JP4670247B2 - Driving force transmission device - Google Patents

Description

  The present invention relates to a driving force transmission device used in a differential mechanism that controls the rotational speed of front and rear wheels of a vehicle.

  2. Description of the Related Art Conventionally, in a differential mechanism used for vehicle coupling or the like, a driving force transmission device that limits differential is provided in order to prevent idling (slip state) of some drive shafts. There exists a thing like patent document 1, for example.

  This is an electromagnetic clutch device as a driving force transmission device that limits the differential of the differential device. This electromagnetic clutch device includes a multi-plate main clutch 75 disposed between the sun gear 53 and the planetary gear carrier 47, a multi-plate pilot clutch 87 disposed between the differential case 31 and the cam member 77, and a cam member as a cam mechanism. 77, a ball cam 78 provided between the planetary gear carrier 47, an armature 93 disposed adjacent to the pilot clutch 87, and an electromagnet 89 disposed outside the differential case 31.

  In this conventional example, a controller (not shown) performs excitation of the electromagnet 89, control of the excitation current, and the like according to the vehicle speed, turning, or road surface condition. When the electromagnet 89 is excited, the armature 93 is attracted, the pilot clutch 87 is engaged, and a pilot torque is generated. In the state where the pilot torque is generated, for example, when a differential rotation occurs in the differential mechanism during traveling on a rough road, starting, acceleration, etc., the cam member 77 connected to the differential case 31 via the pilot clutch 87. Then, the differential torque is transmitted from the planetary gear carrier 47 to the ball cam 78, receives the generated cam thrust force, moves the planetary gear carrier 47 in the rotation axis direction, and presses and fastens the main clutch 87. In this way, the rotational torque is transmitted without the differential between the drive shaft side and the driven shaft side.

Moreover, there exists a thing like patent document 2. FIG. In the first drive axle (drive shaft), when the sensor detects the occurrence of slip or the possibility of slip, the motor 88 is activated by the electronic torque control device on the second drive axle (driven shaft) side. The rotational force from the motor 88 is transmitted to the second ramp member (cam member) 76 via the gear set 86, and the second ramp member 76 and the first ramp member (cam member) 74 are rotated relative to each other. The side gear pressure plate 56 is moved in the direction of the axial clutch pack (clutch) 68. By this axial movement, the friction plates 70 are compressed with each other, whereby the clutch pack 68 is connected and a predetermined amount of torque is transmitted from the first drive axle to the second drive axle. As long as the sensor detects that more driving force is required on the second driving axle, the torque by the motor 88 is continuously applied and the engaged state of the clutch pack 68 is maintained.
Japanese Patent No. 2820161 (page 7, FIG. 1 (a)) JP 2003-287106 A (page 9 to page 11, FIGS. 2, 5, and 6)

  In the apparatus described in Document 1, in order to press the clutch with the cam mechanism, a differential between the drive shaft side and the driven shaft side is assumed. Therefore, when starting without a differential, the torque is not transmitted to all the axles, but the torque is transmitted to all the axles only after the differential is generated after starting, and the response at the start may be delayed. Similarly, since the torque is transmitted only after the differential due to the slip occurs, the response in the slip state may be delayed.

In the apparatus described in the above-mentioned document 2, since the clutch is pressed by the cam mechanism, the differential between the drive shaft side and the driven shaft side is not assumed. However, when the slip state disappears, when it is desired to transmit torque from the first drive axle (drive shaft) to the second drive axle (driven shaft), for example, in advance, muddy, snowy road, sandy ground For example, when stable running on a slippery road surface is desired, there is a problem in that electricity for driving the motor must continue to flow, so that electricity is consumed significantly and battery consumption is accelerated.
The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a driving force transmission device that enables a quick response of torque transmission at the time of starting and slipping and that consumes less electricity. is there.

To solve the problems described above, characteristics of the driving force transmission apparatus according to claim 1, provided between the drive shaft and the driven shaft, the rotational axis to restrict the relative rotation with respect to the drive shaft A clutch comprising an outer clutch or an inner clutch provided so as to be movable in a parallel direction and an inner clutch or an outer clutch provided so as to be movable in a direction parallel to the rotation axis while restricting relative rotation with respect to the driven shaft. When, a second cam member of the cam mechanism that is movable relative rotation in a direction parallel to the axis of rotation is regulated with respect to the drive shaft to the drive shaft, the second to the cam member and the relative rotation linked via the first in the driving force transmission apparatus that includes a cam member, said first cam member and said second cam member to the drive shaft of the cam mechanism for relatively moving the second cam member in the rotational axis direction by Was A first rotary shaft, a second rotating shaft connected the driven shaft, provided with a differential device having a third rotating shaft connected to the motor, the differential device at the time of the motor drive, the motor transmitted to the first cam member by transmitting torque from the third rotary shaft to the first rotation shaft via the second rotary shaft, the torque of the motor by the relative movement of the first and the second cam member The clutch is pressed against the clutch, and when the motor is not driven, the third rotating shaft is rotated by a differential based on a difference in the rotational speed generated between the driving shaft and the driven shaft. Rotating the motor to generate a counter-torque in the motor, and transmitting the counter-torque from the third rotating shaft to the first rotating shaft through the second rotating shaft; The first and second caps The relative movement of the member is to press the clutch.

  The driving force transmission device according to claim 2 is characterized in that, in claim 1, the differential device is a planetary gear mechanism.

  According to a third aspect of the present invention, there is provided a driving force transmission device according to the first or second aspect, wherein a speed reduction device is provided between the motor and the third rotating shaft.

  The driving force transmission device according to claim 4 is characterized in that an inner shaft rotatably supported on the same rotational axis on a housing rotatably supported by a differential case, and between the inner periphery of the housing and the outer periphery of the inner shaft. A clutch housing chamber formed on the inner peripheral surface of the housing, an outer clutch plate engaged with the engaging portion formed on the inner peripheral surface of the housing so as to be able to move in a direction parallel to a rotation axis while restricting relative rotation. An inner clutch plate that is arranged alternately with the clutch plate and that is engaged with the outer peripheral surface of the inner shaft so as to be able to move in a direction parallel to the rotation axis by restricting relative rotation, and an inner peripheral surface of the housing. The second cam member engaged with the engaging portion so as to be able to move in a direction parallel to the rotation axis while restricting relative rotation to the engaging portion and loosely fitted to the outer periphery of the inner shaft The first cam member connected to the second cam member via the cam floor is provided, and includes the outer clutch plate and the inner clutch plate, and the first cam member and the second cam member are rotated relative to each other. A driving force transmission device that presses the outer clutch plate and the inner clutch plate by axial movement of the second cam member generated in response to the first sun gear that is externally fitted to the inner shaft so as not to move relatively; A first planetary gear mechanism having a first ring gear having outer teeth formed on the outer periphery, and a first carrier that rotates in conjunction with the rotation of the first sun gear and the first ring gear; and the outer teeth of the first ring gear A drive shaft is rotatably connected to the motor and is fixed to the differential case, and is integrally formed with the first cam member. A second sun gear, a second ring gear provided in the differential case so as not to move relative to the differential case, and a second ring gear connected to the first carrier so as not to move relative to each other and rotating in conjunction with rotation of the second sun gear and the second ring gear. And a second planetary gear mechanism having two carriers.

  In the driving force transmission device according to the first aspect, there is no differential between the driving shaft and the driven shaft when the vehicle starts from a stopped state. At this time, the rotation of the driven shaft is performed on the second rotating shaft. The resistance is very large and the second rotating shaft is substantially fixed. Therefore, the motor torque is supported by a reaction force on the second rotating shaft and rotates the first rotating shaft. Then, the torque of the motor can be amplified by the relative movement of the first and second cam members and the clutch can be pressure-contacted so that the torque of the drive shaft can be transmitted to the driven shaft. Therefore, at the time of starting, the torque of the drive shaft can be transmitted to the driven shaft with a quick response without delay.

  When the vehicle is in a traveling state at a stable speed after starting, generally, a difference is generated between the drive shaft and the driven shaft, so that the first rotation shaft or the second rotation shaft rotates from the drive shaft or the driven shaft, respectively. Each rotation difference is transmitted to the motor connected to the third rotating shaft by the differential device. If no resistance is generated in the motor, the motor rotates freely. When it is desired to transmit torque to the driven shaft, a counter torque as a regenerative brake is generated in the motor. The counter torque is transmitted to the first cam member connected to the first rotating shaft by the differential device, and the counter torque is amplified by the relative movement of the first and second cam members to press the clutch. The torque of the drive shaft can be transmitted to the driven shaft. Therefore, the response of torque transmission is not delayed at the time of slip. Furthermore, since the motor generates power simultaneously when used as a regenerative brake, it can be charged as well as reducing electricity consumption, and battery consumption can be prevented.

  In the driving force transmission device according to the second aspect, since the planetary gear mechanism is used as the differential device, a driving force transmission device having a simple structure and saving space can be obtained.

  In the driving force transmission device according to the third aspect, since the torque of the motor can be amplified by the speed reducer and transmitted to the cam mechanism via the differential device, a small and lightweight motor that generates a small torque is used. The driving force transmission device can be activated.

  In the driving force transmission device according to the fourth aspect, at the time of starting, first, the motor is driven to rotate the first ring gear. At this time, the torque of the motor is amplified and transmitted to the first ring gear by the drive gear functioning as a reduction gear and the external teeth of the first ring gear. In the first planetary gear mechanism, the rotation of the first ring gear is transmitted to the first carrier. This is because the first sun gear connected to the driven shaft is in a fixed state, so that the first carrier rotates due to the reaction force and the torque of the first ring gear. In the second planetary gear mechanism, the second carrier connected to the first carrier so as not to move relative to the first carrier rotates. Here, when the second carrier rotates, the first cam member as the second sun gear rotates. This is because the second ring gear is fixed to the front differential case, and the counter torque generated from the second ring gear and the torque for rotating the second carrier rotate the first cam member. By this torque, the first cam member and the second cam member are relatively rotated, and the second cam member is moved in the axial direction. By the movement of the second cam member, the outer clutch plate is moved in a direction parallel to the rotation axis, and is brought into pressure contact with the inner clutch plate. Thereby, torque transmission is performed between the housing and the inner shaft. Thus, at the time of starting, it is possible to quickly respond without delay and transmit the torque of the drive shaft to the driven shaft, so that the starting performance is improved.

  When the vehicle is in a traveling state at a stable speed after starting, a differential is generally generated due to wheel slip or the like. However, the rotational speeds of the second sun gear connected to the drive shaft and the first sun gear connected to the driven shaft are different. In response to the difference, the first ring gear rotates via the first gear mechanism and the second gear mechanism. When the first ring gear rotates, the rotation is transmitted to the motor by the drive gear connected to the first ring gear. Here, when no resistance is generated in the motor, the motor rotates freely. When it is desired to transmit torque to the driven shaft, a counter torque as a regenerative brake is generated in the motor. This counter torque is amplified by the drive gear and the external gear of the first ring gear and transmitted to the first ring gear. Further, this counter torque is transmitted to the first cam member via the first gear mechanism and the second gear mechanism. Next, the first cam member and the second cam member are relatively rotated, the second cam member is moved in the axial direction, the inner clutch plate and the outer clutch plate are frictionally engaged, and the drive shaft and the driven shaft are Torque is transmitted between the two.

  Therefore, during stable running after starting, torque can be transmitted between the drive shaft and the driven shaft by the differential between the drive shaft and the driven shaft. There is no delay. Further, since the motor acts as a generator at the same time when used as a regenerative brake, it can not only consume electricity but also be charged, and the consumption of the storage battery can be prevented.

  An embodiment of a driving force transmission device according to the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram when the driving force transmission device is used in a four-wheel drive vehicle, FIG. 2 is a block diagram showing a control device, and FIG. 3 is a sectional view of the driving force transmission device.

  For example, in a four-wheel drive vehicle, the driving force transmission device 1 includes a propeller shaft 31 and a rear differential mechanism 32 to distribute and control the driving force of the engine 30 to the rear wheels, which are driven wheels, as shown in FIG. Intervening in between. The output torque of the engine 30 is output to the front axle shaft 34 via the front differential mechanism 33 to drive the left and right front wheels Wfl and Wfr which are drive wheels and to the propeller shaft 31. The propeller shaft 31 is connected to the rear differential mechanism 32 on the driven shaft side via the driving force transmission device 1. The driving force transmission device 1 is controlled on the basis of the command torque calculated by the electronic control device 35 according to the traveling state of the vehicle, and is output to the rear axle shaft 36 to distribute the command torque to the rear wheels Wrl and Wrr.

  Further, wheel speed sensors Sfl, Sfr, Srl, Srr for detecting the wheel speeds of the driving wheels Wfl, Wfr and the driven wheels Wrl, Wrr are provided corresponding to the respective wheels.

  As shown in FIG. 2, the electronic control unit 35 is connected to the wheel speed sensors Sfl, Sfr, Srl, Srr and the current control circuit 37 of the motor 7 and to a generated current measuring sensor Se that detects the generated current of the motor 7. It is connected. The electronic control unit 35 includes a CPU that performs various arithmetic processes for controlling the current of the motor 7, a ROM that stores a control program, and the like.

  In FIG. 3, reference numeral 2 denotes a differential case, a front differential case 2a surrounding the outer periphery of the housing 3, and a rear differential case 2b that contacts the front differential case 2a and extends rearward to accommodate the differential device 32. It consists of. A sealed bearing 4 is provided on the inner periphery of the front differential case 2a on the propeller shaft 31 side, and the housing 3 is rotatably supported around the rotation axis O. A gear housing chamber 5 is formed on the side of the rear differential mechanism 32 of the front differential case 2a. The gear storage chamber 5 bulges outward from the rotating shaft by the rear differential case 2b. A motor mounting hole 6 is formed on the outer side of the gear housing chamber 5 on the side of the rear differential mechanism 32, and a motor 7 projects into the gear housing chamber 5 through the mounting hole 6 and the rotation axis O is connected to the motor housing hole 5. Installed in parallel. An external gear drive gear 8 is attached to the drive shaft of the motor 7, and the drive gear 8 meshes with the external gear of the first ring gear R1 in which gears are formed on both the inner periphery and the outer periphery. The first ring gear R1 is supported so as to be rotatable around the rotation axis O, and a first sun gear S1 provided on the outer periphery of the inner shaft 9 as a driven shaft to restrict relative movement is disposed at the center thereof. A plurality of planetary gears P1 are disposed between the one sun gear S1 and the first ring gear R1. The planetary gear P1 meshes with both the first sun gear S1 and the first ring gear R1, and revolves around the sun gear S1. It is housed in a frame called a first carrier C1 so as to be able to rotate together with a planetary gear P2 provided on the same rotation shaft, which will be described later, so as not to be relatively movable. The first ring gear R1, the planetary gear P1, the first sun gear S1, and the first carrier C1 constitute a first planetary gear mechanism PGM1.

  A second ring gear R2 is juxtaposed with the first ring gear R1 in the front differential case 2a, and the second ring gear R2 is screwed to the inner periphery of the end of the differential case 2a by a mounting screw 10. A first cam member S2 is loosely fitted on the outer periphery of the inner shaft 9 at the center of the ring gear R2, and an external gear is formed on the outer periphery of the first cam member S2, thereby forming a second sun gear. A needle bearing 11 is sandwiched between the first cam member S2 and the first sun gear S1, so that the first cam member S2 and the first sun gear S1 are relatively rotatable. A plurality of the planetary gears P2 are disposed between the first cam member S2 and the second ring gear R2, and mesh with both the external gear of the first cam member S2 and the internal gear of the second ring gear R2. . Further, the planetary gear P2 is housed in a frame called a second carrier C2 so as to be able to rotate together with the planetary gear P1 provided on the same rotational shaft as described above so as not to be relatively movable. The first carrier C1 and the second carrier C2 are connected at a plurality of locations by the rotation shafts of the planetary gear P1 and the planetary gear P2, and cannot be moved relative to each other. The second ring gear R2, the planetary gear P2, the first cam member (second sun gear) S2, and the second carrier C2 constitute a second planetary gear mechanism PGM2.

  The housing 3 is formed in a substantially cylindrical shape with a bottom, and a clutch housing space 12 filled with lubricating oil is provided in the housing 3. A screw hole 13a is screwed on the bottom outer wall of the housing 3, and the housing 3 is connected to the propeller shaft 31 via a stud bolt 13 that is screwed into the screw hole 13a. A bearing 14 is disposed in a recess formed in the inner periphery of the bottom of the housing 3, and the outer peripheral portion of the inner shaft 9 is rotatably supported by the bearing 14. A spline hole 15 is formed in the rear end portion of the inner shaft 9, and the pinion shaft 16 of the rear differential mechanism 32 is spline-engaged to integrally form the inner shaft 9 and the pinion shaft 16. This pinion shaft 16 is supported by a bearing 17 disposed in a recess formed in the inner periphery of the rear differential case 2b, and rotates together with an inner shaft 9 supported by the bearing 14 around a rotation axis O. It is possible.

  A clutch 20 including a plurality of outer clutch plates 18 and an inner clutch plate 19 is disposed in the clutch storage chamber 12. The outer clutch plate 18 is made of, for example, iron and is spline-engaged with an engaging portion 3 a formed on the inner peripheral surface of the clutch housing chamber 12. The outer clutch plate 18 restricts relative rotation with respect to the housing 3 and moves in a direction parallel to the rotation axis O. Has been made possible. The inner clutch plate 19 is configured by adhering a paper friction material to the surface of an iron core, and is spline-engaged with an engaging portion 9 a formed at the center of the outer peripheral surface of the inner shaft 9. On the other hand, the relative rotation is restricted and the movement in the direction parallel to the rotation axis O is possible. The outer clutch plates 18 and the inner clutch plates 19 are alternately arranged so as to come into contact with each other and frictionally engage when engaged, and are separated from each other and disengaged when disengaged.

  A cam mechanism 21 is disposed between the clutch housing chamber 12 and the gear housing chamber 5. The cam mechanism 21 includes the first cam member S2, the second cam member 22, and the cam floor 23. A plurality of cam grooves 24 facing each other are formed on the opposing surfaces of the first cam member S2 and the second cam member 22 at predetermined intervals in the circumferential direction, and a ball-shaped cam floor 23 is disposed in each cam groove 24. Has been. The second cam member 22 is spline-engaged with the engaging portion 3 a of the housing 3, and is capable of moving in a direction parallel to the rotation axis O by restricting relative rotation with respect to the housing 3. The first cam member S2 is loosely fitted to the inner shaft 9 as described above.

  According to the driving force transmission device 1 having the above-described configuration, when the vehicle starts from a stopped state, the drive shaft and the driven shaft are still in the stopped state, and no differential is generated. In this case, the motor 7 is driven to rotate the drive gear 8, and the first ring gear R1 meshed with the external gear is rotated. The first ring gear R1 of the first planetary gear mechanism PGM1 rotates the planetary gear P1 meshed with the inner periphery to transmit torque to the first sun gear S1 and the first carrier C1 connected to the inner shaft 9 as a driven shaft. In this case, since the rotational resistance of the inner shaft 9 is very large, the first sun gear S1 is substantially in a fixed state. The torque of the motor 7 is used to rotate the first carrier C1 with the reaction force supported by the first sun gear S1, and the first carrier C1 is the second carrier C2 of the second planetary gear mechanism PGM2 provided side by side. Therefore, the second carrier C2 rotates around the rotation axis O. Since the planetary gear P2 is also provided so as not to move relative to the planetary gear P1, the planetary gears P1 and P2 rotate at the same rotational speed. In the second planetary gear mechanism PGM2, since the second ring gear R2 is fixed to the front differential case 2a, the rotation of the second carrier C2 generates a torque that rotates the first cam member S2 that is the second sun gear. The first cam member S2 rotates relative to the second cam member 22 by the torque, and amplifies the torque of the motor 7 to move the second cam member 22 in the axial direction. Then, the inner clutch plate 19 and the outer clutch plate 18 are frictionally engaged. Thus, the clutch 20 can be pressed against the motor 7 with a force corresponding to the torque of the motor 7, and the torque controlled by the clutch can be transmitted from the housing 3 as the drive shaft to the inner shaft 9 as the driven shaft. Thus, at the time of starting, the torque of the drive shaft can be transmitted to the driven shaft in a quick response without delaying the starting operation, so that the starting performance is improved.

  When the vehicle travels at a stable speed, a differential occurs because the rotational speed of the drive shaft is generally greater than the rotational speed of the driven shaft due to wheel slip or the like. Then, the first ring gear R1 according to the differential rotation from the second sun gear (first cam member) S2 connected to the housing (drive shaft) 3 and the first sun gear S1 connected to the inner shaft (driven shaft) 9. Rotates.

  That is, the movement of the planetary gear mechanisms PGM1 and PGM2 that cause this differential will be described as follows with reference to the velocity diagram of FIG. In the speed diagram, the elements comprising the sun gear, the carrier and the ring gear of the planetary gear mechanism are arranged at intervals corresponding to the gear ratio in the horizontal axis direction, and the speed ratio is taken corresponding to each element in the vertical axis direction. Is. The speed ratio of the first sun gear S1, the first carrier C1, and the first ring gear R1 as the first planetary gear mechanism PGM1 is shown on the right side of the figure, and the first cam member (second second) as the second planetary gear mechanism PGM2 is shown on the left side. The speed ratio of the sun gear), the second carrier C2, and the second ring gear R2 is schematically shown.

  For example, when the second sun gear S2 rotates at a speed of 1, the rotational speed becomes differential by the differential rotational speed ΔN (speed ratio in FIG. 4), and the speed of the first sun gear S1 becomes the speed indicated by point a. In this case, since the second ring gear R2 is fixed, its speed becomes zero. In this case, a point b where the straight line connecting the speed 1 indicated by the vertical axis S2 and the speed 0 indicated by the vertical axis R2 intersects the vertical axis C2 is the rotational speed of the second carrier. At this time, since the first carrier C1 is connected to the second carrier C2 so as not to be relatively movable, the rotation speed of the first carrier C1 is the same as the speed indicated by the second carrier. Therefore, the point c at which the line extending from the point b in parallel with the horizontal axis and the vertical axis C1 intersect is the rotational speed of the first carrier. The point d where the straight line extending between point a, which is the speed of the first sun gear S1, and point c, which is the speed of the first carrier, and the vertical axis R1 is the rotational speed of the first ring gear R1. In this case, when the differential rotation speed ΔN increases on the vertical axis S1, the speed indicated by the point d on the vertical axis of R1 increases. Thus, the first ring gear R1 rotates according to the differential magnitude of the rotational speed.

  Thus, when the first ring gear R1 rotates, the rotation is transmitted to the motor 7 from the drive gear 8 connected to the first ring gear R1. Here, when no resistance is generated in the rotation of the motor 7, the motor 7 rotates freely. When this motor acts as a generator, the transmitted rotation causes the motor 7 to generate a counter torque as a regenerative brake.

  Next, this counter torque is amplified by a reduction gear (the drive gear 8 and the external gear of the first ring gear R1) and transmitted as a reaction force to the first ring gear R1. The counter torque is transmitted from the first ring gear R1 to the first carrier C1 and the second carrier C2. Further, the counter torque transmitted from the second carrier C2 is transmitted to the first cam member S2, and the first cam member S2 and the second cam member 22 are rotated relative to each other to move the second cam member 22 in the axial direction. . Then, the inner clutch plate 19 and the outer clutch plate 18 are frictionally engaged. In this way, the clutch 20 can be pressed into contact with the force corresponding to the counter-torque, and the torque controlled by the clutch 20 can be transmitted from the housing 3 as the drive shaft to the inner shaft 9 as the driven shaft.

  Therefore, during stable running after starting, torque can be transmitted between the drive shaft and the driven shaft by the differential between the drive shaft and the driven shaft. Further, since the motor 7 acts as a generator, not only electricity consumption can be suppressed, but charging can be performed, and consumption of the storage battery can be prevented.

  Next, switching between the motor mode and the generator mode of the motor 7 will be described with reference to the block diagram of FIG.

  First, according to the movement of the vehicle, the CPU executes a torque distribution program at minute time intervals, takes in various signals from the wheel speed sensors Sfl, Sfr, Srl, Srr, and the throttle sensor Sth, and based on each sensor signal. The vehicle speed V, the throttle opening θ, and the differential rotational speed ΔN are calculated and read (step 102). That is, the vehicle speed V is calculated based on the average value of the wheel speeds of the driven wheels Wrl and Wrr detected by the wheel speed sensors Srl and Srr. The housing 3 as the drive shaft and the inner shaft as the driven shaft based on the average value of the wheel speeds of the driving wheels Wfl and Wfr detected by the wheel speed sensors Sfl and Sfr and the average value of the wheel speeds of the driven wheels Wrl and Wrr. 9 is calculated, and the throttle opening θ is calculated based on the throttle signal from the throttle sensor Sth.

  Next, the necessary torque T transmitted from the drive shaft to the driven shaft is calculated as follows. For example, the pre-torque T1 corresponding to the vehicle speed V and the throttle opening θ is read from the torque map MT as shown in FIG. 6, and the correction corresponding to the differential rotational speed is corrected from the correction torque map MT2 as shown in FIG. The torque T2 is read, the torques T1 and T2 are added, and the necessary torque T is calculated (step 104).

  Next, it is determined whether or not the vehicle speed is 20 km / h or more (step 106). If the vehicle speed calculated based on the wheel speeds detected by the wheel speed sensors Srl, Srr is 20 km / h or more, the mode shifts to the generator mode, and if it is less than 20 km / h, the mode shifts to the determination of the differential rotational speed ΔN. (Step 108). In this way, the determination based on the vehicle speed is performed in advance because it is generally considered that the differential rotational speed ΔN between the drive shaft and the driven shaft is smaller than the slip state of the wheels during low speed traveling. In addition, if the vehicle speed is not higher than a certain speed, it may be difficult to function as a generator.

  In step 108, it is determined whether or not the differential rotational speed ΔN is less than 50 rpm. If the differential rotational speed ΔN is less than 50 rpm, the necessary regenerative current cannot be obtained and the motor mode is switched (step 120). Next, a target current value A1 is determined according to the necessary torque T (step 122). This is a current value that causes the motor 7 to produce a driving torque necessary to generate the necessary torque T in the motor mode. This required torque T is not directly generated by the torque of the motor 7, but is a torque transmitted from the drive shaft to the driven shaft that is changed by the pressing force with which the clutch 20 is engaged by the cam mechanism 21. Therefore, the target current value A1 is a current value necessary for causing the motor 7 to generate a driving torque for controlling the clutch 20 to be pressed. This is determined by reading in advance from a map (not shown) representing the relationship between the required torque T and the required current value. Then, the drive torque output from the motor 7 is controlled by the target current value A1 so as to generate the necessary torque T (step 124). Then, the current control circuit 37 causes the current of the target current value A1 to flow through the motor 7 so that the clutch plates 18 and 19 are engaged and the torque (necessary torque T) to be transmitted between the drive shaft and the driven shaft is obtained. Can communicate. Therefore, the transmission response of the necessary torque T can be performed without delay by setting the motor mode when starting or running at a low speed.

  On the other hand, when the vehicle speed is 20 km / h or more, or when the differential rotation speed ΔN is 50 rpm or more, the mode is switched to the generator mode (step 110). In this case, the target current value A2 is determined (step 112). This target current value A2 is a current value generated by power generation when the motor 7 is used as a regenerative brake to generate counter torque in the generator mode, and the counter torque presses the clutch 20 by the cam mechanism 21, and the necessary current is generated. It is a current value for determining whether the value is sufficient to generate the torque T. This is also read in advance from a map (not shown) representing the relationship between the generated current value, the counter torque and the necessary torque T.

  Next, the current value generated by the motor 7 as a generator is detected by the generated current measuring sensor Se (step 114). Then, the detected generated current value is compared with the target current value A2 (step 116). If the generated current value is less than the target current value A2, the mode is switched to the motor mode. This is because the counter-torque that generates the necessary torque T is not generated. If the generated current value is equal to or greater than the target current value A2, the generated current is controlled by charging the surplus current or using a variable resistor so that the target current value A2 is reached (step 118). These controls are repeatedly executed at a certain cycle by the monitoring program.

  Therefore, in the case of a certain high-speed driving state, the generator mode and the motor mode are switched according to the vehicle speed, the differential rotation speed ΔN and the generated current value. Necessary torque can be transmitted. Furthermore, since it is not necessary to continue the flow of current in order to transmit the torque, it is possible to suppress current consumption, and in addition, since it can be charged by acting as a generator, it is possible to prevent consumption of the storage battery.

  In this embodiment, the differential gear is a planetary gear mechanism composed of a sun gear, a planetary gear, a carrier, and a ring gear. However, the present invention is not limited to this, and any device / mechanism that generates a differential can be used. it can.

  As for the planetary gear mechanism, various planetary gear mechanisms such as a double pinion can be used.

The conceptual diagram which used the driving force transmission device for the four-wheel drive vehicle. The block diagram of a control apparatus. Sectional drawing of the drive force transmission device. The speed diagram of the planetary gear mechanism in the stable running state of the vehicle. The block diagram which shows control of a motor. The figure which shows an example of a torque map. The figure which shows an example of a correction torque map.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device, 3 ... Housing (drive shaft), 7 ... Motor, O ... Rotation axis, 8 ... Drive gear (reduction gear), 9 ... Inner shaft (driven shaft), PGM1 ... 1st planetary gear mechanism, PGM2 ... second planetary gear mechanism, R1, R2 ... first and second ring gears (third rotating shaft), S1 ... first sun gear (second rotating shaft), S2 ... first cam member (second sun gear-first Rotating shaft), P1, P2 ... Planetary gears, C1, C2 ... First and second carriers, 18 ... Outer clutch plate, 19 ... Inner clutch plate, 22 ... Second cam member.

Claims (4)

Provided between the drive shaft and the driven shaft, with respect to the outer clutch or the inner clutch is movable relative rotation in a direction parallel to the axis of rotation restricting the driven shaft relative to the drive shaft A clutch composed of an inner clutch or an outer clutch provided to restrict relative rotation and move in a direction parallel to the rotation axis;
The by movable second cam member of the cam mechanism provided, rotating the second cam member relative to restrict relative rotation to the rotation axis and the direction parallel to the drive shaft to the drive shaft In the driving force transmission device including the first cam member of the cam mechanism for relatively moving the second cam member in the rotation axis direction,
A first rotary shaft connected through said first cam member and said second cam member to said drive shaft, a second rotating shaft connected the driven shaft, and a third rotating shaft connected to a motor A differential having
The differential device at the time of the motor drive, transmitted to the first cam member to convey the torque of the motor to the first rotation shaft via the second rotation axis from said third axis of rotation, said first 1 and amplifies the torque of the motor by a relative movement of the second cam member is pressed against said clutch,
When the motor is not driven, the motor is rotated by rotating the third rotating shaft by a differential based on the difference in the number of rotations generated between the driving shaft and the driven shaft. In addition to generating torque, the counter torque is transmitted from the third rotating shaft to the first rotating shaft via the second rotating shaft, thereby transmitting the torque to the first cam member, and the first and second cam members. A driving force transmission device that presses the clutch by relative movement of each other .
  The driving force transmission device according to claim 1, wherein the differential device is a planetary gear mechanism.   3. The driving force transmission device according to claim 1, wherein a speed reduction device is provided between the motor and the third rotating shaft. An inner shaft that is rotatably supported on the same rotation axis on a housing that is rotatably supported by a differential case, a clutch storage chamber that is formed between the inner periphery of the housing and the outer periphery of the inner shaft, An outer clutch plate that is engaged with an engagement portion formed on a peripheral surface so as to be able to move in a direction parallel to the rotation axis while restricting relative rotation, and an outer periphery of the inner shaft that are alternately arranged with the outer clutch plate An inner clutch plate that is engaged with the surface so as to be able to move in a direction parallel to the rotation axis by restricting relative rotation, and a rotation axis that restricts relative rotation to an engagement portion formed on the inner peripheral surface of the housing. A second cam member engaged so as to be movable in a parallel direction and an outer periphery of the inner shaft are loosely fitted to the second cam member via the cam floor. A first cam member connected to the second cam member, the second cam member being constituted by the outer clutch plate and the inner clutch plate and generated in response to relative rotation between the first cam member and the second cam member. In the driving force transmission device that presses the outer clutch plate and the inner clutch plate by axial movement,
A first sun gear externally fitted to the inner shaft so as not to move relative to the inner shaft; a first ring gear having outer teeth formed on the outer periphery; and a first carrier that rotates in conjunction with the rotation of the first sun gear and the first ring gear. A first planetary gear mechanism having:
A drive shaft rotatably connected to external teeth of the first ring gear and fixed to the differential case;
A second sun gear integrally formed with the first cam member, a second ring gear provided in the differential case so as not to move relative to the differential case, and the second sun gear connected to the first carrier so as not to move relatively; And a second planetary gear mechanism having a second carrier that rotates in conjunction with the rotation of the second ring gear.

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