JP4910587B2 - Driving force distribution device - Google Patents

Description

  The present invention relates to a driving force distribution device capable of controlling a distribution ratio of driving force input from a driving source to first and second output shafts.

  Conventionally, a differential mechanism that transmits an input driving force to first and second output shafts while allowing mutual differential, and a planetary gear mechanism that is interposed between the first and second output shafts. And a motor connected to the planetary gear mechanism, and a driving force distribution device capable of varying the driving force distribution between the first and second output shafts by controlling the motor rotation direction and the motor torque. .

  For example, in Patent Document 1, a planetary gear mechanism U1 as shown in FIG. 14 is interposed between left and right axles provided differentially rotatable via a rear differential, that is, between first and second output shafts. Thus, there is disclosed a driving force distribution device capable of controlling the distribution ratio of the driving force of the engine to the left and right driving wheels.

  In this driving force distribution device, the planetary gear mechanism U1 includes a double-pinion planetary gear PG formed by connecting pinion gears coaxially arranged so as to be integrally rotatable, and two sun gears SG1 and SG2 meshing with the respective pinions. The planetary gear PG is configured to include a planetary carrier C that supports the planetary gear PG so that it can rotate and revolve. In this planetary gear mechanism U1, when both the sun gears SG1 and SG2 are rotated with the planetary carrier C fixed, the second sun gear SG2 (the right side in the figure) is more than the first sun gear SG1 (the right side in the figure). The middle left) has a higher rotational speed, that is, the first sun gear SG1 is a reduction gear and the second sun gear SG2 is a speed increase gear. In this driving force distribution device, a right axle is connected to the sun gear SG1 via a differential, and a left axle is connected to the other sun gear SG2 via a speed change mechanism. A motor as a control drive source for driving the planetary gear mechanism U1 is drivingly connected to the planetary carrier C.

That is, the driving force distribution device rotates the planetary carrier C based on the motor torque, so that the first sun gear SG1 side is changed to the second sun gear SG2 side or the second sun gear SG2 side is changed to the first sun gear SG1 side. Torque can be transmitted to the side. That is, by driving the planetary gear mechanism U1 with the planetary carrier C as an input element of control torque, the driving force (torque) transmitted to the left and right axles is apparently from the right axle side to the left axle side. Or from the left axle side to the right axle side. By controlling the motor rotation direction and the motor torque, it is possible to vary the driving force distribution for the left and right axles.
JP 2006-112474 A

  However, in the planetary gear mechanism, the relationship between the setting of the input element of the control torque, the torque transmission direction, the rotational speed of each gear meshing with the planetary gear, and the rotational speed of the planetary carrier that supports the planetary gear is predetermined. When it is below, the torque transmission characteristic is changed.

  For example, in the planetary gear mechanism U1 shown in FIG. 14, when the planetary carrier C is used as an input element for the control torque, torque is transmitted from the second sun gear SG2 on the speed increasing side to the first sun gear SG1 on the speed reducing side. The state where the rotational speed of the first sun gear SG1 is higher than the rotational speed of the planetary carrier C corresponds to the predetermined condition. When this condition is satisfied, the torque amount transmitted from the speed-increasing second sun gear SG2 to the speed-reducing first sun gear SG1 with respect to an input of a constant control torque is other than this condition. It is characterized by a large increase compared to the case.

  For this reason, in the conventional driving force distribution device (right and left driving force distribution device) using the planetary gear mechanism having the same configuration as this, as shown in FIG. 15, the motor torque input to the planetary gear mechanism as control torque is used. Even if it is constant, depending on the rotational speeds of the left and right drive wheels, the difference in transmission torque between the two drive wheels will be larger than the target value. That is, there is a problem that the left and right driving force distribution (torque difference) fluctuates depending on the traveling state such as the vehicle speed, the turning direction and the turning radius, and this is a factor that impairs the steering feeling. It left room for improvement.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a driving force distribution device that enables more accurate driving force distribution.

  In order to solve the above problems, the invention according to claim 1 is characterized in that a differential mechanism that transmits an input driving force to the first and second output shafts while allowing mutual differential, and the first A planetary gear mechanism interposed between the first and second output shafts, a motor drivingly connected to the planetary gear mechanism, and a motor rotation direction and a motor torque to control the first and second output shafts. And a control means for controlling the driving force distribution of the driving power distribution apparatus, wherein the control means compensates for fluctuations in the driving force distribution between the two output shafts due to a change in torque transmission characteristics of the planetary gear mechanism. Therefore, the gist is to correct the motor torque.

  In other words, the planetary gear mechanism has a characteristic that its torque transmission characteristic changes depending on the use situation. However, as described above, by correcting the motor torque that is input to the planetary gear mechanism as a control torque under a predetermined condition, it is possible to compensate for fluctuations in the driving force distribution caused by such changes in torque transmission characteristics. This makes it possible to accurately distribute the driving force.

  According to a second aspect of the present invention, the control means includes, among the components of the planetary gear mechanism, the rotational speed of the planetary carrier that supports the planetary gear so that it can rotate and revolve, and the rotational speed of the gear meshed with the planetary gear. Based on this comparison, the gist is to correct the motor torque.

  That is, the torque transmission characteristic change in the planetary gear mechanism depends on the relationship between the rotational speed of the planetary carrier, which is a component thereof, and the rotational speed of the gear meshing with the planetary gear. Therefore, by correcting the motor torque based on the comparison between the rotation speed of the planetary carrier and the rotation speed of the meshing gear, it is possible to accurately compensate for fluctuations in driving force distribution caused by changes in torque transmission characteristics. .

  The invention according to claim 3 is that the two gears meshed with the planetary gear among the constituent elements of the planetary gear mechanism have both external teeth or both internal teeth, and the motor has the planetary gear. Is connected to a planetary carrier that supports the planetary carrier so as to be capable of rotating and revolving, and is engaged with the planetary gear as a first detection means for detecting the rotation speed of the planetary carrier as a first rotation speed. And a second detecting means for detecting the rotational speed of the gear, wherein the control means changes from the speed increasing side gear on the speed increasing side to the speed reducing side gear on the speed reducing side when the planetary carrier is fixed. When the second rotational speed is faster than the first rotational speed in a state where torque is transmitted, correction for reducing the motor torque is performed. The gist.

  According to a fourth aspect of the present invention, of the components of the planetary gear mechanism, two gears meshed with the planetary gear have both external teeth or both internal teeth, and the motor Of the two gears meshed with the planetary gear, when the planetary carrier that supports the planetary gear so as to rotate and revolve is fixed, the first gear is driven and connected to the speed-up side gear that becomes the speed-up side. The control means includes first detection means for detecting the rotation speed of the planetary carrier as a rotation speed, and second detection means for detecting the rotation speed of the gear meshed with the planetary gear as a second rotation speed, In the state where torque is transmitted from the planetary carrier to the reduction gear which is the deceleration side when the planetary carrier is fixed, the first carrier If the than the rotational speed second rotational speed is high, by correcting to increase the motor torque, and the gist.

  The invention according to claim 5 is that, among the components of the planetary gear mechanism, two gears meshed with the planetary gear are one in which one has external teeth and the other has internal teeth, Of the two gears meshed with the planetary gear, the planetary carrier that supports the planetary gear so as to be capable of rotating and revolving is fixedly connected to the speed increasing side gear that is the speed increasing side, The control means comprises: first detection means for detecting the rotation speed of the planetary carrier as one rotation speed; and second detection means for detecting the rotation speed of the gear meshed with the planetary gear as the second rotation speed. In the state where torque is transmitted from the reduction gear on the deceleration side to the planetary carrier when the planetary carrier is fixed. When the rotational speed of the speed-increasing gear detected as the second rotational speed is faster than, or when the rotational speed of the deceleration-side gear detected as the second rotational speed is slower than the first rotational speed The gist is to perform correction to reduce the motor torque.

  The invention according to claim 6 is that, among the components of the planetary gear mechanism, two gears meshed with the planetary gear are one in which one has external teeth and the other has internal teeth, Of the two gears engaged with the planetary gear, when the planetary carrier that supports the planetary gear so as to be capable of rotating and revolving is fixed, the first rotation A first detecting means for detecting the rotational speed of the planetary carrier as a speed; and a second detecting means for detecting the rotational speed of a gear meshed with the planetary gear as a second rotational speed, the control means comprising: When the planetary carrier is fixed, the first rotational speed is transmitted in a state where torque is transmitted from the speed increasing side gear which is the speed increasing side to the planetary carrier. When the rotational speed of the speed-increasing gear detected as the second rotational speed is faster than, or when the rotational speed of the deceleration-side gear detected as the second rotational speed is slower than the first rotational speed The gist of the present invention is to perform correction to increase the motor torque.

  As in each of the above configurations, by optimizing according to the structure of the planetary gear mechanism and the input element of the control torque, the fluctuation of the driving force distribution caused by the change in torque transmission characteristics can be more accurately performed. Can be compensated.

  ADVANTAGE OF THE INVENTION According to this invention, the driving force distribution apparatus which enables more exact driving force distribution can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the vehicle 1 is a four-wheel drive vehicle based on a front-wheel drive vehicle, and a pair of front axles 4 </ b> L and 4 </ b> R are connected to a transaxle 3 assembled beside the engine 2. The driving force of the engine 2 is transmitted to the front wheels 5L and 5R via the front axles 4L and 4R. A propeller shaft 6 is connected to the transaxle 3 together with the front axles 4L and 4R. The propeller shaft 6 is connected to a pair of rear axles 9L and 9R via a torque coupling 7 and a rear differential 8. Has been. The driving force is also transmitted to the rear wheels 10L and 10R via the propeller shaft 6, the rear differential 8, and the rear axles 9L and 9R.

  As shown in FIG. 2, the rear differential 8 of this embodiment includes a planetary gear type differential mechanism 11. Specifically, the differential mechanism 11 has a ring gear 13 formed integrally with the external gear 12, and a sun gear 14 is coaxially disposed inside the ring gear 13. Further, between the ring gear 13 and the sun gear 14, a plurality of planetary gear pairs 15 including a first planetary gear 15a and a second planetary gear 15b are interposed. Are respectively meshed with the sun gear 14. The first planetary gear 15a and the second planetary gear 15b constituting each planetary gear pair 15 are supported by the planetary carrier 16 so that they can rotate and revolve, respectively, while being engaged with each other.

  In this embodiment, a drive pinion 18 is provided at one end of the input shaft 17 connected to the propeller shaft 6 via the torque coupling 7, and the ring gear 13 is an external gear 12 formed on the outer periphery thereof. Are connected to the drive pinion 18 by being engaged with the drive pinion 18. The sun gear 14 is fixed to the shaft end of the left rear axle 9L, and the planetary carrier 16 is fixed to the shaft end of the right rear axle 9R, so that the sun gear 14 and the corresponding rear axles 9L and 9R can rotate together. .

  That is, the rotation of the propeller shaft 6 is transmitted from the torque coupling 7 and the input shaft 17 to the ring gear 13 through the drive pinion 18, and the sun gear 14 and the planetary carrier 16 rotate together with the ring gear 13. The driving force is transmitted from the rear axles 9L, 9R to the left and right rear wheels 10L, 10R. The difference in rotation that occurs between the left and right rear wheels 10L, 10R, such as when the vehicle is turning, is caused by each of the first planetary gears 15a and the second planetary gears 15b revolving around the sun gear 14 while rotating. It is an acceptable configuration.

(Driving power distribution device)
Further, the rear differential 8 of the present embodiment has a function as a driving force distribution device 20 capable of controlling the distribution ratio of the driving force of the engine 2 to the left and right rear wheels 10L, 10R.

  More specifically, in this embodiment, a planetary gear mechanism 21 is interposed between the rear axles 9L and 9R constituting the first and second output shafts of the driving force distribution device 20, and the planetary gear mechanism 21 is provided. The motor 22 is drivingly connected as a control drive source. The operation of the motor 22 is controlled by the ECU 23, and a differential rotation is generated between the rear axles 9L and 9R based on the motor torque, thereby driving the engine 2 input from the propeller shaft 6 via the drive pinion 18. The distribution ratio of the force to the rear axles 9L and 9R can be controlled.

  More specifically, the planetary gear mechanism 21 of the present embodiment has the same configuration as the planetary gear mechanism U1 shown in FIG. That is, the planetary gear mechanism 21 includes two sun gears 24 and 25 that are arranged coaxially with the left rear axle 9L, a plurality of double pinions 26 that mesh with the two sun gears 24 and 25, and each of these double pinions 26 that rotates. It is constituted by a planetary carrier 27 which is supported so that it can revolve.

  In the present embodiment, different numbers of teeth are set for the sun gears 24, 25, and different teeth are also set for the first and second pinions 26a, 26b of the double pinion 26 that mesh with the sun gears 24, 25. Number is set. When both the sun gears 24 and 25 are rotated with the planetary carrier 27 fixed, the rotation speed of the second sun gear 25 is higher than that of the first sun gear 24, that is, the planetary carrier 27 is fixed. In this case, the first sun gear 24 is configured as a reduction side gear, and the second sun gear 25 is configured as a speed increase side gear. That is, in the present embodiment, the first sun gear 24 corresponds to the first sun gear SG1 in the planetary gear mechanism U1, the second sun gear 25 corresponds to the second sun gear SG2, and the double pinion 26 corresponds to the planetary gear PG. . The planetary carrier 27 corresponds to the planetary carrier C.

  In the present embodiment, the first sun gear 24 is connected to the planetary carrier 16 of the differential mechanism 11 so as to be integrally rotatable, that is, is connected to the right rear axle 9R via the differential mechanism 11. The second sun gear 25 is connected to the left rear axle 9L via the speed change mechanism 31. The motor 22 as a control drive source is drivingly connected to a planetary carrier 27 that supports each double pinion 26.

  That is, by inputting the motor torque generated by the motor 22 to the planetary carrier 27 as a control torque, the planetary gear mechanism 21 moves from the first sun gear 24 side to the second sun gear 25 side or the second sun gear 25 side. Torque is transmitted from the first to the first sun gear 24 side. The ECU 23 controls the rotational direction of the motor 22 and the motor torque that are input as the control torque, thereby distributing the driving force in the rear axles 9L and 9R to which the first and second sun gears 24 and 25 are connected, respectively. Control.

  The transmission mechanism 31 is provided to correct the transmission ratio of the planetary gear mechanism 21 so as to suppress the rotation of the planetary carrier 27 based on the transmission ratio set in the planetary gear mechanism 21. The speed change mechanism 31 of the present embodiment is configured so that the planetary gear having the same configuration as that of the planetary gear mechanism 21 is disposed beside the planetary gear mechanism 21 by reversing the arrangement of the sun gear 34 on the reduction side and the sun gear 35 on the speed increasing side. Are arranged between the planetary gear mechanism 21 and the left rear axle 9L. That is, the speed increasing sun gear 35 in the speed change mechanism 31 is connected to the speed increasing sun gear 25 in the planetary gear mechanism 21, and the speed reducing sun gear 34 is connected to the left rear axle 9L. Then, the planetary carrier 37 that supports the planetary gear 36 is fixed to a casing (not shown) that is a non-rotating part, thereby canceling the speed ratio set in the planetary gear mechanism 21 and drivingly connected to the motor 22. The rotation of the carrier 27 when the motor is not driven can be suppressed.

Next, a mode of motor control by the ECU will be described.
As shown in FIGS. 1 and 2, in this embodiment, the steering angle θs detected by the steering sensor 38 is input to the ECU 23. Then, the ECU 23 controls the operation of the motor 22 based on the detected steering angle θs.

  That is, when the vehicle is turning, the rotational speed of the outer wheel is faster than the inner wheel in the turning radius direction. Then, the ECU 23 controls the operation of the motor 22 so that the driving force distribution of the left and right rear wheels 10L, 10R which becomes the outer driving wheel becomes large. Specifically, as shown in FIG. 3, the ECU 23 switches the rotation direction of the motor 22 in accordance with the steering direction indicated by the input steering angle θs. The amount of current supplied to the motor 22 is controlled so that the motor torque increases as the absolute value of the steering angle θs increases.

(Compensation control)
As described above, in the planetary gear mechanism, the setting of the input element of the control torque, the torque transmission direction, and the relationship between the rotational speed of each gear meshing with the planetary gear and the rotational speed of the planetary carrier supporting the planetary gear. However, when it is under a predetermined condition, the torque transmission characteristic changes. Then, like the driving force distribution device 20 of the present embodiment, a planetary gear mechanism 21 having the same configuration as the planetary gear mechanism U1 shown in FIG. 14 is used, and the planetary carrier 27 has a motor as a control drive source. In the configuration in which 22 is connected, the following problem occurs due to the change in the torque transmission characteristic.

  That is, in the state where torque is transmitted from the second sun gear 25 side (acceleration side gear) to the first sun gear 24 side (deceleration side gear) during left turn, each sun gear is more than the rotational speed of the planetary carrier 27. When the rotation speed is high, the torque transmitted from the second sun gear 25 side to the first sun gear 24 side increases even though the motor torque is constant. As a result, there arises a problem that the torque difference between the left and right rear axles 9L and 9R is larger than an assumed value.

  In consideration of this point, in the driving force distribution device 20 of the present embodiment, the ECU 23 monitors whether or not the planetary gear mechanism 21 is under such a condition that the torque transmission characteristic changes. If it is determined that the torque transmission characteristic is changing, the motor torque generated by the motor 22 is corrected to compensate for the fluctuation in the driving force distribution (torque difference) caused by the change in the torque transmission characteristic. (See FIG. 3).

  Specifically, in the present embodiment, wheel speed sensors 39L and 39R provided on the left and right rear axles 9L and 9R are connected to the ECU 23, and the ECU 23 is detected by the wheel speed sensors 39L and 39R. Based on the left and right wheel speeds V_L and V_R, the rotational speed ωG of the first sun gear 24 and the rotational speed ωC of the planetary carrier 27 are calculated. In the present embodiment, the rotational speed ωC of the planetary carrier 27 corresponds to the first rotational speed, and the rotational speed ωG of the first sun gear 24 corresponds to the second rotational speed. The ECU 23 compares these two rotational speeds ωG and ωC, and if the rotational speed ωG of the first sun gear 24 is higher than the rotational speed ωC of the planetary carrier 27, the motor 23 reduces the motor torque. The amount of current supplied to 22 is reduced.

  That is, as shown in the flowchart of FIG. 4, when the ECU 23 acquires the steering angle θs and the left and right wheel speeds V_L and V_R as the state quantities (step 101), the motor to be generated by the motor 22 based on the steering angle θs first. The torque is determined, and a command value (current command Iq *) for the amount of current supplied to the motor 22 is calculated (step 102).

  Next, the ECU 23 determines whether or not the steering angle θs is a value indicating a left turn (step 103). If the steering angle θs is a left turn (step 103: YES), the left and right wheel speeds are subsequently determined. Based on V_L and V_R, the rotational speed ωG of the first sun gear 24 and the rotational speed ωC of the planetary carrier 27 are calculated (steps 104 and 105). Then, it is determined whether or not the rotational speed ωG of the first sun gear 24 is faster than the rotational speed ωC of the planetary carrier 27 (step 106). If it is faster (ωG> ωC, step 106: YES), the motor 22 In order to reduce the motor torque generated, the correction for reducing the current command Iq * calculated in step 102 is executed (step 107).

  In this embodiment, the correction for reducing the current command Iq * in step 107 is performed by multiplying the current command Iq * calculated in step 102 by a predetermined coefficient α smaller than “1” (Iq ** = Iq * × α, α <1). When it is determined in step 103 that the vehicle is turning right (step 103: NO), or in step 106, the rotational speed ωG of the first sun gear 24 is equal to or lower than the rotational speed ωC of the planetary carrier 27. (Step 106: NO), the torque correction in step 107 is not executed. That is, power supply to the motor 22 is executed based on the current command Iq * calculated in step 102 (step 108).

As described above, according to the present embodiment, the following operations and effects can be obtained.
The ECU 23 determines whether or not the steering angle θs is a value indicating that the vehicle is turning left (step 103). If it is determined that the vehicle is turning left (step 103: YES), the left and right wheel speeds V_L are subsequently determined. , V_R, the rotational speed ωG of the first sun gear 24 and the rotational speed ωC of the planetary carrier 27 are calculated (steps 104 and 105). Then, it is determined whether or not the rotational speed ωG of the first sun gear 24 is faster than the rotational speed ωC of the planetary carrier 27 (step 106). If it is faster (ωG> ωC, step 106: YES), the motor 22 In order to reduce the motor torque generated, the correction for reducing the current command Iq * calculated in step 102 is executed (step 107).

  (1) That is, the planetary gear mechanism has a feature that its torque transmission characteristic changes depending on the use situation. However, as described above, when the motor torque input to the planetary gear mechanism 21 as the control torque is corrected under a predetermined condition, the driving force distribution (torque difference) resulting from the change in the torque transmission characteristic is corrected. ) Can be compensated for, and this enables accurate driving force distribution.

  (2) The change in the torque transmission characteristic depends on the relationship between the rotational speed ωC of the planetary carrier 37 and the rotational speed ωG of the sun gear 34 that are components of the planetary gear mechanism. Therefore, by correcting the motor torque on the basis of the comparison between the rotational speed ωC of the planetary carrier 37 and the rotational speed ωG of the sun gear 34, it is possible to accurately compensate for fluctuations in the driving force distribution caused by changes in torque transmission characteristics. Can do.

  (3) In the configuration in which the planetary gear mechanism 21 including the two sun gears 24 and 25 meshing with the planetary gear 36 is used and the motor 22 as the control drive source is connected to the planetary carrier 27, the following torque transmission characteristics Changes occur. That is, in the state where the motor 22 is controlled so that torque is transmitted from the second sun gear 25 side (acceleration side gear) to the first sun gear 24 side (deceleration side gear), the rotational speed of the planetary carrier 27 When the rotational speed ωG of the sun gear 34 is faster than ωC, the torque transmitted from the second sun gear 25 side to the first sun gear 24 side increases despite the constant motor torque. Therefore, when the rotational speed ωG of the sun gear 34 is faster than the rotational speed ωC of the planetary carrier 37, the motor torque input as the control torque is reduced, so that the fluctuation of the driving force distribution due to the change of the torque transmission characteristic is reduced. It is possible to compensate with high accuracy.

In addition, you may change this embodiment as follows.
In the present embodiment, the rotational speed of the first sun gear 24 is used as the second rotational speed, but the rotational speed of the second sun gear 25 may be used.

  In the present embodiment, the current command Iq * is corrected by multiplying the current command Iq * by a predetermined coefficient α smaller than “1”. However, the present invention is not limited to this, and other methods such as adding (subtracting) a predetermined amount to the current command Iq * or using a special map may be used.

In the present embodiment, the planetary gear type differential mechanism 11 is used, but a bevel gear type differential mechanism may be used.
In this embodiment, the present invention is a planetary gear mechanism U1 including a double pinion type planetary gear PG, two sun gears SG1 and SG2 meshing with the respective pinions, and a planetary carrier C that supports the planetary gear PG. The driving force distribution device 20 using the planetary gear mechanism 21 having the same configuration as that shown in FIG. 14 is embodied. However, the present invention is not limited to this, and a driving force distribution device using a planetary gear mechanism having another configuration may be used.

  For example, as shown in FIG. 5, the planetary gear mechanism has the same configuration as the planetary gear mechanism U2 provided with two ring gears RG1 and RG2 having internal teeth instead of the sun gears SG1 and SG2 having external teeth. Is used. The planetary gear mechanism U2 is configured such that the first ring gear RG1 side is the speed increasing side gear, and the second ring gear RG2 side is the speed reducing side gear. Then, the planetary carrier C is set as an input element for the control torque.

  Specifically, in the driving force distribution device 40 shown in FIG. 6, the planetary gear mechanism 41 having the same configuration as that of the planetary gear mechanism U2 has a speed increasing ring gear 44 corresponding to the first ring gear RG1. The left rear axle 9L is connected via the speed change mechanism 51. The second ring gear 45 on the speed reduction side corresponding to the second ring gear RG2 is connected to the right rear axle 9R via the differential mechanism 11. The motor 22 as a control drive source is drivably coupled to a planetary carrier 47 (corresponding to the planetary carrier C) that supports each double pinion 46 (corresponding to the planetary gear PG). The speed change mechanism 51 in the driving force distribution device 40 is also a planetary gear mechanism having the same configuration as that of the planetary gear mechanism 41, in which the arrangement of the ring gear 54 on the speed reduction side and the sun gear 55 on the speed increase side is reversed. The gear mechanism 41 is connected to the left rear axle 9L. The planetary carrier 57 that supports the double pinion 56 is fixed so as not to rotate with respect to a casing (not shown) that is a non-rotating member.

  With this configuration, during the same operation as the driving force distribution device 40, that is, when turning left, from the first ring gear 44 side (acceleration side gear) to the second ring gear 45 side (deceleration side gear). The motor 22 is controlled to transmit torque. When the rotational speed ωG of the ring gear 44 is higher than the rotational speed ωC of the planetary carrier 47, the first ring gear 44 side (acceleration side) is changed to the second ring gear 45 side (increased although the motor torque is constant). The torque transmitted to the deceleration side) increases. Therefore, also in the case where such a configuration is embodied, when the rotational speed ωG of the ring gear 44 is higher than the rotational speed ωC of the planetary carrier 37, the torque transmission characteristic is changed by reducing the motor torque. It is possible to accurately compensate for the fluctuations in the driving force distribution caused.

  In this embodiment, the planetary carrier 27 (C) is used as an input element for the control torque. However, the present invention is not limited to this, and the present invention corresponds to the speed-increasing gear (the second sun gear SG2 in FIG. 14 and the first ring gear RG1 in FIG. 5) of the two gears meshed with the planetary gear PG. ) May be applied to a configuration in which the motor 22 is drivingly connected as an input element of the control torque.

  Specifically, the driving force distribution device 60 shown in FIG. 7 (using the planetary gear mechanism 61 (and the transmission mechanism 62) having the same configuration as the planetary gear mechanism U1 shown in FIG. 14) and FIG. The driving force distribution device 65 (using the planetary gear mechanism 66 (and the transmission mechanism 67) having the same configuration as the planetary gear mechanism U2 shown in FIG. 5) corresponds to this.

  However, the same is true in that the motor torque input to the planetary gear mechanism 21 is corrected as a control torque to compensate for fluctuations in the driving force distribution (torque difference) caused by changes in the torque transmission characteristics. Needs to be optimized according to its configuration.

  That is, in this case (the configuration shown in FIGS. 7 and 8), the motor 22 is configured so that torque is transmitted from the planetary carrier C to the reduction gears (first sun gear SG1, second ring gear RG2) when turning left. It becomes the structure which controls. In this state, when the rotational speed ωG of the gear meshed with the planetary gear PG is higher than the rotational speed of the planetary carrier C, the change in the torque transmission characteristic causes the planetary carrier PG to change despite the constant motor torque. The torque transmitted from the carrier C to the gear on the deceleration side is reduced.

  Accordingly, as a mode of compensation control in this case, as shown in FIG. 9, the rotational speed ωG of the gear meshed with the planetary gear PG as the second rotational speed rather than the rotational speed of the planetary carrier C as the first rotational speed. Is fast, correction for increasing the motor torque generated by the motor 22 is executed.

  Specifically, as shown in the flowchart of FIG. 10, when it is determined that the torque transmission characteristic is changing under the processing of step 203 to step 206 (step 206: YES), in step 202. Correction is performed to increase the calculated current command Iq *, that is, to increase the motor torque (step 207). This makes it possible to accurately compensate for fluctuations in driving force distribution caused by changes in torque transmission characteristics.

  Note that the processing of step 201 to step 206 and step 208 is the same as the processing of step 101 to step 106 and step 108 in the flowchart shown in FIG. Further, the correction for increasing the current command Iq * can be performed, for example, by multiplying the current command Iq * by a coefficient β larger than “1” (Iq ** = Iq * × β, β> 1).

  Furthermore, as shown in FIG. 11, the present invention may be applied to the one using a planetary gear mechanism U3 having a configuration in which one of the two gears meshed with the planetary gear PG is a ring gear RG and the other is a sun gear SG. Good.

  More specifically, as in the driving force distribution device 70 shown in FIG. 12, a motor using the sun gear SG, which is the speed increasing side gear of the planetary gear mechanism 71 having the same configuration as the planetary gear mechanism U3, as an input element of control torque. This is what is connected to the drive 22. Further, like the driving force distribution device 75 shown in FIG. 13, the ring gear RG, which is a reduction gear of the planetary gear mechanism 76 having the same configuration as the planetary gear mechanism U3, is drivingly connected to the motor 22 as an input element of control torque. This is also the case. In the driving force distribution devices 70 and 75, the speed change mechanisms 72 and 77 are similar to the speed change mechanisms 31, 51, 62, and 67 described above, and the elements of the corresponding planetary gear mechanisms 71 and 76 are the same. It is formed by reversing the arrangement.

  Here, each of the driving force distribution devices 70 and 75 shown in these drawings is also input to the planetary gear mechanism 21 as a control torque so as to compensate for fluctuations in the driving force distribution (torque difference) caused by changes in torque transmission characteristics. The same applies to the correction of the motor torque, but the control content needs to be optimized according to the configuration.

  That is, in the planetary gear mechanism U3 shown in FIG. 11, in a situation where torque transmission is performed from the ring gear RG, which is the reduction gear, to the planetary carrier C using the sun gear SG, which is the acceleration side gear, as an input element of the control torque. Torque transfer characteristics may change. This is a phenomenon that can occur when turning right in the driving force distribution device 70 shown in FIG.

  Specifically, when the speed-increasing side gear as the second rotational speed, that is, the rotational speed of the sun gear SG is faster than the rotational speed of the planetary carrier C as the first rotational speed, or the rotational speed of the planetary carrier C This corresponds to the case where the speed of the reduction gear as the second rotational speed, that is, the rotational speed of the ring gear RG is slow. Under such conditions, due to the change in the torque transmission characteristics, the motor torque input as the control torque is constant, but is transmitted from the reduction gear, that is, the ring gear RG to the planetary carrier C. Torque increases. Therefore, in the driving force distribution device 70 shown in FIG. 12, correction may be made so as to reduce the motor torque under the above conditions. Thereby, it is possible to accurately compensate for fluctuations in the driving force distribution caused by changes in the torque transmission characteristics.

  Also, the planetary gear mechanism U3 has its torque transmission even in a situation where torque transmission is performed from the sun gear SG, which is the speed increasing side gear, to the planetary carrier C using the ring gear RG, which is the speed reducing side gear, as an input element of the control torque. The characteristic is that the characteristics may change. This is a phenomenon that can occur when turning left in the driving force distribution device 75 shown in FIG.

  Specifically, as in the previous example, the speed-up side gear as the second rotational speed, that is, the rotational speed of the sun gear SG is faster than the rotational speed of the planetary carrier C as the first rotational speed, or the planetary carrier C This corresponds to the case where the rotation speed of the reduction gear as the second rotation speed, that is, the ring gear RG, is lower than the rotation speed of the carrier C. Under such conditions, due to the change in the torque transmission characteristics, the motor torque input as the control torque is transmitted from the sun gear SG, which is the speed increasing side gear, to the planetary carrier C, despite being constant. Torque decreases. Therefore, in the driving force distribution device 75 shown in FIG. 13, it is preferable to correct the motor torque so as to increase under the above conditions. Thereby, it is possible to accurately compensate for fluctuations in the driving force distribution caused by changes in the torque transmission characteristics.

  -In this embodiment, although this invention was applied to the driving force distribution apparatus with respect to the driving wheel of a vehicle left and right, you may apply to the driving force distribution apparatus with respect to the driving wheel before and behind a vehicle.

The schematic block diagram of the vehicle of this embodiment. The schematic block diagram of the driving force distribution apparatus of this embodiment. Explanatory drawing which shows the aspect of the compensation control of this embodiment. The flowchart which shows the process sequence of compensation control of this embodiment. The schematic diagram which shows schematic structure of a planetary gear mechanism. The schematic block diagram of the driving force distribution apparatus of another example. The schematic block diagram of the driving force distribution apparatus of another example. The schematic block diagram of the driving force distribution apparatus of another example. Explanatory drawing which shows the aspect of compensation control of another example. The flowchart which shows the process sequence of compensation control of another example. The schematic diagram which shows schematic structure of a planetary gear mechanism. The schematic block diagram of the driving force distribution apparatus of another example. The schematic block diagram of the driving force distribution apparatus of another example. The schematic diagram which shows schematic structure of a planetary gear mechanism. Explanatory drawing which shows the fluctuation | variation of the driving force distribution resulting from the change of a torque transmission characteristic.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Engine, 8 ... Rear differential, 9L, 9R ... Rear axle, 10L, 10R ... Rear wheel, 11 ... Differential mechanism, 20, 40, 60, 65, 70, 75 ... Driving force distribution apparatus, 21 , 41, 61, 66, 71, 76 ... planetary gear mechanism, 22 ... motor, 23 ... ECU, SG ... sun gear, SG1, 24 ... first sun gear, SG2, 25 ... second sun gear, PG ... planetary gear, 26 46, double pinion, C, 27, 47 ... planetary carrier, RG ... ring gear, RG1, 44 ... first ring gear, RG2, 45 ... second ring gear, ωC, ωG ... rotational speed.

Claims (6)

A differential mechanism for transmitting an input driving force to the first and second output shafts while allowing mutual differential; a planetary gear mechanism interposed between the first and second output shafts; In a driving force distribution apparatus comprising: a motor drivingly connected to a planetary gear mechanism; and a control means for controlling the driving force distribution between the first and second output shafts by controlling the motor rotation direction and the motor torque. ,
The control means corrects the motor torque to compensate for fluctuations in driving force distribution between both output shafts due to a change in torque transmission characteristics of the planetary gear mechanism;
A driving force distribution device characterized by the above. The driving force distribution device according to claim 1,
The control means includes the motor torque based on a comparison between a rotational speed of a planetary carrier that supports a planetary gear so that the planetary gear can rotate and revolve, and a rotational speed of a gear meshed with the planetary gear. To correct
A driving force distribution device characterized by the above. The driving force distribution device according to claim 1,
Of the components of the planetary gear mechanism, two gears meshed with the planetary gear both have external teeth or both have internal teeth, and the motor supports the planetary gear so that it can rotate and revolve. Drive coupled to the planetary carrier,
First detection means for detecting a rotation speed of the planetary carrier as a first rotation speed;
Second detection means for detecting a rotation speed of a gear meshed with the planetary gear as a second rotation speed;
When the planetary carrier is fixed, the control means is configured to transmit the torque from the speed increasing side gear that is the speed increasing side to the speed reducing side gear that is the speed reducing side rather than the first rotational speed. If the rotational speed is fast, perform correction to reduce the motor torque,
A driving force distribution device characterized by the above. The driving force distribution device according to claim 1,
Of the constituent elements of the planetary gear mechanism, two gears meshed with the planetary gear have both external teeth or both have internal teeth, and the motor has two gears meshed with the planetary gear. Among them, when the planetary carrier that supports the planetary gear so as to be able to rotate and revolve is fixed, it is drivingly connected to the speed increasing side gear that becomes the speed increasing side,
First detection means for detecting a rotation speed of the planetary carrier as a first rotation speed;
Second detection means for detecting a rotation speed of a gear meshed with the planetary gear as a second rotation speed;
When the second rotational speed is higher than the first rotational speed in a state where torque is transmitted from the planetary carrier to the speed reduction side gear when the planetary carrier is fixed, the control means Performing a correction to increase the motor torque,
A driving force distribution device characterized by the above. The driving force distribution device according to claim 1,
Of the components of the planetary gear mechanism, two gears meshed with the planetary gear are one having external teeth and the other having internal teeth, and the motor has two gears meshed with the planetary gear. Among them, when the planetary carrier that supports the planetary gear so as to be capable of rotating and revolving is fixed, it is drivingly connected to the speed increasing side gear that becomes the speed increasing side,
First detection means for detecting a rotation speed of the planetary carrier as a first rotation speed;
Second detection means for detecting a rotation speed of a gear meshed with the planetary gear as a second rotation speed;
When the planetary carrier is fixed, the control means is detected as the second rotational speed rather than the first rotational speed in a state in which torque is transmitted from the speed reduction gear on the speed reduction side to the planetary carrier. When the rotational speed of the speed increasing gear is high, or when the rotational speed of the speed reducing gear detected as the second rotational speed is slower than the first rotational speed, correction for reducing the motor torque is performed. A driving force distribution device characterized in that: The driving force distribution device according to claim 1,
Of the components of the planetary gear mechanism, two gears meshed with the planetary gear are one having external teeth and the other having internal teeth, and the motor has two gears meshed with the planetary gear. Among them, when the planetary carrier that supports the planetary gear so as to be capable of rotating and revolving is fixed, it is drivingly connected to a reduction gear that becomes a reduction side,
First detection means for detecting a rotation speed of the planetary carrier as a first rotation speed;
Second detection means for detecting a rotation speed of a gear meshed with the planetary gear as a second rotation speed;
The control means detects the second rotational speed rather than the first rotational speed in a state in which torque is transmitted from the speed-increasing gear serving as the speed increasing side to the planetary carrier when the planetary carrier is fixed. The motor torque is increased when the rotational speed of the increased speed side gear is high, or when the rotational speed of the reduction side gear detected as the second rotational speed is slower than the first rotational speed. A driving force distribution device characterized by performing correction.

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