JP2014148030A - Reciprocating tool - Google Patents

Abstract

[PROBLEMS] To suppress an increase in the amplitude of a vibration reduction mechanism even when a voltage temporarily increases due to variations in power supply or the like and a hitting frequency increases, thereby improving durability and downsizing. Provide a reciprocating tool that can be used.
A motion converting mechanism 45 that converts the rotation of an electric motor 11 into a reciprocating motion of a tool 12 and a vibration reducing mechanism 49 that reduces vibrations caused by the operation of the motion converting mechanism 45 are provided. Are provided at both ends of the weights 52 and 53 and the weights 52 and 53, respectively, and are coil springs that urge the weights 52 and 53 to vibrate in the axial direction of the casing 13. The reciprocating tool 10 is in contact with the other weight 53 when the amplitude of one weight 52 exceeds a predetermined amplitude.
[Selection] Figure 1

Description

  The present invention relates to a reciprocating tool such as a hammer drill that reciprocates a tip tool to perform a drilling operation and the like, and particularly relates to a technique for reducing casing vibration caused by the reciprocating motion.

  A reciprocating tool such as a hammer drill or a hammer driver can reciprocate the tip tool to efficiently perform a drilling operation or the like. Such a reciprocating tool includes a casing that is a tool body, a tip tool that is rotated by an electric motor provided in the casing, a motion conversion mechanism that converts rotational motion of the electric motor into reciprocating motion of the piston, and a piston. And a striking element for transmitting a striking force generated by the reciprocating motion to the tip tool. In this reciprocating tool, the casing vibrates due to the reciprocating motion of the piston, the operation of striking the tip tool with the striking element, the reaction of the striking element striking the object, and the like. Therefore, a technique for reducing the vibration of the casing in the reciprocating tool has been proposed, and an example thereof is described in Patent Document 1.

  The reciprocating tool described in Patent Document 1 is provided with a plurality of cylindrical weights arranged concentrically around a guide bar, and vibrations are reduced by installing the same number of springs as the number of weights on both sides of each weight. A mechanism (also referred to as a dynamic vibration absorber) is provided in the vibration direction.

JP 52-109673 A

  In the reciprocating tool, in order to suppress the occurrence of vibration, the period of vibration generation, that is, the period of reciprocation of the piston during the drilling operation, the spring constant, etc. It is desirable to set

  However, when the voltage fluctuates from, for example, 100 V to 120 V due to variations in the power source and is temporarily operated at a high voltage, the impact frequency of the reciprocating tool increases, and the weight vibrates in the high amplitude region accordingly. Become. Due to the vibration of the weight in the high amplitude region, a large load is applied to the spring and the like, and the durability of the reciprocating tool is lowered. In addition, it is necessary to secure a space for avoiding the contact of the weight with the tool body, resulting in an increase in size of the reciprocating tool.

  Therefore, the object of the present invention is to suppress the increase in the amplitude of the vibration reduction mechanism even if the voltage temporarily increases due to variations in the power source or the like and the impact frequency increases, thereby improving durability and An object of the present invention is to provide a reciprocating tool that can be miniaturized.

  The present invention includes a reciprocating motion converting unit that converts the rotation of the motor into a reciprocating motion of the tool, and a vibration reducing mechanism that reduces vibration due to the operation of the reciprocating motion converting unit, and the vibration reducing mechanism is disposed in the casing. A plurality of disposed weights, a coil spring provided at both ends of each of the weights, and biasing each weight so as to vibrate in the axial direction of the casing, and the amplitude of one weight exceeds a predetermined amplitude And a reciprocating tool in contact with the other weight.

  The plurality of weights are preferably arranged concentrically around the guide bar in the casing.

  The plurality of weights preferably have different weights.

  The plurality of weights are composed of an inner weight and an outer weight that is lighter than the inner weight, and the outer weight is provided with a restricting portion that contacts the inner weight when the amplitude of the inner weight exceeds a predetermined amplitude. It is preferable that

  The length of the outer weight in the axial direction is preferably longer than the length of the inner weight.

  It is preferable that a spring constant of the coil spring that biases the outer weight is larger than a spring constant of the coil spring that biases the inner weight.

  According to the present invention, even if the voltage temporarily increases due to variations in the power supply, etc., and the impact frequency is increased, the amplitude of the vibration reduction mechanism can be suppressed from increasing, and durability can be improved and downsized. A reciprocating tool capable of achieving the above can be provided.

It is a longitudinal cross-sectional view which shows the reciprocating tool which is embodiment of this invention. It is an expanded sectional view of the X section of FIG. It is an expanded sectional view of the Y section of FIG. It is a graph explaining the vibration reduction effect of the reciprocating tool of this embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. A reciprocating tool 10 shown in FIG. 1 is, for example, a hammer drill. That is, the reciprocating tool 10 transmits the power of the electric motor 11 to a tool (referred to as a tip tool) 12 having the tip of the reciprocating tool 10 to rotate the tip tool 12 and the rotation of the electric motor 11. It has a function of converting a force into a reciprocating motion and applying a striking force to the tip tool 12.

  The reciprocating tool 10 has a casing 13, and the casing 13 has a housing 14 and a gear cover 15. The housing 14 includes a cylindrical body portion 14a and a handle portion 14b continuous with one end of the body portion 14a. The handle portion 14b is a place where an operator who uses the reciprocating tool 10 grips it by hand.

  An opening end of the body portion 14a opposite to the handle portion 14b and one opening end of the gear cover 15 are connected via a holding member 47, and the housing 14 and the gear cover 15 are fixed by a fastening member. The fastening member is not shown for convenience. The holding member 47 constitutes a casing of the vibration reduction mechanism 49 with the inner cover 16.

  The gear cover 15 is configured in a cylindrical shape, and an inner cover 16 is provided inside the gear cover 15. The inner cover 16 is made of a metal material having excellent thermal conductivity, such as aluminum. The inside of the casing 13 includes a first housing chamber 17 formed in the body portion 14 a by the holding member 47 and the inner cover 16, a second housing chamber 18 formed in the gear cover 15, and the holding member 47. It is partitioned off from a third storage chamber 50 formed inside. That is, the inner cover 16 and the holding member 47 have a role of a partition wall.

  The electric motor 11 is provided in the first storage chamber 17. The electric motor 11 includes a stator 19 fixed to the housing 14 and a rotor 20 that is rotatably provided. The rotor 20 is rotatable about the axis A, and the stator 19 is disposed outside the rotor 20 in the radial direction about the axis A. The axis A is arranged along the horizontal direction in FIG. 1 for convenience. Further, the rotor 20 has an output shaft 21 and a coil 22 attached to the output shaft 21. An output gear 23 is formed on the outer peripheral surface of the output shaft 21.

  The inner cover 16 has an outer cylinder part 16a and an inner cylinder part 16b provided coaxially with the outer cylinder part 16a. The inner cylinder part 16b is provided inside the outer cylinder part 16a. An O-ring 15 a as a sealing device is interposed between the outer peripheral surface of the inner cover 16 and the inner peripheral surface of the gear cover 15. Furthermore, the inner cover 16 has an overhanging portion 16c that connects the end portion of the outer cylinder portion 16a and the end portion of the inner cylinder portion 16b in the direction along the axis A. The overhanging portion 16c extends in the radial direction about the axis A. The inner cylinder part 16b has a cylindrical shape, and a bearing 24 is attached to the inner peripheral surface of the inner cylinder part 16b. An O-ring (not shown) as a sealing device is attached between the inner peripheral surface of the inner cylinder portion 16 b and the outer ring of the bearing 24. The bearing 24 is a sealed bearing in which a sealing device (not shown) is attached between the inner ring and the outer ring.

  Further, a bearing (not shown) is provided at a location near the handle portion 14b in the first storage chamber 17. The bearing and the bearing 24 are arranged on the same axis, and the output shaft 21 is supported by two bearings so as to be rotatable about the axis A. Thus, two bearings are arranged at two different locations in the direction along the axis A. One end of the output shaft 21 is disposed in the second storage chamber 18, and the output gear 23 is provided in a portion of the output shaft 21 disposed in the second storage chamber 18.

  The first storage chamber 17 is provided with a brush (not shown) that supplies power to the coil 22. A power cord 25 is attached to the handle portion 14b, and the power cord 25 is connected to an external power source (not shown). The handle portion 14b is provided with a trigger 26 that is a power switch, and a control circuit (not shown) is provided inside the handle portion 14b. This control circuit performs control to supply power supplied via the power cord 25 to the brush. In the electric motor 11, when the trigger 26 is operated, electric power is supplied to the coil 22 via the power cord 25, a rotating magnetic field is formed between the rotor 20 and the stator 19, and the rotor 20 rotates.

  A fan 27 is provided between the coil 22 and the inner cover 16 in the direction along the axis A in the first storage chamber 17. The fan 27 is a mechanism for forming a flow of air that cools the interior of the electric motor 11 and the second storage chamber 18, and the fan 27 of the present embodiment is configured by a centrifugal fan. The fan 27 has an impeller 27a attached to the output shaft 21 and a guide wall 27b surrounding the outer peripheral side of the impeller 27a.

  The guide wall 27 b is provided between the stator 19 and the inner cover 16 in the direction along the axis A. The guide wall 27 b is fixed so as not to rotate with respect to the housing 14. The fan 27 has an intake passage 27c formed between the impeller 27a and the guide wall 27b. The intake passage 27c is formed from the inside to the outside in the radial direction with the axis A as the center.

  In addition, a vent hole 28 that communicates the inside and the outside of the casing 13 is provided at, for example, a coupling portion between the housing 14 and the gear cover 15 on the outer peripheral side of the impeller 27a. The vent hole 28 is provided to discharge the air guided by the fan 27 to the outside of the casing 13. The ventilation holes 28 are provided at two locations on the side and the lower side of the casing 13. The guide wall 27b is opened at two locations facing the vent hole 28 in the circumferential direction about the axis A.

  An intermediate shaft 29 is provided in the second storage chamber 18. The intermediate shaft 29 is a power transmission element that transmits the power of the output shaft 21 to the tip tool 12. Two bearings 30 a and 30 b are coaxially provided in the second storage chamber 18. The intermediate shaft 29 is supported by two bearings 30a and 30b so as to be rotatable about the center line B. The two bearings 30 a and 30 b are attached to the gear cover 15. The center line B is parallel to the axis A, and the center line B is arranged non-coaxially with the axis A. A gear 31 is provided at the end of the intermediate shaft 29 that is closer to the overhanging portion 16c. The gear 31 is meshed with the output gear 23. Further, a gear 32 is formed between the two bearings 30a and 30b in the intermediate shaft 29.

  Further, a cylinder 33 is provided in the second storage chamber 18. The cylinder 33 is an element that transmits the torque of the intermediate shaft 29 to the tip tool 12. The cylinder 33 includes a large-diameter cylindrical portion 34 and a small-diameter cylindrical portion 35 that are provided coaxially about the center line C. The inner diameter of the large diameter cylindrical portion 34 is larger than the inner diameter of the small diameter cylindrical portion 35. A third gear 36 is attached to the outer peripheral surface of the large diameter cylindrical portion 34. The third gear 36 is provided so as to rotate integrally with the cylinder 33, and the third gear 36 and the gear 32 are engaged with each other. The gear 32 and the third gear 36 are elements that transmit the torque of the intermediate shaft 29 to the cylinder 33.

  The gear cover 15 has a cylindrical portion 37 at a location opposite to the housing 14 in the direction along the axis A. The inner diameter of the cylindrical portion 37 is larger than the outer diameter of the large diameter cylindrical portion 34 and the outer diameter of the small diameter cylindrical portion 35. A grip portion 60 is attached to the outer peripheral surface of the cylindrical portion 37, and a bearing 38 is attached to the inner peripheral surface of the cylindrical portion 37. A bearing 39 is attached to the inner peripheral surface of the inner cover 16. The two bearings 38 and 39 are arranged coaxially, and the large-diameter cylindrical portion 34 is rotatably supported by the bearing 39. The small diameter cylindrical portion 35 is rotatably supported by a bearing 38. That is, the cylinder 33 can rotate around the center line C by the two bearings 38 and 39. The center line C is parallel to the axis A and the center line B, and the center line C is non-coaxial with the axis A and the center line B.

  1 is a longitudinal sectional view including a center line C. In FIG. 1, the axis A is located below the center line C, and the center line B is located below the axis A. FIG. The first center line A that is an axis, the second center line B that is a center line, and the third center line C are all parallel. The first center line A, the second center line B, and the third center line C may all be located on the same plane, or only two center lines are located on the same plane. Also good.

  The cylinder 33 is positioned and fixed in a direction along the center line C with respect to the gear cover 15. Further, a sealing device 56 is provided between the cylindrical portion 37 and the small diameter cylindrical portion 35. The sealing device 56 is configured by a known oil seal or the like, and the sealing device 56 is for preventing the lubricating oil sealed in the second storage chamber 18 from leaking to the outside of the casing 13. is there.

  The tip of the small diameter cylindrical part 35 is exposed to the outside of the cylindrical part 37. The tip tool 12 is inserted into the small diameter cylindrical portion 35. The outer peripheral surface of the tip tool 12 has a length in the direction along the center line C. A groove 12a is provided. On the other hand, a holding hole 35a penetrating the small-diameter cylindrical portion 35 in the radial direction is provided, and a ball 55 is disposed in the holding hole 35a. An end cover 40 is attached to a portion of the small-diameter cylindrical portion 35 that is exposed to the outside of the cylindrical portion 37.

  The end cover 40 is configured so as to rotate integrally with the cylinder 33. The end cover 40 includes a pressing member 40a that prevents the ball 55 from dropping from the holding hole 35a. A part of the ball 55 held in the holding hole 35a is disposed in the groove 12a. That is, the ball 55 can roll in the groove 12a. The cylinder 33 and the tip tool 12 are prevented from rotating relative to each other by the engaging force of the ball 55. That is, the torque of the cylinder 33 is transmitted to the tip tool 12 via the ball 55, and the tip tool 12 rotates.

  Further, the tip tool 12 is movable in the direction along the center line C with respect to the cylinder 33 based on the length of the groove 12a in the direction along the center line C. The end cover 40 is configured to be attachable to and detachable from the cylinder 33. When the end cover 40 is operated, the ball 55 comes out of the holding hole 35a, so that the tip tool 12 can be replaced.

  A piston 41 as an operation member is inserted into the large diameter cylindrical portion 34. The piston 41 is movable in the direction along the center line C within the large diameter cylindrical portion 34. The piston 41 has a cylindrical portion 41a and a bottom portion 41b formed continuously with the cylindrical portion 41a. The opening part of the cylindrical part 41a is arrange | positioned at the small diameter cylindrical part 35 side. The cylindrical portion 41a is provided with a vent hole 41c penetrating in the radial direction, and a striker 42 is inserted into the cylindrical portion 41a. The striker 42 is movable in the direction along the center line C with respect to the piston 41, and a pneumatic chamber 43 is formed between the striker 42 and the bottom 41b in the cylindrical portion 41a. The volume of the pneumatic chamber 43 is set so that the striking force generated by the reciprocating motion of the piston 41 becomes a target value. An O-ring 42 a is attached to the outer peripheral surface of the striker 42, and the O-ring 42 a maintains an airtight space between the striker 42 and the large diameter cylindrical portion 34.

  In the cylinder 33, an intermediate element 44 is provided between the striker 42 and the tip tool 12. That is, the intermediate element 44 is disposed between the striker 42 and the tip tool 12 in the direction along the center line C, and the intermediate element 44 is movable in the direction along the center line C with respect to the cylinder 33. . The intermediate element 44 is an element that transmits the striking force applied to the striking element 42 by the pressure increase in the pneumatic chamber 43 to the tip tool 12. The intermediate element 44 can contact or move away from the striker 42 and the tip tool 12.

  On the other hand, the second storage chamber 18 is provided with a motion conversion mechanism 45 that converts the rotational motion of the intermediate shaft 29 into the reciprocating motion of the piston 41. The motion conversion mechanism 45 has an inner ring 45a and an outer ring 45b. The inner ring 45 a is attached to the outer peripheral surface of the intermediate shaft 29. The inner ring 45a is rotatable relative to the intermediate shaft 29. The outer peripheral surface of the inner ring 45a has an arc shape in a plane including the center line B, and a groove (not shown) is formed on the outer peripheral surface of the inner ring 45a. Corresponding to the phase change in the circumferential direction of the inner ring 45a, the position of the groove in the direction along the center line B is different. A plurality of rolling elements 45c are interposed in the circumferential direction between the outer ring 45b and the inner ring 45a. The rolling element 45c can roll along the groove. The outer ring 45b is provided with a connecting rod 45d, and the connecting rod 45d is connected to the piston 41. For this reason, the outer ring 45b does not rotate around the center line B.

  Furthermore, a clutch 46 is provided in the second storage chamber 18. The clutch 46 is a mechanism for connecting and disconnecting a power transmission path between the inner ring 45a and the intermediate shaft 29. The clutch 46 rotates integrally with the intermediate shaft 29 and is movable in the direction along the center line B with respect to the intermediate shaft 29. When the clutch 46 moves toward the left side along the center line B and stops, the power transmission path between the intermediate shaft 29 and the inner ring 45a is connected. That is, the clutch 46 is engaged. In contrast, when the clutch 46 moves toward the right side along the center line B and stops, the power transmission path between the intermediate shaft 29 and the inner ring 45a is interrupted. That is, the clutch 46 is released. The movement, stop, and moving direction of the clutch 46 in the direction along the center line B are switched by the operator operating the mode switch 48. The mode switch 48 is provided on the outer surface of the casing 13.

  The vibration reduction mechanism 49 is provided in the third storage chamber 50 as shown in FIGS. In the embodiment, the vibration reduction mechanism 49 includes at least two cylindrical weights 52 and 53 having different weights arranged concentrically around the guide bar 51 in the third storage chamber 50 in the casing 13, and the inside of the casing 13. Coil springs provided at both ends of the respective weights 52 and 53 and biasing the respective weights 52 and 53 so as to vibrate in the direction of the axis A of the casing 13 (coil springs 54 and 55 biasing one weight 52 and the other) Coil springs 57, 58) for urging the weight 53, and a restricting portion 59 that contacts the other weight 53 and suppresses the amplitude of the one weight 52 when the amplitude of one weight 52 is large and exceeds a predetermined amplitude. doing.

  The guide bar 51 is formed in a shaft shape with a circular cross section, and constitutes the output shaft 21 of the electric motor 11. One weight 52 is formed in an annular shape, and the guide bar 51 is loosely inserted into the shaft hole 52a. The other weight 53 is formed in a cylindrical shape, and is loosely fitted in the shaft hole 53a so as to be movable in the axial direction while the one weight 52 is loosely inserted. The weight of the other weight 53 is set to be lighter than the weight of the one weight 52. The spring constants of the coil springs 54 and 55 that bias one weight 52 are set lower than the spring constants of the coil springs 57 and 58 that bias the other weight 53. The natural frequency determined by one weight 52 and coil springs 54 and 55 is preferably substantially the same as the natural frequency determined by the other weight 53 and coil springs 57 and 58. Further, it is preferable that the amplitude of one weight 52 when vibrating at the same frequency is larger than the amplitude of the other weight 53. The other weight 53 is formed to be longer in the axial direction than the one weight 52, and an annular regulating portion 59 is provided on the inner circumference of both end portions in the longitudinal direction. The inner diameter of the restricting portion 59 is smaller than the outer diameter of the one weight 52, thereby restricting the axial movement range of the one weight 52 to a predetermined range. As a result, the vibration range in the axial direction of one weight 52 is limited to a predetermined range, and even if the voltage temporarily increases due to variations in power supply or the like and the striking frequency increases, the amplitude of the vibration reduction mechanism increases. It comes to suppress becoming. The predetermined amplitude and the predetermined range here are the characteristics of the low vibration mechanism (particularly one weight 52, the other weight 53, the coil springs 54 and 55, and the coil springs 57 and 58) and the impact characteristics of the impact tool (particularly The value is generally determined by the hitting frequency), but does not necessarily mean a constant value.

  The operation of the reciprocating tool 10 configured as described above will be described. First, the operator grasps the handle portion 14b with one hand, grasps the grip portion 60 with the other hand, presses the tip tool 12 against the object, and pulls the trigger 26. Then, electric power is supplied to the electric motor 11 to rotate the rotor 20, and the torque of the output shaft 21 is transmitted to the intermediate shaft 29 via the guide bar 51, the output gear 23, and the gear 31. The torque of the intermediate shaft 29 is transmitted to the cylinder 33 via the gear 32 and the third gear 36. The torque of the cylinder 33 is transmitted to the tip tool 12 via the ball 55.

  During the above operation, when the mode changeover switch 48 is operated and the driver mode is selected, the clutch 46 is released. For this reason, the rotational motion of the intermediate shaft 29 is not converted into the reciprocating motion of the piston 41. Accordingly, no striking force is applied to the tip tool 12. On the other hand, when the mode changeover switch 48 is operated and the hammer driver mode is selected, the clutch 46 is engaged. For this reason, the rotational motion of the intermediate shaft 29 is converted into the reciprocating motion of the piston 41. When the sealing member of the striker 42 is positioned closer to the tip tool 12 than the vent hole 41c, the pneumatic chamber 43 communicates with the outside of the piston 41 through the vent hole 41c.

  When the tip tool 12 is pressed against the work material, the striker 42 moves to the left in FIG. Then, the vent hole 41 c is closed by the striker 42. Next, when the piston 41 moves to the right in FIG. 1, the pressure in the pneumatic chamber 43 rises and a striking force is generated. The generated striking force is transmitted to the tip tool 12 via the striking element 42 and the intermediate element 44. Therefore, the tip tool 12 is hit while rotating. When the striker 42 moves to the right in FIG. 1, the vent hole 41c is opened, the air pressure chamber 43 communicates with the atmosphere, and the pressure decreases. Accordingly, the striking force is reduced and the striker 42 stops. Thereafter, the above action is repeated as the piston 41 reciprocates.

  A vibration reduction mechanism 49 is provided in the casing 13 at least two weights 52 and 53 having different weights disposed concentrically around the guide bar 51, and both ends of the weights 52 and 53 in the casing 13, respectively. When the amplitude of the coil spring 54 that urges the weights 52 and 53 to vibrate in the axial direction of the casing 13 and the inner weight 52 exceeds a predetermined amplitude, the amplitude of one weight 52 is suppressed by contacting the outer weight 53. Since the regulation portions 59 and 59 are included, the amplitude of the inner weight 52 in the vibration reduction mechanism 49 is increased even if the voltage temporarily increases due to variations in the power source or the like and the impact frequency increases. Can be suppressed.

  This function and effect will be described with reference to FIG. 4. A conventional dynamic vibration absorber (vibration reduction mechanism) is provided. In the case of a reciprocating tool, since one weight and the other weight vibrate independently, the amplitude of the dynamic vibration absorber becomes large (high) as shown by the broken line, which may cause damage to the coil spring. However, according to the reciprocating tool of this embodiment, it can be seen that the amplitude of the dynamic vibration absorber can be reduced as indicated by the solid line, and the durability can be improved. In FIG. 4, the weight (A) is the case of only the weight 53, and the weight (B) is the case of the weight 53 and the weight 52.

  Thereby, the phenomenon that the inner weight 52 vibrates more than necessary can be suppressed, and the damage of the coil spring 54 of the inner weight 52 and the damage of the components due to the collision of the inner weight 52 can be suppressed. In addition, the space for avoiding the collision can be reduced, and the durability can be improved and the size can be reduced.

  In addition, the weight includes an inner weight 52 and an outer weight 53 that is lighter than the inner weight 52. The outer weight 53 is provided with a restricting portion 59, and the axial length of the outer weight 53 is Since it is longer than the length of the inner weight 52, the weight can be made compact, and the reciprocating tool can be reduced in size and weight. Further, since the spring constant of the coil spring 55 of the outer weight 53 is larger than the spring constant of the coil spring 54 of the inner weight 52, even if a load of the inner weight 52 is applied to the outer weight 53, the coil spring of the outer weight 53. 55 can sufficiently withstand and improve durability.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the reciprocating tool only needs to be able to apply a striking force to the tip tool, and the reciprocating tool may be configured such that the tip tool cannot rotate. In addition, the reciprocating tool may be configured to be able to switch between three types: a hammer dedicated mode, a drill dedicated mode, and a hammer drill mode. The hammer-only mode is a mode that gives only the striking force to the tip tool, the drill-only mode is a mode that gives only the turning force to the tip tool, and the hammer drill mode is a mode that gives the striking force and turning force to the tip tool. is there. Further, the tip tool may be a driver bit for tightening the screw member. Furthermore, the tip tool may be a drill bit for drilling and crushing concrete, stone or the like.

  Further, the fan provided in the casing may be an axial fan. The air guide path provided in the weight includes notches, grooves and the like in addition to holes. In addition, the reciprocating tool should be used in any of the two centerlines and axes along the vertical direction, along the horizontal direction, or between the horizontal and vertical directions. You can also. Furthermore, the center of gravity of the reciprocating tool can be used as a reference for analyzing the vibration of the casing, instead of the center of gravity of the casing. The center of gravity of the reciprocating tool is the center of the total mass of the mass of the casing and the mass of components, mechanisms, elements, etc. provided in the casing. Furthermore, the reciprocating tool may have a structure in which a battery for supplying electric power to the electric motor is accommodated in the casing, or a structure in which the battery is attached to the casing in a cassette structure. Further, the number and size of the second leaf springs in the vibration reduction mechanism can be changed as appropriate.

DESCRIPTION OF SYMBOLS 10 Reciprocating tool 11 Electric motor 12 Tip tool 13 Casing 45 Motion conversion mechanism 49 Vibration reduction mechanism 51 Guide bar 52, 53 Weight 52 Inner weight 53 Outer weight 54, 55 Coil spring 59 Restriction part

Claims (6)

A reciprocating motion converter for converting the rotation of the motor into the reciprocating motion of the tool;
A vibration reduction mechanism for reducing vibration due to the operation of the reciprocating motion conversion unit,
The vibration reducing mechanism is
A plurality of weights arranged in the casing;
A coil spring provided at both ends of each of the weights and biasing each weight so as to vibrate in the axial direction of the casing;
A reciprocating tool that contacts the other weight when the amplitude of one weight exceeds a predetermined amplitude. The reciprocating tool according to claim 1,
The plurality of weights are reciprocating tools arranged concentrically around a guide bar in a casing. The reciprocating tool according to claim 1,
The plurality of weights are reciprocating tools whose weights are different from each other. The reciprocating tool according to claim 2, wherein
The plurality of weights are composed of an inner weight and an outer weight that is lighter than the inner weight, and the outer weight is provided with a restricting portion that contacts the inner weight when the amplitude of the inner weight exceeds a predetermined amplitude. A reciprocating tool. The reciprocating tool according to claim 4, wherein
A reciprocating tool in which an axial length of the outer weight is longer than a length of the inner weight. The reciprocating tool according to claim 4, wherein
A reciprocating tool, wherein a spring constant of the coil spring that biases the outer weight is larger than a spring constant of the coil spring that biases the inner weight.

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