Life span determination device

Abstract

To provide a service life determination device that can determine the service life of a brush motor without installing a current sensor.SOLUTION: An ECU 4 is configured to determine the service life of a brush motor 22 being a power source of an oil pump. The ECU 4 estimates the motor current for the brush motor 22 on the basis of the oil temperature and oil pressure. The ECU 4 measures the operation time of the brush motor 22 at the estimated motor current. The ECU 4 determines the service life of the brush motor 22 on the basis of the estimated motor current and measured operation time.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a lifespan determination device. Place Regarding. [Background technology]

[0002] BACKGROUND ART A lifespan determination device for determining the lifespan of a brush motor is known (see, for example, Patent Document 1).

[0003] The life determination device is configured to determine the life of the brush motor based on the motor current. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-118787 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, the above-mentioned conventional lifespan determination device needs to be provided with a current sensor for measuring the motor current.

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a lifespan determination device and a lifespan determination method that can determine the lifespan of a brush motor without providing a current sensor. [Means for solving the problem]

[0007] The lifespan determination device according to the present invention is a lifespan determination device for determining the lifespan of a brush motor that is a power source of a fluid supply device, and is configured to determine the lifespan of the brush motor based on the temperature and pressure of the fluid. a memory unit that stores a map for deriving a current using the parameters, and a current estimation unit that estimates a current of the brush motor; an operation time measurement unit that measures an operation time of the brush motor at the current estimated by the current estimation unit; Record A lifespan determination unit is provided to determine the lifespan of the rotational motor. The current in the map is set to decrease as the temperature of the map increases, and the current in the map is set to increase as the pressure of the map increases; operation history information is stored in the memory unit, and the operation history information stores the operation time of the brush motor at each current in the map; and the life determination unit calculates a current squared time product using the operation time at each current stored in the operation history information, and determines that the life of the brush motor has expired when the current squared time product exceeds a threshold value. do.

[0008] In this way, by estimating the current of the brush motor based on the temperature and pressure of the fluid, it is possible to determine the life of the brush motor without providing a current sensor.

[0011] In the lifespan determination device, the supply device may be configured to supply fluid to an actuator of a vehicle height adjustment system. [Effects of the Invention]

[0013] The lifespan determination device of the present invention Place This makes it possible to determine the life of the brush motor without providing a current sensor. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing the configuration of a vehicle height adjustment system according to an embodiment of the present invention; [Figure 2] 2 is a block diagram showing an ECU of the vehicle height adjusting system of FIG. 1. FIG. [Figure 3] FIG. 3 is a diagram showing an example of a map of the ECU in FIG. 2. [Figure 4] 3 is a diagram showing an example of operation history information of the ECU of FIG. 2. FIG. [Figure 5] 3 is a flowchart for explaining the operation of storing the operation history of the brush motor by the ECU of FIG. 2. [Figure 6] 3 is a flowchart for explaining the operation of determining the life span of the brush motor by the ECU of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described below.

[0016] First, the configuration of a vehicle height control system 100 to which an ECU 4 according to an embodiment of the present invention is applied will be described.

[0017] The vehicle height adjustment system 100 is configured to adjust the height position of a vehicle body (not shown) relative to the wheels of the vehicle. As shown in Fig. 1, the wheels include a left front wheel 50FL, a right front wheel 50FR, a left rear wheel 50RL, and a right rear wheel 50RR. The front wheel 50FL is rotatably held by a front wheel holding member 51FL, the front wheel 50FR is rotatably held by a front wheel holding member 51FR, the rear wheel 50RL is rotatably held by a rear wheel holding member 51RL, and the rear wheel 50RR is rotatably held by a rear wheel holding member 51RR.

[0018] The vehicle height adjustment system 100 includes four hydraulic cylinders 1, a hydraulic oil supply / discharge device 2, a hydraulic circuit 3, and an ECU 4 (see FIG. 2). The four hydraulic cylinders 1 include hydraulic cylinders 1FL, 1FR, 1RL, and 1RR. The hydraulic cylinders 1FL, 1FR, 1RL, and 1RR are an example of the "actuator" of the present invention. The ECU 4 is an example of the "lifespan determination device" of the present invention.

[0019] The hydraulic cylinder 1FL is provided between the front wheel holding member 51FL and the vehicle body. The hydraulic cylinder 1FL functions as a shock absorber. The hydraulic cylinder 1FL is configured to be able to adjust the distance between the front wheel holding member 51FL and the vehicle body by expanding and contracting. A suspension spring (not shown) is provided in parallel with the hydraulic cylinder 1FL between the front wheel holding member 51FL and the vehicle body.

[0020] Specifically, the hydraulic cylinder 1FL includes a housing 11, a piston 12, and a piston rod 13. The housing 11 has an internal space, and the piston 12 is movably accommodated in the internal space, and the piston rod 13 is connected to the piston 12. The housing 11 is connected to the front wheel holding member 51FL, and the piston rod 13 is connected to the vehicle body. The internal space of the housing 11 is partitioned by the piston 12, and oil chambers 14 and 15 are formed. A communication passage 16 is formed in the piston 12, and the oil chambers 14 and 15 are connected to each other by the communication passage 16. A throttle is provided in the communication passage 16. Therefore, the hydraulic cylinder 1FL is configured to generate a damping force according to the moving speed of the piston 12 relative to the housing 11.

[0021] The hydraulic cylinder 1FR is provided between the front wheel holding member 51FR and the vehicle body. The hydraulic cylinder 1RL is provided between the rear wheel holding member 51RL and the vehicle body. The hydraulic cylinder 1RR is provided between the rear wheel holding member 51RR and the vehicle body. Other configurations of the hydraulic cylinders 1FR, 1RL, and 1RR are the same as those of the hydraulic cylinder 1FL described above.

[0022] The hydraulic oil supply / discharge device 2 is provided to supply and discharge hydraulic oil to the four hydraulic cylinders 1 via the hydraulic circuit 3. The hydraulic oil supply / discharge device 2 includes an oil pump 21, a brush motor 22, a reservoir tank 23, a check valve 24, and a return valve 25. The oil pump 21 is an example of a "supply device" in the present invention, and the hydraulic oil is an example of a "fluid" in the present invention.

[0023] Hydraulic oil is stored in a reservoir tank 23. The oil pump 21 is provided to pump up the hydraulic oil from the reservoir tank 23 and supply it to a common passage 31 (described later) of the hydraulic circuit 3. The brush motor 22 is the power source for the oil pump 21 and is provided to operate the oil pump 21. The brush motor 22 is a motor that operates mechanically using brushes and a commutator. The check valve 24 and return valve 25 are arranged in parallel on the discharge port side of the oil pump 21.

[0024] The check valve 24 is configured to allow hydraulic oil to flow from the oil pump 21 toward the common passage 31, and to block hydraulic oil from flowing from the common passage 31 toward the oil pump 21. The return valve 25 is provided to switch between supplying hydraulic oil from the oil pump 21 to the common passage 31 and discharging hydraulic oil from the common passage 31 to the reservoir tank 23. Specifically, when the oil pump 21 is stopped, the return valve 25 blocks the connection between the discharge port side of the oil pump 21 and the common passage 31, and connects the common passage 31 to the reservoir tank 23 side. On the other hand, when the oil pump 21 is operating, the return valve 25 blocks the connection between the reservoir tank 23 side and the common passage 31, and connects the common passage 31 to the discharge port side of the oil pump 21.

[0025] The hydraulic circuit 3 is provided between the four hydraulic cylinders 1 and the hydraulic oil supply / discharge device 2. The hydraulic circuit 3 includes a common passage 31, four individual passages 32, and four vehicle height adjustment valves 33. The four individual passages 32 include individual passages 32FL, 32FR, 32RL, and 32RR. The four vehicle height adjustment valves 33 include vehicle height adjustment valves 33FL, 33FR, 33RL, and 33RR.

[0026] The common passage 31 is disposed between the hydraulic oil supply / discharge device 2 and the four individual passages 32. That is, the common passage 31 is connected to the hydraulic oil supply / discharge device 2, and is branched into the four individual passages 32. A temperature sensor 34 and a pressure sensor 35 are provided in the common passage 31.

[0027] The individual passage 32FL is provided to connect the hydraulic cylinder 1FL to the common passage 31. A height adjustment valve 33FL is provided in the individual passage 32FL. The height adjustment valve 33FL is, for example, a normally closed electromagnetic on-off valve, and is provided to connect or disconnect the hydraulic cylinder 1FL to the common passage 31. The height adjustment valve 33FL is configured to open when hydraulic oil is supplied to or discharged from the hydraulic cylinder 1FL.

[0028] The individual passage 32FR is provided to connect the hydraulic cylinder 1FR to the common passage 31. A height adjustment valve 33FR is provided in the individual passage 32FR. The height adjustment valve 33FR is, for example, a normally closed electromagnetic on-off valve, and is provided to connect or disconnect the hydraulic cylinder 1FR to the common passage 31. The height adjustment valve 33FR is configured to open when hydraulic oil is supplied to or discharged from the hydraulic cylinder 1FR.

[0029] The individual passage 32RL is provided to connect the hydraulic cylinder 1RL to the common passage 31. A height adjustment valve 33RL is provided in the individual passage 32RL. The height adjustment valve 33RL is, for example, a normally closed electromagnetic on-off valve, and is provided to connect or disconnect the hydraulic cylinder 1RL to the common passage 31. The height adjustment valve 33RL is configured to open when hydraulic oil is supplied to or discharged from the hydraulic cylinder 1RL.

[0030] The individual passage 32RR is provided to connect the hydraulic cylinder 1RR to the common passage 31. A height adjustment valve 33RR is provided in the individual passage 32RR. The height adjustment valve 33RR is, for example, a normally closed electromagnetic on-off valve, and is provided to connect or disconnect the hydraulic cylinder 1RR to the common passage 31. The height adjustment valve 33RR is configured to open when hydraulic oil is supplied to or discharged from the hydraulic cylinder 1RR.

[0031] 2, the ECU 4 includes a calculation unit 41, a storage unit 42, and an input / output unit 43. The storage unit 42 stores programs for controlling the vehicle height adjustment system 100, etc. The calculation unit 41 is configured to control the vehicle height adjustment system 100 by executing the programs stored in the storage unit 42. The input / output unit 43 is connected to the temperature sensor 34, the pressure sensor 35, a vehicle height sensor (not shown), the brush motor 22, the four vehicle height adjustment valves 33, etc.

[0032] The temperature sensor 34 is provided to detect the temperature (oil temperature) of the hydraulic oil in the common passage 31. The pressure sensor 35 is provided to detect the pressure (oil pressure) of the hydraulic oil in the common passage 31. The vehicle height sensor is provided to detect the distance between the wheels and the vehicle body. The ECU 4 is configured to control the brush motor 22 and the four vehicle height adjustment valves 33 based on inputs from the vehicle height sensor and the like.

[0033] -Vehicle height adjustment operation- Next, an example of the operation of the vehicle height adjustment system 100 to raise or lower the vehicle height will be described.

[0034] [When vehicle height is increased] When the vehicle height is to be increased, the ECU 4 drives the brush motor 22 to operate the oil pump 21 and opens the four vehicle height adjustment valves 33. As a result, the hydraulic oil discharged from the oil pump 21 is supplied to the four hydraulic cylinders 1 via the hydraulic circuit 3. This causes the four hydraulic cylinders 1 to extend, increasing the vehicle height. Thereafter, when the vehicle height reaches a target value, the ECU 4 closes the four vehicle height adjustment valves 33 and stops the operation of the oil pump 21.

[0035] [When vehicle height is lowered] When the vehicle height is to be lowered, the ECU 4 opens the four vehicle height adjustment valves 33 while keeping the oil pump 21 stopped. As a result, the hydraulic oil in the four hydraulic cylinders 1 is returned to the reservoir tank 23 via the hydraulic circuit 3 and the return valve 25. This causes the four hydraulic cylinders 1 to contract, lowering the vehicle height. Thereafter, when the vehicle height reaches the target value, the ECU 4 closes the four vehicle height adjustment valves 33.

[0036] - Brush motor lifespan determination - When the brush motor 22 is in operation, the brushes slide and wear, which causes the brushes to easily deteriorate in the brush motor 22. Therefore, the ECU 4 is configured to estimate the degree of deterioration of the brushes and determine the life of the brush motor 22.

[0037] The ECU 4 is configured to estimate the current (motor current) of the brush motor 22 based on the detection results of the temperature sensor 34 and the pressure sensor 35. The ECU 4 is also configured to measure the operating time of the brush motor 22 at the estimated motor current. The ECU 4 is also configured to determine the life of the brush motor 22 based on the estimated motor current and the operating time at that motor current. The "current estimation unit," "operating time measurement unit," and "life determination unit" of the present invention are realized by the calculation unit 41 executing the program stored in the storage unit 42.

[0038] Specifically, a map 42a and operation history information 42b are stored in the storage unit 42 of the ECU 4. The map 42a is used to derive the motor current using the oil temperature and oil pressure as parameters. That is, the ECU 4 is configured to estimate the motor current using the map 42a. The map 42a is created in advance through experiments, simulations, etc.

[0039] 3, the parameter for oil temperature T is set in three stages, and the parameter for oil pressure P is set in four stages, allowing twelve patterns of motor current MC to be estimated. For example, when oil temperature T is less than threshold value Tta and oil pressure P is less than threshold value Pta, motor current MCaa is set.

[0040] Map 42a is set so that motor current MC decreases as oil temperature T increases. Therefore, for example, motor current MCab is smaller than motor current MCaa, and motor current MCac is smaller than motor current MCab. Map 42a is also set so that motor current MC increases as oil pressure P increases. Therefore, for example, motor current MCba is larger than motor current MCaa, motor current MCca is larger than motor current MCba, and motor current MCda is larger than motor current MCca. Therefore, in map 42a, motor current MCda is the largest and motor current MCac is the smallest.

[0041] 4, the operation history information 42b stores the operation time OT of the brush motor 22 at each motor current MC. For example, the operation history information 42b includes the operation time OTaa at the motor current MCaa. The operation time OT is accumulated by the ECU 4 when the brush motor 22 is driven.

[0042] Then, the ECU 4 calculates the current squared time product I using the operation time OT at each motor current MC stored in the operation history information 42b. 2 It is configured to calculate the current squared time product I 2 t is calculated using the following formula (1):

[0043]

number

[0044] In addition, the ECU 4 calculates the current squared time product I 2 When t exceeds a threshold value, it is determined that the life of the brush motor 22 has expired. This threshold value is a value that is set in advance based on experiments, simulations, and the like.

[0045] [Accumulation of operation history] Next, the operation of the ECU 4 to accumulate the operation history of the brush motor 22 will be described with reference to FIG.

[0046] First, in step ST1 of Fig. 5, the ECU 4 determines whether the brush motor 22 has been started. For example, the brush motor 22 is started when the vehicle height raising operation is started. If the ECU 4 determines that the brush motor 22 has been started, the process proceeds to step ST2. On the other hand, if the ECU 4 determines that the brush motor 22 has not been started, step ST1 is repeated. That is, the process waits until the brush motor 22 is started.

[0047] Next, in step ST2, the ECU 4 acquires the oil temperature and oil pressure using the temperature sensor 34 and the pressure sensor 35. The oil temperature is the temperature of the hydraulic oil in the common passage 31, and the oil pressure is the pressure of the hydraulic oil in the common passage 31. Then, in step ST3, the ECU 4 estimates the motor current using the map 42a. This estimation is performed based on the oil temperature and oil pressure acquired in step ST2.

[0048] Next, in step ST4, the ECU 4 measures the operating time at the estimated motor current.

[0049] Next, in step ST5, the ECU 4 acquires the oil temperature and oil pressure using the temperature sensor 34 and the pressure sensor 35. Then, in step ST6, the ECU 4 estimates the motor current using the map 42a. This estimation is performed based on the oil temperature and oil pressure acquired in step ST5.

[0050] Next, in step ST7, the ECU 4 determines whether the estimated motor current has transitioned. That is, the ECU 4 determines whether the motor current estimated in step ST6 has changed from the motor current previously estimated. If the ECU 4 determines that the motor current has transitioned, the process proceeds to step ST8. On the other hand, if the ECU 4 determines that the motor current has not transitioned, the process proceeds to step ST9.

[0051] In step ST8, the ECU 4 accumulates the operating time at the motor current before the transition. That is, the operating time measured in step ST4 is added to the operating time of the corresponding motor current in the operation history information 42b. For example, when the motor current transitions from MCaa to MCba, if the motor current before the transition was MCaa and the motor operated for one second, one second is added to the operating time OTaa of the corresponding motor current MCaa in the operation history information 42b. Then, the process returns to step ST4.

[0052] In step ST9, the ECU 4 determines whether the brush motor 22 has been stopped. For example, the brush motor 22 is stopped at the end of the vehicle height raising operation. If the ECU 4 determines that the brush motor 22 has been stopped, the process proceeds to step ST10. On the other hand, if the ECU 4 determines that the brush motor 22 has not been stopped, the process returns to step ST4.

[0053] In step ST10, the ECU 4 accumulates the operating time at the motor current before the motor 22 was stopped. That is, the operating time measured in step ST4 is added to the operating time of the corresponding motor current in the operation history information 42b. For example, if the brush motor 22 operated for two seconds at the motor current MCcb before the brush motor 22 was stopped, two seconds are added to the operating time OTcb of the corresponding motor current MCcb in the operation history information 42b. Then, the process returns.

[0054] [Life judgment operation] Next, the operation of determining the life of the brush motor 22 by the ECU 4 will be described with reference to FIG.

[0055] First, in step ST11 of FIG. 6, the ECU 4 determines whether a predetermined period has elapsed. This predetermined period is a preset period, for example, one day. If the ECU 4 determines that the predetermined period has elapsed, the process proceeds to step ST12. On the other hand, if the ECU 4 determines that the predetermined period has not elapsed, step ST11 is repeatedly performed. That is, the process waits until the predetermined period has elapsed. That is, steps ST12 and ST13, which will be described later, are performed at predetermined intervals.

[0056] Next, in step ST12, the product of current squared over time is calculated using the operation history information 42b by the ECU 4. The product of current squared over time is calculated using the above-mentioned formula (1).

[0057] Next, in step ST13, the ECU 4 determines whether the current squared time product exceeds a threshold value. If the ECU 4 determines that the current squared time product exceeds the threshold value, the process proceeds to step ST14. On the other hand, if the ECU 4 determines that the current squared time product does not exceed the threshold value, the process returns to step ST11.

[0058] In step ST14, the ECU 4 determines that the life of the brush motor 22 has expired. In this case, the ECU 4 uses a notification device (not shown) to notify the user that the life of the brush motor 22 has expired. This makes it possible to prompt the user to replace the brush motor 22 that has expired.

[0059] -effect- In this embodiment, as described above, the motor current is estimated based on the oil temperature and oil pressure, the operating time at the estimated motor current is measured, and the lifespan of the brush motor 22 is determined based on the motor current and operating time. Estimating the motor current based on the oil temperature and oil pressure in this manner makes it possible to determine the lifespan of the brush motor 22 without providing a current sensor for measuring the motor current. That is, estimating the motor current using the temperature sensor 34 and pressure sensor 35 already present in the vehicle height adjustment system 100 eliminates the need for an additional current sensor, thereby minimizing an increase in the number of components. Furthermore, determining the lifespan of the brush motor 22 allows the brush motor 22 to be used appropriately.

[0060] Furthermore, in this embodiment, the motor current is estimated using the map 42a, so that the motor current can be estimated appropriately.

[0061] Furthermore, in this embodiment, the end of the life is determined based on the current squared hours product, so that the end of the life can be appropriately determined.

[0062] -Other embodiments- It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention should not be interpreted solely by the above-described embodiments, but should be defined by the claims. The technical scope of the present invention also includes all modifications within the scope and meaning equivalent to the claims.

[0063] For example, in the above embodiment, an example is shown in which the hydraulic cylinder 1 is provided, but the present invention is not limited to this, and an air cylinder may be provided instead of the hydraulic cylinder.

[0064] In the above embodiment, an example has been shown in which the lifespan determination operation (see FIG. 6) is executed by the ECU 4. However, the present invention is not limited to this, and the ECU may transmit operation history information to a server device (not shown), so that the lifespan determination operation is executed by the server device.

[0065] In the above embodiment, the oil temperature parameter in the map 42a is set to three levels, and the oil pressure parameter in the map 42a is set to four levels. However, the map may have any number of levels for the oil temperature parameter, or any number of levels for the oil pressure parameter. That is, although the example in which twelve patterns of motor current are estimated is shown, the number of patterns of estimated motor current is not limited to this. [Industrial Applicability]

[0066] The present invention relates to a lifespan determining device for determining the lifespan of a brush motor which is a power source of a supply device for supplying a fluid. Judgment device Place Available. [Explanation of symbols]

[0067] 1FL Hydraulic cylinder (actuator) 1FR Hydraulic Cylinder (Actuator) 1RL Hydraulic cylinder (actuator) 1RR Hydraulic Cylinder (Actuator) 4 ECU (life determination device) 21 Oil pump (supply device) 22 Brush motor 42 Storage section 42a Map 42b Operation history information 100 Vehicle height adjustment system

Claims

1. A lifespan determination device for determining the lifespan of a brush motor that is a power source of a fluid supply device, comprising: a storage unit that stores a map for deriving a current using the temperature and pressure of the fluid as parameters; a current estimation unit that estimates a current of the brush motor using the map; an operation time measurement unit that measures an operation time of the brush motor at the current estimated by the current estimation unit; a lifespan determination unit that determines the lifespan of the brush motor; The current of the map is set to be smaller as the temperature of the map increases, and the current of the map is set to be larger as the pressure of the map increases, The storage unit stores operation history information, The operation history information includes an operation time of the brush motor at each current of the map, The lifespan determination unit calculates the product of current squared hours using the operating time at each current stored in the operation history information, and determines that the lifespan of the brush motor has arrived when the product of current squared hours exceeds a threshold value.

2. 2. The life determination device according to claim 1, The life determination device is characterized in that the supply device is configured to supply fluid to an actuator of a vehicle height adjustment system.

Images