JP2020076443A - Controller of continuously variable transmission for vehicle - Google Patents

Abstract

To suppress belt slippage resulting from the twisting of a drive shaft in vehicle stop using a braking device, in a vehicle mounted with a belt type continuously variable transmission.SOLUTION: Restriction mechanisms 36, 38, 42 that suppress the transmission of rotational power resulting from the twist of a drive shaft 7 from the drive shaft 7 to a secondary pulley 16 are provided. When a vehicle speed is below a predetermined speed or a vehicle is stopped during braking by a braking device 9, the restriction mechanisms 36, 38, 42 are operated so as to suppress the transmission of the rotational power.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for a vehicle continuously variable transmission that prevents belt slip (or chain slip) that occurs when the vehicle is stopped.

In a belt type continuously variable transmission (hereinafter also referred to as a CVT) mounted on a vehicle, slippage between a pulley and a belt (or a chain; hereinafter typically referred to as a belt) is suppressed in order to maintain durability. This is very important.
In particular, since belt slippage is likely to occur during vehicle braking, a technique for suppressing it is known (Patent Document 1). According to this technique, it is possible to suppress belt slip that occurs during braking before the vehicle is stopped.

JP, 2012-36949, A

The drive shaft of the vehicle is twisted due to the drive torque, and the twist becomes large during braking (even larger during sudden braking). Then, at the same time as or immediately after the vehicle stops (hereinafter, collectively referred to as “at the time of stopping”), the drive shaft rotates in a direction to eliminate the twist due to its own elastic force, but this rotation reverses the output pulley of the CVT. It is input in the direction and becomes a factor that causes belt slip.
Normally, the drive shaft is drivingly connected to the output pulley via a reduction gear having a large gear ratio (for example, 5.0 to 6.5), so that the output pulley can be driven even if the twist angle of the drive shaft is small. The belt is rotated in the reverse direction greatly, and the belt slip amount increases.
In particular, in a CVT using a push belt in which a large number of elements are aligned along a ring, a large gap is generated between elements due to belt slip caused by twisting of a drive shaft when the vehicle is stopped, and an engaging portion between the elements is generated. If the large gap is not eliminated due to deviation of the belt or the like, it may cause damage to the belt due to loss of the element or breakage of the ring.
Further, even in a CVT using a chain, the slip may damage the surface of the pulley, which may cause a decrease in durability.

  The present invention was devised in view of the above problems, and provides a control device for a continuously variable transmission for a vehicle that suppresses reverse rotation of an output pulley when the vehicle is stopped due to twisting of a drive shaft. Has a purpose.

(1) In order to achieve the above object, a control device for a continuously variable transmission for a vehicle according to the present invention includes: an input pulley connected to a drive source; an output pulley connected to a drive shaft; In a vehicle including a continuously variable transmission having an endless flexible member and a braking device that brakes the rotation of the drive shaft, a vehicle speed detecting unit that detects a traveling speed of the vehicle, and an operation of the braking device. A braking detection unit that detects a state, a limiting mechanism that suppresses transmission of rotational power due to a twist of the drive shaft from the drive shaft to the output pulley, and a predetermined speed determined by the vehicle speed detection unit during braking by the braking device. It is characterized in that it is provided with a limiting mechanism operating means for operating the limiting mechanism so as to suppress the transmission of the rotational power when a vehicle speed or less or a vehicle stop is detected.
(2) It is preferable that the limiting mechanism includes a parking mechanism that fixes the rotation of the output pulley, and an actuator that is controlled by the limiting mechanism operating means to operate the parking mechanism.
(3) It is preferable that a first clutch that connects and disconnects the drive source and the input pulley is provided, and the first clutch is released after the actuator is operated by the limiting mechanism operating means.

  (4) Further, it is preferable that the limiting mechanism is a second clutch that is operated and controlled by the limiting mechanism actuating means and that connects and disconnects the drive connection between the drive shaft and the output pulley.

  According to the present invention, the limiting mechanism that suppresses the transmission of rotational power due to the twist of the drive shaft from the drive shaft to the output pulley, and the limiting mechanism when a vehicle speed equal to or lower than a predetermined vehicle speed or a vehicle stop is detected during braking by the braking device. Since the limiting mechanism actuating means for actuating the transmission of the rotational power is provided, the reverse rotation of the output pulley due to the twisting of the drive shaft when the vehicle is stopped is suppressed, and the occurrence of belt slip is prevented. You can

It is a typical block diagram which shows the control apparatus of the continuously variable transmission for vehicles concerning 1st embodiment of this invention. It is a flow chart explaining operation of a control device of a vehicular continuously variable transmission concerning a first embodiment of the present invention. It is a typical block diagram which shows the control apparatus of the continuously variable transmission for vehicles concerning 2nd embodiment of this invention. It is a flowchart explaining operation | movement of the control apparatus of the continuously variable transmission for vehicles concerning 2nd embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
Note that the embodiments described below are merely examples, and there is no intent to exclude various modifications and application of techniques that are not explicitly shown in the following embodiments.

As shown in FIG. 1, to a vehicle to which the first embodiment of the present invention is applied, a drive source 2 of a vehicle such as an internal combustion engine or an electric motor, and a rotational drive force from the drive source 2 are output after being changed in speed. A belt-type continuously variable transmission (CVT) 4, a reduction mechanism 10 for decelerating an output from the CVT 4 and transmitting it to a drive wheel 8 via a differential mechanism 6 and a drive shaft 7, and braking of rotation of the drive shaft 7. A braking device 9 having a well-known configuration (only the wheel braking mechanism representing the braking device is shown in the drawing) is mounted.
The CVT 4 includes a primary pulley (input pulley) 14 drivingly connected to the input shaft 12 connected to the drive source 2 via the first clutch 13, and a secondary pulley drivingly connected to the reduction mechanism 10 via the output shaft 15. (Output pulley) 16 and an endless flexible member such as a belt or a chain that is sandwiched between V-shaped grooves 18 and 20 formed in both pulleys 14 and 16 and is wound between both pulleys 14 and 16 (hereinafter referred to as an endless flexible member). , 22).

  As is well known, the CVT 4 is configured to control the gear ratio by changing the widths of the grooves 18 and 20 of the pulleys 14 and 16 by hydraulic pressure. A hydraulic pressure controlled by a hydraulic control device 26 controlled by an ECU 24) is supplied. Further, the hydraulic control device 26 is supplied with hydraulic oil as the original pressure from an oil pump 28 driven by the drive source 2.

The hydraulic control device 26 is provided with a solenoid valve (not shown) for controlling the output hydraulic pressure, and the ECU 24 detects the vehicle speed sensor (vehicle speed detecting means) 30 for detecting the traveling speed of the vehicle and the opening degree of the accelerator pedal. The gear ratio and supply hydraulic pressure of the CVT 4 are calculated using the detection signal from the accelerator sensor 32, etc., and the solenoid valve is controlled based on the result to control the output hydraulic pressure, and finally the gear ratio of the CVT 4 and It is configured to control the disengagement of the first clutch 13.
In addition, a signal from a braking sensor (braking detection means) 34 that detects the amount of depression of a brake pedal (not shown) and detects the operating state of the braking device 9 is input to the ECU 24.

  The fixed pulley 17 of the secondary pulley 16 fixedly connected to the output shaft 15 is provided with a parking mechanism 36 having a well-known structure that mechanically stops the rotation of the output shaft 15 (fixed pulley 17). It is configured to be operated by an electric actuator 38 controlled by the ECU 24, and the parking mechanism 36 and the actuator 38 limit the transmission of rotational power to the secondary pulley 16 due to the twist of the drive shaft 7. It functions as a mechanism.

  In the first embodiment, in the above configuration, the belt 22 is prevented from slipping when the vehicle is stopped due to the twist of the drive shaft 7 that occurs during braking by the braking device 9. The limiting mechanism operating means 40 for operating the parking mechanism 36 to stop the rotation of the secondary pulley 16 at times is incorporated, and the ECU 24 controls the hydraulic control device 26 (the first clutch 13 based on the action of the limiting mechanism operating means 40). ) And the actuator 38.

Next, in the ECU 24 of the CVT 4 having the above configuration, the configuration of the limiting mechanism operating means 40 that operates the parking mechanism 36 when the vehicle is stopped will be described with reference to the flowchart shown in FIG.
This flow chart (that is, the content of the control by the limiting mechanism actuating means 40) is repeatedly executed at a predetermined cycle when the ignition (or the ignition key) of the vehicle is on.

First, in step S01, signals from the vehicle speed sensor 30 and the braking sensor 34 are input to detect the vehicle speed and the operating state of the braking device 9.
Next, in step S02, it is determined whether or not the braking device 9 is operating, and if NO, the process ends.
On the other hand, if the result of step S02 is YES, the process proceeds to step S03, and it is determined whether or not the vehicle has stopped based on the signal of the vehicle speed sensor 30 detected in step S01. If the determination result is NO, the process is performed. finish.

  On the other hand, if the determination result in step S03 is YES, that is, if it is detected that the vehicle has stopped, in step S04, the parking mechanism 36 (actuator 38) is operated to mechanically stop the rotation of the secondary pulley 16, and further step In S05, the hydraulic control device 26 is controlled to release the first clutch 13.

The first clutch 13 is released by rotating the driving mechanism 7 when the parking mechanism 36 is released in preparation for the next start after the vehicle is stopped. This is because, if there is no rotational load on the CVT 4, the pulleys 14 and 16 and the belt 22 rotate following the rotational power without resistance, so that belt slip does not occur.
The first clutch 13 may be configured to be released by not the limiting mechanism actuating means 40 but a conventionally known neutral idle control means that detects the stop of the vehicle and achieves the neutral state.

  According to the first embodiment of the present invention having the above configuration, when the vehicle is stopped by braking (simultaneously with or immediately after stopping), the parking mechanism 36 is operated to mechanically stop the rotation of the secondary pulley 16, It is possible to prevent transmission of rotational power to the secondary pulley 16 due to the twist of the drive shaft 7 and reliably prevent belt slippage.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 3 and 4, but the same or substantially the same configurations as those of the first embodiment will be designated by the same reference numerals and description thereof will be omitted.

In the second embodiment, a second clutch 42 capable of connecting and disconnecting the drive connection between the secondary pulley 16 and the reduction mechanism 10 is provided as a limiting mechanism. The operation of the second clutch 42 is also controlled by the hydraulic control device 26 that receives an instruction from the ECU 24. Further, the parking mechanism 36 may have a known structure that is mechanically connected to the shift lever.
The structure of the limiting mechanism operating means 40 'having the above structure will be described with reference to the flowchart shown in FIG.

Steps S01 and S02 are the same as those in the first embodiment. In step S03 ′, it is determined whether the vehicle speed is not higher than a predetermined value instead of stopping the vehicle. This predetermined value is a vehicle speed (for example, 5 km / h) on the verge of stopping the vehicle, and is substantially the same as detecting the vehicle stop.
Then, if the vehicle speed is equal to or lower than the predetermined value, the second clutch 42 is released in step S06, and the process ends.

  According to the second embodiment of the present invention having the above configuration, the second clutch 42 is released just before the vehicle stops, so that the transmission of the rotational power due to the twist of the drive shaft 7 to the secondary pulley 16 is released. It is blocked by the second clutch 42 (only the drive shaft 7 rotates in the direction to eliminate the twist), and the belt slip can be surely prevented.

Although the embodiment of the present invention has been described above, the present invention can be implemented by appropriately modifying the embodiment.
For example, although the electric actuator 38 is used to operate the parking mechanism 36 in the first embodiment, a hydraulic actuator may be used.
Further, in the case of a CVT in which a forward / reverse switching mechanism is interposed between the drive source 2 and the primary pulley 14, a clutch used in the same forward / reverse switching mechanism can be used as the first clutch 13.
Further, in the case of a CVT in which a stepped type auxiliary transmission using a planetary gear is interposed between the secondary pulley 16 and the reduction mechanism 10, the clutch used in the auxiliary transmission is also used as the second clutch 42. It is possible.
Furthermore, as the vehicle speed detection means, in addition to a general vehicle speed sensor that detects the vehicle speed from the wheel speed and other rotational speeds of the rotating shaft, the vehicle speed estimated from the vehicle speed signal obtained from the GPS device, the operating state of the vehicle, and the like. Any means can be used as long as it can obtain the traveling speed of the vehicle.

2 Drive source 4 CVT (continuously variable transmission)
7 Drive shaft 9 Braking device 13 First clutch 24 ECU (control device)
30 vehicle speed sensor (vehicle speed detection means)
34 Braking sensor (braking detection means)
36 Parking mechanism (restriction mechanism)
38 Actuator (Limiting mechanism)
40, 40 'Limiting mechanism operating means 42 Second clutch (limiting mechanism)

Claims (4)

A continuously variable transmission having an input pulley connected to a drive source, an output pulley connected to a drive shaft, and an endless flexible member wound between the pulleys, and a braking device for braking the rotation of the drive shaft. In a vehicle equipped with
Vehicle speed detection means for detecting the traveling speed of the vehicle,
Braking detection means for detecting the operating state of the braking device,
A limiting mechanism that suppresses the transmission of rotational power due to the twist of the drive shaft from the drive shaft to the output pulley;
A limiting mechanism actuating means for actuating the limiting mechanism so as to suppress the transmission of the rotational power when the vehicle speed detecting means detects a vehicle speed equal to or lower than a predetermined vehicle speed or the vehicle is stopped during braking by the braking device. A control device for a continuously variable transmission for a vehicle. 2. The continuously variable vehicle according to claim 1, wherein the limiting mechanism includes a parking mechanism that fixes the rotation of the output pulley, and an actuator that is controlled by the limiting mechanism operating means to operate the parking mechanism. Transmission control device. A first clutch that connects and disconnects the connection between the drive source and the input pulley;
The control device for a continuously variable transmission according to claim 2, wherein the first clutch is released after the actuator is operated by the limiting mechanism operating means. 2. The continuously variable transmission for a vehicle according to claim 1, wherein the limiting mechanism is a second clutch that is operation-controlled by the limiting mechanism operating means and that connects and disconnects the drive connection between the drive shaft and the output pulley. Control device.

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