JP2008264905A - Power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power tool facilitating a normal position of a bit at the time of starting rotation of the bit, shortening a time to reach a sufficient number of revolution of the bit, and allowing a worker to easily judge that the number of revolution of the bit becomes sufficient. <P>SOLUTION: This power tool 1 has informing means 8 for informing a worker, and control means 9 for controlling a driving volume of drive means 4 rotary driving a bit 10 and controlling inform-processing of the informing means 8. The control means 9 changes a rotary condition of the bit 10 by changing the driving control volume of the drive means 4, and makes the informing means 8 execute informing process according to the change of the driving control volume. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric tool capable of performing a drilling operation of an object, a rotation driving operation of a fastening member, and the like by rotating a bit installed at a tool tip.

  Conventionally, a concrete drill or the like is known as a tool for making a hole in concrete or the like. Concrete rill has a structure in which a bit formed with a spiral groove is placed at the tip of a tool and a concrete wall or the like is excavated and drilled by rotating the bit at a high speed.

  However, if the bit is driven at high speed from the beginning, excessive force (torque) may be applied to the tip of the bit, so it is not easy to localize the bit at the desired drilling position. was there. Similarly, there is a problem that the tool may swing due to the reaction force of the starting torque, which may place a burden on the operator's hand.

  In order to solve such a problem, a soft start function has been proposed in which the rotational amount of the motor is gradually changed by gradually increasing the driving amount of the motor from the time of startup (see, for example, Patent Document 1). ).

  In this way, by performing the rotational drive control of the bit using the soft start function at the time of start-up, it becomes easy to align the drilling position and effectively suppress the tool from swinging due to the reaction force of the start-up torque. It becomes possible.

  On the other hand, when drilling a hole in a concrete wall with a concrete drill, the drilling time can be shortened by applying an excitation force to the tip of the bit as well as forming a drilling hole only by rotating the bit. An electric tool that can be realized has been proposed (see, for example, Patent Document 2).

By installing such a vibration device on a concrete drill or the like, it is possible to apply a pulsatingly changing pressure to a concrete wall or the like. It can be applied to the tip of the bit, so that it is possible to speed up the drilling work and reduce the work load.
JP 2001-103786 A Japanese Patent No. 3680941

  However, when the rotation of the bit is driven using the soft start function described above, the bit reaches a sufficient number of revolutions (which can exhibit the desired drilling capability) when the operator only visually recognizes the rotation state of the bit. There was a problem that it was not possible to determine easily.

  Further, when using a tool having a soft start function, there is a problem that the time until the bit reaches a sufficient number of revolutions becomes longer than that of the conventional tool. For this reason, when a tool with a soft start function is operated as if handling a conventional tool, aggressive drilling may start before the bit reaches a sufficient rotational speed. There was a problem of getting.

  On the other hand, even in a concrete drill with an oscillating device, when the oscillating device is driven from the beginning when the bit starts to rotate, a force that changes in a pulsating manner is applied to the tip of the bit. There are problems that it is difficult to localize the bit at the drilling position, or that the tool may change in a direction unintended by the operator due to reaction force.

  The present invention has been made in view of the above problems, and can easily localize the bit at the start of bit rotation, reduce the time until the bit reaches a sufficient number of rotations, It is an object of the present invention to provide an electric tool that enables a person to easily determine that the rotational speed of a bit has reached a sufficient rotational speed.

  In order to solve the above problems, an electric tool according to the present invention performs drive amount control of a notification means for notifying an operator and a drive means for rotating a bit, and a notification in the notification means. Control means for performing processing control, and the control means changes the rotation control state of the bit by changing the drive control amount of the drive means, and causes the notification means to execute notification processing according to the change of the drive control amount. It is characterized by that.

  In this way, the control means changes the drive control amount of the drive means, for example, when the drive means is started, the drive control is performed in a soft start state in which the increase amount of the drive control amount is moderated, and then the drive means is driven. It is possible to change to an acceleration startup state in which the increase amount of the control amount is accelerated. For this reason, since it can suppress that big starting torque generate | occur | produces with respect to a bit at the time of starting, position alignment (orientation) of the bit in a drilling position can be performed easily, and also by reaction force at the time of starting It is possible to prevent the tool from swung around.

  Furthermore, when changing the rotation state of the bit by changing the drive control amount of the drive means, the notification is performed according to the change of the drive control amount, so the operator changes the drive state of the control means. Thus, it can be easily determined that the rotational speed of the bit has been changed. Therefore, for example, since the notification means determines that the drive control state has changed from the soft start state to the acceleration start-up state as described above, full-scale work can be started. In consideration of the rapid rise of the bit, it becomes possible to start the work at the same time that the bit reaches the rotation state suitable for the work.

  In addition, since the work can be started at the same time when the bit reaches a sufficient rotation state, before the bit reaches a rotation speed suitable for the work (a target rotation speed at which the work can be effectively performed), Starting full-scale work can be prevented, and the work can be performed in a state where the ability of the electric power tool can be maximized.

  In addition, as a notification means, the means etc. which notify a worker by generation | occurrence | production of a vibration, the output of a sound, and also light emission, etc. can be used.

  Furthermore, the notification means of the electric tool described above may be a vibration generation means that notifies the operator of the execution of the notification means by vibration.

  When the notification means is the vibration generation means, the operator can feel the notification (vibration) by the notification means through the housing of the electric tool, so that, for example, noise at the work site using the electric tool is noisy. Even in cases, it is possible to reliably recognize the notification by the notification means.

  Furthermore, the vibration generating means may be a vibration device for applying a vibration force that pulsates in the direction of the tip of the bit while changing the magnitude.

  Some electric tools, such as concrete drills, include a vibration device for efficiently and effectively performing a drilling operation. For this reason, in such an electric tool, it is possible to perform notification using existing equipment without adding a new notification means by using the vibration exciter as the notification means.

  Further, as described above, notification is performed using the vibration of the vibration exciter, so that notification can be reliably performed even when the work site using the electric tool is noisy.

  Furthermore, if the excitation device is activated when performing bit alignment, etc., it becomes difficult to perform bit alignment. Therefore, after the bit alignment is completed, that is, after the soft start state is completed, By operating the device as a notification means, it is possible to suppress the operation of the vibration exciter during bit alignment.

  Further, the above-described electric power tool has time-lapse means for measuring an elapsed time after the bit starts to rotate, and the control means controls the drive control amount for the drive means according to the elapsed time measured by the time-lapse means. It may be characterized by changing.

  In this way, by changing the drive control amount for the drive means in accordance with the elapsed time since the rotation of the bit is started, it is possible to perform drive amount control according to the situation in which the power tool is used. Become. For example, when performing bit alignment (bit positioning at the drilling position) when driving an electric tool, soft start until the time (for example, 1 second) required for bit alignment (localization) has elapsed. By performing the drive control in the state, it is possible to perform the alignment operation reliably and easily. Furthermore, after that (for example, after 1 second has elapsed), the drive control amount is changed to the acceleration start-up state, thereby shortening the time until the bit reaches the full rotation state and maximizing the ability. It becomes possible to guide the electric tool to a possible driving state at an early stage.

  Further, the above-described electric tool has a rotation speed detection means for detecting the rotation speed of the bit, and the control means changes the drive control amount for the drive means according to the rotation speed detected by the rotation speed detection means. It may be characterized by.

Thus, by changing the drive control amount for the driving means in accordance with the rotation speed of the bit, it becomes possible to control the rotation speed of the bit so that the rotation speed is suitable for the situation where the electric tool is used. . For example, when the bit alignment is performed when the electric tool is driven, the bit is preferably rotated at a low rotation in order to perform the alignment smoothly. For this reason, when the rotation speed is less than or equal to the bit position suitable for bit alignment (for example, 4000 min ⁻¹ or less), the drive means is controlled in a soft start state that moderately increases the drive control amount, and the rotation speed is greater than the preferred rotation speed In this case, it is possible to shorten the time until the bit reaches a sufficient rotation state by changing the driving control amount of the driving means to an acceleration start-up state that increases the acceleration at an accelerated rate. Become.

  By using the power tool according to the present invention, it is possible to change the rotation state of the bit by changing the drive control amount of the driving means. Therefore, the localization of the bit can be controlled by suppressing the drive control amount at the start of the bit rotation. It becomes possible to carry out easily. In addition, by changing the drive control amount after the localization operation to rapidly increase the rotation state of the bit, it is possible to shorten the time until the bit reaches a sufficient number of rotations. Further, since the notification means can notify the operator when the rotation state of the bit changes, the worker can reach a sufficient number of rotations of the bit based on the notification from the notification means. This makes it possible to easily determine this, and it is possible to use the electric tool in a rotating state of the bit that can maximize its ability.

[Embodiment 1]
Hereinafter, an electric tool according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a concrete drill as an electric power tool according to Embodiment 1, and FIG. 2 is a cross-sectional view.

  The concrete drill 1 includes a main switch 3, a main motor (drive means) 4, a rotation drive transmission unit 5, a main motor rotation number detection unit (rotation number detection unit) 6, and a power assist motor 7 disposed in a housing 2. , A power assist mechanism (notification means, vibration generation means, excitation device) 8 and a control part (control means, time-elapsed means) 9 are schematically configured.

  The housing | casing 2 is formed with the resin-made casing members, and this casing member is comprised by a pair of halved casing which makes left-right symmetry. A grip portion 2a for holding the concrete drill 1 is formed at the rear end of the housing 2, and the main switch 3 is provided at a position where the finger can be easily turned on / off with the grip 2a. It has been.

  The main switch 3 is a switch for performing an on / off operation of electric power supplied from an external power source via a power cable base 2b formed at the lower end of the grip portion 2a. Thus, the main motor 4 and the power assist motor 7 can be driven.

  The main motor 4 is a motor for rotationally driving the bit 10 attached to the tool tip via the rotational drive transmission unit 5. The drive control of the main motor 4 is performed according to the on / off operation of the main switch 3, but the number of rotations of the main motor 4 can be changed stepwise in accordance with an instruction from the control unit 9.

  The main motor rotation speed detection unit 6 is installed at a position facing the rear end side surface of the rotation shaft 4 a of the main motor 4. Magnetic bodies 4b indicating N poles and S poles are alternately arranged along the outer periphery at the rear end of the rotating shaft 4a. The hall sensor 6a provided in the main motor rotation number detecting unit 6 causes the rotating shaft to rotate. By detecting the change of the SN pole accompanying the rotation of 4a, the number of rotations of the rotating shaft 4a in the main motor 4 is detected.

  The rotation drive transmission unit 5 has a role of transmitting the driving force of the rotation shaft 4 a of the main motor 4 to the bit 10. The rotation drive transmission unit 5 is provided with a rotation shaft portion 5a that rotates in conjunction with the rotation of the rotation shaft 4a of the main motor 4, and a bit 10 can be attached to the tip of the rotation shaft portion 5a. Yes. For this reason, the operator can select and attach the bit 10 suitable for the work object by operating the chuck 5b provided at the front end of the housing 2.

  The power assist motor 7 is a motor for driving a power assist mechanism unit 8 described below. The power assist motor 7 is a motor whose rotational output is smaller than that of the main motor 4, and is disposed so as to be positioned below the main motor 4. Similarly to the main motor 4, the power assist motor 7 is also driven and controlled according to the on / off operation of the main switch 3, but in the first embodiment, the main switch 3 is in an on state, When the drive operation control is performed according to the control unit 9, the power assist motor 7 is driven. The rotating shaft 7a of the power assist motor 7 is provided with a bevel gear 7b as shown in FIGS. The extending direction of the rotating shaft 7 a of the power assist motor 7 is directed in the forward direction of the concrete drill 1 in the same manner as the extending direction of the rotating shaft 4 a of the main motor 4 and rotates so as to be parallel to the bit 10. A shaft 7a is provided.

  The power assist mechanism unit 8 is a device for applying an excitation force in the front-rear direction of the tool in accordance with the driving of the power assist motor 7. The power assist mechanism 8 is composed of a pair of vibration members 12 and 13 that face each other. The vibration members 12 and 13 are bevel gears 12a and 13a meshing with the bevel gear 7b of the power assist motor 7, rotary shafts 12b and 13b rotated by the bevel gears 12a and 13a, and outer surfaces of the rotary shafts 12b and 13b. And the eccentric weight portions 12c and 13c attached so as to occupy the outer peripheral semicircular portion. The eccentric weight portions 12c and 13c have a predetermined weight, and rotate around the rotation shafts 12b and 13b in accordance with the rotation of the bevel gear 7b of the power assist motor 7 and travel in the centrifugal direction of the rotation shafts 12b and 13b. The structure is such that a force is generated with respect to the housing 2.

  As shown in FIGS. 3 (a) and 3 (b), the pair of vibrating members 12 and 13 includes an eccentric weight portion 12c (13c) of one vibrating member 12 (13) and a rotating shaft 12b (13b). ), The eccentric weight portion 13c (12c) of the other vibration member 13 (12) is positioned in the upper half periphery of the rotary shaft 13b (12b) The bevel gears 12 a and 13 a are meshed with the bevel gear 7 b of the power assist motor 7. For this reason, when the rotating shaft 7a of the power assist motor 7 is rotationally driven, one eccentric weight portion 12c (13c) generates an upward excitation force, and at the same time, the other eccentric weight portion. Since 13c (12c) generates a downward exciting force, the torsional moment in the direction of the arrow shown in FIGS. Are alternately applied in the left-right rotation direction.

  On the other hand, the rotating shaft 7a of the power assist motor 7 is rotationally driven, and the eccentric weight portion 12c (13c) provided on one vibration member 12 (13) is positioned at the front half-circumferential portion of the rotating shaft 12b (13b). In this case, as shown in FIG. 4A, the other eccentric weight portion 13c (12c) is also rotationally driven so as to be positioned in the front half circumference portion of the rotating shaft 13b (12c). As shown in (b), when one eccentric weight part 12c (13c) is located in the rear half circumference part of the rotating shaft 12b (13b), the other eccentric weight part 13c (12c) is also a rotating shaft. 13b (12c) is driven to rotate so as to be located in the rear half circumference portion.

  For this reason, when the rotating shaft 7a of the power assist motor 7 is driven to rotate, both the vibrating members 12 and 13 generate a vibrating force in the forward direction (the arrow direction in FIG. 4A) at the same timing. At the same time, an exciting force is generated in the rearward direction (in the direction of the arrow in FIG. 4B), so that the oscillating members 12 and 13 pulsate back and forth with respect to the housing 2 due to the rotation. An excitation force can be applied.

  In this way, by operating the power assist mechanism 8, it is possible to generate vibration in the front-rear direction with respect to the housing 2, so when the operator forms a perforation in a concrete wall or the like, the tip of the bit 10 Therefore, it is possible to effectively apply a pulsating pressure to the perforation forming speed.

  Further, since the rotational moment is alternately applied to the housing 2 in the left-right direction by the operation of the power assist mechanism 8, a twisting force can be applied to the tip of the bit 10. Thus, it is easy to reduce the burden of drilling work on the operator and increase the drilling speed.

  In the first embodiment, the power assist mechanism unit 8 is not used only for reducing the burden of the drilling work of the worker and improving the processing speed. It has a function as a notification means for indicating that the rotation state of the main motor 4 has been changed to the raised state. The details will be described in the description of the control process of the control unit 9 described later.

  The control unit 9 has a function of performing drive control of the main motor 4 and the power assist motor 7. As shown in FIG. 5, the control unit 9 includes a main switch detection function for detecting on / off of the main switch 3, a time-lapse function for measuring an elapsed time since the main switch 3 is turned on, and a main motor rotational speed. A main motor rotation speed detection function for detecting the rotation speed of the main motor 4 detected by the detector 6, a main motor control function for driving and controlling the main motor 4, and power assist for performing drive control of the power assist motor 7. It has a motor control function.

  The control unit 9 is an electronic circuit (control board) having a functional circuit for realizing these functions, and may be configured by a hardware that realizes the above functions. A central processing unit (ROM), a read only memory (ROM), a random access memory (RAM), and the like may be included, and a CPU or the like may realize the above processing by software processing according to a program recorded in the ROM. .

  The control unit 9 has a structure capable of detecting an operation signal in accordance with the on / off state of the main switch 3, and realizes a main switch detection function by detecting the operation signal. Further, the control unit 9 uses a hardware resource such as a clock generator or uses a sampling processing function or the like provided in the CPU in a software control so that an elapsed time after the main switch 3 is turned on is stored. Timekeeping can be performed, and this aging process realizes the aging function.

  Further, the control unit 9 can determine the number of rotations of the main motor 4 and thus the number of rotations of the bit 10 by acquiring information on the number of rotations of the main motor 4 detected by the main motor rotation number detection unit 6. The main motor rotational speed detection function is realized by this rotational speed determination process. Further, the control unit 9 can change the number of revolutions of the main motor 4 by adjusting the amount of power supplied to the main motor 4 and the like. The main motor control function is realized by the processing. Furthermore, the control unit 9 can perform on / off switching of the amount of electric power supplied to the power assist motor 7, and a power assist motor control function is realized by this on / off switching control.

  Next, drive control processing of the main motor 4 and the power assist mechanism unit 8 in the control unit 9 will be described in detail using a flowchart. FIG. 6 is a flowchart showing processing in the control unit 9.

  The control unit 9 detects an operation signal from the main switch 3 (step S.1), and determines whether or not the main switch is turned on (step S.2). When it is determined that the main switch 3 is not turned on (No in step S.2), the control unit 9 detects and determines the operation signal in the main switch 3 until the main switch 3 is turned on (step S.1, step S.2) are repeated.

If it is determined that the main switch 3 is turned on (Yes in step S.2), the control unit 9 drives the main motor 4 to rotate by soft start (step S.3). Here, the rotational drive of the main motor 4 by soft start means a drive method in which the rotational speed of the rotary shaft 4a in the main motor 4 is gradually increased by controlling the main motor 4. In this way, by controlling the drive of the main motor 4 by soft start, the bit 10 that is driven to rotate by the main motor 4 at the same time as the main switch 3 is turned on becomes the target rotational speed (the rotational speed of the bit suitable for the drilling operation). Etc.), for example, it is possible to avoid that it is difficult for the operator to perform alignment for drilling due to rising to 8000 min ⁻¹ (rpm), and it is effective that the tool swings due to the reaction force of the starting torque. Can be suppressed.

  Then, after starting the measurement (elapsed time) of the elapsed time after the main switch 3 is turned on (step S.4), the control unit 9 detects the elapsed time (step S.5), It is determined whether or not a predetermined time Δt, 1 second in the first embodiment, has elapsed (step S.6). If it is determined that 1 second has not elapsed since the main switch was turned on (No in step S.6), the control unit 9 detects the elapsed time again (step S.5), 1 second. It is repeatedly determined whether or not it has passed (step S.6).

  When it is determined that one second has elapsed since the main switch 3 was turned on (Yes in step S.6), the control unit 9 controls the drive state of the main motor 4 so that the rotational speed of the rotary shaft 4a is The control state of the main motor 4 is changed to an acceleration startup state that accelerates more rapidly than in the case of soft start (step S.7).

FIGS. 7A and 7B are diagrams showing changes in the rotational speed of the main motor 4 over time, and show a case where the target rotational speed is set to 8000 min ⁻¹ . FIG. 7A shows a case where the drive control of the main motor 4 is controlled using only soft start, and FIG. 7B shows the drive state of the main motor 4 one second after the main switch 3 is turned on. This shows a case where is changed to the acceleration start-up state in two stages.

When the main motor 4 is driven and controlled only by the soft start, as shown in FIG. 7A, it takes about 2 seconds until the rotational speed of the rotary shaft 4a reaches the target rotational speed of 8000 min ^−1. In contrast, when the acceleration is changed to the acceleration start state after 1 second, the rotational speed of the rotary shaft reaches 8000 min ⁻¹ in about 1.3 seconds as shown in FIG. 7B. Can be made. For this reason, the operator can start the drilling work earlier than the case where the drive control of the main motor 4 is performed only by the soft start, and the work operation can be speeded up.

  In addition, since the drive control in the soft start state is performed until 1 second elapses, the driving is started by turning on the main switch 3 after the bit 10 is aligned with the drilling position or the main switch 3 is turned on. When driving is started by performing alignment of the bit 10 at the same time or immediately afterward, it is possible to prevent a large starting torque from being generated when the rotation of the bit 10 is started. For this reason, it is easy to align the bit 10 at the drilling position, and it is possible to prevent the tool from swinging due to the reaction force of the starting torque at the time of starting, so that the drilling work can be performed reliably and easily. It becomes.

  Further, the control unit 9 changes the driving state of the main motor 4 to the acceleration start-up state, and simultaneously drives the power assist motor 7 to start driving the power assist mechanism unit 8 (step S.8).

In this way, by changing the driving state of the main motor 4 to the acceleration start-up state and simultaneously starting the driving of the power assist mechanism unit 8, the operator can reduce the vibration generated by the driving of the power assist mechanism unit 8. It can be experienced through the housing 2. The operator can easily determine that the driving state of the main motor 4 has changed from the soft start state to the acceleration start-up state based on the vibration start by the power assist mechanism 8 as a determination criterion. As soon as the rotation speed reaches the target rotation speed of 8000 min ⁻¹ , full-scale drilling work can be started.

In the concrete drill 1 shown in this Embodiment 1, as shown in FIG.7 (b), the drive state of the main motor 4 changes to an acceleration start-up state, and after 0.3 second, the rotation speed of the main motor 4 will change. The target rotational speed has reached 8000 min ⁻¹ . On the other hand, a normal worker usually needs about 0.3 to 0.5 seconds to start operating the tool after sensing the vibration by the power assist mechanism 8 with the brain. There is a tendency to. For this reason, even if the worker feels vibrations from the power assist mechanism 8 and at the same time starts aggressive drilling work, the rotational speed of the main motor 4 reaches the target rotational speed when the work is started. Thus, the operator can start work without considering the time until the rotational speed of the main motor 4 reaches the target rotational speed.

  Even when the operator feels the vibration of the power assist mechanism 8 and starts drilling work at the same time, the rotation speed of the main motor 4 has reached the target rotation speed as described above. The tool can be operated as if operating a conventional concrete drill 1 that does not have a start function.

  Further, even when the operator feels the vibration by the power assist mechanism 8 and starts the drilling operation at the same time, the rotational speed of the bit 10 is reached because the rotational speed of the main motor 4 has reached the target rotational speed. It is possible to prevent the aggressive drilling operation from starting before reaching the target rotational speed, and it is possible to perform the operation in a state where the drilling ability of the concrete drill 1 can be maximized. Become.

  Thereafter, the control unit 9 detects the rotation number of the main motor 4 from the main motor rotation number detection unit 6 (Step S.9), and based on the detected rotation number of the main motor 4, the rotation number of the main motor 4 is detected. Executes a drive control process of the main motor 4 so that the target rotational speed can be maintained (step S.10).

  The control unit 9 detects an operation signal from the main switch 3 (step S.11), and determines whether or not the main switch 3 is turned off (step S.12). When it is determined that the main switch 3 is not turned off (No in step S.12), the control unit 9 detects the number of rotations of the main motor 4 until the main switch 3 is turned off (step S.9). ), The drive control process of the main motor 4 (step S.10), and the operation signal detection / determination process (steps S.11 and S.12) in the main switch 3 are repeatedly executed.

  When it is determined that the main switch 3 is turned off (Yes in step S.12), the control unit 9 stops driving the main motor 4 (step S.13) and drives the power assist mechanism unit 8. Is stopped (step S.14), and the process is terminated.

  As described above, by using the concrete drill 1 according to the first embodiment, the driving state of the rotating shaft 4a in the main motor 4 can be rotationally driven by soft start, so that a large starting torque at the start of rotation of the bit 10 Can be prevented from occurring. For this reason, the bit 10 can be easily aligned at the drilling position, and the tool can be prevented from swinging due to the reaction force of the starting torque at the time of starting, so that the drilling operation can be performed reliably and easily. It becomes possible.

  In addition, after 1 second has passed since the main switch 3 was turned on, the drive state of the rotary shaft 4a is changed from the soft start state to the acceleration start-up state, so that the drive control of the main motor 4 is performed only by the soft start. As compared with the case of drilling, the drilling work can be started earlier, and the work operation can be speeded up.

  Further, since the driving state of the main motor 4 is changed to the acceleration start-up state and the driving of the power assist mechanism unit 8 is started at the same time, the driving state of the main motor 4 is accelerated by the driving of the power assist mechanism unit 8. It can be easily determined that the state has been changed to the raised state. For this reason, it is possible to start the work without considering the time until the bit 10 reaches the target rotational speed by starting the drilling work at the same time as experiencing the vibration by the power assist mechanism 8. The work can be started in a state where the drilling ability of the concrete drill 1 can be maximized.

  Further, even when the perforation forming operation is started at the same time as the vibration by the power assist mechanism unit 8 is sensed, the rotation speed of the main motor 4 has reached the target rotation speed, so that a conventional soft start function is not provided. The tool can be operated as if operating a concrete drill.

[Embodiment 2]
In the first embodiment described above, when a predetermined time (1 second in the first embodiment) has elapsed since the main switch 3 was turned on, the driving state of the main motor 4 is changed from the soft start to the acceleration start-up state. At the same time, the power assist mechanism unit 8 is operated to notify the operator that the soft start of the main motor 4 has been completed, but the driving state of the main motor 4 is changed from the soft start to the acceleration start-up state. The condition to be performed is not necessarily limited to the passage of the predetermined time. For example, it is possible to control the drive state of the main motor 4 to be changed according to the rotation speed of the main motor 4 detected by the main motor rotation speed detection unit 6.

  FIG. 8 is a flowchart showing a process of changing the driving state of the main motor 4 in accordance with the rotational speed of the main motor 4. FIG. 9A shows a change in the rotational speed of the main motor 4 in the process shown in FIG. FIG. The control unit 9 detects an operation signal from the main switch 3 (step S.1), and determines whether or not the main switch 3 is turned on (step S.2). If it is determined that the main switch 3 is turned on (Yes in step S.2), the control unit 9 drives the main motor 4 to rotate by soft start (step S.3).

Thereafter, the control unit 9 detects the rotation number of the main motor 4 from the main motor rotation number detection unit 6 (step S.5a), and whether the detected rotation number is a predetermined rotation number, for example, 4000 min ⁻¹ or more. It is determined whether or not (step S.6a). When the rotational speed is less than 4000 min ⁻¹ (in the case of No in step S.6a), the control unit 9 repeats the rotational speed detection process (step S.5a) until the rotational speed becomes 4000 min ⁻¹ or more. When the number is 4000 min ⁻¹ or more (Yes in step S.6a), the driving state of the main motor 4 is changed to the acceleration start-up state (step S.7).

  Thus, by changing the driving state of the main motor 4 according to the rotation speed of the main motor 4, it becomes possible to reliably change the driving state of the main motor 4 according to the increase in the rotation speed. Even when the drive state of the main motor 4 is changed according to the number of rotations of the main motor 4, as in the first embodiment, it is earlier than the case where the drive control of the main motor 4 is performed only by soft start. Thus, the drilling work can be started, and the work operation can be speeded up.

  Thereafter, the control unit 9 changes the driving state of the main motor 4 to the acceleration start-up state, and simultaneously starts driving the power assist mechanism unit 8 (step S.8), and detects the rotation speed of the main motor 4. Then, based on the detected rotation speed of the main motor 4, a drive control process for the main motor 4 is executed (step S.10). Then, the control unit 9 detects an operation signal from the main switch 3 (step S.11), and determines that the main switch 3 is turned off (Yes in step S.12), the main motor 4 And the drive of the power assist mechanism part 8 is stopped (step S.13, step S.14), and a process is complete | finished.

  As described above, even when the driving state of the main motor 4 is changed in accordance with the rotational speed of the main motor 4, the driving state of the main motor 4 is changed and at the same time, the driving of the power assist mechanism unit 8 is started. Thus, the drilling work can be started based on the sense of vibration by the power assist mechanism 8 as a judgment criterion, and the tool can be operated as if operating a conventional concrete drill that does not have a soft start function. .

  Further, even when the perforation forming operation is started at the same time as the vibration by the power assist mechanism unit 8 is sensed, the main motor 4 changes the driving state to the acceleration start-up state, so that the same as in the first embodiment. Since the rotation speed of the main motor 4 has reached the target rotation speed at the start of operation, the work can be started without considering the time until the bit 10 reaches the target rotation speed. The work can be started in a state where the drilling ability of the drill 1 can be maximized.

[Embodiment 3]
In the concrete drill 1 shown in the first embodiment, the case where the power assist mechanism unit 8 is used as a notification unit has been described. However, the notification unit is not necessarily limited to the power assist mechanism unit 8 alone. Some electric tools do not include the power assist mechanism 8, and therefore other informing means can be installed in such electric tools.

  For example, it is also possible to provide a configuration in which a lighting lamp or the like that can be visually recognized by an operator is provided in the housing 2 as a notification unit, and the lamp is turned on or off at the same time as the driving state of the main motor 4 is changed. . Even in the case where notification means that can be visually recognized is provided in this way, the operator can easily determine a change in the driving state of the main motor 4, so that the effects shown in the first embodiment can be obtained. Similar effects can be obtained.

  When a lamp or the like is provided as visual notification means, it is preferable to install the lamp or the like at a position that does not interfere with the work and is easily visible during the work, for example, on the upper surface of the housing. . Further, the lamp is not limited to a lamp that is turned on and off. Even if the lamp is always lit, a change in driving state can be easily determined as long as the color of light emitted from the lamp changes.

  Furthermore, the notification means is not limited to one that can be visually recognized. For example, a sound output mechanism such as a speaker that emits a specific sound (such as a BEEP sound) or a predetermined melody can be used as the notification means. In addition, it is preferable that the sound output from the sound output mechanism is a sound having a different sound range from a noise sound that can normally be generated in an environment in which the electric tool is used. By outputting a sound different from these noise sounds, it is possible to easily determine whether or not there is an output sound when using the power tool. For example, an artificial sound such as an electronic sound such as a BEEP sound is suitable.

[Embodiment 4]
In the first embodiment, the drive state of the main motor 4 is changed by the control unit 9 from the soft start state to the acceleration start-up state in two stages. The state change is not necessarily limited to two steps, and may be changed to multiple steps of three or more steps. For example, as shown in FIG. 9B, it is also possible to adopt a configuration in which the driving state is changed in three stages, 0.5 seconds after the main switch 3 is turned on and 1.0 seconds later. Thus, by changing the rotation state (driving state) of the bit in a multistage manner, it is possible to smoothly change a change in the starting torque applied to the bit 10. Further, even in the case of changing in multiple stages, it is possible for the operator to easily determine the driving state change by changing the light emission color of the lamp according to the stage, for example, by the notification means described above. Become.

  As mentioned above, although the concrete drill 1 provided with the electric tool which concerns on this invention was demonstrated in detail using drawing, the electric tool which concerns on this invention is not limited to the example shown in embodiment mentioned above. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention.

  For example, in the above-described embodiment, the concrete drill 1 is described as an example of the electric tool according to the present invention. However, the electric tool according to the present invention is not limited to the concrete drill 1 and is installed at the tool tip. As long as the electric tool has a structure for rotating the bit, a drill tool other than a concrete drill, a driver tool, and the like are also included in the electric tool of the present invention.

1 is an external perspective view showing a concrete drill according to Embodiment 1. FIG. 1 is a cross-sectional view showing a concrete drill according to Embodiment 1. FIG. FIG. 3 is a perspective view showing a schematic configuration of a power assist mechanism unit shown in the first embodiment. FIG. 6 is another perspective view showing a schematic configuration of the power assist mechanism section shown in the first embodiment. 3 is a block diagram illustrating a schematic configuration of a control unit illustrated in Embodiment 1. FIG. 3 is a flowchart showing processing contents of a control unit shown in the first embodiment. It is the figure which showed the rotation speed change of the main motor controlled according to the flowchart shown in FIG. 6 is a flowchart showing processing contents of a control unit shown in the second embodiment. (A) is the figure which showed the rotation speed change of the main motor controlled according to the flowchart shown in FIG. 8, (b) is the rotation speed change of the main motor controlled according to the processing content shown in Embodiment 4. FIG.

Explanation of symbols

1 ... Concrete drill (electric tool)
2 ... casing 2a ... gripping part 2b ... base 3 for power cable ... main switch 4 ... main motor (driving means)
4a ... Rotary shaft 4b (of the main motor) ... Magnetic body 5 ... Rotational drive transmission portion 5a ... Rotary shaft portion 5b (of rotational drive transmission portion) ... Chuck 6 ... Main motor rotational speed detection section (rotational speed detection means)
6a ... Hall sensor 7 ... Power assist motor 7a ... Rotating shaft 7b (of power assist motor) ... Bevel gear 8 (of power assist motor) ... Power assist mechanism (notifying means, vibration generating means, excitation device)
9: Control unit (control means, time-lapse means)
DESCRIPTION OF SYMBOLS 10 ... Bit 12, 13 ... Excitation member 12a, 13a ... Bevel gear wheel 12b, 13b (of the excitation member) ... Rotating shaft 12c, 13c (of the excitation member) ... Eccentric weight part

Claims (5)

An informing means for informing the worker;
Control means for controlling the driving amount of the driving means for rotationally driving the bit, and for performing notification processing control in the notification means,
The control means changes the rotation control state of the bit by changing the drive control amount of the drive means, and causes the notification means to execute notification processing according to the change of the drive control amount. tool. The power tool according to claim 1, wherein the notification unit is a vibration generation unit that notifies an operator of the execution of the notification unit by vibration. The power tool according to claim 2, wherein the vibration generating unit is a vibration device for applying a vibration force that pulsates in a tip direction of the bit while changing a size. A means for measuring time elapsed since the bit started to rotate;
The power tool according to any one of claims 1 to 3, wherein the control means changes a drive control amount for the drive means in accordance with an elapsed time elapsed by the time elapse means. A rotation number detecting means for detecting the rotation number of the bit;
The electric control according to any one of claims 1 to 4, wherein the control means changes a drive control amount for the drive means in accordance with the rotation speed detected by the rotation speed detection means. tool.

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