mowing apparatus of harvesters
    • A01D34/835—Mowers; Mowing apparatus of harvesters specially adapted for particular purposes
    • A01D34/90—Mowers; Mowing apparatus of harvesters specially adapted for particular purposes for carrying by the operator
    • A01D34/905—Vibration dampening means

Definitions

  • the present invention relates to a vibration damping mechanism, a cutting blade side transmission shaft, a transmission shaft, and a centrifugal clutch drum assembly in a brush cutter that cuts weeds by rotating a cutting blade with the power of a prime mover such as a two-cycle engine.
  • the prime mover is connected to the cutting blade via a clutch and a transmission shaft, and the power generated by the prime mover is transmitted to the cutting blade via the transmission shaft to rotate the cutting blade.
  • the transmission shaft of such a brush cutter is very thin and has a total length of about 1.5 m, and is arranged inside the operation rod main body so as not to be exposed to the outside.
  • a handle is attached to the main body of the operation rod, and an operator operates the handle to trim away weeds and the like.
  • the vibration of the prime mover is transmitted to the operating rod and further to the handle. Therefore, this vibration causes a decrease in the operability of the operator and an increase in fatigue, and may cause white wax disease in extreme cases.
  • a cylindrical coupling body coupled to a centrifugal clutch a movable sleeve coupled to the cylindrical coupling body through a pin so as to be movable in the axial direction, a cutting blade side spline-connected to the movable sleeve in the movable sleeve
  • Patent Document 2 A vibration absorbing joint having a transmission shaft is known (Patent Document 2).
  • a compression coil spring is disposed between the cylindrical coupling body and the movable sleeve in the cylindrical coupling body.
  • a triangular window is formed in the cylindrical coupling body, and the aforementioned pin is engaged with the window to transmit the rotation.
  • the pin moves along the side of the triangular window. That is, the movable sleeve is slightly displaced in the rotational direction relative to the cylindrical coupling body in the cylindrical coupling body and moves slightly in the axial direction to compress the compression coil spring. In the non-addition state, the movable sleeve does not press the compression coil spring, but when a load is applied, the movable sleeve presses the compression coil spring to absorb rotational torque fluctuations.
  • Patent Document 1 The portable brush cutter disclosed in Patent Document 1 described above is effective in that it is difficult to propagate the vibration of the prime mover to the operating rod, but it does not deal with torque fluctuation (torsional vibration) of the transmission shaft. No effect can be expected for torsional vibration.
  • the vibration-absorbing joint disclosed in Patent Document 2 has a temporary effect on torsional vibration but transmits rotation through a rigid body called a pin. Since the transmission shaft and the transmission shaft are closely fitted together, there is a problem that it is difficult to absorb the bending vibration of the transmission shaft caused by the load fluctuation of the cutting blade. In addition, the number of parts and assembly man-hours are large, the structure is complicated, and there are problems that processing is difficult and expensive.
  • the present invention has been made in view of the above circumstances, and its object is to reduce the number of parts, the structure is simple, the assembly is easy, and the vibration damping mechanism of the brush cutter, and the cutting blade side used in the mechanism. It is an object of the present invention to provide a transmission shaft, a transmission shaft using a vibration damping mechanism, and a centrifugal clutch drum assembly for a brush cutter.
  • Another object of the portable brush cutter of the present invention is to provide a vibration damping mechanism for a brush cutter that can mitigate both engine vibration and torsional vibration of the transmission shaft, and a cutting blade side transmission shaft and vibration used therein.
  • An object of the present invention is to provide a centrifugal clutch drum assembly for a transmission shaft and a brush cutter using a buffer mechanism.
  • a vibration damping mechanism of a first brush cutter is a vibration damping mechanism provided on a transmission shaft of a brush cutter that transmits a rotational force of a prime mover to a cutting blade via a transmission shaft,
  • a prime mover side transmission shaft portion having a spiral groove formed on the outer periphery, connected to the prime mover;
  • One end side is screwed into the spiral groove of the power transmission side transmission shaft portion, the other end side is screwed into the spiral groove of the cutting blade side transmission shaft portion, and a predetermined portion is provided between at least some of the ring portions that are not screwed into the spiral groove.
  • a coil spring provided with a gap, The rotation of the prime mover side transmission shaft portion is transmitted to the cutting blade side transmission shaft portion via a coil spring.
  • the separation of the spiral grooves formed in the both transmission shaft portions is not limited as long as the coil spring exists over the separation portions, and as long as that is the case, what is the specific mode of separation? It may be a thing.
  • prime mover side transmission shaft portion and the cutting blade side transmission shaft portion refer to the transmission shaft portion on the prime mover side to which the coil spring of the vibration damping mechanism of the present invention is attached, and the transmission shaft portion on the cutting blade side, respectively.
  • the radius of each transmission shaft portion toward the tip is provided on the outer periphery of the tip portion of each of the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion covered by the coil spring. It is preferable that a taper facing inward is formed.
  • the spiral groove of the prime mover side transmission shaft portion is formed on the outer periphery of the tip portion facing the cutting blade side transmission shaft portion of the prime mover side transmission shaft portion, and At the end is formed a stopper part where one end of the coil spring abuts, and the spiral groove of the cutting blade side transmission shaft part is formed on the outer periphery of the tip part facing the prime mover side transmission shaft part of the cutting blade side transmission shaft part.
  • a stopper portion with which the other end of the coil spring abuts can be formed at the rear end.
  • spiral groove of the prime mover side transmission shaft portion and / or the cutting blade side transmission shaft portion may be formed such that ring portions of coil springs screwed into the spiral groove are in close contact with each other.
  • the vibration damping mechanism of the second brush cutter is a vibration damping mechanism provided on the transmission shaft of the brush cutter for transmitting the rotational force of the prime mover to the cutting blade through the transmission shaft in the same manner as described above.
  • a prime mover-side transmission shaft connected to the prime mover, having a spring insertion portion protruding so as to face the opposite side of the prime mover, and a contact portion for receiving one end of a wire rod of a coil spring rotatably fitted therein Part, A spring insertion portion projecting so as to face the spring insertion portion of the prime mover side transmission shaft portion, and a contact portion for receiving the other end of the wire rod of the coil spring rotatably fitted therein,
  • a cutting blade side transmission shaft portion connected to the blade; One end side is provided with a spring insertion portion of the prime mover side transmission shaft portion, and the other end side is provided with a coil spring fitted into the spring insertion portion of the cutting blade side transmission shaft portion, When the prime mover side transmission shaft portion is rotate
  • the above-mentioned “rotatably fitted” means that the coil spring can be rotated around the spring insertion portion inserted therein by setting the inner diameter of the coil spring larger than the outer diameter of the spring insertion portion. It refers to the state in which both are combined with the state.
  • a sleeve that covers at least a part of the coil spring at a predetermined interval from the outer periphery thereof is disposed.
  • the vibration damping mechanism of the third brush cutter according to the present invention includes a spring insertion portion in which the vibration cushioning mechanism of the second brush cutter according to the present invention is formed on each of the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion.
  • the coil spring is held between both transmission shaft portions by passing the coil spring through the coil spring, whereas the coil spring is held between both transmission shaft portions by a simple sleeve.
  • a vibration damping mechanism provided on the transmission shaft of the brush cutter for transmitting the rotational force of the prime mover to the cutting blade through the transmission shaft as described above, Having a contact portion for receiving one end of the wire rod of the coil spring, and a prime mover side transmission shaft portion connected to the prime mover;
  • a cutting blade side transmission shaft portion connected to the cutting blade having a contact portion for receiving the other end of the wire rod of the coil spring, arranged to face the prime mover side transmission shaft portion;
  • Between the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion, one end and the other end of the wire are respectively an abutting portion of the prime mover side transmission shaft portion and an abutting portion of the cutting blade side transmission shaft portion.
  • a coil spring arranged to be received by A sleeve that is held by the prime mover side transmission shaft portion and / or the cutting blade side transmission shaft portion and covers at least a part of the coil spring at a predetermined interval from the outer periphery;
  • the prime mover side transmission shaft portion is rotated to push one end of the wire of the coil spring through the contact portion, the rotation is transmitted to the cutting blade side transmission shaft portion through the coil spring. It is characterized by this.
  • either the end of the prime mover side transmission shaft portion or the cutting blade side transmission shaft portion facing each other is disposed.
  • a recess having a circular cross section that is concentric with the transmission shaft portion is formed, and an end of the other transmission shaft portion is configured to have a cylindrical convex portion that is inserted into the recess and has an outer diameter smaller than the inner diameter of the recess. It is desirable that
  • the first cutting blade side transmission shaft according to the present invention includes the cutting blade side transmission shaft portion constituting the first, second or third vibration damping mechanism according to the present invention described above, and the cutting blade side transmission shaft.
  • a transmission long portion connected to the shaft portion and transmitting the rotation of the cutting blade side transmission shaft portion to the cutting blade is provided.
  • the second cutting blade side transmission shaft according to the present invention includes a cutting blade side transmission shaft portion constituting the first vibration damping mechanism according to the present invention, and the cutting blade side transmission shaft portion coupled to the cutting blade side transmission shaft portion.
  • the transmission shaft of the brush cutter according to the present invention is attached to the first, second or third vibration damping mechanism according to the present invention and the cutting blade side transmission shaft portion of the vibration damping mechanism, and the cutting blade side transmission shaft portion is attached. And a transmission elongate portion for transmitting the rotation to the cutting blade.
  • the transmission shaft means a shaft that transmits the rotation of the prime mover to the cutting blade.
  • a shaft portion that includes the prime mover side transmission shaft portion and is connected to the centrifugal clutch drum, and a cutting blade side transmission shaft portion.
  • the shaft portion including the transmission long portion and the shaft portion until the shaft is connected to the cutting blade unit.
  • the centrifugal clutch drum assembly for a first brush cutter includes a prime mover side transmission shaft portion and a prime mover side transmission shaft portion constituting the first, second or third vibration damping mechanism according to the present invention. And a centrifugal clutch drum connected thereto.
  • a second centrifugal clutch drum assembly includes a prime mover side transmission shaft portion constituting the first vibration damping mechanism according to the present invention, a centrifugal clutch drum coupled to the prime mover side transmission shaft portion, and the prime mover. And a coil spring having one end screwed into the spiral groove of the side transmission shaft portion.
  • the second centrifugal clutch drum assembly according to the present invention may be configured to include a cutting blade side transmission shaft portion in which the other end side of the coil spring is screwed into the spiral groove.
  • the prime mover side transmission shaft portion having the spiral groove formed on the outer periphery, and the spiral groove formed apart from the spiral groove of the prime mover side transmission shaft portion.
  • a cutting blade side transmission shaft portion having one end side screwed into the spiral groove of the prime mover side transmission shaft portion, the other end side screwed into the spiral groove of the cutting blade side transmission shaft portion, and a ring portion of the portion not screwed into the spiral groove
  • a coil spring provided with a predetermined interval between them, whereby the rotation of the prime mover side transmission shaft portion is transmitted to the cutting blade side transmission shaft portion via the coil spring, and the following effects are produced.
  • various vibrations such as transmission shaft torsional vibration and bending vibration caused by engine rotation unevenness and cutting blade load fluctuations cause gaps in the coil spring between the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion.
  • the coil spring is twisted so that the portion narrows or widens, the coil spring is bent and absorbed in the axial direction.
  • the rotation is transmitted by the coil spring and the vibration is absorbed by the torsion, so that a vibration buffer mechanism having a small number of parts, a simple configuration, easy assembly, and low cost can be obtained.
  • the spiral groove of the prime mover side transmission shaft portion is formed on the outer periphery of the tip end portion of the prime mover side transmission shaft portion, and one end of the coil spring is provided at the rear end of the tip end portion.
  • the stopper part that abuts is formed, the spiral groove of the cutting blade side transmission shaft part is formed on the outer periphery of the tip part of the cutting blade side transmission shaft part, and the stopper part that the other end of the coil spring abuts is formed at the rear end of the tip part
  • it can be easily attached by simply screwing the coil spring into the spiral groove, and the structure is simple and the cost is low. Also, replacement of parts is extremely easy.
  • the spiral groove of the prime mover side transmission shaft portion and / or the cutting blade side transmission shaft portion is closely connected to the ring portion of the coil spring screwed into the spiral groove.
  • the coil spring is formed so that the wire rod (ring portion) does not move along the winding direction of the coil spring, the portion of the coil spring screwed into the spiral groove is prevented from being twisted. Is done.
  • the spring insertion portion projecting so as to face the side opposite to the prime mover and one end of the wire rod of the coil spring rotatably fitted therein are provided.
  • a prime mover side transmission shaft portion having an abutting portion to be received, a spring insertion portion projecting so as to face the spring insertion portion, and an abutting portion for receiving the other end of the wire rod of the coil spring rotatably fitted therein A cutting blade side transmission shaft portion, and a coil spring fitted at one end side to the spring insertion portion of the prime mover side transmission shaft portion and the other end side to the spring insertion portion of the cutting blade side transmission shaft portion,
  • the transmission shaft portion is configured to transmit the rotation to the cutting blade side transmission shaft portion via the coil spring when the transmission shaft portion is rotated to push one end of the wire rod of the coil spring via the contact portion. Therefore, the following effects are achieved.
  • the prime mover side transmission shaft portion having a contact portion for receiving one end of the coil spring wire, and the contact portion for receiving the other end of the coil spring wire.
  • the contact portion of the prime mover side transmission shaft portion and the cutting blade side transmission are the contact portion of the prime mover side transmission shaft portion and the cutting blade side transmission, respectively.
  • a coil spring disposed in a state of being received by the contact portion of the shaft portion, and a motor-side transmission shaft portion and / or a cutting blade-side transmission shaft portion, and at least a part of the coil spring is predetermined from the outer periphery thereof.
  • the structure is such that the rotation is transmitted by pushing and rotating the coil spring. Therefore, the coil spring needs to be firmly fixed to both the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion. There is no. Therefore, in the second vibration damping mechanism, the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion basically only need to include the spring insertion portion and the abutting portion described above, and the structure is extremely simple. It will be something.
  • the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion are basically provided with only the abutting portion, and a simple spring for holding the coil spring thereon. Since the sleeve only needs to be disposed, the third vibration damping mechanism also has a very simple structure.
  • the second and third vibration damping mechanisms can be sufficiently reduced in size and cost, and can be easily assembled and disassembled.
  • the coil spring is pushed and rotated as described above, that is, the rotation is transmitted by applying a force in the compression direction to the coil spring wire.
  • the coil spring is elastically deformed so as to increase its diameter and performs a buffering action.
  • the coil spring is deformed too much, there is a possibility that the ring portion of the expanded spring will be uncovered, and a situation may occur in which it rides on the adjacent ring portion.
  • a sleeve that covers at least a part of the coil spring at a predetermined interval from the outer periphery thereof is disposed.
  • the diameter of the ring portion of the coil spring is restricted by the sleeve, so that it is possible to reliably prevent the above-described undesirable situation from occurring.
  • one of the end portions of the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion facing each other. Is formed with a cylindrical convex portion having an outer diameter smaller than the inner diameter of the concave portion, which is inserted into the concave portion at the end of the other transmission shaft portion. Since the relative displacement in the direction perpendicular to the axial direction of the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion is restricted within the gap between the concave portion and the cylindrical convex portion, Damage and deformation of the coil spring due to large displacement can be prevented.
  • the concave portion and the cylindrical convex portion are fitted as described above, they are relatively displaceable to some extent in the direction perpendicular to the axial direction within the range of the gap. Impact can be mitigated. Furthermore, if this configuration is adopted, the coil spring can be made longer, and the degree of vibration and shock absorption can be increased. That is, even if the coil spring is lengthened, the coil spring is supported over the entire length by the transmission shaft portion passing through the coil spring, so that the coil spring is prevented from being violated (vibrated).
  • Sectional drawing which shows the outline of the principal part of the brush cutter which is an example of this invention
  • Sectional drawing which shows the centrifugal clutch case part which comprises the vibration damping mechanism which becomes an example of this invention
  • the enlarged view which shows the end surface of the spring mounting part of the centrifugal clutch case part shown by FIG. 2A
  • Partial sectional view showing another modification of the coil spring The figure which shows the transmission shaft which attached the spring mounting part to the transmission long part The figure which shows the transmission shaft which becomes an example of this invention
  • the partially broken side view which shows another embodiment of the vibration damping mechanism by this invention
  • the perspective view which shows a part of vibration damping mechanism of FIG.
  • the perspective view which shows another part of the vibration buffering mechanism of FIG.
  • the partially broken side view which shows another embodiment of the vibration damping mechanism by this invention The partially broken side view which shows another embodiment of the vibration damping mechanism by this invention
  • the partially broken side view which shows another embodiment of the vibration damping mechanism by this invention 13 is an enlarged side sectional view showing the main part of the mechanism shown in FIG.
  • FIG. 1 is a cross-sectional view schematically showing a main part of a brush cutter as an example of the present invention.
  • the illustrated brush cutter 30 includes an operation rod 1 made of, for example, an aluminum pipe, a prime mover 2 that is simply shown as a rectangular block, and a cutting blade unit 3.
  • the operating rod 1 includes a pipe-shaped operating rod main body 4 and a transmission elongated portion 20 that is rotatably supported inside the operating rod main body 4 via a bearing 5.
  • the transmission elongate part 20 becomes a part of the transmission shaft 6 mentioned later.
  • the bearing 5 is made of an elastic rubber and an oil-impregnated metal that supports a transmission elongate portion 20 to be described later inside the elastic rubber.
  • a bevel gear 7 connected to the transmission elongated portion 20 is rotatably supported at the distal end portion (cutting blade unit 3 side) of the operating rod 1, and the base end portion (prime unit 2 side) is a centrifugal clutch. Attached to the case portion 8.
  • a centrifugal clutch drum 34 described later is accommodated in the centrifugal clutch case portion 8.
  • the prime mover 2 is attached to the base end side of the operating rod 1 via a centrifugal clutch case portion 8.
  • an internal combustion engine that generates a rotational force such as a two-cycle engine is used.
  • the cutting blade unit 3 is attached to the distal end side of the operation rod 1.
  • the cutting blade unit 3 includes a case 9, a cutting blade support shaft 10 rotatably supported in the case 9, a bevel gear 11 fixed to the base end side of the cutting blade support shaft 10, and a distal end side.
  • the bevel gear 11 is engaged with the bevel gear 7 connected to the transmission long portion 20.
  • a part of the vibration damping mechanism 21 of the present invention indicated by a one-dot chain line is disposed on the proximal end side of the transmission long portion 20.
  • the angle formed between the transmission elongated portion 20 and the cutting blade support shaft 10 is a right angle, but is not limited to a right angle, and an appropriate angle such as 120 degrees (60 degrees) is set. Is done.
  • FIG. 2A is a partially enlarged cross-sectional view of the brush cutter 30 (FIG. 1) showing the centrifugal clutch case portion 8 and the vibration damping mechanism 21 in an enlarged manner.
  • FIG. 2B is an enlarged view showing an end face of the spring mounting portion 46 of the transmission long portion 20.
  • the centrifugal clutch case portion 8 has a housing 32 fixed to the prime mover 2 with screws or the like, and a drum (centrifugal clutch drum) 34 constituting a centrifugal clutch is rotatably accommodated in the housing 32.
  • the housing 32 is integrally formed with the flange 32a fixed to the prime mover 2 and the flange 32a, and is fitted to the large diameter portion 32b for accommodating the drum 34, the reduced diameter portion 32c for accommodating and supporting a bearing described later, and the operation rod main body 4.
  • the mounting portion 32d is provided.
  • the large diameter portion 32b, the reduced diameter portion 32c, and the mounting portion 32d are formed concentrically.
  • the mounting portion 32 d has a length that includes the spring mounting portion 46.
  • the drum 34 is a flat annular shape opened to the prime mover side, and accommodates a rotating element (not shown) of the centrifugal clutch inside.
  • This rotating element is connected to the prime mover 2, and when a predetermined rotation is reached, the rotating element comes into frictional contact with the inner surface of the peripheral wall 34 a of the drum 34 to rotate the drum 34.
  • An opening 34b is formed at the center of the drum 34, and a rotary shaft (motor-side transmission shaft) 36 is connected to the opening 34b.
  • the rotary shaft 36 is inserted into the opening 36 of the drum 34 and welded to form a low-profile cylindrical protrusion 36a, a large-diameter base end portion 36b in contact with the flat main surface 34c of the drum 34, and the base end portion 36b.
  • a support portion 36c having a diameter smaller than that of the base end portion 36b and a spiral groove portion 36d having a diameter smaller than that of the support portion 36c and formed continuously with the support portion 36c are formed.
  • the support portion 36 c is a portion supported by the bearing 40.
  • An annular groove 36e is formed at the end of the support part 36c on the spiral groove part 36d side, and a retaining ring 38 is provided in the annular groove 36e.
  • the above-described bearing 40 is crowned between the end face 36h of the base end portion 36b and the retaining ring 38 to restrict the movement in the axial direction.
  • a coil spring 44 described later is screwed into the spiral groove portion 36d.
  • the outer peripheral side of the bearing 40 is disposed in the reduced diameter portion 32c of the housing 32 described above.
  • An annular groove 32f is formed on the inner circumferential surface 32e of the reduced diameter portion 32c on the drum 34 side, and a retaining ring 42 is attached to the annular groove 32f.
  • the bearing 40 is fixed so as not to move in the axial direction by the retaining ring 42 and the inner surface 32g facing the prime mover of the reduced diameter portion 32c.
  • the drum 34 and the rotation shaft 36 can rotate coaxially with the reduced diameter portion 32 c in the housing 32.
  • a spiral groove 36f into which the coil spring 44 is screwed is formed in the spiral groove portion 36d over a predetermined length of the prime mover side transmission shaft portion.
  • the cross-sectional shape of the spiral groove 36 f is substantially the same as the outer shape of the coil spring 44.
  • the coil spring 44 is composed of, for example, a wire having a circular cross section.
  • the coil spring 44 has both ends in the longitudinal direction wound closely with a wire (ring) and a middle portion in which the wires are slightly separated from each other, so-called It is wound in a sparse state.
  • the coil spring 44 is screwed into the spiral groove 36f.
  • the proximal end side (one end side) 44a of the coil spring 44 is connected to the end surface (stopper portion) 36g of the support portion 36c of the rotating shaft 36. It abuts and the coil spring 44 is prevented from further rotating.
  • the coil spring 44 is also screwed to the transmission long portion 20. The portion where the wire is wound closely does not move along the winding direction of the wire, and the attachment to the spiral groove 36 is firm.
  • the transmission long portion 20 side has a spring mounting portion 46 attached to the proximal end side of the transmission long portion 20.
  • the long transmission portion 20 and the spring mounting portion 46 serve as the cutting blade side transmission shaft 6a.
  • the cutting blade side transmission shaft 6a is a part of the transmission shaft 6, and the transmission elongated portion 20 has an outer diameter of about 8 mm and a length of about 1.5 m, which is very thin and rotates at a high speed of 8000 to 12000 rpm. Therefore, as shown in FIG. 1, the bearing 5 is designed so that the inner diameter of the bearing 5 is substantially the same as the outer diameter of the transmission long portion 20 and is supported with almost no gap.
  • the spring mounting portion 46 is formed with a spline groove 46a extending in the axial direction at the center, and has a large-diameter base portion 46b and a spiral groove portion 46c having a smaller diameter than the base portion 46b on the base end side of the base portion 46b.
  • the spiral groove portion 46c has the same shape as the spiral groove portion 36d, and the other end portion of the coil spring 44 is screwed thereto. At this time, the outermost end portion 44b of the coil spring 44 is screwed so as to come into contact with an end surface (stopper portion) 46d facing the prime mover side of the base portion 46b. Thereby, the vibration damping mechanism 21 is configured.
  • the screw directions of the spiral grooves 36f and 46f described above are formed in a direction in which the screw spring 44, the rotary shaft 36, and the transmission shaft 6 are more firmly engaged with each other by the rotation of the prime mover 2.
  • the connection between the spring mounting portion 46 and the transmission long portion 20 may be spline connection, or may be fixed integrally by welding.
  • the spring mounting portion 46 becomes a part of the transmission long portion 20 by the coupling of the spring mounting portion 46 and the transmission long portion 20. Further, the operating rod main body 4 is fixed in the mounting portion 32d of the housing 32 by appropriate means such as screwing, interference fitting, and screwing.
  • the vibration damping mechanism 21 includes the rotation shaft 36, the coil spring 44, and the spring mounting portion 46.
  • the rotation of the prime mover 2 is transmitted to the rotary shaft 36 via the drum 34 in the centrifugal clutch case portion 8, and further transmitted to the transmission elongated portion 20 via the coil spring 44. Is transmitted and the cutting blade 12 is rotated. If the torque varies due to the vibration of the prime mover 2 during rotation, the variation in rotation due to incomplete combustion, the variation in resistance of the cutting blade 12, etc., the variation may become torsional vibration or flexural vibration and cause vibration in the operating rod 1. It becomes. However, this vibration is absorbed by the vibration damping mechanism 21 of the present invention.
  • the drum 34 starts to rotate rapidly.
  • the rotating shaft 36 integrated with the drum 34 also rotates at the same time, and the rotation is transmitted to the transmission elongated portion 20 via the coil spring 44.
  • the transmission long portion 20 is in a stopped state until then, and the length is long, and the cutting blade unit 3 is attached to the distal end portion. Therefore, the rotating system including the transmission long portion 20 and reaching the cutting blade unit 3.
  • the inertial mass at the time of stationary is large. Accordingly, the rotation of the rotary shaft 36 cannot be followed instantaneously and a slight delay occurs, but this rotation delay is normally transmitted to the operator via the operation rod 1 as an impact.
  • the coil spring 44 transmits the rotation, the delay in the rotation is absorbed by the twist of the coil spring 44.
  • the wire rods are in close contact with each other at both ends in the longitudinal direction of the coil spring 44, and the end portions 44a and 44b are in contact with the end faces 36g and 46d serving as the stoppers described above.
  • the coil spring 44 is twisted in the direction in which the gap between the wires (rings) that are separated from each other is narrowed at the intermediate portion in the longitudinal direction of the coil spring 44. It is conceivable that the degree of torsion is twisted to a position where the magnitude of the difference in torque between the rotary shaft 36 and the cutting blade side transmission shaft 6a and the generation of torque due to the torsion of the coil spring 44 are balanced.
  • no matter how large the torque of the rotating shaft 36 is, if the wire rods of the coil spring 44 that are spaced apart from each other come into contact with each other, further twisting is prevented, so that excessive deformation of the coil spring 44 is prevented.
  • the vibration damping mechanism 21 of the present invention has a simple structure and does not wear mechanically operating parts or parts, so that it does not wear and has high durability.
  • a taper 36 i is formed on the outer periphery of the distal end portion of the rotating shaft 36. Since there is this taper 36i, it is prevented that the edge of the tip end of the rotating shaft 36 abuts against the wire rod of the coil spring 44 from the inside and breaks the wire rod during rotation. For the same reason, a taper 46 g is also formed on the outer periphery of the tip of the spring mounting portion 46. As a result, the durability of the vibration damping mechanism 21 is further improved.
  • FIG. 3 the difference between the embodiment shown in FIG. 3 and the embodiment shown in FIGS. 2A and 2B is the relationship between the rotating shaft (the prime mover side transmission shaft) 136 and the spring mounting portion 146. Since other configurations are the same, the description of the same parts will be briefly described.
  • the housing 32 of the centrifugal clutch case 8 is not shown.
  • the vibration buffer mechanism 121 includes a rotating shaft 136 having a spiral groove 136 f connected to the drum 134, a spring mounting portion 146 combined with the rotating shaft 136, and a coil spring 144 that connects the rotating shaft 136 and the spring mounting portion 146.
  • the drum 134 is fixed to the rotating shaft 136 of the vibration damping mechanism 121 to constitute the centrifugal clutch drum assembly 135 of the present invention.
  • the retaining ring 138 fixes the bearing 140 to the rotating shaft 136 as in the embodiment of FIGS. 2A and 2B, but the bearing 140 is not a component of the centrifugal clutch drum assembly 135.
  • centrifugal clutch drum assembly of the present invention may have a configuration in which the drum 134 and the rotary shaft 136 are combined in addition to the above configuration, and may further have a configuration in which the coil spring 144 is screwed to the rotary shaft 136.
  • the rotating shaft 136 has a hollow pipe shape having a through hole (a concave portion having a circular cross section) 136j concentrically with the rotating shaft 136.
  • the spring mounting portion 146 has a female spline groove 146a connected to the transmission long portion 20 (FIG. 2A), and is a columnar shape inserted into the aforementioned through hole 136j on the side facing the rotating shaft 136. 146h (cylindrical convex portion) is formed.
  • the spring mounting portion 146 has a spiral groove portion 146c formed with a spiral groove 146f.
  • the convex portion 146h is coaxially disposed in the through hole 136j, and the gap between the convex portion 146h and the inner surface of the through hole 136j G is about 0.2 to 0.5 mm.
  • the rotation center axes of the prime mover side transmission shaft portion and the cutting blade side transmission shaft portion are positioned on the same axis.
  • the coaxiality at the time of rotation of the rotating shaft 136 and the transmission long portion 20 is ensured, and vibration is further reduced. That is, excessive deflection vibration in the direction perpendicular to the axis within the predetermined range of the gap G is restricted, and vibration is absorbed in the gap G. Therefore, damage and deformation of the coil spring 144 can be prevented and flexural vibration can be mitigated.
  • the diameter of the wire rod of the coil spring 144 is about 2 mm to 3 mm, and the distance Sa between the wire rods in the intermediate portion is about 0.2 to 0.5 mm. If the distance Sa is too large, the wire may be twisted. Therefore, it is preferable that the wire rods come into contact with each other when the relative rotation between the rotary shaft 136 and the cutting blade side transmission shaft 6a is about 1/2. In other words, vibrations such as torque fluctuations can be absorbed if the relative rotation difference is half a rotation.
  • a portion of the spring mounting portion 146 reaching the convex portion 146h excluding the spiral groove portion 146c is a transition portion 146i having a smooth outer surface.
  • the diameter of the transition portion 146i is smaller than that of the spiral groove portion 146c so that the twist of the coil spring 144 is not hindered.
  • the distance S between the outer surface of the maximum diameter portion of the transition portion 146i and the inside of the coil spring 144 is about 0.2 to 0.5 mm.
  • the outer surface of the transition portion 146i is tapered toward the tip of the transition portion 144i along the axial direction. This taper may be formed not only on the entire transition portion 146i but only on the tip, that is, near the end surface 146j of the transition portion 146i.
  • a gap Ga is formed between the end surface 146j of the transition portion 146i facing the rotation shaft 136 and the end surface 136k of the rotation shaft 136. This is because the rotation shaft 136 and the spring mounting portion 146 are relatively accessible in the axial direction as the coil spring 144 is twisted.
  • the dimension of the gap Ga is about 0.2 to 1 mm, and when the wire rods of the coil springs 144 come into contact with each other by twisting in order to prevent excessive twisting of the coil spring 144, the end surface 146j and the end surface 136k Are set to contact each other.
  • a rib (not shown) is provided on the outer surface of the convex portion 146h along the axial direction, and the rib is received in the through hole 136j and moved within a predetermined range. You may provide the recess which does not illustrate which regulates.
  • FIG. 4 is a partial sectional view of a coil spring 244 showing another modification of the coil spring.
  • FIG. 4 shows a state where the coil spring 244 is screwed to the rotating shaft 236.
  • the spiral grooves 236f of the rotation shaft 236 are separated from each other by a wall 238 at a predetermined pitch.
  • the portion of the coil spring 244 corresponding to the spiral groove 236f is also spaced at a predetermined pitch, and when it is screwed to the rotating shaft 236, the configuration shown in FIG.
  • FIG. 5 shows a cutting blade side transmission shaft 6 a in which a spring mounting portion 46 is attached to the transmission long portion 20. Since the cutting blade side transmission shaft 6a is long, it is partially omitted in the figure.
  • the cutting blade side transmission shaft 6a is formed on a transmission elongated portion 20 composed of an elongated pipe having an inner diameter and an outer diameter of about 1.3 to 1.5 m that are uniform in the axial direction, and at both ends of the transmission elongated portion 20. Male splines 20a and 20b.
  • the spline 20 a is inserted into the female spline groove 46 a of the spring mounting portion 146, and the spline 20 b is inserted into a female spline groove (not shown) of the cutting blade unit 3.
  • the existing cutting blade side transmission shaft can be replaced with the cutting blade side transmission shaft 6a. That is, the existing cutting blade side transmission shaft is extracted from the bearing 5 on the prime mover 2 side, and can be easily replaced by inserting the cutting blade side transmission shaft 6a instead.
  • the spring mounting portion 46 of the cutting blade side transmission shaft 6 a constituting the vibration damping mechanism 21 is located at the end of the cutting blade side transmission shaft 6 a and may interfere with the bearing 5 when inserted into the operation rod 1. This is because there is not.
  • FIG. 6 shows the transmission shaft 106.
  • the transmission shaft 106 includes a cutting blade side transmission shaft 6 a, a rotation shaft (prime motor side transmission shaft) 66, and a coil spring 44 that couples the cutting blade side transmission shaft 6 a and the rotation shaft 66. Therefore, in this embodiment, the vibration damping mechanism 61 is configured between the rotary shaft 66 and the cutting blade side transmission shaft 6a.
  • the rotary shaft 66 is not directly fixed to the drum 34 in the centrifugal clutch case portion 8, but has a male spline 66a.
  • the spline 66a is inserted into a female spline (not shown) on the centrifugal clutch case 8 side (not shown).
  • the transmission shaft 106 including the rotating shaft 66 and the coil spring 44 can all be replaced with existing ones.
  • the vibration damping mechanism of the present invention can be provided not in the end portion of the transmission shaft 106 but in the intermediate portion when the operating rod 1 is of a type that can be divided at the intermediate portion in the longitudinal direction. It will be easy for the contractor to understand. Moreover, although it illustrated that the spring mounting part 146 and the transmission elongate part 20 were connected by the spline, it is not limited to this, You may use means, such as welding and friction welding. Moreover, the coupling
  • the spline is configured by the parallel knurl portion, but the cross section is coupled by the convex portion and the concave portion having a non-circular shape so that the two cannot be relatively rotated around the central axis. Any shape can be used.
  • the coil springs 44, 144, 244 constituting the vibration damping mechanisms 21, 61, 121 of the present invention are respectively provided with spiral grooves 36f, 136f, 236f on both the prime mover side transmission shafts 36, 66 and the cutting blade side transmission shaft 6a. In addition to being screwed into the spiral grooves 46f and 146f, it may be fixed to any one side of the transmission shaft by appropriate means.
  • a disc-shaped round blade is used as the cutting blade.
  • the cutting blade may be any blade that can cut weeds and the like by rotating. It may be composed of one or two string-like nylon cords having one end connected to the tip of the shaft 10 (FIG. 1).
  • FIG. 7 is a side view showing a partially broken vibration damping mechanism 221 of this embodiment.
  • the vibration damping mechanism 221 is basically a rotary bearing portion 236 fixed to the centrifugal clutch drum 34.
  • a prime mover side transmission shaft portion comprising a rotation shaft 251 splined thereto, a rotation shaft 252 constituting the cutting blade side transmission shaft portion, and a coil spring 253 for transmitting the rotation of the rotation shaft 251 to the rotation shaft 252 It is composed of
  • the rotary shaft 251 has a large-diameter portion 251a, a spring insertion portion 251b that projects from the large-diameter portion 251a to the opposite side of the prime mover, and a large-diameter portion 251a that faces the prime mover.
  • the base portion 251c protruding in this manner is provided.
  • the large-diameter portion 251a has an end surface 251d on the insertion portion 251b side formed in a spiral shape. Therefore, one end and the other end of the end surface 251d are discontinuous.
  • the step portion is a contact portion 251e that receives one end of the wire rod of the coil spring 253 as will be described later.
  • the spring insertion part 251b has a shape having a concave part 251f having a circular cross section at the center. Further, a male spline 251g is formed at a portion near the tip of the base 251c.
  • a circular hole 236a extending in the axial direction is formed in the center of the rotary bearing 236, and a female spline 236b is formed in the peripheral wall portion.
  • the base 251c of the rotating shaft 251 is inserted into the circular hole 236a so that the male spline 251g meshes with the female spline 236b.
  • the rotating shaft 251 rotates with the rotating bearing 236 when rotated.
  • the rotation direction of the rotary bearing 236 is the direction indicated by the arrow F in FIGS.
  • the rotary shaft 252 constituting the cutting blade side transmission shaft portion includes a large-diameter portion 252a and a spring insertion portion 252b projecting from the large-diameter portion 252a toward the prime mover. It is what you have.
  • the large-diameter portion 252a has the same shape as the large-diameter portion 251a of the rotary shaft 251 and has an end surface 252d and an abutment portion 252e similar to the spiral end surface 251d and the abutment portion 251e of the large-diameter portion 251a, respectively. is doing.
  • a cylindrical convex portion 252f that protrudes forward, that is, toward the prime mover is provided at the tip of the spring insertion portion 252b.
  • the transmission shaft 6 is fixed to the large-diameter portion 252a of the rotary shaft 252 in a coaxial state by, for example, press-fitting a tip portion into a hole drilled in the center portion or welding a part thereof. Has been.
  • the transmission shaft 6 is the same as that shown in FIG. 1 and transmits the rotation of the rotary shaft 252 to the cutting blade.
  • the rotating shaft 251 and the rotating shaft 252 are configured such that one end side and the other end side of the coil spring 253 are fitted to the spring insertion portions 251b and 252b, and then the spring insertion portions 251b. , 252b are arranged so that the front end faces thereof face each other.
  • the outer diameters of the spring insertion portions 251b and 252b are, for example, about 6.5 mm, but the inner diameter of the coil spring 253 is slightly larger than that, so that the coil spring 253 is smaller than the spring insertion portions 251b and 252b. The relative rotation is possible.
  • the coil spring 253 has a coil portion close to one end of the wire 253a along the spiral end surface 251d of the rotating shaft 251 and a coil portion close to the other end of the wire 253a along the spiral end surface 252d of the rotating shaft 252. It will be in contact.
  • the total length of the coil spring 253 is such that when the above state is reached, a slight gap is generated between the tip end surfaces of the spring insertion portions 251b and 252b so that they can rotate relative to each other. .
  • the coil spring 253 may be formed in a state where there is a slight gap between adjacent wire rods (ring portions), or may be formed in a state where there is no such gap, In the embodiment, the latter state is assumed.
  • the columnar convex portion 252f of the rotary shaft 252 is accommodated in the concave portion 251f formed on the rotary shaft 251.
  • the outer diameter of the cylindrical convex portion 252f is about 4.0 mm, for example, but the inner diameter of the concave portion 251f of the rotating shaft 251 is slightly larger than that, so that the cylindrical convex portion 252f is within the concave portion 251f. Relative rotation with respect to the rotation shaft 251 is possible.
  • a sleeve 261 is provided to cover the entire length of the coil spring 253 arranged as described above at a predetermined interval from the outer periphery.
  • the sleeve 261 has a cylindrical portion 261a and a bottom portion 261b formed on one end side thereof.
  • a circular hole 261c having an inner diameter larger than the outer diameter of the transmission shaft 6 is formed at the center of the bottom 261b.
  • the sleeve 261 is disposed in a state in which the transmission shaft 6 passes through the circular hole 261c, and the cylindrical portion 261a is located on the outer periphery of the large diameter portions 251a and 252a and the coil spring 253 so as to be rotatable relative thereto.
  • a female thread is formed on the outer peripheral surface of the end of the cylindrical portion 261a, that is, the end opposite to the bottom 261b, and a cylindrical cap 262 with a bottom is screwed to the sleeve 261 so that the sleeve 261 is connected to the transmission shaft 6. The movement to the right in FIG. 7 is prevented.
  • a circular hole 262a having an inner diameter larger than the outer diameter of the base 251c of the rotating shaft 251 is formed at the center of the cap 262, and the base 251c passes through the circular hole 262a.
  • An annular rubber washer 263 that functions as a spacer for preventing the sleeve 261 from moving in the axial direction is disposed between the end surface of the large-diameter portion 251a of the rotating shaft 251 and the cap 262.
  • the sleeve 261 may have a shape including only the cylindrical portion 261a without the bottom 261b, and the cap 262 may be screwed to both one end and the other end.
  • the rotation transmission from the motor-side rotating shaft 251 to the cutting blade-side rotating shaft 252 is performed via the coil spring 253, so that the vibration shown in FIG. 2A and FIG. A vibration buffering action is obtained basically in the same manner as in the buffer mechanisms 21 and 121.
  • the vibration buffer mechanism of the present embodiment has a very simple structure. Further, it is not necessary to firmly fix each end of the coil spring 253, the rotary shaft 251, and the rotary shaft 252 by means such as press-fitting or screwing. Therefore, also from these points, the vibration damping mechanism of the present embodiment can be sufficiently reduced in size and cost, and can be easily assembled and disassembled.
  • the coil spring 253 is pushed and rotated as described above, that is, the rotation is transmitted by applying a force in the compression direction to the wire of the coil spring 253.
  • the coil spring 253 is elastically deformed so as to increase its diameter and performs a buffering action.
  • the coil spring 253 is deformed too much, there is a possibility that the ring portion of the expanded spring will be exposed and a situation may occur in which the coil spring 253 rides on the adjacent ring portion.
  • the sleeve 261 as described above is provided. That is, when the sleeve 261 is disposed, the diameter of the ring portion of the coil spring 253 is restricted by the sleeve 261, so that the coil spring 253 is not greatly deformed, and the above-described undesirable situation occurs. Can be surely prevented.
  • the coil spring 253 expands in diameter and cannot perform a buffering action. Therefore, the sleeve 261 is sure to generate this space. It is necessary to set the inner diameter and the outer diameter of the coil spring 253. Specifically, for example, when the outer diameter of the coil spring 253 is about 12.0 mm, the interval is preferably about 0.1 mm.
  • the columnar convex portion 252f of the rotating shaft 252 is housed in the concave portion 251f formed on the rotating shaft 251, so that the columnar convex portion 146h is a through-hole as shown in FIG.
  • the coaxiality between the rotating shaft 251 and the rotating shaft 252 is ensured, and the effect of reducing vibration is obtained.
  • FIG. 10 is a partially cutaway side view showing the vibration damping mechanism 321 of this embodiment.
  • the vibration damping mechanism 321 is compared with the vibration damping mechanism 221 shown in FIG.
  • the structure of the sleeve arranged on the outer periphery is different, and the other points are basically formed in the same manner as the vibration damping mechanism 221.
  • a sleeve 361 including a bottom portion 361b having a circular hole 361c at the center and a cylindrical portion 361a is used, and the tip portion of the cylindrical portion 361a is shaped to receive the push nut 301. ing. Then, after the sleeve 361 is disposed in a state where the cylindrical portion 361a is provided on the outer periphery of the large diameter portions 251a and 252a and the coil spring 253, the push nut 301 is assembled, whereby the sleeve 361 is attached to the coil spring 253. It is held in a state where it cannot move in the axial direction.
  • FIG. 11 is a side view showing a part of the vibration damping mechanism 421 according to the present embodiment
  • FIG. 12 is an exploded perspective view showing a part of the vibration damping mechanism 421.
  • the vibration damping mechanism 421 of the present embodiment is different from the vibration damping mechanism 221 shown in FIG. 7 in the structure of the sleeve arranged on the outer periphery of the coil spring 253, and the other points are basically the above-described vibration damping mechanism. It is formed similarly to the mechanism 221.
  • a sleeve 461 consisting only of a cylindrical portion is used, and this sleeve 461 is disposed so as to be located on the outer periphery of the large-diameter portions 251a and 252a and the coil spring 253.
  • a mounting hole 252j that penetrates in the radial direction is formed in the large-diameter portion 252a of the rotating shaft 252, and two circular holes 461a and 461a that are aligned with one end and the other end of the mounting hole 252j are formed in the sleeve 461.
  • a substantially cylindrical pin 462 passed through one circular hole 461a is passed through the mounting hole 252j of the large diameter portion 252 and protrudes from the other circular hole 461a, and then a circle is formed in the vicinity of one end and the other end of the pin 462.
  • the snap pins 463 By attaching the snap pins 463 to pin grooves (not shown) formed in an annular shape, the sleeve 461 is integrated with the large diameter portion 252a of the rotating shaft 252 via the pins 462.
  • a mounting hole 251j that penetrates in the radial direction is also formed in the large-diameter portion 251a of the rotary shaft 251, while the sleeve 461 has two long holes 461b and a long hole 461b facing one end and the other end of the mounting hole 251j. Is formed. Further, the two collars 464 and 464 are arranged on the sleeve 461 so as to cover the long hole 461b and the long hole 461b. Each collar 464 is formed with a circular hole 464a.
  • a substantially cylindrical pin 465 passed through the circular hole 464a of one collar 464 is passed through one long hole 461b of the sleeve 461, the circular hole 251j of the large diameter portion 251a, and the other long hole 461b of the sleeve 461, The other collar 464 protrudes from the circular hole 464a.
  • the sleeve 461 is attached to the large-diameter portion 251a of the rotary shaft 251 via the pin 465. Assembled.
  • the sleeve 461 is assembled in a state in which the sleeve 461 is not movable in the axial direction with respect to the rotation shafts 251 and 252 and is relatively rotatable with respect to the rotation shaft 251. If the sleeve 461 can rotate relative to the rotation shaft 251 as described above, the rotation between the rotation shaft 252 and the rotation shaft 251 fixed to the sleeve 461 is allowed. Therefore, the coil spring 253 interposed between the two rotary shafts 251 and 252 can be deformed as described above, and the same buffering action as in the above-described embodiment can be obtained.
  • FIG. 13 is a side view showing the vibration damping mechanism 521 of the present embodiment in a partially broken view
  • FIG. 14 is a cross-sectional view showing an enlarged main part thereof.
  • the vibration damping mechanism 521 of the present embodiment is different from the vibration damping mechanism 221 shown in FIG. 7 in that the structure for holding the sleeve arranged on the outer periphery of the coil spring 253 is different. It is formed similarly to the vibration buffer mechanism 221.
  • a sleeve 261A composed of a cylindrical portion 261a and a bottom portion 261b similar to that shown in FIG. 7 is used, but in a portion near the tip of the cylindrical portion 261a as shown in detail in FIG.
  • An annular claw receiving groove 261e is formed on the outer peripheral surface.
  • the cap 562 combined with the sleeve 261A has a bottomed cylindrical body 562b having a circular hole 562a through which the base 251c of the rotating shaft 251 passes, and, for example, about six protruding from the tip side (right side in the drawing).
  • the engaging portion 562c is used.
  • an engaging claw 562d having a mountain-shaped cross section is provided on the inner end of each engaging portion 562c.
  • the bottomed cylindrical body 562b and the engaging portion 562c are integrally formed using, for example, steel having elasticity.
  • the cap 562 having the above-described configuration is disposed in a state where the sleeve 261A houses the large-diameter portions 251a and 252a and the coil spring 253, and is then pushed into the tip of the sleeve 261A from the engagement portion 562c side. Then, each engaging portion 562c is elastically deformed outward, and its engaging claw 562d rides on the outer peripheral surface of the cylindrical portion 261a of the sleeve 261A. When the cap 562 is pushed in as it is, each engaging claw 562d is cylindrical. The state shown in FIG. 14 is obtained by engaging with the claw receiving groove 261e of the portion 261a. Thus, the sleeve 261A and the cap 562 are integrated, and the rotation shaft 251 and the rotation shaft 252 are prevented from being separated from each other.
  • the claw receiving groove 261e of the cylindrical portion 261a is a single annular groove, but instead, for example, six short claws for receiving each of the six engaging claws 562d.
  • a nail receiving groove may be formed.
  • FIG. 15 is a side view showing the vibration damping mechanism 621 of this embodiment with a part thereof broken.
  • the vibration buffer mechanism 621 of the present embodiment is different from the vibration buffer mechanism 221 shown in FIG. 7 in that rotational shafts 251A and 252A having slightly different structures from the rotational shafts 251 and 252 are used. Other points are basically the same as those of the vibration damping mechanism 221.
  • the rotary shaft 251A used in the present embodiment has a shape obtained by removing the spring insertion portion 251b from the rotary shaft 251 shown in FIG. 7, and similarly, the rotary shaft 252A is also the rotary shaft shown in FIG. The spring insertion portion 252b is removed from the shape 252. And the coil spring 253 is arrange
  • the coil spring 253 is not held by the spring insertion portion 251b and the insertion portion 252b, but instead is held by the sleeve 261 from the periphery, and therefore moves to the outer periphery to move to the large diameter portions 251a and 252a. It is prevented from falling out of the space.
  • the spring insertion portion is not provided on the two rotating shafts, it is always necessary to provide a sleeve.
  • the rotary shaft 252 that is the cutting blade side transmission shaft portion of the vibration damping mechanisms 221, 321, 421, 521, and 621 of each embodiment described above is also combined with the transmission long portion 20 as shown in FIG.
  • the cutting blade side transmission shaft can be configured.
  • a drum assembly can be constructed.
  • the transmission shaft of the brush cutter can be configured by combining the vibration damping mechanisms 221, 321, 421, 521, and 621 of the above embodiments and the transmission long portion 20.

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Abstract

La présente invention concerne un mécanisme amortisseur de vibrations pour tondeuse, un arbre de transmission de puissance situé côté lames de coupe, un arbre de transmission de puissance et un ensemble tambour d'embrayage centrifuge. Le mécanisme amortisseur de vibrations réduit à la fois les vibrations de torsion et les vibrations de flexion de l'arbre de transmission de puissance, est constitué d'un nombre réduit de pièces, est de structure simple, facile à assembler et peu coûteux. L'invention concerne donc un mécanisme amortisseur de vibrations (121) pour tondeuse qui comprend une partie arbre de transmission de puissance située côté moteur (136) et reliée à celui-ci, et dans la périphérie de laquelle est façonnée une rainure hélicoïdale (136f), une partie arbre de transmission de puissance située côté lames de coupe (6a) et reliée à l'une de celles-ci, et dans la périphérie de laquelle est façonnée une rainure hélicoïdale (146f), séparée de la rainure hélicoïdale (136f) de la partie arbre de transmission de puissance située côté moteur (136), et un ressort enroulé (144) comportant un côté terminal inséré dans la rainure hélicoïdale (136f), son autre côté terminal étant inséré dans la rainure hélicoïdale (146f), un espacement prédéterminé (Sa) étant prévu entre les parties annulaires de la partie du ressort enroulé qui n'est pas insérée dans les rainures hélicoïdales (136f, 146f). La rotation de la partie arbre de transmission de puissance située côté moteur (136) est transmise à la partie arbre de transmission de puissance située côté lames de coupe (6a) par l'intermédiaire du ressort enroulé (144).
PCT/JP2009/002591 2008-06-11 2009-06-09 Mécanisme amortisseur de vibrations pour tondeuse, arbre de transmission de puissance situé côté lames de coupe, arbre de transmission de puissance et ensemble tambour d'embrayage centrifuge WO2009150823A1 (fr)

Applications Claiming Priority (4)

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JP2008-152727 2008-06-11
JP2008152727 2008-06-11
JP2009021083A JP5265402B2 (ja) 2008-06-11 2009-02-02 刈払機の振動緩衝機構、刈刃側伝動軸、伝動軸および遠心クラッチドラム組立体
JP2009-021083 2009-02-02

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JP2012110308A (ja) * 2010-11-29 2012-06-14 Yamada Kikai Kogyo Kk 捩じり振動吸収装置、およびこれを備えた携帯型動力刈払機
JP5250083B2 (ja) * 2011-06-22 2013-07-31 株式会社岡山農栄社 携帯型刈払機
KR101330881B1 (ko) 2011-12-26 2013-11-18 계양전기 주식회사 예초기
JP7178255B2 (ja) * 2018-12-21 2022-11-25 三菱重工メイキエンジン株式会社 刈払機の回転力伝達装置および刈払機

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49143306U (fr) * 1973-04-11 1974-12-11
JPS5691928U (fr) * 1979-12-19 1981-07-22
JP2005168339A (ja) * 2003-12-09 2005-06-30 Komatsu Zenoah Co 携帯型作業機
JP2007061029A (ja) * 2005-09-01 2007-03-15 Kioritz Corp 振動吸収継手及びそれを備えた携帯型刈払機

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49143306U (fr) * 1973-04-11 1974-12-11
JPS5691928U (fr) * 1979-12-19 1981-07-22
JP2005168339A (ja) * 2003-12-09 2005-06-30 Komatsu Zenoah Co 携帯型作業機
JP2007061029A (ja) * 2005-09-01 2007-03-15 Kioritz Corp 振動吸収継手及びそれを備えた携帯型刈払機

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