Electric working machine, and method of detecting overload operation thereof
First Claim
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1. An electric working machine comprising:
- a motor configured to generate a driving force for driving a tool portion attached to the electric working machine;
a drive circuit configured to drive the monitor;
a speed setting unit configured to set a rotation speed of the motor;
a load detection unit configured to detect a magnitude of a load on the motor;
a determination unit configured to calculate an estimated value of a heat generation amount of the motor from the magnitude of the load detected by the load detection unit when the motor rotates, and to determine that the motor is in an overload operation state when the estimated value reaches a predetermined threshold; and
a parameter setting unit configured to set a parameter used for calculating the estimated value in accordance with the rotation speed without being coupled to a detection circuit that detects a temperature of the motor and/or a temperature of the drive circuit, the parameter setting unit being further configured to set the parameter so that the estimated value quickly reaches the threshold as the rotation speed set by the speed setting unit decreases,wherein the load detection unit k configured to detect a current flowing through a conduction path provided between a power source and the motor,wherein the estimated value of the heat generation amount of the motor is based on the current detected by the load detection unit,wherein the determination unit includes a heating counter,wherein the parameter includes a count parameter for incrementing the heating counter,wherein the parameter setting unit is configured to set the count parameter to quickly increment the heating counter as the rotation speed set by the speed setting unit decreases,wherein the determination unit is configured to increment a count value of the heating counter based on the count parameter, andwherein the count value of the heating counter corresponds to the estimated value.
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Abstract
An electric working machine according to one aspect of the present disclosure comprises a motor, a speed setting unit, a load detection unit, a determination unit, and a parameter setting unit. The determination unit calculates an estimated value of a heat generation amount of the motor, and determines that the motor is in an overload operation state when the estimated value reaches a predetermined threshold. The parameter setting unit sets a parameter to be used for calculating the estimated value and/or the threshold in accordance with a rotation speed set by the speed setting unit.
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Citations
19 Claims
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1. An electric working machine comprising:
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a motor configured to generate a driving force for driving a tool portion attached to the electric working machine; a drive circuit configured to drive the monitor; a speed setting unit configured to set a rotation speed of the motor; a load detection unit configured to detect a magnitude of a load on the motor; a determination unit configured to calculate an estimated value of a heat generation amount of the motor from the magnitude of the load detected by the load detection unit when the motor rotates, and to determine that the motor is in an overload operation state when the estimated value reaches a predetermined threshold; and a parameter setting unit configured to set a parameter used for calculating the estimated value in accordance with the rotation speed without being coupled to a detection circuit that detects a temperature of the motor and/or a temperature of the drive circuit, the parameter setting unit being further configured to set the parameter so that the estimated value quickly reaches the threshold as the rotation speed set by the speed setting unit decreases, wherein the load detection unit k configured to detect a current flowing through a conduction path provided between a power source and the motor, wherein the estimated value of the heat generation amount of the motor is based on the current detected by the load detection unit, wherein the determination unit includes a heating counter, wherein the parameter includes a count parameter for incrementing the heating counter, wherein the parameter setting unit is configured to set the count parameter to quickly increment the heating counter as the rotation speed set by the speed setting unit decreases, wherein the determination unit is configured to increment a count value of the heating counter based on the count parameter, and wherein the count value of the heating counter corresponds to the estimated value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of detecting that a motor of an electric working machine is in an overload operating state, the method comprising:
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setting a rotation speed of the motor; detecting a magnitude of a load on the motor by detecting a current flowing through a conduction path provided between a power source and the motor; calculating, with a heating counter, an estimated value of a heat generation amount of the motor based on the magnitude of the load, wherein the estimated value of the heat generation amount of the motor is based on the current flowing through the conduction path; determining that the motor is in an overload operation state when the estimated value reaches a predetermined threshold; and setting a parameter used for calculating the estimated value based on the magnitude of the load in accordance with the rotation speed without being coupled to a detection circuit that detects a temperature of the motor and/or a temperature of the drive circuit, wherein the parameter is set so that the estimated value quickly reaches the threshold as the rotation speed decreases, wherein the parameter includes a count parameter for incrementing the heating counter, wherein setting a parameter used for calculating the estimated value based on the magnitude of the load in accordance with the rotation speed without being coupled to a detection circuit that detects a temperature of the motor and/or a temperature of the drive circuit includes setting the count parameter to quickly increment the heating counter as the set rotation speed decreases, wherein calculating, with a heating counter, an estimated value of a heat generation amount of the motor based on the magnitude of the load includes incrementing a count value of the heating counter based on the count parameter, and wherein the count value of the heating counter corresponds to the estimated value.
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15. An electric working machine comprising;
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a motor configured to generate a driving force for driving a tool portion attached to the electric working machine; a speed setting unit configured to set a rotation speed of the motor; a load detection unit configured to detect a magnitude of a load on the motor; a determination unit configured to calculate an estimated value of a heat generation amount of the motor from the magnitude of the load detected by the load detection unit when the motor rotates, and to determine that the motor is in an overload operation state when the estimated value reaches a predetermined threshold; and a parameter setting unit configured to set a parameter used for calculating the estimated value and/or the threshold in accordance with the rotation speed set by the speed setting unit, wherein the load detection unit is configured to detect a current flowing through a conduction path provided between a power source and the motor, wherein the estimated value of the heat generation amount of the motor is based on the current detected by the load detection unit, wherein the parameter includes a heating addition value, wherein the parameter setting unit is configured to set the heating addition value so that the heating addition value increases as the rotation speed decreases, wherein the determination unit includes a heating counter, the determination unit being configured to increment the heating counter using the heat addition value set by the parameter setting unit when the magnitude of the load on the motor is higher than a predetermined set value, and wherein a count value of the heating counter corresponds to the estimated value. - View Dependent Claims (16, 17, 18, 19)
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Specification