JP2013000863A - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent harmful influences of surge voltage or the like in an electric tool enabling a computer program and a control parameter for driving a motor to be changed from an external device.SOLUTION: The electric tool includes a motor for driving a tip tool, a control circuit board 9 for mounting a control circuit which controls rotation of the motor, and a communication connector 47b for removing/attaching a communication line that connects the control circuit and the external connection device. In the electric tool, the communication connector 47b is placed on a connector substrate 47a provided independently of the control circuit board 9, and electrostatic protection means 211 to 214 are provided on the connector board 47a. The electrostatic protection means 211 to 214 comprise varistors for connecting communication lines and ground lines. The varistors are formed into chip shapes and placed in such a way that a plurality of connection terminals 201 to 204 comprising the communication lines and a connection terminal 205 for ground are each connected.

Description

  The present invention relates to a power tool that can be connected to an external connection device via a communication cable, and more particularly to a power tool that can be effectively protected from static electricity generated when the communication cable is connected.

  In recent years, brushless DC motors have been widely used as drive sources for electric tools. The brushless DC motor is, for example, a DC (direct current) motor without a brush (rectifying brush), and is driven by an inverter circuit using a coil (winding) on the stator side and a magnet (permanent magnet) on the rotor side. The rotor is rotated by sequentially energizing the predetermined power to a predetermined coil. The inverter circuit is configured using a large-capacity output transistor such as an FET (Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor), and the inverter circuit is controlled by a microcomputer (hereinafter referred to as “microcomputer”). Controlled by running the program. A brushless DC motor is excellent in torque characteristics as compared with a brushed DC motor, and can tighten a screw, a bolt, or the like on a workpiece by a stronger force. Furthermore, since a microcomputer is used for motor rotation control, various control patterns can be realized by a program executed by the microcomputer.

  As an example of an impact tool using a brushless DC motor, for example, the technique of Patent Document 1 is known. In Patent Document 1, using a hammer and anvil that can relatively rotate less than 360 degrees, the motor is continuously rotated in the forward direction, or alternately rotated in the forward and reverse directions. Rotate the tool. In the technique of Patent Document 1, since the rotation of the motor is controlled by a microcomputer, the rotation of the motor can be controlled with high accuracy using a program.

JP 2011-62771 A

  For example, in an operation in a mass production assembly factory, a wide variety of screws and bolts are used, and thus electric tools having specifications suitable for each assembly site and parts used may be required. However, since the power tool control program is shipped from the factory in a state of being stored in advance in a non-volatile memory housed in the power tool, it is practically impossible to change the program after factory shipment. . As described above, in the conventional power tool, since the program written in the control unit (for example, the microcomputer) could not be substantially rewritten, a power tool that can immediately respond to the operation that the customer requested was desired. .

  The present invention has been made in view of the above background, and its purpose is to change a computer program and control parameters for driving a motor from an external device and to prevent an adverse effect due to a surge voltage or the like. To provide a tool.

  Another object of the present invention is to reduce the size of a power tool provided with a communication connector so that the external connection device and the power tool can be easily connected.

  Still another object of the present invention is to arrange the communication connector and the electrostatic protection means on one board and divert them to the connector part of various electric tools, thereby reducing the manufacturing cost by sharing parts. It is providing the electric tool which can implement | achieve.

  The characteristics of representative ones of the inventions disclosed in the present application will be described as follows.

  According to one aspect of the present invention, a motor for driving a tip tool, a control circuit board on which a control circuit for controlling rotation of the motor is mounted, and a communication line for connecting the control circuit and an external connection device are attached and detached. In the electric tool having the communication connector, the communication connector is arranged on a connector board provided separately from the control circuit board, and the connector board is provided with electrostatic protection means. The static electricity protection means can be constituted by a varistor that connects a communication line and a ground line. The varistor is formed in a chip shape, and may be arranged so as to connect a plurality of wirings constituting the communication line and the ground.

  According to another feature of the present invention, the housing of the electric tool includes a body portion extending in the front-rear direction, a handle portion extending downward from the body portion, and a battery holding portion provided at a lower portion of the handle portion, The communication connector is provided in a portion exposed when the battery of the battery holding unit is removed. The control circuit board is connected to a terminal base connected to the battery, and the connector board is fixed to the terminal base. The control circuit board is preferably arranged inside the battery holding unit. In this case, the control circuit board and the connector board are connected by a plurality of lead wires.

  According to still another feature of the present invention, only a socket type communication connector and an electrostatic protection component are mounted on the connector board. The communication connector includes a power supply line for supplying power from the outside. When a communication path is established, power is supplied from the outside to the control circuit.

  According to the first aspect of the present invention, the communication connector is disposed on the connector board provided separately from the control circuit board, and the connector board is provided with the electrostatic protection means, so that the static spark or the like is grounded to the communication connector. In addition, it is possible to effectively prevent a high voltage due to static electricity from being applied to the control circuit side, and it is possible to effectively protect electronic devices mounted on the control circuit board.

  According to the invention of claim 2, since the electrostatic protection means is a varistor for connecting the communication line and the ground line, it can be obtained at a low cost, and an increase in the manufacturing cost of the electric power tool can be minimized.

  According to the invention of claim 3, since the varistor is formed in a chip shape, and connects a plurality of wirings constituting the communication line and the ground, the apparatus is increased in size for mounting the electrostatic protection means. Thus, the electric tool can be reduced in size.

  According to the invention of claim 4, since the communication connector is provided in a portion exposed when the battery of the battery holding portion is removed, the tip tool of the electric tool is mistaken when the communication cable is connected to the communication connector. There is no fear of operating. Further, since the communication connector is covered by the battery during normal work, it is possible to effectively prevent water and dust from entering the communication connector.

  According to the invention of claim 5, since the connector board is fixed to the terminal base, it can be a connector board with an electrostatic protection means commonly used for a plurality of electric tools, and can be manufactured by sharing parts. Cost reduction can be realized.

  According to the sixth aspect of the present invention, the control circuit board is provided in the battery holding portion, and the control circuit board and the connector board are connected by the plurality of lead wires. , Increase in manufacturing cost and weight can be suppressed.

  According to the invention of claim 7, since only the socket type communication connector and the electrostatic protection component are mounted on the connector board, the connector board can be miniaturized.

  According to the invention of claim 8, the communication connector includes a power supply line for supplying power from outside, and when the communication path is established, power is supplied from the outside to the control circuit. Even when the battery is removed, the control circuit and the external connection device can communicate with each other.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

It is a longitudinal section showing the whole structure of electric tool 1 concerning the example of the present invention. 1 is a side view of a power tool 1 according to an embodiment of the present invention. It is a bottom view of electric tool 1 in the state where battery pack 2 was removed. FIG. 4 is a bottom view of the electric power tool 1 with the battery pack 2 removed, showing a state in which the socket cover 46 is opened and the communication connector 47b is opened. It is sectional drawing which shows the detailed shape of the control circuit board 9 and the base 41 part. It is a perspective view which shows the shape of the base 41, and is the figure seen from the upper side (control circuit board 9 side). It is a block diagram of a control circuit of electric tool 1 concerning the example of the present invention. It is a side view which shows the structure of the connector board | substrate 47a (surface). It is a side view which shows the structure of the connector board | substrate 47a (back surface).

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the upper and lower directions are described as the directions shown in the drawings.

  FIG. 1 is a longitudinal sectional view showing the entire structure of an electric power tool 1 according to the present invention, and shows a state in which a battery pack 2 can be attached and work can be performed as a tool. The electric power tool 1 uses a rechargeable battery pack 2 as a power source, drives a striking mechanism 30 using a motor 3 as a driving source, and applies a rotational force and / or striking force to an anvil 32 that is an output shaft, thereby providing a driver bit or the like A continuous rotational force or intermittent striking force is transmitted to a tip tool (not shown) to perform operations such as screw tightening and bolt tightening.

  In the brushless DC motor type motor 3, a rotor 3a having a permanent magnet is rotated inside a stator 3b. The motor 3 is accommodated in a substantially cylindrical body portion 6a of a housing 6 having a substantially T-shape when viewed from the side so that the axial direction of the rotary shaft 4 coincides with the front-rear direction. The housing 6 can be divided into two substantially right and left members having a substantially symmetrical shape, and these members are fixed by a plurality of screws (not shown). Therefore, a plurality of screw bosses 19b are formed in one of the divided housings 6 (left housing in this embodiment), and a plurality of screw holes are formed in the other housing (right housing) (not shown). The rotating shaft 4 of the motor 3 is rotatably held by a bearing 17b on the rear end side of the body portion 6a and a bearing 17a provided near the center portion.

  An inverter circuit board 10 on which a plurality of switching elements 11 are mounted is provided behind the motor 3. The inverter circuit board 10 is an annular multilayer board having substantially the same diameter as the outer shape of the motor 3, and six switching elements 11 such as FETs (Field Effect Transistors) are provided on the back surface (rear surface) of the inverter circuit board 10. Is installed. A rotational position detecting element (not shown) such as a Hall IC for detecting the position of the rotor 3a is provided on the surface (front surface) of the inverter circuit board 10 and facing the permanent magnet of the rotor. Is installed.

  A trigger operating portion 8a and a forward / reverse switching lever 14 are provided at an upper portion in the handle portion 6b integrally extending downward from the body portion 6a of the housing 6 in a substantially perpendicular direction, and the trigger switch 8 is biased by a spring (not shown). A trigger operation portion 8a protruding from the handle portion 6b is provided. A switch board 7 is provided below the trigger switch 8. Further, an LED light 12 is provided at a lower position of the hammer case 22 connected to the front end side of the body portion 6a. The LED light 12 irradiates the vicinity of the front end of the bit when a bit as a tip tool (not shown) is mounted in the mounting hole 32a.

  A control circuit board 9 having a function of controlling the speed of the motor 3 by the pulling operation of the trigger operation portion 8a is accommodated in the battery holding portion 6c below the handle portion 6b. On the control circuit board 9, a microcomputer (Micro Computer) 61 that controls driving of the motor 3 is mounted. A communication terminal 47 with an external connection device connected to the microcomputer 61 is provided in the lower part of the control circuit board 9. The communication terminal 47 is exposed to the outside by removing the battery pack 2, and a connection cable (not shown) can be attached.

  The control circuit board 9 is electrically connected to the battery pack 2 and the trigger switch 8. The control circuit board 9 is connected to the inverter circuit board 10 via the motor flat cable 80. The motor flat cable 80 can be composed of, for example, 20 flexible printed circuit boards (FPCs). The control circuit board 9 is connected to the switch board 7 via the switch flat cable 81. Similarly, the switch flat cable 81 can be configured by FPC. The control circuit board 9 is provided with terminals (terminals) that come into contact with the positive electrode and the negative electrode of the battery pack 2. One end of a power supply line 83 is connected to these terminals, and the other end of the power supply line 83 is connected to the switch board 7. As the power supply line 83, two wires for plus and minus are used.

  A battery pack 2 containing a plurality of battery cells such as nickel metal hydride and lithium ions is detachably attached to a battery holding portion 6c of the housing 6 formed below the handle portion 6b. The battery pack 2 has an extending portion 2a that extends to the inside of the handle portion 6b of the housing 6 and has a substantially L-shape when viewed from the side as shown in FIG. The battery pack 2 is provided with a release button 2b, and the battery pack 2 can be detached from the battery holding portion 6c by moving the battery pack 2 downward while pressing the release buttons 2b located on the left and right sides.

  A cooling fan 18 that is attached to the rotary shaft 4 and rotates in synchronization with the motor 3 is provided in front of the motor 3. The cooling fan 18 is a centrifugal fan that sucks air near the rotating shaft 4 and discharges it radially outward regardless of the rotation direction. The cooling fan 18 is provided on the side of the rear side of the body portion 6a. Air is sucked from the intake port 13a. The outside air sucked into the housing 6 reaches the cooling fan 18 after passing between the rotor and the stator of the motor 3 and between the magnetic poles of the stator, and near the outer peripheral side in the radial direction of the cooling fan 18. Are discharged to the outside of the housing 6 through a plurality of air outlets (see FIG. 2 described later).

  The striking mechanism 30 is mainly composed of two parts, an anvil 32 and a planetary carrier assembly 31, and the planetary carrier assembly 31 connects the rotating shaft of the planetary gear of the speed reduction mechanism 20 and strikes the anvil 32. It has a hammer which will be described later. The speed reduction mechanism 20 in this embodiment is a planetary type, has one speed reduction mechanism, and includes a sun gear, a plurality of planetary gears, and a ring gear. Unlike known hitting mechanisms that are widely used today, the hitting mechanism 30 does not have a cam mechanism having a spindle, a spring, a cam groove, a ball, and the like. And the anvil 32 and the planetary carrier assembly 31 are connected so that only relative rotation of less than half rotation is possible by a fitting shaft and a fitting hole formed near the rotation center. The anvil 32 is configured integrally with an output shaft portion on which a tip tool (not shown) is mounted, and a mounting hole 32a having a hexagonal cross section in the axial direction and the vertical plane is formed at the front end. The anvil 32 and the output shaft on which the tip tool is mounted may be configured as separate parts and connected.

  The rear side of the anvil 32 is connected to the fitting shaft of the planet carrier assembly 31, and is held rotatably with respect to the hammer case 22 by the metal 16a near the center in the axial direction. At the tip of the anvil 32, a sleeve 15 for attaching and detaching the tip tool with one touch is provided. The hammer case 22 is manufactured by metal integral molding to accommodate the striking mechanism 30 and the speed reduction mechanism 20, and holds the anvil 32 via the bearing mechanism. The hammer case 22 is fixed so as to be entirely covered by the left and right divided housing 6.

  When the trigger operation unit 8a is pulled and the motor 3 is started, the rotation of the motor 3 is decelerated by the speed reduction mechanism 20, and the planetary carrier assembly 31 rotates at a rotation rate of a predetermined ratio with respect to the rotation rate of the motor 3. To do. When the planet carrier assembly 31 rotates, the rotational force is transmitted to the anvil 32 via a hammer provided in the planet carrier assembly 31, and the anvil 32 starts to rotate at the same speed as the planet carrier assembly 31. When the force applied to the anvil 32 is increased by the reaction force received from the tip tool side, for example, the microcomputer mounted on the control circuit board 9 detects an increase in the tightening reaction force, and the rotation of the motor 3 stops and enters the locked state. Prior to this, the drive mode of the planetary carrier assembly 31 is changed to drive the hammer intermittently. The operation of the striking mechanism 30 is disclosed in, for example, Patent Document 1 and will not be described in detail here.

  An inner cover 21 is provided inside the body portion 6 a and on the front side of the cooling fan 18. The inner cover 21 is a member manufactured by integral molding of synthetic resin such as plastic, and is attached along the inner wall of the housing. A cylindrical portion is formed on the rear side of the inner cover 21, and a bearing 17 a and a bearing 16 b are provided for fixing the rotating shaft 4 of the motor 3 to be rotatable.

  FIG. 2 is a side view of the electric power tool 1 according to the embodiment of the present invention. The housing 6 includes three parts (a body part 6a, a handle part 6b, and a battery holding part 6c), and an air discharge port 13b for discharging cooling air is provided in the vicinity of the outer peripheral side of the cooling fan 18 in the radial direction of the body part 6a. It is formed. The housing 6 is formed in a left-right divided manner on a vertical plane passing through the rotation shaft 4 of the motor 3, and the housing 6 that can be divided into left and right by a plurality of screws 19 a is fixed. On the front side of the housing 6, a sleeve 15 constituting a tip tool holding portion projects. Although not visible in FIG. 2, a mode changeover switch and a mode display LED (both described later) for switching the drive mode (drill mode, impact mode) of the motor 3 are provided on the left side surface of the battery holding portion 6 c of the housing 6.

  FIG. 3 is a bottom view of the electric tool 1 with the battery pack 2 removed. The housing 6 is divided into a right housing 6-1 and a left housing 6-2. A battery housing chamber 45 for housing the extending portion 2a of the battery pack 2 is formed near the inside of the handle portion 6b of the housing 6. Near the front of the battery storage chamber 45, three terminals for contacting the contacts of the battery pack 2, that is, a plus terminal 42, an LD terminal 43, and a minus terminal 44 are provided. These three terminals are held by the flat plate-like portion of the base 41. The base 41 is configured to include two flat plate portions of a power terminal holding portion 41a for holding three terminals and a communication terminal holding portion 41b for fixing a communication terminal which is a feature of the present invention. Manufactured by integral molding of polymer resin such as plastic. The base 41 is fixed by sandwiching the left and right sides and the front side by the right housing 6-1 and the left housing 6-2. However, the fixing method is not limited to this, and the base 41 may be fixed by a known fixing method such as screwing. 41 may be fixed to the housing 6.

  The communication terminal holding portion 41b is provided with a communication terminal 47, and a socket cover 46 is attached to the opening 41c of the base 41 for exposing the communication terminal 47. The socket cover 46 is a cover that covers the opening 41c so that a communication connector 47b, which will be described later, is not exposed to the outside of the housing 6 when not in use, and covers the substantially rectangular flat plate portion 46a and the flat plate portion 46a as communication terminals. A support portion 46b for holding the holding portion 41b so as to be rotatable, and a handle portion 46c formed at a position in front of the flat plate portion 46a and away from the support portion 46b. . As the structure and attachment method of the socket cover 46, various known methods can be used. In this embodiment, the flat plate portion 46a is held so as not to be detached from the communication terminal holding portion 41b by elastic deformation of the rubber attachment portion. The flat plate portion 46a is held so as to be substantially rotatable. The material of the socket cover 46 can be arbitrarily selected as long as it is a member that can provide a dustproof and waterproof effect. For example, the socket cover 46 is preferably made of a resilient member such as rubber or plastic. The handle portion 46c serves as a lock mechanism for fixing the flat plate portion 46a fitted in the opening 41c so as not to be removed, and also serves as a knob when opening the flat plate portion 46a. In this embodiment, a groove is formed in the base 41 where the handle portion 46c of the communication terminal holding portion 41b is located, and a lock mechanism that stably holds the socket cover 46 by pushing the handle portion 46c into this groove. Acts as

  FIG. 4 is a bottom view of the electric tool 1 with the battery pack 2 removed, showing a state in which the socket cover 46 is opened and the communication connector 47b is opened. The socket cover 46 is opened about 90 degrees or more around the support portion 46b, and the flat plate portion 46a of the socket cover 46 is disposed so as to extend in the vertical direction. In this state, the female communication connector 47b is exposed. As the communication connector 47b, a general-purpose connector that can secure five communication circuits can be used. However, for example, a mini-B socket / female (receptacle) conforming to the USB (Universal Serial Bus) standard is used because of cost. good. Even when a mini-B socket conforming to the USB standard is used, the USB standard may be used for the communication procedure, or the communication may be performed using another communication standard while keeping the socket shape as it is. In this embodiment, communication is performed according to the RS-232C standard while using the USB standard communication connector 47b.

  FIG. 5 is a diagram showing the detailed shapes of the control circuit board 9 and the base 41, and shows a cross section taken along the line AA of FIG. The connector board 47a on which the communication connector 47b is mounted is composed of parts different from the control circuit board 9. A base 41 is attached to the lower side of the control circuit board 9 with screws 49. The base 41 is configured to include two parts, a power terminal holding part 41a and a communication terminal holding part 41b (see FIGS. 3 and 4) that are formed in steps so that the positions in the vertical direction are different. A communication connector 47b is provided inside the communication terminal holding portion 41b. The communication terminal 47 includes a connector board 47a and a communication connector 47b fixed thereto.

  The communication connector 47b is arranged so that the mini B male plug connector of the USB cable can be inserted from the bottom upward. The communication connector 47b is mounted on the connector board 47a and wired from the connector board 47a to the control circuit board 9 by a plurality of lead wires 48. The opening of the communication connector 47b is disposed so as to be positioned in the opening 41c of the base 41, and the opening 41c of the base 41 is closed by the socket cover 46 when not in use. At the end of the socket cover 46, a support portion 46b is formed as a cylindrical portion extending upward. The support portion 46b is inserted into the through hole 41d having a round cross section provided in front of the opening 41c of the communication terminal holding portion 41b, and is not separated from the through hole 41d near the center of the cylindrical portion. An umbrella-like portion 46e is provided.

  Thus, since the opening 41c is tightly sealed by the socket cover 46 when the connector is not connected, it can be electrically insulated and can prevent foreign matter from entering between the terminals of the communication connector 47b, and a short circuit between the terminals. Can be prevented. Further, by using the socket cover 46, a high waterproof effect can be obtained in addition to the dustproof effect.

  FIG. 6 is a perspective view showing the shape of the base 41, as viewed from the upper side (control circuit board 9 side). The base 41 is manufactured by integral molding of synthetic resin such as plastic, and is configured to cast three power terminals (plus terminal 42, LD terminal 43, minus terminal 44). A communication terminal 47 is fixed in front of the power supply terminal. The communication terminal 47 is mainly configured by a communication connector 47b and a connector board 47a that holds the connector 47b. The connector board 47a is guided by the groove and fixed to the communication terminal holding part 41b by two screws 50. A mode changeover switch 52 and four mode display LEDs 58 are provided in front of the left side of the base 41. By pressing the mode switch 52, the control mode of the motor 3, for example, a drill mode, a clutch mode, and an impact mode can be switched. By pressing the mode switch 52, the strength may be changed in each control mode.

  Next, a block diagram of a control circuit of the electric power tool 1 will be described with reference to FIG. When the battery pack 2 is attached to the electric power tool 1, a direct current of a predetermined voltage is supplied from the battery pack 2 to the power supply unit 66 and the motor supply power control unit 65. The motor supply power control unit 65 is configured by an inverter circuit including six switching elements 11 such as FETs connected in a three-phase bridge format, and is mounted on the inverter circuit board 10. The inverter circuit is controlled by the microcomputer 61, and the motor 3 is adjusted by adjusting the current supply to the predetermined phase of the star-connected stator windings U, V, W of the motor 3 by controlling the gate voltage of the switching element 11. Rotation control is performed.

  The motor 3 is composed of a three-phase brushless DC motor. This brushless DC motor is a so-called inner rotor type, and includes a rotor (rotor) including a plurality of sets of permanent magnets (magnets) including N poles and S poles, and a star-connected three-phase fixed. A stator including the sub windings U, V, and W is included. The motor 3 includes motor information for detecting three hall elements arranged at predetermined intervals in the circumferential direction, for example, at an angle of 60 °, and a current value flowing through the motor 3 in order to detect the rotational position of the rotor. A detection unit 64 is provided.

  The microcomputer 61 has a program storage unit 62 composed of a nonvolatile memory for storing a program, and a commercially available 16-bit or 32-bit microprocessor can be used. The microcomputer 61 drives the motor supply power control unit 65 based on the position detection signal from the motor information detection unit 64, so that the pulse width of the PWM signal (based on the detection signal of the operation amount (stroke) of the trigger switch 8 ( The amount of power supplied from the motor supply power control unit 65 to the motor 3 is adjusted by changing the duty ratio, and the start / stop and rotation speed of the motor 3 are controlled.

  For example, the microcomputer 61 operates with a direct current of 5 V, and the power source 66 steps down the direct current of the battery pack 2 for driving. A mode changeover switch 52 and a mode display LED 58 are connected to the microcomputer 61, and when the operator operates the mode changeover switch 52, the selected operation mode is displayed by the mode display LED 58. In this embodiment, the mode display LED 58 is composed of four LEDs, and the operation mode is displayed by the display pattern of each LED.

  Further, an ON / OFF control signal line for the LED light 12 and an output line from the trigger switch 8 are connected to the microcomputer 61. Further, an information storage unit 63 having a memory space used by a computer program executed in the microcomputer 61 is connected. The information storage unit 63 is preferably a known non-volatile memory such as a flash memory, but may be another known volatile or non-volatile memory.

  A plurality of computer programs are stored in advance in the program storage unit 62 of the microcomputer 61, and control parameters for specifying the computer program to be used are stored. The contents stored in the program storage unit 62 can be read and written from the external connection device 100 via the power supply connection cable 67. Therefore, the designation of the computer program to be executed by the microcomputer 61 can be changed by rewriting the control parameter from the external connection device 100. For this purpose, in this embodiment, the external connection device 100 and the power tool 1 are configured to be connectable using a communication cable.

  The communication cable is formed of two power supply connection cables 67 and a conversion cable set 110. The power supply type connection cable 67 is a cable in which a USB mini-A male connector 67a on the electric tool 1 side is formed and the other is a USB-A male connector 67b, which is widely distributed for personal computers. Cable. The conversion cable set 110 includes a conversion box 111, a communication cable 112 that is two connection cables extending from the conversion box 111, and a power cable 113. A connector 112 a is provided at the tip of the communication cable 112, and a connector 113 a is provided at the tip of the power cable 113. The connector 112a is a 9-pin serial port (female) connected to the RS-232C connector (serial port) of the external connection device. The power cable 113 is provided to supply + 5V power to the communication connector 47b, and is assumed to be a USB connector (A terminal) for connecting to the USB connector 102 of the external connection device as the connector 113a. In the present embodiment, in the connection from the conversion cable set 110 to the external connection device 100, exchange of signals is performed using the communication cable 112, and only power supply is performed using the power cable 113.

  The conversion box 111 has a role of relaying a signal sent from the external connection device 100 in accordance with the RS-232C standard on a predetermined signal line of a general-purpose power supply connection cable 67 (that is, a USB cable). Fulfill. As a result, the signal flowing through the power supply connection cable 67 does not match the USB cable standard. Therefore, even if the USB-A male connector 67b of the power supply connection cable 67 is directly connected to the USB connector 102 of the external connection device 100, a communication path is not established.

  This is because the circuit configuration provided on the electric power tool 1 side can be simplified by using RS-232C instead of USB as the communication standard. Further, because of the nature of the electric power tool 1, it is desirable to eliminate the possibility that the user will easily connect to the external connection device 100 and modify the program. In this embodiment, although the power supply type connection cable 67 (that is, the USB cable) is used, since the communication with the electric tool 1 cannot be performed unless the dedicated conversion cable set 110 is used, the program and the like can be easily modified. Therefore, a highly reliable electric tool can be realized.

  The external connection device 100 can be a commercially available personal computer, but is not limited thereto, and other dedicated connection devices may be prepared. The contents rewritten from the external connection device 100 are not limited to the parameters stored in the program storage unit 62, but the stored computer program itself may be rewritten. Furthermore, the external connection device 100 can realize the object of the present embodiment as long as it can access only the program storage unit 62, but the external connection device 100 may be configured to directly communicate with the microcomputer 61.

  FIG. 8 is a side view showing the front side (front side) shape of the connector board 47a. The connector board 47a is provided with a plurality (here, five) of connection terminals 201 to 205, and the ends of the five lead wires 48 (see FIG. 5) are soldered. The connector substrate 47a is formed by wiring with a conductive material such as copper foil on a base material such as phenol resin or glass epoxy, and can be easily and inexpensively configured by etching or the like. The lead wires 201a to 205a are wirings for connecting the connection terminals 201 to 205 and predetermined terminals of the communication connector 47b. A communication connector 47b is fixed below the connector board 47a. The communication connector 47b has, for example, five terminals. In this embodiment, a USB standard mini-B socket / female is used from the viewpoint of availability and cost.

  Of the five connection terminals 201 to 205, 205 is a ground (portion connected to a reference potential point). The power supply connection cable 67 connected to the communication connector 47b has a USB mini-A male connector 67a, and can be inserted into the communication connector 47b by inserting it in the direction of the arrow.

  FIG. 9 is a side view showing the back side (rear side) shape of the connector substrate 47a. The connector board 47a is a double-sided board, and on the back side, a bypass wiring 210 is provided so as to be connected from the four connection terminals 201 to 204 to the ground connection terminal 205 via the electrostatic protection components 211 to 214. . The terminals on both sides of the electrostatic protection components 211 to 214 are fixed to the connection terminals 201 to 204 and the bypass wiring 210 by soldering. The electrostatic protection components 211 to 214 are also called surge protection devices (SPDs) and are, for example, chip-type varistors, and have a high resistance value between electrodes during normal use, and maintain an almost insulated state. When a surge voltage is generated for some reason and a high potential difference occurs between the terminals of the electrostatic protection components 211 to 214, the resistance value of the electrostatic protection components 211 to 214 decreases as it approaches zero, and the surge current is connected to the ground. By bypassing the terminal 205, the surge voltage can be suppressed, and important circuit parts such as the microcomputer 61 mounted on the control circuit board 9 can be protected.

  In this way, when an electrostatic spark or the like is grounded to the communication connector 47b exposed to the outside by removing the battery pack 2, a high voltage due to static electricity is not applied to the control circuit board 9 side. It is possible to protect the provided microcomputer 61. Further, by providing the electrostatic protection components 211 to 214 on the connector board 47a of the communication connector 47b exposed to the outside where the electrostatic spark is highly likely to be applied, it is protected from a high voltage at a position far from the microcomputer 61 to be protected. Things will be possible. As a result, even the small electrostatic protection components 211 to 214 can be protected from a high electrostatic voltage. The electrostatic protection components 211 to 214 are not limited to varistors, and may be other elements or devices as long as they perform the same function, for example, Zener diodes may be used.

  As described above, since the connector board 47a is protected from static electricity as in the present embodiment, the base 41 part or the connector board 47a part can be freely connected to various types of power tools. The connector substrate 47a can be shared by a plurality of types of tools, and the cost can be reduced by mass production. Therefore, the unit price of the connector board 47a can be reduced, and the cost of the electric tool can be reduced. Further, only the communication connector 47b and the small electrostatic protection components 211 to 214 are arranged on the connector board 47a. As a result, when the above-described connector board 47a is shared, the connector board 47a can be sufficiently reduced in size and can be easily installed in other various electric tools.

  As described above, according to the present invention, a power tool having a power tool control program rewriting system can be effectively protected from a surge voltage such as static electricity, and a highly reliable power tool can be realized. Further, it is possible to reduce the size of the electric tool having the electrostatic protection means and reduce the manufacturing cost due to the sharing of parts.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the above-mentioned Example, A various change is possible within the range which does not deviate from the meaning. For example, in the above-described example, the power tool is described as an impact driver, but the present invention can be similarly applied to other power tools and power tools having a communication terminal.

DESCRIPTION OF SYMBOLS 1 Electric tool 2 Battery pack 2a Extension part 2b Release button 3 Motor 3a Rotor 3b Stator 4 Rotating shaft 6 Housing 6a Body part 6b Handle part 6c Battery holding part 7 Switch board 8 Trigger switch 8a Trigger operation part 9 Control circuit board DESCRIPTION OF SYMBOLS 10 Inverter circuit board 11 Switching element 12 Light 13a Air inlet 13b Air outlet 14 Forward / reverse switching lever 15 Sleeve 16a Metal 16b, 17a, 17b Bearing 18 Cooling fan 19a Screw 19b Screw boss 20 Deceleration mechanism 21 Inner cover 22 Hammer case 30 Stroke Mechanism 31 Planetary carrier assembly 32 Anvil 32a Mounting hole 41 Base 1a Power supply terminal holding part 41b Communication terminal holding part 41c Opening part 41d Through hole 42 Positive terminal 43 LD terminal 44 Negative terminal 45 Battery housing chamber 46 Socket cover 46a Flat plate portion 46b Support portion 46c Handle portion 46d Rib 46e Umbrella portion 47 Communication terminal 47a Connector board 47b Communication connector 48 Lead wire 49 Screw 50 Screw 52 Mode changeover switch 58 Mode display LED 61 Microcomputer 62 Program Storage unit 63 Information storage unit 64 Motor information detection unit 65 Motor supply power control unit 66 Power supply unit 67 Power supply connection cable 67a USB mini-A male connector 67b USB-A male connector 80 Motor flat cable 81 Switch flat cable 83 Power supply Line 100 External connection device 101 RS232C connector 102 USB connector 110 Conversion cable set 111 Conversion box 112 Communication cable 112a Connector 113 Power supply cable 11 a connector 201 to 205 connecting terminal 210 bypass wires 211 to 214 ESD protection component

Claims (8)

A motor that drives the tip tool;
A control circuit board on which a control circuit for controlling rotation of the motor is mounted;
An electric tool having a communication connector for attaching and detaching a communication line connecting the control circuit and an external connection device,
The communication connector is disposed on a connector board provided separately from the control circuit board,
An electric power tool characterized in that an electrostatic protection means is provided on the connector board.   The electric tool according to claim 1, wherein the electrostatic protection means is a varistor that connects a communication line and a ground line.   3. The electric tool according to claim 1, wherein the varistor is formed in a chip shape, and is arranged so as to connect a plurality of wires constituting the communication line and a ground. The housing of the electric tool includes a body part extending in the front-rear direction, a handle part extending downward from the body part, and a battery holding part provided at a lower part of the handle part,
The power tool according to any one of claims 1 to 3, wherein the communication connector is provided in a portion exposed when the battery of the battery holding unit is removed. The control circuit board is connected to a terminal base connected to the battery,
The power tool according to claim 4, wherein the connector board is fixed to the terminal base. The control circuit board is provided in the battery holding unit,
The power tool according to claim 5, wherein the control circuit board and the connector board are connected by a plurality of lead wires.   The power tool according to any one of claims 1 to 6, wherein only a socket-type communication connector and an electrostatic protection component are mounted on the connector board. The power supply line for supplying power from outside is included in the communication connector, and power is supplied from the outside to the control circuit when a communication path is established. The power tool according to claim 7.

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