JP2015073482A - Power transmission device and gardening clipper employing power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibration and gear noise from a gear pair formed by a drive gear driving by receiving driving force of a motor of a power transmission device and one or more driven gears rotatably supported by support shafts.SOLUTION: A power transmission device 20 for a gardening clipper 10 includes: a drive gear 21 driving by receiving driving force of a motor 13; and driven gears 23a, 23b, and 25 that are rotatably supported by support shafts 22 and 24 fixed to fitting parts 11a and 11c of a housing 11. The drive gear 21 and the driven gears 23a, 23b, and 25 form two sets of gear pairs and transmit the drive force of the motor 13 to driven members 31 and 32 via a crank cam 27. The support shaft 22 is fixed to the fitting part 11a via a vibration-proof member 26 consisting of a soft and elastic member.

Description

  The present invention relates to a power transmission mechanism for transmitting a driving force of a prime mover and a gardening hair clipper such as a hedge trimmer and a lawn hair clipper employing the power transmission mechanism.

  Patent Document 1 discloses a gardening hair clipper. This gardening hair clipper is provided with an electric motor provided inside the housing, a power transmission mechanism for transmitting the driving force of the electric motor to a pair of upper and lower shear blades, and protruding forward at the bottom of the housing. And a pair of upper and lower blades that reciprocate in the opposite directions in the front-rear direction.

  In this gardening hair clipper, the power transmission mechanism forms a gear pair by a pinion gear fixed to the drive shaft of the electric motor and an upper gear of a two-stage gear rotatably supported by a first support shaft fixed to the lower part of the housing. A gear pair is formed by the lower gear of the two-stage gear and the final gear rotatably supported by a second support shaft fixed to the lower portion of the housing. A crank cam that converts rotational driving by the electric motor into reciprocating motions in opposite directions in the front-rear direction of the pair of upper and lower shear blades is fixed to the final gear.

  When the electric motor of this gardening hair clipper is operated, the pinion gear is rotated by receiving the driving force of the electric motor, the two-stage gear and the final gear are rotated by the rotating pinion gear, and a pair of upper and lower is rotated by a crank cam fixed to the final gear. The blades reciprocate relatively, and the blades or lawn of the hedges are cut off by hitting the blades reciprocally moving against the hedges or grass.

Japanese Patent No. 5269715

  In the gardening hair clipper disclosed in Patent Document 1, the driving force of the electric motor is reduced to an appropriate speed by a power transmission mechanism and then transmitted to a pair of upper and lower shear blades. However, each gear used in the power transmission mechanism is often made of a resin molded product for weight reduction and cost reduction, and the accuracy of the tooth portion cannot be increased. Therefore, when the gear pair is engaged, vibration and gear sound are generated from the gear pair, and the operator may feel uncomfortable due to the vibration and gear sound. An object of the present invention is to reduce vibration and gear noise from a gear pair of a power transmission mechanism that transmits rotational drive of an electric motor.

  In order to solve the above-mentioned problems, the present invention provides a drive gear provided in a housing and driven by receiving a driving force of a prime mover, one or more support shafts fixed to a mounting portion provided in the housing, and one One or more driven gears rotatably supported by the above support shafts, and one or more pairs of gears are formed by the drive gear and the one or more driven gears, and the driving force of the prime mover is applied to the driven member. A power transmission mechanism that transmits power, wherein the support shaft is fixed to the mounting portion via a vibration isolation member made of a flexible elastic member.

  In the power transmission mechanism configured as described above, since the support shaft is fixed to the mounting portion via a vibration isolation member made of a flexible elastic member, even if there is a slight misalignment of the gear pair, the engagement of the gear pair Can be absorbed by the vibration isolating member around the support shaft, and the generation of vibration and gear noise caused by the gear pair meshing shift can be suppressed.

  In the power transmission mechanism configured as described above, it is preferable to employ a rubber O-ring as the vibration isolating member. In this case, the work of attaching the vibration isolating member to the support shaft is facilitated. In the power transmission mechanism configured as described above, it is preferable that the support shaft is fixed to the attachment portion via the vibration isolation member on both the upper and lower sides of the driven gear.

  Also, a crank cam fixed to the output transmission gear of the power transmission mechanism configured as described above, and a pair of upper and lower parts that protrude forward from the bottom of the housing and relatively reciprocate in the horizontal direction by the crank cam. As described above, in the gardening hair clipper provided with the blade of this type as a driven member, it is possible to suppress the generation of vibrations and gear sounds resulting from the shifting of the gear pair meshing, and the work of the operator using the gardening hair clipper The environment has been improved.

It is a perspective view of the hedge trimmer which is one embodiment of the gardening hair clipper which employs the power transmission mechanism of the present invention. FIG. 2 is a longitudinal cross-sectional view along the front-rear direction of the power transmission mechanism housed in the lower portion of the housing with the right side portion of the housing of FIG. 1 removed. It is a partially expanded sectional view of FIG. It is other embodiment of a power transmission mechanism, and is a partially expanded sectional view equivalent to FIG.

  Hereinafter, a hedge trimmer which is an embodiment of a gardening hair clipper employing a power transmission mechanism of the present invention will be described with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the hedge trimmer 10 includes an electric motor (prime mover) 13 in a housing 11 integrally provided with a grip 12 gripped by an operator at a rear portion, and an electric motor in a lower portion in the housing 11. 13 has a power transmission mechanism 20 for transmitting 13 driving forces to a pair of shear blades (driven members, blades) 31 and 32, and a pair of upper and lower shear blades 31 and 32 provided to protrude forward at the bottom of the housing 11. And a blade assembly 30.

  The lower portion of the housing 11 is provided with first and second support shaft mounting portions 11a and 11c to which upper ends of first and second support shafts 22 and 24 constituting a power transmission mechanism 20 described later are fixed. The first and second support shaft mounting portions 11a and 11c are substantially cylindrical holes opened downward. Further, an annular groove 11b is formed in the middle portion in the vertical direction on the inner peripheral surface of the first support shaft attaching portion 11a, and this annular groove 11b is for accommodating a vibration isolating member 26 described later.

  The power transmission mechanism 20 transmits the driving force of the electric motor 13 to a pair of upper and lower shear blades 31 and 32. In this embodiment, the power transmission mechanism 20 decelerates the driving force of the electric motor 13 by the driving gear 21 and the driven gears 23a, 23b and 25, and reciprocates the rotational drive by the crank cam 27 fixed to the driven gear 25 on the output side. Is transmitted to a pair of upper and lower shear blades 31, 32.

  The power transmission mechanism 20 includes a drive gear 21 formed of a pinion gear fixed to the drive shaft 13 a of the electric motor 13, a first support shaft 22 fixed to the lower portion of the housing 11, and a first support shaft 22 rotatably supported by the first support shaft 22. A second gear 23 composed of first and second driven gears 23 a and 23 b, a second support shaft 24 fixed to the lower portion of the housing 11, and a third driven gear rotatably supported by the second support shaft 24 (on the output side) Driven gear) 25.

  An annular groove 22a is formed in the upper part of the first support shaft 22, and a vibration isolating member 26 made of a flexible elastic member is attached to the position where the annular groove 22a of the first support shaft 22 is formed. The vibration isolation member 26 is made of a rubber O-ring, and is positioned so as not to move in the axial direction of the first support shaft 22 by the annular groove 22a. The upper end portion of the first support shaft 22 is fixed to the first support shaft mounting portion 11 a of the housing 11 via a vibration isolation member 26 while being prevented from rotating. At this time, the vibration isolation member 26 is accommodated in a slightly compressed state in the annular groove 11b of the first support shaft attachment portion 11a, and the first support shaft 22 is in contact with the inner peripheral surface of the first support shaft attachment portion 11a. A slight gap is formed between them. The lower end portion of the first support shaft 22 is fitted and attached with a slight clearance in a first mounting hole 34a formed in the lower guide plate 34 that constitutes the bottom wall of the housing 11. It has been.

  A two-stage gear 23 is rotatably supported at an intermediate portion of the first support shaft 22 in the axial direction, and the two-stage gear 23 includes an upper first driven gear 23a and a lower second driven gear 23b. The two-stage gear 23 is formed by injection molding a resin member such as nylon. The upper first driven gear 23 a of the two-stage gear 23 is engaged with the drive gear 21 of the electric motor 13.

  The upper end portion of the second support shaft 24 is fixed in a state in which it is prevented from rotating on the second support shaft mounting portion 11c of the housing 11 described above. A lower portion of the second support shaft 24 is fitted and attached to a second mounting hole 34b formed in the lower guide plate 34 of the blade assembly 30 with a slight clearance.

  A driven gear 25 is rotatably supported on the second support shaft 24. The driven gear 25 is formed by injection molding a resin member such as nylon. The driven gear 25 is engaged with the lower driven gear 23 b of the two-stage gear 23. The driven gear 25 is a driven gear on the output side of the power transmission mechanism 20. Each of the driven gears 23a, 23b and 25 has a greater number of teeth than the drive gear 21 and the driven gear 23b has a larger number of teeth than the driven gear 25 in order to decelerate the rotational drive of the electric motor 13. ing.

  A crank cam 27 is detachably fixed to the lower surface of the driven gear 25, and the crank cam 27 converts a rotational drive by the electric motor 13 into a reciprocating motion of the pair of upper and lower blades 31, 32 in the front-rear direction. The crank cam 27 is composed of a pair of upper and lower disks 27a and 27b arranged eccentrically with respect to the second support shaft 24, and is fixed to the lower surface of the driven gear 25 by two pins. Both discs 27a, 27b are arranged at positions facing each other across the second support shaft 24, that is, having a phase difference of 180 °.

  The blade assembly 30 is detachably fixed to the bottom of the housing 11. The blade assembly 30 includes a pair of upper and lower shear blades 31 and 32 and guide plates 33 and 34 that hold the pair of shear blades 31 and 32 so as to be slidable in the front-rear direction from both upper and lower sides. The pair of shear blades 31, 32 extend long in front of the housing 11, and the shear blades 31, 32 have a plurality of blade portions formed in a comb shape on both sides in the longitudinal direction. Engagement holes 31a and 32a that are long and rounded rectangular in the lateral direction are formed at the base ends of the shear blades 31 and 32, and discs 27a and 27b of the crank cam 27 are formed in the engagement holes 31a and 32a. The holes 31a and 32a are fitted so as to be movable in the longitudinal direction. The lower guide plate 34 is detachably fixed to each corner of the bottom portion of the housing 11 with screws so that the base end portion forms the bottom wall of the housing 11 and covers the power transmission mechanism 20.

  The operation of the hedge trimmer 10 configured as described above will be described. When the electric motor 13 is driven to rotate, the driving force of the electric motor 13 is transmitted to the pair of shear blades 31 and 32 by the power transmission mechanism 20. More specifically, when the driving gear 21 is driven to rotate by receiving the driving force of the electric motor 13, the first driven gear 23a that forms a gear pair with the driving gear 21 rotates. The second driven gear 23b rotates integrally with the first driven gear 23a, and the third driven gear 25 forming a gear pair with the first driven gear 23a rotates. Thus, the driving force of the electric motor 13 is transmitted to the third driven gear 25 in a state where the driving force is decelerated by the two pairs of gears.

  As the third driven gear 25 rotates, the disks 27 a and 27 b of the crank cam 27 revolve around the second support shaft 24. As each disk 27a, 27b slides and moves along the longitudinal direction of the engagement holes 31a, 32a of the shear blades 31, 32, the shear blades 31, 32 reciprocate in opposite directions in the front-rear direction. As described above, the rotational drive transmitted by receiving the driving force of the electric motor 13 is converted by the crank cam 27 into the reciprocating motions of the pair of shear blades 31 and 32 that are opposite to each other and transmitted. In this state, the blades of the hedge are cut by applying the shear blades 31, 32 to the branches of the hedge.

  In the power transmission mechanism 20 of the hedge trimmer 10 configured as described above, a gear pair composed of the drive gear 21 and the first driven gear 23a of the second gear 23, or the second driven gear 23b and the third driven gear of the second gear 23. There is a possibility that a slight misalignment of the gear pair with the gear 25 may occur. In particular, since the two-stage gear 23 and the third driven gear 25 are molded products made of a resin member, a slight misalignment tends to occur between the gear pairs.

  In the power transmission mechanism 20 used in the hedge trimmer 10, the upper end portion of the first support shaft 22 that rotatably supports the two-stage gear 23 is arranged at the first lower portion of the housing 11 via a vibration isolating member 26 made of an O-ring. It is fixed to the support shaft mounting portion 11a. As a result, when the rotational drive by the electric motor 13 is transmitted to the pair of shear blades 31 and 32 by the power transmission mechanism 20, even if there is a slight misalignment of the gear pair, the first misalignment of the gear pair is detected. The vibration isolating member 26 around the support shaft 22 can absorb the vibration, and the generation of the vibration and the gear sound caused by the shift of the meshing of the gear pair can be suppressed.

  Further, as shown in FIG. 4, a cylindrical first support shaft attachment portion 11d for attaching the lower portion of the first support shaft 22 to the lower portion of the housing 11 is further provided, and the lower portion of the first support shaft 22 is formed by an O-ring. You may make it attach to the 1st support shaft attaching part 11d via the vibration isolator 28 which becomes. Also in this case, the vibration isolating member 28 is accommodated in a slightly compressed state in the annular groove 11e in the first support shaft attachment portion 11d, and the first support shaft 22 is accommodated in the first support shaft attachment portion 11d. A slight gap is formed between the peripheral surface. In this case, the first support shaft 22 can be fixed to the mounting portions 11a and 11d of the housing 11 via the vibration isolation members 26 and 28 on both the upper and lower sides of the two-stage gear 23, and the gear pair Can be more effectively absorbed by the vibration isolating members 26 and 28 around the first support shaft 22, and the generation of vibration and gear noise caused by the gear pair disengagement can be suppressed.

  In the embodiment described above, the power transmission mechanism 20 has been described as being used in the garden trimmer hedge trimmer 10, but the present invention is not limited to this, and the driving force of the prime mover uses one or more pairs of gears. Thus, the power transmission mechanism 20 of the present invention can also be employed as a working machine for transmitting to the driven member, such as a gardening work machine such as a brush cutter or a chainsaw, an electric drill, an impact wrench or the like.

  In the above-described embodiment, the electric motor 13 is used as the prime mover. However, the present invention is not limited to this, and the same effect can be obtained even if an engine is used as the prime mover.

  In the embodiment described above, the power transmission mechanism 20 transmits the rotational drive of the electric motor 13 by decelerating using a gear pair. However, the present invention is not limited to this, and the rotational drive of the electric motor 13 is performed. May be transmitted at a speed increased by the gear pair, or may be transmitted by the gear pair without changing the speed of the rotational drive of the electric motor 13.

  In the embodiment described above, the power transmission mechanism 20 transmits the rotational drive of the electric motor 13 by decelerating in two stages by two pairs of gears, but the present invention is not limited to this, and the first The crank cam 27 may be fixed to the lower surface of the driven gear 23a, and the rotational drive of the electric motor 13 may be decelerated and transmitted in one stage. Furthermore, one or more pairs of gears may be added to the power transmission mechanism 20 so that the rotational drive of the electric motor 13 is decelerated and transmitted in three or more stages. In this case, the gears are rotatably supported. The appropriate support shaft may be attached to the attachment portion of the housing 11 via the vibration isolation member.

  In the embodiment described above, the first support shaft 22 is fixed to the mounting portion of the housing 11 via the vibration isolation member 26 (26 and 28). However, the present invention is not limited to this, and the second support shaft 24 is not limited thereto. At least one of the upper part and the lower part may be fixed to the housing 11 via a vibration isolating member, and the same effects as described above can be obtained also in this case.

  In the above-described embodiment, the O-rings are used for the vibration isolation members 26 and 28. However, the present invention is not limited to this, and the support shaft is provided on a rubber cylinder (sleeve shape) or a rubber plate. Even if a vibration isolating member having a through-hole to be inserted is used, the same effect can be obtained.

  The embodiment described above describes the hedge trimmer that cuts branches and leaves of hedges, but the gardening hair clipper of the present invention is a lawn hair clipper that reciprocally moves a pair of cutting blades (blades) in the left-right direction via a crank cam. Also applies.

  In the above-described embodiment, the two discs 27a and 27b of the crank cam 27 are engaged with the engaging holes 31a and 32a of the pair of upper and lower shear blades 31 and 32, whereby both the shear blades 31 and 32 are moved in the front-rear direction. Are reciprocated in opposite directions. However, the present invention is not limited to this, one shear blade is fixed so as not to reciprocate, the other shear blade is reciprocated in the front-rear direction, and a pair of upper and lower shear blades are relatively moved in the front-rear direction. It is also applied to a single-edge driven hedge trimmer that reciprocates.

 DESCRIPTION OF SYMBOLS 10 ... Horticultural hair clipper (hedge trimmer), 11 ... Housing, 11a ... Attachment part (1st support shaft attachment part), 11c ... Attachment part (2nd support shaft attachment part), 11d ... Attachment part (1st support shaft attachment part) ), 13 ... prime mover (electric motor), 20 ... power transmission mechanism, 21 ... drive gear, 22 ... support shaft (first support shaft), 23a ... driven gear (first driven gear), 23b ... driven gear (second) (Driven gear), 24 ... support shaft (second support shaft) 25 ... driven gear (third driven gear), 26, 28 ... vibration isolation member, 27 ... crank cam, 31, 32 ... blade (shear blade).

Claims (4)

A drive gear provided in the housing and driven by the driving force of the prime mover;
One or more support shafts fixed to a mounting portion provided in the housing;
One or more driven gears rotatably supported on the one or more support shafts;
A power transmission mechanism that forms one or more pairs of gears by the drive gear and the one or more driven gears to transmit the driving force of the prime mover to a driven member;
The power transmission mechanism, wherein the support shaft is fixed to the mounting portion via a vibration isolating member made of a flexible elastic member. The power transmission mechanism according to claim 1,
A horticultural hair clipper using a rubber O-ring as the vibration-proof member. The power transmission mechanism according to claim 1 or 2,
A horticultural hair clipper, wherein the support shaft is fixed to the mounting portion via the vibration isolation member on both the upper and lower sides of the driven gear. A gardening hair clipper employing the power transmission mechanism according to any one of claims 1 to 3,
The power transmission mechanism further includes a crank cam fixed to the driven gear on the output side,
A horticultural hair clipper provided with a pair of upper and lower blades protruding forward at the bottom of the housing and reciprocally moved in the horizontal direction by the crank cam as the driven member.

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