JP2017078449A - Left and right wheel drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce size and weight of a left and right wheel drive unit including a torque difference amplification mechanism by reducing the size of the torque difference amplification mechanism.SOLUTION: A left and right wheel drive unit comprises: two electric motors 2, 3; left and right drive wheels 4L, 4R; and a gear unit 5 which is arranged between the electric motors 2, 3 and the drive wheels 4L, 4R, and in which two planetary gear mechanisms are coaxially combined. The planetary gear mechanisms 10A, 10B have ring gears for input, planetary carriers for output which are coaxially arranged with the ring gears, and sun gears coaxially arranged with the ring gears, respectively. The gear unit 5 has a first coupling member 11 for coupling planetary carriers C1 to the sun gears S2, and a second coupling member 12 for coupling the sun gears S1 to the planetary carriers C2. The electric motor 2 is connected to the ring gear R1, the electric motor 3 is connected to the ring gear R2, the drive wheel 4L is connected to the first coupling member 11, and the drive wheel 4R is connected to the second coupling member 12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a left and right wheel drive device capable of amplifying a torque difference and transmitting drive torque from two independent drive sources to left and right drive wheels.

  In vehicles such as electric cars, electric motors are arranged on the left and right drive wheels, respectively, and each electric motor is controlled independently to give an appropriate drive torque difference between the left and right wheels, thereby controlling the turning moment of the vehicle It is known to do. For example, when each electric motor is independently connected to the left and right drive wheels via a reduction gear, the rotational speed of each electric motor is reduced by the respective reduction gear, and the output torque of each electric motor is Amplified by each reduction gear and transmitted to the left and right drive wheels. Here, in order to make the behavior of the vehicle right and left turn the same, each electric motor has the same output characteristics, and each reduction gear has the same reduction ratio. Therefore, in order to give a drive torque difference between the left and right drive wheels, a torque difference is given between the electric motors. However, since the respective reduction ratios are the same, the drive torque and the left and right drive of the left and right drive wheels The ratio of the drive torque difference between the wheels is the same as the ratio of the output torque difference between the electric motors and the output torque difference between the electric motors. In other words, a drive torque difference larger than the reduction ratio times the output torque difference between the electric motors cannot be given between the left and right drive wheels.

  By the way, it is effective to generate a large drive torque difference between the left and right drive wheels in order to achieve smooth turning of the vehicle and to suppress changes in vehicle behavior such as extreme understeer and extreme oversteer. There is a case. For this reason, it is desirable to amplify the difference between the torques output from the two electric motors and transmit them to the left and right drive wheels.

  Therefore, Patent Documents 1 and 2 include a gear device in which two planetary gear mechanisms having three elements and two degrees of freedom are coaxially arranged between two drive sources and left and right drive wheels, and the difference in torque is measured. An amplified left and right wheel drive is disclosed.

  A left and right wheel drive device (hereinafter referred to as Conventional Technology 1) disclosed in Patent Document 1 will be described with reference to FIGS. FIG. 5 is a skeleton diagram showing the left and right drive wheel device according to Prior Art 1, and FIG. 6 is a velocity diagram for explaining the torque difference amplification factor by the left and right wheel drive device according to Prior Art 1.

  The left and right wheel drive device 100 includes a first electric motor 102 and a second electric motor 103 mounted on a vehicle, a left drive wheel 104L and a right drive wheel 104R, a gear device 105 and a reduction gear train 106 provided therebetween. , 107, 108, 109.

  The first electric motor 102 and the second electric motor 103 are operated by electric power from a battery (not shown) mounted on the vehicle, are individually controlled by an electronic control device (not shown), and generate different torques for output. can do. The output shaft 102a of the first electric motor 102 and the output shaft 103a of the second electric motor 103 are connected to the coupling members 111 and 112 of the gear device 105 through reduction gear trains 106 and 107, respectively. The output from the gear unit 105 is given to the left and right drive wheels 104L and 104R via the reduction gear trains 108 and 109.

  The gear device 105 is configured by combining two identical planetary gear mechanisms 110A and 110B having three elements and two degrees of freedom on the same axis. For example, a single pinion planetary gear mechanism is employed as the planetary gear mechanisms 110A and 110B. The single pinion planetary gear mechanism includes a sun gear S and a ring gear R provided on the same axis, a plurality of planetary gears P positioned between the sun gear S and the ring gear R, and a planetary gear P that rotatably supports the sun gear S and The ring gear R and the planetary carrier C provided on the same axis are used. Here, the sun gear S and the planetary gear P are external gears having gear teeth on the outer periphery, and the ring gear R is an internal gear having gear teeth on the inner periphery. The planetary gear P meshes with the sun gear S and the ring gear R. In the planetary gear mechanism, when the carrier C is fixed, the sun gear S and the ring gear R rotate in opposite directions. Therefore, the ring gear R and the sun gear S are arranged on the opposite side with respect to the carrier C in the velocity diagram. In other words, the ring gear R is disposed on the opposite side of the sun gear S across the carrier C.

  In the velocity diagram shown in FIG. 6, the ratio of the length from the carrier C to the ring gear R and the length from the carrier C to the sun gear S is the reciprocal (1 / Zr) of the number of teeth Zr of the ring gear R and the teeth of the sun gear S. It is equal to the ratio of the reciprocal number (1 / Zs) of the number Zs.

  As shown in FIG. 5, the gear device 105 includes a first planetary gear mechanism 110A having a sun gear S1, a carrier C1, a planetary gear P1, and a ring gear R1, and a second gear gear having a sun gear S2, a carrier C2, a planetary gear P2, and a ring gear R2. The planetary gear mechanism 110B is coaxially combined.

  The sun gear S1 of the first planetary gear mechanism 110A and the ring gear R2 of the second planetary gear mechanism 110B are coupled to form a first coupling member 111, and the ring gear R1 of the first planetary gear mechanism 110A and the second planetary gear mechanism are coupled. 110B sun gear S2 is coupled to form second coupling member 112. Torque TM1 generated by the first electric motor 102 is input to the first coupling member 111 via the reduction gear train 106, and torque TM2 generated by the second electric motor 103 is input to the second coupling member 112. It is input via the reduction gear train 107. Further, the carrier C1 of the first planetary gear mechanism 110A and the carrier C2 of the second planetary gear mechanism 110B are connected to the left and right drive wheels 104L and 104R via the reduction gear trains 108 and 109, respectively, and an output is taken out.

  Here, the driving torque transmitted by the gear device 105 will be described with reference to a velocity diagram shown in FIG. Since the gear unit 105 is configured by combining two identical single pinion planetary gear mechanisms 110A and 110B, it can be represented by two velocity diagrams as shown in FIG. Here, for easy understanding, the two velocity diagrams are shifted up and down, the velocity diagram of the first planetary gear mechanism 110A is shown on the upper side, and the velocity diagram of the second planetary gear mechanism 110B is shown on the lower side.

  Further, in the speed diagram of the first planetary gear mechanism 110A and the speed diagram of the second planetary gear mechanism 110B, the sun gear S and the ring gear R are arranged in the left-right direction. That is, in FIG. 6, the ring gear R2 of the second planetary gear mechanism 110B is disposed under the sun gear S1 of the first planetary gear mechanism 110A, and the second planetary gear mechanism 110B is disposed under the ring gear R1 of the first planetary gear mechanism 110A. A sun gear S2 is arranged.

  In the gear device 105, the elements located at both ends of the two velocity diagrams shown in FIG. 6 are joined to each other as shown by the broken lines in the figure to form a first coupling member 111 and a second coupling member 112. The The torques TM1 and TM2 output from the first electric motor 102 and the second electric motor 103 are input to the first connecting member 111 and the second connecting member 112, respectively. Originally, the torques TM1 and TM2 output from the electric motors 102 and 103 are input to the coupling members 111 and 112 via the reduction gear trains 106 and 107, and thus a reduction ratio is applied. For the sake of simplicity, the reduction ratio is omitted in the speed diagram and the explanation of each calculation formula, and the torques input to the coupling members 111 and 112 remain TM1 and TM2.

  On the other hand, drive torques TL and TR transmitted to the left and right drive wheels 104L and 104R from the carriers C1 and C2 positioned in the middle on the velocity diagram are output.

  By giving the torque difference (input torque difference) ΔTIN (= TM2−TM1) to the drive torques TM1 and TM2 generated by the first electric motor 102 and the second electric motor 103 by the gear device 105 configured in this way. A drive torque difference ΔTOUT (= TL−TR) can be generated between the drive torque TL transmitted to the left drive wheel 104L and the drive torque TR transmitted to the right drive wheel 104R. That is, according to the gear device 105, the relationship of the following expression (1) is obtained. The coefficient α is a torque difference amplification factor.

  (TL-TR) = α × (TM2-TM1) (1)

  The torque difference amplification factor α of the gear device 105 according to prior art 1 will be described. Here, since the two single pinion planetary gear mechanisms 110A and 110B use gear elements having the same number of teeth, the distance between the ring gear R1 and the carrier C1 and the distance between the ring gear R2 and the carrier C2 in the velocity diagram. The distances are equal and this is a. Further, the distance between the sun gear S1 and the carrier C1 and the distance between the sun gear S2 and the carrier C2 are also equal, which is b.

  Torques TM1 and TM2 of the first electric motor 102 and the second electric motor 103 are input to the first coupling member 111 and the second coupling member 112 at the left and right ends, respectively, and the drive torques TL and TR are taken out from the carriers C1 and C2.

From the relationship between torque input and output, the following equation (2) is obtained.
TR + TL = TM1 + TM2 (2)

Also, the equation of moment with reference to the left end (R1, S2 portion) in the figure is the following equation (3). In FIG. 6, the arrow M direction indicates the + moment direction.
0 = aTL + bTR− (a + b) TM1 (3)

  Summarizing TL and TR from these equations (2) and (3), the following equations (4) and (5) are obtained.

TL = ((a / (ba)) + 1) .TM2- (a / (ba)). TM1 (4)
TR = ((a / (ba)) + 1) .TM1- (a / (ba)). TM2 (5)

  From these equations (4) and (5), the drive torque difference (TL-TR) is the following equation (6).

(TL-TR) = ((a + b) / (ba)). (TM2-TM1) (6)

  In the case of a single pinion planetary gear mechanism, the length a is the reciprocal (1 / Zr) of the number of teeth Zr of the ring gear R, and the length b is the reciprocal (1 / Zs) of the number of teeth Zs of the sun gear S. Is rewritten as equation (7).

  (TL-TR) = ((Zr + Zs) / (Zr-Zs)). (TM2-TM1) (7)

  From the above equation (7), the torque difference amplification factor α is (Zr + Zs) / (Zr−Zs).

  As described above, in the prior art 1, the inputs from the first and second electric motors 102 and 103 are S1 + R2 and S2 + R1, and the outputs to the drive wheels 104L and 104R are C1 and C2.

  When different torques TM1 and TM2 are generated by the two electric motors 102 and 103 to give an input torque difference ΔTIN (= (TM2−TM1)), the gear device 105 amplifies the input torque difference ΔTIN, and the input torque difference ΔTIN Large driving torque difference α · ΔTIN can be obtained. That is, even if the input torque difference ΔTIN is small, the gear device 105 can amplify the input torque difference ΔTIN with a predetermined torque difference amplification factor α, and the drive torque transmitted to the left drive wheel 104L and the right drive wheel 104R. A driving torque difference ΔTOUT (= α · (TM2−TM1)) larger than the input torque difference ΔTIN can be given to TL and TR.

  The left and right wheel drive device disclosed in Patent Document 2 (hereinafter referred to as Conventional Technology 2) will be described with reference to FIGS. FIG. 7 is a skeleton diagram showing the left and right drive wheel device according to the prior art 2, and FIG. 8 is a velocity diagram for explaining the torque difference amplification factor by the left and right wheel drive device according to the prior art 2. In FIG. 7, in order to make the difference from the prior art 1 easier to understand, the electric motors 102 and 103 are arranged on the left and right sides so as to be the same as the conventional example 1, and the same components are denoted by the same reference numerals. ing.

  As shown in FIG. 7, the left and right wheel drive device 100 includes a first electric motor 102 and a second electric motor 103 mounted on a vehicle, a left drive wheel 104L and a right drive wheel 104R, and gears provided therebetween. A device 105 and reduction gear trains 106 and 107 are provided.

  The first electric motor 102 and the second electric motor 103 are operated by electric power from a battery (not shown) mounted on the vehicle, are individually controlled by an electronic control device (not shown), and generate different torques for output. can do. The output shaft 102a of the first electric motor 102 and the output shaft 103a of the second electric motor 103 are connected to the sun gears S1 and S2 of the gear device 105 through reduction gear trains 106 and 107, respectively. The output from the gear unit 105 is given to the left and right drive wheels 104L, 104R.

  Like the prior art 1, the gear device 105 of the prior art 2 is configured by combining two identical planetary gear mechanisms 110A and 110B having three elements and two degrees of freedom on the same axis. For example, a single pinion planetary gear mechanism is employed as the planetary gear mechanisms 110A and 110B.

  Then, the planet carrier C1 of the first planetary gear mechanism 110A and the ring gear R2 of the second planetary gear mechanism 110B are coupled to form the first coupling member 111, and the ring gear R1 and the second planetary gear of the first planetary gear mechanism 110A. The second carrier 112 is formed by coupling with the planet carrier C2 of the mechanism 110B. Torque TM1 generated by the first electric motor 102 is input to the sun gear S1 of the first planetary gear mechanism 110A via the reduction gear train 106, and torque TM2 generated by the second electric motor 103 is supplied via the reduction gear train 107. To the sun gear S2 of the second planetary gear mechanism 110B.

  The first coupling member 111 and the second coupling member 112 are connected to the left and right drive wheels 104L and 104R, respectively, and output is taken out.

  As described above, in the conventional technique 2, the inputs from the electric motors 102 and 103 are S1 and S2, and the outputs to the drive wheels 104L and 104R are C1 + R2 and C2 + R1.

  Here, the driving torque transmitted by the gear device 105 of the prior art 2 will be described with reference to a velocity diagram shown in FIG. Since the gear unit 105 is configured by combining two identical single pinion planetary gear mechanisms 110A and 110B, it can be represented by two velocity diagrams as shown in FIG. Here, for easy understanding, the two velocity diagrams are shifted up and down, the velocity diagram of the first planetary gear mechanism 110A is shown on the upper side, and the velocity diagram of the second planetary gear mechanism 110B is shown on the lower side. Similarly to the description in the prior art 1, in the following speed diagrams and calculation formulas, the reduction ratios in the reduction gear trains 106 and 107 are omitted, and the torques input to the sun gears S1 and S2 are omitted. To TM1 and TM2.

  In the gear device 105, the planetary carrier C1 and the ring gear R2 and the planetary carrier C2 and the ring gear R1 shown in FIG. 8 are respectively connected as shown by the broken line in the figure to form a first connecting member 111 and a second connecting member 112. The The torques TM1 and TM2 output from the first electric motor 102 and the second electric motor 103 are input to the sun gears S1 and S2, respectively. On the other hand, the drive torques TL and TR transmitted to the left and right drive wheels 104L and 104R from the first coupling member 111 and the second coupling member 112 positioned in the middle on the velocity diagram are output.

  Also with the gear device 105 configured in this manner, a torque difference (input torque difference) ΔTIN (= TM2−TM1) is given to the drive torques TM1 and TM2 generated by the first electric motor 102 and the second electric motor 103. Thus, a drive torque difference ΔTOUT (= TL−TR) can be generated between the drive torque TL transmitted to the left drive wheel 104L and the drive torque TR transmitted to the right drive wheel 104R.

  The torque difference amplification factor α of the gear device 105 according to prior art 2 will be described. Also in this prior art 2, since the two single pinion planetary gear mechanisms 110A, 110B use gear elements having the same number of teeth, the distance between the ring gear R1 and the carrier C1 and the ring gear R2 in the speed diagram The distance to the carrier C2 is equal, and this is a. Further, the distance between the sun gear S1 and the carrier C1 and the distance between the sun gear S2 and the carrier C2 are also equal, which is b.

  In this prior art 2, the speed diagram of FIG. 8 is obtained, and the torque difference amplification factor α can be obtained in consideration of the balance of torque in the speed diagram. In FIG. 8, the arrow M direction indicates the + moment direction.

The following equation (8) is calculated from the balance of moment M with reference to the point of S2.
b.TR + (a + b) .TL- (a + 2b) .TM1 = 0 (8)
The following equation (9) is calculated from the balance of moment M with respect to the point of S1.
-B.TL- (a + b) .TR + (a + 2b) .TM2 = 0 (9)

The following expression (10) is calculated from the expression (8) + the expression (9).
a. (TR-TL)-(a + 2b). (TM2-TM1) = 0
(TR-TL) = ((a + 2b) / a). (TM2-TM1) (10)

(A + 2b) / a in the equation (10) is the torque difference amplification factor α.
When a = 1 / Zr and b = 1 / Zs are substituted, α = (2Zr + Zs) / Zs.

  As described above, in the prior art 2, the inputs from the electric motors 102 and 103 are S1 and S2, and the outputs to the drive wheels 104L and 104R are C1 + R2 and C2 + R1, respectively, and the torque difference amplification factor α is (2Zr + Zs). / Zs.

  As described above, in the prior arts 1 and 2, when the two electric motors 102 and 103 generate different torques TM1 and TM2 to give the input torque difference ΔTIN, the gear device 105 receives the input torque difference ΔTIN. Is amplified, and a driving torque difference ΔTOUT larger than the input torque difference ΔTIN can be obtained.

JP 2015-21594 A Japanese Patent No. 4907390

  In the prior arts 1 and 2 described above, since the ring member R is included in the connecting member that connects the two planetary gear mechanisms that are the torque difference amplifying mechanisms, one of the connecting members that connect either the left or right link gear R to another member. One of them must have a larger diameter than the other ring gear R, so that there has been a problem that the apparatus becomes larger.

  When the electric motor and these gear devices are mounted on the vehicle body, it is desirable to reduce the size. Accordingly, an object of the present invention is to reduce the torque difference amplifying mechanism to reduce the size and weight of the left and right drive wheel device including the torque difference amplifying mechanism.

In order to solve the above problems, the present invention provides two drive sources mounted on a vehicle and independently controllable, left and right drive wheels, and between the two drive sources and the left and right drive wheels. A left and right wheel drive device provided with two coaxial elements of three-element two-degree-of-freedom planetary gear mechanisms on the same axis, wherein each of the planetary gear mechanisms includes an input ring gear and the ring gear. And an output planetary carrier provided coaxially with the ring gear and a sun gear provided coaxially with the ring gear, and the gear shaft device is configured to couple one planetary carrier with the other sun gear. One coupling member, and a second coupling member that couples one sun gear and the other planet carrier, wherein one of the drive sources is connected to one ring gear, and the other drive source is coupled to the other Connected to the ring gear,
One of the driving wheels is connected to the first coupling member, and the other driving wheel is connected to the second coupling member.

  In the gear device, the first coupling member and the second coupling member are arranged coaxially, and one coupling member has a hollow shaft and the other coupling member has a shaft inserted through the hollow shaft. And a shaft passing between the two planetary gear shafts can be configured in a double structure.

  The inserted shaft is a rotating shaft having one end connected to the other sun gear and the other end is provided through the center of the one sun gear so as to connect the two planetary gear mechanisms. Can be configured.

  Further, both of the two drive sources may be constituted by electric motors.

  A reduction gear mechanism may be provided between the output shaft of the drive source and the input ring gear of the planetary gear mechanism, and a reduction gear mechanism may be provided between the gear device and the drive wheel.

  As described above, according to the present invention, the connection between the two planetary gear mechanisms of the gear device that is the torque difference amplifying mechanism is a connection between the sun gear and the planet carrier, and a connection member larger in diameter than the ring gear is not required. The torque difference amplification mechanism can be reduced, and the left and right wheel drive device including the torque difference amplification mechanism can be reduced in size and weight.

It is a skeleton figure which shows the left-right drive wheel apparatus which concerns on embodiment of this invention. It is a skeleton figure which shows the left-right drive wheel apparatus which concerns on other embodiment of this invention. It is a speed diagram for demonstrating the torque difference amplification factor by the left-right wheel drive device based on this invention. It is explanatory drawing of the electric vehicle carrying the left-right drive wheel apparatus of this invention. It is a skeleton figure which shows the left-right drive wheel apparatus which concerns on the prior art 1. FIG. It is a speed diagram for demonstrating the torque difference amplification factor by the left-right wheel drive device which concerns on the prior art 1. FIG. It is a skeleton figure which shows the left-right drive wheel apparatus which concerns on the prior art 2. FIG. It is a speed diagram for demonstrating the torque difference amplification factor by the left-right wheel drive device which concerns on the prior art 2. FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
The electric vehicle AM shown in FIG. 4 is a rear wheel drive system, and includes a chassis 50, drive wheels 4L and 4R as rear wheels, front wheels 14L and 14R, a left and right wheel drive device 1 and a battery 6 according to the present invention. And an inverter 7 and the like.

  The left and right wheel drive device 1 includes a first electric motor 2 and a second electric motor 3 mounted on a vehicle, a left drive wheel 4L and a right drive wheel 4R, a gear device 5 and a reduction gear train 15 provided therebetween. , 16. The output from the left and right wheel drive device 1 is transmitted to the left and right drive wheels 4L and 4R via the constant velocity joint 8. In this embodiment, the first electric motor 2 and the second electric motor 3 use the same standard electric motor having the same maximum output.

  In addition, as a mounting form of the left and right wheel drive device 1, a front wheel drive system and a four wheel drive system may be used in addition to the rear wheel drive system shown in FIG.

  As shown in FIGS. 1 and 4, the first electric motor 2 and the second electric motor 3 are operated by electric power supplied from a battery 6 mounted on the vehicle via an inverter 7. The first electric motor 2 and the second electric motor 3 are individually controlled by an electronic control device (not shown), and can generate and output different torques. The output shaft 2a of the first electric motor 2 and the output shaft 3a of the second electric motor 3 are connected to the ring gears R1 and R2 of the gear device 5 through reduction gear trains 15 and 16, respectively. The output from the gear unit 5 is given to the left and right drive wheels 4L, 4R. The reduction gear trains 15 and 16 are configured with the same gear ratio.

  The gear device 5 is configured by combining two identical planetary gear mechanisms 10A, 10B having three elements and two degrees of freedom on the same axis. For example, a single pinion planetary gear mechanism is employed for the planetary gear mechanisms 10A and 10B. The single pinion planetary gear mechanism includes a sun gear S and a ring gear R provided on the same axis, a plurality of planetary gears P positioned between the sun gear S and the ring gear R, and a planetary gear P that rotatably supports the sun gear S and The ring gear R and the planetary carrier C provided on the same axis are used. Here, the sun gear S and the planetary gear P are external gears having gear teeth on the outer periphery, and the ring gear R is an internal gear having gear teeth on the inner periphery. The planetary gear P meshes with the sun gear S and the ring gear R.

  As described above, in the planetary gear mechanism, when the carrier C is fixed, the sun gear S and the ring gear R rotate in opposite directions. Therefore, the ring gear R and the sun gear S are opposite to the carrier C in the velocity diagram. Placed in.

  As shown in FIG. 1, the gear device 5 includes a first planetary gear mechanism 10A having a sun gear S1, a carrier C1, a planetary gear P1 and a ring gear R1, and a second gear having a sun gear S2, a carrier C2, a planetary gear P2 and a ring gear R2. The planetary gear mechanism 10B is configured to be coaxially combined.

  Then, the planet carrier C1 of the first planetary gear mechanism 10A and the sun gear S2 of the second planetary gear mechanism 10B are coupled to form the first coupling member 11, and the sun gear S1 and the second planetary gear of the first planetary gear mechanism 10A are combined. The second carrier 12 is formed by coupling with the planet carrier C2 of the mechanism 10B.

  Torque TM1 generated by the first electric motor 2 is input to the ring gear R1 of the first planetary gear mechanism 10A via the reduction gear train 15, and the torque generated by the second electric motor 3 to the ring gear R2 of the second planetary gear mechanism 10B. TM2 is input via the reduction gear train 15.

  The first coupling member 11 is connected to the left drive wheel 4L, and the drive torque TL is taken out. The second coupling member 12 is connected to the right drive wheel 4R and the drive torque TR is taken out.

  FIG. 2 is a skeleton diagram showing another embodiment of the present invention. In this other embodiment, the outputs from the first and second electric motors 2 and 3 are transmitted to the ring gears R1 and R2 of the first and second planetary gear mechanisms 10A and 10B without passing through the reduction gear train. The output from the first coupling member 11 and the second coupling member 12 passes through the inside of the output shafts 2a and 3a of the hollow shafts of the first and second electric motors 2 and 3 via the reduction gear trains 17 and 18. It is given to the drive wheels 4L and 4R after decelerating. The reduction gear trains 17 and 18 are configured with the same gear ratio. Other configurations are the same as those of the embodiment shown in FIG.

  In the example of FIGS. 1 and 2 described above, the second coupling member 12 includes a hollow shaft extending along the axial center of the gear device 5, and the first coupling member is included therein. 11 is inserted. The first coupling member 11 includes a shaft extending along the axis of the gear device 5, and the first coupling member 11 and the second coupling member 12 are arranged on the same axis, and these shafts are arranged. Has a double structure.

  The first coupling member 11 is configured by, for example, a solid shaft. The first coupling member 11 that is a solid shaft has one end (right end in the drawing) serving as the rotation shaft of the sun gear S2, and the other end (left end in the drawing). ) Is provided through the sun gear S1 and connected to the planet carrier C1. The second coupling member 12 that is a hollow shaft has one end (left end in the figure) serving as the rotation shaft of the sun gear S1, and the other end (right end in the figure) connected to the planet carrier C2. In this way, the two planetary gear mechanisms 10A and 10B are connected.

  2, the connection from the first coupling member 11 to the reduction gear train 17 and the connection from the planet carrier C2 to the reduction gear train 18 are provided through the motor shafts of the electric motors 2 and 3, respectively. It has been. That is, the motor shafts of the electric motors 2 and 3 are configured to include hollow shafts, and the shafts connected to the respective reduction gear trains 17 and 18 are arranged coaxially, and these shafts have a double structure. Yes.

  In the example of FIG. 1, the output from the gear unit 5 is transmitted to the drive wheels 4L and 4R without passing through the reduction gear train, but the output from the gear unit 5 is transmitted through the reduction gear train. You may comprise. In the example of FIG. 2, the output from the electric motors 2 and 3 is transmitted to the gear device 5 without passing through the reduction gear train, but the output from the electric motors 2 and 3 is transmitted through the reduction gear train. You may comprise as follows.

  Here, the driving torque transmitted by the gear device 5 will be described with reference to a velocity diagram shown in FIG. Since the gear device 5 is configured by combining two identical single pinion planetary gear mechanisms 10A and 10B, 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 the first planetary gear mechanism 10A is shown on the upper side, and the speed diagram of the second planetary gear mechanism 10B is shown on the lower side. Originally, in FIG. 1, the torques TM1 and TM2 output from the electric motors 2 and 3 are input to the ring gears R1 and R2 through the reduction gear trains 15 and 16, respectively. In FIG. 2, the drive torques TL and TR extracted from the gear unit 5 are transmitted to the left and right drive wheels 4L and 4R via the reduction gear trains 17 and 18, respectively. Therefore, similarly to the description in the prior arts 1 and 2, the reduction ratio is omitted in the description of the speed diagrams and the calculation formulas, and the torque input to the ring gears R1 and R2 remains TM1 and TM2, and the drive torque Is the same as TL and TR.

  Since the two single pinion planetary gear mechanisms 10A and 10B use gear elements having the same number of teeth, the distance between the ring gear R1 and the carrier C1 and the distance between the ring gear R2 and the carrier C2 are equal in the velocity diagram. This is a. Further, the distance between the sun gear S1 and the carrier C1 and the distance between the sun gear S2 and the carrier C2 are also equal, which is b. The ratio of the length from the carrier C to the ring gear R and the length from the carrier C to the sun gear S is the reciprocal of the number of teeth Zr of the ring gear R (1 / Zr) and the reciprocal of the number of teeth Zs of the sun gear S (1 / Zs). Is equal to the ratio of Therefore, a = (1 / Zr) and b = (1 / Zs).

The following equation (11) is calculated from the balance of the moment M with respect to the point R2. In FIG. 3, the arrow direction M in the figure is the positive direction of the moment.
a * TR + (a + b) * TL- (b + 2a) * TM1 = 0 (11)
The following equation (12) is calculated from the balance of the moment M based on the point R1.
-A.TL- (a + b) .TR + (b + 2a) .TM2 = 0 (12)

The following expression (13) is obtained from the expression (11) + the expression (12).
-B. (TR-TL) + (2a + b). (TM2-TM1) = 0
(TR-TL) = ((2a + b) / b). (TM2-TM1) (13)

  (2a + b) / b in the equation (13) is the torque 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 the present invention, inputs from the first and second electric motors 2 and 3 are R1 and R2, and outputs to the drive wheels 4L and 4R are S2 + C1 and S1 + C2.

  When different torques TM1 and TM2 are generated by the two electric motors 2 and 3 to give an input torque difference ΔTIN (= (TM2−TM1)), the input torque difference ΔTIN is amplified in the gear device 5 and the input torque difference A driving torque difference α · ΔTIN larger than ΔTIN can be obtained. That is, even if the input torque difference ΔTIN is small, the input torque difference ΔTIN can be amplified with the above-described torque difference amplification factor α (= (Zr + 2Zs) / Zr) in the gear device 5, and the left drive wheel 4L and the right drive wheel 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 4R.

  As described above, in the prior arts 1 and 2, since the ring gear R is included in the left and right connecting members of the two planetary gear mechanisms of the gear device 105 that is a torque difference amplification mechanism, either the left or right ring gear is connected to another member. One of the coupling members must always have a larger diameter than the other ring gear R.

  On the other hand, in the present invention, the connection between the two planetary gear mechanisms 10A and 10B of the gear device 5 which is a torque difference amplification mechanism is the connection between the sun gear S and the planet carrier C, and a connecting member having a larger diameter than the ring gear R is required. do not do. For this reason, in the present invention, the torque difference amplification mechanism can be made smaller than those of the prior arts 1 and 2. And the electric vehicle drive device including the torque difference amplification mechanism can be made small and light. As a result, there are advantages in that the degree of freedom of the vehicle body mounting layout of the drive device itself and peripheral accessories is improved, and that the cabin space is expanded by downsizing the drive device.

  Next, a description will be given of how many decelerations that affect the physique of the left and right wheel drive device. In the present invention and the prior art 2, the output shaft of the gear device constituting the torque difference amplification mechanism can be coaxial with the drive wheel. Since the gear device that constitutes the torque difference amplifying mechanism does not decelerate or increase the output, in order to decelerate the power of the electric motor, a reduction gear train is placed before, after, or before and after the gear device that constitutes the torque difference amplifying mechanism. is necessary.

  If the motor power of the electric motor is decelerated and output, and if the motor shaft of the electric motor is not made into a special structure, such as a hollow structure, the invention and the prior art 2 can be achieved with at least one-stage reduction (two axes). To do.

  On the other hand, in the prior art 1, the planetary carrier C serves as an output to the drive wheel, and because the power of the electric motor is input to the sun gear S and the ring gear R, a special structure such as hollowing the motor shaft of the electric motor. If not, as shown in FIG. 5, a two-stage reduction (three axes) is required to put a reduction gear train before and after the gear unit constituting the torque difference amplification mechanism. For this reason, since the drive device is enlarged, the degree of freedom of the mounting layout is reduced, and the number of gears is increased, so that the cost of components tends to increase. This is advantageous in terms of weight reduction and mounting layout.

  In addition, a structure in which the motor shaft of the electric motor is hollow and the number of steps is reduced by passing the shaft inside is also conceivable. However, in this invention and the prior art 2, if the number of axes is reduced, the motor shaft of the electric motor and the output shaft of the gear device are coaxial. In contrast, in the prior art 1, in order to make the motor shaft of the electric motor and the output shaft of the gear device coaxial with each other, two axes must be reduced, and the output shaft from the planet carrier is used as one of the electric motors. It is not reasonable with considerable difficulty such as having a larger diameter hollow shaft.

  If the number of teeth is the same, α in the present invention and prior arts 1 and 2 are different from the relational expression of the torque difference amplification factor α. However, if the number of teeth is changed, it is possible in part to set the same α between different mechanisms. For example, if the number of teeth is sun gear: Zs = 40, planetary gear: Zp = 20, ring gear: Zr = 80, in the present invention, α = 2, and Zs = 27, Zp = 27, Zr = 81 Same as 1. However, for example, in the prior art 2 in which Zs = 27, Zp = 27, and Zr = 81, α = 7, but in order to set α = 7 in the present invention, Zs is calculated from the relational expression of the torque difference amplification factor α. It is necessary to be three times Zr, and it is not realized. On the other hand, in order to set α = 2 in the prior art 2, it is necessary that Zs is twice as large as Zr, which is not the same. The amount of torque difference amplification factor α is set as appropriate depending on the travel performance to be imparted to the vehicle.

  In the above-described embodiment, the case where the electric motors 2 and 3 are used as the two drive sources and the electric motors of the same standard having the same maximum output is illustrated, but the two drive sources are not limited thereto.

  The vehicle on which the left and right wheel drive device 1 is mounted is not limited to an electric vehicle or a hybrid electric vehicle, and may be, for example, a fuel cell vehicle using the first electric motor 2 and the second electric motor 3 as drive sources.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. The scope of the present invention is claimed. And the equivalent meanings recited in the claims, and all modifications within the scope are included.

1: Left and right wheel drive device 2: First electric motor 3: Second electric motor 4L: Left drive wheel 4R: Right drive wheel 14L: Front wheel 14R: Front wheel 5: Gear device 6: Battery 7: Inverter 8: Constant velocity joint 10A : First planetary gear mechanism 10B: second planetary gear mechanism 11: first coupling member 12: second coupling member 15: reduction gear train 16: reduction gear train 17: reduction gear train 18: reduction gear train 50: chassis AM: Electric vehicle C1: Planetary carrier C2: Planetary carrier P1: Planetary gear P2: Planetary gear R1: Ring gear R2: Ring gear S1: Sun gear S2: Sun gear TL, TR: Driving torque TM1, TM2: Torque α: Torque difference gain

Claims (6)

A planetary gear mechanism that is provided between the two drive sources mounted on the vehicle and can be controlled independently, the left and right drive wheels, and the two drive sources and the left and right drive wheels. A left and right wheel drive device comprising two gear units combined on the same axis,
Each of the planetary gear mechanisms includes an input ring gear, an output planetary carrier provided coaxially with the ring gear, and a sun gear provided coaxially with the ring gear,
The gear shaft device includes a first coupling member that couples one planet carrier and the other sun gear, and a second coupling member that couples one sun gear and the other planet carrier,
One of the drive sources is connected to one ring gear, the other drive source is connected to the other ring gear,
One of the driving wheels is connected to the first coupling member, and the other driving wheel is connected to the second coupling member.   In the gear device, the first coupling member and the second coupling member are arranged coaxially, one coupling member has a hollow shaft, and the other coupling member has a shaft inserted through the hollow shaft. The left and right wheel drive device according to claim 1, wherein the shaft passing between the two planetary gear shafts has a double structure.   The inserted shaft is a rotating shaft having one end connected to the other sun gear, the other end is provided through the center of the one sun gear, and connects the two planetary gear mechanisms. The left and right wheel drive device according to claim 2.   The left and right wheel drive device according to any one of claims 1 to 3, wherein each of the two drive sources is an electric motor.   5. The left and right wheel drive device according to claim 1, wherein a reduction gear mechanism is provided between an output shaft of the drive source and an input ring gear of the planetary gear mechanism. .   The left and right wheel drive device according to any one of claims 1 to 4, wherein a reduction gear mechanism is provided between the gear device and the drive wheel.

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