JPS63176744A - Belt slip releasing method for v-belt type continuously variable transmission - Google Patents

Abstract

PURPOSE:To eliminate slip by providing a duty control zone for releasing belt slip at a portion higher than an upper limit of duty control zone for speed change control, and outputting a control signal to a solenoid valve when an engine enters into said control zone in order to increase the oil pressure in a hydraulic chamber. CONSTITUTION:A duty control zone for releasing belt slip is provided at a portion higher than an upper limit of duty control for speed change control. Lower limit of said releasing duty control zone is set with reference to an input rotation which can not be achieved through normal speed change control. When oil adheres to V-belt 15 or pulleys 12, 14 and causes belt slip, the input rotation exceeds over the duty control zone for speed change control and enters into the duty control zone for releasing belt slip, thereby it is judged to be slip. A duty ratio is read out from the releasing duty control zone and outputted to a pulley control solenoid 44. Consequently, oil pressure in an oil chamber 18 increases to increase thrust of pulley thus releasing belt slip.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to (1) a belt slip release method for a belt type continuously variable transmission.

Prior art and its problems ■ In a belt-type continuously variable transmission, the applicant provided a thrust loading device that loads the thrust necessary for torque transmission to one of the driving pulley or the driven pulley, and set the gear ratio to the other. A hydraulic chamber for control is provided, and control hydraulic pressure is guided to the hydraulic chamber from a hydraulic control device having an electric valve. Set the duty control range for speed change control that includes the target input revolution speed, and when the actual input revolution number is outside the duty control range, turn on the solenoid valve continuously so that the actual input revolution number falls within the duty control range. V-belt type that realizes smooth gear shifting by outputting a duty control signal to the solenoid valve according to the magnitude of the actual input rotation speed when the actual input rotation speed is within the duty control range. (Refer to Japanese Patent Application No. 173874/1983 for the purpose of proposing a speed change control method for a continuously variable transmission.)

By the way, in the case of a tension-driven V-belt continuously variable transmission that uses a rubber or resin V-belt, if oil or water adheres to the pulleys or V-belt, belt slip will occur, and as a result, the input rotation speed (engine The problem arises that the engine speed (rpm) increases. However, during shift control, the input rotation speed changes from moment to moment, so even if the input rotation speed temporarily increases, it is difficult to determine whether the cause is due to a hert slip or some other cause. It is difficult to do so, and there is a risk of misjudgment.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a vehicle that can reliably determine belt slip from changes in input rotational speed during shift control and quickly eliminate belt slip.
An object of the present invention is to provide a method for releasing a hert slip in a belt type continuously variable transmission.

Structure of the Invention In order to achieve the above object, the present invention provides a thrust loading device that loads the thrust necessary for torque transmission to one of the driving pulley or the driven pulley, and a hydraulic pressure device to control the gear ratio to the other. A chamber is provided, and control hydraulic pressure is guided to the hydraulic chamber from a hydraulic control device having a solenoid valve, and the hydraulic control device also controls a shift control duty including a target input rotation speed of the drive pulley determined according to the operating state. When the control range is set and the actual input rotation speed is outside the duty control range, the solenoid valve is continuously turned ON or OFF so that the actual input rotation speed falls within the duty control range. V that outputs a duty control signal to the solenoid valve according to the magnitude of the actual input rotation speed when it is within the control range.
In a belt-type continuously variable transmission, the duty control area for belt slip release is set at a location higher than the upper limit of the duty control area for speed change control, and the actual input rotation speed falls within the duty control area for releasing belt slip. At this time, a duty control signal is output to the solenoid valve in a direction in which the oil pressure in the oil pressure chamber increases.

In other words, when belt slip occurs during gear shift control, the input rotation speed increases, but belt slip occurs when the input rotation speed enters the belt slip release duty control range, which is higher than the upper limit of the shift control duty control range. At this time, a duty control signal is output to the solenoid valve to increase the thrust force in the hydraulic chamber and eliminate belt slip.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows an example of a V-belt type continuously variable transmission according to the present invention, in which a crankshaft 2 of an engine 1 is connected to an input shaft 4 via a damper mechanism 3. An external gear 5 is fixed to the end of the input shaft 4, and this external gear 5 meshes with an internal gear 6 fixed to the drive shaft 11 of the continuously variable transmission 10 to transfer the power of the input shaft 4. The speed is decelerated and transmitted to the drive shaft 11.

The continuously variable transmission 10 includes a drive pulley 1 provided on a drive shaft 11.
2, a driven side boot 4 provided on the driven shaft 13, and a V-belt 15 wound between both pulleys. The drive pulley 12 has a fixed sheave 12a and a movable sheave 12b.
A torque cam device 16, which is an example of a thrust loading device, and a compression spring 17 are provided behind the movable sheave 12b. The torque cam device 16 generates a thrust proportional to the input torque, and the compression spring 17
generates an initial thrust sufficient to prevent the V belt 15 from loosening, and these thrusts provide the V belt 15 with belt tension necessary for torque transmission. Note that the thrust load device is not limited to the torque cam device, but may also be a hydraulic servo device. On the other hand, similarly to the driving pulley X2, the driven pulley 14 has a fixed sheave 14a and a movable sheave 14b, and a hydraulic chamber 18 for speed ratio control is provided behind the movable sheave 14b. The hydraulic pressure to this hydraulic chamber I8 is controlled by a hydraulic control device 39, which will be described later.

A hollow shaft 19 is rotatably supported on the outer periphery of the driven shaft 13, and the driven shaft 13 and the hollow shaft 19 are connected and connected by a starting clutch 20 consisting of a wet multi-plate clutch. The hydraulic pressure applied to the starting clutch 20 is controlled by a hydraulic control device 39, which will be described later. A forward gear 21 and a reverse gear 22 are rotatably supported on the hollow shaft 19, and a forward/reverse switching dog clutch 23 connects either the forward gear 21 or the reverse gear 22 to the hollow shaft 19. It is designed to be connected. The l& advance idler shaft 24 has a reverse idler gear 25 that meshes with the reverse gear 22, and another 1 &
Advance idler gear 26 is fixed. Further, a counter gear 28 that meshes with the forward gear 21 and the reverse idler gear 26 at the same time, and a final reduction gear 29 are fixed to the counter shaft 27, and the final reduction gear 29 meshes with the ring gear 31 of the differential device 30. , transmits power to the output shaft 32.

The hydraulic control device 39 includes a pressure regulating valve 40 and a pulley control valve 43.
The pressure regulating valve 40 regulates the hydraulic pressure discharged from the oil reservoir 41 by the oil pump 42, and outputs it as line pressure to the pulley control valve 43 and the starting control valve. It is output to 45. The pulley control valve 43 and the start control valve 45 are operated by the solenoid 44.
46 to control the line pressure and output control hydraulic pressure to the hydraulic chamber 18 of the driven pulley 14 and the starting clutch 20, respectively.

The specific structure of the control valves 43 and 45 is a combination of a spool valve 50 and a solenoid valve 52 as shown in FIG.
As shown in the figure, a single three-bottom electromagnetic valve may be used, which selectively opens and closes an input boat 54 and a drain boat 55 using a ball-shaped valve body 53, and outputs control hydraulic pressure from an output boat 56.

For example, when the control valve 43, 45 is configured with a spool valve 50 and a solenoid valve 52 as shown in FIG. 2, and the duty ratio output from the electronic control device 60 to the solenoid valve 52 is D, The output oil pressure PIIIT of 50 is given by the following equation.

P, XA, =P,

In addition, when the control valve 43.45 is constituted by a single solenoid valve as shown in Fig. 3, its output oil pressure PlIIT is expressed by the following formula % formula % In formulas (1) and (2), A + + A2 , P
Since L and F are constant values, the duty ratio and the output oil pressure P are proportional, and the gear ratio of the continuously variable transmission 10 or the transmission torque capacity of the starting clutch 20 is variable depending on the output oil pressure P. In either case, the gear ratio of the continuously variable transmission 10 and the transmission torque capacity of the starting clutch 20 can be freely controlled by the duty ratio.

FIG. 4 shows a block diagram of the electronic control device 60, where 61 is a sensor that detects the engine rotation speed N:n (the rotation speed of the input shaft 4 may also be used), 62 is a sensor that detects the vehicle speed V, and 63
64 is a sensor for detecting the rotational speed NIIT of the driven shaft 13 (which may be the input rotational speed of the starting clutch 20 or the rotational speed of the driven side boot 4), and 64 are P, R, N, and D.

A sensor 65 detects each shift position of L, and 65 is a sensor that detects the throttle opening. Each signal from the sensors 61 to 64 is input to an input interface 66, and the signal from the throttle opening sensor 65 is input to an A/D converter. 67, it is converted into a digital signal. 68 is a central processing unit (CPU),
69 is a one-domain memory (ROM) in which programs and data for controlling the pulley control solenoid 44 and the start control solenoid 46 are stored, and 70 is a random access memory that temporarily stores signals and parameters sent from each sensor. Memory (RAM) 71 is an output interface, and these CPU 68, ROM 69, R
A M2O, the output interface 71, the input interface 66, and the A/D converter 67 are interconnected by a bus 72. The output of the output interface 71 is output as a duty control signal to the pulley control solenoid 44 and the start control solenoid 46 via the output driver buffer 3.

A method of controlling speed change vJ in the belt type continuously variable transmission having the above configuration will be explained.

(1) Target input rotation speed NE, which is the reference when executing initial setting speed change control
is set as shown in FIG. 5 in accordance with the operating state, for example, the throttle opening, and this setting data is stored in the ROM 69 of the electronic control unit 60. Note that the target input rotation speed NE may be set by considering factors such as vehicle speed and gear ratio in addition to the throttle opening.

When the target input rotation speed N is determined according to the throttle opening degree, the target input rotation speed N is set to 1α% (for example, 50%) of the duty ratio of the pulley control solenoid 44, as shown in FIG.
The duty control range for shift control is determined so as to correspond to χ). Then, when the actual input rotation speed N, n is greater than the upper limit value Nu of the duty control range, the pulley control solenoid 44 is continuously turned off (D=O%), and the actual input rotation speed N1n is less than the lower limit value NL. When the pulley control solenoid 44 is continuously turned on (CD=100%), and when the actual input rotation speed Nin is within the duty control range, the duty ratio increases from 100χ to 100% as the input rotation speed N1n increases. It is set to gradually decrease to 0%.

Duty ratio and input rotation speed N in shown in Figure 6
In addition to the duty control range for speed change control, the duty control range for belt slip release is also set in the setting data. That is, the duty control range for belt slip cancellation is the upper limit value N of the duty control range for shift control. higher OF
It is set in the F region, has a slope opposite to the duty control region for shift control, and is set so that the duty ratio gradually increases as the input rotational speed N1n increases. The lower limit value NX of the duty control range for belt slip release is set based on an input rotation speed that cannot be reached with Tsuho's shift control, so when the actual input rotation speed N1n is greater than the lower limit value Nx, the belt It can be determined that a slip has occurred. Note that the belt slip release duty control range is not limited to having an upward slope to the right as shown by the solid line in FIG. 6, but may be a stepped control range as shown by the broken line in FIG. In any case, immediately 0N (
By gradually increasing the oil pressure in the hydraulic chamber 18 without setting D=100χ), belt slip is gradually eliminated and a sudden shift toward a lower speed ratio is prevented.

(1 spirit) When the execution operation of the speed change control starts, the target input rotation speed N corresponding to the throttle opening at that time is read from Fig. 5, and the duty ratio is set to α% at this target input rotation speed NE. The duty control range for speed change control is determined as shown in Fig. 6, and the duty ratio corresponding to the actual input rotation speed N1n is read from Fig. 6. If the input rotation speed N in exceeds the upper limit value Nu, pulley control is performed. The solenoid 44 is turned off continuously.
(D-0%), and the daily oil pressure in the hydraulic chamber decreases, so the gear ratio of the continuously variable transmission 10 shifts to the high speed ratio side, and as a result, the input rotational speed increases as shown by the solid arrow in FIG. N in
is suppressed and returns to the duty control range for shift control.

On the other hand, if oil or water adheres to the bell [5] or the pulley, causing belt slip, the input rotation speed N, as shown by the broken line arrow in Figure 7. exceeds the duty control area for speed change control and enters the duty control area for belt slip release (N, n≧N
x), causing an increase in the input rotational speed that would not occur under normal speed change control.

In this case, the duty ratio corresponding to the input rotational speed N, n is read from the belt slip release duty control area shown in FIG. 6, and this duty ratio is output to the pulley control solenoid 44. As a result, the oil pressure in the hydraulic chamber 18 increases, and the pulley thrust of the driven pulley 14 increases, thereby canceling belt slip. When the belt slip is released, the input rotation speed N,. Abnormal racing is prevented, and the shift control returns to the duty control range.

Next, a specific example of the speed change control of the present invention will be explained according to the flowchart of FIG.

When the control starts, first, signals such as throttle opening θ and input rotation speed N1n are detected (80), and the target input rotation speed N corresponding to the detected slow/
The duty control range for shift control is determined so that this target input rotation speed Nε becomes the duty ratio α%, and the duty control range for shift control is set in the OFF region of the duty control range for shift control (81). A duty control area is determined (82).

Next, compare the actual input rotation speed N in with the lower limit value NL of the duty control range for shift control at that time83).
N ; When n < NL, pulley control solenoid 4
4 continuously (D=1002) (84),
As a result, the continuously variable transmission 10 is shifted to a lower speed ratio, and the input rotational speed N1n increases. In the case of N, naNL, input rotation speed N in and upper limit value N are input next. 85), if Nu≧N1n≧NL, read out the duty ratio corresponding to the input rotational speed N, n from the duty control area for shift control in Fig. 686), and set the duty ratio to the pulley. Output to control solenoid 44 (87)
-N, if n>N u, the input rotation speed N
, n and the lower limit value Nx of the duty control range for belt slip release.88), N. When ≦Nx, the pulley control solenoid 44 is continuously turned 0FF (D=0χ) (89), whereby the continuously variable transmission 10 is shifted to the high speed ratio side, and the input rotational speed N1n is reduced.

On the other hand, when N:n>Nx, the duty ratio corresponding to the input rotation speed N and Tl is read out from the belt slip release duty control area shown in FIG. Output (91)
.

In the above embodiment, a V-belt continuously variable transmission was shown in which a thrust loading device was provided on the driving pulley and a hydraulic chamber for speed ratio control was provided on the driven pulley. The pulley may be provided with a hydraulic chamber for speed ratio control, and the driven pulley may be provided with a thrust load device. However, in this case, the oil pressure in the hydraulic chamber is continuously ON (D= 1
00%), the lower limit value N, and below, the oil pressure in the hydraulic chamber becomes 0FF (D-0%) continuously, which is the opposite of the above embodiment.

Also, the relationship between duty ratio and oil pressure ON10 F F is reversed depending on whether the solenoid valve is normally open or normally closed, so for example, when the duty ratio is 0%, the oil pressure is ON, and when the duty ratio is 100%, the oil pressure is ON. It can also be set to OFF.

Effects of the Invention As is clear from the above explanation, according to the present invention, the duty control area for belt slip cancellation is set at a location higher than the upper limit of the duty control area for shift control, and the actual input rotation speed is set at a position higher than the upper limit of the duty control area for shift control. Since it is determined that belt slip has occurred when the release duty control area is entered, belt slip can be detected using only the software of the electronic control circuit, and no special sensor or device is required.

In addition, when the input rotation speed enters the belt slip release duty control range, a duty control signal is output to the solenoid valve to increase the thrust of the hydraulic chamber, making it possible to eliminate belt slip reliably and in a short time. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an example of a V-belt type continuously variable transmission to which the present invention is applied, FIGS. 2 and 3 are specific structural diagrams of a control valve,
Figure 4 is a block diagram of the electronic control unit, Figure 5 is a diagram showing setting data for target input rotation speed and throttle opening, and Figure 6 is a diagram showing setting data of the target input rotation speed and throttle opening.
The figure is a diagram showing setting data of the duty ratio and input rotation speed of the pulley control solenoid, Figure 7 is a shift diagram showing the duty control range, and Figure 8 is a flowchart showing an example of the belt slip cancellation method of the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1... Engine, 4... Input shaft, 10... Continuously variable transmission, 12... Driving side pulley, 14... Driven side pulley, 15... V belt, 16... Torque cam Device (thrust load device), 18... Hydraulic chamber, 20... Starting clutch, 32... Output shaft, 39... Hydraulic control device, 43... Pulley control valve, 44... Pulley control solenoid, 60...electronic control device. Fig. 1. 4. Leap slot wheel position - Support Fig. 6. Input rotation 1 (N,. Car running

Claims (1)

[Claims] A hydraulic control device in which one of the driving pulley or the driven pulley is provided with a thrust loading device that loads the thrust necessary for torque transmission, the other is provided with a hydraulic chamber for controlling the gear ratio, and the hydraulic chamber has a solenoid valve. In addition to guiding the control hydraulic pressure from At a certain time, the solenoid valve is continuously turned ON or OFF so that the actual input rotation speed falls within the duty control range, and when the actual input rotation speed is within the duty control range, the magnitude of the actual input rotation speed changes. In a V-belt continuously variable transmission that outputs a corresponding duty control signal to a solenoid valve, a duty control range for belt slip release is set at a location higher than the upper limit of the duty control range for speed change control, and the actual A belt for a V-belt type continuously variable transmission, characterized in that when the input rotation speed enters the belt slip release duty control range, a duty control signal is output to the solenoid valve in a direction in which the hydraulic pressure in the hydraulic chamber increases. How to release the slip.