JP2014233778A - Work machine with reciprocal movement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent efficiency reduction in work using a work machine with reciprocal movement.SOLUTION: A hedge trimmer 1 with reciprocally driven blades 3a, 3b comprises: a reversely rotatable electric motor 10; a conversion mechanism for converting rotational driving force outputted from the electric motor 10 to reciprocal driving force to reciprocate the blades 3a, 3b; a first driving force transmission path provided between the electric motor 10 and the conversion mechanism and inputting the rotational driving force to the conversion mechanism during normal rotation of the electric motor 10; a second driving force transmission path for inputting the rotational driving force to the conversion mechanism during reverse rotation of the electric motor 10; a first speed reduction mechanism provided in the first driving force transmission path; and a second speed reduction mechanism provided in the second driving force transmission path and having a different speed reduction ratio from the first speed reduction mechanism. The rotation direction of the rotational driving force inputted to the conversion mechanism through the first driving force transmission path is opposite to the rotation direction of the rotational driving force inputted to the conversion mechanism through the second driving force transmission path.

Description

  The present invention relates to a reciprocating machine having a working tool that is driven to reciprocate.

  Various reciprocating machines equipped with reciprocating working tools are known, and a trimming machine (hereinafter referred to as “hedge trimmer”) is one example. A general hedge trimmer is a motor as a driving source, a conversion mechanism that converts a rotational driving force output from the motor into a reciprocating driving force, and a working tool that is driven back and forth by a reciprocating driving force output from the conversion mechanism. A blade, and is used for pruning work of branches and leaves.

  Here, when cutting a thick branch or a hard branch with a hedge trimmer, the blade may bite into the branch and stop. That is, the motor may be locked. Therefore, prior to pruning work using a hedge trimmer, it is recommended to cut thick branches and hard branches and leaves in advance by pruning, sawing, or the like.

JP 2012-176464 A

  However, the blade of the hedge trimmer may bite into the branches and leaves for various reasons. When the blade bites into the branches and leaves, it is not easy to release the bite, and it takes a lot of time and effort. Specifically, it is necessary to temporarily suspend the work, hold the hedge trimmer with one hand, grasp the branches and leaves in which the blade is biting with the other hand, and pull the hedge trimmer away from the branches and leaves. Alternatively, it is necessary to temporarily suspend the work and twist or pull the hedge trimmer with respect to the branches and leaves. That is, if the blade of the hedge trimmer is bitten into the branches and leaves, the working efficiency is significantly reduced.

  An object of the present invention is to avoid a reduction in efficiency of work using a reciprocating machine.

  The reciprocating machine according to the present invention is a reciprocating machine having a reciprocating working tool, and a motor capable of forward and reverse rotation, and a rotational driving force output from the motor is converted into a reciprocating driving force. A conversion mechanism that reciprocates a work tool, and a first power transmission path that is provided between the motor and the conversion mechanism and that inputs a rotational driving force output from the motor to the conversion mechanism when the motor rotates forward A second power transmission path that is provided between the motor and the conversion mechanism, and that inputs a rotational driving force output from the motor to the conversion mechanism when the motor is reversely rotated, and on the first power transmission path A first speed reduction mechanism disposed on the second power transmission path, and a second speed reduction mechanism disposed on the second power transmission path and having a speed reduction ratio different from that of the first speed reduction mechanism, through the first power transmission path. Rotation drive input to the conversion mechanism And rotational direction of the rotational driving force is opposite inputted to the converting mechanism via the rotation direction and the second power transmission path of the.

  In one aspect of the present invention, the number of reduction stages of the first reduction mechanism and the second reduction mechanism is either an odd number or an even number.

  In another aspect of the present invention, the first clutch is disposed on the first power transmission path and switches between a fastening state in which the rotational driving force output from the motor is input to the conversion mechanism and a released state in which the rotational driving force is not input. And a second clutch that is disposed on the second power transmission path and switches between a fastening state in which the rotational driving force output from the motor is input to the conversion mechanism and a released state in which the rotational driving force is not input. At the time of forward rotation of the motor, the first clutch is switched to an engaged state, and the second clutch is switched to a released state. At the time of reverse rotation of the motor, the first clutch is switched to a released state, and the second clutch is Switch to the fastened state.

  According to the present invention, a decrease in efficiency of work using a reciprocating machine is avoided.

It is a perspective view of a hedge trimmer to which the present invention is applied. It is sectional drawing which shows the internal structure of the hedge trimmer shown by FIG. It is explanatory drawing which shows the structure of a 1st power transmission path. It is explanatory drawing which shows the structure of a 2nd power transmission path. It is a flowchart figure which shows an example of a control procedure.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view of a hedge trimmer as an example of a reciprocating machine to which the present invention is applied.

  A hedge trimmer 1 shown in FIG. 1 includes a housing 2 and a blade assembly 3 that protrudes forward from the front surface of the housing 2. A main handle (rear handle 4) is integrally formed at substantially the center of the housing 2, and a sub handle (front handle 5) extending upward is integrally provided near the tip of the housing 2. An operator who uses the hedge trimmer 1 holds the hedge trimmer 1 by holding the rear handle 4 with one hand and holding the front handle 5 with the other hand. A battery 6 is mounted on the back surface of the housing 2. The battery 6 can be attached to and detached from the housing 2.

  As shown in FIG. 2, an electric motor 10 that receives power supply from a battery 6 is accommodated in the housing 2. The electric motor 10 is a brushless motor that can reverse the rotation direction by electrical control. That is, the electric motor 10 is a motor capable of forward and reverse rotation. The blade assembly 3 shown in FIG. 1 includes a pair of blades 3a and 3b as work tools. The pair of blades 3a and 3b are overlapped with each other, and are linearly reciprocated in opposite directions by the driving force output from the electric motor 10 shown in FIG. That is, when the blade 3 a shown in FIG. 1 moves forward in a direction away from the housing 2, the blade 3 b moves backward in a direction approaching the housing 2. On the other hand, when the blade 3 a moves backward in the direction approaching the housing 2, the blade 3 b moves forward in a direction away from the housing 2. The drive mechanism of the blades 3a and 3b will be described in detail later.

  As shown in FIG. 2, a first switch 11 and a second switch 12 for controlling power supply to the electric motor 10 are provided inside the housing 2. Further, a circuit board 13 provided with a control circuit is accommodated in the housing 2.

  When a trigger 14 provided inside the rear handle 4 and a front trigger (not shown) provided on both side surfaces of the housing 2 are operated by an operator, the battery 6 is switched to the electric motor 10 via the circuit board 13. Electric power is supplied, the electric motor 10 is operated, and the blades 3a and 3b are linearly reciprocated as described above. Specifically, when the trigger 14 disposed below the first switch 11 is operated (when the trigger 14 is grasped together with the rear handle 4), the first switch 11 is pushed and turned ON. Further, when the front trigger is operated, the second switch 12 is pushed through the push pin 15 to be turned on. When both the first switch 11 and the second switch 12 are turned on as described above, electric power is supplied from the battery 6 to the electric motor 10 and the electric motor 10 operates.

  A switching panel 16 is provided on the upper surface of the housing 2. When the switching panel 16 is operated by the operator, the voltage applied to the electric motor 10 changes, and the rotation speed of the electric motor 10 changes. Then, the movement speed of the blades 3a and 3b increases and decreases according to the change in the rotation speed of the electric motor 10.

  As shown in FIGS. 3 and 4, an inner ring 21 a of a one-way clutch 21 as a first clutch is fixed to an output shaft of the electric motor 10 (hereinafter referred to as “drive shaft 20”). A first gear 31 is fixed to the outer ring 21b. The drive shaft 20 passes through the first gear 31, and a third gear 33 is fixed to the protruding portion of the drive shaft 20 protruding from the first gear 31.

  Next to the drive shaft 20, a rotating shaft (hereinafter referred to as “driven shaft 24”) whose both ends are rotatably supported by bearings 22 and 23 is arranged in parallel with the drive shaft 20. A second gear 32 that meshes with the first gear 31 and an inner ring 25a of a one-way clutch 25 as a second clutch are fixed to the driven shaft 24. Further, a fourth gear 34 that meshes with the third gear 33 is fixed to the outer ring 25 b of the one-way clutch 25.

  The one-way clutch 21 interposed between the drive shaft 20 and the first gear 31 is in an engaged state when the electric motor 10 is rotated forward and is released when the electric motor 10 is reversely rotated. On the other hand, the one-way clutch 25 interposed between the driven shaft 24 and the fourth gear 34 is in a released state when the electric motor 10 is normally rotated, and is in an engaged state when the electric motor 10 is reversely rotated. This will be specifically described below.

  As shown in FIG. 3, when the drive shaft 20 rotates forward as the electric motor 10 rotates forward, the inner ring 21 a and the outer ring 21 b of the one-way clutch 21 are engaged. Then, the first gear 31 fixed to the outer ring 21b of the one-way clutch 21 rotates, the second gear 32 meshed with the first gear 31 rotates, and the driven shaft 24 to which the second gear 32 is fixed is rotated. Rotate. That is, the rotational driving force output from the electric motor 10 is transmitted (input) to the driven shaft 24 via the one-way clutch 21, the first gear 31 and the second gear 32. At this time, since the third gear 33 provided on the drive shaft 20 also rotates, the fourth gear 34 meshed with the third gear 33 also rotates. However, since the one-way clutch 25 interposed between the driven shaft 24 and the fourth gear 34 is in a released state, the fourth gear 34 idles on the driven shaft 24. That is, the rotational driving force is not transmitted (input) to the driven shaft 24 via the third gear 33 and the fourth gear 34.

  As shown in FIG. 4, when the drive shaft 20 rotates in reverse with the reverse rotation of the electric motor 10, the engagement between the inner ring 21 a and the outer ring 21 b of the one-way clutch 21 is released, while the drive shaft 20 is provided. The third gear 33 and the fourth gear 34 meshing with the third gear 33 rotate. Then, the inner ring 25a and the outer ring 25b of the one-way clutch 25 are engaged, and the driven shaft 24 to which the inner ring 25a is fixed rotates. That is, the rotational driving force output from the electric motor 10 is transmitted (input) to the driven shaft 24 via the third gear 33, the fourth gear 34, and the one-way clutch 25. At this time, since the second gear 32 provided on the driven shaft 24 also rotates, the first gear 31 meshed with the second gear 32 also rotates. However, since the one-way clutch 21 interposed between the drive shaft 20 and the first gear 31 is in a released state, the first gear 31 idles on the drive shaft 20.

  As described above, during the normal rotation of the electric motor 10, the rotational driving force is transmitted through the first power transmission path constituted by the one-way clutch 21, the first gear 31 and the second gear 32. On the other hand, at the time of reverse rotation of the electric motor 10, the rotational driving force is transmitted through the second power transmission path constituted by the third gear 33, the fourth gear 34 and the one-way clutch 25.

  Here, the number of teeth of the first gear 31 shown in FIGS. 3 and 4 is smaller than the number of teeth of the second gear 32. In other words, the number of teeth of the second gear 32 is larger than the number of teeth of the first gear 31. That is, the first gear 31 is a small-diameter gear (pinion gear), the second gear 32 is a large-diameter gear (idler gear), and the two gears 31 and 32 are the first reduction gears whose number of reduction stages is one (odd number). The mechanism is configured. Further, the number of teeth of the third gear 33 is smaller than the number of teeth of the fourth gear 34. In other words, the number of teeth of the fourth gear 34 is larger than the number of teeth of the third gear 33. That is, the third gear 33 is a small-diameter gear (pinion gear), the fourth gear 34 is a large-diameter gear (idler gear), and the two gears 33 and 34 are used to reduce the number of reduction stages to one (odd number). The mechanism is configured. In short, the first power transmission path is provided with a first speed reduction mechanism, and the second power transmission path is provided with a second speed reduction mechanism.

  As described above, the drive shaft 20 provided with the first gear 31 and the third gear 33 is an output shaft in relation to the electric motor 10, but is an input shaft in relation to the speed reduction mechanism. The driven shaft 24 provided with the second gear 32 and the fourth gear 34 is an output shaft in relation to the speed reduction mechanism.

  The combination of the number of teeth of the first gear 31, the second gear 32, the third gear 33, and the fourth gear 34 shown in FIGS. 3 and 4 is such that the reduction ratio of the second reduction mechanism is less than the reduction ratio of the first reduction mechanism. Is also set to be large. That is, a speed reduction mechanism is provided in both the first power transmission path and the second power transmission path, and when the rotational driving force is transmitted through any path, the rotational speed is reduced and the rotational torque is Will be increased. However, when the rotational driving force is transmitted via the second power transmission path, the rotational speed is further reduced compared to the case where the rotational driving force is transmitted via the first power transmission path, and the rotational torque is reduced. Is further increased.

  The driven shaft 24 passes through the second gear 32 and the fourth gear 34, and the protruding portion of the driven shaft 24 protruding from the fourth gear 34 is connected to the conversion mechanism. Specifically, a cam 40 constituting a conversion mechanism is fixed to the protruding portion of the driven shaft 24. That is, the driven shaft 24 that is an output shaft in relation to the speed reduction mechanism is an input shaft in relation to the conversion mechanism.

  As shown in FIGS. 3 and 4, a first engagement portion 40 a is formed on one surface of the cam 40 fixed to the driven shaft 24 that is an input shaft of the conversion mechanism, and a second engagement is formed on the other surface. A portion 40b is formed. The cam 40 is between a first connecting member 41 that is rotatably connected to the base end of one blade 3a and a second connecting member 42 that is rotatably connected to the base end of the other blade 3b. Is arranged. Further, the first engagement portion 40 a of the cam 40 is disposed inside the engagement hole formed at one end of the first connection member 41, and the second engagement portion 40 b of the cam 40 is one end of the second connection member 42. It is arrange | positioned inside the engagement hole currently formed in this. That is, the first engaging portion 40a of the cam 40 and the base end portion of the blade 3a are rotatably connected via the first connecting member 41, and the second engaging portion 40b of the cam 40 and the base end of the blade 3b are connected. The part is connected via a second connecting member 42 so as to be rotatable. Although not shown, the two blades 3a and 3b are respectively formed with guide holes (not shown) extending in the longitudinal direction, and guides projecting from the blade guides arranged on the upper portions of the two blades 3a and 3b. A pin passes through each guide hole. Further, the first engaging portion 40a and the second engaging portion 40b of the cam 40 are 180 degrees out of phase with respect to the rotation center of the cam 40 (the central axis of the driven shaft 24). Therefore, when the cam 40 rotates with the rotation of the driven shaft 24, the two blades 3a and 3b linearly reciprocate in opposite directions along the guide by the cooperation of the guide hole and the guide pin. That is, the rotational driving force output from the electric motor 10 is converted into the reciprocating driving force, and the blades 3a and 3b are linearly reciprocated.

  As described above, the first power transmission path and the second power transmission path are provided between the electric motor 10 and the conversion mechanism. When the electric motor 10 is rotating forward, the conversion is performed via the first power transmission path. A rotational driving force is input to the mechanism (the driven shaft 24 as an input shaft) (see FIG. 3). On the other hand, during the reverse rotation of the electric motor 10, the rotational driving force is input to the conversion mechanism (the driven shaft 24 as the input shaft) via the second power transmission path (see FIG. 4). Further, the second power transmission path is provided with a second speed reduction mechanism having a larger speed reduction ratio than the first speed reduction mechanism provided in the first power transmission path. Therefore, when the rotational driving force is input to the conversion mechanism (the driven shaft 24 as the input shaft) via the second power transmission path, the conversion mechanism (the driven shaft 24 as the input shaft) is input via the first power transmission path. The driven shaft 24 rotates at a low speed and with a high torque as compared to when a rotational driving force is input to. That is, when the reciprocating driving force is transmitted to the blades 3a and 3b via the second power transmission path, the blade is compared with when the reciprocating driving force is transmitted to the blades 3a and 3b via the first power transmission path. Although the driving speeds of 3a and 3b are reduced, the driving force is increased. In other words, the cutting speed becomes slow, but the cutting force increases. Therefore, in the following description, a state where the reciprocating driving force is transmitted to the blades 3a, 3b via the first power transmission path (a state where the electric motor 10 is rotating forward) is referred to as a “high speed low torque mode”. A state in which the reciprocating driving force is transmitted to the blades 3a and 3b via the second power transmission path (a state in which the electric motor 10 is reversed) may be referred to as a “low speed high torque mode”.

  The number of reduction stages of the first reduction mechanism provided in the first power transmission path and the number of reduction stages of the second reduction mechanism provided in the second power transmission path are both one (odd number). Therefore, the direction of the rotational driving force input to the conversion mechanism is reversed between the high speed low torque mode and the low speed high torque mode. That is, the rotation direction of the driven shaft 24 and the cam 40 fixed thereto is reversed (reversed) when the electric motor 10 is rotated forward and backward, and the reciprocating direction of the blades 3a and 3b is also reversed. (Reversed). However, if the number of speed reduction stages of the first speed reduction mechanism and the second speed reduction mechanism is unified to either an odd number or an even number, the above operation can be obtained regardless of the number of speeds.

  Next, an example of control executed by the control circuit provided on the circuit board 13 shown in FIG. 2 will be described with reference mainly to FIGS. In steps S1 to S2 shown in FIG. 5, the electric motor 10 is activated with the first switch 11 and the second switch 12 shown in FIG. 2 being pressed. The rotation direction of the electric motor 10 at this time is a normal rotation direction.

  Next, in step S3 shown in FIG. 5, it is determined whether or not the blades 3a and 3b shown in FIG. 1 are locked. That is, it is determined whether or not the rotation of the electric motor 10 shown in FIG. 2 is stopped. If the blades 3a and 3b are locked, the process proceeds to step S4 shown in FIG. 5, and the rotation direction of the electric motor 10 shown in FIG. 2 is reversed. That is, the electric motor 10 starts to rotate in the reverse rotation direction opposite to the normal rotation direction.

  When the electric motor 10 shown in FIG. 2 starts reverse rotation, the process proceeds to step S5 shown in FIG. 5 to determine again whether or not the blades 3a and 3b shown in FIG. 1 are locked. If the blades 3a and 3b are locked, the process proceeds to step S6 shown in FIG. 5, and the electric motor 10 shown in FIG. 2 is stopped.

  As described above, when the blades 3a and 3b shown in FIG. 1 bite into a thick branch or a hard branch and stop (lock) while working in the high speed and low torque mode, the mode is automatically switched to the low speed and high torque mode. That is, the rotation direction of the electric motor 10 shown in FIG. 2 is automatically reversed. Accordingly, the blades 3a and 3b that have bitten into the branches and leaves reciprocate in the opposite direction, so that the bites into the branches and leaves are easily released. Furthermore, when the blades 3a and 3b that have been released from the branches and leaves again come into contact with the branches and leaves, the cutting force of the blades 3a and 3b is increased. Therefore, there are cases where even branches and leaves that could not be cut earlier can be cut.

  However, regardless of whether the blades 3a and 3b shown in FIG. 1 are locked, the rotation direction of the electric motor 10 can be reversed manually. That is, when thick branches or hard branches and leaves appear during work in the high speed / low torque mode, the blades 3a, 3b can be locked by switching to the low speed / high torque mode by manual operation. Therefore, it is possible to omit the pre-work of cutting and removing thick branches and hard branches and leaves in advance.

  Further, when it is determined in step S5 shown in FIG. 5 that the blades 3a and 3b (FIG. 1) are locked, control to return to step S2 is also possible.

  As described above, according to the hedge trimmer 1 according to the present embodiment, an improvement in the efficiency of various operations using the hedge trimmer 1 can be expected.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, although the conversion mechanism is constituted by a cam and a connecting member, an embodiment in which the conversion mechanism is constituted only by the cam is also included in the present invention. An embodiment in which three or more clutches are provided on the power transmission path is also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Hedge trimmer 2 Housing 3 Blade assembly 3a, 3b Blade 4 Rear handle 5 Front handle 6 Battery 10 Electric motor 11 First switch 12 Second switch 13 Circuit board 14 Trigger 15 Push pin 16 Switching panel 20 Drive shaft 21, 25 One-way clutch 21a , 25a Inner ring 21b, 25b Outer ring 22, 23 Bearing 24 Drive shaft 31 First gear 32 Second gear 33 Third gear 34 Fourth gear 40 Cam 40a First engaging portion 40b Second engaging portion 41 First connecting member 42 Second connecting member

Claims (3)

A reciprocating machine with a reciprocating working tool,
A motor capable of forward and reverse rotation,
A conversion mechanism for reciprocating the working tool by converting the rotational driving force output from the motor into a reciprocating driving force;
A first power transmission path that is provided between the motor and the conversion mechanism, and that inputs a rotational driving force output from the motor during normal rotation of the motor to the conversion mechanism;
A second power transmission path that is provided between the motor and the conversion mechanism and that inputs a rotational driving force output from the motor to the conversion mechanism when the motor is reversely rotated;
A first speed reduction mechanism disposed in the first power transmission path;
A second reduction mechanism disposed in the second power transmission path and having a reduction ratio different from that of the first reduction mechanism;
The rotational direction of the rotational driving force input to the conversion mechanism via the first power transmission path is opposite to the rotational direction of the rotational driving force input to the conversion mechanism via the second power transmission path. A reciprocating machine.   2. The reciprocating operation machine according to claim 1, wherein the number of speed reduction stages of the first speed reduction mechanism and the second speed reduction mechanism is one of an odd number or an even number. A first clutch that is disposed in the first power transmission path and that switches between a fastening state in which a rotational driving force output from the motor is input to the conversion mechanism and a released state in which the rotational driving force is not input;
A second clutch that is disposed in the second power transmission path and that switches between a fastening state in which a rotational driving force output from the motor is input to the conversion mechanism and a released state in which the rotational driving force is not input;
At the time of forward rotation of the motor, the first clutch is switched to the engaged state, and the second clutch is switched to the released state,
The reciprocating operation machine according to claim 1 or 2, wherein when the motor is reversely rotated, the first clutch is switched to a released state and the second clutch is switched to an engaged state.

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