JP2016033402A - Power split type non-stage transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power split type non-stage transmission which can improve the fuel consumption of a vehicle by improving the transfer efficiency of torque.SOLUTION: A power split type non-stage transmission 1 includes an input shaft 3, an output shaft 4, a non-stage transmission mechanism 5, a constant transmission mechanism 6, and synthetic gear mechanism 7. The transmission gear ratio of the constant transmission mechanism 6 is set such that the torque capacity safety factor of a reverse brake 24 included in the constant transmission mechanism 6 is equal to or more than a value (for example, 1.2) required at a minimum and equal to or less than a predetermined value (for example, 1.3).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power split type continuously variable transmission mounted on a vehicle.

  A vehicle such as an automobile is equipped with a transmission such as a manual transmission, an automatic transmission, or a continuously variable transmission (CVT) in order to shift engine power and transmit it to wheels.

  As a transmission, for example, a continuously variable transmission mechanism that continuously changes engine power, a gear mechanism that transmits engine power without passing through a continuously variable transmission mechanism, and a power and gear mechanism from the continuously variable transmission mechanism The thing provided with the planetary gear mechanism for synthesize | combining the motive power from is proposed.

Japanese Patent No. 4552376

  The applicant of the present application has previously proposed a transmission having such a configuration as a power split type continuously variable transmission. The power split continuously variable transmission according to this proposal includes a continuously variable transmission mechanism for continuously shifting power, a constant transmission mechanism for shifting power at a constant transmission ratio, and a continuously variable transmission mechanism. And a synthesizing gear mechanism for synthesizing the motive power and the power from the constant speed change mechanism. In the power split type continuously variable transmission, the belt transmission mode in which power is transmitted to the planetary gear mechanism only through the continuously variable transmission mechanism, and the planetary power through the continuously variable transmission mechanism and the constant transmission mechanism. It is possible to switch to the power split mode transmitted to the gear mechanism. Further, the gear included in the constant transmission mechanism is braked by the engagement of the reverse engagement element, and the power from the engine is transmitted to the planetary gear mechanism only through the continuously variable transmission mechanism, thereby moving the vehicle backward. be able to.

  The reverse engagement element is engaged only when the vehicle moves backward, and is released when the vehicle moves forward. Therefore, when the vehicle moves forward, the reverse engagement element generates drag torque, and the generation of the drag torque contributes to a decrease in torque (power) transmission efficiency in the entire transmission, and thus to deterioration of the fuel consumption of the vehicle. ing.

  An object of the present invention is to provide a power split type continuously variable transmission capable of improving the fuel efficiency of a vehicle by improving the torque transmission efficiency.

  In order to achieve the above object, a power split continuously variable transmission according to the present invention includes a continuously variable transmission mechanism for continuously changing power input to a rotating shaft, and power input to the rotating shaft. A constant speed change mechanism for shifting the power at a constant speed ratio, and a synthesizing gear mechanism for combining the power from the continuously variable transmission mechanism and the power from the constant speed change mechanism. A continuously variable transmission mode in which only the transmission mechanism is transmitted to the combining gear mechanism, and a power split mode in which power is transmitted to the combining gear mechanism through the continuously variable transmission mechanism and the constant transmission mechanism. The constant speed change mechanism is supported by the rotary shaft so as not to rotate relative to the rotary shaft, and supports a pinion gear so as to be rotatable, relative to the rotary shaft. Provided rotatably, said A split drive for transmitting power to the synthesizing gear mechanism, which is provided so as to be rotatable relative to the rotation shaft and is engaged with the pinion gear, and is integrally rotatable with the sun gear. And a reverse engagement element that is engaged / released to brake / allow rotation of the split drive gear, and the speed ratio of the constant speed change mechanism is equal to the torque capacity of the reverse engagement element. The value is set accordingly.

  According to this configuration, the torque transmission efficiency is improved as the gear ratio of the constant speed change mechanism is smaller. However, the smaller the gear ratio of the constant speed change mechanism, the larger the torque capacity required for the reverse engagement element. The torque capacity of the reverse engagement element can be increased by increasing the number of disks of the reverse engagement element. However, if the number of disks is increased, the drag torque of the reverse engagement element increases and torque transmission is achieved. Efficiency is reduced.

  Therefore, the speed ratio of the constant speed change mechanism is set to a value corresponding to the torque capacity of the reverse engagement element. As a result, the number of disks of the reverse engagement element can be kept constant, and the gear ratio of the constant speed change mechanism can be made as small as possible while ensuring the torque capacity of the reverse engagement element. As a result, it is possible to improve the torque transmission efficiency of the power split type continuously variable transmission without increasing the cost, and to improve the fuel efficiency of the vehicle by improving the torque transmission efficiency.

  According to the present invention, it is possible to improve the torque transmission efficiency of the power split continuously variable transmission without increasing the cost. As a result, the fuel efficiency of the vehicle can be improved by improving the torque transmission efficiency.

It is a skeleton figure which shows the structure of the power split type continuously variable transmission which concerns on one Embodiment of this invention. It is a figure which shows the state of the reverse brake, the low clutch, and the high brake at the time of advance of a vehicle, and reverse drive. It is a collinear diagram which shows the relationship of the rotation speed of the sun gear of a synthetic | combination gear mechanism, a carrier, and a ring gear. It is sectional drawing which shows the mechanical structure of a constant speed change mechanism, and shows only one side with respect to the axis line (rotation centerline) of an input shaft. It is a graph which shows the relationship between the transmission ratio of a constant transmission mechanism, the torque transmission efficiency E in a power division type continuously variable transmission, and the torque capacity safety factor of a reverse brake.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a skeleton diagram showing a configuration of a power split type continuously variable transmission 1 according to an embodiment of the present invention.

  The power split type continuously variable transmission 1 is mounted, for example, in an automobile using an engine as a power source in order to shift engine power and transmit it to a differential gear 2. The power split type continuously variable transmission 1 includes an input shaft 3, an output shaft 4, a continuously variable transmission mechanism 5, a constant transmission mechanism 6, and a synthesizing gear mechanism 7.

  Engine power is input to the input shaft 3.

  The output shaft 4 is provided in parallel with the input shaft 3.

  The continuously variable transmission mechanism 5 is a belt-type continuously variable transmission mechanism. The continuously variable transmission mechanism 5 includes a primary shaft 11 coupled to the input shaft 3, a secondary shaft 12 provided in parallel with the primary shaft 11, a primary pulley 13 supported by the primary shaft 11 so as not to rotate relative thereto, A secondary pulley 14 supported on the shaft 12 so as not to rotate relative to the shaft 12 and a belt 15 wound around the primary pulley 13 and the secondary pulley 14 are provided.

  The constant speed change mechanism 6 includes a planetary gear mechanism 21, a split drive gear 22, a high brake 23, and a reverse brake 24.

  The planetary gear mechanism 21 includes a carrier 25, a sun gear 26, and a ring gear 27. The carrier 25 is supported by the input shaft 3 so as not to be relatively rotatable. The carrier 25 supports a plurality of pinion gears 28 so as to be rotatable. The plurality of pinion gears 28 are arranged at equal angular intervals on the circumference. The sun gear 26 is externally fitted to the input shaft 3 so as to be relatively rotatable, and meshes with each pinion gear 28 from the inner side in the rotational radial direction of the input shaft 3. The ring gear 27 has an annular shape that surrounds the periphery of the carrier 25, and meshes with each pinion gear 28 from the outside in the rotational radial direction of the input shaft 3.

  The split drive gear 22 is provided so as to be rotatable integrally with the sun gear 26.

  The high brake 23 is switched between an engaged state (on) in which the ring gear 27 is braked and a released state (off) in which the ring gear 27 is allowed to rotate.

  The reverse brake 24 is switched between an engaged state (on) in which the split drive gear 22 (sun gear 26) is braked and a released state (off) in which the split drive gear 22 is allowed to rotate.

  The synthesizing gear mechanism 7 has a configuration of a planetary gear mechanism. That is, the synthesizing gear mechanism 7 includes a carrier 31, a sun gear 32, and a ring gear 33. The carrier 31 is provided to be rotatable relative to the secondary shaft 12 of the continuously variable transmission mechanism 5. The carrier 31 supports a plurality of pinion gears 34 in a rotatable manner. The plurality of pinion gears 34 are arranged at equal angular intervals on the circumference. The sun gear 32 is supported by the secondary shaft 12 so as not to be relatively rotatable, and meshes with each pinion gear 34 from the inner side in the rotational radial direction of the secondary shaft 12. The ring gear 33 has an annular shape surrounding the periphery of the carrier 31, and meshes with each pinion gear 34 from the outer side in the rotational radial direction of the secondary shaft 12. Further, the ring gear 33 is provided so as to be able to rotate integrally with the output shaft 4.

  The synthesizing gear mechanism 7 includes a low clutch 35. The low clutch 35 is switched between an engaged state (ON) in which the output shaft 4 and the secondary shaft 12 are directly connected and a released state (OFF) in which the direct connection is released.

  The constant speed change mechanism 6 includes a split driven gear 36 that is provided so as to rotate integrally with the carrier 31, and an idle gear 37 that meshes with the split drive gear 22 and the split driven gear 36.

  Further, the power split type continuously variable transmission 1 includes an idle mechanism 8. The idle mechanism 8 includes an idle shaft 41 provided in parallel with the output shaft 4, and a first idle gear 42 and a second idle gear 43 that are supported by the idle shaft 41 so as not to rotate relative to each other. An output gear 44 is supported on the output shaft 4 so as not to be relatively rotatable. The output gear 44 and the first idle gear 42 are engaged with each other. The second idle gear 43 meshes with a ring gear 45 provided in the differential gear 2.

  FIG. 2 is a diagram showing the states of the high brake 23, the reverse brake 24, and the low clutch 35 when the vehicle is moving forward and backward. In FIG. 2, “◯” indicates that the high brake 23, the reverse brake 24, and the low clutch 35 are engaged.

  The power split continuously variable transmission 1 has a belt mode (continuously variable transmission mode) and a split mode (power split mode) as power transmission modes when the vehicle moves forward.

  In the belt mode, the high brake 23 and the reverse brake 24 are released. Then, the low clutch 35 is engaged. Thereby, the output shaft 4 and the secondary shaft 12 are directly connected.

  The power input to the input shaft 3 is transmitted to the primary shaft 11 of the continuously variable transmission mechanism 5 to rotate the primary shaft 11 and the primary pulley 13. The rotation of the primary pulley 13 is transmitted to the secondary pulley 14 via the belt 15 to rotate the secondary pulley 14 and the secondary shaft 12. Since the low clutch 35 is engaged, the output shaft 4 rotates integrally with the secondary shaft 12. The rotation of the output shaft 4 is transmitted to the ring gear 45 of the differential gear 2 via the output gear 44, the first idle gear 42, the idle shaft 41 and the second idle gear 43. As a result, the drive shafts 51 and 52 of the vehicle rotate in the forward direction.

  The transmission ratio of the constant transmission mechanism 6 is set to the same transmission ratio as the minimum transmission ratio of the continuously variable transmission mechanism 5. When the gear ratio of the continuously variable transmission mechanism 5 is changed to the minimum gear ratio according to the vehicle speed, the power transmission mode is switched from the belt mode to the split mode. In the split mode, the high brake 23 is engaged, and the reverse brake 24 and the low clutch 35 are released. When the high brake 23 is engaged, the ring gear 27 of the constant speed change mechanism 6 is braked. Further, when the low clutch 35 is released, the direct connection between the output shaft 4 and the secondary shaft 12 is released.

  The power input to the input shaft 3 is transmitted to the primary shaft 11 of the continuously variable transmission mechanism 5 to rotate the primary shaft 11 and the primary pulley 13. The rotation of the primary pulley 13 is transmitted to the secondary pulley 14 via the belt 15 to rotate the secondary pulley 14 and the secondary shaft 12. As the secondary shaft 12 rotates, the sun gear 32 of the synthesizing gear mechanism 7 rotates.

  Since the ring gear 27 of the constant speed change mechanism 6 is braked, the power input to the input shaft 3 revolves the carrier 25 of the constant speed change mechanism 6 and rotates the pinion gear 28 held by the carrier 25. Let As the pinion gear 28 rotates, power is input from the pinion gear 28 to the sun gear 26. As a result, the pinion gear 28 and the split drive gear 22 rotate. The rotation of the split drive gear 22 is transmitted to the split driven gear 36 via the idle gear 37 of the constant speed change mechanism 6 to rotate the split driven gear 36 and the carrier 31.

  Since the speed ratio of the constant speed change mechanism 6 is the same as the minimum speed ratio of the continuously variable speed change mechanism 5, immediately after switching from the belt mode to the split mode, the carrier 31, sun gear 32 and ring gear 33 of the synthesizing gear mechanism 7 Rotates at the same speed. Then, the output shaft 4 rotates integrally with the ring gear 33. The rotation of the output shaft 4 is transmitted to the ring gear 45 of the differential gear 2 via the output gear 44, the first idle gear 42, the idle shaft 41 and the second idle gear 43. As a result, the drive shafts 51 and 52 of the vehicle rotate in the forward direction.

  Since the speed ratio of the constant speed change mechanism 6 is fixed at the same speed ratio as the minimum speed ratio of the continuously variable speed change mechanism 5, the rotation of the carrier 31 of the synthesizing gear mechanism 7 is held at a constant speed in the split mode. Therefore, as shown in FIG. 3, when the speed ratio of the continuously variable transmission mechanism 5 is increased, the rotational speed of the sun gear 32 (secondary shaft 12) decreases, and accordingly, the rotational speed of the ring gear (output shaft 4). Goes up. Therefore, the power split type continuously variable transmission 1 can have a large gear ratio range.

  Further, during reverse travel, the high brake 23 and the low clutch 35 are released. Then, the reverse brake 24 is engaged. As a result, the split drive gear 22 (sun gear 26) is braked. Due to the braking of the split drive gear 22, the idle gear 37 of the constant speed change mechanism 6 becomes non-rotatable and the split driven gear 36 and the carrier 31 become non-rotatable.

  The power input to the input shaft 3 is transmitted to the primary shaft 11 of the continuously variable transmission mechanism 5 to rotate the primary shaft 11 and the primary pulley 13. The rotation of the primary pulley 13 is transmitted to the secondary pulley 14 via the belt 15 to rotate the secondary pulley 14 and the secondary shaft 12. As the secondary shaft 12 rotates, the sun gear 32 of the synthesizing gear mechanism 7 rotates. Since the carrier 31 cannot rotate, when the sun gear 32 rotates, the ring gear 33 rotates in the direction opposite to the sun gear 32. The rotation direction of the ring gear 33 is opposite to the rotation direction of the ring gear 33 in the belt mode and the split mode. Then, the output shaft 4 rotates integrally with the ring gear 33. The rotation of the output shaft 4 is transmitted to the ring gear 45 of the differential gear 2 via the output gear 44, the first idle gear 42, the idle shaft 41 and the second idle gear 43. As a result, the drive shafts 51 and 52 of the vehicle rotate in the reverse direction.

  FIG. 4 is a cross-sectional view showing the mechanical configuration of the constant speed change mechanism 6 and shows only one side with respect to the axis (rotation center line) C of the input shaft 3.

  The carrier 25 of the planetary gear mechanism 21 is integrally provided with an inner peripheral portion 61 and a flange portion 62. The inner peripheral portion 61 is externally fitted to the input shaft 3 and is provided on the input shaft 3 so as not to be relatively rotatable. The flange portion 62 projects from the inner peripheral portion 61 to the outside in the rotational radial direction of the input shaft 3. A gear support shaft 63 extending in parallel with the rotation center line C is provided at the outer peripheral end of the flange portion 62, and the pinion gear 28 is rotatably supported by the gear support shaft 63.

  The sun gear 26 is integrally provided with an outer fitting portion 64 and a gear portion 65. The outer fitting portion 64 is fitted on the input shaft 3 so as to be relatively rotatable. The gear portion 65 protrudes toward the pinion gear 28 from the end of the outer fitting portion 64 on the continuously variable transmission mechanism 5 side. Gear teeth 67 that mesh with the gear teeth 66 of the pinion gear 28 are formed on the surface of the gear portion 65 that faces the pinion gear 28.

  In the following, the continuously variable transmission mechanism 5 side is defined as “left side”, and the opposite side is defined as “right side”, and “left and right” are used for explanation of directions and the like.

  The ring gear 27 includes an annular portion 68 and a gear portion 69. The annular part 68 surrounds the periphery of the input shaft 3 with a space therebetween and extends in the rotational radial direction. The gear portion 69 extends from the outer peripheral end of the annular portion 68 to the right side to a position facing the pinion gear 28 and the input shaft 3 in the rotational radial direction. Gear teeth 70 that mesh with the gear teeth 66 of the pinion gear 28 are formed on the surface of the gear portion 69 that faces the pinion gear 28.

  The split drive gear 22 is fixed to the right end portion of the outer fitting portion 64 of the sun gear 26 in an outer fitting state.

  The reverse brake 24 includes a brake hub 71. The brake hub 71 is fixed to the split drive gear 22, and a disc portion 72 that extends in the rotational radial direction of the input shaft 3 and a cylindrical portion 73 that extends parallel to the rotation center line C from the outer peripheral end of the disc portion 72 are integrated. Have. A plurality of disc-shaped brake discs 74 are arranged on the outer periphery of the cylindrical portion 73 at intervals, and the inner peripheral portion of each brake disc 74 is spline-fitted to the cylindrical portion 73.

  A plurality of annular plate-like brake plates 75 are arranged on the outer periphery of the cylindrical portion 73 so as to be alternately arranged in the direction along the brake disc 74 and the rotation center line C. The outer periphery of each brake plate 75 is spline-fitted to a case 76 that houses the constant speed change mechanism 6.

  A piston 77 is provided on the right side of the brake hub 71 so as to be movable in a direction along the rotation center line C. The hydraulic pressure is supplied to the piston 77, the piston 77 moves to the left side, and the piston 77 presses the brake plate 75, so that the brake plate 75 and the brake disc 74 come into pressure contact. As a result, the reverse brake 24 is engaged and the split drive gear 22 is braked. When the hydraulic pressure acting on the piston 77 is released, the urging force of the return spring 78 moves the piston 77 to the right, and the pressure contact state between the brake plate 75 and the brake disc 74 is released. As a result, the reverse brake 24 is released and the braking of the split drive gear 22 is released.

  FIG. 5 is a graph showing the relationship between the transmission ratio of the constant transmission mechanism 6, the torque transmission efficiency E in the power split type continuously variable transmission 1, and the torque capacity safety factor of the reverse brake 24.

  When the vehicle moves forward, the reverse brake 24 is released, and a drag torque Tx is generated in the released reverse brake 24.

  The torque transmission efficiency E in the power split type continuously variable transmission 1 is expressed by the following equation (1) where Tin is the input torque, γ is the transmission ratio of the continuously variable transmission mechanism 5, and i is the transmission ratio of the constant transmission mechanism 6. ).

    E = {(Tin−i · Tx / γ) / Tin} × 100 (%) (1)

  From this equation (1), it can be seen that the smaller the speed ratio i of the constant speed change mechanism 6 is, the more the torque transmission efficiency E is improved. However, the smaller the gear ratio of the constant speed change mechanism 6, the larger the torque capacity required for the reverse brake 24, and the lower the torque capacity safety factor of the reverse brake 24. The torque capacity safety factor is a ratio of the maximum torque capacity of the reverse brake 24 to the maximum value of torque input to the reverse brake 24.

  By increasing the number of brake discs 74 (the number of discs) provided in the reverse brake 24, the torque capacity of the reverse brake 24 can be increased. However, if the number of discs of the reverse brake 24 is increased, the drag torque Tx of the reverse brake 24 increases, so that the torque transmission efficiency E in the power split type continuously variable transmission 1 decreases.

  From the above, the torque transmission efficiency E and the torque capacity safety factor of the reverse brake 24 in the power split type continuously variable transmission 1 have the relationship shown in FIG. Have.

  Therefore, in the power split type continuously variable transmission 1, the torque capacity safety of the reverse brake 24 is within the range of the speed ratio of the constant speed change mechanism 6 corresponding to the number of discs of the reverse brake 24 based on the relationship shown in FIG. The constant speed change mechanism 6 (specifically, the split drive gear 22 is set so that the ratio is a minimum required value (necessary safety factor, for example, 1.2) or more and a predetermined value (for example, 1.3) or less. The gear ratio of the split driven gear 36 and the idle gear 37), that is, the split gear ratio is set.

  As a result, the number of discs of the reverse brake 24 can be kept constant, and the gear ratio of the constant speed change mechanism 6 can be made as small as possible while ensuring the torque capacity of the reverse brake 24. As a result, the torque transmission efficiency of the power split type continuously variable transmission 1 can be improved without increasing the cost. As a result, the fuel efficiency of the vehicle can be improved by improving the torque transmission efficiency.

  As mentioned above, although one Embodiment of this invention was described, it is possible to give a various design change to the above-mentioned structure in the range of the matter described in the claim.

DESCRIPTION OF SYMBOLS 1 Power split type continuously variable transmission 5 Continuously variable transmission mechanism 6 Constant transmission mechanism 7 Composition gear mechanism 22 Split drive gear 24 Reverse brake (reverse engagement element)
25 Carrier 26 Sun gear 27 Ring gear 28 Pinion gear

Claims (1)

From the continuously variable transmission mechanism for steplessly shifting the power input to the rotating shaft, the constant transmission mechanism for shifting the power input to the rotating shaft at a constant gear ratio, and the continuously variable transmission mechanism. A continuously variable transmission mode in which power is transmitted to the synthesizing gear mechanism only through the continuously variable transmission mechanism. A power split type continuously variable transmission configured to be switchable to a power split mode in which power is transmitted to the synthesizing gear mechanism via the continuously variable transmission mechanism and the constant speed change mechanism,
The constant speed change mechanism includes:
A carrier that is supported relative to the rotating shaft so as not to rotate relative to the rotating shaft, and that rotatably supports the pinion gear;
A sun gear provided so as to be relatively rotatable with the rotation shaft and meshing with the pinion gear;
A ring gear provided so as to be rotatable relative to the rotating shaft and meshing with the pinion gear;
A split drive gear provided so as to be integrally rotatable with the sun gear, and for transmitting power to the synthesizing gear mechanism;
A reverse engagement element engaged / released to brake / permit rotation of the split drive gear,
The power split type continuously variable transmission, wherein a speed ratio of the constant speed change mechanism is set to a value corresponding to a torque capacity of the reverse engagement element.

Images