Vehicle and vehicle control device

Abstract

The present invention provides a vehicle and a control device for the vehicle. When the temperature of the second power source of the vehicle is higher than a threshold value in the first mode in which three rotating elements of a differential device can be differentially driven and four-wheel drive is required, the vehicle is switched to the second mode in which the three rotating elements are integrated, and when the temperature of the second power source is higher than the threshold value in the first mode but four-wheel drive is not required, the output of the second power source is limited while maintaining the first mode.

Description

Technical Field

[0001] The present invention relates to a vehicle and a control device for the vehicle. Background Art

[0002] As a power transmission device mounted on a vehicle, a transfer case is known that distributes power from an engine (first power source) and transmits it to the front wheels and rear wheels. The output side of the transfer case is connected to a transmission shaft for the front wheels and a transmission shaft for the rear wheels. In addition, in the transfer case, it is possible to switch between a two-wheel drive state in which power is output to only one transmission shaft and a four-wheel drive state in which power is output to both transmission shafts.

[0003] International Publication No. 2010 / 141682 discloses that: in a transfer case having an auxiliary power source (second power source) in a transfer case housing, power output from the second power source is transmitted to the front and rear wheels via a differential device. In the structure described in International Publication No. 2010 / 141682, by fixing one of the three rotating elements included in the differential device to the transfer case housing, the differential device can function as a transmission, and the rotation of the first power source is changed in speed by the differential device and transmitted to the output member. Summary of the invention

[0004] In the structure described in International Publication No. 2010 / 141682, since the second power source is a motor, it is desirable to suppress the temperature rise of the motor. Therefore, when the temperature of the motor is high, it is considered to perform output control to suppress the output of the motor in order to reduce the temperature. However, if the output of the motor is suppressed in the four-wheel drive state, the driving force of the front wheel will be reduced, so it is possible that the four-wheel drive cannot be maintained.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle and a control device for the vehicle that can generate a required driving force at a driving wheel according to a running state.

[0006] The vehicle of the present invention is equipped with a power transmission device, which includes: a first input shaft, the first input shaft is input with power from a first power source; a second input shaft, the second input shaft is input with power from a second power source; a first output shaft, the first output shaft outputs power to a first drive wheel; a second output shaft, the second output shaft outputs power to a second drive wheel; a differential device, the differential device having a first rotating element connected to the second input shaft, a second rotating element connected to the second output shaft, and a third rotating element connected to the first output shaft as three rotating elements; and a coupling device, the coupling device selectively coupling any two of the three rotating elements, The power transmission device is capable of switching between a first mode in which the engagement device is released and the three rotating elements can be differentially driven, and a second mode in which the engagement device is engaged and the three rotating elements are mechanically integrated. The vehicle is characterized in that, when the temperature of the second power source is higher than a threshold value in the first mode and it is necessary to drive both the first drive wheel and the second drive wheel, the vehicle is switched from the first mode to the second mode, and when the temperature of the second power source is higher than a threshold value in the first mode but it is not necessary to drive both the first drive wheel and the second drive wheel, the output of the second power source is limited while maintaining the first mode.

[0007] According to this structure, when the temperature of the second power source is higher than the threshold value in the first mode, the vehicle can be controlled to switch to the second mode in the case where both the first drive wheel and the second drive wheel need to be driven and the case where both the first drive wheel and the second drive wheel do not need to be driven, and the output of the second power source can be limited while maintaining the first mode. Thus, the required driving force can be generated at the drive wheel according to the running state of the vehicle.

[0008] Furthermore, when the required driving force is greater than a predetermined value, it may be determined that both the first driving wheel and the second driving wheel need to be driven, and when the required driving force is less than the predetermined value, it may be determined that both the first driving wheel and the second driving wheel do not need to be driven.

[0009] According to this configuration, it is possible to generate a necessary driving force at the drive wheels according to the required driving force.

[0010] Alternatively, when the vehicle speed is lower than a predetermined vehicle speed, it may be determined that both the first drive wheel and the second drive wheel need to be driven, and when the vehicle speed is higher than the predetermined vehicle speed, it may be determined that both the first drive wheel and the second drive wheel do not need to be driven.

[0011] According to this configuration, a required driving force can be generated at the drive wheels according to the vehicle speed.

[0012] In addition, it may be that when the road surface gradient is greater than a predetermined value when traveling on an uphill road, it is determined that both the first drive wheel and the second drive wheel need to be driven, and when the road surface gradient is below the predetermined value, it is determined that both the first drive wheel and the second drive wheel do not need to be driven.

[0013] According to this configuration, it is possible to generate a necessary driving force at the drive wheels according to the road surface gradient when traveling on an uphill road.

[0014] Furthermore, when the first drive wheel slips, it may be determined that both the first drive wheel and the second drive wheel need to be driven, and when the first drive wheel does not slip, it may be determined that both the first drive wheel and the second drive wheel do not need to be driven.

[0015] According to this configuration, when slip of the first drive wheel occurs, a necessary driving force can be generated at the second drive wheel.

[0016] In addition, it may be that when the driver operates a switch for switching the operation mode to drive both the first drive wheel and the second drive wheel, it is determined that both the first drive wheel and the second drive wheel need to be driven, and when the switch is not operated, it is determined that both the first drive wheel and the second drive wheel do not need to be driven.

[0017] According to this configuration, a required driving force can be generated at the drive wheels depending on whether the switch for switching the operation mode is operated by the driver.

[0018] In addition, it may be that, when the temperature of the second power source is higher than a threshold value in the first mode, a warning is issued to the driver to urge the temperature of the second power source to be lowered, and after the warning is issued, when there is no tendency for the temperature of the second power source to decrease, it is determined whether it is necessary to drive both the first drive wheel and the second drive wheel.

[0019] According to this configuration, the driver can be warned in advance, and the frequency of mode transition can be reduced.

[0020] The vehicle control device of the present invention is a vehicle control device as follows, wherein the vehicle is equipped with a power transmission device, the power transmission device comprising: a first input shaft, the first input shaft being input with power from a first power source; a second input shaft, the second input shaft being input with power from a second power source; a first output shaft, the first output shaft outputting power to a first drive wheel; a second output shaft, the second output shaft outputting power to a second drive wheel; a differential device, the differential device having a first rotating element connected to the second input shaft, a second rotating element connected to the second output shaft, and a third rotating element connected to the first output shaft as three rotating elements; and a coupling device, the coupling device selectively coupling any two of the three rotating elements, the The force transmission device is capable of switching between a first mode in which the engagement device is released and the three rotating elements are capable of differential movement, and a second mode in which the engagement device is engaged and the three rotating elements are mechanically integrated. The control device is characterized in that it has a control unit that switches the state of the differential device from the first mode to the second mode when the temperature of the second power source is higher than a threshold value in the first mode and when it is necessary to drive both the first drive wheel and the second drive wheel. The control unit limits the output of the second power source while maintaining the first mode when it is not necessary to drive both the first drive wheel and the second drive wheel even though the temperature of the second power source is higher than a threshold value in the first mode.

[0021] According to this structure, when the temperature of the second power source is higher than the threshold value in the first mode, the vehicle can be controlled to switch to the second mode in the case where both the first drive wheel and the second drive wheel need to be driven and the case where both the first drive wheel and the second drive wheel do not need to be driven, and the output of the second power source can be limited while maintaining the first mode. Thus, the required driving force can be generated at the drive wheel according to the running state of the vehicle.

[0022] Furthermore, the control device may further include a determination unit that determines whether it is necessary to drive both the first drive wheel and the second drive wheel.

[0023] According to this configuration, it is possible to determine whether the vehicle is in a running state in which both the first drive wheel and the second drive wheel need to be driven.

[0024] Furthermore, the determination unit may determine that both the first drive wheel and the second drive wheel need to be driven when the required drive force is greater than a predetermined value, and determine that both the first drive wheel and the second drive wheel do not need to be driven when the required drive force is less than the predetermined value.

[0025] According to this configuration, a driving force corresponding to the required driving force can be generated at the driving wheels based on the determination result of the determination unit.

[0026] Furthermore, the determination unit may determine that both the first drive wheel and the second drive wheel need to be driven when the vehicle speed is lower than a predetermined vehicle speed, and determine that both the first drive wheel and the second drive wheel do not need to be driven when the vehicle speed is higher than the predetermined vehicle speed.

[0027] According to this configuration, a driving force corresponding to the vehicle speed can be generated at the drive wheels based on the determination result of the determination unit.

[0028] In addition, the determination unit may determine that it is necessary to drive both the first drive wheel and the second drive wheel when the road surface gradient is greater than a predetermined value when traveling on an uphill road, and determine that it is not necessary to drive both the first drive wheel and the second drive wheel when the road surface gradient is below a predetermined value.

[0029] According to this configuration, a driving force corresponding to the road surface gradient when traveling on an uphill road can be generated at the driving wheels based on the determination result of the determination unit.

[0030] Furthermore, the determination unit may determine that both the first drive wheel and the second drive wheel need to be driven when slippage of the first drive wheel occurs, and determine that both the first drive wheel and the second drive wheel do not need to be driven when slippage of the first drive wheel does not occur.

[0031] According to this configuration, when slip of the first drive wheel occurs, a necessary driving force can be generated at the second drive wheel.

[0032] In addition, the determination unit may determine that both the first drive wheel and the second drive wheel need to be driven when a switch for switching the operation mode to driving both the first drive wheel and the second drive wheel is operated by the driver, and determine that both the first drive wheel and the second drive wheel do not need to be driven when the switch is not operated.

[0033] According to this configuration, a required driving force can be generated at the drive wheels depending on whether the switch for switching the operation mode is operated by the driver.

[0034] Furthermore, the control unit may, when the temperature of the second power source in the first mode is higher than a threshold value, issue a warning to the driver to urge the driver to lower the temperature of the second power source, and the determination unit may, after issuing the warning, determine whether it is necessary to drive both the first drive wheel and the second drive wheel when there is no tendency for the temperature of the second power source to decrease.

[0035] According to this configuration, the driver can be warned in advance, and the frequency of mode transition can be reduced.

[0036] In the present invention, when the temperature of the second power source is higher than the threshold value in the first mode, the vehicle can be controlled to switch to the second mode and to limit the output of the second power source while maintaining the first mode, depending on whether the first drive wheel and the second drive wheel need to be driven or not. Thus, the required driving force can be generated at the drive wheels according to the running state of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0038] Figure 1 It is a schematic diagram schematically showing a vehicle according to an embodiment.

[0039] Figure 2 It is a schematic diagram schematically showing the structure of a transfer case in the embodiment.

[0040] Figure 3 This is a schematic diagram for explaining the transfer case in the lock mode.

[0041] Figure 4 1 is a flowchart showing control for selecting an operation mode of the vehicle.

[0042] Figure 5 : is a flowchart showing the control flow in the modification example. DETAILED DESCRIPTION

[0043] Hereinafter, a vehicle and a control device for the vehicle in an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

[0044] Figure 1 1 is a schematic diagram schematically showing a vehicle of an embodiment. The vehicle 1 includes an engine 2 as a power source, left and right front wheels 3L, 3R, left and right rear wheels 4L, 4R, and a power transmission device 10 that transmits the power of the engine 2 to the front wheels 3 and the rear wheels 4, respectively. The vehicle 1 is a four-wheel drive vehicle based on a front engine rear wheel drive. The rear wheel 4 is a main drive wheel that becomes a drive wheel in both two-wheel drive driving and four-wheel drive driving. On the other hand, the front wheel 3 is a secondary drive wheel that becomes a driven wheel in two-wheel drive driving and a drive wheel in four-wheel drive driving. In addition, in the present embodiment, the engine 2 is the "first power source", the rear wheel 4 is the "first drive wheel", and the front wheel 3 is the "second drive wheel".

[0045] The power transmission device 10 includes a transmission 11 connected to the engine 2, a transfer case 12 as a front and rear wheel power distribution device connected to the transmission 11, a front drive shaft 13 and a rear drive shaft 14 connected to the transfer case 12, a front wheel differential gear mechanism 15 connected to the front drive shaft 13, a rear wheel differential gear mechanism 16 connected to the rear drive shaft 14, left and right front wheel axles 17L and 17R connected to the front wheel differential gear mechanism 15, and left and right rear wheel axles 18L and 18R connected to the rear wheel differential gear mechanism 16. In addition, when the wheels and axles are not particularly distinguished between left and right, the reference numerals L and R are omitted and the wheels are described as the front wheel 3, the rear wheel 4, the front wheel axle 17, and the rear wheel axle 18.

[0046] The power output from the engine 2 is transmitted to the transfer case 12 via the transmission 11. The power transmitted to the transfer case 12 is transmitted from the transfer case 12 to the rear wheel 4 via the rear drive shaft 14, the rear wheel differential gear mechanism 16, and the power transmission path on the rear wheel side of the rear wheel axle 18 in sequence. In addition, a part of the power transmitted to the rear wheel 4 side is distributed to the front wheel 3 side by the transfer case 12, and is transmitted to the front wheel 3 via the front drive shaft 13, the front wheel differential gear mechanism 15, and the power transmission path on the front wheel side of the front wheel axle 17 in sequence.

[0047] In addition, the vehicle 1 includes an electronic control device 100 for controlling the vehicle 1. The electronic control device 100 is a control device for the vehicle 1. For example, the electronic control device 100 is configured to include a microcomputer including a CPU, a RAM, a ROM, an input / output interface, etc. The CPU performs various controls of the vehicle 1 by performing signal processing according to a program pre-stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 100 includes a determination unit 101 and a control unit 102.

[0048] Signals from various sensors mounted on the vehicle 1 are input to the electronic control device 100. For example, sensor signals from a control engine speed sensor, a motor rotation angle sensor, a vehicle speed sensor, an accelerator opening sensor, a 4WD selection switch for selecting a four-wheel drive state through a driver's operation, a slope sensor, a wheel speed sensor, etc. are input to the electronic control device 100. The electronic control device 100 performs drive control of the vehicle 1 based on the input sensor signals. For example, the determination unit 101 determines the driving state of the vehicle 1 based on the input signals from various sensors. And the control unit 102 controls the operation mode of the vehicle 1 based on the determination result of the determination unit 101. At this time, a command signal for controlling the engine 2, a command signal for controlling the transmission 11, a command signal for controlling the transfer case 12, etc. are output from the electronic control device 100.

[0049] Figure 2 1 is a schematic diagram schematically showing the structure of the transfer case in the embodiment. The transfer case 12 includes a transfer case housing 20 as a non-rotating member. The transfer case 12 includes a first input shaft 21, a second input shaft 22, a rear wheel side output shaft 23, a front wheel side output shaft 24, and a planetary gear device 25 in the transfer case housing 20. In addition, the transfer case 12 includes a transmission part 26 that functions as an input part on the front wheel side, a drive gear 27 that outputs power to the front wheel side output shaft 24, a driven gear 28 that is integrally provided with the front wheel side output shaft 24, and a front wheel drive chain 29 that connects the drive gear 27 and the driven gear 28, as a rotating member that forms a power transmission path on the front wheel side. In addition, the transfer case 12 includes a motor 30 that functions as a second power source and a coupling device 40 that switches the connection state of the rotating member in the transfer case housing 20. In the present embodiment, the rear wheel output shaft 23 is a “first output shaft”, the front wheel output shaft 24 is a “second output shaft”, the planetary gear device 25 is a “differential device”, and the motor 30 is a “second power source”.

[0050] The first input shaft 21 is an input member that inputs power from the engine 2 to the transfer case 12. The power from the engine 2 is transmitted to the first input shaft 21 via the transmission 11. For example, the first input shaft 21 is spline-fitted with an output member of the transmission 11.

[0051] The second input shaft 22 is an input member that inputs the power from the motor 30 to the planetary gear device 25. The power from the motor 30 is directly transmitted to the second input shaft 22. For example, the second input shaft 22 is spline-fitted with the output member (rotor shaft 33) of the motor 30, and rotates integrally with the rotor shaft 33.

[0052] The rear wheel side output shaft 23 is an output member for outputting power from the transfer case 12 to the rear wheels 4. The rear wheel side output shaft 23 is a main drive shaft that is arranged on the same axis as the first input shaft 21 and is connected to the rear propeller shaft 14.

[0053] The front wheel side output shaft 24 is an output member that outputs power from the transfer case 12 to the front wheels 3. The front wheel side output shaft 24 is a secondary drive shaft that is arranged on an axis different from the first input shaft 21 and the rear wheel side output shaft 23 and is connected to the front propeller shaft 13. The front wheel side output shaft 24 rotates by the rotation of the drive gear 27. The drive gear 27 is connected to the transmission unit 26 in a manner that rotates integrally.

[0054] The transmission part 26 is a rotating member that transmits power to the front wheel side output shaft 24. The drive gear 27 is connected to the transmission part 26 in a manner that rotates integrally. The drive gear 27 is a rotating member that functions as an output part on the front wheel side, and is an output gear that transmits power to the front wheel side output shaft 24. The transmission part 26 and the drive gear 27 are arranged in a manner that can rotate relative to the rear wheel side output shaft 23. In the transfer case 12, the drive gear 27, the transmission part 26, and the planetary gear device 25 are arranged in an axial direction on the same rotation center as the rear wheel side output shaft 23.

[0055] The planetary gear device 25 is a differential device having three rotation elements, and functions as a power distribution mechanism that distributes the power of the power source to the front wheels 3 and the rear wheels 4. The planetary gear device 25 is also a transmission unit that changes the speed of the rotation from the engine 2 and outputs it. Figure 2 The planetary gear device 25 shown as an example is a single pinion type planetary gear device. The planetary gear device 25 includes a sun gear S, a gear carrier C that supports a plurality of pinions so as to be able to rotate and revolve, and a ring gear R that meshes with the sun gear S via the pinions as three rotating elements. In the present embodiment, the sun gear S is the "first rotating element", the gear carrier C is the "second rotating element", and the ring gear R is the "third rotating element".

[0056] The second input shaft 22 and the first rotating member 51 are connected to the sun gear S in a manner of integral rotation. That is, the motor 30 is always connected to the sun gear S. The first rotating member 51 is a member that rotates integrally with the sun gear S, and has input gear teeth 51a. The first rotating member 51 is connected to the sun gear S via the second input shaft 22. In addition, a rotating member on the engine 2 side is selectively connected to the input gear teeth 51a through the engagement device 40.

[0057] The second rotating member 52 and the transmission unit 26 are connected to the carrier C so as to rotate integrally. The second rotating member 52 is a member that rotates integrally with the carrier C and has first output gear teeth 52a and second output gear teeth 52b. The carrier C selectively switches the connection object by the engagement device 40.

[0058] The third rotating member 53 is connected to the ring gear R so as to rotate integrally. The third rotating member 53 is a member that rotates integrally with the ring gear R, and has first output gear teeth 53 a and second output gear teeth 53 b. The ring gear R is selectively switched to be connected by the engagement device 40 .

[0059] The motor 30 is a rotating electrical machine (electric generator) that can function as an electric motor and a generator. The motor 30 is electrically connected to the battery via an inverter. The motor 30 is arranged on the same axis as the rear wheel side output shaft 23 inside the transfer case 20 and is configured to rotate integrally with the second input shaft 22. Figure 2 As shown, the motor 30 includes a rotor 31, a stator 32, and a rotor shaft 33. The rotor 31 is mounted on the rotor shaft 33 and rotates integrally with the rotor shaft 33. The stator 32 includes a stator core and a stator coil wound around the stator core. The second input shaft 22, the sun gear S, and the first rotating member 51 are connected to the rotor shaft 33 in a manner that they rotate integrally.

[0060] The coupling device 40 is a device for switching the connection state of the rotating components constituting the transfer case 12. The coupling device 40 functions as an input switching unit, a speed switching unit, and a distribution switching unit. The input switching unit switches between a direct connection state (first input state) in which the first input shaft 21 is directly connected to the rear wheel side output shaft 23, and a speed change state (second input state) in which the first input shaft 21 is connected to the sun gear S of the planetary gear device 25. Since the input switching unit is a high-low gear switching unit, it is included in the speed change switching unit. The speed change switching unit switches between a speed change state in which the rotation of the first input shaft 21 is changed in speed and transmitted to the rear wheel side output shaft 23, and a non-speed change state in which the rotation of the first input shaft 21 is transmitted to the rear wheel side output shaft 23 without changing speed. Furthermore, the distribution switching unit switches between a non-distribution state (two-wheel drive state) in which the power input from the first input shaft 21 is transmitted only to the rear wheel 4, and a distribution state (four-wheel drive state) in which the power input from the first input shaft 21 is distributed and transmitted to the front wheel 3 and the rear wheel 4. Figure 2 As shown, the engagement device 40 includes a first dog clutch 41 , a second dog clutch 42 , and a third dog clutch 43 .

[0061] The first dog clutch 41 is an engagement device that functions as an input switching unit and a speed switching unit. The first dog clutch 41 is a device that selectively switches the connection object of the first input shaft 21, and selectively connects the first input shaft 21 to the rear wheel side output shaft 23 or the sun gear S. That is, the first dog clutch 41 is a so-called high-low gear switching unit (speed switching unit), which switches between a direct connection state in which the rotation of the first input shaft 21 is transmitted to the rear wheel side output shaft 23 without changing the speed, and a speed change state in which the rotation of the first input shaft 21 is changed by the planetary gear device 25 and transmitted to the rear wheel side output shaft 23. That is, the first dog clutch 41 switches between a first input state (direct connection state) in which the power from the engine 2 is transmitted to the rear wheel side output shaft 23 without passing through the planetary gear device 25, and a second input state (speed change state) in which the power from the engine 2 is transmitted to the rear wheel side output shaft 23 via the planetary gear device 25.

[0062] In addition, the first dog clutch 41 has a first switching sleeve 44. The first switching sleeve 44 has first gear teeth 44a meshing with the gear teeth 21a of the first input shaft 21, and second gear teeth 44b meshing with the first gear teeth 23a of the rear wheel side output shaft 23 or the input gear teeth 51a of the first rotating member 51. The first switching sleeve 44 is moved in the axial direction by the actuator of the first dog clutch 41.

[0063] Furthermore, the first switching sleeve 44 is switched so that the meshing object of the second gear teeth 44b becomes either the rear wheel side output shaft 23 or the first rotating member 51 while the first gear teeth 44a are always meshed with the first input shaft 21. When the second gear teeth 44b are meshed with the first gear teeth 23a of the rear wheel side output shaft 23, the first dog clutch 41 is in the direct connection state (first input state). On the other hand, when the second gear teeth 44b are meshed with the input gear teeth 51a of the first rotating member 51, the first dog clutch 41 is in the speed change state (second input state).

[0064] The second dog clutch 42 is an engagement device that functions as a speed changeover section. The second dog clutch 42 is a device that selectively switches the connection object of the ring gear R, and selectively fixes the ring gear R to the fixed member 20a. That is, the second dog clutch 42 is a fixed switching section. The fixed member 20a is the transfer case 20 itself, or a non-rotating member integrated with the transfer case 20. In addition, the second dog clutch 42 switches between an engagement state (fixed state) in which the ring gear R is mechanically fixed, and a release state (non-fixed state) in which the ring gear R is released in a rotatable manner.

[0065] The second dog clutch 42 has a second switching sleeve 45. The second switching sleeve 45 has gear teeth 45a that mesh with the first output gear teeth 53a of the third rotating member 53 and the fixed member 20a. The second switching sleeve 45 is moved in the axial direction by the actuator of the second dog clutch 42.

[0066] Furthermore, the second switching sleeve 45 switches between a state of meshing with the third rotating member 53 and a state of not meshing with the gear teeth 45a in a state where the gear teeth 45a are always meshed with the fixed member 20a. That is, the second switching sleeve 45 switches between an engaged state (fixed state) in which the gear teeth 45a mesh with the first output gear teeth 53a of the third rotating member 53 and a released state (non-fixed state) in which the gear teeth 45a do not mesh with the first output gear teeth 53a of the third rotating member 53. That is, the second switching sleeve 45 switches between a fixed state in which the ring gear R is connected to the fixed member 20a and a non-fixed state in which the ring gear R is released in a rotatable manner.

[0067] The third dog clutch 43 is a coupling device that functions as a distribution switching unit and a speed switching unit. The third dog clutch 43 is a device that switches the connection relationship between the rear wheel side output shaft 23, the gear rack C and the ring gear R. Specifically, the third dog clutch 43, as a distribution switching unit, switches between a distribution state in which a part of the power transmitted to the rear wheel side output shaft 23 is distributed to the front wheel side output shaft 24, and a non-distribution state in which the power transmitted to the rear wheel side output shaft 23 is not distributed to the front wheel side output shaft 24. In addition, the third dog clutch 43, as a speed switching unit, switches between a differential state (power distribution mode) in which the planetary gear device 25 can perform differential movement and a non-differential state (locking mode) in which the differential movement of the planetary gear device 25 is limited. That is, the third dog clutch 43 is a coupling device that selectively connects two of the three rotating elements included in the planetary gear device 25. Furthermore, the third dog clutch 43 is switched to a power distribution mode in which the three rotating elements of the planetary gear device 25 are all able to rotate and differentially, and a locked mode in which the three rotating elements are locked so as not to rotate relative to each other. In this way, the third dog clutch 43 switches between a first non-distributed state (differential state) in which the rear wheel side output shaft 23 is not connected to the ring gear R and the gear carrier C, a second non-distributed state (integrated state) in which the ring gear R is connected only to the gear carrier C, a first distributed state (differential state) in which the rear wheel side output shaft 23 is connected only to the ring gear R, a second distributed state (integrated state) in which the rear wheel side output shaft 23 is connected to the ring gear R and the gear carrier C, and a third distributed state (differential state) in which the rear wheel side output shaft 23 is connected only to the gear carrier C.

[0068] In addition, the third dog clutch 43 has a third switching sleeve 46. The third switching sleeve 46 has a first gear tooth 46a and a second gear tooth 46b. The first gear tooth 46a and the second gear tooth 46b are meshed with the second output gear tooth 52b of the second rotating member 52, the second output gear tooth 53b of the third rotating member 53, and the second gear tooth 23b of the rear wheel side output shaft 23. The third switching sleeve 46 is moved in the axial direction by the actuator of the third dog clutch 43.

[0069] Furthermore, the third switching sleeve 46 switches between a first non-distributed state (differential state) in which the third rotating member 53 and the second rotating member 52 are meshed without being meshed with the rear wheel side output shaft 23, a second non-distributed state (integrated state) in which the third rotating member 53 and the second rotating member 52 are meshed without being meshed with the rear wheel side output shaft 23, a first distributed state (differential state) in which the third rotating member 53 and the rear wheel side output shaft 23 are meshed without being meshed with the second rotating member 52, a second distributed state (integrated state) in which the third rotating member 53 and the second rotating member 52 are meshed, and a third distributed state (differential state) in which the third rotating member 53 and the rear wheel side output shaft 23 are meshed without being meshed with the third rotating member 53. That is, the third switching sleeve 46 switches between a differential state (power distribution mode) in which the differential of the planetary gear device 25 is allowed and a non-differential state (mechanical lock mode) in which the differential of the planetary gear device 25 is restricted.

[0070] In this way, the transfer case 12 can be switched to a plurality of driving states by using the planetary gear device 25 and the coupling device 40. Therefore, when controlling the driving state of the transfer case 12, the electronic control device 100 controls the operation of the motor 30 and controls the state of the coupling device 40, thereby controlling the state of the planetary gear device 25. The command signal for controlling the transfer case 12 includes a command signal for controlling the motor 30 and a command signal for controlling the coupling device 40. The electronic control device 100 outputs a command signal to an actuator for operating the coupling device 40 to control the operation of the coupling device 40. Furthermore, the electronic control device 100 performs switching control of the coupling device 40, thereby being able to switch the state of the planetary gear device 25 between the first mode (power distribution mode), the second mode (locking mode) and the third mode (speed change mode).

[0071] The first mode is a state (differential state) in which the three rotating elements included in the planetary gear device 25 can be differentially driven. The first mode is a power distribution mode. Figure 2 As shown, the power distribution mode is a mode in which the sun gear S, the gear carrier C and the ring gear R can rotate relative to each other. That is, regardless of the state of the first dog clutch 41, the power distribution mode can be set by using the second dog clutch 42 and the third dog clutch 43. Therefore, the power distribution mode includes a state (differential state) in which the three rotating elements included in the planetary gear device 25 can be differentially connected to the motor 30, the rear wheel side output shaft 23, and the front wheel side output shaft 24 respectively. In addition, the power distribution mode is synonymous with the differential state.

[0072] The second mode is a state in which two of the three rotating elements included in the planetary gear device 25 are connected to each other (integrated state). The second mode is a locking mode. Figure 3As shown, the lock mode is a mode in which the three rotating elements of the planetary gear device 25 are locked by mechanical connection so as not to rotate relative to each other. The lock mode is synonymous with an integrated state and a non-differential state.

[0073] The third mode is a state in which any one of the three rotating elements included in the planetary gear device 25 is fixed to the fixed member 20a, and the remaining two rotating elements can rotate. The third mode is a speed change mode. The speed change mode is a mode in which the three rotating elements in the planetary gear device 25 function as an input element, an output element, and a reaction force element, respectively. The reaction force element is mechanically fixed.

[0074] Furthermore, in the vehicle 1, in the four-wheel drive state in which both the front wheel 3 and the rear wheel 4 are driven, the power of the power source is transmitted to the front wheel 3 and the rear wheel 4 via the planetary gear device 25. At this time, the planetary gear device 25 can be switched to a differential state (power distribution mode) and an integrated state (locking mode). That is, the transfer case 12 switches the state of the planetary gear device 25 by using the engagement device 40 in the four-wheel drive state, thereby being able to switch between a differential state in which the rotational differential between the rear drive shaft 14 and the front drive shaft 13 is not restricted and a non-differential state in which the rotational differential between them is restricted. That is, the transfer case 12 in the four-wheel drive state can be set to a first drive state (torque distribution 4WD mode) in which the rear wheel side output shaft 23 and the transmission unit 26 are in a state in which differential is possible, and a second drive state (fixed distribution 4WD mode) in which the rear wheel side output shaft 23 and the transmission unit 26 are in a non-differential state.

[0075] The first driving state is a four-wheel drive state in which power is transmitted to the front wheels 3 and the rear wheels 4, and the first dog clutch 41 is in the first input state, the second dog clutch 42 is in the release state, the third dog clutch 43 is in the first distribution state (differential state), and the planetary gear device 25 is in the power distribution mode (differential state). In this first driving state, the front and rear distribution control can be performed using the torque output from the motor 30. The first driving state is the so-called torque distribution 4WD mode. The purpose of the torque distribution mode is to generate a driving force on the front wheel 3 using the power (motor torque) output from the motor 30, so that the power distribution transmitted to the transmission unit 26 and the rear wheel side output shaft 23 changes.

[0076] Furthermore, when the transfer case 12 is in the first drive state, the planetary gear device 25 is in the power distribution mode, so the power transmitted from the engine 2 to the first input shaft 21 is transmitted to the rear wheel side output shaft 23, and the power transmitted from the motor 30 to the second input shaft 22 is transmitted to the front wheel side output shaft 24 via the planetary gear device 25. At this time, the distribution of the power transmitted to the front wheel side and the rear wheel side can be controlled by the power (motor torque) output from the motor 30. Therefore, in the torque distribution 4WD mode, the power distribution ratio of the front wheel 3 and the rear wheel 4 is determined by the operation of the motor 30. This power distribution ratio becomes the four-wheel drive performance.

[0077] The second drive state is a four-wheel drive state in which power is transmitted to the front wheels 3 and the rear wheels 4. The first dog clutch 41 is in the first input state, the second dog clutch 42 is in the release state, the third dog clutch 43 is in the second distribution state (integrated state), and the planetary gear device 25 is in the lock mode (integrated state). The second drive state is a so-called fixed distribution 4WD mode. The fixed distribution 4WD mode is a mode in which the power distribution transmitted to the rear wheel side output shaft 23 and the front wheel side output shaft 24 is mechanically fixed.

[0078] Furthermore, when the transfer case 12 is in the second drive state, the planetary gear device 25 is in the lock mode, so when the power of the engine 2 is distributed to the rear wheel side output shaft 23 and the front wheel side output shaft 24, the differential action of the planetary gear device 25 is limited by the third dog clutch 43, so that the three rotation elements have the same rotation speed. Therefore, in the fixed distribution 4WD mode, the power distribution ratio of the front wheel 3 and the rear wheel 4 is determined by mechanical connection. In other words, the power distribution ratio is fixed.

[0079] Thus, in the first driving state, the action (output torque) of the motor 30 is determined in order to determine the power distribution ratio. On the other hand, in the second driving state, the action (output torque) of the motor 30 can be determined independently of the power distribution ratio. Therefore, the electronic control device 100 can adjust the output of the motor 30 in a manner that does not affect the power distribution ratio when the transfer case 12 is in the second driving state.

[0080] Furthermore, in the first driving state, if the temperature of the motor 30 becomes high, the torque transmitted to the front wheel side output shaft 24 may be insufficient. That is, the driving force generated by the front wheel 3 may be insufficient. In this case, the 4WD performance is reduced due to the insufficient driving force of the front wheel 3, and the four-wheel drive state may not be maintained. Therefore, a countermeasure is required to deal with the temperature increase of the motor 30 in the first driving state.

[0081] Therefore, the electronic control device 100 is configured to control the transfer case 12 based on the temperature of the motor 30 so that the driving force of the drive wheels is not insufficient. When the motor 30 reaches a high temperature in the power distribution mode, the electronic control device 100 performs control to select the operation mode of the vehicle 1 according to the driving state of the vehicle 1.

[0082] When the operation mode of the vehicle 1 is selected, the determination unit 101 determines whether the motor temperature is high based on the signal from the temperature sensor that detects the temperature of the motor 30. When the determination unit 101 determines that the motor temperature is high, the control unit 102 implements control to switch the operation mode of the vehicle 1 to a desired state. For example, the control unit 102 can implement motor control to control the output of the motor 30 and engagement control to control the connection of the engagement device 40.

[0083] Figure 4 is a flowchart showing the control of selecting the operation mode of the vehicle. Figure 4 The control shown is repeatedly executed by the electronic control device 100 .

[0084] The electronic control device 100 determines whether the planetary gear device 25 is in the power distribution mode (step S1). In step S1, the determination unit 101 determines whether the planetary gear device 25 is in the differential state. That is, the determination unit 101 determines whether the third dog clutch 43 is in the first distribution state (differential state).

[0085] When the planetary gear device 25 is not in the power split mode (step S1 : NO), this control routine ends.

[0086] When the planetary gear device 25 is in the power distribution mode (step S1: Yes), the electronic control device 100 determines whether the temperature of the motor 30 is higher than the threshold value (step S2). In step S2, the determination unit 101 determines whether the motor temperature detected by the temperature sensor is higher than the threshold value. The threshold value is a preset value, for example, set to a temperature at which the performance of the motor 30 does not decrease. In addition, since the motor temperature does not rise when the motor 30 is not driven, in the determination process using the motor temperature in step S2, it is determined whether the motor 30 is driven.

[0087] When the temperature of the motor 30 is not higher than the threshold value (step S2 : NO), this control routine is terminated.

[0088] When the temperature of the motor 30 is higher than the threshold value (step S2: Yes), the electronic control device 100 determines whether the necessity of four-wheel drive (4WD) is high (step S3). In step S3, the determination unit 101 determines whether it is necessary to drive both the front wheels 3 and the rear wheels 4. At this time, the determination unit 101 can determine the necessity of four-wheel drive based on the required driving force, vehicle speed, the slope of the driving road, the selection state of the 4WD selection switch, etc.

[0089] For example, the electronic control device 100 detects the vehicle speed based on the signal from the vehicle speed sensor, and detects the accelerator opening based on the signal from the accelerator opening sensor. In addition, the electronic control device 100 calculates the required driving force based on the vehicle speed and the accelerator opening. In step S3, the determination unit 101 determines whether the calculated required driving force is greater than a predetermined value. And, if the required driving force is greater than the predetermined value, it is determined that four-wheel drive is required.

[0090] In step S3, the determination unit 101 determines whether the vehicle speed is lower than a predetermined speed. The low vehicle speed includes situations where four-wheel drive is required when driving on a rough road, towing, or driving uphill. Furthermore, when the vehicle speed is lower than the predetermined speed, it is determined that four-wheel drive is required.

[0091] In addition, the electronic control device 100 detects the rotation speed of the front wheel 3 (front wheel speed) and the rotation speed of the rear wheel 4 (rear wheel speed) based on the signal from the wheel speed sensor. And, the electronic control device 100 calculates the rotation speed difference obtained by subtracting the front wheel speed from the rear wheel speed. When the rotation speed difference is greater than a predetermined value, the determination unit 101 determines that the rear wheel 4 has slipped. Therefore, in step S3, the determination unit 101 determines whether the rear wheel 4 has slipped. When the rear wheel 4 has slipped, it is determined that four-wheel drive is required. The occurrence of wheel slip is not limited to the wheel speed sensor, and can also be detected based on input information from a camera (on-board camera) or a vibration sensor that photographs the wheel. The electronic control device 100 can determine whether it is a bad road based on the signal from the on-board camera and the vibration sensor, and can determine whether the slip frequency of each wheel is high based on the signal from the on-board camera. That is, the determination process of the driving state in step S3 can be performed based on multi-terrain select or the like.

[0092] In addition, the electronic control device 100 detects the slope of the driving road (road surface slope) based on the signal from the slope sensor. In step S3, the determination unit 101 determines whether the road surface slope (uphill slope) when driving on the uphill road is greater than a predetermined value based on the detected slope. And, if the road surface slope of the uphill road is greater than the predetermined value, it is determined that four-wheel drive is required.

[0093] In addition, the electronic control device 100 detects the selection operation of the 4WD selection switch by the driver. In step S3, the determination unit 101 determines whether the switching operation to the four-wheel drive state is accepted by the 4WD selection switch. And, in the case where the switch operation is a switching operation to the four-wheel drive, it is determined that the four-wheel drive is required. In other words, in the case where the 4WD mode (including off-road and bad weather modes) is selected in the selection status of the operating mode, it is determined that the necessity of the four-wheel drive is high.

[0094] Furthermore, when it is determined that the necessity of four-wheel drive is high (step S3: Yes), the electronic control device 100 changes the state of the planetary gear device 25 from the power distribution mode to the lock mode (step S4). In step S4, the third dog clutch 43 is switched from the first distribution state (differential state) to the second distribution state (integrated state) under the control of the control unit 102. As a result, the planetary gear device 25 changes from the power distribution mode (differential state) to the lock mode (integrated state). After the processing of step S4 is performed, the control routine ends.

[0095] On the other hand, when it is determined that the necessity of four-wheel drive is not high (step S3: No), the electronic control device 100 limits the output of the motor 30 (step S5). In step S5, the output of the motor 30 is limited while the power distribution mode is maintained under the control of the control unit 102. For example, when a positive determination is made in step S2, the motor torque after being limited in step S5 becomes smaller than the motor torque output by the motor 30. In this way, the operation (output torque) of the motor 30 is adjusted by the control unit 102. And, after the processing of step S5 is implemented, the control routine is terminated.

[0096] As described above, according to the embodiment, when the vehicle 1 is in a running state where four-wheel drive is required, the required driving force can be generated on both the front wheels 3 and the rear wheels 4. Thus, by making a decision to switch to the lock mode, the four-wheel drive performance can be maintained and the power source load can be adjusted (determination of whether to use the motor 30). Therefore, the output of the motor 30 can be reduced and the four-wheel drive state can be maintained.

[0097] As a modification of the above-described embodiment, when the operation mode of the vehicle 1 is automatically switched by the electronic control device 100, a warning may be given to the driver in advance. Figure 5 The control flow of this modified example is illustrated in FIG.

[0098] Figure 5 : is a flowchart showing the control flow in a modified example. Figure 5 Steps S11 to S12, S15 to S17 are shown in Figure 4Since steps S1 to S5 shown are similar processes, their description will be omitted.

[0099] like Figure 5 As shown, when the temperature of the motor 30 is higher than the threshold value (step S12: Yes), the electronic control device 100 issues a warning to the passengers of the vehicle 1 (step S13). In step S13, a warning is issued to the driver of the vehicle 1 to urge the transition of the operating state.

[0100] In step S13, a warning (information notification) is performed by displaying information on a display, outputting voice from a speaker, etc. For example, a message such as "Motor temperature rising" or "Please switch to lock mode" is displayed on a display included in the navigation device or outputted voice from a speaker.

[0101] Then, the electronic control device 100 determines whether the temperature of the motor 30 is decreasing (step S14). In step S14, based on the signal input from the temperature sensor, it is determined whether the temperature is decreasing compared to the motor temperature when the warning was issued in step S13. At this time, the determination unit 101 can determine whether the motor temperature is decreasing by comparing with the threshold used in step S12.

[0102] When the temperature of the motor 30 is on the downward trend (step S14 : Yes), this control routine is terminated.

[0103] On the other hand, if the temperature of the motor 30 is not decreasing (step S14: No), the control routine proceeds to step S15. Figure 4 The same processing is performed as in step S3 shown.

[0104] As described above, according to the modified example, it is possible to reduce the frequency of mode switching while suppressing a temperature increase of the motor 30 .

[0105] The engagement device included in the transfer case 12 only needs to have a function of switching the state of the planetary gear device 25 between at least the differential state (power distribution mode) and the integrated state (locking mode). That is, the structure of the engagement device 40 is not limited to the above-mentioned embodiment.

[0106] Furthermore, the transfer case 12 can be switched to a plurality of drive states in addition to the first drive state and the second drive state.

[0107] Furthermore, the vehicle 1 is not limited to a four-wheel drive vehicle based on a front engine rear wheel drive, but may also be a four-wheel drive vehicle based on a front engine front wheel drive. That is, as a modified example of the vehicle 1, the front wheel 3 may be a "first drive wheel", the rear wheel 4 may be a "second drive wheel", the front wheel side output shaft 24 may be a "first output shaft", and the rear wheel side output shaft 23 may be a "second output shaft".

[0108] In addition, the motor 30 is not limited to the structure arranged on the same axis as the first input shaft 21 and the rear wheel side output shaft 23, and can also be arranged on an axis different from the first input shaft 21 and the rear wheel side output shaft 23. Moreover, the power output from the motor 30 can also be transmitted to the second input shaft 22 via a reduction gear train formed by meshing multiple gears.

[0109] Furthermore, the motor 30 is constituted by a rotary electric machine (motor generator), and thus can generate electricity using the power from the engine 2. The electric power generated by the motor 30 is stored in the battery. Furthermore, the first power source is not limited to the engine, and may be a rotary electric machine.

Claims

1. A vehicle equipped with a power transmission device, the power transmission device comprising: a first input shaft to which power from a first power source is input; a second input shaft to which power from a second power source is input; a first output shaft, the first output shaft outputting power to the first driving wheel; a second output shaft, the second output shaft outputting power to a second driving wheel; a differential device having three rotation elements, namely, a first rotation element connected to the second input shaft, a second rotation element connected to the second output shaft, and a third rotation element connected to the first output shaft; and a joining device for selectively connecting any two of the three rotating elements; The power transmission device is switchable between a first mode in which the engagement device is released and the three rotation elements can be differentially driven, and a second mode in which the engagement device is engaged and the three rotation elements are mechanically integrated. The vehicle is characterized in that When the temperature of the second power source is higher than a threshold value in the first mode and both the first drive wheel and the second drive wheel need to be driven, the first mode is switched to the second mode; When the temperature of the second power source is higher than a threshold value in the first mode but it is not necessary to drive both the first drive wheel and the second drive wheel, the output of the second power source is limited while maintaining the first mode.

2. The vehicle according to claim 1, characterized in that When the required driving force is greater than a predetermined value, it is determined that both the first driving wheel and the second driving wheel need to be driven, When the requested driving force is equal to or less than a predetermined value, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

3. The vehicle according to claim 1 or 2, characterized in that: When the vehicle speed is lower than a predetermined vehicle speed, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the vehicle speed is equal to or higher than a predetermined vehicle speed, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

4. The vehicle according to claim 1 or 2, characterized in that: When the road surface gradient during traveling on an uphill road is greater than a predetermined value, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the road surface gradient is equal to or smaller than a predetermined value, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

5. The vehicle according to claim 1 or 2, characterized in that: When slip of the first drive wheel occurs, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the first drive wheel does not slip, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

6. The vehicle according to claim 1 or 2, characterized in that: When a switch for switching to an operation mode for driving both the first drive wheel and the second drive wheel is operated by a driver, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the switch is not operated, it is determined that both the first drive wheel and the second drive wheel do not need to be driven.

7. The vehicle according to claim 1 or 2, characterized in that: When the temperature of the second power source is higher than a threshold value in the first mode, a warning is given to the driver to urge the driver to lower the temperature of the second power source. After the warning is issued, if there is no tendency for the temperature of the second power source to decrease, it is determined whether it is necessary to drive both the first drive wheel and the second drive wheel.

8. A control device for a vehicle, the vehicle being equipped with a power transmission device, the power transmission device comprising: a first input shaft to which power from a first power source is input; a second input shaft to which power from a second power source is input; a first output shaft, the first output shaft outputting power to the first driving wheel; a second output shaft, the second output shaft outputting power to a second driving wheel; a differential device having three rotation elements, namely, a first rotation element connected to the second input shaft, a second rotation element connected to the second output shaft, and a third rotation element connected to the first output shaft; and a joining device for selectively connecting any two of the three rotating elements; The power transmission device is switchable between a first mode in which the engagement device is released and the three rotation elements can be differentially driven, and a second mode in which the engagement device is engaged and the three rotation elements are mechanically integrated. The control device is characterized in that a control unit configured to switch the state of the differential device from the first mode to the second mode when the temperature of the second power source is higher than a threshold value in the first mode and when both the first drive wheel and the second drive wheel need to be driven, The control unit limits the output of the second power source while maintaining the first mode when it is not necessary to drive both the first drive wheel and the second drive wheel even though the temperature of the second power source is higher than a threshold value in the first mode.

9. The vehicle control device according to claim 8, characterized in that: The control device further includes a determination unit that determines whether it is necessary to drive both the first drive wheel and the second drive wheel.

10. The vehicle control device according to claim 9, characterized in that: The determination unit, When the required driving force is greater than a predetermined value, it is determined that both the first driving wheel and the second driving wheel need to be driven, When the requested driving force is equal to or less than a predetermined value, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

11. The vehicle control device according to claim 9 or 10, characterized in that: The determination unit, When the vehicle speed is lower than a predetermined vehicle speed, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the vehicle speed is equal to or higher than a predetermined vehicle speed, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

12. The vehicle control device according to claim 9 or 10, characterized in that: The determination unit, When the road surface gradient during traveling on an uphill road is greater than a predetermined value, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the road surface gradient is equal to or smaller than a predetermined value, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

13. The vehicle control device according to claim 9 or 10, characterized in that: The determination unit, When slip of the first drive wheel occurs, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the first drive wheel does not slip, it is determined that it is not necessary to drive both the first drive wheel and the second drive wheel.

14. The vehicle control device according to claim 9 or 10, characterized in that: The determination unit, When a switch for switching to an operation mode for driving both the first drive wheel and the second drive wheel is operated by a driver, it is determined that both the first drive wheel and the second drive wheel need to be driven, When the switch is not operated, it is determined that both the first drive wheel and the second drive wheel do not need to be driven.

15. The vehicle control device according to claim 9 or 10, characterized in that: the control unit warns the driver to lower the temperature of the second power source when the temperature of the second power source is higher than a threshold value in the first mode; The determination unit determines whether it is necessary to drive both the first drive wheel and the second drive wheel when there is no tendency for the temperature of the second power source to decrease after the warning is issued.

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