JP2013144341A - Reciprocating tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify an internal structure of a reciprocating mechanism, since there is a problem of complicating the internal structure for incorporating various parts such as a mechanism for decelerating a rotation output of an electric motor, a motion converting mechanism for reciprocating an output rod, a counterweight for restraining vibration and an orbital motion mechanism, for example, in a reciprocating saw.SOLUTION: A decelerating mechanism such as a gear train is omitted by using an outer rotor motor capable of outputting low speed rotation and high torque as an electric motor 10, and an output rod 7 is reciprocated by a cam mechanism 21 including a cylindrical groove cam 22 arranged in an outer rotor 12 so that an internal structure is simplified by reducing the number of part items.

Description

  The present invention relates to a reciprocating cutting tool called a reciprocating saw, for example, which relates to a reciprocating tool that converts a rotational output of a drive motor into a linear motion and outputs the linear motion. In addition to the reciprocating saw, the reciprocating tool includes a jigsaw, a hedge trimmer, a hammer, a hammer drill, and the like.

The reciprocating saw has a configuration in which the rotational output of the drive motor incorporated in the main body is converted into a reciprocating motion in the axial direction of the output rod on which the blade is mounted via a motion conversion mechanism such as a crank mechanism, and is output. Techniques relating to reciprocating saws are disclosed in the following patent documents. Patent Document 1 includes a configuration in which the rotational output of a horizontal electric motor arranged in parallel with the output rod is transmitted to a crank plate after being decelerated through a bevel gear. Patent Document 2 has a configuration in which the rotational output of a vertical electric motor orthogonal to the output rod is transmitted to a crank plate after being decelerated via a spur gear. In either case, the reciprocating direction component due to the revolving movement of the eccentric roller attached to the crank plate is transmitted as the reciprocating movement of the output rod.
As disclosed in these patent documents, in general reciprocating saws, the rotational output of the drive motor is decelerated through the meshing of the gears and then output as a reciprocating motion of the output rod through the motion conversion mechanism. Yes.

JP-A-2005-14111 JP 2009-241242 A

As described above, in a conventional general reciprocating saw, in addition to a speed reduction mechanism such as gear meshing, it is necessary to incorporate a motion conversion mechanism such as a crank plate provided with an eccentric roller.
In addition, the reciprocating saw is provided with a model in which an orbital mechanism for giving a slight orbital motion to the output rod is provided in order to increase the cutting efficiency of the blade. Furthermore, some models are provided with a counterweight that reciprocates in the opposite direction to the output rod in order to reduce vibration associated with the reciprocation of the output rod. In the conventional reciprocating saw having these various functions, there is a problem that the number of parts increases and the structure becomes complicated.
The present invention has been made in view of such conventional problems, and an object thereof is to simplify the structure by reducing the number of parts of a reciprocating tool such as a reciprocating saw.

The above problems are solved by the following invention.
The first invention includes an electric motor as a drive source and a motion conversion mechanism that converts the rotational output of the electric motor into a reciprocating motion of the output rod. The electric motor is provided on the outer peripheral side of the stator (stator). An outer rotor motor having a rotating outer rotor (rotor) is used, and a reciprocating tool in which a motion conversion mechanism is interposed between the outer rotor and an output rod.
According to the first aspect of the present invention, the outer rotor motor capable of rotating at a low speed and outputting a high torque is provided as a drive source, and the rotational power of the outer rotor of the outer rotor motor is directly reciprocated by the output rod via the motion conversion mechanism. Since it is output, the rotation output of the outer rotor motor is converted into the reciprocating motion of the output rod and output without passing through a speed reduction mechanism by conventional gear meshing or the like. From this, the number of parts can be reduced by the amount of the speed reduction mechanism by the conventional gear meshing or the like, and the structure of the reciprocating tool can be simplified.
2nd invention is a reciprocating tool provided with the cam mechanism as a motion conversion mechanism in 1st invention.
According to the second invention, for example, a cylindrical groove cam is provided on the outer peripheral side of the rotating outer rotor, and a cam follower portion that engages with the cam groove of the cylindrical groove cam is provided on the output rod, so that the cam curve of the cam groove is appropriately set. Thus, the rotation of the outer rotor can be converted into the reciprocating motion of the output rod through this cam mechanism.
According to a third invention, in the first or second invention, the motion conversion mechanism includes a cam mechanism having a cam groove and a follower that is unevenly fitted in the cam groove, and one of the cam groove and the follower is provided on the outer peripheral surface of the outer rotor. A reciprocating tool provided on the output rod is provided on the other side.
According to the third invention, one of the cam groove or the follower constituting the cam mechanism is directly provided on the outer peripheral surface of the outer rotor of the electric motor, whereby the configuration can be simplified and the number of parts can be reduced. The increase can be suppressed.
A fourth invention is a reciprocating tool according to any one of the first to third inventions, wherein the forward speed and the backward speed of the output rod are different.
According to the fourth invention, the working efficiency of the reciprocating tool can be increased.
A fifth invention is a reciprocating tool including a counterweight that reciprocates in a direction opposite to the output rod in any one of the first to fourth inventions.
According to the fifth aspect, vibration due to the reciprocating motion of the output rod can be suppressed.
A sixth invention is a reciprocating tool according to any one of the first to fifth inventions, wherein the counterweight is coaxially supported by the output rod.
According to the sixth aspect of the present invention, the counterweight can be supported so as to be able to reciprocate using the output rod, and the increase in the number of parts is suppressed, thereby maintaining the simple configuration and accompanying the reciprocating motion of the output rod. Vibration can be suppressed.
In a seventh aspect of the present invention, in any one of the first to sixth aspects, the reciprocation point at which the moving speed of the counterweight is zero is set as the reciprocation point at which the movement speed of the output rod is zero. It is a reciprocating tool with a fixed time delay.
According to the seventh aspect of the invention, the actual vibration associated with the reciprocating motion of the output rod can be more effectively suppressed in accordance with the overall characteristics of the reciprocating tool.
An eighth invention is a reciprocating tool according to any one of the first to seventh inventions, wherein the outer rotor is provided with a cam portion for giving an orbital motion to the output rod.
According to the eighth invention, a slight orbital motion (elliptical motion) can be given to the output rod by utilizing the rotation of the outer rotor, and at this point, an increase in the number of parts of the reciprocating tool is suppressed. Orbital motion can be imparted to the output rod without complication.

It is a longitudinal cross-sectional view of the reciprocating tool which concerns on this embodiment. This figure has shown the state at the time of an output rod moving to a forward end. It is a longitudinal cross-sectional view of the reciprocating tool which concerns on this embodiment. This figure has shown the state at the time of an output rod moving to a retreat end. It is a perspective view of the cylindrical groove cam simple substance which comprises the cam mechanism as a motion conversion mechanism. It is an expanded view of a cylindrical groove cam.

Next, an embodiment of the present invention will be described with reference to FIGS. As illustrated, in this embodiment, as an example of the reciprocating tool 1, a reciprocating cutting tool called a so-called reciprocating saw is illustrated. The reciprocating tool 1 includes a tool main body 2 that includes an electric motor 10 as a drive source, and a D-shaped handle 3 that is provided at the rear of the tool main body 2. A rechargeable battery pack 4 is attached to the lower portion of the handle portion 3. The battery pack 4 is a lithium ion battery and can be used repeatedly by being removed and charged. When the switch lever 5 provided inside the handle portion 3 is pulled with a fingertip, the electric motor 10 is activated using the battery pack 4 as a power source. A shoe 6 to be brought into contact with the cutting material is provided at the front portion of the tool main body 2 so as to protrude forward.
The tool body 2 includes an electric motor 10, a motion conversion mechanism 20, and an output rod 7. A so-called outer rotor motor is used for the electric motor 10. This outer rotor motor is a motor that can rotate at a low speed and output a high torque as compared with an inner rotor motor. A cylindrical outer rotor (rotor) 12 is provided on the outer peripheral side of a non-rotating stator (stator) 11. The structure supported rotatably is provided, and the rotation of the outer rotor 12 becomes the rotation output of the electric motor 10.
The stator 11 is fixed to the main body housing 2 a side via a support shaft 13 so as not to rotate. The outer rotor 12 is rotatably supported on the outer peripheral side of the stator 11 via the support shaft 13. Therefore, the outer rotor 12 is supported so as to be rotatable around the axis J13 of the support shaft 13.

In the present embodiment, a cam mechanism 21 is used as the motion conversion mechanism 20. The cam mechanism 21 includes a cylindrical groove cam 22 and a cam follower portion 7a. As shown in the figure, in the case of the present embodiment, a cam groove 23 is provided on the outer peripheral surface of the outer rotor 12 of the electric motor 10 to constitute a cylindrical groove cam 22. Therefore, in the present embodiment, the outer rotor 12 of the electric motor 10 and the cylindrical groove cam 22 of the cam mechanism 21 are configured as a single member. FIG. 3 shows the cylindrical groove cam 22 alone. The cylindrical groove cam 22 (outer rotor 12) has a cylindrical shape and is provided with two cam grooves 23 and 24 on the outer peripheral surface thereof. Both cam grooves 23 and 24 are shown expanded in FIG.
The front cam groove 23 is used for reciprocating the output rod 7. The output rod reciprocating cam groove 23 has a displacement in the direction of the axis J13 corresponding to the reciprocating distance of the output rod 7 for one rotation of the outer rotor 12. The rear cam groove 24 is used for reciprocating the counterweight 8. The counterweight reciprocating cam groove 24 has a displacement in the direction of the axis J13 corresponding to the reciprocating distance of the counterweight 8 with respect to one rotation of the outer rotor 12. The rear counterweight reciprocating cam groove 24 has a displacement direction in the axis J13 direction opposite to that of the front output rod reciprocating cam groove 23.
A cam follower portion 7 a provided integrally with the output rod 7 is inserted into the cam groove 23 for reciprocating output rod on the front side. A cam follower portion 8a of the counterweight 8 supported by the output rod 7 is inserted into the cam groove 24 for reciprocating the counterweight on the rear side. The counterweight 8 is supported on the rear side of the output rod 7 so as to be reciprocally movable in the axial direction in a relative and coaxial manner.

The output rod 7 is supported so as to be able to reciprocate in the direction of the axis J7 via bearings 15 and 16 with respect to the main body housing 2a. The output rod 7 is supported by the front bearing 15 so as to be tiltable up and down within a certain angle range. The rear bearing 16 is supported so that it can be displaced in a certain range up and down. The rear bearing 16 is biased downward by a compression spring 17. An orbital roller 18 is attached to the outer periphery of the rear bearing 16. The orbital roller 18 is placed on a lift cam portion 25 provided at the rear end portion of the outer rotor 12 (cylindrical groove cam 22). This mounted state (contact state) is held by the compression spring 17. The orbital roller 18 is displaced up and down by the displacement of the lift cam portion 25 due to the rotation of the cylindrical groove cam 22, so that the rear side bearing 16 is displaced up and down, whereby the rear side of the output rod 7 is displaced up and down. A so-called orbital motion (elliptical motion) is applied to the rod 7 by adding a vertical movement on the rear side to a reciprocating motion in the direction of the axis J7.
A one-touch detachable clamping device 9 is attached to the front end of the output rod 7. With this clamping device 9, the blade B can be attached to the front end of the output rod 7.

When the user pulls the switch lever 5 with the fingertip of the hand holding the handle portion 3, the electric motor 10 is activated. When the electric motor 10 is started, the cylindrical groove cam 22 provided integrally along the periphery of the outer rotor 12 rotates integrally around the axis J13. The cam follower portion 7 a of the output rod 7 is engaged with the front cam groove 23 of the cylindrical groove cam 22, and the cam follower portion 8 a of the counterweight 8 is engaged with the rear cam groove 24. Therefore, when the cylindrical groove cam 22 of the cam mechanism 21 rotates, the output rod 7 reciprocates in the direction of the axis J7, and the counterweight 8 reciprocates in the direction opposite to the output rod 7.
A lift cam portion 25 is provided at the rear end portion of the cylindrical groove cam 22. For this reason, when the electric motor 10 is activated and the cylindrical groove cam 22 rotates, the output rod 7 and the counterweight 8 reciprocate in opposite directions as described above, and a bearing that supports the rear side of the output rod 7. 16 is displaced up and down to give orbital motion to the output rod 7. As shown in FIG. 2, when the output rod 7 reaches the retracted end, the rear side is displaced most upward, and when the output rod 7 reaches the advanced end, the rear side is displaced most downward. For this reason, the output lot 7 and the blade 8 reciprocate along the elliptical locus in the clockwise direction in FIGS.
Further, in the cam mechanism 21 in the present embodiment, as shown in FIG. 4, the forward end position 24a of the rear counterweight reciprocating cam groove 24 is the backward end position 23b of the front output rod reciprocating cam groove 23. In contrast, the rotational direction of the outer rotor 12 (the direction indicated by the white arrow in FIG. 4) is shifted backward by an angle θ. Further, the backward end position 24b of the rear cam groove 24 is deviated by an angle θ rearward in the rotational direction with respect to the forward end position 23a of the front cam groove 23. Therefore, after the output rod 7 reaches the forward end, the counterweight 8 reaches the backward end with a slight time difference, and after the output rod 7 reaches the backward end, the counterweight 8 has a slight time difference. Reaches the forward end.

According to the reciprocating tool 1 of the present embodiment configured as described above, an outer rotor motor capable of rotating at a low speed and outputting a high torque is incorporated as the electric motor 10 as a drive source. The 12 rotational powers are directly output as the reciprocating motion of the output rod 7 via the motion conversion mechanism 20. For this reason, the rotational output of the electric motor 10 is converted into the reciprocating motion of the output rod 7 and output without passing through a speed reduction mechanism by conventional gear meshing or the like. From this, the number of parts can be reduced by the amount of the speed reduction mechanism by the conventional gear meshing or the like, and the structure of the reciprocating tool 1 can be simplified.
In addition, since speed reduction means such as meshing of gears can be omitted, the reciprocating tool 1 can be made compact in the machine length direction (in the direction of the axis J7 of the output rod 7), and its noise reduction and durability can be improved. In addition, power transmission efficiency can be improved.
Further, since the outer rotor motor is used as the electric motor 10, the flywheel effect (the output rod 7 of the output rod 7) is caused by applying a large inertial force of the outer rotor 12 to a reciprocating motion in which the axial force of the output rod 7 changes greatly. Smooth reciprocating motion).

Further, in the reciprocating tool 1 of the present embodiment, the cam groove 23 for reciprocating the output rod and the cam groove 24 for reciprocating the counterweight are directly provided on the outer peripheral side of the outer rotor 12, and the cylindrical groove cam 22 is formed on the outer rotor 12. Since it is provided integrally, the structure of the reciprocating tool 1 can be simplified also in this respect.
Furthermore, since the output rod 7 is configured to reciprocate by the cam mechanism 21 in which the cam follower portion 7a is engaged with the cam groove 23 of the cylindrical groove cam 22, the cam curve of the cam groove 23 is set appropriately. The moving speed at the time of forward movement (at the time of forward movement) and the movement speed at the time of backward movement (at the time of backward movement) can be different. For example, in the path from the forward end position 23a to the backward end position 23b of the cam groove 23 (the upper half circumference range in FIG. 4 and the backward movement range of the output rod 7), the output rod 7 and Increasing the retreating speed of the blade B and making the cam groove slant more gently in the path from the retreat end position 23b to the advance end position 23a (the lower half circumference range in FIG. 4 and the forward movement range of the output rod 7). Thus, the forward speed of the output rod 7 and the blade B can be further reduced.
Thus, the working efficiency of the reciprocating tool 1 can be further increased by changing the moving speed of the output rod 7 between the forward movement and the backward movement.

As the counterweight 8 reciprocates in the opposite direction in accordance with the reciprocating motion of the output rod 7, the vibration of the output rod 7 is absorbed and reduced. Since the counterweight 8 is configured to reciprocate on the output rod 7, the structure of the reciprocating tool 1 can be simplified by suppressing an increase in the number of parts in this respect as well.
Regarding the moving speed of the counterweight 8 and the timing of the reciprocating motion, the characteristics and work of the reciprocating tool 1 can be determined by appropriately setting the cam groove 24 on the rear side of the cylindrical groove cam 22 with respect to the cam groove 23 on the front side. It can be set arbitrarily according to the content.
In the present embodiment, the forward end position 24a and the backward end position 24b, which are reciprocal turning points where the moving speed of the counterweight 8 becomes zero, are reciprocating points where the moving speed of the output rod 7 becomes zero. The rotation angle of the cylindrical groove cam 22 is set to be delayed by an angle θ with respect to the backward end position 23b and the forward end position 23a. Thereby, generation | occurrence | production of the vibration accompanying the reciprocation of the output rod 7 can be absorbed and suppressed more efficiently according to the characteristic of the reciprocation tool 1 concerned.
The cylindrical groove cam 22 is provided with a lift cam portion 25 in addition to the cam grooves 23 and 24. An orbital motion can be applied to the output rod 7 by the lift cam portion 25, and the cutting ability or work efficiency of the reciprocating tool 1 can be enhanced.
As described above, the cylindrical groove cam 22 is integrally provided on the outer rotor 12 of the electric motor 10, and the cylindrical groove cam 22 has a cam groove 23 for reciprocating the output rod 7 and a counterweight 8. A cam groove 24 for reciprocating movement and a lift cam portion 25 for orbital movement of the output rod 7 along an elliptical locus are integrally provided, and at these points, the number of parts of the reciprocating movement tool 1 is suppressed. Therefore, the internal structure can be simplified.

Various modifications can be made to the embodiment described above. For example, in the cam mechanism 21, the cam groove 23, 24 is provided in the cylindrical groove cam 22, and the cam follower portions 7a, 8a are respectively inserted into the cam groove 21, but the cam convex portion is replaced with the cam groove 23, 24 in the same path. The cam projections may be sandwiched between a pair of roller followers provided on the output rod and counterweight sides, respectively, so that the concavity and convexity are reversed.
Moreover, although the cam mechanism 21 was illustrated as the motion conversion mechanism 20, it is good also as a structure which replaces with this and uses a crank mechanism. In this case, for example, the electric motor can be arranged vertically, the crank plate can be provided integrally with the outer rotor, and the eccentric roller provided on the crank plate can be engaged with the output rod to reciprocate. Such a configuration can also simplify the configuration by omitting a speed reduction mechanism such as a gear train.
Further, the illustrated embodiment is not limited to the DC power supply type, and can be similarly applied to an AC power supply type reciprocating tool.
Furthermore, although the battery-type reciprocating saw is illustrated as the reciprocating tool 1, the present invention can be similarly applied to an AC power source-type reciprocating saw. In addition to reciprocating saws (reciprocating cutting tools), other reciprocating tools such as jigsaws, hedge trimmers, hammers, hammer drills, etc. that convert the rotational output of an electric motor into a reciprocating motion of a rod via a motion conversion mechanism and output it. The same applies to.

1 ... Reciprocating tool (Reciprocating saw)
DESCRIPTION OF SYMBOLS 2 ... Tool body part, 2a ... Main body housing 3 ... Handle part 4 ... Battery pack 5 ... Switch lever 6 ... Shoe 7 ... Output rod, 7a ... Cam follower part 8 ... Counterweight, 8a ... Cam follower part 9 ... Clamp device 10 ... Electricity Motor (outer rotor motor)
DESCRIPTION OF SYMBOLS 11 ... Stator 12 ... Outer rotor 13 ... Support shaft J13 ... Axis line of support shaft 13 (Rotation axis line of outer rotor 12)
DESCRIPTION OF SYMBOLS 15 ... Bearing 16 ... Bearing 17 ... Compression spring 18 ... Orbital roller 20 ... Motion conversion mechanism 21 ... Cam mechanism 22 ... Cylindrical groove cam 23 ... Cam groove (for output rod reciprocation)
23a ... Advance end position, 23b ... Backward end position 24 ... Cam groove (for counterweight reciprocation)
24a ... advance end position, 24b ... reverse end position 25 ... lift cam part B ... blade

Claims (8)

It is equipped with an electric motor as a drive source and a motion conversion mechanism that converts the rotational output of the electric motor into the reciprocating motion of the output rod,
As the electric motor, an outer rotor motor provided with an outer rotor rotating on the outer peripheral side of the stator is used, and the reciprocating tool in which the motion conversion mechanism is interposed between the outer rotor and the output rod. The reciprocating tool according to claim 1, wherein the reciprocating tool includes a cam mechanism as the motion conversion mechanism. 3. The reciprocating tool according to claim 1, further comprising: a cam mechanism having a cam groove and a follower that is unevenly fitted in the cam groove as the motion conversion mechanism, wherein one of the cam groove and the follower is the outer rotor. A reciprocating tool provided on the outer peripheral surface and the other provided on the output rod. The reciprocating tool according to any one of claims 1 to 3, wherein a forward moving speed and a backward moving speed of the output rod are different. The reciprocating tool according to any one of claims 1 to 4, further comprising a counterweight that reciprocates in a direction opposite to the output rod. The reciprocating tool according to any one of claims 1 to 5, wherein the counterweight is coaxially supported by the output rod. The reciprocating tool according to any one of claims 1 to 6, wherein a reciprocating point at which the moving speed of the counterweight is zero is a reciprocating point at which the moving speed of the output rod is zero. A reciprocating tool with a fixed time delay from the turning point. The reciprocating tool according to any one of claims 1 to 7, wherein the outer rotor includes a cam portion for giving an orbital motion to the output rod.

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