JP2007204924A - Device for stopping electric motor when failed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for stopping an electric motor when failed, capable of automatically stopping an electric motor in failure of the regenerative brake function of the electric motor. <P>SOLUTION: This electric motor failure time stopping device has the electric motor having a mechanical brake 23 and operating a moving body, a failure discriminator 20 for discriminating the failure of the regenerative brake function when using this electric motor as a generator, and a mechanical brake operation control apparatus 22 for operating the mechanical brake 23 by discriminating the failure by this failure discriminator 20. The failure discriminator 20 outputs an ON signal to the mechanical brake operation control apparatus 22, when the temperature of the electric motor or an inverter detected by a temperature sensor 24 deviates from a preset temperature upper limit, and when deceleration arithmetically operated from an operation speed detected by a speed detector 26 deviates from a deceleration lower limit set in response to operation output. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor failure stop device that operates due to a failure of a regenerative braking function of an electric motor.

There is a hybrid construction vehicle provided with a hybrid system in which stop assistance and energy recovery are achieved by a regenerative braking function when an electric motor is used as a generator (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2005-133319 (page 4-5, FIG. 1)

  In such a hybrid construction vehicle, the driver has stepped on the pedal to activate another brake mechanism to ensure the stop function, but the motor's regenerative brake function has reduced function, deviated from the use range, etc. When a failure occurs, the motor cannot be stopped in response to these problems.

  The present invention has been made in view of these points, and an object thereof is to provide a motor failure stop device that can stop an electric motor when a regenerative braking function of the electric motor fails.

  The invention described in claim 1 includes an electric motor that includes a mechanical brake and operates an operating body, a fault discriminator that discriminates and processes a fault that includes a deterioration in the function of the regenerative braking function when the motor is used as a generator, and the fault discriminator. And a mechanical brake operation control device that activates the mechanical brake according to failure determination by a motor.

  According to a second aspect of the present invention, the failure discriminator in the motor failure stop device according to the first aspect is detected by the temperature sensor that detects the temperature of at least one of the motor and the inverter that controls the motor, and the temperature sensor. And a temperature upper limit deviation discriminator for determining that the temperature has deviated from the set temperature upper limit and outputting an ON signal.

  According to a third aspect of the present invention, the failure discriminator in the motor failure stop device according to the second aspect includes a speed detector that detects the operating speed of either the electric motor or an operating body operated by the electric motor, The deceleration lower limit limit is set according to the operation output to operate the body, and when it is determined that the deceleration calculated from the operating speed has deviated from the deceleration lower limit limit, an ON signal is output. A classifier, a component failure detector that detects a failure of the device that constitutes the motor and the inverter and outputs an ON signal, a temperature upper limit deviation deviation detector, a deceleration lower limit deviation deviation detector, and a component failure detector. An OR circuit that outputs an ON signal to the mechanical brake operation control device in response to an ON signal from at least one.

  According to a fourth aspect of the present invention, the failure discriminator in the motor failure stop device according to the third aspect sets an acceleration upper limit according to the operation output for operating the operating body, and from the acceleration upper limit, based on the operating speed Acceleration upper limit deviation discriminator that outputs an ON signal when it is determined that the calculated acceleration has deviated, temperature upper limit deviation deviation discriminator, deceleration lower limit deviation deviation discriminator, acceleration upper limit deviation discriminator and component equipment failure An OR circuit that outputs an ON signal to the mechanical brake operation control device in response to an ON signal from at least one of the detectors.

  According to a fifth aspect of the invention, the motor failure stop device according to any one of the first to fourth aspects is applied to an electric motor of a hybrid work machine.

  According to the first aspect of the present invention, at the time of a failure including a reduction in the function of the regenerative brake function of the motor, the mechanical brake operation control device operates the mechanical brake of the motor by the failure determination of the regenerative brake function by the failure determiner. The electric motor can be stopped by a mechanical brake that operates in response to a failure including a reduction in the function of the regenerative brake function. By automating the safety stop function, it becomes possible to perform normal deceleration operation only with the regenerative brake function while ensuring safety, and it is possible to contribute to an increase in efficiency by collecting regenerative energy.

  According to the second aspect of the present invention, the temperature upper limit deviation discriminator for judging that the temperature of the electric motor and the inverter detected by the temperature sensor has deviated from the set temperature upper limit and outputting an ON signal is provided. This makes it possible to limit the device usage conditions to a certain range, and to ensure a stop function even during operation outside the usage conditions, eliminating the need to increase the device capacity by unnecessarily tightening the usage conditions and rationalizing the device capacity. Can be set within a wide range.

  According to the invention described in claim 3, the mechanical brake is operated from the OR circuit by an ON signal from at least one of the temperature upper limit deviation discriminator, the deceleration lower limit deviation discriminator and the component equipment fault detector of the fault discriminator. Since an ON signal is output to the control device, if the temperature of at least one of the motor and inverter rises above the set upper temperature limit, the deceleration of the operating body operated by the motor will be the set deceleration. When decelerated from the lower limit, the motor can be stopped by the mechanical brake in any case where a failure occurs in the equipment constituting the motor and the inverter.

  According to the fourth aspect of the invention, when the acceleration upper limit deviation discriminator discriminates the acceleration deviating from the acceleration upper limit set according to the operation output, an on signal is output from the acceleration upper limit deviation discriminator. Then, since the ON signal is output from the OR circuit to the mechanical brake operation control device, it is possible to determine the runaway failure of the operating body and stop the electric motor by the mechanical brake.

  According to the fifth aspect of the present invention, when the regenerative brake function of the electric motor of the hybrid work machine has a failure, the mechanical brake operation control device operates the mechanical brake of the electric motor by the failure determination of the regenerative brake function by the failure determiner. Therefore, the electric motor can be stopped by a mechanical brake that operates according to a failure of the regenerative brake function.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS.

  FIG. 2 shows a hybrid system mounted on a hybrid hydraulic excavator 1 as a hybrid work machine, in which an upper swing body 3 turns to a lower travel body 2 that drives left and right crawler tracks by left and right traveling motors 2m, respectively. The upper rotating body 3 is mounted with a power unit 4 and a work unit 5 so as to be able to turn by the motor 3m. The left and right traveling motors 2m and the turning motor 3m are provided with mechanical brakes such as electromagnetic brakes (not shown) that are generally used during emergency stops.

  In the working device 5, a boom 6 that is turned up and down by a boom cylinder 6c with respect to the upper swing body 3 is pivotally supported, and an arm 7 that is turned by an arm cylinder 7c is rotatable at the tip of the boom 6. A bucket 8 that is rotated by a bucket cylinder 8c is pivotally supported at the tip of the arm 7.

  In the power unit 4, an engine 11 and an electric motor 12 are connected to a main pump 14 via a power transmission device 13, and the left and right traveling motors 2 m, the turning motor 3 m and the motor 12 are connected via an inverter 15 and a converter 16. A power storage device 17 such as a battery is connected.

  The left and right traveling motors 2m, the turning motor 3m, and the motor 12 are supplied with electric power from the power storage device 17 to drive the respective operating bodies (the lower traveling body 2, the upper turning body 3, and the main pump 14). When driven by an external force (downhill self-traveling force, turning inertia force, engine output), it can be controlled as a generator, and regenerative energy can be collected in the power storage device 17. At that time, the running motor 2m and the turning motor 3m Since it has a regenerative brake function, the regenerative brake can be applied.

  FIG. 1 shows whether the regenerative braking function of a traveling motor 2 m or a turning motor 3 m (hereinafter simply referred to as “motors 2 m, 3 m”) is normal or malfunctioning (this “failure” includes “degraded function”) A fault discriminator 20 for discriminating and processing a malfunction of the regenerative braking function when the motors 2m and 3m are used as a generator is shown. And a processing circuit 21 that is operated in response to a failure determination signal from the failure determiner 20, and this processing circuit 21 controls the operation of a mechanical brake 23 such as an emergency electromagnetic brake for the motors 2m and 3m. A mechanical brake operation control device 22 is provided.

  The failure discriminator 20 includes a motor / inverter temperature sensor 24 as a temperature sensor that detects the temperature of the inverter 2 that controls the motor 2m, 3m or the motor 2m, 3m, and this motor / inverter temperature sensor 24 has a temperature upper limit limit. The deviation discriminator 25 is connected. This temperature upper limit deviation discriminator 25 determines whether the temperature detected by the motor / inverter temperature sensor 24 has deviated beyond the set temperature upper limit, and the detected temperature is set. When it is determined that the temperature has exceeded the upper temperature limit, an ON signal “1” is output.

  The failure discriminator 20 operates the operating speed of the motors 2m and 3m or the operating bodies (hereinafter referred to as operating bodies 2 and 3) such as the lower traveling body 2 and the upper swing body 3 that are operated by the motors 2m and 3m. A speed detector 26 for detecting one of the speeds, an acceleration / deceleration calculation device 27 for calculating acceleration and deceleration from the operating speed detected by the speed detector 26, and a deceleration lower limit limit deviation discriminator 28 I have.

  This deceleration lower limit deviation discriminator 28 sets the deceleration lower limit limit according to the operation output output from the operating device (operating lever, etc.) in the cab that operates the actuators 2 and 3, and calculates acceleration / deceleration. An ON signal “1” is output when it is determined that the deceleration calculated from the operating speed by the device 27 has deviated from the deceleration lower limit set in accordance with the operation output.

  The failure discriminator 20 further includes an acceleration upper limit deviation discriminator 31. The acceleration upper limit deviation discriminator 31 sets the acceleration upper limit according to the operation output for operating the actuators 2 and 3, and the actuators 2 and 3 or the motors 2m and 3m detected by the speed detector 26. An ON signal “1” is output when it is determined that the acceleration calculated by the acceleration / deceleration calculating device 27 from the operating speed deviates from the acceleration upper limit set in accordance with the operation output.

  The acceleration upper limit deviation discriminator 31 discriminates the acceleration deviating from the acceleration upper limit even when the operation output for operating the operating bodies 2 and 3 is smaller than the predetermined set value set by the setting device 32. In some cases, the limit value can be automatically set according to the operation output so that the ON signal “1” can be output.

  Further, the failure discriminator 20 is provided with a component device failure detector 34 that detects a failure of the devices constituting the motors 2m and 3m or the inverter 15 and outputs an on signal “1”. The component equipment failure detector 34 is a device that makes a failure determination based on, for example, deviations of voltages and currents to the motors 2m and 3m out of a predetermined range.

  Further, the failure discriminator 20 includes an ON signal “1” from at least one of the temperature upper limit deviation discriminator 25, the deceleration lower limit limit deviation discriminator 28, the acceleration upper limit deviation discriminator 31 and the component equipment fault detector 34. Accordingly, an OR circuit 35 for outputting an ON signal “1” to the mechanical brake operation control device 22 is provided.

  In this way, in the device that drives / stops the actuating bodies 2 and 3 by power running / regeneration of the motors 2m and 3m, the mechanical brake 23 is used when the regenerative brake function of the motors 2m and 3m breaks down (deteriorates function and deviates from the use range) Regenerative brake failure detection processing device that stops, and generally during power running (except when the device operates as a safety protection device), there is no safety problem due to failure other than runaway failure. Runaway failure determination processing device stopped by the brake 23, failure determination with temperature upper limit deviation departure discriminator 25, deceleration lower limit departure departure discriminator 28, acceleration upper limit deviation departure discriminator 31, etc. that detect a decrease in regeneration function And a processing circuit 21 including a mechanical brake operation control device 22 and a mechanical brake 23 of an electric motor.

  Next, an example of the regenerative brake failure handling function will be described with reference to the flowchart shown in FIG.

(Step S1)
The motor / inverter temperature sensor 24 detects the temperature of the motors 2 m and 3 m or their inverters 15.

(Step S2)
The temperature upper limit deviation discriminator 25 determines whether the temperature detected by the sensor has deviated beyond the set temperature upper limit.

(Step S3)
If the temperature upper limit deviation discriminator 25 determines that the detected temperature has risen beyond the set temperature upper limit, the motors 2m and 3m and the inverter 15 will be degraded and the regenerative current will not flow easily. Therefore, it is determined that the regenerative braking function has failed or lowered, and an ON signal “1” is output to the OR circuit 35.

(Step S4)
The OR circuit 35 outputs an ON signal “1” to the mechanical brake operation control device 22, and the mechanical brake operation control device 22 outputs an operation signal to the emergency electromagnetic brake of the electric motors 2 m and 3 m, and the electric motors 2 m and 3 m are connected. Force stop.

  Next, an example of an operation speed abnormality coping function will be described with reference to the flowchart shown in FIG.

(Step S5)
The speed detector 26 detects the operating speed of the operating bodies 2 and 3 operated by the electric motors 2m and 3m.

(Step S6)
The acceleration / deceleration calculator 27 calculates the acceleration or deceleration of the motors 2m, 3m or the operating bodies 2, 3 from the operating speed.

(Step S7)
Detects operation output output from operating devices (operating lever, etc.) in the cab.

(Step S8)
Calculate and set the deceleration lower limit and acceleration upper limit according to the operation output.

(Step S9)
The deceleration lower limit deviation discriminator 28 determines whether or not the deceleration calculated by the acceleration / deceleration calculation device 27 is below the deceleration lower limit set according to the operation output. If it is, it is determined that the regenerative braking function of the motors 2 m and 3 m and the inverter 15 has failed or is lowered, and an ON signal “1” is output to the OR circuit 35.

(Step S10)
The OR circuit 35 outputs an ON signal “1” to the mechanical brake operation control device 22, and the mechanical brake operation control device 22 outputs an operation signal to the mechanical brake 23 of the electric motors 2m and 3m, forcing the electric motors 2m and 3m. Stop.

(Step S11)
The acceleration upper limit deviation discriminator 31 determines whether or not the acceleration calculated by the acceleration / deceleration calculating device 27 exceeds the acceleration upper limit set according to the operation output.

  At this time, the acceleration upper limit deviation discriminator 31 is set according to the operation output even when the operation output (travel speed command value, turning speed command value) for operating the actuators 2 and 3 is smaller than the predetermined set value. When the acceleration deviating from the acceleration upper limit is determined (YES in step S11), it is determined that a runaway failure has occurred in the electric motors 2m and 3m for traveling or turning and the inverter 15, and the ON signal “1”. Is output from the OR circuit 35 to the mechanical brake operation control device 22.

  Similarly, when the component device failure detector 34 detects a failure of the devices constituting the motors 2 m, 3 m or the inverter 15 and outputs an ON signal “1”, the OR circuit 35 sends the mechanical brake operation control device 22 to the mechanical brake operation control device 22. Outputs mechanical brake operation signal.

  Next, the effect of this embodiment will be described.

  When the regenerative braking function of the electric motors 2m and 3m of the hybrid hydraulic excavator 1 fails, the mechanical brake operation control device 22 operates the mechanical brake 23 of the electric motors 2m and 3m by determining the failure of the regenerative braking function by the failure discriminator 20 Therefore, the electric motors 2m and 3m can be automatically and reliably stopped by the mechanical brake 23 that operates in response to a failure of the regenerative brake function. By automating the safety stop function, it becomes possible to perform normal deceleration operation only with the regenerative brake function while ensuring safety, and it is possible to contribute to an increase in efficiency by collecting regenerative energy.

  Provide a temperature upper limit deviation discriminator 25 that outputs an ON signal after determining that the temperature of the motor 2m, 3m or inverter 15 detected by the motor / inverter temperature sensor 24 has deviated from the set temperature upper limit. As a result, the usage conditions of the equipment can be limited to a certain range, and a stop function can be secured even during operation outside the usage conditions, so there is no need to increase the equipment capacity by unnecessarily tightening the usage conditions, and the equipment capacity can be rationalized. Can be set to a range.

  Mechanical brake operation control device from OR circuit 35 by ON signal “1” from at least one of temperature upper limit deviation discriminator 25, deceleration lower limit deviation discriminator 28 and failure detector 34 of failure discriminator 20 Since the ON signal “1” is output to 22, when the temperature of at least one of the motors 2 m and 3 m and the inverter 15 rises exceeding the set temperature upper limit, the operating body 2 that is operated by the motors 2 m and 3 m , 3 deceleration deviates from the set deceleration lower limit, and the motors 2m, 3m and motors 2m, 3m and motors that constitute the inverter 15 both fail. Can be automatically stopped by mechanical brake 23.

  Even when the operation output of the operating levers, etc., for operating the actuators 2 and 3 is smaller than the predetermined set value, the acceleration upper limit deviation discriminator 31 has deviated from the acceleration upper limit set according to the operation output. When the acceleration is discriminated, an ON signal “1” is output from the acceleration upper limit deviation discriminator 31 and an ON signal “1” is output from the OR circuit 35 to the mechanical brake operation control device 22. The motors 2m and 3m can be automatically stopped by the mechanical brake 23 by determining the runaway failure of the operating bodies 2 and 3 such as the turning system.

  In short, it is possible to determine the failure of the regenerative braking function of the motors 2m and 3m (degradation of function and deviation from the operating range), and to detect the failure that activates the mechanical brake 23 built into the motors 2m and 3m as an emergency electromagnetic brake. By incorporating it, runaway prevention can be realized without installing a separate brake system.

  In addition, there is no regenerative function in the method of hydraulically driving the operating bodies 2 and 3, and the hydraulic equipment is a braking system with a proven track record and no special failure detection processing device is provided. However, it is essential to ensure the stop function, but this method realizes the stop function in a simple and reliable manner.

  In particular, this system is a simple and reliable method in a system in which the regenerative brake function of the motors 2 m and 3 m is the main or only brake except the mechanical brake 23.

  In the above embodiment, the example applied to the hydraulic drive and electric drive hybrid hydraulic excavator 1 has been described. However, the present invention can also be applied to an electric drive work machine that does not use hydraulic pressure.

1 is a block diagram showing an embodiment of a motor failure stop device according to the present invention. It is the side view and circuit diagram of a hybrid type working machine in which the stop device same as the above is incorporated. It is a flowchart which shows an example of the regenerative brake failure countermeasure function of a stop apparatus same as the above. It is a flowchart which shows an example of the operation speed abnormality countermeasure function of a stop apparatus same as the above.

Explanation of symbols

1 Hybrid hydraulic excavator as a hybrid work machine
2,3 Actuator
2m, 3m electric motor
15 Inverter
20 Fault classifier
22 Mechanical brake operation control equipment
23 Mechanical brake
24 Electric motor / inverter temperature sensor as temperature sensor
25 Temperature upper limit deviation discriminator
26 Speed detector
28 Deceleration threshold limit deviation discriminator
31 Acceleration upper limit deviation discriminator
34 Component failure detector
35 OR circuit

Claims (5)

An electric motor having a mechanical brake and operating an operating body;
A failure discriminator for discriminating and processing a failure including a deterioration in the function of the regenerative braking function when using this motor as a generator;
An electric motor failure stop device comprising: a mechanical brake operation control device that operates a mechanical brake according to a failure determination by the failure determiner. The fault classifier
A temperature sensor that detects the temperature of at least one of the electric motor and an inverter that controls the electric motor;
The electric motor according to claim 1, further comprising: a temperature upper limit deviation discriminator that discriminates that the temperature detected by the temperature sensor has deviated from the set temperature upper limit and outputs an ON signal. Stop device in case of failure. The fault classifier
A speed detector for detecting an operating speed of either the electric motor or an operating body operated by the electric motor;
Set a deceleration lower limit limit according to the operation output to operate the operating body, and output an ON signal when it is determined that the deceleration calculated from the operating speed has deviated from the deceleration lower limit limit. A deviation discriminator;
A component failure detector that detects a failure of the device constituting the motor and the inverter and outputs an ON signal; and
An OR circuit that outputs an ON signal to a mechanical brake operation control device in response to an ON signal from at least one of a temperature upper limit deviation discriminator, a deceleration lower limit limit discriminator, and a component equipment failure detector. The stop device at the time of motor failure according to claim 2. The fault classifier
An acceleration upper limit deviation discriminator that sets an acceleration upper limit according to the operation output for operating the operating body, and outputs an ON signal when it is determined that the acceleration calculated from the operating speed has deviated from the acceleration upper limit. ,
An OR circuit that outputs an ON signal to a mechanical brake operation control device in response to an ON signal from at least one of a temperature upper limit deviation discriminator, a deceleration lower limit limit deviation discriminator, an acceleration upper limit deviation discriminator, and a component equipment failure detector. When,
The electric motor failure stop device according to claim 3, comprising: The electric motor failure stop device according to any one of claims 1 to 4, which is applied to an electric motor of a hybrid work machine.

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