JP2019034368A - Reaction force alleviation device of nut runner - Google Patents

Abstract

To provide a portable nut runner which comprises a device for reducing and alleviating a reaction force generated when loosening of a screw, reduces a physical load on an operator which occurs when fastening the screw by a nut runner alone, and can perform safely and easily fastening/loosening work.SOLUTION: A rotor output system of a motor which is driven by power, and a stator stationery side of the motor for rotating the rotor are connected to each other by a cam. An output shaft 4, to which a tool So for fastening/loosening work, which is rotatably supported on a body case C1, C2 by a bearing, is mounted, the stator stationery side of the motor fixed to the body case C1, C2, and a cam outer ring 7 are integrally connected by a connection cam 6, and rotation of the output shaft 4 is stopped, thereby reducing and alleviating a reaction force generated when loosing a screw. Further, rotation driven by power of the output shaft 4 is permitted by making non-connection, thereby fastening the screw.SELECTED DRAWING: Figure 7

Description

The present invention relates to a reaction force relaxation of a screw tightening / loosening tool, and more particularly to a reaction force relaxation device for a nut runner that reduces and reduces a reaction force generated when a screw is tightened.

Conventionally, a nut runner that uses a motor as a screw tightening / loosening tool to increase the output by a speed reducer and perform a screw tightening / loosening operation has been put to practical use. The motor stator side is fixed to the main body case, the motor rotor side is connected to an output shaft that performs a loosening operation via a speed reducer, and is rotatably supported on the main body case by a bearing. Such a nut runner can grip and tighten the main body case and drive and rotate the output shaft.

However, this type of nut runner, especially in screw tightening work, when the screw head is seated, the screw head is seated, and even if the output shaft stops rotating, the driving force is transmitted to the output shaft, and the motor side stator side The rotor side and the rotor side repel each other by interaction, and a reaction force acts on the gripping portion of the main body case on the reverse rotation side in the tightening direction.

Therefore, a reaction force receiver, which is a protrusion for reaction force prevention, is provided near the tip of the nut runner body in the direction orthogonal to the output shaft, and a reaction force acting on the nut runner by contacting an external object is transmitted to the body. The reaction force acting on the case gripping part is reduced and relaxed to prevent reverse rotation of the nut runner.

Japanese Patent No. 2768636 Japanese Patent Laid-Open No. 05-042487 Japanese Patent No. 5635897

The nut runner provided with the reaction force receiver, which is a protrusion for preventing reaction force in Patent Document 1, requires an external object that can contact the reaction force receiver in the vicinity of the tightening location. In a work environment where contact is impossible or there is no external object that can accept reaction force, reaction force reception does not function. Moreover, when the reaction force washer of Patent Document 3 is used, the outer socket diameter for the reaction force washer is large, and when the screw head is submerged, there is a concern that the counterbore diameter will increase.

Therefore, the present invention eliminates the reaction force receiver, which is a protrusion for preventing reaction force, on the outside of the tool and installs a device in the tool to relieve the reaction force generated when the screw is tightened. It is an object of the present invention to provide a nut runner that can be easily tightened and loosened even in a working environment where contact cannot be made or there is no other external object that can accept a reaction force.

In order to solve the above-mentioned problems, a nut runner reaction force reducing device according to the invention of claim 1 is formed with a connecting cam, a power transmission receiving surface, and a plane engaging with the connecting cam, and a tightening work tool. An output shaft on which the steel ball is attached and detached, a steel ball that forms cam grooves and transmits power, a drive shaft to which the power is mounted, power is transmitted to the drive shaft by the steel ball, and circumferential swinging A clutch that is loosely fitted so as to be capable of sliding in the axial direction within a certain range at the same time, and has a power transmission surface and a positioning shaft on its end surface, and holding the connecting cam by the positioning shaft, the power transmission surface, and the power The transmission receiving surface and the connecting cam are housed in an inner peripheral surface, and the output shaft is rotatably supported and is configured by a cam outer ring fixed to the main body case, the output shaft, the connecting cam, and the The cam outer ring is connected or disconnected.

According to a second aspect of the present invention, in the motor, the output is formed by directly coupling and fitting with an output portion of a driven reduction gear to form the flat surface that engages with the connecting cam, and the tightening work tool is attached and detached. A shaft that is loosely fitted so as to be non-rotatable and slidable in the axial direction with respect to the output shaft, the clutch having the positioning shaft, and the outer periphery of the small diameter portion of the clutch on the outer periphery of the small-diameter portion An electromagnet that is loosely fitted so that the clutch is rotatable in the circumferential direction and slidable in the axial direction, and the coupling cam is accommodated in the inner circumferential surface, and the output shaft is rotatably supported and fixed to the body case. The cam outer ring is configured to connect or disconnect the output shaft, the connecting cam, and the cam outer ring.

According to a third aspect of the present invention, the flat surface that engages with the connecting cam is formed, the output shaft to which the tightening / loosening tool is attached and detached, and non-rotatable with respect to the output shaft and slidable in the axial direction The clutch having the positioning shaft and holding the connecting cam and the connecting cam accommodated in the inner peripheral surface and rotatably supporting the output shaft are fixed to the main body case. The cam outer ring, and the output shaft, the connecting cam, and the cam outer ring are connected or disconnected, and the positioning shaft of the connecting cam is slid only in the axial direction. A mechanism for moving the positioning shaft to a fixed holding position of the connecting cam and a fixed holding releasing position; and when the connecting cam is in the fixed holding releasing position, Screws can be tightened by hand And features.

In such a configuration, it is possible to obtain a high torque from a small motor by increasing the reduction ratio, and by eliminating the striking mechanism, the reaction force generated at the time of screw tightening is reduced and relaxed with low noise and low vibration, Simple and safe tightening work can be performed. Further, it has the same configuration as the drill for drilling work, and the reaction force generated by the biting of the drill tool tip at the end of drilling into the work material is reduced and reduced. Therefore, there is no distinction between a screw tightening tool and a drilling tool.

It is a whole side view of nut runner 100 concerning a 1st embodiment. FIG. 3 is a side cross-sectional view of the nut runner 100 (a cylindrical connecting cam 6a and a flat surface 43a corresponding to the cylindrical connecting cam) according to the first embodiment when the reaction force relaxation device is not in operation. It is a reaction force relaxation apparatus of the nut runner 100 (gear type connection cam 6b and the plane 43b corresponding to the gear type connection cam) according to the first embodiment, and is a side cross-sectional view during operation. (A) It is an assembly drawing of the reaction force mitigation device of the nut runner 100 (the columnar connecting cam 6a and the plane 43a corresponding to the columnar connecting cam) according to the first embodiment. (B) It is an assembly drawing of the reaction force relaxation apparatus of the nut runner 100 (The gear type connection cam 6b and the plane 43b corresponding to the gear type connection cam) according to the first embodiment. (A) It is sectional drawing at the time of non-operation of the reaction force relaxation apparatus seen from the motor side of the nut runner 100 (Cylinder type connection cam 6a and the plane 43a corresponding to a column type connection cam) which concerns on 1st Embodiment. (B) It is the reaction force relaxation apparatus seen from the motor side of the nut runner 100 (Cylinder type connecting cam 6a and the cylinder type connecting cam corresponding plane 43a) concerning 1st Embodiment, It is sectional drawing at the time of an action | operation. (C) Reaction force mitigation device viewed from the motor side of the nut runner 100 (gear-type coupling cam 6b and the plane 43b corresponding to the gear-type coupling cam) according to the first embodiment. (B) It is reaction force mitigation device seen from the motor side of nut runner 100 (gear type connecting cam 6b and gear type connecting cam corresponding plane 43b) concerning a 1st embodiment, and a sectional view at the time of operation. It is an exploded parts figure of nut runner 100 concerning a 1st embodiment. It is a partial cross section assembly drawing of the nut runner 200 which concerns on 2nd Embodiment. It is an exploded parts figure of nut runner 200 concerning a 2nd embodiment. (A) It is sectional drawing at the time of non-operation of the reaction force relaxation apparatus seen from the motor side of the nut runner 200 (Cylinder type connection cam 6a and the plane 43a corresponding to a column type connection cam) concerning 2nd Embodiment. (B) Reaction force mitigation device viewed from the motor side of the nut runner 200 (gear-type coupling cam 6b and the plane 43b corresponding to the gear-type coupling cam) according to the second embodiment, a sectional view during operation. It is a partial cross section assembly drawing of the nut runner 300 concerning a 3rd embodiment. It is a partially exploded parts figure and cross-section assembly drawing of the nut runner 300 concerning a 3rd embodiment. (A) It is the tightening state figure (nut runner 100) which turned the screw clamp machine main body concerning 3rd Embodiment by hand. (B) It is the clamp | tightening state figure (nut runner 200) which rotated the screw clamp machine main body which concerns on 3rd Embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a reaction force mitigation device for a nut runner of the present invention will be described based on the drawings. The same reference numerals are used for the same and similar components in the accompanying drawings, and the description may be omitted. The plane of the connecting cam and the output shaft is a combination of the columnar connecting cam 6a and the plane 43a corresponding to the columnar connecting cam, or a rack in which the plane engaging with the geared connecting cam 6b and the connecting cam is a linear gear. Some of the formed combinations of the planes 43b corresponding to the gear-type coupling cams can be adopted. However, in this description, the coupling cam 6 and the plane 43 may be used. The power source can be used as appropriate, such as an electric motor or an air motor. In this description, an electric motor is used, and various types of speed reducers can be used as appropriate, but in this description, the planetary gear mechanism is used as an example for rotation. The direction is viewed from the motor side, and the right screw is used. In the tightening operation, the body case C1 is gripped, the switch Sw is operated, and the motor M is rotationally driven by the power of the storage battery Ba. Here, the main body case C1 is divided into two substantially symmetrically, and a main body case C2 is attached.

[Structure of the nut runner 100 according to the first embodiment]
1, 2, 4 (a), 5 (a), 5 (b), and 6, the columnar connecting cam 6 a of the nut runner 100 according to the first embodiment and the plane 43 a corresponding to the columnar connecting cam are shown. FIG. 3, FIG. 4 (b), FIG. 5 (c), (d), and FIG. 6 show the gear-type connecting cam 6b and the plane 43b corresponding to the gear-type connecting cam.

The connecting cam 6, the flat surface 43 that engages with the connecting cam 6, and the power transmission receiving surface 42 are formed, and the output shaft 4 from which the tightening / loosening work tool So is attached and detached, and the cam groove 15 are formed to drive the power. A drive shaft 1 on which a steel ball 2 to be transmitted is mounted, power is transmitted to the drive shaft 1 by the steel ball 2, and circumferential swing and axial slide are simultaneously possible within a certain range. The clutch 3 fitted with the power transmission surface 35 and the positioning shaft 5 in the large-diameter portion 32 and holding the coupling cam 6 by the positioning shaft 5, the power transmission surface 35, the power transmission receiving surface 42, and the coupling cam 6 The cam outer ring 7 is housed in the peripheral surface 71, is rotatably supported by the output shaft 4 and is fixed to the main body case C2.

The drive shaft 1 is a carrier that supports the shaft of a planetary gear, which is an output portion of a reduction gear whose large diameter portion 12 is driven by a motor, by a hole 13, and is supported by a bearing Br2 so that the clutch 3 is moved in the circumferential direction. In order to enable swinging and sliding in the axial direction simultaneously within a certain range, the shaft portion 11 has a sharp portion on the output shaft 4 side and a V-shaped hemispherical cam groove 15 is formed to transmit power. The steel ball 2 to be rolled is mounted so as to be able to roll, and the small-diameter portion 16 is loosely fitted into the hole 45 in the end face of the output shaft 4 and is supported.

The clutch 3 engages with the steel ball 2 to enable circumferential swing and axial slide simultaneously within a certain range, and a cam groove 34 for transmitting power is formed to drive the drive shaft 1. Of the small diameter portion 33 of the clutch 3 between the end surface of the large diameter portion 12 of the drive shaft 1 and the end surface of the large diameter portion 32 of the clutch 3. The coil spring CS is arranged with the guide as shown in FIG. 5 and is urged toward the output shaft 4 side and locked by the steel ball 2. The positioning shaft 5 is provided in the hole 36 formed in the large diameter portion 32 to hold the connecting cam 6. The power transmission surface 35 is slidably engaged with the power transmission receiving surface 42 of the output shaft 4 while being engaged with the flat surface 43 of the output shaft 4.

The front end shaft portion 51 on the projecting side of the positioning shaft 5 is formed on a conical tip, and the positioning hole 61 on one end of the connecting cam 6 is also formed on the conical tip. The end surface of the positioning shaft may be a positioning hole and the end surface of the connecting cam may be a conical tip shaft.

The cam outer ring 7 has an inner peripheral surface 71 and an inner peripheral surface end 71a, a bearing hole 72, and a cam for receiving the connecting cam 6, the power transmission surface 35 of the clutch 3, and the power transmission receiving surface 42 of the output shaft 4. The outer ring 7 includes a rotation stopper 73 that fixes the outer ring 7 to the main body case C2 in a non-rotatable manner.

The output shaft 4 is formed by a rear shaft portion 41b, an end surface hole 45, a power transmission receiving surface 42, a flat surface 43, a retaining ring groove 44, a front shaft portion 41a, and a tightening work tool engaging portion 46. 41a is supported by a bearing Br1 mounted on the cam outer ring 7, and a tightening work tool So is provided by projecting a tightening work tool engaging portion 46 from the main body case C2.

[Operation of the first embodiment nut runner 100]
The tightening operation is performed by holding the main body case C1 and operating the switch Sw to rotate the motor M with the power of the storage battery Ba. When the nut runner is stopped, the drive shaft 1 is connected to the shaft portion 11 and the clutch 3. The through hole 31 is loosely fitted, and the clutch 3 is urged toward the steel ball 2 by the coil spring CS, and power is transmitted by the cam groove 15 of the drive shaft 1, the cam groove 34 of the clutch 3, and the steel ball 2. And the axial direction of the clutch 3, the tip shaft portion 51 formed on the conical tip of the positioning shaft 5 attached to the clutch 3, and the conical tip of the tip. The positioning holes 61 of the connecting cam 6 are fitted to each other and brought into contact with the conical tip, so that the connecting cam 6 is accurately positioned and held, and the connecting cam 6 is engaged with the flat surface 43 of the output shaft 4. In addition, the power transmission surface 35 of the clutch 3 is connected to the power transmission of the output shaft 4. As shown in FIGS. 1, 2, 4A and 4B, the drive shaft 1 (not shown in FIG. 4) and the coil spring CS (not shown in FIG. 4) are arranged. Display), steel ball 2 (not shown in FIG. 4), clutch 3, output shaft 4, and connecting cam 6 are integrally connected.

When the nut runner is in no-load operation or when the output shaft 4 has a predetermined load torque or less, the drive shaft 1 provided with the large-diameter portion 12 that is a carrier of the planetary gear includes a coil spring CS, a steel ball 2, a clutch 3, the output shaft 4 and the connecting cam 6 are integrally connected and rotated. As shown in FIGS. 5 (a) and 5 (c), the connecting cam 6 positioned and held by the positioning shaft 5 is connected to the cam. There is a gap V with the inner peripheral surface 71 of the outer ring 7 and is not in contact. Therefore, the output shaft 4, the connecting cam 6, and the cam outer ring 7 are not connected and the reaction force reducing device does not operate and the output shaft 4 rotates. Can continue.

As shown in FIG. 3, when the motor M is rotating and the tightening screw is seated and the output shaft 4 reaches a predetermined torque and stops rotating to generate a reaction force, the drive shaft 1 The steel ball 2 continues to rotate clockwise and rolls and moves to the left cam groove of the V-shaped hemispherical cam groove 15 formed in the shaft portion 11 when viewed from the motor side in FIG. Acts to compress the coil spring CS and slide the clutch 3 and the positioning shaft 5 toward the axial motor M to release the integrated positioning of the positioning shaft 5 and the connecting cam 6. Is in contact with the retaining ring SR and the washer W attached to the output shaft 4 to maintain the axial positioning. The clutch 3 restricts movement by bringing the end face of the small diameter portion 33 of the clutch 3 into contact with the retaining ring SR2 incorporated in the retaining ring groove 14 of the drive shaft 1 to restrict the power transmission between the power transmission surface 35 of the clutch 3 and the output shaft 4. The power transmission is continued without the meshing with the receiving surface 42 being eliminated.

As shown in FIGS. 5 (b) and 5 (d), even if the output shaft 4 stops rotating, power transmission continues to the right rotation, and the main body cases C1 and C2 and the cam outer ring 7 are integrated into the output shaft 4 as a single unit. Rotate the axis of the counterclockwise. The end face of the connecting cam 6 whose positioning has been released is in contact with the inner peripheral surface end 71a of the cam outer ring 7 and is held by the cam outer ring 7 while rotating and rotating around the flat surface 43 of the output shaft 4 to rotate to the left by θ °. It moves and contacts the inner peripheral surface 71 of the cam outer ring 7. In this case, the sum of the distance U from the center of the output shaft 4 to the flat surface 43 and the outer diameter d of the connecting cam 6 is Rb, which is smaller than the radius Ra of the inner peripheral surface 71 of the cam outer ring 7, but the connecting cam 6 and the cam outer ring. 7, the contact portion of the inner peripheral surface 71 is swung outward from the central axis of the cam outer ring 7, becomes smaller than the radius Ra, and the gap V is eliminated. Therefore, the connecting cam 6 is pressed by the wedge action due to the reverse rotation of the output shaft 4 and the cam outer ring 7, and the cam outer ring 7 and the output shaft 4 are integrally connected to suppress or stop the rotation of the motor M. Reducing and mitigating the reaction force that occurs when tightening screws. In this case, the connection cam 6 rotates counterclockwise to push the flat surface 43 of the output shaft 4 to the right side to generate a stress that gives the output shaft 4 a right rotational force, and the reaction force of the cam outer ring 7 is increased by an amount corresponding to the stress. Can be expected to decrease. At the end of the screw tightening / loosening operation, the operation of the nut runner is stopped by detecting changes in the current value acting on the motor M, changes in the rotation speed of the output shaft 4, torque values of the tightened screws, etc. The power can be automatically turned off, or the power can be turned off manually by operating the switch Sw. The detection unit is not shown.

As shown in FIG. 3, the integral positioning of the positioning shaft 5 and the connecting cam 6 is released by the movement of the clutch 3 toward the motor M, but the tip shaft portion 51 of the positioning shaft 5 is positioned in the positioning hole of the connecting cam 6. Since the nut runner stops in 61, the positioning shaft 5 and the connecting cam 6 can be easily positioned when the nut runner is stopped.

[Structure of Nut Runner 200 of Second Embodiment]
The nut runner 200 which concerns on 2nd Embodiment is shown to FIG. 7, FIG. 8, FIG. 9 (a), (b).

An output shaft 4 that is directly connected and fitted to the output drive shaft 1 of the reduction gear that is driven by a motor to form the flat surface 43 that engages with the connecting cam 6 and to which the tightening / loosing tool So is attached and detached, and an output The clutch 3 is loosely fitted so as to be non-rotatable with respect to the shaft 4 and is slidable in the axial direction. The clutch 3 includes the positioning shaft 5 and holds the coupling cam 6. The electromagnet SL, which is rotatable in the circumferential direction and loosely fitted so as to be slidable in the axial direction, and the flat surface 43 of the connecting cam 6 and the output shaft 4 are accommodated in the inner peripheral surface 71 and the inner peripheral surface end portion 71a. 4 is configured by a cam outer ring 7 that is rotatably supported by a bearing Br1 and fixed to the main body case C2.

The connection cam 6 and the plane 43 are either a combination of the columnar connection cam 6a and the plane 43a corresponding to the columnar connection cam or a combination of the gear type connection cam 6b and the plane 43b corresponding to the gear type connection cam. In this description, the connecting cam 6 and the flat surface 43 are used.

The drive shaft 1 is a carrier that supports the shaft of a planetary gear, which is an output portion of a reduction gear whose large diameter portion 12 is driven by a motor, by a hole 13 and is supported by a bearing Br2, and is connected to the connection hole 17 by an output shaft 4 The connecting shaft portion 47 is tightly fitted so as not to rotate. The clutch 3 has a through-hole 31 formed therein, is loosely fitted to the rear shaft portion 41b of the output shaft 4 so as to be slidable in the axial direction and not rotatable in the circumferential direction, and a retaining ring SR2 attached to the output shaft 4 A coil spring CS is arranged between the end faces of the hole 37 of the clutch 3 and is urged toward the bearing Br1. The positioning shaft 5 is provided in the hole 36 provided in the large-diameter portion 32 to hold the connecting cam 6 and output. Engage and place on the flat surface 43 of the shaft 4.

The clutch 3 and the output shaft 4 are slidable in the axial direction and non-rotatable in the circumferential direction in FIG. 7 using a key K and the rotation stoppers 38 and 48 engaged with the key K. The cross section of this portion may be formed in, for example, a polygonal shape such as a hexagon or a spline shown in FIG.

The front end shaft portion 51 on the projecting side of the positioning shaft 5 is formed on a conical tip, and the positioning hole 61 on one end of the connecting cam 6 is also formed on the conical tip.

The cam outer ring 7 includes a connecting cam 6 and an inner peripheral surface 71 that accommodates the flat surface 43 of the output shaft 4 engaged with the connecting cam 6, an inner peripheral surface end 71 a, a bearing hole 72, and the cam outer ring 7. It is comprised with the rotation stop 73 fixed to case C2 so that rotation is impossible.

The output shaft 4 is formed by a connecting shaft portion 47 at the end face, a rear shaft portion 41b, a flat surface 43, a retaining ring groove 44, a rotation stopper 48, a tightening work tool engaging portion 46, and a mounting groove 44 for the retaining ring SR2. The front shaft portion 41a is supported by a bearing Br1 mounted on the cam outer ring 7, and a tightening work tool So is provided by projecting the tightening work tool engaging portion 46 from the main body case C2.

The electromagnet SL is fixed inside the main body cover C2 by fitting the clutch 3 so as to be capable of rotational movement in the circumferential direction and linear movement in the axial direction.

[Operation of Nut Runner 200 of Second Embodiment]
The tightening operation is performed by holding the main body case C1, operating the switch Sw, and rotating the motor M with the power of the storage battery Ba. When the nut runner is stopped, the output directly connected to the output drive shaft 1 is fitted. The shaft 4 is loosely fitted to the output shaft 4 with the rotation stop 48 of the output shaft 4, the rotation stop 38 of the clutch 3, and the key K so as to be non-rotatable and slidable in the axial direction. 5 and the positioning shaft 61 of the connecting cam 6 formed on the cone-shaped tip surface are fitted to each other so that the cone-shaped tip surface is formed. By bringing them into contact with each other, the clutch 3 that is accurately positioned and held by the connecting cam 6 and engaged with the flat surface 43 of the output shaft 4 is brought into contact with the retaining ring SR2 attached to the rear shaft portion 41b of the output shaft 4 and the hole 37 of the clutch 3. A coil spring CS is arranged between the end faces and urged toward the bearing Br1 side to connect the connecting cam 6 And the flat surface 43 of the output shaft 4 is accommodated in the inner peripheral surface 71 and the inner peripheral surface end 71a of the cam outer ring 7 and supported by the bearing Br1, and as shown in FIG. 7, the drive shaft 1, the output shaft 4, the coil Spring CS, clutch 3, and connecting cam 6 are connected together.

When the nut runner is in no-load operation or when the output shaft 4 is below a predetermined load torque,
The drive shaft 1 that is a carrier that supports the shaft of the planetary gear that is the output portion of the speed reducer is integrated with the coil spring CS, the clutch 3, the output shaft 4, and the connecting cam 6 in the hole 13 of the large diameter portion 12. As shown in FIGS. 7 and 9A, the connecting cam 6 that is positioned and held by the positioning shaft 5 by urging the clutch 3 toward the bearing Br1 by the coil spring CS as shown in FIGS. There is a gap V with the inner peripheral surface 71 of the cam outer ring 7, and it is not in contact. Therefore, the output shaft 4, the connecting cam 6, and the cam outer ring 7 are not connected, and the reaction force relaxation device does not operate and the output shaft 4 rotates. Can continue. FIG. 9A shows a cylindrical connecting cam 6a and a flat plate 43a corresponding to the cylindrical connecting cam, and the flat surface 43a has three places.

When the motor M is rotating and the tightening screw is seated and the output shaft 4 reaches a predetermined torque and stops rotating and a reaction force starts to be generated, the electromagnet SL is operated to activate the coil spring CS. , And the clutch 3 and the positioning shaft 5 are slid to the axial motor M side to release the integrated positioning of the positioning shaft 5 and the connecting cam 6, but the connecting cam 6 is not attached to the output shaft 4. Axial positioning is maintained by contacting the wheel SR and the washer W. The motor M that stops the nut runner is turned off simultaneously with the operation of the electromagnet SL or immediately after the operation of the electromagnet SL.

As shown in FIG. 9B, the output shaft 4 continues to transmit power in the clockwise direction for a short time after the operation of the electromagnet SL until the motor M is turned off, and the main body cases C1 and C2, the electromagnet SL, and The cam outer ring 7 is integrally rotated leftward about the axis of the output shaft 4. The end face of the connecting cam 6 whose positioning has been released is in contact with the inner peripheral surface end 71a of the cam outer ring 7 and is held by the cam outer ring 7 while rotating and rotating around the flat surface 43 of the output shaft 4 to rotate to the left by θ °. It moves and contacts the inner peripheral surface 71 of the cam outer ring 7. In this case, the sum of the distance U from the center of the output shaft 4 to the flat surface 43 and the outer diameter d of the connecting cam 6 is Rb, which is smaller than the radius Ra of the inner peripheral surface 71 of the cam outer ring 7, but the connecting cam 6 and the cam outer ring. 7, the contact portion of the inner peripheral surface 71 is swung outward from the central axis of the cam outer ring 7, becomes smaller than the radius Ra, and the gap V is eliminated. Therefore, the connecting cam 6 is pressed by the wedge action due to the reverse rotation of the output shaft 4 and the cam outer ring 7, and the cam outer ring 7 and the output shaft 4 are integrally connected to suppress or stop the rotation of the motor M. Reducing and mitigating the reaction force that occurs when tightening screws. In this case, the connection cam 6 rotates counterclockwise to push the flat surface 43 of the output shaft 4 to the right side to generate a stress that gives the output shaft 4 a right rotational force, and the reaction force of the cam outer ring 7 is increased by an amount corresponding to the stress. Can be expected to decrease. FIG. 9B shows a gear-type connecting cam 6b and a gear-type connecting cam corresponding 43b, and there are four planes 43b.

As shown in FIG. 7, arrow WW, the positioning of the positioning shaft 5 and the connecting cam 6 is released by the movement of the clutch 3 toward the motor M, but the tip shaft 51 of the positioning shaft 5 is Since the nut runner stops operation and the electromagnet SL is not operated, the clutch 3 is urged toward the bearing Br1 by the coil spring CS because it remains in the positioning hole 61 of the connection cam 6 and the electromagnet SL is inoperative. Positioning of the positioning shaft 5 and the gear type connecting cam 6 is easy.

The electromagnet SL can operate by detecting a change in the current value acting on the motor M, a change in the rotation speed of the output shaft 4, a torque value of the screw to be tightened, and the like. At the end of the screw tightening / loosening operation, the nut runner's operation stop power supply may be operated simultaneously with the operation of the electromagnet SL or automatically shut off after a short delay, or the switch Sw may be operated manually. The detection unit is not shown. Further, in the nut runner 200 of the second embodiment, a switch for operating or stopping the electromagnet SL alone is provided, the positioning of the positioning shaft 5 and the connecting cam 6 is released, and the screw tightening machine body is manually rotated. It is also possible to tighten the screws.

[Structure of third embodiment nut runner 300]
The nut runner 300 which concerns on 3rd Embodiment is shown to FIG. 10, FIG. 11, FIG. 12 (a), (b).

An output shaft 4 formed with a flat surface 43 that engages with the connecting cam 6 is loosely fitted to the output shaft 4 so as to be non-rotatable and slidable in the axial direction. And a cam outer ring 7 which accommodates the connecting cam 6 on the inner peripheral surface and rotatably supports the output shaft 4 and is fixed to the main body case C2. The output shaft 4 and the connecting cam 6 In the nut runner 100 that relaxes the reaction force of the nut runner by connecting or disconnecting the cam outer ring 7, the positioning shaft 5 of the connecting cam 6 is loosely fitted so as to be slidable only in the axial direction and positioned. A mechanism for moving the shaft 5 to the fixed holding position and the fixed holding release position of the connecting cam 6 is constituted by the slide ring 8 and the lever SW3.

The positioning shaft 5 is formed with a hole so that the pin SP is tightly fitted and loosely fitted into the hole 36 of the large-diameter portion 32 of the clutch 3, and is connected to the slide ring 8 by the pin SP.

The clutch 3 disposes a coil spring CS2 in the hole 36 of the large-diameter portion 32 and urges the positioning shaft 5 so as to be slidable. An oblong hole 39 is formed on the surface.

As shown in FIGS. 10 and 11, the slide ring 8 includes the clutch 3 and engages the lever SW3. The lever SW3 is slidably assembled to the main body case C2 and is operatively held in the main body case C1. Like to do.

[Operation of the third embodiment nut runner 300]
The nut runner is stopped, the lever SW3 is operated, the positioning shaft 5 is moved to the motor M side by the slide ring 8, the positioning of the positioning shaft 5 and the connecting cam 6 is released, and the nut runner is rotated manually to the right. Rotate. As shown in FIGS. 12 (a) and 12 (b), the main body cases C1 and C2 and the cam outer ring 7 are integrated with each other in a state where the output shaft 4 has stopped rotating due to resistance due to screw tightening or seating of the screw head. To rotate the axis of the output shaft 4 clockwise. The end face of the connection cam 6 whose positioning has been released is in contact with the inner peripheral surface end portion 71a of the cam outer ring 7, and is held by the cam outer ring 7 and revolves while rotating on the plane 43 of the output shaft 4 to the right by θ °. It rotates and contacts the inner peripheral surface 71 of the cam outer ring 7. In this case, the sum of the distance U from the center of the output shaft 4 to the flat surface 43 and the outer diameter d of the connecting cam 6 is Rb, which is smaller than the radius Ra of the inner peripheral surface 71 of the cam outer ring 7, but the connecting cam 6 and the cam outer ring. 7, the contact portion of the inner peripheral surface 71 is swung outward from the central axis of the cam outer ring 7, becomes smaller than the radius Ra, and the gap V is eliminated. Accordingly, the connecting cam 6 is pressed by the wedge action due to the stop of the output shaft 4 and the rotation of the cam outer ring 7 in the right direction, the cam outer ring 7 and the output shaft 4 are integrally connected, and the output shaft 4 is rotated to the right to rotate the screw. Tightening can be performed. 12 (a) shows the nut runner 100 and 12 (b) shows the nut runner 200.

To loosen the screw, stop the nut runner, operate the lever SW3, move the positioning shaft 5 to the motor M side by the slide ring 8, and release the positioning of the positioning shaft 5 and the connecting cam 6. Hold the nut runner body and rotate it counterclockwise. The main body cases C1 and C2 and the cam outer ring 7 are integrally rotated leftward about the axis of the output shaft 4. The connection cam 6 whose positioning has been released is also held by the cam outer ring 7 and revolves and rotates left by θ ° while rotating on the plane 43 of the output shaft 4 to come into contact with the inner peripheral surface 71 of the cam outer ring 7, 4 and the wedge action by the left rotation of the cam outer ring 7, the connecting cam 6 is pressed and the cam outer ring 7 and the output shaft 4 are integrally connected, and the output shaft 4 is rotated to the left to loosen the screw. it can

The present invention is not limited to the configuration examples described above, and can be implemented with modifications without departing from the spirit of the present invention. For example, the output shaft for tightening the screw and the gripping portion of the main body case can be mounted in a perpendicular direction to form an L-shaped tool, and the gripping portion can be lengthened to reduce the burden on the operator. In addition, it has the same structure as a drill for drilling work, it can be used for both purposes without distinguishing between a screw tightening tool and a drilling tool, and it occurs when the drill tip bites into the work material when drilling is completed. Reaction force is also reduced and relaxed. Therefore, even a beginner who has no work experience can use it safely.

Ba Storage battery Br1, Br2 Bearing CS, CS2, Coil spring C1, C2 Body case
G Reduction gear K Key M Motor SP Pin SR, SR2 Retaining ring SL Electromagnet So Tightening work tool Sw Switch Sw2, Sw3 ・ ・ Lever
W washer
1 Drive shaft
11 ・ ・ Shaft part, 12 ・ ・ Large diameter part, 13 ・ ・ Hole, 14 ・ ・ Retaining ring groove, 15 ・ ・ Cam groove,
16. ・ Small diameter part 17 ・ ・ Connection hole
2 Steel balls
3 Clutch
31 ·· Through hole, 32 ·· Large diameter part, 33 ·· Small diameter part, 34 ·· Cam groove, 35 ·· Power transmission surface, 36 ·· Hole 37 ·· Hole, 38 ·· Long stop 39 ·· Long Round hole
4 Output shaft
41a ... Front shaft, 41b ... Rear shaft, 42 ... Power transmission receiving surface, 43 ... Flat surface (43a ...
Compatible with cylindrical connection cams, 43b ... Compatible with gear type connection cams) 44 .... Retaining ring groove, 45 ... Hole, 46 ... Locking tool engaging part 47 ... Connection shaft part 48 ... Stopper
5 Positioning axis
51 .. Tip shaft
6 Connecting cam (6a ..Cylinder type connecting cam, 6b ..Gear type connecting cam)
61 ・ ・ Positioning hole 7 Cam outer ring
71 .... Inner peripheral surface, 71a ... End of inner peripheral surface, 72 ... Hole for bearing, 73 ...
8 Slide ring

Claims (3)

A connecting cam, a power transmission receiving surface, a flat surface that engages with the connecting cam, an output shaft on which a tightening / loosing tool is attached and detached, and a steel ball that forms a cam groove to transmit power are mounted. Power is transmitted to the drive shaft by the steel ball, and is freely loosely fitted within a certain range at the same time with circumferential swing and axial sliding, and a power transmission surface on the end face And a positioning shaft, the clutch holding the connecting cam by the positioning shaft, the power transmission surface, the power transmission receiving surface, and the connecting cam are accommodated in an inner peripheral surface, and the output shaft can be rotated. A reaction force reducing device for a nut runner comprising a cam outer ring that is supported by a bearing and fixed to a main body case, wherein the output shaft, the connecting cam, and the cam outer ring are connected or disconnected. The output shaft of the reduction device driven by a motor is directly coupled and fitted, and the flat surface that engages the connecting cam is formed, and the output shaft on which the tightening work tool is attached and detached, and the output shaft On the other hand, it is loosely fitted so as to be non-rotatable and slidable in the axial direction. The clutch includes the positioning shaft and holds the coupling cam. The clutch can be rotated in the circumferential direction on the outer periphery of the small-diameter portion of the clutch. And an electromagnet loosely fitted so as to be slidable in the axial direction, and the cam outer ring which is housed in the inner peripheral surface and rotatably receives the output shaft and is fixed to the main body case. And the reaction force relaxation apparatus of the nut runner characterized by connecting or disconnecting the said output shaft, the said connection cam, and the said cam outer ring | wheel. The flat surface that engages with the connecting cam is formed, the output shaft from which the tightening / loosening work tool is attached and detached, and loosely fitted so as to be non-rotatable and slidable in the axial direction with respect to the output shaft, The clutch having the positioning shaft and holding the connecting cam, and the cam outer ring that is housed in the inner peripheral surface of the clutch and that rotatably supports the output shaft and is fixed to the main body case. The output shaft, the connecting cam, and the cam outer ring are connected or disconnected, and the positioning shaft of the connecting cam is loosely slidable only in the axial direction. And a mechanism for moving the positioning shaft to a fixed holding release position and a fixed holding release position of the connecting cam. When the connecting cam is in the fixed holding release position, the screw tightening machine body is manually rotated to tighten the screw. Characterized by being able to Nutrunner according to claim 1.