JP2013108588A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve transmission efficiency of a drive force of a continuously variable transmission which can continuously change travel mode among forward movement, stop, and backward movement.SOLUTION: The continuously variable transmission is equipped with: a CVT10 in which drive power from an engine 1 is input, and is output by continuously adjusting the transmission gear ratio; a CVT20 in which the drive power from the engine 1 is inverted and input, and then is output by continuously adjusting the transmission gear ratio; and a planetary gear mechanism 30, in which the outputs from the CVT10 and the CVT20 are input, and the drive power is combined and is output to an output shaft 60a. The output from one of the CVT10 and the CVT20 is input to a sun gear 31 of the planetary gear mechanism 30, the output from the other of the CVT10 and the CVT20 is input to a ring gear 34, and the combined drive power is output from a planetary carrier 33.

Description

  The present invention relates to a continuously variable transmission capable of continuously adjusting a gear ratio.

  Conventionally, a CVT (Continuously Variable Transmission) such as a belt type or a toroidal type is used as an automatic transmission for a vehicle.

  Patent Document 1 discloses a planetary gear amplification type belt-type continuously variable transmission in which a main input from an engine and a sub-input via a CVT are input to a planetary gear and are combined and output to a drive wheel. In this continuously variable transmission, the forward, stop, and reverse travel modes are achieved by combining the main input to which the engine output is directly input and the sub input to which the engine output that is shifted via the CVT is input. It can be changed continuously.

Japanese Patent Laid-Open No. 63-186061

  However, in the continuously variable transmission of Patent Document 1, the driving force by the main input to which the engine output is directly input and the driving force by the sub input to which the engine output shifted through the CVT is input are in opposite directions. There was a risk that the internal loss would increase.

  The present invention has been made in view of the above-described problems, and an object thereof is to improve driving force transmission efficiency in a continuously variable transmission that can continuously change forward, stop, and reverse travel modes. To do.

  The present invention is a continuously variable transmission that shifts the driving force of a prime mover and outputs it to an output shaft, the first transmission mechanism that receives the driving force from the prime mover and adjusts and outputs the gear ratio steplessly. , A second transmission mechanism that receives the driving force from the prime mover and inverts the input and adjusts and outputs the gear ratio steplessly; an output from the first transmission mechanism and an output from the second transmission mechanism; And a planetary gear mechanism that synthesizes the driving force and outputs the resultant to the output shaft. The planetary gear mechanism connects a sun gear that can rotate and a planetary gear that meshes with the outer periphery of the sun gear and can rotate and revolve. A planetary carrier capable of rotating, and a ring gear capable of rotating while meshing with an outer periphery of the planetary gear, and an output from one of the first transmission mechanism and the second transmission mechanism is input to the sun gear. To the ring gear , The output from the other of the first transmission mechanism and the second transmission mechanism is input, combined driving force, characterized in that it is outputted from the planetary carrier.

  In the present invention, the driving force from the prime mover is input to the first transmission mechanism, and is input to the second transmission mechanism by being reversed. Outputs from the first transmission mechanism and the second transmission mechanism are respectively input to the sun gear and the ring gear of the planetary gear mechanism, and the combined driving force is output from the planetary carrier. Therefore, the forward, stop, and reverse travel modes can be continuously changed by adjusting the speed ratio of the first speed change mechanism and the speed change ratio of the second speed change mechanism. At this time, the driving force output from the planetary carrier is the sum of the driving force due to the rotation of the sun gear and the driving force due to the rotation of the ring gear rotating in the direction opposite to the sun gear. Therefore, the transmission efficiency of the driving force can be improved.

1 is a configuration diagram of a continuously variable transmission according to an embodiment of the present invention. It is a figure explaining the relationship of the rotation speed in the continuously variable transmission which concerns on embodiment of this invention. (A) is a figure which shows operation | movement of the planetary gear mechanism at the time of advance of a vehicle, (b) is a figure which shows operation | movement of the planetary gear mechanism at the time of a stop of a vehicle, (c) is reverse movement of a vehicle. It is a figure which shows operation | movement of the planetary gear mechanism in time. It is a figure which illustrates typically the size of the driving force in the planetary gear mechanism.

  Hereinafter, a continuously variable transmission 100 according to an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the continuously variable transmission 100 will be described with reference to FIG.

  The continuously variable transmission 100 is mounted on a vehicle and shifts the driving force input from the engine 1 as a prime mover and outputs it to the drive unit 5. The continuously variable transmission 100 can shift the input driving force to a continuously variable transmission ratio, and can continuously switch forward, stop, and reverse travel modes.

  First, the configuration of the engine 1 that generates the driving force input to the continuously variable transmission 100 and the drive unit 5 that receives the driving force output from the continuously variable transmission 100 will be described.

  The engine 1 is an internal combustion engine that generates a driving force. The output of the engine 1 is output as the rotational force of the output shaft 1a. Instead of the engine 1, a hybrid system that further includes a motor that assists the output of the engine 1 may be used as a prime mover.

  The drive unit 5 includes a differential gear 6 to which the driving force output from the output shaft 60a of the continuously variable transmission 100 is input, and a pair of axles 7 that transmit the driving force from the differential gear 6 to the left and right wheels 8 respectively. Prepare. The driving force output from the continuously variable transmission 100 is decelerated by the differential gear 6, distributed to the left and right axles 7, and transmitted to the wheels 8.

  Next, the internal configuration of the continuously variable transmission 100 will be described in detail.

  The continuously variable transmission 100 includes a CVT 10 as a first transmission mechanism to which driving force is input from the engine 1, a CVT 20 as a second transmission mechanism to which the driving force from the engine 1 is inverted and input, A reversing mechanism 40 that transmits the driving force to CVT 10 and CVT 20 as rotations in opposite directions, and a planetary gear mechanism that outputs the driving force output from CVT 10 and the driving force output from CVT 20 and the combined driving force. 30. The continuously variable transmission 100 includes a speed increasing mechanism 50 that increases the speed of rotation of the output shaft 1a of the engine 1 and transmits it to the reversing mechanism 40, and a speed reduction mechanism that reduces the speed of the output shaft 30a of the planetary gear mechanism 30. 5 and a speed reduction mechanism 60 that transmits to the motor 5.

  The speed increasing mechanism 50 transmits the driving force of the engine 1 input via the clutch 3 while inverting the rotation direction and increasing the speed. The speed increasing mechanism 50 includes a first gear 51 that rotates integrally with the output shaft 1a of the engine 1, and a second gear 52 that meshes with the first gear 51 and rotates in the opposite direction. The first gear 51 is formed with a larger diameter than the second gear 52. As a result, the driving force input to the speed increasing mechanism 50 is reduced and output by an amount corresponding to the increased speed.

  The reversing mechanism 40 outputs the driving force of the engine 1 input through the clutch 3 and the speed increasing mechanism 50 to the CVT 10 and the CVT 20 as rotations in opposite directions. The reversing mechanism 40 includes a reverse rotation gear 41 that rotates integrally with the output shaft 50a of the speed increasing mechanism 50, and a forward rotation gear 42 that meshes with the reverse rotation gear 41 and rotates in the opposite direction.

  The reverse rotation gear 41 is connected to the CVT 20 and transmits the driving force input from the engine 1 via the speed increasing mechanism 50 to the CVT 10 as rotation in the direction opposite to the engine 1 without changing the rotation direction. On the other hand, the forward rotation gear 42 is connected to the CVT 10 and transmits the driving force input from the engine 1 via the speed increasing mechanism 50 to the CVT 20 as a rotation in the same direction as the engine 1 by reversing the rotation direction.

  The reverse rotation gear 41 and the forward rotation gear 42 are formed to have the same outer diameter. As a result, the driving force input to the CVT 10 and the driving force input to the CVT 20 have the same magnitude only when the rotational directions are opposite.

  Between the reversing mechanism 40 and the engine 1, there is provided a clutch 3 capable of connecting / disconnecting transmission of driving force from the engine 1. Thereby, for example, when the vehicle is suddenly decelerated and stopped, the clutch 3 is disengaged, so that the engine 1 can be prevented from stopping even when the timing of switching the continuously variable transmission 100 to the stop mode is delayed.

  The CVT 10 is input by increasing the driving force from the engine 1 and adjusting the gear ratio in a stepless manner for output. The CVT 10 includes a primary pulley 11 to which the driving force of the engine 1 is increased and input, and a secondary pulley 12 to which the driving force is transmitted by a belt 13 that is stretched between the primary pulley 11. The CVT 10 transmits a driving force by a frictional force between the primary pulley 11 and the belt 13 and a frictional force between the secondary pulley 12 and the belt 13.

  The primary pulley 11 and the secondary pulley 12 are piece-like rotating bodies whose outer diameters gradually change along the rotation axis direction.

  The primary pulley 11 rotates in the same direction as the output shaft 1 a of the engine 1 because the driving force from the engine 1 is transmitted through the speed increasing mechanism 50 and the reversing mechanism 40.

  The secondary pulley 12 is rotated by the rotation of the primary pulley 11. The rotation shaft of the secondary pulley 12 is pulled out as the output shaft 10 a and is connected to the transmission mechanism 15.

  When the belt 13 is stretched between a position where the outer diameter of the primary pulley 11 is the smallest and a position where the outer diameter of the secondary pulley 12 is the largest, the transmission ratio of the CVT 10 is minimized. On the other hand, when the belt 13 is passed over a position where the outer diameter of the primary pulley 11 is the maximum and a position where the outer diameter of the secondary pulley 12 is the minimum, the transmission ratio of the CVT 10 is maximized. As described above, in the CVT 10, the gear ratio can be adjusted steplessly according to the positions of the primary pulley 11 and the secondary pulley 12 on which the belt 13 is stretched.

  The transmission mechanism 15 includes a first gear 16 that is coupled to the output shaft 10 a of the CVT 10 and rotates integrally, and a second gear 17 that meshes with the first gear 16. The second gear 17 is connected to a ring gear 34 of a planetary gear mechanism 30 (to be described later) via the output shaft 15a and rotates integrally. The transmission mechanism 15 transmits the driving force input from the output shaft 10a of the CVT 10 via the first gear 16 and the second gear 17 so as to be input from the ring gear 34 of the planetary gear mechanism 30. .

  The CVT 20 is inputted with the driving force from the engine 1 being accelerated and reversed, and adjusting and outputting the gear ratio steplessly. The CVT 20 includes a primary pulley 21 to which the driving force of the engine 1 is input while being accelerated and reversed, and a secondary pulley 22 to which the driving force is transmitted by a belt 23 stretched between the primary pulley 21. The CVT 10 transmits a driving force by a frictional force between the primary pulley 21 and the belt 23 and a frictional force between the secondary pulley 22 and the belt 23.

  Since the driving force from the engine 1 is transmitted only through the speed increasing mechanism 50, the primary pulley 21 rotates in the direction opposite to the output shaft 1a of the engine 1.

  The secondary pulley 22 is rotated by the rotation of the primary pulley 21. The rotation shaft of the secondary pulley 22 is pulled out as the output shaft 20 a and is connected to the transmission mechanism 25.

  Since the configuration of the primary pulley 21 and the secondary pulley 22 is the same as that of the primary pulley 11 and the secondary pulley 12 in the CVT 10, a description of a specific configuration is omitted here.

  The transmission mechanism 25 includes a first gear 26 that is coupled to the output shaft 20 a of the CVT 20 and rotates integrally, and a second gear 27 that meshes with the first gear 26. The second gear 27 is connected to a sun gear 31 of a planetary gear mechanism 30 described later via an output shaft 25a and rotates integrally. The transmission mechanism 25 transmits the driving force input from the output shaft 20a of the CVT 20 via the first gear 26 and the second gear 27 so as to be input from the sun gear 31 of the planetary gear mechanism 30.

  The planetary gear mechanism 30 includes a sun gear 31 that can rotate, a plurality of planetary gears 32 that mesh with the outer periphery of the sun gear 31 and that can rotate and revolve, a planetary carrier 33 that rotatably connects the central axes of the plurality of planetary gears 32, A ring gear 34 that meshes with the outer periphery of the planetary gear 32 and can rotate. The planetary gear mechanism 30 combines the rotation of the sun gear 31 and the rotation of the ring gear 34 to decelerate or increase the input rotation.

  The planetary gear mechanism 30 combines the driving forces input from the CVT 10 and CVT 20 and outputs the combined driving force from the output shaft 30a. The driving force output from the output shaft 30 a of the planetary gear mechanism 30 is output from the output shaft 60 a to the drive unit 5 via the speed reduction mechanism 60.

  The sun gear 31 is a gear having teeth formed on the outer periphery and capable of rotating around a central axis. The output shaft 25a of the transmission mechanism 25 is connected to the central axis of the sun gear 31, and the driving force is transmitted. The driving force output from the CVT 20 is input to the sun gear 31.

  The planetary gear 32 is a gear having teeth formed on the outer periphery and meshing with the outer periphery of the sun gear 31. The planetary gear 32 can rotate about the central axis by meshing with the sun gear 31 and can revolve around the outer periphery of the sun gear 31. A plurality of planetary gears 32 are arranged on the outer periphery of the sun gear 31 at equal angular intervals.

  The planetary carrier 33 is formed in an annular shape and rotates in synchronization with the revolution of the planetary gear 32. On the circumference of the planetary carrier 33, the central axes of all the planetary gears 32 are rotatably supported. The central axis of the planetary carrier 33 is pulled out as the output shaft 30 a and outputs a driving force to the speed reduction mechanism 60.

  The planetary carrier 33 rotates by combining the driving force input from the CVT 10 and the driving force input from the CVT 20. The planetary carrier 33 rotates as the planetary gear 32 revolves around the outer periphery of the sun gear 31.

  The ring gear 34 is a gear having teeth formed on the inner periphery and meshing with the outer periphery of the planetary gear 32. The ring gear 34 can rotate around the central axis by the rotation of the planetary gear 32. The output shaft 15a of the transmission mechanism 15 is connected to the central axis of the ring gear 34, and the driving force is transmitted. The driving force output from the CVT 10 is input to the ring gear 34. The ring gear 34 rotates in the opposite direction to the sun gear 31.

  As described above, in the planetary gear mechanism 30, the output of the CVT 10 is input to the ring gear 34, the output of the CVT 20 is input to the sun gear 31, and the combined driving force is output from the planetary carrier 33. Not limited to this, the output of the CVT 10 may be input to the sun gear 31, the output of the CVT 20 may be input to the ring gear 34, and the combined driving force may be output from the planetary carrier 33. That is, the output from one of the CVT 10 and the CVT 20 may be input to the sun gear 31 and the output from the other may be input to the ring gear 34.

  The reduction mechanism 60 transmits the driving force output from the planetary gear mechanism 30 while reversing the rotation direction and reducing the driving force. The speed reduction mechanism 60 includes a first gear 61 that is connected to the output shaft 30 a of the planetary gear mechanism 30 and rotates integrally, and a second gear 62 that meshes with the first gear 61. The second gear 62 is connected to the differential gear 6 of the drive unit 5 via the output shaft 60a, and transmits the output of the continuously variable transmission 100. The first gear 61 is formed with a smaller diameter than the second gear 62. As a result, the driving force input to the speed reduction mechanism 60 is increased and output by the amount corresponding to the reduced speed.

  The speed reduction mechanism 60 decelerates the rotation increased by the speed increase mechanism 50 and returns it to the original appropriate rotation speed. As described above, in the continuously variable transmission 100, the rotation of the engine 1 is input by being accelerated by the speed increasing mechanism 50, and the output rotation is decelerated by the speed reducing mechanism 60 and transmitted to the drive unit 5. Since the speed increasing mechanism 50 is provided, the driving force input to the continuously variable transmission 100 is reduced, so that the magnitude of the torque acting on various parts in the continuously variable transmission 100 is reduced. Therefore, durability of continuously variable transmission 100 can be improved.

  In addition, without providing the speed increasing mechanism 50 and the speed reducing mechanism 60, the driving force is directly input from the engine 1 to the positive rotation gear 42 of the reversing mechanism 40, and the driving force is output from the output shaft 30 a of the planetary gear mechanism 30 to the driving unit 5. May be output directly. In this case, since the configuration of the continuously variable transmission 100 can be simplified, the size and weight can be reduced.

  Next, the operation of the continuously variable transmission 100 will be described with reference to FIGS.

  The arrows indicated by the solid lines in FIGS. 2A to 2C indicate the rotational speeds of the sun gear 31, the planetary carrier 33, and the ring gear 34, respectively.

  As shown in FIGS. 2A to 2C, the continuously variable transmission 100 combines the rotation input from the sun gear 31 and the rotation input from the ring gear 34 and outputs it as the rotation of the planetary carrier 33. To do. In the continuously variable transmission 100, the rotational speed of the planetary carrier 33 can be adjusted steplessly by adjusting the rotational speed of the sun gear 31 with the CVT 10 and adjusting the rotational speed of the ring gear 34 with the CVT 20. It should be noted that the sun gear 31 and the ring gear 34 are such that the rotation of the engine 1 is transmitted, and therefore do not stop or rotate in the opposite direction.

  The state (a) in FIG. 2 is a state in which the transmission ratio of the CVT 10 is maximum and the transmission ratio of the CVT 20 is minimum. In this state, as shown in FIG. 3A, the sun gear 31 rotates at a low speed, and the ring gear 34 rotates at a higher speed than the sun gear 31 and in the direction opposite to the sun gear 31, whereby the planetary gear 32 is Rotate and revolve forward. Thereby, the planetary carrier 33 rotates in the forward direction by a driving force obtained by combining the rotation of the sun gear 31 and the rotation of the ring gear 34. Therefore, the vehicle moves forward.

  The state (b) in FIG. 2 is a state in which the speed ratio of the CVT 10 is made smaller and the speed ratio of the CVT 20 is made larger than the state (a) in FIG. In this state, as shown in FIG. 3B, the sun gear 31 and the ring gear 34 rotate in the reverse direction, and the speeds at the meshing portion with the planetary gear 32 become equal. As a result, the planetary carrier 33 stops rotating because the driving force obtained by combining the rotation of the sun gear 31 and the rotation of the ring gear 34 becomes zero. Therefore, the vehicle is stopped.

  The state (c) in FIG. 2 is a state in which the speed ratio of the CVT 10 is further reduced and the speed ratio of the CVT 20 is further increased as compared with the state (b) of FIG. In this state, as shown in FIG. 3C, the sun gear 31 rotates at a high speed, and the ring gear 34 rotates at a low speed compared to the sun gear 31 and in the direction opposite to the sun gear 31. Rotate and revolve in the opposite direction. Thereby, the planetary carrier 33 rotates in the opposite direction by the driving force obtained by combining the rotation of the sun gear 31 and the rotation of the ring gear 34. Therefore, the vehicle moves backward.

  As described above, in the continuously variable transmission 100, the output of the engine 1 is kept constant by adjusting the gear ratio between the CVT 10 and the CVT 20 and adjusting the rotational speed of the sun gear 31 and the rotational speed of the ring gear 34. It is possible to freely switch the vehicle forward, stop, and reverse. Therefore, there is no need to provide a reverse gear or the like for moving the vehicle backward. Since the driver only needs to operate a switch for switching to one of the forward, stop, and reverse travel modes, driving is easy.

  Further, in the continuously variable transmission 100, the speed of the vehicle during forward and backward movements can be freely adjusted by adjusting the transmission ratio between the CVT 10 and the CVT 20 while maintaining the output of the engine 1 constant. . Therefore, by using the continuously variable transmission 100, the engine 1 can be maintained at the rotational speed with the highest thermal efficiency, and fuel efficiency can be improved.

  Next, the driving force output from the planetary gear mechanism 30 will be described with reference to FIG.

  FIG. 4 schematically shows the relationship of the magnitude of the driving force in the planetary gear mechanism 30. In FIG. 4, Ts indicates the torque due to the rotation of the sun gear 31, Tr indicates the torque due to the rotation of the ring gear 34, and Tc indicates the torque output from the planetary carrier 33. Rs is the radius of the sun gear 31, and Rr is the radius of the ring gear 34.

  In the planetary gear mechanism 30, the driving force of the CVT 10 and the driving force of the CVT 20 are input as rotations in opposite directions. Therefore, the torque that acts on the planetary gear 32 by the rotation of the sun gear 31 and the torque that acts on the planetary gear 32 by the rotation of the ring gear 34 both act to rotate the planetary gear 32 in the same direction. Therefore, as shown in FIG. 4, the sum of the torque Ts due to the rotation of the sun gear 31 and the torque Tr due to the rotation of the ring gear 34 is the torque Tc output from the planetary carrier 33.

  Thus, the driving force output from the planetary carrier 33 is the sum of the driving force due to the rotation of the sun gear 31 and the driving force due to the rotation of the ring gear 34 rotating in the direction opposite to the sun gear 31. Therefore, since the driving force from the sun gear 31 and the driving force from the ring gear 34 do not cancel each other, the internal loss in the planetary gear mechanism 30 can be reduced and the transmission efficiency of the driving force can be improved.

  According to the above embodiment, the following effects are obtained.

  The driving force from the engine 1 is input to the CVT 10 and inverted and input to the CVT 20. Outputs from the CVT 10 and the CVT 20 are input to the sun gear 31 and the ring gear 34 of the planetary gear mechanism 30, respectively, and the combined driving force is output from the planetary carrier 33. Therefore, the forward, stop, and reverse travel modes can be continuously changed by adjusting the transmission ratio of CVT 10 and the transmission ratio of CVT 20.

  At this time, the driving force output from the planetary carrier 33 is the sum of the driving force due to the rotation of the sun gear 31 and the driving force due to the rotation of the ring gear 34 rotating in the direction opposite to the sun gear 31. Therefore, the transmission efficiency of the driving force in the planetary gear mechanism 30 can be improved.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  For example, the CVT 10 and the CVT 20 are belt drive type CVTs, but may be other types of CVTs such as a chain drive type and a toroidal type.

100 continuously variable transmission 1 engine (motor)
1a Output shaft 1a
3 Clutch 10 CVT (first transmission mechanism)
11 Primary pulley 12 Secondary pulley 13 Belt 20 CVT (second transmission mechanism)
21 primary pulley 22 secondary pulley 23 belt 30 planetary gear mechanism 30a output shaft 31 sun gear 32 planetary gear 33 planetary carrier 34 ring gear 40 reversing mechanism 50 speed increasing mechanism 60 speed reducing mechanism 60a output shaft

Claims (5)

A continuously variable transmission that shifts the driving force of the prime mover and outputs it to the output shaft,
A first transmission mechanism that receives a driving force from the prime mover and continuously adjusts and outputs a gear ratio;
A second speed change mechanism that reversely inputs the driving force from the prime mover and continuously adjusts and outputs the speed ratio;
An output from the first transmission mechanism and an output from the second transmission mechanism are input, and a planetary gear mechanism that combines the driving force and outputs the resultant to the output shaft, and
The planetary gear mechanism includes a sun gear that can rotate, a planetary carrier that can rotate and connect to a planetary gear that meshes with the outer periphery of the sun gear, a ring gear that meshes with the outer periphery of the planetary gear and can rotate. With
The sun gear receives an output from one of the first transmission mechanism and the second transmission mechanism, and the ring gear receives an output from the other of the first transmission mechanism and the second transmission mechanism. A continuously variable transmission in which the input and combined driving force is output from the planetary carrier.   The continuously variable transmission according to claim 1, further comprising a reversing mechanism that transmits the driving force of the prime mover to the first transmission mechanism and the second transmission mechanism as rotations in opposite directions. The first transmission mechanism and the second transmission mechanism are:
A primary pulley to which the driving force of the prime mover is input;
A secondary pulley to which driving force is transmitted by a belt suspended between the primary pulley,
The rotation in the same direction as the prime mover is input to the primary pulley of the first transmission mechanism, and the rotation in the opposite direction to the prime mover is input to the primary pulley of the second transmission mechanism. The continuously variable transmission according to Item 2.   The continuously variable transmission according to claim 2 or 3, further comprising a clutch provided between the prime mover and the reversing mechanism and capable of connecting / disconnecting transmission of driving force. A speed increasing mechanism that speeds up rotation of the output shaft of the prime mover and transmits it to the reversing mechanism;
The continuously variable transmission according to any one of claims 2 to 4, further comprising a reduction mechanism that decelerates and outputs rotation of the output shaft of the planetary gear mechanism.

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