JP2010023189A - Reciprocating working tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration reduction technology by a counter weight smoothly operated without accompanying linear reciprocation in a reciprocating working tool. <P>SOLUTION: The reciprocating working tool has the first and second bevel gears 123, 147 opposedly arranged across a pinion 119 and rotated and driven by the pinion 119 in an opposite direction at the same speed-reduction ratio; and a slider 107 linearly reciprocated and driven in a long axis direction of a distal end tool by a crank 129. On the first and second bevel gears 123, 147, first and second counter weights 143, 145 are provided at positions deviated from a rotation axis, and when the first counter weight 143 and the second counter weight 145 are subjected to revolution motion, a component in the long axis direction of the distal end tool opposedly acts relative to linear motion of the slider 107, becomes the same phase each other regarding the long axis direction of the distal end tool, and is opposed at an equal distance to each other across the long axis regarding a direction crossing the long axis direction of the distal end tool. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration isolating technique for a reciprocating work tool such as a reciprocating saw or a jigsaw in which a tip tool reciprocates to cut a workpiece.

  Japanese Patent Laying-Open No. 2005-14111 (Patent Document 1) describes the configuration of a reciprocating saw. This reciprocating saw according to the prior art includes a counterweight that performs a linear reciprocating motion opposite to the slider when the cutting tool is reciprocated through a crank by means of a motor to reciprocate the slider to which the tip tool is attached. ing. That is, the counterweight is moved linearly in the direction opposite to the slide, thereby reducing the vibration generated when the slider reciprocates.

According to the reciprocating saw vibration reduction method in which the counterweight is reciprocated in the opposite phase to the linear reciprocating motion of the slider, the momentum mainly composed of inertial force can be canceled between the slider and the counterweight in the long axis direction of the slider. Reasonable vibration reduction is possible. However, there is still room for improvement in that vibration due to collision occurs when the counterweight changes the direction of movement, and energy loss occurs due to the change of direction of movement.
JP-A-2005-14111

  The present invention has been made in view of this point, and an object of the present invention is to provide a vibration reduction technique using a counterweight that operates smoothly without a linear reciprocating motion in a reciprocating work tool.

  In order to achieve the above object, a preferred embodiment of a reciprocating work tool according to the present invention is a reciprocating work tool that performs a predetermined machining operation on a workpiece by reciprocating a tip tool in a long axis direction. An output shaft of a motor arranged in parallel to the long axis direction of the tip tool, a pinion provided on the output shaft, meshingly engaged with the pinion, and driven to rotate about an axis intersecting the long axis direction of the tip tool A first bevel gear, a crank that is fixed to the first bevel gear, and that converts the rotational motion of the first bevel gear to linear motion, and that holds the tip tool and is linear in the longitudinal direction of the tip tool via the crank's linear motion And a slider that is driven back and forth. The “reciprocating work tool” in the present invention includes work tools used for various work materials such as woodwork, metalwork, masonry, etc., and reciprocating saws or jigsaws used for cutting work materials. Etc. are widely included. The “crank” in the present invention typically includes a rotating shaft to which the first bevel gear is fixed, an eccentric pin disposed at a position deviated by a predetermined distance from the rotating axis of the rotating shaft, a rotating shaft and an eccentric pin. Are configured to have crank plates that join each other.

  According to a preferred embodiment of the reciprocating work tool according to the present invention, as a characteristic configuration, the first bevel gear is disposed coaxially with the rotation axis of the first bevel gear so as to be opposed to the first bevel gear and engaged with the pinion. A second bevel gear that is rotationally driven in a direction opposite to the bevel gear, a first counterweight that is disposed at a position eccentric from the rotation axis of the first bevel gear by a predetermined distance, and that rotates integrally with the first bevel gear; The second bevel gear further includes a second counterweight that is disposed at a position eccentric from the rotation axis of the two bevel gear by a predetermined distance and that rotates together with the second bevel gear. The first counterweight and the second counterweight are set so that the component in the long axis direction of the tip tool opposes the linear motion of the slider when revolving around the rotation axis of the first bevel gear. Further, a first counterweight configured to be in phase with each other with respect to the major axis direction of the tip tool, and to face each other at an equal distance across the major axis with respect to a direction intersecting with the major axis direction of the tip tool; This is the second counter weight.

  In the present invention, the “first counter weight rotating integrally with the first bevel gear” is an aspect in which the first counter weight is provided in the first bevel gear, or an aspect in which the first counter weight is provided in the crank rotating integrally with the first bevel gear. Any of these are preferably included. In addition, the “first counterweight” in the present invention suitably includes either an aspect in which a separate member is attached to the first bevel gear or the crank, or an aspect in which the first counterweight is integrally formed with the first bevel gear or the crank. . Similarly, the “second counterweight” in the present invention suitably includes both an aspect in which a separate member is attached to the second bevel gear, or an aspect in which the second counterweight is integrally formed with the second bevel gear.

  According to the present invention, when the first counterweight and the second counterweight perform the revolving motion (circular motion) around the rotation axis of the crank, the tip tool long axis direction component (when the long axis direction of the tip tool is horizontal) The momentum of the forward and backward direction component) opposes the linear momentum of the slider, thereby reducing the vibration caused by the linear reciprocating motion of the slider. On the other hand, the momentum of the first counterweight and the second counterweight rotating in the opposite directions cancel each other in the direction intersecting the tip tool major axis direction (left and right direction when the tool tool major axis direction is horizontal). And unnecessary vibrations do not occur.

  As described above, according to the present invention, it is possible to reduce vibrations by smooth operation using the rotational motion of the first and second counterweights. Unlike conventional methods that reduce vibration by counter reciprocating movement of the counterweight, problems such as generation of vibration due to collision when the counterweight changes the direction of movement, or generation of energy loss due to change of movement direction, etc. Is resolved.

  According to the further form of the reciprocating work tool according to the present invention, the teeth of the first bevel gear and the teeth of the second bevel gear have the same number of teeth. By adopting such a configuration, when the first and second counterweights perform the revolving motion (circular motion) around the rotation axis of the crank via the first bevel gear and the second bevel gear, the first and second It is possible to rationally construct a counter weight mechanism having a simple configuration with no deviation in operation timing between the two counter weights.

  According to the further form of the reciprocating work tool according to the present invention, the first bevel gear and the second bevel gear are formed by different molding methods. The first bevel gear used for driving the slider receives a larger load than the second bevel gear used for driving the second counterweight. For this reason, the first bevel gear is manufactured using a material having high strength, for example, formed by cutting, while the second bevel gear having a smaller load than the first bevel gear is inexpensive and easily manufactured. For example, it is preferable to form by a sintering method, and the durability of both bevel gears can be set to be approximately the same.

  According to the further form of the reciprocating work tool according to the present invention, the crank is a rotation shaft that rotates integrally with the first bevel gear, and an eccentricity that is arranged at a position that is eccentric from the rotation axis of the rotation shaft by a predetermined distance. A pin and a crank plate that is provided at one end in the longitudinal direction of the rotating shaft and joins the rotating shaft and the eccentric pin to each other. A first counterweight is attached to the crank plate, and a second bevel gear is disposed on the crank plate side of the rotating shaft, and the second bevel gear has a first counterweight facing the first counterweight. Two counter weights are arranged. According to such a configuration, the first counterweight and the second counterweight can be disposed close to each other in the direction of the rotation axis of the crank. As a result, even imbalance in the direction intersecting with the long axis direction of the crank is reduced, which is effective in suppressing unnecessary vibration.

  According to the further form of the reciprocating work tool according to the present invention, the first counterweight is fitted to the eccentric pin and fixed to the crank plate at a position away from the fitting portion. By adopting such a configuration, the eccentric pin can be rationally used as a detent member for the counterweight crank plate.

  According to the further form of the reciprocating work tool according to the present invention, the crank is a rotation shaft that rotates integrally with the first bevel gear, and an eccentricity that is arranged at a position that is eccentric from the rotation axis of the rotation shaft by a predetermined distance. A pin and a crank plate that is provided at one end in the longitudinal direction of the rotating shaft and joins the rotating shaft and the eccentric pin to each other. The first bevel gear is fixed to the rotating shaft, and the rotating shaft is rotatably supported by bearings on both sides of the first bevel gear. By setting it as such a structure, about the 1st bevel gear with which load torque acts at the time of a process operation, this can be supported stably and smooth rotation motion can be obtained.

  According to the present invention, in a reciprocating work tool, a vibration reduction technique using a counterweight that operates smoothly without a linear reciprocating motion is provided.

(First embodiment of the present invention)
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. The embodiment of the present invention will be described using a reciprocating saw as an example of a reciprocating work tool. FIG. 1 is a cross-sectional plan view showing the overall configuration of a reciprocating saw 101 according to this embodiment. 2 and 3 are longitudinal sectional views showing the overall configuration of the reciprocating saw 101. FIG. 2 shows a state in which the slider 107 is moved to the forward end (left side in the figure), and FIG. The state moved to (right side) is shown. FIG. 4 is an enlarged cross-sectional view showing the configuration of the main part of the present invention, and FIG. 5 is an explanatory diagram of the operation of the counterweights 143 and 145.

  As shown in FIGS. 1 to 3, the reciprocating saw 101 according to the present embodiment includes a main body portion 103 as a work tool main body constituting the outline of the reciprocating saw 101 when viewed generally, and a slider 107 protruding from the main body portion 103. A blade 111 that is detachably attached to a chuck 109 at the front end and cuts a workpiece (not shown in particular for convenience), and a hand grip 105 that is integrally formed at the rear end of the main body 103 opposite to the blade 111. Is the main constituent. The blade 111 corresponds to the “tip tool” in the present invention.

  The main body 103 includes a motor housing 103 a that houses the drive motor 113 and a gear housing 103 b that houses a motion conversion mechanism 121 that converts the rotational output of the drive motor 113 into a linear motion and transmits the linear motion to the slider 107. For convenience of explanation, the blade 111 side (left side in FIGS. 1 to 3) is referred to as a front side, and the handgrip 105 side (right side in FIGS. 1 to 3) is referred to as a rear side.

  A drive motor 113 is disposed in the motor housing 103a. The drive motor 113 is energized and driven when a trigger 115 disposed on the handgrip 105 is pulled by an operator and the electric switch 115a is turned on. When the drive motor 113 is energized, the blade 111 reciprocates linearly in the long axis direction (front-rear direction) together with the slider 107 and the chuck 109 so that the workpiece can be cut.

  The slider 107 is arranged in an upper region in the internal space of the gear housing 103b when the major axis direction of the blade 111 is set to the horizontal direction, and is arranged in the major axis direction (the major axis direction of the blade 111) via the front and rear bearings 108a and 108b. ) Is reciprocally supported, and is connected to the motor shaft 117 via a motion conversion mechanism 121 in the gear housing 103b. The drive motor 113 is arranged so that the major axis direction of the motor shaft 117 is parallel to the major axis direction of the blade 111, almost directly below the extension of the major axis of the blade 111. The drive motor 113 corresponds to the “motor” in the present invention, and the motor shaft 117 corresponds to the “output shaft” in the present invention.

  The motion converting mechanism 121 is an operating mechanism that converts the rotational motion of the motor shaft 117 into linear reciprocating motion in the major axis direction of the slider 107, and the major axis direction of the blade 111 in the internal space of the gear housing 103b is defined as the horizontal direction. In this case, it is disposed in a lower region, that is, almost directly below the slider 107. The motion conversion mechanism 121 is mainly composed of a drive bevel gear 123, a crank 129, and a slider block 131 that rotate in a horizontal plane. The drive bevel gear 123 corresponds to the “first bevel gear” in the present invention.

  The crank 129 includes a crankshaft 129a extending in the vertical direction intersecting the major axis direction of the blade 111, a crank plate 129b formed integrally with one end (upper end) of the crankshaft 129a in the major axis direction, and the crank plate It is constituted by an eccentric pin 129c provided on the upper surface of 129b at a position eccentric from the center of rotation by a predetermined distance. The crankshaft 129a corresponds to the “rotary shaft” in the present invention. The crankshaft 129a is arranged almost directly below the slider 107, and is configured as a double-supported structure that is rotatably supported by the gear housing 103b via upper and lower bearings 127a and 127b.

  The drive bevel gear 123 is fixed to the upper side (slider 107 side) of the crankshaft 129a, and the teeth formed on the lower side surface are engaged with and engaged with the pinion 119 formed at the tip of the motor shaft 117. The rotation in a horizontal plane with the crankshaft 129a is enabled. The eccentric pin 129c is press-fitted from above into a pin mounting hole formed in the drive bevel gear 123 on the lower end side, and the upper end side is inserted into the guide groove 131a of the slider block 131 formed on the lower surface side of the slider 107 via a bearing 133. It is inserted upward from below. The guide groove 131a of the slider block 131 extends in the horizontal direction intersecting the long axis direction of the slider 107, that is, in the left-right direction, and the eccentric pin 129c is relatively movable along with the bearing 133 along the guide groove 131a. ing.

  Therefore, when the drive motor 113 is energized, the rotation output of the motor shaft 117 is transmitted to the crankshaft 129a via the drive bevel gear 123 that meshes and engages with the pinion 119. When the crankshaft 129a is driven to rotate, the eccentric pin 129c revolves around the rotation axis of the crankshaft 129a (circular movement), and the major axis direction of the slider 107 of the revolving movement intersects with the horizontal plane. The left-right direction motion component is released to the guide groove 131 a and only the motion component in the major axis direction of the slider 107 is transmitted to the slider 107. As a result, the slider 107 is reciprocated linearly only in the front-rear direction. Note that a shoe 106 is provided at the distal end portion of the main body 103 to be pressed toward the workpiece while the operator holds the handgrip 105 during the cutting operation.

  A counterweight mechanism 141 is mounted on the reciprocating saw 101 in order to reduce the vibration in the long axis direction caused by the linear movement of the slider 107. Next, the counterweight mechanism 141 will be described. The counterweight mechanism 141 according to the present embodiment is mainly composed of two counterweights 143 and 145 that perform revolving motion (circular motion) in opposite directions around the rotation axis of the crankshaft 129a in a horizontal plane. One counterweight 143 is attached to the upper side surface portion of the drive bevel gear 123, and the other one counterweight 145 is attached to the lower side surface portion of the reverse rotation bevel gear 147 disposed to face the drive bevel gear 123. The reverse bevel gear 147 corresponds to the “second bevel gear” in the present invention. The driving counterweight 143 attached to the driving bevel gear 123 corresponds to the “first counterweight” in the present invention, and the reverse counterweight 145 attached to the reverse bevel gear 147 is the “second counterweight” in the present invention. Corresponding to In other words, the counter weight mechanism 141 includes two counter weights 143 and 145 and two bevel gears 123 and 147 that drive the counter weights 143 and 145.

  A reverse rotation bevel gear 147 disposed opposite to the drive bevel gear 123 across the pinion 119 (motor shaft 117) is attached to the lower side of the crankshaft 129a via a bearing 149 and formed on the upper side surface portion. The engaged teeth are engaged with and engaged with the pinion 119 of the motor shaft 117. A drive-side counterweight 143 is fixed to the upper side surface portion of the drive bevel gear 123 at a position eccentric from the rotation axis of the drive bevel gear 123 by a predetermined distance, and the rotation of the reverse bevel gear 147 is fixed to the lower side surface portion of the reverse bevel gear 147. A reverse counterweight 145 is fixed at a position eccentric from the axis by a predetermined distance. The drive side and reverse counterweights 143 and 145 are formed in the same weight and shape, and both bevel gears 123 are formed from the center of gravity. , 147, that is, the separation distance to the rotation axis of the crankshaft 129a is set to be the same.

  In the present embodiment, the drive bevel gear 123 and the reversing bevel gear 147 that are arranged opposite to each other are configured to use the pinion 119 as a common component, and therefore, the specifications regarding the teeth are set to be the same. By making the number of teeth of the drive bevel gear 123 and the reverse bevel gear 147 the same, the reduction ratios of both the bevel gears 123 and 147 are determined to be the same. Thus, the drive bevel gear 123 and the reverse bevel gear 147 are configured to be rotated at the same speed in the opposite directions on the same axis. For this reason, there is no deviation in the operation timing between the counterweights 143 and 145 when the driving counterweight 143 and the reverse counterweight 145 revolve. Further, the specifications regarding the drive bevel gear 123 and the reverse bevel gear 147 are also set to be the same for the module and the pitch circle diameter. As a result, the meshing engagement with the pinion 119 becomes the same condition, and the drive bevel gear 123 and the reverse bevel gear 147 It becomes possible to make durability comparable.

  The counterweight mechanism 141 according to the present embodiment is configured as described above. Accordingly, the drive-side counterweight 143 attached to the drive bevel gear 123 and the reverse-side counterweight 145 attached to the reverse rotation bevel gear 147 are energized and driven by the drive motor 113, and the drive bevel gear 123 and the reverse rotation bevel gear 147 via the pinion 119. Are rotated around the rotation axis of the crankshaft 129a in opposite directions (circular motion).

  Regarding the reciprocating motion of the slider 107 and the revolving motion of the counterweights 143 and 145 on the driving side and the reverse side, the position most moved to the front side (tip side) of the reciprocating saw 101 is the bottom dead center, and the rear side (back side) of the reciprocating saw 101. The position most moved to is defined as the top dead center. In the present embodiment, when the slider 107 is moved to the bottom dead center, both the driving counterweight 143 and the reverse counterweight 145 are moved to the top dead center (see FIGS. 2 and 4), and the slider 107 is moved. The drive-side counterweight 143 and the reverse-side counterweight 145 are both set to move to the bottom dead center when moved to the top dead center (see FIG. 3).

  Accordingly, when the slider 107 moves, for example, from the bottom dead center to the top dead center, the drive-side counterweight 143 and the reverse-side counterweight 145 are both from the top dead center to the bottom dead center as shown by arrows in FIG. Revolves around. Of the revolution movements of the counterweights 143 and 145 on the driving side and the reverse side, the momentum in the major axis direction component of the blade 111 acts so as to cancel the momentum of the slider 107. As a result, it is possible to reduce the vibration in the long axis direction, that is, the front-rear direction, which is generated when the slider 107 reciprocates linearly. At this time, the respective momentums of the blade major axis direction components of the counterweights 143 and 145 on the driving side and the reverse side are merged to face the momentum of the slider 107. In FIG. 5, a solid line indicates a state where both the drive-side counter weight 143 and the reverse rotation-side second counter weight 145 are placed at the top dead center.

  Further, the drive-side counterweight 143 and the reverse-side counterweight 145 revolve in opposite directions as shown in FIG. Accordingly, the momentums of the left and right direction components of the drive-side counterweight 143 and the reverse-side second counterweight 145 that make revolving motion are the same in magnitude but in opposite directions. For this reason, in the left-right direction, the momentum of the drive-side counterweight 143 and the reverse rotation-side second counterweight 145 cancel each other, and it is possible to suppress the occurrence of unnecessary vibration.

(Second embodiment of the present invention)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a longitudinal sectional view showing the overall configuration of the reciprocating saw 101 according to the second embodiment, and FIG. 7 is a sectional view showing the configuration of the main part of the reciprocating saw 101. FIG. 8 is a plan view showing the mounting structure of the drive-side counterweight 143, and FIG. 9 is a cross-sectional view taken along line AA in FIG. This embodiment is a modification of the counterweight mechanism 141 provided for reducing vibration, and the configuration other than the counterweight mechanism 141 is the same as that of the first embodiment described above. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  In this embodiment, the drive bevel gear 123 is attached to the lower side of the crankshaft 129a so as to rotate integrally, and the teeth formed on the upper side surface of the drive bevel gear 123 mesh with the pinion 119 of the motor shaft 117. Has been. On the other hand, the reverse bevel gear 147 is attached to the upper side of the crankshaft 129a through a bearing 149 so as to be relatively rotatable, and the teeth formed on the lower side surface thereof are engaged with the pinion 119 of the motor shaft 117. In this way, the drive bevel gear 123 and the reverse bevel gear 147 are disposed to face each other with the pinion 119 (motor shaft 117) interposed therebetween. Accordingly, the reverse rotation bevel gear 147 is rotated in the opposite direction on the same axis as the drive bevel gear 123. The drive bevel gear 123 and the reverse bevel gear 147 have the same specifications regarding the number of teeth and the teeth such as the module as in the embodiment.

The counter weight mechanism 141 includes a drive side counter weight 143 and a reverse side counter weight 145. In the present embodiment, the drive-side counterweight 143 is attached to a crank 129 that rotates integrally with the drive bevel gear 123.
The drive side counterweight 143 mounting structure will be described in more detail. As shown in FIGS. 8 and 9, the drive side counterweight 143 is attached to one end of the upper surface of the flat plate weight support member 151, such as a rivet or screw caulking. It is fixed by 153. The weight support member 151 is overlaid on the upper surface, which is one end surface in the long axis direction of the crank plate 129b, and is fixed to a substantially central portion of the crank plate 129b by a screw 155, and is provided on the opposite side of the drive-side counter weight 143. The pin hole 151a is fitted to the eccentric pin 129c on the crank plate 129b from above. Thus, the drive-side counterweight 143 is disposed at a position that is eccentric from the rotation axis by a predetermined distance with respect to the upper end side in the long axis direction of the crankshaft 129a.

  On the other hand, the reverse counter weight 145 is mounted on the upper surface side of the reverse bevel gear 147 at a position eccentric from the rotation axis of the reverse bevel gear 147 by a predetermined distance. As described above, in the present embodiment, the drive-side counterweight 143 and the reverse-side counterweight 145 are disposed between the pinion 119 (motor output shaft 117) and the slider 107 and sandwich the weight support member 151 therebetween. It is set as the adjacent arrangement | positioning structure which mutually opposes. The counter-counter weight 145 is set so that the momentum in the left-right direction component is offset from the drive-side counter weight 143 by the relationship between the weight including at least the weight support member 151 and the rotation radius.

  The counterweight mechanism 141 according to the present embodiment is configured as described above. Therefore, the drive motor 113 is energized and the slider 107 is driven through the drive bevel gear 123 and the crank 129 so that the top dead center and the bottom dead center are located. When linearly reciprocating between the points, the drive-side counterweight 143 and the reverse-side counterweight 145 revolve around the rotation axis of the crankshaft 129a at the same speed in opposite directions (circular motion). Of the revolution movements of the counterweights 143 and 145 on the driving side and the reverse side, the momentum in the major axis direction of the blade 111 acts so as to cancel the momentum of the slider 107. It is possible to reduce the vibration in the long axis direction, that is, the front-rear direction generated by the reciprocating motion.

  In addition, since the drive-side counterweight 143 and the reverse-side counterweight 145 revolve in opposite directions, the amount of momentum of the left-right direction components of the drive-side counterweight 143 and the reverse-side second counterweight 145 is the same. Opposite direction. For this reason, in the left-right direction, the momentum of the drive-side counterweight 143 and the reverse rotation-side second counterweight 145 cancel each other, and it is possible to suppress the occurrence of unnecessary vibration. As described above, according to the second embodiment, the same operational effects as those of the first embodiment described above can be obtained.

  In particular, in this embodiment, the drive-side counterweight 143 and the reverse-side counterweight 145 are arranged with the weight support member 151 sandwiched between the pinion 119 and the slider 107, and both counterweights 143 and 145 are arranged. It is possible to place them close to each other with a slight distance that can avoid interference with each other in the rotational axis direction. Thereby, even imbalance is reduced. In other words, when the drive-side counterweight 143 and the reverse-side counterweight 145 rotate, they are parallel to each other in opposite directions (radial directions) intersecting the major axis direction of the crankshaft 129a acting on the crankshaft 129a. Force, that is, the moment due to couple force is reduced, which is effective in suppressing the occurrence of unnecessary vibrations.

  In the present embodiment, the crankshaft 129a is configured such that both sides thereof are supported by the bearings 127a and 127b with the drive bevel gear 123 used for transmission of the drive force interposed therebetween. With such a configuration, it is possible to stably support the drive bevel gear 123 on which a load torque acts during a machining operation, and obtain a smooth rotational motion.

  Further, in the present embodiment, the weight support member 151 is fixed to the substantially axial center portion of the crank plate 129b by the screw 155, and the pin hole 151a is fitted to the eccentric pin 129c on the crank plate 129b. That is, with respect to the mounting structure of the weight support member 151, the eccentric pin 129c on the crank plate 129b is used as a detent member. For this reason, even if the screw 155 is loosened, the drive-side counterweight 143 is reliably rotated together with the crank plate 129b.

  Next, a modification regarding the drive timing of the drive side and reverse counter weights 143 and 145 will be described. According to the above-described embodiment, the drive-side and reverse-side counterweights 143 and 145 perform the reciprocating motion of the slider 107 to which the blade 111 is attached and perform the reciprocating motion in the opposite phase, thereby reducing the momentum. Vibration can be reduced. However, in the reciprocating saw 101, in a load driving state in which the workpiece 111 is actually cut using the blade 111 and in a no-load driving state in which the blade 111 is driven in the idling state without being subjected to the cutting operation, Depending on the presence or absence of an external resistance acting on the blade 111, the optimum timing of vibration cancellation by the drive side and reverse counter weights 143 and 145 differs. This is because a cutting resistance acts on the blade 111 in the load driving state, and the phase of the slider 107 that drives the blade 111 by this cutting resistance is easily shifted to the lag side compared to the case of the no-load state. Therefore, it is preferable to set the drive timings of the drive side and reverse rotation counterweights 143 and 145 in consideration of the drive form of the blade 111.

  Accordingly, in view of the above, the phase difference between the reciprocating operation of the slider 107 that drives the blade 111 and the revolving operation of the driving side and reverse counter weights 143 and 145 is such that the arrival timings at the top dead center and the bottom dead center are different. Set to Specifically, the phase of the revolution operation of the drive side and reverse rotation counterweights 143 and 145 is set so as to be relatively delayed from the phase of the reciprocating operation of the slider 107 by 180 degrees. That is, when the reciprocating operation of the slider 107 and the phase of the revolving operation of the driving side and the reverse counter weights 143 and 145 are 180 degrees different from each other, the revolving operation of the driving side and the reverse counter weights 143 and 145 is performed. Is set to be delayed.

This is shown in the schematic diagram of FIG. 10A shows the revolution operation of the eccentric pin 129c in the crank 129 that reciprocates the slider 107, and FIG. 10B shows the revolution operation of the drive side and reverse counter weights 143 and 145. Yes. As shown in the figure, when the eccentric pin 129c is at the bottom dead center P1, the drive side and reverse rotation side counter weights 143 and 145 that revolve in opposite directions are in relation to the top dead center P2 that is in an opposite phase state. Is set to be delayed by a predetermined angle α. And about this delay angle (alpha), the cutting resistance value which appears frequently at the time of the cutting | disconnection operation | work of a workpiece is determined, it is defined as an angle corresponding to the determined cutting resistance value, for example, is set to 15 degrees.
By setting the operation timings of the driving side and reverse rotation side counter weights 143 and 145 as described above, a reasonable vibration reduction measure can be taken in consideration of cutting resistance.

In the present embodiment, the counter weights 143 and 145 on the drive side and the reverse side are formed as separate members, and are attached to the drive bevel gear 123, the reverse bevel gear 147 or the crank 129 as corresponding members. However, it may be formed integrally with the drive bevel gear 123, the reverse bevel gear 147 or the crank 129.
In the present embodiment, the reverse counter weight 145 is directly attached to the reverse bevel gear 147. However, the reverse counter weight 145 is a rotation member that is driven to rotate by the reverse bevel gear 147 or a rotation member that rotates integrally with the reverse bevel gear 147. You may change to the structure which provides the counterweight 145 on the reverse side.
Moreover, although this Embodiment demonstrated using the reciprocating saw 101 as an example of a reciprocating work tool, it applies widely also to the form which a tip tool reciprocates and processes a workpiece, for example, a jigsaw etc. Is possible.

It is a plane sectional view showing the whole reciprocating saw structure concerning this embodiment. It is a longitudinal cross-sectional view which shows the whole structure of a reciprocating saw, and the state to which the slider was moved to the advance end (illustration left side) is shown. It is a longitudinal cross-sectional view which shows the whole structure of a reciprocating saw, and the state by which the slider was moved to the retracted end (illustration right side) is shown. It is sectional drawing which shows the structure of the principal part of a reciprocating saw. It is operation | movement explanatory drawing of a counterweight. It is a longitudinal cross-sectional view which shows the whole structure of the reciprocating saw which concerns on 2nd Embodiment. It is sectional drawing which shows the structure of the principal part of a reciprocating saw. It is a top view which shows the attachment structure of a drive side counterweight. It is the sectional view on the AA line of FIG. It is explanatory drawing regarding the phase of the reciprocating operation | movement of a slider, and the phase of the revolution operation | movement of a drive side and reverse rotation side counterweight.

Explanation of symbols

101 Reciprocating saw (reciprocating work tool)
103 body portion 103a motor housing 103b gear housing 105 hand grip 106 shoe 107 slider 108a front bearing 108b rear bearing 109 chuck 111 blade 113 drive motor 115 trigger 115a electric switch 117 motor shaft (output shaft)
119 Pinion 121 Motion conversion mechanism 123 Drive bevel gear (first bevel gear)
127a Upper bearing 127b Lower bearing 129 Crank 129a Crankshaft (rotating shaft)
129b Crank plate 129c Eccentric pin 131 Slider block 131a Guide groove 133 Bearing 141 Counterweight mechanism 143 Drive-side counterweight (first counterweight)
145 Reverse counter weight (second counter weight)
147 Reversed bevel gear (second bevel gear)
149 Bearing 151 Weight support portion 151a Pin hole 153 Rivet 155 Screw

Claims (6)

A reciprocating work tool that performs a predetermined processing operation on a workpiece by reciprocating a tip tool in a long axis direction,
An output shaft of a motor arranged in parallel with the long axis direction of the tip tool;
A pinion provided on the output shaft;
A first bevel gear meshingly engaged with the pinion and driven to rotate about an axis intersecting the longitudinal direction of the tip tool;
A crank that is fixed to the first bevel gear and converts the rotational motion of the first bevel gear to linear motion;
A slider that holds the tip tool and is driven to reciprocate linearly in the long axis direction of the tip tool through the linear motion of the crank,
A second bevel gear disposed coaxially with the rotation axis of the first bevel gear and opposed to the first bevel gear, meshingly engaged with the pinion, and driven to rotate in a direction opposite to the first bevel gear;
A first counterweight disposed at a position eccentric from the rotation axis of the first bevel gear by a predetermined distance and rotating integrally with the first bevel gear;
A second counterweight disposed at a position eccentric from the rotation axis of the second bevel gear by a predetermined distance and rotating integrally with the second bevel gear;
The first counterweight and the second counterweight are set so that the component in the long axis direction of the tip tool opposes the linear movement of the slider when revolving around the rotation axis of the first bevel gear. In addition, the first tool is configured to be in phase with each other with respect to the major axis direction of the tip tool, and to face each other at an equal distance across the major axis line with respect to the direction intersecting the major axis direction of the tip tool. A reciprocating work tool characterized by comprising a counterweight and a second counterweight. The reciprocating work tool according to claim 1,
The tooth of the first bevel gear and the tooth of the second bevel gear have the same number of teeth. The reciprocating work tool according to claim 1 or 2,
A reciprocating work tool, wherein the first bevel gear and the second bevel gear are formed by different molding methods. The reciprocating work tool according to any one of claims 1 to 3,
The crank is provided at a rotary shaft that rotates integrally with the first bevel gear, an eccentric pin that is disposed at a position that is eccentric from the rotary axis of the rotary shaft by a predetermined distance, and one end portion in the longitudinal direction of the rotary shaft, A crank plate for joining the rotary shaft and the eccentric pin to each other;
The first counter weight is attached to the crank plate, the second bevel gear is disposed on the crank plate side of the rotating shaft, and the second bevel gear is opposed to the first counter weight. The reciprocating work tool is characterized in that the second counterweight is disposed in the reciprocating work tool. The reciprocating work tool according to claim 4,
The reciprocating work tool is characterized in that the first counterweight is fitted to the eccentric pin and is fixed to the crank plate at a position away from the fitting portion. A reciprocating work tool according to any one of claims 1 to 5,
The crank is provided at a rotating shaft that rotates integrally with the first bevel gear, an eccentric pin that is disposed at a position that is eccentric from the rotating axis of the rotating shaft by a predetermined distance, and one end in the longitudinal direction of the rotating shaft, A crank plate for joining the rotary shaft and the eccentric pin to each other;
A reciprocating work tool, wherein the first bevel gear is fixed to the rotating shaft, and the rotating shaft is rotatably supported by bearings on both sides of the first bevel gear.

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