Electric suspension system

Abstract

The present invention provides an electric suspension device that suppresses a sharp voltage rise caused by regenerative power from a motor in the electric suspension device. The electric suspension device (10) is mounted on a vehicle and includes an electric actuator (12) driven by a motor (46). The electric suspension device (10) includes: a voltage determination unit (211) that determines whether the electromotive force generated by the motor (46) is above a specified voltage (VA) when the motor (46) generates regenerative power; and an indicator unit (212) that short-circuits the motor (46) when the voltage determination unit (211) determines that the electromotive force generated by the motor (46) is above the specified voltage (VA).

Description

Technical Field

[0001] This invention relates to an electric suspension device. Background Technology

[0002] Previously, technologies related to motor-driven electric suspension systems mounted on vehicles were known.

[0003] For example, in the electric suspension device described in Patent Document 1, when the battery that supplies power to the motor is in a high-charge state, power is consumed from the battery to forcibly achieve a constant actuator force, i.e., a constant force, that causes the vehicle height to rise or fall, in order to eliminate the high-charge state of the battery.

[0004] Existing technical documents

[0005] Patent Document 1: International Patent Application Publication No. 2007-108316 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the electric suspension device described in Patent Document 1, a sharp voltage rise may occur when the motor generates regenerative power.

[0008] The purpose of this invention is to provide a vehicle control device that suppresses the sharp voltage rise caused by the regenerative power of the motor in the electric suspension device.

[0009] Methods for solving problems

[0010] One aspect of the present invention is an electric suspension device mounted on a vehicle, comprising an electric actuator driven by a motor, which short-circuits the motor when the driving voltage is above a predetermined voltage.

[0011] In other embodiments of the invention, the motor is short-circuited if the change in the driving voltage per unit time is greater than a predetermined change.

[0012] In another aspect of the invention, power supply to the motor is stopped when the motor is short-circuited.

[0013] In another embodiment of the invention, the electric actuator is disposed on each of the plurality of wheels. As the travel of the electric actuator disposed on the front wheel changes, when the driving voltage reaches or exceeds the predetermined voltage, the motor disposed on each of the plurality of wheels is kept short-circuited until the travel of the electric actuator disposed on the rear wheel ends.

[0014] Invention Effects

[0015] According to the present invention, it is possible to suppress the sharp voltage rise caused by the regenerative power of the motor in the electric suspension device. Attached Figure Description

[0016] Figure 1 This is a perspective view showing an example of the configuration of an electric suspension system.

[0017] Figure 2 This is a diagram illustrating an example of the structure of an electric suspension system.

[0018] Figure 3A This is a diagram illustrating an example of the structure of an inverter.

[0019] Figure 3B This is a diagram illustrating an example of the structure of a short-circuit circuit.

[0020] Figure 4 This is a flowchart illustrating an example of the processing controlled by the ECU.

[0021] Figure 5 This is a flowchart illustrating an example of the processing controlled by the ECU.

[0022] Label Explanation

[0023] 1: Vehicle; 10: Electric suspension system; 12: Electric actuator; 12A: First electric actuator; 12B: Second electric actuator; 12C: Third electric actuator; 12D: Fourth electric actuator; 13: Power line; 14: Signal line; 20: Electric suspension control ECU; 21A: Memory; 21B: Processor; 211: Voltage determination unit; 212: Indicator; 22: Inverter; 22U1, 22U2, 22V1, 22V2, 22W1, 22W2: MOSFETs; 26: Short circuit circuit; 30: Connector; 32: Inner tube; 34: Nut; 40: Outer tube; 42 : Threaded shaft; 44: Bearing; 46: Motor; 50u; 50v; 50w: Motor coil; 60a, 60b, 60c: Relay switch; 62a, 62b, 62c: Resistor; 64u, 64v, 64w: Power line; BD: Vehicle body; HB: Wheelbase; S1: Acceleration sensor; S2: Travel sensor; S3: Rotation angle sensor; S4: Voltage sensor; ST: Travel; T1: First time; TR: Wheel; V: Drive voltage; VA: Specified voltage; VD: Travel speed; α: Acceleration; θ: Rotation angle; ΔT: Time; ΔV: Change; ΔVA: Specified change. Detailed Implementation

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] [1. Structure of the electric suspension system]

[0026] Figure 1 This is a perspective view showing an example of the configuration of the electric suspension device 10. Figure 2 This is a diagram showing an example of the structure of the electric suspension device 10.

[0027] Reference Figure 1 and Figure 2 The electric suspension device 10 will be described.

[0028] like Figure 1 As shown, vehicle 1 has a body BD, four wheels TR, and an electric suspension system 10. The electric suspension system 10 includes an electric actuator 12 and an electric suspension control ECU 20.

[0029] The electric actuator 12 comprises a first electric actuator 12A, a second electric actuator 12B, a third electric actuator 12C, and a fourth electric actuator 12D. The first electric actuator 12A is positioned between the vehicle body BD and the right front wheel. The second electric actuator 12B is positioned between the vehicle body BD and the left front wheel. The third electric actuator 12C is positioned between the vehicle body BD and the right rear wheel. The fourth electric actuator 12D is positioned between the vehicle body BD and the left rear wheel.

[0030] The electric suspension control ECU (Electronic Control Unit) 20 controls each of the first electric actuators 12A to the fourth electric actuators 12D. The electric suspension control ECU 20 is connected to the first electric actuators 12A to the fourth electric actuators 12D respectively via power line 13 and signal line 14.

[0031] Power line 13 will come from Figure 2 The battery 16 shown supplies power to the first electric actuator 12A through the fourth electric actuator 12D. Additionally, power line 13 supplies regenerative power generated by each of the first electric actuator 12A through the fourth electric actuator 12D to... Figure 2 Battery 16 is shown. Signal line 14 will... Figure 2 The detection signals from sensors S1 to S4 are transmitted to the electric suspension control ECU 20.

[0032] Reference Figure 2 The following describes sensors S1 to S4.

[0033] In the following description, for convenience, the electric suspension control ECU 20 will sometimes be referred to as control ECU 20.

[0034] The first electric actuator 12A to the fourth electric actuator 12D have approximately the same structure. Therefore, in the following text, without distinguishing between the first electric actuator 12A to the fourth electric actuator 12D, the first electric actuator 12A to the fourth electric actuator 12D are sometimes simply referred to as electric actuator 12.

[0035] Next, refer to Figure 2 The structure of the electric actuator 12 will be described.

[0036] like Figure 2 As shown, the electric actuator 12 includes a connecting part 30, an inner tube 32, and a nut 34 as components on the wheel TR side. Additionally, the electric actuator 12 includes an outer tube 40, a threaded shaft 42, a bearing 44, and a motor 46 as components on the vehicle body BD side. The outer tube 40, bearing 44, and motor 46 are fixed to a chassis 48 located at the lower part of the vehicle body BD.

[0037] Reference Figure 3A The structure of motor 46 will be described.

[0038] The threaded shaft 42 is supported by a bearing 44 and a nut 34. The inner surface of the nut 34 engages with a threaded groove formed on the outer surface of the threaded shaft 42 via the bearing.

[0039] Motor 46 rotates threaded shaft 42, thereby moving nut 34 vertically. Moving nut 34 downward causes inner tube 32 to move downward. Moving nut 34 upward causes inner tube 32 to move upward.

[0040] In this way, the position of the inner tube 32 relative to the outer tube 40 fixed to the chassis 48 of the vehicle body BD in the vertical direction can be adjusted.

[0041] The connecting part 30 is connected to the wheel TR via a steering knuckle (not shown) fixed to the suspension device. When vibration is input to the connecting part 30 from the wheel TR side, and an upward acceleration α is applied to the connecting part 30, the inner tube 32 and nut 34 rise together with the outer tube 40. In this case, in the direction of absorbing the upward acceleration α, i.e., in the manner of the inner tube 32 moving upward, the motor 46 rotates the threaded shaft 42, thereby attenuating the vibration from the wheel TR to the vehicle body CD.

[0042] The electric actuator 12 is equipped with an acceleration sensor S1, a stroke sensor S2, and a rotation angle sensor S3.

[0043] Acceleration sensor S1 is fixed to the outer circumferential surface of inner tube 32, for example, to detect the acceleration α applied to the connecting part 30 from the wheel TR side. Acceleration sensor S1 is used for acceleration detection on the BD side of the vehicle body, and can also be configured to be mounted near chassis 48 or motor 46.

[0044] The stroke sensor S2 is positioned on the inner tube 32 opposite to the threaded shaft 42, and detects the stroke ST, which represents the downward movement of the nut 34. The stroke sensor S2 is composed of a distance sensor, etc.

[0045] The rotation angle sensor S3 is composed of a so-called rotary transformer, etc., and detects the rotation angle θ of the motor 46.

[0046] Voltage sensor S4 is a sensor that detects the drive voltage V applied to motor 46. It only needs to be able to detect the power supply voltage state of battery 16 and the regeneration voltage state of motor 46 during regeneration. For example, ... Figure 3A As shown, voltage sensor S4 detects the voltage between the terminals of battery 16 as the drive voltage V. When motor 46 is driven by electricity from battery 16, drive voltage V represents the power supply voltage of battery 16. When motor 46 generates regenerative power, drive voltage V represents the electromotive force of motor 46.

[0047] Acceleration α, stroke ST, rotation angle θ, and drive voltage V are output to the control ECU 20.

[0048] [2. Structure of the Electric Suspension Control ECU]

[0049] The control ECU 20 controls the motor 46 via the inverter 22 based on the detection results of the acceleration sensor S1, stroke sensor S2, rotation angle sensor S3 and voltage sensor S4.

[0050] Regarding the structure of inverter 22, refer to... Figure 3A Please provide an explanation.

[0051] The control ECU 20 has a memory 21A and a processor 21B.

[0052] Memory 21A is a storage device that non-volatilely stores programs and data executed by processor 21B. Memory 21A is composed of semiconductor storage elements such as magnetic storage devices, flash memory (ROM), or other types of non-volatile storage devices. Furthermore, memory 21A may also include RAM (Random Access Memory) that constitutes the working area of ​​processor 21B. Memory 21A stores data processed by control ECU 20 and control programs executed by processor 21B.

[0053] The processor 21B can be a single processor or a structure in which multiple processors function as the processor 21B. The processor 21B executes control programs to control the various parts of the electric suspension device 10.

[0054] The control ECU 20 includes a voltage determination unit 211 and an indication unit 212. Specifically, the processor 21B of the control ECU 20 functions as both the voltage determination unit 211 and the indication unit 212 by executing a control program.

[0055] The voltage determination unit 211 determines whether the driving voltage V is above the specified voltage VA.

[0056] Specifically, the voltage determination unit 211 determines whether the driving voltage V in any one of the first electric actuators 12A to the fourth electric actuator 12D is above a specified voltage VA. Furthermore, the specified voltage VA is greater than the power supply voltage of the battery 16.

[0057] The power supply voltage of battery 16 is, for example, 48V. The specified voltage VA is, for example, 54V.

[0058] Additionally, the voltage determination unit 211 can also determine whether the change in the driving voltage V per unit time ΔV is greater than or equal to a predetermined change ΔVA. The change ΔV represents the change in the driving voltage V per unit time (e.g., 5 msec).

[0059] Specifically, the voltage determination unit 211 can also determine whether, in any of the first electric actuators 12A to the fourth electric actuator 12D, when the motor 46 generates regenerative power, the change in electromotive force ΔV generated by the motor 46 per unit time is greater than or equal to a predetermined change ΔVA. Furthermore, the voltage determination unit 211 can also perform determinations based on a predetermined voltage VA and a predetermined change ΔVA.

[0060] Based on the determination result of the voltage determination unit 211, the indicator unit 212 short-circuits the motors 46 of each of the first electric actuators 12A to the fourth electric actuators 12D.

[0061] Specifically, when the voltage determination unit 211 determines that the drive voltage V of the electromotive force generated by the motor 46 is above the specified voltage VA, the indication unit 212 performs the following processing. That is, the indication unit 212 fixes the inverter 22 to be turned on via the drive circuit 24, thereby short-circuiting the motor 46 of each of the first electric actuator 12A to the fourth electric actuator 12D.

[0062] Furthermore, if the voltage determination unit 211 determines that the drive voltage V of the motor 46 that accompanies the stroke variation of at least one of the electric actuators 12 installed on the front wheel, namely the first electric actuator 12A and the second electric actuator 12B, is a predetermined voltage VA or higher, the indication unit 212 performs the following processing.

[0063] That is, the indicator 212 maintains the short circuit of the motors 46 of each of the first electric actuators 12A to the fourth electric actuator 12D until the stroke change of at least one of the electric actuators 12 installed on the rear wheels, namely the third electric actuator 12C and the fourth electric actuator 12D, ends. Furthermore, the stroke change of the electric actuator 12 installed on the rear wheels represents the stroke change corresponding to the stroke change of the electric actuator 12 installed on the front wheels.

[0064] The changes in travel include changes in travel ST that become longer, changes in travel ST that become shorter, changes in travel ST that become longer and then shorter, and changes in travel ST that become shorter and then longer.

[0065] When there is a step on the road surface where the vehicle 1 is traveling, which decreases in the direction of travel, the travel ST will change and the stroke will increase. For example, if the voltage determination unit 211 determines that the electromotive force of the motor 46 that accompanies the stroke change of the electric actuator 12 provided on the front wheel is above the specified voltage VA when the vehicle 1 passes over such a step, the indicator unit 212 maintains the short circuit of the motor 46 of each of the first electric actuator 12A to the fourth electric actuator 12D until the rear wheel passes over the step.

[0066] When there is a step on the road surface where vehicle 1 is traveling that rises in the direction of travel, the travel ST will decrease.

[0067] When there are depressions on the road surface where vehicle 1 is traveling, the travel ST will change from being longer to being shorter.

[0068] When there are protrusions on the road surface where vehicle 1 is traveling, the travel ST will change from short to long.

[0069] Furthermore, when the motors 46 of each of the first electric actuators 12A to the fourth electric actuators 12D are short-circuited, the indicator unit 212 stops supplying power to each of the first electric actuators 12A to the fourth electric actuators 12D.

[0070] Specifically, the indicator 212 stops supplying power to each of the first electric actuators 12A to the fourth electric actuator 12D by fixing the inverter 22 to disconnect.

[0071] Reference Figure 3A The drive circuit 24 and the inverter 22 will be described.

[0072] [3. Inverter Structure]

[0073] like Figure 2 As shown, the control ECU 20 controls the inverter 22 via the drive circuit 24. The control ECU 20 controls the rotation direction and speed of the motor 46 via the inverter 22.

[0074] Figure 3A This is a diagram showing an example of the structure of inverter 22.

[0075] like Figure 3A As shown, the inverter 22 includes MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors) 22U1, MOSFET 22U2, MOSFET 22V1, MOSFET 22V2, MOSFET 22W1, and MOSFET 22W2. These six MOSFETs are switched on and off according to instructions from the control ECU 20.

[0076] Motor 46, for example, is a 3-phase AC brushless motor, such as... Figure 3A As shown, it has three motor coils: 50u, 50v, and 50w.

[0077] The motor 46 drives the threaded shaft 42 to rotate by power supplied from the battery 16 via the inverter 22.

[0078] In addition, the motor 46 generates regenerative power based on the external force input from the wheel TR side to the threaded shaft 42, and outputs the generated power to the battery 16.

[0079] The indicator 212 of the control ECU 20 short-circuits the motor 46 by fixing the three MOSFETs on the low side of the inverter 22, namely MOSFET 22U2, MOSFET 22V2 and MOSFET 22W2, to the ON position.

[0080] In addition, the indicator 212 of the control ECU 20 stops supplying power from the battery 16 to the motor 46 by fixing the three MOSFETs on the high side of the inverter 22, namely MOSFET 22U1, MOSFET 22V1 and MOSFET 22W1, to the off.

[0081] [4. Structure of a short-circuit circuit]

[0082] In this embodiment, the case where the motor 46 is short-circuited by the inverter 22 is described, but it is not limited to this. Figure 3B As shown, the motor 46 can also be short-circuited by using the short-circuit circuit 26 of the relay switch.

[0083] like Figure 3BAs shown, short-circuit circuit 26 is configured between inverter 22 and motor 46. Short-circuit circuit 26 includes relay switches 60a, 60b, and 60c that are switched on and off according to instructions from control ECU 20, as well as resistors 62a, 62b, and 62c.

[0084] Relay switch 60a, according to the instruction from indicator 212, short-circuits the power lines 64u and 64v corresponding to motor coil 50u and motor coil 50v, respectively. Resistor 62a adjusts the current flowing in motor coil 50u and motor coil 50v when relay switch 60a short-circuits power lines 64u and 64v.

[0085] Relay switch 60b, according to the instruction from indicator 212, short-circuits the power lines 64V and 64W corresponding to motor coil 50V and motor coil 50W, respectively. Resistor 62b adjusts the current flowing in motor coil 50V and motor coil 50W when relay switch 60b short-circuits power lines 64V and 64W.

[0086] Relay switch 60c, according to the instruction from indicator 212, short-circuits the power lines 64u and 64w corresponding to motor coil 50u and motor coil 50w, respectively. Resistor 62c adjusts the current flowing in motor coil 50u and motor coil 50w when relay switch 60c short-circuits power lines 64u and 64w.

[0087] By using normally closed relay switches as relay switches 60a, 60b, and 60c, the motor 46 can be short-circuited without relying on the state of the power supply voltage V. For example, the motor 46 can also be short-circuited even when all the MOSFETs of the inverter 22 are turned off due to an abnormality in the power supply voltage V.

[0088] exist Figure 3B The diagram shows an example of short-circuit circuit 26 having three relay switches 60a to 60c. However, short-circuit circuit 26 can also be configured to have only relay switches 60a and 60b, which short-circuit the three phases of motor 46 through two relay switches 60a and 60b. Alternatively, short-circuit circuit 26 can also be a circuit structure in which resistors 62a to 62c are omitted depending on the characteristics of motor 46.

[0089] [5. Control ECU processing]

[0090] Figure 4This is a flowchart illustrating an example of the processing by the electric suspension control ECU 20. Figure 4 In this section, the voltage determination unit 211 will explain whether the driving voltage V of the electromotive force generated by the motor 46 of the electric actuator 12 installed on the front wheel is above the specified voltage VA.

[0091] like Figure 4 As shown, firstly, in step S101, the voltage determination unit 211 determines whether the driving voltage V associated with the electromotive force generated by the motor 46 of at least one of the electric actuators 12, i.e., the first electric actuator 12A and the second electric actuator 12B, provided on the front wheel, is a predetermined voltage VA or higher.

[0092] If the voltage determination unit 211 determines that the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 installed on the front wheel is not above the specified voltage VA (step S101: No), the process proceeds to standby mode. If the voltage determination unit 211 determines that the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 installed on the front wheel is above the specified voltage VA (step S101: Yes), the process proceeds to step S103.

[0093] Then, in step S103, the indicator unit 212 short-circuits the motors 46 of each of the first electric actuators 12A to the fourth electric actuator 12D. Specifically, the indicator unit 212 short-circuits the motors 46 of each of the first electric actuators 12A to the fourth electric actuator 12D by fixing the low side of the inverter 22 of each of the first electric actuators 12A to the fourth electric actuator 12D to be on. In addition, the indicator unit 212 stops supplying power from the battery 16 to the motors 46 by fixing the high side of the inverter 22 of each of the first electric actuators 12A to the fourth electric actuator 12D to be off.

[0094] Next, in step S105, the indicator unit 212 determines whether the stroke change of the electric actuator 12 installed on the rear wheel has ended. Specifically, the indicator unit 212 determines whether the stroke change of the electric actuator 12 installed on the rear wheel has ended, for example, based on the detection result of the stroke sensor S2.

[0095] If the indicator 212 determines that the stroke change of the electric actuator 12 installed on the rear wheel has ended (step S105: Yes), the process proceeds to step S109. If the indicator 212 determines that the stroke change of the electric actuator 12 installed on the rear wheel has not ended (step S105: No), the process proceeds to step S107.

[0096] Then, in step S107, the indicator unit 212 determines whether a first time T1 has elapsed since the voltage determination unit 211 determined that the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 provided on the front wheel is a predetermined voltage VA or higher. The first time T1 is calculated, for example, based on the wheelbase HB of the vehicle 1 and the driving speed VD of the vehicle 1 using the following formula (1).

[0097] T1=(HB / VD)+ΔT (1)

[0098] The time ΔT corresponds to the period during which the travel variation occurs.

[0099] If the instruction unit 212 determines that the first time T1 has not elapsed (step S107: No), the process returns to step S105. If the instruction unit 212 determines that the first time T1 has elapsed (step S107: Yes), the process proceeds to step S109.

[0100] Then, in step S109, the indicator unit 212 terminates the short circuit of the motors 46 of each of the first electric actuators 12A to the fourth electric actuator 12D. Additionally, the indicator unit 212 stops the power supply from the battery 16 to the motors 46 for the first electric actuators 12A to the fourth electric actuator 12D. Then, the process ends.

[0101] For reference Figure 4 As explained, when the voltage determination unit 211 determines that the drive voltage V associated with the stroke variation of the electric actuator 12 installed on the front wheel is above a predetermined voltage VA, the indicator unit 212 maintains the short circuit of the motor 46 of each of the first electric actuator 12A to the fourth electric actuator 12D until the stroke variation of the electric actuator 12 installed on the rear wheel ends. Therefore, it is possible to suppress the sharp rise in drive voltage V associated with the stroke variation of the electric actuator 12 installed on the rear wheel.

[0102] Figure 5 This is a flowchart illustrating an example of the processing by the electric suspension control ECU 20. Figure 5 In this section, the voltage determination unit 211 will explain whether the driving voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 installed on the rear wheel is a specified voltage VA or higher.

[0103] like Figure 5 As shown, firstly, in step S151, the voltage determination unit 211 determines whether the driving voltage V associated with the electromotive force generated by the motor 46 of at least one of the electric actuators 12 installed on the rear wheel, namely the third electric actuator 12C and the fourth electric actuator 12D, is above a predetermined voltage VA.

[0104] If the voltage determination unit 211 determines that the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 installed on the rear wheel is not above the specified voltage VA (step S151: No), the process enters a standby state. If the voltage determination unit 211 determines that the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 installed on the rear wheel is above the specified voltage VA (step S151: Yes), the process proceeds to step S153.

[0105] Then, in step S153, the indicator unit 212 short-circuits the motors 46 of each of the first electric actuators 12A to the fourth electric actuator 12D. Specifically, the indicator unit 212 short-circuits the motors 46 of each of the first electric actuators 12A to the fourth electric actuator 12D by fixing the low side of the inverter 22 of each of the first electric actuators 12A to the fourth electric actuator 12D to be on. In addition, the indicator unit 212 stops supplying power from the battery 16 to the motors 46 by fixing the high side of the inverter 22 of each of the first electric actuators 12A to the fourth electric actuator 12D to be off.

[0106] Next, in step S155, the indicator unit 212 determines whether the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 provided on the rear wheel is less than a specified voltage VA.

[0107] If the indicator 212 determines that the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 installed on the rear wheel is not less than the specified voltage VA (step S155: No), the process proceeds to standby mode. If the indicator 212 determines that the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 installed on the rear wheel is less than the specified voltage VA (step S155: Yes), the process proceeds to step S157.

[0108] Then, in step S157, the indicator unit 212 terminates the short circuit of the motors 46 of each of the first electric actuators 12A to the fourth electric actuator 12D. Additionally, the indicator unit 212 stops the power supply from the battery 16 to the motors 46 for the first electric actuators 12A to the fourth electric actuator 12D. Then, the process ends.

[0109] For reference Figure 5As explained, when the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 located on the rear wheel is above a predetermined voltage VA, the indicator 212 short-circuits the motor 46 of each of the first electric actuators 12A to the fourth electric actuator 12D. Furthermore, when the drive voltage V associated with the electromotive force generated by the motor 46 of the electric actuator 12 located on the rear wheel is less than the predetermined voltage VA, the indicator 212 terminates the short circuit of the motor 46 of each of the first electric actuators 12A to the fourth electric actuator 12D. Therefore, it is possible to suppress the rapid rise in drive voltage V associated with stroke variations of the electric actuator 12 located on the rear wheel.

[0110] Additionally, as referenced Figure 4 as well as Figure 5 As explained, when the motors 46 of each of the first electric actuators 12A to the fourth electric actuators 12D are short-circuited, the indicator unit 212 stops supplying power from the battery 16 to the motors 46 by fixing the high side of the inverter 22 of each of the first electric actuators 12A to the fourth electric actuators 12D to be disconnected. Therefore, it is possible to prevent overcurrent from flowing through the motors 46 of each of the first electric actuators 12A to the fourth electric actuators 12D.

[0111] [6. Structure and Effects]

[0112] As explained above, the electric suspension device 10 of this embodiment is an electric suspension device 10 mounted on a vehicle 1 and equipped with an electric actuator 12 driven by a motor 46. When the driving voltage V of the motor 46 is a predetermined voltage VA or higher, the motor 46 is short-circuited.

[0113] According to this structure, when the drive voltage V of motor 46 is above the specified voltage VA, motor 46 is short-circuited, thus suppressing the sharp rise in drive voltage V caused by the regenerative power of motor 46.

[0114] In addition, in the electric suspension device 10, when the change in the driving voltage V per unit time ΔV is greater than or equal to the specified change ΔVA, the motor 46 is short-circuited.

[0115] According to this structure, when the change in the driving voltage V per unit time ΔV is greater than or equal to a predetermined change ΔVA, the motor 46 is short-circuited. Therefore, the sharp rise in the driving voltage V caused by the regenerative power of the motor 46 can be suppressed.

[0116] In addition, in the electric suspension device 10, when the motor 46 is short-circuited, the power supply to the motor 46 is stopped.

[0117] According to this structure, when the motor 46 is short-circuited, the power supply to the motor 46 is stopped, thus preventing overcurrent from flowing through the motor 46.

[0118] In addition, the electric actuator 12 of the electric suspension device 10 is provided on each of the multiple wheels TR. When the drive voltage V reaches a specified voltage VA or above as the stroke of the electric actuator 12 provided on the front wheel changes, the motor 46 of each of the multiple wheels TR is kept short-circuited until the stroke change of the electric actuator 12 provided on the rear wheel ends.

[0119] According to this structure, when the electromotive force of the motor 46 associated with the stroke variation of the electric actuator 12 provided on the front wheel is above a predetermined voltage VA, the motor 46 of each of the plurality of wheels TR is kept short-circuited until the stroke variation of the electric actuator 12 provided on the rear wheel ends. Therefore, it is possible to suppress the sharp rise in drive voltage V caused by the regenerative power of the motor 46 associated with the stroke variation of the electric actuator 12 provided on the rear wheel.

[0120] [7. Other Implementation Methods]

[0121] Furthermore, the present invention is not limited to the structure of the above-described embodiments, and can be implemented in various ways without departing from its spirit.

[0122] For example, in the above embodiment, the electric suspension device 10 was described with the first electric actuator 12A to the fourth electric actuator 12D, but it is not limited to this. For example, the electric suspension device 10 may have the third electric actuator 12C and the fourth electric actuator 12D but not the first electric actuator 12A and the second electric actuator 12B. Conversely, the electric suspension device 10 may also have the first electric actuator 12A and the second electric actuator 12B but not the third electric actuator 12C and the fourth electric actuator 12D.

[0123] Furthermore, in the above embodiment, the description focuses on the case where the indicator unit 212 determines whether the stroke change of the electric actuator 12 installed on the rear wheel has ended based on the detection result of the stroke sensor S2, but it is not limited to this. For example, the indicator unit 212 may also determine whether the stroke change of the electric actuator 12 installed on the rear wheel has ended based on the detection result of the voltage sensor S4.

[0124] Furthermore, in the above embodiment, the case where the indicator 212 short-circuits the motor 46 by fixing the inverter 22 to the on, is described, but it is not limited to this. For example, the electric suspension device 10 may have a short-circuit circuit for short-circuiting the motor 46, and the indicator 212 may short-circuit the motor 46 via the short-circuit circuit.

[0125] Figure 2 At least some of the functional blocks shown can be implemented in hardware, or in a combination of hardware and software, and are not limited to a structure with independent hardware resources as shown in the figure.

[0126] The control program executed by the processor 21B of the electric suspension control ECU 20 of the electric suspension device 10 is stored in the memory 21A, but the control program can also be stored in an external HDD or the like.

[0127] To facilitate understanding of the processing of the electric suspension control ECU 20 in the electric suspension device 10, Figure 4 as well as Figure 5 The processing units in the flowcharts shown are divided according to the main processing content. The implementation method is not subject to change. Figure 4 as well as Figure 5 The processing units shown in the flowcharts are not limited by the method of segmentation or the naming of the processing units. The processing of the electric suspension control ECU 20 can be divided into more processing units based on the processing content, or it can be divided into a single processing unit containing more processing. The processing order of the above flowcharts is not limited to the examples shown.

[0128] The control method of the electric suspension control ECU 20 can be implemented by having the processor 21B of the electric suspension control ECU 20 execute a control program corresponding to the control method of the electric suspension control ECU 20. The control program can be recorded in a computer-readable recording medium. The recording medium can be a magnetic recording medium, an optical recording medium, or a semiconductor storage device. Specifically, examples include removable or fixed recording media such as floppy disks, CD-ROMs (Compact Disk Read Only Memory), DVDs (Digital Versatile Discs), Blu-ray discs, optical disks, flash memory, and card-type recording media. The recording medium can also be a non-volatile storage device such as RAM, ROM, or HDD, which is an internal storage device of the electric suspension device 10. The control program corresponding to the control method of the electric suspension control ECU 20 is stored in a server device or the like, and the control method of the electric suspension control ECU 20 can be implemented by downloading the control program from the server device to the electric suspension control ECU 20.

[0129] [8. Structure supported by the above embodiments]

[0130] The above implementation supports the following structures.

[0131] (Structure 1) An electric suspension device mounted on a vehicle, comprising an electric actuator driven by a motor, wherein the motor is short-circuited when the driving voltage of the motor is above a predetermined voltage.

[0132] According to the electric suspension device of structure 1, for example, when the motor generates regenerative power, and the electromotive force generated by the motor, i.e. the drive voltage, is above a specified voltage, the motor is short-circuited, thereby suppressing the sharp rise in drive voltage caused by the regenerative power of the motor.

[0133] (Structure 2) According to the electric suspension device of Structure 1, the motor is short-circuited when the change in the driving voltage per unit time is greater than or equal to a predetermined change.

[0134] According to the electric suspension device of structure 2, when the change in drive voltage exceeds a specified change, the motor is short-circuited, thus suppressing the sharp rise in drive voltage caused by the regenerative power of the motor.

[0135] (Structure 3) The electric suspension device according to Structure 1 or Structure 2, wherein, in the event of short-circuiting the motor, the supply of power to the motor is stopped.

[0136] According to the electric suspension device of structure 3, when the motor is short-circuited, the power supply to the motor is stopped, thus preventing overcurrent from flowing through the motor.

[0137] (Structure 4) The electric suspension device according to any one of Structures 1 to 3, wherein the electric actuator is provided on each of the plurality of wheels, and as the travel of the electric actuator provided on the front wheel changes, when the driving voltage reaches above the predetermined voltage, the motor provided on each of the plurality of wheels is kept short-circuited until the travel of the electric actuator provided on the rear wheel ends.

[0138] According to the electric suspension device of structure 4, as the stroke of the electric actuator installed on the front wheel changes, when the drive voltage reaches a predetermined voltage or higher, the motors of each of the multiple wheels are kept short-circuited until the stroke of the electric actuator installed on the rear wheel ends. Therefore, it is possible to suppress the sharp rise in drive voltage caused by the regenerative power of the motor that accompanies the stroke change of the electric actuator installed on the rear wheel.

Claims

1. An electric suspension device, which is mounted to a vehicle, has an electric actuator driven by a motor, wherein the motor is short-circuited in a case where a driving voltage of the motor is equal to or higher than a prescribed voltage, the electric actuator is provided to each of a plurality of wheels, in a case where the driving voltage reaches equal to or higher than the prescribed voltage in association with a stroke variation of the electric actuator provided to a front wheel, the short-circuit of the motor provided to each of the plurality of wheels is maintained until the stroke variation of the electric actuator provided to a rear wheel ends.

2. The electric suspension device according to claim 1, wherein the motor is short-circuited in a case where a variation amount per unit time of the driving voltage is equal to or higher than a prescribed variation amount.

3. The electric suspension device according to claim 1 or 2, wherein in a case where the motor is short-circuited, power supply to the motor is stopped.

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