JP4699229B2 - Tightening tool - Google Patents

Description

  The present invention relates to a tightening tool for tightening screws (bolts, nuts, screws, etc.). In particular, the present invention relates to a tightening tool including a clutch mechanism that limits torque transmitted from a motor to a tool.

A tightening tool that includes a clutch mechanism that limits torque transmitted from a motor to a tool and tightens screws with a specified tightening torque has been developed (for example, Patent Document 1). The clutch mechanism is configured using a pair of clutch members and a biasing unit that presses one of the pair of clutch members against the other. One of the pair of clutch members is connected to the motor side, and the other is connected to the tool side. In the clutch mechanism, torque from the motor is transmitted to the tool when the pair of clutch members engage with each other, and torque transmission from the motor to the tool is interrupted by releasing the engagement of the pair of clutch members.
An engaging part is formed in the pair of clutch members. The engaging portion maintains the engagement of the pair of clutch members when the torque applied to the tool is less than a predetermined value, and engages the pair of clutch members when the torque applied to the tool exceeds a predetermined value. It is configured to release.
Japanese Utility Model Publication No. 50-33759

The tightening tool receives a reaction force from the screws while tightening the screws. The operator needs to support the tightening tool against the reaction force received from the screws.
In the conventional tightening tool, the reaction force received from the screws rapidly increases from the time when the heads of the screws are seated on the base material to the time when the tightening torque reaches a predetermined value. The operator must continue to support the tightening tool against the reaction force that increases rapidly, and must continue to apply a relatively large force to the tightening tool.
The present invention solves the above problems. The present invention provides a tightening tool that is easily supported by an operator against a reaction force received from screws.

  The tightening tool embodied by the present invention is interposed between a motor, a tool that engages with screws, and the motor and the tool. By engaging each other, torque from the motor is applied to the tool. A pair of clutch members that transmit and release torque from the motor to the tool by disengaging each other and biasing means that presses at least one of the pair of clutch members against the other are provided. The pair of clutch members are provided with at least a first engagement portion and a second engagement portion. The first engagement portion maintains the engagement of the pair of clutch members when the torque applied to the tool is less than a first predetermined value, and the pair of clutch members when the torque applied to the tool is equal to or greater than the first predetermined value. The clutch member is disengaged. The second engagement portion maintains the engagement of the pair of clutch members when the torque applied to the tool is less than a second predetermined value that is greater than the first predetermined value, and the torque applied to the tool is the second. When the predetermined value or more is reached, the engagement of the pair of clutch members is released. The pair of clutch members are characterized in that the second engagement portion is engaged after the engagement of the first engagement portion is released.

In this tightening tool, the pair of clutch members are first engaged by the first engaging portion. The pair of clutch members are kept engaged until the torque applied from the screws to the tool (that is, the torque that the motor is actually applying and equal to the reaction force) reaches the first predetermined value. The When the torque applied from the screws to the tool reaches the first predetermined value, the engagement of the pair of clutch members is released. When the engagement of the pair of clutch members is released, torque transmission from the motor to the tool is interrupted. As a result, the reaction force that the tightening tool receives from the screws once decreases once it reaches the first predetermined value.
When the engagement by the first engagement portion is released, the pair of clutch members are subsequently engaged by the second engagement portion. The pair of clutch members are maintained in an engaged state until the torque applied to the tool from the screws reaches a second predetermined value. When the torque applied to the tool from the screws reaches the second predetermined value, the engagement of the pair of clutch members is released. At this stage, the tightening torque of the screws reaches a second predetermined value, and the reaction force received by the tightening tool from the screws also increases to the second predetermined value.
With this tightening tool, when the screws are tightened with the second predetermined value of the tightening torque, the engagement of the pair of clutches is temporarily released when the tightening torque reaches the first predetermined value. As a result, the reaction force received from the screws by the tightening tool once decreases when reaching the first predetermined value, and then increases to the second predetermined value. The reaction force that the tightening tool receives from the screws suddenly increases when the screws are seated, but is first limited to the first predetermined value, so that the operator continues to support the tightening tool without difficulty. be able to. Then, the reaction force that the tightening tool receives from the screws continuously increases to the second predetermined value, but since the worker can expect the increase, the worker continues to support the tightening tool without difficulty. be able to.

Each of the first engaging portion and the second engaging portion preferably has an inclined surface that comes into contact with the other clutch member. In this case, it is preferable that the inclined surface of the second engaging portion has a larger inclination angle than the inclined surface of the first engaging portion.
If an inclined surface that contacts the other clutch member is formed in each engaging portion, the first predetermined value and the second predetermined value described above can be adjusted by the inclination angle of the inclined surface. At this time, the inclined surface of the second engaging portion is formed to have a larger inclination angle than the inclined surface of the first engaging portion, so that the second predetermined value is higher than the first predetermined value. Can be determined to be larger.

In the above-described tightening tool, it is preferable that a motor control unit that stops driving of the motor when the engagement of the second engagement portions of the pair of clutch members is released is added.
Thereby, the operation of the motor can be stopped when the tightening torque of the screws reaches the second predetermined value.

The motor control means preferably stops the driving of the motor when the engagement of the pair of clutch members is released for a predetermined number of times.
In the above-described tightening tool, the pair of clutch members are disengaged a plurality of times until the tightening torque of the screws reaches the second predetermined value. Therefore, the number of times the pair of clutch members are disengaged is counted, and when the number of times reaches a predetermined number, the motor driving is stopped, so that the tightening torque of the screws is set to the prescribed torque. When it reaches, the motor operation can be stopped.

  According to the present invention, it is possible to embody a tightening tool that can be easily supported by an operator against a reaction force that the tightening tool receives from screws.

First, the main features of the embodiments described below are listed.
(Mode 1) The tightening tool includes a first clutch member and a second clutch member. The first clutch member is connected to the motor side, and the second clutch member is connected to the tool side.
(Mode 2) One of the first clutch member and the second clutch member is provided with a first engagement portion, a second engagement portion, and a third engagement portion. The other of the first clutch member and the second clutch member is provided with a contact portion that contacts the first engagement portion, the second engagement portion, and the third engagement portion. The abutting portion abuts on any of the first engaging portion, the second engaging portion, and the third engaging portion in accordance with the relative rotational position of the first clutch member and the second clutch member.
(Mode 3) The tightening tool includes means for detecting that the engagement of the pair of clutch members has been released.

FIG. 1 shows an internal configuration of the electric driver 10 according to the first embodiment. As shown in FIG. 1, the electric driver 10 includes a housing 12, a motor 14 built in the housing, a tool chuck 16 supported so as to be rotatable with respect to the housing 12, and rotatable with respect to the housing 12. , A spindle 15 supported by the motor 15, a speed reducer 22 that transmits the rotational torque of the motor 14 to the spindle 15, and a clutch mechanism 20. The tool chuck 16 is fixed to the spindle 15. The tool chuck 16 is configured to be detachable from a tool (for example, a driver bit) 18 that engages with screws (bolts, nuts, screws, etc.). The electric driver 10 rotates the driver bit 18 mounted on the tool chuck 16 by rotating the motor 14.
The electric driver 10 serves as a power source for a trigger switch 24 operated by an operator, a display lamp 26 provided so as to be visible to the operator, a control circuit 28 for controlling operations of the motor 14, the display lamp 26, and the like. A connector 30 for connecting a battery pack (shown in FIG. 9) 100 is provided.

  FIG. 2 shows an enlarged view of the speed reducer 22 and the clutch mechanism 20 of the electric driver 10. As shown in FIG. 2, the speed reducer 22 includes a first sun gear 32, three first satellite gears 34 (some of which are not shown), an internal gear 36, a second sun gear 38, and three A second satellite gear (not shown) 40 and an output member 42 are provided. The first sun gear 32 is fixed to the output shaft 14 a of the motor 14. The first satellite gear 34 meshes with both the first sun gear 32 and the internal gear 36, and revolves around the first sun gear 32 while rotating by receiving the rotation of the first sun gear 32. A rotation shaft 35 of the first satellite gear 34 is fixed to the second sun gear 38, and is rotated by following the revolution movement of the first satellite gear 34. The second satellite gear 40 meshes with both the second sun gear 38 and the internal gear 36 and revolves around the second sun gear 38 while rotating by receiving the rotation of the second sun gear 38. The rotation shaft 41 of the second satellite gear 40 is fixed to the output member 42 and rotates following the revolution movement of the second satellite gear 40. Thus, the speed reducer 22 has a planetary gear structure provided in two stages, decelerates the rotational motion of the motor 14 at a predetermined reduction ratio, and outputs it to the rotational motion of the output member 42. That is, the rotational torque of the output member 42 is amplified to the reciprocal times the reduction ratio with respect to the rotational torque of the motor 14.

The clutch mechanism 20 includes a first clutch member 56, a second clutch member 58, three contact spheres 64 (partially omitted), a compression spring 62, and three connection spheres 63 (partially omitted). A spring restraining member 66 and an adjusting member 68 are provided.
The first clutch member 56 is fixed to the output member 42 of the speed reducer 22 and rotates together with the output member 42 as the motor 14 rotates. On the other hand, the second clutch member 58 is provided on the spindle 15. The second clutch member 58 is connected to the spindle 15 via a connecting sphere 63, is connected to the spindle 15 so as not to rotate relative to the spindle 15, and is supported so as to be movable in the axial direction of the spindle 15. .
The first clutch member 56 is formed with a first facing surface 56a. The second clutch member 58 has a second facing surface 58a. The first facing surface 56a of the first clutch member 56 and the second facing surface 58a of the second clutch member 58 face each other. The contact sphere 64 is interposed between the first facing surface 56 a of the first clutch member 56 and the second facing surface 58 a of the second clutch member 58. The compression spring 62 biases the second clutch member 58 toward the first clutch member 56. The first clutch member 56 and the second clutch member 58 are engaged with each other with respect to the rotation direction via the contact sphere 64. When the first clutch member 56 and the second clutch member 58 are engaged with each other, the torque from the motor 14 is transmitted to the spindle 15 side, and when the mutual engagement is released, the torque from the motor 14 to the spindle 15 is transmitted. Block transmission.
The spring restraining member 66 restrains the end of the compression spring 62 on the side opposite to the second clutch member 58. The adjustment member 68 is screwed into the side surface of the spindle 15 and moves in the axial direction of the spindle 15 by rotating. As the adjusting member 68 moves along the axial direction of the spindle 15, the spring restraining member 66 also moves along the axial direction of the spindle 15. The operator can adjust the pressing force with which the compression spring 62 presses the second clutch member 58 toward the first clutch member 56 by rotating the adjustment member 68.

  As shown in FIG. 2, the electric driver 10 includes an interlocking member 54 that moves as the second clutch member 58 moves, a detection switch 52 that turns on and off as the interlocking member 54 moves, and an interlocking member 54. A biasing spring 60 biasing toward the detection switch 52 is provided. In a state where the second clutch member 58 is located on the first clutch member 56 side, the interlocking member 54 receives the urging force from the urging spring 60 and is located on the detection switch 52 side. At this time, the detection switch 52 is turned on. That is, while the first clutch member 56 and the second clutch member 58 are engaged, the detection switch 52 is turned on. On the other hand, when the second clutch member 58 moves away from the first clutch member 56, the interlocking member 54 moves away from the detection switch 52. At this time, the detection switch 52 is turned off. That is, the detection switch 52 is turned off in a state where the engagement of the first clutch member 56 and the second clutch member 58 is released.

Next, the first opposing surface 56a of the first clutch member 56 and the second opposing surface 58a of the second clutch member 58 will be described.
FIG. 3 shows the first clutch member 56 viewed from the first facing surface 56a side. As shown in FIG. 3, the first facing surface 56 a of the first clutch member 56 is formed with three recesses 57 for loosely fitting the contact spheres 64. The recess 57 is formed in a substantially hemispherical shape. The three recessed portions 57 are arranged at equal intervals along the circumferential direction. The contact sphere 64 is held by the recess 57 of the first clutch member 56 and rotates substantially integrally with the first clutch member 56. Therefore, the contact sphere 64 can be regarded as a part of the first clutch member 56, and the first clutch member 56 and the contact sphere 64 may be formed integrally.
FIG. 4 shows the second clutch member 58 viewed from the second facing surface 58a side. FIG. 5 shows an expanded cross section along the circular cutting line V shown in FIG. As shown in FIGS. 4 and 5, a groove portion 58 b extending along the circumferential direction is formed on the second facing surface 58 a of the second clutch member 58. The groove portion 58 b is provided at a position facing the concave portion 57 of the first clutch member 56. The groove portion 58b is formed with three sets of engaging protrusion groups 59a, 59b, 59c, each of which includes a first engaging protrusion 59a, a second engaging protrusion 59b, and a third engaging protrusion 59c. Yes. The three sets of engaging projections 59a, 59b, 59c are arranged at equal intervals along the circumferential direction.
FIG. 6 shows an enlarged view of the set of engaging protrusions 59a, 59b, 59c. As shown in FIG. 6, in the set of engaging protrusion groups 59 a, 59 b, 59 c, the first engaging protrusions along the direction in which the first clutch member 56 rotates relative to the second clutch member 58. 59a, the second engagement protrusion 59b, and the third engagement protrusion 59c are arranged in this order.
Contact slopes 61a, 61b, 61c are formed on the respective engaging projections 59a, 59b, 59c. When the first clutch member 56 is rotated by the motor 14, the contact spherical body 64 held on the first clutch member 56 side contacts the contact slopes 61a, 61b, 61c. In the first engagement protrusion 59a, a first contact slope 61a is formed at an inclination angle θ1. In the second engagement protrusion 59b, the second contact slope 61b is formed at an inclination angle θ2. In the third engagement protrusion 59c, a third contact slope 61c is formed at an inclination angle θ3. The magnitude relationship between the inclination angles θ1, θ2, and θ3 is θ1 <θ2 <θ3.

The operation of the clutch mechanism 20 will be described with reference to FIGS. 7 and 8 show the first clutch member 56 and the second clutch member 58 developed in the circumferential direction. As shown in FIG. 7, when the first clutch member 56 is rotated by the motor 14, the contact sphere 64 loosely fitted in the recess 57 of the first clutch member 56 is changed to the first engagement of the second clutch member 58. It contacts the first contact slope 61a of the mating projection 59a. The contact sphere 64 tries to get over the first engagement protrusion 59a, but the urging force of the compression spring 62 prevents the contact sphere 64 from getting over the first engagement protrusion 59a. The first clutch member 56 and the second clutch member 58 are engaged with each other in the rotational direction, and both rotate together. Thereby, the torque output from the motor 14 is transmitted to the spindle 15 through the clutch mechanism 20. At this time, the detection switch 52 is turned on.
On the other hand, as shown in FIG. 8, when a torque that restricts rotation is applied to the spindle 15, the abutting sphere 64 gets over the first engaging protrusion 59 a against the urging force of the compression spring 62. At this time, the first clutch member 56 and the second clutch member 58 are disengaged in the rotational direction, and torque transmission from the motor 14 to the spindle 15 is interrupted. That is, when the screw is tightened by the electric driver 10, the torque transmission between the first clutch member 56 and the second clutch member 58 is cut off when the tightening torque reaches a first predetermined value (for example, R1). . The first torque R1 at this time is mainly determined according to the urging force of the compression spring 62 and the inclination angle θ1 of the first contact slope 61a. The first torque R1 increases as the inclination angle θ1 of the first contact slope 61a increases.

  When the abutting sphere 64 gets over the first engaging protrusion 59a, the first clutch member 56 rotates relative to the second clutch member 58, and the abutting sphere 64 becomes the second contact of the second engaging protrusion 59b. It contacts the contact slope 61b. Thereby, the 1st clutch member 56 and the 2nd clutch member 58 are engaged again regarding a rotation direction. Then, when the tightening torque applied to the screws reaches a second predetermined value (for example, R2), the contact sphere 64 gets over the second engagement protrusion 59b. When the contact sphere 64 gets over the second engagement protrusion 59b, the torque transmission between the first clutch member 56 and the second clutch member 58 is cut off again. The second torque R2 at this time is mainly determined according to the urging force of the compression spring 62 and the inclination angle θ2 of the second contact slope 61b. Since the inclination angle θ2 of the second contact slope 61b is larger than the inclination angle θ1 of the first contact slope 61a, the second torque R2 is larger than the first torque R1.

When the abutting sphere 64 gets over the second engaging protrusion 59b, the first clutch member 56 rotates relative to the second clutch member 58, and the abutting sphere 64 becomes the third contact of the third engaging protrusion 59c. It contacts the contact slope 61c. Thereby, the 1st clutch member 56 and the 2nd clutch member 58 are engaged again regarding a rotation direction. Then, when the tightening torque applied to the screws reaches a third predetermined value (for example, R3), the contact sphere 64 gets over the third engagement protrusion 59c. When the contact sphere 64 gets over the third engagement protrusion 59c, the torque transmission between the first clutch member 56 and the second clutch member 58 is interrupted again. The third torque R3 at this time is mainly determined according to the urging force of the compression spring 62 and the inclination angle θ3 of the third contact slope 61c. Since the inclination angle θ3 of the third abutting slope 61c is larger than the inclination angle θ2 of the second abutting slope 61b, the third torque R3 is larger than the second torque R2. That is, the relationship is first torque R1 <second torque R2 <third torque R3.
When the contact sphere 64 gets over the third engagement protrusion 59bc, the contact sphere 64 again contacts the first contact slope 61a of the first engagement protrusion 59a, and the clutch mechanism 20 returns to the state shown in FIG.
Thus, in the clutch mechanism 20, when the torque applied to the screws becomes the first torque R1, the torque transmission is temporarily interrupted, and then the torque applied to the screws is changed to the second torque R2. At that time, torque transmission is temporarily interrupted, and then torque transmission is interrupted when the tightening torque applied to the screws becomes the third torque R3.

FIG. 9 schematically shows a circuit configuration of the electric driver 10. As shown in FIG. 9, in the electric driver 10, power is supplied from the battery pack 100 connected to the connector 30 to the motor 14 and power is supplied to the control circuit 28. A semiconductor switch 80 is inserted on a circuit that connects the motor 14 to the battery pack 100 via the connector 30. The semiconductor switch 80 is switched between an on state and an off state by a drive signal output from the control circuit 28.
The control circuit 28 includes a microcomputer, a constant voltage power supply circuit, and the like. A trigger switch 24, a detection switch 52, and a display lamp 26 are connected to the control circuit 28. The control circuit 28 controls the operation of the semiconductor switch 80 and the display lamp 26 based on the output signal of the trigger switch 24 and the output signal of the detection switch 52.

FIG. 10 is a time chart showing the operation of each part of the electric driver 10 over time. The operation of the control circuit 28 will be described with reference to FIG. (A) in FIG. 10 shows the on / off state of the trigger switch 24. (B) shows the on / off state of the semiconductor switch 80. (C) shows the reaction force torque that the driver bit 18 receives from the screws. The reaction force torque that the driver bit 18 receives from the screws is substantially equal to the torque that the driver bit 18 applies to the screws. (D) shows the on / off state of the detection switch 52. (E) shows the on / off state of the display lamp 26.
First, the operator engages the driver bit 18 with the screw and turns on the trigger switch 24. This time is defined as time t1. When the trigger switch 24 is turned on at time t1, the control circuit 28 outputs a drive signal to the semiconductor switch 80 to turn on the semiconductor switch 80. When the semiconductor switch 80 is turned on, the motor 14 is electrically connected to the battery pack 100 (specifically, a battery built in the battery pack), and the motor 14 starts rotating. In the clutch mechanism 20, the contact sphere 64 held on the first clutch member 56 side contacts the first contact slope 61 a of the first engagement protrusion 59 a provided on the second clutch member 58 side. The torque from the motor 14 is transmitted to the spindle 15 side. The driver bit 18 is rotated by the motor 14, and the screws are screwed into the base material. Note that when the operator stops turning on the trigger switch 24, the control circuit 28 stops outputting the drive signal to the semiconductor switch 80, and the motor 14 stops. Here, it is assumed that the operator continues to turn on the trigger switch 24 until time t5 described later.

As shown in FIG. 10C, the reaction force torque that the driver bit 18 receives from the screws changes at a relatively small value until the screw head is seated, and the screw head is seated. It increases rapidly from the time point (X in the figure). At time t2, when the reaction torque received by the driver bit 18 from the screw, that is, the tightening torque applied to the screw, reaches the first torque R1, the contact ball 64 gets over the first engagement protrusion 59a, and Torque transmission between the first clutch member 56 and the second clutch member 58 is interrupted. The contact sphere 64 that has passed over the first engagement protrusion 59a then contacts the second contact slope 61b of the second engagement protrusion 59b. Accordingly, the first clutch member 56 and the second clutch member 58 are engaged again, and the torque output from the motor 14 is transmitted to the spindle 15 side.
At time t3, when the reaction torque received by the driver bit 18 from the screw, that is, the tightening torque of the screw reaches the second torque R2, the contact ball 64 gets over the second engagement protrusion 59b, and the first clutch member Torque transmission between 56 and the second clutch member 58 is interrupted. The contact sphere 64 that has passed over the second engagement protrusion 59b then contacts the third contact inclined surface 61c of the third engagement protrusion 59c. Accordingly, the first clutch member 56 and the second clutch member 58 are engaged again, and the torque output from the motor 14 is transmitted to the spindle 15 side.
When the reaction force torque that the driver bit 18 receives from the screw at time t4, that is, the tightening torque of the screw reaches the third torque R3, the contact sphere 64 gets over the third engagement protrusion 59c, and the first clutch member Torque transmission between 56 and the second clutch member 58 is interrupted.
Thus, in the clutch mechanism 20, when the screw tightening torque reaches the first torque R1, when the screw tightening torque reaches the second torque R2, and when the screw tightening torque is Torque transmission is temporarily interrupted for three times when the third torque R3 is reached. Although the reaction torque received by the electric screwdriver 10 from the screws suddenly increases when the screws are seated, the operator first supports the tightening tool reasonably by being limited to the first torque R1. You can continue. The reaction force that the electric driver 10 receives from the screws subsequently increases to a second torque R2 that is larger than the first torque R1, but since the operator can expect the increase, the operator presses the tightening tool. You can continue to support without unreasonableness. The reaction force that the electric driver 10 receives from the screws subsequently increases to the third torque R3 that is larger than the second torque R2, but the operator can expect the increase, and the operator tightens the torque. The tool can be supported without difficulty. The operator can continue to support the electric driver 10 without difficulty against the reaction force torque received from the screws.

As shown in FIG. 10D, the detection switch 52 is temporarily turned off when the clutch mechanism 20 interrupts torque transmission (time t2, t3, t4). The time (time t2) when the detection switch 52 is turned off for the first time corresponds to the time when the tightening torque of the screws reaches the first torque R1. The time (time t3) when the detection switch 52 is turned off for the second time corresponds to the time when the tightening torque of the screws reaches the second torque R2. The time (time t4) when the detection switch 52 is turned off for the third time indicates the time when the tightening torque of the screws reaches the third torque R3. The control circuit 28 counts the number of times that the detection switch 52 is turned off. When the detection switch 52 is turned off for the third time, the control circuit 28 turns on the semiconductor switch 80 as shown in FIG. While turning off, the display lamp is turned on as shown in FIG. Accordingly, the rotation of the motor 14 is stopped, and the operator is notified that the screw tightening torque has reached the third torque R3. After confirming that the display lamp 26 is turned on, the worker turns off the trigger switch 24 (time t5). The control circuit 28 turns off the display lamp 26 when the trigger switch 24 is turned off. As described above, the tightening tool 10 ends the operation after tightening the screws with the tightening torque equal to the third torque R3. As described above, the value of the third torque R3 can be adjusted by operating the adjusting member 68. By setting the value of the third torque R3 equal to the target value of the tightening torque, the screw can be tightened with the target tightening torque. Further, by adjusting the value of the third torque R3, the values of the first torque R2 and the second torque R2 are also adjusted.
Note that the number of times the detection switch 52 is turned off, which the control circuit 28 determines that the tightening of the screws has been completed, corresponds to the number of types of the engagement protrusions 59a, 59b, 59c provided in the clutch mechanism 20. Therefore, for example, when the clutch mechanism 20 is provided with two types of engagement protrusions, the control circuit 28 completes the tightening of the screws when the detection switch 52 is turned off for the second time. It will be judged that.

As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, the detection switch may detect only when the contact sphere 64 gets over the third engagement protrusion 59c. In this case, for example, the height of the third engagement protrusion 59c is made different from the height of the other engagement protrusions 59a and 59b, and the detection is performed only when the contact sphere 64 gets over the third engagement protrusion 59c. The switch 52 can be configured to be turned off.
The configuration of the first facing surface 56a of the first clutch member 56 and the configuration of the second facing surface 56a of the second clutch member 58 can be reversed. That is, the engagement protrusions 59a, 59b, 59c may be provided on the first clutch member 56 side, and the contact sphere 64 may be held on the second clutch member 58 side. The contact sphere 64 can also be provided integrally with the clutch members 56 and 58.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology illustrated in this specification or the drawings achieves a plurality of objects at the same time, and achieving one of the objects itself has technical utility.

The figure which shows the structure of an electric driver. The figure which expands and shows the structure of a reduction gear and a clutch mechanism. The figure which looked at the 1st clutch member from the 1st counter surface side. The figure seen from the 2nd opposing surface side of the 2nd clutch member. The figure which expands and shows the cross section by the V line of FIG. The figure which expands and shows an engagement protrusion part group. The figure which shows the state which the 1st clutch member and the 2nd clutch member are engaging. The figure which shows the state by which the 1st clutch member and the 2nd clutch member were disengaged. The figure which shows typically the electric constitution of an electric driver. The time chart which shows the flow of operation | movement of an electric driver.

Explanation of symbols

10 .. Electric screwdriver 12.. Housing 14... Motor 15... Spindle 16... Tool chuck 18.
20, clutch mechanism 22, reduction gear 24, trigger switch 26, display lamp 28, control circuit 30, connector 52, detection switch 56, first clutch member 57, recess 58, second. Clutch member 58b .... grooves 59a, 59b, 59c..engagement projections 61a, 61b, 61c .... contact slope 62..compression spring 63..connecting sphere 64..contact sphere.

Claims (3)

A motor,
A tool that engages with screws,
A pair of motors are interposed between the tool and transmit torque from the motor to the tool by engaging with each other, and cut off torque transmission from the motor to the tool by disengaging each other. A clutch member;
Urging means for pressing at least one of the pair of clutch members against the other,
The pair of clutch members are provided with at least a first engagement portion and a second engagement portion,
The first engagement portion maintains the engagement of the pair of clutch members when the torque applied to the tool is less than a first predetermined value, and the pair of clutch members when the torque applied to the tool is equal to or greater than the first predetermined value. Disengage the clutch member,
The second engagement portion maintains the engagement of the pair of clutch members when the torque applied to the tool is less than a second predetermined value that is greater than the first predetermined value, and the torque applied to the tool is the second. When a predetermined value or more is reached, the engagement of the pair of clutch members is released,
The pair of clutch members is a tightening tool in which the second engaging portion is engaged after the engagement of the first engaging portion is released. Each of the first engaging portion and the second engaging portion is formed with an inclined surface that comes into contact with the other clutch member,
2. The tightening tool according to claim 1, wherein the inclined surface of the second engaging portion has a larger inclination angle than the inclined surface of the first engaging portion.   3. The tightening tool according to claim 1, further comprising motor control means for stopping driving of the motor when the engagement of the second engagement portion of the pair of clutch members is released. .

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