JP5353116B2 - Reciprocating cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce vibration generated on a tool body at cutting work with a reciprocating cutting tool. <P>SOLUTION: The reciprocating cutting tool includes a balancer 10 reciprocating with a phase shifted by 180 degrees (an antiphase) with respect to a plunger 7 in cooperation with reciprocal motion of the plunger 7. The balancer 10 moves in a direction separating from the plunger 7 at a top dead center and a bottom dead center of vertical reciprocating motion, and moves in a direction approaching the plunger 7 at an intermediate position between the top dead center and the bottom dead center. Thus the vibration of the tool body can be reduced. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a reciprocating cutting tool provided with a balancer for suppressing vibration caused by reciprocating movement of a cutter.

  A conventional reciprocating cutting tool will be described with reference to FIGS.

  As shown in FIG. 21, a jigsaw that is a reciprocating cutting tool has a motor 2 that is an electric motor built in a housing 1, a handle 3 is provided above the housing 1, and the handle 3 has a switch 4. doing. The housing 1 incorporates a reciprocating conversion mechanism 5 for converting the rotational force of the motor 2 into a reciprocating motion in the vertical direction shown in the figure. A plunger 7 for holding a cutter 6 is attached to the reciprocating conversion mechanism 5. It has been. The reciprocating conversion mechanism unit 5 includes a speed reducing unit 5 a for decelerating the rotation of the motor 2, and a converting unit 5 b for converting the rotation transmitted from the speed reducing unit 5 a into the reciprocating motion of the plunger 7. 1 is supported. Further, a base 9 serving as a guide member at the time of cutting work is attached below the housing 1.

  In order to drive a jigsaw having such a configuration, when an operator grasps the handle 3 and turns on the switch 4, the motor 2 rotates, and this rotation causes the speed reduction unit 5a and the conversion unit 5b constituting the reciprocating conversion mechanism unit 5. Is converted into a reciprocating motion in the vertical direction of the housing 1, the plunger 7 holding the blade 6 is reciprocated by the motion converting portion 5 b, and the blade 6 reciprocates together with the plunger 7. A base 9 that comes into contact with the workpiece is attached to the housing 1 or the holder 4, and the base 9 slides on the workpiece while the blade 6 is reciprocated, so that the cutting work can be performed. ing.

  Here, a balancer 10 is attached to the reciprocating conversion mechanism 5 so as to be positioned near the plunger 7 and shifted in the front-rear direction of the drawing. Two pin portions 8 a are fixed to the holder 8, and this pin portion 8 a is inserted into a long hole portion 10 a provided in the balancer 10. When the motor 2 rotates, the balancer 10 reciprocates with a phase (opposite phase) shifted by 180 degrees from the plunger 7 to relieve the vertical inertia force generated by the reciprocating motion of the plunger 7 and to vibrate the reciprocating cutting tool body. It is comprised so that may be reduced.

JP 2006-175524 A

  In the above-described reciprocating cutting tool (jigsaw), the vertical reciprocating motion of the plunger 7 that holds the blade 6 and the balancer 10 that relieves the inertial force of the plunger 7 is not on the same axis, that is, as shown in FIGS. As described above, the balancer 10 is disposed so as to be displaced in the front-rear direction (the left-right direction in the drawing) with respect to the plunger 7. Accordingly, as shown in FIG. 22, when the plunger 7 is moved to the top dead center and the balancer 10 is moved to the bottom dead center, the inertial force indicated by the arrow A is generated on the plunger 7 and the inertial force indicated by the arrow B is generated on the balancer 10. As shown in FIG. On the other hand, as shown in FIG. 23, when the plunger 7 moves to the bottom dead center and the balancer 10 moves to the top dead center, the plunger 7 generates the inertial force indicated by the arrow A ′ and the balancer 10 generates the inertial force indicated by the arrow B ′. As a result, a rotational force indicated by an arrow C ′ is generated.

  Accordingly, it has been found that since the rotational force is generated when the plunger 7 and the balancer 10 are moved to the top dead center and the bottom dead center, this rotational force causes vibration in the reciprocating cutting tool body.

  An object of the present invention is to provide a reciprocating cutting tool that relieves the inertial force (rotational force) described above and reduces vibration of the reciprocating cutting tool body.

  The object is to provide a housing containing an electric motor, a motion conversion unit that is built in the housing and converts the rotational motion of the electric motor into a reciprocating motion, and is reciprocally held in the housing so as to protrude outside the housing. A plunger that reciprocates in the vertical direction of the housing using the rotational force of the electric motor as a power source, and that holds a blade that cuts the cutting material, and is displaced in the front-rear direction with respect to the plunger and has an opposite phase. In a reciprocating cutting tool having a balancer that reciprocates in a vertical direction between a top dead center and a bottom dead center, a moving direction conversion unit that converts the movement of the balancer in a direction different from the vertical reciprocating direction, The balancer can be achieved by moving away from the plunger as it moves in the direction of the dead center.

  With such a configuration, the balancer operates in the opposite phase according to the vertical movement of the plunger and operates so as to approach and separate from the plunger, so that the rotational force generated by the plunger and the balancer can be reduced. The vibration of the tool body can be suppressed.

  The balancer may be closest to the plunger when positioned at an intermediate position between the top dead center and the bottom dead center.

  With this configuration, the balancer moves away from the plunger at the top dead center and bottom dead center, so the rotational force generated by the plunger and the balancer can be reduced, and the vibration of the tool body is suppressed. can do.

  The direction changing portion includes a protrusion provided on one of the housing and the balancer, and a groove provided on the other side into which the protrusion is inserted, and the protrusion is inserted into the groove. Then, the movement of the balancer may be guided. The protrusion is provided in the housing, the groove is provided in the balancer, and has an arc shape extending in the vertical direction, and the arc-shaped end portion is provided closest to the plunger. It may be done.

  With such a configuration, the rotational force generated by the plunger and the balancer can be reduced with a simple configuration, and the vibration of the tool body can be suppressed.

  The protrusion is provided on the balancer, the groove is provided in the housing and has an arc shape extending in the vertical direction, and the end of the arc shape is provided farthest from the plunger. It may be done.

  With this configuration, the balancer can move up and down and back and forth along the arc-shaped groove, so the rotational force generated by the plunger and the balancer can be reduced with a simple configuration, and the vibration of the tool body is suppressed. can do.

  In addition, the groove is provided at two positions spaced apart in the vertical direction of the housing, and the arc shape of the groove located on the upper side of the groove has an upper end portion farthest from the plunger and the plunger An intermediate portion that is closest to the upper end portion, and a lower end portion that is located between the upper end portion and the intermediate portion, and the arc shape of the groove portion that is located on the lower side of the groove portion is a lower end that is most spaced from the plunger. And an intermediate portion closest to the plunger, and an upper end portion located between the lower end portion and the intermediate portion.

  With this configuration, the balancer operates like a pendulum when the balancer is moved up and down and back and forth with respect to the vertical movement of the plunger, so that the rotational force generated by the plunger and the balancer can be further reduced. And vibration of the tool body can be suppressed.

  According to the present invention, since the balancer is configured to approach and separate from the plunger, the rotational force of the tool body caused by the displacement of the arrangement position of the plunger and the balancer can be reduced, and a reciprocating cutting tool with less vibration can be obtained. Can be provided.

  An embodiment of a reciprocating cutting tool according to the present invention will be described with reference to FIGS. In the drawings, parts having functions similar to those of the prior art are denoted by the same reference numerals.

  First, the configuration of a reciprocating cutting tool, such as a jigsaw, according to the present invention will be described with reference to FIGS. As shown in FIGS. 1 to 3, a motor 2 that is an electric motor is built in a housing 1, a handle 3 is provided above the housing 1, and the handle 3 has a switch 4. The housing 1 incorporates a reciprocating conversion mechanism 5 for converting the rotational force of the motor 2 into a reciprocating motion in the vertical direction shown in the figure. A plunger 7 for holding a cutter 6 is attached to the reciprocating conversion mechanism 5. It has been. The reciprocating conversion mechanism unit 5 includes a speed reducing unit 5a for decelerating the rotation of the motor 2, and a converting unit 5b for converting the rotary motion transmitted from the speed reducing unit 5a into the reciprocating motion of the plunger 7, and the speed reducing unit 5a. The converter 5 b is connected by a bolt 12 and supported by the housing 1 by a holder 8. The conversion unit 5b supports the balancer 10 and the plunger 7 so as to reciprocate in opposite phases. Further, a base 9 serving as a guide member at the time of cutting work is attached below the housing 1.

  Next, a method for driving the jigsaw of this configuration will be described. When the operator grips the handle 3 and turns on the switch 4, the rotation of the motor 2 is transmitted to the reciprocating conversion mechanism unit 5 through a gear provided on the motor shaft. A reduction gear 5a that forms the rear part 5 of the reciprocating converter is formed with a gear that meshes with the gear of the motor shaft. The rotation of the motor 2 is transmitted to the reciprocating conversion mechanism 5, and the rotation of the motor 2 is decelerated and rotated. The speed reduction part 5a which comprises the reciprocating conversion mechanism part 5 centering on the axis | shaft 11 rotates. When the speed reduction part 5a rotates, power is transmitted to the conversion part 5b connected by the bolt 12, but since the conversion part 5b is provided eccentrically with respect to the rotating shaft 11, the plunger connected to the conversion part 5b. 7, the rotational motion of the motor 2 is converted into a reciprocating motion and transmitted. That is, the rotational motion of the motor 2 is converted into a reciprocating motion in the vertical direction of the housing 1 by the reciprocating conversion mechanism 5 and transmitted to the plunger 7 and transmitted to the blade 6 supported by the plunger 7. 7 and the blade 6 also reciprocate. Therefore, by cutting the base 9 attached to the housing 1 or the holder 8 on the material to be cut, the cutting work of the material to be cut by the blade 6 can be performed.

  The state of FIG. 1 shows a case where the plunger 7, that is, the blade 6 is located at the top dead center. When the conversion unit 5 b makes a quarter turn from this state, the plunger 7 moves downward by a predetermined distance from the top dead center. It moves and it will be in the state of FIG. If the motor 2 is further rotated from this state and the conversion unit 5b is further rotated by a quarter of a turn (half rotation from the state of FIG. 1), the plunger 7 moves to the bottom dead center and becomes the state of FIG. By repeating the state shown in FIGS. 1 to 3, the plunger 7 (the blade 6) can reciprocate to cut the workpiece.

  Here, the balancer 10 is attached to the reciprocating conversion mechanism unit 5 (converting unit 5b) so as to be positioned in the vicinity of the plunger 7 and shifted in the front-rear direction of the drawing. Two pin portions 8 a are fixed to the holder 8, and this pin portion 8 a is inserted into a long hole portion 10 a provided in the balancer 10 to guide the balancer 10. When the motor 2 rotates, the balancer 10 reciprocates with a phase (opposite phase) shifted from the plunger 7 by 180 °, relieves the vertical inertia force generated by the reciprocating motion of the plunger 7, and vibrates the reciprocating cutting tool body. It is comprised so that may be reduced. In the state of FIG. 1, the balancer 10 is located at a bottom dead center that is opposite to the plunger 7 in the vertical direction. In the state of FIG. 2, it is located at a position moved upward by a predetermined distance from the bottom dead center, and in the state of FIG. 3, it is located at a top dead center that is opposite to the plunger 7 in the vertical direction. That is, the balancer 10 moves up and down (reciprocates) with a phase (opposite phase) shifted by 180 ° with respect to the plunger 7. As a result, vibration caused by the reciprocating motion of the plunger 7 can be reduced. In the present invention, in order to further reduce this vibration, the balancer 10 is moved not only in the vertical direction but also in the front-rear direction, which will be described in detail below with reference to FIGS.

  First, the reciprocating motion of the balancer 10 with respect to the reciprocating motion of the plunger 7 will be described with reference to FIG. FIG. 4 shows the position of the balancer 10 when the plunger 7 is located at the top dead center, the bottom dead center, or the middle point between the top dead center and the bottom dead center. When the plunger 7 is located at the top dead center (7C), the balancer 10 is located at the bottom dead center (10C). When the plunger 7 moves to the bottom dead center (7A), the balancer 10 moves to the top dead center (10A). When the plunger 7 moves to the intermediate position (7B) between the top dead center and the bottom dead center, the balancer 10 similarly moves to the intermediate position (10B).

  However, the conventional balancer 10 merely reciprocates in the opposite phase to the plunger 7 in conjunction with the reciprocation of the plunger 7. In the present invention, as shown in FIG. 4, there is a gap L between the transmission portion 5a and the conversion portion 5b of the plunger 7 so that the balancer 10 can operate in the front-rear direction while being supported by the conversion portion 5b of the balancer 10. (FIG. 8) is provided, and the balancer 10 is also provided so as to be movable in the direction approaching / separating from the plunger 7 (front-rear direction), so that the vibration of the tool body caused by the reciprocating motion of the plunger 7 is further reduced. It is configured to be able to.

  That is, the balancer 10 reciprocates in the vertical direction in the opposite phase to the reciprocating movement of the plunger 7, but in addition to the operation, as shown by the arrow H in FIG. The plunger 7 can be moved closer to or away from the plunger L by a distance L, and can be reciprocated so as to draw an arc with an opposite phase to the reciprocating movement of the plunger 7 in the vertical direction.

  Next, the operation of the balancer 10 with respect to the reciprocating motion of the plunger 7 will be described in detail with reference to FIGS.

  First, a mechanism for moving the balancer 10 in the vertical direction and the front-rear direction will be described. Two arc-shaped grooves 13 are provided on the surface of the balancer 10 along the longitudinal direction thereof. A projection 14 provided inside the housing 1 or the holder 8 is fitted in the groove 13. The protrusion 14 is fixed to the housing 1 regardless of the reciprocation of the plunger 7, and the balancer 10 moves along the groove 13 with respect to the protrusion 14, so that the protrusion 14 can move in the vertical direction and the front-rear direction. .

  The state shown in FIG. 5 is the initial position of the plunger 7 and the balancer 10. In this state, the plunger 7 is at the top dead center, and the balancer 10 is at the bottom dead center because the phase is opposite to that of the plunger 7 and is spaced apart from the plunger 7. Here, the distance between the plunger 7 and the balancer 10 is L1. From this state, when the plunger 7 moves downward, the balancer 10 also moves in a phase opposite to that of the plunger 7, and the state shown in FIG. 6 is obtained. In this state, the plunger 7 is positioned between the top dead center and the bottom dead center described later, and the balancer 10 is similarly positioned between the top dead center and the bottom dead center. The balancer 10 also moves in the direction approaching the plunger 7, and the distance L2 from the plunger 7 is smaller than L1 (L2 <L1). Further, the plunger 7 moves downward to reach the state shown in FIG. In this state, the plunger 7 is at the bottom dead center, the balancer 10 is at the top dead center, and is spaced apart from the plunger 7, and the distance L3 to the plunger 7 is the same as the distance L1 shown in FIG. 5 (L3 = L1). ). The positional relationship between the plunger 7 and the balancer 10 is the same when returning from the state of FIG. 7 to the state of FIG. That is, when the plunger 7 is located at the top dead center, the balancer 10 is located at the bottom dead center and at the farthest position with respect to the plunger 7. The balancer 10 moves upward as the plunger 7 moves downward. Furthermore, it moves in a direction approaching the plunger 7. When the plunger 7 is positioned between the top dead center and the bottom dead center, the balancer 10 is also positioned at the intermediate position and is closest to the plunger 7. When the plunger 7 further moves downward, the balancer 10 moves upward and moves away from the plunger 7. When the plunger 7 moves to the bottom dead center, the balancer 10 moves to the top dead center and is located farthest from the plunger 7. Accordingly, the balancer 10 reciprocates in the opposite phase in conjunction with the reciprocating movement of the plunger 7, and moves with respect to the plunger 7 so as to draw an arc (an arc motion opposite to the arc shape of the groove 14) by the groove 14 and the protrusion 13. Move away and approach.

  By the above reciprocating motion, a force due to the reciprocating motion as shown in FIGS. 8 and 9 is generated, and the rotational force of the tool body can be reduced. FIG. 8 shows a state in which the plunger 7 is moved away from the plunger 7 at the top dead center and the balancer 10 is moved away from the plunger 7. In this case, an inertial force A is generated in the plunger 7 in the direction of arrow A upward. An inertial force B is generated in the balancer 10 in the direction of arrow B downward. Since the plunger 7 and the balancer 10 are displaced in the front-rear direction, the rotational force C is generated by the inertial forces A and B. However, in the present invention, the balancer 10 moves away from the plunger 7 as it moves downward from the intermediate position (distance L in the drawing), so that an inertial force D indicated by an arrow D is generated. Therefore, since the inertial force D is generated in the direction opposite to the rotational force C, the inertial force D acts in the direction of reducing the rotational force C. As a result, the rotational force of the tool body can be reduced and vibration can be reduced. That is, it is possible to provide a reciprocating cutting tool in which the inertia force generated by the reciprocation of the reciprocating axis of the vertical reciprocating motion of the plunger 7 and the balancer 10 is alleviated and vibration is reduced.

  On the other hand, FIG. 9 shows a state where the plunger 7 is moved from the bottom dead center and the balancer 10 is moved away from the plunger 7 at the top dead center. In this case, an inertial force A ′ is generated in the plunger 7 in the direction of the arrow A ′. In the balancer 10, an inertial force B 'is generated in the direction of the arrow B' upward. Inertial forces A 'and B' generate a rotational force C 'in the direction opposite to that in FIG. However, in the present invention, the balancer 10 moves in the direction away from the plunger 7 as it moves upward from the intermediate position, so that an inertial force D 'indicated by an arrow D' is generated. Accordingly, since the inertial force D ′ is generated in the direction opposite to the rotational force C ′, the inertial force D ′ acts in the direction of reducing the rotational force C ′, and the rotational force of the tool body can be reduced as in FIG. be able to. Note that the distance that the balancer 10 moves in the front-rear direction when moving from the intermediate position to each dead point is L. If this distance L is increased, the vibration of the tool body can be further reduced.

  In the above-described embodiment, the groove 13 is provided on the surface of the balancer 10 and the protrusion is provided on the inside of the housing 1 or the holder 8. However, the protrusion is provided on the surface of the balancer 10, and the groove is provided on the inside of the housing 1 or the holder 8. The same effect can be obtained by providing. Hereinafter, a second embodiment according to the present invention will be described with reference to FIGS. 10 to 20. 2nd Embodiment changes the moving direction of the balancer 10 with respect to 1st Embodiment.

  FIGS. 10 and 11 show a state in which the plunger 7 (the blade 6) is located at the top dead center and the bottom dead center, respectively, and corresponds to FIGS. 1 and 3 of the first embodiment. The moving direction of is different.

  As shown in FIG. 12, the balancer 10 is configured to reciprocate up and down in the opposite phase with respect to the reciprocating motion of the plunger 11 in the up-and-down direction, and is also movable in the front-and-rear direction. When the plunger 7 is located at the top dead center (7C), the balancer 10 is located at the bottom dead center (10C). When the plunger 7 moves to the intermediate point (7B), the balancer 10 moves to the intermediate position (10B). When the plunger 7 further moves to the bottom dead center (7A), the balancer 10 moves to the top dead center (10A). 7 and the balancer 10 repeat reciprocating motions in the vertical direction due to an antiphase relationship.

  While the plunger 7 reciprocates in the vertical direction in the direction of the arrow X, the balancer 10 moves in the arc as shown by the arrow Y because it moves in the front-rear direction in addition to the vertical movement. That is, as the balancer 10 moves to the top dead center (10A) side, the upper part of the balancer 10 moves away from the plunger 7 and the lower part of the balancer 10 moves in a direction approaching the plunger 7. Conversely, as the balancer 10 moves to the bottom dead center (10C) side, the upper part of the balancer 10 moves in a direction approaching the plunger 7 and the lower part of the balancer 10 moves in a direction away from the plunger 7. When the balancer 10 is positioned at the intermediate position (10B), the upper and lower portions of the balancer 10 are at the same distance from the plunger 7 and are positioned in parallel with the plunger 7. The operation of the balancer 10 with respect to the reciprocating movement of the plunger 7 will be described in detail with reference to FIGS.

  The basic configuration of the jigsaw shown in FIG. 13 is the same as that of the first embodiment, but arcuate grooves 13 are provided in two locations spaced apart in the vertical direction inside the housing 1 or the holder 8. Two protrusions 14 (one on each side surface) that are inserted into the groove 13 are provided integrally with the balancer 10 on the surface (side surface) of the balancer 10. The balancer 10 can reciprocate as the projection 14 slides along the groove 13 formed in the housing 1 or the holder 8 according to the reciprocation of the plunger 7. The groove 13 is formed in an arc shape so that the intermediate portion is closest to the plunger 7 and both ends are farthest from the plunger 7. Further, of the two grooves 13, the upper groove 13 a is formed such that the arc-shaped upper end portion 13 a 1 is separated from the plunger 7 than the lower end portion 13 a 2. On the other hand, the lower groove 13b is formed such that the arc-shaped upper end 13b1 is separated from the plunger 7 rather than the lower end 13b2, and the upper end 13a1 of the groove 13a is closer to the groove 13b. The upper end portion 13b1 is formed away from the plunger 7, and the lower end portion 13a2 of the groove 13a is formed closer to the plunger 7 than the lower end portion 13b2 of the groove 13b. Therefore, when the balancer 10 moves to the top dead center, the upper end side of the balancer 10 is separated from the plunger 7 from the lower end side, and when the balancer 10 moves to the bottom dead center, the lower end side of the balancer 10 is separated from the plunger 7 from the upper end side. Therefore, the rotational force of the tool body can be reduced and vibration can be reduced. The groove lengths of the grooves 13a and 13b are the same.

  The operation of the balancer 10 will be described with reference to FIGS. The state shown in FIG. 14 is an initial position of the plunger 7 and the balancer 10. In this state, the plunger 7 is at the top dead center, and the balancer 10 is at the bottom dead center because the phase is opposite to that of the plunger 7, and the upper end of the balancer 10 approaches the plunger 7, and the lower end of the balancer 10 Is spaced from the plunger 7. From this state, when the plunger 7 moves downward, the balancer 10 also moves in a phase opposite to that of the plunger 7, and the state shown in FIG. 15 is obtained. In this state, the plunger 7 is positioned between the top dead center and the bottom dead center, and the balancer 10 is similarly positioned between the top dead center and the bottom dead center. The upper end of the balancer 10 moves in a direction away from the plunger 7, the lower end of the balancer 10 moves in a direction approaching the plunger 7, and the distances from the plunger 7 at the upper end and the lower end are substantially equal. Without. When the plunger 7 further moves downward to the state of FIG. 16, the plunger 7 is located at the bottom dead center, the balancer 10 is located at the top dead center, and the upper end of the balancer 10 is located away from the plunger 7. The lower end of the balancer 10 is located close to the plunger 7. The positional relationship between the plunger 7 and the balancer 10 is the same when returning from the state of FIG. 16 to the state of FIG. That is, when the plunger 7 is located at the top dead center, the balancer 10 is located at the bottom dead center, and the lower end of the balancer 10 is located farthest from the plunger 7 so that the plunger 7 moves downward. Accordingly, the balancer 10 moves upward, and the upper end of the balancer 10 moves away from the plunger 7 and the lower end moves toward the plunger 7. When the plunger 7 is positioned between the top dead center and the bottom dead center, the balancer 10 is also in the intermediate position, and the distance between the upper end portion and the lower end portion of the balancer 10 from the plunger 7 becomes equal. When the plunger 7 further moves downward, the balancer 10 moves upward and the upper end of the balancer 10 moves away from the plunger 7. When the plunger 7 moves to the bottom dead center, the balancer 10 moves to the top dead center, and the upper end portion of the balancer 10 is positioned farthest from the plunger 7. Accordingly, the balancer 10 reciprocates in the opposite phase in conjunction with the reciprocating movement of the plunger 7 and moves in a direction away from and approaching the plunger 7 so as to draw an arc by the groove 13 and the protrusion 14. Furthermore, since the upper end portions (13a1 and 13b1) and the lower end portions (13a2 and 13b2) of the two grooves 13 (13a and 13b) are formed at positions shifted in the front-rear direction, the vertical movement of the balancer 10 and In addition to the longitudinal movement, the balancer 10 moves like a pendulum, so that the vibration of the main body 1 can be further reduced.

  Next, FIG. 17 shows the relationship between the plunger 7 and the balancer 10 when FIG. 14 is viewed from the front side (right side), and FIG. 18 shows the position of the balancer 10. FIGS. 17A to 17C and FIGS. 18A to 18C correspond to FIGS. 14 to 16, respectively. 18 is a cross-sectional view taken along the line AA in FIG. The plunger 7 is provided with a guide portion 7a provided on the conversion portion 5b and connected to the plunger 7 to guide the connector 5c. Further, the balancer 10 is provided with a guide hole 10 b for transmitting the eccentric motion of the converting portion 5 b with respect to the rotating shaft 11 to the balancer 10. Here, using FIGS. 17 and 18, the plunger 7 moves from the top dead center and the balancer 10 to the bottom dead center, and the plunger 7 moves to the bottom dead center and the balancer 10 to the top dead center. The operation will be described.

  The rotation of the motor 2 is decelerated by the decelerating unit 5a, and the converting unit 5b converts the rotational movement into a reciprocating movement. First, the rotation of the motor 2 is transmitted to the rotating shaft 11. The conversion unit 5b is provided at a position eccentric with respect to the rotation shaft 11, and when the rotation shaft 11 rotates, the conversion unit 5b and the connector 5c attached to the conversion unit 5b also rotate. At this time, the connector 5c moves in the up / down direction while moving in the left / right direction in FIG. 17 along the guide portion 7a of the plunger 7 along with the rotation of the conversion unit 5b. That is, the rotational motion of the motor 2 can be converted into the reciprocating motion of the plunger 7 by the converting portion 5b and the connector 5c. At this time, the balancer 10 moves in the vertical direction in the opposite phase to the plunger 7 by the projection 14 sliding in the groove 13 along with the eccentric rotation of the converting portion 5b in the guide hole 10b. It is configured.

  By the reciprocating motion described above, a force due to the reciprocating motion as shown in FIGS. 19 and 20 is generated, and the rotational force of the tool body can be reduced. FIG. 19 shows a state in which the plunger 7 is at the top dead center, the balancer 10 is at the bottom dead center, and the lower end of the balancer 10 is moved away from the plunger 7. In this case, an inertial force A is generated in the plunger 7 in the direction of the arrow A upward. An inertial force B is generated in the balancer 10 in the direction of arrow B downward. Since the plunger 7 and the balancer 10 are displaced in the front-rear direction, the rotational force C is generated by the inertial forces A and B. However, in the present embodiment, the lower end portion of the balancer 10 moves away from the plunger 7 as it moves downward from the intermediate position, and the upper end portion moves in a direction approaching the plunger 7, so that the inertia force D indicated by the arrow D is reached. Will occur. Therefore, since the inertial force D is generated in the direction opposite to the rotational force C, the inertial force D acts in the direction of reducing the rotational force C. As a result, the rotational force of the tool body can be reduced and vibration can be reduced. That is, it is possible to provide a reciprocating cutting tool in which the inertial force generated by the reciprocal movement of the reciprocating shaft of the plunger 7 and the balancer 10 in the up-and-down reciprocating motion is reduced and the vibration of the main body is reduced.

  On the other hand, FIG. 20 shows a state in which the plunger 7 is at the bottom dead center, the balancer 10 is at the top dead center, and the upper end of the balancer 10 is moved away from the plunger 7. In this case, an inertial force A ′ is generated in the plunger 7 in the direction of the arrow A ′. In the balancer 10, an inertial force B 'is generated in the direction of the arrow B' upward. Inertial forces A 'and B' generate a rotational force C 'in the direction opposite to that in FIG. However, in this embodiment, as the balancer 10 moves upward from the intermediate position, the upper end moves away from the plunger 7 and the lower end moves in the direction approaching the plunger 7. 'Will occur. Accordingly, since the inertial force D ′ is generated in the direction opposite to the rotational force C ′, the inertial force D ′ acts in the direction of reducing the rotational force C ′, and the rotational force of the tool body can be reduced as in FIG. be able to. In addition, if the movement amount of the upper end part and the lower end part of the balancer 10 is increased, the vibration of the tool body can be further reduced.

  In this embodiment, a groove is provided on one of the balancer and the housing, and a protrusion is provided on the other. However, when the balancer 10 moves upward and downward, the balancer 10 comes into contact with the balancer 10 and moves away from the plunger 7. A member for restricting movement may be provided, and the rotational force generated by the plunger and the balancer may be reduced.

It is a partial cross section figure in case the plunger of the reciprocating cutting tool used as the 1st Embodiment of this invention exists in a top dead center. It is a partial cross section figure in case the plunger of the reciprocating cutting tool used as the 1st Embodiment of this invention exists in an intermediate position. It is a partial cross section figure in case the plunger of the reciprocating cutting tool used as the 1st Embodiment of this invention exists in a bottom dead center. It is a principal part enlarged view which shows the state which the balancer of the reciprocating cutting tool used as the 1st Embodiment of this invention moves between a top dead center and a bottom dead center. It is principal part partial sectional drawing which shows the balancer side surface in case the plunger of the reciprocating cutting tool used as the 1st Embodiment of this invention exists in a top dead center. It is principal part partial sectional drawing which shows the balancer side surface in case the plunger of the reciprocating cutting tool used as the 1st Embodiment of this invention exists in an intermediate part. It is principal part partial sectional drawing which shows the balancer side surface in case the plunger of the reciprocating cutting tool which becomes the 1st Embodiment of this invention exists in a bottom dead center. It is principal part sectional drawing which shows the inertia force when the plunger of the reciprocating cutting tool used as the 1st Embodiment of this invention moves to a top dead center. It is principal part sectional drawing which shows the inertial force when the plunger of the reciprocating cutting tool used as the 1st Embodiment of this invention moves to a bottom dead center. It is a partial cross section figure in case the plunger of the reciprocating cutting tool used as the 2nd Embodiment of this invention exists in a top dead center. It is a partial cross section figure in case the plunger of the reciprocating cutting tool used as the 2nd Embodiment of this invention exists in a bottom dead center. It is a principal part enlarged view which shows the state which the balancer of the reciprocating cutting tool used as the 2nd Embodiment of this invention moves between a top dead center and a bottom dead center. It is a partial cross section figure in case the plunger of the reciprocating cutting tool used as the 2nd Embodiment of this invention exists in a top dead center. It is a principal part fragmentary sectional view which shows the balancer side surface of the reciprocating cutting tool used as the 2nd Embodiment of this invention, and is a figure which shows the case where a plunger exists in a top dead center. It is a principal part fragmentary sectional view which shows the balancer side surface of the reciprocating cutting tool used as the 2nd Embodiment of this invention, and is a figure where a plunger shows an intermediate position. It is a principal part fragmentary sectional view which shows the balancer side surface of the reciprocating cutting tool used as the 2nd Embodiment of this invention, and is a figure which shows the case where a plunger exists in a bottom dead center. It is a figure which shows the positional relationship of the plunger and balancer which looked at FIG. 14 from the plunger side. It is AA sectional drawing of FIG. It is principal part sectional drawing which shows the inertial force at the time of the plunger of the reciprocating cutting tool used as the 2nd Embodiment of this invention moving to a top dead center. It is principal part sectional drawing which shows the inertial force when the plunger of the reciprocating cutting tool used as the 2nd Embodiment of this invention moves to a bottom dead center. It is a partial cross section figure in case the plunger of the conventional reciprocating cutting tool exists in a top dead center. It is a partial cross section figure in case the plunger of the conventional reciprocating cutting tool exists in a bottom dead center. It is principal part sectional drawing which shows the inertia force when the plunger of the conventional reciprocating cutting tool moves to a top dead center. It is principal part sectional drawing which shows the inertial force at the time of the plunger of the conventional reciprocating cutting tool moving to a bottom dead center.

Explanation of symbols

1 is a housing, 2 is an electric motor (motor), 3 is a handle, 4 is a switch, 5 is a reciprocating conversion mechanism, 6 is a cutter, 7 is a plunger, 8 is a holder, 9 is a base, 10 is a balancer, and 11 is a rotating shaft , 12 are bolts, 13 is a groove, and 14 is a protrusion.

Claims (5)

A housing containing an electric motor;
A motion converter that is built in the housing and converts the rotary motion of the electric motor into a reciprocating motion;
A plunger that is reciprocally held in the housing so as to protrude to the outside of the housing, reciprocates in the vertical direction of the housing using the rotational force of the electric motor as a power source, and holds a cutter that cuts a cutting material;
In a reciprocating cutting tool having a balancer that is displaced in the front-rear direction with respect to the plunger and reciprocates in the vertical direction between the top dead center and the bottom dead center in an opposite phase,
A movement direction conversion unit that converts the movement of the balancer in a direction different from the vertical reciprocating direction, and the balancer moves away from the plunger as it moves in the dead center direction, and the top dead center and the bottom dead center A reciprocating cutting tool that is closest to the plunger when positioned at an intermediate position of a point. The direction changing portion includes a protrusion provided on one of the housing and the balancer, and a groove provided on the other and into which the protrusion is inserted.
The reciprocating cutting tool according to claim 1, wherein the protrusion is inserted into the groove to guide the movement of the balancer. A housing containing an electric motor;
A motion converter that is built in the housing and converts the rotary motion of the electric motor into a reciprocating motion;
A plunger that is reciprocally held in the housing so as to protrude to the outside of the housing, reciprocates in the vertical direction of the housing using the rotational force of the electric motor as a power source, and holds a cutter that cuts a cutting material;
In a reciprocating cutting tool having a balancer that is displaced in the front-rear direction with respect to the plunger and reciprocates in the vertical direction between the top dead center and the bottom dead center in an opposite phase,
A movement direction conversion unit for converting the movement of the balancer into a direction different from the up and down reciprocating direction;
The direction changing portion includes a protrusion provided on the housing, and a groove provided on the balancer into which the protrusion is inserted.
Guide the movement of the balancer by inserting the protrusion into the groove ,
The groove has an arc shape extending in the vertical direction, and the end of the arc shape is provided closest to the plunger, and the balancer moves away from the plunger as it moves in the dead center direction. A reciprocating cutting tool characterized by that. A housing containing an electric motor;
A motion converter that is built in the housing and converts the rotary motion of the electric motor into a reciprocating motion;
A plunger that is reciprocally held in the housing so as to protrude to the outside of the housing, reciprocates in the vertical direction of the housing using the rotational force of the electric motor as a power source, and holds a cutter that cuts a cutting material;
In a reciprocating cutting tool having a balancer that is displaced in the front-rear direction with respect to the plunger and reciprocates in the vertical direction between the top dead center and the bottom dead center in an opposite phase,
A movement direction conversion unit for converting the movement of the balancer into a direction different from the up and down reciprocating direction;
The direction changing portion includes a protrusion provided on the balancer, and a groove provided in the housing and into which the protrusion is inserted.
Guide the movement of the balancer by inserting the protrusion into the groove,
The groove has an arc shape extending in the vertical direction, and the end of the arc shape is provided farthest from the plunger, and the balancer moves away from the plunger as it moves in the dead center direction. A reciprocating cutting tool characterized by that. The groove portion is provided in two locations apart in the vertical direction of the housing,
The circular arc shape of the groove portion located on the upper side of the groove portion includes an upper end portion farthest from the plunger, an intermediate portion closest to the plunger, and a lower end located between the upper end portion and the intermediate portion. Part
The circular arc shape of the groove portion located on the lower side of the groove portion includes a lower end portion farthest from the plunger, an intermediate portion closest to the plunger, and an upper end located between the lower end portion and the intermediate portion. The reciprocating cutting tool according to claim 4, further comprising a portion.

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