Control device for parking lock

Abstract

To provide a control device for parking lock enabling parking lock while suppressing differential rotation.SOLUTION: A control device for parking lock includes a control section that controls a parking lock mechanism provided in an individual wheel independent driving transaxle. When a vehicle is in a stopped state, the control section causes torque of the transaxle of a target wheel for parking lock to be shared by and imposed on transaxles of wheels other than the target wheel. After the torque of the transaxle of the target wheel becomes zero, parking lock of the target wheel is performed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a parking lock control device.

Background Art

[0002] Patent Document 1 discloses a configuration in which a parking mechanism and a clutch mechanism are provided between a brake rotor and a drive motor.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration disclosed in Patent Document 1, for example, on a low-μ slope road or the like, when there is slip and differential rotation occurs while maintaining a vehicle speed of zero with a driving torque, there is a risk that the parking lock cannot be achieved.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a parking lock control device capable of performing a parking lock while suppressing differential rotation.

Means for Solving the Problems

[0006] The parking lock control device according to the present disclosure includes a control unit that controls a parking lock mechanism provided in a transaxle with independent wheel drive, and when the vehicle is stopped, the control unit shares and burdens the torque of the transaxle of the target wheel for which the parking lock is to be performed with the torque of the transaxles of the wheels other than the target wheel, and performs the parking lock of the target wheel after the torque of the transaxle of the target wheel becomes zero.

Effects of the Invention

[0007] According to the present disclosure, parking lock can be performed while suppressing differential rotation.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] The parking lock control device according to the embodiment of the present disclosure will be described with reference to the drawings. Note that the constituent elements in the following embodiments include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same.

[0010] (Parking Lock Control Device) The control device for the parking lock according to the embodiment will be described with reference to FIGS. 1 and 2. The control device for the parking lock according to the embodiment is for controlling the parking lock mechanisms provided in the transaxles with independent drive for each wheel.

[0011] The vehicle to which the control device for the parking lock according to the embodiment is applied is not particularly limited. The control device for the parking lock according to the embodiment may be mounted on, for example, a general engine vehicle (cab-over vehicle), a hybrid vehicle (HEV: Hybrid Electric Vehicle), a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle). Further, the control device for the parking lock according to the embodiment may be mounted on, for example, a fuel cell vehicle (FCEV: Fuel Cell Electric Vehicle), a battery electric vehicle (BEV: Battery Electric Vehicle).

[0012] A vehicle 1 to which the control device for the parking lock according to the embodiment is applied includes, for example, as shown in FIG. 1, a vehicle body 11, a plurality of wheels 12, a plurality of transaxles (TA) 13, and a control unit 14. In the figure, only the configurations necessary for realizing the control device for the parking lock according to the embodiment among the configurations of the vehicle 1 are excerpted and illustrated, and other configurations are omitted from the illustration.

[0013] The transaxle 13 is provided for each wheel 12. Further, a parking lock mechanism is provided in the transaxle 13.

[0014] The control unit 14 is an electronic control unit (ECU) having a microcomputer mainly composed of, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc.

[0015] Here, in the conventional parking lock control device, for example, when parking on a low-μ slope road and performing a parking lock, if a slip occurs and differential rotation occurs while maintaining a vehicle speed of zero with a driving torque, there is a risk that the parking lock cannot be performed.

[0016] Therefore, when the vehicle 1 stops, the control unit 14 shares and burdens the torque (driving torque) of the transfer axle 13 of the wheel 12 (hereinafter referred to as "target wheel" or "parking target wheel") for which the parking lock is to be performed with the torque of the transfer axle 13 of the wheels 12 other than the target wheel. Then, after the torque of the transfer axle 13 of the target wheel becomes zero, the control unit 14 performs a parking lock on the target wheel.

[0017] For example, as shown in FIG. 2, when the parking target wheels are "target wheels 1 and 2", the control unit 14 burdens the torque of the transfer axles 13 of the target wheels 1 and 2 with the torque of the transfer axles 13 of the wheels 12 other than the target wheels. Then, after the torque and the vehicle speed of the transfer axles 13 of the target wheels 1 and 2 become zero, the control unit 14 issues a parking lock-on parking command to the transfer axles 13 of the target wheels 1 and 2. In this way, by sharing the torque by wheels other than the parking target wheels, it is possible to perform a parking lock by setting the vehicle speed of the parking target wheels to zero while maintaining the stopped state.

[0018] Further, as will be described later, the control unit 14 may preferentially perform a parking lock on the transfer axle 13 of the wheel 12 on the mountain side with a small ground load on the boarding and alighting road, and then perform a parking lock on the transfer axle 13 of the wheel 12 on the valley side with a large ground load. This facilitates parking hold on the boarding and alighting road.

[0019] (Parking Lock Control Method 1) An example of the flow of the parking lock control method 1 executed by the parking lock control device according to the embodiment will be described with reference to FIG. 3.

[0020] First, the control unit 14 performs vehicle speed zero control to set the vehicle speed of the vehicle 1 to zero (step S1). Subsequently, the control unit 14 determines whether the vehicle speed of the vehicle 1 has become zero (step S2). Note that the determination in step S2 can be made using detection data from a vehicle speed sensor or the like mounted on the vehicle 1.

[0021] In step S2, when it is determined that the vehicle speed of the vehicle 1 has become zero (Yes in step S2), the control unit 14 reduces the torque of the parking target wheel and increases the torque of the wheels other than the parking target wheel (step S3). Subsequently, the control unit 14 determines whether the torque and vehicle speed of the parking target wheel have become zero (step S4).

[0022] In step S4, when it is determined that the torque and vehicle speed of the parking target wheel have become zero (Yes in step S4), the control unit 14 turns on the parking lock of the parking target wheel (step S5). Subsequently, the control unit 14 determines whether the parking lock of the parking target wheel has been completed (step S6). In step S6, when the parking lock of the parking target wheel has been completed (Yes in step S6), the control unit 14 completes this process.

[0023] In the above-mentioned step S2, when it is determined that the vehicle speed of the vehicle 1 has not become zero (No in step S2), the control unit 14 returns to the process of step S1. Also, in the above-mentioned step S4, when it is determined that the torque and vehicle speed of the parking target wheel have not become zero (No in step S4), the control unit 14 returns to the process of step S3. Further, in the above-mentioned step S6, when it is determined that the parking lock of the parking target wheel has not been completed (No in step S6), the control unit 14 returns to the process of step S5.

[0024] In the parking lock control device according to the embodiment described above, in the transaxle 13 with independent wheel drive having a parking lock mechanism, the torque of the transaxle 13 of the wheel 12 to be parked is shared by the transaxles 13 of the remaining wheels 12. Thereby, the torque of the transaxle 13 of the wheel 12 to be parked is made zero. By performing such control, it is possible to perform parking lock while suppressing differential rotation.

[0025] (Parking Lock Control Method 2) The parking lock control method 2 executed by the parking lock control device according to the embodiment will be described with reference to FIGS. 4 and 5.

[0026] For example, as shown in FIG. 4, consider the case where the angle in the front-rear direction (ramp) of the vehicle 1 is detected and the vehicle 1 is parked on the ramp. In this case, the control unit 14 preferentially parks the transaxle 13 of the wheel 12 on the uphill side with a small ground load. Then, the control unit 14 parks the transaxle 13 of the wheel 12 on the downhill side with a large ground load.

[0027] For example, in the case of an uphill road as shown in FIG. 4, the "wheel 12 on the uphill side with a small ground load" refers to the front wheels, and the "wheel 12 on the downhill side with a large ground load" refers to the rear wheels. On the other hand, in the case of a downhill road opposite to the figure, the "wheel 12 on the uphill side with a small ground load" refers to the rear wheels, and the "wheel 12 on the downhill side with a large ground load" refers to the front wheels.

[0028] Also, for example, in the case of an uphill road as shown in FIG. 4, as shown in FIG. 5, the control unit 14 causes the torque of the front-wheel transaxle 13 (front wheels TA1, 2) to be borne by the torque of the rear-wheel transaxle 13 (rear wheels TA1, 2). Then, after the torque and vehicle speed of the front-wheel transaxle 13 become zero, the control unit 14 issues a parking lock command for parking lock to the front-wheel transaxle 13. In this way, by sharing the torque with the wheel 12 on the valley side with a large ground load, the parking state can be easily maintained.

[0029] An example of the flow of the parking lock control method 2 executed by the parking lock control device according to the embodiment will be described.

[0030] First, the control unit 14 performs vehicle speed zero control to make the vehicle speed of the vehicle 1 zero (step S11). Subsequently, the control unit 14 determines whether the vehicle speed of the vehicle 1 has become zero (step S12). Note that the determination in step S12 can be made using detection data from a vehicle speed sensor or the like mounted on the vehicle 1.

[0031] In step S12, if it is determined that the vehicle speed of the vehicle 1 has become zero (Yes in step S12), the control unit 14 determines whether it is an uphill road (step S13). In step S13, if it is determined that it is an uphill road (Yes in step S13), the control unit 14 reduces the torque of the parking target wheel on the rear side and increases the torque of the wheels other than the parking target wheel (step S14). Subsequently, the control unit 14 determines whether the torque and vehicle speed of the parking target wheel have become zero (step S15).

[0032] In step S15, when it is determined that the torque and vehicle speed of the parking target wheel have become zero (Yes in step S15), the control unit 14 turns on the parking lock of the parking target wheel (step S16). Subsequently, the control unit 14 determines whether the parking lock of the parking target wheel has been completed (step S17). In step S17, when it is determined that the parking lock of the parking target wheel has been completed (Yes in step S17), the control unit 14 completes this process.

[0033] In the above-described step S13, when it is determined that it is not an uphill road (it is a downhill road) (No in step S13), the control unit 14 decreases the torque of the front-side parking target wheel and increases the torque of the wheels other than the parking target wheel (step S18). Subsequently, the control unit 14 determines whether the torque and vehicle speed of the parking target wheel have become zero (step S19).

[0034] In step S19, when it is determined that the torque and vehicle speed of the parking target wheel have become zero (Yes in step S19), the control unit 14 turns on the parking lock of the parking target wheel (step S20). Subsequently, the control unit 14 determines whether the parking lock of the parking target wheel has been completed (step S21). In step S21, when it is determined that the parking lock of the parking target wheel has been completed (Yes in step S21), the control unit 14 completes this process.

[0035] In the above-described step S12, when it is determined that the vehicle speed of the vehicle 1 has not become zero (No in step S12), the control unit 14 returns to the process of step S11. Also, in the above-described step S15, when it is determined that the torque and vehicle speed of the parking target wheel have not become zero (No in step S15), the control unit 14 returns to the process of step S14. Also, in the above-described step S17, when it is determined that the parking lock of the parking target wheel has not been completed (No in step S17), the control unit 14 returns to the process of step S16.

[0036] Also, in the above-described step S19, when it is determined that the torque and vehicle speed of the parking target wheel are not zero (No in step S19), the control unit 14 returns to the process of step S18. Also, in the above-described step S21, when it is determined that the parking lock of the parking target wheel is not completed (No in step S21), the control unit 14 returns to the process of step S20.

[0037] Further effects and modifications can be easily derived by those skilled in the art. Therefore, a broader aspect of the present invention is not limited to the specific details and representative embodiments represented and described as above. Accordingly, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Explanation of Signs

[0038] 1 Vehicle 11 Vehicle body 12 Wheels 13 Transaxle (TA) 14 Control unit

Claims

【Claim 1】 A control device for a parking lock mechanism provided in a transaxle with independent drive for each wheel, wherein the control unit when the vehicle is stopped, shares and burdens the torque of the transaxle of the target wheel for which parking lock is to be performed with the torque of the transaxles of the wheels other than the target wheel, and performs parking lock on the target wheel after the torque of the transaxle of the target wheel has become zero. A control device for parking lock.

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