Four-wheel drive vehicle and control device for a four-wheel drive vehicle
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- JTEKT CORP
- Filing Date
- 2017-10-09
- Publication Date
- 2026-07-23
AI Technical Summary
Existing four-wheel drive vehicles face inaccuracies in controlling the friction clutch due to shifts in sensor and amplifier properties over time or temperature changes, leading to errors in current output, which affects the precise transmission of driving force to auxiliary wheels.
A four-wheel drive vehicle system with a dog clutch and friction clutch configuration, utilizing a control device that includes a current output circuit, detector, target current value calculator, and controller to enhance the accuracy of current output for precise control of the friction clutch, incorporating a zero-point adjustment mechanism to compensate for temperature fluctuations.
The system improves the accuracy of current control to the friction clutch, ensuring precise transmission of driving force to auxiliary wheels, enhancing fuel efficiency and stability, particularly during mode transitions.
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Abstract
Description
BACKGROUND OF THE INVENTION 1. Field of the invention
[0001] The present invention relates to a four-wheel drive vehicle comprising main drive wheels, to which a driving force from a drive source is constantly transmitted, and auxiliary drive wheels, to which the driving force is transmitted in a separable manner. The present invention also relates to a control device for the four-wheel drive vehicle. 2. Description of the related prior art
[0002] A four-wheel drive vehicle is known to date, comprising main drive wheels to which a driving force from a drive source is constantly transmitted, a drive shaft configured to transmit the driving force in a front-and-rear direction of the vehicle, auxiliary drive wheels to which the driving force from the drive source is transmitted via the drive shaft, a dog clutch and a friction clutch provided such that the drive shaft is inserted between them in a driving force transmission path to the auxiliary drive wheels, and a control device configured to control the dog clutch and the friction clutch (see, for example, Japanese patent publication no. JP 2013-164099 A and Japanese patent publication JP 2009-269605 A).
[0003] When the four-wheel drive vehicle, constructed as described above, operates in a two-wheel drive mode, where power is transmitted only to the main drive wheels, rotation of the drive shaft can be stopped by interrupting the transmission of power through both the dog clutch and the friction clutch. Consequently, the driving resistance caused by the rotation of the drive shaft can be reduced, thereby improving fuel efficiency. When the four-wheel drive vehicle operates in a four-wheel drive mode, where power is transmitted to both the main drive wheels and the auxiliary drive wheels, the dog clutch is engaged, and the friction clutch is electrically controlled to regulate the power transmitted to the auxiliary drive wheels.
[0004] In the four-wheel drive vehicle described in JP 2013-164099 A, a connection / disconnect unit corresponds to 415 on the front wheel side in Fig. 1 of the claw coupling, a drive shaft or cardan shaft 419 corresponds to the drive shaft and a connecting / disconnecting unit 31 On the rear wheel side, this corresponds to the friction clutch. In the four-wheel drive vehicle described in JP 2009-269605 A, this corresponds to a switching device. 3 on the front wheel side in Fig. 3 or the like of the claw coupling, an intermediate shaft 11 corresponds to the drive shaft and a half-shaft coupling 4 This corresponds to the friction clutch.
[0005] When the four-wheel drive vehicle, constructed as described above, is operating in four-wheel drive mode, the control device determines the drive force to be transmitted to the auxiliary drive wheels, for example, based on the difference between the rotational speeds of the front and rear wheels and the amount of pressure applied to an accelerator pedal or gas pedal, and outputs a current to the friction clutch corresponding to the drive force. The current must be highly accurate, and consequently, the control device detects the actual current output to the friction clutch and regulates it such that the current value corresponds to the drive force to be transmitted to the auxiliary drive wheels.For example, if a sensor unit configured to detect a current and an amplifier circuit configured to amplify a signal output by the sensor unit exhibit a mismatch or offset in their characteristics due to changes over time or temperature, an error will occur in the current output from the control device to the friction clutch, even when the control is executed. As a result, the friction clutch cannot be precisely controlled. SUMMARY OF THE INVENTION
[0006] It is an object of the present invention to provide a four-wheel drive vehicle comprising a jaw clutch and a friction clutch, provided such that a drive shaft is inserted between them in a drive power transmission path to auxiliary drive wheels, and a control device configured to control the jaw clutch and the friction clutch, in which the accuracy of a current to be output by the control device to control the friction clutch can be increased.
[0007] A four-wheel drive vehicle according to an embodiment of the present invention comprises: Main drive wheels to which a driving force from a drive source is constantly transmitted; a drive shaft configured to transmit the drive force in a front-and-rear direction of the vehicle; Auxiliary drive wheels, to which the driving force of the drive source is transmitted via the drive shaft; a first drive power transmission device and a second drive power transmission device arranged such that the drive shaft is inserted between the first drive power transmission device and the second drive power transmission device in a drive power transmission path to the auxiliary drive wheels; and a control device configured to control the first drive force transmission device and the second drive force transmission device.
[0008] The first drive force transmission device comprises a jaw coupling configured to transmit the drive force by engagement between projections and recesses.
[0009] The second drive force transmission device comprises an outer rotary element and an inner rotary element which are held to be rotatable coaxially with respect to each other, an outer coupling plate which is configured to rotate together with the outer rotary element, an inner coupling plate which is configured to rotate together with the inner rotary element, and a pressing mechanism which is configured to press the outer coupling plate and the inner coupling plate in an axial direction by a pressing force in accordance with a control current supplied by the control device.
[0010] The control device comprises a current output circuit configured to output the control current to the pressing mechanism, a current sensing device configured to output a sensing signal corresponding to a magnitude of the control current actually output by the current output circuit, a setpoint current value calculation device configured to calculate a setpoint current value which is a setpoint of the control current to be supplied to the pressing mechanism, and a current control device configured to control the current output circuit such that the control current having the current value calculated by the setpoint current value calculation device based on a result of a sensing performed by the current sensing device is output to the pressing mechanism.When the four-wheel drive vehicle is in a two-wheel drive operating mode, in which the transmission of the driving force performed by both the first and second driving force transmission devices is interrupted, the current control device is configured to perform a zero-point adjustment to store information that the sensing signal output by the current sensing device indicates a zero point for the control current to be output by the current output circuit.
[0011] In accordance with the four-wheel drive vehicle as described above, it is possible to increase the accuracy of the current to be output by the control device to control the friction clutch. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The aforementioned and further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawing, in which the same reference numerals are used to represent identical elements. The drawing shows:
[0013] Fig. 1 a structural diagram illustrating the schematic structure of a four-wheel drive vehicle according to a first embodiment of the present invention;
[0014] Fig. 2A a sectional view illustrating an example of the construction of a first drive power transmission device;
[0015] Fig. 2B an exemplary representation which schematically illustrates an engagement contact section of the first drive force transmission device in the example of the construction of the first drive force transmission device;
[0016] Fig. 3 a sectional view illustrating a specific example of the construction of a second drive force transmission device;
[0017] Fig. 4 a main section view illustrating the construction of a first friction clutch and associated peripherals;
[0018] Fig. 5 a structural diagram that schematically illustrates an example of the setup of a hydraulic circuit and a control device;
[0019] Fig. 6. A block diagram illustrating an example of the structure of a control system implemented by a control unit, together with an example of the structure of a current output circuit;
[0020] Fig. 7 a flowchart illustrating a processing procedure to be carried out by a power control device as a control unit;
[0021] Fig. 8 a structural diagram that schematically illustrates an example of the setup of a hydraulic circuit and a control device according to a second embodiment;
[0022] Fig. 9 a structural diagram illustrating the schematic construction of a four-wheel drive vehicle according to a third embodiment of the present invention; and
[0023] Fig. 10 a sectional view illustrating an example of the construction of a coupling device of the second drive power transmission device fitted in the four-wheel drive vehicle. DETAILED DESCRIPTION OF THE EXAMPLES OF EXECUTION
[0024] A first embodiment of the present invention is described with reference to Fig. 1 to Fig. 7 described.
[0025] Fig. Figure 1 shows a structural diagram illustrating the schematic structure of a four-wheel drive vehicle according to the first embodiment of the present invention.
[0026] A four-wheel drive vehicle 1 includes a power machine 11 , which serves as a power source configured to generate a driving force for a drive, a transmission 12 , which is configured, the rotational speed that is generated by the power engine 11 is issued to vary, front wheels 13R and 13L , which serve as a pair of right and left main drive wheels, rear wheels 14R and 14L , which serve as a pair of right and left auxiliary drive wheels, a drive power transmission system 10 , which is capable of generating the driving force of the power machine 11 , which is obtained through the speed variation provided by the transmission 12 is carried out, to the front wheels13R and 13L and the rear wheels 14R and 14L to transmit, and a control device 2 In this embodiment, the suffixes “R” and “L” of the reference numerals are used to represent “right” and “left” with respect to a forward direction of travel of the vehicle.
[0027] The four-wheel drive vehicle 1 is between a four-wheel drive operating mode, in which the driving force of the power machine 11 to the front wheels 13R and 13L as well as the rear wheels 14R and 14L is transmitted, and a two-wheel drive operating mode in which the driving force of the power machine 11 only to the front wheels 13R and 13L The transmission is switchable. The driving force of the power machine 11 becomes constant towards the front wheels 13R and 13L transferred and goes to the rear wheels 14R and 14Ltransmitted in response to driving conditions or driver switching operations.
[0028] This exemplary embodiment describes a case in which an internal combustion engine is used as the drive source, although the present invention is not limited to this. The drive source can be formed by a combination of an internal combustion engine and a high-performance electric motor, such as an internal permanent magnet synchronous motor (IPM motor), or by a high-performance electric motor alone.
[0029] The drive power transmission system 10 forms a drive force transmission path that is connected to the gearbox 12 of the four-wheel drive vehicle 1 to each of the front wheels 13R and 13L and the rear wheels 14R and 14L That's enough. The drive power transmission system 10 includes a front differential 3, drive axles 15R and 15L , which are between the front differential 3 and the front wheels 13R and 13L are arranged, a first drive force transmission device 4 , adjacent to the front differential 3 is arranged, a drive shaft or cardan shaft 5 , which serves as a drive shaft, configured to transmit the driving force of the power machine 11 to transmit in a front-and-rear direction of the vehicle, a second drive force transmission device 6 , which are behind the drive shaft 5 is arranged in the front and rear direction of the vehicle, and drive axles 16R and 16L , which are between the second drive force transmission device 6 and the rear wheels 14R and 14L are arranged.
[0030] The control device 2controls the first drive power transmission device 4 and the second drive force transmission device 6 The first drive force transmission device 4 and the second drive force transmission device 6 are arranged in such a way that the drive shaft 5 in between in the drive power transmission path to the rear wheels 14R and 14L is inserted. The driving force of the power machine 11 becomes the rear wheels 14R and 14L via the drive shaft 5 transferred. This setup controls the four-wheel drive vehicle. 1 in two-wheel drive mode, the control device 2 the first drive force transmission device 4 and the second drive force transmission device 6 , in order to interrupt the transmission of the driving force. Consequently, the drive shaft can 5to be brought into a non-rotating state. This eliminates the driving resistance that would otherwise result from the rotation of the drive shaft. 5 is caused, thereby improving fuel efficiency. The two-wheel drive operating mode, in which the transmission of the driving force, which is caused by both the first driving force transmission device 4 as well as the second drive force transmission device 6 The operation is interrupted, and is referred to below as a separate operating mode of the drive power transmission system. 10 designated.
[0031] The front differential 3 includes a front differential housing 30 , a pinion shaft or gear shaft 31 , which is configured to fit together with the front differential housing 30 to turn a pair of pinion gears 32 , which are rotatable via the pinion shaft 31to be held, and a pair of axle shaft wheels 33 , which are connected to the pinion gears 32 are engaged, with the associated gear shafts positioned orthogonally to each other. The front differential 3 is between the gearbox 12 and the first drive force transmission device 4 arranged. The drive axles 15R and 15L are each connected to the axle shaft wheels 33 coupled.
[0032] The drive shaft or cardan shaft 5 is formed by a multitude of wave elements connected to each other by a multitude of universal joints. 51 are coupled, which have articulated cross joints. A drive pinion. 52 is at the end of the drive shaft 5 provided on the front of the vehicle, with a coupling section 53 at the end of the drive shaft 5It is located on the rear of the vehicle. A coupling section 53 is connected to a coupling element (described below). 600 the second drive force transmission device 6 coupled in relation to the coupling element 600 not to be rotatable. The center of the drive shaft 5 in an associated longitudinal direction, a central bearing 50 held in such a way as to be rotatable in relation to the vehicle body.
[0033] Fig. Figure 2A shows a sectional view illustrating an example of the construction of the first drive power transmission device. 4 illustrated. Fig. Figure 2B shows an exemplary representation that schematically depicts an engagement contact section of the first drive force transmission device. 4 in the example of the construction of the first drive force transmission device 4 illustrated. Fig. 2A illustrates an upper half section of the first drive force transmission device. 4 with respect to a rotational axis O1 of the front differential housing 30 .
[0034] The first drive force transmission device 4 includes a claw coupling 40 , which is configured to transmit the driving force through an engagement between projections and recesses. More precisely, the first driving force transmission device comprises 4 a claw coupling 40 , which are formed by the first to third rotating elements 41 until 43 is formed, which are configured to be coaxial with the front differential housing 30 to turn, an actuating device 400 , which is configured, the claw coupling 40 to operate, and a toothed ring 44 , which engages with the pinion gear 52 the drive shaft 5is, where the associated gear shafts are positioned orthogonally to each other.
[0035] The operating device 400 includes an electric motor 45 , a speed reduction mechanism 46 , which is configured to control the rotational speed of an output shaft 451 of the electric motor 45 to reduce, and a movement mechanism 47 , which is configured, the third rotating element 43 the claw coupling 40 in a corresponding axial direction by a torque of the electric motor 45 to move, which is obtained through the speed reduction achieved by the speed reduction mechanism 46 is executed. The electric motor 45 is powered by a current supplied by the control device 2 is supplied.
[0036] The first rotating element 41 is at the axial end of the front differential housing 30It is fixed and rotates together with the front differential housing. 30 The second rotating element 42 is coaxial with respect to the first rotating element 41 rotatable. The third rotating element 43 is on an outer peripheral side of the second rotating element 42 provided to have a cylindrical shape, being axial with respect to the second rotating element 42 is movable.
[0037] The first rotating element 41 has a ring-shaped form, so that the drive axle 15R on the right front wheel side by an inner peripheral side of the first rotating element 41 is inserted. The first rotating element 41 has a large number of wedge-shaped teeth. 411 recesses, which are formed on an associated outer peripheral surface to extend parallel to the axis of rotation O1. 410 are each between a pair of wedge teeth 411, which are adjacent to each other in a circumferential direction, from the multitude of wedge teeth 411 trained. The second rotating element 42 has a tubular shape, so that the drive axle 15R through the second rotating element 42 is inserted. The gear ring 44 is at one axial end of the second rotating element 42 fixed. The second rotating element 42 has a large number of wedge-shaped teeth. 421 recesses, which are formed on an associated outer peripheral surface to extend parallel to the axis of rotation O1. 420 are each between a pair of wedge teeth 421 , which are adjacent to each other in the circumferential direction, from the multitude of wedge teeth 421 trained.
[0038] A multitude of wedge teeth 431 is on the inner peripheral surface of the third rotating element 43 formed. The wedge teeth 431can use the wedge teeth 411 of the first rotating element 41 and the wedge teeth 421 of the second rotating element 42 to be engaged. In this embodiment, the wedge teeth engage. 431 of the third rotating element 43 into the recesses 420 of the second rotating element 42 one, wherein the third rotating element 43 with regard to the second rotating element 42 is axially movable while the intervention state is maintained.
[0039] When the third rotating element 43 in the direction of the first rotating element 41 through the movement mechanism 47 As the teeth are moved, they engage. 431 of the third rotating element 43 , which serve as the projections into the depressions 410 of the first rotating element 41 one, whereby consequently the third rotating element 43 with the first rotating element 41is coupled in order to be in relation to the first rotating element 41 not to be rotatable. Thus, the first rotating element 41 and the second rotating element 42 together via the third rotating element 43 coupled so as not to be rotatable relative to each other, thereby reaching a state in which the driving force of the power machine 11 from the first rotating element 41 to the second rotating element 42 is transferable. If the third rotating element 43 away from the first rotating element 41 When moved, the wedge teeth 431 of the third rotating element 43 from the depressions 410 of the first rotating element 41 disengaged, consequently disabling the first rotating element 41 and the second rotating element 42 are rotatable relative to each other. Thus, the transmission of the driving force from the first rotating element is 41to the second rotating element 42 interrupted.
[0040] The speed reduction mechanism 46 includes a pinion gear 461 , which is configured to align itself with the output wave 451 of the electric motor 45 to rotate, and a speed reduction gear 462 , which is a gear section with a large diameter 462a , which engages with the pinion gear 461 is, and a small diameter gear section 462b , which is configured to fit together with the large diameter gear section 462a to rotate, exhibits. The movement mechanism 47 includes a linear axis of movement 471 , the rack teeth 471a exhibits, which engages with the small-diameter gear section 462b of the speed reduction gear 462 are, and a shift fork 472 , which are located on the linear axis of motion 471is fixed. The third rotating element 43 has a ring-shaped groove 432 on, which is formed on the associated outer peripheral surface. The switching fork 472 is lubricated to fit into the ring-shaped groove 432 It fit.
[0041] If the wave of releases 451 of the electric motor 45 as it rotates, the rotational speed of the output shaft will be 451 through the speed reduction mechanism 46 reduced, whereby the linear axis of motion 471 moved parallel to the axis of rotation O1. Together with the movement of the linear axis of motion. 471 the third rotating element moves 43 between a coupled position in which the third rotating element 43 in engagement with the first rotating element 41 and the second rotating element 42 is, and a decoupled position in which the third rotating element 43 not engaging with the first rotating element41 is.
[0042] As it is in Fig. As illustrated in 1, the second drive force transmission device includes 6 a case 60 , which is held by the vehicle body, a gear mechanism or transmission mechanism 61 on the rear wheel side, to which the driving force is transferred from the drive shaft 5 The transmission occurs via the first and second friction clutches. 62R and 62L , which are configured to provide the driving force through the transmission mechanism 61 is transmitted, to regulate and the driving force to the drive axles 16R and 16L to be transmitted on the rear wheel side, and a hydraulic shifting system 70 , which is configured, each of the first and second friction clutches 62R and 62L to supply hydraulic pressure. The housing 60 houses the first and second friction clutches 62R and62L as well as the transmission mechanism 61 .
[0043] The gear mechanism 61 includes a pinion gear 610 and a gear ring 611 , which are in mesh with each other, with associated gear shafts being orthogonal to each other, and a central shaft 612 , which is configured to fit together with the gear ring 611 to rotate the center shaft 612 It has an associated axis of rotation that is parallel to a vehicle width direction and rotates by a rotational force from the drive shaft. 5 via the gear ring 611 is received. The first friction clutch 62R is between medium wave 612 and the drive axle 16R arranged on the rear wheel side, with the second friction clutch 62L between medium wave 612 and the drive axle 16L is located on the rear wheel side.
[0044] If the four-wheel drive vehicle 1 When the vehicle switches from two-wheel drive mode to four-wheel drive mode while driving, the control device initiates 2 the drive axle 5 , to rotate by using the rotational forces of the rear wheels 14R and 14L to the drive shaft 5 via the second drive force transmission device 6 are transmitted, thereby causing the rotation of the first rotating element. 41 the first drive force transmission device 4 with the rotation of the second rotating element 42 the first drive force transmission device 4 The synchronization process is completed. Once the rotational synchronization is finished, the actuating device is activated. 400 the first drive force transmission device 4 controlled in such a way that the third rotating element 43 in engagement with the first rotating element 41is. In this way, the four-wheel drive vehicle 1 switched to four-wheel drive mode.
[0045] Fig. Figure 3 shows a sectional view illustrating a specific example of the construction of the second drive force transmission device. 6 illustrated. Fig. Figure 4 is a main section view showing the construction of the first friction clutch. 62L and an associated periphery.
[0046] In the second drive force transmission device 6 is the pinion gear 610 the transmission mechanism 61 to the coupling section 53 the drive shaft 5 (see Fig. 1) through the coupling element 600 coupled, in order to relate to the coupling section 53 not to be rotatable. The second drive force transmission device 6 includes clutch drums 63 , inner waves64 , a pair of right and left coupling waves 65 , various warehouses 661 until 669 , Pistons 67 and press elements 68 The clutch drums 63 serve as a pair of right and left outer rotary elements that form the first and second friction clutches. 62R and 62L each house. The inner waves 64 serve as a pair of right and left inner rotating elements, which are located on an inner side of the clutch drums. 63 are arranged in each case. The coupling shafts 65 The clutch drums each couple 63 and the drive axles 16R and 16L on the rear wheel side together, so that the clutch drums 63 and the drive axles 16R and 16L are not rotatable relative to each other. The clutch drum 63 and the inner wave 64are held in such a way that they can be rotated coaxially in relation to each other.
[0047] The case 60 includes a central housing element 60C , the pinion gear 610 , the gear ring 611 and the medium wave 612 the transmission mechanism 61 houses, and side case elements 60R and 60L , which are the first and second friction clutches 62R and 62L each house. The central housing elements 60C is between the side housing element 60R , which is located on the right side in the direction of the vehicle's width, and the side housing element 60L , which is located on the left side in the direction of the vehicle's width. The center housing element 60C and the side case elements 60R and 60L are fixed to each other by a bolt fastening. The housing 60is equipped with a (not illustrated) lubricating oil for lubricating the engagement between gears of the transmission mechanism 61 and a frictional sliding of each of the first and second friction clutches 62R and 62L filled.
[0048] The center housing element 60C includes a first mounting section 601 , which is the pinion gear 610 the transmission mechanism 61 via the tapered roller bearings 661 and 662 Rotatable, holds a second mounting section 602 , which uses the medium wave 612 the transmission mechanism 61 about a pair of tapered roller bearings 663 and 664 Rotatable, it holds a third mounting section 603 , which is the pair of right and left inner waves 64 about the ball bearings 665 Each one is rotatable, and the cylinder chambers 604 , each part of the pistons 67accommodate, so that the pistons 67 The cylinder chambers are movable forwards and backwards on the inside. 604 are at both ends of the central housing element 60C designed in the vehicle width direction and are directed towards the side body elements 60R and 60L open. The coupling waves 65 are used in the side housing elements 60R and 60L through the ball bearings 666 held.
[0049] The medium wave 612 integrally exhibits a cylindrical section 612a , which extends along a rotational axis O2 of the medium shaft 612 extends, and a flange section 612b on, which at the end of the cylindrical section 612a is designed to protrude radially outwards. A variety of intervention teeth. 611a is on the gear ring 611 trained. The intervention teeth 611a engage in a gear section 610aof the pinion gear 610 one. The gear ring 611 is on the flange section 612b the medium wave 612 with bolts or screws 614 fixed.
[0050] Each of the first and second friction clutches 62R and 62L includes a variety of external coupling plates 621 , which is connected to the clutch drum 63 are engaged in relation to the clutch drum 63 axially movable but not rotatable, and a variety of internal coupling plates 622 , which interact with the inner wave 64 are in relation to the inner wave 64 to be axially movable but not rotatable. The outer coupling plates 621 and the inner coupling plates 622 are alternating in one direction parallel to the axis of rotation O2 of the medium shaft 612 arranged and are driven by the piston 67pressed. That is, each of the first and second friction clutches. 62R and 62L generates a frictional force between the outer coupling plates 621 and the inner coupling plates 622 , by applying a pressing force from the piston 67 is received.
[0051] The piston 67 presses the outer coupling plates 621 and the inner coupling plates 622 , by applying a hydraulic pressure to a hydraulic oil supplied by the hydraulic circuit 70 the cylinder chamber 604 is supplied, is received. The central housing element 60C is connected to a feeder flow path 605 for introducing the hydraulic oil that is supplied by the hydraulic circuit 70 is supplied into the cylinder chamber 604 Equipped with ring-shaped sealing elements. 671 and 672 are located on the outer peripheral surface and the inner peripheral surface of the piston 67each one arranged.
[0052] Each of the first and second friction clutches 62R and 62L transmits the rotational force between the inner shaft 64 and the clutch drum 63 such that the outer coupling plates 621 and the inner coupling plates 622 are brought into frictional contact with each other by means of the needle bearings 667 and the pressing element 68 the pressing force of the piston 67 , which receives the pressure of the hydraulic oil. Thus, the driving force of the power machine is 11 to the rear wheels 14R and 14L via the first and second friction clutches 62R and 62L Each one transferred. The pressing element 68 rotates together with the clutch drum 63 , where the needle bearing 667 between the piston 67 and the pressing element 68 is arranged.
[0053] In each of the first and second friction clutches 62R and 62L are the outer coupling plates 621 and the inner coupling plates 622 freely rotatable relative to each other when the piston 67 does not receive the pressure of the hydraulic oil. Therefore, the first and second friction clutches cannot... 62R and 62L the transmission of the driving force from the power machine 11 to the rear wheels 14R and 14L interrupt each time.
[0054] The clutch drum 63 integrally features a cylindrical section with a large diameter 631 , a cylindrical section with a small diameter 632 and a side wall section 633 between the cylindrical section with large diameter 631 and the small-diameter cylindrical section 632 up. As it is in Fig. As illustrated in section 4, the outer coupling plates 621 Wedge projections 621a on associated outer peripheral sections. The wedge-shaped projections 621a engage in straight wedge pass sections 631a one that is located on the inner peripheral surface of the large-diameter cylindrical section 631 the clutch drum 63 are designed. Thus, the outer coupling plates rotate. 621 together with the clutch drum 63 The needle thrust bearing 668 is between the side wall section 633 the clutch drum 63 and each of the side case elements 60R and 60L arranged.
[0055] The pressing element 68 is a plate element that has a circular ring shape and features wedge-shaped projections 68a on an associated outer peripheral section. The wedge-shaped projections 68a engage in straight wedge pass sections631a the clutch drum 63 one. Through the engagement between the wedge projections 68a and the straight wedge pass sections 631a is the pressing element 68 to the clutch drum 63 coupled, in relation to the clutch drum 63 axially movable but not rotatable.
[0056] Wedge-shaped sections 632a are located on the inner peripheral surface of the small-diameter cylindrical section 632 the clutch drum 63 trained. The wedge-shaped sections 632a are in a wedge fit with wedge-shaped pass sections 65a , which are located on the outer peripheral surface of the coupling wave 65 are trained. Thus, the clutch drum 63 to the coupling shaft 65 coupled, in relation to the coupling shaft 65 not to be rotatable.
[0057] The inner wave 64has a cylindrical section 641 and a columnar wave section 642 up. The cylindrical section 641 houses one end of the coupling wave 65 The distal end of the wave segment 642 is connected to the medium wave 612 coupled by a wedge fit, so that the inner shaft 64 with regard to the medium wave 612 is not rotatable. The needle bearing 669 is between the inner peripheral surface of the cylindrical section 641 and the outer peripheral surface of the coupling wave 65 arranged. A sealing element 69 is between the open inner surface of each of the side case elements 60R and 60L at the end in the vehicle width direction and the outer peripheral surface of the coupling shaft 65 arranged.
[0058] The inner coupling plates 622 show wedge-shaped projections 622aon associated inner peripheral sections. The wedge-shaped projections 622a engage in straight wedge pass sections 641a one that is located on the outer peripheral surface of the cylindrical section 641 the inner wave 64 are formed. Thus, the inner coupling plates rotate. 622 together with the inner wave 64 .
[0059] Fig. Figure 5 shows a structural diagram that schematically illustrates an example of the hydraulic circuit setup. 70 and the control device 2 Illustrated. The hydraulic circuit 70 includes a hydraulic pump 71 , which serves as a hydraulic pressure source, an electric motor 72 , which is configured, the hydraulic pump 71 to drive, and first and second solenoid valves 73 and 74 The hydraulic pump 71 and the electric motor 72are connected to each other by a coupling wave 721 coupled. The control device 2 leads the electric motor 72 a motor current, whereby the electric motor 72 the hydraulic pump 71 drives.
[0060] A speed reduction device can be installed between the coupling shaft 721 and the electric motor 72 The speed reduction device reduces the speed of the electric motor. 72 at a predetermined speed reduction ratio. The electric motor 72 For example, a brushless DC motor is used, but a brushed DC motor is considered the electric motor. 72 can be used.
[0061] The hydraulic pump 71 It is itself a well-known hydraulic pump, in which it uses hydraulic oil that comes from a reservoir. 710The pumping process uses an output pressure corresponding to the number of revolutions (speed) of the electric motor. 72 emits. An opening 711 is between one discharge side of the hydraulic pump 71 and the container 710 arranged. An external gear pump, an internal gear pump, or a vane pump can be considered a specific example of a hydraulic pump. 71 be used.
[0062] The first solenoid valve 73 is located in an oil path that is supplied by the hydraulic pump 71 to the cylinder chamber 604 of the side housing element 60L That's enough. The second solenoid valve 74 is located in an oil path that is supplied by the hydraulic pump 71 to the cylinder chamber 604 of the side housing element 60R That's enough. Each of the first and second solenoid valves 73 and 74is a pressure control valve that is configured to regulate the pressure of the hydraulic oil supplied by the hydraulic pump. 71 the cylinder chamber 604 to be supplied, to be regulated. More precisely, each of the first and second solenoid valves 73 and 74 An electromagnetic proportional pressure control valve. The pressure of the hydraulic oil supplied by the hydraulic circuit 70 to the cylinder chamber 604 The output changes according to a current supplied by the control device. 2 to each of the first and second solenoid valves 73 and 74 is supplied. Each of the first and second solenoid valves 73 and 74 includes an electromagnetic solenoid (not illustrated), with the current supplied by the control device 2is supplied to a coil of the electromagnetic solenoid, thereby moving a valve element. The term "control current" is used below to represent the current supplied by the control device. 2 supplied to increase the pressure of the hydraulic oil that enters the cylinder chamber 604 to supply, to regulate.
[0063] Each of the first and second solenoid valves 73 and 74 allows some of the hydraulic oil that comes from the hydraulic pump to escape. 71 is expelled to reduce the pressure of the hydraulic oil, and releases the pressure towards the cylinder chamber. 604 off. The pressure of the hydraulic oil supplied by each of the first and second solenoid valves 73 and 74 towards the cylinder chamber 604 The output changes proportionally, for example, to the control current. The control device 2 controls the electric motor 72such that the discharge pressure of the hydraulic pump 71 higher than the hydraulic pressure of the hydraulic oil that flows into each of the cylinder chambers 604 the side case elements 60R and 60L to be supplied.
[0064] The hydraulic pump 71 , the electric motor 72 , the first and second solenoid valves 73 and 74 and the pistons 67 form a pressing mechanism 7 , which is configured, the outer coupling plates 621 and the inner coupling plates 622 the first and second friction clutches 62R and 62L in the axial direction by pressing forces corresponding to the control currents supplied by the control device 2 to be fed, to be pressed. In this embodiment, the control device guides 2 the control currents to the first and second solenoid valves 73 and 74the press mechanism 7 to, thereby reducing the pressing forces applied to the first and second friction clutches 62R and 62L to be created, are regulated.
[0065] The control device 2 includes a power output circuit 20 and a control unit 200 The current output circuit 20 supplies the control current to the pressing mechanism 7 off. The control unit 200 includes a current monitoring device 21 , which is configured to output a detection signal corresponding to the magnitude of the control current actually supplied by the current output circuit 20 A target current value calculation device is output. 22 , which is configured to calculate a target current value, which is a target value of the control current supplied to the pressing mechanism 7 to be supplied, and a power control device 23, which is configured, the power output circuit 20 to control in such a way that the control current, which has the current value determined by the target current value calculation device 22 based on the result of a recording made by the electricity recording device 21 is executed, is calculated, on the pressing mechanism 7 is output. The target current value calculation device. 22 calculates the target current value of the control current based on measured values from a wheel speed sensor. 17 , which is configured to control the rotational speed of each of the front wheels 13R and 13L and the rear wheels 14R and 14L to detect, and from an acceleration device opening degree sensor 18 , which is configured to detect the depressor amount of an accelerator pedal being depressed by a driver.
[0066] Fig. Figure 6 shows a block diagram that illustrates an example of the structure of a control system. 8 This is illustrated by the control unit 200 is implemented, along with an example of the construction of the current output circuit. 20 The current output circuit 20 is able to supply the control currents to the first solenoid valve 73 and the second solenoid valve 74 to issue independently, and the power recording device 21 is able to measure current values (actual current values) of the control currents that are actually applied to the first solenoid valve 73 and the second solenoid valve 74 to be issued, to be recorded. Fig. Figure 6 illustrates only one circuit section of the current output circuit. 20 , which supplies the control current to the first solenoid valve 73 outputs. A circuit section for outputting and sensing the control current for the second solenoid valve. 74It has a similar structure.
[0067] The power output circuit 20 includes a connection device 190 , a first connection 201 , a second connection 202 , a freewheeling diode 203 and a switching element 204 The connecting device 190 is powered by a current from a DC power supply (battery) 19 supplied, which is located in the four-wheel drive vehicle 1 is appropriate. The first connection 201 and the second connection 202 are electrically connected to one end and the other end of a coil 730 of the electromagnetic solenoid of the first solenoid valve 73 connected. The free-running iodine 203 is between the first connection 201 and the second connection 202 connected. The switching element 204 For example, a transistor or a FET. Fig. Figure 6 illustrates a circuit example in which the FET is used as the switching element. 204 is used.
[0068] A shunt resistor 210 is between the connecting device 190 and the first connection 201 connected. The shunt resistor 210 detects a current that leads to the first solenoid valve 73 The current value of the current passing through the shunt resistor is displayed. 210 The current flowing is equal to the current value of the current (control current) flowing through the coil. 730 flows. When the switching element 204 When switched on, the current flows, which is supplied by the battery. 19 is supplied through the coil 730 via the connection device 190 and the shunt resistance 210 If the switching element 204 When the switch is off, a current temporarily flows through the freewheeling diode. 203due to the inductance of the coil 730 .
[0069] The functions of the target current value calculation device 22 and the power control device 23 the control unit 200 are implemented, for example, in such a way that a CPU of the control device 2 executes a program that is stored in a memory element. These functions can be implemented by hardware.
[0070] The control system 8 The control elements include an amplifier circuit. 80 and an electricity procurement unit 81 , which are measured by the current detection device 21 are implemented, a target transmission torque calculation unit 82 and a torque / current conversion unit 83 , which are calculated by the target current value calculation device 22 are implemented, as well as a control unit 84and a PWM output unit 85 , which is controlled by the current control device 23 are implemented.
[0071] The amplifier circuit 80 includes an operational amplifier 800 , an initial resistance 801 , which is between a negative (–) input terminal of the operational amplifier 800 and one end of the shunt resistor 210 connected, a second resistor 802 , which is between a positive (+) input terminal of the operational amplifier 800 and the other end of the shunt resistor 210 connected, a third resistor 803 , which is between an output terminal of the operational amplifier 800 and one end of the shunt resistor 210 is connected, and a fourth resistor 804 , which is between the other end of the shunt resistor 210and is connected to a ground or earth potential. The amplifier circuit 80 amplifies a potential difference caused by a voltage drop between the two ends of the shunt resistor 210 is generated, and outputs it.
[0072] The electricity procurement unit 81 samples an output voltage of the amplifier circuit 80 It then performs an analog-to-digital conversion to transform an analog signal into a digital signal. The current value acquisition unit 81 It outputs as a detection signal the signal obtained as a result of the A / D conversion and indicates the actual current value of the control current.
[0073] Data is collected by the wheel speed sensor 17 and the acceleration device opening degree sensor 18 into the target transmission torque calculation unit 82 Entered. The target transmission torque calculation unit.82 calculates drive forces (target transmission torques) that are sent to the rear wheels 14R and 14L to be transmitted, so that the driving forces increase when the speed difference between the front and rear wheels increases or when the amount of pressure applied to the accelerator pedal (accelerator pedal opening degree) increases. The speed difference between the front and rear wheels is the difference between the average speed of the front wheels. 13R and 13L and an average rotational speed of the rear wheels 14R and 14L If the four-wheel drive vehicle 1 When driving around a curve, the target transmission torques for the rear wheels are... 14R and 14L regulated in such a way that a greater driving force is directed to one of the rear wheels 14R and 14Lis transferred, which is located on one outer side during the curve, as to the other of the rear wheels 14R and 14L , which is positioned on an inside side during the curve. This allows the cornering maneuver of the four-wheel drive vehicle to be improved. 1 be stabilized.
[0074] If there is no need to direct the drive forces to the rear wheels 14R and 14L To transmit, the target transmission torque calculation unit is used. 82 the target transmission torques are reduced to zero, so that the drive force transmission system 10 The system switches to separate operating mode. At this time, the control device controls... 2 the first drive force transmission device 4 , in order to interrupt the transmission of the drive forces. The target transmission torques, which are calculated by the target transmission torque calculation unit 82The torque / current conversion unit will be calculated. 83 supplied.
[0075] The torque / current conversion unit 83 Based on the target transmission torques, it calculates a target current value for the control current that goes to the pressing mechanism. 7 The output is generated by referencing characteristic curve information that is stored in advance. This characteristic curve information is information that establishes a relationship between the control current, the press mechanism, and the operating current. 7 to be supplied (specifically to the first and second solenoid valves) 73 and 74 ), and the torques (driving forces) that are applied to the drive axles 16R and 16L through the first and second friction clutches 62R and 62L Specify which ones are to be transferred.
[0076] Based on a difference between the target current value, which is determined by the torque / current conversion unit 83 is calculated, and the actual current value of the control current supplied by the current value procurement unit 81 The control unit is output. 84 The control unit adjusts the system so that the actual current value approaches the target current value more closely. Specifically, the control unit calculates... 84 a relative duty cycle or duty ratio that indicates a proportion of a time during which the switching element is inactive 204 is switched on. The control unit 84It presents a PID controller as a specific example of control. PID control is a type of control system in which a control objective is managed in such a way that an actual value is closer to a setpoint, based on three factors: the deviation between the setpoint and the actual value, the integral value of the deviation, and the differential value of the deviation.
[0077] The PWM output unit 85 sends a gate signal to the switching element 204 off, so that the switching element 204 at the duty cycle that is switched on by the control unit 84 is calculated.
[0078] According to the control system described above, the drive forces are adjusted according to the target transmission torques, which are based on the measured values from the wheel speed sensor. 17and the acceleration device opening degree sensor 18 to be calculated, to the rear wheels 14R and 14L transmitted. By sending the control currents to the first solenoid valve 73 and the second solenoid valve 74 Can be issued independently, the cornering maneuver of the four-wheel drive vehicle can be 1 be stabilized, even if the four-wheel drive vehicle 1 driving on a road with low µ, such as a wet road.
[0079] Next, details of a processing operation carried out by the power control device will be described. 23 as the control unit 84 to be executed with reference to Fig. 7 described.
[0080] Fig. Figure 7 shows a flowchart illustrating a processing procedure performed by the power control device. 23 as the control unit 84to be executed. The power control device 23 This involves a series of processing steps that are in Fig. Figure 7 illustrates the operation at each predetermined control time duration (for example, 5 ms). At predetermined times based on timer values (a first timer value and a second timer value) from a first timer and a second timer, the current control device executes the following commands: 23 a zero-point adjustment or zero-point alignment for storing information indicates that the detection signal from the current detection device 21 The output indicates a zero point of the control current, which is determined by the current output circuit. 20 to be output. In the following description, an expression "Clear" means that the timer value is set to zero, and an expression "Increment" means that a value of 1 is added to the timer value.
[0081] The zero-point adjustment is performed to ensure the accuracy of the control current supplied by the control device. 2 to spend in order to replace each of the first and second friction clutches 62R and 62L to control, to increase, thereby increasing the driving force that goes to each of the rear wheels 14R and 14L The transmission process is controlled with high accuracy. More precisely, the current control device performs this function. 23 the zero point adjustment to detect fluctuations in the detection signal from the power value acquisition unit 81 to be issued, for example due to a temperature increase of the control device 2 (Temperature drift).
[0082] The temperature drift is caused, for example, by a change in the resistance of a shunt resistor. 210 or the first to fourth resistors 801 until 804or a change in the operational amplifier's properties 800 or the A / D converter of the power value procurement unit 81 This is caused by the temperature increase. The temperature drift causes an error in the detection signal from the current sensing device. 21 is output. Consequently, the current sensing device 21 For example, output a detection signal indicating that the control current is being output, even though the control current is not actually going to the pressing mechanism. 7 is output. Such an error causes an increase in the difference between the driving force actually delivered to each of the rear wheels. 14R and 14L The transmission torque is transmitted, and the target transmission torque is affected. As a result, there is a possibility that the desired driving performance cannot be achieved.
[0083] In the processing according to the flowchart that is in Fig. As illustrated in 7, the current control device determines 23 first, whether the drive power transmission system 10 in separate operating mode (step S1). The determination can be carried out, for example, on the basis of whether the target transmission torque, which is calculated by the target transmission torque calculation unit, 82 The calculation is zero.
[0084] If the drive power transmission system 10 If the device is not in separate operating mode (step S1: No), the current control device is deactivated. 23 the first timer value and the second timer value (step S2), whereby they then use the aforementioned control processing as the control unit 84 executes (step S3). Then the power control device terminates. 23 the processing within a control time period.
[0085] If the drive power transmission system 10In the separate operating mode (step S1: Yes), the current control device increases or increments 23 both the first timer value and the second timer value (step S4). Next, the current control device determines 23 , whether the first timer value equals a first threshold value (step S5). The first threshold value is, for example, a value corresponding to 100 ms (if the control duration is 5 ms, the value is 20 (= 100 / 5)). If the first timer value equals the first threshold value (step S5: Yes), the current control device executes 23 The zero point adjustment (step S6) is performed and the processing is completed within a control time period.
[0086] If the first timer value is not equal to the first threshold value (step S5: No), the current control device determines 23The system checks whether the second timer value equals a second threshold value (step S7). If the second timer value equals the second threshold value as a result of the determination (step S7: Yes), the current control device clears the signal. 23 The second timer value (step S8) is received, the zero-point adjustment is performed (step S6), and the processing is completed within a control time period. If the second timer value is not equal to the second threshold (step S7: No), the current control device terminates. 23 The processing takes place within a control time duration without executing the processing according to steps S8 and S6. The second threshold is, for example, a value corresponding to 5 seconds (if the control time duration is 5 ms, the value is 1,000 (= 5,000 / 5)).
[0087] Specifically, the zero-point adjustment in step S6 is a process for storing information that, in the separate operating mode, the value of the detection signal from the current detection device 21 The output indicates the zero point of the control current supplied by the current output circuit. 20 to be output. After processing, the power control device subtracts 23 the stored value of the value of the detection signal from the current detection device 21 is output, and executes the control processing in step S3.
[0088] In this embodiment, the zero-point adjustment is performed when a first predetermined time, specified by the first threshold, has elapsed since the drive power transmission system 10The system has switched to separate operating mode. If separate operating mode continues thereafter, the zero-point adjustment is performed repeatedly each time a second predetermined time, specified by the second threshold, has elapsed. The second predetermined time is longer than the first predetermined time.
[0089] In this embodiment, the processing described below, as well as the processing according to the flowchart shown in Fig. As illustrated in section 7, if a starter switch (for example, an ignition switch) is used to start the engine, then the following applies: 11 When switched on, the zero point adjustment is performed before the control current is supplied by the current output circuit. 20 to the pressing mechanism 7 This processing is carried out to determine the drive force that goes to each of the rear wheels. 14R and 14Lto transmit, to control with high accuracy, even if, for example, the starter switch is turned on in a state where the temperature of the control device 2 is high and the four-wheel drive vehicle 1 in four-wheel drive mode immediately after the engine is started 11 This is because the four-wheel drive operating mode is selected by a switching operation of the driver. Examples include the case where the starter switch is turned on in a state where the temperature of the control device... 2 high includes a case in which the starter switch is temporarily turned off after a long period of driving and then the four-wheel drive vehicle 1 It restarts after a short parking period.
[0090] According to the first embodiment described above, the zero-point adjustment processing is performed at predetermined time intervals. Consequently, it is possible to determine the accuracy of the control current supplied by the control device. 2 to spend in order to replace each of the first and second friction clutches 62R and 62L to control, to increase. Accordingly, it is possible to control the driving force that goes to each of the rear wheels. 14R and 14L to transmit, to control with high accuracy.
[0091] According to the first embodiment, the zero-point adjustment is performed in the separate operating mode when the first predetermined time, which is shorter than the second predetermined time, has elapsed. Consequently, the zero-point adjustment is performed at least once, even if the separate operating mode continues only for a short period. If the separate operating mode continues thereafter, the zero-point adjustment is performed repeatedly each time the second predetermined time, which is longer than the first predetermined time, has elapsed. Consequently, even after the temperature of the control device 2 The accuracy of the control current fluctuates during driving in the separate operating mode when the four-wheel drive vehicle is in operation. 1 when switching to four-wheel drive mode, the increase in the computational load on the CPU of the control device is increased. 2 is suppressed.
[0092] Next, a second embodiment of the present invention will be described with reference to Fig. 8 described. Fig. Figure 8 shows a structural diagram that schematically illustrates an example of the setup of a hydraulic circuit. 70A and a control device 2A illustrated according to the second embodiment. Fig. 8 Components that are common to those described in the first embodiment are designated by the same reference numerals as those in Fig. 7 or similar, to omit a redundant description.
[0093] The hydraulic circuit 70A According to this embodiment, each includes the first and second hydraulic pumps. 71R and 71L as well as first and second electric motors 72R and 72L , which are configured, each the first and second hydraulic pumps 71R and 71Lto power the first electric motor 72R is connected to the first hydraulic pump 71R through a first coupling wave 721R coupled and is capable of powering the first hydraulic pump 71R to rotate in forward and reverse directions. The second electric motor works in a similar way. 72L with the second hydraulic pump 71L through the second coupling wave 721L coupled and is able to operate the second hydraulic pump 71L to turn in forward and backward directions.
[0094] The first and second hydraulic pumps 71R and 71L , the first and second electric motors 72R and 72L and the right and left pistons 67 form a pressing mechanism 7A , which is configured, the outer coupling plates 621 and the inner coupling plates 622 the first and second friction clutches 62R and 62Lto press in the axial direction. The piston 67 presses the outer coupling plates 621 and the inner coupling plates 622 , by increasing the hydraulic pressure of the hydraulic oil that flows through the cylinder chamber 604 is supplied, is received.
[0095] The control device 2A According to this embodiment, a current output circuit comprises 20A and a control unit 200A The current output circuit 20A supplies motor currents, which serve as the control currents, to the first and second electric motors 72R and 72L the press mechanism 7A off. The control unit 200A includes a current monitoring device 21A , a target current value calculation device 22A and a power control device 23A .
[0096] When the driving forces are directed to the rear wheels 14R and 14Lvia the first and second friction clutches 62R and 62L The first and second electric motors generate the power that is transmitted in each case. 72R and 72L Torques corresponding to the motor currents supplied by the current output circuit 20A are output, thereby the first and second hydraulic pumps 71R and 71L to be rotated in the forward direction. The first and second hydraulic pumps 71R and 71L lead to the cylinder chambers 604 Flows of hydraulic oil at pressures corresponding to the torques exerted by the first and second motors 72R and 72L Each one is generated.
[0097] If the drive power transmission system 10 When the system switches to separate operating mode, the first and second electric motors rotate. 72R and 72L the first and second hydraulic pumps 71R and 71Lin the reverse direction, to change the pressures in the cylinder chambers 604 to reduce each one. Each of the first and second hydraulic pumps 71R and 71L pumps the hydraulic oil from the reservoir 710 during the forward direction, it rises and pushes the hydraulic oil to the reservoir 710 during the reverse rotation.
[0098] In the control unit 200A The electricity monitoring device records 21A the motor currents that actually go to the first and second electric motors 72R and 72L will be output. The target current value calculation device 22A It calculates target values (target current values) of the motor currents for the first and second electric motors. 72R and 72L to be supplied, based on measured values from the wheel speed sensor 17 and the acceleration device opening degree sensor 18 The power control device23A controls the power output circuit 20A such that the motor currents exhibiting the target current values are determined by the Stoll current value calculation device 22A through a regulation based on the results of a recording by the electricity recording device 21A is executed, calculated, to the first and second electric motors 72R and 72L will be issued.
[0099] The power control device 23A performs a processing operation similar to the processing operation according to the flowchart shown in the first embodiment with reference to Fig. 7 is described. At predetermined times based on timer values from the first timer and the second timer, the current control device executes 23A a zero-point adjustment for storing information that the detection signal from the current detection device21A is output and indicates the current value of the motor current, indicates a zero point of the control current which is determined by the current output circuit 20A to be spent.
[0100] The second embodiment described above achieves actions and effects similar to those described in the first embodiment.
[0101] Next, a third embodiment of the present invention will be described with reference to Fig. 9 and Fig. 10 described. Fig. Figure 9 shows a structural diagram illustrating the schematic design of a four-wheel drive vehicle. 1B illustrated according to the third embodiment of the present invention. A second drive force transmission device 9 and a control device 2B are in the four-wheel drive vehicle 1B attached. The control device 2Bcontrols the first drive power transmission device 4 and the second drive force transmission device 9 . Fig. Figure 10 shows a sectional view illustrating an example of the construction of a coupling device. 91 the second drive force transmission device 9 illustrated by the four-wheel drive vehicle 1B is appropriate. In Fig. 9 Components that are common to those described in the first embodiment are designated by the same reference numerals as those in Fig. 1 or similar, to omit a redundant description.
[0102] The second drive force transmission device 9 includes a differential device 90 and the coupling device 91 on the back. The differential device 90 and the coupling device 91 are connected by a pinion shaft 910coupled. The coupling device 91 is able to control the driving force that goes to the differential device 90 via the pinion shaft 910 to transmit, connect, and disconnect. The differential device 90 distributes the transmitted drive force to the drive axles 16R and 16L the rear wheels 14R and 14L , while differential motion is possible.
[0103] The differential device 90 includes a rear differential housing 900 , a pinion shaft 901 , which is configured to fit together with the rear differential housing 90 to turn a pair of pinion gears 902 , which are rotatable via the pinion shaft 901 to be held, and a pair of axle shaft wheels 903 , which are connected to the pinion gears 902are engaged, with the associated gear shafts positioned orthogonally to each other. The drive shafts 16R and 16L are each attached to the axle shaft wheels 903 coupled.
[0104] The coupling device 91 is roughly through a clutch housing 92 , which serves as an external rotating element that is attached to the drive shaft 5 coupled, an internal wave 93 , which serves as an internal rotating element that passes through the clutch housing 92 is held to be coaxial with respect to the coupling housing 92 to be rotatable, a main clutch 94 , which is a multi-disc clutch that is configured to have the clutch housing 92 and the inner wave 93 to couple them together by receiving an axial pressing force so that the drive force can be transmitted between them, a pilot coupling or pre-control coupling. 95, side by side with the main clutch 94 arranged in a corresponding axial direction, an electromagnetic actuating device 96 , which is configured, the pilot coupling 95 to cause an axial pressing force to be applied, and a cam mechanism 97 formed, which is configured, a torque of the clutch housing 92 , which is through the pilot coupling 95 is transferred into a pressing force for the main clutch 94 to convert.
[0105] As it is in Fig. As illustrated in 10, the clutch housing 92 through a cylindrical front housing provided with a base 921 and a ring-shaped rear housing 922 formed, which is attached to the front casing 921 is coupled by being engaged with an associated open end by means of a thread, in order to connect with the front housing. 921to turn. A multitude of wedge teeth. 921a is on the inner peripheral surface of the front case 921 formed along a rotational axis O. The drive shaft 5 is attached to a floor 921b of the front case 921 coupled.
[0106] The rear casing 922 is formed by a first element 922a , which is attached to the front casing 921 coupled and made of a soft magnetic material, a second element 922b , which is attached to an inner peripheral side of the first element 922a is coupled and is made of a non-magnetic material, such as austenitic stainless steel, and a third element 922c formed, which is attached to an inner peripheral side of the second element 922b is coupled and is made of a soft magnetic material.
[0107] The inner wave 93is on an inner side of the front case 921 arranged and supported by a ball bearing 981 and a needle bearing 982 Rotating mechanism. A multitude of wedge teeth. 93a is along the axis of rotation O on the outer peripheral surface of the inner shaft 93 trained, who are closer to the ground 921b of the front case 921 is arranged. A multitude of wedge-shaped pass sections. 930 is on the inner peripheral surface of the inner wave 93 formed at the end opposite to the ground 921b of the front case 921 is arranged. The wedge-shaped sections 930 couple one end of the pinion shaft 910 (see Fig. 9) to the inner wave 93 , so that the pinion shaft 910 and the inner wave 93 are not rotatable relative to each other.
[0108] The main clutch 94includes a variety of external main coupling plates 941 , which are configured to fit together with the front casing 921 to rotate, and a variety of internal main coupling plates 942 , which are configured to align themselves with the inner wave 93 to rotate. The outer main coupling plates 941 exhibit a multitude of intervention protrusions 941a up, which have wedge-shaped teeth 921a of the front case 921 are engaged, being non-rotatable but axially movable with respect to the front housing 921 are. The inner main coupling plates 942 exhibit a multitude of intervention protrusions 942a up, which have wedge-shaped teeth 93a the inner wave 93 are engaged, being non-rotatable but axially movable with respect to the inner shaft 93 are.
[0109] The pilot coupling 95 includes outer pilot coupling plates951 and inner pilot coupling plates 952 , which are arranged alternately along the axis of rotation O. The outer pilot coupling plates 951 exhibit a multitude of intervention protrusions 951a up, which have wedge-shaped teeth 921a of the front case 921 are engaged, interlocking with the front casing 921 are engaged in such a way that they are not rotatable but axially movable in relation to the front housing 921 to be. The inner pilot coupling plate 952 exhibits a multitude of intervention protrusions 952a on, which are equipped with a multitude of wedge teeth 971b are engaged, which are located on the outer peripheral surface of a pilot cam 971 of the cam mechanism 97 are trained, as described below, using the pilot cam 971 are engaged in order to be non-rotatable but axially movable with respect to the pilot cam 971 to be.
[0110] The electromagnetic actuator 96 includes an electromagnetic coil 961 and an anchor 962 The electromagnetic coil 961 receives an excitation current from an electrical cable 960 The electromagnetic coil 961 is between the first element 922a and the third element 922c of the rear case 922 arranged. The anchor 962 is arranged in such a position that it engages the pilot coupling 95 between the anchor 962 and part of the rear case 922 , which is the second element 922b encompasses, confines. The electromagnetic coil 961 is passed through a yoke 963 held by the third element 922c of the rear case 922 via a ball bearing 983 is held.
[0111] A multitude of intervention points 962ais on the outer peripheral surface of the anchor 962 provided. The intervention advantages 962a are equipped with wedge teeth 921a of the front case 921 in action. Thus, the anchor is 962 not rotatable but axially movable in relation to the front housing 921 .
[0112] The outer pilot coupling plates 951 and the inner pilot coupling plates 952 are made of a soft magnetic material, so that a magnetic flux, which is supplied with energy to the electromagnetic coil 961 is generated, can pass through. If the excitation current from the control device 2B to the electromagnetic coil 961 When a magnetic flux is supplied, it is generated in a magnetic path G that passes through the yoke. 963 , the first element 922a and the third element 922c of the rear case 922 , the outer pilot coupling plates951 , the inner pilot coupling plates 952 and the anchor 962 passes through it. The anchor 962 is directed towards the rear of the casing 922 attracted by the magnetic force of the magnetic flux.
[0113] The pilot coupling 95 is caused by the axial movement of the anchor 962 pressed, whereby the outer pilot coupling plates 951 and the inner pilot coupling plates 952 They are brought into frictional contact with each other. This results in a torque being applied to the front housing. 921 to the pilot cam 971 transmitted. The torque that goes to the pilot cam 971 The amount of energy to be transmitted changes according to the excitation current supplied to the electromagnetic coil. 961 is supplied.
[0114] The cam mechanism 97 includes the pilot cam 971 and a main cam 972, which serve as a pair of cam elements, as well as a variety of cam balls 973 , which are between the pilot cam 971 and the main cam 972 are arranged. The pilot cam 971 and the main cam 972 are coaxial to the coupling housing 92 and the inner wave 93 arranged. A relative rotation between the main cam 972 and the inner wave 93 is limited in such a way that a large number of intervention advantages 972b , located on the inner peripheral surface of the main cam 972 are formed, with the wedge-shaped teeth 93a the inner wave 93 are engaged. A needle thrust bearing 984 is between the pilot cam 971 and the third element 922c of the rear case 922 arranged.
[0115] cam grooves 971a are at the pilot cam 971 designed in such a way that the cam balls973 along the cam grooves 971a roll. Cam grooves 972a are at the main cam 972 designed in such a way that the cam balls 973 along the cam grooves 972a roll. The cam grooves 971a and 972a the pilot cam 971 and the main cam 972 They extend along the circumferential direction in a predetermined angular range and are designed such that the axial depth is greatest at the center and smallest towards the ends.
[0116] In the coupling device 91 , which is constructed as described above, will be when the excitation current is supplied by the control device 2B to the electromagnetic coil 961 is supplied, the anchor 962 towards the rear of the casing 922 through the magnetic force of the electromagnetic coil 961 tightened to engage the pilot clutch 95to press. This allows the outer pilot coupling plates to slide. 951 and the inner pilot coupling plates 952 rubbing against each other, consequently increasing the rotational force of the front housing 921 to the pilot cam 971 of the cam mechanism 97 via the pilot coupling 95 is transmitted. Accordingly, the pilot cam rotates. 971 with regard to the main cam 972 .
[0117] When the cam balls 973 along the cam grooves 971a and 972a through the relative rotation between the pilot cam 971 and the main cam 972 When rolling, an axial thrust is generated in the main cam. 972 generated so that the main cam 972 away from the pilot cam 971 moved. The thrust of the cam mechanism 97 causes the main cam 972 , the main clutch 94to press, consequently creating a frictional force between the outer main coupling plates 941 and the inner main coupling plates 942 is generated. Accordingly, the front housing 921 and the inner wave 93 coupled to each other in such a way that the driving force can be transmitted between them.
[0118] If the supply of the excitation current from the control device 2B to the electromagnetic coil 961 If the pilot clutch is interrupted 95 not through the anchor 962 pressed, consequently the torque does not come from the front housing 921 to the pilot cam 971 via the pilot coupling 95 is transferred. Thus, the main clutch 94 not through the main cam 972 pressed. Accordingly, the drive force is not applied to the main clutch. 94 transmitted.
[0119] The pilot coupling 95, the electromagnetic actuating device 96 and the cam mechanism 97 form a pressing mechanism 911 , which is configured, the outer main coupling plates 941 and the inner main coupling plates 942 the main clutch 94 in the axial direction by the pressing force according to the excitation current supplied by the control device 2B The excitation current supplied to the electromagnetic coil is used to press the coil. 961 The current supplied is a control current that is fed from the control device 2B to the press mechanism. 911 is output to provide the driving force that passes through the main clutch 94 to transfer, to regulate.
[0120] The control device 2B includes a power output circuit 20B and a control unit 200B The current output circuit 20Bsupplies the excitation current, which serves as the control current, to the electromagnetic coil 961 the electromagnetic actuating device 96 off. The control unit 200B includes a current monitoring device 21B , which is configured to output a detection signal corresponding to the magnitude of the excitation current actually supplied by the current output circuit 20B A target current value calculation device is output. 22B , which is configured to calculate a target current value, which is a target value of the excitation current supplied to the pressing mechanism 911 to be supplied, and a power control device 23B , which is configured, the power output circuit 20B to control in such a way that the excitation current, which has the current value determined by the target current value calculation device, 22Bcalculated on the basis of a result of a measurement taken by the electricity measurement device 21B is executed, to the press mechanism 911 is issued.
[0121] The power output circuit 20B is similar to the power output circuit 20 constructed according to the first embodiment, which refers to Fig. 6 is described, with the exception that the excitation current, which serves as the control current, is the electromagnetic coil 961 is supplied. The current monitoring device 21B , the target current value calculation device 22B and the power control device 23B They perform respective types of processing similar to those of the current sensing device. 21 , the target current value calculation device 22 and the power control device 23are those described in the first embodiment. At predetermined times, based on timer values from the first and second timers, the current control device executes 23B a zero-point adjustment for storing information that the detection signal from the current detection device 21B is output, and indicates the current value of the excitation current, indicates a zero point of the control current, which is determined by the current output circuit 20B to be spent.
[0122] The third embodiment described above achieves actions and effects similar to those of the first embodiment. An electric motor can serve as the electromagnetic actuator. 96 The pilot cam is used, which is configured. 971 and the main cam 972 of the cam mechanism 97to rotate relative to each other. In this case, the pilot cam rotates. 971 with regard to the main cam 972 by a torque of the electric motor, whereby the main cam 972 the main clutch 94 The motor presses by applying a pressing force corresponding to a motor current. The control device supplies the motor current, which serves as the control current, to the electric motor. Furthermore, an electromagnetic solenoid can be used as the electromagnetic actuating device. 96 be used.
[0123] The present invention can be suitably modified without deviating from the scope of the present invention. The components of the respective embodiments can be suitably combined. For example, two coupling devices can be 91 according to the third embodiment, instead of the first and second friction clutches 62R and 62Lthe second drive force transmission device 6 according to the first embodiment. Furthermore, the second drive force transmission device, in which the outer clutch plates and the inner clutch plates are pressed by the hydraulic pressure, can be used between the differential device. 90 on the rear side and the drive shaft 5 be arranged as it is in Fig. Figure 9 illustrates this. Alternatively, the arrangement of the coupling device can be... 91 in the third embodiment, the coupling device is modified. 91 can be used to distinguish between the differential device 90 and the drive axle 16R or the drive axle 16L be arranged.
[0124] A control device ( 2 ) for a four-wheel drive vehicle includes a current sensing device ( 21), which is configured to output a detection signal corresponding to the magnitude of an actual control current, a target current value calculation device ( 22 ), which is configured to calculate a setpoint current value, which is a setpoint of the control current, and a current control device ( 23 ), which is configured to be a power output circuit ( 20 ) to control, to output the control current which has the target current value determined by the target current value calculation device ( 22 ) is calculated based on the result of a measurement taken by the electricity measurement device ( 21 ) is executed. If the four-wheel drive vehicle is in a two-wheel drive operating mode, in which the first and second friction clutches ( 62R , 62L ) are released, the power control device ( 23) a zero-point adjustment for adjusting a zero point of the control current supplied by the current output circuit ( 20 ) to be spent, out. QUOTES INCLUDED IN THE DESCRIPTION
[0125] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature
[0126] JP 2013-164099 A [0002, 0004] JP 2009-269605 A
[0002] JP 2009269605 A
[0004]
Claims
[1] Four-wheel drive vehicle with: Main drive wheels, to which a driving force from a drive source is constantly transmitted; a drive shaft configured to transmit the drive force in a front-and-rear direction of the vehicle; Auxiliary drive wheels, to which the driving force of the drive source is transmitted via the drive shaft; a first drive power transmission device and a second drive power transmission device arranged such that the drive shaft is inserted between the first drive power transmission device and the second drive power transmission device in a drive power transmission path to the auxiliary drive wheels; and a control device configured to control the first drive force transmission device and the second drive force transmission device, wherein the first drive force transmission device comprises a jaw coupling configured to transmit the drive force by engagement between projections and recesses, The second drive force transmission device includes: an outer rotating element and an inner rotating element, which are held in such a way as to be rotatable coaxially with respect to each other; an outer coupling plate configured to rotate together with the outer rotating element; an inner coupling plate configured to rotate together with the inner rotating element; and a pressing mechanism configured to press the outer coupling plate and the inner coupling plate in an axial direction by a pressing force corresponding to a control current supplied by the control device, The control device includes: a power output circuit configured to output the control current to the pressing mechanism; a current sensing device configured to output a sensing signal corresponding to a magnitude of the control current actually output by the current output circuit; a target current value calculation device configured to calculate a target current value, which is a target value of the control current to be supplied to the pressing mechanism; and a current control device configured to control the current output circuit such that the control current, which has the current value calculated by the set current value calculation device based on a result of a sensing performed by the current sensing device, is output to the press mechanism, and, When the four-wheel drive vehicle is in a two-wheel drive operating mode in which transmission of the drive force performed by both the first drive force transmission device and the second drive force transmission device is interrupted, the current control device is configured to perform a zero-point adjustment for storing information that the sensing signal output by the current sensing device indicates a zero point of the control current to be output by the current output circuit. [2] Four-wheel drive vehicle according to claim 1, wherein the current control device is configured to perform the zero point adjustment when a first predetermined time has elapsed since the four-wheel drive vehicle was switched to the two-wheel drive mode, and, if the two-wheel drive mode continues thereafter, to perform the zero point adjustment repeatedly each time a second predetermined time, which is longer than the first predetermined time, has elapsed. [3] Four-wheel drive vehicle according to claim 1 or 2, wherein, when a starter switch is turned on to start the drive source, the current control device is configured to perform the zero point adjustment before the control current is output from the current output circuit to the press mechanism. [4] Four-wheel drive vehicle according to any one of claims 1 to 3, wherein the press mechanism comprises: a hydraulic pump; a piston configured to press the outer clutch plate and the inner clutch plate by receiving hydraulic pressure from a hydraulic oil supplied to a cylinder chamber; and a solenoid valve configured to regulate the pressure of the hydraulic oil supplied from the hydraulic pump to the cylinder chamber, and The control device is configured to output the control current to the solenoid valve. [5] Four-wheel drive vehicle according to any one of claims 1 to 3, wherein the press mechanism comprises: an electric motor; a hydraulic pump to be driven by the electric motor; and a piston configured to press the outer clutch plate and the inner clutch plate by receiving hydraulic pressure from a hydraulic oil supplied by the hydraulic pump to a cylinder chamber, and The control device is configured to output the control current to the electric motor. [6] Four-wheel drive vehicle according to any one of claims 1 to 3, wherein the press mechanism comprises: a cam mechanism configured to generate the pressing force by a relative rotation between a pair of cam elements arranged coaxially with the outer rotating element and the inner rotating element; and an electromagnetic actuating device configured to rotate the pair of cam elements relative to each other, and The control device is configured to output the control current to the electromagnetic actuator. [7] Control device to be fitted to a four-wheel drive vehicle, comprising the main drive wheels to which a driving force from a drive source is constantly transmitted, a drive shaft configured to transmit the driving force in a front-and-rear direction of the vehicle, auxiliary drive wheels to which the driving force from the drive source is transmitted via the drive shaft, and a first drive force transmission device and a second drive force transmission device arranged such that the drive shaft is inserted between the first drive force transmission device and the second drive force transmission device in a drive force transmission path to the auxiliary drive wheels, the control device comprising: a control unit; and a current output circuit, wherein the control device is configured to control the first drive force transmission device and the second drive force transmission device, the first drive force transmission device comprises a jaw coupling configured to transmit the drive force by engagement between projections and recesses, The second drive force transmission device includes: an outer rotating element and an inner rotating element, which are held in such a way as to be rotatable coaxially with respect to each other; a friction clutch comprising an outer clutch plate configured to rotate together with the outer rotating element, and an inner clutch plate configured to rotate together with the inner rotating element; and a pressing mechanism configured to press the outer coupling plate and the inner coupling plate in an axial direction by a pressing force corresponding to a control current supplied by the control device, The control device includes: a target current value calculation device configured to calculate a target current value, which is a target value of the control current to be supplied to the pressing mechanism; a current sensing device configured to output a sensing signal corresponding to a magnitude of the control current actually output by the current output circuit; and a current control device configured to control the current output circuit such that the control current, which has the current value calculated by the set current value calculation device based on a result of a sensing performed by the current sensing device, is output to the press mechanism, and, When the four-wheel drive vehicle is in a two-wheel drive operating mode in which transmission of the drive force, which is carried out by both the dog clutch and the friction clutch, is interrupted, the current control device is configured to perform a zero-point adjustment for storing information that the sensing signal output by the current sensing device indicates a zero point of the control current to be output by the current output circuit.