JPS63170136A - Speed change control method for v belt driven continuously variable transmission - Google Patents

Abstract

PURPOSE:To continually obtain the ideal speed change characteristic, by correcting the whole duty control region, including a target input speed, in accordance with an amount of deviation, when it is generated between the actual input speed and the target input speed, and storing this correction result in memory executing a speed change control thereafter. CONSTITUTION:Pressure oil, supplied to and discharged from a pressure oil chamber 18 in a driven side pulley 14 and a starting clutch 20 performing interrupted connection between a driven shaft 13 and a hollow shaft 19, in a continuously variable transmission, is controlled by a pulley control valve 43 and a starting control valve 45 which are duty controlled, and each control valve 43, 45 is controlled by an electronic control unit 60. In a device such as in the above, when the actual input speed of a driving side pulley 12 is within a preset duty control region providing a deviation from the target input speed, set in accordance with an operative condition, in a fixed value or more, the electronic control unit 60 enables the duty control region to be corrected in a direction of decreasing said speed deviation. While a correction amount is stored in a memory means, and a speed change control thereafter is executed by using the correction amount stored in memory.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a speed change control method for a V-belt continuously variable transmission.

Prior Art and its Problems In a V-belt continuously variable transmission, the present applicant provided a thrust load bag device that loads the thrust necessary for torque transmission to one of the driving pulley or the driven pulley, and the other to the transmission ratio. A hydraulic chamber is provided for controlling the hydraulic pressure, and control hydraulic pressure is guided to the hydraulic chamber from a hydraulic control device having a solenoid valve. When 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-belt type stepless gearshift system that achieves 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. Proposed a method for controlling the speed change of a transmission (patent application 1986)
No. 1-173874! Iri.

In the case of the above speed change control method, the solenoid valve is duty controlled when the actual input rotation speed is within the duty control range,
The actual input rotation speed is controlled so as to gradually approach the input rotation speed when the thrust forces of both pulleys are balanced. That is,
The actual manual rotation speed approaches the balanced input rotation speed rather than the target input rotation speed. In particular, the balanced input rotational speed includes unstable factors such as variations in the return spring of the speed change control valve and fluctuations in line pressure, so the balanced input rotational speed and the target input rotational speed often differ. Variations occur in the speed change characteristics of the continuously variable transmission, and the transmission becomes unable to cope with deterioration over time.

Therefore, in order to bring the actual input rotation speed as close as possible to the target input rotation speed, it is necessary to correct the amount of deviation of the input rotation speed at the time of balancing with respect to the target input rotation speed. The method is to reduce the difference between the actual input rotation speed and the target input rotation speed when the actual input rotation speed is within the duty control range and the difference (deviation amount) from the target input rotation speed is greater than a certain value. It is conceivable to correct the shift of the duty control range in the direction. However, if the above-mentioned correction is performed every time the vehicle is driven, it is not possible to eliminate the above-mentioned deviation amount in a short time.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a V-belt continuously variable transmission that can complete the correction of the amount of deviation in a short time and always achieve ideal transmission characteristics. The objective is to provide a control method.

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 sets a duty control range including a target input rotation speed of the drive pulley determined according to the operating state. However, when 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 is within the duty control range, and the actual input rotation speed is within the duty control range. In a V-belt continuously variable transmission that outputs a duty control signal to a solenoid valve according to the magnitude of the actual input rotation speed, when the actual input rotation speed is within the duty control range and the target input If the difference between the actual input rotation speed and the target input rotation speed is greater than a certain value, the duty control area is corrected by moving in the direction that reduces the difference between the actual input rotation speed and the target input rotation speed. When the difference falls within a certain value, the correction is completed, the correction amount is stored in the storage means, and the stored correction amount is used to execute subsequent shift control.

In other words, since the result of correcting the amount of deviation between the actual input rotation speed and the target input rotation speed is stored in the storage means, the next time the same operating condition occurs, the correction can be made immediately using the contents of the memory. , the amount of misalignment can be eliminated in a short time. In addition, the contents of the storage means are sequentially updated to the optimum contents as the operating time passes, so it functions as a learning control function, absorbing product variations and deterioration over time, and making it possible to get closer to the ideal shifting characteristics. becomes.

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, so that the input shaft 4 receives power. is decelerated and transmitted to the drive shaft 11.

The continuously variable transmission 10 has a drive side gear 2 provided on a drive shaft 11.
And the driven side provided on the driven shaft 13 -? - is made up of a moon 4 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. In addition, as a thrust load device,
It is not limited to the torque cam device, but may also be a hydraulic servo device. On the other hand, the driven side pulley 14 also has a fixed sheave 14a and a movable sheave 14b, similar to the drive side booin2, and behind the movable sheave 14b is a gear ratio. A hydraulic chamber 18 for control is provided. The hydraulic pressure to this hydraulic chamber 18 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-disc 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 tongue clutch 23 for forward/reverse switching switches either the forward gear 21 or the reverse gear 22 to the hollow shaft 19. It is designed to be connected. A reverse idler gear 25 that meshes with the reverse gear 22 and another reverse idler gear 26 are fixed to the reverse idler shaft 24. Further, the counter shaft 27 is provided with the forward gear 21 and the reverse idler gear 2.
6 and a final reduction gear 29 are fixed, and the final reduction gear 29 meshes with a ring gear 31 of a differential device 30 and transmits power to an 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, it may be a single three-bottom solenoid valve that selectively opens and closes the input boat 54 and the drain boat 55 with the ball-shaped valve body 53 and outputs control hydraulic pressure from the 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 Pa1T of 50 is given by the following equation.

P, xA, = P, nxDxA2+F ・ftl In the above formula, A + and A 2 are each the spool valve 5
0, P in is the input oil pressure, and F is the spring load of the spring 51.

In addition, when the control valves 43, 45 are constituted by a single solenoid valve as shown in FIG. 3, the output oil pressure P. JT is the following formula % formula % [In formula 11, formula (2), A, , A2. P, n, F
Since is a constant value, the duty ratio and the output oil pressure P are proportional, and the output oil pressure pH is proportional to the continuously variable transmission. i! Since the transmission gear ratio of 10 or the transmission torque capacity of the starting clutch 20 is variable, in either case, the transmission 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 (or the rotation speed of the input shaft 4), 62 is a sensor that detects the vehicle speed, and 63 is the rotation speed of the driven shaft 13. A sensor for detecting the input rotation speed of the starting clutch 20 or the rotation speed of the driven side boot 4, 6
4 is a sensor that detects each shift position of P, R, N, D, L, 65 is a sensor that detects the throttle opening, each signal from the sensors 61 to 64 is input to the input interface 66, and the throttle opening is detected. The signal from the sensor 65 is converted into a digital signal by an A/D converter 67. 68 is a central processing unit (CPU), 69 is a pulley control solenoid 4
5 and the program and data for controlling the start control solenoid 47 are stored in the one-door only memory (RO
M), 70 is a random access memory (RAM) that temporarily stores signals and parameters sent from each sensor.
, 71 is a nonvolatile memory for storing correction results to be described later, and 72 is an output interface.
U68, ROM69, RAM70. Non-volatile RAM71
, the output interface 72, the input interface 66, and the A/D converter 67 are interconnected by a bus 73. The output of the output interface 72 is output as a duty control signal to the pulley control solenoid 44 and the start control solenoid 46 via the output driver buffer 4.

An overview of the speed change control method in the V-belt continuously variable transmission having the above configuration will be explained.

(i) Initial setting First, determine the target input rotation speed N corresponding to the throttle opening, and at that target input rotation speed N, the duty ratio is X%.
The duty-controlled tll area is determined so that The relationship data between the target input rotation speed NE and the throttle opening degree is stored in the ROM 69 of the electronic control unit 60, and for example, as shown in FIG. 5, the target input rotation speed NE gradually increases as the throttle opening degree increases. It is set. Note that the target input rotation speed NE is determined not only by the throttle opening degree, but also by taking into account factors such as vehicle speed and gear ratio. Related data is also stored in the ROM 69 of the electronic control unit 60, and as shown in FIG. 6, the target input rotation speed Nε is set so as to correspond to the duty ratio of the pulley control solenoid 44 of X%. Then, when the actual input rotation speed N1n is greater than the upper limit value N1 of the duty control range, the pulley control solenoid 44 is continuously turned off.
D=O%), and the actual input rotation speed N1o is the lower limit value NL.
In the following cases, the pulley control solenoid 44 is continuously turned on.
N (D=100%), and furthermore, the actual input rotation speed N
When in is within the duty control range, the duty ratio increases from 100χ to 0 as the input rotational speed N increases.
It is set to gradually decrease to %.

The duty ratio It is set to a constant value (50χ in the figure) regardless of the number NE). In this embodiment, only the relationship between the duty ratio X and the throttle opening θ is shown, but a factor of the gear ratio may be added to the throttle opening θ.

(11) Determine the target input rotation speed N corresponding to the throttle opening by the correction initial setting, determine the duty control range so that the duty ratio becomes X% at this target input rotation speed Nε, and set the actual input rotation speed Even if a duty ratio corresponding to the number N and n is output, a difference (deviation amount) as shown in Fig. 8 may occur between the actual manual rotation speed N in and the target input rotation speed N. . In order to correct this amount of deviation, the present invention moves the duty control area according to the position of the actual input rotation speed N in as shown in FIG.
If in is lower than the target input rotation speed N as shown in FIG. 8, the entire duty control range is moved upward as shown in FIG. 9, and the duty ratio corresponding to the target input rotation speed N is adjusted. is corrected from X% to X+7%. Thereby, the actual input rotational speed N, n can be made to substantially match the target input rotational speed N5. In addition, in FIG. 9, a method was explained in which the duty ratio corresponding to the target input rotation speed N is corrected from X% to X+7% in order to move the duty control range. The rotational speed of the corresponding duty ratio X% may be corrected from N to Nε° as shown in FIG. In this case as well, the correction results are the same.

(iii) Learning control As mentioned above, the duty ratio The correction is completed when the difference from the target input rotation speed NE falls within a certain value, and the initial memory stored in the nonvolatile memory 71 is rewritten with the correction result at the time of completion of the correction. The broken line in FIG. 7 shows the corrected data obtained by rewriting the initial memory in the entire throttle opening range. Thereafter, when the same operating conditions are reached, the duty control area can be moved to the desired position in a short time by making corrections using the data rewritten in the nonvolatile memory 71.

Next, a specific example of the speed change control of the present invention will be explained according to the flowchart of FIG. 1O.

When the control starts, the throttle opening θ and the actual input rotation speed N In are detected respectively.80), (81
), the target input rotation speed N corresponding to the detected throttle opening θ is determined from FIG. 5 (82), and the initial target rotation duty ratio X% corresponding to the throttle opening θ is stored in a non-volatile memory. 71 memory data (Fig. 7), and the target input rotation speed N is the duty ratio
% is determined from FIG. 6 (83). Note that the target rotational duty ratio X read from the nonvolatile memory 71 may be corrected data, but if it is the first cycle after the operating condition has changed, it is called initial data.

Next, compare the input rotation speed N in and the lower limit value NL.
4) If N in≦NL, the pulley control solenoid 44 is continuously turned on (D
= 100χ) (85). On the other hand, if N, n>NL, then compare the input rotation speed with the upper limit value Nu86),
If N in ≧ N, J, the pulley control solenoid 44 is continuously turned 0FF (D=0
%) (87).

When NU > N, n > NL, compare the absolute value of the difference between the target input rotation speed NEO one cycle ago and the current target input rotation speed NL with a constant value A88), and check the operating conditions, especially the throttle opening. Determine whether there is a change in degree.

If INF. -N[l≧A, it means that the driving situation is fluctuating drastically, so the duty ratio after correction X° and the duty ratio before correction should be defined as being equal89) Then, the control shifts to (100).

On the other hand, lNt. - If Nil<A, then compare the absolute value of the difference between the target input rotation speed N and the actual input rotation speed N, n with a constant value B (90) for the target input rotation speed N. It is determined whether the actual input rotational speed N1n deviates by a certain value or more. If IME-N,n+≦B, it means that the input rotation speed Nin is already close to the target input rotation speed N, so the corrected target input rotation speed
It is defined as (91).

In other words, if the amount of deviation between the actual input rotation speed N in and the target input rotation speed N becomes equal to or less than the fixed value B, there is no need for correction, so the correction control is completed, and the duty ratio X after correction is
The data in the non-volatile memory 71 is rewritten by °% and the control shifts to (92) and (100).

If 1 N, -Nirll > B, then determine the magnitude relationship between the target input rotation speed N and the actual input rotation speed N in (93), and if NL>N, proceed to (94),
If NE≦N1n, proceed to (97). In (94), the time rate of change of the actual input rotation speed N1o is compared with the constant value C, and when dNtn/dt<C, the input rotation speed N1n is the target input rotation speed. Since this is a case where the duty ratio is gradually increasing toward N, the duty ratio
Since n is rapidly increasing toward the target input rotation speed NE, the duty ratio Therefore, its absolute value is compared with the constant value C, and when l d N:n/ d t l < C, the input rotation speed N in is gradually decreasing toward the target input rotation speed N. In this case, the duty ratio Therefore, the duty ratio
is added by ΔX (99).

After correcting the duty ratio X' as described above, the duty ratio corresponding to the actual input rotation speed N is determined and outputted so that the target input rotation speed N becomes the duty ratio X'% (100), and henceforth. Repeat this action. The above control (
The processing time for one cycle of 80) to (100) is T (s
ec) Then, since the correction amount per cycle is ΔX, the correction amount per unit time is ΔX/T, and T, ΔX
are both constant values, so the correction amount per unit time Δx/
T also becomes a constant value. Since the correction amount Δx/T per unit time is limited to a constant value as described above, the input rotation speed N is the target input rotation speed N for n when correction is performed all at once in a short period of time.

It is possible to prevent the input rotation speed N1n from exceeding the target input rotation speed NE in a smooth and reliable manner.

In the above embodiment, a nonvolatile memory was used as a storage means, but a normal rewritable memory can be used instead. However, since the contents of the nonvolatile memory will not be erased by turning off the power, the operation should be stopped once. The memory content is also preserved, allowing for higher-performance learning control functions.

Further, 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 loading device. However, in this case, the oil pressure in the hydraulic chamber is continuously ON above the upper limit Nu (D = 1).
00%), and below the lower limit NL, the oil pressure in the hydraulic chamber becomes 0FF (D, = 0%) continuously, which is the opposite of the above embodiment.

Furthermore, the relationship between duty ratio and oil pressure 0N10FF 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 OFF. It can also be set as follows.

Effects of the Invention As is clear from the above explanation, according to the present invention, when there is a discrepancy between the actual input rotation speed and the target input rotation speed, the entire duty control range including the target input rotation speed is adjusted to the amount of deviation. In addition to making corrections accordingly, the correction results are stored in the storage means, so the next time a similar operating condition occurs, the correction data can be used to correct the actual input rotation speed in a short time. The rotation speed can be brought closer to the input rotation speed. Furthermore, as the operation time passes, the contents of the storage means are automatically updated to the transmission characteristics that are most suitable for the transmission, so it is possible to account for product variations and aging deterioration of the transmission.

[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 applicable, and FIGS. 2 and 3 are specific structural diagrams of a control valve.
Figure 4 is a block diagram of the electronic control device, Figure 5 is a diagram showing the relationship between target input rotation speed and throttle opening, and Figure 6 is a diagram showing the relationship between the duty ratio of the pulley control solenoid and input rotation speed. FIG. 7 is a diagram showing the relationship between the duty ratio and the throttle opening degree corresponding to the target input rotation speed, and FIG. 8 is a diagram. FIG. 9 is a shift diagram showing the relationship between the duty control range before and after correction and the actual input rotation speed, and FIG. 1θ is a flowchart showing an example of the shift control method of the present invention. DESCRIPTION OF SYMBOLS 1... Engine, 4... Input shaft, 10... Continuously variable transmission, 12... Driving side pulley, 14... Driven side pulley, 15... ■ 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 60...Electronic control unit, 71...Nonvolatile memory (storage means). Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Throat +1-(1)* Fig. 6 Fig. 7 Throttle relation Fig. 9 Car ton

Claims (3)

[Claims] (1) A thrust loading device that loads the thrust necessary for torque transmission is provided on one of the driving pulley or the driven pulley, a hydraulic chamber for controlling the gear ratio is provided on the other, and a solenoid valve is provided in the hydraulic chamber. In addition to guiding the control hydraulic pressure from the hydraulic control device,
The hydraulic control device sets a duty control range that includes the target input rotation speed of the driving pulley, which is determined according to the operating condition, and when the actual input rotation speed is outside the duty control range, the actual input rotation speed is set within the duty control range. Continuously turn the solenoid valve ON or OFF so that it falls within the control range, and when the actual input rotation speed is within the duty control range, output a duty control signal to the solenoid valve according to the magnitude of the actual input rotation speed. In a V-belt continuously variable transmission, if the actual input rotation speed is within the duty control range and the difference between the target input rotation speed and the target input rotation speed is a certain value or more, the actual input rotation speed and the target input rotation speed are The duty control range is corrected by moving in a direction that reduces the difference between the actual input rotation speed and the target input rotation speed, and the correction is completed when the difference between the actual input rotation speed and the target input rotation speed is within a certain value, and the correction amount is stored in the storage means. A shift control method for a V-belt type continuously variable transmission, characterized in that the stored correction amount is used to perform subsequent shift control. (2) A speed change control method for a V-belt type continuously variable transmission according to claim 1, wherein the storage means is a nonvolatile memory. (3) The V-belt type continuously variable transmission according to claim 1 or 2, wherein the amount of correction per unit time when performing movement correction in the duty control range is a constant amount. Shift control method.