JP2018105325A - Abnormality detection device for right and left wheel driving device, abnormality detection method and vehicle with this abnormality detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality detection device for right and left wheel driving devices capable of detecting abnormality at a gear of a gear device from beginning of occurrence of abnormality in a precise manner, an abnormality detection method and a vehicle with this abnormality detection device.SOLUTION: An abnormality detection device 68 for right and left wheel driving devices comprises two electric motors that are installed at a vehicle and can be controlled independently; and a speed reducer that is installed between these electric motors and the right and left driving wheels, amplifies a difference of torques given by said two electric motors and transmits it to each of said right and left driving wheels. An abnormality detection device 68 comprises a rotation speed difference calculating means 74 and a judgement means 76. The rotation speed difference calculating means 74 calculates a rotational speed difference between the right and left driving wheels. The judgement means 76 judges whether or not the calculated rotational speed difference becomes more than threshold periodically. When the rotational speed difference becomes more than threshold periodically, the judgement means 76 judges that abnormality is generated at the gear device.SELECTED DRAWING: Figure 7

Description

  The present invention includes an abnormality detection device, an abnormality detection method, and an abnormality detection device for a left and right wheel drive device that amplifies a torque difference and transmits drive torque generated from two independent drive sources to left and right drive wheels. Regarding vehicles.

  When it is effective to generate a large driving torque difference between the left and right drive wheels in order to achieve smooth turning of the vehicle or to suppress changes in vehicle behavior such as extreme understeer or extreme oversteer There is. Therefore, a left and right wheel drive device is disclosed that includes a gear device in which two planetary gear mechanisms are combined between two drive sources and left and right drive wheels, and amplifies the difference in torque (Patent Documents 1 and 2). ). The planetary gear mechanism of the gear device has a function of amplifying the torque difference between the two drive sources and transmitting the amplified torque difference to the left and right drive wheels and absorbing the rotational speed difference between the left and right drive wheels.

  A differential gear device is widely known as a mechanism for absorbing a difference in rotational speed between the left and right drive wheels. The differential gear device transmits the torque generated by the drive source to the left and right drive wheels. However, if an abnormality occurs in the gear teeth, the torque cannot be transmitted. In the worst case, the vehicle travels. there is a possibility. For this reason, a technique for detecting an abnormality in gear teeth at an early stage is disclosed (Patent Document 3). In Patent Document 3, the difference between the rotational speed of the driving wheel and the rotational speed of the driven wheel is calculated, and it is determined that an abnormality has occurred when the rotational speed difference periodically exceeds a specified value.

JP 2015-21594 A Japanese Patent No. 4907390 JP 2011-149508 A

  When an abnormality occurs in the gear teeth in the differential gear device, the torque of the power source may not be transmitted to the left and right drive wheels, and a so-called torque loss state may occur. On the other hand, in the left and right wheel drive device, for example, when an abnormality occurs in the teeth of the ring gear of one planetary gear mechanism, only the torque of one drive source is not transmitted, and the torque difference from the other drive source becomes a gear difference. It is amplified by the device and transmitted to the left and right drive wheels. Similarly, in the other gears, if an abnormality occurs in the gears and torque is not transmitted, a torque difference is generated between the left and right drive wheels.

  In Patent Document 3, the abnormality of the gear is detected from the difference in rotational speed between the driving wheel and the driven wheel. However, when the technique of Patent Document 3 is applied to the left and right wheel driving device, there is a possibility that a difference in detection sensitivity occurs between the left and right. There is. In addition, since the difference in rotational speed between the driving wheel and the driven wheel is small at the initial stage of occurrence of the abnormality, it is difficult to accurately detect the abnormality of the gear.

  An object of the present invention is to provide an abnormality detection device, an abnormality detection method for a left and right wheel drive device that can accurately detect an abnormality in a gear of a gear device from the initial stage of the occurrence of the abnormality, and a vehicle including the abnormality detection device. It is.

The abnormality detection device 68 of the left and right wheel drive device 1 of the present invention includes two drive sources 2L and 2R that are mounted on a vehicle and can be controlled independently, these two drive sources 2L and 2R, and left and right drive wheels 61L and 61R. And left and right wheel drive devices provided with reduction gears 3L and 3R for amplifying a difference in torque applied from the two drive sources 2L and 2R and transmitting the difference to the left and right drive wheels 61L and 61R, respectively. In the abnormality detection device of
The reduction gears 3L and 3R include a gear device 30 having two planetary gear mechanisms 30L and 30R,
The abnormality detection device 68 includes:
A rotational speed difference calculating means 74 for calculating a rotational speed difference between the left and right drive wheels 61L, 61R;
Determining means 76 for determining whether or not an abnormality has occurred in the gear device 30 based on the rotational speed difference calculated by the rotational speed difference calculating means 74.

  According to this configuration, the rotational speed difference calculating means 74 calculates the rotational speed difference between the left and right drive wheels 61L and 61R. The determination unit 76 determines whether or not an abnormality has occurred in the gear device 30 based on the calculated rotational speed difference. When an abnormality has occurred in the gear device 30, even if the two drive sources 2L and 2R output equal magnitude torque, the left and right drive wheels 61L and 61R have a period according to the abnormal part of the gear. Torque difference occurs. For this reason, the torque of one drive wheel 61L (61R) increases periodically, and the torque of the other drive wheel 61R (61L) decreases periodically. Therefore, the rotational speed of the drive wheels periodically changes in opposite directions between the left and right drive wheels 61L and 61R. Therefore, by calculating the difference in rotational speed between the left and right drive wheels 61L and 61R, it is possible to further emphasize the change in rotational speed of the drive wheels 61L and 61R. Therefore, the abnormality can be detected with high accuracy even in the initial stage of occurrence of the abnormality of the gear of the gear device 30.

Compensation means 75 for correcting the rotational speed difference using a reference rotational speed difference as a reference is provided, and the determination means 76 uses the rotational speed difference corrected by the correction means 75 to cause an abnormality in the gear device 30. It may be determined whether or not the above has occurred.
The reference rotational speed difference in the correcting means 75 may be a value based on the rotational speed difference between the left and right driven wheels 62L and 62R in the vehicle.
In this case, the correction means 75 corrects the rotational speed difference between the left and right drive wheels 61L and 61R using a reference rotational speed difference that is a value based on the rotational speed difference between the left and right driven wheels 62L and 62R. As the reference rotational speed difference, a value based on the rotational speed difference between the left and right driven wheels 62L and 62R, which has substantially no periodic rotational speed change, is employed. By correcting the rotational speed difference between the left and right drive wheels 61L and 61R using such a reference rotational speed difference, it is possible to correct the influence on the rotational speed difference due to turning or the like. Thereby, the abnormality can be detected with high accuracy from the initial stage of occurrence of the abnormality of the gear of the gear device 30.

  The correction means 75 may calculate a rotational speed difference at the drive wheel position from the left and right rotational speeds of the driven wheels 62L and 62R, and the rotational speed difference at the drive wheel position may be used as the reference rotational speed difference. In this case, the influence due to the difference in wheel position can be reduced, and the abnormality of the gear device 30 can be detected with higher accuracy.

  The reference rotational speed difference in the correcting means 75 may be a value based on the rotational speed difference between the left and right drive wheels 61L and 61R calculated from the vehicle model Md using at least the vehicle speed and the steering wheel angle. As the vehicle model Md, a planar two-degree-of-freedom model or the like can be applied. According to this configuration, by obtaining the reference rotational speed difference using the vehicle model Md, it is possible to reduce the influence due to the difference in wheel position. Therefore, the abnormality of the gear device 30 can be detected with higher accuracy.

The determination unit 76 may determine that an abnormality has occurred in the previous gear unit 30 when the rotation speed difference calculated by the previous rotation speed difference calculation unit 74 periodically exceeds a threshold value.
The threshold value is a threshold value arbitrarily determined by design or the like, and is determined by obtaining an appropriate threshold value by one or both of testing and simulation, for example.

  The control device 67 for controlling the drive sources 2L and 2R may be provided, and the control device 67 may be provided with output limiting means 79 for limiting the outputs of the drive sources 2L and 2R after the abnormality is detected by the determination means 76. In this case, it is possible to prevent the vehicle from being obstructed.

The abnormality detection method of the left and right wheel drive device of the present invention is an abnormality detection method using the abnormality detection device of the left and right wheel drive device according to any one of the above,
A rotational speed difference calculating step for calculating a rotational speed difference between the left and right drive wheels 61L, 61R;
A determination step of determining whether or not an abnormality has occurred in the gear device 30 based on the rotation speed difference calculated in the rotation speed difference calculation step.
According to this configuration, in the rotational speed difference calculating step, the rotational speed difference between the left and right drive wheels 61L and 61R is calculated. Next, in a determination step, it is determined whether or not an abnormality has occurred in the gear device 30 based on the output rotational speed difference. Thus, by calculating the difference in rotational speed between the left and right drive wheels 61L and 61R, it is possible to further emphasize the change in rotational speed of the drive wheels 61L and 61R. Therefore, the abnormality can be detected with high accuracy even in the initial stage of occurrence of the abnormality of the gear of the gear device 30.

  The vehicle according to the present invention includes the abnormality detection device 68 of any one of the left and right wheel drive devices 1. In this case, by detecting the abnormality of the gear of the gear device 30 with high accuracy from the initial stage of the occurrence of the abnormality, the vehicle can be moved to a retreat location or a repair shop by self-propelled.

  An abnormality detection device for a left and right wheel drive device according to the present invention includes two drive sources mounted on a vehicle and independently controllable, and provided between the two drive sources and the left and right drive wheels. An abnormality detection device for a left and right wheel drive device comprising: a reduction device that amplifies a difference in torque applied from a source and transmits the amplified difference to the left and right drive wheels, respectively, wherein the reduction device is a gear device having two planetary gear mechanisms. The abnormality detection device includes: a rotational speed difference calculating unit that calculates a rotational speed difference between the left and right drive wheels; and the rotational speed difference calculated by the rotational speed difference calculating unit periodically exceeds a threshold value. Determining means for determining that an abnormality has occurred in the gear device. For this reason, the abnormality of the gear of the gear device can be detected with high accuracy from the initial stage of occurrence of the abnormality.

  An abnormality detection method for a left and right wheel drive device according to the present invention is an abnormality detection method using an abnormality detection device for any one of left and right wheel drive devices, and calculates a difference in rotation speed between the left and right drive wheels. And a determination step for determining whether an abnormality has occurred in the gear device based on the rotational speed difference calculated in the rotational speed difference calculating step. Can be detected with high accuracy from the initial stage.

  Since the vehicle according to the present invention includes the abnormality detection device for any of the left and right wheel drive devices, it is possible to accurately detect an abnormality in the gears of the gear device from the beginning of the occurrence of the abnormality, and the vehicle is retracted by self-running. Or it can be moved to a repair shop.

It is a block diagram which shows the conceptual structure of the vehicle by which the abnormality detection apparatus of the left-right wheel drive device which concerns on embodiment of this invention is mounted. It is sectional drawing of the same left-right wheel drive device. It is sectional drawing which expands and shows the gear apparatus part of the left-right wheel drive device. It is a skeleton figure which shows the same right-and-left wheel drive device. It is explanatory drawing of the electric vehicle carrying the left-right wheel drive device. It is a speed diagram for demonstrating the torque difference gain by the same right-and-left wheel drive device. It is a block diagram of control systems, such as the abnormality detection apparatus. It is a flowchart of the abnormality detection performed with the abnormality detection apparatus. It is a figure which shows the example of the rotational speed of a wheel when there is abnormality in the gear of the gear apparatus. It is a figure which shows another example of the rotational speed of the wheel when there is abnormality in the gear.

  An abnormality detection device for a left and right wheel drive device according to an embodiment of the present invention will be described with reference to FIGS. The following description also includes a description of an abnormality detection method for the left and right wheel drive device. FIG. 1 is a block diagram showing a conceptual configuration of a vehicle (electric vehicle) on which the abnormality detection device for the left and right wheel drive device is mounted. This vehicle is a rear wheel drive system, and includes a chassis 60, drive wheels 61L and 61R as rear wheels, driven wheels 62L and 62R as front wheels, left and right wheel drive device 1, host ECU 66, control device 67, battery 63, and inverter. A device 64, an abnormality detection device 68, a steering angle sensor 69, rotational speed sensors 70, 71, 72, 73 and the like are provided.

  The left and right wheel drive device 1 includes first and second electric motors 2L and 2R, and left and right speed reducers 3L and 3R each having a gear device 30. The first and second electric motors 2L and 2R are two drive sources mounted on the vehicle and independently controllable. The gear device 30 is provided between the first and second electric motors 2L and 2R and the drive wheels 61L and 61R.

<Basic configuration of control system>
The host ECU 66 is a host control unit of the control device 67, and has, for example, a function of performing overall control and cooperative control of the entire vehicle and a function of generating braking / driving torque command values for the left and right drive wheels 61L and 61R. . The host ECU 66 determines the left and right braking / driving torque command values from the acceleration command output from the accelerator operation unit (not shown), the deceleration command output from the brake operation unit (not shown), and the turning command output from the steering angle sensor 69 and the like. Is generated.

  The control device 67 gives a motor torque command value to the inverter device 64 based on the left and right braking / driving torque command values given from the host ECU 66. Thus, the first and second electric motors 2L and 2R are individually controlled. The inverter device 64 converts the DC power of the battery 63 into AC power for driving the first and second electric motors 2L, 2R. The inverter device 64 controls the current supplied from the battery 63 so that the torque output from the first and second electric motors 2L and 2R is equal to the motor torque command value, and controls the first and second electric motors 2L and 2R. Drive. The output from the left and right wheel drive device 1 is transmitted to the left and right drive wheels 61L and 61R through a constant velocity joint.

<Left and right wheel drive device 1>
<< About the first and second electric motors 2L and 2R >>
In this embodiment, the first and second electric motors 2L and 2R in the left and right wheel drive device 1 use the same standard electric motors having the same maximum output.
As shown in FIG. 2, the first and second electric motors 2L and 2R include motor housings 4L and 4R, stators 6 and 6, and rotors 5 and 5, respectively. The first and second electric motors 2L and 2R are radial gap types in which the stators 6 and 6 are provided on the inner peripheral surfaces of the motor housings 4L and 4R, and the rotor 5 is provided on the inner periphery of each stator 6 at intervals. is there.

  The motor housings 4L and 4R include cylindrical motor housing bodies 4aL and 4aR, outer walls 4bL and 4bR, and inner walls 4cL and 4cR. The outer side walls 4bL and 4bR close the outer surface on the outboard side of the motor housing main bodies 4aL and 4aR. The inner side walls 4cL, 4cR are provided on the inner side surface of the motor housing main bodies 4aL, 4aR on the inboard side, and form partition walls that are separated from the reduction gears 3L, 3R. The inner walls 4cL and 4cR are provided with openings for pulling out the motor shafts 5a to the inboard side. In this specification, the side closer to the outside in the vehicle width direction of the vehicle when the left and right wheel drive device 1 is mounted on the vehicle is referred to as the outboard side, and the side closer to the center in the vehicle width direction of the vehicle is referred to as the inboard side. Called the board side.

  The stators 6 and 6 are fitted and fixed to the inner peripheral surfaces of the motor housing main bodies 4aL and 4aR. The rotor 5 has a motor shaft 5a at the center. Rolling bearings 8a and 8b are provided on the inner walls 4cL and 4cR and the outer walls 4bL and 4bR. Each motor shaft 5a is rotatably supported by motor housings 4L and 4R via rolling bearings 8a and 8b. The left and right motor shafts 5a, 5a are provided on the same axis (coaxial).

<< About the reduction gear 3 >>
The speed reduction device 3 includes left and right speed reduction devices 3L and 3R. The speed reduction devices 3L and 3R include a housing 9, input gear shafts 12L and 12R, intermediate gear shafts 13L and 13R, output gear shafts 14L and 14R, and gears. Device 30 (FIG. 3). The reduction gears 3L and 3R amplify the difference in torque (driving torque) input from the motor shaft 5a of the first and second electric motors 2L and 2R with the gear device 30 (FIG. 3), and transfer them to the driving wheels 61L and 61R. It is a device that communicates.

  The housing 9 accommodates these gear shafts and the gear device 30 (FIG. 3). The housing 9 has a structure divided into three pieces. Specifically, the housing 9 includes a central housing 9a and left and right side housings 9bL and 9bR fixed to both side surfaces of the central housing 9a. The side surface on the outboard side of the side housings 9bL and 9bR and the inner side walls 4cL and 4cR are fixed with a plurality of bolts. Thereby, the two electric motors 2L and 2R are fixed to the left and right ends of the housing 9.

  A partition wall 11 is provided in the center of the center housing 9a. The housing 9 is divided into left and right parts by the partition wall 11 and accommodates the main body portions of the left and right reduction gears 3L and 3R. The main body portion is symmetrical, and includes input gear shafts 12L and 12R, intermediate gear shafts 13L and 13R, output gear shafts 14L and 14R, and a gear device 30 (FIG. 3).

  The input gear shafts 12L and 12R have an input gear 12a to which power is transmitted from the motor shaft 5a. Rolling bearings 17a and 17b are provided in the bearing fitting holes formed in the partition wall 11 and the bearing fitting holes formed in the left and right side housings 9bL and 9bR. Both ends of the input gear shafts 12L and 12R are rotatably supported by the housing 9 via rolling bearings 17a and 17b. The input gear shafts 12L and 12R have a hollow structure. The end portions on the inboard side of the motor shafts 5a are inserted into the hollow interiors of the input gear shafts 12L and 12R. The input gear shafts 12L, 12R and the motor shafts 5a are coupled by splines (including “serration”. The following splines also include “serration”).

  As shown in FIG. 3, the left and right intermediate gear shafts 13L and 13R are arranged coaxially. The intermediate gear shafts 13L and 13R have large-diameter input-side external gears 13a and 13a that mesh with the input gears 12a and 12a, and output-side small-diameter gears 13b and 13b that mesh with output gears 14a and 14a described later. Rolling bearings 20a and 20b are provided in bearing fitting holes 19a formed in the partition wall 11 and bearing fitting holes 19b formed in the left and right side housings 9bL and 9bR. Both ends of the intermediate gear shafts 13L and 13R are rotatably supported by the housing 9 via rolling bearings 20a and 20b. The bearing fitting holes 19a and 19b have a stepped shape with which the outer ring end faces of the rolling bearings 20a and 20b come into contact, and pass through so that first and second coupling members 31 and 32, which will be described later, pass through.

  A gear device 30 is incorporated in the intermediate gear shafts 13L and 13R coaxially with the intermediate gear shafts 13L and 13R. The gear device 30 amplifies the difference in torque (drive torque) applied from the two electric motors 2L and 2R (FIG. 2). The gear device 30 includes two planetary gear mechanisms 30L and 30R having three elements and two degrees of freedom. In this example, a single pinion planetary gear mechanism is employed for the planetary gear mechanisms 30L and 30R. The two planetary gear mechanisms 30L and 30R are provided coaxially.

Planetary gear mechanism 30L, 30R is the ring gear _R L, and _{R R,} the sun gear _S L, _S and _R, the planetary gear _P L, and _{P R,} the planet carrier _C L, and _{C R,} the first, second coupling member 31 , 32. Ring gear _R L, _{R R,} an intermediate gear shaft 13L, 13R of the input-side external gear 13a, a gear inner incorporated respectively 13a. The sun gears S _L and S _R are sun gears provided coaxially with the ring gears R _L and R _R. Planetary gears _P L, _{P R} is the revolution gear meshing with the ring gear _R L, _{R R} and the sun gear _S L, _{S R.} Planet carrier _C L, _{C R} is the planetary gear _P L, is connected to the _{P R,} is provided a ring gear _R L, the _{R R} coaxially. Planet carrier _C L, the _{C R,} the intermediate gear shaft 13L, the output-side small-diameter gear 13b of the 13R, 13b are connected.

The first coupling member 31, coupling one and planet carrier C _L which is a constituent member of Figure 3 the left planetary gear mechanism 30L, the other of the sun gear S _R which is a component of the right side in FIG. 3 of the planetary gear mechanism 30R To do. The second coupling member 32 is coupled while the sun gear S _L of a component of Figure 3 the left planetary gear mechanism 30L, and the other of the planet carrier C _R is a structural member of FIG. 3 the right planetary gear mechanism 30R To do.

Planet carrier _C L, _{C R} has planetary gears _P L, a carrier pin 33 which supports the _{P R,} and the carrier flange 34a on the outboard side, and a carrier flange 34b on the inboard side. Planetary gears _P L, _{P R} is supported on a carrier pin 33 through needle roller bearings 37. The outboard carrier flange 34 a is connected to the outboard side end of the carrier pin 33. The inboard carrier flange 34 b is connected to the inboard side end of the carrier pin 33.

The carrier flange 34a on the outboard side includes a hollow shaft portion 35 extending toward the outboard side. The end portion on the outboard side of the hollow shaft portion 35 is supported by a bearing fitting hole formed in the side housings 9bL and 9bR via a rolling bearing 20b. The carrier flange 34b on the inboard side includes a hollow shaft portion 36 that extends toward the inboard side. An end portion on the inboard side of the hollow shaft portion 36 is supported in a bearing fitting hole formed in the partition wall 11 via a rolling bearing 20a. Each carrier flanges 34a, 34b outer peripheral surface and the ring gear _R L of the, between the _{R R,} the rolling bearing 39a, 39b is provided.

  The first and second coupling members 31 and 32 that connect the two planetary gear mechanisms 30L and 30R to each other are incorporated through the partition wall 11 that partitions the central housing 9a left and right. The first and second coupling members 31 and 32 are positioned coaxially with each other and are supported by the thrust bearing 47 so as to be rotatable in the axial direction and supported by the deep groove ball bearing 49 so as to be rotatable in the radial direction. Further, between the first and second coupling members 31, 32, bearings 45, 46 and a thrust bearing 48 different from the bearings 47, 49 are provided. As the other bearings 45 and 46, needle roller bearings are applied, respectively. The second coupling member 32 has a hollow shaft, and the first coupling member 31 has a shaft inserted through the hollow shaft.

And the outer circumferential surface of the right side in FIG. 3 on the outboard side, spline meshing with each other in the hollow shaft portion 36 of the carrier flange 34b on the inboard side of the planet carrier C _R are provided in the second coupling member 32. Thus, the second coupling member 32 is coupled by spline fitting to the planet carrier C _R. Therefore, the planet carrier C _R is a second rotary member rotates together with the second coupling member 32.

And the outer circumferential surface of the left side of FIG. 3 on the outboard side, spline meshing with each other in the hollow shaft portion 35 of the carrier flange 34a on the outboard side of the planet carrier C _L is provided in the first coupling member 31. Thus, the first coupling member 31 is connected by spline engagement to the planet carrier C _L. Therefore, the planet carrier C _L is a first rotating member rotates together with the first coupling member 31.

As described above, first, second coupling member 31 and 32, because it is attached by spline fitting to the planet carrier _C L, _{C R,} two planetary gear mechanisms 30L, 30R is divisible into right and left Thus, the three-piece structure housing 9 can be incorporated from the left and right together with other reduction gear shafts. End of the planet carrier C _L side of the second coupling member 32 has, on its outer circumferential surface, an external gear which constitutes the sun gear S _L in FIG. 3 the left planetary gear mechanism 30L is formed. The external gear that constitutes the sun gear S _L meshes with the planetary gear P _L.

The first coupling member 31 has a large-diameter portion 43 at the end on the planetary gear mechanism 30R side on the right side of FIG. This outer peripheral surface of the large diameter portion 43, an external gear which constitutes the sun gear S _R in FIG. 3 the right planetary gear mechanism 30R is formed. External gear constituting the sun gear S _R is engaged with the planetary gears P _R. Thrust bearings 47 and 48 are provided at both axial ends of the second coupling member 32. These thrust bearings 47 and 48, first, second coupling members 31, 32 and the planetary carrier _C L, axial movement by sliding of the spline fitting portion between _{C R} is regulated.
The first coupling member 31, the end of the right side in FIG. 3 is supported by a deep groove ball bearing 49 relative to the planet carrier C _R. An oil supply hole is provided in the axial center of the first coupling member 31.

  As shown in FIG. 2, the output gear shafts 14L and 14R have a large-diameter output gear 14a. Rolling bearings 54a and 54b are provided in the bearing fitting holes formed in the partition wall 11 and the bearing fitting holes formed in the left and right side housings 9bL and 9bR. The output gear shafts 14L and 14R are rotatably supported by the housing 9 via rolling bearings 54a and 54b.

  Outboard end portions of the output gear shafts 14L and 14R are drawn out of the housing 9 from openings formed in the side housings 9bL and 9bR. The outer joint portion of the constant velocity joint 65a is splined to the outer peripheral surface of the end portion on the outboard side of the drawn output gear shafts 14L and 14R. Each constant velocity joint 65a is connected to drive wheels 61L and 61R (FIG. 1) via an intermediate shaft (not shown).

  FIG. 4 is a skeleton diagram showing the left and right wheel drive device. FIG. 5 is an explanatory diagram of an electric vehicle equipped with the left and right wheel drive device. As shown in FIGS. 4 and 5, the left and right electric motors 2L and 2R are individually controlled by the control device 67 (FIG. 1), and can generate and output different torques.

The torque of the electric motors 2L and 2R is increased by the gear ratio between the input gear 12a of the input gear shafts 12L and 12R of the reduction gears 3L and 3R and the large-diameter input side external gear 13a of the intermediate gear shafts 13L and 13R. And transmitted to the ring gears R _L and R _R of the gear device 30. Then, the gear device 30 amplifies the difference between the left and right torques, and transmits the torque to the output-side small-diameter gear 13b. Further, the torque is further amplified by the gear ratio between the output-side small-diameter gear 13b and the output gear 14a, and is output to the drive wheels 61L and 61R.

Planetary gear mechanism 30L in gear 30, 30R, the sun gear _S L disposed coaxially, _{S R} and the ring gear _R L, and _{R R,} these sun gear _S L, _{S R} and the ring gear _R L, between the _{R R} position the planetary gear _P L, and _{P R,} the planetary gear _P L, _{P R} and the rotatably supported sun gear _S L, _{S R} and the ring gear _R L, _{R R} and planet carrier _C L provided coaxially, and _{C R} Have Here, the sun gear _S L, _{S R} and planetary gears _P L, the _{P R} is an external gear having gear teeth on the outer periphery, a ring gear _R L, _{R R} is an internal gear having gear teeth on the inner periphery. Planetary gears _P L, _{P R} is engaged the sun gear _S L, _{S R} and the ring gear _R L, in the _{R R.}

Planetary gear mechanism 30L, the 30R, the planetary carrier _C L, the sun gear _S L in case of fixing the _{C R, S R} and the ring gear _R L, and the _{R R} is rotated in the reverse direction. Thus, expressed in the velocity diagram shown in FIG. 6, the ring gear _R L, _{R R} and the sun gear _S L, _{S R} are disposed on the opposite side of the planet carrier _C L, _{C R.}

  As shown in FIGS. 4 and 5, the torque TM1 generated by the electric motor 2L is transmitted from the input gear shaft 12L to the intermediate gear shaft 13L. The torque transmitted to the intermediate gear shaft 13L is amplified by the gear device 30 so that the left and right torque difference is amplified, and the output side small gear 13b, the output gear 14a, and the output gear of the intermediate gear shaft 13L are sequentially transmitted via the planetary gear mechanism 30L. It is transmitted to the shaft 14L. A driving torque TL (FIG. 6) is output from the output gear shaft 14L to the driving wheel 61L.

  Torque TM2 generated by the electric motor 2R is transmitted from the input gear shaft 12R to the intermediate gear shaft 13R. The torque transmitted to the intermediate gear shaft 13R is amplified by the gear device 30 so that the difference in torque between the left and right sides is sequentially increased through the planetary gear mechanism 30R, and the output side small gear 13b, the output gear 14a, and the output gear of the intermediate gear shaft 13R. It is transmitted to the shaft 14R. A driving torque TR (FIG. 6) is output from the output gear shaft 14R to the driving wheel 61R.

<About driving torque>
Here, the driving torque transmitted by the gear device 30 will be described with reference to a velocity diagram shown in FIG. Since the gear unit 30 is configured by combining two identical single pinion planetary gear mechanisms 30L and 30R, it can be represented by two velocity diagrams as shown in FIG. Here, for easy understanding, the two speed diagrams are shifted up and down, the speed diagram of one planetary gear mechanism 30L is shown on the upper side of FIG. 6, and the speed line of the other planetary gear mechanism 30R is shown on the lower side of FIG. The figure is shown.

Originally, as shown in FIG. 5, the torques TM1 and TM2 output from the electric motors 2L and 2R are connected to the ring gears via the input side external gears 13a meshing with the input gears 12a of the input gear shafts 12L and 12R. Since it is input to R _L and R _R , a reduction ratio is applied. Further, since the drive torques TL and TR output from the gear device 30 are transmitted to the left and right drive wheels 61L and 61R via the output side small gear 13b meshing with the output gear 14a, a reduction ratio is applied.
These left and right wheel drive devices are applied with these reduction ratios, but for the sake of easy understanding, hereinafter, as shown in FIG. The torque input to R _L and R _R remains TM1 and TM2, and the drive torque remains TL and TR.

Two single-pinion planetary gear mechanism 30L, 30R is due to the use of gear elements of the same number of teeth, in the velocity diagram, the distance between the ring gear R _L and planet carrier C _L and the ring gear R _R and the planetary carrier the distance between the C _R is equal to the distance "a". Moreover, equally the distance between the sun gear S _L and the distance between the planet carrier C _L and the sun gear S _R and the planetary carrier C _R, is the distance between "b".

Planet carrier _C L, the ring gear from the _{C R R} L, _R length to _R and planet carrier _C L, the sun gear from the _{C R S} L, the ratio of length to _{S R} is the ring gear _R L, the number of teeth of the _{R R} Zr equal the reciprocal of (1 / Zr) and the sun gear _S L, and the ratio of the reciprocal of the number of teeth Zs of _{S R} (1 / Zs). Therefore, a = (1 / Zr) and b = (1 / Zs).

The following formula (1) is calculated from the balance of moment M with reference to the point of R _R. In FIG. 6, the arrow direction M in the figure is the positive direction of the moment.
a * TR + (a + b) * TL- (b + 2a) * TM1 = 0 (1)
The following equation (2) is calculated from the balance of moment M with reference to point _RL .
-A.TL- (a + b) .TR + (b + 2a) .TM2 = 0 (2)

The following formula (3) is obtained from the formula (1) + the formula (2).
-B. (TR-TL) + (2a + b). (TM2-TM1) = 0
(TR-TL) = ((2a + b) / b). (TM2-TM1) (3)
(2a + b) / b in Expression (3) is the torque difference amplification factor α. When a = 1 / Zr and b = 1 / Zs are substituted, α = (Zr + 2Zs) / Zr, and the following torque difference amplification factor α is obtained.
α = (Zr + 2Zs) / Zr

In this example, the input from the electric motor 2L, 2R (FIG. 5) _is, R L, _{R R,} and the drive wheels 61L, the output of the 61R (FIG. 5) becomes _{S R + C L, S L} + C R.
As shown in FIGS. 5 and 6, when the difference in rotational speed between the first coupling member 31 and the second coupling member 32 is small, the two electric motors 2L and 2R generate different torques TM1 and TM2 and input them. When the torque difference ΔTIN (= (TM1−TM2)) is given, the input torque difference ΔTIN is amplified in the gear device 30, and a driving torque difference α · ΔTIN larger than the input torque difference ΔTIN can be obtained.

That is, even if the input torque difference ΔTIN is small, the input torque difference ΔTIN can be amplified by the torque difference amplification factor α (= (Zr + 2Zs) / Zr) in the gear device 30. Therefore, a driving torque difference ΔTOUT (= α · (TM2−TM1)) larger than the input torque difference ΔTIN can be given to the driving torques TL and TR transmitted to the left driving wheel 61L and the right driving wheel 61R.
In addition, when the rotational speeds of the left and right drive wheels 61L and 61R are equal, relative rotation does not occur in the two coupling elements in the gear device 30, but when the rotational speeds of the left and right drive wheels 61L and 61R are different, the gear device. The two coupling elements in 30 absorb the rotational speed difference between the left and right drive wheels 61L and 61R by causing relative rotation in accordance with the rotational speed difference between the left and right drive wheels 61L and 61R.

<About abnormality detection devices>
As shown in FIG. 1, the abnormality detection device 68 detects an abnormality of the gear of the gear device 30. The abnormality of the gear is, for example, a gear tooth defect, a crack, or the like. The driving wheels 61L and 61R and the driven wheels 62L and 62R of the vehicle are provided with rotation speed sensors 70 to 73 for detecting the rotation speed of each wheel, and a signal corresponding to the rotation speed of each wheel is output to the abnormality detection device 68. To do. The output signal of the steering angle sensor 69 is input to the abnormality detection device 68 via the host ECU 66 and the like.

FIG. 7 is a block diagram of a control system such as the abnormality detection device 68.
The abnormality detection device 68 includes a rotational speed difference calculation unit 74, a correction unit 75, a determination unit 76, and an abnormality report unit 77. The rotational speed difference calculating means 74 acquires the rotational speeds (wheel speeds) of the left and right drive wheels 61L and 61R (FIG. 1) from the rotational speed sensors 70 and 71 for the left and right drive wheels 61L and 61R (FIG. 1). The rotational speed difference between the left and right drive wheels 61L, 61R (FIG. 1) is calculated.

The correcting means 75 corrects the rotational speed difference with a reference rotational speed difference. In this example, the reference rotational speed difference is the rotational speed difference between the left and right driven wheels 62L and 62R (FIG. 1). The correcting means 75 calculates, for example, the difference between the rotational speed difference between the driving wheels 61L and 61R (FIG. 1) and the rotational speed difference between the driven wheels 62L and 62R (FIG. 1), thereby driving the driving wheels 61L and 61R (FIG. The rotational speed difference of 1) can be corrected.
Based on the rotational speed difference corrected by the correction means 75, the determination means 76 determines whether an abnormality has occurred in the gear. Specifically, the determination unit 76 determines that an abnormality has occurred in the gear of the gear device 30 (FIG. 1) when the rotational speed difference corrected by the correction unit 75 periodically exceeds a threshold value. Even if it is correct | amended, the determination means 76 determines that there is no abnormality in the said gear, when it is not periodic. Note that whether or not the rotational speed difference is periodically equal to or greater than the threshold may be determined using various known methods. For example, it may be determined that the rotational speed difference is periodically greater than or equal to the threshold when the rotational speed difference is greater than or equal to a predetermined number of times within a predetermined time. In addition, when there is an abnormality in a specific part of the gear, when the specific part meshes, the rotational speed difference becomes greater than or equal to a threshold value. Based on the above, it may be determined whether the rotational speed difference is periodically equal to or greater than a threshold value.

  The abnormality reporting unit 77 receives information indicating that an abnormality has occurred in the gear from the determining unit 76 and outputs abnormality occurrence information to the control device 67 and the host ECU 66. When the abnormality occurrence information is input, the host ECU 66 causes the display device 78 installed on, for example, a console panel of the vehicle to display the abnormality of the gear. In this case, the vehicle can be moved to a evacuation site, a repair shop, or the like by self-propelling by accurately detecting an abnormality in the gear of the gear device 30 (FIG. 1) from the beginning of the occurrence of the abnormality.

  The control device 67 includes output limiting means 79 that limits the output of the electric motors 2L and 2R (FIG. 1) when the abnormality occurrence information is input. For example, the output limiting unit 79 limits the motor torque command value given to the inverter device 64 by several percent to several tens percent. As a result, it is possible to prevent the vehicle from being obstructed. However, it is not limited to the said restrictions. For example, the degree of limitation of the motor torque command value may be increased according to the magnitude of the rotational speed difference.

  FIG. 8 is a flowchart of abnormality detection executed by this abnormality detection device. As shown in FIGS. 7 and 8, after the start of this process, the abnormality detection device 68 acquires the rotation speed of each wheel from each of the rotation speed sensors 70 to 73 (step S1). Next, the rotational speed difference calculating means 74 calculates the rotational speed difference between the left and right drive wheels (step S2: rotational speed difference calculating step), and the correcting means 75 calculates the reference rotational speed difference (step S3). The correcting means 75 corrects the rotational speed difference between the left and right drive wheels with the reference rotational speed difference (step S4).

  The determination unit 76 determines whether or not the corrected rotational speed difference is greater than or equal to a threshold value (step S5: determination step). If the corrected rotational speed difference is less than the threshold value (step S5: NO), this process ends. When the corrected rotational speed difference is equal to or greater than the threshold value (step S5: YES), the determination unit 76 determines whether or not the rotational speed difference that is equal to or greater than the threshold value has periodicity (step S6). If the rotational speed difference does not have periodicity (step S6: NO), this processing is terminated. If the rotational speed difference has periodicity (step S6: YES), it is determined that the gear is abnormal (step S6: NO). Step S7). Thereafter, this process is terminated.

  FIG. 9 is a diagram illustrating an example of the rotation speed of the wheel when there is an abnormality in the gear of the gear device. The graph of FIG. 9A is the rotation speed of the left wheel, and the graph of FIG. 9B is the rotation speed of the right wheel. 9 (a) and 9 (b), the solid line is the drive wheel, and the broken line is the driven wheel. In the example of FIG. 9, the vehicle is slowly accelerating, and the rotational speed of the wheels slowly increases with time.

  If there is an abnormality in which the gears of this vehicle gear unit are missing, even if the two electric motors output the same magnitude of torque, the left and right drive wheels have a periodicity corresponding to the abnormal part of the gears. Torque difference occurs. For this reason, the torque of one drive wheel increases periodically, and the torque of the other drive wheel decreases periodically. As a result, the rotational speed of the driving wheel periodically changes in the opposite direction on the left and right. FIG. 9 shows a change in rotational speed when the torque of the left drive wheel periodically increases and the torque of the right drive wheel decreases periodically.

  The solid line in FIG. 9C indicates the magnitude of the rotational speed difference between the left and right drive wheels, and the broken line in FIG. 9C indicates the magnitude of the rotational speed difference between the left and right driven wheels. In this example, the rotational speed difference between the left and right driven wheels is the reference rotational speed difference. As described above, since the left and right drive wheels change in rotation speed in opposite directions, the rotation speed change can be further emphasized by calculating the difference in rotation speed between the left and right drive wheels. Since the change in the rotational speed can be emphasized in this way, the abnormality can be detected with high accuracy even in the initial stage of occurrence of the gear abnormality.

  Further, the correction means 75 (FIG. 7) corrects the rotational speed difference between the left and right drive wheels using a reference rotational speed difference that is substantially free from periodic rotational speed changes. FIG. 9D shows the corrected rotational speed difference of the driving wheels. The difference in rotational speed between the left and right drive wheels is corrected by calculating the difference between the rotational speed difference between the left and right drive wheels and the difference in rotational speed between the left and right driven wheels. The determination means 76 (FIG. 7) determines that an abnormality has occurred in the gear when the corrected value periodically becomes greater than or equal to the threshold value.

  In this example, abnormality detection is performed based on whether or not the rotational speed difference periodically exceeds a threshold value. However, a periodic change in the rotational speed difference is detected by frequency analysis of the rotational speed difference signal. Abnormality determination may be performed. The determination means 76 (FIG. 7) can be considered that the rotational speed difference is periodically greater than or equal to the threshold when a specific frequency due to gear abnormality is periodically detected. The specific frequency is determined by, for example, one or both of testing and simulation.

  FIG. 10 is a diagram showing another example of the rotational speed of the wheel when there is an abnormality in the gear. The graph of FIG. 10A is the rotation speed of the left wheel, and the graph of FIG. 10B is the rotation speed of the right wheel. In FIGS. 10A, 10B, and 10C, the solid line is the driving wheel, and the broken line is the driven wheel. The example of FIG. 10 shows the rotational speed of each wheel when the vehicle is accelerating while turning right.

  When the vehicle turns right, the rotational speed of the right wheel that is inside the turn decreases, and the rotational speed of the left wheel that is outside the turn increases. Therefore, when the magnitude of the difference in rotational speed between the left and right drive wheels and the magnitude of the difference in rotational speed between the right and left driven wheels are calculated, as shown in FIG. The speed difference increases. However, as in FIG. 9, the difference in rotational speed between the left and right driven wheels and the difference in rotational speed between the left and right driven wheels are calculated by using the rotational speed difference between the left and right driven wheels as the reference rotational speed difference. As shown in FIG. 10 (d), the difference in rotational speed between the left and right drive wheels can be corrected to suppress the influence of turning.

  According to the abnormality detection device 68 of the left and right wheel drive device 1 described above, the determination means 76 determines whether or not the calculated rotational speed difference is periodically greater than or equal to a threshold value. The determination unit 76 determines that an abnormality has occurred in the gear device 30 when the rotational speed difference periodically exceeds the threshold value. When an abnormality has occurred in the gear device 30, even if the two electric motors 2L and 2R output equal magnitude torque, the left and right drive wheels 61L and 61R have a period according to the abnormal part of the gear. Torque difference occurs. For this reason, the torque of one drive wheel 61L (61R) increases periodically, and the torque of the other drive wheel 61R (61L) decreases periodically. Therefore, the rotational speed of the drive wheels periodically changes in opposite directions between the left and right drive wheels 61L and 61R. Therefore, by calculating the difference in rotational speed between the left and right drive wheels 61L and 61R, it is possible to further emphasize the change in rotational speed of the drive wheels 61L and 61R. Therefore, the abnormality can be detected with high accuracy even in the initial stage of occurrence of the abnormality of the gear of the gear device 30.

<About other embodiments>
In the following description, when only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  The correcting means 75 calculates the rotational speed difference between the left and right drive wheels 61L and 61R and the rotational speed difference between the left and right driven wheels 62L and 62R, respectively, and further calculates the rotational speed difference between the left and right drive wheels 61L and 61R. The difference in rotational speed difference between the driven wheels 62L and 62R is calculated, but the invention is not limited to such correction. For example, the correction means 75 calculates the rotational speed difference between the left driving wheel 61L and the left driven wheel 62L, calculates the rotational speed difference between the right driving wheel 61R and the right driven wheel 62R, and then rotates these rotational speeds. You may perform correction | amendment which calculates | requires the difference of a difference.

  As shown in FIG. 7, the correction means 75 replaces the reference rotational speed difference based on the rotational speed difference between the driven wheels 62L and 62R with the left and right driving wheels calculated from the vehicle model Md using at least the vehicle speed and the steering wheel angle. The rotation speed difference may be a reference rotation speed difference used for correction. A planar two-degree-of-freedom model or the like can be applied as the vehicle model Md. The vehicle is provided with a vehicle speed sensor 80 that detects the vehicle speed that is the speed of the vehicle.

  The correction means 75 acquires the vehicle speed from the vehicle speed sensor 80, acquires the steering wheel angle from the steering angle sensor 69, and calculates the rotational speed difference between the left and right drive wheels, which is the reference rotational speed difference, from the vehicle model Md. By calculating the reference rotational speed difference using the vehicle model Md, it is possible to reduce the influence due to the difference in the wheel position between the driving wheel and the driven wheel. Therefore, the abnormality of the gear device can be detected with higher accuracy.

  Instead of the vehicle speed sensor 80, for example, the average speed of the left and right driven wheels may be used as the vehicle speed of the actual vehicle. The correction means 75 calculates the rotational speed difference at the driving wheel position from the rotational speeds of the left and right driven wheels using the yaw rate of the actual vehicle, and the rotational speed difference at the driving wheel position is used as the reference rotational speed difference. good.

In the embodiment shown in FIGS. 2 and 3, to form the planet carrier C _L of the left side of the planetary gear mechanism 30L, a first coupling member 31 is coupled and the sun gear S _R of the right planetary gear mechanisms 30R, left and the sun gear S _L of the planetary gear mechanism 30L for, although the planet carrier C _R of the right planetary gear mechanism 30R form a second coupling member 32 is coupled, but is not limited to this example.

For example, the sun gear S _L of the left side of the planetary gear mechanism 30L, a first coupling member 31 is formed is bonded and the ring gear R _R of the right planetary gear mechanisms 30R, a ring gear R _L on the left side of the planetary gear mechanism 30L it may have a structure in which the sun gear S _R of the right planetary gear mechanism 30R form a second coupling member 32 are coupled.
Other, a planet carrier C _L of the left side of the planetary gear mechanism 30L, may have a structure in which the ring gear R _R of the right planetary gear mechanism 30R form a second coupling member 32 are coupled.
The drive source of the left and right wheel drive device is not limited to an electric motor, and an internal combustion engine such as a gasoline engine may be used.

  Needle roller bearings are used as the bearings 45 and 46 between the first and second coupling members 31 and 32. For example, rolling bearings such as deep groove ball bearings and angular ball bearings can also be applied. It is.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Left-right wheel drive device 2L, 2R ... 1st, 2nd electric motor (drive source)
3L, 3R ... Deceleration device 30 ... Gear devices 30L, 30R ... Planetary gear mechanisms 61L, 61R ... Drive wheels 62L, 62R ... Driven wheels 67 ... Control device 68 ... Abnormality detection device 74 ... Rotational speed difference calculation means 75 ... Correction means 76 ... Determination means 79 ... Output restriction means

Claims (9)

Two drive sources mounted on the vehicle and independently controllable, and provided between the two drive sources and the left and right drive wheels, amplifying the difference in torque applied from the two drive sources, In the abnormality detection device of the left and right wheel drive device comprising a speed reducer that transmits to each of the drive wheels,
The speed reducer includes a gear device having two planetary gear mechanisms,
The abnormality detection device is:
A rotational speed difference calculating means for calculating a rotational speed difference between the left and right drive wheels;
An abnormality detection device for a left and right wheel drive device, comprising: a determination unit that determines whether an abnormality has occurred in the gear device based on the rotation speed difference calculated by the rotation speed difference calculation unit.   The abnormality detection device for a left and right wheel drive device according to claim 1, further comprising a correction unit that corrects the rotational speed difference using a reference rotational speed difference as a reference, and the determination unit is corrected by the correction unit. An abnormality detection device for a left and right wheel drive device that determines whether an abnormality has occurred in the gear device using a difference in rotational speed.   The abnormality detection device for a left and right wheel drive device according to claim 2, wherein the reference rotational speed difference in the correction means is a value based on a rotational speed difference between left and right driven wheels in the vehicle. .   4. The abnormality detection device for a left and right wheel drive device according to claim 3, wherein the correction means calculates a difference in rotation speed at the drive wheel position from left and right rotation speeds of the driven wheel, and the rotation speed at the drive wheel position. An abnormality detection device for a left and right wheel drive device having a difference as the reference rotational speed difference.   The abnormality detection device for a left and right wheel drive device according to claim 2, wherein the reference rotational speed difference in the correction means is based on a rotational speed difference between the left and right drive wheels calculated from the vehicle model using at least the vehicle speed and the steering wheel angle. An abnormality detection device for the left and right wheel drive device.   The abnormality detection device for a left and right wheel drive device according to any one of claims 1 to 5, wherein the determination means determines that the rotational speed difference calculated by the previous rotational speed difference calculation means is periodically greater than or equal to a threshold value. An abnormality detection device for a left and right wheel drive device that determines that an abnormality has occurred in the gear device in the previous period.   The abnormality detection device for a left and right wheel drive device according to any one of claims 1 to 6, further comprising a control device for controlling the drive source, wherein after the abnormality is detected by the determination means, the output of the drive source is output. An abnormality detection device for a left and right wheel drive device comprising an output limiting means for limiting the control device. An abnormality detection method using the abnormality detection device for a left and right wheel drive device according to any one of claims 1 to 7,
A rotational speed difference calculating step for calculating a rotational speed difference between the left and right drive wheels;
And a determination step for determining whether or not an abnormality has occurred in the gear device based on the rotation speed difference calculated in the rotation speed difference calculation step.   A vehicle comprising the abnormality detection device for a left and right wheel drive device according to any one of claims 1 to 7.

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