JP6552382B2 - Power split type continuously variable transmission - Google Patents

Description

  The present invention relates to a power split continuously variable transmission capable of dividing power input to an input shaft (input shaft) into two systems and transmitting the split power to an output shaft (output shaft).

  As a transmission mounted on a vehicle such as an automobile, there is a continuously variable transmission mechanism for continuously changing the power of the engine, a gear mechanism for transmitting the power of the engine without passing through the continuously variable transmission mechanism, and a continuously variable transmission mechanism It has been proposed to have a planetary gear mechanism for combining the power from the gear and the power from the gear mechanism. In this transmission, the power from the engine can be divided into the continuously variable transmission mechanism and the gear mechanism, and each divided power can be synthesized by the planetary gear mechanism and transmitted to the wheels.

JP, 2004-176890, A

  The applicant has also proposed a transmission capable of dividing and transmitting the power of the drive source into two systems as a power split type continuously variable transmission.

  The power split type continuously variable transmission according to this proposal includes a continuously variable transmission mechanism, a split transmission mechanism, and a planetary gear mechanism. The continuously variable transmission mechanism has the same configuration as a known belt-type continuously variable transmission (CVT). The power of the engine input to the input shaft is transmitted to the primary shaft of the continuously variable transmission mechanism. The secondary shaft of the continuously variable transmission mechanism is connected to the sun gear of the planetary gear mechanism. The split transmission mechanism includes a split drive gear that transmits / shuts off the power of the input shaft, and a split driven gear that forms a gear train with the split drive gear and rotates integrally with the carrier of the planetary gear mechanism. An output shaft is connected to the ring gear of the planetary gear mechanism. The rotation of the output shaft is transmitted to the differential gear and transmitted from the differential gear to the left and right drive wheels.

  The power split type continuously variable transmission has a belt mode and a split mode as power transmission modes.

  In the belt mode, the sun gear and the ring gear of the planetary gear mechanism are directly connected. Further, by interrupting the transmission of power from the input shaft to the split drive gear, the split drive gear is brought into free rotation (free), and the carrier of the planetary gear mechanism is brought into free rotation. Therefore, the sun gear and the ring gear rotate integrally and the output shaft rotates integrally with the ring gear by the power output from the continuously variable transmission mechanism. Therefore, in the belt mode, the gear ratio (unit gear ratio) of the power split continuously variable transmission matches the gear ratio (belt gear ratio) of the continuously variable transmission mechanism.

  In the split mode, the direct connection between the sun gear and the ring gear of the planetary gear mechanism is released, and the ring gear is braked. Therefore, the sun gear is rotated by the power output from the continuously variable transmission mechanism. On the other hand, power is transmitted from the input shaft to the split drive gear, and the power is shifted from the split drive gear through the split driven gear at a constant gear ratio (split gear ratio) and input to the carrier of the planetary gear mechanism. . Therefore, in the split mode, the larger the belt speed ratio, the smaller the unit speed ratio, and a speed ratio that is less than or equal to the split speed ratio can be realized.

  FIG. 6 is a graph showing the relationship between the transmission ratio and the transmission efficiency of the power split continuously variable transmission.

  In the split mode, part of the power input to the input shaft is transmitted to the output shaft through a gear train including a split drive gear and a split driven gear. Therefore, in split mode, as compared with belt mode at the same belt transmission ratio, the power transmitted to the continuously variable transmission mechanism having lower transmission efficiency than the gear train is lower, so as shown in FIG. The transmission efficiency (unit efficiency) of the continuously variable transmission is good.

  The continuously variable transmission mechanism has a configuration in which an endless belt is wound around a primary pulley supported by a primary shaft and a secondary pulley supported by a secondary shaft. In this belt-type continuously variable transmission mechanism, the transmission efficiency is best when the difference between the belt winding diameter of the primary pulley and the belt winding diameter of the secondary pulley is small, that is, when the belt gear ratio is around 1. The transmission efficiency decreases as the belt speed ratio approaches from 1 to the maximum speed ratio or the minimum speed ratio. Therefore, as shown in FIG. 6, the power split type continuously variable transmission has the best unit efficiency with the belt transmission ratio being close to 1 in each of the power transmission modes of the belt mode and the split mode. The unit efficiency deteriorates as the ratio approaches the maximum speed ratio or the minimum speed ratio.

  Therefore, in the unit gear ratio of the power split type continuously variable transmission, a region where the unit efficiency is bad near the split gear ratio (switching point between the belt mode and the split mode) (hereinafter referred to as "valley of unit efficiency"). Exists.

  An object of the present invention is to provide a power split type continuously variable transmission that can avoid the use of valleys of unit efficiency.

  In order to achieve the above object, a power split type continuously variable transmission according to the present invention comprises: a belt type continuously variable transmission mechanism which continuously shifts power input to an input shaft by changing a belt transmission ratio; A split transmission mechanism that shifts the power input to the shaft at a constant split gear ratio, and an output gear mechanism that outputs the power to the output shaft, and the power input to the input shaft passes through the continuously variable transmission mechanism. The power split is selectively switched between the belt mode transmitted to the output gear mechanism and the split mode in which the power input to the input shaft is transmitted to the output gear mechanism via the continuously variable transmission mechanism and the split transmission mechanism. Continuously variable transmission, wherein the continuously variable transmission mechanism has a configuration in which a belt is wound around a primary pulley and a secondary pulley, and the primary pulley and the se At least one of the pulleys is a fixed sheave, a movable sheave disposed opposite to the fixed sheave with a belt interposed therebetween, and a movable sheave that is movable in a direction facing the fixed sheave, and a movable sheave that moves away from the fixed sheave. A stopper for stopping the movement of the movable sheave at a position where a belt transmission ratio corresponding to a predetermined value larger than the split transmission ratio and smaller than 1 is obtained.

  According to this configuration, in the belt mode, the power input to the input shaft is transmitted to the output gear mechanism via the continuously variable transmission mechanism, and the power passing through the continuously variable transmission mechanism is output to the output shaft. . In the split mode, the power input to the input shaft is transmitted to the output gear mechanism via both the continuously variable transmission mechanism and the split transmission mechanism, and the power passing through the continuously variable transmission mechanism and the power passing through the split transmission mechanism. Are combined by the output gear mechanism and output to the output shaft.

  When the movable sheave of the secondary pulley moves away from the fixed sheave, the diameter at which the belt is wound around the secondary pulley decreases, and the belt transmission ratio decreases. As the movement of the movable sheave proceeds, the movable sheave comes into contact with the stopper, and further movement of the movable sheave is prevented. At this time, the belt transmission ratio becomes minimum, and the minimum belt transmission ratio coincides with a predetermined value which is larger than the split transmission ratio of the split transmission mechanism and less than one.

  As a result, it is possible to prohibit the belt transmission ratio from becoming smaller than a predetermined value, and to avoid the use of unit efficiency valleys.

  The secondary pulley may further include a cylinder fixedly provided in the moving direction of the movable sheave on the opposite side of the movable sheave to the movable sheave, and the stopper may be formed separately from the cylinder.

  In this case, by changing the position or shape of the stopper, the position of the movable sheave when the movable sheave abuts the stopper can be changed, and the minimum value of the belt transmission ratio can be changed. Therefore, even if the split transmission ratio of the split transmission mechanism is changed, the minimum value of the belt transmission ratio is set to a predetermined value larger than the split transmission ratio by changing the position or the shape of the stopper without changing the shape of the cylinder. Can be matched. Therefore, the power split continuously variable transmission can be provided with versatility that can be mounted on various vehicle types.

  According to the present invention, when the movable sheave moving to the side away from the fixed sheave abuts on the stopper, it is possible to inhibit the belt transmission ratio from becoming smaller than a predetermined value larger than the split transmission ratio. Therefore, the use of the valley of unit efficiency can be avoided, and the fuel efficiency of the vehicle equipped with the power split type continuously variable transmission can be improved.

1 is a skeleton diagram showing a configuration of a drive system of a vehicle equipped with a power split type continuously variable transmission according to an embodiment of the present invention. It is a figure which shows the state of the belt mode clutch, reverse brake, and split mode brake at the time of forward movement and reverse travel of the vehicle. It is a collinear diagram which shows the relationship of the rotation speed (rotation speed) of the sun gear of a planetary gear mechanism for an output, a carrier, and a ring gear. It is sectional drawing which shows the structure of a secondary pulley, and shows a state when the gear ratio of a continuously variable transmission mechanism is the maximum. It is sectional drawing which shows the structure of a secondary pulley, and shows a state when the gear ratio of a continuously variable transmission mechanism is the minimum. It is a graph which shows the relationship between the unit gear ratio and unit efficiency of a power division type continuously variable transmission. It is a graph which shows the relationship between the unit gear ratio and unit efficiency of the conventional power division type continuously variable transmission.

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

<Configuration of drive system>
FIG. 1 is a skeleton diagram showing a configuration of a drive system of a vehicle 1 on which a power split type continuously variable transmission 4 according to an embodiment of the present invention is mounted.

  The vehicle 1 is an automobile having an engine 2 as a drive source. The output of the engine 2 is transmitted to driving wheels (for example, left and right front wheels) of the vehicle 1 via the torque converter 3 and the power split type continuously variable transmission 4.

  The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lockup clutch 33. The output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 31, and the pump impeller 31 is integrally rotatably provided around the same rotation axis as the E / G output shaft. ing. The turbine runner 32 is rotatably provided about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to connect / disconnect the pump impeller 31 and the turbine runner 32 directly. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly coupled, and when the lockup clutch 33 is released, the pump impeller 31 and the turbine runner 32 are separated.

  When the E / G output shaft is rotated in a state where the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, a flow of oil from the pump impeller 31 toward the turbine runner 32 is generated. This oil flow is received by the turbine runner 32 and the turbine runner 32 rotates. At this time, an amplification action of the torque converter 3 occurs, and a power larger than the power (torque) of the E / G output shaft is generated in the turbine runner 32.

  With the lockup clutch 33 engaged, when the E / G output shaft is rotated, the E / G output shaft, the pump impeller 31 and the turbine runner 32 rotate integrally.

  The power split type continuously variable transmission 4 includes an input shaft 41, an output shaft 42, a continuously variable transmission mechanism 43, an output planetary gear mechanism 44 and a split transmission mechanism 45.

  The input shaft 41 is connected to the turbine runner 32 of the torque converter 3 and provided integrally rotatably around the same rotation axis as the turbine runner 32.

  The output shaft 42 is provided in parallel with the input shaft 41. An output gear 46 is supported on the output shaft 42 so as not to be relatively rotatable.

  The continuously variable transmission mechanism 43 has the same configuration as a known belt-type continuously variable transmission (CVT). More specifically, the continuously variable transmission mechanism 43 includes a primary shaft 51, a secondary shaft 52 provided parallel to the primary shaft 51, a primary pulley 53 supported against relative rotation by the primary shaft 51, and a secondary shaft 52. , And a belt 55 wound around the primary pulley 53 and the secondary pulley 54.

  Primary pulley 53 is disposed opposite to fixed sheave 61 fixed to primary shaft 51 and fixed sheave 61 with belt 55 interposed therebetween, and movable sheave supported on primary shaft 51 so as to be movable in the axial direction and to be relatively non-rotatable. And 62. A cylinder 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 from the fixed sheave 61, and a piston chamber (oil chamber) 64 is formed between the movable sheave 62 and the cylinder 63. Yes.

  Secondary pulley 54 is disposed opposite to fixed sheave 65 fixed to secondary shaft 52 and fixed sheave 65 with belt 55 interposed therebetween, and movable sheave supported on secondary shaft 52 so as to be movable in the axial direction and to be relatively non-rotatable. It has 66 and. A cylinder 67 fixed to the secondary shaft 52 is provided on the opposite side of the movable sheave 66 with respect to the fixed sheave 65, and a piston chamber (oil chamber) 68 is formed between the movable sheave 66 and the cylinder 67. Yes.

  In the continuously variable transmission mechanism 43, the oil pressure supplied to the piston chambers 64 and 68 of the primary pulley 53 and the secondary pulley 54 is controlled, and the groove widths of the primary pulley 53 and the secondary pulley 54 are changed. The belt transmission ratio, which is the transmission ratio in the step transmission mechanism 43, is continuously changed steplessly.

  Specifically, when the belt transmission ratio is lowered, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is increased. As a result, the movable sheave 62 of the primary pulley 53 moves toward the fixed sheave 61, and the distance (groove width) between the fixed sheave 61 and the movable sheave 62 decreases. Along with this, the winding diameter of the belt 55 with respect to the primary pulley 53 is increased, and the distance (groove width) between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is increased. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is reduced, and the belt transmission ratio is reduced.

  When the belt transmission ratio is increased, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is decreased. As a result, the thrust of secondary pulley 54 relative to belt 55 becomes larger than the thrust of primary pulley 53 relative to belt 55, and the distance between fixed sheave 65 and movable sheave 66 of secondary pulley 54 becomes smaller, and fixed sheave 61 and movable sheave The distance to 62 increases. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is increased, and the belt transmission ratio is increased.

  On the other hand, the thrust of the primary pulley 53 and the secondary pulley 54 needs to be large enough to prevent slippage between the primary pulley 53 and the secondary pulley 54 and the belt 55. Therefore, the hydraulic pressure (oil amount) supplied to the piston chambers 64 and 68 of the primary pulley 53 and the secondary pulley 54 is controlled so that a thrust according to the magnitude of the torque input to the primary shaft 51 is obtained.

  The output planetary gear mechanism 44 includes a sun gear 71, a carrier 72, and a ring gear 73. The sun gear 71 is non-rotatably supported by the secondary shaft 52 (provided so as to be integrally rotatable about the same rotation axis as the secondary shaft 52). The carrier 72 is fitted on the output shaft 42 so as to be relatively rotatable. The carrier 72 supports a plurality of pinion gears 74 in a rotatable manner. The plurality of pinion gears 74 are arranged on the circumference and mesh with the sun gear 71. The ring gear 73 has an annular shape that collectively surrounds a plurality of pinion gears 74, and meshes with each pinion gear 74 from the outside in the rotational radial direction of the secondary shaft 52. Further, an output shaft 42 is connected to the ring gear 73, and the ring gear 73 is integrally rotatably provided around the same rotation axis as the output shaft 42.

  The split transmission mechanism 45 includes a speed increasing planetary gear mechanism 81, a split drive gear 82, a split driven gear 83, and an idle gear 84.

  The speed increasing planetary gear mechanism 81 includes a sun gear 85, a carrier 86, and a ring gear 87. The sun gear 85 is fitted on the input shaft 41 so as to be relatively rotatable. The carrier 86 is supported by the input shaft 41 so as not to rotate relative to the input shaft 41. The carrier 86 rotatably supports a plurality of pinion gears 88. The plurality of pinion gears 88 are arranged on the circumference and mesh with the sun gear 85. The ring gear 87 has an annular shape that collectively surrounds a plurality of pinion gears 88, and meshes with each pinion gear 88 from the outside in the rotational radial direction of the input shaft 41.

  The split drive gear 82 is provided so as to be integrally rotatable with the sun gear 85 of the speed increasing planetary gear mechanism 81.

  The split driven gear 83 is provided so as to rotate integrally with the carrier 72 of the output planetary gear mechanism 44.

  The idle gear 84 meshes with the split drive gear 82 and the split driven gear 83.

  The power split type continuously variable transmission 4 includes an output gear mechanism 91 that transmits the rotation of the output gear 46 to the differential gear 5. The output gear mechanism 91 includes an output idle shaft 92 provided in parallel with the output shaft 42, a first output idle gear 93 that is supported by the output idle shaft 92 so as not to rotate relative to the output gear 46, and an output It includes a second output idle gear 94 supported on the idle shaft 92 so as to be relatively non-rotatable and meshing with the differential gear 5 (the input gear of the differential gear 5).

  The power split type continuously variable transmission 4 includes a belt mode clutch C1, a reverse brake B1, and a split mode brake B2.

  The belt mode clutch C1 is switched between an engaged state (on) in which the output shaft 42 and the secondary shaft 52 are directly coupled (integrally rotatably coupled) and a released state (off) in which the direct coupling is released.

  The reverse brake B <b> 1 is switched between an engagement state (ON) for braking the split drive gear 82 (the carrier 72 of the output planetary gear mechanism 44) and a release state (OFF) allowing the rotation of the split drive gear 82.

  The split mode brake B2 is switched to an engaged state (on) in which the ring gear 87 of the speed increasing planetary gear mechanism 81 is braked (on) and a released state (off) in which the ring gear 87 is allowed to rotate.

<Power transmission mode>
FIG. 2 is a view showing the states of the belt mode clutch C1, the reverse brake B1 and the split mode brake B2 when the vehicle 1 is moving forward and backward. FIG. 3 is a collinear diagram showing the relationship between the rotational speeds (rotational speeds) of the sun gear 71, the carrier 72 and the ring gear 73 of the output planetary gear mechanism 44. As shown in FIG.

  In FIG. 2, "o" indicates that the belt mode clutch C1, the reverse brake B1 and the split mode brake B2 are in the engaged state. “X” indicates that the belt mode clutch C1, the reverse brake B1, and the split mode brake B2 are in a released state.

  The power split type continuously variable transmission 4 has a belt mode and a split mode as a power transmission mode in a forward (drive) range for advancing the vehicle 1.

  In the belt mode, as shown in FIG. 2, the belt mode clutch C1 is engaged. Thereby, the output shaft 42 and the secondary shaft 52 are directly connected. Further, the reverse brake B1 and the split mode brake B2 are released. In a state where the reverse brake B1 is released, the split drive gear 82, the split driven gear 83 and the idle gear 84 of the split transmission mechanism 45, and the carrier 72 of the output planetary gear mechanism 44 are free (in a freely rotating state). When the split mode brake B2 is released, the ring gear 87 of the speed increasing planetary gear mechanism 81 of the split transmission mechanism 45 is free.

  The power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 and causes the primary shaft 51 and the primary pulley 53 to rotate. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. Since the output shaft 42 and the secondary shaft 52 are directly connected, the output shaft 42 rotates integrally with the secondary shaft 52. Therefore, in the belt mode, as shown in FIG. 3, the unit gear ratio which is the gear ratio of the entire power split type continuously variable transmission 4 matches the belt gear ratio.

  In the split mode, as shown in FIG. 2, the split mode brake B2 is engaged. As a result, the ring gear 87 of the speed increasing planetary gear mechanism 81 of the split transmission mechanism 45 is braked. Further, the belt mode clutch C1 and the reverse brake B1 are released. When the belt mode clutch C1 is released, the direct connection between the output shaft 42 and the secondary shaft 52 is released.

  Part of the power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43, and causes the primary shaft 51 and the primary pulley 53 to rotate. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. The sun gear 71 of the output planetary gear mechanism 44 is rotated by the rotation of the secondary shaft 52.

  Further, since the ring gear 87 of the split transmission mechanism 45 is braked, part of the power input to the input shaft 41 causes the carrier 86 of the split transmission mechanism 45 to revolve and the pinion gear held by the carrier 86. Rotate 88. As the pinion gear 88 rotates, power is input from the pinion gear 88 to the sun gear 85. As a result, the split drive gear 82 rotates. The rotation of the split drive gear 82 is transmitted to the split driven gear 83 via the idle gear 84 and rotates the carrier 72 of the split driven gear 83 and the output planetary gear mechanism 44.

  Since the split transmission ratio, which is the transmission ratio of the split transmission mechanism 45, is constant and unchanged (fixed), in the split mode, if the power input to the input shaft 41 is constant, the carrier of the output planetary gear mechanism 44 The rotation of 72 is maintained at a constant speed. Therefore, when the belt speed ratio is increased, the rotational speed of the sun gear 71 of the output planetary gear mechanism 44 decreases, so that the ring gear 73 (output shaft 42) of the output planetary gear mechanism 44 as shown by a broken line in FIG. ) Will increase. As a result, in the split mode, the unit transmission ratio decreases as the belt transmission ratio increases.

  The rotation of the output shaft 42 in the belt mode and the split mode is transmitted to the differential gear 5 via the output gear 46 and the output gear mechanism 91. Thereby, the drive shafts 6 and 7 of the vehicle 1 rotate in the forward direction.

  In the reverse range for reversing the vehicle 1, as shown in FIG. 2, the belt mode clutch C1 and the split mode brake B2 are released. Then, the reverse brake B1 is engaged. As a result, the split drive gear 82 is braked. Due to the braking of the split drive gear 82, the idle gear 84 of the split transmission mechanism 45 cannot be rotated, and further, the split driven gear 83 of the split transmission mechanism 45 and the carrier 72 of the output planetary gear mechanism 44 cannot be rotated.

  The power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 to rotate the primary shaft 51 and the primary pulley 53. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. The sun gear 71 of the output planetary gear mechanism 44 is rotated by the rotation of the secondary shaft 52. Since the carrier 72 cannot rotate, when the sun gear 71 rotates as shown by a two-dot chain line in FIG. 3, the ring gear 73 rotates in the opposite direction to the sun gear 71. The rotational direction of the ring gear 73 is opposite to the rotational direction of the ring gear 73 in the forward range (belt mode and split mode). Then, the output shaft 42 rotates integrally with the ring gear 73. The rotation of the output shaft 42 is transmitted to the differential gear 5 via the output gear 46 and the output gear mechanism 91. As a result, the drive shafts 6 and 7 of the vehicle 1 rotate in the reverse direction.

<Secondary pulley>
4A and 4B are cross-sectional views showing the configuration of secondary pulley 54. FIG.

  The stationary sheave 65 of the secondary pulley 54 is integrally formed with the secondary shaft 52, and radially protrudes from the secondary shaft 52 in a hook shape. The fixed sheave 65 has a clamping surface 101 that is inclined so as to approach the movable sheave 66 toward the secondary shaft 52 side.

  The movable sheave 66 includes an inner cylindrical portion 102 that is externally fitted to the secondary shaft 52 so as to be movable in the axial direction thereof, and a hook-shaped portion that projects in a radial shape from an end portion of the inner cylindrical portion 102 on the fixed sheave 65 side. An inner cylindrical portion 102 and an outer cylindrical portion 104 radially opposed to the fixed sheave 65 are integrally provided.

  The end surface on the fixed sheave 65 side of the inner cylindrical portion 102 and the side surface on the fixed sheave 65 side of the bowl-shaped portion 103 are formed flush with each other, and a sandwiching surface 105 inclined so as to approach the fixed sheave 65 toward the secondary shaft 52 side is formed. There is no. A belt 55 is sandwiched between the clamping surface 105 and the clamping surface 101 of the fixed sheave 65.

  In the inner cylindrical portion 102, an oil supply groove 106 is formed over the entire circumference on the inner peripheral surface that rubs against the secondary shaft 52. The oil supply groove 106 is always in communication with the supply oil passage 107 formed inside the secondary shaft 52 regardless of the position of the movable sheave 66 as long as it is within the movable range of the movable sheave 66 (inner cylindrical portion 102). Yes. Further, the inner cylindrical portion 102 is formed with an oil introduction passage 108 whose one end is connected to the oil supply groove 106 and the other end is opened at the outer peripheral surface of the inner cylindrical portion 102. The piston chamber 68 between the movable sheave 66 and the cylinder 67 is supplied with hydraulic pressure from the supply oil passage 107 via the oil supply groove 106 and the oil introduction passage 108.

  The cylinder 67 has a first annular portion 109 projecting in a radial shape from the secondary shaft 52 and an annular shape, and an inner peripheral end thereof is connected to an outer peripheral end portion of the first annular portion 109 on the movable sheave 66 side. And an extending portion 111 extending from the outer peripheral end of the second annular portion 110 to the movable sheave 66 side.

  The inner diameter of the second annular portion 110 is larger than the outer diameter of the inner cylindrical portion 102 of the movable sheave 66, and the inner cylindrical portion 102 can enter inside the second annular portion 110.

  The outer peripheral end of the extending portion 111 is curved or bent radially outward, and a tip end surface 112 thereof is opposed to the outer cylindrical portion 104 of the movable sheave 66 from the inner side in the radial direction. A seal groove 113 is formed on the distal end surface 112 over the entire circumference. An oil seal 114 is fitted in the seal groove 113. The oil seal 114 is in liquid-tight contact with the outer cylindrical portion 104 of the movable sheave 66.

  Further, a spring 115 is interposed between the flange portion 103 of the movable sheave 66 and the second annular portion 110 of the cylinder 67. Due to the elastic force of the spring 115, the movable sheave 66 and the cylinder 67 are urged in a direction away from each other.

  An annular stopper 116 surrounding the periphery of the secondary shaft 52 is disposed on the surface of the first annular portion 109 of the cylinder 67 on the movable sheave 66 side. The stopper 116 is formed separately from the cylinder 67 using a material having a relatively small friction coefficient. The stopper 116 may be formed using a material having a relatively large coefficient of friction, and the surface thereof may be coated to reduce the coefficient of friction.

  When the belt transmission ratio (the transmission ratio of the continuously variable transmission mechanism 43) is maximum, as shown in FIG. 4A, the inner cylindrical portion 102 of the movable sheave 66 comes out of the second annular portion 110 of the cylinder 67 and It faces 67 extending portions 111 with a gap.

  When the winding diameter of the belt 55 with respect to the primary pulley 53 (see FIG. 1) is increased, the movable sheave 66 moves to the cylinder 67 side. As the movement of the movable sheave 66 proceeds, the inner cylindrical portion 102 enters the inside of the second annular portion 110 of the cylinder 67. When the movable sheave 66 is further moved to the cylinder 67 side, the end surface of the inner cylindrical portion 102 on the cylinder 67 side abuts on the stopper 116 as shown in FIG. 4B. Thereby, the further movement of the movable sheave 66 is prevented, and the movable sheave 66 is fixed in a state of being in contact with the stopper 116. Therefore, the winding diameter of the belt 55 with respect to the secondary pulley 54 does not become smaller than that, and at this time, the belt transmission ratio becomes minimum.

  The stopper 116 has its shape (in the movable sheave 66 so that the minimum belt transmission ratio coincides with a predetermined value which is larger than the constant transmission ratio of the split transmission mechanism 45, which is the constant transmission ratio of the split transmission mechanism 45, and less than 1. The thickness of the portion with which the cylindrical portion 102 abuts is designed. The predetermined value may be, for example, a value obtained by adding 0.07 to 0.12 to the split gear ratio if it is larger than the split gear ratio and less than 1. It may be a value obtained by multiplying by -1.3.

<Function effect>
FIG. 5 is a graph showing the relationship between the unit gear ratio of the power split continuously variable transmission 4 and the unit efficiency.

  In the split mode, part of the power input to the input shaft 41 is transmitted to the output shaft via the split transmission mechanism 45. Therefore, in the split mode, as compared with the belt mode at the same belt transmission ratio, the power transmitted to the continuously variable transmission mechanism 43 having lower transmission efficiency than the split transmission mechanism 45 is lower, as shown in FIG. The transmission efficiency (unit efficiency) of the power split type continuously variable transmission 4 is good.

  Further, in the continuously variable transmission mechanism 43, the transmission efficiency in a state where the difference between the winding diameter of the belt 55 with respect to the primary pulley 53 and the winding diameter of the belt 55 with respect to the secondary pulley 54 is small, that is, in a state where the belt speed ratio is around 1. The transmission efficiency decreases as the belt speed ratio deviates from 1. Therefore, as shown in FIG. 5, the power split type continuously variable transmission 4 has the best unit efficiency with the belt transmission ratio being close to 1 in each of the belt mode and split mode power transmission modes. The unit efficiency deteriorates as the gear ratio is away from 1.

  When the movable sheave 66 of the secondary pulley 54 moves away from the fixed sheave 65, the diameter at which the belt is wound around the secondary pulley 54 decreases, and the belt transmission ratio decreases. As the movement of the movable sheave 66 progresses, the movable sheave 66 abuts against the stopper 116 and the further movement of the movable sheave 66 is blocked. At this time, the belt transmission ratio becomes minimum, and the minimum belt transmission ratio coincides with a predetermined value which is larger than the split transmission ratio of the split transmission mechanism 45 and less than one.

  As a result, it is possible to prohibit the belt transmission ratio from becoming smaller than a predetermined value, so that it is possible to suppress the unit transmission ratio from becoming a region of poor unit efficiency near the split transmission ratio. That is, the use of unit efficiency valleys can be avoided.

  The switching between the belt mode and the split mode is achieved by switching between the belt mode clutch C1 and the split mode brake B2 in a state in which the belt gear ratio matches the predetermined value.

  The secondary pulley 54 further includes a cylinder 67 fixedly provided in the moving direction of the movable sheave 66 on the side opposite to the fixed sheave 65 side with respect to the movable sheave 66, and the stopper 116 is formed separately from the cylinder 67. Has been.

  Therefore, by changing the position or shape of the stopper 116, the position of the movable sheave 66 when the movable sheave 66 contacts the stopper 116 can be changed, and the predetermined value (the minimum value of the belt speed ratio) can be changed. it can. Therefore, even if the split transmission ratio of the split transmission mechanism 45 is changed, the position or the shape of the stopper 116 is changed without changing the shape of the cylinder 67, which is larger than the split transmission ratio and less than 1 A predetermined value can be set. Therefore, the power split type continuously variable transmission 4 can have versatility that can be mounted on various vehicle types.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the above-described embodiment, the configuration in which the stopper 116 is formed separately from the cylinder 67 is taken up. However, the stopper 116 may be formed integrally with the cylinder 67. In other words, when the cylinder 67 is formed in a shape that exhibits the function of the stopper 116 and the movable sheave 66 contacts the cylinder 67, the belt speed ratio is greater than the split speed ratio and less than one. The configuration may be consistent with

  Further, in the above-described embodiment, the stopper 116 is provided on the secondary pulley 54, and when the movable sheave 66 comes into contact with the stopper 116 by movement, further movement of the movable sheave 66 is prevented, and the belt speed ratio becomes the split speed change. A configuration that matches a predetermined value that is greater than the ratio and less than 1 was taken up.

  Instead of or in addition to this configuration, a stopper may be provided on primary pulley 53 for the purpose of obtaining the same function and effect. That is, when the primary pulley 53 is provided with a stopper and the movable sheave 62 contacts the stopper by movement, further movement of the movable sheave 62 is prevented, the belt speed ratio is larger than the split speed ratio, and 1 A configuration that coincides with a predetermined value that is less than may be employed.

  For example, the shape of each part (such as the cylinder 67) of the secondary pulley 54 is an example, and may be appropriately changed according to the size of the secondary pulley 54 and the like.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

4 power split type continuously variable transmission 41 input shaft 42 output shaft 43 continuously variable transmission mechanism 44 planetary gear mechanism for output 45 split transmission mechanism 53 primary pulley 54 secondary pulley 55 belt 65 fixed sheave 66 movable sheave 116 stopper

Claims (1)

A belt-type continuously variable transmission mechanism that changes the power input to the input shaft steplessly by changing the belt transmission ratio; a split transmission mechanism that changes the power input to the input shaft at a constant split transmission ratio; An output gear mechanism that outputs power to the output shaft, and a belt mode in which power input to the input shaft is transmitted to the output gear mechanism via the continuously variable transmission mechanism; and an input to the input shaft A power split type continuously variable transmission, in which a selected power is selectively switched to a split mode in which the power is transmitted to the output gear mechanism via the continuously variable transmission mechanism and the split transmission mechanism,
The continuously variable transmission mechanism has a configuration in which a belt is wound around a primary pulley and a secondary pulley,
At least one of the primary pulley and the secondary pulley is
With fixed sheave,
A movable sheave disposed opposite to the fixed sheave with the belt interposed therebetween and movably provided in a direction opposite to the fixed sheave;
The movable sheave moving toward the side away from the fixed sheave abuts, and at a position where a belt gear ratio corresponding to a predetermined value larger than the split gear ratio and smaller than 1 is obtained. Power split type continuously variable transmission comprising a blocking stopper.

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