JP2012139752A - Power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power tool that is capable of detecting operation condition, regardless of variations of rotating condition of a motor.SOLUTION: The power tool has a motor 21, a housing integrating the motor 21, a mounting section driven by the motor 21 and capable of mounting a boring bit 2 machining a member to be machined, and a controller for controlling the rotation of the motor 21, and further has an operating condition detecting means for detecting the rotational frequency of the motor 21, a reference value deriving means for deriving first to fourth reference values based on the detected rotational frequency, and an operation start detecting means for detecting the start of the operation of the boring bit 2 to the member to be machined based on the operation condition to the first to fourth reference values in the controller.

Description

  The present invention relates to a power tool, and more particularly to a power tool that performs slow idling.

  2. Description of the Related Art Conventionally, in a power tool, for example, a drill that is a drilling tool, so-called slow idling, in which a motor is driven at a low speed at the start of work, may be performed in order to prevent the bit from being displaced from the drilled material at the start of work. In such a power tool, as shown in Patent Document 1, the rotation speed of the motor when there is no load (the rotation speed when the bit is not in contact with the drilled material) and the rotation speed when the load is applied (bit The rotation speed of the motor is rotated at a high speed in a state where the rotation speed of the motor is lower than the threshold value. Yes.

JP 2010-173053 A

  Although the electric tool is configured to maintain a constant rotation speed, a certain degree of rotation speed variation occurs due to the usage environment of the electric tool, manufacturing errors of the motor and the drive system, and the like. If the rotational speed varies more than a certain rotational speed, the rotational speed at the time of load may be higher than a threshold value. In this state, the motor state cannot be detected without detecting the working state. The number cannot shift from low speed to high speed. Also, if this variation varies below a certain number of rotations, the number of rotations is lower than the threshold value even in the no-load state, and even if there is no load, it is lower than the threshold value, so it is always erroneously detected as a load state. There is a risk that the rotational speed will always be high. Therefore, an object of this invention is to provide the electric tool which can detect a working state irrespective of the dispersion | variation in the rotation state of a motor.

  In order to solve the above-described problems, the present invention controls a motor, a housing that houses the motor, a mounting portion that can be mounted with a tip tool that is driven by the motor and processes a workpiece, and controls the rotation of the motor. A control unit, and the control unit includes an operation state detection unit that detects an operation state of the motor or the housing, and a reference value derivation unit that derives a reference value based on the detected operation state. There is provided an electric tool having work start detecting means for detecting the work start of the tip tool on the workpiece based on the operation state with respect to the reference value.

  In the electric tool having the above-described configuration, the control unit starts from the first period when the motor starts rotating to the second period after the first period when the motor is in the high output state. It is preferable that the apparatus further includes output increasing means for increasing the output of the motor, and the output increasing means increases the output of the motor according to the work start detected by the work start detecting means.

  According to such a configuration, the reference value according to the characteristics of the electric power tool can be defined, so that the work state can be detected according to the reference value regardless of the variation in the rotation state of the motor.

  In addition, a time measuring unit that measures the time after the first period is detected by the operation state detecting unit, and a detection of the work start by the work start detecting unit are permitted based on the measurement result measured by the time measuring unit. And a work start detection permitting means.

  According to such a configuration, it is possible to detect the work state in the first period in a state where the low output state is reliably obtained in the first period.

  The reference value deriving means detects the operating state of the motor when there is no load and defines it as the reference value. The work start detecting means detects that the operating state is the reference value after the motor starts rotating. It is preferable to define the start of operation by detecting that the motor has changed to the operating state when the motor is loaded.

  According to such a configuration, since it is possible to detect a decrease in the number of rotations of the motor regardless of the threshold value, it is possible to detect the work state, in particular, that the tip tool has come into contact with the object and started work regardless of variations. be able to.

  The reference value deriving means detects the operating state of the motor when there is no load and derives the operating state when a load is generated at least on the motor from the operating state when the load is not loaded. The work start detecting means may detect that the operation state is on the load generation side of the motor with respect to the reference value after the motor has started to rotate to define the work start. Good.

  According to such a configuration, an optimum threshold value can be obtained for each electric tool. Therefore, when there is no change from the unloaded state to the loaded state in the first period, for example, the working state can be detected even in the electric tool in the loaded state from the start of the work.

  The reference value deriving means detects a first reference value that is set by detecting the operating state of the motor when there is no load, and detects the operating state of the motor when there is no load. And a second reference value for deriving and setting the operation state when a load is generated on the motor from the state, and the work start detection means is configured to determine the operation state after the motor starts rotating. Either the operating state changes from one reference value to the operating state when the motor is loaded, or the operating state is on the load generation side of the motor with respect to the second reference value after the motor starts rotating. Either of these may be detected to define the start of the work.

  In order to solve the above problems, the present invention controls a motor, a housing containing the motor, a mounting portion on which a tip tool driven by the motor to process a workpiece, and a rotation of the motor can be controlled. A control unit for detecting the operation state of the motor or the housing, and a reference value deriving unit for deriving a reference value based on the detected operation state. There is provided an electric tool having work end detection means for detecting work end of the tip tool on the workpiece based on the reference value, and motor stop means for stopping the rotation of the motor based on the work end. .

  In the electric tool having the above-described configuration, the control unit starts from the first period when the motor starts rotating to the second period after the first period when the motor is in the high output state. It is preferable that the apparatus further includes output increasing means for increasing the output of the motor, and the work end detecting means detects the work end after the output of the motor is increased.

  According to such a configuration, the reference value according to the characteristics of the electric power tool can be defined, so that the work state can be detected according to the reference value regardless of the variation in the rotation state of the motor.

  In addition, a time measuring unit that measures the time after the second period is detected by the operating state detecting unit, and a detection of the completion of the work by the work end detecting unit are permitted based on the measurement result measured by the time measuring unit. And a work end detection permitting means.

  According to such a configuration, it is possible to detect the work state in the second period in a state where the high output state is reliably obtained in the second period.

  The reference value deriving means detects the operation state when the tip tool is machining the workpiece and sets it as the reference value. The work end detection means It is preferable to define the end of the operation by detecting from the reference value that the motor has changed to an operating state when there is no load.

  According to such a configuration, since it is possible to detect an increase in the number of rotations of the motor regardless of the threshold value, the working state, in particular, the state where the tip tool is no longer in contact with the object, that is, the work is finished regardless of the variation. Can be detected.

  Further, the reference value deriving means derives the operation state at least when the motor is unloaded from the operation state when the tip tool is machining the workpiece, and the reference value is derived. The work end detection means may define the work end by detecting that the operating state is on the no-load side of the motor with respect to the reference value.

  According to such a configuration, an optimum threshold value can be obtained for each electric tool. Therefore, even when there is no change from the loaded state to the no-load upper level in the second period, that is, when the tip tool is not brought into contact with the object when the second period is reached, it is easy The end of the work can be detected.

  The reference value deriving means detects and sets the operation state when the tip tool is machining the workpiece, and the tip tool with respect to the workpiece. And a fourth reference value for deriving and setting the operation state when the motor is unloaded from the operation state at the time of machining, the work end detection means Is changed from the third reference value to the operating state when the motor is unloaded, or the operating state is on the no-load side of the motor with respect to the fourth reference value. The end of the work may be defined by detection.

  The operating state is preferably a state corresponding to at least one of the number of rotations of the motor, the amount of electric power consumed by the motor, and the amount of vibration applied to the motor and the housing. According to such a configuration, the operation state can be easily detected.

  Further, the operation state is a state according to the rotation speed of the motor, and the control unit includes an actual voltage detection unit that detects an actual voltage of input power, a reference voltage storage unit that stores a reference voltage, An actual rotational speed detecting means for detecting the actual rotational speed of the motor, and the operating state detecting means multiplies the actual rotational speed by a value obtained by dividing the reference voltage by the actual voltage to obtain the rotational speed. It is preferable to detect.

  According to such a configuration, the rotation state detected by the rotation state detection unit can be set to a stable value even when the rotation state according to the voltage fluctuation varies particularly in the AC power source.

  According to the electric tool of the present invention, it is possible to detect the work state regardless of variations in the rotation state of the motor.

Sectional drawing which shows the example which applied the electric tool by embodiment of this invention to the drilling tool. The principal part sectional drawing which shows the distance sensor of the drilling tool by embodiment of this invention. The figure which shows the display part of the drilling tool by embodiment of this invention. The circuit diagram which shows the control circuit part, inverter circuit part, motor, etc. of the drilling tool by embodiment of this invention. The time chart which shows the control which concerns on the drilling work start of the drilling tool by embodiment of this invention. The flowchart which shows the control which concerns on the drilling operation start of the drilling tool by embodiment of this invention. The graph which shows the fluctuation | variation of the input voltage and rotation speed of the drilling tool by embodiment of this invention. The graph which shows the state after correct | amending the fluctuation | variation of the input voltage and rotation speed of the drilling tool by embodiment of this invention. The flowchart which shows the 1st modification of the control which concerns on the drilling operation start of the drilling tool by embodiment of this invention. The flowchart which shows the 2nd modification of the control which concerns on the drilling operation start of the drilling tool by embodiment of this invention. The perspective view which shows the example which applied the electric tool by embodiment of this invention to the portable circular saw. Sectional drawing which shows the example which applied the electric tool by embodiment of this invention to the portable circular saw.

  Hereinafter, the electric tool which concerns on 1st embodiment of this invention is demonstrated based on FIG. 1 thru | or FIG. A drilling tool 1 that is an electric tool shown in FIG. 1 is a rotary hammer drill that drills a material to be drilled W, and a housing is constituted by a handle portion 10, a motor housing 20, and a gear housing 60. In the following, the front-rear direction is defined with the right side in FIG. 1 (the front end side of the drill bit 2) as the front end side of the drilling tool 1, and the handle portion 10 extends from the motor housing 20 in a direction orthogonal to the front-rear direction. The description will be made by defining the vertical direction with the direction as the lower side. Further, the material to be drilled W is located on the front end side of the drilling tool 1. The length of the housing in the front-rear direction of the housing, that is, the length in the left-right direction in FIG. 1 is about 30 cm to 40 cm.

  The handle portion 10 is integrally molded of plastic and has a substantially U-shape, and a motor housing portion 20A that is a part of the motor housing 20 and houses a motor 21 described later is defined on the upper portion thereof. A part of the motor housing 20 is formed. A power cable 11 is attached to the lower portion of the rear portion 10A of the handle portion 10, and a switch mechanism 12 connected to a motor 21 and the like described later is built in. A trigger 13 that can be operated by an operator is mechanically connected to the switch mechanism 12. By operating the trigger 13, the power supply to the inverter circuit unit 102 or the stoppage is switched. Further, the rear portion 10A of the handle portion 10 and immediately below the trigger 13 forms a grip portion 10C that is a portion to be gripped by the middle finger and the ring finger when the user of the drilling tool 1 grips the rear portion 10A.

  In the front part 10B of the handle part 10, a distance sensor 14 directed in the distal direction is provided at the upper part. The distance sensor 14 is composed of an infrared sensor having a wavelength of about 850 nm, and can measure the distance X between the distance sensor 14 and the material to be punched W in the front and rear end directions as a measurement value.

  As shown in FIG. 2, the distance sensor 14 is substantially entirely covered with a resin cover 14A. The rear part of the cover 14A is fixed to the upper part of the front part 10B of the handle part 10 via an elastic member 14B made of rubber. The distance sensor 14 is electrically connected to a microcomputer 110 (FIG. 4) described later. The distance sensor 14 is electrically connected to a hole depth setting button 117 of the input unit 23 described later, and a desired drilling depth can be input to the hole depth setting button 117 as described later. More specifically, the input depth value is about 3 cm to 6 cm.

  The motor housing 20 is provided with an input portion 23 serving as an input terminal (input means) at an upper position on the outer surface thereof, and a motor 21 is accommodated therein. As shown in FIG. 3, the input unit 23 includes a digitally displayed display unit 23A, a depth control function on / off button 116, a hole depth setting button 117, an origin position setting button 118, and a depth correction. A processing on / off button is provided. The depth control function on / off button 116 performs drilling at the depth of a hole set by a hole depth setting button 117 described later (depth control function is on), or depends on the set depth of the hole. Switching between drilling (depth control function off).

  The hole depth setting button 117 sets the depth of the hole to be drilled, and has an UP button 117A and a DOWN button 117B. The origin position setting button 118 sets the origin position by pressing when the drilling tool 1 is set at the origin position for the hole to be drilled. Each of these buttons is connected to a microcomputer 110 described later.

  The motor 21 shown in FIG. 1 is composed of a three-phase DC brushless motor, and the rotation is controlled by a microcomputer 110 described later. The motor 21 includes an output shaft 22 that extends to the front end side and has the front-rear direction as an axial direction. The output shaft 22 outputs a rotational driving force. An axial fan 22 </ b> A is provided at the base of the output shaft 22 so as to be rotatable integrally with the output shaft 22.

  The gear housing 60 is formed by resin molding and is provided on the front end side of the motor housing 20. A first intermediate shaft 61 is coaxially disposed in the gear housing 60 so as to extend the output shaft 22 and is rotatably supported by a bearing 63. The rear end of the first intermediate shaft 61 is connected to the output shaft 22. A fourth gear 61 </ b> A is provided at the tip of the first intermediate shaft 61. In the gear housing 60, a second intermediate shaft 72 is supported in parallel with the output shaft 22 by a bearing 72B so as to be rotatable about its axis.

  A fifth gear 71 that meshes with the fourth gear 61 </ b> A is coaxially fixed to the rear end portion of the second intermediate shaft 72. A gear portion 72A is formed on the front end side of the second intermediate shaft 72 and meshes with a sixth gear 73 described later. A cylinder 74 is provided in the gear housing 60 at a position above the second intermediate shaft 72. The cylinder 74 extends in parallel with the second intermediate shaft 72 and is rotatably supported. The sixth gear 73 is fixed to the outer periphery of the cylinder 74, and the cylinder 74 can rotate around its axis by meshing with the gear portion 72A described above.

  A tool holding portion 15 is provided on the front end side of the cylinder 74, and a drill bit 2 described later is detachably attached thereto. The intermediate portion of the second intermediate shaft 72 is spline-engaged with a clutch 76 that is urged toward the rear end side by a spring. The clutch 76 is connected to a hammer drill by a change lever (not shown) provided in the gear housing 60. The mode and the drill mode can be switched. On the motor 21 side of the clutch 76, a motion conversion unit 80 that converts rotational motion into reciprocating motion is externally mounted on the second intermediate shaft 72. The arm 80 </ b> A of the motion converter 80 is provided so as to be able to reciprocate in the front-rear direction of the drilling tool 1 by the rotation of the second intermediate shaft 72.

  A piston 82 is provided in the cylinder 74. The piston 82 is mounted so as to reciprocate in a direction parallel to the second intermediate shaft 72 and to be slidable in the cylinder 74. A striking element 83 is housed in the piston 82, and an air chamber 84 is defined in the cylinder 74 between the piston 82 and the striking element 83. At a position opposite to the air chamber side of the striker 83, an intermediate element 85 is supported in the cylinder 74 so as to be slidable in the direction of movement of the piston 82. A punch bit 2 as a tip tool is located at a position opposite to the striker side of the intermediate piece 85. Therefore, the striker 83 can strike the drill bit 2 via the intermediate piece 85.

  When the clutch 76 is switched to the hammer drill mode, the second intermediate shaft 72 and the motion conversion unit 80 are connected by the clutch 76. The motion conversion unit 80 is configured to be connected to the piston 82 provided in the cylinder 74 via the piston pin 81.

  The drill bit 2 is a drill bit, and as shown in FIG. 1, includes a barrel portion 2A having a round bar shape and a spiral groove, and a tapered tip portion positioned at the tip of the barrel portion. The front end portion is the leading end, and a hole can be drilled in the material to be drilled W. The drill bit 2 can be attached to and detached from the tool holding portion 15 and can be exchanged.

  Next, the circuit configuration of the control circuit unit including the microcomputer 110 serving as a calculation unit (control unit), the rectifier circuit 101, the inverter circuit unit 102, and the motor 21 will be described with reference to FIG. The control circuit unit includes a switch operation detection circuit 111, an applied voltage setting circuit 112, an input voltage detection circuit 113, a current detection circuit 114, a rotor position detection circuit 115, a motor rotation number detection circuit 116, and a control signal. An output circuit 119, a distance depth setting circuit and an origin position setting circuit (not shown) are provided.

  The switch operation detection circuit 111 detects whether or not the trigger 13 is pushed and outputs the detection result to the microcomputer 110. The applied voltage setting circuit 112 sets the PWM duty of the PWM drive signal for driving the switching elements Q <b> 1 to Q <b> 6 of the inverter circuit unit 102 according to the target value signal output from the trigger 13, and outputs the PWM duty to the microcomputer 110. .

  The input voltage detection circuit 113 detects a voltage between the rectifier circuit 101 and the inverter circuit unit 102 and outputs the detection result to the microcomputer 110. The current detection circuit 114 detects the amount of current between the rectifier circuit 101 and the inverter circuit unit 102 and outputs the detection result to the microcomputer 110. The rotor position detection circuit 115 detects the rotational position of the rotor of the motor 21 based on the rotational position detection signal output from the Hall IC 21A, and outputs the detection result to the microcomputer 110. The motor rotation number detection circuit 116 is an operation state detection unit, detects the rotation number of the motor 21 from the rotation position detected by the rotor position detection circuit 115, and outputs the detection result to the microcomputer 110. A hole depth setting button 117 is connected to a distance depth setting circuit (not shown), and when a hole is drilled with the drill bit 2 up to the value input from the hole depth setting button 117 with the depth control function turned on, A signal for stopping the power supply to the motor 21 is output to the microcomputer 110. An origin position setting button 118 is connected to an origin position setting circuit (not shown), and when the origin position setting button 118 is pressed, a signal related to the origin setting of the hole to be drilled by the drill bit 2 is output to the microcomputer 110. is doing.

  The microcomputer 110 calculates a PWM duty target value (power save mode: 70%, full power mode: 100%) based on the output from the applied voltage setting circuit 112. Further, based on the output from the rotor position detection circuit 115, a stator winding to be properly energized is determined, and output switching signals H1 to H3 and PWM drive signals H4 to H6 are generated. The PWM drive signals H4 to H6 are output with the duty width determined based on the target value of the PWM duty. The control signal output circuit 119 outputs the output switching signals H1 to H3 and the PWM drive signals H4 to H6 generated by the microcomputer 110 to the inverter circuit unit 102.

  The inverter circuit unit 102 is supplied with AC power from a commercial power supply via the rectifier circuit 101. In the inverter circuit unit 102, the switching element is driven based on the output switching signals H1 to H3 and the PWM drive signals H4 to H6, and the stator winding to be energized is determined. Further, the PWM drive signal is switched at the target value of the PWM duty. As a result, a three-phase AC voltage having an electrical angle of 120 ° is sequentially applied to the three-phase stator windings (U, V, W) of the motor 21.

  The microcomputer 110 includes a storage device 120 that is a storage unit such as a ROM, and a timer 120A. The storage device 120 functions as a storage unit that stores each reference value to be described later. The time is measured. This timer 120A corresponds to a time measuring means.

  When the motor 21 of the drilling tool 1 having the above configuration is driven, the rotational output of the motor 21 is transmitted to the second intermediate shaft 72 via the first intermediate shaft 61, the fourth gear 61 </ b> A, and the fifth gear 71. The rotation of the second intermediate shaft 72 is transmitted to the cylinder 74 by the meshing of the gear portion 72A and the sixth gear 73, and the rotational force is transmitted to the drill bit 2. When the clutch 76 is moved to the hammer drill mode, the clutch 76 is coupled to the motion conversion unit 80, and the rotational driving force of the second intermediate shaft 72 is transmitted to the motion conversion unit 80. In the motion converter 80, the rotational driving force is converted into a reciprocating motion of the piston 82 via the piston pin 81. The pressure of the air in the air chamber 84 defined between the striking element 83 and the piston 82 by the reciprocating motion of the piston 82 repeatedly rises and falls to give the striking force to the striking element 83. The striking element 83 moves forward and collides with the rear end surface of the intermediate element 85, and the striking force is transmitted to the drill bit 2 (not shown) via the intermediate element 85. In this manner, in the hammer drill mode, a rotational force and a striking force are simultaneously applied to the drill bit 2 (not shown).

  When the clutch 76 is in the drill mode, the clutch 76 disconnects the connection between the second intermediate shaft 72 and the motion conversion unit 80, and only the rotational driving force of the second intermediate shaft 72 passes through the gear portion 72 </ b> A and the sixth gear 73. To the cylinder 74. Therefore, only the rotational force is applied to the drill bit 2.

  In the above-described hammer drill mode or drill mode, the drilling tool 1 is held so that the center axis of the drill bit 2 (axis parallel to the front-rear direction of the drill bit 2) and the plane of the material to be drilled W are orthogonal to each other. Then, the depth control function ON / OFF button 116 is pressed to turn the microcomputer 110 into the depth control function ON state. In this state, the UP button 117A and the DOWN button 117B are operated to set the drilling depth, the origin position setting button 118 is operated to set the origin position, and then the trigger 13 is pulled to perform the drilling. During drilling, the distance sensor 14 always detects the drilling depth. When the drilling depth reaches a set value, the microcomputer 110 automatically stops the power supply to the motor 21.

  When the perforation bit 2 is perforated on the material to be perforated W, if the perforation bit 2 is rotated at a high speed (full power mode: PWM duty 100%) from the beginning of perforation, the perforation bit 2 is repelled from the perforated material W, Appropriate work may not be performed. Therefore, in order to avoid this, at the beginning of drilling, drilling is performed at low rotation (power save mode: PWM duty 70%), and after a certain period of time and after load detection, high rotation (full power mode: PWM duty 100%) The so-called slow idling is performed in which the work is performed at an increased rotational speed.

  As control related to this slow idling, as shown in FIG. 5, the operator pulls the trigger 13 to rotate the motor 21 at a low speed in the first period after the start of rotation (after the start of work). After a rising period in which the number of rotations of the motor 21 is increased, the process proceeds to a second period in which the motor 21 is rotated at a high speed. In the second period, after the drilling operation is completed, the process proceeds to a third period (not shown) in which the motor 21 is rotated at a low speed again through a descending period in which the rotational speed of the motor 21 is decreased. Then, in the third period, when the operator releases his hand from the trigger 13, the rotation of the motor 21 is stopped.

  When the trigger 13 is pulled in a state in which the punching bit 2 is in contact with the material to be punched in advance (when the work is started), the load applied to the motor 21 is maintained from the start of the work. As indicated by a solid line L1 in FIG. 5, in the first period, the motor 21 maintains a low rotation state and there is no particular fluctuation in the rotation speed.

  On the other hand, when the trigger 13 is pulled in a state where the drill bit 2 is not in contact with the material to be drilled W (when the work is started), as shown by the broken line 11 in FIG. Since the motor 21 is rotated by the load, the rotational speed increases at the beginning of the first period, and reaches the maximum rotational speed N1max in the power save mode. Thereafter, at time t1, the drilling bit 2 comes into contact with the material to be drilled W and starts drilling, so that a load is applied to the motor 21 and the rotational speed is reduced to converge to the same rotational speed as the solid line L1.

  When shifting to the second period through the ascending period, if the operator has already drilled to a predetermined drilling depth, the operator stops the pressing of the drilling tool 1 against the drilled material W. No load is applied. When the drill bit 2 penetrates the material to be punched W, the tip of the punch bit 2 is not in contact with the material to be drilled W, so that no load is applied to the motor 21. In this case, as indicated by a broken line 12 in FIG. 5, the rotational speed increases at the initial stage of the second period and reaches the maximum rotational speed in the full power mode.

  On the other hand, when the drilling operation is performed while the tip of the drilling bit 2 is still in contact with the material to be drilled W in the second period, a load is applied to the motor 21, so that the solid line L2 in FIG. The increase in the rotational speed is suppressed, and reaches the minimum rotational speed N2min in the full power mode at the start of the second period. Thereafter, by drilling to a predetermined drilling depth at time t2, the motor 21 is not loaded, and the rotational speed increases and converges to the same rotational speed as the broken line l2 (reaches the maximum rotational speed in the full power mode).

  The transition from the first period to the second period is performed based on the number of rotations in the first period. Specifically, the maximum rotational speed N1max (first reference value) in the first period and a value N09 (second reference value) 90% of the maximum rotational speed N1max are stored in the storage device 120 in advance, and this Whether the rotational speed N of the motor 21 decreases to 90% or less of the first reference value after reaching the first reference value at the start of the first period based on the reference value (determination corresponding to the broken line 11 in the time chart) Or when it is determined whether the rotational speed N remains below the second reference value without increasing after the start of the first period (determination corresponding to the solid line L1 in the time chart). Then, after the rising period, the process proceeds to the second period. In the present embodiment, the second reference value is equal to 90% of the first reference value.

  The transition from the second period to the third period is performed based on the number of rotations in the second period. Specifically, the minimum rotation speed N2min (third reference value) in the second period and a value N11 (fourth reference value) that is 110% of the minimum rotation speed N2min are stored in the storage device 120. Based on the reference value, at the start of the second period, whether the rotational speed N of the motor 21 increases to 110% or more of the third reference value after showing the third reference value or a value smaller than the third reference value (time A determination corresponding to the solid line L2 of the chart), or whether the state exceeds the fourth reference value at the start of the second period (determination corresponding to the broken line l2 of the time chart). Then, after the falling period, the process proceeds to the third period. In the present embodiment, the fourth reference value and 110% of the third reference value are equal.

  Control performed by the microcomputer 110 according to the time chart will be described with reference to the flowchart of FIG. First, in S01, the first reference value to the fourth reference value stored in advance from the storage device 120 are read into the microcomputer 110, and then the process proceeds to S02 to determine whether or not the trigger 13 is pulled. If it is determined in S02 that the trigger 13 has been pulled, the process proceeds to S03 to start the motor 21 in the power save mode. Next, it progresses to S04 and it is judged whether the present mode is a power save mode. Since the power save mode is currently activated in S03 (S04: YES), the process proceeds to S05, the PWM duty is set to 70%, and then the process proceeds to S06, where the motor speed detection circuit 116 causes the motor speed to be increased. N is detected. Based on the detected motor rotation speed N, it is determined in S07 whether or not the motor rotation speed N exceeds the first reference value. If it is determined in S07 that the motor rotational speed N exceeds the first reference value (S07: YES), the process proceeds to S08, and the motor rotational speed N that has exceeded this is stored as a new first reference value. 120, and proceeds to S09. If it is determined in S07 that the motor rotational speed N does not exceed the first reference value (S07: NO), the process proceeds to S09 while avoiding S08.

  In S09, it is determined whether or not the current motor rotation speed N is equal to or less than the second reference value, that is, 90% or less of the maximum rotation speed N1max. If it is determined that the motor rotation speed N is equal to or less than the second reference value (S09: YES), the process proceeds to S10, shifts to the full power mode, proceeds to S11, and the trigger 13 remains pulled ( S11: NO), loop to S04. If it is determined that the motor rotation speed N is greater than or equal to the second reference value (S09: NO), the process proceeds to S11 while avoiding S10, and if the trigger 13 remains pulled (S11: NO), the process proceeds to S04. Since it is still in the power save mode, the process proceeds from S04 to S05, and the above loop is repeated until S09 is determined as YES. Here, S09 is determined as YES, that is, the tip of the punch bit 2 is in contact with the material to be punched W and the load is generated and the rotational speed of the motor 21 is reduced at least in the time chart of FIG. It is after t1. Moreover, it is before time t1 in the time chart that S09 is determined to be NO. The control related to S07 (YES) -S08-S09 (YES) and S07 (YES) -S08-S09 (NO) corresponds to the broken line 11 in the time chart shown in FIG. Further, the control related to S07 (NO) -S09 (YES) corresponds to the solid line L1 of the time chart shown in FIG. A flow including S5 to S10 corresponds to the first period.

  In S04 that loops from S10 to S11, since it is currently in the full power mode, it is determined that S04 is NO, the process proceeds to S13, the PWM duty is set to 100%, and then the process proceeds to S14 to detect the motor speed. The circuit 116 detects the motor rotation speed N. Based on the detected motor speed N, it is determined in S15 whether or not the motor speed N is below the third reference value. If it is determined in S15 that the motor rotation speed N is below the third reference value (S15: YES), the process proceeds to S16, and the motor rotation speed N that has decreased is stored as a new third reference value. 120, and proceeds to S17. If it is determined in S15 that the motor rotation speed N is not lower than the third reference value (S15: NO), S16 is avoided and the process proceeds to S17. In S17, it is determined whether or not the current motor speed N is equal to or greater than the fourth reference value, that is, 110% or more of the maximum speed N1max. If it is determined that the motor rotational speed N is equal to or greater than the fourth reference value (S17: YES), the process proceeds to S18, shifts to the power save mode, and proceeds to S11. If it is determined that the motor rotational speed N is equal to or lower than the fourth reference value (S17: NO), the process proceeds to S11 while avoiding S18, and if the trigger 13 remains pulled (S11: NO), the process proceeds to S04. Since the loop is still in the full power mode, the process proceeds from S04 to S13, and the above loop is repeated until S17 is determined to be YES. Here, S17 is determined as YES at least after time t2 in the time chart of FIG. 4, and S17 is determined as NO before time t2 in the time chart. S15 (YES) -S16-S17 (YES) and S15 (YES) -S16-S17 (NO) correspond to the solid line L2 of the time chart shown in FIG. S15 (NO) -S17 (YES) corresponds to the broken line 12 in the time chart shown in FIG. A flow including S13 to S18 corresponds to the second period.

  In S17, when it is determined that the motor rotation speed N is equal to or greater than the fourth reference value (S17: YES), since the drilling operation is finished, the flow of S17 (YES) -S18-S11 is performed. After the rotation speed of the motor 21 is decreased in S18, the trigger 13 is returned to the original in S11 (S11: YES), the process proceeds to S12, the motor 21 is stopped, the work is stopped, and the process loops to S02. The flow including S11-S12 corresponds to the third period.

  In the flowchart, S08 and S16 correspond to reference value deriving means, and S08 and S17 correspond to work start detecting means and work end detecting means. S10 corresponds to the output increasing means, and S12 corresponds to the motor stopping means.

  The rotation of the motor 21 according to the above control is based on the applied voltage set by the applied voltage setting circuit 112 as described above. This applied voltage is set based on the input voltage Ein when the AC power from the commercial power source is converted to DC by the rectifier circuit 101 as described above, but this input voltage is not necessarily smooth, as shown in FIG. And the number of rotations of the motor 21 also varies according to the variation. When the rotational speed of the motor 21 fluctuates, for example, in the first period, it may be determined that the motor rotational speed N is originally higher than the first reference value but not higher. Therefore, in order to reduce such misjudgment, as shown in FIG. 8, when a reference voltage Eb of about 230 V is defined as an example and the actual rotational speed of the motor 21 is defined as the actual rotational speed No, the motor rotational speed N = No × (Eb / Ein). By defining the motor rotational speed N in this way, the influence of fluctuations in the input voltage Ein can be eliminated, and when the motor 21 is in the same load state, the motor rotational speed N can be smoothed. Such erroneous determination can be reduced.

  In the present embodiment, the control based on the number of revolutions shown in FIG. 6 is performed by paying attention to a decrease in the number of revolutions based on the load generated when the perforating bit 2 perforates the material to be perforated. On the other hand, the control may be performed by paying attention to an increase in the amount of current based on the generation of a load when the punching bit 2 punches the workpiece W. Specifically, control is performed based on the flowchart shown in FIG. The flowchart relating to the amount of current shown in FIG. 9 has the same configuration as the flowchart relating to the number of revolutions shown in FIG. 6, and is a chart in which the number of revolutions is replaced with the amount of current. Further, as described above, when the load on the motor 21 is increased, the rotational speed is decreased, but the amount of current is increased. Therefore, the magnitude relationship of the flowchart of FIG. 9 is set opposite to the flowchart of FIG. Therefore, the first reference value and the third reference value according to the flowchart of FIG. 9 correspond to the minimum current amount I1min corresponding to the maximum rotation speed N1max in the first period of the motor 21 and the minimum rotation speed N2min in the second period, respectively. The maximum current amount I2max. The second reference value and the fourth reference value are 110% of the first reference value and 90% of the third reference value, respectively. Further, for example, it is determined whether or not the motor rotation speed N is higher than the first reference value in S07 of FIG. 6, whereas in S27 of FIG. 9, whether or not the motor current value I is lower than the first reference value. Determine whether.

  In this way, the same control as the rotation speed N can be performed based on the current amount I. In addition to the amount of current, for example, attention may be paid to vibration generated in the drilling tool 1, and control may be performed by detecting the amount of vibration using an acceleration sensor. The amount of vibration is large when the material to be drilled W is punched by the punching bit 2 and when it is not punched, and the amount of vibration in the full power mode is large in the power save mode and the full power mode. Become. Since the magnitude relationship between the vibration amounts is the same as the magnitude relationship between the current amount I during perforation and non-perforation, and between the power save mode and the full power mode, the same flowchart as the flowchart of the current amount I shown in FIG. Can be controlled by

  In the control relating to the rotation speed described above, as shown in FIG. 6, it is determined whether the power save mode or the full power mode is selected in S04, and each of the PWM in the power save mode and the full power mode is determined in S05 and S13. The duty value is set, and assuming that the predetermined PWM duty value is reached, the flow after S06 or S14 is executed. On the other hand, as shown in FIG. 10, after determining whether the power save mode or the full power mode is selected in S104, the PWM duty values of the power save mode and the full power mode are set in S105 and S114. Thereafter, it may be determined whether or not a predetermined time has elapsed after shifting to the predetermined mode in S106 and S115.

  Specifically, for example, at time pret1 (FIG. 5), the PWM duty value is set to 70% as a power save mode in S105. Next, the process proceeds to S106, and it is determined whether or not a predetermined time (period p1 in FIG. 5) has elapsed by the timer 120A after shifting to the power saving mode. If the predetermined time has not elapsed (S106: NO), the process proceeds to S113, and the trigger 13 is still being pulled (S113: NO). Therefore, the process loops to S104, and further proceeds to S105 and S106. The flow is repeated until a predetermined time has passed.

  If the predetermined time has elapsed in S106 (S106: YES), the process proceeds to S107 to detect the motor rotation speed, and thereafter the same processing as in the flowchart of FIG. 6 is performed.

  At time pret2 (FIG. 5), the PWM duty value is set to 100% in S114 as the full power mode. Next, proceeding to S115, it is determined whether or not a predetermined time (period p2 in FIG. 5) has elapsed by the timer 120A after shifting to the full power mode. If the predetermined time has not elapsed (S115: NO), the process proceeds to S113, and the trigger 13 is still being pulled (S113: NO). Therefore, the process loops to S104, and further proceeds to S114 and S115. The flow is repeated until a predetermined time has passed.

  If the predetermined time has elapsed in S115 (S115: YES), the process proceeds to S116 to detect the motor rotation speed, and thereafter the same processing as in the flowchart of FIG. 6 is performed.

  By setting the PWM duty value for each of the power save mode and full power mode in this way and detecting the motor speed after a predetermined time has elapsed, the motor can be rotated in a state where the power save mode or full power mode has been entered. The number of rotations can be detected, and the number of rotations in the power save mode or the full power mode can be accurately detected. S106 and S115 correspond to work start detection permission means and work end detection permission means, respectively.

  In the flowchart shown in FIG. 6, the first reference value (maximum rotational speed N1max) and the third reference value (minimum rotational speed N2min) are only updated in the flowchart (S08 and S16 in FIG. 6). However, in addition to this, a flow for resetting the first reference value and the third reference value may be provided. Specifically, as shown in FIG. 10, the third reference value used in the full power mode is reset in S112 after the transition from the power save mode to the full power mode, and the power save mode is changed from the full power mode to the power save mode. After S120, the first reference value used in the power save mode is reset in S121.

  By resetting the first reference value and the third reference value in this way, the abnormal value is updated as the first reference value (maximum rotational speed N1max) and the third reference value (minimum rotational speed N2min) in S109 and S118. Even if it is, an abnormal value can be eliminated.

  Although the drilling tool has been described as the power tool according to the present embodiment, the present invention is not limited thereto, and any power tool that processes a workpiece with a tip tool can be applied. For example, the present invention can also be applied to a portable circular saw 201 as shown in FIG. The portable circular saw 201 includes a base 202 placed on a plate material (not shown) that is a workpiece, a housing 203 provided on the base 202, and a saw blade 201A for cutting the plate material (not shown). ing. As shown in FIG. 12, the housing 203 is provided with a motor 204 and a gear mechanism 205 to which the driving force of the motor 204 is transmitted, and the above-described saw blade 201 </ b> A is connected to the gear mechanism 205. 201A is rotationally driven. As shown in FIG. 11, the housing 203 is provided with a trigger 231 that is connected to an external power source and controls ON / OFF of the motor 204 (FIG. 12), and is a control device that controls the power supplied to the motor 204. A microcomputer (not shown) is provided.

  In order to cut the plate material in the portable circular saw 201, the trigger 231 is moved in contact with the plate material while the saw blade 201A is rotated, and the trigger is started when the saw blade 201A is contacted with the plate material in advance. In some cases, the saw blade 201A is rotated while the saw blade 201A is rotated. In any case, at the start of cutting, the rotational speed of the saw blade 201A is reduced (power saving mode), and the rotational speed of the saw blade 201A is set to the maximum value (full power mode) in a state where the cutting has been reliably advanced. Accordingly, the saw blade 201A is not repelled from the plate material at the start of cutting, and the cutting operation can be suitably performed.

  Therefore, as in the above-described embodiment, the first to fourth reference values are set in the portable circular saw 201, and the same control as the flowchart of FIG. The working state can be detected, and the optimum cutting state (either power save mode or full power mode) can be selected.

  In addition to this modification, the present invention can be applied to an electric tool for cutting a workpiece, for example, a jigsaw or a saver saw, or an electric tool for cutting / polishing a sander or the like other than cutting and drilling. Needless to say.

DESCRIPTION OF SYMBOLS 1 .... Drilling tool 2 .... Drilling bit 2A ... Body part 10A ... Rear part 10B ... Front part 10C ... Holding part 11 ... Power cable 12 ... Switch mechanism 13 ... Trigger -Distance sensor 14A-Cover 14B-Elastic member 15-Tool holding part 20-Motor housing 20A-Motor housing part 21-Motor
22. ・ Output shaft 22A ・ ・ Axial fan 23 ・ ・ Input 23A ・ ・ Display 23B ・ ・ Correction on / off button 60 ・ ・ Gear housing 61 ・ ・ First intermediate shaft 61A ・ ・ Fourth gear 63 ・・ Bearing 71 ・ ・ Fifth gear
72 ·· Second intermediate shaft 72A ·· Gear part 72B ·· Bearing 73 ·· Sixth gear
74 ·· Cylinder 76 · · Clutch 80 · · Motion conversion part 80A · · Arm
81..Piston pin 82..Piston 83..Batter 84..Air chamber
85 .. Meson 101 .. Rectifier circuit 102 .. Inverter circuit section
110..Microcomputer 111..Switch operation detection circuit 112..Applied voltage setting circuit 113..Input voltage detection circuit 114..Current detection circuit 115..Rotor position detection circuit 116..Motor rotation speed detection circuit 116 .. Control function ON / OFF button 117 .. Setting button 117 A.. UP button 117 B... DOWN button 118 .. Origin position setting button 119 .. Control signal output circuit 120.

Claims (14)

A motor,
A housing containing the motor;
A mounting portion capable of mounting a tip tool driven by the motor to process the workpiece;
A control unit for controlling the rotation of the motor,
The control unit includes an operation state detection unit that detects an operation state of the motor or the housing, a reference value derivation unit that derives a reference value based on the detected operation state, and the operation state with respect to the reference value And a work start detecting means for detecting a work start of the tip tool on the workpiece. The controller increases the output of the motor from the first period when the motor starts at a low output state to the second period after the first period when the motor starts at a high output state. It further has an output increasing means,
The power tool according to claim 1, wherein the output increasing means increases the output of the motor in accordance with the work start detected by the work start detecting means. Time measuring means for measuring the time after the first period is detected by the operating state detecting means;
The power tool according to claim 2, further comprising work start detection permission means for permitting the work start detection means to detect the work start based on the measurement result measured by the time measurement means. The reference value deriving means detects the operating state of the motor when there is no load and defines it as the reference value.
The work start detecting means detects the change of the operation state from the reference value to the operation state at the time of loading of the motor after the motor starts rotating, and defines the work start. The power tool according to any one of claims 1 to 3. The reference value deriving means detects the operating state of the motor when there is no load and derives the operating state when at least a load is generated in the motor from the operating state of the no load. As stipulated as
The work start detecting means detects that the operation state is on the load generation side of the motor with respect to the reference value after the motor starts rotating, and defines the work start. The power tool according to any one of claims 1 to 3. The reference value deriving means detects a first reference value that is set by detecting the operating state of the motor when there is no load, and detects the operating state when the motor is not loaded, and the operating state when the motor is not loaded And at least a second reference value for deriving and setting the operating state when a load is generated on the motor,
The work start detection means detects that the operation state has changed from the first reference value to the operation state at the time of loading of the motor after the motor has started rotating, or the operation state has changed after the motor has started rotating. 4. The operation start is defined by detecting any one of the load generation side of the motor with respect to the second reference value. 5. Power tools. A motor,
A housing containing the motor;
A mounting portion capable of mounting a tip tool driven by the motor to process the workpiece;
A control unit for controlling the rotation of the motor,
The control unit includes operating state detecting means for detecting an operating state of the motor or the housing, reference value deriving means for deriving a reference value based on the detected operating state, and the tip based on the reference value An electric tool comprising: work end detection means for detecting work end of the tool on the workpiece; and motor stop means for stopping rotation of the motor based on the work end. The controller increases the output of the motor from the first period when the motor starts at a low output state to the second period after the first period when the motor starts at a high output state. It further has an output increasing means,
8. The power tool according to claim 7, wherein the work end detection means detects the work end after the output of the motor is increased. Time measuring means for measuring the time after the second period is detected by the operating state detecting means;
9. The electric tool according to claim 8, further comprising work end detection permission means for permitting the work end detection means to detect the work end based on the measurement result measured by the time measurement means. The reference value deriving means detects the operation state when the tip tool is machining the workpiece and sets it as the reference value,
The work end detection means detects the change of the operation state from the reference value to the operation state when the motor is not loaded, and defines the end of the operation. The power tool according to any one of 9. The reference value deriving means derives the operation state at least when the motor is unloaded from the operation state when the tip tool is machining the workpiece and obtains the reference value as the reference value. Set,
10. The work end detection unit detects the operation state on the no-load side of the motor with respect to the reference value, and defines the work end. The electric tool according to one. The reference value deriving means detects a third reference value that is set by detecting the operation state when the tip tool is machining the workpiece, and the tip tool is set with respect to the workpiece. Defining a fourth reference value to be derived and set at least when the motor is unloaded from the operating state when machining,
The work end detection means determines that the operating state has changed from the third reference value to the operating state when the motor is unloaded, or the operating state is unloaded from the motor with respect to the fourth reference value. The power tool according to any one of claims 7 to 9, wherein the end of the work is defined by detecting either one of the two.   The operation state is a state corresponding to at least one of a rotation speed of the motor, an amount of electric power consumed by the motor, and an amount of vibration applied to the motor and the housing. The power tool according to any one of claims 1 to 12. The operating state is a state according to the rotational speed of the motor,
The control unit further includes an actual voltage detection unit that detects an actual voltage of the input power, a reference voltage storage unit that stores a reference voltage, and an actual rotation number detection unit that detects the actual rotation number of the motor. And
13. The operating state detecting means detects the rotational speed by multiplying the actual rotational speed by a value obtained by dividing the reference voltage by the actual voltage. The electric tool as described in.

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