JP2857783B2 - Shift control method for continuously variable transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a shift control method for a continuously variable transmission, and in particular, avoids a reduction in followability of a target engine speed due to an abnormal integrated value. The present invention relates to a shift control method for a continuously variable transmission, which can prevent a shift delay due to prohibition of a simple integration process.

[Conventional technology]

In a vehicle, a transmission is interposed between an internal combustion engine and drive wheels. With this transmission, the driving force of the drive wheels and the traveling speed are changed in accordance with the traveling conditions of the vehicle that vary widely, and the performance of the internal combustion engine is sufficiently exhibited.

The transmission is formed between both pulley parts of a pulley having, for example, a fixed pulley part fixed to a rotating shaft and a movable pulley part attached to the rotating shaft so as to be able to approach and separate from the fixed pulley part. There is a continuously variable transmission that transmits and receives power by increasing / decreasing the radius of rotation of a belt wound around both pulleys by increasing / decreasing a groove width of the belt and changing gear ratio (belt ratio).

As this continuously variable transmission, for example, Japanese Unexamined Patent Publication No.
There is one disclosed in Japanese Patent Publication No. The one disclosed in this publication is based on a first signal based on detection signals of a throttle opening and a vehicle speed.
-The optimum target engine speed is determined from the second target engine speed and the like, and the shift control is performed according to the optimum target engine speed, so that the driving characteristics required by the driver can be easily exhibited. is there.

[Problems to be solved by the invention]

By the way, in the conventional shift control method, an error between the target engine speed and the actual engine speed is subjected to a proportional process and an integral process, and the shift control is performed so as to change a ratio as a speed ratio. The ratio line, which is the speed ratio limit value of the shift control, is determined as an overdrive line or a full low line depending on the mechanical dimensions of the components of the continuously variable transmission, and the intermediate speed between the overdrive line and the full low line. The shift control is performed in an intermediate ratio region that is a ratio region.

However, when the actual ratio shifts to the vicinity of the ratio line of the overdrive line or the full-low line and the actual engine speed is located on the ratio line, the target engine speed is set to the full-low line with the overdrive line. It may be located outside the intermediate ratio area defined by the line and outside.

In such a case, an error between the target engine speed and the actual engine speed always occurs, so that accumulation of the integral value is continued. As a result, the integral value becomes an abnormal value, causing a problem in the shift control. For example, the actual engine speed cannot follow the change in the target engine speed,
There was a problem that the followability was reduced.

Further, in order to eliminate such inconvenience, when the ratio value shifts to the vicinity of the ratio line, by inhibiting the integration process, accumulation of the integral value is prevented, and the integral value becomes an abnormal value. It is possible to prevent it. But,
If the shift control is performed by simply prohibiting the integration process using only the ratio value, when shifting to the intermediate ratio region side, the necessary integration process is not performed and only the proportional process is performed. there were.

[Object of the invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a continuously variable transmission capable of avoiding a reduction in followability of a target engine speed due to an abnormal integrated value and capable of avoiding a shift delay caused by prohibiting a simple integration process. To realize the speed change control method.

[Means for solving the problem]

In order to achieve this object, the present invention increases the groove width between both pulley parts of a pulley having a fixed pulley part and a movable pulley part detachably attached to the fixed pulley part. In a speed change control method for a continuously variable transmission that performs speed change control to change a speed ratio by increasing or decreasing a rotation radius of a belt wound around both pulleys, a speed ratio determined by a mechanical size of components of the continuously variable transmission, and the like. An intermediate speed ratio region is set between the overdrive line and the full low line, which are the limit values, and the speed control is performed so as to change the speed ratio by proportionally and integrating the error between the target engine speed and the actual engine speed. Control means for setting an overdrive-side trigger value line on the intermediate speed ratio area side of the overdrive line, and A full low side trigger value line is set on the side of the intermediate speed ratio range, and the control means causes the actual speed ratio of the continuously variable transmission to exceed the overdrive side trigger value line and the full low side trigger value line, thereby setting the speed ratio limit value. In the case of shifting to the vicinity of the overdrive line and the full low line, the integration process is prohibited and the shift control is performed so as to change the gear ratio, and the overdrive trigger value line and the full low trigger value line are exceeded. In the case where the actual speed ratio shifted to the vicinity of the overdrive line and the full low line, which are the speed ratio limit values, is shifted to the intermediate speed ratio region side, speed control is performed so as to allow the integration process and change the speed ratio. It is characterized by.

[Action]

According to the configuration of the present invention, the intermediate speed ratio region is set between the overdrive line and the full low line, which are the speed ratio limit values determined by the mechanical dimensions of the components of the continuously variable transmission, and the target engine speed is set. Control means for performing a speed change control so as to change a speed ratio by performing a proportional process and an integral process on an error between the engine speed and the actual engine speed, and this control means causes an overdrive side trigger to be provided in the intermediate speed ratio region side of the overdrive line. A value line is set and a full low side trigger value line is set on the intermediate speed ratio area side of the full low line. By this control means, the actual speed ratio of the continuously variable transmission is set to the overdrive side trigger value line and the full low side. When shifting over the trigger value line to the vicinity of the overdrive line and the full low line which are the gear ratio limit values, Shift control is performed to inhibit the integration process and change the gear ratio, and shifts to the vicinity of the overdrive line and the full low line, which are the gear ratio limit values, beyond the overdrive side trigger value line and the full low side trigger value line. When shifting the actual speed ratio to the intermediate speed ratio region side, the integration process is allowed and the speed control is performed so as to change the speed ratio, whereby the integrated value is accumulated and becomes an abnormal value. Can be prevented, and not only proportional processing but also necessary integral processing can be performed.

〔Example〕

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

1 to 5 show an embodiment of the present invention.
In FIG. 5, reference numeral 2 denotes a belt-driven continuously variable transmission,
4 is a belt, 6 is a driving pulley, 8 is a driving fixed pulley piece, 10 is a driving movable pulley piece, 12 is a driven pulley, 14 is a driven fixed pulley piece, and 16 is a driven pulley. It is a movable pulley piece.

The drive-side pulley 6 includes a drive-side fixed pulley piece 8 fixed to the input shaft 18 serving as a rotation shaft, and a drive-side pulley 6 mounted on the input shaft 18 so as to be movable in the axial direction of the input shaft 18 and non-rotatably. And a movable pulley piece 10. The driven pulley 12 has an output shaft 20 serving as a rotating shaft, a driven fixed pulley piece 14, and a driven movable pulley piece 16, like the driven pulley 6.

First and second housings 22 and 24 are mounted on the driving-side movable pulley portion 10 and the driven-side movable pulley portion 16 respectively, and first and second hydraulic chambers 26 and 28 are formed, respectively. . In the second hydraulic chamber 28 on the driven side, there is provided a biasing means 30 including a spring or the like for biasing the second housing 24 in the direction in which the second hydraulic chamber 28 expands.

The input shaft 18 is provided with an oil pump 32. The oil pump 32 sucks oil from an oil pan 34 through an oil filter 36, and supplies the oil to the first and second hydraulic chambers 26 and 28 through first and second oil passages 38 and 40, respectively. Is what you do.

In the middle of the first oil passage 38, a primary pressure control valve 42 as a shift control valve for controlling a primary pressure as an input shaft sheave pressure is opened. A third oil passage is provided in the second oil passage 40 closer to the oil pump 32 than the primary pressure control valve 42.
The line pressure (generally 5 to 25 kg / cm ² ) is maintained at a constant pressure (3
定 4 kg / cm ² ), and a first three-way solenoid valve 50 for the primary pressure control valve is connected to the primary pressure control valve 42 via a fourth oil passage 48.

In the middle of the second oil passage 40, a line pressure control valve 52 having a relief valve function for controlling a line pressure serving as a pump pressure is connected through a fifth oil passage 54, and the line pressure control valve 52 is connected to the sixth line. A second line pressure control valve for the oil passage 56
The three-way solenoid valve 58 is connected.

Further, a clutch pressure control valve 60 for controlling clutch pressure is communicated with a seventh oil passage 62 in the second oil passage 40 closer to the second hydraulic chamber 28 than a portion where the line pressure control valve 52 communicates. The clutch oil pressure control valve 60 has an eighth oil passage.
A third three-way solenoid valve 66 for the clutch pressure control valve is communicated by 64.

The constant pressure control valve 46 includes a primary pressure control valve 42 and a first three-way solenoid valve 50, a line pressure control valve 52 and a second three-way solenoid valve 58, and a clutch pressure control valve 60 and a third three-way solenoid valve.
The ninth oil passage 68 communicates with each other.

The clutch pressure control valve 60 communicates with the clutch hydraulic chamber 72 of the hydraulic clutch 70 through a tenth oil passage 74, and communicates a pressure sensor 78 in the middle of the tenth oil passage 74 with an eleventh oil passage 76. This pressure sensor 78
The hydraulic pressure can be directly detected when controlling the clutch pressure in the hold mode, the start mode, and the like, which contributes to instructing the detected hydraulic pressure to be the target clutch pressure.
In the drive mode, the clutch pressure becomes equal to the line pressure, which also contributes to the line pressure control.

In the tenth oil passage 74 between the clutch pressure control valve 60 and the eleventh oil passage 76, a manual shift valve 80 and a shift servo valve 82 are sequentially provided from the clutch pressure control valve 60 side. The manual shift valve 80 communicates with the second oil passage 40 via a twelfth oil passage 84.

An input shaft rotation detection gear 86 is provided outside the first housing 22 of the drive side pulley 6.
A first rotation detector 88 on the input shaft side is provided in the vicinity of the outer peripheral portion of. An output shaft rotation detection gear 90 is provided outside the driven housing pulley 12 outside the second housing 24, and a second rotation detector on the output shaft side is provided near an outer peripheral portion of the output shaft rotation detection gear 90.
92 will be provided. Then, the detection signals from the first rotation detector 88 and the second rotation detector 92 are transmitted to the control unit 11 as control means described later.
It is input to 0 to grasp the engine speed and the belt ratio.

The hydraulic clutch 70 includes a clutch hydraulic chamber 72, a piston 94, an annular spring 96, a first pressure plate 98,
A friction plate 100, a second pressure plate 102,
It is composed of A final output shaft 104 is connected to the friction plate 100 of the hydraulic clutch 70. An output transmission gear 106 is provided on the final output shaft 104, and a third rotation detector 108 for detecting rotation of the final output shaft 104 is provided near an outer peripheral portion of the gear 106. This third rotation detector 108
Is for detecting the rotation of a reduction gear (not shown) and a final output shaft 104 directly connected to a differential, a drive shaft, and a tire, and the gear can be detected. Further, the hydraulic clutch 70 is provided by the second rotation detector 92 and the third rotation detector 108.
Can be detected before and after input / output, which contributes to the detection of the clutch slip amount.

A control unit 110 is provided for inputting various conditions such as the engine speed and vehicle speed from these first to third rotation detectors 88, 92 and 108, and the carburetor throttle opening of the vehicle (not shown). The opening / closing operation of the first three-way solenoid valve 50, the second three-way solenoid valve 58, and the third three-way solenoid valve 66 is controlled to perform a shift control.

The various signals input to the control unit 110 and the functions of the signals will be described in detail. The following signals are required for each range by the range signal of P, R, N, D, L, etc. Line pressure, ratio, clutch control, carburetor throttle opening detection signal …… Detects engine torque from memory previously input into the program, determines target ratio or target engine speed, carburetor idle position detection signal Accuracy improvement in correction and control of the carburetor throttle opening sensor, accelerator pedal signal …… Detects the driver's will based on the depression of the accelerator pedal, determines the control direction when driving or starting, brake signal …… Brake pedal Detects the presence or absence of the stepping action of the motor, determines the control direction such as disengagement of the clutch, etc. De option signal ...... performance sports of the vehicle (or the economy of)
There is an option to use it.

In the continuously variable transmission 2, the oil pump 32 located on the input shaft 18 operates according to the rotation of the input shaft 18, and the oil pan 34
Is sucked through the oil filter 36. The line pressure, which is the pump pressure, is controlled by the line pressure control valve 52.If the amount of leakage from the line pressure control valve 52, that is, the escape amount of the line pressure control valve 52, is large, the line pressure becomes low.
Conversely, if the amount is small, the line pressure increases.

The operation of the line pressure control valve 52 is controlled by a dedicated second three-way solenoid valve 58, and the line pressure control valve 52 operates following the operation of the second three-way solenoid valve 58. The second three-way solenoid valve 58 is controlled at a constant frequency duty ratio.
That is, when the duty ratio is 0%, the second three-way solenoid valve 58 does not operate at all, the output side is connected to the atmosphere side, and the output oil pressure is zero. When the duty ratio is 100%, the second three-way solenoid valve 58 operates, the output side is connected to the input side, and the maximum output oil pressure is equal to the control pressure. That is, the second three-way solenoid valve 58 changes the output oil pressure by changing the duty ratio. Therefore, the characteristics of the second three-way solenoid valve 58 enable the line pressure control valve 52 to operate in an analog manner, and control the line pressure by arbitrarily changing the duty ratio of the second three-way solenoid valve 58. be able to. The operation of the second three-way solenoid valve 58 is controlled by the control unit 110.

The primary pressure for shifting control is the primary pressure control valve 42
The operation of the primary pressure control valve 42 is controlled by a dedicated first three-way solenoid valve 50, similarly to the line pressure control valve 52. This first three-way solenoid valve 50
Used to conduct the primary pressure to the line pressure or to conduct the primary pressure to the atmosphere side, and to conduct the line pressure to shift the gear ratio to the full overdrive side, or to communicate to the atmosphere side to shift to the full low side Things.

The clutch pressure control valve 60 for controlling the clutch pressure is connected to the line pressure side when the maximum clutch pressure is required, and is connected to the atmosphere side when the minimum clutch pressure is required. This clutch pressure control valve 60 is
Like the 52 and the primary pressure control valve 42, the operation is controlled by the dedicated third three-way electromagnetic piece 66, and the description is omitted here. The clutch pressure varies within a range from a minimum atmospheric pressure (zero) to a maximum line pressure.
The control of the clutch pressure is changed according to the above-described pattern.

Further, the primary pressure control valve 42 and the line pressure control valve 5
2. The clutch pressure control valve 60 is controlled by output hydraulic pressures from the first, second and third three-way solenoid valves 50, 58 and 66, respectively, and these first, second and third three-way solenoid valves are controlled. 50, 5
The control oil pressure for controlling 8, 66 is a constant oil pressure adjusted by the constant pressure control valve 46. This control oil pressure
The pressure is always lower than the line pressure, but is stable and constant. The control oil pressure is controlled by each control valve 42, 52,
The control valves 42, 52, and 60 are also used to stabilize the control valves.

In this manner, the continuously variable transmission 2 is hydraulically controlled by a command from the control unit 110, and controls an appropriate line pressure for belt holding and torque transmission, a primary pressure for changing the gear ratio, and the hydraulic clutch 70. The clutch pressure for ensuring the engagement is ensured, and the speed is controlled so as to increase or decrease the radius of rotation of the belt 4 wound around the pulleys 6 and 12 to change the speed ratio.

In such a speed change control method for the continuously variable transmission 2, the intermediate speed ratio region is defined between the overdrive line and the full line, which are the speed ratio limit values determined by the mechanical dimensions of the components of the continuously variable transmission 2. The control unit 110 is configured to perform a shift process to change a gear ratio by performing a proportional process and an integral process on an error between a target engine speed and an actual engine speed calculated from a throttle opening and a vehicle speed. The control unit 110 sets an overdrive-side trigger value line on the intermediate speed ratio area side of the overdrive line and sets a full-low trigger value line on the intermediate speed ratio area side of the full-low line,
The control unit 110 shifts the actual speed ratio of the continuously variable transmission 2 to the vicinity of the overdrive line and the full low line, which are the speed ratio limit values, beyond the overdrive side trigger value line and the full low side trigger value line. In this case, the integration process is prohibited and the speed control is performed so as to change the speed ratio, and the overdrive line and the full low line which are beyond the overdrive side trigger value line and the full low side trigger value line and are the speed ratio limit values. In the case where the actual speed ratio shifted to the vicinity of the range is shifted to the intermediate speed ratio region side, the speed control is performed so as to allow the integration process and change the speed ratio.

Specifically, as shown in FIG. 2, an error E0 is calculated from the target engine speed NESPR calculated from the throttle opening and the vehicle speed and the actual engine speed NE which is the actual engine speed.
R is calculated. This error E0R is subjected to a proportional process, and a first error E1R is calculated by a proportional gain KBR (200).

The first error E1R is switched by the switching unit (202) to an integral gain (204) D1iR and an integral Z ^-1 (206) for performing an integration process. The integration process is for calculating the integrated value X1iR, and is performed by integrating the first error E1R with the integral gain (204).
^-1 (206) is updated to obtain an integral value X1iR.

Next, the second error E2R is calculated from the first error E1R and the integrated value X1iR.
Is calculated and the second error E is calculated from the ratio solenoidal value NNOMR.
2R is reduced, and the shift control of the continuously variable transmission 2 is performed by the ratio solenoid duty OPWRAT.

 The integration process is represented by X1iR = (previous X1iR) + {E1R * D1iR} (where E1R = (NESPR-NE) * KBR).

Inhibiting this integration process means that the actual ratio RATC and the first
When the error E1R satisfies either condition of {(RATC <0.6) · (E1R <0)} or {(RATC> 2.04) · (E1R> 0)}, the switching unit (202) sets the YES side. , The addition of {E1R * D1iR} in the above equation is not performed.

That is, as shown in FIG. 3, the ratio line as the speed ratio limit value in the shift control is determined as the overdrive line P or the full low line Q depending on the mechanical dimensions of the components of the continuously variable transmission, and the like. Shift control is performed in an intermediate ratio region R, which is an intermediate speed ratio region between P and the full low line Q. When the actual ratio as the actual gear ratio shifts to the vicinity of the overdrive line P and the full low line Q in the intermediate ratio region R defined by the overdrive line P and the full low line Q, as described above, the integral value X1iR Becomes an abnormal value, or a problem when the integration process is simply prohibited.

Therefore, the overdrive line P in the intermediate ratio region R
And when the actual ratio RATC shifts to the vicinity of the full low line Q, the switching unit (202) switches to the YES side to inhibit the integration process and control the speed change so as to change the speed ratio. When shifting the actual ratio RATC near the line P and the full low line Q to the intermediate ratio region R, the switching unit (202) is switched to the NO side to allow the integration process and change the gear ratio. By performing shift control as much as possible, it is possible to prevent the integral value X1iR from being accumulated unnecessarily and become an abnormal value, and to perform not only proportional processing but also necessary integral processing.

In this embodiment, the trigger value of the actual ratio RATC for judging that the actual ratio RATC has shifted to the vicinity of the overdrive line P and the full low line Q is set to be higher than that of the overdrive line P and the full low line Q. It is set on the intermediate ratio area R side. This is because there are differences in the values of the overdrive line P and the full low line Q, detection errors occur in the low rotation speed range due to the performance of the detection unit that detects the vehicle speed, and errors occur when calculating the vehicle speed signal and the ratio value. And the ratio change near the overdrive line P and the full low line Q is caused by the intermediate ratio region R
The actual ratio RATC = 0.0 in the intermediate ratio region R side of the overdrive line P due to the reason that the integration process is performed more than necessary because the change is slower than the change in.
6, the overdrive side trigger value line P 'is set on the intermediate ratio region R side of the full low line Q, and the full low side trigger value line Q' of the actual ratio RATC = 2.04 is set.

The actual ratio is set near the overdrive line P and the full low line Q beyond the overdrive side trigger value line P 'and the full low side trigger value line set in this way.
When the RATC shifts, that is, the actual ratio RATC becomes RATC <
In the case of 0.6 or RATC> 2.04, the integration process is prohibited, and even if the actual ratio RATC is RATC <0.6, control is performed toward the intermediate ratio region R (E1R ≧ 0), or the actual ratio RATC is R
Even when ATC> 2.04, when control is performed toward the intermediate ratio region R (E1R ≦ 0), integration processing is permitted.

Next, the shift control of the continuously variable transmission 2 will be described with reference to the flowchart of FIG.

When the shift control program of the continuously variable transmission 2 is started by driving the internal combustion engine (not shown) (300), it is determined whether the operating state is the drive mode DRV (302).

If the determination (302) is YES, the target engine speed NESPR is calculated (304), and the target engine speed NESPR is calculated.
The actual engine speed NE is subtracted from NESPR to obtain the error E0R (30
6) is calculated, and the error E0R is proportionally processed to obtain a proportional gain KB.
A first error E1R is obtained from R (308).

Then, if the actual ratio RATC is RATC <0.6 or RATC ≧ 0.6
Is determined (310). If RATC <0.6, first
It is determined whether the error E1R is E1R <0 or E1R ≧ 0 (312). If E1R <0, the first error E and the integrated value X1iR in which {E1R * D1iR} is not added to the previous integrated value X1iR
The second error E2R is calculated from 1R (314), the ratio error duty OPWRAT is calculated by subtracting the second error E2R from the ratio solenoidal value NNOMR (316), and the program is returned (318).

In the judgment (310), the actual ratio RATC is RATC ≧ 0.6.
In this case, it is determined whether RATC> 2.04 or RATC ≦ 2.04 (320). If RATC> 2.04, the first error E1R
Is determined whether E1R> 0 or E1R ≦ 0 (32
2). If E1R> 0, ｛E1R is added to the previous integral value X1iR.
* A second error E2R is calculated from the integrated value X1iR not adding D1iR1 and the first error E1R (314), and the ratio error solenoid duty OPWRAT is calculated by subtracting the second error E2R from the ratio solenoidal value NNOMR (314). 316), and return (318) the program.

In the determination (320), the actual ratio RATC is RATC ≦ 2.0.
If it is 4, the integral value X1iR is calculated by adding {E1R * D1iR} to the previous integral value X1iR (324), and the integral value X1iR is calculated.
A second error E2R is calculated from R and the first error E1R (314), and a ratio solenoid duty OPWRAT is calculated by subtracting the second error E2R from the ratio solenoidal value NNOMR (316), and the program is returned (318). .

Also, even if RATC <0.6 in the judgment (310), if E1R ≧ 0 in the judgment (312), or if the judgment (32)
Even if RATC> 2.04 in 0), judgment (322)
When E1R ≦ 0, the previous integral value X1iR is added to {E1R * D1iR}
Is calculated to calculate an integral value X1iR (324), and a second error E2R is calculated from the integral value X1iR and the first error E1R (31).
4) Then, the second error E2R from the ratio solenoid value NNOMR
Is subtracted to calculate the ratio solenoid duty OPWRAT (316), and the program is returned (318).

If the determination (302) is NO, another ratio control is performed (326), and the process returns (318).

As described above, when the actual ratio RATC moves to the vicinity of the overdrive line P and the full low line Q beyond the overdrive side trigger value line P 'and the full low side trigger value line Q', the integration process is prohibited and the shift is performed. The gear ratio control is performed so as to change the ratio, and the actual ratio RATC that has moved to the vicinity of the overdrive line P and the full low line Q beyond the overdrive side trigger value line P ′ and the full low side trigger value line Q ′ is set to the intermediate value. In the case of shifting to the ratio region R side, by performing the shift control so as to allow the integration process to change the gear ratio, it is possible to prevent the integral value X1iR from being accumulated unnecessarily and become an abnormal value. Necessary integration processing as well as proportional processing can be performed.

For this reason, it is possible to eliminate the adverse effect on the shift control due to the abnormal integrated value, thereby avoiding a reduction in the followability of the target engine speed, and to prevent the occurrence of a shift delay due to the prohibition of the simple integration process. Can be avoided.

The shift control of the continuously variable transmission 2 will be described in more detail with reference to FIGS.

In FIG. 3 (NCO-NE characteristic), consider a case where the target engine speed NESPR changes from <a> to <b> to <c>.

When the target engine speed NESPR changes from <a> to <b> and the conventional "C: no integration processing is prohibited", the actual engine speed NE reaches the overdrive line P (<d
> State), the integration process is performed even though the first error E1R cannot be reduced. Therefore, the fourth
As shown in the figure, there is a disadvantage that the integral value is only decreasing and becomes an abnormal value.

In addition, the conventional simple "B: (RATC <0.6) or (RAT
In the case of “C> 2.04), the integration process is prohibited because the actual ratio RATC becomes RATC <0.6 at the point <g> in the case of“ integration processing is prohibited in the case of C> 2.04). Therefore, the integrated value does not become abnormal. The control in this case is performed according to “A: (RATC <0.6) · (E1R
<0) or (RATC> 2.04) · (E1R> 0), the integration process is prohibited ”, and the integrated value does not become abnormal.

However, the target engine speed NESPR changes from <b> → <c
>, The conventional "C: no integration processing prohibited" requires that the abnormal integrated value be returned to a normal value.

In addition, the conventional simple "B: (RATC <0.6) or (RAT
In the case of “C> 2.04), the integral processing is prohibited”, because only the proportional component is controlled by the proportional processing up to the point <h>, it is difficult to make the actual engine speed NE coincide with the target engine speed NESPR. At the point <h>, the actual ratio RATC satisfies RATC ≧ 0.6. At this point <h>, the integration process is started to enhance the controllability. At the point <f>, the actual engine speed NE is equal to the target engine speed NESPR. Matches. For this reason, a shift delay occurs.

However, in the present invention, "A: (RATC <0.6). (E1R <0)"
Alternatively, in the case of (RATC> 2.04) · (E1R> 0), the integration process is prohibited ”, since the integration is started immediately when the first error E1R> 0, the actual engine speed NE becomes the target engine at the point <e>. This will match the rotational speed NESPR, and there will be no shift delay.

〔The invention's effect〕

As described above, according to the present invention, the intermediate speed ratio region is set between the overdrive line and the full line which are the speed ratio limit values determined by the mechanical dimensions of the components of the continuously variable transmission, and the target engine speed is set. Control means for performing a speed change control so as to change a speed ratio by performing a proportional process and an integral process on an error between the engine speed and the actual engine speed, and this control means causes an overdrive side trigger to be provided in the intermediate speed ratio region side of the overdrive line. A value line is set and a full low side trigger value line is set on the intermediate speed ratio area side of the full low line. By this control means, the actual speed ratio of the continuously variable transmission is set to the overdrive side trigger value line and the full low side. When shifting beyond the trigger value line to the vicinity of the overdrive line and the full low line which are the gear ratio limit values The gear ratio is controlled so as to change the gear ratio by inhibiting the integration process, and the vicinity of the overdrive line and the full low line which are the gear ratio limit values beyond the overdrive side trigger value line and the full low side trigger value line. When shifting the shifted speed ratio to the intermediate speed ratio region side, by performing the speed change control to allow the integration process and change the speed ratio, the integrated value is unnecessarily accumulated and becomes an abnormal value. Can be prevented, and not only proportional processing but also necessary integral processing can be performed.

For this reason, it is possible to eliminate the adverse effect of the shift control due to the abnormal integrated value, thereby avoiding a decrease in the followability of the target engine speed, and avoiding the occurrence of a shift delay due to the prohibition of the simple integration process. obtain.

[Brief description of the drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is a flowchart for explaining the operation, FIG. 2 is a control block diagram, and FIG. 3 is a line of a ratio line with respect to an engine speed and a clutch output speed. FIG. 4 is a diagram of an error, an integral value, an engine speed, and time, and FIG. 5 is a hydraulic circuit diagram of the continuously variable transmission. In the figure, 2 is a continuously variable transmission, 4 is a belt, 6 is a driving pulley, 12 is a driven pulley, 18 is an input shaft, 20 is an output shaft, 32 is an oil pump, 42 is a primary pressure control valve, 46
Is a constant pressure control valve, 50 is a first three-way solenoid valve for a primary pressure control valve, 52 is a line pressure control valve, 58 is a second three-way solenoid valve for a line pressure control valve, 60 is a clutch pressure control valve, and 66 is a clutch pressure control A third three-way solenoid valve for a valve, 70 is a hydraulic clutch, 78 is a pressure sensor, 88 is a first rotation detector, 92 is a second rotation detector, 110
Is a control unit.

Claims (1)

(57) [Claims] A pulley having a fixed pulley part and a movable pulley part detachably mounted on the fixed pulley part is wound around both pulleys by reducing the groove width between the two pulley parts. In a shift control method for a continuously variable transmission, the shift control is performed to change the speed ratio by increasing or decreasing the rotation radius of the belt.
An intermediate speed ratio region is set between the overdrive line and the full line, which are the speed ratio limit values determined by the mechanical dimensions of the components of the continuously variable transmission, and an error between the target engine speed and the actual engine speed. Control means for shifting the gear ratio so as to change the gear ratio by performing a proportional process and an integral process. The control means sets an overdrive-side trigger value line on the intermediate speed ratio region side of the overdrive line and sets the full low A full low trigger value line is set on the intermediate speed ratio region side of the line, and the control means causes the actual speed ratio of the continuously variable transmission to exceed the overdrive side trigger value line and the full low side trigger value line, thereby setting the speed ratio. In the case of shifting to the vicinity of the overdrive line and the full low line which are the limit values, the integration process is prohibited. The gear ratio control is performed so as to change the speed ratio, and the actual gear ratio shifted to the vicinity of the overdrive line and the full low line as the gear ratio limit values beyond the overdrive side trigger value line and the full low side trigger value line is set to the intermediate value. A shift control method for a continuously variable transmission, wherein the shift control is performed so as to change the speed ratio while permitting the integration process when shifting to the speed ratio region side.