JP2001214971A - Continuously variable transmission for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuously variable transmission for an automobile that admits of a shift during a stop and can ensure a smooth start with no fault and anomaly in a shift actuator. SOLUTION: A starting clutch 11 is disposed downstream of a secondary pulley 5 to permit a shift during a stop. A speed of an engine 2 under a criterion value Ne stops the operation of a shift actuator 7 to prohibit an improvident shift and to prevent an overload on the shift actuator 7 resulting from a pinch on a power transmission belt 6 by a primary pulley 4, and anomaly in starting resulting from a sag or slip of the power transmission belt 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a continuously variable transmission for an automobile, and more particularly, to an overspeed or damage to an electric transmission actuator caused by an unreasonable speed change operation, and a smooth start. Related to improvements.

[0002]

2. Description of the Related Art A continuously variable transmission for automobiles comprising a primary pulley, a secondary pulley, a power transmission belt and a speed change actuator, so-called CVT.
(Continuously Variable Transmission) is already known.

In this type of continuously variable transmission for automobiles, a primary pulley and a secondary pulley are configured by combining two discs formed in a thin conical shape so that the apex angles thereof are opposed to each other so as to be opposed to each other. The width of the primary pulley and the secondary pulley, that is, the width of the V groove around which the power transmission belt is wound was changed by moving the two disks constituting each pulley toward and away from each other. The gear ratio between the primary pulley and the secondary pulley is adjusted by regulating the winding radius of the power transmission belt.

That is, when the two disks are brought closer to each other to reduce the width of the pulley, the width of the groove around which the power transmission belt is wound is reduced, and the wedge effect of the V-groove formed on the opposing surface of each disk is used. Conversely, if the power transmission belt moves radially outward of the pulley and the two disks are separated from each other to increase the width of the pulley, the groove width around which the power transmission belt is wound increases. The power transmission belt moves radially inward of the pulley along the V-groove formed on the opposing surface of each disk.

[0005] In speed change operation, it is common to change the width of the primary pulley and the width of the secondary pulley in the opposite direction to adjust the speed ratio. For example, when it is desired to increase the speed ratio, the width of the primary pulley is increased. In order to reduce the width of the secondary pulley and reduce the gear ratio, a cooperative operation such as reducing the width of the primary pulley and increasing the width of the secondary pulley is performed.

As a mechanism for performing such a cooperative operation, a hydraulic or electric shift actuator for adjusting the width of a primary pulley and discs on both sides of a secondary pulley are urged in a direction of approaching each other. Generally, a combination of a mechanical driven adjustment means, for example, a torque cam is used.

That is, when the width of the primary pulley is increased by operating the speed change actuator and the winding radius of the power transmission belt on the primary pulley side is reduced, the secondary pulley side is reduced by an amount corresponding to the margin of the power transmission belt generated thereby. Is increased, the width of the secondary pulley is automatically narrowed by the urging force of the driven adjustment means described above, and the margin of the secondary pulley on the side of the secondary pulley is reduced to the position of the winding radius allowed by this margin. The power transmission belt is pushed radially outward to perform a downshift. Further, when the width of the primary pulley is reduced by operating the speed change actuator and the winding radius of the power transmission belt on the primary pulley side increases, the winding radius of the power transmission belt on the secondary pulley side is reduced accordingly. Then, the power transmission belt moves radially inward of the secondary pulley while forcibly expanding the width of the secondary pulley against the urging force of the driven adjustment means, thereby performing an upshift.

When this type of continuously variable transmission for automobiles is used, a starting clutch for stopping the vehicle without stopping the engine is provided between the engine and the primary pulley, or between the secondary pulley and the driving wheel. It is possible to arrange between.

[0009]

When a starting clutch is provided between the engine and the primary pulley, when the vehicle runs, that is, when the rotation of the driving wheels stops, the rotation of the primary pulley and the secondary pulley necessarily stops. Therefore, the gearshift operation at the time of stopping the vehicle becomes impossible due to the structure. This is because the stop of the rotation of the primary pulley and the secondary pulley hinders the radial movement of the power transmission belt.

When such a configuration is applied, if the vehicle is suddenly stopped from a state where the continuously variable transmission for the vehicle is upshifting, the drive wheels are stopped before the gear ratio is sufficiently downshifted. Sometimes. However, as described above, the gear ratio cannot be adjusted when the vehicle is stopped, so when starting the car again, the same gear ratio as when the vehicle is stopped, that is, the gear ratio on the upshift side, must be used. Starting from a stopped state may be difficult.

In order to solve such a problem, an auxiliary transmission gear mechanism for compensating for insufficient torque at the time of starting is provided, and the driving torque of the engine is transmitted to the secondary pulley via the auxiliary transmission gear mechanism to start the vehicle. The proposed method is proposed in Japanese Patent Application Laid-Open No. Hei 9-114415, but problems remain in terms of complexity of the structure, increase in weight and manufacturing cost.

On the other hand, in the vehicle in which the starting clutch is provided between the secondary pulley and the drive wheel, even if the vehicle stops and the rotation of the drive wheel stops, the primary pulley is provided as long as the engine itself does not stop. Since the rotation of the secondary pulley and the rotation of the secondary pulley are maintained, there is a merit that a shift operation can be performed when the vehicle is stopped.

However, even when such a configuration is applied, if the engine itself stops, the rotations of the primary pulley and the secondary pulley stop.
Execution of the gear change operation becomes impossible.

In the case where the width of the primary pulley is adjusted by using a hydraulic shifting actuator, the operation of the hydraulic circuit is stopped with the stop of the engine. There is no need to worry about the shifting actuator being easily operated. However, when using an electric shift actuator, the drive control of the shift actuator based on the shift command by manual operation is permitted unless the ignition key is completely returned to the OFF position and the power is turned off. When the primary pulley or secondary pulley is stopped, an excessive shift operation is performed and an excessive load is applied to the shift actuator, or the engagement relationship between the primary pulley and the power transmission belt is not suitable for starting. May change.

For example, when a shift command is issued in a direction to reduce the width of the primary pulley in a state where the engine is stopped, an excessive current flows while the shift actuator is locked with the power transmission belt interposed therebetween, and the shift actuator is locked. And its drive circuit may be damaged. Also,
If a speed change command is issued in the direction in which the width of the primary pulley is increased while the engine is stopped, the power transmission belt wound between the primary pulley and the secondary pulley becomes slack, and the primary pulley is pulled when the vehicle starts. There is also a possibility that the primary pulley idles due to slippage between the power transmission belt and the vehicle and it becomes difficult to start.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned drawbacks and to make it possible to perform a shift operation when the vehicle is stopped, and to perform a shift operation even when the engine is stopped. Provided is a continuously variable transmission for a vehicle that can smoothly start without causing damage to an electric transmission actuator or causing an abnormality in an engagement relationship between a primary pulley and a power transmission belt. It is in.

[0017]

SUMMARY OF THE INVENTION The present invention provides a primary pulley provided at a position closer to an engine on a power transmission system from an engine to a driving wheel, and a primary pulley provided at a position closer to the driving wheel on the power transmission system. A deployed secondary pulley,
A power transmission belt wound between a primary pulley and a secondary pulley, and an electric motor for adjusting a winding radius of the power transmission belt in the primary pulley by changing a width of the primary pulley based on a given shift command. A variable speed actuator and the winding radius of the power transmission belt in the secondary pulley are adjusted by energizing the secondary pulley in a direction to reduce the width, thereby following the change in the winding radius of the power transmission belt in the primary pulley. A continuously variable transmission for an automobile, comprising: a driven clutch that is disposed between the secondary pulley and the drive wheel, and is located upstream of the started clutch. Speed detection means for detecting the speed of the power transmission system A shiftable rotational speed storage unit that stores a rotational speed as a determination value, and determines whether the rotational speed detected by the rotational speed detection unit has reached the determination value stored in the shiftable rotational speed storage unit. A shift enable state determination unit that outputs a shift instruction to the shift actuator when the determination result by the shift enable state determination unit is true; and outputs a shift instruction when the determination result is false. And an actuator operation restricting means for inhibiting the operation.

As described above, since the starting clutch is provided between the secondary pulley and the drive wheel, the rotation of the primary pulley and the secondary pulley is maintained even if the engine is stopped even if the vehicle stops, and the vehicle is stopped. The shift operation in the state can be performed. Further, when the vehicle is stopped, the engine is operated, and only when the rotation speed of the power transmission system located upstream of the starting clutch has reached the rotation speed at which the shift operation can be performed, a shift command to the shift actuator is transmitted. Since the output is allowed, excessive current flows when the speed change actuator is locked with the power transmission belt in between, which may damage the actuator and the drive circuit, or the width of the primary pulley may be inadvertently reduced. The problem of spreading is eliminated. Therefore, no slippage occurs between the primary pulley and the power transmission belt at the time of starting, and a smooth start can be achieved.

It is desirable that the shiftable rotational speed storage means stores a rotational speed equal to or lower than the rotational speed of the power transmission system when the engine is idling as a determination value.

This is because if a rotational speed exceeding the idling speed is stored as a judgment value, the speed change operation during normal running is hindered. The rotational speed that can be used as the judgment value is basically a value that is greater than zero and equal to or less than the idling speed. However, a certain load acts on the engine even by shifting operation by adjusting the primary pulley, for example, by upshifting. In addition, since the idling speed also fluctuates depending on the environmental temperature and the like, in order to increase the degree of freedom of the shifting operation in a stopped state and prevent inadvertent engine stoppage, the engine is actually operated even when the shifting operation is performed. Should be set as small as possible so as not to stop. It is also possible to provide a shiftable rotational speed storage unit storing a plurality of determination values corresponding to the environmental temperature and an environmental temperature detecting unit, and to read the determination value to be used according to the environmental temperature. .

As the shiftable rotation speed storage means, for example, a rotation detector for detecting the rotation speed of an engine, a primary pulley or a secondary pulley can be used. In addition, the rotating element of the power transmission system located upstream of the starting clutch, more strictly, any rotating element located in the power transmitting system in the section from the output shaft of the engine to the input shaft of the starting clutch. By attaching a rotation detector, it is possible to use as a shiftable rotation speed storage means.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram schematically showing a main part of a continuously variable transmission 1 for an automobile according to an embodiment to which the present invention is applied.

The mechanical components of the continuously variable transmission 1 for an automobile are, as shown in FIG.
A primary pulley 4 provided at a position closer to the engine 2 on the power transmission system from the drive wheel 3 to the drive wheel 3, a secondary pulley 5 provided at a position closer to the drive wheel 3, and the primary pulley 4 and the secondary pulley 5 A power transmission belt that is wound in between, and an electric transmission that adjusts the winding radius of the power transmission belt 6 in the primary pulley 4 by changing the width of the primary pulley 4 based on a given shift command. Actuator 7 and a torque cam 8 functioning as a driven adjustment means for the secondary pulley 5.

Of these, the primary pulley 4 is constructed by combining two discs 4a and 4b formed in a thin conical shape so that the apex angles thereof are opposed to each other so that they can be separated from each other. The distance, that is, the width of the primary pulley 4 is adjusted by an electric shifting actuator 7.

The secondary pulley 5 is constituted by combining two discs 5a and 5b formed in a thin conical shape so that their apical angles are opposed to each other so as to be able to come and go, and each of the discs 5a and 5b is Secondary pulley 5
Are biased in a direction approaching each other, that is, a direction in which the width of the secondary pulley 5 is reduced. The function of the torque cam 8 itself has already been described in Japanese Patent Application Laid-Open No. H10-5442.
No. 9, etc., and the description is omitted.

The electric shift actuator 7 for adjusting the width of the primary pulley 4 is, for example, a disk 4a.
A shaft 7a in which the disk 4b is fixed so that it cannot rotate and cannot move in the axial direction, and the disk 4b is splined so that it cannot rotate and can move in the axial direction. And a feed screw 7c screwed into the sleeve 7b and fixed to the transmission body, and a sleeve 7 with respect to the feed screw 7c.
It is possible to use a motor 7d for relatively rotating b. In short, the rotation of the motor 7d applies an axial feed to the sleeve 7b to move the disk 4b along the shaft 7a.
4b, that is, the width of the primary pulley 4 is adjusted.

As shown in FIG. 1, an output shaft 2a of the engine 2 and the primary pulley 4 are connected via a gear train 9 so as to be capable of transmitting power.
The drive wheel 3 is connected so as to be able to transmit power via a gear train 10, a starting clutch 11 and a timing belt 12. That is, the secondary pulley 5 and the driving wheel 3
, The starting clutch 11 is provided. Therefore, when referring to the power transmission system located on the upstream side of the starting clutch 11 here, all components from the output shaft 2a of the engine 2 to the input shaft 11a of the starting clutch 11, that is, the output shaft 2a , Gear train 9, primary pulley 4, secondary pulley 5, gear train 10, and input shaft 11a.

In the above configuration, the motor 7d, which constitutes the main part of the electric shifting actuator 7, is driven to feed the sleeve 7b in the direction of increasing the engagement with the feed screw 7c, and the primary pulley 4 When the width is increased, the groove width of the primary pulley 4 is increased, and the power transmission belt 6 on the primary pulley 4 side
B moves radially inward of the primary pulley 4 along the conical slope of b, and the winding radius of the power transmission belt 6 on the primary pulley 4 side decreases. The winding radius of the power transmission belt 6 on the side of the secondary pulley 5 is allowed to increase by an amount corresponding to the margin of the power transmission belt 6 caused by the reduction of the winding radius. The width is automatically reduced, and the power transmission belt 6 on the secondary pulley 5 side is moved to the position of the winding radius allowed by this allowance.
a, 5b along the conical slope
Extruded radially outward. By this operation, a direction in which the speed ratio between the primary pulley 4 and the secondary pulley 5 increases, that is, a downshift speed change operation is achieved.

On the other hand, the motor 7d is driven to drive the sleeve 7b
When the width of the primary pulley 4 is reduced by applying a feed in a direction to make the screw engagement with the feed screw 7c shallow, the groove width of the primary pulley 4 is reduced, and the power transmission belt 6 on the primary pulley 4 side becomes It moves radially outward of the primary pulley 4 along the conical slopes of the disks 4a, 4b, and the winding radius of the power transmission belt 6 on the primary pulley 4 side increases. Then, the winding radius of the power transmission belt 6 on the secondary pulley 5 side decreases by an amount corresponding to the shortage of the power transmission belt 6 caused by the increase in the winding radius, and the power transmission belt 6 on the secondary pulley 5 side
It moves radially inward of the secondary pulley 5 while widening the distance between the disks 5a and 5b against the urging force of the torque cam 8. By this operation, the gear ratio between the primary pulley 4 and the secondary pulley 5 decreases,
That is, the upshift speed change operation is achieved.

As shown in FIG. 1, the engine 2 is provided with a throttle opening sensor 13.
An engine rotation sensor 14 for detecting the engine speed is provided at a position facing the output shaft 2a. In the present embodiment, the engine rotation sensor 14
It functions as rotation speed detection means for detecting the rotation speed of the power transmission system located upstream of the start clutch 11.

Further, a vehicle speed sensor 16 for detecting the running speed of the vehicle is provided at a position facing the output shaft 11b of the starting clutch 11, and a probe is provided on the end face of the disk 4b constituting a part of the primary pulley 4. The pulley position sensor 17 is provided so as to slide.

As is apparent from the above description of the operation of the mechanical components, the gear ratio between the primary pulley 4 and the secondary pulley 5 is determined by the width of the primary pulley 4, that is, the speed ratio between the disks 4a and 4b. The value corresponding to the speed ratio can be detected by the pulley position sensor 17 as the distance between the disk 4a and the disk 4b.

The secondary pulley sensor 21 is a detecting means for detecting the rotational speed of the secondary pulley 5.

Reference numeral 18 shown in FIG. 1 is a manual mode switch for selecting one of an automatic shift mode and a manual shift mode. When the manual mode switch is ON, the manual shift mode is Further, when the manual mode switch is OFF, the automatic shift mode is selected.

Reference numerals 19 and 20 denote an upshift switch and a downshift switch for manual shifting, respectively, and operation is permitted only when the manual mode switch 18 is turned on. These switches 1
8, 19, and 20 are provided near the steering wheel in the case of a two-wheeled vehicle such as a scooter, and are substituted by a shift lever or the like in the case of a four-wheeled vehicle.

FIG. 2 is a block diagram schematically showing a configuration of the control unit 22 provided in the continuously variable transmission 1 for a vehicle according to the present embodiment. The main part of the control unit 22 includes a CPU 23 as an arithmetic unit, a RAM 24 used for temporary storage of arithmetic data, a ROM 25 as a storage unit for determination values, various data, operation programs, and the like. As shown in FIG. 2, the various sensors 13, 14,
Signals from the switches 16, 17, and 21 and the switches 18, 19, and 20 are input to the CPU 2 of the control unit 22 through an input circuit 26.
3 is input. The motor 7 d and the starting clutch 11, which are components of the electric speed change actuator 7, are also provided.
Are controlled by the respective drive circuits 28 and 29 in response to a command from the CPU 23 output via the output circuit 27, and the clutch 11 is turned off (disconnected state) when the vehicle stops. ON when the vehicle is running
(Connected state).

An outline of the processing functions of the CPU 23 is shown in a functional block diagram of FIG. The CPU 23 stores a rotational speed detected by the engine rotation sensor 14 constituting a rotational speed detecting means in a ROM 25 as a shiftable rotational speed storing means.
Shiftable state determination means for determining whether or not the determination value stored in the shift register 7 has been reached, and an actuator operation for limiting the output of a shift command to the motor 7d of the shift actuator 7 according to the determination result Functions as a limiting means. A function as target gear ratio setting means for calculating an optimal gear ratio based on signals from the vehicle speed sensor 16 and the throttle opening sensor 13 and signals from the upshift switch 19 and the downshift switch 20;
The CPU 23 also realizes a function as actual speed ratio detecting means for obtaining a speed ratio currently set between the primary pulley 4 and the secondary pulley 5 based on a signal from the pulley position sensor 17. .

Next, with reference to a flowchart of the actuator driving process shown in FIG. 4, an outline of a process related to a shift operation among processing operations of the CPU 23 constituting a main part of the control unit 22 will be described. This process is repeatedly executed by the CPU 23 every predetermined processing cycle.

CPU that has started the actuator drive processing
Reference numeral 23 denotes a throttle opening sensor 13, a vehicle speed sensor 16, and an engine rotation sensor 1 as rotation speed detecting means.
4. Through each of the pulley position sensors 17, the current value of the throttle opening in the engine 2, the current value of the vehicle running speed, the current value of the engine rotation speed, and the current axial position of the disk 4b with respect to the feed screw 7c are detected. (Step a1 to step a4).

Next, C as a shiftable state determination means
PU23 is a ROM as a shiftable rotational speed storage means
25, the current value of the engine rotational speed read in the process of step aa3 is set to the determination value N.
e is determined (step a5).

In the present embodiment, since the engine speed sensor 14 is used as a rotation speed detecting means for detecting the rotation speed of the power transmission system, the value of the judgment value Ne is determined by the engine 2 during idling. The value equal to or somewhat lower than the rotation speed is ROM
25 is set. If a value larger than the idling speed is set as the determination value Ne, the driving of the speed change actuator 7 is restricted even in a situation where the vehicle is running, so the value larger than the idling speed is determined. It must not be used as the value Ne. Conversely, if the value is equal to or greater than zero and smaller than the idling speed, basically any value may be used as the determination value Ne. In order not to stop the engine, it is necessary to set a rotation speed at which the rotation of the engine can be maintained even with a certain degree of torque fluctuation. It is desirable that an appropriate value of the determination value Ne is obtained by an experiment or the like.

Further, the idling value varies depending on the temperature of the engine cooling water, the environmental temperature, and the like. Determination values Ne1, Ne
, 2, Ne3,... Are stored in the ROM 25, and an appropriate determination value Nex may be selectively used based on data from a water temperature sensor of the engine cooling water or environmental temperature detecting means. In this case, the reading of the temperature data from the water temperature sensor and the environmental temperature detecting means is executed together with the processing of steps a1 to a4, and the selection processing of the judgment value Nex is executed together with the processing of step a5.

The rotation speed of the primary pulley 4 and the rotation speed of the secondary pulley 5 are replaced with the rotation speed of the engine 2.
Is detected and compared with the rotation speed Ne 'of the primary pulley 4 and the rotation speed Ne "(judgment value) of the primary pulley 4 and the rotation speed Ne" (judgment value) corresponding to values equal to or lower than the engine idling speed. Further, the same processing is performed by detecting the rotation speed of any of the gears constituting the gear train 9 or the gear train 10 or the input shaft 11a of the starting clutch 11. In short, any portion of the rotating element on the power transmission system that operates together with the engine 2 even when the vehicle is stopped may be provided with the rotating speed detecting means.

Here, if the result of the determination at step a5 is true, that is, if it is determined that the transmission actuator 7 can be driven, the CPU 23 as the target gear ratio setting means proceeds to step a5. If the throttle opening read in the process of a1, that is, the load acting on the engine 2, the data of the running speed of the vehicle read in the process of step a2, and the upshift switch 19 or the downshift switch 20 is operated, The gear ratio most suitable for the current application is calculated in consideration of the upshift and downshift commands, and temporarily stored as the target gear ratio (step a6).

Next, a CPU as actual speed ratio detecting means is used.
23 is the disk 4b read in the process of step a4
Then, the value of the gear ratio currently used at the present time is calculated based on the current axial position, and the value is temporarily stored (step a7). As described above, the gear ratio between the primary pulley 4 and the secondary pulley 5 is the same as that of the disk 4a.
It can be calculated based on the detection value of the pulley position sensor 17 that detects the separation distance between the disk and the disk 4b.

Then, the CPU 23 as the actuator operation restricting means obtains a deviation between the target speed ratio calculated in the process of step a6 and the actual speed ratio calculated in the process of step a7 and its directionality. The drive amount and directionality of the motor 7d required to solve the problem are calculated (step a8), and the drive circuit 2 is driven based on the drive amount and directionality.
8, a motor drive command as a shift command is output.
The drive of the electric shift actuator 7 constituting the main part is controlled by d to adjust the width of the primary pulley 4 and set a predetermined gear ratio, that is, a target gear ratio calculated in the process of step a6. (Step a9).

When the result of the determination in step a5 is true, the primary pulley 4 and the secondary pulley 5 move the power transmission belt 6 radially in and out, whether the vehicle is running or stopped. Since the rotation is performed at a speed sufficient to smoothly move the disk, even if the actuator 7 is driven in the direction of reducing the width of the primary pulley 4 (upshift side), the disks 4a and 4b are not rotated.
Does not inadvertently pinch and lock the power transmission belt 6, and therefore, there is no problem that an excessive load acts on the motor 7d or an excessive current flows.

When the actuator 7 is driven in the direction in which the width of the primary pulley 4 is increased (downshift side), the power transmission belt 6 follows the expansion of the width of the primary pulley 4 to be surely positioned radially inward. The power transmission belt 6 or the torque cam 8 may cause the power transmission belt 6 to loosen unintentionally, or the power transmission belt 6 may slide between the primary pulley 4 and the primary pulley 4. Also does not occur.

Since the value of the judgment value Ne is set lower than the idling speed, even if the engine 2 is rotating normally even in the idling state where the vehicle is stopped, the upshift switch 19 is set. By operating the downshift switch 20 or the downshift switch 20, the upshift or downshift speed change operation can be freely performed.

Further, since the value of the determination value Ne is set to a rotational speed at which a torque output that does not cause engine stalling even when the gearshift operation is performed is possible, the determination operation Ne is performed when the gearshift operation is performed while the vehicle is stopped. However, the engine 2 is not inadvertently stopped.

On the other hand, if the result of the determination in step a5 is false, the rotational speed of the power transmission system is low, and it is difficult to adjust the width of the primary pulley 4 by driving the shift actuator 7, or This means that the engine 2 is completely stopped and the width of the primary pulley 4 cannot be adjusted, or is in any state.

In this case, the CPU 23 as the actuator operation restricting means does not execute the processing of steps a6 to a9, prohibits the driving of the motor 7d, and holds the shifting actuator 7 at the previous position (step a10). ).

Therefore, for example, if the driver accidentally operates the upshift switch 19 or the downshift switch 20 with the engine 2 stopped, the motor 7
d does not work in either direction.

Thus, the problem that the discs 4a and 4b inadvertently sandwich the power transmission belt 6 with the engine 2 stopped and an excessive load acts on the motor 7d is solved, and the width of the primary pulley 4 is reduced. It is also possible to prevent the power transmission belt 6 and the primary pulley 4 from being inadvertently spread and causing slippage between the power transmission belt 6 and the primary pulley 4 and hindering the start of the next engine start.

There are various methods for controlling the drive of the speed change actuator 7, but when the motor 7d is driven by simple ON / OFF control, the energization itself to the motor 7d is stopped in the process of step a10. If the closed loop control for the target gear ratio is performed using a position command or the like, step a
In the process of step 10, the output of the movement command for eliminating the deviation amount may be stopped. In the latter case, even if the output of the position command is stopped, the feedback control of the position loop is continuously performed, and if a position deviation or the like occurs due to the action of the external force, the error value of the position deviation counter changes to change the current position. A drive command for holding is given, but this is not a movement command for a shift operation but a command for holding the current position.

[0056]

According to the continuously variable transmission for an automobile of the present invention, a start clutch is provided between the secondary pulley and the drive wheels. Operations can be performed.

Further, the output of the shift command to the shift actuator is permitted only when the rotation speed of the power transmission system located upstream of the starting clutch has reached the rotation speed at which the shift operation is possible. Therefore, an unreasonable shifting operation is not performed in a situation where the shifting operation is difficult, and an overload of the shifting actuator is prevented.

Further, since the width of the primary pulley is not inadvertently widened in a state where the gearshift operation cannot be substantially performed, the problem that slippage occurs between the primary pulley and the power transmission belt at the time of starting is solved. And a smooth start is possible.

The adoption of an electric shifting actuator using a motor or the like has the advantage that the structure is simpler than that of the hydraulic type and the maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a schematic view schematically showing a main part of a continuously variable transmission for an automobile according to an embodiment to which the present invention is applied.

FIG. 2 is a block diagram schematically illustrating a configuration of a control unit provided in the continuously variable transmission for a vehicle according to the embodiment.

FIG. 3 is a functional block diagram schematically showing processing functions of a CPU constituting a main part of a control unit.

FIG. 4 is a flowchart showing an outline of an actuator driving process.

[Explanation of symbols]

 Reference Signs List 1 continuously variable transmission for automobile 2 engine 2a output shaft 3 drive wheel 4 primary pulley 4a, 4b disk 5 secondary pulley 5a, 5b disk 6 power transmission belt 7 electric type shift actuator 7a shaft 7b sleeve 7c feed screw 7d motor 8 Torque cam (driven adjustment means) 9 Gear train 10 Gear train 11 Start clutch 11a Input shaft 11b Output shaft 12 Timing belt 13 Throttle opening sensor 14 Engine rotation sensor (rotation speed detection means) 16 Vehicle speed sensor 17 Pulley position sensor 18 Manual mode switch Reference Signs List 19 upshift switch 20 downshift switch 21 secondary pulley sensor 22 control unit 23 CPU 24 RAM 25 ROM 26 input circuit 27 output circuit 28 drive circuit 29 drive circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J052 AA04 AA09 AA17 CA18 CA21 CB01 CB16 GC03 GC13 GC23 GC43 GC44 GC46 HA11 KA01 LA01

Claims (5)

[Claims] A primary pulley disposed at a position closer to the engine on a power transmission system from the engine to the drive wheels; a secondary pulley disposed at a position closer to the drive wheels on the power transmission system; A power transmission belt wound between a primary pulley and the secondary pulley, and a winding radius of the power transmission belt in the primary pulley adjusted by changing a width of the primary pulley based on a given shift command. An electric transmission actuator, and the secondary pulley is urged in a narrowing direction to be driven by a change in a winding radius of the power transmission belt in the primary pulley, thereby winding the power transmission belt in the secondary pulley. A continuously variable transmission for an automobile having a driven adjusting means for adjusting a turning radius. A start-up clutch disposed between the secondary pulley and the drive wheel, and a rotational-speed detecting means for detecting a rotational speed of a power transmission system located upstream of the start-up clutch; A shiftable rotation speed storage unit that stores a speed as a determination value, and a shift that determines whether the rotation speed detected by the rotation speed detection unit has reached the determination value stored in the shiftable rotation speed storage unit. An output unit for outputting a shift command to the shift actuator when the determination result by the possible state determination unit and the shift possible state determination unit is true, and outputting the shift command when the determination result is false. A continuously variable transmission for an automobile, comprising a prohibiting actuator operation restricting means. 2. The vehicle according to claim 1, wherein the shiftable rotational speed storage means stores a rotational speed equal to or lower than a rotational speed of a power transmission system when the engine is idling as a determination value. Continuously variable transmission. 3. The rotation speed detection means comprises a rotation detector for detecting the rotation speed of the engine, and the shiftable rotation speed storage means determines a rotation speed equal to or less than the rotation speed of the engine during idling. 3. The continuously variable transmission according to claim 2, wherein the transmission is stored as a value. 4. The rotation speed detecting means comprises a rotation detector for detecting a rotation speed of the primary pulley, and the shiftable rotation speed storage means stores a rotation speed of the primary pulley when the engine is idling. 3. The continuously variable transmission according to claim 2, wherein the following rotational speeds are stored as the determination values. 5. The rotational speed detecting means comprises a rotational detector for detecting a rotational speed of the secondary pulley, and the shiftable rotational speed storage means stores a rotational speed of the secondary pulley when the engine is idling. 3. The continuously variable transmission according to claim 2, wherein the following rotational speeds are stored as the determination values.