JP5674027B2 - Tightening tool - Google Patents

Description

  The present invention relates to a tightening tool, and more particularly to a tightening tool for tightening a screw with a tip tool.

  Conventionally, tightening tools as so-called impact tools for tightening screws such as nuts and bolts are known. As an impact tool, one having a configuration in which a striking force is transmitted to an output shaft in a rotational direction by a rotational impact force of a hammer is known. The impact tool having this configuration includes a motor, a hammer, and an anvil.

  In an impact tool, a motor installed in a housing is driven using electric power supplied from a rechargeable battery or electric power supplied from the outside by a power cord, and the motor is driven through a reduction mechanism. Rotate the spindle. Then, tightening is performed by striking the anvil with a hammer that is rotatable on the spindle and movable in the axial direction via a steel ball inserted into a cam groove formed on the spindle.

  The hammer is pushed forward by a spring arranged between the speed reduction mechanism and the spindle, and if the rotational resistance increases after the screw is seated, the rotation of the anvil is suppressed, and the hammer gets over the hammer collision part of the anvil. Accelerate and hit the anvil again. In this manner, several to ten and several times of rotational impact force is transmitted continuously or intermittently to a tip tool (not shown) such as a hexagon socket, and operations such as nut tightening and bolt tightening are performed. Such a tightening tool is described in, for example, JP 2010-058186 A (Patent Document 1).

JP 2010-058186 A

  However, with a tightening tool of this configuration, the hammer and anvil are generally made of metal, so the impact effect is great, but the noise at the time of collision is very large, and it can be used in environments where low noise is required. It becomes difficult. Here, the noise reduction means to reduce the sound generated at the time of one hit and to reduce the number of times the sound is generated by reducing the number of hits as much as possible.

  In the case of reducing the number of hits, for example, if a motor having a configuration in which a motor and a tip tool are connected via a reduction mechanism is used, screwing can be performed with one hit. However, the tightening torque is less than or equal to one-tenth for an impact tool using the same motor, and the reaction transmitted to the hand becomes very large, which is dangerous. Further, in the case of a general cordless oil pulse tool, the danger is smaller than that of an impact tool, but the reaction that is transmitted to the hand at the time of bolt tightening is still a burden during continuous work.

  Therefore, an object of the present invention is to provide a tightening tool that can tighten a bolt or a screw with a very small impact sound and can be fastened with a single impact, and has a small reaction.

  In order to achieve the above object, the present invention includes a motor, a weight that is rotated by the motor and can store rotational energy, and a tool mounting portion that can be connected to the weight and on which a tip tool is mounted. An output shaft portion, and the weight and the output shaft portion are configured to be capable of transmitting rotational energy to the output shaft portion in a state in which the weight rotates one or more times around the shaft of the weight. Provides tools.

  According to such a configuration, since the weight can rotate more than one turn, the rotational energy can be stored sufficiently. By transmitting this rotational energy to the output shaft portion, the striking force output from the output shaft portion can be reduced. Can be bigger.

  In the tightening tool having the above-described configuration, it is preferable that the motor is directly connected to the weight, and the output shaft portion is configured to be directly connectable to the weight after the weight has rotated one or more rounds.

  According to such a configuration, there is no speed change mechanism or the like between the motor and the weight and between the weight and the output shaft portion. Therefore, the weight is attached to the motor, the weight, the housing that comprehensively holds the output shaft portion, or the like. The transmission of the reaction force accompanying the rotation of the output shaft portion is suppressed, and the reaction transmitted to the hand can be suppressed as much as possible.

  The apparatus further comprises a control device for detecting the current flowing to the motor and controlling the rotation of the motor, the control device comprising a rotation speed control means for controlling the rotation speed of the motor to a constant rotation speed after the motor is started. It is preferable to provide at least one or both of motor stop means for stopping the rotation of the motor when the current flowing through the motor reaches a specified value.

  According to such a configuration, after seating is completed after tightening the fastening tool tightened by the tip tool held by the tip tool holding portion, the motor rotation is stopped or the motor rotation number is reduced, and power is wasted. Can be prevented.

  Further, the weight is composed of a plurality of rotating bodies that are arranged in the axial direction of the weight and are rotatable about the shaft as a rotation axis, and the plurality of rotating bodies are positioned on one end side in the axial direction. Can be connected to the output shaft portion, and the rotating body located at the other end side is driven to rotate by the motor, and each rotating body has its own rotating body adjacent to each rotating body. It is preferable to provide a contact portion that contacts the adjacent rotating body when rotated to near 360 °.

  According to such a configuration, the rotating body is gradually rotated from the rotating body close to the motor, and the rotational force is transmitted to the output shaft portion. When the rotational force is transmitted to the output shaft portion, the rotating body that is not adjacent to the output shaft portion rotates a plurality of times, so that the rotational energy that has rotated more than one turn is accumulated for the entire weight, and this rotational energy is stored in the output shaft. By transmitting to the part, a suitable striking force can be applied to the output shaft part.

  The control device further includes a control device that controls the rotation of the motor, and a switch that outputs a signal to the control device. The control device receives the signal from the switch in a state where the motor is stopped. It is preferable to have a motor rotating means for rotating the motor so that the rotating body positioned on the end side rotates to at least about 360 ° with respect to the adjacent rotating body.

  According to such a configuration, it is possible to create a state in which the contact portion of one rotating body is separated from the adjacent rotating body, and a state in which the weight is connected to the output shaft portion with each rotating body rotating. Can be produced.

  The control device further includes a control device that controls the rotation of the motor, and the control device is a rotation positioned on the other end side in the axial direction when starting the motor from a stopped state and rotating the weight to one side around the shaft. When rotating the motor to rotate the motor to rotate the weight to the one side after rotating the motor so that the body rotates to the other side around the axis to at least 360 ° with respect to the adjacent rotating body When the motor is stopped from the rotating state where the weight is rotated to the one side, the rotating body positioned on the other end side in the axial direction is at least about 360 ° around the axis with respect to the adjacent rotating body. You may have at least one means of the motor stop reversing means which stops this motor after rotating this motor so that it may rotate to the other side.

  The control device further includes a control device that controls rotation of the motor, and a changeover switch that outputs a signal for switching forward / reverse rotation of the motor to the control device, and the control device receives a switching signal from the changeover switch. At the time of input, at least 360 in a direction opposite to the direction in which the motor rotates based on the signal input from the change-over switch with respect to a rotating body adjacent to the rotating body located on one axial end side. A motor switching reversing means for rotating the motor so as to rotate to the vicinity of ° may be provided.

  According to such a configuration, when the motor is stopped, when the motor starts rotating, and when the rotation of the motor is switched, the contact portion of one rotating body is separated from the adjacent rotating body. Can be produced.

  The output shaft portion further includes a holding portion that can rotate around the rotation shaft of the output shaft portion and can slide in a direction parallel to the rotation shaft, and the output shaft portion and the weight are coaxial. It is preferable to include abutting portions that are disposed above and that can abut against each other only when the output shaft portion slides toward the weight side.

  According to such a configuration, the rotational energy stored in the weight can be transmitted to the output shaft portion by connecting the weight and the output shaft portion in a state where the weight is rotated a plurality of times.

  As described above, the present invention can provide a tightening tool that has a very low impact sound and that can fasten bolts and screws with a single impact and that has a small reaction.

Sectional drawing which shows the clamping tool by 1st embodiment of this invention. The front view which shows the front-end part of the output shaft of the motor of the clamping tool by 1st embodiment of this invention. The figure which shows the weight of the clamping tool by 1st embodiment of this invention. Sectional drawing along the IV-IV line of FIG. Sectional drawing along the VV line of FIG. Sectional drawing which shows the state which cannot accumulate | store rotational energy in a weight in the clamping tool by 1st embodiment of this invention. Sectional drawing which shows the state which can accumulate | store rotational energy in a weight in the clamping tool by 1st embodiment of this invention. The flowchart which shows operation | movement of the clamping tool by 1st embodiment of this invention, and control of a control apparatus. The graph which shows the relationship between the electric current value of the motor, torque, and rotational speed in the clamping tool by 1st embodiment of this invention. Sectional drawing which shows the example of the clamping tool by 2nd embodiment of this invention.

  A first embodiment of a tightening tool according to the present invention will be described with reference to FIGS. 1 to 5. As shown in FIG. 1, the tightening tool 1 is specifically a tightening tool for tightening a screw that is a bolt or a nut, and includes a housing 10, a motor 30, a weight 40, and an anvil 50. doing. These “nuts” and “bolts” mean that the load for rotating is hardly applied at the start of tightening, and the load is suddenly increased immediately after the tightening is completed.

  The housing 10 includes a body housing part 11 and a handle housing part 12, and the body housing part 11 and the handle housing part 12 are integrally formed of resin and are integrally connected to each other. The body housing part 11 has a cylindrical shape, and the motor 30 and the weight 40 are arranged side by side in the body housing part 11. In the following description, the side on which the weight 40 is disposed with respect to the motor 30 is defined as the front side, and the side on which the motor 30 is disposed with respect to the weight 40 is defined as the rear side. Further, the description will be made by defining the vertical direction with the direction perpendicular to the front-rear direction and extending the handle housing part 12 from the body housing part 11 as the downward direction.

  The handle housing portion 12 incorporates a control device 15 and a storage device (not shown), and a trigger 13 is provided at the upper end portion of the handle housing portion 12. A storage device (not shown) stores in advance an upper limit value of the current flowing through the motor 30 when the screw is seated as will be described later. A rechargeable battery 14 is detachably attached to the handle housing portion 12 at the lower end portion of the handle housing portion 12. The battery 14 can supply power to the motor 30 and the control device 15. The control device 15 is configured to supply electric power to the motor 30 when the trigger 13 is operated by an operator.

  An operation unit (not shown) capable of setting the number of rotations of the motor 30, a current value flowing through the motor 30, and the like is provided outside the body housing unit 11, and the operation unit is provided with a motor reversing switch described later. ing. Further, a changeover switch (not shown) for switching the rotation direction of the motor 30 is disposed in the vicinity of the trigger 13 in the body housing portion 11. An operation unit (not shown) and a changeover switch (not shown) are electrically connected to the control device 15.

  The motor reversing switch is a switch that rotates the motor 30 by a predetermined angle in the direction opposite to the rotation direction defined by the changeover switch. That is, when the changeover switch stipulates that the motor 30 rotates clockwise, the motor 30 can be rotated a predetermined angle counterclockwise by operating the motor reverse switch.

  Further, an inner cover 36 is provided in a portion of the body housing portion 11 that accommodates a weight 40 described later. A metal bearing 37 is provided at the rear of the inner cover 36. The metal bearing 37 rotatably supports a rear end portion of a first rotating body 41 described later.

  A hammer case 38 is connected to the front side of the inner cover 36, and the inner cover 36 and the hammer case 38 define a space for accommodating the weight 40. The front end of the hammer case 38 is open, and a metal bearing 39 is provided in the opening. The metal bearing 39 supports the anvil 50 in a rotatable manner. A seal member (not shown) is interposed between the inner cover 36 and the hammer case 38. The seal member (not shown) leaks internal lubricating oil between the inner cover 36 and the hammer case 38. It is sealed so that there is no.

  The motor 30 is a brushless motor, and includes a current detection device (not shown) that can detect a current flowing through the motor 30. A current detection device (not shown) is electrically connected to the control device 15, and the control device 15 can detect a current value. The motor 30 includes a rotating shaft portion 31 that extends in the front-rear direction. The rotary shaft portion 31 has a rear end and a front end supported by the body housing portion 11 via bearings 32 and 32, and is configured to be rotatable with respect to the body housing portion 11. The motor 30 is configured to be able to rotate the rotating shaft portion 31 at a maximum of 500 rad / s. A fan 33 is fixed at the rear position of the front bearing 32 in the rotary shaft portion 31 so as to rotate integrally with the rotary shaft portion 31. Further, a weight engaging portion 34 is provided at a front position of the front bearing 32 in the rotating shaft portion 31.

  As shown in FIG. 2, the weight engaging portion 34 has a pair of sides 34A parallel in a plan view perpendicular to the front-rear direction and a pair of arcs 34B respectively connecting the ends of the pair of sides 34A. The rotary shaft portion 31 is fixed to the axial center position so as to rotate coaxially and integrally.

  The weight 40 is disposed in a space defined by the inner cover 36 and the hammer case 38, and is mainly composed of four first rotating bodies 41 to fourth rotating bodies 44 and a mandrel 45. . The four first rotating bodies 41 to the fourth rotating body 44 are each disk-shaped with the same diameter so that the first rotating body 41 is located at the rearmost position and the fourth rotating body 44 is located at the foremost position. Arranged from the rear to the front, each disk is rotatably arranged so that the axial direction of each disk coincides with and is coaxial with the front-rear direction and each disk is parallel.

  The first rotating body 41 is rotatably supported by the metal bearing 37 so that the metal bearing 37 is inserted around the outer periphery of the first rotating body 41. As shown in FIGS. 1 and 3, an engagement recess 41 a is formed on the rear surface of the first rotating body 41. The engaging recess 41a has the same shape as the weight engaging portion 34, and the weight engaging portion 34 is engaged with the engaging recess 41a so as to be coaxial.

  As shown in FIG. 4, the front inner circumferential convex portion 41 </ b> C that is a contact portion that protrudes toward the second rotating body 42 and can come into contact with the second rotating body 42 on the front surface of the first rotating body 41. And a front outer peripheral convex portion 41D. On the plane orthogonal to the front-rear direction, the front inner peripheral convex portion 41C and the front outer peripheral convex portion 41D are each formed in a sector shape having a central diameter of 60 ° and the same central diameter. It is located at a position shifted by 180 ° around the center and at a position where the rotation trajectories around the axis do not overlap. Further, both side surfaces in the circumferential direction of the front inner peripheral convex portion 41C and the front outer peripheral convex portion 41D have a planar shape perpendicular to the tangential direction around the axis of the first rotating body 41, and the axis of the first rotating body 41 It is configured to coincide with a plane including the center and extending in the radial direction.

  Further, the front surface of the first rotating body 41 is provided with a protrusion 41E that is disposed at the axial center position and protrudes to the front side from the front inner peripheral convex portion 41C and the front outer peripheral convex portion 41D. Is formed with a perforation 41b that is located on the axial center and opens to the front surface of the protrusion 41E.

  Since the 2nd rotary body 42-the 4th rotary body 44 are all comprised so that it may be arrange | positioned in the same shape and the same direction, the 2nd rotary body 42 is demonstrated as an example. As shown in FIGS. 3 and 4, the second rotating body 42 has its rear surface in contact with the protrusion 41 </ b> E of the first rotating body 41, and the position in the front-rear direction with respect to the first rotating body 41 is restricted. On the rear surface of the second rotating body 42, there are contact portions that protrude toward the first rotating body 41 and can contact the front inner peripheral convex portion 41 </ b> C and the front outer peripheral convex portion 41 </ b> D of the first rotating body 41. A certain rear surface inner peripheral convex portion 42A and a rear surface outer peripheral convex portion 42B are provided.

  The rear inner peripheral convex portion 42A and the rear outer peripheral convex portion 42B are each formed in a sector shape having a central diameter of 60 ° and the same central diameter, and are shifted by 180 ° around the axis of the second rotating body 42. In addition, it is arranged at a position where the trajectories of rotation around the axis do not overlap. One side surface and the other side surface in the circumferential direction of the rear inner circumferential convex portion 42A and the rear outer circumferential convex portion 42B have a planar shape orthogonal to the tangential direction, and include the axis of the second rotating body 42 in the radial direction. It is comprised so that it may correspond with the extended plane. Further, the distance from the axial center of the rear inner peripheral convex portion 42A is equal to the distance from the axial center of the first rotating body 41 to the front inner peripheral convex portion 41C, and the distance from the axial center of the rear outer peripheral convex portion 42B is. It is comprised so that it may become equal to the distance from the axial center of the 1st rotary body 41 to front surface outer peripheral side convex part 41D. That is, the rear inner peripheral convex portion 42A and the rear outer peripheral convex portion 42B have the same shape as the front inner peripheral convex portion 41C and the front outer peripheral convex portion 41D. Since the first rotator 41 and the second rotator 42 are rotatably arranged on the same axis as described above, the rear inner peripheral convex portion 42A and the rear outer peripheral convex portion 42B of the second rotary body 42 are provided. One side surface and the other side surface of the first rotating body 41 are in contact with the other side surface in the circumferential direction of the front inner peripheral convex portion 41C and the front outer peripheral convex portion 41D of the first rotating body 41 (FIG. 6). Up to the contact state (FIG. 7), that is, 240 ° (240 ° = 360 ° −60 °), which is an angle at which the second rotating body 42 is less than 360 ° and near 360 ° with respect to the first rotating body 41. × 2) Can rotate.

  As shown in FIGS. 3 and 5, the front inner peripheral side that is a contact portion that protrudes toward the third rotating body 43 side and can contact with the third rotating body 43 on the front surface of the second rotating body 42. A convex portion 42C and a front outer peripheral convex portion 42D are provided. The front inner peripheral convex part 42C and the front outer peripheral convex part 42D have the same shape as the front inner peripheral convex part 41C and the front outer peripheral convex part 41D of the first rotating body 41, and the rear inner peripheral part. The side convex portion 42A and the rear outer peripheral side convex portion 42B are arranged at positions shifted by 180 ° around the axis. The rear inner circumferential convex portion 42A, the rear outer circumferential convex portion 42B, the front inner circumferential convex portion 42C, and the front outer circumferential convex portion 42D are arranged at positions shifted by 180 °, so that the second rotating body 42 The center of gravity position can be set as the axial center position.

  Further, the front surface of the second rotating body 42 is provided with a projecting portion 42E that is disposed at the axial center position and projects forward from the front inner peripheral convex portion 42C and the front outer peripheral convex portion 42D. 42E can contact | abut to the 3rd rotary body 43, and the front-back direction distance between the 2nd rotary body 42 and the 3rd rotary body 43 can be prescribed | regulated. The projecting portion 42E is formed with a through hole 42a that is located on the axial center and opens to the front surface of the projecting portion 42E and the rear surface of the second rotating body 42, respectively. The through hole 42a is formed so that its inner diameter is the same as the inner diameter of the perforation 41b.

  Since the third rotating body 43 and the fourth rotating body 44 have the same shape as the second rotating body 42, the second rotating body 42 can rotate 240 ° with respect to the third rotating body 43. Is rotatable by 240 ° with respect to the fourth rotating body 44. Therefore, the first rotating body 41 can rotate 240 ° × 3 = 720 ° with respect to the fourth rotating body 44, and the second rotating body 42 can rotate with 240 ° × 2 = 480 ° with respect to the fourth rotating body 44. become.

Mandrel 45 has an outer diameter of round bar of slightly smaller diameter than the perforations 41b inner diameter, puncture hole 41b as shown in FIG. 3, the through hole 42a, the through hole 43a, the front end and inserted into the through hole 44a first The four rotating bodies 44 protrude from the front surface of the protruding portion 44E. When the mandrel 45 passes through the perforations 41b to the through holes 44a, the first rotating body 41 to the fourth rotating body 44 are prevented from being misaligned.

  As shown in FIG. 1, the anvil 50 includes a truncated conical connection portion 51 having a front portion as a head, and a front end portion 53 connected to the front end of the connection portion 51. On the rear surface of the connecting portion 51, a pair of convex portions 52 and 52 that protrude toward the fourth rotating body 44 are provided. The pair of convex portions 52, 52 are arranged at positions shifted by 180 ° around the axis of the anvil 50 and are configured to be able to abut on the front inner peripheral convex portion and the front outer peripheral convex portion (not shown) of the fourth rotating body 44. Has been. The fourth rotating body 44 can rotate 120 ° with respect to the anvil 50 by the configuration of the convex portions 52, 52, the front inner peripheral convex portion and the front outer peripheral convex portion (not shown). Therefore, the weight 40 is apparently rotatable by 120 ° with respect to the anvil 50.

  As shown in FIG. 3, a perforation 51 a formed along the axis is formed at the axial center position on the rear surface of the connecting portion 51. The perforation 51a has an inner diameter similar to that of the perforation 41b, and the front end of the mandrel 45 is inserted therein. Since the anvil 50 is supported on the metal bearing 39 (FIG. 1) as described above, the mandrel 45 is also supported on the metal bearing 39 via the anvil 50.

  As shown in FIG. 1, the front end portion 53 is formed integrally with the connection portion 51, has a cylindrical shape in which an opening is formed in the front end surface and the rear side is closed, and is rotatably supported by the metal bearing 39. ing. The front end portion 53 is exposed from the front end of the body housing portion 11 to the outside of the body housing portion 11 and protrudes forward from the body housing portion 11.

  The front end portion 53 is provided with a cylindrical sleeve 54 so as to surround the front end portion 53. A convex portion 54A that protrudes inward in the radial direction of the sleeve 54 is provided on the inner peripheral surface of the sleeve 54, and the sleeve 54 is movable in a predetermined range in the front-rear direction. Further, the cylindrical inner space of the front end portion 53 forms a tip tool engagement recess 53b that can engage a rear end portion of a tip tool (not shown) such as a hexagon socket.

  The front end portion 53 is formed with a plurality of ball holding holes 53c that allow the external space and the internal space of the front end portion 53 to communicate with each other. One ball 55 is disposed in each of the plurality of ball holding holes 53c. The ball 55 can move outward in the radial direction of the front end portion 53 when the sleeve 54 is not in contact with the convex portion 54A of the sleeve 54 due to the movement of the sleeve 54 in the front-rear direction. At this time, the rear end portion of the tip tool (not shown) is inserted into the tip tool engagement recess portion 53b, and the ball 55 is engaged with the recess portion (not shown) formed in the rear end portion. Thereafter, the sleeve 54 is moved to bring the ball 55 into contact with the convex portion 54A of the sleeve 54, whereby the ball 55 is restricted from moving outward in the radial direction of the front end portion 53, and a tip tool (not shown) is shown. Is connected to the front end portion 53 so as not to be detached from the front end portion 53.

  The tip tool (not shown) has a hexagonal recess formed in the tip of the same shape as the head of the bolt. The tip of the tool is driven by driving the motor 30 with the screw head engaged in the recess. Bolts and the like can be tightened by rotating the tool. The front end portion 53 corresponds to a tip tool holding portion.

As described above, the weight 40 is divided into the four first rotating bodies 41 to the fourth rotating body 44, and the masses of the first rotating body 41 to the fourth rotating body 44 are expressed as m1 to m4 (m1). + m2 + m3 + m4 = the M) and by defining the rotational energy formic of the weight 40 is provided generally at 1 / 2Iω ^ 2. Here, I is the moment of inertia, and ω is the angular velocity (rad / s). The moment of inertia I is given by 1/2 Mr ^ 2, where r is the radius of the first rotating body 41 to the fourth rotating body 44. Since m1 to m4 and r are constants, the rotational energy depends on the angular velocity: ω.

  The rotation angle of the fourth rotating body 44 that is in contact with the anvil 50 is rotatable with respect to the anvil 50 is 120 ° that is less than 360 °. However, as described above, until the rotational force is transmitted from the weight 40 to the anvil 50, that is, the fourth rotating body 44 rotates to the front inner peripheral convex portion and the front outer peripheral convex portion (not shown). Since the first rotating body 41 to the third rotating body 43 can rotate before coming into contact with the portions 52, 52, the motor 30 is driven from the state where the weight 40 is stopped, and the fourth rotating body 44 rotates. In this state, rotational energy can be transmitted from the third rotating body 43 to the fourth rotating body 44 in a state where the rotating energy is gradually accumulated and the rotational energy is sufficiently accumulated until it contacts the anvil 50. it can. Thereby, the 4th rotary body 44 can be made to contact | abut to the anvil 50 in the state which raised angular velocity. In addition, when the 4th rotary body 44 contact | abuts to the anvil 50, since each convex part of the adjacent 1st rotary body 41-the 4th rotary body 44 is contacting, it is the 1st rotary body 41- 4th. The rotating body 44 is integrated, so that the rotational energy accumulated in the first rotating body 41 to the fourth rotating body 44 is transmitted to the anvil 50. Therefore, the 1st rotary body 41-the 4th rotary body 44 will contact | abut to the anvil 50 by the angular velocity increased as a whole, and the striking force which generate | occur | produces in the anvil 50 can be raised.

  Assuming that the weight 40 does not form the above-described divided structure, the weight 40 comes into contact with the anvil 50 only by rotating 120 ° from the stopped state. In this case, the weight 40 is rotated integrally by the motor 30, but the angular velocity of the weight 40 cannot be increased sufficiently in a state where the weight 40 is rotated by 120 ° from the stop state due to the inertia force of the weight 40. In contrast, in the structure in which the weight 40 according to the first embodiment is divided, the weight 40 apparently rotates only 120 ° with respect to the anvil 50, but the first rotating body 41 to the third rotating body. 43 is rotating with respect to the fourth rotating body 44, the first rotating body 41, which is actually at least part of the weight 40, rotates more than one turn with respect to the anvil 50, and the weight 40 makes one turn with respect to the anvil 50. Compared to a weight that has been rotated as described above and has the same weight and outer diameter but is not divided, the angular velocity when contacting the anvil 50, that is, the rotational energy transmitted to the anvil 50 as a striking force is increased. Can do.

  The control by the control device 15 and the operation of the tightening tool 1 when the screw is tightened by the tightening tool 1 are as shown in the flowchart in FIG. 8 and the time chart in FIG. First, the rotational speed of the motor 30 and the upper limit value of the current flowing through the motor 30 are input and set from an operation unit (not shown) (S1). Next, the operator operates the trigger 13 to start driving the motor 30 (S2). When the driving of the motor is started, the rotational energy is accumulated in advance in the weight 40 in a state where the rotational energy can be accumulated (S3, section F in FIG. 9).

  The first rotating body 41 to the third rotating body 43 are in contact with adjacent rotating bodies, and the fourth rotating body 44 is in contact with the anvil 50, so that the motor 30 and the anvil 50 rotate integrally, and the anvil 50 The held screw also rotates. At this time, in a state where there is almost no resistance to screw tightening, that is, in a free-run state, the screw rotates and the rotational speed increases (S4). Thereafter, when the number of revolutions of the motor 30 set in S1 is reached, the motor 30 continues to rotate at a constant number of revolutions until the screw is seated as described later (S5, section H in FIG. 9).

  Next, when the screw is seated and the rotation of the screw stops (S6, point B in FIG. 9), the current value detected by the current detector (not shown) increases rapidly, the torque increases rapidly, and the rotation The speed decreases rapidly (S7, section C in FIG. 9). When the current value becomes larger than the upper limit value of the current stored in the storage device (not shown) (S7, point D in FIG. 9), the supply of current to the motor 30 is stopped or the electronic The clutch is performed (S8). Here, the electronic clutch means that a low current is supplied to the motor 30 under the control of the control device 15 to cause the motor 30 to perform forward and reverse operations in small increments.

  In the present embodiment, since the weight 40 having a large moment of inertia is rotated at a high speed, it is difficult to control the tightening torque. In addition, when a screw generates resistance before it is seated due to a dimensional error between the screw and the hole or when foreign matter is caught between the screw and the hole during screw tightening, the required rotational speed cannot be obtained and the screw The tightening performance is expected to decrease. Further, the rotational energy at the time of sitting also decreases when the rigidity of the tightened object to which the screw or the like is tightened is low.

  However, since the control is performed by the control device 15 as shown in the above flowchart, a slight difference in resistance at the time of screw tightening can be adjusted. Further, if the current supplied to the motor 30 at the time of sitting exceeds the upper limit value, the excess rotational energy can be cut off by interrupting or reducing the supply of electric power (electronic clutch).

  Since the weight 40 is connected to the rotating shaft portion 31 of the motor 30 and can rotate integrally with the rotating shaft portion 31, the screw to be tightened by the rotation of the tip tool can be rotated in the direction of rotation only once when the seat is finally tightened. You can make a blow to.

  For this reason, since an impact does not arise inside the tightening tool 1, the impact sound is small, and the reaction transmitted to the hand can be suppressed. Further, the torque can be controlled by adjusting the rotational speed by electrical control. Moreover, since the rotation speed reduction mechanism is not provided between the rotating shaft part 31 of the motor 30, the reaction transmitted to a hand can be suppressed as much as possible.

  The flowchart shown in FIG. 8 shows a process of tightening in a normal operation that does not require excessive torque when the motor 30 is started. On the other hand, in the retightening performed after the screw is tightened or the operation of loosening the tightened screw, an excessive torque is required when the motor 30 is started. In this case, the rotational energy needs to be accumulated in the weight 40 in advance. Specifically, when a motor reversing switch (not shown) is pressed, the motor 30 is rotated at a predetermined angle in a direction (reverse direction) opposite to the current rotation direction (forward rotation direction) defined by the changeover switch (not shown). Rotate (motor rotating means). Here, the “predetermined angle” means that the first rotating body 41 can be rotated in the 240 ° forward rotation direction with respect to the second rotating body 42 so that the weight 40 can accumulate the maximum rotational energy, and the second rotation. The body 42 can be rotated in the 240 ° forward rotation direction with respect to the third rotating body 43, the third rotating body 43 can be rotated in the 240 ° forward rotation direction with respect to the fourth rotating body 44, and the fourth rotating body. This is an angle (240 ° × 3 + 120 ° = 840 °) that enables 44 to rotate in the 120 ° forward rotation direction with respect to the anvil 50.

  By pulling the trigger 13 from this state and rotating the motor 30 in the forward rotation direction, a large striking force can be applied to the anvil 50, and the work of retightening and loosening the tightened screw can be suitably performed. Further, the impact sound generated at this time is abutted between the first rotating body 41 and the second rotating body 42, abutted between the second rotating body 42 and the third rotating body 43, and the third rotating body 43 and the fourth rotating body. The contact occurs with the contact of the body 44 and the contact of the fourth rotating body 44 and the anvil 50 in total, but this contact is performed in a very short time. Is recognized as a single hitting sound, and noise can be reduced.

  The control for rotating the motor 30 by the predetermined angle is not limited to pressing a motor reversing switch (not shown). For example, in the flowchart shown in FIG. 8, the motor 30 is reversed by a predetermined angle between S1 and S2. A flow may be inserted (reversing means during motor rotation). According to such control, the weight 40 can always be in a state where rotational energy can be accumulated at the maximum at the start of work. In the flowchart in FIG. 8, a flow for reversing the motor 30 by a predetermined angle may be further inserted after S8 (reversing means when the motor is stopped). According to such control, when the next operation is performed after the motor 30 is stopped, the weight 40 can be in a state where the rotational energy can be accumulated to the maximum.

  The tightening tool 1 includes a switch (not shown) that switches the rotation direction of the motor 30 (the rotation direction of the tip tool (not shown)). For example, when the forward rotation direction of the motor 30 is clockwise, the weight 40 When the motor 30 is rotated in the counterclockwise direction by a changeover switch (not shown) after being inverted by a predetermined angle so that the rotational energy can be accumulated, the rotational energy is accumulated even if the weight 40 is driven. I can't do it. Therefore, when there is a signal input from a changeover switch (not shown) in the control device 15, the motor 30 is moved at a predetermined angle in the opposite direction to the normal rotation direction in which the motor 30 rotates based on the input signal from the changeover switch. Is rotated (motor reversing means). According to such control, when the number of rotations of the motor 30 is switched and the motor 30 is rotated forward, the weight 40 can be in a state in which rotational energy can be accumulated to the maximum.

  Next, a second embodiment of the present invention will be described with reference to FIG. The tightening tool 101 shown in FIG. 10 has a configuration in which the shapes of the weight 40 and the anvil 50 of the tightening tool 1 according to the first embodiment are mainly different. Therefore, except for a different configuration, 100 is added to the reference numeral of the tightening tool 1 and its description is omitted.

  The weight 140 is configured in a single columnar shape, and is disposed in a space formed by the inner cover 136 and the hammer case 138 with the axial direction of the column being the front-rear direction. A columnar rear end protruding portion 141 protruding from the rear surface of the weight 140 is provided on the axial center and rear surface of the weight 140, and the weight 140 rotates to the metal bearing 37 on the outer periphery of the rear end protruding portion 141. It is supported as possible. In addition, an engaging recess 141a with which the weight engaging portion 134 is engaged is formed on the axial center of the rear end protruding portion 141 and at the rear end position.

  A columnar front end protruding portion 142 that protrudes from the front surface of the weight 140 toward the anvil 150 side is provided on the axial center and on the front surface of the weight 140. The front end protruding portion 142 has a perforation 151a described later. It is inserted in and is rotatably supported. A series of grooves 142 a are formed at the base position of the front end side protruding portion 142 on the front surface of the weight 140 so as to surround the outer periphery of the front end side protruding portion 142. A pair of convex portions 143 and 143 projecting toward the anvil 150 are provided at the outer peripheral position on the front surface of the weight 140. The pair of convex portions 143 and 143 are arranged at positions shifted by 180 ° around the axis, and have a symmetrical shape around the axis.

  The front end side projecting portion 142 is provided with a spring 144 that is inserted into the groove 142a and urges the anvil 150 in contact therewith.

  The anvil 50 includes a truncated conical connecting portion 151 having a front portion as a head, and a front end portion 153 connected to the front end of the connecting portion 151, and is rotatable with respect to the hammer case 138 and slidable back and forth. It is configured to be movable. A pair of convex portions 152, 152 projecting toward the weight 140 is provided on the rear surface of the connecting portion 151. The pair of convex portions 152, 152 are arranged at positions shifted by 180 ° around the axis of the anvil 150, and the pair of convex portions 143, 143 of the weight 140 with the anvil 150 moving forward most The abutment 150 is configured to be in contact with the pair of convex portions 143 and 143 in the circumferential direction in a state where the anvil 150 has moved rearward.

  In addition, a perforation 151a is formed at the axial center position on the rear surface of the connecting portion 151 along the axial center. The perforation 151a is formed so that the inner diameter thereof is slightly larger than the outer diameter of the front end side protruding portion 142, the front end of the front end side protruding portion 142 is inserted therein, and the front end side protruding portion 142 is perforated. The anvil 150 has a drilling depth that allows the anvil 150 to move back and forth with respect to the weight 140 in a state of being inserted into the 151a. Since the anvil 150 is supported by the metal bearing 139 as described above, the front end side protrusion 142 is also supported by the metal bearing 139 via the anvil 150.

  As described above, since the spring 144 is mounted on the front end side protruding portion 142, the spring 144 is interposed between the weight 140 and the anvil 150 by inserting the front end side protruding portion 142 into the perforation 151a. The anvil 150 is urged forward by the spring 144 against the weight 140. With this configuration, unless the anvil 150 moves backward against the urging force of the spring 143, no rotational force is transmitted from the weight 140 to the anvil 150.

  The front end portion 153 is formed integrally with the connection portion 151, has a cylindrical shape with an opening formed on the front end surface and closed on the rear side, and is supported by the metal bearing 139 so as to be rotatable and slidable back and forth.

  When working with the tightening tool 101 having the above-described configuration, the trigger 113 is pulled after the tightening tool 101 is pressed to the screw side, that is, the front side in a state where the screw is engaged with a tip tool (not shown), The motor 130 is rotated. By pressing the tightening tool 101 toward the front side, the anvil 150 moves relative to the weight 140, that is, toward the weight 140 side, and the pair of convex portions 143 and 143 and the pair of convex portions 152 and 152 are moved. It becomes possible to contact in the circumferential direction. When the motor 130 rotates in this state, the weight 140 also rotates. When the pair of convex portions 143 and 143 and the pair of convex portions 152 and 152 come into contact with each other, the rotational force is applied to the anvil 150 and a tip tool (not shown). It is transmitted and it becomes possible to tighten the screw.

  Further, in the retightening performed after the screw is tightened or the operation of loosening the tightened screw, the trigger 113 is pulled before the tightening tool 101 is pushed forward with the screw engaged with the tip tool, and the weight 140 is pulled. Is idled without contacting the anvil 150. The weight 140 and the anvil 150 are connected to each other by pressing the tightening tool 101 in a state where the rotational energy is accumulated in the weight 140, that is, in a state where the angular velocity is the highest, and the rotational energy of the weight 140 is connected to the anvil. Converted to 150 striking power.

  With such a configuration, the rotational energy stored in the weight 140 can be set to the highest energy state, and the rotational energy can be converted into the striking force of the anvil 150 in the high energy state. Further, since the contact between the pair of protrusions 143 and 143 and the pair of protrusions 152 and 152 is only once, the hitting sound can be reduced.

  In the first embodiment and the second embodiment, the front end portion and the tip tool are separate bodies, but they may be configured integrally. In the first embodiment, the rotational energy is accumulated by dividing the weight, and in the second embodiment, the rotational energy is accumulated by making the weight and the anvil into a disconnected state and a connected state. Although described as separate embodiments, these may be combined. Specifically, the shape of the anvil is the second embodiment, the shape of the weight is the first embodiment, and the front shape of the fourth rotating body is the front shape of the weight of the second embodiment. As a result, rotational energy can be accumulated by the weight, and the weight and the anvil can be in a disconnected state and a connected state.

  In the present embodiment, the weight is directly fixed to the rotation shaft of the motor, so that it can rotate integrally with the rotation shaft portion of the motor. However, the weight may not be fixed directly.

  In the first and second embodiments, the number of rotations of the motor is controlled, and the current value supplied to the motor is changed depending on the magnitude of the current value flowing through the motor. However, the present invention is not limited to this, and only one of them may be controlled.

  In the first and second embodiments, the brushless motor that is an electric motor is used. However, the present invention is not limited to the brushless motor. For example, an air motor or the like may be used.

In the first and second embodiments, the “screw” to be tightened with the tightening tool is specifically a bolt and a nut, but is not limited thereto. Any load may be used as long as the load for rotating is hardly applied at the start of tightening and the load is rapidly increased when the tightening is completed.
In the first embodiment, the rotating body adjacent to one rotating body is configured to rotate by 240 ° as an angle near 360 ° and less than 360 °. However, the present invention is not limited to this angle. Various angles can be set as long as the angle is less than 360 ° in accordance with various properties such as the material, number of sheets, and size of the rotating body.

  The fastening tool of the present invention is particularly useful in the field of fastening tools for fastening screws and the like.

1: Tightening tool 10: Housing 11: Body housing part
12: Handle housing part 13: Trigger 14: Battery 15: Control device 30: Motor 31: Rotating shaft part 32: Bearing 33: Fan 34: Engaging part 34A: Side 34B: Arc 36: Inner cover 37: Metal bearing 38: Hammer case 39: Metal bearing 41: First rotating body 41C: Front inner peripheral convex portion 41D: Front outer peripheral convex portion 41E: Protruding portion 41a: Engaging concave portion 41b: Perforation 42: Second rotating body 42A: Rear inner peripheral surface Side convex portion 42B: Rear outer peripheral convex portion 42C: Front inner peripheral convex portion 42D: Front outer peripheral convex portion 42E: Protruding portion 42a: Through hole 43: Third rotating body 43A: Rear inner peripheral convex portion 43B: Rear surface Outer peripheral convex portion 43C: Front inner peripheral convex portion 43D: Front outer peripheral convex portion 43E: Protruding portion 43a: Through hole 44: Fourth rotating body 44A: Rear inner peripheral convex portion 44B: Rear outer peripheral convex portion 44E: protrusion 44a: through hole 45: mandrel
50: Anvil 51: Connection part 51a: Perforation 52: Protruding part 53: Front end part 53b: Tip tool engaging concave part 53c: Ball holding hole 54: Sleeve 54A: Convex part
55: Ball 101: Tightening tool 113: Trigger 130: Motor 134: Engaging portion 136: Inner cover 138: Hammer case 139: Metal bearing 141: Rear end side protruding portion 141a: Engaging recess 142: Front end side protruding portion 142a :groove
143: Convex 144: Spring 150: Anvil 151: Connection 151a: Perforation 152: Convex 153: Front end

Claims (8)

A motor,
A weight that is rotated by the motor and can accumulate rotational energy;
An output shaft portion that is connectable to the weight and has a tip tool holding portion on which a tip tool is mounted;
The weight is composed of a plurality of rotating bodies that are arranged in the axial direction of the weight and are rotatable about the axis as a rotation axis.
The plurality of rotating bodies can be connected to the output shaft portion of the rotating body located on one end side in the axial direction, and the rotating body located on the other end side is rotationally driven by the motor to rotate each of the rotating bodies. The body abuts against the adjacent rotating body when the rotating body adjacent to each rotating body rotates less than 360 ° with respect to each rotating body regardless of the pressing of the tip tool. A tightening tool comprising: The motor is directly connected to the rotating body located on the other end side, and the weight and the output shaft portion are connected to the output shaft portion in a state in which the weight rotates one or more times around the shaft of the weight. 2. The tightening tool according to claim 1, wherein the tightening tool is configured to be able to transmit rotational energy, and the output shaft portion is configured to be directly connectable to the weight after the weight has rotated one or more rounds. A controller for detecting the current flowing to the motor and controlling the rotation of the motor;
The control device includes a rotation speed control means for controlling the rotation speed of the motor to a constant rotation speed after the motor starts, and a motor stop for stopping the rotation of the motor when a current flowing through the motor reaches a specified value. The fastening tool according to claim 1, comprising at least one or both of the means. 4. The weight and the output shaft portion are configured so that rotational energy can be transmitted to the output shaft portion in a state in which the weight rotates at least once around the axis of the weight. The tightening tool according to any one of the above . A controller for controlling the rotation of the motor; and a switch for outputting a signal to the controller,
When the motor is stopped, the control device allows the rotating body located on the other end side in the axial direction to be rotated around the axis within a range of less than 360 ° with respect to the adjacent rotating body. The tightening tool according to claim 1, further comprising motor rotation means for rotating the motor so as to rotate in a direction opposite to the rolling direction . A control device for controlling the rotation of the motor;
When the motor is started from a stopped state and the weight is rotated to one side around the axis, the rotating body positioned on the other end side in the axial direction is at least less than 360 ° with respect to the adjacent rotating body. Motor rotation reversing means for rotating the motor so as to rotate the weight to the one side after rotating the motor to rotate to the other side around the axis in a range;
When the motor is stopped from the rotational state in which the weight is rotated to the one side, the rotating body positioned on the other axial end side is at least less than 360 ° with respect to the adjacent rotating body on the other side around the axis. 2. The fastening tool according to claim 1, further comprising at least one means of a motor stop reversing means for stopping the motor after rotating the motor so as to rotate in the direction. A control device for controlling the rotation of the motor; and a changeover switch for outputting a signal for switching forward / reverse rotation of the motor to the control device,
When the switching signal is input from the changeover switch, the control device is configured to apply the rotation of the rotary body located at one end in the axial direction to the adjacent rotary body based on the signal input from the changeover switch. The tightening tool according to claim 1, further comprising a motor switching reversing means for rotating the motor so that the motor rotates in a direction opposite to the direction in which the motor rotates in a range of at least less than 360 °. A holding portion that holds the output shaft portion around a rotation axis of the output shaft portion and is slidable in a direction parallel to the rotation shaft;
The output shaft portion and the weight are arranged coaxially, and include a contact portion that can contact each other only when the output shaft portion slides on the weight side. The fastening tool according to any one of claims 1 to 3.

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