JP6705632B2 - Rotary impact tool - Google Patents

Description

The present invention relates to a rotary impact tool configured to rotate by a rotational force of a motor and apply an impact force in a rotational direction when a torque of a predetermined value or more is externally applied.

This type of rotary impact tool includes a hammer mechanism that includes a hammer that rotates by receiving the rotational force of a motor and an anvil that rotates by receiving the rotational force of the hammer. In the striking mechanism, when a torque greater than a predetermined value is applied to the anvil from the outside, the hammer disengages from the anvil and idles, and strikes the anvil in the rotation direction (see, for example, Patent Document 1).

Therefore, according to the rotary impact tool, when the motor is rotated in the forward direction to fix objects such as screws and nuts to the plates and bolts, it is possible to firmly tighten the objects by hitting the anvil with a hammer. it can. Further, when tightening the object is loosened, the motor is rotated in the direction opposite to the direction in which the object is tightened, and the hammer strikes the anvil, whereby the object can be easily tightened.

JP, 2010-207951, A

By the way, in the above-described conventional rotary impact tool, for example, when the user operates the operation unit such as the trigger switch with the maximum operation amount, by driving the motor with the maximum drive power with the drive duty of 100%, Rotate the motor (and thus the tool bit) at high speed.

However, if the motor is driven at a high speed immediately after the start of driving in this way, the tool bit such as a driver bit easily comes off from an object such as a screw, and tightening by the striking mechanism may not be performed properly.

For example, when fixing a long screw to a work material with a rotary impact tool, if the impact is started when the long screw is not sufficiently inserted into the work material, a sudden load change at the start of impact and deflection of the long screw The tool bit may come off the screw head and damage the work material, the tool bit, the screw head, or the like.

One object of the present invention is to prevent the tool bit from coming off the object after the impact is generated by switching the control of the motor before and after the impact is started in the rotary impact tool.

A rotary impact tool according to one aspect of the present invention includes a motor, an impact mechanism, an impact detector, and a controller.
The striking mechanism has a hammer, an anvil, and a mounting portion, like the above-described conventional rotary striking tool, and when a torque greater than a predetermined value is applied to the anvil from the outside, the hammer disengages from the anvil and slips. (By extension, the object mounted on the mounting portion) is hit in the rotation direction.

The striking detection unit is for detecting striking of the anvil by the hammer of the striking mechanism, and the control unit is for driving and controlling the motor so that the motor is in a target rotation state.
Then, after the drive of the motor is started, the control unit detects the impact by the impact detection unit, and during the initial drive period until a predetermined period elapses, the motor is rotated at a speed lower than the target rotation state. Set the controlled variable.

Further, the control unit switches the control amount of the motor to the final control amount corresponding to the target rotation state after the lapse of the initial drive period in which the motor is driven at a speed lower than the target rotation state, and controls the motor to the target rotation state. ..

Therefore, according to the rotary impact tool, even if the rotational state that requires the maximum drive power of the motor is set as the target rotational state, after the drive of the motor is started, the impact by the impact mechanism is started and the predetermined period elapses. Until then, the increase in rotation of the motor will be suppressed.

Therefore, during the initial drive period, the striking force by the striking mechanism will be suppressed, and when the striking mechanism is started with the object such as the long screw not sufficiently entering the work material, It is possible to prevent the tool bit from coming off the object.

Also, if the initial driving period is set so that the striking by the striking mechanism is performed during that period, the objects such as long screws are firmly fixed to the work material by the striking performed during the initial driving period. Can be made

Then, when the initial drive period elapses, the control amount of the motor is switched to the final control amount, and the rotation of the motor increases, so that the striking force by the striking mechanism becomes stronger and the object such as the long screw becomes the work material. The time required for tightening can be suppressed.

Here, the control unit may determine that the initial drive period has elapsed when the impact detection unit detects the impact a predetermined number of times after starting the driving of the motor. Alternatively, it may be determined that the initial drive period has elapsed when a preset time has elapsed after the impact was detected by the impact detector after the motor was started.

That is, the initial drive period from the start of driving the motor until the control amount is switched to the final control amount may be set by the number of hits by the hitting mechanism or by the elapsed time after the start of hitting by the hitting mechanism. Good.

On the other hand, the control unit may be configured to drive the motor by so-called open-loop control, which simply controls the drive power when the motor is driven (for example, the current supplied to the motor and the drive duty ratio during PWM control). Good.

In addition, the control unit detects the rotation speed of the motor through the speed detection unit and controls the rotation speed of the motor so that the detected rotation speed becomes the target rotation speed. The rotation control (so-called feedback control) is performed. May be configured to drive the motor.

When the control unit is configured to drive the motor by feedback control, the control amount of the motor is switched with the lapse of the initial drive period by changing the target rotational speed of the feedback control to the higher speed side than that during the initial drive period. You may make it implement by switching to.

That is, when the motor is drive-controlled by the feedback control, the control amount for controlling the drive power of the motor is set according to the deviation between the rotation speed of the motor and the target rotation speed.
Therefore, if the target rotation speed during the initial drive period is set low and the target rotation speed after the initial drive period elapses is switched to the high speed side, the control unit is configured to drive the motor by feedback control. However, the effects described above can be exhibited.

Next, for the rotary impact tool, the operation mode for selecting from a plurality of operation modes having different target rotation states, for example, high speed and low speed, high speed, medium speed and low speed,... An operation unit may be provided.

Then, in this case, the control unit adjusts the control amount so that the rotation speed of the motor becomes high speed/low speed or high speed/medium speed/low speed according to the operation mode set via the operation unit. It should be set.

In addition, the control unit sets the control amount of the motor so that the motor rotates at a speed lower than the target rotation state during the initial drive period for each operation mode, and when the initial drive period elapses, the control amount of the motor is set to the target. It may be configured to switch to the final control amount corresponding to the rotation state.

On the other hand, when multiple operation modes can be selected in this way, in an operation mode in which the motor rotation speed is set low, even if the control amount is set to the final control amount immediately after the start of driving the motor, the impact occurs. Sometimes the tool bit is less likely to fall off the object.

Therefore, when the operation mode set via the operation unit is the low speed mode in which the motor is rotated at a speed lower than the rotation speed in the other operation modes, the control unit determines the target rotation state in the low speed mode. The driving of the motor may be started with the final control amount corresponding to.

That is, in the low speed mode, the control amount may not be switched after the motor starts to be driven, but the motor drive may be started with the final control amount corresponding to the target rotation state (low speed in this case).

In this way, in the low speed mode, the control amount during the initial drive period is set to the control amount that drives the motor at a speed lower than the target rotation state, so that the rotation speed of the motor before the impact occurs becomes low. It can be suppressed that the time required for tightening the object is too long.

By the way, as described above, if the control amount is switched while the motor is being driven, the rotation speed of the motor may suddenly change due to the switching, which may cause the tool bit to come off the object.

Therefore, when the control amount of the motor is switched to the final control amount after the lapse of the initial drive period, the control amount may be gradually changed to the final control amount so that the rotation speed of the motor gradually increases.

With this configuration, the rotation speed of the motor gradually increases, so that it is possible to prevent the tool bit from coming off the object by switching the control amount.
In addition, when an operation unit for setting the operation mode is provided, when changing the control amount of the motor to the final control amount, the change rate is different for each operation mode so that the rotation speed of the motor gradually increases. The control amount may be gradually changed to the final control amount.

In this case, when the operation mode is the low speed mode in which the motor rotates at a low speed, the control unit gradually changes the control amount to the final control amount as compared with the high speed mode in which the operation mode rotates the motor at a high speed. The rate of change of the control amount may be increased.

By doing this, when the operation mode is the low speed mode, the rotation state of the motor after the initial drive period has elapsed can be shifted to the target rotation state earlier, and in turn, the tightening of the object in the low speed mode can be achieved. It is possible to prevent the required time from increasing.

Conversely, when the operation mode is the low speed mode, the control unit has a smaller rate of change in the control amount when gradually changing the control amount to the final control amount than when the operation mode is the high speed mode. It may be configured as follows.

With this configuration, when the operation mode is the low speed mode, it becomes possible to slowly shift the rotation state of the motor after the lapse of the initial drive period to the target rotation state, and by changing the control amount in the low speed mode. It is possible to prevent the tool bit from coming off the object.

Next, when the control amount of the motor is gradually changed to the final control amount after the lapse of the initial drive period, the control unit changes the control amount at a constant rate of change (in other words, stepwise at a rate of a predetermined amount at a predetermined time. It may be changed.

In this case, the control unit sets the rate of change of the control amount after the lapse of the initial drive period to be smaller than the initial rate of change that is the rate of change of the control amount when increasing the rotation of the motor at the start of driving the motor. It may be configured.

In this way, the rate of change of the control amount after the lapse of the initial drive period is made smaller than the rate of change of the control amount at the start of driving the motor, and the control amount is slowly switched to the final control amount. You can Therefore, even in this case, it is possible to suppress the tool bit from coming off the object due to the switching of the control amount after the lapse of the initial drive period.

When the control amount of the motor is gradually changed to the final control amount after the initial drive period, the control unit changes the control amount so that the rate of change of the control amount gradually increases according to the elapsed time. May be.

With this configuration, the rotational speed of the motor increases in a bow after the initial drive period elapses, and immediately after the initial drive period elapses, the rotational increase of the motor is suppressed and the tool bit is prevented from coming off the object. Can be suppressed.

Further, since the rotation speed of the motor rises in a bow with the lapse of time from the initial drive period, it is possible to prevent the time required for tightening the object from becoming long.
Further, in this way, when the control amount is changed so that the rate of change gradually increases after the initial drive period elapses, the control unit sets the rate of change of the control amount to the initial rate of change immediately after the initial drive period elapses. It may be configured to be smaller than that.

Then, in this case, if the rate of change of the control amount becomes larger than the initial rate of change with the lapse of time after the lapse of the initial drive period, the tool bit is prevented from coming off the object after the lapse of the initial drive period. At the same time, it is possible to suppress an increase in the time required for tightening the object.

Next, the control unit controls the rotation state of the motor after the lapse of the initial drive period to the target rotation state by increasing the duty ratio of the PWM signal used for controlling the drive of the motor as the control amount of the motor. May be configured.

The control unit may be configured to control the rotation state of the motor after the lapse of the initial drive period to the target rotation state by widening the energization angle when driving the motor as the control amount of the motor.

Then, by controlling the rotation state of the motor after the lapse of the initial drive period to the target rotation state by widening the conduction angle, for example, the duty ratio of the PWM signal used for driving the motor is fixed to 100%, It suffices to control the start and end timings of energizing the coil.

In this case, compared to the case where the duty ratio of the PWM signal is controlled, it is not necessary to switch the switching element for energization control at high speed, so that heat generation of the switching element can be suppressed.

It is a longitudinal cross-sectional view of the rechargeable impact driver of the embodiment. It is a block diagram showing the electric constitution of the motor drive unit mounted in the rechargeable impact driver. 6 is a flowchart showing a control process executed by a control circuit. 4 is a flowchart showing a hit count process executed in S140 of FIG. 3. 4 is a flowchart showing a motor control process executed in S150 of FIG. 6 is a flowchart showing a motor drive process executed in S350 of FIG. 4 is a time chart showing changes in the control target, the rotation speed of the motor, and the current set by the motor control of the embodiment. 9 is a flowchart showing a motor drive process of modification 1. 9 is a time chart showing changes in control target, motor rotation speed, and current in Modification 1. 9 is a time chart showing changes in control target, motor rotation speed, and current in Modification 2. 9 is a flowchart showing a motor drive process of modification 2. 14 is a time chart illustrating an example of a procedure for setting a control target by motor control according to Modification 4. 9 is a time chart illustrating another example of a procedure for setting a control target by motor control according to Modification 4. 9 is a time chart showing changes in control target, motor rotation speed, and current in Modification 6. 13 is a flowchart showing a motor drive process of modification 6;

Embodiments of the present invention will be described below with reference to the drawings.
In this embodiment, a case where the present invention is applied to a rechargeable impact driver 1 which is an example of a rotary impact tool will be described.

As shown in FIG. 1, the rechargeable impact driver 1 of the present embodiment includes a tool body 10 and a battery pack 30 that supplies electric power to the tool body 10.
The tool body 10 is composed of a housing 2 in which a motor 4 and a striking mechanism 6 which will be described later are housed, and a grip portion 3 formed so as to project from a lower portion of the housing 2 (lower side in FIG. 1). ..

A motor 4 is housed in a rear portion (left side in FIG. 1) of the housing 2, and a bell-shaped hammer case 5 is assembled in front of the motor 4 (right side in FIG. 1). A striking mechanism 6 is housed in the case 5.

That is, a spindle 7 having a hollow portion formed on the rear end side is coaxially accommodated in the hammer case 5, and a ball bearing 8 provided on the rear end side in the hammer case 5 is mounted on the spindle 7. The outer circumference of the rear end is pivotally supported.

A planetary gear mechanism 9 composed of two planetary gears that are pivotally supported point-symmetrically with respect to the rotation axis is formed at the front portion of the ball bearing 8 in the spindle 7 on the inner peripheral surface of the rear end side of the hammer case 5. It meshes with the internal gear 11.

The planetary gear mechanism 9 meshes with a pinion 13 formed at the tip of the output shaft 12 of the motor 4.
The striking mechanism 6 includes a spindle 7, a hammer 14 mounted on the spindle 7, an anvil 15 pivotally supported on the front side of the hammer 14, and a coil spring 16 for biasing the hammer 14 forward. It

That is, the hammer 14 is connected to the spindle 7 so as to be integrally rotatable and movable in the axial direction, and is biased forward (on the anvil 15 side) by the coil spring 16.
The tip of the spindle 7 is rotatably supported by being coaxially inserted into the rear end of the anvil 15 so as to be rotatable.

The anvil 15 is rotated about an axis by receiving a rotational force and a striking force by the hammer 14, and is supported by a bearing 20 provided at the tip of the housing 2 so as to be rotatable about the axis and non-displaceable in the axial direction. ing.

A chuck sleeve 19 for mounting various tool bits (not shown) such as a driver bit and a socket bit is provided at the tip of the anvil 15.
The output shaft 12, the spindle 7, the hammer 14, the anvil 15 and the chuck sleeve 19 of the motor 4 are all arranged coaxially.

Further, on the front end surface of the hammer 14, two striking projections 17, 17 for giving striking force to the anvil 15 are provided so as to project at intervals of 180° in the circumferential direction.
On the other hand, on the rear end side of the anvil 15, there are formed two striking arms 18, 18 configured to be able to contact the striking protrusions 17, 17 of the hammer 14 at intervals of 180° in the circumferential direction. ing.

Then, the hammer 14 is biased and held toward the front end side of the spindle 7 by the biasing force of the coil spring 16, so that the impact projections 17 and 17 of the hammer 14 contact the impact arms 18 and 18 of the anvil 15. Like

In this state, when the spindle 7 is rotated by the rotational force of the motor 4 via the planetary gear mechanism 9, the hammer 14 rotates together with the spindle 7, and the rotational force of the hammer 14 causes the hammering protrusions 17, 17 and the striking arm 18, 18 is transmitted to the anvil 15.

As a result, the driver bit or the like mounted on the tip of the anvil 15 rotates, and the screw can be tightened.
When the torque is applied to the anvil 15 from the outside by tightening the screw to the predetermined position, the rotational force (torque) of the hammer 14 with respect to the anvil 15 also becomes the predetermined value or more.

As a result, the hammer 14 is displaced rearward against the biasing force of the coil spring 16, and the impact projections 17 and 17 of the hammer 14 pass over the impact arms 18 and 18 of the anvil 15. That is, the striking projections 17, 17 of the hammer 14 once disengage from the striking arms 18, 18 of the anvil 15 and run idly.

When the striking protrusions 17 and 17 of the hammer 14 get over the striking arms 18 and 18 of the anvil 15 in this way, the hammer 14 rotates forward together with the spindle 7 and is displaced forward by the biasing force of the coil spring 16. The striking projections 17, 17 of 14 strike the striking arms 18, 18 of the anvil 15 in the rotational direction.

Therefore, in the rechargeable impact driver 1 according to the present embodiment, the hammer 14 repeatedly hits the anvil 15 every time a torque of a predetermined value or more is applied to the anvil 15. Then, the striking force of the hammer 14 is intermittently applied to the anvil 15, whereby the screw can be tightened with a high torque.

Next, the grip portion 3 is a portion that the operator grips when using the rechargeable impact driver 1, and the trigger switch 21 is provided above the grip portion 3.
The trigger switch 21 is turned on/off by a trigger 21a pulled by an operator and the pulling operation of the trigger 21a, and the resistance value changes according to the operation amount (pulling amount) of the trigger 21a. The switch main body 21b is configured.

Further, on the upper side of the trigger switch 21 (the lower end side of the housing 2), the rotation direction of the motor 4 is the forward rotation direction (in the present embodiment, the clockwise direction when viewed from the rear end side of the tool) or the reverse rotation direction. A forward/reverse changeover switch 22 for switching to either one of the directions (the rotation direction opposite to the normal rotation direction) is provided.

In addition, an illumination LED 23 for irradiating the front of the rechargeable impact driver 1 with light when the trigger 21a is pulled is provided in front of the lower portion of the housing 2.
Further, a display panel 24 for displaying the operation mode (high speed/low speed) of the rechargeable impact driver 1, the remaining capacity of the battery 29, and the like is provided in the lower front portion of the grip portion 3.

A speed change switch 26 for setting the operation mode of the rechargeable impact driver 1 to the high speed mode or the low speed mode is provided near the display panel 24 (see FIG. 2).

Next, a battery pack 30 accommodating the battery 29 is detachably attached to the lower end of the grip portion 3. The battery pack 30 is mounted by being slid from the front side to the rear side of the lower end of the grip portion 3 at the time of mounting.

In the present embodiment, the battery 29 housed in the battery pack 30 is a rechargeable secondary battery such as a lithium ion battery.
Further, the motor 4 is a three-phase brushless motor including armature windings of U, V, and W phases in the present embodiment. The motor 4 is provided with a rotation sensor 50 (see FIG. 2) for detecting the rotation position (angle) of the motor 4.

The rotation sensor 50 includes, for example, three Hall elements arranged corresponding to each phase of the motor 4, and is a Hall IC or the like configured to generate a rotation detection signal for each predetermined rotation angle of the motor 4. Consists of

Further, inside the grip portion 3, a motor drive device 40 (see FIG. 2) that receives electric power from the battery pack 30 and drives and controls the motor 4 is provided.
As shown in FIG. 2, the motor drive device 40 is provided with a drive circuit 42, a gate circuit 44, a control circuit 46, and a regulator 48.

The drive circuit 42 is supplied with power from the battery 29 and supplies a current to each phase winding of the motor 4. In the present embodiment, the drive circuit 42 is a three-phase full bridge circuit including six switching elements Q1 to Q6. Is configured as. The switching elements Q1 to Q6 are MOSFETs in this embodiment.

In the drive circuit 42, the three switching elements Q1 to Q3 are provided as so-called high-side switches between the terminals U, V, W of the motor 4 and the power supply line connected to the positive side of the battery 29. There is.

The other three switching elements Q4 to Q6 are provided as so-called low-side switches between the terminals U, V, W of the motor 4 and the ground line connected to the negative side of the battery 29.

Further, the gate circuit 44 turns on/off each of the switching elements Q1 to Q6 in the drive circuit 42 in accordance with the control signal output from the control circuit 46, thereby causing a current to flow through each phase winding of the motor 4 and 4 is rotated.

Next, the control circuit 46 is composed of a microcomputer including a CPU, a ROM, a RAM and the like. The trigger switch 21 (specifically, the switch body 21b), the forward/reverse changeover switch 22, the illumination LED 23, the display panel 24, and the speed changeover switch 26 are connected to the control circuit 46.

Further, in the motor drive device 40, a current detection circuit 54 for detecting the current flowing in the motor 4 is provided in the energization path from the drive circuit 42 to the negative electrode side of the battery 29. The current detection circuit 54 includes, for example, a current detection resistor and an input circuit that inputs the voltage across the resistor to the control circuit 46 as a current detection signal.

Then, to the control circuit 46, the current detection signal from the current detection circuit 54 and the rotation detection signal from the rotation sensor 50 provided in the motor 4 are also input.
Next, when the trigger switch 21 is operated, the control circuit 46 obtains the rotation position and the rotation speed of the motor 4 based on the rotation detection signal from the rotation sensor 50 and follows the rotation direction setting signal from the forward/reverse changeover switch 22. , The motor 4 is driven in a predetermined rotation direction.

Further, when the motor 4 is driven, the control circuit 46 controls the speed command of the motor 4 according to the operation amount (pull amount) of the trigger switch 21 and the operation mode (high speed or low speed) set via the speed changeover switch 26. Set the value.

Then, the control circuit 46 sets the drive duty ratio of each of the switching elements Q1 to Q6 forming the drive circuit 42 according to the speed command value, and sends a control signal (PWM signal) corresponding to the drive duty ratio to the gate circuit 44. By outputting, the rotation speed of the motor 4 is controlled.

In addition to the drive control for driving the motor 4, the control circuit 46 also executes control for turning on the illumination LED 23 when the motor is driven.
Further, the regulator 48 receives power supply from the battery 29 and generates a constant power supply voltage Vcc (for example, 5 V DC) necessary to operate the control circuit 46. The control circuit 46 controls the regulator 48. It operates by being supplied with the power supply voltage Vcc from.

Next, the control processing executed by the control circuit 46 will be described.
As shown in FIG. 3, the control circuit 46 sets S120 to S at a predetermined control cycle (time base).
A series of processing of 160 (S represents a step) is repeatedly executed.

That is, the control circuit 46 waits for a predetermined control period to elapse by determining whether or not the time base has elapsed in S110, and when determining that the time base has elapsed in S110, proceeds to S120. Transition.

Then, in S120, by confirming the signal input from the trigger switch 21, the forward/reverse changeover switch 22, and the speed changeover switch 26, a switch operation detection process for detecting the operation of each of these switches is executed.

In subsequent S130, the operation amount (pull amount) of the trigger switch 21, the detection signals from the current detection circuit 54 and the rotation sensor 50, the battery voltage supplied from the battery pack 30, and the like are A/D converted and taken in A/ D conversion processing is executed.

Then, in subsequent S140, a hit count process is performed to detect the hit by the hit mechanism 6 and the number of hits (the hit count) from the change in the rotation speed of the motor 4 obtained from the detection signal from the rotation sensor 50.

Further, in subsequent S150, a motor control process for driving and controlling the motor 4 is executed based on the operation amount of the trigger switch 21, the operation mode set via the speed changeover switch 26, and the hit detection result by the hit count process. To do.

Finally, in S160, a display process for displaying the remaining capacity of the battery 29 on the display panel 24, lighting the illumination LED 23, and the like is executed in accordance with a command (operation setting) from the user, and the process proceeds to S110. ..

Next, the hit count processing executed in S140 will be described.
As shown in FIG. 4, when the hit count process is started, first, in S210, it is determined whether or not the trigger switch 21 is operated by the user to be in the ON state. Then, if the trigger switch is in the ON state, the process proceeds to S220, and it is determined whether or not to drive the motor 4 based on the operation amount of the trigger switch 21 and the like.

When it is determined in S220 that the motor 4 is not driven, or when it is determined in S210 that the trigger switch 21 is in the off state, the process proceeds to S295. Then, in S295, a time counter, a hit count flag, and a hit count determination flag, which will be described later, are each cleared, and the hit count process ends.

On the other hand, when it is determined in S220 that the motor 4 is to be driven, the process proceeds to S230, and it is determined whether or not the hit count flag is set. When it is determined in S230 that the hit count flag is not set (that is, cleared), the process proceeds to S240, and hit determination processing is executed.

In the hit determination process, the hit by the hit mechanism 6 is detected from the change in the rotation speed of the motor 4, and the number of times of detection (that is, the number of hits) is counted.
The hit detection in the hit determination processing can also be performed by detecting a change in the current detected by the current detection circuit 54. It can also be implemented by detecting the vibration generated by the impact with an acceleration sensor or the like.

When the hit determination process of S240 is completed, the process proceeds to S250, and it is determined whether or not the number of hits counted in the hit determination process is equal to or more than a specified number. If the number of hits is equal to or more than the specified number, the hit count flag is set in S260, and then the hit count process is ended. If the hit count is not equal to or more than the specified count, the hit count process is ended as it is. ..

Next, in S230, when it is determined that the hit count flag is set, the process proceeds to S270 to measure the drive time of the motor 4 after the hit count flag is set in S260. The time counter of is incremented (+1), and the process proceeds to S280.

In S280, based on the count value of the time counter, it is determined whether or not the elapsed time after the number of hits reaches the specified number of times is equal to or longer than a preset specified time, and the elapsed time is equal to or more than the specified time. For example, the process proceeds to S290, and the hit count determination flag is set.

Then, in S290, the hit count determination flag is set, or when it is determined in S280 that the elapsed time has not reached the specified time, the hit count processing is ended.
Next, the motor control process executed in S150 of FIG. 3 will be described.

As shown in FIG. 5, when the motor control process is started, first in S310, it is determined whether or not the trigger switch 21 is operated by the user to be in the ON state. Then, if the trigger switch is in the ON state, the process proceeds to S320, and it is determined whether to drive the motor 4 based on the operation amount of the trigger switch 21 and the like.

When it is determined in S320 that the motor 4 is not driven, or when it is determined in S310 that the trigger switch 21 is in the off state, the process proceeds to S400, and motor stop processing for stopping the motor 4 is executed. To do.

In this motor stop process, the braking force is generated in the motor 4 via the drive circuit 42, or the motor 4 is stopped by simply cutting off the energization to bring the motor 4 into the free-run state.

Then, in subsequent S410, a high-speed switching flag, which will be described later, and a drive duty ratio which is an output value (in other words, a control amount of the motor 4) for driving the motor 4 via the drive circuit 42 are cleared, The motor control process ends.

Next, when it is determined in S320 that the motor 4 is driven, the process proceeds to S330, and it is determined whether or not the operation mode set via the speed changeover switch 26 is the high speed mode.

When it is determined in S330 that the operation mode of the rechargeable impact driver 1 is not the high speed mode (that is, the low speed mode), the process proceeds to S340 to drive the motor 4 in the low speed mode. The low speed setting process for setting the low speed target value is executed, and the process proceeds to S350.

The low-speed target value is an output value (driving duty ratio) required to control the rotation speed of the motor 4 under no load to the set rotation speed N1 (see FIG. 7) according to the operation amount of the trigger switch 21. is there.

Then, in S340, a low speed target value (low speed target duty shown in FIG. 7) is set using a map or an arithmetic expression for the low speed mode in which the operation amount of the trigger switch 21 is used as a parameter.

Next, in S330, when it is determined that the operation mode of the rechargeable impact driver 1 is the high speed mode, the process proceeds to S360, and it is determined whether or not the high speed switching flag is set.

If it is determined in S360 that the high speed switching flag is not set, the process proceeds to S370 and it is determined whether or not the hit count determination flag is set.
If it is determined in S370 that the hit count determination flag is not set, the low speed setting process is executed in S340, and then the process proceeds to S350.

On the other hand, if it is determined in S360 that the high speed switching flag is set, or if it is determined in S370 that the hit count determination flag is set, the process proceeds to S380 and the motor 4 is driven at high speed. The high-speed setting process for setting the high-speed target value for driving in the mode is executed.

Then, in the following S390, the high speed switching flag is set, and the process proceeds to S350.
The high-speed target value set in S380 is an output value required to control the rotation speed of the motor 4 when there is no load to the set rotation speed N2 (see FIG. 7) according to the operation amount of the trigger switch 21. (Driving duty ratio).

Then, in S380, a high speed target value (high speed target duty shown in FIG. 7) is set using a map or an arithmetic expression for the high speed mode using the operation amount of the trigger switch 21 as a parameter.

Next, in S350, an output value, which is a control amount for actually controlling the motor 4, is set based on the low speed target value set in S340 or the high speed target value set in S380. Then, the motor drive process of generating a control signal based on the set output value and outputting the control signal to the gate circuit 44 is executed. After the motor drive processing of S350 is executed, the motor control processing is ended.

Next, the motor drive process will be described with reference to the flowchart shown in FIG.
As shown in FIG. 6, in the motor control process, first in S510, it is determined whether or not the high speed switching flag is set.

If the high-speed switching flag is not set, the step time counter described later is cleared in S520, and then the output value (drive duty ratio) used for drive control of the motor 4 is changed to the current output value in S530. It is updated by adding a predetermined addition value A to, and the process proceeds to S540.

In S540, it is determined whether or not the output value exceeds the low speed target value. If the output value exceeds the low speed target value, the output value is set to the low speed target value in S550, and then the motor drive processing is performed. finish. If the output value does not exceed the low speed target value, the motor driving process is ended as it is.

Note that this output value is a control signal output process separately performed by the control circuit 46 to generate a control signal (PWM signal) for PWM control of the power supplied to the motor 4 via the gate circuit 44. Used to do.

This output value is the drive duty ratio and is "zero" when the motor is stopped. Therefore, after the drive of the motor 4 is started, the process of S530 is repeatedly executed, so that the addition value from the initial value "zero" is added. It gradually increases at A and reaches the low speed target value (low speed target duty shown in FIG. 7).

Next, when it is determined in S510 that the high-speed switching flag is set, that is, the operation mode is the high-speed mode, the number of hits by the hitting mechanism 6 reaches the specified number, and then the specified time elapses. If the high speed target value is set in S380, the process proceeds to S560.

Then, in S560, it is determined whether or not the output value is the high-speed target value. If the output value is the high-speed target value, the motor drive processing is ended, and the output value is the high-speed target value. If not, the process proceeds to S570.

In S570, the step time counter is incremented (+1), and the process proceeds to S580. Then, in S580, it is determined whether or not the step time measured by the step time counter has reached the preset time, and if the step time has not reached the preset time, the motor drive processing is terminated. If the stage time has reached the set time, the process proceeds to S590.

In step S590, the step time counter is cleared, and the output value (driving duty ratio) is updated by adding a predetermined addition value B to the current output value. The added value B is set to be smaller than the added value A.

In subsequent S600, it is determined whether or not the output value exceeds the high-speed target value. If the output value exceeds the high-speed target value, the output value is set to the high-speed target value in S610, and then the motor is driven. The process ends. If the output value does not exceed the high speed target value, the motor driving process is ended as it is.

As described above, in the rechargeable impact driver 1 of the present embodiment, when the trigger switch 21 is operated to drive the motor 4, the output value (driving duty ratio) to the motor 4 is set to the low speed target. The value is gradually increased to the value (low speed target duty) (S530 to S550).

Therefore, as shown in FIG. 7, after the driving of the motor 4 is started (time t1), the rotation speed of the motor 4 gradually increases to the set rotation speed N1 and is maintained at the set rotation speed N1.
Therefore, when tightening the screw using the rechargeable impact driver 1 of the present embodiment, the rotation increase of the motor 4 immediately after the start of tightening is suppressed, the driver bit comes off the screw, and the screw head and the work material are damaged. Can be prevented.

Further, when the load starts to be applied to the motor 4 by the screw tightening (time point t2), the rotation speed of the motor 4 decreases, and then the striking by the striking mechanism 6 is started.
Then, when the operation mode is the low speed mode, the output value (driving duty ratio) to the motor 4 is held at the low speed target Duty, and the striking by the striking mechanism 6 is continued.

On the other hand, when the operation mode is the high-speed mode, the number of hits by the hitting mechanism 6 reaches the specified number of times, and when the specified time elapses thereafter (time point t3), the control target changes from the low-speed target value (low-speed target Duty). It is switched to the high speed target value (high speed target duty).

Then, when the control target is switched, the additional value B is added to the output value (driving duty ratio) every time the step time measured by the step time counter reaches the set time, and the output value (driving duty ratio) becomes The value gradually increases to the high speed target value (high speed target duty) (S560 to S610).

That is, when the operation mode is the high-speed mode, the initial drive period from the start of the driving of the motor 4 until the specified number of hits by the hitting mechanism 6 reaches the specified number of times, and the initial drive period elapses. After that, the drive power of the motor 4 is switched from low power to high power.

Therefore, in the high speed mode, the striking force by the striking mechanism 6 is suppressed more than usual during the initial driving period of the motor 4, and the striking by the striking mechanism 6 is prevented when the screw does not sufficiently enter the work material. Once started, the driver bit can be prevented from unscrewing.

Further, in the high speed mode, when the initial drive period elapses, the control target of the motor 4 is switched to the high speed target value (high speed target duty) which is the final control amount, and the striking force by the striking mechanism 6 becomes strong. The time required to tighten the work piece can be shortened.

Further, in the high speed mode, when the drive duty ratio, which is the output value, is switched from the low speed target Duty to the high speed target Duty, the drive duty ratio is increased stepwise, so that the rotation of the motor 4 rapidly increases due to the switching of the output value. It can also be prevented.

In particular, in the present embodiment, the additional value B used to increase the drive duty ratio from the low speed target Duty to the high speed target Duty increases the drive duty ratio from the initial value “0” when the drive is stopped to the low speed target Duty. It is smaller than the addition value A used for.

Therefore, according to the present embodiment, the increase rate of the target duty when increasing the drive duty ratio from the low-speed target duty to the high-speed target duty is the increase rate immediately after the start of driving the motor 4 (in other words, the initial change rate). ), the increase in rotation of the motor 4 can be suppressed more than at the start of driving the motor 4.

Therefore, according to this embodiment, even with this configuration, it is possible to prevent the driver bit from coming off the screw after the striking mechanism 6 starts striking.
In the present embodiment, the speed changeover switch 26 corresponds to the operating section of the present invention. The control circuit 46 corresponds to the batting detection unit and the control unit of the present invention. In particular, the batting frequency process executed by the control circuit 46 functions as the batting detection unit of the present invention. The executed motor control process functions as the control unit of the present invention.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modes can be adopted within the scope not departing from the gist of the present invention.
(Modification 1)
For example, in the above-described embodiment, when the output value, which is the control amount of the motor 4, is switched in the high speed mode, the drive duty ratio of the motor 4 is switched from the low speed target Duty to the high speed target Duty.

On the other hand, even if the energization angle at the time of driving the motor 4 is changed as the control amount of the motor 4 instead of the drive duty ratio of the PWM signal, the same effect as in the above embodiment can be obtained. Then, for this purpose, the motor drive processing may be executed in the procedure shown in FIG.

In this motor driving process, the drive duty ratio of the motor 4 is set to 100% when the operation amount of the trigger switch 21 is the maximum operation amount, and the target duty is set according to the operation amount of the trigger switch 21. Is used.

Therefore, in the motor drive process of FIG. 8, the output value is set to the advance value that is the timing of starting energization of each phase winding when driving the motor 4, and the energization angle that is the energization period. To do.

As shown in FIG. 8, in this motor control process, first in S710, it is determined whether or not the high speed switching flag is set. If the high speed switching flag is not set, in S720, the step time counter and Clear the energization angle switching flag.

Then, in the following S730, the advance value used for drive control of the motor 4 is updated by adding a predetermined addition value X to the current advance value, and the process proceeds to S740.
In S740, it is determined whether or not the advance angle value exceeds the low speed target value (for example, 22.5°). If the advance angle value exceeds the low speed target value, in S750, the advance angle value is set to the low speed target value. After setting the value, the motor driving process is ended. If the advance angle value does not exceed the low speed target value, the motor driving process is ended as it is.

The initial value of the advance angle value is a value smaller than the low speed target value (for example, zero). Therefore, by the process of S730, the advance value at the time of driving the motor 4 is gradually increased, the energization start timing to the motor 4 is moved to the advance side, and the drive power of the motor 4 (the drive torque is extended). Will increase.

Next, in S710, when it is determined that the high speed switching flag is set, the process proceeds to S760 and it is determined whether or not the advance value is the high speed target value (for example, 37.5°). If it is determined that the advance angle value is not the high speed target value, the process proceeds to S770. If the advance value is the high-speed target value, the process proceeds to S820.

In S770, the step time counter is incremented (+1), and the process proceeds to S780. Then, in S780, it is determined whether or not the stage time counted by the stage time counter has reached a preset time, and if the stage time does not reach the preset time, the motor drive process is terminated, If the step time has reached the set time, the process proceeds to S790.

In step S790, the step time counter is cleared, and the advance value is updated by adding the predetermined addition value Y to the current advance value, and the process proceeds to step S800.
Then, in S800, it is determined whether or not the advance angle value exceeds the high speed target value. If the advance angle value exceeds the high speed target value, in S810, after setting the advance angle value to the high speed target value, The motor drive process ends. If the advance angle value does not exceed the high speed target value, the motor driving process is ended as it is.

Next, in S820, it is determined whether or not the energization angle switching flag is set. Then, if the energization angle switching flag is set, the motor driving process is directly terminated, and if the energization angle switching flag is not set (that is, cleared), the process proceeds to S830.

In step S830, the step time counter is incremented (+1), and in step S840, it is determined whether the step time counted by the step time counter has reached a preset time. The set time may be the same as or different from the set time used for the determination in S780.

Then, in S840, when it is determined that the step time does not reach the set time, the motor drive processing is ended, and when it is determined that the step time reaches the set time, the process proceeds to S850 to drive the motor 4. Enlarge the conduction angle at time.

That is, in S850, the energization end timing for each phase winding is set to a predetermined angle (for example, 150°) so that the energization angle during motor driving becomes a high-speed target value (for example, 150°) wider than the low-speed target value (for example, 120°). 15°).

Then, in subsequent S860, the step time counter is cleared, the energization angle switching flag is set, and the motor driving process is ended.
As described above, in the motor drive process shown in FIG. 8, after the drive of the motor 4 is started (time point t1), the advance value when the motor 4 is driven is set to the low-speed target value (low-speed target advance value) as shown in FIG. The rotational speed of the motor 4 is increased up to the set rotational speed N1 (S720 to S750).

Then, when the load starts to be applied to the motor 4 by the screw tightening (time point t2), the rotation speed of the motor 4 decreases, and then the striking by the striking mechanism 6 is started. The angle value is held at the low speed target advance value, and the energization angle to the motor 4 is also fixed to the predetermined low speed target value.

On the other hand, when the operation mode is the high-speed mode, the number of hits by the hitting mechanism 6 reaches the specified number of times, and when the specified time elapses thereafter (time point t3), the control target of the advance angle value is set to the low-speed target advance value. To the high-speed target advance value.

Then, when the control target of the advance angle value is switched, the additional value Y is added to the advance angle value each time the step time measured by the step time counter reaches the set time, and the advance angle value is changed to the high-speed target advance value. The value gradually increases to the angular value (S770 to S810).

That is, when the operation mode is the high speed mode, when the number of hits by the hitting mechanism 6 reaches the specified number of times and the specified time elapses after the driving of the motor 4 is started, the advance value at the time of driving the motor 4 becomes low. The advance angle value is corrected to the advance angle side in the mode, and the energization angle to the motor 4 gradually increases.

Therefore, in the high speed mode, the striking force by the striking mechanism 6 is suppressed to the same extent as in the low speed mode during the initial drive period of the motor 4, and the first modification can also obtain the same effect as that of the above embodiment. it can.

Further, in the high speed mode, as shown in FIG. 9, when the advance angle value reaches the high speed target advance angle value (time point t4), the energization angle becomes the high speed target value (for example, 150°) after the elapse of a predetermined set time. As described above, the end timing of energization to each phase winding is delayed by a predetermined angle (S830 to S860).

As a result, according to the first modification, in the high speed mode, the rotation speed of the motor 4 is further increased due to the switching of the energization angle, and the time required to tighten the screw on the work material can be further shortened.

In Modification 1, if the operation amount of the trigger switch 21 is the maximum operation amount, the drive duty ratio of the motor 4 can be set to 100%. Therefore, when the drive duty ratio of the motor 4 is controlled. Compared with the above, heat generation of the switching element in the drive circuit 42 can be suppressed.
(Modification 2)
Next, in the above-described embodiment and modification, the control amount is added when switching the control amount (drive duty ratio or advance value) to the final control amount (high speed target duty or high speed target advance value) in the high speed mode. The value is gradually changed at a constant change rate determined by the value B or Y.

However, when switching the control amount to the final control amount in this way, as illustrated in FIG. 10, even if the rate of change (increase rate) of the control amount is changed so as to gradually increase according to the elapsed time. Good.

That is, in FIG. 10, in the rechargeable impact driver 1 of the embodiment, when the operation mode is the high speed mode, the initial drive period has elapsed, and the control target of the motor 4 is switched to the high speed target Duty, the drive duty ratio is arched. To change (increase).

Specifically, the increase rate of the drive duty ratio after the lapse of the initial drive period (after the time t3) is smaller than the increase rate immediately after the start of driving the motor 4 immediately after the lapse of the initial drive period, and then gradually increases. Is increased, and is finally higher than the increase rate immediately after the start of driving the motor 4.

In this way, if the drive duty ratio is increased in a bow to the high-speed target duty after the initial drive period has elapsed, it is possible to suppress an increase in rotation of the motor 4 immediately after the initial drive period has elapsed.

In particular, in the time chart shown in FIG. 10, since the increase rate of the drive duty ratio immediately after the initial drive period has elapsed is smaller than the increase rate immediately after the start of driving the motor 4, it is possible to prevent the rotation of the motor 4 from rapidly increasing. It can be suppressed better.

Therefore, according to the second modification, it is possible to more reliably prevent the driver bit from coming off the screw after the start of impact.
Further, since the rotational speed of the motor increases in a bow with the lapse of time from the initial drive period, it is possible to prevent the time required for tightening the screw from increasing.

Then, in order to change the drive duty ratio in a bowed manner after the initial drive period has elapsed, the motor drive process shown in FIG. 6 may be changed as shown in FIG. Hereinafter, this change will be described.

In the motor drive process shown in FIG. 11, after it is determined in S510 that the high speed switching flag is set, it is determined in S560 that the output value has reached the high speed target value, or in S570, the step time. The processing of S582 and S584 is executed until it is determined that has reached the set time.

In S582, the switching time counter that is cleared together with the step time counter in S520 is updated (+1) to measure the elapsed time from when the high speed switching flag is set until the output value reaches the high speed target value.

In subsequent S584, the additional value B is set based on the count value of the switching time counter (that is, the elapsed time after the end of the initial drive period). The process of S584 is a process for changing the output value in a bowed manner by setting the addition value B to be a large value according to the elapsed time after the end of the initial drive period. For, an arithmetic expression using the count value of the switching time counter as a parameter or a map is used.

Then, when the additional value B is set in S580, the process proceeds to S590, and the output value is updated by adding the set additional value B to the output value, and the processes of S600 and subsequent steps are executed.
Therefore, after the lapse of the initial drive period, the drive duty ratio of the motor 4, which is the output value, increases in a bow shape as shown in FIG. 10, and the above effect can be exhibited.
(Modification 3)
Next, in the above-described embodiment and modification, the number of hits by the hitting mechanism 6 is the specified number of times during the initial drive period after the drive of the motor 4 is started until the control target of the drive duty ratio is switched from the low speed target Duty to the high speed target Duty. After that, the period until the predetermined set time elapses.

However, the initial driving period may be defined only by the number of times of striking by the striking mechanism 6, or may be defined only by the elapsed time after the start of driving the motor 4.
(Modification 4)
Next, in the above-described embodiments and modified examples, it has been described that the control amount (driving duty ratio or advance value) is not switched in the low speed mode.

This is because in the low speed mode, the final target drive duty ratio or advance angle value is low, and even if the motor 4 is drive-controlled by this control amount, it is considered that the driver bit does not come off from the screw when a hit occurs. Is.

However, even in the low speed mode, the driver bit may be disengaged from the screw when a hit occurs. Therefore, in such a case, the drive duty ratio may be switched as in the high speed mode.

Further, in the above-described embodiment and modification, the rechargeable impact driver 1 capable of switching the operation mode between the low speed and the high speed via the speed changeover switch 26 has been described. However, the present invention can be applied in the same manner as the above-described embodiment even with a rechargeable impact driver capable of switching the operation mode to three stages of low speed, medium speed, and high speed, or more.

When the operation mode can be switched in three stages, the drive duty ratio can be switched between the low speed mode and the medium speed mode as in the high speed mode, as illustrated in FIG. 12 or FIG. .

When switching the drive duty ratio between a plurality of operation modes in this way, the motor control process (see FIG. 5) for each operation mode is executed for each operation mode, and the initial drive period and after the initial drive period elapses. The control amount (driving duty ratio or energization angle) may be switched depending on the final driving period.

Further, in this case, as is apparent from the enlarged view shown in FIG. 12, when the control amount is changed to the final control amount after the initial drive period has elapsed, for example, different addition values B and Y are set for each operation mode. Therefore, the rate of change of the control amount may be set for each operation mode.

In the enlarged view of FIG. 12, the change rate of the drive duty ratio (inclination in the increasing direction) when the drive duty ratio is changed to the final target duty is larger in the low speed mode than in the high speed mode. The high-speed mode may be larger. That is, the difference in the rate of change may be appropriately set according to the characteristics of the motor (in other words, the tool) to be controlled.

Further, FIG. 13 shows that, as described in the second modification, the rate of change of the control amount is increased with the passage of time to change the control amount in a bow, but in this case, the added value is changed according to the elapsed time. A map used to set B and the added value Y may be prepared for each operation mode.
(Modification 5)
Further, in the above-described embodiments and modifications, the control amount (driving duty ratio or conduction angle) of the motor 4 is always switched when the operation mode is the high speed mode.

However, this switching need not always be executed, and for example, whether switching control similar to that in the above-described embodiment is executed, or whether control is executed with the final control amount in the high speed mode without executing switching control. , May be selected by the user.

And if it does in this way, it becomes possible to further improve the usability of the rechargeable impact driver 1.
(Modification 6)
Next, in the above-described embodiment and modification, the control circuit 46 sets the control amount (driving duty ratio or energization angle) of the motor 4 based on the speed command value set according to the operation mode (high speed or low speed). Described as a thing.

However, the control circuit 46 sets the target rotation speed of the motor 4 according to the operation mode (high speed or low speed), and when driving the motor 4, drives the motor 4 so that the rotation speed of the motor 4 becomes the target rotation speed. It may be configured to control.

For example, as shown in FIG. 14, target rotation speeds NT1 and NT2 are set according to the operation mode (low speed mode, high speed mode), and the rotation speed of the motor 4 becomes the set target rotation speeds NT1 and NT2. Thus, the motor 4 is feedback-controlled.

Also in this modified example 6, as in the above-described embodiment, in the high speed mode, the motor 4 is drive-controlled at the target rotation speed NT1 in the low speed mode during the initial drive period from time t1 to t3, and the initial drive period elapses. After that, the target rotation speed may be switched to the target rotation speed NT2.

Note that, in FIG. 14, when the target rotation speed is switched as the initial drive period elapses, the drive duty ratio, which is the control amount, is gradually increased (more specifically, until the rotation speed of the motor 4 reaches the target rotation speed NT2). Similar to the second modification, it represents a change in a bow shape.

When controlling the rotation speed of the motor 4 in this way, the target rotation speed NT1 is set as the target rotation state of the motor 4 in S340 of the motor control process shown in FIG. The target rotation speed NT2 may be set as the target rotation state of No. 4.

Further, in this case, the motor drive processing of S350 may be performed in the procedure shown in FIG. The motor drive process of FIG. 15 will be described below.
In the motor driving process of FIG. 15, when it is determined in S510 that the high speed switching flag is not set, the step time counter and the switching time counter are set in the same manner as the motor driving process shown in FIG. To clear.

In subsequent S522, it is determined whether or not the rotation speed command to the motor 4 is lower than the target rotation speed NT1. If the rotation speed command is lower than the target rotation speed NT1, the process proceeds to S532, and the rotation speed command The rotation speed command is updated by adding the addition value A to.

Then, when the rotation speed command is updated in S532 or when it is determined in S522 that the rotation speed command has reached the target rotation speed NT1, the process proceeds to S620.
On the other hand, if the high speed switching flag is set, it is determined in S562 whether the rotation speed command is lower than the target rotation speed NT2.

When the rotation speed command is smaller than the target rotation speed NT2, the step time counter is incremented (+1) in S570, and the step time measured by the step time counter in S580 is the set time. To judge.

If it is determined in S562 that the rotation speed command has reached the target rotation speed NT2, or if it is determined in S580 that the stage time has not reached the set time, the process proceeds to S620.

When it is determined in S580 that the step time has reached the set time, the switching time counter is updated (+1) in S582, and the switching time is updated in S584, as in the motor driving process shown in FIG. The additional value B is set based on the count value of the counter.

Then, in step S592, the step time counter is cleared, and in subsequent step S594, the rotation speed command is updated by adding the additional value B to the rotation speed command, and the process proceeds to step S620.
In S620, the output value (drive duty ratio) is updated (increased or decreased) based on the speed difference between the rotation speed of the motor 4 and the rotation speed command, and the motor drive processing ends.

As a result, the rotation speed of the motor 4 is controlled to the target rotation speed NT1 or NT2.
Although the embodiment and the modified example of the present invention have been described above, the present invention is not limited to the rechargeable impact driver 1 and includes, for example, a rotary striking mechanism including a striking mechanism driven by a motor such as an impact wrench. Any tool can be applied.

Further, in the above-described embodiment, the motor 4 has been described as being configured by a three-phase brushless motor, but any motor capable of rotationally driving the striking mechanism 6 may be used. That is, for example, the rotary impact tool of the present invention is not limited to a battery type tool, but may be applied to one that receives power supply via a cord, or is configured to rotate and drive a tool element by an AC motor. It may be

1... Rechargeable impact driver, 2... Housing, 3... Grip part, 4... Motor, 5... Hammer case, 6... Strike mechanism, 7... Spindle, 8... Ball bearing, 9... Planetary gear mechanism, 10... Tool body, 11... Internal gear, 12... Output shaft, 13... Pinion, 14... Hammer, 15... Anvil, 16... Coil spring, 17... Strike projection, 18... Strike arm, 19... Chuck sleeve, 20... Bearing, 21... Trigger Switch, 22... forward/reverse changeover switch, 23... illumination LED, 24... display panel, 26... speed changeover switch, 29... battery, 30... battery pack, 40... motor drive device, 42... drive circuit, 44... gate circuit, 46... Control circuit, 48... Regulator, 50... Rotation sensor, 54... Current detection circuit.

Claims (13)

A motor,
A hammer that is rotated by the rotational force of the motor, an anvil that rotates by receiving the rotational force of the hammer, and a mounting portion for mounting a tool element on the anvil, and a predetermined value or more from the outside with respect to the anvil. When a torque is applied, the hammer is disengaged from the anvil and idles, and a striking mechanism that strikes the anvil in a rotation direction,
A hit detection unit that detects the hit of the anvil by the hammer,
A control unit that drives and controls the motor so that the motor is in a target rotation state;
Equipped with
The control unit is
Control of the motor so that the motor rotates at a lower speed than the target rotation state during an initial drive period from the start of driving the motor to the detection of the hit by the hit detection unit a predetermined number of times. When the amount is set and the initial drive period has elapsed, the control amount is switched to the final control amount corresponding to the target rotation state,
A rotary impact tool configured as follows. A motor,
A hammer that is rotated by the rotational force of the motor, an anvil that rotates by receiving the rotational force of the hammer, and a mounting portion for mounting a tool element on the anvil, and a predetermined value or more from the outside with respect to the anvil. When a torque is applied, the hammer is disengaged from the anvil and idles, and a striking mechanism that strikes the anvil in a rotation direction,
A hit detection unit that detects the hit of the anvil by the hammer,
A rotary impact tool having
An operation unit for selecting the operation mode of the rotary impact tool from a plurality of operation modes in which the target rotation state is different,
A control unit that drives and controls the motor so that a target rotation state corresponding to an operation mode set via the operation unit is achieved,
Equipped with
The control unit is
After the driving of the motor is started, the hit is detected by the hit detection unit, and further, the motor rotates at a speed lower than the target rotation state during an initial drive period until a predetermined period elapses. When the control amount of the motor is set so that the initial drive period elapses, the control amount is switched to the final control amount corresponding to the target rotation state,
When the operation mode set via the operation unit is a low speed mode in which the motor is rotated at a speed lower than the rotation speed in other operation modes, control corresponding to the target rotation state in the low speed mode The amount of driving of the motor is started, and the control amount is not switched after the driving of the motor is started.
A rotary impact tool configured as follows. The control unit is
When the control amount of the motor is switched to the final control amount after the initial drive period has elapsed, the control amount is gradually changed to the final control amount so that the rotation speed of the motor gradually increases.
The rotary impact tool according to claim 2, which is configured as described above. A motor,
A hammer that is rotated by the rotational force of the motor, an anvil that rotates by receiving the rotational force of the hammer, and a mounting portion for mounting a tool element on the anvil, and a predetermined value or more from the outside with respect to the anvil. When a torque is applied, the hammer is disengaged from the anvil and idles, and a striking mechanism that strikes the anvil in a rotation direction,
A hit detection unit that detects the hit of the anvil by the hammer,
A rotary impact tool having
An operation unit for selecting the operation mode of the rotary impact tool from a plurality of operation modes in which the target rotation state is different,
A control unit that drives and controls the motor so that a target rotation state corresponding to an operation mode set via the operation unit is achieved,
Equipped with
The control unit is
After the driving of the motor is started, the hit is detected by the hit detection unit, and further, the motor rotates at a speed lower than the target rotation state during an initial drive period until a predetermined period elapses. When the control amount of the motor is set so that the initial drive period elapses, the control amount is switched to the final control amount corresponding to the target rotation state,
When the control amount of the motor is switched to the final control amount after the lapse of the initial drive period, the control amount is changed to the final control amount at a different change rate for each operation mode so that the rotation speed of the motor gradually increases. Gradually change to the control amount,
A rotary impact tool configured as follows. The control unit is
When the operation mode is a low speed mode in which the motor is rotated at a low speed, when the operation amount is gradually changed to the final control amount as compared with a high speed mode in which the motor is rotated at a high speed, The control amount of the motor is set so that the rate of change of the control amount increases.
The rotary impact tool according to claim 4, which is configured as described above. The control unit is
When the operation mode is in a low speed mode for rotating the motor at a low speed, when the operation amount is gradually changed to the final control amount as compared with the high speed mode in which the motor is rotated at a high speed, The control amount of the motor is set so that the rate of change of the control amount becomes small.
The rotary impact tool according to claim 4, which is configured as described above. A motor,
A hammer that is rotated by the rotational force of the motor, an anvil that rotates by receiving the rotational force of the hammer, and a mounting portion for mounting a tool element on the anvil, and a predetermined value or more from the outside with respect to the anvil. When a torque is applied, the hammer is disengaged from the anvil and idles, and a striking mechanism that strikes the anvil in a rotation direction,
A hit detection unit that detects the hit of the anvil by the hammer,
A control unit that drives and controls the motor so that the motor is in a target rotation state;
Equipped with
The control unit is
After the driving of the motor is started, the hit is detected by the hit detection unit, and further, the motor rotates at a speed lower than the target rotation state during an initial drive period until a predetermined period elapses. When the control amount of the motor is set so that the initial drive period elapses, the control amount is switched to the final control amount corresponding to the target rotation state,
When switching the control amount of the motor to the final control amount after the lapse of the initial drive period, it is necessary to increase the rotation of the motor at the start of driving the motor so that the rotation speed of the motor gradually increases. The control amount is gradually changed to the final control amount at a constant change rate smaller than the initial change rate which is the change rate of the control amount,
A rotary impact tool configured as follows. A motor,
A hammer that is rotated by the rotational force of the motor, an anvil that rotates by receiving the rotational force of the hammer, and a mounting portion for mounting a tool element on the anvil, and a predetermined value or more from the outside with respect to the anvil. When a torque is applied, the hammer is disengaged from the anvil and idles, and a striking mechanism that strikes the anvil in a rotation direction,
A hit detection unit that detects the hit of the anvil by the hammer,
A control unit that drives and controls the motor so that the motor is in a target rotation state;
Equipped with
The control unit is
After the driving of the motor is started, the hit is detected by the hit detection unit, and further, the motor rotates at a speed lower than the target rotation state during an initial drive period until a predetermined period elapses. When the control amount of the motor is set so that the initial drive period elapses, the control amount is switched to the final control amount corresponding to the target rotation state,
When switching the control amount of the motor to the final control amount after the lapse of the initial drive period, immediately after the lapse of the initial drive period, at the start of driving of the motor so that the rotation speed of the motor gradually increases. The rate of change of the controlled variable becomes smaller than the initial rate of change that is the rate of change of the controlled variable when the rotation of the motor is increased, and the rate of change of the controlled variable becomes the initial rate with the passage of time thereafter. The control amount of the motor is gradually changed to the final control amount so as to be larger than the rate of change,
A rotary impact tool configured as follows. The control unit is
After the driving of the motor is started, when the hit is detected a predetermined number of times by the hit detection unit, it is determined that the initial drive period has elapsed, and the control amount of the motor is switched to the final control amount.
The rotary impact tool according to any one of claims 2 to 8, which is configured as described above. The control unit is
After the drive of the motor is started, when a preset time elapses after the impact is detected by the impact detector, it is determined that the initial drive period has elapsed, and the control amount of the motor is set to the final value. Switch to controlled variable,
The rotary impact tool according to any one of claims 2 to 8, which is configured as described above. A speed detector for detecting the rotation speed of the motor,
The control unit is
Rotation control is performed to set the control amount so that the rotation speed detected by the speed detection unit becomes the target rotation speed, and the switching of the control amount of the motor after the lapse of the initial drive period is performed by the target rotation speed. By switching,
The rotary impact tool according to any one of claims 1 to 10, which is configured as described above. The control unit is
As the control amount of the motor, by increasing the duty ratio of the PWM signal used to drive and control the motor, the rotation state of the motor after the lapse of the initial drive period is controlled to the target rotation state,
The rotary impact tool according to any one of claims 1 to 11, which is configured as described above. The control unit is
As the control amount of the motor, the energization angle at the time of driving the motor is widened to control the rotation state of the motor after the lapse of the initial drive period to the target rotation state,
The rotary impact tool according to any one of claims 1 to 11, which is configured as described above.