JP5407669B2 - Work machine - Google Patents

Description

  The present invention relates to a work machine using an electric motor as a drive source.

  An example of a work machine that uses an electric motor as a drive source is an electric brush cutter that cuts grass or the like with a blade. The number of electric brush cutters is increasing due to lower running costs and improved motor performance compared to engine brush cutters that use gasoline.

  Many of the electric brush cutters are provided with a pipe-shaped operating rod extending from an operating handle, and a motor is held at the tip thereof. Electric power for driving the electric motor is supplied to the electric motor from a power supply unit provided on the handle via a wiring inserted into the operation rod.

  In addition, an electric brush cutter in which the above-described operation rod can be extended and contracted is known. For example, Patent Literature 1 discloses an electric brush cutter that includes a plurality of pipes that can be divided and connected to an operation rod. Since this electric brush cutter can change the length of the operating rod in accordance with the work environment, it has good operability.

Japanese Utility Model Publication No. 7-36612

  According to the electric brush cutter described in Patent Document 1, the length of the wiring connecting the power supply unit and the electric motor, that is, the resistance changes according to the number of pipes constituting the operation rod. Voltage and output change. Therefore, there is a case where the output of the electric motor cannot be sufficiently obtained depending on the work environment.

  In a work machine using an electric motor as a drive source, the motor load may fluctuate greatly depending on the work environment, and stable output may not be obtained.

  In view of the above problems, an object of the present invention is to provide a work machine capable of obtaining a stable output according to a work environment.

In order to achieve the above object, a work machine according to a first aspect of the present invention includes:
A power supply unit arranged on the operation pole;
A voltage converting means disposed on the operation pole and converting and outputting a voltage input from the power supply unit;
An electric motor disposed on the operating rod away from the power supply unit;
A power line that is inserted into the operation rod and applies the output voltage of the voltage conversion means to the electric motor;
A tool part that operates by receiving the power of the electric motor,
The operation rod and the power line are configured by an operation rod unit configured to be separable and connectable in the longitudinal direction between the voltage conversion means and the electric motor.
The voltage conversion means and the electric motor are configured to be connectable to each other by removing at least one operation rod unit,
A connection state detecting means for detecting a connection state of the power line;
The voltage conversion means controls the output voltage based on the connection state of the power line detected by the connection state detection means.
It is characterized by that.

The voltage conversion means controls the output voltage so that the applied voltage of the electric motor matches a predetermined reference value.
It is desirable.

The connection state detection means detects an applied voltage of the electric motor,
The voltage conversion means controls the output voltage based on the applied voltage detected by the connection state detection means.
It is desirable.

The connection state detection means detects a resistance value of the power line connected between the voltage conversion means and the electric motor,
The voltage conversion means controls the output voltage based on the resistance value detected by the connection state detection means.
It is desirable.

The connection state detection means further detects a load fluctuation of the electric motor,
The voltage conversion means further controls the output voltage based on the load fluctuation detected by the connection state detection means.
It is desirable.

A work machine according to a second aspect of the present invention is:
A power supply unit arranged on the operation pole;
A voltage converting means disposed on the operation pole and converting and outputting a voltage input from the power supply unit;
An electric motor disposed on the operating rod away from the power supply unit;
A power line that is inserted into the operation rod and applies the output voltage of the voltage conversion means to the electric motor;
A tool part that operates by receiving the power of the electric motor;
Voltage detecting means for detecting an applied voltage of the electric motor;
With
The voltage conversion means controls an output voltage based on an applied voltage of the electric motor detected by the voltage detection means.
It is characterized by that.

The voltage conversion means obtains a deviation between the applied voltage of the electric motor detected by the voltage detection means and a predetermined reference value, and controls the output voltage so that the deviation becomes zero.
It is desirable.

The voltage detection means further detects a load fluctuation of the electric motor,
The voltage converting means further controls the output voltage based on the load fluctuation detected by the voltage detecting means.
It is desirable.

The tool portion is configured to be detachable from the electric motor,
A plurality of the tool parts having different forms depending on work contents can be mounted on the electric motor and operated.
It is desirable.

The electric motor is configured to be detachable from the operation rod.
A plurality of the electric motors having different forms depending on work contents can be mounted on the operation rod and operated.
It is desirable.

The power supply unit is configured to be detachable from the operation rod.
A plurality of the power supply units having different power supply voltages can be attached to the operation rod,
The voltage conversion means converts the output voltage of the power supply unit so as to match the target value in response to the power supply voltage of the power supply unit, and outputs it.
It is desirable.

The power supply unit and the electric motor are arranged at one end and the other end of the operation rod, respectively.
The operating rod is provided with a work handle between the power supply unit and the electric motor.
It is desirable.

The voltage conversion means is provided in the vicinity of the power supply unit.
It is desirable.

  ADVANTAGE OF THE INVENTION According to this invention, the working machine which can obtain the stable output according to a working environment can be provided.

The side view which shows the electric brush cutter which concerns on embodiment of this invention. The side view which divides and shows the electric brush cutter shown by FIG. The side view which shows the electric brush cutter shown by FIG. 1 by connecting a handle | steering-wheel part and a motor part. Sectional drawing which shows the handle | steering-wheel part of the electric brush cutter shown by FIG. Sectional drawing which shows the operating rod unit of the electric brush cutter shown by FIG. Sectional drawing which shows the motor part of the electric brush cutter shown by FIG. Sectional drawing which shows the joint part of the electric brush cutter shown by FIG. 1 in the (a) divided state, (b) the connected state, (c) the state which can be divided | segmented. The right view which shows the convex joint part shown by FIG. The left view which shows the concave joint part shown by FIG. The functional block diagram which shows the drive control circuit of the electric brush cutter shown by FIG. The operation | movement flowchart which shows the output voltage control process of the voltage converter circuit shown by FIG. The functional block diagram which shows the drive control circuit of the electric brush cutter shown by FIG. The operation | movement flowchart which shows the output voltage control process of the voltage converter circuit shown by FIG. The side view which shows the cultivator which concerns on embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(Embodiment 1)
The working machine according to the first embodiment is an electric brush cutter 1 shown in FIGS. 1 and 2. The electric brush cutter 1 includes a handle portion 10, an operating rod unit 20, and a motor portion 30. As shown in FIG. 2, the handle portion 10, the operating rod unit 20, and the motor portion 30 can be connected to and divided from each other via a joint portion 3 including a convex joint portion 40 and a concave joint portion 50. It is configured. And as shown in FIG. 3, it is possible to connect the handle | steering-wheel part 10 and the motor part 30 directly.

  As shown in FIG. 4, the handle portion 10 includes a gripping portion 13, a pipe 11 provided at the front end portion of the gripping portion 13, a convex joint portion 40 provided at the front end portion of the pipe 11, and a gripping portion 13. The power source unit 15 provided at the rear end portion, the voltage control board 100 accommodated at the rear end portion of the gripping portion 13, and the wiring 12 inserted through the pipe 1 are configured.

  The grip portion 13 is formed in a handle shape so that the user holds the electric brush cutter 1. In addition, the grip 13 is provided with a trigger switch 14 for driving and stopping the electric brush cutter 1.

  The pipe 11 is a hollow tube formed from steel or an aluminum alloy.

  The convex joint part 40 can connect the operating joint unit 20 or the concave joint part 50 of the motor part 30 so that attachment or detachment is possible.

  The power supply unit 15 is a supply source of electric power consumed by the electric brush cutter 1 and includes a secondary battery that can be attached to and detached from the grip unit 13.

  The voltage control board 100 includes a voltage conversion circuit 101 that constitutes a drive control circuit 500 (FIG. 10), which will be described later, and mainly serves to convert and output the output voltage of the power supply unit 15.

  The wiring 12 includes two power supply lines 12a and 12b and one signal line 12c. The wiring 12 is inserted into the pipe 11 from the voltage control board 100 and extends to the convex joint section 40.

  As shown in FIG. 5, the operating rod unit 20 includes a pipe 21, a concave joint 50 and a convex joint 40 provided at one end and the other end of the pipe 21, and a wiring 22 inserted through the pipe 21. , Is composed of.

  The pipe 21 is a hollow tube formed of steel, an aluminum alloy, or the like, and has an outer diameter and an inner diameter that are substantially equal to the pipe 11 of the handle portion 10.

  The concave joint part 50 can detachably connect the convex joint part 40 of the handle part 10 or other operating rod unit 20. Moreover, the convex joint part 40 can connect the concave joint part 50 of the motor part 30 or the other operating rod unit 20 so that attachment or detachment is possible.

  The wiring 22 is composed of two power supply lines 22a and 22b and one signal line 22c corresponding to the wiring 12 (power supply lines 12a and 12b and signal line 12c) of the handle portion 10, and has a concave joint. It extends from the portion 50 to the convex joint portion 40.

  As shown in FIG. 1, an auxiliary handle 29 is provided in one of the operation rod units 20. The auxiliary handle 29 is configured to be detachable at a desired position of the operating rod unit 20. Therefore, the operator can work by holding the handle portion 10 and the auxiliary handle 29.

  As shown in FIG. 6, the motor unit 30 includes a pipe 31, a concave joint unit 50 provided at one end of the pipe 31, a motor housing 33 provided at the other end of the pipe 31, and a motor housing 33. The motor 34 and the motor control board 300 accommodated therein, and the wiring 32 inserted from the motor control board 300 into the pipe 31 are configured.

  The pipe 31 is a hollow tube formed of steel, aluminum alloy, or the like, and has an outer diameter and an inner diameter that are substantially equal to the pipe 11 of the handle portion 10 and the pipe 21 of the operating rod unit 20.

  The concave joint portion 50 can be detachably connected to the handle portion 10 or the convex joint portion 40 of the operating rod unit 20.

  The motor housing 33 accommodates the motor 34 and the motor control board 300.

  The motor 34 is a three-phase brushless DC motor. The motor control board 300 includes an inverter 301, a control signal output circuit 302, an arithmetic unit 303, and the like that constitute a drive control circuit 500 (FIG. 10) to be described later, and mainly plays a role of driving and controlling the motor 34.

  The wiring 32 corresponds to the wiring 12 (power supply lines 12a and 12b and the signal line 12c) of the handle portion 10 and the wiring 22 (power supply lines 22a and 22b and the signal line 22c) of the operation rod unit 20 and corresponds to two power supply lines. 32 a and 32 b and one signal line 32 c, and is inserted into the pipe 31 from the concave joint portion 50 and extends to the motor control board 300.

  A disc-shaped blade 38 for cutting grass or the like is detachably fixed to the rotating shaft of the motor 34. The pipe 31 is provided with a protective cover 39 that covers a part of the blade 38.

  Next, the joint part 3 which connects the handle | steering-wheel part 10, the operating rod unit 20, and the motor part 30 to each other is demonstrated in detail. As described above, the joint portion 3 includes the convex joint portion 40 and the concave joint portion 50.

  The convex joint part 40 is provided in the handle part 10 and the operating rod unit 20. As shown in FIG. 7A, the convex joint portion 40 includes a pipe 41 and a substantially cylindrical plug 43 that protrudes from the end of the pipe 41. A wiring 42 composed of two power supply lines 42a and 42b and one signal line 42c is inserted into the pipe 41. The plug 43 includes three pins 44a to 44c projecting from the end face corresponding to the wiring 42 (power supply lines 42a and 42b and signal line 42c). The three pins 44a to 44c are electrically connected to two power supply lines 42a and 42b and one signal line 42c, respectively.

  The pipe 41 corresponds to the pipe 11 of the handle portion 10 and the pipe 21 of the operating rod unit 20. Further, the wiring 42 (power supply lines 42a, 42b and signal line 42c) is composed of the wiring 12 (power supply lines 12a, 12b and signal line 12c) of the handle portion 10 and the wiring 22 (power supply lines 22a, 22b and signal of the operation rod unit 20). This corresponds to the line 22c).

  The concave joint part 50 is provided in the operating rod unit 20 and the motor part 30. The concave joint portion 50 is composed of a pipe 51 and a substantially cylindrical socket 53 that is submerged at the end of the pipe 51. The pipe 51 is inserted with a wiring 52 composed of two power supply lines 52a and 52b and one signal line 52c. The socket 53 includes three pins 54a to 54c embedded in the end surface corresponding to the wiring 52 (power supply lines 52a and 52b and signal line 52c). The three pins 54a to 54c are electrically connected to the two power supply lines 52a and 52b and the one signal line 42c, respectively.

  The pipe 51 corresponds to the pipe 21 of the operating rod unit 20 and the pipe 31 of the motor unit 30. Further, the wiring 52 (power supply lines 52a, 52b and signal line 52c) is composed of the wiring 22 (power supply lines 22a, 22b and signal line 22c) of the operating rod unit 20 and the wiring 32 (power supply lines 32a, 32b and signal of the motor unit 30). This corresponds to the line 32c).

  The plug 43 of the convex joint part 40 is formed so as to be able to fit with the pipe 51 of the concave joint part 50. As shown in FIGS. 7A and 8, a pair of concave guides 46 are formed on the outer peripheral surface of the plug 43. As shown in FIGS. 7A and 9, a pair of convex guides 56 are formed on the inner peripheral surface of the pipe 51 corresponding to the concave guide 46 of the plug 43. The concave guide 46 and the convex guide 56 are positioned so that when the plug 43 and the pipe 51 are fitted, the pins 44a to 44c of the plug 43 and the grooves 55a to 55c of the socket 53 are aligned. And when the plug 43 of the convex joint part 40 is inserted in the pipe 51 of the concave joint part 50, as shown in FIG.7 (b), the pins 44a-44c and the pins 54a-54c are each electrically connected. The

  Furthermore, as shown to Fig.7 (a)-(c), the joint part 3 is provided with the locking mechanism 60 which fixes the convex joint part 40 and the concave joint part 50 in the connected state. The locking mechanism 60 includes a locking groove 61 formed in the plug 43 of the convex joint portion 40 and an arm 62 provided in the pipe 51 of the concave joint portion 50.

  The locking groove 61 of the convex joint portion 40 is formed on the outer peripheral surface of the plug 43 and has a surface substantially perpendicular to the axis of the pipe 41. The arm 62 of the concave joint portion 50 is provided on the outer peripheral portion of the pipe 51 and is pivotally supported around a pin 63 provided substantially perpendicular to the axis of the pipe 51. The pin 63 is supported by an arm cover 64 provided on the outer peripheral portion of the pipe 51. At one end and the other end of the arm 62, a claw portion 62a and a separation button 62b are formed with a pin 63 interposed therebetween. The claw 62 a is formed in a claw shape, and can protrude into the pipe 51 from the hole 65 formed in the pipe 51 as the arm 62 rotates. A compression spring 66 is provided between the separation button 62b and the pipe 51, and the separation button 62b is urged so as to be separated from the pipe 51 and the claw portion 62a to protrude into the pipe 51. .

  As shown in FIG. 7B, when the convex joint portion 40 and the concave joint portion 50 are connected, the locking groove 61 of the plug 41 and the claw portion 62a of the arm 62 are engaged, and the convex joint portion 40 is engaged. And the concave joint portion 50 are prevented from coming off. Further, as shown in FIG. 7C, when the separation button 62b of the arm 62 is pressed as indicated by an arrow 67, the engagement between the locking groove 61 of the plug 41 and the claw portion 62a of the arm 62 is released, The convex joint part 40 and the concave joint part 50 can be separated.

  As can be understood from the above description, the joint unit 3 mechanically connects the handle unit 10, the operating rod unit 20, and the motor unit 30, and at the same time electrically connects the wiring 12, the wiring 22, and the wiring 32. The voltage control board 100 of the handle part 10 and the motor control board 300 of the motor part 30 are electrically connected.

  The wiring 12/22/32 connecting the voltage control board 100 and the motor control board 300 has two power supply lines 12a, 12b / 22a, 22b / 32a, 32b and one signal line 12c / 22c. It is not limited to / 32c, and can be appropriately changed according to the configuration of the drive control circuit 500 described later. Similarly, the pin arrangement of the convex joint portion 40 and the concave joint portion 50 can be changed as appropriate corresponding to the wiring 12, the wiring 22, and the wiring 32.

  Next, the drive control circuit 500 that drives the electric brush cutter 1 having the above-described configuration will be described.

  As illustrated in FIG. 10, the drive control circuit 500 includes a power supply unit 15, a voltage conversion circuit 101, a connection state detection circuit 102, a motor 34, an inverter 301, a control signal output circuit 302, a calculation unit 303, The rotation position detection element 304, the rotation position detection circuit 305, and the rotation number detection circuit 306 are configured.

  The voltage conversion circuit 101 is disposed on the voltage control board 100 of the handle unit 10. Further, the connection state detection circuit 102, the inverter 301, the control signal output circuit 302, the calculation unit 303, the rotation position detection circuit 305, and the rotation number detection circuit 306 are arranged on the motor control board 300 of the motor unit 30.

  The power supply unit 15 is a direct current power source composed of a secondary battery, and is connected to the voltage conversion circuit 101.

  The voltage conversion circuit 101 includes a regulator or the like, converts a voltage input from the power supply unit 15 into a predetermined voltage, and outputs the voltage to the inverter 301. The voltage conversion circuit 101 and the inverter 301 are connected by power supply lines 5 a and 5 b constituting the wiring 5. In addition, the voltage conversion circuit 101 and the calculation unit 303 are connected by a signal line 5 c constituting the wiring 5.

  The motor 34 is composed of a three-phase brushless DC motor composed of a rotor 35 and a stator winding 36. The rotor 35 is composed of a two-pole magnet, and the stator winding 36 is composed of a star-connected three-phase (U, V, W phase) winding.

  The inverter 301 includes six insulated gate bipolar transistors (IGBT, hereinafter referred to as transistors) Q1 to Q6 connected in a three-phase bridge form, and six fly (not shown) connected between the collectors and emitters of the transistors Q1 to Q6. And a wheel diode. The collectors of the three transistors Q1 to Q3 are connected to the positive power supply line 5a extending from the voltage conversion circuit 101, and the emitters are connected to the U, V, and W phases of the stator winding 36 of the motor 34, respectively. The collectors of the three transistors Q4 to Q6 are connected to the U, V, and W phases of the stator winding 36 of the motor 34, respectively, and the emitters are connected to the negative power supply line 5b extending from the voltage conversion circuit 101. . The gates of the six transistors Q1 to Q6 are connected to the control signal output circuit 302.

  The control signal output circuit 302 outputs a control signal to the gates of the transistors Q1 to Q6 of the inverter 301 in accordance with the switching element drive signal input from the arithmetic unit 303, and causes the transistors Q1 to Q6 to perform a switching operation. As a result, the DC voltage applied from the voltage conversion circuit 101 to the inverter 301 is converted into a three-phase (U, V, W phase) driving voltage for driving the motor 34.

  The three rotational position detection elements 304 are arranged close to the rotor 35 of the motor 34 and have a phase difference of 120 ° (electrical angle) from each other. The rotational position detection element 304 is constituted by a so-called Hall IC, detects the magnetic pole of the rotor 35, and outputs a detection signal to the rotational position detection circuit 305.

  The rotational position detection circuit 305 detects the rotational position of the rotor 35 based on the detection signals input from the three rotational position detection elements 304, and outputs the rotational position detection signal indicating the detected rotational position to the arithmetic unit 303 and the rotational speed. Output to the detection circuit 306.

  The rotation speed detection circuit 306 detects the rotation speed of the rotor 35 based on the rotation position detection signal input from the rotation position detection circuit 305, and outputs a rotation speed detection signal indicating the detected rotation speed to the calculation unit 303. .

  Based on the rotational position detection signal input from the rotational position detection circuit 305 and the rotational speed detection signal input from the rotational speed detection circuit 306, the calculation unit 303 is configured so that the motor 34 rotates at a predetermined rotational speed. The switching element drive signal for controlling the transistors Q1 to Q6 of the 301 is output to the control signal output circuit 302.

  The wiring 5 (power supply lines 5a, 5b, signal line 5c) includes the wiring 12 (power supply lines 12a, 12b, signal line 12c) of the handle portion 10 and the wiring 22 (power supply lines 22a, 22c) of the operating rod unit 20. 22b, signal line 22c) and wiring 32 (power supply lines 32a, 32b, signal line 32c) of the motor unit 30. Therefore, the connection state (length; resistance) of the power supply lines 5a and 5b constituting the wiring 5 changes according to the number of operating rod units 20 connected between the handle part 10 and the motor part 30. At this time, assuming that the output voltage of the voltage conversion circuit 101 is constant, the voltage drop amount of the power supply lines 5a and 5b changes, so the applied voltage and output of the motor 34 change. Specifically, as the power supply lines 5a and 5b become longer, the voltage drop amount of the power supply lines 5a and 5b becomes larger, so the applied voltage and output of the motor 34 become smaller. Further, as the power supply lines 5a and 5b become shorter, the voltage drop amount of the power supply lines 5a and 5b increases, so that the applied voltage and output of the motor 34 increase.

  Further, the applied voltage and output of the motor 34 vary according to the load of the motor 34. Specifically, as the load on the motor 34 increases, the current flowing through the power supply lines 5a and 5b increases and the amount of voltage drop across the power supply lines 5a and 5b increases. Therefore, the applied voltage and output of the motor 34 are small. Become. Further, as the load on the motor 34 becomes smaller, the current flowing through the power supply lines 5a and 5b becomes smaller and the amount of voltage drop in the power supply line becomes smaller, so the applied voltage and output of the motor 34 become larger.

  Therefore, the drive control circuit 500 of the present embodiment controls the output voltage of the voltage conversion circuit 101 in accordance with the connection state of the power supply lines 5a and 5b and the load fluctuation of the motor 34, as will be described below. It has a function to stabilize voltage and output. Since the motor 34 is composed of a brushless DC motor, the applied voltage of the motor 34 means the input voltage of the inverter 301.

  The connection state detection circuit 102 detects the connection state of the power supply lines 5a and 5b and the load fluctuation of the motor 34 by detecting the voltage applied to the motor 34, and outputs a voltage detection signal indicating the detected voltage to the arithmetic unit 303. .

  The calculation unit 303 obtains a deviation between the voltage applied to the motor 34 and a predetermined reference value based on the voltage detection signal input from the connection state detection circuit 102, and the voltage conversion circuit 101 so that this deviation becomes zero. Output a step-up / step-down signal.

  The voltage conversion circuit 101 steps up / steps down the output voltage based on the step-up / step-down signal input from the calculation unit 303. Therefore, the applied voltage of the motor 34 is controlled to match the predetermined reference value according to the connection state of the power supply lines 5a and 5b and the load fluctuation of the motor 34, and the output of the motor 34 is stabilized.

  Next, the output voltage control process of the voltage conversion circuit 101 in the drive control circuit 500 will be described in detail with reference to the operation flow chart shown in FIG. For ease of understanding, it is assumed that the drive control circuit 500 starts the output voltage control process when a main power (not shown) is turned on, and ends the output voltage control process when the main power is turned off.

When the main power supply (not shown) is turned on, the voltage conversion circuit 101 outputs a predetermined voltage V ₁ (step S1). In this state, the drive control circuit 500 waits until the trigger switch 14 is turned ON (step S2, NO).

  When the trigger switch 14A is switched to ON (step S2, YES), the output voltage of the voltage conversion circuit 101 is applied to the inverter 301. Then, the motor 34 is driven by the calculation unit 303 (step S3).

Subsequently, the connection state detection circuit 102 outputs detects the applied voltage _{V M} of the motor 34 (step S4), and a voltage detection signal indicative of the voltage _{V M} detected to the operation unit 303. Then, the arithmetic unit 303, based on the voltage detection signal input from the connected state detecting circuit 102, a deviation between the applied voltage V _M and a predetermined reference value of the motor 34, so that the deviation becomes 0, The step-up / step-down signal is output to the voltage conversion circuit 101.

Next, the voltage conversion circuit 101 steps up / steps down the output voltage V ₁ based on the step-up / step-down signal input from the calculation unit 303. (Step S5).

  The drive control circuit 500 repeats the processes in steps S4 to S5 until the trigger switch 14 is switched off (step S6, NO).

  When the trigger switch 14 is switched to OFF (step S6, YES), the output voltage of the voltage conversion circuit 101 is cut off and the motor 34 is stopped (step S7).

  The drive control circuit 500 repeats the processes in steps S2 to S7 described above, and ends the output voltage control process when the main power supply (not shown) is disconnected.

  Note that the step-up / step-down signal output from the calculation unit 303 is not limited to the one that instructs the voltage conversion circuit 101 to step up / step down the output voltage. For example, the step-up / step-down amount is instructed to the voltage conversion circuit 101 or output. It may indicate a voltage target value.

  The voltage conversion circuit 101 and the calculation unit 303 of this embodiment constitute voltage conversion means according to claims 1 and 6. Further, the connection state detection circuit 102 of the present embodiment constitutes a connection state detection means according to claim 1 and a voltage detection means according to claim 6.

(Embodiment 2)
A drive control circuit 500A according to the second embodiment is a circuit that drives the above-described electric brush cutter 1 in place of the drive control circuit 500 of the first embodiment.

  As shown in FIG. 12, the drive control circuit 500A includes a power supply unit 15A, a voltage conversion circuit 101A, a connection state detection circuit 102A, a motor 34A, an inverter 301A, a control signal output circuit 302A, and a calculation unit 303A. , A rotational position detecting element 304A, a rotational position detecting circuit 305A, and a rotational speed detecting circuit 306A.

  The voltage conversion circuit 101A and the connection state detection circuit 102A are provided on the voltage control board 100A of the handle portion 10. The inverter 301 </ b> A, the control signal output circuit 302 </ b> A, the calculation unit 303 </ b> A, the rotation position detection circuit 305 </ b> A, and the rotation number detection circuit 306 </ b> A are provided on the motor control board 300 </ b> A of the motor unit 30.

  The power supply unit 15A is connected to the voltage conversion circuit 101A.

  The voltage conversion circuit 101A converts the voltage input from the power supply unit 15A into a predetermined voltage and outputs the voltage to the inverter 301A. The voltage conversion circuit 101A and the inverter 301A are connected by two power supply lines 5a and 5b constituting the wiring 5A.

  Similarly to the motor 34 of the first embodiment, the motor 34A is rotated at a predetermined speed by an inverter 301A, a control signal output circuit 302A, a calculation unit 303A, a rotational position detection element 304A, a rotational position detection circuit 305A, and a rotational speed detection circuit 306A. Controlled to drive by number.

  The wiring 5A (power supply lines 5a and 5b) includes the wiring 12 (power supply lines 12a and 12b) of the handle unit 10 described above, the wiring 22 (power supply lines 22a and 22b) of the operating rod unit 20, and the wiring 32 ( It consists of power lines 32a and 32b). Therefore, the connection state (length; resistance) of the power supply lines 5a and 5b constituting the wiring 5A changes according to the number of operating rod units 20 connected between the handle portion 10 and the motor 30. At this time, assuming that the output voltage of the voltage conversion circuit 101A is constant, the connection state of the power supply lines 5a and 5b changes, so the applied voltage and output of the motor 34A change.

  Assuming that the output voltage of the voltage conversion circuit 101A is constant, the current flowing through the power supply lines 5a and 5b and the motor 34A changes according to the connection state of the power supply lines 5a and 5b. Specifically, as the power supply lines 5a and 5b become longer, the current flowing through the power supply lines 5a and 5b and the motor 34A becomes smaller. Further, the shorter the power lines 5a and 5b, the larger the current flowing through the power lines 5a and 5b and the motor 34A.

  Therefore, the connection state detection circuit 102A detects the connection state of the power supply lines 5a and 5b by detecting the current flowing through the power supply lines 5a and 5b and the motor 34A. Then, the connection state detection circuit 102A, based on the connection state of the power supply lines 5a and 5b detected by the connection state detection circuit 102A, sets the target value of the output voltage so that the applied voltage of the motor 34A matches a predetermined reference value. Set. Thereby, the drive control circuit 500A has a function of stabilizing the output of the motor 34A. Since the motor 34A is composed of a brushless DC motor, the applied voltage of the motor 34A means the input voltage of the inverter 301A.

  The connection state detection circuit 102A is connected in parallel to the current detection resistor 103A connected in series to the power supply line 5b, detects the current flowing through the current detection resistor 103A (current flowing through the power supply lines 5a and 5b and the motor 34A), and A current detection signal indicating the detected current is output to the connection state detection circuit 101A.

  In the state where the motor 34A is rotating, the current flowing through the power supply lines 5a and 5b, the motor 34A, and the voltage detection resistor 103A varies according to the load of the motor 34A, and therefore the connection state detection circuit 102A is connected to the power supply line 5a. , 5b cannot be accurately detected. Therefore, as described below, the connection state detection circuit 102A detects the connection state of the power supply lines 5a and 5b while the motor 34A is stopped.

  The voltage conversion circuit 101A outputs a predetermined voltage sufficiently smaller than the rated voltage so that the motor 34A does not rotate. At this time, since the motor 34A does not rotate, any one of the transistors Q1 to Q3 and any one of the transistors Q4 to Q6 of the inverter 301A are maintained in the ON state. As a result, a steady current flows through the power supply line 5a, the inverter 301A, any two of the U, V, and W phases of the motor 34A, the power supply line 5b, and the current detection resistor 103A. The connection state detection circuit 102A monitors the current flowing through the current detection resistor 103A, and detects a steady current after a predetermined time has elapsed from the rise of the current. Here, since the output voltage of the voltage conversion circuit 101A, the ON resistance of the inverter 301A, the coil resistance of the motor 34A, and the resistance of the current detection resistor 103A are predetermined values, the current detected by the connection state detection circuit 102A is the power line It has a value corresponding to the connection state of 5a and 5b.

  Based on the current detection signal input from the connection state detection circuit 102A, the voltage conversion circuit 101A sets a target value for the output voltage with reference to a previously stored table. This table is set so that the voltage applied to the motor 34A matches a predetermined reference value according to the connection state of the power supply lines 5a and 5b. Specifically, as the power supply lines 5a and 5b are longer (shorter), the target value of the output voltage is set higher (lower). Then, the voltage conversion circuit 101A controls the output voltage so as to match the set target value. Therefore, the applied voltage of the motor 34A is controlled to match the predetermined reference value according to the connection state of the power supply lines 5a and 5b, and the output of the motor 34A is stabilized.

  Next, the output voltage control process A of the voltage conversion circuit 101A in the drive control circuit 500A described above will be described in detail with reference to the operation flowchart shown in FIG. For ease of understanding, it is assumed that the drive control circuit 500A starts the output voltage control process A when a main power (not shown) is turned on, and ends the output voltage control process A when the main power is turned off.

When the main power supply (not shown) is turned on, the voltage converting circuit 101A outputs a predetermined voltage _{V 0} (step S1). In this state, the drive control circuit 500A waits until the trigger switch 14A is turned ON (step S2, NO).

When the trigger switch 14A is switched to ON (step S2, YES), the output voltage of the voltage conversion circuit 101A is applied to the inverter 301A. Since voltage V ₀ is set sufficiently lower than the rated voltage of motor 34A, motor 34A does not rotate. Then, the current detection circuit 102A detects the steady current I ₀ flowing through the current detection resistor 103A (step S3), and outputs a current detection signal indicating the detected current I ₀ to the voltage conversion circuit 101A.

Next, the voltage conversion circuit 101A, based on the current detection signal input from the connection state detection circuit 102A, sets the target value (V ₁ ) of the output voltage so that the applied voltage of the motor 34A matches a predetermined reference value. Is set (step S4). Subsequently, the voltage conversion circuit 101A outputs a voltage V ₁ that matches the set target value (V ₁ ) (step S5). Then, the motor 34A is driven by the calculation unit 303A (step S6).

  The drive control circuit 500A continues to drive the motor 34A until the trigger switch 14A is switched off (step S7, NO). When the trigger switch 14A is switched off (step S7, YES), the output voltage of the voltage conversion circuit 101A is cut off and the motor 34A is stopped (step 8).

  Subsequently, the drive control circuit 500A waits until the trigger switch 14A is turned on (step S8, NO). When the trigger switch 14A is switched ON (step S8, YES), the output voltage of the voltage conversion circuit 101A is applied to the inverter 301A, and the motor 34A is driven again (step 6).

  The drive control circuit 500A repeats the processes in steps S6 to S9 described above, and ends the output voltage control process A when the main power supply (not shown) is disconnected.

  As described above, the electric brush cutter 1 having the above-described configuration can change the distance between the handle unit 10 and the motor unit 30 by dividing or connecting the operation rod unit 20. Therefore, work can be performed efficiently according to the work environment. Further, by dividing the handle portion 10, the operating rod unit 20, and the motor portion 30, storage and transportation are facilitated.

  In addition, since the power supply unit 15 and the motor 34 are disposed at one end and the other end of the operating rod unit 20 and the auxiliary handle 29 is provided in the operating rod unit 20, the weight balance is good and the operability is good.

  Then, by providing the voltage conversion circuit 101 (101A) close to the power supply unit 15 (15A), it is possible to effectively use the surplus space of the handle unit 10 and to reduce the size of the electric brush cutter 1.

  Moreover, since the drive control circuit 500 (500A) for driving the electric brush cutter 1 includes the voltage conversion circuit 101 (101A) for converting the output voltage of the power supply unit 15 (15A), for example, discharging of the secondary battery Thus, the applied voltage and output of the motor 34 (34A) can be stabilized in accordance with the voltage fluctuation of the power supply unit 15 (15A). Furthermore, not only a dedicated secondary battery having a predetermined battery voltage, but also several secondary batteries having different battery voltages can be used.

  Further, the connection state detection circuit 102 (102A) detects the connection state of the power supply lines 5a and 5b inserted through the operation rod unit 20, and the voltage conversion circuit 101 (101A) is based on the connection state of the power supply lines 5a and 5b. Since the output voltage is controlled, a stable output can be obtained according to the number of operating rod units 20 to be mounted.

  Furthermore, according to the drive control circuit 500 of the first embodiment, the connection state detection circuit 102 detects the load fluctuation of the motor 34, and the voltage conversion circuit 101 controls the output voltage based on the load fluctuation of the motor 34. Stable output can be obtained according to the environment.

  In addition, this invention is not limited to the above-mentioned embodiment, What changed variously in the range described in the claim is also contained in the technical scope of this invention.

  For example, the present invention is not limited to the electric brush cutter exemplified in the above-described embodiment, and may be a working machine such as a cultivator, a lawn mower, or a trimmer as long as it is a working machine using an electric motor as a power source. Can be widely applied. Furthermore, the present invention is not limited to a working machine that uses a secondary battery, and can also be applied to a working machine that uses an AC power source, for example.

  Further, for example, a plurality of electric motors having different forms may be mounted on the operating rod in correspondence with a cultivator, a lawn mower, a trimmer, or the like. For example, the cultivator 2 shown in FIG. 11 is a cultivator motor unit that replaces the handle unit 10 and the operating rod unit 20 of the electric brush cutter 1 and the motor unit 30 of the electric brush cutter 1 shown in the embodiment. 90. The illustrated cultivator is a working machine that digs up soil, and has a larger motor load than a working machine such as an electric brush cutter. A work machine that performs such a heavy load work has a large current consumption and a large voltage drop in the power supply line, so that the applied voltage and output of the electric motor become a problem. Since the voltage is controlled to match a predetermined reference value, a stable output can be obtained. In addition, a plurality of tool portions having different forms may be configured to be attachable to the electric motor.

  Further, for example, a plurality of power supply units having different forms such as a plurality of secondary batteries having different voltages and capacities and an adapter that converts and supplies the voltage of the AC power supply may be mounted on the operation rod. Good.

  Furthermore, the object of the present invention is to provide a work machine capable of obtaining a stable output against load fluctuations of the electric motor. The present invention is not limited to a working machine, and can be applied to working machines having various forms.

  In addition, the material, shape, quantity, arrangement, function, and the like of each component can be changed as appropriate within a range in which the object of the present invention can be achieved.

DESCRIPTION OF SYMBOLS 1 Electric brush cutter 2 Cultivator 3 Joint part 5 Wiring 5a, b Power supply line 5c Signal line 10 Handle part 11 Pipe 12 Wiring 12a, b Power supply line 12c Signal line 13 Grip part 14 Trigger switch 15 Power supply part 20 Control rod unit 21 Pipe 22 Wiring 22a, b Power line 22c Signal line 29 Auxiliary handle 30 Motor unit 31 Pipe 32 Wiring 32a, b Power line 32c Signal line 33 Motor housing 34, 34A Motor 35, 35A Rotor 36, 36A Stator winding 38 Blade 39 Protective cover 40 Convex joint part 41 Pipe 42 Wiring 42a, b Power supply line 42c Signal line 43 Plug 44a-44c Pin 46 Concave guide 50 Concave joint part 51 Pipe 52 Wiring 52a, b Power supply line 52c Signal line 53 Socket 54a-54c Pin 56 Convex guide 60 Locking machine 61 Locking groove 62 Arm 62a Claw part 62b Separation button 63 Pin 64 Arm cover 65 Hole part 66 Compression spring 90 Cultivator motor part 100, 100A Voltage control board 101, 101A Voltage conversion circuit 102, 102A Connection state detection circuit 103A Current Detection resistors 300, 300A Motor control boards 301, 301A Inverters 302, 302A Control signal output circuits 303, 303A Calculation units 304, 304A Rotation position detection elements 305, 305A Rotation position detection circuits 306, 306A Rotation number detection circuits 500, 500A Drive control circuit

Claims (10)

A power supply unit arranged on the operation pole;
A voltage converting means disposed on the operation pole and converting and outputting a voltage input from the power supply unit;
An electric motor disposed on the operating rod away from the power supply unit;
A power line that is inserted into the operation rod and applies the output voltage of the voltage conversion means to the electric motor;
A tool part that operates by receiving the power of the electric motor,
The operation rod and the power line are configured by an operation rod unit configured to be separable and connectable in the longitudinal direction between the voltage conversion means and the electric motor.
The voltage conversion means and the electric motor are configured to be connectable to each other by removing at least one operation rod unit,
A connection state detecting means for detecting a connection state of the power line;
The voltage conversion means controls the output voltage based on the connection state of the power line detected by the connection state detection means.
A working machine characterized by that. The voltage conversion means controls the output voltage so that the applied voltage of the electric motor matches a predetermined reference value.
The work machine according to claim 1, wherein: The connection state detection means detects an applied voltage of the electric motor,
The voltage conversion means controls the output voltage based on the applied voltage detected by the connection state detection means.
The work machine according to claim 1 or 2, wherein The connection state detection means detects a resistance value of the power line connected between the voltage conversion means and the electric motor,
The voltage conversion means controls the output voltage based on the resistance value detected by the connection state detection means.
The work machine according to claim 1 or 2, wherein The connection state detection means further detects a load fluctuation of the electric motor,
The voltage conversion means further controls the output voltage based on the load fluctuation detected by the connection state detection means.
The work machine according to any one of claims 1 to 4, characterized in that: The tool portion is configured to be detachable from the electric motor,
A plurality of the tool parts having different forms depending on work contents can be mounted on the electric motor and operated.
The work machine according to any one of claims 1 to 5 , wherein: The electric motor is configured to be detachable from the operation rod.
A plurality of the electric motors having different forms depending on work contents can be mounted on the operation rod and operated.
Working machine according to any one of claims 1 to 6, characterized in that. The power supply unit is configured to be detachable from the operation rod.
A plurality of the power supply units having different power supply voltages can be attached to the operation rod,
The voltage conversion means converts the output voltage of the power supply unit so as to match the target value in response to the power supply voltage of the power supply unit, and outputs it.
The work machine according to any one of claims 1 to 7 , characterized in that: The power supply unit and the electric motor are arranged at one end and the other end of the operation rod, respectively.
The operating rod is provided with a work handle between the power supply unit and the electric motor.
The work machine according to any one of claims 1 to 8 , characterized in that: The voltage conversion means is provided in the vicinity of the power supply unit.
The work machine according to any one of claims 1 to 9 , wherein

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