JP2006226484A - Power-split type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mount a transverse installation engine on a front wheel driving car, by promoting miniaturization of a toroidal type continuously variable transmission, while improving transmission efficiency and transmission torque capacity. <P>SOLUTION: This power-split type continuously variable transmission is constituted by combining a variator 20 with a motive power distributing mechanism using a planetary gear mechanism 4. This single cavity system toroidal type variator 20 is arranged in parallel to an input shaft 3 of a torque converter 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power split type continuously variable transmission used as a transmission for an automobile, for example.

  As a power split type continuously variable transmission used for an automobile, in particular, an automobile transmission of a front-wheel drive vehicle (so-called FF vehicle) of a horizontally mounted engine, for example, one described in Patent Document 1 is known. This power split type continuously variable transmission is a double-cavity toroid that is provided coaxially with an input shaft connected to the engine and coaxially with the input shaft, and a power roller is tilted between the input disk and the output disk. Type variator (hereinafter referred to as a variator), a planetary gear mechanism that is configured in parallel with the variator and has a set of planetary gears having two degrees of freedom, and power that transmits the power of the variator to the planetary gear mechanism The transmission mechanism includes a second shaft that directly transmits power to the planetary gear mechanism, bypassing the variator from the input shaft, and an output shaft.

  In this continuously variable transmission, the planetary gear mechanism is interlocked with a direct mode (forward low speed mode) in which power is directly transmitted to the output shaft by interlocking the planetary gear mechanism, and the planetary gear mechanism having two degrees of freedom is interlocked in this direct mode. By canceling and transmitting the power between the planetary gear mechanism having two degrees of freedom and the input shaft through the second shaft, the power circulated from the planetary gear mechanism to the variator is added to the input power. It flows into the planetary gear mechanism via the second shaft, and the output shaft is provided with a torque split mode (forward high-speed mode) in which the difference between the inflowing power and the power circulating power is output as output power. Such a continuously variable transmission having a torque split mode in which power circulates is called a power split (or torque split) type continuously variable transmission.

  In the prior art, a double cavity toroidal variator is used in order to cope with the output torque of the engine. For this reason, the axial dimension of the whole apparatus becomes large, and it becomes difficult to use a starting device such as a torque converter generally used for a continuously variable transmission, and a mode switching clutch is used as a starting clutch. When a clutch is used as the starting device, the control for starting smoothly becomes complicated. Furthermore, it is necessary to add a device for absorbing the torsional vibration of the engine.

  As a means for shortening the axial dimension of the entire continuously variable transmission, for example, one shown in FIG. 8 of Patent Document 2 is known. The power split type continuously variable transmission includes an input shaft connected to a driving source, a single cavity toroidal variator in which a power roller is tiltably contacted between a pair of input disks and an output disk, A power transmission mechanism including two sets of planetary gear mechanisms that transmit the output of the variator to the output shaft, and a sub-rotation shaft that bypasses the input shaft and transmits directly to the planetary gear mechanism.

This continuously variable transmission also has a direct mode and a torque split mode.
JP 2002-39319 A Japanese Patent No. 2929592

  However, in the power split type continuously variable transmission shown in the examples of Patent Document 1 and Patent Document 2, the power passing through the variator is smaller than the input power in the forward high speed mode, but in the forward low speed mode, The power passing through the variator is equal to the input power, and as a result, there is a drawback that it does not contribute to the miniaturization of the variator and the improvement of the transmission efficiency in the forward low speed mode.

  Further, in the example of Patent Document 2, since a single cavity type toroidal variator is used, a large axial force acting between an input disk and an output disk is supported by a bearing as shown in FIG. Further, there is a disadvantage that the friction loss generated in the bearing is large and the transmission efficiency is deteriorated.

  Furthermore, in the example of Patent Document 2, since the single cavity type toroidal variator is used, the torque transmission capability of the variator is halved compared to the double cavity type toroidal variator, and can be applied only to a low torque engine.

  An object of the present invention is to provide a power split type continuously variable transmission having a small size, light weight, low cost, and high transmission efficiency.

  The power split type continuously variable transmission of the present invention includes an input shaft connected to a drive source, an output shaft that outputs power based on the input shaft, a first rotating element, a second rotating element, and a third rotating element. A differential gear mechanism that distributes the power input from the input shaft to the first rotating element to the second rotating element and the third rotating element, and the second rotating element of the differential gear mechanism. Power is transmitted from the first power transmission mechanism to be coupled, the second power transmission mechanism to be coupled to the third rotating element of the differential gear mechanism, and the first power transmission mechanism or the second power transmission mechanism, One first disk, one second disk opposite to the first disk, a power roller that is tiltably rolled between the first disk and the second disk, and the first disk One disc is inserted through the power roller A continuously variable transmission mechanism having a loading mechanism that presses against two discs, a third power that is coupled to the second power transmission mechanism and the output shaft, and transmits power from the second power transmission mechanism to the output shaft; A transmission mechanism, a fourth power transmission mechanism coupled to the first power transmission mechanism and the output shaft, for transmitting power from the first power transmission mechanism to the output shaft, and from the third power transmission mechanism. The forward low speed mode for transmitting power to the output shaft, the forward high speed mode for transmitting power from the fourth power transmission mechanism to the output shaft, and the third power rotating in the direction opposite to the rotational direction of the input shaft. A power transmission switching mechanism that switches between a reverse mode for transmitting power from the transmission mechanism to the output shaft, and a shift control device that controls the power transmission switching mechanism, and the first and second of the continuously variable transmission mechanism. This Characterized by disposing the center of rotation in parallel with the input shaft.

  According to the present invention, the torque input to the continuously variable transmission mechanism can always be limited to 1/3 to 1/2 of the input torque of the continuously variable transmission. Therefore, a continuously variable transmission mechanism having a small torque capacity, specifically, a single cavity type continuously variable transmission mechanism can be used. In other words, even if it is necessary to use the normal double cavity type for the input torque of the continuously variable transmission, the configuration of the present invention can use the single cavity type. The axial dimension can be shortened. By shortening the axial dimension, a combination with a starting device such as a torque converter becomes possible.

  Further, when the torque capacity of the continuously variable transmission is the same, there is an effect that the overall cost can be reduced and the size can be reduced by reducing the torque capacity of the continuously variable transmission mechanism and the number of parts.

  Furthermore, since the power transmitted by the continuously variable transmission mechanism can be reduced in all modes, transmission efficiency can be improved in all modes.

  FIG. 1 is a configuration diagram of a power split type continuously variable transmission according to the present invention. The power split type continuously variable transmission includes a drive transmission shaft 1 connected to an engine E as a drive source, a starting device 2 such as a torque converter, an input shaft (turbine shaft) 3 connected to the starting device 2, A planetary gear mechanism (differential gear mechanism) 4 that divides the transmitted power, a single-cavity toroidal continuously variable transmission mechanism (hereinafter referred to as a variator) 20 that is arranged in parallel with the planetary gear mechanism 4, and the planetary gear mechanism 4. First and second power transmission mechanisms 10 and 11 for transmitting power between the first power transmission mechanism 10 and the variator 20, and third and fourth power transmission mechanisms 18 and 22 connected to the first and second power transmission mechanisms 10 and 11, respectively. And drive wheels W to which power is transmitted from the third and fourth power transmission mechanisms 18 and 22.

  The power of the engine E input from the drive transmission shaft 1 is transmitted to the input shaft 3 and the ring gear (first rotating element) 4e of the planetary gear mechanism 4 through the starting device 2. A part of the power transmitted to the ring gear 4e is transmitted to the sun gear 4a (second rotating element) of the planetary gear mechanism 4, and the remaining power is transmitted to the carrier 4d (third rotating element). That is, the planetary gear mechanism 4 acts as a power distribution mechanism.

  The power transmitted to the sun gear 4a is transmitted to the variator 20 disposed in parallel with the bypass shaft 13 through the bypass shaft 13 and the first power transmission mechanism 10 disposed coaxially with the input shaft 3. . Here, the first power transmission mechanism 10 includes a first gear 10a and a second gear 10b meshing with the first gear 10a. The first gear 10a is fixed to the bypass shaft 13, while the second gear 10b. Is fixed to the variator input shaft 5.

  The variator 20 includes a variator input shaft 5, a mechanical loading mechanism 6 that is connected to the variator input shaft 5, presses the first disk 7 against the second disk 9 via the power roller 8, and transmits power. A first disk 7 that can rotate relative to the variator input shaft 5 within a predetermined range and a second disk 9 that can rotate relative to the variator input shaft 5 are coaxially arranged. The first and second disks 7 and 9 are installed facing each other, and a plurality of power rollers 8 that are tiltably in contact with each other are disposed between the first disk 7 and the second disk 9. In this way, the power of the first disk 7 is transmitted to the second disk 9 via the power roller 8.

  The second disk 9 is coupled to the third gear 11a of the second power transmission mechanism 11, and the power of the second disk 9 is the third gear 11a and the fifth gear 11c meshing with the third gear 11a. It is transmitted via a second power transmission mechanism 11 comprising a fourth gear 11b meshing with the fifth gear 11c.

  Here, the engine E side end of the variator input shaft 5 is rotatably supported by the case 28 via a bearing 26. Further, the end portion of the second disk 9 is also rotatably supported by the case 28 via a bearing 27. The loading mechanism 6 is disposed on the opposite side of the bearings 26 and 27 with the variator 20 interposed therebetween. The bearings 26 and 27 are disposed so as to overlap when viewed in the direction perpendicular to the starting device 2 or the input shaft 3 or the planetary gear mechanism 4 and the input shaft 3. Since the bearings 26 and 27 of the continuously variable transmission mechanism 20 are disposed in the axial direction so as to face the input shaft 3 on the engine side, the axial dimension can be shortened.

  On the other hand, the carrier 4 d of the planetary gear mechanism 4 is coupled to the fourth gear 11 b of the second power transmission mechanism 11. As a result, the power via the sun gear 4a, the counter shaft 13, the first power transmission mechanism 10 and the variator 20 of the planetary gear mechanism 4 and the power via the carrier 4d of the planetary gear mechanism 4 are the second power transmission mechanism 11. Join at. The power merged by the second power transmission mechanism 11 is transmitted to the third power transmission mechanism 18.

  The third power transmission mechanism 18 includes a sixth gear 18a, a seventh gear 18b that meshes with the sixth gear 18a, and an eighth gear 18c that meshes with the seventh gear 18b. The seventh gear 18 b is coupled to the output shaft 19 provided in parallel with the bypass shaft 13. The sixth gear 18 a is rotatably disposed coaxially with the bypass shaft 13 and is selectively connected to the fourth gear 11 b of the second power transmission mechanism 11 via the forward low-speed clutch 15. The eighth gear 18 c is fixed to the reverse counter shaft 14, and the reverse counter shaft 14 is selectively connected to the fifth gear 11 c of the second power transmission mechanism 11 via the reverse clutch 17. Therefore, when the forward low speed clutch 15 is engaged, power is transmitted from the carrier 4 d to the output shaft 19 via the fourth gear 11 b and the third power transmission mechanism 18. When the reverse clutch 17 is engaged, power is transmitted from the fifth gear 11c to the output shaft 19 via the reverse counter shaft 14, the eighth gear 18c, the sixth gear 18a, and the seventh gear 18b.

  The fourth power transmission mechanism 22 includes a ninth gear 22a and a tenth gear 22b that meshes with the ninth gear 22a. The ninth gear 22a is selectively connected to the bypass shaft 13 (or the first gear 10a) via the forward high speed clutch 16. The tenth gear 22 b is connected to the output shaft 19.

  Further, an eleventh gear 23 a of the speed reducer 23 is connected to the output shaft 19. The speed reducer 23 includes an eleventh gear 23a and a twelfth gear 23b meshing with the eleventh gear 23a. The power transmitted to the twelfth gear 23b is transmitted through the differential gear 24 and the final drive shaft 25 to the wheels W. Is transmitted to.

  The power split type continuously variable transmission is provided with a control device 21 for controlling the engagement of the forward low speed clutch 15, the forward high speed clutch 16, and the reverse clutch 17. For example, the control device 21 determines the forward low speed mode, the forward high speed mode, and the reverse speed mode as shown in the fastening table of Table 1 from the input torque, the engine load, the vehicle speed, the turbine shaft speed, and the like. Engagement release of the forward low speed clutch 15, the forward high speed clutch 16, and the reverse clutch 17 is controlled, and the gear ratio of the variator 20 is also controlled. In the table, ◯ represents fastening (engaged) and x represents release (non-engaged). Each mode will be described later.

なお、バリエータ入力軸５、機械式ローディング機構６及びバリエータ２０を無段変速機構と称し、この無段変速機構に動力を伝達する動力伝達機構の減速比について説明する。

The variator input shaft 5, the mechanical loading mechanism 6, and the variator 20 are referred to as a continuously variable transmission mechanism, and the reduction ratio of the power transmission mechanism that transmits power to the continuously variable transmission mechanism will be described.

The reduction ratio R1 of the first power transmission mechanism 10 is
R1 = 1.0 (1)
Set to.

  The reduction ratio R1 of the first power transmission mechanism 10 is given by the following equation.

R1 = Z10a / Z10b
However, Z10a: The number of teeth of the first gear 10a of the first power transmission mechanism 10
Z10b: Number of teeth of the second gear 10b of the first power transmission mechanism 10 Furthermore, the relationship between the gear ratio α of the planetary gear mechanism 4 and the reduction ratio R2 of the second power transmission mechanism 11 is
α / (1-α) ≈1 / R2 (2)
Set to.

  Here, the gear ratio α of the planetary gear mechanism 4 is given by the following equation.

α = Z4a / Z4e
Z4a: number of teeth of the sun gear 4a of the planetary gear mechanism 4
Z4e: Number of teeth of the ring gear 4e of the planetary gear mechanism 4 The reduction ratio R2 of the second power transmission mechanism 11 is given by the following equation.

R2 = Z11a / Z11b
However, Z11a: Number of teeth of the third gear 11a of the second power transmission mechanism 11
Z11b: Number of teeth of the fourth gear 11b of the second power transmission mechanism 11 Further, the speed ratio V of the variator 20 (V = number of rotations of the first disk 7 / number of rotations of the second disk 9) is set to the maximum acceleration position, that is, the maximum The relationship between the transmission gear ratio Vhigh when set to High and the reduction gear ratio R3f between the seventh gear 18b and the sixth gear 18a of the third power transmission mechanism 18 is as follows.
Vhigh≈R3f (3)
Is set.

  A reduction ratio R3f between the sixth gear 18a and the seventh gear 18b of the third power transmission mechanism 18 is given by the following equation.

R3f = Z18a / Z18b
However, Z18a: Number of teeth of the sixth gear 18a of the third power transmission mechanism 18
Z18b: Number of teeth of the seventh gear 18b of the third power transmission mechanism 18 The operation of the continuously variable transmission mechanism that sets the reduction ratio as described above will be described below.

  The variator input shaft 5 is now stopped, and the variator 20 is at the maximum deceleration position (lowest, where the first disk 7 is the input side and the second disk 9 is the output side), and the forward high speed The clutch 16 and the reverse clutch 17 are in a released state, and the forward low speed clutch 15 is in an engaged state. When the starting device 2 such as a torque converter is operated from this state and the input shaft 3 starts to rotate in a predetermined direction, the ring gear 4e of the planetary gear mechanism 4 is rotated in the same direction as the input shaft 3 as the input shaft 3 rotates. At the same rotation speed. At that time, the power of the ring gear 4e is distributed and transmitted to each of the sun gear 4a and the carrier 4d of the planetary gear mechanism 4. The power distributed to the sun gear 4a passes through the bypass shaft 13, the first power transmission mechanism 10, and the variator 20, that is, the variator input shaft 5, the mechanical loading mechanism 6, the first disk 7, the power roller 8, and the second disk 9. Then, it is transmitted to the second power transmission mechanism 11.

  On the other hand, the power distributed to the carrier 4d is directly transmitted to the second power transmission mechanism 11. The power joined by the second power transmission mechanism 11 is transmitted through the third power transmission mechanism 18 to the output shaft 19 so as to rotate in a predetermined direction and at a lower speed than the drive transmission shaft 1. This is the forward low speed mode. When the variator 20 is shifted to the speed increasing side while maintaining the forward low speed mode, the rotational speed of the output shaft 19 increases and the speed ratio of the power split type continuously variable transmission increases.

  Next, assuming that the forward high speed clutch 16 is engaged and the forward low speed clutch 15 and the reverse clutch 17 are released, the transmission direction of the power passing through the variator 20 is opposite to the forward low speed mode (the second disk 9 is on the input side). The first disk 7 is on the output side). That is, as in the forward low speed mode, the power of the ring gear 4e is distributed and transmitted to each of the sun gear 4a and the carrier 4d of the first planetary gear mechanism 4, but the power distributed to the carrier 4d is the second power transmission mechanism. 11, the variator 20, that is, the second disk 9, the power roller 8, the first disk 7, the mechanical loading mechanism 6, and the variator input shaft 5, and is transmitted to the first power transmission mechanism 10. On the other hand, the power distributed to the sun gear 4 a is transmitted to the first power transmission mechanism 10 via the bypass shaft 13. The power merged by the first power transmission mechanism 10 is transmitted to the output shaft 19 via the forward high speed clutch 16 and the fourth power transmission mechanism 22. This is the forward high speed mode.

  Next, in order to reversely rotate the output shaft 19 in order to reverse the automobile, the forward low speed clutch 15 and the forward high speed clutch 16 are released and the reverse clutch 17 is engaged. As a result, the power distributed by the planetary gear mechanism 4 is merged by the fifth gear 11c of the second power transmission mechanism 11. The power joined by the fifth gear 11c is transmitted to the output shaft 19 through the reverse clutch 17, the reverse counter shaft 14, and the third power transmission mechanism 18. This is the reverse mode.

  Next, the input torque of the input side disk in the forward mode will be described.

First, in the forward low speed mode, the torque T7Low acting on the first disk 7 on the input side of the variator 20 is:
T7Low = αTin (4)
It is represented by

  Tin is a torque acting on the input shaft 3, that is, an input torque to the continuously variable transmission.

In forward high speed mode, torque T9High acting on the second disk 9 on the input side of the variator 20 is
T9High = (1-α) / R2 × Tin (5)
It is represented by

Substituting equation (2) into the above equation, T9High≈αTin (6)
Thus, for example, assuming α = 0.5, T7Low = T9High = 0.5 Tin
It becomes. Therefore, by setting the gear ratios of the planetary gear mechanism 4, the first power transmission mechanism 10 and the second power transmission mechanism 11 as in the formulas (1) and (2), the forward low speed mode and the forward high speed mode are set. It is possible to halve the input torque to the variator 20 compared to the input torque to the continuously variable transmission.

  In the reverse mode, since the same formula as the formula (2) in the forward low speed mode is established, the input torque to the variator 20 can be halved compared to the input torque to the continuously variable transmission. .

Since the gear ratio α of the planetary gear mechanism 4 is normally set in a range of 1/3 to 2/3, if α = 1/3,
T7Low = T9High = Tin / 3
It becomes. In other words, by setting the value of α to 1/3 to 1/2, it is possible to configure a continuously variable transmission that can handle a torque capacity that is two to three times the maximum torque that can be input to the variator 20. .

  Next, the transmission efficiency of the continuously variable transmission will be described. As described above, the input torque of the variator 20 is 1/3 to 1/2 of the input torque to the continuously variable transmission regardless of the mode, and the remaining torque causes the carrier 4d to move in the forward low speed mode and the forward high speed mode. Is routed through the sun gear 4a and the bypass shaft 13. In general, since the transmission efficiency of a toroidal variator is lower than that of a power transmission mechanism composed of gears or the like, the configuration of this embodiment can improve the transmission efficiency.

  Therefore, in the present invention, since the input torque of the continuously variable transmission mechanism can be reduced from the torque input to the continuously variable transmission, the single cavity toroidal variator can be used with a larger input torque of the continuously variable transmission. . Therefore, compared to a continuously variable transmission using a double cavity type toroidal variator, the axial dimension of the continuously variable transmission can be shortened, and a horizontally driven engine front wheel drive vehicle can be used even with a starting device such as a torque converter. It becomes possible to mount on.

  Further, since the variator 20 is arranged in parallel with the input shaft 3, the power directly distributed to the output shaft 19 does not require an additional gear other than the gear meshing with the output shaft 19, and thus is efficiently transmitted to the output shaft 19. Can be done.

  Furthermore, compared to a continuously variable transmission using a double cavity type toroidal variator, the number of parts such as the first and second disks 7 and 9 and the power roller 8 which are costly is halved. It becomes possible.

  In the present embodiment, an example in which the mechanical loading mechanism 6 is used as the loading mechanism has been described. However, any mechanism that can generate a pressing force between the disks may be used. In addition to the mechanical loading mechanism 6, for example, Needless to say, a mechanism using hydraulic pressure may be used.

  Further, in the present embodiment, the sun gear 4a of the planetary gear mechanism 4 is connected to the bypass shaft 13 and the carrier 4d is connected to the second power transmission mechanism 11, but conversely, the sun gear 4a of the planetary gear mechanism 4 is connected to the second power transmission mechanism. Needless to say, the same effect can be obtained by connecting the carrier 4 d to the bypass shaft 13 in the mechanism 11.

  Further, in the present embodiment, a double pinion type planetary gear mechanism is shown as the planetary gear mechanism 4, but it goes without saying that the same effect can be obtained even if it is configured using a single pinion type planetary gear. Since the gear ratio as the continuously variable transmission is different between the case where the double pinion planetary gear mechanism is used and the case where the single pinion planetary gear is used, it may be selected according to a desired gear ratio.

  Furthermore, in the present embodiment, the input torque to the variator 20 in the forward low speed mode and the input torque to the variator 20 in the forward high speed mode are set to substantially the same value. It is also possible to set the input torque to 20 to be larger than the input torque to the variator 20 in the forward low speed mode. In general, in a vehicle such as an automobile, a torque larger than the torque generated by the engine by the starting device 2 such as a torque converter acts on the input shaft 3 in the low speed mode including the starting state. On the other hand, in the high-speed mode, the start-up device 2 such as a normal torque converter operates with a lock-up mechanism, and a large torque is less frequently applied. Therefore, it is possible to set the input torque to the variator 20 in the forward high speed mode to be larger than the input torque to the variator 20 in the forward low speed mode. Since the ratios are different, the desired transmission ratio can be set wider.

  Further, in the present embodiment, the reduction ratio R1 of the first power transmission mechanism 10 is set to a value represented by the formula (1), for example, 1.0, but this value may be an arbitrary value, particularly 1.0. When the value is set to a larger value, the number of rotations of the variator input shaft 5 to the variator 20 can be increased. As a result, the input torque to the variator input shaft 5 can be reduced. In this case, the variator 20 can be further reduced in size, and the speed ratio of the continuously variable transmission is different, so that a desired speed ratio can be set wider.

The block diagram of the power split type continuously variable transmission of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drive transmission shaft 2 ... Starting device 3 ... Input shaft 4 ... Planetary gear mechanism 4a ... Sun gear 4b ... 1st pinion gear 4c ... 2nd pinion gear 4d ... Carrier 4e ... Ring gear 5 ... Variator input shaft 6 ... Mechanical loading mechanism 7 ... 1st disk 8 ... power roller 9 ... 2nd disk 10 ... 1st power transmission mechanism 10a ... 1st gear 10b ... 2nd gear 11 ... 2nd power transmission mechanism 11a ... 3rd gear 11b ... 4th gear 11c ... 5th Gear 13 ... Bypass shaft 14 ... Reverse counter shaft 15 ... Forward low speed clutch 16 ... Forward high speed clutch 17 ... Reverse clutch 18 ... Third power transmission mechanism 18a ... Sixth gear 18b ... Seventh gear 18c ... Eighth gear 19 ... Output shaft DESCRIPTION OF SYMBOLS 20 ... Variator 21 ... Control apparatus 22 ... 4th power transmission mechanism 22a ... 9th gear 22b ... 10th gear 23 ... Reduction gear 23a ... 11th gear 23b ... 1st Gear 24 ... differential gear 25 ... the final drive shaft 26 ... bearing 27 ... bearing 28 ... case E ... engine W ... wheel

Claims (6)

An input shaft connected to the drive source;
An output shaft that outputs power based on this input shaft;
A differential gear comprising a first rotating element, a second rotating element, and a third rotating element, and distributing power input to the first rotating element from the input shaft to the second rotating element and the third rotating element Mechanism,
A first power transmission mechanism coupled to the second rotating element of the differential gear mechanism;
A second power transmission mechanism coupled to the third rotating element of the differential gear mechanism;
The power from the first power transmission mechanism or the second power transmission mechanism is transmitted, one first disk, one second disk opposite to the first disk, the first disk, and the first disk. A continuously variable transmission mechanism having a power roller that is tiltably contacted between two disks and a loading mechanism that presses the first disk against the second disk via the power roller;
A third power transmission mechanism coupled to the second power transmission mechanism and the output shaft, and transmitting power from the second power transmission mechanism to the output shaft;
A fourth power transmission mechanism connected to the first power transmission mechanism and the output shaft, and transmitting power from the first power transmission mechanism to the output shaft;
A forward low speed mode in which power from the third power transmission mechanism is transmitted to the output shaft, a forward high speed mode in which power from the fourth power transmission mechanism is transmitted to the output shaft, and the rotation direction of the input shaft is opposite. A power transmission switching mechanism for switching between a reverse mode for transmitting power from the third power transmission mechanism rotating in the direction to the output shaft;
A shift control device for controlling the power transmission switching mechanism;
A power split type continuously variable transmission, wherein the center of rotation of the first and second disks of the continuously variable transmission mechanism is disposed in parallel with the input shaft. The continuously variable transmission mechanism includes:
A bearing disposed on the drive source side in the axial direction and supporting the first and second discs;
The loading mechanism disposed on the opposite side of the bearing in the axial direction across the continuously variable transmission mechanism;
The power split type continuously variable transmission according to claim 1, wherein the bearing is installed facing the input shaft in a direction perpendicular to the axis.   The power split type continuously variable transmission according to claim 1 or 2, wherein the differential gear mechanism is a single pinion type planetary gear.   3. The power split type continuously variable transmission according to claim 1, wherein the differential gear mechanism is a double pinion type planetary gear. A bypass shaft connected to the first rotating element;
The first power transmission mechanism includes a first gear fixed to the bypass shaft, and a second gear meshing with the first gear and connected to a loading mechanism of the continuously variable transmission mechanism,
The second power transmission mechanism includes a third gear that rotates together with the second disk, a fourth gear that is fixed to the third rotating element, and a fifth gear that meshes with the third and fourth gears,
The third power transmission mechanism includes a sixth gear rotatably provided on the bypass shaft, a seventh gear fixed to the output shaft, and an eighth gear meshing with the seventh gear,
The fourth power transmission mechanism includes a ninth gear rotatably provided on the bypass shaft and a tenth gear fixed to the output shaft,
The power transmission switching mechanism is
A first clutch for engaging the fourth gear and the sixth gear;
A second clutch for engaging the first gear and the ninth gear;
A third clutch for engaging the fifth gear and the eighth gear;
The shift control device engages only the first clutch in the forward low speed mode, engages only the second clutch in the forward high speed mode, and engages only the third clutch in the reverse speed mode. The power split type continuously variable transmission according to claim 1, wherein the power split type continuously variable transmission is controlled.   6. The differential gear mechanism according to claim 1, wherein the first rotating element is a ring gear, the second rotating element is a sun gear, and the third rotating element is a carrier. The power split type continuously variable transmission described in 1.

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