JP7090979B2 - Control device for continuously variable transmission - Google Patents

Description

The present invention relates to a control device for a continuously variable transmission.

A belt-type continuously variable transmission (CVT) is widely known as a transmission mounted on a vehicle.

The belt-type continuously variable transmission has a configuration in which an endless belt is wound around a primary pulley on the input side and a secondary pulley on the output side. Each pulley of the primary pulley and the secondary pulley is provided with a fixed sheave and a movable sheave facing the fixed sheave with a belt sandwiched between them. The distance between the fixed sheave and the movable sheave is changed by controlling the hydraulic pressure acting on the movable sheave of each pulley. Along with this, the winding diameter of the belt with respect to the primary pulley changes, the distance between the fixed sheave and the movable sheave of the secondary pulley changes, and the winding diameter of the belt with respect to the secondary pulley changes. As a result, the gear ratio (pulley ratio) changes steplessly and continuously.

Japanese Unexamined Patent Publication No. 2004-176890

In some continuously variable transmissions, if the gear ratio at the time of starting the vehicle is set to the maximum gear ratio (maximum low gear ratio), the total reduction ratio becomes too large and the driving force is excessive, so the gear ratio is maximized at the time of starting. Some are set to a gear ratio that is slightly smaller than the gear ratio (set on the Hi side). In a vehicle equipped with this continuously variable transmission, the acceleration at the time of starting becomes excessive and it is difficult to drive, the creep force is excessive and the brake cannot be stopped unless the brake is pressed strongly, and the grown sound is generated due to insufficient braking force. You can avoid the problem.

However, if the vehicle is loaded with more luggage than expected, if the road surface on which the vehicle is traveling has an unexpected slope or step, or if the drive source torque drops due to an abnormality in the drive source such as the engine, etc. In addition, the vehicle may not be able to start.

An object of the present invention is a continuously variable transmission control device capable of suppressing an excessive driving force for starting a vehicle during normal times and suppressing the inability to start the vehicle other than during normal times. Is to provide.

In order to achieve the above object, the control device of the stepless transmission according to the present invention moves in the rotation axis direction with respect to the fixed sheave and the fixed sheave on the power transmission path between the input shaft and the output shaft. It is a control device for a stepless transmission having a structure in which a belt is sandwiched between a movable sheave provided as possible, and is input to the input shaft from a drive source of a vehicle on which the stepless transmission is mounted. The torque is not transmitted to the output shaft, and in this state, the distance between the fixed sheave and the movable sheave is changed to set the gear ratio of the stepless transmission to the maximum gear ratio side (Low side). change.

According to this configuration, when the vehicle cannot start, the torque of the drive source of the vehicle is not transmitted to the output shaft, and the distance between the fixed sheave and the movable sheave is changed in that state. , The gear ratio of the continuously variable transmission is changed to the maximum gear ratio side (Low side). As a result, the driving force for starting the vehicle is increased, so that the vehicle can be started satisfactorily. Further, before the gear ratio is changed to the maximum gear ratio side, the gear ratio is set to a gear ratio smaller than the maximum gear ratio, so that it is possible to prevent the driving force for starting the vehicle from becoming excessive. ..

According to the present invention, it is possible to suppress that the driving force for starting the vehicle becomes excessive in the normal time, and to prevent the vehicle from being unable to start in other than the normal time.

It is a skeleton diagram which shows the structure of the drive system of a vehicle. It is a figure which shows the state of each engaging element provided in a transmission. It is a collinear diagram which shows the relationship of the rotation speed (rotational speed) of a sun gear, a carrier and a ring gear of a planetary gear mechanism provided in a transmission. It is a figure which shows the relationship between the gear ratio (belt gear ratio) of the continuously variable transmission mechanism provided in a transmission, and the gear ratio (unit gear ratio) of the whole power split type continuously variable transmission. It is a figure which shows the structure of the control system which concerns on one Embodiment of this invention. It is a flowchart which shows an example of a start control. It is a flowchart which shows the other example of a start control. It is a flowchart which shows still another example of a start control. It is a skeleton diagram which shows the structure of the CVT which provided the forward / backward switching mechanism in front of a stepless speed change mechanism.

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

<Vehicle drive system>
FIG. 1 is a skeleton diagram showing the configuration of the drive system of the vehicle 1.

The vehicle 1 is an automobile whose drive source is the engine 2.

The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) that injects fuel into the intake air, an ignition plug that causes an electric discharge in the combustion chamber, and the like. Has been done. Further, the engine 2 is provided with a starter for starting the engine 2. The power of the engine 2 is transmitted to the differential gear 5 via the torque converter 3 and the transmission 4, and is transmitted from the differential gear 5 to the left and right drive wheels 7L and 7R via the left and right drive shafts 6L and 6R, respectively. ..

The engine 2 includes an E / G output shaft 11. The E / G output shaft 11 is rotated by the power generated by the engine 2.

The torque converter 3 includes a front cover 21, a pump impeller 22, a turbine runner 23, and a lockup mechanism 24. The E / G output shaft 11 is connected to the front cover 21, and the front cover 21 rotates integrally with the E / G output shaft 11. The pump impeller 22 is arranged on the side opposite to the engine 2 side with respect to the front cover 21. The pump impeller 22 is provided so as to be rotatable integrally with the front cover 21. The turbine runner 23 is arranged between the front cover 21 and the pump impeller 22 and is rotatably provided about a rotation axis common to the front cover 21.

The lockup mechanism 24 includes a lockup piston 25. The lockup piston 25 is provided between the front cover 21 and the turbine runner 23. The lockup mechanism 24 is provided by the differential pressure between the hydraulic pressure of the release oil chamber 26 between the lockup piston 25 and the front cover 21 and the hydraulic pressure of the engagement oil chamber 27 between the lockup piston 25 and the pump impeller 22. Lock-up is turned on (engaged) / off (released). That is, when the hydraulic pressure of the release oil chamber 26 is higher than the hydraulic pressure of the engaging oil chamber 27, the lockup piston 25 is separated from the front cover 21 due to the differential pressure, and the lockup is turned off. When the hydraulic pressure of the engaging oil chamber 27 is higher than the hydraulic pressure of the release oil chamber 26, the lockup piston 25 is pressed against the front cover 21 by the differential pressure to lock up on.

In the lock-up-off state, when the E / G output shaft 11 is rotated, the pump impeller 22 rotates. When the pump impeller 22 rotates, an oil flow from the pump impeller 22 to the turbine runner 23 is generated. This flow of oil is received by the turbine runner 23, and the turbine runner 23 rotates. At this time, the amplification action of the torque converter 3 occurs, and the turbine runner 23 generates a power larger than the power (torque) of the E / G output shaft 11.

In the lockup-on state, when the E / G output shaft 11 is rotated, the E / G output shaft 11, the pump impeller 22 and the turbine runner 23 rotate together.

The transmission 4 includes an input shaft 31 and an output shaft 32, and is configured to be able to branch the power input to the input shaft 31 into two paths and transmit the power to the output shaft 32, that is, a so-called power split type (torque). Split type) transmission. In order to form two power transmission paths, the transmission 4 includes a continuously variable transmission mechanism 33, a front reduction gear mechanism 34, a planetary gear mechanism 35, and a split transmission mechanism 36.

The input shaft 31 is connected to the turbine runner 23 of the torque converter 3 and is provided so as to be integrally rotatable around the same rotation axis as the turbine runner 23.

The output shaft 32 is provided in parallel with the input shaft 31. An output gear 37 is supported on the output shaft 32 so as to be relatively non-rotatable. The output gear 37 meshes with the differential gear 5 (the ring gear of the differential gear 5).

The continuously variable transmission mechanism 33 has the same configuration as a known belt-type continuously variable transmission (CVT). Specifically, the continuously variable transmission mechanism 33 includes a primary shaft 41, a secondary shaft 42 provided in parallel with the primary shaft 41, a primary pulley 43 supported by the primary shaft 41 so as not to rotate relative to the primary shaft 41, and a secondary shaft 42. It is provided with a secondary pulley 44 that is supported so as not to rotate relative to each other, and a belt 45 that is wound around the primary pulley 43 and the secondary pulley 44.

The primary pulley 43 is arranged to face the fixed sheave 51 fixed to the primary shaft 41 with the belt 45 sandwiched between the fixed sheave 51, and is supported by the primary shaft 41 so as to be movable in the axial direction and non-relatively rotatable. It is equipped with 52. A cylinder 53 fixed to the primary shaft 41 is provided on the opposite side of the movable sheave 52 from the fixed sheave 51, and a hydraulic chamber 54 is formed between the movable sheave 52 and the cylinder 53.

The secondary pulley 44 is arranged so as to face the fixed sheave 55 fixed to the secondary shaft 42 with the belt 45 sandwiched between the fixed sheave 55, and is supported by the secondary shaft 42 so as to be movable in the axial direction and non-relatively rotatable. It is equipped with 56. A cylinder 57 fixed to the secondary shaft 42 is provided on the opposite side of the movable sheave 56 from the fixed sheave 55, and a hydraulic chamber 58 is formed between the movable sheave 56 and the cylinder 57. In the direction of the rotation axis, the positional relationship between the fixed sheave 55 and the movable sheave 56 is reversed from the positional relationship between the fixed sheave 51 and the movable sheave 52 of the primary pulley 43.

In the continuously variable transmission mechanism 33, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 and the hydraulic chamber 58 of the secondary pulley 44 is controlled, respectively, and the groove widths of the primary pulley 43 and the secondary pulley 44 are changed. , The gear ratio (pulley ratio) between the primary pulley 43 and the secondary pulley 44 is continuously and steplessly changed.

Specifically, when the gear ratio is reduced, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 is increased. As a result, the movable sheave 52 of the primary pulley 43 moves toward the fixed sheave 51, and the distance (groove width) between the fixed sheave 51 and the movable sheave 52 becomes smaller. Along with this, the winding diameter of the belt 45 with respect to the primary pulley 43 becomes large, and the distance (groove width) between the fixed sheave 55 and the movable sheave 56 of the secondary pulley 44 becomes large. As a result, the gear ratio between the primary pulley 43 and the secondary pulley 44 becomes small.

When the gear ratio is increased, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 is lowered. As a result, the thrust ratio, which is the ratio of the thrust (primary thrust) of the primary pulley 43 to the thrust of the secondary pulley 44 (secondary thrust), becomes smaller, and the distance between the fixed sheave 55 and the movable sheave 56 of the secondary pulley 44 becomes smaller. , The distance between the fixed sheave 51 and the movable sheave 52 becomes large. As a result, the gear ratio between the primary pulley 43 and the secondary pulley 44 becomes large.

On the other hand, the thrust of the primary pulley 43 and the secondary pulley 44 needs to have a magnitude such that slip (belt slip) does not occur between the primary pulley 43 and the secondary pulley 44 and the belt 45. Therefore, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 and the hydraulic chamber 58 of the secondary pulley 44 is controlled so that the necessary and sufficient pinching pressure that does not cause belt slippage can be obtained.

The front reduction gear mechanism 34 is configured to reverse and decelerate the power input to the input shaft 31 and transmit it to the primary shaft 41. Specifically, the front reduction gear mechanism 34 has a larger diameter and a larger number of teeth than the input shaft gear 61 supported by the input shaft 31 so as not to rotate relative to the input shaft gear 61, and is spline-fitted to the primary shaft 41. Includes a primary shaft gear 62 that is supported by the relative non-rotatable gear and meshes with the input shaft gear 61.

The planetary gear mechanism 35 includes a sun gear 71, a carrier 72, and a ring gear 73. The sun gear 71 is supported on the secondary shaft 42 so as not to rotate relative to each other by spline fitting. The carrier 72 is externally fitted to the output shaft 32 so as to be relatively rotatable. The carrier 72 rotatably supports a plurality of pinion gears 74. A 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 radial direction of rotation of the secondary shaft 42. Further, an output shaft 32 is connected to the ring gear 73, and the ring gear 73 is provided so as to be integrally rotatable around the same rotation axis as the output shaft 32.

The split gear mechanism 36 is a parallel shaft gear mechanism including a split drive gear 81 and a split driven gear 82 that meshes with the split drive gear 81.

The split drive gear 81 is externally fitted to the input shaft 31 so as to be relatively rotatable.

The split driven gear 82 is provided so as to be integrally rotatable around the same rotation axis as the carrier 72 of the planetary gear mechanism 35. The split driven gear 82 is formed to have a smaller diameter than the split drive gear 81, and has a smaller number of teeth than the split drive gear 81.

Further, the transmission 4 includes clutches C1 and C2 and a brake B1.

The clutch C1 is hydraulically switched between an engaged state in which the input shaft 31 and the split drive gear 81 are directly connected (coupled so as to be integrally rotatable) and an released state in which the direct connection is released.

The clutch C2 is hydraulically switched between an engaged state in which the sun gear 71 of the planetary gear mechanism 35 and the ring gear 73 are directly connected (coupled so as to be integrally rotatable) and an released state in which the direct connection is released.

The brake B1 is hydraulically switched between an engaged state in which the carrier 72 of the planetary gear mechanism 35 is braked and an released state in which the carrier 72 is allowed to rotate.

<Power transmission mode>
FIG. 2 is a diagram showing the states of the clutches C1 and C2 and the brake B1 when the vehicle 1 is moving forward and backward. FIG. 3 is a collinear diagram showing the relationship between the rotation speeds (rotational speeds) of the sun gear 71, the carrier 72, and the ring gear 73 of the planetary gear mechanism 35. FIG. 4 shows the relationship between the gear ratio by the continuously variable transmission mechanism 33 and the reduction ratio (unit gear ratio) of the entire transmission 4, that is, the reduction ratio which is the rotation speed ratio between the input shaft 31 and the output shaft 32. It is a figure.

In FIG. 2, “◯” indicates that the clutches C1 and C2 and the brake B1 are in the engaged state. “X” indicates that the clutches C1 and C2 and the brake B1 are in the released state.

A shift lever (select lever) is arranged in the vehicle interior of the vehicle 1 at a position where the driver can operate the vehicle. In the movable range of the shift lever, for example, a P (parking) position, an R (reverse) position, an N (neutral) position, and a D (drive) position are provided in this order in a row.

When the shift lever is in the P position, all of the clutches C1 and C2 and the brake B1 are released, and the parking lock gear (not shown) is fixed, which is one of the shift ranges of the transmission 4. The P range is configured. Further, when the shift lever is in the N position, all of the clutches C1 and C2 and the brake B1 are released, and the parking lock gear is not fixed, so that the N range, which is one of the shift ranges of the transmission 4, is set. It is composed. When both the clutch C1 and the brake B1 are released, the power of the engine 2 is transmitted to the secondary shaft 42 and the secondary shaft 42 rotates, but the sun gear 71 and the pinion gear 74 of the planetary gear mechanism 35 slip and the engine The power of 2 is not transmitted to the drive wheels 7L and 7R.

When the shift lever is in the D position, a forward range, which is one of the shift ranges of the transmission 4, is configured. Power transmission modes in this forward range include belt mode and split mode. The belt mode and the split mode are switched by switching between the state in which the clutch C1 is engaged and the state in which the clutch C2 is engaged (replacement of the clutches C1 and C2).

In the belt mode, as shown in FIG. 2, the clutch C1 and the brake B1 are released and the clutch C2 is engaged. As a result, the split drive gear 81 is separated from the input shaft 31, the carrier 72 of the planetary gear mechanism 35 becomes free (free rotation state), and the sun gear 71 of the planetary gear mechanism 35 and the ring gear 73 are directly connected.

The power input to the input shaft 31 is reversed and decelerated by the front reduction gear mechanism 34 and transmitted to the primary shaft 41 of the continuously variable transmission mechanism 33 to rotate the primary shaft 41 and the primary pulley 43. The rotation of the primary pulley 43 is transmitted to the secondary pulley 44 via the belt 45 to rotate the secondary pulley 44 and the secondary shaft 42. Since the sun gear 71 of the planetary gear mechanism 35 and the ring gear 73 are directly connected, the sun gear 71, the ring gear 73, and the output shaft 32 rotate integrally with the secondary shaft 42. Therefore, in the belt mode, as shown in FIGS. 3 and 4, the reduction ratio is the gear ratio of the continuously variable transmission mechanism 33 (the pulley ratio of the primary pulley 43 and the secondary pulley 44) and the front reduction ratio (of the input shaft 31). It matches the value multiplied by the number of rotations / the number of rotations of the primary shaft 41).

In the split mode, as shown in FIG. 2, the clutch C1 is engaged and the clutch C2 and the brake B1 are released. As a result, the input shaft 31 and the split drive gear 81 are coupled, and the rotation of the input shaft 31 can be transmitted to the carrier 72 of the planetary gear mechanism 35 via the split drive gear 81 and the split driven gear 82, and the planetary gear mechanism The sun gear 71 of 35 and the ring gear 73 are separated.

The power input to the input shaft 31 is accelerated and transmitted from the split drive gear 81 to the carrier 72 of the planetary gear mechanism 35 via the split driven gear 82. The power transmitted to the carrier 72 is divided and transmitted from the carrier 72 to the sun gear 71 and the ring gear 73. The power of the sun gear 71 is transmitted to the primary shaft gear 62 via the secondary shaft 42, the secondary pulley 44, the belt 45, the primary pulley 43 and the primary shaft 41, and is transmitted from the primary shaft gear 62 to the input shaft gear 61. Therefore, in the belt mode, the input shaft gear 61 becomes the drive gear and the primary shaft gear 62 becomes the driven gear, whereas in the split mode, the primary shaft gear 62 becomes the drive gear and the input shaft gear 61 becomes the driven gear. ..

Since the gear ratio between the split drive gear 81 and the split driven gear 82 is constant and constant (fixed), in the split mode, if the power input to the input shaft 31 is constant, the carrier 72 of the planetary gear mechanism 35 rotates. Is kept at a constant speed. Therefore, when the gear ratio is increased, the rotation speed of the sun gear 71 of the planetary gear mechanism 35 decreases, so that the rotation speed of the ring gear 73 (output shaft 32) of the planetary gear mechanism 35 decreases as shown by the broken line in FIG. Go up. As a result, in the split mode, as shown in FIG. 4, the larger the gear ratio of the stepless speed change mechanism 33, the smaller the reduction ratio of the transmission 4, and the sensitivity of the reduction ratio to the gear ratio (the amount of change in the gear ratio). The ratio of the amount of change in the reduction ratio to the belt mode) is lower than that in the belt mode.

The rotation of the output shaft 32 in the belt mode and the split mode is transmitted to the differential gear 5 via the output gear 37. As a result, the drive shafts 6L and 6R and the drive wheels 7L and 7R of the vehicle 1 rotate in the forward direction.

When the shift lever is in the R position, the reverse range, which is one of the shift ranges of the transmission 4, is configured. In the reverse range, as shown in FIG. 2, the clutches C1 and C2 are released and the brake B1 is engaged. As a result, the split drive gear 81 is disconnected from the input shaft 31, the sun gear 71 of the planetary gear mechanism 35 and the ring gear 73 are disconnected, and the carrier 72 of the planetary gear mechanism 35 is braked.

The power input to the input shaft 31 is reversed and decelerated by the front reduction gear mechanism 34 and transmitted to the primary shaft 41 of the stepless speed change mechanism 33, from the primary shaft 41 to the primary pulley 43, the belt 45 and the secondary pulley 44. It is transmitted to the secondary shaft 42 via the secondary shaft 42, and the sun gear 71 of the planetary gear mechanism 35 is rotated integrally with the secondary shaft 42. Since the carrier 72 of the planetary gear mechanism 35 is braked, when the sun gear 71 rotates, the ring gear 73 of the planetary gear mechanism 35 rotates in the opposite direction to the sun gear 71. The rotation direction of the ring gear 73 is opposite to the rotation direction of the ring gear 73 during forward movement (belt mode and split mode). Then, the output shaft 32 rotates integrally with the ring gear 73. The rotation of the output shaft 32 is transmitted to the differential gear 5 via the output gear 37. As a result, the drive shafts 6L and 6R and the drive wheels 7L and 7R of the vehicle 1 rotate in the reverse direction.

<Vehicle control system>
FIG. 5 is a block diagram showing the configuration of the control system of the vehicle 1.

The vehicle 1 is provided with an ECU (Electronic Control Unit) having a configuration including a microcomputer (microcontroller unit). The microcomputer has, for example, a built-in non-volatile memory such as a CPU and a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory). Although FIG. 5 shows only one ECU 91 for controlling the transmission 4, the vehicle 1 is equipped with a plurality of ECUs having the same configuration as the ECU 91 in order to control each part. .. A plurality of ECUs including the ECU 91 are connected so as to be capable of bidirectional communication by a CAN (Controller Area Network) communication protocol.

Various sensors required for control are connected to the ECU 91. As an example, the ECU 91 outputs a turbine rotation sensor 92 that outputs a pulse signal synchronized with the rotation of the turbine runner 23 of the torque converter 3 as a detection signal, and a pulse signal synchronized with the rotation of the primary shaft 41 as a detection signal. A primary rotation sensor 93, a secondary rotation sensor 94 that outputs a pulse signal synchronized with the rotation of the secondary shaft 42 as a detection signal, and an output rotation sensor 95 that outputs a pulse signal synchronized with the rotation of the output shaft 32 as a detection signal. And the shift position sensor 96 that outputs the detection signal corresponding to each position of the P, R, N, D position of the shift lever, and the detection according to the operation amount of the accelerator pedal (not shown) operated by the driver. It is connected to an accelerator sensor 97 that outputs a signal.

In the ECU 91, the turbine rotation speed, which is the rotation speed of the turbine runner 23, and the primary rotation speed (from the detection signals of the turbine rotation sensor 92, the primary rotation sensor 93, the secondary rotation sensor 94, the output rotation sensor 95, and the shift position sensor 96, The primary rotation speed, which is the rotation speed of the primary pulley 43), the secondary rotation speed, which is the rotation speed of the secondary shaft 42 (secondary pulley 44), the output rotation speed, which is the rotation speed of the output shaft 32, and the position of the shift lever are To be acquired. Further, in the ECU 91, from the detection signal of the accelerator sensor 97, the ratio of the operation amount to the maximum operation amount of the accelerator pedal, that is, 0% when the accelerator pedal is not depressed, and 100 when the accelerator pedal is depressed to the maximum. The accelerator opening, which is a percentage of%, is obtained. Then, the ECU 91 supplies hydraulic pressure to each part of the unit including the transmission 4 for shifting control of the transmission 4 based on information acquired from various sensors, information input from other ECUs, and the like. Various valves included in the hydraulic circuit for this are controlled.

<Start control 1>
FIG. 6 is a flowchart showing an example of start control.

When the shift lever in the vehicle interior is displaced from the P position or the N position to the D position or the R position, the ECU 91 executes the start control.

In the start control, the gear ratio of the continuously variable transmission mechanism 33 is set to a start gear ratio smaller than the maximum gear ratio (step S11). As a result, the reduction ratio of the transmission 4 becomes a reduction ratio smaller than the maximum reduction ratio.

When the shift lever in the vehicle interior is displaced from the P position or the N position to the D position, the clutch C2 is engaged and the vehicle 1 normally starts to move forward. Further, when the shift lever is displaced from the P position or the N position to the R position, the brake B1 is engaged and the vehicle 1 normally starts to move backward.

When the vehicle 1 starts moving forward or backward, that is, when the vehicle 1 starts (NO in step S12), the start control is terminated.

When the vehicle 1 does not start (YES in step S12), it is determined whether or not the shift lever is displaced from the D position or the R position to the N position (step S13).

Then, when the shift lever is displaced from the D position or the R position to the N position (YES in step S13), the gear ratio of the continuously variable transmission mechanism 33 is maximized accordingly. The gear ratio side is changed by a predetermined amount (step S14).

After that, when the shift lever is displaced from the N position (P position) to the D position or the R position (YES in step S15), the start control is terminated.

<Action effect>
When the vehicle 1 cannot start, the gear ratio of the continuously variable transmission mechanism 33 is changed to the maximum gear ratio side (Low side) according to the displacement of the shift lever to the N position. When the shift lever is in the N position and all of the clutches C1, C2 and the brake B1 are released, the primary pulley 43 and the secondary pulley 44 are rotated by the power of the engine 2, so that the gear ratio can be changed. It is possible. By changing the gear ratio to the maximum gear ratio side, the driving force for starting the vehicle 1 increases, so that the vehicle 1 can be started satisfactorily. Further, before the gear ratio is changed to the maximum gear ratio side, the gear ratio is set to a starting gear ratio smaller than the maximum gear ratio, so that the driving force for starting the vehicle 1 becomes excessive. Can be suppressed.

<Start control 2>
FIG. 7 is a flowchart showing another example of start control.

In another example of the start control, the gear ratio of the continuously variable transmission mechanism 33 is set to a smaller gear ratio than the maximum gear ratio in the state where the shift lever is in the P position or the N position before the vehicle 1 starts. (Step S21).

Then, when the shift lever in the vehicle interior is displaced from the P position or the N position to the D position, whether or not the road surface on which the vehicle 1 is located is uphill in the starting direction of the vehicle 1 before the clutch C2 is engaged. Is determined (step S22). The slope of the road surface can be obtained from the detection signal of the G sensor. As the G sensor, for example, one that outputs a signal corresponding to the displacement of the weight as a detection signal corresponding to the acceleration of the vehicle 1 is adopted. Therefore, since the detection signal corresponding to the slope of the road surface is output from the G sensor, the slope (inclination angle) of the road surface where the vehicle 1 is located can be obtained from the detection signal of the G sensor.

When the road surface is an uphill slope in the starting direction of the vehicle 1 (YES in step S22), the gear ratio of the continuously variable transmission mechanism 33 is changed by a predetermined amount to the maximum gear ratio side (step S23), and the starting control is performed. It will be terminated. When the road surface is not an uphill slope in the starting direction of the vehicle 1 (NO in step S22), the starting control is completed while the gear ratio of the continuously variable transmission mechanism 33 is set to the starting gear ratio (skipping in step S23). Will be done.

<Action effect>
According to this start control, normally, the gear ratio of the continuously variable transmission mechanism 33 at the time of starting the vehicle 1 is set to a smaller gear ratio than the maximum gear ratio. As a result, it is possible to prevent the driving force for starting the vehicle 1 from becoming excessive. Further, when the slope of the road surface on which the vehicle 1 is located is an upward slope in the starting direction, the gear ratio of the continuously variable transmission mechanism 33 is changed to the maximum gear ratio side before the vehicle 1 starts. Therefore, the vehicle 1 can be started satisfactorily.

<Start control 3>
FIG. 8 is a flowchart showing still another example of start control.

In the start control shown in FIG. 8, when the shift lever in the vehicle interior is displaced from the P position or the N position to the D position or the R position, the gear ratio of the continuously variable transmission mechanism 33 is smaller than the maximum gear ratio. Is set to (step S31).

After that, when the clutch C2 is engaged, the vehicle 1 usually starts to move forward. Further, when the shift lever is displaced from the P position or the N position to the R position, the brake B1 is engaged and the vehicle 1 normally starts to move backward.

When the vehicle 1 starts moving forward or backward, that is, when the vehicle 1 starts (NO in step S32), the start control is terminated.

When the vehicle 1 does not start (YES in step S32), it is determined whether or not the accelerator pedal depression operation is released and the accelerator opening is returned to the predetermined opening or less (for example, 0) (step S33). ..

Then, the accelerator opening is returned to the predetermined opening or less (YES in step S33), and the engagement pressure (clutch pressure) of the clutch C2 is controlled so that the clutch C2 slips accordingly. , The primary pulley 43 and the secondary pulley 44 are rotated, and the gear ratio is changed to the maximum gear ratio side by a predetermined amount (step S34). After that, the start control is terminated.

<Action effect>
This start control can also exert the same effect as in the case of the start control shown in FIG. Further, by sliding the clutch C2 in a state where the accelerator opening degree is returned to the predetermined opening degree or less, the vehicle 1 can be started satisfactorily while preventing the clutch C2 from being damaged.

<Modification example>
In the above-described embodiment, the power split type (torque split type) transmission is taken up as the transmission 4, but the control device according to the present invention is not limited to the power split type transmission 4, and is shown in FIG. It can also be mounted on a vehicle 101 equipped with a CVT 104 having such a configuration.

The vehicle 101 is an automobile whose drive source is the engine 102. The power of the engine 102 is transmitted to the differential gear 105 via the torque converter 103 and the belt-type CVT 104, and is transmitted from the differential gear 105 to the left and right drive wheels 107L and 107R via the left and right drive shafts 106L and 106R, respectively. To.

The torque converter 103 is a torque converter with a lock-up mechanism, and includes a front cover 111, a pump impeller 112, a turbine runner 113, and a lock-up clutch 114. The crankshaft of the engine 102 is connected to the front cover 111, and the front cover 111 rotates integrally with the crankshaft. The pump impeller 112 is arranged on the side opposite to the engine side with respect to the front cover 111. The pump impeller 112 is provided so as to be rotatable integrally with the front cover 111. The turbine runner 113 is arranged between the front cover 111 and the pump impeller 112, and is rotatably provided about a rotation axis common to the front cover 111. The lockup clutch 114 is arranged between the front cover 111 and the turbine runner 113.

The lockup clutch 114 is a differential pressure between the hydraulic pressure of the release side oil chamber 115 between the lockup clutch 114 and the front cover 111 and the hydraulic pressure of the engagement side oil chamber 116 between the lockup clutch 114 and the pump impeller 112. Engages / disengages with. That is, when the hydraulic pressure of the release side oil chamber 115 is higher than the hydraulic pressure of the engagement side oil chamber 116, the lockup clutch 114 is separated from the front cover 111 due to the differential pressure, and the lockup clutch 114 is released. It becomes an up-off state (released state). When the hydraulic pressure of the engaging side oil chamber 116 is higher than the hydraulic pressure of the releasing side oil chamber 115, the differential pressure causes the lockup clutch 114 to be pressed against the front cover 111, and the lockup clutch 114 is engaged with the lock. It becomes an up-on state (fastened state).

When the E / G output shaft is rotated in the lock-up / off state, the pump impeller 112 rotates. When the pump impeller 112 rotates, an oil flow from the pump impeller 112 to the turbine runner 113 is generated. This flow of oil is received by the turbine runner 113, and the turbine runner 113 rotates. At this time, the amplification action of the torque converter 103 occurs, and the turbine runner 113 generates a power larger than the power (torque) of the E / G output shaft.

In the lockup-on state, when the E / G output shaft is rotated, the E / G output shaft, the pump impeller 112, and the turbine runner 113 rotate together.

An oil pump 108 is provided between the torque converter 103 and the CVT 104. The oil pump 108 is a mechanical oil pump, and the pump shaft is provided so as to rotate integrally with the pump impeller 112 of the torque converter 103. As a result, when the pump impeller 112 is rotated by the power of the engine 102, the pump shaft of the oil pump 108 is rotated, and hydraulic pressure is generated from the oil pump 108.

The CVT 104 transmits the power input from the torque converter 103 to the differential gear 105. The CVT 104 includes an input shaft 121, an output shaft 122, a belt transmission mechanism 123, and a forward / backward switching mechanism 124.

The input shaft 121 is connected to the turbine runner 113 of the torque converter 103, and is provided so as to be integrally rotatable around the same rotation axis as the turbine runner 113.

The output shaft 122 is arranged in parallel with the input shaft 121. An output gear 125 is supported on the output shaft 122 so as to be relatively non-rotatable.

The belt transmission mechanism 123 includes a primary shaft 131 and a secondary shaft 132. The primary axis 131 and the secondary axis 132 are arranged on the same axis as the input axis 121 and the output axis 122, respectively.

The belt transmission mechanism 123 has a configuration in which an endless belt 135 is wound around a primary pulley 133 supported by a primary shaft 131 and a secondary pulley 134 supported by a secondary shaft 132.

The primary pulley 133 is a movable sheave that is arranged so as to face the fixed sheave 141 fixed to the primary shaft 131 and the fixed sheave 141 with the belt 135 interposed therebetween, and is supported by the primary shaft 131 so as to be movable in the axial direction and not to rotate relative to each other. It is equipped with 142. A piston 143 fixed to the primary shaft 131 is provided on the opposite side of the movable sheave 142 from the fixed sheave 141, and a piston chamber 144 is formed between the movable sheave 142 and the piston 143.

The secondary pulley 134 is arranged so as to face the fixed sheave 145 fixed to the secondary shaft 132 and the fixed sheave 145 with the belt 135 interposed therebetween, and is supported by the secondary shaft 132 so as to be movable in the axial direction and non-relatively rotatable. It is equipped with a movable sheave 146. A piston 147 fixed to the secondary shaft 132 is provided on the opposite side of the movable sheave 146 from the fixed sheave 145, and a piston chamber 148 is formed between the movable sheave 146 and the piston 147.

The movement of the movable sheave 142 of the primary pulley 133 continuously changes the groove width, which is the distance between the fixed sheave 141 and the movable sheave 142. Due to the movement of the movable sheave 146 of the secondary pulley 134, the groove width which is the distance between the fixed sheave 145 and the movable sheave 146 changes continuously. By continuously changing the groove widths of the primary pulley 133 and the secondary pulley 134, the winding diameter of the belt 135 with respect to the primary pulley 133 and the secondary pulley 134 can be changed, and the gear ratio (pulley ratio) can be steplessly changed. Can be changed continuously with.

Although not shown, a bias spring for applying an initial pinching pressure (initial thrust) to the belt 135 is interposed between the movable sheave 146 and the piston 147. The elastic force of the bias spring urges the movable sheave 146 and the piston 147 in a direction away from each other.

The forward / backward switching mechanism 124 is interposed between the input shaft 121 and the primary shaft 131 of the belt transmission mechanism 123. The forward / backward switching mechanism 124 includes a planetary gear mechanism 151, a clutch C, and a brake B.

The planetary gear mechanism 151 includes a carrier 152, a sun gear 153, and a ring gear 154.

The carrier 152 is externally fitted to the input shaft 121 so as to be relatively rotatable. The carrier 152 rotatably supports a plurality of pinion gears 155. The plurality of pinion gears 155 are arranged on the circumference.

The sun gear 153 is supported by the input shaft 121 so as not to rotate relative to each other, and is arranged in a space surrounded by a plurality of pinion gears 155. The gear teeth of the sun gear 153 mesh with the gear teeth of each pinion gear 155.

The ring gear 154 is provided so that its rotation axis coincides with the axis of the primary shaft 131. The primary shaft 131 of the belt transmission mechanism 123 is connected to the ring gear 154. The gear teeth of the ring gear 154 are formed so as to collectively surround a plurality of pinion gears 155, and mesh with the gear teeth of each pinion gear 155.

The clutch C is hydraulically switched between an engaged state (on) in which the carrier 152 and the sun gear 153 are directly connected (coupled so as to be integrally rotatable) and an released state (off) in which the direct connection is released.

The brake B is provided between the carrier 152 and the transmission case accommodating the torque converter 103 and the CVT 104, and is in an engaged state (on) in which the carrier 152 is hydraulically braked and an released state (on) in which the carrier 152 is allowed to rotate (on). It can be switched to (off).

In the configuration of the CVT 104, the primary pulley 133 and the secondary pulley 134 do not rotate in the neutral state in which both the clutch C and the brake B are released. Therefore, when changing the gear ratio to the maximum gear ratio side when the vehicle 1 cannot start, the hydraulic pressure is removed from the piston chamber 148 of the primary pulley 133 in the neutral state, and the primary pulley 133 and the belt 135 are slid. , The gear ratio may be changed by moving the movable sheave 142.

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

1,101: Vehicle 2,102: Engine (drive source)
4,104: Transmission (continuously variable transmission)
31,121: Input shaft 32,122: Output shaft 45,135: Belt 51,55,141,145: Fixed sheave 52,56,142,146: Movable sheave 91: ECU (control device)

Claims (1)

A primary pulley and a secondary pulley are provided on the power transmission path between the input shaft and the output shaft so that the primary pulley and the secondary pulley can move in the rotation axis direction with respect to the fixed sheave and the fixed sheave, respectively. It is equipped with a movable sheave provided, and is equipped with a continuously variable transmission having a structure in which a belt is sandwiched between the fixed sheave and the movable sheave, and the movable range of the shift lever is a parking position, a reverse position, and a neutral position. A control device used in a vehicle provided with a position and a drive position .
The vehicle can not start , the shift lever is displaced from the drive position or the reverse position to the neutral position, and torque from the drive source of the vehicle is not input to the input shaft but is input to the input shaft. When a state occurs in which the torque to be applied is not transmitted to the output shaft,
In this state, the hydraulic pressure is removed from the piston chamber of the primary pulley, and while sliding the primary pulley and the belt, the distance between the fixed sheave and the movable sheave is changed to adjust the gear ratio of the continuously variable transmission. A control device that changes to the maximum gear ratio side.

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