JP2017026137A - Clutch device and control method of clutch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clutch device which can make the discharge pressure of a working fluid from a hydraulic pump quickly approximate target pressure even if a temperature of the working fluid is changed, and a control method of the clutch device.SOLUTION: A drive force transmission device 1 comprises: first and second friction clutches 12A, 12B; a piston 122 which presses the first and second friction clutches 12A, 12B; a hydraulic pump 51 which supplies a working fluid to a cylinder chamber 130d of the piston 122; an electric motor 52 for driving the hydraulic pump 51; and a control part 10 which controls the electric motor 52, and adjusts the discharge pressure of the hydraulic pump 51. The control part 10 has: feedback control means 102 which controls the feedback of the electric motor 52 by using a correction value based on a difference between a target value and an actual value of the discharge pressure of the hydraulic pump 51; working fluid temperature estimation means 105 which estimates a temperature of a working fluid; and gain adjusting means 103 which changes a correction amount of feedback control according to the estimated temperature of the working fluid.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a clutch device including a friction clutch that receives a pressing force by hydraulic pressure and generates a friction force between friction members, and a control method of the clutch device.

  2. Description of the Related Art Conventionally, a clutch device including a friction clutch that receives a pressing force by hydraulic pressure and generates a friction force between friction members is used in, for example, a four-wheel drive vehicle that can switch between a four-wheel drive state and a two-wheel drive state. (For example, refer to Patent Document 1).

  The four-wheel drive vehicle described in Patent Document 1 is discharged from a friction clutch in which a plurality of friction materials are stacked, an electric motor controlled by a control unit, a hydraulic pump driven by the electric motor, and a hydraulic pump. It has a piston that receives the hydraulic pressure of the hydraulic oil and presses the friction clutch, and a housing in which the piston is housed and a piston chamber into which the hydraulic oil is introduced. The friction clutch is disposed between the propeller shaft and the rear differential unit.

  In this four-wheel drive vehicle, when hydraulic oil is not supplied to the friction clutch, the driving force of the engine is transmitted only from the transmission to the front wheel side via the front differential unit, and is in a two-wheel drive state. On the other hand, when the hydraulic pump is rotationally driven by the electric motor and hydraulic oil is supplied to the piston chamber, torque transmitted by the frictional force generated by pressing the plurality of friction materials is distributed to the rear wheel side. It becomes a four-wheel drive state.

  In addition, the four-wheel drive vehicle described in Patent Document 1 prevents the hydraulic oil from increasing in viscosity when the temperature of the hydraulic oil is low and the torque transmitted by the friction clutch from becoming excessive. It is configured to measure or estimate temperature.

International Publication No. 2014/125926 (Specification Paragraphs [0003], [0029], [0044])

  It has been confirmed by the present inventors that when the viscosity changes due to the temperature change of the hydraulic oil, the controllability of the electric motor that drives the hydraulic pump is also affected. In other words, when the temperature of the hydraulic oil increases, the viscosity of the hydraulic oil decreases and the rotational resistance of the hydraulic pump decreases, whereas when the temperature of the hydraulic oil decreases, the viscosity of the hydraulic oil increases and the rotational resistance of the hydraulic pump decreases. Get higher. For this reason, if the electric motor is controlled in the same manner when the temperature of the hydraulic oil is low and high, it may take a long time until the discharge pressure from the hydraulic pump converges to the target value.

  The present invention has been made in view of the above circumstances, and its purpose is to quickly bring the discharge pressure of the hydraulic oil from the hydraulic pump close to the target pressure even when the temperature of the hydraulic oil changes. An object of the present invention is to provide a clutch device and a control method of the clutch device.

  In order to achieve the above-described object, the present invention provides a friction clutch that receives a pressing force to generate a friction force between friction members, a piston that receives hydraulic pressure to press the friction clutch, and causes the hydraulic pressure to act on the piston. A hydraulic chamber; a hydraulic pump that supplies hydraulic oil to the hydraulic chamber; an electric motor that drives the hydraulic pump; and a controller that controls the electric motor to adjust a discharge pressure of the hydraulic pump, A control unit that feedback-controls the electric motor with a correction value based on a deviation between a target value and an actual value of the discharge pressure of the hydraulic pump so that the discharge pressure of the hydraulic pump becomes a target pressure; There is provided a clutch device having a correction amount adjusting means for changing a correction amount by the feedback control in accordance with the temperature of the hydraulic oil.

  In order to achieve the above object, the present invention provides a friction clutch that receives a pressing force to generate a frictional force between friction members, a piston that receives hydraulic pressure to press the friction clutch, and the hydraulic pressure applied to the piston. A method for controlling a clutch device, comprising: a hydraulic chamber to be operated; a hydraulic pump that supplies hydraulic oil to the hydraulic chamber; and an electric motor that drives the hydraulic pump, wherein a discharge pressure of the hydraulic pump is a target pressure The electric motor is feedback controlled with a correction value based on a deviation between a target value and an actual value of the discharge pressure of the hydraulic pump so that the correction amount by the feedback control is changed according to the temperature of the hydraulic oil. A method for controlling a clutch device is provided.

  According to the clutch device and the control method of the clutch device according to the present invention, it is possible to quickly bring the discharge pressure of the hydraulic oil from the hydraulic pump close to the target pressure even when the temperature of the hydraulic oil changes.

1 is a configuration diagram illustrating a schematic configuration of a four-wheel drive vehicle including a clutch device according to a first embodiment of the present invention. The structural example of a driving force interrupting device is shown, (a) is sectional drawing of a driving force interrupting device, (b) is explanatory drawing which shows typically the meshing part of a driving force interrupting device. It is sectional drawing which shows the specific example of the structure of a driving force transmission apparatus. It is principal part sectional drawing which shows the structure of a 1st friction clutch and its periphery. It is a block diagram which shows typically the structural example of a hydraulic circuit with the control part which controls a hydraulic circuit. It is a graph which shows an example of the relationship between the temperature and viscosity of hydraulic oil. It is a graph which shows an example of the relationship between the torque of an electric motor, and rotation speed. It is a graph which shows an example of the relationship information which shows the relationship between the value which remove | divided the electric current value of the electric motor by the rotation speed, and the temperature of hydraulic fluid. It is a control block diagram which shows the structural example of the control system of an electric motor. It is a graph which shows an example of the relationship between the temperature of hydraulic fluid, and the gain used for feedback control in a feedback control part. It is a block diagram which shows typically the control part which concerns on 2nd Embodiment with the structural example of a hydraulic circuit. It is a control block diagram which shows the structural example of the control system of the electric motor which concerns on 2nd Embodiment. It is a flowchart which shows the specific example of the process which the hydraulic oil temperature estimation means which concerns on 2nd Embodiment performs with one calculation period. It is a graph which shows the relationship between the temperature of an electric motor in case motor current is constant, and the output torque of an electric motor. It is a graph which shows an example of the some hydraulic fluid temperature related information which the hydraulic fluid temperature estimation means which concerns on 3rd Embodiment memorize | stores.

[First Embodiment]
FIG. 1 is a configuration diagram showing a schematic configuration of a four-wheel drive vehicle including a driving force transmission device as a clutch device according to a first embodiment of the present invention.

(Overall configuration of a four-wheel drive vehicle)
The four-wheel drive vehicle 200 includes an engine 202 as a drive source that generates driving force for traveling, a transmission 203, front wheels 204L and 204R as a pair of left and right main drive wheels, and a rear as a pair of left and right auxiliary drive wheels. Wheels 205L and 205R, a driving force transmission system 201 capable of transmitting the driving force of the engine 202 to the front wheels 204L and 204R and the rear wheels 205L and 205R, and the control unit 10 are provided. In the present embodiment, “L” and “R” in each symbol are used to mean the left side and the right side with respect to the forward direction of the vehicle.

  The 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 state in which the drive force of the engine 202 is transmitted only to the front wheels 204L and 204R. And can be switched. That is, the driving force of the engine 202 is transmitted to the front wheels 204L and 204R that are the main driving wheels in the two-wheel driving state and the four-wheel driving state, and the rear wheels 205L and 205R that are auxiliary driving wheels are the four-wheel driving state. Only the driving force of the engine 202 is transmitted.

  In this embodiment, the case where an engine that is an internal combustion engine is applied as a drive source will be described. However, the present invention is not limited to this, and a combination of an engine and a high-output electric motor such as an IPM (Interior Permanent Magnet Synchronous) motor is used. A drive source may be comprised, and a drive source may be comprised only by a high output electric motor.

  The driving force transmission system 201 is disposed on a driving force transmission path from the transmission 203 side to the rear wheels 205L and 205R side in the four-wheel drive vehicle 200, and is mounted on a vehicle body (not shown) of the four-wheel drive vehicle 200. .

  The driving force transmission system 201 includes a driving force transmission device 1, a propeller shaft 2, a driving force interrupting device 3, a front differential 4, and gear mechanisms 44 and 11. The two-wheel drive state and the two-wheel drive state can be switched to the four-wheel drive state. The driving force transmission device 1 is an aspect of the clutch device of the present invention.

  The front differential 4 includes a front differential case 40, a pinion shaft 41 that rotates integrally with the front differential case 40, a pair of pinion gears 42 that are pivotally supported by the pinion shaft 41, and a pair that meshes with the pair of pinion gears 42 with their gear axes orthogonal to each other. The side gear 43 is disposed between the transmission 203 and the driving force interrupting device 3. One side gear 43 of the pair of side gears 43 is connected to a front wheel side axle shaft 206L, and the other side gear 43 is connected to a front wheel side axle shaft 206R.

  The engine 202 drives the front wheels 204L and 204R by outputting a driving force to the axle shafts 206L and 206R on the front wheel side via the transmission 203 and the front differential 4. The engine 202 outputs the driving force to the rear wheel axle shafts 207L and 207R via the transmission 203, the driving force interrupting device 3, the propeller shaft 2, and the driving force transmission device 1, whereby the rear wheels 205L and 205R are output. Drive. The propeller shaft 2 is disposed between the driving force transmission device 1 and the driving force interrupting device 3 and transmits the driving force in the front-rear direction of the four-wheel drive vehicle 200.

  A front wheel side gear mechanism 44 including a drive pinion 441 and a ring gear 442 that mesh with each other is disposed at the front wheel side end of the propeller shaft 2. The drive pinion 441 is connected to the front end portion of the propeller shaft 2, and the ring gear 442 meshes with the drive pinion 441 with the gear axis being orthogonal.

(Configuration of driving force interrupting device)
FIG. 2 shows a configuration example of the driving force interrupting device 3, (a) is a sectional view of the driving force interrupting device 3, and (b) is an explanatory view schematically showing a meshing portion of the driving force interrupting device 3. . In FIG. 2A, the upper half range of the driving force interrupting device 3 with respect to the rotational axis O of the front differential case 40 is illustrated.

  The driving force interrupting device 3 includes a meshing clutch 30 constituted by first to third rotating members 31 to 33 that rotate coaxially with the front differential case 40, and an actuator 300 that operates the meshing clutch 30. The actuator 300 shafts the third rotating member 33 of the meshing clutch 30 by the torque of the electric motor 34, the speed reducing mechanism 35 that decelerates the rotation of the output shaft 341 of the electric motor 34, and the torque of the electric motor 34 decelerated by the speed reducing mechanism 35. And a moving mechanism 36 for moving in the direction. The electric motor 34 is operated by a current supplied from the control unit 10. The actuator 300 is controlled by the control unit 10.

  The first rotating member 31 of the meshing clutch 30 is fixed to the axial end of the front differential case 40, and the second rotating member 32 is fixed to the ring gear 442 of the gear mechanism 44. The third rotating member 33 is relatively movable in the axial direction with respect to the first rotating member 31 and the second rotating member 32.

  The first rotating member 31 has an annular shape through which an axle shaft 206R on the right front wheel side is inserted on the inner peripheral side thereof, and a plurality of spline teeth formed on the outer peripheral surface so as to extend in parallel with the rotational axis O of the front differential case 40. 311. Concave portions 310 are formed between a pair of spline teeth 311 adjacent to each other in the circumferential direction among the plurality of spline teeth 311. The second rotating member 32 is formed in a cylindrical shape through which the axle shaft 206 </ b> R on the right front wheel side is inserted on the inner peripheral side, and is relatively rotatable coaxially with the first rotating member 31. The second rotating member 32 has a plurality of spline teeth 321 formed on the outer peripheral surface thereof so as to extend in parallel with the rotation axis O of the front differential case 40. Concave portions 320 are formed between a pair of spline teeth 321 adjacent in the circumferential direction among the plurality of spline teeth 321.

  The third rotating member 33 is a sleeve-like connecting member disposed on the outer peripheral side of the first rotating member 31 and the second rotating member 32. A plurality of spline teeth 311 that can be engaged with a plurality of spline teeth 311 of the first rotation member 31 and a plurality of spline teeth 321 of the second rotation member 32 are formed on the inner peripheral surface of the third rotation member 33. Yes.

  In the present embodiment, the third rotating member 33 always meshes with the second rotating member 32 and can move in the axial direction with respect to the second rotating member 32. More specifically, the plurality of spline teeth 331 of the third rotating member 33 are engaged with the recess 320 of the second rotating member 32, and the third rotating member 33 is pivoted with respect to the second rotating member 32 while maintaining this engaged state. The direction is movable.

  Further, when the third rotating member 33 is moved toward the first rotating member 31 by the moving mechanism 36, the plurality of spline teeth 331 as the convex portions of the third rotating member 33 mesh with the concave portions 310 of the first rotating member 31. The first rotating member 31 is connected to the first rotating member 31 so as not to be relatively rotatable. Accordingly, the first rotating member 31 and the second rotating member 32 are connected to each other through the third rotating member 33 so as not to be relatively rotatable, and the driving force of the engine 202 is transmitted from the first rotating member 31 to the second rotating member 32. It becomes possible. On the other hand, when the third rotating member 33 is separated from the first rotating member 31, the meshing between the plurality of spline teeth 331 of the third rotating member 33 and the recess 310 of the first rotating member 31 is released, and the first rotating member 31 The second rotation member 32 can be relatively rotated. As a result, transmission of the driving force from the first rotating member 31 to the second rotating member 32 is interrupted.

  The reduction mechanism 35 includes a pinion gear 351 that rotates integrally with the output shaft 341 of the electric motor 34, a large-diameter gear portion 352a that meshes with the pinion gear 351, and a small-diameter gear portion 352b that rotates integrally with the large-diameter gear portion 352a. 352. The moving mechanism 36 has a linear motion shaft 361 having rack teeth 361 a meshing with the small diameter gear portion 352 b of the reduction gear 352, and a shift fork 362 fixed to the linear motion shaft 361. The third rotating member 33 is formed with an annular groove 332 on the outer peripheral surface in which the shift fork 362 is slidably fitted.

  When the output shaft 341 of the electric motor 34 rotates, the rotation is decelerated by the speed reduction mechanism 35, and the linear motion shaft 361 moves parallel to the rotation axis O of the front differential case 40. As the linear movement shaft 361 moves, the connection position where the third rotating member 33 meshes with the first rotating member 31 and the second rotating member 32, meshes with the second rotating member 32, and meshes with the first rotating member 31. Move between no unconnected positions.

(Configuration of driving force transmission device)
As shown in FIG. 1, the driving force transmission apparatus 1 adjusts the rear wheel side gear mechanism 11 to which the driving force is transmitted from the propeller shaft 2 and the driving force transmitted by the gear mechanism 11 to adjust the axle shaft 207L. , 207R, the first and second friction clutches 12A, 12B, the housing 13 housing the first and second friction clutches 12A, 12B and the gear mechanism 11, the first and second friction clutches 12A, The hydraulic circuit 5 supplies the hydraulic pressure to 12B, and the control unit 10 controls the hydraulic circuit 5.

  The gear mechanism 11 includes a pinion gear 110 and a ring gear 111 that mesh with each other with their gear axes orthogonal to each other, and a center shaft 112 that rotates integrally with the ring gear 111. The center shaft 112 has a rotational axis parallel to the vehicle width direction, and rotates by receiving the rotational force of the propeller shaft 2 via the ring gear 111. The first friction clutch 12A is disposed between the center shaft 112 and the rear wheel axle shaft 207L, and the second friction clutch 12B is disposed between the center shaft 112 and the rear wheel axle shaft 207R. Has been.

  In the four-wheel drive vehicle 200 configured as described above, transmission of the driving force from the engine 202 to the propeller shaft 2 in the two-wheel drive state is interrupted by the driving force interrupting device 3 and from the rear wheels 205L and 205R to the propeller shaft 2. Since the transmission of the rotational force is interrupted by the driving force transmission device 1, the rotation of the propeller shaft 2 is stopped even when the four-wheel drive vehicle 200 is traveling. Thereby, the stirring resistance of the lubricating oil in the front wheel side gear mechanism 44 and the rear wheel side gear mechanism 11 is reduced, and the fuel efficiency is improved.

  When the four-wheel drive vehicle 200 is switched from the two-wheel drive state to the four-wheel drive state, the rotational force of the rear wheels 205L and 205R is transmitted to the propeller shaft 2 via the driving force transmission device 1, and the propeller shaft 2 is rotated. Then, after the rotation synchronization of the meshing clutch 30 is completed, the driving force interrupting device 3 enters an operating state (a state where torque can be transmitted). Thereby, the four-wheel drive vehicle 200 will be in a four-wheel drive state.

  FIG. 3 is a cross-sectional view showing a specific example of the structure of the driving force transmission device 1. FIG. 4 is a cross-sectional view of the main part showing the configuration of the first friction clutch 12A and its periphery.

  As shown in FIG. 3, the driving force transmission device 1 includes the above-described gear mechanism 11, first and second friction clutches 12 </ b> A and 12 </ b> B, and a housing 13. The pinion gear 110 of the gear mechanism 11 is connected to the propeller shaft 2 by the intermediate shaft 20. The driving force transmission device 1 also includes a pair of left and right clutch housings 120 that respectively accommodate the first and second friction clutches 12A and 12B, and a pair of left and right inner shafts that are coaxially supported with the clutch housing 120 and are rotatably supported. The shaft 121 includes a pair of left and right connecting shafts 160 for connecting the clutch housing 120 and the rear wheel axle shafts 207L and 207R so as not to be relatively rotatable.

  The housing 13 includes a center housing member 130 that accommodates the pinion gear 110, the ring gear 111, and the center shaft 112 of the gear mechanism 11, and side housing members 131L and 131R that respectively accommodate the first and second friction clutches 12A and 12B. Prepare. The center housing member 130 is disposed between the side housing member 131L disposed on the left side in the vehicle width direction and the side housing member 131R disposed on the right side. The center housing member 130 and the side housing members 131L and 131R are fixed to each other by bolting. The housing 13 contains a lubricating oil (not shown) that lubricates the meshing of the gear in the gear mechanism 11 and the frictional sliding in the first and second friction clutches 12A and 12B.

  The center housing member 130 includes a first holding portion 130a that rotatably holds the pinion gear 110 of the gear mechanism 11 via the tapered roller bearings 113A and 113B, and the center shaft 112 of the gear mechanism 11 via the tapered roller bearing 113C. A second holding portion 130b that holds the pair of left and right inner shafts 121, a third holding portion 130c that holds the pair of left and right inner shafts 121 rotatably via a ball bearing 127A, and a piston 122 that will be described later are movably accommodated. A cylinder chamber 130d. The cylinder chambers 130d are formed at both ends of the center housing member 130 in the vehicle width direction and open toward the side housing members 131L and 131R.

  The center shaft 112 integrally includes a cylindrical cylindrical portion 112a extending along the rotation axis O and a flange portion 112b formed to protrude radially outward at an end portion of the cylindrical portion 112a. The ring gear 111 is formed with a plurality of meshing teeth 111 a that mesh with the gear portion 110 a of the pinion gear 110. Further, the ring gear 111 is fixed to the flange portion 112 b of the center shaft 112 by bolts 114.

  Each of the first and second friction clutches 12 </ b> A and 12 </ b> B is axially moved with respect to the inner shaft 121 and a plurality of outer clutch plates 124 that are axially movable relative to the clutch housing 120 and are not relatively rotatable. It has a plurality of inner clutch plates 125 that engage with each other in a non-rotatable manner. The plurality of outer clutch plates 124 and the plurality of inner clutch plates 125 are alternately arranged in a direction parallel to the rotation axis O of the center shaft 112 and are pressed by the piston 122. That is, the first and second friction clutches 12 </ b> A and 12 </ b> B receive a pressing force from the piston 122 and generate a frictional force between the plurality of outer clutch plates 124 and the plurality of inner clutch plates 125. The outer clutch plate 124 and the inner clutch plate 125 are one aspect of the friction member of the present invention.

  The piston 122 receives the hydraulic pressure of the hydraulic oil supplied from the hydraulic circuit 5 in the cylinder chamber 130 d of the center housing member 130 and presses the plurality of outer clutch plates 124 and the plurality of inner clutch plates 125. The cylinder chamber 130d functions as a hydraulic chamber that causes the hydraulic pressure of the hydraulic oil to act on the piston 122. The center housing member 130 is provided with a supply flow path 130e for guiding the hydraulic oil supplied from the hydraulic circuit 5 to the cylinder chamber 130d. Seal members 126A and 126B are disposed on the outer peripheral surface and the inner peripheral surface of the piston 122, respectively.

  The first and second friction clutches 12 </ b> A and 12 </ b> B receive the moving force of the piston 122 that receives the pressure of the hydraulic oil via the needle roller bearing 128 </ b> A and the pressing member 123, and the plurality of outer clutch plates 124 and the plurality of inner clutches. When the clutch plate 125 is brought into frictional contact, a rotational force is transmitted between the inner shaft 121 and the clutch housing 120. That is, the first and second friction clutches 12 </ b> A and 12 </ b> B receive a pressing force from the pressing member 123 and generate a frictional force between the plurality of outer clutch plates 124 and the plurality of inner clutch plates 125. As a result, the driving force of the engine 202 is transmitted to the rear wheels 205L and 205R via the first and second friction clutches 12A and 12B.

  On the other hand, in the first and second friction clutches 12A and 12B, when the piston 122 does not receive the pressure of the hydraulic oil, the plurality of outer clutch plates 124 and the plurality of inner clutch plates 125 are relatively rotatable. As a result, the first and second friction clutches 12A and 12B can block driving force transmission from the engine 202 to the rear wheels 205L and 205R.

  As shown in FIG. 4, the plurality of outer clutch plates 124 have spline protrusions 124 a on their outer peripheral parts, and these spline protrusions 124 a are engaged with straight spline fitting parts 120 a formed on the inner peripheral surface of the clutch housing 120. Match. The plurality of inner clutch plates 125 have spline protrusions 125 a on their inner peripheral portions, and these spline protrusions 125 a are engaged with straight spline fitting portions 121 a formed on the outer peripheral surface of the inner shaft 121.

  The pressing member 123 is formed of an annular plate member, and has a spline protrusion 123a that engages with the straight spline fitting portion 120a of the clutch housing 120 on the outer peripheral portion. Further, the pressing member 123 engages the spline protrusion 123a with the straight spline fitting portion 120a, is connected to the clutch housing 120 so as to be axially movable and relatively non-rotatable, and the piston 122 is provided with a needle roller bearing 128A. Are facing each other.

  Further, the clutch housing 120 is formed with a spline fitting portion 120b that is spline fitted to a spline fitting portion 160a formed on the outer peripheral surface of the connecting shaft 160. Thereby, the clutch housing 120 is connected to the connecting shaft 160 so as not to be relatively rotatable. The clutch housing 120 is rotatably supported by the side housing members 131L and 131R via needle roller bearings 128B.

  The inner shaft 121 has a columnar shaft portion 121b and a cylindrical portion 121c that accommodates one end portion of the connecting shaft 160, and the tip end portion of the shaft portion 121b is connected to the center shaft 112 so as not to be relatively rotatable by spline fitting. Has been. A needle roller bearing 128 </ b> C is disposed between the inner peripheral surface of the cylindrical portion 121 c and the outer peripheral surface of the connecting shaft 160. A ball bearing 127B and a seal member 129 are disposed between the inner surface of the opening at the end in the vehicle width direction of the side housing members 131L and 131R and the outer peripheral surface of the connecting shaft 160.

(Configuration and control method of hydraulic circuit)
FIG. 5 is a configuration diagram schematically illustrating a configuration example of the hydraulic circuit 5 together with the control unit 10 that controls the hydraulic circuit 5. The hydraulic circuit 5 includes a hydraulic pump 51 and an electric motor 52 that drives the hydraulic pump 51 as a hydraulic source 50. The control unit 10 controls the electric motor 52 to adjust the discharge pressure of the hydraulic pump 51. The electric motor 52 and the hydraulic pump 51 are connected by a shaft 521. The shaft 521 rotates integrally with the rotor of the electric motor 52. A reduction gear that reduces the rotation of the rotor at a predetermined reduction ratio may be provided between the shaft 521 and the rotor of the electric motor 52.

  The electric motor 52 is provided with an encoder 522 for detecting the angular position of the rotor with respect to the stator. The electric motor 52 is a DC brushless motor, for example, but a brushed DC motor may be used as the electric motor 52. The encoder 522 outputs a plurality of pulse signals while the rotor of the electric motor 52 makes one rotation.

  The hydraulic pump 51 is known per se and discharges hydraulic oil pumped up from the reservoir 510 with a discharge pressure corresponding to the rotation speed (rotational speed) of the electric motor 52. The discharge pressure of the hydraulic pump 51 increases in proportion to the rotation speed of the electric motor 52 as the rotation speed of the electric motor 52 increases. Further, the discharge pressure of the hydraulic pump increases as the temperature of the hydraulic oil is lower and the viscosity of the hydraulic oil is higher when the rotation speed of the electric motor 52 is constant. As the hydraulic pump 51, specifically, an external gear pump, an internal gear pump, or a vane pump can be used. The control unit 10 stores characteristic information indicating the relationship between the rotational speed of the electric motor 52 and the temperature of the hydraulic oil, and the discharge pressure of the hydraulic pump 51.

  The hydraulic circuit 5 includes first and second pressure control valves 531 and 532. The first pressure control valve 531 is disposed in the oil passage from the hydraulic pump 51 to the first friction clutch 12A, and adjusts the hydraulic pressure of the hydraulic oil supplied to the cylinder chamber 130d of the first friction clutch 12A. The second pressure control valve 532 is disposed in the oil path from the hydraulic pump 51 to the second friction clutch 12B, and adjusts the hydraulic pressure of the hydraulic oil supplied to the cylinder chamber 130d of the second friction clutch 12B.

  The first and second pressure control valves 531 and 532 are part of the hydraulic oil when the pressure of the hydraulic oil discharged from the hydraulic pump 51 is higher than the set pressure corresponding to the current supplied from the control unit 10. The hydraulic oil pressure is reduced to the set pressure and output. The control unit 10 controls the electric motor 52 so that the discharge pressure of the hydraulic pump 51 is slightly higher than the hydraulic oil pressure to be supplied to each of the cylinder chambers 130d corresponding to the first and second friction clutches 12A and 12B. Control. Further, the control unit 10 controls the first and second pressures so that the hydraulic oil whose discharge pressure of the hydraulic pump 51 is reduced is supplied to the cylinder chambers 130d corresponding to the first and second friction clutches 12A and 12B. Control valves 531 and 532 are controlled.

  The control unit 10 includes a target torque calculating unit 100 that calculates a target value of transmission torque (driving force) to be transmitted from the inner shaft 121 to the clutch housing 120 by the second friction clutches 12A and 12B, and a target torque calculating unit 100. Target discharge pressure calculation means 101 for calculating the target value of the discharge pressure of the hydraulic pump 51 based on the calculated target value of the transmission torque, and the target value calculated by the target discharge pressure calculation means 101 for the discharge pressure of the hydraulic pump 51 Feedback control means 102 that performs feedback control of the electric motor 52 so as to approach the gain, gain adjustment means 103 that adjusts the gain used in feedback control by the feedback control means 102, and a target of the transmission torque calculated by the target torque calculation means 100 Value and hydraulic oil temperature Hydraulic oil that estimates the temperature of the hydraulic oil based on the ratio of the feedforward control means 104 that calculates the feedforward control amount of the electric motor 52 and the current (motor current) supplied to the electric motor 52 and the rotational speed of the electric motor 52. Temperature estimation means 105.

  The target torque calculation means 100 includes a detection value of the wheel speed sensor 21 that detects the rotational speeds of the front wheels 204L and 204R and the rear wheels 205L and 205R, and an accelerator opening sensor that detects the amount of depression of the accelerator pedal by the driver. Based on the detected value of 22, the target value of the transmission torque to be transmitted by the first and second friction clutches 12A and 12B is calculated. The control unit 10 can acquire the detection value of the wheel speed sensor 21 and the detection value of the accelerator opening sensor 22 through an in-vehicle communication network such as CAN (Controller Area Network).

  The target discharge pressure calculation means 101 takes into account the hydraulic oil temperature estimated by the hydraulic oil temperature estimation means 105 based on the target value of the transmission torque set by the target torque calculation means 100, and the discharge pressure of the hydraulic pump 51. Set the target value.

  The feedback control means 102 uses a correction value based on the deviation between the target value and the actual value of the discharge pressure of the hydraulic pump 51 so that the discharge pressure of the hydraulic pump 51 becomes the target value set by the target discharge pressure calculation means 101. The electric motor 52 is feedback-controlled. In the present embodiment, the electric motor 52 is feedback-controlled so that the rotation speed of the electric motor 52 becomes a value corresponding to the target value of the discharge pressure set by the target discharge pressure calculating means 101. Specifically, the voltage applied to the electric motor 52 is adjusted by feedback control. As described above, since the discharge pressure of the hydraulic pump 51 is proportional to the rotation speed of the electric motor 52, the deviation between the target value and the actual value of the discharge pressure of the hydraulic pump 51 is the same as the target value of the rotation speed of the electric motor 52. It can be obtained by the difference from the actual rotational speed.

  The gain adjusting unit 103 is an aspect of the “correction amount adjusting unit” of the present invention, and changes the correction amount by the feedback control unit 102 by adjusting the gain according to the temperature of the hydraulic oil. Here, the correction amount refers to the absolute value (size) of the correction value. The gain adjustment means 103 changes the correction amount so that the correction amount of the feedback control becomes smaller as the temperature of the hydraulic oil becomes higher, in other words, as the viscosity of the hydraulic oil becomes lower. Specifically, the gain used in feedback control is lowered as the temperature of the hydraulic oil increases and the viscosity of the hydraulic oil decreases.

  In the present embodiment, the discharge pressure of the hydraulic pump 51 is obtained based on the number of revolutions of the electric motor 52, but a hydraulic sensor that detects the discharge pressure of the hydraulic pump 51 is provided, and the detected value of this hydraulic sensor is the target discharge. The electric motor 52 may be feedback-controlled so that the target value of the discharge pressure of the hydraulic pump 51 set by the pressure calculation means 101 is obtained. In this case, the deviation between the target value and the actual value of the discharge pressure of the hydraulic pump 51 can be obtained directly.

  The feedforward control means 104 calculates a voltage to be applied to the electric motor 52 as a feedforward control amount. This voltage is applied to the electric motor 52 by PWM modulating the voltage (12V) of a storage battery (battery) mounted on the four-wheel drive vehicle 200, and the effective value in a predetermined period depends on the voltage to be applied to the electric motor 52. Fluctuates depending on the duty ratio. Table 1 partially illustrates the relationship between the target value of the transmission torque calculated by the target torque calculation unit 100 and the temperature of the hydraulic oil, and the voltage (V) calculated by the feedforward control unit 104 in a tabular form. .

  The hydraulic oil temperature estimating means 105 estimates the temperature of the hydraulic oil by utilizing the fact that the ratio between the motor current supplied to the electric motor 52 and the rotation speed of the electric motor 52 varies depending on the temperature of the hydraulic oil. The control unit 10 can refer to the output signal of the current sensor 23 that measures the motor current supplied to the electric motor 52. The current sensor 23 measures and outputs a potential difference between both ends of a shunt resistor disposed in a current supply path to the electric motor 52, for example.

  FIG. 6 is a graph showing an example of the relationship between the temperature (oil temperature) of the hydraulic oil and the viscosity. When the viscosity of the hydraulic oil is 0 ° C. or higher, the viscosity gradually decreases as the temperature rises, and the fluid tends to flow. When the hydraulic oil is below 0 ° C., the viscosity rapidly increases and the fluidity decreases. When the hydraulic oil has a high viscosity, the rotational resistance of the hydraulic pump 51 increases, so that the rotational speed of the electric motor 52 is reduced even when a constant motor current is supplied to the electric motor 52. On the other hand, when the viscosity of the hydraulic oil is low, the rotational resistance of the hydraulic pump 51 decreases and the rotational speed of the electric motor 52 increases.

  Therefore, for example, if the relationship between the value obtained by dividing the current value of the motor current supplied to the electric motor 52 by the rotation speed of the electric motor 52 and the temperature of the hydraulic oil is stored in the control unit 10 in advance, the electric motor 52 is stored. It is possible to estimate the temperature of the hydraulic oil based on the motor current supplied to the motor and the rotational speed of the electric motor 52. In the present embodiment, the control unit 10 stores the relationship information between the value obtained by dividing the current value of the motor current obtained by experiments in advance by the number of revolutions and the temperature of the hydraulic oil.

  FIG. 7 shows that the torque transmitted by the first and second friction clutches 12A and 12B changes from the minimum value (two-wheel drive state) to the maximum value at high temperature (80 ° C.) and low temperature (−20 ° C.). It is a graph which shows an example of the relationship between the torque of the electric motor 52 in the case of doing, and rotation speed. In FIG. 7, “◯” indicates the operating point of the electric motor 52 when the transmission torque is the minimum value, and “●” indicates the operating point of the electric motor 52 when the transmission torque is the maximum value.

  As shown in FIG. 7, when the hydraulic oil is at a high temperature, it is necessary to operate the electric motor 52 at a higher rotation and a higher torque than at a low temperature. The target discharge pressure calculation means 101 sets a target value for the discharge pressure of the hydraulic pump 51 in consideration of this characteristic.

  FIG. 8 is a graph showing relationship information indicating a relationship between a value obtained by dividing the current value of the motor current supplied to the electric motor 52 by the rotation speed (ratio between the current value of the motor current and the rotation speed) and the temperature of the hydraulic oil. It has become. This relation information is obtained in advance by experiments and stored in the hydraulic oil temperature estimation means 105. The hydraulic oil temperature estimation means 105 estimates the hydraulic oil temperature with reference to this relationship information. In the graph shown in FIG. 8, the horizontal axis indicates the temperature of the hydraulic oil (oil temperature), and the vertical axis indicates a value obtained by dividing the current value of the electric motor 52 by the number of rotations.

  Hereinafter, the value obtained by dividing the current value of the motor current supplied to the electric motor 52 by the number of revolutions is referred to as “operating oil estimated temperature coefficient”, and the relationship information indicating the relationship between the estimated operating oil temperature coefficient and the temperature of the operating oil. It is called “hydraulic oil temperature related information”.

  As described above, when the temperature of the hydraulic oil is high, the viscosity of the hydraulic oil decreases and the rotational resistance of the hydraulic pump decreases, so that the rotational speed increases even if the motor current supplied to the electric motor 52 is the same. As a result, the estimated hydraulic oil temperature coefficient is reduced. On the other hand, if the temperature of the hydraulic oil is low, the viscosity of the hydraulic oil increases and the rotational resistance of the hydraulic pump increases, so the rotational speed decreases even if the motor current supplied to the electric motor 52 is the same. The estimated temperature coefficient increases. Therefore, it is possible to estimate the temperature of the hydraulic oil based on the hydraulic oil estimated temperature coefficient.

  In the experiment for obtaining the characteristics shown in FIG. 8, a predetermined motor current is supplied to the electric motor 52, and the temperature of the electric motor 52, the temperature of the hydraulic pump 51, and the temperature of the hydraulic oil are constant. Is performed by measuring the rotation speed of the electric motor 52 and the temperature of the hydraulic oil. Further, this measurement is performed at a plurality of (for example, five or more) measurement points where the current value of the motor current is changed.

  Next, the control method of the electric motor 52 of the driving force transmission device 1 performed by the control unit 10 will be described in more detail with reference to FIG. FIG. 9 is a control block diagram illustrating a configuration example of a control system of the electric motor 52.

  The detection values of the wheel speed sensor 21 and the accelerator opening sensor 22 are input to a target transmission torque calculator 60 realized by the target torque calculator 100. The target transmission torque calculation unit 60 increases the torque as the front and rear wheel rotation speed difference, which is the difference between the rotation speed of the front wheels 204L and 204R and the rotation speed of the rear wheels 205L and 205R, is larger. A target value T of the transmission torque is calculated so as to be transmitted by the first and second friction clutches 12A and 12B.

  The target discharge pressure calculation unit 61 sets a target value of the discharge pressure of the hydraulic pump 51 based on the target value T of the transmission torque calculated by the target torque calculation unit 60 and the estimated temperature of the hydraulic oil. At this time, the target discharge pressure calculation unit 61 refers to the characteristic information 61 a indicating the relationship between the rotation speed of the electric motor 52 and the temperature of the hydraulic oil and the discharge pressure of the hydraulic pump 51. The function of the target discharge pressure calculation unit 61 is realized by the target discharge pressure calculation means 101. In the present embodiment, the discharge pressure of the hydraulic pump 51 is higher than the hydraulic pressure of the hydraulic oil to be supplied to the cylinder chambers 130d corresponding to the first and second friction clutches 12A and 12B. Set the target value of the discharge pressure so that it is slightly higher.

  The target rotational speed calculation unit 62 calculates a target value R of the rotational speed of the electric motor 52 according to the target value of the discharge pressure of the hydraulic pump 51 calculated by the target discharge pressure calculation unit 61. The deviation calculation unit 63 calculates the rotation speed of the electric motor 52 based on the pulse signal output from the encoder 522, and calculates a deviation ε that is a difference from the target value R of the rotation speed of the electric motor 52. As described above, since the discharge pressure of the hydraulic pump 51 and the rotation speed of the electric motor 52 are in a proportional relationship, the deviation ε represents the deviation between the target value and the actual value of the discharge pressure of the hydraulic pump 51.

  The feedback control unit 64 performs feedback control of the electric motor 52 based on the deviation ε calculated by the deviation calculation unit 63. More specifically, the voltage applied to the electric motor 52 is increased or decreased so that the actual rotation speed of the electric motor 52 approaches the target value R of the rotation speed of the electric motor 52 set by the target rotation speed calculation unit 62. The electric motor 52 is feedback-controlled. The functions of the target rotational speed calculation unit 62, the deviation calculation unit 63, and the feedback control unit 64 are realized by the feedback control unit 102.

  In the present embodiment, PID (Proportional Integral Derivative) control is performed as this feedback control. PID control is a kind of feedback control, and controls a control target so that the actual value approaches the target value by the three elements of the deviation between the target value and the actual value, and the integral value and the differential value of the deviation. is there. In other words, proportional control (Proportional-control) that performs control based on the deviation between the target value and the actual value, integral control (Integral-control) that performs control based on the integral value of the deviation, and the differential value of the deviation Is a control that simultaneously performs differential control (Derivative-control) that performs control based on the above.

  The gain adjusting unit 65 is realized by the gain adjusting unit 103, and based on the hydraulic oil temperature (estimated temperature) estimated by the hydraulic oil temperature estimating unit 66 realized by the hydraulic oil temperature estimating unit 105, the feedback control unit 64. The gain used for PID control in is adjusted. This gain includes a proportional gain for proportional control, an integral gain for integral control, and a differential gain for differential control. The gain adjustment unit 65 decreases the proportional gain, the integral gain, and the differential gain as the temperature of the hydraulic oil increases.

  FIG. 10 is a graph showing an example of the relationship between the temperature of the hydraulic oil and the gain used for feedback control in the feedback control unit 63. In this graph, the gain (proportional gain, integral gain, differential gain) when the temperature of the hydraulic oil is 0 ° C. is 1 (reference value), and the change of the gain with respect to the temperature of the hydraulic oil is shown. FIG. 10 shows an example in which the gain changes in proportion to the temperature of the hydraulic oil. However, the present invention is not limited to this. For example, the gain change amount with respect to the hydraulic oil temperature change amount increases as the temperature decreases. The gain may be changed. The gain adjustment unit 65 stores information indicating the relationship between the temperature of the hydraulic oil and the gain shown in FIG. 10, and adjusts each gain with reference to the stored information. Further, in the present embodiment, all of the proportional gain, integral gain, and differential gain are adjusted according to the temperature of the hydraulic oil, but not limited thereto, some of the proportional gain, integral gain, and differential gain. (For example, only the differential gain, or only the proportional gain and the differential gain) may be adjusted.

  The hydraulic oil temperature estimation unit 66 calculates the rotation speed of the electric motor 52 based on the output signal of the encoder 522 and calculates the current value of the motor current supplied to the electric motor 52 based on the output signal of the current sensor 23. The temperature of the hydraulic oil is estimated based on the ratio between the calculated current value and the rotation speed of the electric motor 52.

  The feedforward control unit 67 is realized by the feedforward control unit 104 and is based on the target value T of the transmission torque calculated by the target torque calculation unit 60 and the temperature of the hydraulic oil estimated by the hydraulic oil temperature estimation unit 66. For example, the voltage to be applied to the electric motor 52 is calculated with reference to Table 1 above. A voltage obtained by adding the correction amount calculated by the feedback control unit 63 to the calculation result of the feedforward control unit 67 is applied to the electric motor 52. The correction amount calculated by the feedback control unit 63 increases as the deviation ε increases and as each gain increases.

  Further, the control unit 10 controls the first and second pressure control valves 531 and 532 based on the target value T of the transmission torque calculated by the target torque calculation unit 60. As described above, the target discharge pressure calculation unit 61 makes the discharge pressure of the hydraulic pump 51 higher than the hydraulic oil pressure to be supplied to the cylinder chambers 130d corresponding to the first and second friction clutches 12A and 12B. Since the target value R of the rotational speed of the electric motor 52 is calculated, the first and second pressure control valves 531 and 532 reduce the discharge pressure of the hydraulic pump 51 and output it to the cylinder chamber 130d side. As described above, hydraulic oil having a pressure corresponding to the target value T of the transmission torque is supplied to the cylinder chambers 130d corresponding to the first and second friction clutches 12A and 12B.

  According to the present embodiment described above, the feedback control gain changes according to the temperature of the hydraulic oil. That is, when the temperature of the hydraulic oil is low and the viscosity is high, the feedback control correction amount is large. Thereby, even if the rotational resistance of the hydraulic pump 51 is large, the rotational speed of the electric motor 52 can be quickly brought close to the target value. On the other hand, when the temperature of the hydraulic oil is high and the viscosity is low, the correction amount of the feedback control is small, so that the rotation speed of the electric motor 52 is suppressed from being over-controlled. As described above, in the present embodiment, even if the temperature of the hydraulic oil changes, the discharge pressure of the hydraulic oil from the hydraulic pump can be quickly brought close to the target pressure.

  Further, according to the present embodiment, since the temperature of the hydraulic oil can be obtained by estimation, a temperature sensor for detecting the temperature of the hydraulic oil becomes unnecessary, and the cost of the apparatus can be reduced.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the temperature of the electric motor 52 is estimated and the estimated temperature of the electric motor 52 is taken into account in order to further improve the control accuracy with respect to the driving force transmission device 1 according to the first embodiment. To estimate the temperature of the hydraulic oil. Since other configurations are the same as those in the first embodiment, differences from the first embodiment will be mainly described.

  FIG. 11 is a configuration diagram schematically showing the control unit 10 according to the present embodiment together with a configuration example of the hydraulic circuit 5. FIG. 12 is a control block diagram illustrating a configuration example of a control system of the electric motor 52 according to the present embodiment. As shown in FIG. 11, the control unit 10 according to the present embodiment can acquire the measurement result of the outside air temperature by the outside air temperature sensor 24.

  When the temperature of the electric motor 52 rises, the electrical resistance of the winding of the exciting coil increases and the magnetic force of the permanent magnet of the electric motor 52 decreases. When the permanent magnet of the electric motor 52 is a ferrite magnet, its magnetic force decreases by about 0.2% with a temperature increase of 1 ° C. Therefore, for example, when the temperature of the electric motor 52 (the temperature of the permanent magnet) changes from −20 ° C. to 80 ° C., even if a constant current is supplied to the winding of the electric motor 52, the output torque of the electric motor 52 Decreases by about 20%.

  The hydraulic oil temperature related information described with reference to FIG. 8 in the first embodiment is the steady state in which the temperature of the electric motor 52, the temperature of the hydraulic pump 51, and the temperature of the hydraulic oil are constant as described above. Since it is set based on the experimental results of measuring the rotational speed of the electric motor 52 and the temperature of the hydraulic oil in the state, when the electric motor 52 is controlled in this steady state, the motor current-output depending on the temperature of the electric motor 52 The change in torque characteristics is taken into account, and the temperature of the hydraulic oil is accurately estimated. However, when the motor current supplied to the electric motor 52 is greatly increased in a short time, for example, when the vehicle running state is switched from the two-wheel drive state to the four-wheel drive state, the temperature rise rate of the hydraulic oil The temperature of the electric motor 52 rises at a large temperature rise rate, and the output torque falls. This is because the amount of heat generated by the electric motor 52 increases in proportion to the square of the motor current, and the heat capacity of the electric motor 52 is smaller than the heat capacity of the hydraulic oil. As a result, the temperature of the hydraulic oil cannot be estimated accurately, and the control accuracy may be reduced.

  Therefore, in the present embodiment, the control unit 10 includes the electric motor temperature estimation unit 106 that estimates the temperature of the electric motor 52 based on the current value of the motor current, and the hydraulic oil temperature estimation unit 105 includes the electric motor temperature estimation unit. Considering the temperature of the electric motor 52 estimated by the means 106, the temperature of the hydraulic oil is estimated.

  In the control block diagram of FIG. 12, the motor temperature estimating unit 68 is realized by the electric motor temperature estimating means 106, and the motor current of the electric motor 52 measured by the current sensor 23 and the outside air temperature measured by the outside air temperature sensor 24. Based on the above, the temperature of the electric motor 52 is estimated. The temperature of the electric motor 52 estimated by the motor temperature estimation unit 68 is referred to by the hydraulic oil temperature estimation unit 66. A specific example of a calculation method for estimating the temperature of the electric motor 52 will be described later.

  In the present embodiment, the hydraulic oil temperature estimation means 105 (hydraulic oil temperature estimation unit 66) estimates the hydraulic oil temperature at a predetermined calculation cycle, and the previous estimated value of the hydraulic oil temperature and the electric motor temperature estimation means. When the difference from the temperature of the electric motor 52 estimated at 106 is equal to or greater than a predetermined value, a correction coefficient is obtained according to the estimated temperature of the electric motor 52, and the motor current obtained by applying this correction coefficient is calculated. Based on the ratio between the current value and the rotation speed (the estimated hydraulic oil temperature coefficient), the temperature of the hydraulic oil is estimated with reference to the hydraulic oil temperature related information.

  FIG. 13 is a flowchart illustrating a specific example of processing performed by the hydraulic oil temperature estimation unit 105 in one calculation cycle. This calculation cycle is, for example, 1 second.

  The hydraulic oil temperature estimation means 105 acquires the current value of the motor current of the electric motor 52 measured by the current sensor 23 and the rotation speed of the electric motor 52 detected by the encoder 522 (steps S1 and S2). Next, the hydraulic oil temperature estimation means 105 has a value obtained by subtracting the estimation result of the hydraulic oil temperature in the previous calculation cycle from the temperature of the electric motor 52 estimated by the electric motor temperature estimation means 106 (for example, 10). It is determined whether it is less than (C) (step S3).

  As a result of this determination, if the difference between the estimation result of the hydraulic oil temperature and the estimated temperature of the electric motor 52 is less than a predetermined value (step S3: Yes), the hydraulic oil temperature estimation means 105 acquires the electric motor temperature acquired in step S1. A value obtained by dividing the current value of the motor current of the motor 52 by the rotation speed of the electric motor 52 acquired in step S2 is set as a hydraulic oil estimated temperature coefficient (step S4), and the temperature of the hydraulic oil is determined by referring to the hydraulic oil temperature related information. Estimate (step S7).

  On the other hand, if the difference between the estimation result of the hydraulic oil temperature and the estimated temperature of the electric motor 52 is greater than or equal to a predetermined value as a result of the determination (step S3: No), the hydraulic oil temperature estimation means 105 is the electric motor temperature estimation means. A correction coefficient is obtained based on the temperature of the electric motor 52 estimated by 106 (step S5), and a product obtained by multiplying the correction coefficient by the current value of the motor current obtained in step S1 is divided by the number of rotations of the electric motor 52. The value is set as the estimated hydraulic oil temperature coefficient (step S6), and the hydraulic oil temperature is estimated with reference to the hydraulic oil temperature related information (step S7). A method for calculating the correction coefficient will be described later.

  In the above description, the hydraulic oil temperature estimation unit 105 determines that the difference between the estimated hydraulic oil temperature in the previous calculation cycle and the temperature of the electric motor 52 estimated by the electric motor temperature estimation unit 106 in step S3 is a predetermined value. However, the present invention is not limited to this. For example, the average value of the estimated temperature of hydraulic oil calculated in a plurality of calculation cycles including the calculation cycle before the previous time and the electric motor temperature estimation means It may be determined whether the difference between the temperature of the electric motor 52 estimated at 106 is less than a predetermined value.

  Next, a specific example of the estimation calculation of the temperature of the electric motor 52 by the electric motor temperature estimation means 106 (motor temperature estimation unit 68) will be described. The electric motor temperature estimation unit 106 estimates the temperature of the electric motor 52 by calculation at the same calculation cycle as the calculation cycle in which the hydraulic oil temperature estimation unit 105 estimates the temperature of the hydraulic oil, for example.

Assuming that the estimated result of the temperature of the electric motor 52 in the previous calculation cycle is Tpre and the amount of change in the temperature of the electric motor 52 from the previous calculation time is ΔTpre, the estimated temperature Tcur of the electric motor 52 in the current calculation cycle Is obtained by the following formula (1).

  Here, the amount of change in temperature of the electric motor 52 can be obtained as a value obtained by subtracting the temperature decrease due to heat dissipation from the temperature increase due to the motor current and further multiplying by the inverse of the heat capacity of the electric motor 52. This temperature increase can be obtained according to a product obtained by multiplying the square of the motor current supplied to the electric motor 52 by the resistance value of the winding of the electric motor 52. Further, the temperature drop can be obtained by a product obtained by subtracting the outside air temperature from Tpre, which is the estimated result of the temperature of the electric motor 52 in the previous calculation cycle, and multiplying by a predetermined heat transfer coefficient. This heat transfer coefficient is a heat transfer coefficient when the heat of the electric motor 52 is dissipated to the outside air, and can be obtained by experiments, for example.

Accordingly, when the temperature rise of the electric motor 52 is Q, the heat capacity of the electric motor 52 is C, the heat transfer coefficient is λ, and the outside air temperature is Tamb, the estimated temperature Tcur of the electric motor 52 is obtained by the following equation (2). It is done.

  Next, a specific example of a correction coefficient calculation method when the difference between the estimated temperature of the hydraulic oil and the estimated temperature of the electric motor 52 is a predetermined value or more will be described with reference to FIG.

  FIG. 14 is a graph showing the relationship between the temperature of the electric motor 52 and the output torque of the electric motor 52 when the motor current is constant. In this graph, the horizontal axis indicates the temperature of the electric motor 52, and the vertical axis indicates the output torque of the electric motor 52. Here, an example in which the output torque of the electric motor 52 changes in proportion to the temperature of the electric motor 52 is shown.

  The electric motor temperature estimation means 106 stores characteristic information indicating the relationship between the temperature of the electric motor 52 and the output torque, for example, for the current values of a plurality of motor currents, and among these, the motor measured by the current sensor 23 is stored. The correction coefficient is calculated with reference to the characteristic information closest to the measured current value.

  14 is the estimated temperature of the hydraulic oil calculated by the hydraulic oil temperature estimating means 105, and Tem is the estimated temperature of the electric motor 52 calculated by the electric motor temperature estimating means 106. As this Tem, the estimated temperature Tcur of the electric motor 52 by the electric motor temperature estimating means 106 in the most recent calculation cycle is used. The correction coefficient is calculated as a value (Tom / Tof) obtained by dividing the value (Tom) on the vertical axis corresponding to Tem by the value (Tof) on the vertical axis corresponding to Tef. The estimated hydraulic oil temperature coefficient is obtained as a quotient obtained by dividing the product of the current value of the motor current supplied to the electric motor 52 by the correction coefficient (= Tom / Tof) by the rotation speed of the electric motor 52.

  According to this embodiment, in addition to the effects described in the first embodiment, the temperature of the electric motor 52 is estimated, and the temperature of the hydraulic oil is estimated by taking the estimated temperature of the electric motor 52 into account. The temperature of the hydraulic oil can be estimated more accurately, and the control accuracy is improved.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, as in the second embodiment, the temperature of the hydraulic oil is estimated by taking into account the estimated temperature of the electric motor 52. The specific method is the same as that of the second embodiment. Is different. Since other configurations are the same as those in the second embodiment, differences from the second embodiment will be mainly described.

  In the first and second embodiments, the case where the hydraulic oil temperature estimation unit 105 stores one piece of hydraulic oil temperature relationship information indicating the relationship between the hydraulic oil estimated temperature coefficient and the hydraulic oil temperature has been described. In the present embodiment, the hydraulic oil temperature estimation means 105 has a plurality of hydraulic oil temperatures corresponding to the difference between the estimated temperature of the hydraulic oil and the estimated temperature of the electric motor 52 (hereinafter, this difference is referred to as “estimated temperature difference”). The related information is stored, and the temperature of the hydraulic oil is estimated with reference to one hydraulic oil temperature related information selected from the plurality of hydraulic oil temperature related information. Here, the estimated temperature difference is a value obtained by subtracting the estimated temperature of the hydraulic oil from the estimated temperature of the electric motor 52. Moreover, the electric motor temperature estimation means 106 estimates the temperature of the electric motor 52 by calculation at a predetermined calculation cycle, as in the second embodiment.

  FIG. 15 is a graph illustrating an example of a plurality of pieces of hydraulic oil temperature related information stored by the hydraulic oil temperature estimation unit 105 according to the present embodiment. In FIG. 15, the solid line indicates hydraulic oil temperature-related information when the estimated temperature difference is 0 ° C., the broken line indicates hydraulic oil temperature-related information when the estimated temperature difference is 10 ° C., and the alternate long and short dash line indicates the estimated temperature difference of 20 The operating oil temperature related information in the case of ° C., and the two-dot chain line show the operating oil temperature related information in the case where the estimated temperature difference is 30 ° C., respectively. The plurality of pieces of hydraulic oil temperature related information can be obtained by experiments performed by adjusting the temperature difference between the hydraulic oil and the electric motor 52.

  In the graph of FIG. 15, the hydraulic oil temperature related information indicated by the solid line is the same as that described with reference to FIG. 8 in the first embodiment, and the hydraulic oil temperature and the electric motor 52 temperature are the same. The reference relationship information indicates the relationship between the estimated hydraulic oil temperature coefficient and the hydraulic oil temperature. The hydraulic oil temperature estimating means 105 estimates the hydraulic oil temperature at a predetermined calculation cycle, and the difference between the previous estimated value of the hydraulic oil temperature and the temperature of the electric motor 52 estimated by the electric motor temperature estimating means 106. Is less than the predetermined value, the temperature of the hydraulic oil is estimated with reference to the standard relationship information. Further, the hydraulic oil temperature estimation means 105 determines the reference when the difference between the previous estimated value of the hydraulic oil temperature and the temperature of the electric motor 52 estimated by the electric motor temperature estimation means 106 is a predetermined value or more. One hydraulic oil temperature relation information corresponding to the difference is selected from a plurality of hydraulic oil temperature relation information other than the relation information, and the temperature of the hydraulic oil is estimated with reference to the selected hydraulic oil temperature relation information.

  Further, in the present embodiment, the hydraulic oil temperature estimation means 105 compares the temperature of the electric motor 52 estimated by the electric motor temperature estimation means 106 using the estimated value of the previous calculation cycle of the hydraulic oil temperature. Assumed to be performed. However, the present invention is not limited to this. For example, the average value of the estimated temperature of hydraulic oil calculated in a plurality of calculation cycles including the calculation cycle before the previous time and the temperature of the electric motor 52 estimated by the electric motor temperature estimating means 106 The estimated temperature difference may be obtained by comparison.

  The hydraulic oil temperature estimation means 105 selects one hydraulic oil temperature related information with the closest calculated estimated temperature difference among the plurality of hydraulic oil temperature related information. For example, when the estimated temperature difference is 15 ° C. or more and less than 25 ° C., the hydraulic oil temperature related information indicated by the alternate long and short dash line in FIG. 15 is selected. Note that the hydraulic oil temperature estimation unit 105 may store a plurality of hydraulic oil temperature related information in a table format, for example. In this case, the temperature of the hydraulic oil is estimated by listing the selected hydraulic oil temperature related information.

  Also in this embodiment, the same effect as that of the second embodiment can be obtained.

(Appendix)
The clutch device and the control method of the clutch device according to the present invention have been described above based on the embodiment. However, the present invention is not limited to this embodiment, and can be appropriately modified without departing from the scope of the present invention. It is possible to implement.

  Further, the configuration of the driving force transmission system 201 in the four-wheel drive vehicle 200 is not limited to that illustrated in FIG. 1 and the like, and various configurations can be adopted. Furthermore, the clutch device according to the present invention is not limited to the four-wheel drive vehicle 200 but can be applied to various devices.

DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device (clutch apparatus), 10 ... Control part, 100 ... Target torque calculation means, 101 ... Target discharge pressure calculation means, 102 ... Feedback control means, 103 ... Gain adjustment means, 104 ... Feed forward control means, DESCRIPTION OF SYMBOLS 105 ... Hydraulic oil temperature estimation means, 106 ... Electric motor temperature estimation means, 11 ... Gear mechanism, 110 ... Pinion gear, 110a ... Gear part, 111 ... Ring gear, 111a ... Meshing tooth, 112 ... Center shaft, 112a ... Cylindrical part, 112b ... Flange portion, 113A to 113C ... Tapered roller bearing, 114 ... Bolt, 120 ... Clutch housing, 120a ... Straight spline fitting portion, 120b ... Spline fitting portion, 121 ... Inner shaft, 121a ... Straight spline fitting portion, 121b ... Shaft part, 121c ... Cylindrical part, 1 2 ... Piston, 123 ... Pressing member, 123a ... Spline protrusion, 124 ... Outer clutch plate (friction member), 124a ... Spline protrusion, 125 ... Inner clutch plate (friction member), 125a ... Spline protrusion, 126A, 126B ... Seal member DESCRIPTION OF SYMBOLS 127A, 127B ... Ball bearing, 128A-128C ... Needle roller bearing, 129 ... Seal member, 12A ... First friction clutch, 12B ... Second friction clutch, 13 ... Housing, 130 ... Center housing member, 130a- 130c ... first to third holding portions, 130d ... cylinder chamber (hydraulic chamber), 130e ... supply channel, 131L, 131R ... side housing member, 160 ... connection shaft, 160a ... spline fitting portion, 2 ... propeller Shaft, 20 ... Intermediate shaft, 200 ... Four-wheel drive vehicle DESCRIPTION OF SYMBOLS 201 ... Driving force transmission system, 202 ... Engine, 203 ... Transmission, 204L, 204R ... Front wheel, 205L, 205R ... Rear wheel, 206L, 206R, 207L, 207R ... Axle shaft, 21 ... Wheel speed sensor, 22 ... Accelerator opening Sensor, 23 ... Current sensor, 24 ... Outside air temperature sensor, 3 ... Driving force interrupting device, 30 ... Clutch, 300 ... Actuator, 31-33 ... First to third rotating members, 310, 320 ... Recess, 311, 321 331 ... Spline teeth, 332 ... Annular groove, 34 ... Electric motor, 341 ... Output shaft, 35 ... Reduction mechanism, 351 ... Pinion gear, 352 ... Reduction gear, 352a ... Large diameter gear part, 352b ... Small diameter gear part, 36 ... Movement Mechanism, 361 ... Linear motion shaft, 361a ... Rack teeth, 362 ... Shift fork, 4 ... Front differential 40, front differential case, 41 ... pinion shaft, 42 ... pinion gear, 43 ... side gear, 44 ... gear mechanism, 441 ... drive pinion, 442 ... ring gear, 5 ... hydraulic circuit, 50 ... hydraulic source, 51 ... hydraulic pump, 510 ... reservoir, 52 ... electric motor, 521 ... shaft, 522 ... encoder, 531 ... first pressure control valve, 532 ... second pressure control valve, 60 ... target torque calculator, 61 ... target discharge pressure calculator, 61a ... Characteristic information, 62 ... Target rotational speed calculation unit, 63 ... Deviation calculation unit, 64 ... Feedback control unit, 65 ... Gain adjustment unit, 66 ... Hydraulic oil temperature estimation unit, 67 ... Feed forward control unit, 68 ... Motor temperature estimation Part, O ... axis of rotation

Claims (8)

A friction clutch that receives a pressing force and generates a friction force between the friction members;
A piston that receives hydraulic pressure and presses the friction clutch;
A hydraulic chamber for applying the hydraulic pressure to the piston;
A hydraulic pump for supplying hydraulic oil to the hydraulic chamber;
An electric motor for driving the hydraulic pump;
A controller that controls the electric motor to adjust the discharge pressure of the hydraulic pump;
The controller is
Feedback control means for feedback-controlling the electric motor with a correction value based on a deviation between a target value and an actual value of the discharge pressure of the hydraulic pump so that the discharge pressure of the hydraulic pump becomes a target pressure;
Hydraulic oil temperature estimation means for estimating the temperature of the hydraulic oil based on the ratio between the current value of the motor current supplied to the electric motor and the rotational speed of the electric motor;
Correction amount adjustment means for changing a correction amount by the feedback control according to the estimated temperature of the hydraulic oil,
Clutch device. The control unit includes an electric motor temperature estimation unit that estimates a temperature of the electric motor based on a current value of the motor current,
The hydraulic oil temperature estimating means estimates the temperature of the hydraulic oil in consideration of the estimated temperature of the electric motor;
The clutch device according to claim 1. The hydraulic oil temperature estimation means stores relationship information indicating a relationship between the ratio and the temperature of the hydraulic oil, and estimates the temperature of the hydraulic oil with reference to the relationship information.
The clutch device according to claim 2. The hydraulic oil temperature estimating means estimates the temperature of the hydraulic oil at a predetermined cycle, and the estimated value of the hydraulic oil temperature before the previous time and the temperature of the electric motor estimated by the electric motor temperature estimating means. When the difference is equal to or greater than a predetermined value, a correction coefficient is obtained according to the estimated temperature of the electric motor, and the operation is performed with reference to the relation information based on the ratio obtained by applying the correction coefficient. Estimate the temperature of the oil,
The clutch device according to claim 3. The hydraulic oil temperature estimation means stores a plurality of relationship information indicating the relationship between the ratio and the temperature of the hydraulic oil according to an estimated temperature difference between the estimated temperature of the hydraulic oil and the estimated temperature of the electric motor, and Estimating the temperature of the hydraulic oil with reference to one of the relationship information selected from a plurality of the relationship information;
The clutch device according to claim 2. One of the plurality of the relationship information is reference relationship information indicating a relationship between the ratio and the temperature of the hydraulic oil when the temperature of the hydraulic oil and the temperature of the electric motor are the same.
The hydraulic oil temperature estimating means estimates the temperature of the hydraulic oil at a predetermined cycle, and the estimated value of the hydraulic oil temperature before the previous time and the temperature of the electric motor estimated by the electric motor temperature estimating means. When the difference is less than a predetermined value, the temperature of the hydraulic oil is estimated with reference to the reference relationship information, and when the difference is equal to or greater than the predetermined value, the difference is determined from a plurality of the relationship information. Selecting the one relationship information;
The clutch device according to claim 5. The controller calculates a feedforward control amount of the electric motor based on a target value of torque to be transmitted by the friction clutch and a temperature of the hydraulic oil;
The clutch device according to any one of claims 1 to 6. A friction clutch that receives a pressing force and generates a friction force between the friction members;
A piston that receives hydraulic pressure and presses the friction clutch;
A hydraulic chamber for applying the hydraulic pressure to the piston;
A hydraulic pump for supplying hydraulic oil to the hydraulic chamber;
A control method of a clutch device comprising an electric motor for driving the hydraulic pump,
The hydraulic oil temperature is estimated based on the ratio of the current value of the motor current supplied to the electric motor and the rotational speed of the electric motor, and the hydraulic pump discharge pressure becomes a target pressure. The electric motor is feedback controlled by a correction value based on a deviation between a target value and an actual value of the pump discharge pressure, and a correction amount by the feedback control is changed according to the estimated temperature of the hydraulic oil.
Control method of clutch device.

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