JP6943276B2 - tool - Google Patents

Description

The present invention relates to a tool.

In a general power tool, the user controls the rotation speed of the motor by pulling a trigger provided on the grip. The trigger includes a stroke type trigger that controls by the amount of operation, a load type trigger that controls by the magnitude of the operation load, and the like. Load sensors include those using semiconductors, strain gauges, and pressure-sensitive conductive elastoma (hereinafter referred to as pressure-sensitive rubber). For example, Patent Document 1 describes high electrical resistance in a non-pressurized / non-deformable state. A pressure-sensitive conductive elastoma showing a value and showing conductivity as the electric resistance value decreases as the load during compressive deformation increases is described.

Japanese Patent No. 4630964

However, the power tool that employs the load sensor described in Patent Document 1 and the like has the following problems. That is, the mechanical strength of the load sensor may change or deteriorate (sag). Since the hardness of rubber decreases as the temperature rises and increases as the temperature decreases, the characteristics of the resistance value with respect to the load become insensitive in a low temperature environment, and the rotation speed of the motor does not increase even when a load is applied. Due to such characteristics of the sensor, there is a problem that the output is not stable with respect to the load corresponding to the pressing operation of the user, and the workability is lowered.

Therefore, an object of the present invention is to provide a tool capable of stabilizing the output with respect to a load in order to solve the above-mentioned problems.

The tool according to the present invention is a tool including a switch for operating an electric component, and the switch applies a load corresponding to a switch operating unit for operating the switch and a pressing force due to the operation of the switch operating unit. comprising a load sensor for detecting a temperature measuring unit, a control unit for correcting the output for load detected by the load sensor based on the temperature of the load sensor measured by the temperature measuring unit, the load sensor The temperature measuring unit is housed inside the sensor accommodating member, and the sensor accommodating member is movably arranged in the load direction to operate the electric component based on the output corrected by the control unit. It is a thing.

According to the present invention, a stable output can be obtained without being affected by the characteristics of the load sensor.

It is a top view which shows the structural example of the power tool which concerns on one Embodiment of this invention. It is sectional drawing which shows the structural example of a power tool. It is sectional drawing which shows the structural example of a switch. It is sectional drawing which shows the structural example of a switch. It is sectional drawing which shows the structural example of the load sensor. It is sectional drawing which shows the operation example of a switch. It is a block diagram which shows the functional structure example of a power tool. It is a graph which shows the load-resistance value characteristic before and after deterioration of a load sensor. It is a flowchart which shows the operation example of the power tool when the deterioration of a load sensor is considered. It is a flowchart which shows the operation example of the power tool when the temperature change is taken into consideration.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[Structure example of power tool 10]
FIG. 1 shows an example of a planar configuration of the power tool 10 according to an embodiment of the present invention, and FIG. 2 shows an example of a cross-sectional configuration thereof. In FIGS. 1 and 2, the left side of the paper surface is the front side of the power tool 10, and the right side of the paper surface is the rear side of the power tool 10.

The power tool 10 according to the present invention is an impact driver using a DC brushless motor (hereinafter referred to as a motor 20) as a drive source. As shown in FIGS. 1 and 2, the power tool 10 includes a cylindrical power tool main body (housing) 12 and a grip 16 extending substantially vertically from the lower part of the power tool main body 12. A forward / reverse changeover switch 60 for switching the rotation of the motor 20 between forward rotation and reverse rotation is provided on the side surface portion of the power tool main body 12.

The power tool main body 12 contains a motor 20, a cooling fan 22, a speed reducer 40, a spindle 42, a hammer 44, and an anvil 46, respectively. The motor 20 is composed of, for example, a DC brushless motor, and is provided at the rear portion of the power tool main body 12. The motor 20 disclosed in the present invention is an example of an electric component.

The cooling fan 22 is provided behind the motor 20 and coaxially with the rotation shaft 20a of the motor 20. The cooling fan 22 rotates as the motor 20 rotates, sucks outside air from a suction port provided on the side surface of the power tool body 12, cools the motor 20, and sucks the sucked air into the side surface of the power tool body 12. It is discharged to the outside through the exhaust hole provided in.

The speed reducer 40 is provided in front of the motor 20 and is connected to the rotating shaft 20a of the motor 20. The speed reducer 40 constitutes a planetary gear mechanism and rotates with the rotation of the motor 20 to decelerate the rotation of the motor 20 and transmit the power of the motor 20 to the spindle 42.

The hammer 44 converts the rotation of the spindle 42 into a rotational striking force, and transmits the converted rotational striking force to the anvil 46. Specifically, when an external torque (screw tightening resistance) equal to or greater than the set torque is applied to the output shaft 46a described later during the screw tightening operation (when the motor 20 is started), the hammer 44 compresses the compression spring 45. By retreating, the engagement between the anvil 46 and the hammer 44 in the rotational direction is temporarily disengaged, and then the hammer 44 advances with the force that the compression spring 45 restores, and the hammer 44 moves the anvil 46 in the rotational direction. Hit.

The anvil 46 is provided at the tip of the power tool main body 12 and has an output shaft 46a to which a driver bit (tip tool) (not shown) can be mounted. When the motor 20 is rotationally driven with the driver bit attached to the output shaft 46a, the driver bit is rotated and hit by the driving force of the motor 20.

The grip 16 is a portion for gripping the power tool 10. At the lower part of the grip 16, a battery pack mounting portion 18 to which the battery 70 can be detachably mounted is provided. 1 and 2 show a state in which the battery 70 is attached to the battery pack attachment portion 18. The battery 70 is provided with a remaining battery level gauge so that the remaining battery level can be visually recognized.

An operation panel 24 is provided on the upper surface of the portion protruding in front of the battery pack mounting portion 18. The operation panel 24 has a mode setting button and the like for switching the striking mode.

The switch 30 is provided on the upper front side of the grip 16 at a position where the index finger rests when the user grips the grip 16. The amount of rotation of the motor 20 can be controlled according to the pressing operation (pulling operation) of the switch 30 by the user.

[Configuration example of switch 30]
3 and 4 show an example of the configuration of the switch 30. As shown in FIGS. 3 and 4, the switch 30 includes a trigger 300, a sensor unit 310, a fixing member 350, a temperature sensor (temperature measuring unit) 80, and a regulating unit 370, 372, 380. ..

The trigger 300 is a member for the user to turn on / off the electric tool 10 and adjust the rotation amount of the motor 20, and has a curved front side so that the user can easily press it with a finger. A protruding portion 300a projecting toward the sensor unit 310 is provided on the rear surface (back surface) of the trigger 300. The protrusion 300a moves to the sensor unit 310 side in response to the pressing operation of the trigger 300 by the user and presses the load sensor 320 described later. Further, a coil spring 362 is inserted between the trigger 300 and the load sensor cover member 330 described later, and the trigger 300 is urged on the side opposite to the pressing direction R.

The sensor unit 310 includes a load sensor 320, a load sensor cover member 330, and a load sensor support member 340. FIG. 5 shows an example of the cross-sectional configuration of the load sensor 320. As shown in FIG. 5, the load sensor 320 has a sealing cover 322, a pressure-sensitive conductive elastic member 324, and a substrate 326.

The sealing cover 322 is made of, for example, a soft resin material that can be elastically bent and deformed, and has a pressing portion 322a and a sealing portion 322b integrally formed therein. Each of the front surface side and the rear surface side of the pressing portion 322a protrudes in a hemispherical shape (dome shape), and the protruding portion on the front surface side elastically moves back and forth when pressed by the trigger 300, and the protruding portion on the rear surface side. Presses the pressure-sensitive conductive elastic member 324. The pressing portion 322a is provided so as to be separated from the protruding portion 300a of the trigger 300 by a distance D1 in order to prevent a malfunction (see FIG. 4). The seal portion 322b is provided so as to surround the entire circumference of the outer edge portion of the substrate 326, and has a function of ensuring waterproofness in the load sensor 320.

The pressure-sensitive conductive elastic member (movable contact) 324 is arranged between the sealing cover 322 and the substrate 326, and is composed of a plate-shaped conductive member that is elastically flexible and deformable. As the conductive member, for example, in addition to the metallic conductive member, a pressure-sensitive conductor member whose electric conductivity changes according to pressure, for example, conductive fine particles such as carbon, metal powder, and metal vapor deposition powder are contained in the rubber material. The pressure-sensitive member dispersed in the above can be preferably used. The pressure-sensitive conductive elastic member 324 comes into contact with the substrate 326 by bending due to the pressing force received from the sealing cover 322. In the present embodiment, the pressure-sensitive conductive elastic member (movable contact) 324 and the sealing cover 322 are in contact with each other, but they may be separated from each other.

The substrate 326 is made of a material such as a glass epoxy plate, and is arranged at a certain distance D2 from the pressure-sensitive conductive elastic member 324. A plurality of conductor patterns (not shown) forming fixed contacts are formed on the front surface side of the substrate 326. In the substrate 326, when the pressure-sensitive conductive elastic member 324 is compressed from the state of being in contact with the conductive pattern, the resistance value changes according to the compressive load (deformation amount) and becomes conductive, and the wiring connected to the substrate 326. An electric signal based on continuity is output to a control device 50 described later via 360. When the amount of deformation of the pressure-sensitive conductive elastic member 324 increases due to the increase in load, the resistance value decreases. As a result, it is possible to detect the resistance value against the load according to the pressing force of the trigger 300 by the user.

Returning to FIGS. 3 and 4, the load sensor cover member 330 covers the load sensor 320 to ensure the airtightness and waterproofness of the load sensor 320. The load sensor cover member 330 is composed of a cylindrical portion 332 and a flange portion 334 integrally formed therein. The cylindrical portion 332 enables the pressing portion 322a to be pressed by the protruding portion 300a by exposing the pressing portion 322a. The flange portion 334 is provided so as to project outward from the outer edge of the cylindrical portion 332 and cover the entire circumference of the outer edge portion of the sealing cover 322.

The load sensor support member 340 is a member for supporting the load sensor 320, and has a cylindrical portion 342 and a flange portion 344 integrally formed therein. The cylindrical portion 342 is a cylindrical member having a stepped portion, and is composed of a large-diameter cylindrical portion 342a and a small-diameter cylindrical portion 342b connected to the large-diameter cylindrical portion 342a. The flange portion 344 projects from the front outer edge of the large-diameter cylindrical portion 342a, and is in contact with the flange portion 334 of the load sensor cover member 330 and the seal portion 322b (see FIG. 5) of the sealing cover 322.

The flange portion 334 of the load sensor cover member 330 and the flange portion 344 of the load sensor support member 340 are fastened with screws 366 and 368 with the seal portion 322b of the sealing cover 322 sandwiched between them. As a result, the load sensor 320 becomes an integrated unit structure (sensor unit 310) included in the load sensor cover member 330 and the load sensor support member 340, and the airtightness and waterproofness of the load sensor 320 are ensured.

The fixing member 350 is fixed to a mounting portion (not shown) provided in the power tool main body 12, and restricts the movement of the trigger 300 and the sensor unit 310 in the pressing direction R. The fixing member 350 has a guide portion 350a for guiding the movement of the sensor unit 310. The guide portion 350a is provided on the inner peripheral surface of the fixing member 350, and is in contact with the outer peripheral surface of the cylindrical portion 342 to enable the sensor unit 310 to move in the linear pressing direction R. A spring 364 is inserted between the outer peripheral surface of the small-diameter cylindrical portion 342b of the load sensor support member 340 and the inner peripheral surface of the fixing member 350, and the sensor unit 310 is elastically supported by the coil spring 364. ..

The coil spring 364 is arranged coaxially with the load sensor 320, and elastically deforms when a load of a certain value or more is applied to the load sensor 320 by pressing the trigger 300 of the user. As a result, the sensor unit 310 can be configured to be movable with respect to the fixing member 350, and the pressing force received by the trigger 300 can be accurately transmitted to the load sensor 320, so that the sensitivity of the load sensor 320 can be increased. Can be improved. The coil spring 364 disclosed in the present invention is an example of an elastic member.

The temperature sensor 80 is composed of, for example, a thermistor, and is provided on the rear surface (back surface) side of the substrate 326 constituting the load sensor 320. The temperature sensor 80 is not limited to measuring the temperature of the load sensor 320, and may measure the ambient temperature in the used state after the power tool 10 is turned on. The ambient temperature includes, for example, the ambient temperature of the load sensor 320 in the power tool body 12, the ambient temperature around the power tool body 12, and the like. In this case, it is preferable to appropriately change the location where the temperature sensor 80 is attached.

As shown in FIG. 4, the regulating units 370 and 372 are provided at the upper and lower portions inside the switch 30, and regulate the moving distance of the trigger 300 by the user's pressure to be less than the maximum moving distance of the sensor unit 310. Is.

The regulating portion 370 is composed of a protruding portion 302 provided on the trigger 300 and an elongated hole 352 provided on the fixing member 350 extending in the pressing direction R of the trigger 300. The projecting portion 302 is a columnar member projecting from the inner surface side of the trigger 300 to the fixing member 350 side, and is slidably engaged with the elongated hole 352. The moving distance (stroke) D3 of the protruding portion 302 of the trigger 300 in the elongated hole 352 is less than the maximum moving distance (stroke) of the sensor unit 310 in the pressing direction R.

Since the regulation unit 372 has the same configuration as the regulation unit 370, detailed description thereof will be omitted. The regulating portion 372 is composed of a protruding portion 304 and an elongated hole 354. The protrusion 304 is slidably engaged with the elongated hole 354. The moving distance D4 of the protruding portion 304 of the trigger 300 in the elongated hole 354 is less than the maximum moving distance of the sensor unit 310 in the pressing direction R. The moving distance D3 is equal to the moving distance D4.

The regulation unit 380 is provided at the rear portion of the switch 30 to prevent the sensor unit 310 from coming off the coil spring 364 and regulate the movement amount of the sensor unit 310. The regulating portion 380 is composed of a protruding portion 356 provided on the fixing member 350 and a hook portion 342c provided on the load sensor support member 340.

The hook portion 342c has a recessed portion that is recessed downward, and is integrally formed at the rear end portion of the load sensor support member 340. The projecting portion 356 is a columnar member projecting from the inner surface side of the fixing member 350 toward the load sensor support member 340 side, and is movably engaged with the hook portion 342c. The moving distance D5 of the protruding portion 356 in the hook portion 342c is set to a length that allows the sensor unit 310 to move even if the stroke of the trigger 300 reaches the limit.

[Operation example of switch 30]
Next, an example of the operation of the switch 30 will be described with reference to FIGS. 3 to 6. FIG. 6 shows an example of the operation when the switch 30 is pulled. Before the trigger 300 is pressed by the user, the trigger 300 and the sealing cover 322 are separated by a distance D1, and the pressure-sensitive conductive elastic member 324 and the substrate 326 are separated by a distance D2. .. In this case, the load sensor 320 is in a non-conducting state. Further, before the trigger 300 is pressed, the sensor unit 310 is urged toward the trigger 300 by the coil spring 364, but the hook portion 342c is locked by the protruding portion 356. As a result, it is possible to prevent the sensor unit 310 from coming off from the fixing member 350.

When the trigger 300 is pressed by the user, the trigger 300 moves in the pressing direction R, and the protruding portion 300a of the trigger 300 comes into contact with the pressing portion 322a of the sealing cover 322 and presses the trigger 300. When the trigger 300 is further pressed, the pressing portion 322a of the sealing cover 322 presses the pressure-sensitive conductive elastic member 324. As a result, the pressure-sensitive conductive elastic member 324 elastically deforms and bends to come into contact with the substrate 326. That is, the trigger 300 (protruding portions 302, 304) moves in the pressing direction R by the amount of displacement allowed at the distances D1 and D2.

Further, when the trigger 300 is further pressed by the user and a load equal to or larger than the mounting load of the coil spring 364 is applied to the trigger 300, the coil spring 364 is compressed to include the load sensor 320, as shown in FIG. The unit 310 moves in the pressing direction R (rearward). When the sensor unit 310 moves by the distance D3, the movement of the trigger 300 including the protrusions 302 and 304 is restricted by the elongated holes 352 and 354. That is, the trigger 300 reaches the stroke limit before the stroke limit of the sensor unit 310. As a result, it is possible to prevent a load of 364 or more from the coil spring from being applied to the load sensor 320.

Further, even when the trigger 300 moves the maximum distance regulated by the regulating portions 370 and 372, the protruding portion 356 in the hook portion 324c is still in a state where it can be moved by the distance D6. That is, the sensor unit 310 is configured to be movable with a margin of a distance D6 with respect to the fixed member 350. As a result, damage to the load sensor 320 can be prevented even when an excessive load is applied to the load sensor 320.

[Example of block configuration of power tool 10]
FIG. 7 is a block diagram showing an example of the functional configuration of the power tool 10. As shown in FIG. 7, the power tool 10 includes a control device 50 for controlling the overall operation of the power tool 10. The control device 50 is a microcomputer (microcomputer) mainly composed of a CPU (Central Processing Unit) 52, a ROM (Read Only Memory) 54, and a RAM (Random Access Memory) 56. The control device 50 executes a correction operation for correcting an error due to deterioration of the switch 30 or the like, a drive control for the motor 20, or the like according to a program stored in advance in the ROM 54 or the like.

A load sensor 320, a temperature sensor 80, a forward / reverse changeover switch 60, a motor 20, a lighting device 62, an operation panel 24, a battery 70, and a storage unit 90 are connected to the control device 50, respectively. There is.

The load sensor 320 detects a load corresponding to the pressing force of the trigger 300 by the user, and supplies a detection signal based on the detection to the control device 50. The temperature sensor 80 detects the temperature (ambient temperature) of the load sensor 320 and supplies the temperature information to the control device 50. The forward / reverse changeover switch 60 supplies a changeover signal to the control device 50 based on a changeover operation of forward rotation or reverse rotation by the user.

The motor 20 is rotationally driven based on a drive signal supplied from the control device 50. The lighting device 62 is composed of, for example, a plurality of LEDs provided on the power tool main body 12, and is turned on or off based on a drive signal supplied from the control device 50. The operation panel 24 switches the display based on the instruction of the control device 50.

The battery 70 supplies electric power to each component such as the control device 50. The storage unit 90 is composed of, for example, a non-volatile semiconductor memory or the like, and has a load-resistance value characteristic indicating a load and a resistance value as a reference value, and a plurality of load-resistances indicating a load and a resistance value set for each temperature. Stores the table in which the value characteristics are stored. For example, as the temperature, the load-resistance value characteristic can be set for each of −10 ° C., 0 ° C., 25 ° C., 30 ° C., and 40 ° C. The load-resistance value characteristic may be set in advance as a functional expression, and the resistance value with respect to the load may be calculated by real-time calculation.

[Load-resistance characteristics]
The load sensor 320 has a problem that the output characteristics with respect to the load change due to deterioration or temperature change. FIG. 8 is a graph showing an example of the relationship between the load detected by the load sensor 320 and the resistance value. In FIG. 8, the solid line shows the load-resistance value characteristic (reference value) before deterioration of the load sensor 320, and the broken line shows the load-resistance value characteristic after deterioration of the load sensor 320. The vertical axis is the resistance value, and the horizontal axis is the load.

As shown in FIG. 8, in the load-resistance value characteristic before deterioration, the larger the load detected by the load sensor 320, the smaller the resistance value to the load. On the other hand, in the load-resistance value characteristic after deterioration, when the load detected by the load sensor 320 increases, the resistance value decreases, but the decrease in resistance value with respect to the load becomes insensitive compared to before deterioration, and before deterioration. The resistance value is larger than that. As a result, there is a problem that the rotation speed of the motor 20 increases with a small load, and it is not possible to obtain an accurate rotation speed of the motor 20 according to the load.

Therefore, in the present embodiment, the resistance value under a constant load is detected, the difference between the detected resistance value and the reference value is used as the correction value, and the resistance value for the load subsequently detected by the load sensor 320 is used as the correction value. By reflecting the above, the output error caused by the deterioration of the load sensor 320 and the like is corrected. Here, the constant load in the present embodiment means the maximum load that can be obtained via the coil spring 364 as the load adjusting mechanism.

For example, as shown in FIG. 8, when a constant load is 1000 (gf), the resistance value R1 when the load detected by the load sensor 320 reaches about 1000 (gf) is acquired. Subsequently, the difference C between the resistance value R2 as the reference value when the load is 1000 (gf) and the acquired resistance value R1 is calculated, and the difference C is corrected for the output error caused by deterioration or the like. And. Since the load-resistance value characteristic before deterioration and the load-resistance value characteristic after deterioration change with almost the same amount of deviation, the same correction value can be used for the resistance value under other loads. Of course, the calculated correction value may be further corrected for each detected load. The constant load can be arbitrarily set by the coil spring 364 or the like to be adopted, and is not limited to 1000 (gf) described above.

Here, it can be determined as follows whether the load applied to the load sensor 320 has reached a certain load. When a load equal to or greater than a predetermined load is applied to the power tool 10, the hammer 44 gives a rotary impact to the anvil 46 to tighten the screws. Since the impact generated by the impact is also transmitted to the load sensor 320, the load signal detected by the load sensor 320 fluctuates periodically. At this time, the more strongly the trigger 300 is gripped, the more stable the load sensor 320 is. Therefore, when the trigger 300 is gripped strongly, the fluctuation (amplitude) of the resistance value detected by the load sensor 320 becomes small, and when the grip of the trigger 300 is weak. The fluctuation (amplitude) of the resistance value becomes large. Therefore, in the present embodiment, attention is paid to the change in the amplitude of the resistance value that changes according to the holding force of the trigger 300, and when the amplitude of the resistance value becomes equal to or less than a preset threshold value, the load sensor 320 is used. It is judged that the given load has reached a certain load (maximum load).

[Operation example of power tool 10 (1)]
FIG. 9 is a flowchart showing an example of the correction operation of the power tool 10 when the deterioration of the load sensor 320 is taken into consideration. The correction operation of the power tool 10 shown below is realized by the control device 50 (CPU 52) executing the program stored in the ROM 54.

As shown in FIG. 9, in step S100, the control device 50 determines whether or not the trigger 300 has been operated by the user. When the control device 50 determines that the trigger 300 has not been operated by the user, the control device 50 waits until the user operates the trigger 300. On the other hand, when the control device 50 determines that the trigger 300 has been operated by the user, the control device 50 proceeds to step S110.

In step S110, the load sensor 320 detects the load corresponding to the pressing force of the user's trigger 300. The control device 50 calculates the resistance value with respect to the load detected by the load sensor 320. When step S110 is completed, the process proceeds to step S120.

In step S120, the control device 50 determines whether or not the amplitude of the calculated resistance value is equal to or less than a preset threshold value. That is, it is determined whether or not the load detected by the load sensor 320 has reached a certain load (maximum load). When the amplitude of the acquired resistance value is not less than or equal to the threshold value, that is, when the amplitude of the resistance value exceeds the threshold value, the control device 50 determines that the constant load has not been reached, returns to step S110, and returns to the resistance value. Continuously monitor the amplitude of. On the other hand, when the control device 50 determines that the amplitude of the acquired resistance value is equal to or less than the threshold value, the control device 50 proceeds to step S130.

In step S130, the control device 50 acquires the resistance value when a constant load is reached. That is, the resistance value when the maximum load is applied to the load sensor 320 by the pressing operation of the trigger 300 of the user is acquired. When step S130 is completed, the process proceeds to step S140.

In step S140, the control device 50 reads a preset reference value (load-resistance value characteristic) from the storage unit 90, and calculates a correction value based on a comparison result between the read reference value and the acquired resistance value. The reference value is, for example, a normal resistance value of the load sensor 320 acquired before the load sensor 320 is deteriorated (before shipment). When step S140 is completed, the process proceeds to step S150.

In step S150, the control device 50 corrects the resistance value (output) detected by the load sensor 320 in response to the subsequent pressing of the trigger 300 by the user, using the calculated correction value. By outputting a voltage signal based on the corrected resistance value to the motor 20, the control device 50 can realize a rotational drive of the motor 20 that is not affected by the deterioration of the load sensor 320.

[Operation example of power tool 10 (Part 2)]
FIG. 10 is a flowchart showing an example of the correction operation of the power tool 10 when the temperature change of the load sensor 320 is taken into consideration. This correction operation is performed, for example, when the load of the load sensor 320 does not reach a constant load, and when the work is performed at a site where the temperature is high and then moved to a site where the temperature is low. It can be suitably applied. Further, for example, in a season with a large temperature difference, it can be suitably applied to the case where the work is performed at night after the work is performed during the day.

The correction operation of the power tool 10 shown below is realized by the control device 50 (CPU 52) executing the program stored in the ROM 54. Specifically, in step S200, the control device 50 determines whether or not the trigger 300 has been operated by the user. When the control device 50 determines that the trigger 300 has not been operated by the user, the control device 50 continuously monitors the presence or absence of the user's operation. On the other hand, when the control device 50 determines that the trigger 300 has been operated by the user, the control device 50 proceeds to step S210.

In step S210, the temperature sensor 80 measures the temperature of the load sensor 320 as the control device 50 is activated. When step S210 is completed, the process proceeds to step S220.

In step S220, the control device 50 stores a plurality of load-resistance characteristics (reference values) as a reference corresponding to the temperature of the load sensor 320 measured by the temperature sensor 80 for each temperature. Select from the value characteristics and read. When step S220 is completed, the process proceeds to step S230.

In step S230, the control device 50 acquires a load corresponding to the pressing force of the user's trigger 300 operation from the load sensor 320, and calculates a resistance value with respect to the acquired load. For example, the first movement of the trigger 300 may be started, or the trigger 300 may be pulled without tightening the screws. When step S230 is completed, the process proceeds to step S240.

In step S240, the control device 50 acquires a reference resistance value associated with a load corresponding to the load corresponding to the pressing force of the user based on the load-resistance value characteristic read from the storage unit 90. When step S240 is completed, the process proceeds to step S250.

In step S250, the control device 50 calculates a correction value by comparing the resistance value with respect to the load corresponding to the pressing force of the user with the reference value of the resistance value acquired from the load-resistance value characteristic. When step S250 is completed, the process proceeds to step S260. The output value of the load sensor 320 may be compared with the reference value, and if the output is far from the reference value, it may be determined to be abnormal and notified. The notification means may be, for example, a voice or a buzzer sound, or may be a lighting display by an LED or the like. As a result, it is possible to grasp that an abnormality has occurred in the power tool 10.

In step S260, the control device 50 corrects the resistance value detected by the load sensor 320 in response to the pressing of the trigger 300 by the user, using the calculated correction value. The control device 50 can realize a rotational drive of the motor 20 that is not affected by the temperature change by outputting a voltage signal based on the corrected resistance value to the motor 20.

As described above, according to the present embodiment, the output is corrected based on the difference between the resistance value with respect to the detected load and the reference value, so that the load sensor 320 is deteriorated and the temperature changes under the usage environment. A stable operation feeling of the switch 30 can be obtained without being affected. For example, conventionally, when a rubber type load sensor 320 is used, the hardness of the rubber may change due to a temperature change, and the desired rotation of the motor 20 may not be obtained. According to this, since the load-resistance value characteristic is used as a reference for each environmental temperature and the correction is performed according to the temperature, highly accurate operation can be performed regardless of the temperature change.

Further, according to the present embodiment, for example, the correction operation shown in FIG. 10 is executed at the start of use of the power tool 10, and the correction operation shown in FIG. 9 is executed after the start of use of the power tool 10. Can be done. As a result, even when the load sensor 320 does not reach a constant load as in the case of starting to use the power tool 10, the resistance value against the load can be accurately corrected. As for the correction operations shown in FIGS. 9 and 10, only one of the correction operations may be incorporated into the power tool 10, or both correction operations may be incorporated into the power tool 10.

The technical scope of the present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, an example in which a pressure-sensitive rubber type load sensor is used as an example of the load sensor 320 has been described. However, in addition to this, the present invention can be used even when a semiconductor type load sensor or a strain gauge type load sensor is used. Can be applied.

Further, in the above-described embodiment, when the output correction in consideration of the temperature change is performed, the load-resistance value characteristic and the function formula are provided for each temperature, but the present invention is not limited to this. For example, it may have a plurality of load-resistance value characteristics (output characteristics) and functional expressions according to the user's preference. Specifically, it is conceivable to perform a correction operation corresponding to each of a user who wants to obtain a strong output by a light pulling operation and a user who wants to obtain a corresponding output by a heavy pulling operation.
Further, when performing detailed work, the sensitivity of the trigger 300 may be corrected to be more sensitive than in the normal state so as to improve the response of the power tool 10.
Furthermore, regardless of how the trigger 300 is pulled, the load-output is such as a correction that starts the rotation slowly at the beginning of pulling and enables a drive that gradually increases the rotation, and a correction that quickly reaches the maximum speed. The characteristics may be changed for each load range, and the upper limit of the output (rotation speed) is set so that a predetermined output can be obtained regardless of how the trigger 300 is pulled so that it can be easily used according to the work target. It is conceivable to make corrections such as providing. At that time, it is possible to select a characteristic according to the user's preference from a plurality of output characteristics stored in advance, and if an arbitrary load is stored, the usability can be further improved.

Further, in the above-described embodiment, the output under a constant load is corrected, but the present invention is not limited to this, and for example, at least one of the preset usage time and the number of operations of the power tool 10. When the above condition is satisfied, the output for the load detected by the load sensor 320 may be corrected. In this case, the correction value is preferably set in proportion to the usage time and the number of operations.

Further, in the regulating portions 370 and 372 of the above-described embodiment, the relationship between the protruding portions 302 and 304 and the elongated holes 352 and 354 can be reversed. Similarly, the protruding portion 356 of the regulating portion 380 and the hook portion 342c can be configured in reverse. Further, the method for determining whether the load applied to the load sensor 320 has reached a constant load is not limited to the above-described embodiment, and the displacement sensor is used to detect the maximum stroke of the trigger 300. You may.

10 Power tool 12 Power tool body 20 Motor (electric parts)
30 Switch 44 Hammer 46 Anvil 50 Control unit (control unit)
80 Temperature sensor (Temperature measuring unit)
300 trigger (switch operation unit)
310 Sensor unit (sensor accommodating member)
320 Load sensor 364 Coil spring (load adjustment mechanism)

Claims (5)

A tool equipped with a switch for operating electrical components.
The switch
A switch operation unit that operates the switch and
A load sensor that detects the load according to the pressing force by operating the switch operation unit, and
Temperature measuring unit and
A control unit that corrects the output for the load detected by the load sensor based on the temperature of the load sensor measured by the temperature measuring unit, and a control unit.
With
The load sensor and the temperature measuring unit are housed inside the sensor housing member, and the load sensor and the temperature measuring unit are housed inside the sensor housing member.
The sensor accommodating member is arranged so as to be movable in the load direction.
A tool for operating the electric component based on the output corrected by the control unit. The temperature measuring unit is provided on the back surface side of the substrate constituting the load sensor.
The tool according to claim 1. The tool according to claim 1 or 2, wherein the control unit corrects the output of the load sensor based on a comparison between the output of the load sensor and a reference value under a predetermined load. The tool according to claim 3, wherein the reference value for a load detected by the load sensor is provided for each temperature. The tool according to any one of claims 1 to 4, wherein the load sensor is a pressure-sensitive rubber type load sensor.

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