JP6044811B2 - Portable electric planer - Google Patents

Description

The present invention relates to a portable electric planer suitable for cutting the surface of a work material such as wood.

A basic configuration of a portable electric plane is disclosed in, for example, Patent Document 1 below. The structure and use method of the portable electric plane will be described with reference to FIG. In FIG. 9, a cutter block 10 driven by an electric motor is rotatably disposed at the center of the main body, and a cutter 11 is attached to the outer peripheral portion of the cutter block 10. Further, a front base 8 and a rear base 9 that are in contact with the work material 70 are attached to the lower part of the main body, and a rotatable stand 6 that protrudes from the bottom surface of the base is provided at the rear part of the rear base 9. At the time of non-cutting, the tip of the front base 8 and the stand 6 serve as a fulcrum, and a portable electric plane can be placed without damaging the work material 70. When using the portable electric planer, the front base 8 is advanced forward along the work material 70, and the work material 70 is cut by the rotation of the cutter accompanying the rotation of the cutter block 10. When the cutting starts, the rear base 9 is moved along the cutting surface and the main body is moved forward. Since the stand 6 is rotatable, it is lifted up to the cutting surface by the work material 70 as the main body advances.

JP 2009-113393 A (proposed by the present applicant)

The conventional portable electric planer uses a commutator motor (for example, a universal motor) using an electromagnet for both the rotor and the stator as the motor. For this reason, the commutator must be replaced after long-term use. In addition, a general commutator motor cannot control the stop position of the motor. In this case, there is room for improvement in terms of control, such as the rotational position of the cutter block being stopped cannot be made constant.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a portable electric planer that does not require replacement of a commutator and is easy to maintain.

One embodiment of the present invention is a portable electric plane . This portable electric plane is
A housing, a cutter block rotatably provided in the housing , a blade provided in the cutter block, a base portion attached to the lower side of the housing, and a rotationally driven drive of the cutter block incorporated in the housing. An electric motor, a control unit that controls the electric motor, and a sensor that detects a rotational position of the cutter block ,
The electric motor is Ri Oh brushless motor,
The control unit controls the brushless motor to stop the cutter block at a rotational position where the blade does not contact the plane when the portable electric plane is placed on a plane with the base portion down. It is characterized by that.

  The electric motor is provided with a magnet,
  A position detection board for detecting the rotational position of the electric motor by detecting the position of the magnet may be provided in the housing.

  The sensor may be arranged to face the end face of the cutter block.

The base portion may include a front base and a rear base, and a control circuit board on which the control portion is mounted may be provided between the rear base and the inner surface of the housing.

The control circuit board on which the control unit is mounted and the power supply board on which a switching element that supplies power to the brushless motor may be separate boards.

The base part may include a front base and a rear base, the control circuit board may be provided inside the handle part of the housing, and the power supply board may be provided between the rear base and the inner surface of the housing. .

A belt transmission mechanism that transmits the rotation of the brushless motor to the cutter block may be provided.

The control unit may notify the outside when the rotation speed of the brushless motor and the rotation speed of the cutter block are out of a predetermined rotation speed ratio range or stop the brushless motor.

Electric power may be supplied to the brushless motor from a secondary battery.

Electric power may be supplied to the brushless motor from an external AC power source.

It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

According to the present invention, it is possible to provide a portable electric planer that does not require commutator replacement and is easy to maintain.

The right view which made the cross section a part of portable electric plane 1 concerning an embodiment of the invention. FIG. 2 is a plan sectional view of the portable electric planer 1 shown in FIG. 1. FIG. 2 is a layout explanatory view of a power circuit board 40 and a control circuit board 50 in the housing 2 shown in FIG. The left view of the portable electric plane 1 shown in FIG. The enlarged left view of the cutter block 10 shown in FIG. The enlarged view which looked at the brushless motor 20 shown in FIG. 2 from the axial direction. The simple functional block diagram of the portable electric plane 1 shown in FIG. The flowchart of the stop operation | movement of the portable electric plane 1 shown in FIG. The right view which made the cross section a part of the basic composition of a portable electric plane.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

FIG. 1 is a right side view, partly in section, of a portable electric planer 1 according to an embodiment of the present invention. FIG. 2 is a plan sectional view of the portable electric planer 1. FIG. 3 is an explanatory view of the arrangement of the power circuit board 40 and the control circuit board 50 in the housing 2 of the portable electric planer 1. FIG. 4 is a left side view of the portable electric plane 1. FIG. 5 is an enlarged left side view of the cutter block 10 of the portable electric planer 1. FIG. 6 is an enlarged view of the brushless motor 20 of the portable electric plane 1 as seen from the axial direction. In FIG. 6, the winding (stator coil) is not shown. In FIG. 6, the flow of magnetic flux when the brushless motor 20 is not energized is indicated by arrows.

The portable electric plane 1 operates by receiving power supply from an AC power source such as a commercial power source via a power cord 5. In the portable electric planer 1, the cutter block 10 is rotatably supported by bearings 18 and 19 at the central portion in the housing 2. The cutter 11 is attached and fixed to the outer periphery of the cutter block 10 by a fastening member 35 such as a bolt. As shown in FIGS. 2 and 5, a sensor magnet 30 is provided (fixed) on the end surface of the cutter block 10. The blade position detection board 31 is provided in the housing 2 so as to face the sensor magnet 30 and detects the magnetic field of the sensor magnet 30. The electric motor that rotationally drives the cutter block 10 is a brushless motor 20.

The brushless motor 20 is provided behind the cutter block 10 in the housing 2. The output shaft 21 of the brushless motor 20 is rotatably supported by bearings 16 and 17. The stator core 24 is fixedly supported in the housing 2. A rotor core 22 is integrally provided on the output shaft 21, and a predetermined number (here, four poles) of plate-like magnets 23 are inserted and fixed to the rotor core 22 (FIG. 6). A sensor magnet 32 is provided (fixed) on the end surface of the rotor core 22. The motor position detection board 25 is provided in the housing 2 so as to face the sensor magnet 32 and detects the magnetic field of the sensor magnet 32. The cooling fan 26 is attached to the output shaft 21 and rotates integrally with the output shaft 21. The rotation of the output shaft 21 is transmitted to the cutter block 10 by a belt transmission mechanism (winding transmission mechanism) including pulleys 27 and 28 and a belt 29.

A front base 8 and a rear base 9 that are in contact with the work material 70 are attached to the lower portion of the housing 2. The front base 8 and the rear base 9 are examples of base portions. A stand 6 is rotatably provided at the rear portion of the rear base 9. The stand 6 is urged to stand up by a spring (not shown) (torsion coil spring) and protrudes from the lower surface of the rear base 9. The cut depth adjusting mechanism 7 is provided to adjust the cut depth of the work material by the blade 2 by moving the front base 8 up and down.

As shown in FIGS. 2 and 3, the power circuit board 40 is provided in the housing 2 so as to be positioned above the rear base 9. The power supply circuit board 40 includes a diode bridge 43 that rectifies a supply voltage from an AC power supply, a smoothing capacitor 41, and a switching element 42 (IGBT, FET, etc.) that is bridge-connected to form an inverter circuit. The As shown in FIG. 3, the control circuit board 50 is provided inside the handle portion 3. A microcomputer 51 is mounted on the control circuit board 50 as a control unit that controls the operation of the brushless motor 20. The power circuit board 40 and the control circuit board 50 are electrically connected to each other by a cable or the like.

Since each element mounted on the power circuit board 40 generates a large amount of heat, the housing 2 is provided with wind windows 12 and 13 (FIGS. 1, 2 and 4) on both sides of the power circuit board 40. The cooling air is taken in from the wind windows 12 and 13 by the rotation of the fan 26. The cooling air passes through the vent hole 15 provided in the partition wall 14 inside the housing 2 to the fan 26 side. Further, the housing 2 is provided with an air window 33 (FIG. 3) for cooling the brushless motor 20, and the cooling air is taken in from the air window 33 by the rotation of the fan 26. The cooling air passing through the fan 26 changes direction and passes through the space above the cutter block 10 and is discharged from the exhaust hole 34 shown in FIGS. 3 and 4. At this time, shavings splashed upward by the blade 11 enter the cooling air passage from the through-hole 36 shown in FIG. 3, ride on the cooling air and are discharged from the exhaust hole 34.

FIG. 7 is a simple functional block diagram of the portable electric plane 1. The power supply 45 outputs a DC voltage (for example, 5 V) necessary for the operation of the microcomputer 51. The microcomputer 51 controls the inverter circuit 44 (a bridge circuit of the switching element 42 shown in FIG. 2) and applies an AC voltage to the brushless motor 20. The rotation of the brushless motor 20 is transmitted to the cutter block 10 by the belt transmission mechanism, and the cutter block 10 is rotationally driven. The motor position detection board 25 is equipped with a magnetic sensor such as a Hall IC, and detects the rotational position of the brushless motor 20 by detecting the magnetic field generated by the sensor magnet 32 shown in FIG. The blade position detection board 31 is equipped with a magnetic sensor such as a Hall IC, and the rotational position of the cutter block 10 (that is, the rotational position of the blade 11) is detected by detecting the magnetic field generated by the sensor magnet 30 shown in FIG. To detect. The blade position detection substrate 31 and the magnetic sensor correspond to position detection means for detecting the rotational position of the cutter block 10. Further, the microcomputer 51 monitors the rotation speed of the brushless motor 20 and the rotation speed of the cutter block 10, and the rotation speed ratio is within a predetermined rotation speed ratio range (for example, a range of ± 10% from the original rotation speed ratio). If it is out of the range, it is determined that the belt 29 is abnormal, such as deterioration of the belt 29, and is notified to the outside by the lighting of a lamp, the sound of a buzzer, or the like, or the rotation of the brushless motor 20 is stopped. If the belt 29 is not worn, the rotation speed of the brushless motor 20 and the rotation speed of the cutter block 10 are always the same, but if the belt 29 deteriorates due to wear or the like, it slips between the pulleys 28 and 29. Occurs, and the rotation speed ratio changes.

FIG. 8 is a flowchart of the stop operation of the portable electric plane 1. This flowchart starts from a state in which the user turns on the trigger switch 4 and the brushless motor 20 is rotating. If the user disconnects the trigger switch 4 in this state (Yes in S1), the microcomputer 51 reduces the rotational speed of the brushless motor 20 by reducing the duty ratio of the drive signal of the inverter circuit 44 (S2). When the microcomputer 51 confirms that the rotational speed N [rpm] of the brushless motor 20 is less than the predetermined N1 [rpm] (Yes in S3), the microcomputer 51 rotates the cutter block 10 based on the detection signal from the blade position detection board 31. The position is detected (S4), and the brushless motor 20 is completely stopped when the cutter block 10 reaches a predetermined rotational position (S6). At this time, the brushless motor 20 is completely stopped by the cogging torque unique to the permanent magnet motor. The predetermined rotation position is a position where the blade 11 does not protrude from the lower surface of the base portion, that is, a position where the blade 11 does not contact the plane when the portable electric plane 1 is placed on the plane. More specifically, this is a rotational position where the cutting edge of the blade 11 is disposed at a position deviated from the opening between the front base 8 and the rear base 9. At this time, of the two blades 11, the blade edge of which the blade edge is on the front side (front base 8 side) is at a position higher than the lower surface of the front base 8. Preferably, the predetermined rotation position is a position where the fastening member 35 that fixes the blade 11 faces downward as shown in FIG. In this case, the exchange work of the blade 11 becomes easy. Of the two blades 11, the blade edge of the blade edge on the rear side (rear base 9 side) is the cutter block at a rotational position 30 ° or more, preferably 45 ° or more before the position closest to the front end of the rear base 9. 10 stops. By stopping at this position, when the work is started with the portable electric planer 1 pressed against the wood in the next work, the cutter block 10 comes into contact with the wood with a certain degree of acceleration. The start will be smooth.

According to the present embodiment, the following effects can be achieved.

(1) By using the brushless motor 20 for the electric motor that rotationally drives the cutter block 10, unlike the conventional case where a commutator motor in which both the rotor and the stator are electromagnets is used, the cogging torque unique to the permanent magnet motor Can be used to control the rotation stop position of the brushless motor 20. For this reason, it becomes possible to stop the brushless motor 20 at a position where the cutter 11 does not protrude from the lower surface of the base portion, and even if the stand 6 is not raised, the workpiece 70 is not damaged and the cutter 11 is deteriorated. Without a portable electric plane 1 can be placed. Moreover, even if the main body is accidentally pushed or an impact is applied and the stand 6 is inadvertently detached, it is possible to prevent the work material 70 from being damaged or the blade 11 from being deteriorated.

(2) By monitoring the number of rotations of the brushless motor 20 and the number of rotations of the cutter block 10, it is possible to quickly detect an abnormality such as deterioration of the belt 29.

(3) Since the power supply circuit board 40 on which the element that generates a large amount of heat is mounted and the control circuit board 50 on which the microcomputer 51, which is vulnerable to heat, are arranged as separate boards, the heat generation of the power supply circuit board 40 is caused by the microcomputer. It is possible to prevent the operation of 51 from being adversely affected.

The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

The stand 6 shown in the embodiment may be omitted. Depending on the amount of heat generated by the power circuit board 40, the power circuit board 40 and the control circuit board 50 may be a single board. The brushless motor 20 is not limited to being driven by an AC power source such as a commercial power source, and may be driven by a secondary battery.

DESCRIPTION OF SYMBOLS 1 Portable electric plane, 2 Housing, 3 Handle part, 4 Trigger switch, 5 Power cord, 6 Stand, 7 Cutting depth adjustment mechanism, 8 Front base, 9 Rear base, 10 Cutter block, 11 Cutlery, 12, 13 Wind window, 14 Partition, 15 Ventilation hole, 16-19 Bearing, 20 Brushless motor, 21 Output shaft, 22 Rotor core, 23 Magnet, 24 Stator core, 25 Motor position detection board, 26 Fan, 27, 28 Pulley, 29 Belt, 30 Sensor magnet, 31 Blade position detection board, 32 Sensor magnet, 33 Air window, 34 Exhaust hole, 35 Fastening member, 36 Through hole, 40 Power supply circuit board, 41 Capacitor, 42 Switching element, 43 Diode bridge, 44 Inverter circuit, 45 Power supply, 50 control Circuit board, 51 microcomputer, 70 Workpiece

Claims (10)

A housing, a cutter block rotatably provided in the housing , a blade provided in the cutter block, a base portion attached to the lower side of the housing, and a rotationally driven drive of the cutter block incorporated in the housing. An electric motor, a control unit that controls the electric motor, and a sensor that detects a rotational position of the cutter block ,
The electric motor is Ri Oh brushless motor,
The control unit controls the brushless motor to stop the cutter block at a rotational position where the blade does not contact the plane when the portable electric plane is placed on a plane with the base portion down. A portable electric planer characterized by that.   The electric motor is provided with a magnet,
  The portable electric planer according to claim 1, wherein a position detection board for detecting a rotation position of the electric motor by detecting a position of the magnet is provided in the housing.   The portable electric plane according to claim 1 or 2, wherein the sensor is arranged to face an end face of the cutter block.   The said base part contains a front base and a rear base, The control circuit board carrying the said control part is provided between the said rear base and the inner surface of the said housing, The description in any one of Claim 1 to 3 Portable electric planer.   4. The portable electric device according to claim 1, wherein the control circuit board on which the control unit is mounted and the power supply board on which a switching element for supplying power to the brushless motor is provided are separate boards. 5. Kanna.   The base part includes a front base and a rear base, the control circuit board is provided inside a handle part of the housing, and the power supply board is provided between the rear base and the inner surface of the housing. Item 6. A portable electric planer according to Item 5.   The portable electric planner according to any one of claims 1 to 6, further comprising a belt transmission mechanism that transmits rotation of the brushless motor to the cutter block.   The portable unit according to claim 7, wherein the control unit notifies the outside or stops the brushless motor when the rotational speed of the brushless motor and the rotational speed of the cutter block are out of a predetermined rotational speed ratio range. Electric planer.   The portable electric plane according to any one of claims 1 to 8, wherein electric power is supplied to the brushless motor from a secondary battery.   The portable electric plane according to any one of claims 1 to 8, wherein electric power is supplied to the brushless motor from an external AC power source.

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