JP4662309B2 - Driving machine - Google Patents

Description

  The present invention relates to a driving machine that uses a motor as a driving source for hitting fasteners such as nails and staples, and in particular, a drive having a driver blade that hits the fastener with the rotational driving force of the motor in the electric driving machine. The present invention relates to a controller that controls the operation timing of a power transmission mechanism including a clutch mechanism that transmits a linear driving force to a child.

  A compressed air type using an air compressor is most frequently used as a driving method for a conventional general fastener driving machine. For this reason, for example, when transporting from the first floor to the second floor of a work site such as a building building and using the driving machine, it is necessary to carry the air compressor together with the driving machine, which is very inconvenient to move. In addition, since there are few flat places in the work site where building materials and tools are brought in, it may be difficult to secure a place for the air compressor, a drive power source, and the like. Therefore, as disclosed in Patent Document 1 below, an electric driving machine has been proposed that changes the kinetic energy of a flywheel that is rotationally driven by a motor to linear kinetic energy that drives a fastener such as a nail or staple. ing. In this electric driving machine, a flywheel is rotated by a motor, and the rotational energy is transmitted to a nail driving mechanism by a power transmission mechanism such as a clutch to perform a nail driving operation.

JP-A-8-205573

  However, in the electric driving machine using the rotational kinetic energy of the conventional flywheel as described above, a speed sensor and a sensor circuit for detecting the rotational speed of the flywheel together with a controller for controlling the rotational speed of the motor. It is necessary to provide. For this reason, the mechanical structure of the flywheel and the speed sensor is complicated, and it is necessary to consider the positional relationship between the speed sensor circuit and the speed controller of the motor, making it difficult to reduce the size and cost of the controller. .

  An object of the present invention is to provide an electric driving machine that omits a rotational speed sensor, detects a counter electromotive force of a motor with a controller including a rotational speed control of the motor, and controls a power transmission unit (clutch mechanism). It is in.

  Among the inventions disclosed in accordance with the present invention in order to solve the above problems, the summary of typical ones will be described as follows.

One feature of the present invention is a housing having a fastener striking portion at one end, a magazine installed in the fastener striking portion of the housing, and supplying the fastener to the fastener striking portion, and in the housing A driver that is installed and performs a linear motion so as to strike the fastener supplied to the fastener striking portion, a motor installed in the housing, and a rotational motion of the motor that is mechanically coupled to the motor. A flywheel capable of accumulating kinetic energy based on the above and a driving element feed that gives the driving element a rotational driving force as a linear driving force to the driving element so as to strike the driving element on the fastener of the fastener hitting part The flywheel and the drive element feed mechanism are engaged so that the mechanism and the rotational drive force of the flywheel are transmitted to or blocked from the drive element feed mechanism. Alternatively, a power transmission unit operable in a disengaged state, an engagement / disengagement unit for controlling the power transmission unit to the engagement state or the disengagement state, and a controller for controlling the rotational movement of the motor and the engagement / disengagement unit The controller includes a switching element for turning on or off power supply to the motor, motor control means for outputting a control signal for turning on or off the switching element, and the motor control. the power supply to the motor for a predetermined time off by means, and a voltage detecting means for detecting the voltage across the motor at the time of the oFF, a first voltage V1 across it detects by the voltage detecting means, a predetermined Based on the second both-end voltage V2 detected after time, the time until the rotational speed of the motor reaches a predetermined rotational speed is determined, It turns on the power supply of between the motor of the constant time is to have so as to control the engaged state the engagement disengagement means after lapse of the ON time.

Another feature of the present invention includes a the voltage across the motor, wherein the controller is detected, the storage unit in which the motor is to store information representing the relationship between the on time to reach the predetermined rotational speed, the information The on-time is determined by referring to FIG.

Another feature of the present invention, said controller is said first voltage across V1, in that so as to obtain the on-time by using a programmed arithmetic expression from the second voltage across V2.

Another feature of the present invention, the engagement disengagement means includes a solenoid, the power transmission portion by the driving of the solenoid is configured to operate in the engaged state or the disengaged state, the controller, the on-time When the time elapses, the motor is stopped and the solenoid is driven.

Another feature of the present invention is that the controller engages with the disengagement means when the ON time determined based on the both-end voltages V1, V2 of the motor detected by the voltage detection means is a predetermined value or more. The command is not output.

  According to the present invention, since the motor counter electromotive force detection mechanism is incorporated in the controller for controlling the rotational speed of the motor, a special rotation sensor for detecting whether the rotational speed of the flywheel has reached a predetermined value is attached to the flywheel. There is no need. In addition, since it is not necessary to calculate the time until a fastener such as a nail, staple, or screw is driven by a microcomputer using a complicated arithmetic expression, the processing speed can be increased. Therefore, it is possible to reduce the size and cost of the controller.

  The above and other objects, and the above and other features and advantages of the present invention will become more apparent from the following description of the present specification and the accompanying drawings.

  Hereinafter, an embodiment in which the fastener driving machine of the present invention is applied to an electric nail driving machine will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

  First, the overall configuration of an electric nail driver according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8.

  As shown in the top view of FIG. 1 and the side view of FIG. 2, the driving machine 100 includes a main body housing portion 1a having a nail striking portion 1c at a front end portion, and a nail striking portion 1c (front end portion) of the main body housing portion 1a. The magazine 2 for continuously supplying the nail to the nail striking portion 1c, the handle housing portion 1b extending from the main body housing portion 1a, and the branch portion of the handle housing portion 1b are provided. It includes a trigger switch 5 for operating when nailing, and a battery pack (DC power supply unit) 7 including a storage battery such as a lithium ion battery connected to the lower end of the handle housing portion 1b.

  Although not shown, the magazine 2 is filled with a large number of connecting nails (blocks), and the connecting nails are sequentially supplied with nails 2a that are hit by the injection port 1d of the nail striking portion 1c. As described above, the magazine 2 is biased by a spring (not shown) from below.

  In the main body housing portion 1a, there is provided a driving element 3 for applying a striking force to the nail 2a in the nail striking portion 1c. The driver 3 includes a driver blade 3a that transmits a striking force to the head of the nail 2a, and a rack 3b that meshes with the pinion 11 that rotates. The rack 3b of the driving element 3 and the pinion 11 meshing with the rack 3b constitute a driving element feeding mechanism 3c that applies the rotational driving force of the pinion 11 to the driving element 3 as a linear driving force.

  On the other hand, as shown in FIG. 4, a motor (DC commutator motor) 6 that is driven by a DC power source by a battery pack 7 (see FIG. 2) and serves as a power source for driving a nail is disposed in the main body housing portion 1 a. The motor gear 8 fixed to the rotating shaft of the motor 6, the flywheel 9 meshed with the motor gear 8, the drive rotating shaft 10 that rotatably supports the flywheel 9, and the follower that rotatably supports the pinion 11. The rotary shaft 12, the coil spring 13 including the end portion of the drive rotary shaft 10 and the driven rotary shaft 12 provided on the same axis, and the solenoid drive portion (shaft) 15 are driven in the rotational axis direction of the pinion 11. A solenoid 14 is installed. As shown in the side view (a) and the front view (b) of FIG. 3, the coil spring 13 has a spiral shape wound at a predetermined pitch in the axial direction. As shown in FIG. 4, one end 13 a of the coil spring 13 is fixed to the drive rotary shaft 10 of the flywheel 9, and the right edge end of the coil spring 13 encloses the outer peripheral surface of the drive rotary shaft 10. It is mechanically connected to the drive rotary shaft 10. That is, when the drive rotating shaft 10 rotates, the coil spring 13 is connected to rotate.

  Further, as shown in FIG. 4, an urging member 16 having an inclined groove portion 16a and a solenoid return spring 17 are disposed at the end of the solenoid driving portion 15, and the urging member 16 and the solenoid return spring 17 are cylindrical. The power transmission mechanism is reduced in size by being installed on the inner peripheral surface side of the shaped driven rotating shaft 12.

  Further, as shown in FIGS. 4 and 5, a hole 18 is provided in a part of the cylindrical driven rotary shaft 12, and a ball (steel ball) 19 serving as a spring contact member for the coil spring 13 is provided in the hole 18. Is installed to be movable in the radial direction. The ball 19 is supported from the inner peripheral surface side of the driven rotary shaft 12 by the inclined groove portion 16 a of the biasing member 16, and a driven rotary shaft support portion that rotatably supports the driven rotary shaft 12 in the outer peripheral direction of the ball 19. 20 is installed, and the movement amount of the ball 19 in the outer peripheral direction is limited so that the ball 19 is always caught in the rotation direction of the driven rotation shaft 12 of the hole 18 of the driven rotation shaft 12. The other end 13 b of the coil spring 13 is installed between the ball 19 and the driven rotary shaft support 20.

  As shown in FIG. 5, the inner diameter of the coil spring 13 in the natural state is larger than the driven rotating shaft 12 and smaller than the driving rotating shaft 10. Therefore, in the natural state, the coil spring 13 is not in contact with the driven rotary shaft 12 and is in contact with the drive rotary shaft 10, and the coil spring 13 rotates in synchronization with the rotation of the drive rotary shaft 10. The shaft 12 does not rotate.

  As shown in FIGS. 6 and 7, if an on-current flows through the solenoid 14, the solenoid drive unit 15 and the biasing member 16 move toward the flywheel 9, so that the ball 19 tilts the biasing member 16. It is pushed into the hole 18 along the groove 16 a and protrudes from the outer peripheral surface of the driven rotary shaft 12 to press the other end 13 b of the coil spring 13 against the driven rotary shaft support 20. As a result, the rotating flywheel 9 fastens the coil spring 13 to the outer peripheral surface of the driven rotating shaft 12, so that the coil spring 13 that is in contact with (connected to) the driving rotating shaft 10 is attached to the spring seat 12 a of the driven rotating shaft 12. Becomes a contact state, and the driven rotary shaft 12 is rotated in synchronization with the rotation of the drive rotary shaft 10. That is, when a current is supplied to the solenoid 14, the rotational force of the flywheel 9 is transmitted to the pinion 11 constituting the driver feed mechanism 3 c via the coil spring 13. If the pinion 11 rotates, it is converted into a linear motion by the rack 3b meshing with the pinion 11, and the driver blade 3a fixed to the driver 3 strikes the head of 2a. As will be described later, after the driver blade 3a hits the nail 2a, the current flowing through the solenoid 14 is turned off, so that the coil spring 13 has a mechanical contact (coupling) with the spring seat 12a of the driven rotary shaft 12. Open. A driver return spring 4 (see FIG. 2), which is a constant load spring, for example, is connected to the end of the driver 3. With this spring force, the position of the driving element feed mechanism 3c (rack 3b and pinion 11) after the impact is returned to the position before the impact.

  As is clear from the above configuration, the spring seat 12a and the coil spring 13 of the driven rotary shaft 12 are capable of operating between the flywheel 9 and the driver feed mechanism 3c in an engaged state or a disengaged state. The solenoid 14, the urging member 16, and the ball 19 function as an engagement / disengagement unit that controls the power transmission unit to an engaged state or a disengaged state. Therefore, the power transmission unit can transmit the rotational energy of the flywheel 9 to the drive element feed mechanism 3c, and the engagement / disengagement unit can put the power transmission unit into an engaged state or a detached state.

  A push lever switch 22 is provided at the tip of the nail striking portion 1c of the main body housing portion 1a. The push lever switch 22 has a function of adjusting the nail driving depth to the workpiece and adjusting the nail driving timing together with the trigger switch 5.

  Further, a controller (control circuit device) 50 for controlling the rotation of the motor 6 and the drive time (ON time) of the solenoid 14 based on the operation of the push lever switch 22 and the trigger switch 5 is provided in the main body housing portion 1a. (See FIG. 2).

  Next, details of the controller 50 will be described with reference to FIGS. 9 and 10.

  As shown in FIG. 9, the controller 50 includes a push lever switch detection circuit 52 that receives a signal from the push lever switch 22, a trigger switch detection circuit 53 that receives a signal from the trigger switch 5, and power supply to the motor 6. And a motor back electromotive voltage detection circuit 56 for detecting a back electromotive voltage due to the rotation of the motor 6 when the motor is turned from the on state to the off state, and further includes a push lever switch detection circuit 52 and a trigger switch detection circuit. 53 and a microcomputer for controlling the motor drive circuit 54 of the motor 6 and the solenoid drive circuit 55 of the solenoid 14 based on the output signals of the motor 53 and the motor back electromotive voltage detection circuit 56 (hereinafter simply referred to as “microcomputer”). ) 51.

  The microcomputer 51 stores a control program such as drive control of the motor 6 and drive control of the solenoid 14, and also stores a table for determining an on-time of power supply to the motor from a detected back electromotive voltage of the motor, which will be described later. Read-only memory) 51b, a CPU (Central Processing Unit) 51a having a calculation unit that executes a control program stored in the ROM 51b, etc., storage of the work area of the CPU 51a, and input from the motor back electromotive voltage detection circuit 56 A random access memory (RAM) 51c for temporarily storing data relating to the counter electromotive voltage and a TIM (timer) 51d including a reference clock signal generator.

  The microcomputer 51 sends a motor drive circuit 54 for controlling the base current of the switching element (for example, PNP transistor) 57 for applying the voltage of the battery pack 7 to the motor (specifically, the armature coil) 6 (see FIG. A motor drive signal (control signal) as shown in a) is supplied, and a solenoid drive circuit 55 as shown in FIG. 10D is supplied to the solenoid drive circuit 55 to control the drive time (on time) of the solenoid 14. A signal (control signal) is supplied. The motor drive circuit 54 drives a switching element (for example, a PNP transistor) 57 for turning on or off the drive current of the motor 6 to be turned on or off. The solenoid drive circuit 55 drives a switching element (for example, a PNP transistor) 58 on or off in order to turn on or off the drive current of the solenoid 14.

  A motor back electromotive voltage detection circuit 56 is installed in order to detect the voltage (back electromotive voltage) at both ends of the rotation of the motor 6, and a signal corresponding to the motor back electromotive voltage is sent from the motor back electromotive voltage detection circuit 56 to the microcomputer 51. Sent. As shown in FIG. 10 (a), the voltage detected by the counter electromotive force of the motor 6 is obtained by supplying power to the motor 6 during a short time Toff, for example, 5 ms (milliseconds). As shown in FIG. 10C, the motor voltages V1 and V2 according to the number of rotations of the motor 6 at the time of off are detected.

  The equivalent circuit of the DC motor 6 includes a coil electromotive force (counter electromotive force) determined by a coil inductance and a coil winding resistance, a voltage drop in the brush portion, a motor field, the number of all armature conductors, and a rotational speed. Of these, the core inductance, winding resistance, and voltage drop in the brush portion vary depending on the motor current. However, during the Toff period when the switching element 57 is off, it may be considered that the motor speed electromotive force itself is output as the motor voltage (V1, V2), and the speed electromotive force is proportional to the rotational speed of the motor 6. Therefore, by determining the predetermined counter electromotive voltage (Vd) of the motor 6, the motor rotation speed as shown in FIG. 10B, that is, the predetermined rotation speed (Nd) of the mechanically coupled flywheel 9 is obtained. ) Note that the motor rotation speed shown in FIG. 10B is a result of experimental measurement in advance in order to grasp the relationship with the motor voltage shown in FIG.

  According to the present invention, the on / off control and the motor back electromotive force detection are performed once or more, preferably twice or more during the acceleration of the motor 6, and the motor voltages (back electromotive voltages) V1 and V2 detected in advance are detected in advance. The acceleration time Tc until the counter electromotive voltage of the motor 6 reaches a predetermined voltage Vd corresponding to the predetermined rotational speed Nd giving appropriate rotational energy is calculated by an arithmetic expression or table prepared based on the actual measurement ((a of FIG. 10 ))), And after the predicted acceleration time Tc has elapsed, the motor 6 is turned off and the solenoid 14 is driven.

  As a result, it is not necessary to attach a conventional rotation sensor to the flywheel, and the product can be reduced in size and cost. In addition, since it is not necessary to frequently turn off the motor 6, the rotation start-up time of the motor 6, that is, the acceleration time of the motor 6 can be increased. In addition, since it is not necessary to periodically turn off the motor 6 in order to see the rotation speed, the voltage of the battery pack 7 can be applied to the motor 6 without interruption and the motor 6 can be rotated effectively. Can be used.

  Next, the operation of the controller 50 will be described in more detail with reference to the flowchart of the control procedure shown in FIG.

  The microcomputer 51 performs the initial setting in step S101, and then in step S102, when the operator presses the front end of the main body of the driving machine 100 against a not-shown driving member (working member), the push lever switch 22 is turned on. Since it is turned on, the on state is detected. Thereafter, when the operator further pulls the trigger switch 5 in step S103, the trigger switch 5 is turned on, and the on state is detected. When the push lever switch 22 is first turned on and then the trigger switch 5 is turned on, both the push lever switch 22 and the trigger switch 5 are turned on, so that it is determined as YES in step S103.

  If it is determined as YES in step S103, the process proceeds to step 104 where the microcomputer 51 issues a motor drive signal (control signal) to the motor drive circuit 54 and strikes the nail (fastener) 2a with the driver 3. Start the hitting operation. Time t0 in the time chart shown in FIG. 10 indicates when both the push lever switch 22 and the trigger switch 5 are turned on. When the motor drive circuit 54 receives a motor drive signal from the microcomputer 51 at time t0 as shown in FIG. 10A, the motor drive circuit 54 turns on the switching element 57 to start the motor 6.

  Next, in step S105, as shown in FIG. 10A, the time Ta from the start at time t0 to time t1 is set to 100 ms, for example, and the switching element 57 is kept on and the motor 6 is turned on. Drive. If it is determined in step 105 that the time Ta = 100 ms has elapsed (YES in step S105), the microcomputer 51 turns off the switching element 57 in step 106, and the time from time t1 to time t2 in step S107. The switching element 57 is turned off for Toff (for example, 5 ms).

  When the time Toff has elapsed in step S107 and time t2 has been reached (when YES is determined in step S107), the process proceeds to step S108, and the microcomputer 51 corresponds to the voltage across the motor from the motor back electromotive voltage detection circuit 56. The signal is detected and stored in the RAM 51c. As shown in FIG. 10C, this value is set as the first motor back electromotive voltage V1.

  Thereafter, in step S <b> 109, the microcomputer 51 turns on the switching element 57 via the motor drive circuit 54 to rotate the motor 6. The ON state of the switching element 57 is between time t2 and time t3 (for example, 50 ms) as shown in FIG. Whether or not time Tb = 50 ms has elapsed is determined in step S110.

  If it is determined that the motor 6 is in the on state for the time Tb, the process proceeds to step S111, the switching element 57 is turned off, and the supply of power to the motor 6 is turned off.

  In step S112, the OFF state of power supply to the motor is set to time Toff = 5 ms from time t3 to time t4. In step S113 after this time Tb has elapsed, the microcomputer 51 detects the motor back electromotive voltage detection. A signal corresponding to the voltage across the motor from the circuit 56 is detected, and the voltage across the motor is stored in the RAM 51c of the microcomputer 51 as the second motor back electromotive voltage V2 (see (c) of FIG. 10).

  Next, the process proceeds to step S114, and the values of the first motor counter electromotive voltage V1 and the second motor counter electromotive voltage V2 (see FIG. 10C) stored in the RAM 51c are stored in advance in the ROM 51b of the microcomputer 51. Using the stored table as shown in FIG. 12, the power supply to the motor is turned on until a predetermined counter electromotive voltage (the counter electromotive voltage Vd when the rotational driving force of the motor reaches the maximum) is reached. Time Tc (see FIGS. 10A and 10C) is determined (predicted). In the present embodiment, by using the table shown in FIG. 12 stored in the ROM 51b of the microcomputer 51, the on-time Tc (from the actually measured back electromotive voltages V1 and V2 until the power supply to the motor 6 is turned off ( Time until reaching a predetermined counter electromotive voltage Vd) is determined.

  In the table shown in FIG. 12, the first motor counter electromotive voltage V1 shown on the vertical axis increases as it goes from V11 to V20, and the second motor counter electromotive voltage V2 shown on the horizontal axis goes from V21 to V30. It shows that the voltage becomes high. Further, the determination on-time Tc becomes shorter or constant as V1 and V2 become higher. When determining Tc using this table, for example, when the first counter electromotive voltage V1 is V14 or more and less than V15, the row of V14 is used, while the second counter electromotive voltage V2 is V25 or more and less than V26. If there is, use the column of V25. In this example, the value Tc45 is determined as the ON time Tc from the column V14 and the row V25. That is, if electric power is supplied to the motor 6 during the determination on-time Tc, the motor 6 generates a predetermined counter electromotive voltage Vd, and rotational energy necessary for driving the nail can be obtained.

  As described above, the motor back electromotive voltage corresponds to the number of rotations of the motor. In the above embodiment, the first back electromotive force is generated 100 ms after Ta starts to supply power to the motor 6 at time t0. The voltage V1 is measured, and after 50 ms (Tb), the second counter electromotive voltage V2 is measured and measured twice in total. From the result, the flywheel 9 is necessary for driving a nail. The time Tc until the rotational energy is stored is predicted.

  The relational expression with the on-time Tc from the actually measured value (V1, V2, etc.) of the counter electromotive voltage to the predetermined counter electromotive voltage Vd is expressed by the resistance of the field coil of the motor (Rmot) and the number of turns (N) And the values of the battery voltage (Vbat) and the internal resistance (Rbat) of the battery pack 7 are parameters. Therefore, as shown in FIG. 12, the relationship between V1 and V2 and Tc should be tabulated beforehand by actual measurement as shown in FIG. Is desirable. The numerical values in this table are obtained as follows, for example.

  The rotational start characteristics of the motor are experimentally measured in advance from batteries and motors in various states, and the number of revolutions after t2 hours and t4 hours described above from the start characteristics and the time to rise to a predetermined number of revolutions are determined. Ask. The number of revolutions after t2 hours and the number of revolutions after t4 hours can be converted into counter electromotive voltages, respectively, and rise to a predetermined rotational speed Nd (predetermined counter electromotive voltage Vd) determined from the converted counter electromotive voltages V1 and V2. The rising time is defined as a determination on time Tc.

  In the relationship table between the actually measured back electromotive voltages (V1, V2) and the determination on-time Tc shown in FIG. 12, a part of the Tc column can be blank as shown in FIG.

  In FIG. 13, as in FIG. 12, the first motor back electromotive voltage V1 shown on the vertical axis increases as it goes from V11 to V20, and the second motor back electromotive voltage V2 shown on the horizontal axis is from V21 to V30. The voltage increases as you go to. Further, the determination on-time Tc becomes shorter or constant as V1 and V2 become higher. As shown in the table of FIG. 13, since V1 <V2 is normally satisfied, a relational table for a value where V2 is smaller than V1 is unnecessary. In the table of FIG. 13, the blank part of the triangle in the lower left half represents a part that does not require a Tc value. For example, when the first motor back electromotive voltage V1 is V15 and the values V25 to V21 of the second motor back electromotive voltage V2 are values of V15 or less, the relationship value (Tc) between V15 and V25 to V21 is unnecessary. The line corresponding to V15 of Tc in the table is a space. At the same time, V1 << V2 (V2 that is much larger than V1) is also a value that is not normally possible due to the relationship between the power supply voltage of the motor 6 and the battery pack 7, and therefore the upper right triangle in the table of FIG. A relational value (Tc) is also unnecessary for the blank part.

  Furthermore, the numerical value of Tc in the table may be a combined numerical value for a certain range of the actual measured value of the second motor back electromotive voltage V2. For example, in the table of FIG. 13, the measured values V28 and V29 of the second motor back electromotive voltage V2 are the time Tc2 having the same determination on-time Tc with respect to the row of the actually measured value V15 of the first motor back electromotive voltage V1. However, practically, the same rotational energy can be obtained for the same time Tc2.

  In step S115, the ON time Tc determined in step S114 (Tc45 in the above example) is set (set) in the timer 51d as the timer time. As a result, the capacity of the ROM 51b of the microcomputer 51 that stores the table can be reduced without affecting the nailing operation, and the cost of the microcomputer can be reduced. Further, even in the case of an external ROM, the capacity can be reduced, and the cost of the ROM can be reduced.

  In further subsequent step S 116, the microcomputer 51 turns on the switching element 57 via the motor drive circuit 54. In step S117, the switching element 57 is turned on from time t4 to time te.

  If it is determined in step S117 that the Tc time has elapsed (YES in step S117), the process proceeds to step S118, and the microcomputer 51 controls the motor drive circuit 54 to turn off the switching element 57.

  Simultaneously with the off operation of the motor 6 in step S118, the process proceeds to step S119, and as shown in FIG. 10D, the microcomputer 51 sends a solenoid drive signal to the solenoid drive circuit 55 for a predetermined time Ts (for example, 20 ms). (Solenoid control signal) is output. During this time, the solenoid drive circuit 55 outputs a signal for turning on the switching element 58 to drive the solenoid 14 constituting the clutch mechanism. Thereby, the rotational driving force of the flywheel 9 is transmitted as a linear driving force to the driver 3 via the coil spring 13 constituting the clutch mechanism, and the driver blade 3a of the driver 3 strikes the nail 2a. Then, the nail 2a is driven into the workpiece. Whether or not the driving time Ts (20 ms) has elapsed is determined in step S120.

  If it is determined in step S120 that the predetermined time Ts after time te has elapsed as shown in FIG. 10D, the process proceeds to step S121, and the microcomputer 51 sends a solenoid drive signal (solenoid control) to the solenoid drive circuit 55. Signal), the switching element 58 is turned off, and the nail driving operation is terminated.

  When nailing is performed repeatedly, the process returns to step S102 again, and the push lever switch 22 is turned on when the push lever switch 22 is pressed against the driven member (member to be processed). The nail can be struck repeatedly by repeating S121.

  Next, the nailing operation of the entire driving machine 100 according to the embodiment of the present invention will be described with reference to FIGS.

  When the operator presses the push lever switch 22 against the workpiece and further pulls the trigger switch 5, the switching element 57 is turned on by the operation of the microcomputer 51 and the motor drive circuit 54 of the controller 50 as described above, and the battery pack The motor 6 rotates using 7 as a power source (see FIG. 9). As a result, the rotational driving force of the motor 6 is transmitted to the flywheel 9 via the motor gear 8 mechanically connected to the motor 6 and further rotates the coil spring 13 attached to the driving rotary shaft 10 (FIG. 4). reference). In this state, as the rotational speed of the motor 6 increases, the rotational speed of the flywheel 9 increases to a predetermined value with time (see FIG. 10). The flywheel 9 accumulates greater kinetic energy as the rotational speed increases as the motor 6 is driven. At this time, as shown in FIGS. 4 and 5, the inner diameter of the coil spring 13 is larger than the driven rotary shaft 12, so the rotational force of the coil spring 13 does not rotate the driven rotary shaft 12. Further, there is no problem of wear that occurs when the coil spring 13 and the driven rotary shaft 12 are in sliding contact.

The microcomputer 51 determines that the determined timer time Tc has elapsed from the counter electromotive voltage (V1, V2) of the motor 6 detected by the microcomputer 51 of the controller 50 (see FIG. 9) via the motor counter electromotive voltage detection circuit 56. If so, the microcomputer 51 turns on the switching element 58 via the solenoid drive circuit 55 to excite the solenoid 14. When the solenoid 14 is excited, as shown in FIGS. 6 and 7, the solenoid drive unit 15 and the urging member 16 move in the direction toward the flywheel 9, so that the ball 19 is moved by the inclined groove 16 a of the urging member 16. The driven rotary shaft 12 is pushed outward from the hole 18. As a result, since the coil spring 13 is sandwiched between the ball 19 and the driven rotary shaft support portion 20, the ball 19 and the coil spring 13 are mechanically connected by a frictional force. Furthermore, since the ball 19 and the driven rotary shaft 12 are always engaged, the coil spring 13 starts to wind around the driven rotary shaft 12 that has been stationary. As a result, a necessary and sufficient frictional force is generated between the coil spring 13 and the outer peripheral surface of the driven rotary shaft 12 by the winding force generated by using the rotational force of the drive rotary shaft 10, and the driven rotary shaft 12 is several tens of millimeters. A sufficient rotation speed can be obtained within seconds. At this time, since the contact portion of the ball 19 with the coil spring 13 is a curved surface, wear of the coil spring 13 is suppressed. Further, when the driven rotary shaft 12 rotates, the pinion 11 rotates in synchronization with each other, so that the driving element feed mechanism 3c in which the pinion 11 and the rack 3b mesh with each other is arranged so that the driving element 3 approaches the nail 2a filled in the magazine 2. The driving is finished when the driver blade 3a of the driver 3 completes a collision with the nail 2a. FIG. 8 shows a side view of the driving machine when the driving is completed.
When the driving is completed, the drive of the solenoid 14 is also finished, and the solenoid drive unit 15 and the urging member 16 are returned to the initial position by the spring force of the solenoid return spring 17. When the biasing member 16 returns to the initial position, the pressing force of the ball 19 disappears, so that the frictional force between the ball 19 and the coil spring 13 becomes so small that it can be ignored, and the inner diameter of the coil spring 13 increases until it reaches a natural state. . At this time, power transmission from the drive rotary shaft 10 to the driven rotary shaft 12 is cut off, so that the driver 3 (driver blade 3a), the pinion 11 and the rack 3b of the driver feed mechanism 3c, and the driver return spring 4 Returns to the initial state. The controller 50 can control the solenoid 14 constituting the disengagement means not to operate when the determined on-time Tc is equal to or greater than a predetermined value.

  According to the above embodiment, since it is not necessary to calculate the time until the nail is driven using a complicated arithmetic expression in the CPU without using a sensor for detecting the number of rotations, the processing speed is increased. The size and cost of the controller can be reduced.

  In the above embodiment, as shown in FIG. 9, the PNP transistor is provided as the switching element 57 between the positive terminal of the motor 6 and the positive terminal of the battery pack 7, but the output signal level of the motor driving circuit 54 or the motor In consideration of the input level of the back electromotive voltage detection circuit 56 and the like, an NPN transistor may be used as the switching element 57. In this case, a switching element 57 using a level shift circuit or an NPN transistor for the motor drive circuit 54 is connected between the − terminal of the motor 6 and the − terminal of the battery pack 7, and the motor back electromotive voltage detection unit 56. It is desirable to detect the voltage difference between the positive terminal of the motor 6 and the negative terminal of the motor 6.

  12 and FIG. 13, an approximate expression obtained experimentally or theoretically in advance for the relationship between V1 and V2 and Tc is obtained as a program in the microcomputer 51, and the measured V1 and V2 are measured. In each case, the calculation may be performed by the microcomputer 51 using the approximate expression. In this case, it is desirable to use a quadratic expression or a cubic expression as an approximate expression, omitting the use of an exponential function in consideration of the computing ability of the microcomputer 51. Further, Tc may be obtained as the counter electromotive voltage to be measured as one of V1 and V2.

  In the above-described embodiments according to the present invention, the case of a nail as a fastener for a driving machine has been described. However, the present invention can be applied to a fastener other than a nail such as a staple (a U-shaped nail) or a screw by a striking force. Even when applied to a driving machine for driving, the same effect as that of the nail driving machine described above can be obtained.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. is there.

The top view before nail driving | running | working of the driving machine which concerns on embodiment of this invention. The side view before nailing of the driving machine which concerns on embodiment of this invention. The side view (a) and front view (b) of the coil spring used for the driving machine which concerns on embodiment of this invention. The principal part enlarged top view before nail driving | running | working of the driving machine which concerns on embodiment of this invention. Sectional drawing which follows the breaking line AA shown in FIG. The principal part enlarged top view after nail driving | running | working of the driving machine which concerns on embodiment of this invention. Sectional drawing which follows the breaking line AA shown in FIG. The side view after nail driving | running | working of the driving machine which concerns on embodiment of this invention. The block diagram of the controller used for the driving machine which concerns on embodiment of this invention. 10 is a time chart showing the operation of the controller shown in FIG. 10 is a flowchart showing a control procedure of the controller shown in FIG. FIG. 10 is a first table example for predicting the relationship between the measured counter electromotive voltage of the motor used in the control procedure of the controller shown in FIG. 9 and the on-time for reaching the set counter electromotive voltage. 10 is a second table example for predicting the relationship between the measured back electromotive voltage of the motor used in the control procedure of the controller shown in FIG. 9 and the on time to reach the set back electromotive voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a: Main body housing part 1b: Handle housing part 1c: Nail striking part 1d: Injection port part 2: Magazine 2a: Nail (fastening) 3: Driver 3a: Driver blade 3b: Rack 3c: Driver feeding mechanism 4: Drive Child return spring 5: Trigger switch 6: Motor (commutator motor)
7: Battery pack 8: Motor gear 9: Flywheel 10: Drive rotation shaft 11: Pinion 12: Driven rotation shaft 12a: Spring seat 13: Coil spring 13a: One end of coil spring 13b: Other end 14 of coil spring: Solenoid 15: Solenoid driving part 16: Energizing member 16a: Inclined groove part 17: Solenoid return spring 18: Hole 19: Ball (steel ball) 20: Driven rotating shaft support part 22: Push lever switch 50: Controller (control circuit device)
51: Microcomputer 51a: CPU 51b: ROM 51c: RAM
51d: TIM (Timer) 52: Push lever switch detection circuit 53: Trigger switch detection circuit 54: Motor drive circuit 55: Solenoid drive circuit 56: Motor back electromotive voltage detection circuit 57: Switching element 58: Switching element 100: Driving machine

Claims (7)

A housing having a fastener hitting portion at one end;
A magazine installed in a fastener striking portion of the housing and for supplying the fastener to the fastener striking portion;
A driver installed in the housing and performing a linear motion so as to strike the fastener supplied to the fastener striking portion;
A motor installed in the housing;
A flywheel mechanically coupled to the motor and capable of storing kinetic energy based on the rotational motion of the motor;
A driving element feed mechanism that applies a rotational driving force of the flywheel as a linear driving force to the driving element so as to hit the driving element on the fixing element of the hitting part;
A power transmission unit operable to engage or disengage between the flywheel and the drive element feed mechanism so as to transmit or block the rotational driving force of the flywheel to the drive element feed mechanism; ,
Engagement / disengagement means for controlling the power transmission unit to the engagement state or the disengagement state;
A driving machine having a controller for controlling the rotational movement of the motor and the disengaging means;
The controller includes a switching element for turning on or off the power supply to the motor;
Motor control means for outputting a control signal for turning on or off the switching element;
The power supply of the motor control unit to the motor for a predetermined time off, and a voltage detecting means for detecting the voltage across the motor at the time of the OFF,
Based on the first both-end voltage V1 detected by the voltage detecting means and the second both-end voltage V2 detected after a predetermined time, an on-time until the rotational speed of the motor reaches the predetermined rotational speed is determined,
A driving machine which turns on the power supply of the motor for a determined time and controls the disengagement means to the engaged state after the on-time elapses. The controller includes a said end voltages V1, V2 of the detected motor, said motor having a storage unit for storing information representing a relation between on-time to reach the predetermined rotational speed, referring to the information The driving machine according to claim 1, wherein the ON time is determined by: The controller includes a first voltage across V1, driving machine according to claim 1, wherein using the programmed arithmetic expression from the second voltage V2 across and obtains the ON time. The engagement / disengagement means includes a solenoid, and is configured such that the power transmission unit operates in an engagement state or a disengagement state by driving the solenoid, and the controller turns off the motor when the on-time has elapsed. The driving machine according to any one of claims 1 to 3, wherein the driving is controlled so as to stop and drive the solenoid. The controller does not output an engagement command to the disengagement means when the ON time determined based on the both-end voltages V1, V2 of the motor detected by the voltage detection means is a predetermined value or more. The driving machine according to claim 1. A motor that rotates the flywheel;
A driving element feeding mechanism for converting the rotational driving force of the flywheel into a linear driving force and transmitting it to a driving element that strikes the fastener;
A power transmission unit for transmitting or interrupting the rotational driving force of the flywheel to the driver feed mechanism ;
In a driving machine comprising a controller for controlling on / off of electric power supplied to the motor,
When the power supply is turned off for a predetermined time after turning on the power supply of the motor for a certain time, the controller turns on the counter electromotive voltage generated by the rotation of the motor, and then turns on the power supply. Previously storing information representing the relationship with the time until the motor reaches a predetermined rotational speed,
After supplying power to the motor for a certain period of time , turning off the power supply from on , detecting the back electromotive force generated by the rotation of the motor,
Based on the detected counter electromotive voltage and the information stored in advance , obtain the on-time of the motor until the motor reaches a predetermined rotational speed,
Between said on-time, to supply power to the motor,
After a lapse of the on-time, driving machine, characterized in that with to turn off the supply of power to the motor, and disconnected state of the power transmission unit. A motor that rotates the flywheel;
A driving element feeding mechanism for converting the rotational driving force of the flywheel into a linear driving force and transmitting it to a driving element that strikes the fastener;
A power transmission unit for transmitting or interrupting the rotational driving force of the flywheel to the driver feed mechanism;
In a driving machine comprising a controller for controlling on / off of electric power supplied to the motor,
After supplying electric power to the motor for a certain period of time, the supply of electric power to the motor is changed from the on state to the off state, the first counter electromotive voltage is detected, and the electric power supply of the motor is turned on for a predetermined time from the detection. Then, the second counter electromotive voltage is detected by changing the power supply to the motor from the on state to the off state again, and the on time is determined based on the first and second counter electromotive voltages,
Power is supplied to the motor during the determined on-time, and after the on-time has elapsed, the power supply to the motor is turned off and the power transmission unit is turned off. To drive.

Images