JP5463987B2 - Electric tool - Google Patents

Description

  The present invention relates to an arrangement structure of a forward / reverse selector switch for switching between a forward rotation and a reverse rotation of a motor rotation direction of an electric tool.

  The forward / reverse selector switch of the conventional electric tool is used when the motor is switched between forward rotation and reverse rotation. The forward / reverse selector switch is configured so that it can be operated almost perpendicularly to the motor axial direction. The forward / reverse selector switch is installed in the space behind the motor of the housing in consideration of the installation space of the forward / reverse selector switch. Often placed. In the technique of Patent Document 1, the forward / reverse selector switch is arranged on the rear side of the motor.

Japanese Utility Model Publication No. 1-170569

  For example, the electric power tool hangs the electric tool from the ceiling with a stretchable rubber or the like in a factory line of a flow work, and performs a work such as screw tightening on a material to be fastened while grasping with a dominant hand. At this time, when the screw has entered the material to be tightened by mistake, the operator switches from forward rotation to reverse rotation with the forward / reverse selector switch, once loosens the screw, and again from reverse to forward rotation with the forward / reverse selector switch. Switch and perform regular tightening work. During this work, if the operability of the forward / reverse selector switch is poor, work time is lost, and the operator becomes tired. Therefore, further improvement in the operability of the forward / reverse selector switch has been desired.

  As a result of reviewing the arrangement of the forward / reverse selector switch of the prior art by the inventors of the present application, if the forward / reverse selector switch is arranged in the space behind the motor with respect to the axial direction of the motor, the main body is gripped. It has been found that the length from the position (gripping position) to the forward / reverse selector switch becomes longer. Therefore, it has been found that many workers are working to release the hand holding the grip portion of the housing, operate the forward / reverse switching switch, and then grip the grip portion again.

  This invention is made | formed in view of the said background, The objective is to provide the electric tool which comprised the full length compactly by devising arrangement | positioning of the forward / reverse selector switch.

  Another object of the present invention is to provide an electric tool that can easily operate a forward / reverse selector switch while holding a housing of the electric tool.

  Still another object of the present invention is to provide an electric tool that can improve operability without being influenced by the dominant hand, can shorten the working time, and does not get tired even when used for a long time.

  The characteristics of representative ones of the inventions disclosed in the present application will be described as follows.

According to one aspect of the present invention, there is provided an electric tool having a motor, a cylindrical housing that houses the motor, and a tip tool holding portion that protrudes from the front end of the housing for switching the rotation direction of the motor. The switching operation portion of the forward / reverse selector switch was provided on the outside in the radial direction of the motor. In addition, a start switch for rotating the motor is provided, the switch lever of the forward / reverse selector switch and the switch operating part of the start switch are arranged symmetrically with respect to the motor rotation axis, and the motor is sandwiched between the forward / reverse selector switch and the start switch. Arranged to be.

According to another feature of the present invention, the switching operation portion projects outward from the housing and is provided at a position overlapping the motor in the axial direction. The switch lever protrudes from the housing and is provided at a position that overlaps the motor in the axial direction.

According to still another aspect of the present invention, the forward / reverse selector switch is operated in a direction perpendicular to the longitudinal direction of the cylindrical housing, and the switching operation unit is swung to switch between normal rotation and reverse rotation, or the switching operation unit. Is configured to switch between forward rotation and reverse rotation. The forward / reverse changeover switch is operated in a direction parallel to the longitudinal direction of the cylindrical housing, and a forward / reverse changeover switch is provided with a push button, and is configured to switch between forward rotation and reverse rotation by pressing the pushbutton.

  According to the invention of claim 1, since the switching operation lever of the forward / reverse selector switch for switching the rotation direction of the motor is provided on the outer side in the radial direction of the motor, the mounting space for the forward / reverse selector switch is set to the axial direction of the motor. The length from the position where the main body is gripped to the forward / reverse selector switch can be shortened, and the forward / reverse selector switch can be arranged at a position where only the thumb is moved in the posture gripped by the housing.

According to the invention of claim 2, since the switch lever of the forward / reverse selector switch and the switching operation portion of the start switch are arranged at symmetrical positions with respect to the rotation axis of the motor, the configuration of the housing can be made symmetrical. Good operability can be achieved without changing between right-handed and left-handed. Furthermore, the front and rear length of the housing can be shortened, and a compact electric tool can be realized.

According to the invention of claim 3, since the switching operation portion is provided at a position overlapping with the motor in the axial direction, the forward / reverse switching switch can be easily operated in the posture of gripping the housing, and the switching work time is shortened. Therefore, it is possible to realize an electric tool that does not get tired even if it is used for a long time.

  According to the invention of claim 4, since the switch lever is provided at a position overlapping with the motor in the axial direction, the switch lever can be easily operated while grasping the grip portion of the housing, and a user-friendly electric tool is provided. realizable.

  According to the invention of claim 5, since the switch lever protrudes from the housing and is provided at a position overlapping the motor in the axial direction, a forward / reverse selector switch that can be easily operated in a posture held by the housing can be realized.

According to the invention of claim 6, since the forward / reverse selector switch swings the switching operation portion to switch between forward rotation and reverse rotation, the forward / reverse selector switch is operated by moving only the thumb in the posture gripped by the housing. be able to.

According to the seventh aspect of the present invention, the forward / reverse selector switch slides the switching operation portion to switch between forward rotation and reverse rotation. Therefore, the forward / reverse selector switch is operated by moving only the thumb in the posture held by the housing. Can do.

  According to the invention of claim 8, since the forward / reverse selector switch is operated in a direction parallel to the longitudinal direction of the cylindrical housing, a forward / reverse selector switch that can be easily operated can be realized.

  According to the ninth aspect of the present invention, since the forward / reverse selector switch is provided with a push button and the forward rotation and the reverse rotation are switched by pressing the push button, an easy-to-use electric tool can be realized.

  According to the invention of claim 10, since the switch having the operation portion exposed to the outer periphery is provided in the electric power tool, the space for attaching the forward / reverse selector switch can be provided in parallel with the axial direction of the motor.

  According to the invention of claim 11, the housing has a tail portion having a diameter larger than that of the grip portion behind the portion to be gripped, and the operation portion projects forward from the tail portion.

  According to the invention of claim 12, since the operation portion can be operated in a direction intersecting with the front-rear direction, the structure of the housing can be made symmetrical, and good operability is realized without changing between right-handed and left-handed. it can.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

It is a longitudinal cross-sectional view of the electric driver which concerns on the Example of this invention. 1 is a side view of an electric driver according to an embodiment of the present invention. It is a bottom view of the electric driver which concerns on the Example of this invention. FIG. 3 is a cross-sectional view taken along a line AA in FIG. 2 and a rear view from the AA part. It is a partial bottom view which shows operation | movement of the switching operation lever 20 of FIG. It is a functional block diagram which shows the drive control system of the motor 5 of the electric driver which concerns on the Example of this invention. It is a partial bottom view of the electric driver which concerns on 2nd Example of this invention. FIG. 8 is a cross-sectional view of a BB portion in FIG. It is a partial bottom view of the electric driver which concerns on the 3rd Example of this invention. FIG. 10 is a cross-sectional view taken along a line CC in FIG. 9 and a view seen behind the line CC.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same portions are denoted by the same reference numerals, and repeated description is omitted. Further, in the present specification, description will be made assuming that the vertical and front-rear and left-right directions are the directions shown in FIGS.

  FIG. 1 is a sectional view of an electric driver 1 according to an embodiment of the present invention. The electric driver 1 includes a motor 5, a housing 2 that houses the motor 5, a reduction mechanism 50 that reduces the rotation of the motor 5 at a predetermined reduction ratio, and a clutch mechanism 70 that is provided in front of the reduction mechanism 50. And a case 3 that is attached to the front of the clutch mechanism 70 and holds the shaft 7 rotatably, and a socket 8 that extends forward from the case 3 to attach a tip tool. In the present embodiment, the motor 5, the speed reduction mechanism 50, the clutch mechanism 70, the shaft 7 and the tip tool are arranged on the same axis. The speed reduction mechanism 50 decelerates the rotation of the motor 5 at a predetermined ratio and transmits it to the clutch mechanism 70. For example, the speed reduction mechanism 50 uses a two-stage planetary gear. A clutch mechanism 70 is provided in front of the speed reduction mechanism 50 to release rotation transmission between the speed reduction mechanism 50 and the shaft 7 when a constant load torque is applied to the tip tool. The magnitude of the load torque when the clutch mechanism 70 is actuated to release the rotation transmission between the speed reduction mechanism 50 and the shaft 7 can be adjusted by rotating the dial 22. The dial 22 is a transparent protective member, and is a member for facilitating the rotation of the clutch ring 4. The clutch ring 4 is movable in the axial direction by contacting the front end of the spring 77 and screwing with a screw portion formed on the outer periphery of the case 3. When the clutch ring 4 is rotated, the spring 77 is compressed, and the pressing force of the ball 71 can be increased.

  The housing 2 that accommodates the motor 5 is formed in a cylindrical shape, and is configured to be split right and left on a vertical plane that passes through an extension line of the rotating shaft 5d of the motor 5. A plurality of screw bosses (not shown) are formed on the right housing, and are fixed to the left housing with screws (not shown). As described above, the housing portion is divided into left and right parts, so that the motor 5, the speed reduction mechanism 50, the clutch mechanism 70, the switch lever 10, the forward / reverse changeover switch 21, the circuit components, the circuit board, and the like are arranged in one housing. After that, it can be easily assembled by covering the other housing and screwing.

  A so-called inner rotor type brushless DC motor 5 is accommodated in the vicinity of the center of the housing 2. In the motor 5, a rotor 5a having a permanent magnet is attached to a rotating shaft 5d, and a stator 5b having a coil 5c is fixed to the housing 2 side. On the front side of the motor 5, a small cooling fan 6 is provided coaxially with the rotating shaft 5d. As the motor 5 rotates, the cooling fan 6 also rotates, sucks outside air from an air intake port (not shown) provided behind the housing 2, and flows around the switching element 16 mounted on the inverter board 27 and the motor 5. Then, it is cooled and discharged from a discharge port (not shown) provided on the front side of the housing 2. The rotating shaft 5d of the motor 5 is rotatably held by two bearings 19a and 19b. The bearings 19a and 19b are respectively held by fixing ribs 2a and 2b formed to protrude from the side wall of the housing 2.

  Three circuit boards including a power supply board 26, an inverter board 27, and a control board 28 are mounted on the rear end portion of the housing 2. A power supply circuit 18 is mounted on the power supply board 26. A power cord 29a is connected to the housing 2 via a connector 29b, and AC power of, for example, 50 Hz and 100 V is supplied to the power circuit 18 from the outside. The power supply board 26 is provided with a power supply circuit 18 for rectifying supplied AC power into predetermined DC power. The rectified DC power is sequentially supplied to each phase of the coil 5c of the motor 5 at predetermined intervals by an inverter circuit constituted by a switching element 16 such as an FET (field effect transistor). As the configuration of the inverter circuit and the control circuit 17 for controlling the inverter circuit mounted on the inverter board 27, a known circuit for controlling the brushless DC motor can be used. Details of the control circuit will be described later.

  An activation switch for turning on / off the rotation of the motor 5 is provided on the upper portion of the housing 2. The activation switch includes a switch lever 10 that can swing with respect to the housing 2 with respect to the rotation shaft 12, a spring 11 that biases the switch lever 10 in a predetermined swing direction, and a switch with respect to the rotation shaft 12. The lever 10 includes a permanent magnet 13 attached to an end portion 10b opposite to the pressing surface 10a, and a Hall element 14 provided at a position facing the permanent magnet 13. The Hall element 14 is mounted on the substrate 15. When the pressing surface 10a of the switch lever 10 protruding outward from the housing 2 is pressed and the switch lever 10 is moved in a direction in which the spring 11 is compressed, the switch lever 10 is counterclockwise around the rotation shaft 12 in FIG. Oscillates in the direction (rotates by a small angle), and the distance between the permanent magnet 13 and the Hall element 14 decreases. As a result, the Hall element 14 is affected by the magnetic field generated from the permanent magnet 13 and the output of the Hall element 14 becomes high, and a signal is transmitted from the Hall element 14 to a control unit described later. Thus, by moving the switch lever 10, the Hall element 14 detects the proximity and separation of the magnets, so that the rotation of the motor 5 can be turned on or off. Since the mechanism of this start switch is magnetically detected by the Hall element 14 using the permanent magnet 13 without having a mechanical contact, the contact is not deteriorated and can be operated stably for a long period of time. Can do.

  A forward / reverse selector switch 21 for switching the rotational direction of the motor 5 between forward rotation and reverse rotation is provided below the motor 5 of the housing 2. The forward / reverse selector switch 21 has the switching operation lever 20 on the outer peripheral side of the middle part of the housing 2 in which the motor 5 is accommodated, and the direction of the rotating shaft 5d of the motor 5 and the extending direction of the switching operation lever 20 are substantially parallel. It is provided to become. In FIG. 2, it will be understood that the axis 25a and the center line 25b of the switching operation lever 20 are substantially parallel. The switching operation lever 20 is provided so as to protrude from the rear to the front in the direction of the rotation shaft 5d and from the housing 2 to the outside. A display unit 23 is provided behind the forward / reverse selector switch 21. The display unit 23 is disposed so as to be visible from the lower surface of the main body, and can display, for example, the current rotation speed and torque.

  Here, if the length portion in the axial direction (front-rear direction) occupied by the motor 5 in the housing 2 is M, the portion occupied by the forward / reverse selector switch 21 is L. The length of the portion of the switching operation lever 20 of the forward / reverse selector switch 21 exposed from the housing 2 to the outside is L1. In this embodiment, L and L1 are arranged so as to overlap with M in the axial direction. In particular, it is particularly preferable to arrange the forward / reverse changeover switch 21 so that L1 is within the range of M for improving operability. Further, in the housing 2, an axial length portion occupied by a portion protruding to the outside of the switch lever 10 (that is, the pressing surface 10 a) is S <b> 1. The switch lever 10 is disposed so that S1 is completely within the range of M.

  A permanent magnet 30 for position detection is provided at the rear end of the rotating shaft 5 d of the motor 5, and three Hall elements 31 are provided at positions facing the permanent magnet 30. The hall elements 31 are arranged on the substrate 32 at predetermined intervals in the circumferential direction, for example, at an angle of 60 °, in order to detect the rotational position of the rotor 5a.

  In the configuration of the present embodiment, first, when the holding portion of the housing 2 is grasped and swung together with the switch lever 10, the Hall element 14 detects the proximity and separation of the magnet, and the rectified direct current is supplied from the power supply circuit 18 to the inverter circuit. Is done. By the inverter circuit, a predetermined drive current is sequentially supplied to a predetermined coil 5c of the motor 5, whereby the rotor 5a rotates. When the motor 5 rotates, the rotational force is transmitted from the rotating shaft 5d to the speed reduction mechanism 50, decelerated to a predetermined rotational speed, the rotational force is transmitted to the shaft 7 and the socket 8 via the clutch mechanism 70, and the tip tool is moved. Rotate. Thereby, a screw or the like (not shown) that is a fastening member is fastened to the material to be fastened. When the screw is tightened and the tightening torque reaches a predetermined torque, the clutch mechanism 70 is operated and the connection between the speed reduction mechanism 50 and the shaft 7 is released, whereby the tightening of the tightening member is completed.

  When the clutch mechanism 70 is operated and power transmission is interrupted, the stop switch 75 is turned off to stop the motor 5. The stop switch 75 includes a permanent magnet 75a attached to a part of the clutch sleeve 74 of the clutch mechanism 70, and a hall element 75b provided at a position facing the permanent magnet 75a. The size of the permanent magnet 75a only needs to be large enough to influence the magnetic field on the Hall element 75b, and may be approximately the same as or slightly larger than the Hall element 75b. Further, an annular magnet may be attached to the outer peripheral side of the clutch sleeve 74 for ease of manufacturing.

  When the clutch mechanism 70 is not operated, that is, when the ball 71 is in the initial position and the ball 71 does not push the collar 72 forward, the clutch sleeve 74 is in the rearmost position, and the permanent magnet 75a and the hole The distance between the elements 75b is in the minimum state. Therefore, the output of the Hall element 75b becomes high. On the other hand, when the clutch mechanism 70 is operated and the collar 72 is pushed forward by the ball 71, the forward movement of the collar 72 in the axial direction is transmitted to the clutch sleeve 74 via the needle 73, and the spring 77 is The clutch sleeve 74 moves forward while compressing. At this time, the permanent magnet 75a attached to the clutch sleeve 74 moves in the direction away from the hall element 75b (forward direction), so that the output of the hall element 75b is switched to low. The control unit stops the rotation of the motor 5 by detecting the output change of the hall element 75b by a control unit described later.

  When tightening a fastening material such as a screw, the rotation of the motor 5 is set to the normal rotation direction. On the other hand, when loosening the screw, the rotation of the motor 5 can be reversed to reversely rotate the socket 8. This operation is performed by operating the switching operation lever 20 of the forward / reverse selector switch 21.

  FIG. 2 is a side view of the electric driver according to the embodiment of the present invention. The electric driver 1 of the present embodiment is provided with a hook 33 for suspension at the rear, and is suspended with elastic rubber or the like using the hook 33 in a line for factory flow work or the like. The worker works by holding the grip portion near the center of the housing 2 with one hand 24 (usually the dominant hand). At this time, the switch lever 10 can simultaneously perform an operation of grasping the electric driver 1 and an operation of turning on the switch, for example, by grasping with the index finger. On the other hand, the switching operation lever 20 is disposed at a position extending so as to protrude forward in parallel with the longitudinal direction of the cylindrical housing 2. In addition, the switch lever 10 is attached to the upper side, whereas the switching operation lever 20 is attached to the lower side which is the opposite side separated by 180 degrees in the rotation direction. Thus, by arranging the switch lever 10 and the switching operation lever 20 at symmetrical positions with respect to the rotating shaft 5 d of the motor 5, the operator releases the index finger to release the switch lever 10 and releases the hand 24 from the housing 2. It is possible to operate the switching operation lever 20 simply by moving the thumb portion without moving.

  A tip tool 36 is attached to the front side of the socket 8. The tip tool 36 can be attached to and detached from the socket 8. In the present embodiment, the tip tool 36 is an example of a plus driver. However, the present invention is not limited to this, and any other tip tool such as a minus driver, a drill, or a grindstone can be mounted.

  FIG. 3 is a bottom view of the electric driver 1. In this figure, since it is a figure for demonstrating the positional relationship of the external shape of the housing 2, and the switching operation lever 20, detailed illustrations, such as the display part 23, are abbreviate | omitted. The housing 2 is formed with a grip portion 2c in which the diameter of the housing 2 is the smallest for an operator to grip with one hand. Since the motor 5 is disposed inside the grip portion 2c, the heavy motor 5 is in the grip position, so that the weight balance is good and the usability is good. The rear side of the grip portion 2c is configured such that the tail portion 2d of the housing 2 becomes wider in the left-right direction in order to mount the three circuit boards of the power supply board 26, the inverter board 27, and the control board 28. The forward / reverse selector switch 21 is accommodated in a portion (switch accommodating portion 2e) protruding rearward and forward from the tail portion 2d. It will be understood from FIG. 3 that the switching operation lever 20 is a parallel plate-like lever.

  FIG. 4 is a cross-sectional view taken along the line AA in FIG. In the AA part of FIG. 2, the diameter of the housing 2 is the thinnest because it is a part that the operator holds with one hand. A switch lever 10 is provided on the upper side of the housing 2 on the rear side of the AA portion. The outer shape of the tail portion 2d of the housing 2 is substantially rectangular, and is formed so that the width in the left-right direction (lateral direction) is particularly wide. The movement direction of the switch lever 10 is that when the switch lever 10 is moved in the direction of the arrow 38, the rotation of the motor 5 is turned on. When the switch lever 10 is released, the switch lever 10 is actuated by the action of the spring 11 (see FIG. 1). Moves in the opposite direction to the arrow 38 to return to the original position, and the rotation of the motor 5 is turned off. A forward / reverse selector switch 21 is provided below the housing 2 and outside the motor 5 in the radial direction, and a switching operation lever 20 projects forward from the forward / reverse selector switch 21. The switching lever 20 is a plate-like member that is long in the vertical direction. By swinging in the direction of the arrow 37a or 37b, the rotation direction of the motor 5 is the forward direction (tightening direction) and the reverse direction (relaxing direction). You can switch to

  FIG. 5 is a partial bottom view showing the operation of the switching operation lever 20 of FIG. The switching operation lever 20 can be swung in the direction of an arrow 39, has three stop positions, the position indicated by 20a is a neutral position (a position where the motor 5 does not rotate even when the switch lever 10 is gripped), and 20b. Is a position where the motor 5 is rotated forward (position where the tightening member is tightened), and 20c is a position where the motor 5 is reversely rotated (position where the tightening member is loosened).

  As described above, in this embodiment, the switching operation lever 20 of the forward / reverse selector switch 21 is disposed in the middle part of the housing 2, that is, the position where the motor 5 is housed or overlapped with the grip 2c, Since the switching operation lever 20 is arranged at a symmetrical position with respect to the rotating shaft 5d of the motor 5, the protruding direction of the switching operation lever 20 is substantially parallel to the direction of the rotating shaft 5d. It becomes easy to operate the changeover switch 21. In addition, since the distance between the grip portion 2c and the switching operation lever 20 can be shortened, forward / reverse switching can be easily performed by simply moving the thumb while holding the main body.

  Next, the configuration and operation of the drive control system of the motor 5 will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of the drive control system of the motor 5. In this embodiment, the motor 5 is constituted by a three-phase brushless DC motor. This brushless DC motor is a so-called inner rotor type, and includes a rotor (rotor) 5a including a plurality of sets (two sets in this embodiment) of permanent magnets (magnets) including N poles and S poles. And a stator (stator) 5b composed of star-connected three-phase stator windings U, V, and W. When the switch operation detection circuit 90 detects that the signal from the hall element 14 for the start switch has become high, the calculation unit 81 is based on the position detection signal from the hall element 31 and the stator windings U, V, The energization direction and time for W are controlled, and the motor 5 is rotated at a predetermined rotational speed.

  The electronic element mounted on the inverter board 27 is an inverter circuit 82 composed of six switching elements 16 (Q1 to Q6) such as FETs connected in a three-phase bridge format. The gates of the six switching elements Q1 to Q6 that are bridge-connected are connected to the control signal output circuit 83 mounted on the control board 28, and the drains or sources of the six switching elements Q1 to Q6 are the star Connected to the connected stator windings U, V, W. As a result, the six switching elements Q1 to Q6 perform a switching operation by the switching element drive signals (drive signals such as H4, H5, and H6) input from the control signal output circuit 83 and are applied to the inverter circuit 82. Electric power is supplied to the stator windings U, V, and W as three-phase (U-phase, V-phase, and W-phase) voltages Vu, Vv, and Vw using the direct current 18a that is output from the power supply circuit 18.

  Of the switching element drive signals (three-phase signals) for driving the gates of the six switching elements Q1 to Q6, the three negative power supply side switching elements Q4, Q5, Q6 are converted into pulse width modulation signals (PWM signals) H4, The power supply to the motor 5 is started based on the output signal of the Hall element 14 constituting the switch means of the motor 5 by the calculation unit 81 supplied as H5 and H6 and mounted on the control board 28.

  Here, the PWM signal is supplied to one of the positive power supply side switching elements Q1 to Q3 or the negative power supply side switching elements Q4 to Q6 of the inverter circuit 82, and the switching elements Q1 to Q3 or the switching elements Q4 to Q6 are switched at high speed. As a result, the power supplied from the direct current 18a to the stator windings U, V, W is controlled. In this embodiment, since the PWM signal is supplied to the negative power supply side switching elements Q4 to Q6, the power supplied to each stator winding U, V, W is adjusted by controlling the pulse width of the PWM signal. Thus, the rotational speed of the motor 5 can be controlled.

  The output of the forward / reverse selector switch 21 for switching the rotational direction of the motor 5 is input to the rotational direction setting circuit 92. The rotational direction setting circuit 92 changes the rotational direction of the motor each time a change in the forward / reverse selector switch 21 is detected. The control signal is switched to be transmitted to the calculation unit 81. Although not shown, the calculation unit 81 is a central processing unit (CPU) for outputting a drive signal based on the processing program and data, a ROM for storing the processing program and control data, and for temporarily storing data. RAM, a timer, and the like.

  The calculation unit 81 forms a drive signal for alternately switching predetermined switching elements Q1 to Q6 based on output signals of the rotation direction setting circuit 92 and the rotor position detection circuit 84, and outputs the drive signal as a control signal. Output to the circuit 83. As a result, the predetermined windings of the stator windings U, V, and W are alternately energized to rotate the rotor 5a in the set rotation direction. The current value supplied to the motor 5 is measured by the current detection circuit 89, and the value is fed back to the calculation unit 81 to be adjusted to the set driving power. The PWM signal may be applied to the positive power supply side switching elements Q1 to Q3.

  The control unit 80 is connected to a hall element 75b whose output signal is low when the clutch mechanism 70 is operated, and detects a change in the output of the hall element 75b. A signal for instructing the motor 5 to stop rotating. The clutch operation detection circuit 91 starts the tightening operation simply by pressing the switch lever 10 by the operator. When the tightening is completed to a predetermined torque, the clutch mechanism 70 is automatically operated and the rotation of the motor 5 is automatically stopped. To do. Thereafter, the operator releases the switch lever 10 to complete the operation.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a partial bottom view of the electric driver according to the second embodiment of the present invention. In the second embodiment, the lever of the forward / reverse selector switch 21 is not a rocking type but a sliding type switching operation lever 41. The rotation of the motor 5 can be switched between forward rotation and reverse rotation by moving the switching operation lever 41 in the direction of the arrow 42 from the position in the figure.

  FIG. 8 is a cross-sectional view taken along the line BB in FIG. 7 and a view seen from the back of the BB part. A switch lever 10 is provided on the upper side of the housing 2 on the rear side of the BB portion. The configuration in which the rotation of the motor 5 is turned on when the switch lever 10 is moved in the direction of the arrow 38 is the same as in the first embodiment. In the second embodiment, the switching operation lever 41 of the forward / reverse selector switch 40 provided below the housing 2 is not a swing type but a parallel movement type. The switching operation lever 41 can be slid from the position shown to the position of the arrow 42a or 42b.

  9 and 10 are diagrams for explaining a third embodiment of the present invention. FIG. 9 is a partial bottom view of the electric driver according to the second embodiment of the present invention. In the third embodiment, push-type push buttons 45 a and 45 b are provided as the forward / reverse selector switch 45. The pressing direction of the push buttons 45 a and 45 b is parallel to the longitudinal direction of the cylindrical housing 2. When neither of the push buttons 45a and 45b is pushed, it is a neutral position (a position where the motor 5 does not rotate even when the switch lever 10 is gripped), and when only the push button 45a is pushed in the direction of the arrow 46a, the motor 5 Is rotated forward (tightening member is tightened). On the other hand, when only the push button 45b is pressed in the direction of the arrow 46b, the motor 5 is rotated in the reverse direction (the tightening member is loosened). The push buttons 45a and 45b cannot be pressed at the same time, and by pressing the push buttons 45a and 45b that are not pressed halfway, both the pressed states are released to the neutral position.

  FIG. 10 is a cross-sectional view taken along the line CC in FIG. 9 and a view seen behind the line CC. A switch lever 10 is provided on the upper side of the housing 2 on the rear side of the CC section. The configuration in which the rotation of the motor 5 is turned on when the switch lever 10 is moved in the direction of the arrow 38 is the same as in the first embodiment. In the third embodiment, the forward / reverse selector switch 47 provided below the housing 2 has circular push buttons 45a and 45b. As described above, in the third embodiment, the push buttons 45a and 45b are provided in the operation unit for forward / reverse switching, and the forward rotation and the reverse rotation are switched by pressing the push buttons 45a and 45b. The operator can operate the push buttons 45a and 45b only by moving the thumb portion without releasing the hand from the housing 2.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the above-mentioned Example, A various change is possible within the range which does not deviate from the meaning. For example, in the above-described embodiment, the electric driver has been described as an example of the electric tool. However, the present invention is not limited to this, and other portable rotary tools such as an electric saw and an electric hammer can be similarly applied. Further, in the present embodiment, an example of an electric rotary tool driven by a commercial power source has been described. However, the present invention can be similarly applied to a cordless electric tool using a battery pack.

DESCRIPTION OF SYMBOLS 1 Electric driver 2 Housing 2a, 2b Fixing rib 2c Gripping part 2d Tail part 2d Gripping part 2e Switch accommodating part 3 Case 4 Dial 5 Motor 5a Rotor 5b Stator 5c Coil 5d Rotating shaft 6 Cooling fan 7 Shaft 8 Socket 9 Gear Box 10 Switch lever 10a Press surface 10b End 11 Spring 12 Rotating shaft 13 Permanent magnet 14 Hall element 15 Substrate 16 Switching element 17 Control circuit 18 Power supply circuit 19a, 19b Bearing 20 Switching operation lever 21 Forward / reverse switch 22 Dial 23 Display Part 24 (operator's) hand 25a Axis line 25b Center line 26 Power supply board 27 Inverter board 28 Control board 29a Power cord 29b Connector 30 Permanent magnet 31 Hall element 32 Board 33 Hook 36 Tip tool 40 Forward / reverse Switch 41 Switch operation lever 45 Forward / reverse switch 45a, 45b Button 47 Forward / reverse switch 50 Reduction mechanism 70 Clutch mechanism 71 Ball 72 Collar 73 Needle 74 Clutch sleeve 75 Stop switch 75a Permanent magnet 75b Hall element 77 Spring 80 Controller 81 Arithmetic unit 82 Inverter circuit 82 Rotation direction setting circuit 83 Control signal output circuit 84 Rotor position detection circuit 89 Current detection circuit 90 Switch operation detection circuit 91 Clutch operation detection circuit 92 Rotation direction setting circuit

Claims (12)

A cylindrical housing having a gripping portion ;
A motor disposed inside the gripper;
A power tool having a tip tool holding portion protruding from the front end of the housing,
A forward / reverse changeover switch for switching the rotation direction of the motor, housed in a protruding portion of the housing, which is located on the rear side of the gripping portion and protrudes radially outward from the gripping portion;
An electric tool characterized in that a switching operation part of the forward / reverse selector switch is provided to be exposed to the grip part side from the protruding part . Provide a start switch for rotating the motor,
The electric tool according to claim 1, wherein the switching operation portion of the forward / reverse selector switch and the switch lever of the start switch are arranged at symmetrical positions with respect to the rotation axis of the motor. The electric power tool according to claim 2, wherein the switching operation unit protrudes outside from the housing and is provided at a position overlapping the motor in the axial direction.   4. The electric tool according to claim 2, wherein the switch lever is provided at a position that protrudes outward from the housing and overlaps the motor in the axial direction.   The electric tool according to any one of claims 1 to 4, wherein the forward / reverse selector switch is operated in a direction perpendicular to a longitudinal direction of the cylindrical housing. The electric tool according to claim 5, wherein the forward / reverse selector switch swings the switching operation unit to switch between forward rotation and reverse rotation. The electric tool according to claim 5, wherein the forward / reverse selector switch switches between forward rotation and reverse rotation by sliding the switching operation unit .   The electric tool according to any one of claims 1 to 4, wherein the forward / reverse selector switch is operated in a direction parallel to a longitudinal direction of the cylindrical housing.   The electric tool according to claim 8, wherein a push button is provided on the forward / reverse selector switch, and the forward rotation and the reverse rotation are switched by pressing the push button. A motor,
A housing that accommodates the motor and extends in the front-rear direction, and can grip the outer periphery;
A power tool having a tip tool holding portion protruding from a front portion of the housing,
The housing includes a gripping portion that can accommodate and grip the motor, and a protruding portion that is located on the rear side of the gripping portion and protrudes radially outward from the gripping portion,
An electric tool characterized in that a switch having an operation part exposed to the grip part side from the protruding part is provided in the protruding part . The housing has a tail portion having a diameter larger than that of the gripping portion behind the gripped portion,
The power tool according to claim 10, wherein the operation portion protrudes forward from the tail portion.   The power tool according to claim 10, wherein the operation unit is operable in a direction intersecting with the front-rear direction.

Images