JP4855337B2 - Fluid pressure device with brush wear detection device - Google Patents

Description

  The present invention relates to a fluid pressure device including a brush wear detection device for detecting the end of life of a brush included in a brush motor, and more particularly to a vehicle-mounted hydraulic device including a brush wear detection device.

  2. Description of the Related Art Conventionally, a brush motor in which electric power is supplied to a coil via a brush and a commutator and the rotor rotates has both excellent rotation characteristics and output efficiency. Therefore, it is one of electric power devices that convert electric energy into mechanical energy. As such, it is suitably used in various fluid pressure devices such as a vehicle-mounted hydraulic device.

  The brush motor includes a rotor that is rotated about its main shaft by the action of a rotational moment, and a stator that interacts with the rotor and generates a desired rotational moment. The brush motor also includes a brush and a commutator for supplying power to the rotor coil. Here, the brush and the commutator are in pressure contact with each other by an elastic member such as a spring in order to reliably supply electric power from the brush to the commutator. In such a brush motor, when electric power is supplied to the rotor coil via the brush and the commutator, a rotational moment is generated in the rotor due to the interaction with the stator. As a result, the rotor of the brush motor is rotated about its main axis.

  Hereinafter, the configuration of a conventional brush motor will be outlined with reference to the drawings.

  FIG. 7 is a cross-sectional view schematically showing a schematic configuration of a conventional brush motor. In FIG. 7, FIG. 7A shows a cross-sectional configuration along the line aa of the conventional brush motor, and FIG. 7B shows the line bb of the conventional brush motor. The structure of a cross section is shown.

  As shown in FIG. 7, a conventional brush motor 101 includes a rotor 101b that rotates about a cylindrical main shaft 101a, and a pair of stators 101c and 101c that generate a desired rotational moment in the rotor 101b. It is equipped with. Further, the conventional brush motor 101 shown in FIG. 7 includes a commutator 101d in which a plurality of electrodes are arranged in a cylindrical shape on the outer periphery of a main shaft 101a, and electrically connected to a coil included in the rotor 101b. And a pair of brushes 101e and 101e for supplying power to the commutator 101d. Here, as shown in FIG. 7, the pair of brushes 101e and 101e and the commutator 101d are pressed against each other by the pair of brushes 101e and 101e being pressed against the commutator 101d by the pair of springs 101f and 101f. ing. Thereby, in the brush motor 101, electric power is reliably supplied from the pair of brushes 101e and 101e to the commutator 101d.

  By the way, in such a conventional brush motor, since the commutator is rotated according to the rotation of the main shaft in a state where the brush and the commutator are pressed and contacted by an elastic member such as a spring, the brush is proportional to the operating time. Wear progresses. Here, the wear of the brush may cause a failure of the brush motor. In other words, when the brush reaches the end of its life, a fluid pressure device such as a vehicle-mounted hydraulic device equipped with a brush motor fails. Therefore, in order to properly operate a fluid pressure device such as a vehicle-mounted hydraulic device including a brush motor for a long period of time, it is desirable to appropriately detect the end of life of the brush included in the brush motor. However, the degree of wear of the brush greatly varies depending on the degree of load on the brush motor, the use environment conditions such as temperature and humidity, and the like. Therefore, conventionally, it has been difficult to easily detect the end of life of the brush provided in the brush motor. Note that disassembling the brush motor and visually checking the wear state of the brush in order to grasp the wear progress of the brush causes an increase in the maintenance cost of the fluid pressure device such as the in-vehicle hydraulic device.

  Therefore, a configuration has been proposed in which a brush wear state is detected by detecting a decrease in the insulation resistance value of the brush motor (see, for example, Patent Document 1).

In this proposed configuration, the wear powder generated by brush wear changes the insulation resistance value in the brush motor, and the wear resistance state of the brush is detected by measuring the insulation resistance value in the brush motor. . For example, when abrasion powder is generated due to brush wear, the generated abrasion powder adheres to the periphery of the brush and the commutator, and an electron movement path is formed between the brush and the commutator. The value drops. Therefore, in the proposed configuration, it is determined that the wear of the brush has progressed when the insulation resistance value in the brush motor falls below a predetermined threshold value. Thereby, grasping | ascertaining the wear state of the brush with which a brush motor is equipped, and the detection of the end of life are performed appropriately, without disassembling a brush motor regularly.
Japanese Patent Laid-Open No. 7-31100

  However, in the case of the conventional proposal, an insulation resistance meter is required to measure the insulation resistance value of the brush motor. Here, since this insulation resistance meter usually has a special configuration for accurately measuring a relatively high insulation resistance value, it is significantly more expensive than a general resistance meter. In addition, this insulation resistance meter requires periodic calibration in order to accurately measure the insulation resistance value over a long period of time. Therefore, when the conventional proposal is applied to a fluid pressure device such as an in-vehicle hydraulic device, the initial cost and the maintenance cost of the fluid pressure device such as the in-vehicle hydraulic device are significantly increased.

  In the case of the conventional proposal, in order to measure the insulation resistance value of the brush motor, it is necessary to electrically disconnect the brush motor from its drive circuit. That is, in the case of the above conventional proposal, it is necessary to remove the brush motor from the fluid pressure device such as a vehicle-mounted hydraulic device every time it is inspected. Therefore, when the conventional proposal is applied to a fluid pressure device such as a vehicle-mounted hydraulic device, the maintenance cost of the fluid pressure device such as the vehicle-mounted hydraulic device further increases.

  That is, the above-mentioned conventional proposals have not been able to sufficiently meet the recent strong demand for lower prices for hydraulic devices such as in-vehicle hydraulic devices.

  The present invention has been made in order to solve the above-described conventional problems, does not require expensive measuring equipment that requires maintenance, and reliably detects the end of the life of the brush without taking the trouble of disassembly and the like. An object of the present invention is to provide a vehicle-mounted hydraulic device including a brush wear detection device for a brush motor that can be used.

  When the brush of the brush motor is worn, the inventors of the present application deteriorate the contact state between the brush and the commutator, and a significant disturbance occurs in the current flowing through the brush motor (hereinafter referred to as “motor current”). Focusing on the remarkable increase in the temperature of the brush (hereinafter referred to as “brush temperature”), the configuration of the present invention has been completed.

  In order to solve the above-described problems, a fluid pressure device according to the present invention includes a power source that supplies power, a motor that is supplied with power from the power source via a brush and a commutator, and whose main shaft rotates, and the motor A fluid pump that pumps the working fluid by rotation of the main shaft, a power generator that generates power by the working fluid pumped from the fluid pump, and the working fluid that is pumped to the power generator A fluid pressure device comprising: a pressure limiter that restricts the pressure of the motor; and the fluid pressure device includes a detector that detects a predetermined physical quantity correlated with the rotation of the main shaft of the motor, and a brush of the motor. A brush wear detecting device for detecting the end of life, wherein the brush wear detecting device detects the pressure detected by the detector while the pressure is limited by the pressure limiter. Based on the comparison with the reference physical quantity corresponding to the constant physical quantity, and is configured to detect the life end of the brush of the electric motor.

  With such a configuration, the brush wear detection device detects the end of life of the brush of the motor based on a comparison between a predetermined physical quantity detected by the detector during pressure restriction by the pressure limiter and a corresponding reference physical quantity. To provide a fluid pressure device such as an in-vehicle hydraulic device that can reliably detect the end of the life of a brush without using expensive measuring equipment that requires maintenance and without troubles such as disassembly. It becomes possible.

  In this case, provided with a current sensor as the detector, the brush wear detection device based on a comparison between the motor current value as the predetermined physical quantity detected by the current sensor and the reference current value as the reference physical quantity, The end of life of the brush of the electric motor is detected.

  With such a configuration, the end of life of the brush of the electric motor is detected using a very inexpensive current sensor, so that a fluid pressure device such as an in-vehicle hydraulic device can be provided at a very low cost.

  In the above case, a current sensor as the detector is provided, and the brush wear detection device includes a motor current fluctuation range as the predetermined physical quantity detected by the current sensor and a reference current fluctuation range as the reference physical quantity. Based on the comparison, the end of life of the brush of the electric motor is detected.

  With this configuration, the end of life of the brush of the electric motor is detected based on the comparison between the motor current fluctuation range and the reference current fluctuation range as the reference physical quantity, so that it is possible to accurately detect the end of life of the brush.

  In this case, the brush wear detection device detects the end of life based on a comparison between the motor current fluctuation width and the reference current fluctuation width in a predetermined time.

  With such a configuration, the end of life of the brush is detected based on a comparison between the motor current fluctuation range and the reference current fluctuation range at a predetermined time, and thus it is possible to accurately detect the end of brush life in a short time.

  In the above case, a temperature sensor as the detector is provided, and the brush wear detection device is based on a comparison between the brush temperature as the predetermined physical quantity detected by the temperature sensor and the reference temperature as the reference physical quantity. The end of life of the brush of the electric motor is detected.

  With such a configuration, since the end of life of the brush of the motor is detected using a very inexpensive temperature sensor, it is possible to provide a fluid pressure device such as an in-vehicle hydraulic device at a very low cost.

  In this case, the brush wear detection device detects the end of life based on a comparison between the brush temperature and the reference temperature after a predetermined time has elapsed.

  With such a configuration, since the end of the life of the brush is detected based on the comparison between the brush temperature and the reference temperature after a predetermined time has elapsed, it is possible to detect the end of the life of the brush in a short time.

  In the above case, a temperature sensor as the detector is provided, and the brush wear detection device compares the brush temperature change as the predetermined physical quantity detected by the temperature sensor with the reference temperature change as the reference physical quantity. Based on the above, the end of life of the brush of the electric motor is detected.

  With such a configuration, the end of life of the brush of the electric motor is detected based on the comparison between the change in brush temperature and the change in reference temperature as a reference physical quantity, so that the end of life of the brush can be accurately detected.

  In this case, the brush wear detection device detects the end of life based on a comparison between the brush temperature change and the reference temperature change at a predetermined time.

  With such a configuration, since the end of the life of the brush is detected based on the comparison between the change in the brush temperature and the change in the reference temperature in a predetermined time, the end of the life of the brush can be detected in a short time.

  According to the configuration of the fluid pressure device according to the present invention, there is no need for expensive and maintenance equipment that requires maintenance, and the lifetime of the brush provided in the brush motor can be reduced at low cost without any trouble of disassembly and the like. It becomes possible to detect reliably. Therefore, according to the configuration of the fluid pressure device according to the present invention, it becomes possible to reliably detect the end of the life of the brush provided in the brush motor. It is possible to replace the brush provided. As a result, a fluid pressure device such as a vehicle-mounted fluid pressure device including a brush motor can be suitably used for a long period of time.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described in detail below with reference to the drawings.

(Embodiment 1)
Fig.1 (a) is a block diagram which shows typically the structure of the vehicle-mounted hydraulic apparatus provided with the brush abrasion detection apparatus based on Embodiment 1 of this invention. In FIG. 1A, only the components necessary for explaining the present invention are shown, and the other components are not shown.

  As shown in FIG. 1A, an in-vehicle hydraulic device 100a (for example, a tailgate lifter) according to the present embodiment supplies power to a power source 10 and a brush motor 30 described later from the power source 10. An intermittent switch 20, a brush motor 30 that is supplied with electric power from the power supply 10 through the switch 20 and whose rotor rotates, and a hydraulic oil tank 40 that is driven by a main shaft of the brush motor 30 to be described later. A hydraulic pump 50 that pumps the hydraulic oil 40a toward the actuator 70, a relief valve 60 that returns the hydraulic oil 40a pumped from the hydraulic pump 50 to the hydraulic oil tank 40 as necessary, and the relief valve 60. Actuator 70 is supplied with hydraulic oil 40a from hydraulic pump 50 that has not been returned to hydraulic oil tank 40, and converts mechanical energy into physical momentum. , And a. And as shown to Fig.1 (a), the vehicle-mounted hydraulic apparatus 100a which concerns on this Embodiment has the electric current sensor 80a which detects the electric current when the electric power is supplied to the brush motor 30 from the power supply 10, and A brush wear detection device 90 that detects the end of life of the brush included in the brush motor 30 based on the output voltage of the current sensor 80a is provided as a characteristic component.

  Hereinafter, the constituent elements of the in-vehicle hydraulic device 100a will be described in detail in order, and the power source 10 includes a storage battery (battery). As this storage battery, for example, an in-vehicle battery having an output voltage of 24V is disposed.

  The switch 20 is configured by a switch, a relay (relay), or the like. As this switch 20, for example, a mechanical or semiconductor switch, an electromagnetic relay, a semiconductor relay, or the like is disposed. Note that in a vehicle-mounted hydraulic device such as a general tailgate lifter, a mechanical switch that is appropriately operated manually by an operator is usually used.

  Although not shown in FIG. 1A, the brush motor 30 interacts with a rotor that is rotated about the main shaft by the action of a rotational moment, in the same manner as a conventional general brush motor. And a stator for generating a rotational moment. The brush motor 30 includes a brush and a commutator (not shown in FIG. 1A) for supplying power to a coil included in the rotor. Here, the brush and the commutator are in pressure contact with each other by an elastic member such as a spring in order to reliably supply electric power from the brush to the commutator as in the case of a conventional general brush motor. . Thereby, in the brush motor 30, the power supply from the brush to the commutator is reliably performed.

  The hydraulic oil tank 40 stores therein hydraulic oil 40a for operating the actuator 70. In consideration of the viscosity change due to the influence of the environmental temperature and the viscosity change due to the energy of the pressure loss in the hydraulic circuit, the hydraulic oil 40a is not affected by the movement performance of the actuator 70 and its positioning accuracy. Appropriate hydraulic fluid is selected.

  The hydraulic pump 50 converts the torque and speed of mechanical energy related to the rotational movement of the rotor of the brush motor 30 into the pressure and flow rate of the fluid energy of the hydraulic oil 40a. As this hydraulic pump 50, pumps, such as a gear pump and a screw pump, are arrange | positioned, for example. When the main shaft of the hydraulic pump 50 is rotationally driven by the main shaft of the brush motor 30, a liquid feeding member such as a gear connected to the main shaft of the hydraulic pump 50 is rotationally driven. The hydraulic oil 40 a is pumped toward the 70.

  The relief valve 60 is a so-called safety valve, and when the pressure of the hydraulic oil 40a in the pipe connecting the hydraulic pump 50 and the actuator 70 exceeds a predetermined pressure threshold value, the relief valve 60 is automatically opened, Excess hydraulic oil 40 a is automatically discharged from the pipe toward the hydraulic oil tank 40. That is, the relief valve 60 appropriately prevents the malfunction of the actuator 70 by preventing the hydraulic oil 40a from being supplied excessively toward the actuator 70 from the hydraulic oil tank 40. Note that the predetermined pressure threshold value set in the relief valve 60 is appropriately set in advance based on the specifications of the in-vehicle hydraulic device 100a. In addition, once this predetermined pressure threshold is set, it is not changed thereafter in order to ensure safety.

  When the hydraulic oil 50a is supplied from the hydraulic oil tank 40 by the hydraulic pump 50, the actuator 70 uses a mechanical energy of the hydraulic oil 40a to generate a physical motion such as an expansion / contraction motion or a bending / extension motion. . The actuator 70 raises and lowers the tailgate included in the vehicle by generating a physical movement such as an expansion / contraction movement or a bending / extension movement. The actuator 70 is appropriately selected based on the lifting specifications required for the in-vehicle hydraulic device 100a.

  On the other hand, the current sensor 80a, which is characteristically arranged in the present embodiment, is suitable in the vicinity of the wiring that electrically connects the power supply 10 and the brush motor 30 or through the wiring itself. It is arranged. Here, as the current sensor 80a, for example, a sensor such as a magnetic proportional sensor, a magnetic balance sensor, a magnetic coil sensor, or a coreless coil sensor is used. When electric power is supplied from the power source 10 to the brush motor 30, the current sensor 80 a converts the motor current flowing in the wiring that electrically connects the power source 10 and the brush motor 30 to a DC voltage proportional to the motor current. Output. Here, the current sensor 80a is appropriately selected according to the period (frequency) of disturbance of the motor current flowing through the brush motor 30 so as to reliably detect the disturbance of the motor current. As the current sensor 80a, an ammeter using a shunt resistor can be used. In this case, the ammeter measures the voltage difference between the shunt resistors connected in series between the power supply 10 and the brush motor 30, and outputs the measured voltage difference.

  Also, the brush wear detecting device 90 characteristically arranged in the present embodiment is based on the direct current detected by the current sensor 80a, and for example, the lower limit value of the direct current output from the current sensor 80a is a predetermined current threshold value. If it is less than, it is determined that the brush of the brush motor 30 has reached the end of its life, and that fact is transmitted to the operator via a display device such as a warning lamp.

  Hereinafter, the internal configuration of the brush wear detection device 90 according to the present embodiment will be described.

  FIG. 2 is a block diagram schematically showing an internal configuration of the brush wear detection apparatus according to Embodiment 1 of the present invention. FIG. 2A schematically shows a first internal configuration of the brush wear detection device. Moreover, FIG.2 (b) has shown typically the 2nd internal structure of the brush wear detection apparatus. In FIG. 2, only the components necessary for explaining the brush wear detecting device according to the present invention are shown, and the other components are not shown.

  In the present invention, as the internal configuration of the brush wear detecting device 90, the first internal configuration shown in FIG. 2 (a) may be applied, or the second internal configuration shown in FIG. 2 (b) is applied. May be. In any of the internal configurations, power for driving the components constituting them is supplied from the power supply 10 of the in-vehicle hydraulic device 100a.

  First, the first internal configuration of the brush wear detector 90 will be described.

  As shown in FIG. 2A, the first brush wear detection device 90a according to the present embodiment includes an A / D converter 91 that A / D converts a DC voltage value output from the current sensor 80a, and this A CPU 92 for detecting the end of the life of the brush included in the brush motor 30 based on the output of the A / D converter 91, the information stored in the memory 93, and the output of the timer 94, and a warning based on the output of the CPU 92. And a warning lamp 95 to be performed.

  Hereinafter, the components of the first brush wear detection device 90a will be described in detail in order. The A / D converter 91 samples a continuous analog value output from the current sensor 80a at a predetermined sampling period. The analog value is converted into a discrete digital value proportional to the analog value. Here, as the A / D converter 91, the disturbance of the motor current is ensured by sufficiently considering the rotation speed of the rotor provided in the brush motor 30 and the number of electrodes in the commutator provided in the brush motor 30. A / D converter having a detectable conversion time (or sampling period) is selected.

For example, assuming that the rotation speed of the rotor provided in the brush motor 30 is 3000 min ⁻¹ and the number of electrodes in the commutator provided in the brush motor 30 is 25, the frequency of disturbance of the motor current is about 1.25 kHz. Therefore, the period of disturbance of the motor current is expected to be about 800 μS.

  Therefore, in the present embodiment, an A / D converter having a conversion time of less than 800 μS, and preferably a conversion time of 100 μS or less is selected in order to reliably detect the disturbance of the motor current. An A / D converter having such a conversion time can be easily and very inexpensively obtained even if it is an A / D converter built in an inexpensive built-in microcomputer because the conversion time is 50 μS or less. Is possible. Depending on the number of rotations of the rotor provided in the brush motor 30 and the number of electrodes in the commutator provided in the brush motor 30, the period of disturbance of the motor current becomes very short. In this case, it is necessary to select an appropriate A / D converter having a conversion time capable of reliably detecting disturbance of the motor current.

  On the other hand, the CPU 92 determines whether the brush of the brush motor 30 has reached the end of its life based on the output of the A / D converter 91, the program stored in the memory 93 and the predetermined threshold value, and the output of the timer 94. Determine whether or not. When the CPU 92 determines that the brush of the brush motor 30 has reached the end of its life, it outputs a control signal for turning on the warning lamp 95. Here, as the CPU 92, a CPU having a clock frequency that can appropriately use the output of the A / D converter 91 is selected. Note that a CPU having such a clock frequency can be obtained easily and at a very low cost since the conversion time of the A / D converter 91 is about 100 μS even if the conversion time is short.

  The memory 93 stores a program necessary for detecting the end of the life of the brush provided in the brush motor 30 and a predetermined threshold value. Here, as the memory 93, since the data capacity of the program stored in the present embodiment and the predetermined threshold is relatively small, the type of the memory 93 is not particularly limited, and can be obtained easily and at a very low cost. Possible general-purpose memory can be used.

  The timer 94 counts the elapsed time when the CPU 92 determines whether or not the brush of the brush motor 30 has reached the end of its life. Here, as the timer 94, the elapsed time to be counted is about several seconds to several minutes, and since high accuracy is not required for the elapsed time to be counted, its configuration is not particularly limited, Any configuration of the timer is applicable. For example, the timer 94 may be configured by hardware, or may be configured by software.

  When the CPU 92 determines that the brush of the brush motor 30 has reached the end of its life and outputs a control signal for turning on the warning lamp 95, the warning lamp 95 notifies the operator by lighting or blinking the lamp based on the control signal. To warn. In the present embodiment, the warning lamp 95 performs a warning by lighting the lamp or the like. However, the present invention is not limited to such a form. For example, any warning form such as voice, buzzer sound, error message display, etc. may be adopted.

  Here, in the first brush wear detection device 90a shown in FIG. 2A, instead of the form in which the A / D converter 91, the CPU 92, the memory 93, the timer 94, and the like are individually arranged, their constituent elements It is even more desirable to adopt a form in which the microcomputer M having all of the above is disposed. Such microcomputers equipped with A / D converters, CPUs, memories, timers and the like are usually distributed at a very low cost. Therefore, with this configuration, the brush wear detection device 90a according to the present invention can be configured at a very low cost.

  Next, the second internal configuration of the brush wear detector 90 will be described.

  As shown in FIG. 2B, the second brush wear detecting device 90b according to the present embodiment divides the output voltage of the power source 10 to generate the reference voltage value Vstd, and the currents A comparator (an operational amplifier or a comparator) 97 for detecting the end of the life of the brush included in the brush motor 30 based on a comparison between the DC voltage value (detected current value) output from the sensor 80a and the reference voltage value Estd; And a warning lamp 95 that gives a warning based on the output of the comparator 97. In the second brush wear detection device 90b, the warning lamp 95 has the same configuration as the warning lamp 95 in the first brush wear detection device 90a.

  Hereinafter, the components of the second brush wear detection device 90b will be described in detail in order. The resistors 96a and 96b connected in series are connected in series between the output terminal of the power supply 10 and the ground (vehicle chassis). And the reference voltage value Vstd necessary for the comparator 97 to detect the end of the life of the brush is generated by dividing the output voltage value of the power supply 10. The resistors 96a and 96b are not particularly limited as long as they can simply divide the DC voltage value output from the power supply 10, and any type of resistors can be used. Is possible.

  On the other hand, the comparator 97 compares the DC voltage value output from the current sensor 80a with the reference voltage value Vstd generated by the resistors 96a and 96b. The comparator 97 turns on a warning lamp 95 when the brush of the brush motor 30 reaches the end of its life. Here, as in the case of selecting the A / D converter 91, the comparator 97 takes into consideration the number of rotations of the rotor provided in the brush motor 30 and the number of electrodes in the commutator provided in the brush motor 30. A comparator having a response time capable of reliably detecting disturbance of the motor current is selected. Note that a comparator having such a response time can be easily and very inexpensively obtained because the response time of a normal comparator is sufficiently short, about 1 μS. However, if the period of disturbance of the motor current becomes very short due to the number of rotations of the rotor provided in the brush motor 30 or the number of electrodes in the commutator provided in the brush motor 30, it should be taken into consideration It is necessary to select a suitable converter.

Hereinafter, a characteristic operation of the brush wear detection device 90 according to the present embodiment will be described.
In the following description, a mode in which the end of the life of the brush is detected based on the motor current of the brush motor 30 will be described. However, for convenience, the motor current or a corresponding voltage value (for example, the output voltage value of the current sensor 80a) is used. It will be described as a form based.

  FIG. 3 is an explanatory diagram for explaining a first principle for the brush wear detection device to detect the end of the life of the brush in the brush motor. FIG. 3A shows a change in the motor current with time before the brush reaches the end of its life. FIG. 3B shows a change with time of the motor current after the brush reaches the end of its life.

In FIG. 3, the DC voltage applied to the brush motor is set to 24V ± 5%, the motor current is set to about 80 A, and the motor current with time is set to about 3000 min ^−1. The change was measured at a sampling rate of 50 μs. In this measurement, the hydraulic pump is operated at a constant load by operating the relief valve by closing the hydraulic oil discharge port with a blind plug (hereinafter referred to as “relief state”). It adjusted so that it might become. A DC voltage was applied to the brush motor so that the rotor would rotate for 11 seconds and then stop for 70 seconds. The motor current was measured with a current probe in the immediate vicinity of the brush motor.

  As shown in FIG. 3A, before the brush motor reaches the end of its life, the value of the motor current in the relief state varies slightly depending on the contact state between the brush and the commutator. It changes at a substantially constant value within the range of a small fluctuation range a.

  On the other hand, as shown in FIG. 3B, after the brush of the brush motor has reached the end of its life, the value of the motor current in the relief state is affected by the deterioration of the contact state between the brush and the commutator, It fluctuates over time within a range of fluctuation width b that greatly exceeds fluctuation width a. For example, as shown in FIGS. 3A and 3B, the fluctuation range of the motor current before the end of the life is about 10 A, whereas the fluctuation range of the motor current after the end of the life is About 40A. When the brush of the brush motor approaches the end of its life, the brush current becomes rough and the contact state between the brush and the commuter deteriorates, causing an abnormal condition between the commuter and the brush. This is due to the occurrence of an arc.

  Therefore, in the present embodiment, the motor current in the relief state is detected at the time of inspection before starting work of the in-vehicle hydraulic device 100a, and the fluctuation range of the detected motor current value is greater than or equal to a predetermined fluctuation threshold. In this case, it is determined that the brush of the brush motor 30 has reached the end of its life. For example, when the motor current in the relief state is detected and the fluctuation range ΔId (average value) of the detected motor current value is equal to or greater than 16A, which is 20% of the rated current value 80A, the brush of the brush motor 30 has a life span. It is determined that the end has been reached.

  Alternatively, in the present embodiment, the motor current in the relief state is detected at the time of inspection before starting work of the in-vehicle hydraulic device 100a, and the upper limit value or lower limit value of the detected motor current value is a predetermined current threshold value. When it becomes above or below, it determines with the brush of the brush motor 30 having reached the end of life. For example, when the motor current in the relief state is detected, and the upper limit value (lower limit value) of the detected motor current value is equal to or greater than 96A which is + 20% of the rated current value 80A (−20% of the rated current value 80A) If it is 64 A or less), it is determined that the brush of the brush motor 30 has reached the end of its life.

  In the present embodiment, when the brush wear detection device 90 detects that the brush of the brush motor 30 has reached the end of its life, the operator takes out the brush motor 30 from the in-vehicle hydraulic device 100a, and the brush motor Replace 30 brushes. Note that the operator starts the operation of the in-vehicle hydraulic device 100a after replacing the brush of the brush motor 30.

  Hereinafter, a characteristic operation of the brush wear detection device 90 according to the present embodiment will be described.

  FIG. 4 is a flowchart specifically illustrating the characteristic operation of the brush wear detection apparatus according to the present embodiment. FIG. 4A illustrates a specific operation of the first brush wear detection device. FIG. 4B illustrates a specific operation of the second brush wear detection device. FIG. 4 shows characteristic steps for explaining the characteristic operation of the brush wear detecting device, and omits other general steps.

  As shown in FIG. 4 (a), the first brush wear detection device 90a starts with a relief when the operator performs a predetermined operation for detecting the end of the life of the brush in the brush motor 30 with the switch 20. Based on the output signal of the valve 60, the CPU 92 determines whether or not the relief valve 60 is in the relief state (step S1).

  If the CPU 92 determines that the relief valve 60 is not in the relief state (NO in step S1), the first brush wear detection device 90a continues to determine whether or not the relief valve 60 is in the relief state. To do.

  On the other hand, when the first brush wear detection device 90a determines that the state of the relief valve 60 is the relief state by the CPU 92 (YES in step S1), the output output from the current sensor 80a during a predetermined period in the relief state. After the voltage value is A / D converted by the A / D converter 91, the average value Iavg of the motor current value is calculated based on the converted output voltage value (step S2).

  Next, the first brush wear detection device 90a is based on the average current value Iavg and the reference current value IL (lower limit reference value) and reference current value IU (upper limit reference value) stored in the memory 93 in advance. Then, it is determined whether or not the average current value Iavg exceeds the reference current value IL and is lower than the reference current value IU (step S3). In the present embodiment, the reference current value IL is set to IL = 0.95In, for example, where In is the average value of normal motor currents in the relief state. Further, in the present embodiment, the reference current value IU is set as an average value of normal motor currents in the relief state, for example, IU = 1.05 In. That is, in this step S3, the first brush wear detection device 90a determines whether or not the average current value Iavg in a predetermined period is within the range of the average value In ± 5% of normal motor current.

  When the first brush wear detection device 90a determines that the average current value Iavg is equal to or less than the reference current value IL, or the average current value Iavg is equal to or greater than the reference current value IU (NO in step S3), the brush motor At 30, it is determined that a serious abnormality other than the end of the life of the brush has occurred, and a predetermined warning is given (step S4).

  On the other hand, if the first brush wear detection device 90a determines that the average current value Iavg exceeds the reference current value IL and is lower than the reference current value IU (YES in step S3), the brush motor 30 wears the brush. It is determined that no other serious abnormality has occurred, and detection of the motor current Id by the current sensor 80a is started (step S5).

  Next, the first brush wear detection device 90a measures the elapsed time Td from the start of the detection of the motor current Id by the timer 94, so that the elapsed time Td is stored in the memory 93 in advance. The CPU 92 determines whether or not Tstd (for example, 1 second) has been reached (step S6).

  If the first brush wear detection device 90a determines that the elapsed time Td has not reached the predetermined time threshold value Tstd (NO in step S6), whether or not the elapsed time Td has reached the predetermined time threshold value Tstd. Continue to determine.

  On the other hand, when the first brush wear detection device 90a determines that the elapsed time Td has reached the predetermined time threshold value Tstd (YES in step S6), the upper limit of the motor current value is based on the output voltage value of the current sensor 80a. After calculating the average value and the lower limit average value by the CPU 92, the CPU 92 further calculates a fluctuation range ΔId (average value) as a difference between the upper limit average value and the lower limit average value of the calculated motor current values (step S7). ).

  Then, the first brush wear detection device 90a calculates the motor current value based on the fluctuation range ΔId of the motor current value calculated in step S7 and the predetermined current fluctuation threshold value ΔIstd stored in the memory 93 in advance. The CPU 92 determines whether or not the fluctuation range ΔId is equal to or larger than a predetermined current fluctuation threshold ΔIstd (step S8).

  In the present embodiment, the predetermined current fluctuation threshold value ΔIstd is set, for example, as ΔIstd = 0.2 In, where In is the average value of normal motor currents in the relief state. Specifically, as described above, when the normal motor current in the relief state is 80 A, ΔIstd is set to 16 A, which is 20% of 80 A. The predetermined current fluctuation threshold value ΔIstd is appropriately set according to the performance of the brush motor 30 provided in the in-vehicle hydraulic device 100a.

  If the first brush wear detection device 90a determines that the fluctuation range ΔId of the motor current value is equal to or greater than the predetermined current fluctuation threshold ΔIstd (YES in step S8), the brush provided in the brush motor 30 has reached the end of its life. It is determined that it has been received, and a warning is given to the worker by the warning lamp 95 (step S4). If the first brush wear detecting device 90a determines that the fluctuation range ΔId of the motor current value is not equal to or greater than the predetermined current fluctuation threshold ΔIstd (NO in step S8), a series for detecting the end of the life of the brush. End the operation.

  On the other hand, as shown in FIG. 4B, the second brush wear detection device 90 b performs relief when the operator performs a predetermined operation for detecting the end of the life of the brush in the brush motor 30 with the switch 20. Based on the output voltage value Vd of the current sensor 80a in this state (in this case, the lower limit voltage value Vmin of the output voltage value Vd of the current sensor 80a) and the reference voltage value Vstd, the output voltage value Vd of the current sensor 80a becomes the reference voltage. It is determined by the comparator 97 whether or not it is equal to or less than the value Vstd (step S1). Alternatively, when the operator performs a predetermined operation for detecting the end of the life of the brush in the brush motor 30 by the switch 20, the second brush wear detection device 90b outputs the output voltage value Vd of the current sensor 80a in the relief state. (In this case, based on the upper limit voltage value Vmax of the output voltage value Vd of the current sensor 80a) and the reference voltage value Vstd, it is determined whether or not the output voltage value Vd of the current sensor 80a is equal to or higher than the reference voltage value Vstd. The determination is made by the comparator 97.

  In the present embodiment, the reference voltage value Vstd is set to a voltage value corresponding to a current value of + 20% (or −20%) of the rated current value in the relief state. For example, as described above, when the normal motor current in the relief state is 80 A, the reference voltage value Vstd is set to a voltage value corresponding to 96 A that is + 20% of the rated current value 80 A. Alternatively, the reference voltage value Vstd is set to a voltage value corresponding to 64 A that is −20% of the rated current value 80 A.

  When the second brush wear detection device 90b determines that the output voltage value Vd of the current sensor 80a is equal to or lower than the reference voltage value Vstd (YES in step S1), it determines that the brush of the brush motor 30 has reached the end of its life. Then, a warning is given to the worker by the warning lamp 95 (step S2). Alternatively, when the second brush wear detection device 90b determines that the output voltage value Vd of the current sensor 80a is greater than or equal to the reference voltage value Vstd, it determines that the brush of the brush motor 30 has reached the end of its life in the same manner. A warning lamp 95 warns the operator. If the second brush wear detecting device 90b determines in step S1 that the brush of the brush motor 30 has not yet reached the end of its life (NO in step S1; the lower limit voltage value Vmin of the output voltage value Vd corresponds to that). In the case where the reference voltage value Vstd is not less than or equal to the reference voltage value Vstd and the upper limit voltage value Vmax of the output voltage value Vd is not greater than or equal to the corresponding reference voltage value Vstd). End the operation.

  As described above, according to the configuration of the brush wear detection device 100a according to the present embodiment, it is determined whether or not the brush of the brush motor 30 has reached the end of its life by detecting the motor current of the brush motor 30 in the relief state. Therefore, no expensive measuring instrument such as an insulation resistance meter that requires maintenance is required, and it is possible to reliably detect the end of the life of the brush in the brush motor 30 without taking any troubles such as disassembly. . Thereby, in the in-vehicle hydraulic device 100a provided with the brush wear detecting device 90, it becomes possible to reliably detect the end of the life of the brush in the brush motor 30, so that the brush motor can be used at an appropriate time with the minimum necessary effort. It becomes possible to exchange 30 brushes. Therefore, according to the present embodiment, a fluid pressure device such as the in-vehicle hydraulic device 100a including the brush motor 30 can be suitably used for a long period of time.

(Embodiment 2)
FIG.1 (b) is a block diagram which shows typically the structure of the vehicle-mounted hydraulic apparatus provided with the brush abrasion detection apparatus which concerns on Embodiment 2 of this invention. In FIG. 1B, only the components necessary for explaining the present invention are shown, and the other components are not shown.

  The configuration of the in-vehicle hydraulic device 100b according to the present embodiment is the embodiment shown in FIG. 1A except that a temperature sensor 80b is provided instead of the current sensor 80a shown in FIG. 1 is the same as the configuration of the in-vehicle hydraulic device 100a according to the first embodiment. Therefore, in the following description, the description regarding the component similar to the component of the vehicle-mounted hydraulic apparatus 100a in the vehicle-mounted hydraulic apparatus 100b is abbreviate | omitted, and only the difference between both is demonstrated.

  As shown in FIG. 1B, the in-vehicle hydraulic device 100b according to the present embodiment operates in the same manner as in the first embodiment, with the power source 10, the switch 20, the brush motor 30, and the operation. An oil tank 40, a hydraulic pump 50, a relief valve 60, an actuator 70, and a brush wear detection device 90 are provided. However, as shown in FIG. 1B, the in-vehicle hydraulic device 100b according to the present embodiment is supplied with electric power from the power source 10 to the brush motor 30, and the brush is rotated when the rotor is driven to rotate. A temperature sensor 80b for detecting the temperature is provided instead of the current sensor 80a of the in-vehicle hydraulic device 100a.

  The temperature sensor 80 b that is characteristically disposed in the present embodiment is embedded in the vicinity of the brush in the brush motor 30 or in the brush of the brush motor 30. As the temperature sensor 80b, for example, a temperature measuring element that is generally easily available, such as a thermistor or a thermocouple, is provided. The temperature sensor 80b outputs a DC voltage proportional to the temperature of the brush provided in the brush motor 30 when electric power is supplied from the power source 10 to the brush motor 30 and the rotor is rotationally driven. Here, as the temperature sensor 80b, a temperature sensor having an appropriate response characteristic capable of accurately detecting a temperature change of the brush included in the brush motor 30 is selected according to a physical characteristic such as a heat capacity of the brush. . The temperature sensor 80b is disposed at an appropriate position where the temperature change of the brush can be accurately detected in consideration of the heat dissipation characteristics of the brush motor 30 and the like.

  In the present embodiment, the brush wear detecting device 90 is based on the output voltage value of the temperature sensor 80b, for example, the temperature change of the brush detected by the temperature sensor 80b (final temperature-initial temperature) is greater than or equal to a predetermined temperature threshold. In this case, it is determined that the brush of the brush motor 30 has reached the end of its life, and that fact is transmitted to the operator via a display device such as a warning lamp. Therefore, the hardware configuration of the brush wear detection device 90 according to the present embodiment is the same as the hardware configuration of the brush wear detection device 90 shown in the first embodiment. However, the software configuration of the brush wear detecting device 90 according to the present embodiment is different from that of the brush wear detecting device 90 shown in the first embodiment, based on the output voltage value of the temperature sensor 80b. It is configured to detect the end of life of the brush.

  Hereinafter, a characteristic operation of the brush wear detection apparatus according to the present embodiment will be described.

  FIG. 5A is an explanatory diagram for explaining a second principle for the brush wear detecting device to detect the end of the life of the brush in the brush motor. In FIG. 5A, a curve a shows the change in temperature of the brush at the beginning of the life of the brush over time, and a curve b shows the change in temperature of the brush at the end of the life of the brush over time.

In FIG. 5 (a), the DC voltage applied to the brush motor is set to 24V ± 5%, the motor current is set to about 80A, and the rotation speed of the rotor is set to about 3000 min ⁻¹ . The change over time is repeatedly measured at a sampling rate of 100 ms. In this measurement, similarly to the case of the first embodiment, the relief state is simulated and the load on the hydraulic pump is made constant. Further, a direct current voltage was periodically applied to the brush motor so that the rotor was rotated for 11 seconds and then stopped for 70 seconds. The temperature of the brush was measured by embedding a thermocouple as a temperature sensor inside the brush.

  As shown by the curve a in FIG. 5A, when the brush of the brush motor is at the beginning of its life, the temperature of the brush in the relief state slightly rises due to the influence of friction between the brush and the commutator. The degree of temperature rise in (11 seconds) is relatively mild.

  On the other hand, as shown by the curve b in FIG. 5A, when the brush of the brush motor reaches the end of its life, the temperature of the brush in the relief state is affected by the deterioration of the contact state between the brush and the commutator. And rises rapidly in one cycle. For example, as shown in FIG. 5A, in the first period, the rising temperature of the brush at the beginning of the life is about 50 ° C., whereas the rising temperature of the brush at the end of the life is about 90 ° C. As in the case of the first embodiment, when the brush reaches the end of its service life, the brush surface becomes rough and the contact state between the brush and the commuter deteriorates. This is due to the occurrence of an abnormal arc between the brush. This abnormal arc rapidly raises the temperature of the brush in a short period of time.

  Therefore, in the present embodiment, when the in-vehicle hydraulic device 100b is inspected before the start of work, the temperature of the brush is detected for a predetermined period in the relief state, and the temperature change of the brush detected in the predetermined period is a predetermined value. When the temperature is equal to or higher than the temperature threshold, it is determined that the brush of the brush motor 30 has reached the end of its life.

  FIG. 5B is an explanatory diagram for specifically explaining a technical configuration example for the brush wear detecting device to detect the end of the life of the brush in the brush motor. In FIG. 5B, a curve a indicates a change in control signal for rotationally driving the rotor of the brush motor over time. Curve b shows the temperature change of the brush over time.

  In the present embodiment, as shown by a curve a in FIG. 5B, the brush wear detection device 90 rotates the rotor of the brush motor 30 for 10 seconds, for example, in the relief state. During this time, the brush wear detection device 90 continuously detects the temperature of the brush provided in the brush motor 30 by the temperature sensor 80b. On the other hand, as shown by a curve b in FIG. 5B, when the rotor of the brush motor 30 is driven to rotate, the temperature of the brush rises with time. Therefore, in the present embodiment, the brush wear detection device 90 calculates the temperature change ΔTm of the brush in the relief state for 10 seconds. Then, the brush wear detection device 90 determines that the brush of the brush motor 30 has reached the end of its life when the calculated temperature change ΔTm is, for example, 70K or more. As in the case of the first embodiment, when the operator knows that the brush of the brush motor 30 has reached the end of its life, the operator takes out the brush motor 30 from the in-vehicle hydraulic device 100b and brushes the brush motor 30. Replace. Further, the operator starts the operation of the in-vehicle hydraulic device 100b after replacing the brush of the brush motor 30.

  FIG. 6 is a flowchart specifically illustrating the characteristic operation of the brush wear detecting apparatus according to the present embodiment. FIG. 6A illustrates a specific operation of the first brush wear detection device. FIG. 6B illustrates a specific operation of the second brush wear detection device. FIG. 6 shows characteristic steps for explaining the characteristic operation of the brush wear detection device, and omits other general steps.

  As shown in FIG. 6A, the first brush wear detecting device 90 a is configured such that when the brush is at a normal temperature, the operator performs a predetermined operation for detecting the end of the life of the brush in the brush motor 30 by the switch 20. First, based on the output signal of the relief valve 60, the CPU 92 determines whether or not the relief valve 60 is in the relief state (step S1).

  If the CPU 92 determines that the relief valve 60 is not in the relief state (NO in step S1), the first brush wear detection device 90a continues to determine whether or not the relief valve 60 is in the relief state. To do.

  On the other hand, when the first brush wear detection device 90a determines that the state of the relief valve 60 is the relief state by the CPU 92 (YES in step S1), based on the output voltage value output from the temperature sensor 80b in the relief state, An initial temperature Tm1 of the brush provided in the brush motor 30 is detected (step S2).

  Next, the first brush wear detection device 90a starts driving the brush motor 30 by controlling so that predetermined power is supplied from the power source 10 toward the brush motor 30 (step S3).

  Next, the first brush wear detection device 90a measures the elapsed time Td from the start of driving of the brush motor 30 by the timer 94, so that the elapsed time Td is stored in the memory 93 in advance. The CPU 92 determines whether or not Tstd (for example, 10 seconds) has been reached (step S4).

  If the first brush wear detection device 90a determines that the elapsed time Td has not reached the predetermined time threshold value Tstd (NO in step S4), whether or not the elapsed time Td has reached the predetermined time threshold value Tstd. Continue to determine.

  On the other hand, when the first brush wear detection device 90a determines that the elapsed time Td has reached the predetermined time threshold value Tstd (YES in step S4), the brush motor 30 detects that the brush motor 30 is based on the output voltage value output from the temperature sensor 80b. The latter stage temperature Tm2 of the brush provided is detected (step S5).

  Next, the first brush wear detection device 90a determines the detected late brush temperature Tm2 based on the initial brush temperature Tm1 detected in step S2 and the late brush temperature Tm2 detected in step S5. The CPU 92 calculates a temperature change ΔTm as a difference from the initial temperature Tm1 (step S6).

  Then, the first brush wear detecting device 90a determines that the brush temperature change ΔTm is a predetermined value based on the brush temperature change ΔTm calculated in step S6 and the predetermined temperature change threshold value ΔTmstd stored in the memory 93 in advance. The CPU 92 determines whether or not the temperature change threshold is greater than or equal to ΔTmstd (step S7).

  In the present embodiment, the predetermined temperature change threshold ΔTmstd is appropriately determined based on the temperature change of the brush at a predetermined time (10 seconds in the present embodiment) when the brush of the brush motor 30 reaches the end of its life. Is set. Specifically, in the present embodiment, a predetermined temperature change threshold ΔTmstd is set to 70K (Kelvin). The predetermined temperature change threshold ΔTmstd is appropriately set according to the performance of the brush motor 30 provided in the in-vehicle hydraulic device 100a, as in the first embodiment.

  When the first brush wear detection device 90a determines that the temperature change ΔTm of the brush is equal to or greater than the predetermined temperature change threshold ΔTmstd (YES in step S7), it determines that the brush provided in the brush motor 30 has reached the end of its life. Then, a warning is given to the worker by the warning lamp 95 (step S8). If the first brush wear detection device 90a determines that the temperature change ΔTm of the brush is not equal to or greater than the predetermined temperature change threshold value ΔTmstd (NO in step S7), a series of operations for detecting the end of the life of the brush are performed. finish.

  On the other hand, as shown in FIG. 6B, when the second brush wear detecting device 90b determines that the elapsed time Td has reached a predetermined time threshold value Tstd (YES in step S1), the temperature sensor 80b in the relief state. Based on the output voltage value Vd and the reference voltage value Vstd, the comparator 97 determines whether or not the output voltage value Vd of the temperature sensor 80b is equal to or higher than the reference voltage value Vstd (step S2).

  In the present embodiment, the reference voltage value Vstd is set to a voltage value corresponding to the brush rising temperature during a predetermined time (10 seconds in the present embodiment) when the brush of the brush motor 30 reaches the end of its life. Is done. For example, when the rising temperature of the brush at a predetermined time is 70K and the air temperature at that time is 30 ° C., the reference voltage value Vstd is set to a voltage value corresponding to 100 ° C.

  When the second brush wear detection device 90b determines that the output voltage value Vd of the temperature sensor 80b is equal to or higher than the reference voltage value Vstd (YES in step S2), it determines that the brush of the brush motor 30 has reached the end of its life. Then, a warning is given to the worker by the warning lamp 95 (step S3). If the second brush wear detecting device 90b determines that the brush of the brush motor 30 has not yet reached the end of its life (NO in step S2), the series of operations for detecting the end of the life of the brush is terminated. To do.

  Such an embodiment based on the brush temperature after a predetermined time has elapsed is a particularly effective form in an area where the annual temperature change is relatively small.

  In the present embodiment, the temperature sensor 80b detects the temperature change at a predetermined time of the brush provided in the brush motor 30 or the absolute temperature after the predetermined time of the brush provided in the brush motor 30 has elapsed. Although the form which detects the lifetime of a brush based on this is illustrated, it is not limited to such a form. For example, an ON / OFF switch such as a bimetal switch may be used. In this case, a bimetal switch that becomes conductive at a specified temperature (for example, 100 ° C.) is disposed in the vicinity of the brush included in the brush motor 30. When the brush of the brush motor 30 is in the normal temperature state, the brush motor 30 is driven for a specified time (for example, 10 seconds) in the relief state. And when a bimetal switch will be in a conduction | electrical_connection state, it is good also as a form by which electric power is supplied from the power supply 10 via this bimetal switch, and the warning lamp 95 lights. According to such a form, since it is not necessary to configure an electronic circuit, the brush wear detecting device 90 can be configured most inexpensively.

  As described above, according to the configuration of the brush wear detection device 100b according to the present embodiment, it is determined whether or not the brush of the brush motor 30 has reached the end of its life by detecting the brush temperature of the brush motor 30 in the relief state. Therefore, no expensive measuring instrument such as an insulation resistance meter that requires maintenance is required, and it is possible to reliably detect the end of the life of the brush in the brush motor 30 without taking any troubles such as disassembly. . Therefore, also according to the present embodiment, in the in-vehicle hydraulic device 100b including the brush wear detection device 90, it is possible to replace the brush of the brush motor 30 at a suitable time with the minimum necessary effort. Therefore, also according to this embodiment, it is possible to suitably use a fluid pressure device such as the in-vehicle hydraulic device 100b including the brush motor 30 for a long period of time.

  Other points are the same as those in the first embodiment.

  The in-vehicle hydraulic device provided with the brush wear detection device according to the present invention is a brush motor brush wear detection device that does not require expensive measuring equipment and can detect the wear of the brush without taking the trouble of disassembly and the like. As an in-vehicle hydraulic device, it has sufficient industrial applicability.

Fig.1 (a) is a block diagram which shows typically the structure of the vehicle-mounted hydraulic apparatus provided with the brush abrasion detection apparatus based on Embodiment 1 of this invention. Moreover, FIG.1 (b) is a block diagram which shows typically the structure of the vehicle-mounted hydraulic apparatus provided with the brush wear detection apparatus based on Embodiment 2 of this invention. FIG. 2 is a block diagram schematically showing an internal configuration of the brush wear detection apparatus according to Embodiment 1 of the present invention. FIG. 3 is an explanatory diagram for explaining a first principle for the brush wear detection device to detect the end of the life of the brush in the brush motor. FIG. 4 is a flowchart specifically illustrating the characteristic operation of the brush wear detection apparatus according to the present embodiment. FIG. 5A is an explanatory diagram for explaining a second principle for the brush wear detecting device to detect the end of the life of the brush in the brush motor. FIG. 5B is an explanatory diagram for specifically explaining a technical configuration example for the brush wear detecting device to detect the end of the life of the brush in the brush motor. FIG. 6 is a flowchart specifically illustrating the characteristic operation of the brush wear detecting apparatus according to the present embodiment. FIG. 7 is a cross-sectional view schematically showing a schematic configuration of a conventional brush motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Power supply 20 Switch 30 Brush motor 40 Hydraulic oil tank 40a Hydraulic oil 50 Hydraulic pump 60 Relief valve 70 Actuator 80a Current sensor 80b Temperature sensor 90 Brush wear detection apparatus 90a 1st brush wear detection apparatus 90b 2nd brush wear detection Device 91 A / D converter 92 CPU
93 Memory 94 Timer 95 Warning lamp 96a, 96b Resistor 97 Comparator 100a, 100b In-vehicle hydraulic device 101 Brush motor 101a Spindle 101b Rotor 101c Stator 101d Commutator 101e Brush 101f Spring M Microcomputer

Claims (8)

A power supply for supplying power;
An electric motor that is supplied with electric power from the power source via a brush and a commutator and rotates its spindle;
A fluid pump that pumps the working fluid by rotation of the main shaft of the motor;
A power generator that generates power by the working fluid pumped from the fluid pump;
A fluid pressure device comprising: a pressure limiter that limits a pressure of the working fluid pumped to the power generator;
The fluid pressure device includes:
A detector for detecting a predetermined physical quantity having a correlation with the rotation of the main shaft of the electric motor;
A brush wear detecting device for detecting the end of life of the brush of the electric motor,
The brush wear detection device detects the end of life of the brush of the electric motor based on a comparison between the predetermined physical quantity detected by the detector and a reference physical quantity corresponding thereto while the pressure is limited by the pressure limiter. A fluid pressure device configured to: A current sensor as the detector;
The brush wear detection device detects the end of life of the brush of the electric motor based on a comparison between a motor current value as the predetermined physical quantity detected by the current sensor and a reference current value as the reference physical quantity. The fluid pressure device according to 1. A current sensor as the detector;
The brush wear detection device detects the end of life of the brush of the motor based on a comparison between a motor current fluctuation range as the predetermined physical quantity detected by the current sensor and a reference current fluctuation range as the reference physical quantity. The fluid pressure device according to claim 1.   The fluid pressure device according to claim 3, wherein the brush wear detection device detects the end of life based on a comparison between the motor current fluctuation range and the reference current fluctuation range in a predetermined time. A temperature sensor as the detector;
The brush wear detection device detects the end of life of the brush of the electric motor based on a comparison between a brush temperature as the predetermined physical quantity detected by the temperature sensor and a reference temperature as the reference physical quantity. Fluid pressure device.   The fluid pressure device according to claim 5, wherein the brush wear detection device detects the end of life based on a comparison between the brush temperature and the reference temperature after a predetermined time has elapsed. A temperature sensor as the detector;
The brush wear detection device detects the end of life of the brush of the electric motor based on a comparison between a change in brush temperature as the predetermined physical quantity detected by the temperature sensor and a change in reference temperature as the reference physical quantity. The fluid pressure device according to 1.   The fluid pressure device according to claim 7, wherein the brush wear detection device detects the end of life based on a comparison between the brush temperature change and the reference temperature change at a predetermined time.

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