JP6201772B2 - Control device for four-wheel drive vehicle and control method for four-wheel drive vehicle - Google Patents

Description

  The present invention is a four-wheel drive capable of switching between a four-wheel drive state in which the drive force of the drive source is transmitted to the main drive wheel and the auxiliary drive wheel and a two-wheel drive state in which the drive force of the drive source is transmitted only to the main drive wheel. The present invention relates to a vehicle control device and a control method.

  Conventionally, as a four-wheel drive vehicle capable of switching between a four-wheel drive state and a two-wheel drive state and a control device thereof, the one described in Patent Document 1 is known.

  In the four-wheel drive vehicle described in Patent Document 1, the driving force of the engine is transmitted only to the rear wheels in the two-wheel driving state, and the driving force of the engine is transmitted to the front wheels and the rear wheels in the four-wheel driving state. In the four-wheel drive state, the driving force of the engine is distributed to the rear propeller shaft and the front propeller shaft by transfer. The driving force distributed to the front propeller shaft is distributed to the right front drive shaft and the left front drive shaft by the front differential and transmitted to the left and right front wheels.

  Between the front differential and the right front drive shaft, an ADD (Automatic Disconnecting Differential) mechanism that functions as a disconnection / connection device is provided. A transfer clutch capable of interrupting transmission of driving force to the front propeller shaft is provided in the transfer. This transfer clutch is a hydraulic clutch capable of adjusting the torque transmitted to the front propeller shaft. The ADD mechanism can be switched between a locked state in which the right output portion of the front differential and the right front drive shaft are connected and a free state in which this connection is disconnected. The ADD mechanism and the transfer clutch are controlled by a control device.

  The control device cuts off the transmission of the driving force by the transfer clutch and the ADD mechanism during traveling in the two-wheel drive state to make the front propeller shaft non-rotating, and reduces the traveling resistance accompanying the rotation of the front propeller shaft. This running resistance includes rotational resistance due to oil scooping up in the front differential. Thus, fuel consumption performance is improved by reducing the running resistance during running in the two-wheel drive state.

  When switching from the two-wheel drive state to the four-wheel drive state, first, the torque required to start the rotation of the front propeller shaft is transmitted from the transfer clutch to the front propeller shaft, and the rotation of the front propeller shaft causes the ADD mechanism to The rotation of the input part (the right output part of the front differential) is synchronized with the rotation of the output part (the right front drive shaft) of the ADD mechanism. Then, after the rotation of the input / output unit of the ADD mechanism is synchronized, the ADD mechanism is switched from the free state to the locked state. Thereby, generation | occurrence | production of the shock at the time of making an ADD mechanism into a locked state is suppressed.

JP 2003-220847 A

  Lubricating oil (diff oil) used for lubrication of a differential device changes greatly in viscosity depending on the temperature, and increases in viscosity at low temperatures. For this reason, in order to synchronize the rotation of the connecting / disconnecting device such as the ADD mechanism, the propeller shaft must be rotated against the rotational resistance due to the viscosity of the lubricating oil. It may take a long time, and switching from the two-wheel drive state to the four-wheel drive state may not be performed quickly.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a control device for a four-wheel drive vehicle and a control method for a four-wheel drive vehicle that can reduce the time required for switching from a two-wheel drive state to a four-wheel drive state. And

  In order to solve the above problems, the present invention provides a four-wheel drive state in which the drive force of the drive source is transmitted to the main drive wheel and the auxiliary drive wheel, and two wheels that transmit the drive force of the drive source only to the main drive wheel. A control device for a four-wheel drive vehicle capable of switching between a drive state, wherein the four-wheel drive vehicle includes a propeller shaft that transmits drive force to the auxiliary drive wheel in the four-wheel drive state, and at least one meshing clutch. And disconnecting the propeller shaft from the main drive wheel and the auxiliary drive wheel in the two-wheel drive state, and the propeller shaft, the main drive wheel and the auxiliary drive wheel in the four-wheel drive state. A coupling mechanism capable of coupling the coupling mechanism, and transmitting a rotational force for synchronizing the meshing clutch to the propeller shaft when the coupling mechanism is disconnected. And when the meshing clutch is synchronized in the two-wheel drive state, when it is determined that the time required for the synchronization is equal to or greater than a first predetermined value, Provided is a control device for a four-wheel drive vehicle that rotates a propeller shaft.

  In order to solve the above problems, the present invention transmits a driving force of a driving source to a main driving wheel and an auxiliary driving wheel, and transmits a driving force of the driving source only to the main driving wheel. An apparatus for controlling a four-wheel drive vehicle capable of switching between a two-wheel drive state, wherein the four-wheel drive vehicle includes at least one propeller shaft that transmits driving force to the auxiliary drive wheel in the four-wheel drive state. Including two meshing clutches, which disconnects the connection between the propeller shaft and the main drive wheel and the auxiliary drive wheel in the two-wheel drive state, and the propeller shaft, the main drive wheel and the auxiliary in the four-wheel drive state. A coupling mechanism capable of coupling the drive wheels, and a rotational force for synchronizing the meshing clutch to the propeller shaft in a coupled and disconnected state of the coupling mechanism. And when the meshing clutch is synchronized in the two-wheel drive state, when it is determined that the time required for the synchronization exceeds a first predetermined value, the friction clutch A method of controlling a four-wheel drive vehicle that rotates the propeller shaft by operation is provided.

  According to the present invention, it is possible to shorten the time required for switching from the two-wheel drive state to the four-wheel drive state.

It is a block diagram which shows the schematic structure of the four-wheel drive vehicle by which the control apparatus which concerns on the 1st Embodiment of this invention is mounted. It is sectional drawing which shows the structural example of a torque coupling and a rear-wheel side gear mechanism. It is sectional drawing which shows the example of a schematic structure of a meshing clutch. It is sectional drawing which shows a driving force transmission apparatus and its peripheral part. The cam member is shown, (a) is a plan view of the cam member from the armature side, and (b) is a perspective view showing a part of the cam member. It is a perspective view which shows an armature. It is a perspective view which shows the some latching | locking part provided in the 2nd housing member. (A)-(d) is explanatory drawing which illustrates typically the operation | movement of a cam member and an armature with a latching | locking part. It is a flowchart which shows a part of process which the control part of a control apparatus performs. It is a graph which shows the example of the time change of the rotational speed difference of a front-and-rear wheel. It is a flowchart which shows a part of process which the control part of a control apparatus performs.

[Embodiment]
FIG. 1 is a configuration diagram showing a schematic configuration of a four-wheel drive vehicle equipped with a control device according to a first embodiment of the present invention.

(Configuration of four-wheel drive vehicle 200)
The four-wheel drive vehicle 200 includes an engine 202 as a drive source, a transmission 203, front wheels 204L and 204R as main drive wheels, rear wheels 205L and 205R as auxiliary drive wheels, and driving force of the engine 202 as front wheels 204L. , 204R and the rear wheels 205L, 205R, and a control device 9 for controlling the driving force transmission system 201. In FIG. 1, the letter “L” in the code indicates the left side with respect to the forward direction of the four-wheel drive vehicle 200, and the letter “R” indicates the right side with respect to the forward direction of the four-wheel drive vehicle 200. This four-wheel drive vehicle 200 has a four-wheel drive state in which the drive force of the engine 202 is transmitted to the front wheels 204L and 204R and the rear wheels 205L and 205R, and a two-wheel drive in which the drive force of the engine 202 is transmitted only to the front wheels 204L and 204R. The state can be switched.

  The driving force transmission system 201 includes a front wheel side driving force transmission system 201A, a rear wheel side driving force transmission system 201B, and a propeller shaft 20 that connects the front wheel side driving force transmission system 201A and the rear wheel side driving force transmission system 201B. doing. The propeller shaft 20 transmits driving force to the rear wheels 205L and 205R in the four-wheel drive state.

  A front wheel side gear mechanism 26 including a pinion gear 261 and a ring gear 262 that are meshed with each other is disposed at the end of the propeller shaft 20 on the front wheels 204L and 204R side. A rear wheel side gear mechanism 27 including a pinion gear 271 and a ring gear 272 that mesh with each other is disposed at the end of the propeller shaft 20 on the rear wheels 205L and 205R side.

  The front wheel side driving force transmission system 201A includes the front differential 21 and the meshing clutch 23, and is disposed on the front wheels 204L and 204R side of the propeller shaft 20. The front differential 21 includes side gears 211L and 211R, a pair of pinion gears 212, a gear support member 213 that rotatably supports the pair of pinion gears 212, and a front differential case 214 that houses the side gears 211L and 211R and the pair of pinion gears 212. Have. The front differential case 214 is connected to the transmission 203. The side gear 211L is connected to the axle shaft 24L on the front wheel 204L side, and the side gear 211R is connected to the axle shaft 24R on the front wheel 204R side.

  The meshing clutch 23 includes a first rotating member 231, a second rotating member 232, and a cylindrical sleeve 233 that connects the first rotating member 231 and the second rotating member 232 so as not to be relatively rotatable. The sleeve 233 can be moved back and forth in the direction by an actuator (not shown). When the sleeve 233 moves to one side in the axial direction, the first rotating member 231 and the second rotating member 232 are connected. When moving to the side, the connection between the first rotating member 231 and the second rotating member 232 is released. The first rotating member 231 is connected to the front differential case 214 and the second rotating member 232 is connected to the ring gear 262 so as not to rotate. Details of the configuration of the meshing clutch 23 will be described later.

  The rear wheel side driving force transmission system 201B includes a torque coupling 28 capable of continuously adjusting the transmission torque, the rear differential 22, and the driving force transmission device 1, and includes the propeller shaft 20 on the rear wheels 205L and 205R side. Is arranged. The torque coupling 28 is a multi-plate clutch capable of continuously adjusting the torque transmitted from the propeller shaft 20 to the rear differential 22 via the rear wheel side gear mechanism 27. The configuration of the torque coupling 28 will be described later.

  The rear differential 22 houses side gears 221L and 221R, a pair of pinion gears 222, a gear support member 223 that rotatably supports the pair of pinion gears 222, the side gears 221L and 221R, and the pair of pinion gears 222, and is integrated with the ring gear 272. A rotating rear differential case 224; The pair of pinion gears 222 mesh with the side gears 221L and 221R with their gear axes orthogonal to each other. The side gear 221L is connected to the axle shaft 29L on the rear wheel 205L side, and the side gear 221R is connected to the axle shaft 29R on the rear wheel 205R side via the driving force transmission device 1.

  The driving force transmission device 1 can connect and disconnect the side gear 221R of the rear differential 22 and the axle shaft 29R on the rear wheel 205R side. When the connection between the side gear 221R of the rear differential 22 and the axle shaft 29R on the rear wheel 205R side is cut off by the driving force transmission device 1, the driving force of the engine 202 is not transmitted to the rear wheel 205R, and the side gear of the rear differential 22 When 221L, 221R and the pair of pinion gears 222 are idle, the driving force is not transmitted to the rear wheel 205L, and a two-wheel driving state is achieved in which the driving force of the engine 202 is transmitted only to the front wheels 204L, 204R.

  On the other hand, when the driving force transmission device 1 connects the side gear 221R of the rear differential 22 and the axle shaft 29R on the rear wheel 205R side, the driving force can be transmitted from the rear differential case 224 to the rear wheel 205R, and the rear differential 22 can be transmitted. The driving force can be transmitted to the rear wheel 205L through the side gear 221L.

  The meshing clutch 23, the torque coupling 28, and the driving force transmission device 1 in the driving force transmission system 201 are controlled by the control device 9. The driving force transmission system 201 has three operation modes according to the operating states of the meshing clutch 23, the torque coupling 28, and the driving force transmission device 1. These three operation modes are switched by, for example, selection by a driver's switch operation.

  The first operation mode is an operation mode in which transmission of the driving force in each part of the meshing clutch 23, the torque coupling 28, and the driving force transmission device 1 is interrupted. In the first operation mode, a two-wheel drive state in which the driving force of the engine 202 is transmitted only to the front wheels 204L and 204R is set. Further, transmission of driving force from the front wheel side driving force transmission system 201A to the propeller shaft 20 is interrupted by the meshing clutch 23, and transmission of rotational force from the rear wheel side driving force transmission system 201B to the propeller shaft 20 is transmission of driving force. Since it is blocked by the device 1, the rotation of the propeller shaft 20 is stopped even when the four-wheel drive vehicle 200 is traveling. As a result, it is possible to reduce the running resistance resulting from the agitation resistance of the lubricating oil in the front wheel side gear mechanism 26 and the rear wheel side gear mechanism 27 and the rotation resistance of a bearing (not shown) that supports the rotation of the propeller shaft 20. .

  In the second operation mode, the meshing clutch 23 and the driving force transmission device 1 are always in a connected state (a state in which the driving force can be transmitted), and the driving force corresponding to the transmission torque of the torque coupling 28 is applied to the rear wheels 205L and 205R. This is an operation mode to be transmitted. The control device 9 determines the difference in rotational speed between the front and rear wheels (difference between the average rotational speed of the front wheels 204L and 204R and the average rotational speed of the rear wheels 205L and 205R) and the acceleration operation amount (depressed amount of the accelerator pedal) by the driver. Based on this, command transmission torque is calculated, and a current corresponding to the command transmission torque is supplied to the torque coupling 28. The torque coupling 28 transmits a driving force from the propeller shaft 20 to the pinion gear 271 with a transmission torque corresponding to the supplied current.

  The third operation mode is an operation mode in which the two-wheel drive state and the four-wheel drive state are automatically switched based on the rotational speed difference between the front and rear wheels, the acceleration operation amount, the vehicle speed, and the like. The clutch 23 and the driving force transmission device 1 are connected and disconnected (disconnected state), and the meshing clutch 23 and the driving force transmission device 1 are connected in the four-wheel drive state. In the two-wheel drive state, the rotation of the propeller shaft 20 is stopped. In the four-wheel drive state, similarly to the second operation mode, the control device 9 calculates a command transmission torque based on the rotational speed difference between the front and rear wheels, the acceleration operation amount, and the like, and a current corresponding to the command transmission torque. Is supplied to the torque coupling 28.

  In the third operation mode, when the meshing clutch 23 and the driving force transmission device 1 are changed from the connection cutoff state to the connection state, the rotational force of the right rear wheel 205R is increased via the driving force transmission device 1 and the torque coupling 28. After transmission to the propeller shaft 20 and rotation of the propeller shaft 20 to complete synchronization of the meshing clutch 23, the meshing clutch 23 is brought into a connected state. Here, the synchronization of the meshing clutch 23 means that the rotational speed of the input side rotating member (front differential case 214) and the rotational speed of the output side rotating member (ring gear 262 of the front wheel side gear mechanism 26) are substantially the same. It means becoming.

  The control device 9 includes a storage unit 91 including storage elements such as a ROM (Read Only Memory) and a RAM (Random Access Memory), a CPU (Central Processing Unit) that operates according to a program stored in the storage unit 91, and the like. Unit 92, and meshing clutch 23, torque coupling 28, and current output circuit 93 that outputs current to driving force transmission device 1 based on the calculation processing result of control unit 92.

(Configuration of torque coupling 28 and rear wheel side gear mechanism 27)
FIG. 2 is a cross-sectional view showing a configuration example of the torque coupling 28 and the rear wheel side gear mechanism 27. The torque coupling 28 is housed in the differential carrier 220 together with the rear differential 22 and the rear wheel side gear mechanism 27. The differential carrier 220 is filled with lubricating oil (differential oil) L.

  The torque coupling 28 includes a bottomed cylindrical front housing 281 rotatably supported by a differential carrier 220 via a bearing 220a, a rear housing 282 fixed to an end of the front housing 281 on the opening side, A main clutch 283 that couples the housing 281 and the pinion gear 271 so as to transmit torque is provided, and an electromagnetic clutch mechanism 284 and a cam mechanism 285 that generate a pressing force that presses the main clutch 283 in the axial direction.

  The front housing 281 is connected to the propeller shaft 20 via a mounting member 286. A spline engaging portion 281 a is formed on the inner peripheral surface of the front housing 281. One end of the pinion gear 271 is accommodated in the front housing 281, and a spline engaging portion 271 a is formed on the outer peripheral surface of the one end. The rear housing 282 is composed of an annular nonmagnetic body disposed in the central portion in the radial direction and outer and inner annular magnetic bodies sandwiching the nonmagnetic body.

  The main clutch 283 is a multi-plate clutch composed of a plurality of outer clutch plates 283a and a plurality of inner clutch plates 283b. The plurality of outer clutch plates 283a are spline-engaged with the spline engaging portions 281a of the front housing 281 to The inner clutch plate 283b is spline-engaged with the spline engaging portion 271a of the pinion gear 271. The main clutch 283 receives axial pressing force, and the plurality of outer clutch plates 283a and the plurality of inner clutch plates 283b frictionally slide to transmit torque.

  The electromagnetic clutch mechanism 284 includes an electromagnetic coil 284a, an annular armature 284b that moves in the axial direction by the electromagnetic force of the electromagnetic coil 284a, and a pilot clutch 284c that is pressed by the axial movement of the armature 284b. The cam mechanism 285 includes a first cam member 285a coupled to the pilot clutch 284c, a second cam member 285b rotatable relative to the first cam member 285b, and a space between the first cam member 285a and the second cam member 285b. And a rolling element 285c that can roll.

  When the electromagnetic coil 284a is energized, the armature 284b presses the pilot clutch 284c, and the rotational force of the front housing 281 is transmitted to the first cam member 285a via the pilot clutch 284c. As a result, the first cam member 285a rotates with respect to the second cam member 285b, and the second cam member 285b presses the main clutch 283 by a cam action.

  The pressing force applied to the main clutch 283 varies according to the electromagnetic force generated by the electromagnetic coil 284a. That is, the control device 9 can adjust the driving force transmitted from the propeller shaft 20 to the pinion gear 271 via the main clutch 283 by increasing or decreasing the current supplied to the electromagnetic coil 284a.

  The pinion gear 271 has a gear portion 271b that meshes with the ring gear 272 at the other end opposite to the one end where the spline engaging portion 271a is formed. The gear portion 271b and the ring gear 272 of the pinion gear 271 are made of a hypopipe gear, and the meshing thereof is lubricated by the lubricating oil L. Further, the pinion gear 271 has a shaft portion 271c closer to the torque coupling 28 than the gear portion 271b is rotatably supported by the differential carrier 220 by a pair of bearings 220b and 220c. The pair of bearings 220b and 220c are tapered roller bearings. The pair of bearings 220b and 220c are lubricated by the lubricating oil L.

  When the pinion gear 271 rotates, the ring gear 272 scoops up the lubricating oil L and stirs it, so that stirring resistance is generated. Also, rotational resistance is generated in the pair of bearings 220b and 220c. These stirring resistance and rotational resistance increase as the viscosity of the lubricating oil L increases.

(Configuration of meshing clutch 23)
FIG. 3 is a cross-sectional view illustrating a schematic configuration example of the meshing clutch 23. In FIG. 3, a portion above the rotation axis O ₁ of the meshing clutch 23 is shown.

  The first rotating member 231 has an annular shape through which the axle shaft 24R on the front wheel 204R side is inserted, and is fixed to an end portion of the front differential case 214. A plurality of spline teeth 231 a are formed on the outer periphery of the first rotating member 231.

  The second rotating member 232 has a cylindrical shape through which the axle shaft 24R on the front wheel 204R side is inserted, and is supported so as to be rotatable relative to the first rotating member 231 on the same axis. A plurality of spline teeth 232a are formed on the outer periphery of one end of the second rotating member 232 on the first rotating member 231 side. A ring gear 262 of the front wheel side gear mechanism 26 is fixed to the outer periphery at the other end of the second rotating member 232.

  The sleeve 233 has a cylindrical shape in which a plurality of spline teeth 233a are formed on the inner peripheral surface. The plurality of spline teeth 233a always mesh with the plurality of spline teeth 232a of the second rotating member 232. In addition, the plurality of spline teeth 233 a mesh with the plurality of spline teeth 231 a of the first rotating member 231 as the sleeve 233 moves in the axial direction toward the front differential case 214. An annular groove 233b is formed on the outer peripheral side of the sleeve 233, and a fork 234 is slidably fitted in the groove 233b. The fork 234 can move forward and backward together with the sleeve 233 by an unillustrated actuator controlled by the control device 9.

  When the spline teeth 233a of the sleeve 233 and the spline teeth 231a of the first rotating member 231 mesh with each other, the front differential case 214 and the propeller shaft 20 are connected so as not to be relatively rotatable. That is, the front wheels 204L and 204R and the propeller shaft 20 are connected in the four-wheel drive state. On the other hand, when the meshing between the spline teeth 233a of the sleeve 233 and the spline teeth 231a of the first rotating member 231 is released, the front wheels 204L and 204R and the propeller shaft 20 are disconnected from each other.

(Configuration of the driving force transmission device 1)
FIG. 4 is a cross-sectional view showing the driving force transmission device 1 and its peripheral part. The driving force transmission device 1 is housed in the housing 10 and transmits the driving force between the intermediate shaft 11 that is connected to the side gear 221R of the rear differential 22 so as not to rotate relative to the axle shaft 29R on the rear wheel 205R side.

  The housing 10 includes a first housing member 101 and a second housing member 102, and the first housing member 101 and the second housing member 102 are coupled by a bolt 103.

  The intermediate shaft 11 integrally includes a shaft portion 110 rotatably supported on the housing 10 by ball bearings 104 and a cylindrical portion 111 provided at an end portion of the shaft portion 110 opposite to the side gear 221R. Yes. The cylindrical portion 111 has a cylindrical shape with an accommodation space 11 a formed therein, and has an outer diameter larger than that of the shaft portion 110. The accommodation space 11a is open at the end opposite to the shaft 110.

  One end of a cylindrical inner shaft 12 is accommodated in the accommodating space 11a. The inner shaft 12 is spline-fitted with an axle shaft 29R inserted through the inner shaft 12 and rotates integrally with the axle shaft 29R. A ball bearing 112 is disposed between the outer peripheral surface of the inner shaft 12 and the inner peripheral surface of the accommodation space 11 a of the cylindrical portion 111. Further, a ball bearing 105 is disposed between the outer peripheral surface of the end portion of the inner shaft 12 opposite to the cylindrical portion 111 and the inner surface of the housing 10.

  A plurality of spline protrusions 12 a are formed on the outer peripheral surface of the inner shaft 12. Further, a cylindrical meshing member 13 is fitted on the inner shaft 12, and the spline projection 12 a is engaged with a spline projection 13 a formed on the inner peripheral surface of the meshing member 13. Thereby, the meshing member 13 is not rotatable relative to the inner shaft 12 and is movable in the axial direction.

  A plurality of axial holes 13c are formed in the meshing member 13, and one end of a return spring 131 is accommodated in the axial hole 13c. The other end of the return spring 131 is engaged with the spline protrusion 12 a of the inner shaft 12 and abuts on a receiving member 132 whose axial movement is restricted by the ball bearing 112. The return spring 131 is formed of a coil spring, for example, and biases the meshing member 13 in a direction away from the receiving member 132.

A plurality of spline teeth 13 b are formed on the outer periphery of the meshing member 13. A plurality of spline teeth 111 a are formed on the inner periphery of the cylindrical portion 111 in the intermediate shaft 11. The spline teeth 13 b of the meshing member 13 and the spline teeth 111 a of the intermediate shaft 11 mesh at a first position where the meshing member 13 is separated from the receiving member 132, and mesh at a second position where the meshing member 13 approaches the receiving member 132. Canceled. In FIG. 4, showing a state in which the spline teeth 111a are engaged spline teeth 13b and the intermediate shaft 11 of the meshing member 13 above the rotation axis O _2, the spline teeth of the meshing member 13 below the rotation axis O ₂ 13 shows a state in which the meshing between 13b and the spline teeth 111a of the intermediate shaft 11 is released.

  When the spline teeth 13b of the meshing member 13 and the spline teeth 111a of the intermediate shaft 11 mesh with each other, the intermediate shaft 11 and the inner shaft 12 are connected so as not to be relatively rotatable. That is, the propeller shaft 20 and the rear wheels 205L and 205R are connected in the four-wheel drive state. On the other hand, when the meshing between the spline teeth 13b of the meshing member 13 and the spline teeth 111a of the intermediate shaft 11 is released, the connection between the propeller shaft 20 and the rear wheels 205L and 205R is cut off. That is, the meshing member 13 and the intermediate shaft 11 together with the meshing clutch 23 constitute a “connection mechanism” of the present invention.

  An annular first friction member 14 is fitted on the outer periphery of the cylindrical portion 111 of the intermediate shaft 11. The first friction member 14 integrally includes a disc-shaped main body 141 and a flange 142 that protrudes in the axial direction from the outer peripheral end of the main body 141. The main body 141 has an inner peripheral end engaged with a plurality of spline protrusions 111 b formed on the outer peripheral surface of the cylindrical portion 111. Thereby, the first friction member 14 is not rotatable relative to the intermediate shaft 11 and is movable in the axial direction. The inner peripheral surface 142a of the flange 142 has a tapered shape with an inner diameter that increases toward the tip end in the axial direction.

  The first friction member 14 is urged by the elastic member 151 to the side opposite to the shaft portion 110 of the intermediate shaft 11, and comes into contact with a step portion formed on the tube portion 111, thereby moving the first friction member 14 toward the distal end side of the tube portion 111. The movement in the axial direction is restricted. The elastic member 151 is configured by arranging a plurality of disc springs 151 a in the axial direction, and is arranged in a state compressed in the axial direction between the first friction member 14 and the annular body 152 fixed to the cylindrical portion 111. ing.

  The first friction member 14 frictionally slides with the second friction member 16 disposed so as not to rotate relative to the inner shaft 12 and to be movable in the axial direction, and generates a rotational force between the intermediate shaft 11 and the inner shaft 12. introduce. That is, the first friction member 14 and the second friction member 16 constitute a friction clutch 1a. The friction clutch 1 a is an aspect of the “friction clutch” of the present invention capable of transmitting a rotational force for synchronizing the meshing clutch 23 with the propeller shaft 20.

  The second friction member 16 integrally includes a disk-shaped main body portion 161 and a flange portion 162 that protrudes in the axial direction from the outer peripheral end portion of the main body portion 161. The main body 161 has an inner peripheral end engaged with a plurality of spline protrusions 12 a formed on the outer peripheral surface of the inner shaft 12. Thereby, the second friction member 16 is not rotatable relative to the inner shaft 12 and is movable in the axial direction. The outer peripheral surface 162a of the collar portion 162 has a tapered shape in which the outer diameter is reduced toward the tip portion in the axial direction.

  The second friction member 16 moves in the axial direction together with the meshing member 13 with the side surface of the main body portion 161 coming into contact with the meshing member 13. When the second friction member 16 moves toward the first friction member 14, the outer peripheral surface 162 a of the flange portion 162 comes into surface contact with the inner peripheral surface 142 a of the flange portion 142 of the first friction member 14. At this time, the elastic member 151 urging the first friction member 14 toward the second friction member 16 is compressed, and the first friction member 14 is pressed against the second friction member 16 by the restoring force of the elastic member 15. . Thereby, the inner peripheral surface 142a of the flange 142 of the first friction member 14 and the outer peripheral surface 162a of the flange 162 of the second friction member 16 are in frictional contact.

  The second friction member 16 and the meshing member 13 are positioned by the positioning mechanism 3 having the electromagnetic coil 31, the armature 4, and the cam member 5. The electromagnetic coil 31 is supplied with a coil current from the control device 9 and generates a magnetic force. The armature 4 is attracted toward the electromagnetic coil 31 by the magnetic force when the electromagnetic coil 31 is energized. The electromagnetic coil 31 is held by an annular yoke 30. A disc spring 32 is disposed between the yoke 30 and the armature 4 to bias the armature 4 away from the electromagnetic coil 31.

  The armature 4 is elastically pressed in a direction away from the yoke 30 by the disc spring 32. When the electromagnetic coil 31 is not energized, the armature 4 abuts against the receiving portion 102c of the second housing member 102 by the pressing force of the disc spring 32. When the electromagnetic coil 31 is energized, the armature 4 is attracted to the yoke 30 by the magnetic force. It is done. Further, the rotation of the armature 4 with respect to the second housing member 102 and the yoke 30 is restricted by a plurality of pins 33 inserted into the pin insertion holes 4b.

  The positioning mechanism 3 includes a first position where the spline teeth 111a of the intermediate shaft 11 and the spline teeth 13b of the meshing member 13 mesh, an inner peripheral surface 142a of the collar 142 of the first friction member 14 and a collar of the second friction member 16. The meshing member 13 and the second friction member 16 can be positioned at a second position where the outer peripheral surface 162a of the 162 is in frictional contact and at a plurality of positions between the first position and the second position. Next, the configuration and operation of the positioning mechanism 3 will be described with reference to FIGS.

Figure 5 shows the cam member. 5, (a) shows the plan view as taken along a cam member 5 from the armature 4 side in the rotation axis O _2, (b) is a perspective view showing a part of the cam member 5 It is.

  The cam member 5 is an annular member externally fitted to the inner shaft 12, and the axial end surface 5a on the second friction member 16 side is formed to be a flat surface. A needle roller bearing 6 (shown in FIG. 4) is disposed between the axial end surface 5 a and the second friction member 16. The cam member 5 receives the biasing force of the return spring 131 via the needle roller bearing 6 and moves in the axial direction together with the meshing member 13 and the second friction member 16.

  The cam member 5 includes six locked portions (first to sixth locked portions 51 to 56) having different distances from the axial end surface 5a, and the sixth locked portion 56 in the circumferential direction. A wall portion 57 adjacent to is formed. In the present embodiment, six sets of first to sixth locked portions 51 to 56 and a wall portion 57 are formed on the cam member 5. The axial end surfaces 51 a, 52 a, 53 a, 54 a, 55 a, 56 a of the cam member 5 in the first to sixth locked portions 51 to 56 are closer to the wall portion 57 toward the axial end surface 5 a. Inclined to shorten.

FIG. 6 is a perspective view showing the armature 4. The armature 4 includes an annular plate-shaped main body 40 in which a through hole 4a through which the inner shaft 12 is inserted is formed at the center, and a plurality of (this embodiment) projecting from the inner peripheral surface of the through hole 4a toward the center of the main body 40 In this embodiment, six pressing projections 41 are integrally provided. In the main body 40, pin insertion holes 4b through which a plurality of pins 33 (shown in FIG. 4) are inserted around the through hole 4a are formed at four locations. Pressing projections 41, parallel first through opposing surfaces 41a that faces the axial end surface 51a~56a the engaged portion 51 to 56 of the sixth cam member 5, in the thickness direction (rotation axis _{O 2} of the main body 40 A slanted surface that is slanted with respect to a certain direction).

FIG. 7 is a perspective view showing a plurality of locking portions 19 provided in the second housing member 102. The second housing member 102 is formed with a through hole 102d through which the inner shaft 12 is inserted. A plurality of locking portions 19 protrudes in the cam member 5 side along the inner circumferential surface of the through-hole 102d protrudes inwardly, and the rotation axis O _2. Engaging portion 19, similarly to the facing surface 41a of the pressing projection 41 of the armature 4, the distal end surface 19a facing the axial end surface 51a~56a the engaged portion 51 to 56 of the cam member 5, the rotation axis _{O 2} It is formed as an inclined surface inclined with respect to a direction parallel to.

  As for the position of the axial end surface 5 a of the cam member 5, any one of the first to sixth locked portions 51 to 56 is locked to the locking portion 19 of the second housing member 102. It depends on what. The cam member 5 rotates a predetermined angle by the axial movement of the armature 4, and the armature 4 reciprocates once by energization of the electromagnetic coil 31, so that the locked portion that is locked by the locking portion 19 makes one round. Deviation in direction. Next, the operation of the positioning mechanism 3 will be described.

  8A to 8D are explanatory views for schematically explaining the operation of the cam member 5 and the armature 4 together with the locking portion 19.

FIG. 8A shows a state in which the locking portion 19 locks the first locked portion 51 of the cam member 5 and the facing surface 41a of the pressing projection 41 of the armature 4 faces the axial end surface 51a. ing. A gap of a distance d ₁ is formed between the pressing protrusion 41 and the side surface 51 b of the first locked portion 51 in the cam member 5. This is energized from the state to the electromagnetic coil 31 rotates and the armature 4 is moved axially, as shown in FIG. 8 (b), together with the cam member 5 is moved in the axial direction together with the armature 4, a distance d ₁ in the circumferential direction To do. At this time, a part of the front end surface 19 a of the locking portion 19 faces the axial end surface 52 a of the second locked portion 52.

FIG. 8C shows a state where the energization of the electromagnetic coil 31 is cut off and the armature 4 is returning to the initial position. In the process in which the armature 4 returns to the initial position, the front end surface 19 a of the locking portion 19 abuts on the axial end surface 52 a of the second locked portion 52. When the armature 4 further moves from this state and returns to the initial position, the cam member 5 is moved as shown in FIG. 8C due to the inclination of the tip end surface 19a of the locking portion 19 and the axial end surface 52a of the second locked portion 52. ) In the circumferential direction by a distance d ₂ (distance between the locking portion 19 and the side surface 52b of the second locked portion 52) as shown in FIG. In this state, the second second locked portion 52 is locked.

  By repeating this operation, the locked portion of the cam member 5 locked to the locking portion 19 sequentially moves in the circumferential direction, and the locking portion 19 locks the sixth locked portion 56. When the armature 4 is further reciprocated once, the locking portion 19 is locked to the first locked portion 51.

Thus, the cam member 5 changes from the state in which the locking part 19 locks the first locked part 51 to the state in which the sixth locked part 56 is locked, so that the cam member 5 moves to the intermediate shaft 11 side. Extruded. Moving the axial distance therebetween of the cam member 5, a distance d ₃ between the axial end surface 5a and the first engaged portion 51 of the cam member 5 shown in FIG. 8 (a), the axial end face 5a This corresponds to the difference between the distance d ₄ between the first and second locked portions 56.

  In the present embodiment, when the locking portion 19 locks the first locked portion 51, the spline teeth 13b of the meshing member 13 and the spline teeth 111a of the intermediate shaft 11 are meshed, and the locking portion 19 is the first. When the sixth locked portion 56 is locked, the inner peripheral surface 142a of the flange 142 of the first friction member 14 and the outer peripheral surface 162a of the flange 162 of the second friction member 16 are in frictional contact.

(Control method of the driving force transmission system 201 by the control device 9)
Next, a method for controlling the driving force transmission system 201 by the control device 9 will be described with reference to FIGS.

  FIG. 9 is a flowchart showing a part of processing executed by the control unit 92 of the control device 9 when the above-described third operation mode is selected. The control unit 92 repeatedly executes the process shown in this flowchart at a predetermined cycle. In the following description, the state in which the meshing clutch 23 is in the connected state and the meshing member 13 and the intermediate shaft 11 in the driving force transmitting device 1 are in mesh is referred to as “connected state”, and the meshing clutch 23 is in the disconnected state. A state in which the engagement member 13 and the intermediate shaft 11 in the driving force transmission device 1 are not engaged is referred to as a “disconnected state”.

  When the control unit 92 transmits the rotational force to the propeller shaft 20 by the friction clutch 1a of the driving force transmission device 1 to synchronize the mesh clutch 23 in order to transition from the disconnected state to the connected state, the synchronization is completed. The time required until the time is calculated (step S10). This required time is calculated based on at least an index value related to temperature. Hereinafter, the required time obtained in step S10 is referred to as “T_sync”. Details of the arithmetic processing in step S10 will be described later.

  Note that the arithmetic processing in step S10 is executed regardless of whether the driving force transmission system 201 is in a connected state or a disconnected state. That is, if the driving force transmission system 201 is in the connected state, the propeller shaft 20 is rotating, but in step S10, it is assumed that the driving force transmission system 201 is in a disconnected state in which the driving force is not transmitted to the propeller shaft 20, The time required for 23 synchronization is calculated.

  Next, the control unit 92 determines whether or not T_sync is greater than or equal to a first predetermined value (step S11). This first predetermined value is, for example, 2 seconds. When T_sync is greater than or equal to the first predetermined value (S11: Yes), the controller 92 determines whether or not the driving force transmission system 201 is in a disconnected state (step S12). When the driving force transmission system 201 is not in the disconnected state (when in the connected state; S12: No), the control unit 92 performs the processing of the flowchart shown in FIG. 9 without executing the switching determination processing in step S17 described later. finish. That is, the connected state is maintained regardless of the vehicle running state. That is, in the four-wheel drive state, when it is determined that the time required to synchronize the meshing clutch 23 after the rotation of the propeller shaft 20 is greater than or equal to a predetermined value in the four-wheel drive state, the control unit 92 relates to the vehicle running state. First, the engaged state of the meshing clutch 23 is maintained.

  When the driving force transmission system 201 is in the disconnected state in the determination in step S12 (S12: Yes), the control unit 92 determines whether or not the vehicle speed of the four-wheel drive vehicle 200 is equal to or less than a predetermined value (step S12). S13). This predetermined value is determined in accordance with the vehicle speed when the rotation speed of the propeller shaft 20 cannot be increased to the extent that the meshing clutch 23 is synchronized depending on the friction torque generated by the friction clutch 1a of the driving force transmission device 1. The speed is 60 to 70 km / h.

  If it is determined in step S13 that the vehicle speed is equal to or lower than the predetermined value (S13: Yes), the control unit 92 executes transition control from the disconnected state to the connected state (step S14). That is, when the control unit 92 synchronizes the mesh clutch 23 in the two-wheel drive state, when it is determined that the time required for the synchronization is equal to or greater than the first predetermined value, the operation of the friction clutch 1a causes the propeller shaft 20 to operate. Rotate. Details of the transition control in step S14 will be described later.

  On the other hand, if it is determined in step S13 that the vehicle speed is not less than or equal to the predetermined value (S13: No), the control unit 92 does not execute the transition control from the disconnect state to the connect state (step S14), as shown in FIG. The process of the flowchart ends. That is, when it is determined that T_sync is equal to or higher than the first predetermined value, the control unit 92 operates the friction clutch 1a of the driving force transmission device 1 on the condition that the vehicle speed is equal to or lower than the predetermined value.

  In addition, when T_sync is not equal to or greater than the first predetermined value in the determination of step S11 (S11: No), the control unit 92 determines whether T_sync is equal to or greater than the second predetermined value (step S15). The second predetermined value is shorter than the first predetermined value, for example, 1 to 1.5 seconds. When T_sync is equal to or greater than the second predetermined value (S15: Yes), the control unit 92 relaxes the conditions for operating the friction clutch 1a in the switching determination process in step S17 described later (step S16), and T_sync is The friction clutch 1a is actuated at an early stage as compared with the case where it is less than the second predetermined value.

  On the other hand, when T_sync is not equal to or greater than the second predetermined value (S15: No), the control unit 92 switches from the disconnected state to the connected state or executes the process of step S16 or from the connected state to the disconnected state. A switching determination process (step S17) for determining whether to switch to is executed. That is, when T_sync is equal to or greater than the second predetermined value, the switching determination process (step S17) is performed after changing the conditions for operating the friction clutch 1a in the switching determination process of step S17 by the process of step S16. When T_sync is less than the second predetermined value, the switching determination process in step S17 is executed without performing the process in step S16.

  In addition, when the conditions for operating the friction clutch 1a are changed by the process of step S16, the change of the conditions is effective only in one switching determination process (step S17) performed immediately after that. Details of the switching determination process in step S17 will be described later.

  Next, the control unit 92 performs transition control to the disconnected state or connected state based on the determination result of step S17 (step S18). That is, in the switching determination process in step S17, when it is determined that the disconnection state should be switched to the connected state, the driving force transmission device 1, the torque coupling 28, and the meshing clutch 23 are controlled to control the driving force transmission system. Switch 201 to the connected state. When it is determined that the connected state should be switched to the disconnected state, the driving force transmission device 1, the torque coupling 28, and the meshing clutch 23 are similarly controlled to switch the driving force transmission system 201 to the disconnected state. .

  The specific processing content of the control unit 92 when switching from the disconnected state to the connected state is the same as the processing content of step S14. Further, when switching from the connected state to the disconnected state, the transmission torque by the torque coupling 28 is reduced and the transmission of the driving force through the propeller shaft 20 is cut off, and then the meshing clutch 23 is brought into the coupling cutoff state, and the meshing member 13 and the intermediate shaft 11 are disengaged.

(Calculation processing of time required for synchronization of meshing clutch 23 (T_sync))
Here, the details of the process of step S10 of the flowchart will be described. In this process, in consideration of the viscosity of the lubricating oil that changes depending on the temperature, the propeller shaft 20 in the rotation stop state is rotated by the torque transmitted by the friction clutch 1a of the driving force transmission device 1, and the meshing clutch 23 is rotated. This is a process for calculating the time required for synchronization.

  This calculation process is executed based on the rotational resistance of the propeller shaft 20, the front wheel side gear mechanism 26, and the rear wheel side gear mechanism 27 and the maximum torque that can be transmitted by the friction clutch 1a of the driving force transmission device 1. In calculating the rotational resistance of the propeller shaft 20, the front wheel side gear mechanism 26, and the rear wheel side gear mechanism 27, at least an index value related to temperature is taken into consideration.

  For example, as shown in FIG. 2, a lubricating oil L that lubricates the rear wheel side gear mechanism 27 is sealed inside the differential carrier 220, and the viscosity of the lubricating oil L varies greatly depending on its temperature. For this reason, the rotational resistance of the rear wheel side gear mechanism 27 changes with temperature. Further, as the viscosity of the lubricating oil L changes, the rotational resistance of the pair of bearings 220b and 220c lubricated by the lubricating oil L also changes. Further, also in the front wheel side gear mechanism 26 and the propeller shaft 20, as in the rear wheel side gear mechanism 27, the rotational resistance changes due to the temperature change of the viscosity of the lubricating oil.

  The controller 92 detects or estimates the temperature of these lubricating oils, and calculates the rotational resistance of the propeller shaft 20, the front wheel side gear mechanism 26, and the rear wheel side gear mechanism 27 based on the result. The temperature of the lubricating oil can be detected based on, for example, a temperature sensor provided in the vicinity of the differential carrier 220 and the front wheel side gear mechanism 26. It is also possible to estimate the temperature of the lubricating oil based on the integrated value within the past predetermined time of the driving force transmitted to the rear wheels 205L and 205R via the propeller shaft 20.

  The maximum torque that can be transmitted by the friction clutch 1 a of the driving force transmission device 1 is specifically the friction clutch 1 a when the sixth locked portion 56 of the cam member 5 is locked to the locking portion 19. Is the transmission torque. Note that when the propeller shaft 20 is rotated from the rotation stopped state, the main clutch 283 is configured so that the torque that can be transmitted in the torque coupling 28 is larger than the torque transmitted by the friction clutch 1 a of the driving force transmission device 1. It shall be concluded.

  Further, in the present embodiment, the transmission torque when the first friction member 14 and the second friction member 16 frictionally slide in the friction clutch 1a is substantially constant, but for example, the transmission torque according to the supplied current When the propeller shaft 20 is rotated by a variable friction clutch, a required time (T_sync) required for synchronization of the meshing clutch 23 is calculated based on the maximum torque that can be transmitted by the friction clutch.

(Transition control from disconnected state to connected state)
Next, details of the processing in step S14 in the flowchart will be described. In the transition control from the disconnected state to the connected state, when the four-wheel drive vehicle 200 is traveling in the third operation mode, the propeller shaft 20 in the rotation stop state is rotated, and then the meshing clutch 23 is connected and driven. This is a process of meshing the meshing member 13 and the intermediate shaft 11 in the force transmission device 1.

  In this process, first, the energization of the electromagnetic coil 31 of the driving force transmission device 1 causes the locking portion 19 to lock the sixth locked portion 56. As a result, the first friction member 14 and the second friction member 16 frictionally slide, and the rotational force transmitted from the right rear wheel 205R to the axle shaft 29R passes through the inner shaft 12, the friction clutch 1a, and the intermediate shaft 11. Is transmitted to the rear differential 22 and further transmitted from the rear differential 22 to the propeller shaft 20 via the rear wheel side gear mechanism 27 and the torque coupling 28. As a result, the rotation of the propeller shaft 20 is accelerated, and the rotation of the second rotation member 232 of the meshing clutch 23 connected to the propeller shaft 20 via the front wheel side gear mechanism 26 is synchronized with the rotation of the first rotation member 231. To do.

  After confirming the rotation synchronization between the first rotating member 231 and the second rotating member 232, the control unit 92 energizes the actuator that moves the sleeve 233 forward and backward, and causes the spline teeth 233 a of the sleeve 233 to move to the second rotating member 232. The spline teeth 231a and the first rotating member 231 are engaged with the spline teeth 232a. As a result, the meshing clutch 23 is engaged, and the driving force of the engine 202 can be transmitted to the rear wheels 205L and 205R via the propeller shaft 20. In addition, the rotational speed of the 1st rotation member 231 can be calculated | required based on the wheel speed of the front wheels 204L and 204R, for example. Further, the rotational speed of the second rotating member 232 can be obtained based on, for example, the detected value of the rotational speed sensor of the propeller shaft 20 and the gear ratio of the front wheel side gear mechanism 26.

  Further, the control unit 92 energizes the electromagnetic coil 31 of the driving force transmission device 1 after the meshing clutch 23 is connected, and the first locked portion 51 of the cam member 5 is locked to the locking portion 19. State As a result, the meshing member 13 and the intermediate shaft 11 mesh with each other, and the intermediate shaft 11 and the axle shaft 29R on the rear wheel 205R side are coupled so as to be able to transmit driving force. Thus, the transition from the disconnected state to the connected state is completed.

(Switching judgment process)
Next, details of the processing in step S17 of the flowchart will be described. This switching determination process is a process of determining whether to switch to the connected state when in the disconnected state and whether to switch to the disconnected state when in the connected state.

The controller 92 performs this determination process based on the difference between the rotational speeds of the front and rear wheels and the acceleration operation amount by the driver. More specifically, the threshold for the rotational speed difference between the front and rear wheels and N _1, if the threshold for the acceleration operation quantity by the driver and S _1, when the rotational speed difference is the threshold value N ₁ or more or the driver of the front and rear wheels acceleration operation amount by is determined to be in the connected state when the threshold value S ₁ or more, a threshold N ₁ is rotated speed difference between the front and rear wheels, and when the acceleration operating amount by the driver is less than the threshold value S ₁ It is determined that the disconnect state should be established. It should be noted that it may be determined whether or not the disconnection state and the connection state should be switched based on the difference between the rotational speeds of the front and rear wheels and the vehicle travel state amount other than the acceleration operation amount by the driver.

(Process to relax the conditions for operating the friction clutch 1a)
Next, details of the processing in step S16 of the flowchart will be described. In this process, the threshold value in the switching determination process (step S17) is changed, the condition for operating the friction clutch 1a (the condition for transition from the disconnected state to the connected state) is relaxed, and at an earlier stage. This is a process for operating the friction clutch 1a.

This process is a process for reducing the values of the threshold values N ₁ and S ₁ in the switching determination process. More specifically, for example, when the threshold value _{N 1} in (for T_SYNC <second predetermined value) normal is 50 rpm, and 25rpm by changing the threshold value, also, the accelerator threshold _{S 1} during the normal, for example, When the opening degree is 40%, this threshold value is changed to 20%.

FIG. 10 is a graph showing an example of a temporal change in the rotational speed difference between the front and rear wheels (front and rear wheel differential rotation ΔN) when, for example, a slip occurs in the right front wheel 204R. In the switching determination process (step S17), if the rotational speed difference between the front and rear wheels at the normal time determined from the disconnected state when the threshold N ₁ or more and to switch to a connected state, the switching determination at time t ₁ (disconnected state Although determination that to switch to a connected state) is made from, changing the threshold value in the processing of step S16 in _{N 2 (N 2 = N 1} /2), the switching determination at an early time _{t 2} than the time _{t 1} Is made. As a result, when T_sync ≧ second predetermined value, the friction clutch 1a operates earlier than when T_sync <second predetermined value.

  Next, a second process (a process different from the process of the flowchart in FIG. 9) executed by the control unit 92 when the third operation mode is selected will be described with reference to FIG. The process of the flowchart shown in FIG. 11 is executed following the process of the flowchart shown in FIG. 9, for example.

  In the process of this flowchart, the controller 92 first calculates the acceleration of the four-wheel drive vehicle 200 (step S20). This acceleration can be calculated based on temporal changes in the rotational speeds of the front wheels 204L and 204R and the rear wheels 205L and 205R, for example.

  Next, the control unit 92 estimates the vehicle speed of the four-wheel drive vehicle 200 after a predetermined time based on the acceleration obtained in step S20 (step S21). That is, in addition to the vehicle speed at the time of calculation, the vehicle speed of the four-wheel drive vehicle 200 after the predetermined time is estimated by taking into account the speed change when acceleration at the acceleration obtained in step S20 continues for a predetermined time. This predetermined time is, for example, 1 to 5 seconds.

  Next, when synchronizing the meshing clutch 23 at the vehicle speed estimated in Step S21, the control unit 92 calculates a time required for completing the synchronization (Step S22). This calculation process is the same as the process of step S10 in the flowchart shown in FIG. Next, the control unit 92 determines whether or not T_sync is greater than or equal to a first predetermined value (step S23). The first predetermined value is the same value as the first predetermined value in step S11 in the flowchart shown in FIG. 9, and is, for example, 2 seconds. However, the first predetermined value in step S23 may be different from the first predetermined value in step S11.

  Since the determination in step S23 is based on the estimated value of the vehicle speed after the predetermined time obtained in step S21, when the transition from the disconnect state to the connected state is attempted after the predetermined time, the first predetermined in step S23. It is predicted whether or not the synchronization of the meshing clutch 23 is completed within the time.

  When T_sync is greater than or equal to the first predetermined value (S23: Yes), the controller 92 determines whether or not the driving force transmission system 201 is in a disconnected state (step S24). When the driving force transmission system 201 is in the disconnected state (S24: Yes), the control unit 92 executes transition control from the disconnected state to the connected state (step S25). The processing content in step S25 is the same as the processing content in step S14 in the flowchart shown in FIG.

  If the result of determination in step S23 or S24 is No, the process of the flowchart shown in FIG. 11 is terminated without executing the process of step S25.

  In this way, the control unit 92 rotates the propeller shaft 20 by the operation of the friction clutch 1a when it is predicted that T_sync will be equal to or higher than the first predetermined value due to the increase in vehicle speed during acceleration in the disconnected state. .

(Operation and effect of the embodiment)
According to the embodiment described above, the following operations and effects can be obtained.

(1) In the disconnected state, when it is determined that the time required for synchronization of the meshing clutch 23 exceeds the first predetermined value, the friction clutch 1a is operated and the propeller shaft 20 rotates. That is, for example, when it is necessary to shift to the four-wheel drive state due to the occurrence of a slip or the like, the propeller shaft 20 can be rotated in advance, so that the four-wheel drive state can be promptly shifted to Stability can be increased.

(2) When T_sync is equal to or greater than the second predetermined value, the condition of the switching determination process in step S17 is relaxed so that the transition to the connected state is likely to occur, so that the friction clutch 1a is activated early. It becomes possible to quickly shift to the four-wheel drive state.

(3) Since the transition to the connected state in step S14 is performed when the vehicle speed is equal to or lower than a predetermined value, an impact is generated when the friction clutch 1a is operated, giving anxiety to the driver or the like. In addition, excessive wear of the first friction member 14 and the second friction member 16 in the driving force transmission device 1 can be prevented.

(4) When it is predicted that T_sync will be equal to or higher than the first predetermined value due to an increase in the vehicle speed, the propeller shaft 20 is rotated by the operation of the friction clutch 1a and transitions to the connected state. The transition to the connected state can be completed before an excessive amount of time is required for synchronization of the meshing clutch 23.

  As mentioned above, although the control apparatus of the four-wheel drive vehicle of this invention and the control method of the four-wheel drive vehicle were demonstrated based on said embodiment, this invention is not limited to said embodiment, The It is possible to implement in various modes without departing from the gist.

  For example, in the above embodiment, the driving force transmission device 1 is disposed between the rear differential 22 and the axle shaft 29R on the rear wheel 205R side, and the propeller shaft 20 is driven by the transmission torque of the friction clutch 1a of the driving force transmission device 1. However, the present invention is not limited to this. For example, the side gear 221R of the rear differential 22 and the axle shaft 29R on the rear wheel 205R side are directly connected, and the propeller shaft 20 is driven by torque transmitted from the torque coupling 28 that is a friction clutch. The meshing clutch 23 may be synchronized by rotating.

  In the above embodiment, the torque coupling 28 is disposed on the rear side of the propeller shaft 20. However, the torque coupling 28 may be disposed on the front side of the propeller shaft 20.

DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device, 1a ... Friction clutch, 3 ... Positioning mechanism, 4 ... Armature, 4a ... Through-hole, 4b ... Pin insertion hole, 5 ... Cam member, 5a ... Axial end surface, 6 ... Needle roller bearing, DESCRIPTION OF SYMBOLS 9 ... Control apparatus, 10 ... Housing, 11 ... Intermediate shaft, 11a ... Accommodating space, 12 ... Inner shaft, 12a ... Spline protrusion, 13 ... Intermeshing member, 13a ... Spline protrusion, 13b ... Spline tooth, 13c ... Axial hole, DESCRIPTION OF SYMBOLS 14 ... 1st friction member, 15 ... Elastic member, 16 ... 2nd friction member, 19 ... Locking part, 19a ... End surface, 20 ... Propeller shaft, 21 ... Front differential, 22 ... Rear differential, 23 ... Meshing clutch, 24L, 24R ... axle shaft, 26 ... front wheel side gear mechanism, 27 ... rear wheel side gear mechanism, 28 ... torque coupling, 29L, 29R Axle shaft, 30 ... yoke, 31 ... electromagnetic coil, 32 ... disc spring, 33 ... pin, 40 ... main body, 41 ... pressing projection, 41a ... facing surface, 51-56 ... first to sixth locked parts, 51a, 52a, 53a, 54a, 55a, 56a ... axial end face, 57 ... wall part, 91 ... storage part, 92 ... control part, 93 ... current output circuit, 101 ... first housing member, 102 ... second housing member , 102c ... receiving portion, 102d ... through hole, 103 ... bolt, 104, 105 ... ball bearing, 110 ... shaft portion, 111 ... cylindrical portion, 111a ... spline teeth, 111b ... spline protrusion, 112 ... ball bearing, 131 ... return Spring, 132 ... receiving member, 141 ... main body, 142 ... collar, 142a ... inner peripheral surface, 151 ... elastic member, 151a ... disc spring, 152 ... annular body, 161 ... main body, 162鍔 part, 162a, outer peripheral surface, 200, four-wheel drive vehicle, 201, driving force transmission system, 201A, front wheel side driving force transmission system, 201B, rear wheel side driving force transmission system, 202, engine, 203, transmission, 204L 204R ... front wheel, 205L, 205R ... rear wheel, 211L, 211R ... side gear, 212 ... pinion gear, 213 ... gear support member, 214 ... front differential case, 220 ... differential carrier, 220b, 220c ... bearing, 221L, 221R ... side gear, 222 ... pinion gear, 223 ... gear support member, 224 ... rear differential case, 231 ... first rotating member, 231a ... spline teeth, 232 ... second rotating member, 232a ... spline teeth, 233 ... sleeve, 233a ... spline teeth, 233b ... Groove, 234 ... fork, 261 ... pi Nion gear, 262 ... Ring gear, 271 ... Pinion gear, 271a ... Spline engaging portion, 271b ... Gear portion, 271c ... Shaft portion, 272 ... Ring gear, 281 ... Front housing, 281a ... Spline engaging portion, 282 ... Rear housing, 283 ... Main clutch, 283a ... outer clutch plate, 283b ... inner clutch plate, 284 ... electromagnetic clutch mechanism, 284a ... electromagnetic coil, 284b ... armature, 284c ... pilot clutch, 285 ... cam mechanism, 285a ... first cam member, 285b ... first 2 cam member, 285c ... rolling element, 286 ... mounting member, L ... lubricant, O 1 _... rotational axis, O 2 _... rotational axis,

Claims (6)

A four-wheel drive vehicle capable of switching between a four-wheel drive state in which the drive force of the drive source is transmitted to the main drive wheel and the auxiliary drive wheel and a two-wheel drive state in which the drive force of the drive source is transmitted only to the main drive wheel. A control device of
The four-wheel drive vehicle is
A propeller shaft that transmits driving force to the auxiliary driving wheel in the four-wheel driving state;
Including at least one meshing clutch, and disconnecting the propeller shaft from the main drive wheel and the auxiliary drive wheel in the two-wheel drive state; and the propeller shaft and the main drive wheel in the four-wheel drive state; A coupling mechanism capable of coupling the auxiliary drive wheel;
A friction clutch capable of transmitting a rotational force for synchronizing the meshing clutch to the propeller shaft in a state where the coupling mechanism is disconnected;
When the meshing clutch is synchronized in the two-wheel drive state, when it is determined that the time required for the synchronization exceeds the first predetermined value, the propeller shaft is rotated by the operation of the friction clutch. Car control device. In the two-wheel drive state, when it is determined that the required time is equal to or greater than a second predetermined value shorter than the first predetermined value, the condition for operating the friction clutch is relaxed, and the required time Actuating the friction clutch at an early stage as compared with the case where is less than the second predetermined value,
The control device for a four-wheel drive vehicle according to claim 1. When it is determined that the time required for synchronization of the meshing clutch is equal to or greater than the first predetermined value, the friction clutch is operated on condition that the vehicle speed is equal to or lower than the predetermined value;
The control device for a four-wheel drive vehicle according to claim 1 or 2. In the four-wheel drive state, when it is determined that the time required for synchronizing the meshing clutch after the rotation of the propeller shaft is equal to or greater than a predetermined value, the meshing clutch is connected regardless of the vehicle running state. Maintain state,
The control device for a four-wheel drive vehicle according to any one of claims 1 to 3. When it is predicted that the required time will be greater than or equal to a predetermined value due to an increase in vehicle speed during acceleration when the connection mechanism is disconnected, the propeller shaft is rotated by operating the friction clutch.
The control device for a four-wheel drive vehicle according to any one of claims 1 to 4. A four-wheel drive vehicle capable of switching between a four-wheel drive state in which the drive force of the drive source is transmitted to the main drive wheel and the auxiliary drive wheel and a two-wheel drive state in which the drive force of the drive source is transmitted only to the main drive wheel. Control method,
The four-wheel drive vehicle is
A propeller shaft that transmits driving force to the auxiliary driving wheel in the four-wheel driving state;
Including at least one meshing clutch, and disconnecting the propeller shaft from the main drive wheel and the auxiliary drive wheel in the two-wheel drive state; and the propeller shaft and the main drive wheel in the four-wheel drive state; A coupling mechanism capable of coupling the auxiliary drive wheel;
A friction clutch capable of transmitting a rotational force for synchronizing the meshing clutch to the propeller shaft in a state where the coupling mechanism is disconnected;
When the meshing clutch is synchronized in the two-wheel drive state, when it is determined that the time required for the synchronization exceeds the first predetermined value, the propeller shaft is rotated by the operation of the friction clutch. How to control the car.

Images