JP3475665B2 - Transmission control device for continuously variable transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a shift control device for a vehicle equipped with a continuously variable transmission.

[0002]

2. Description of the Related Art In a continuously variable transmission used in a vehicle, a vehicle speed VSP and a throttle opening TVO (or an accelerator opening AC
Based on S), the target input shaft rotation speed (target gear ratio) is determined and gear shifting is performed. During this gear shifting, the gear shifting speed is kept within the target value in order to suppress torque fluctuations. The shift shock caused by the drive system inertia torque is reduced. Then, as the control for obtaining the target value of the gear ratio, the target gear ratio and an actual gear ratio value PI (proportional, integral) performs feedback control of the control are common.

[0003]

However, in the above-described conventional shift control device, the above-described control is performed by obtaining the respective rotation speeds of the input and output shafts and obtaining the actual shift speed from these ratios. The input shaft rotation speed and the output shaft rotation speed each include an error. Therefore, when the gear ratio control is performed based on the obtained gear speed, the gear ratio control amount fluctuates. There has been a problem that the rotational speed fluctuates due to gear shifting and impairs drivability.

Therefore, the present invention has been made in view of the above problems, and provides a shift control device for a continuously variable transmission capable of suppressing the variation of the gear ratio by minimizing the influence of the error in the rotation speed measurement. The purpose is to

[0005]

According to a first aspect of the present invention, an input / output disk for sandwiching a power roller with a toroidal opposed surface and a tiltable support for the power roller are provided.
In a transmission control device for a continuously variable transmission equipped with a trunnion which is driven by an actuator and is displaceable in the axial direction, a means for setting a target input rotation speed of the continuously variable transmission from a driving state of a vehicle, and the target input. Means for obtaining a feedback control amount of the actuator based on the difference between the rotational speed and the actual input rotational speed, and a target speed change ratio obtained from the target input rotational speed and the output rotational speed of the continuously variable transmission, and the target speed change ratio. means for determining a speed control amount of the actuator from the change amount of the target tilting angle itself corresponding to, and controls the actuator by controlling the amount of the sum of the speed control amount of the feedback control amount of the actuator actuator.

In a second aspect based on the first aspect, the speed control gain of the actuator is such that the vehicle speed is high.
The smaller it gets, the smaller.

In a third aspect based on the first aspect, the speed control gain of the actuator has a gear ratio
It becomes smaller toward the Hi side .

[0008]

Therefore, the present invention depends on the target tilt angle.
Feedforward the speed control amount of the actuator
Therefore, by giving in advance, incorrect measurement of the input / output shaft rotation speed
Stable target tilting speed (∝ shift speed
Degree), and includes the error as in the conventional example.
It is no longer controlled by the actual shift speed,
It is possible to suppress the change in gear ratio while suppressing the change in
To improve the drivability of vehicles equipped with a continuously variable transmission.
It is possible to

[0010]

[0011]

[0012]

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the continuously variable transmission 10 (CVT in the figure) is set to a predetermined gear ratio according to the operating condition of the vehicle by the gear ratio changing means 9 controlled by the gear shift control controller 2. As the continuously variable transmission 10, for example, as shown in FIG. 2, an input / output disk (not shown)
The toroidal type continuously variable transmission capable of changing the gear ratio in accordance with the tilt angle of the power roller 18c sandwiched between the power roller 18c and the gear ratio changing means 9 is driven by the step motor 61 as shown in FIG. The case where the control valve 60 is used is shown.

Between the engine 1 and the continuously variable transmission 10,
A torque converter T / C as a fluid transmission unit including a lockup clutch L / U is provided.

The shift control controller 2 reads the opening TVO (or accelerator pedal opening ACS) of a throttle (not shown) that responds to the driver's operation and the engine speed Ne detected by the crank angle sensor 8. , The input shaft rotation speed N detected by the input shaft rotation sensor 6 of the continuously variable transmission 10.
t (that is, the turbine rotation speed of the torque converter T / C) and the output shaft rotation speed N detected by the output shaft rotation sensor 7
As shown in FIG. 12, the actual target input shaft speed RREV corresponding to the operating condition is obtained from the preset shift map, and is input to the step motor 61 (see FIG. 2) of the gear ratio changing means 9 as shown in FIG. The control amount ASTP is commanded according to the target gear ratio RTO and the feedback control amount (FB control amount) by the PI control, and the relationship between the drive amount of the step motor 61 and the gear ratio is set as shown in FIG.

The gear ratio changing means 9 is shown in FIG.
As shown in FIG. 7, the actual speed ratio changes according to the hydraulic actuator 50 that axially drives the trunnion shaft 50a that supports the power roller 18c of the continuously variable transmission 10, the driving of the step motor 61, and the displacement of the trunnion shaft 50a. A control valve 60 that supplies pressure oil to the hydraulic actuator 50 while feeding back the hydraulic pressure is fed back, and the step motor 61 drives the spool 63 in response to a command from the shift control controller 2,
The hydraulic pressure is supplied to and discharged from the oil chambers 50H and 50L above and below the piston 50P.

On the other hand, the trunnion shaft 50 corresponding to this hydraulic pressure
axial displacement of a and axial displacement (= power roller 18
The tilting angle of c) is the profile mechanism 6 including the link.
The hydraulic pressure to the hydraulic actuator 50 is fed back to the sleeve 64 that moves relative to the spool 63 via the step motor 6 according to the target gear ratio RTO.
1 and the tilt angle of the power roller 18c, that is, the actual gear ratio RTO, and this gear ratio is uniquely determined according to the drive amount of the step motor 61 as shown in FIG. It is determined.

As shown in the conceptual diagrams of FIGS. 3 and 4, the shift control controller 2 includes a vehicle speed VSP and a throttle opening TV.
Using O (or accelerator opening, the same applies below) as a parameter, a gear shift determination unit that obtains the actual target input shaft rotational speed RREV in response to the vehicle operating condition and the driver's request, and the actual target input shaft rotational speed RREV and the actual According to the deviation of the input shaft speed Nt, for example, a feedback control unit by PI control and a shift control unit that drives a step motor 61 (actuator in the figure) according to the target gear ratio RTO and the feedback control amount are roughly classified. To be done.

Here, an example of the control performed by the shift control controller 2 is shown in the flow charts of FIGS.
The details will be described below with reference to the conceptual diagrams of FIGS.
In addition, each flowchart is for a predetermined time, for example, 10 msec.
It is executed for each.

First, FIG. 5 is a flow chart of the signal measuring process for detecting the operating state of the vehicle. In step S1, the throttle opening TVO and the engine speed Ne are read as the operating state of the engine 1, while the continuously variable transmission 10 is read. The input shaft rotation speed Nt and the output shaft rotation speed No are read from.

Then, in step S2, each value indicating the operating state of the vehicle is calculated. First, the output shaft speed No is multiplied by the conversion constant A to obtain the vehicle speed VSP.
The actual gear ratio RTO is calculated from the ratio of the input shaft speed Nt and the output shaft speed No, and the engine speed Ne and the throttle opening TVO
From this, the estimated engine torque Tin is calculated from the preset map shown in FIG.

Next, the flow chart of FIG. 6 is carried out based on the operating condition obtained in steps S1 and S2.
1 shows an outline of shift control of the continuously variable transmission 10.

In step S3, as will be described later, the target input shaft rotation speed map value RREV is set according to the driving state of the vehicle.
0 and the target gear ratio map value RTO0 are respectively calculated,
It is a shift determining unit that determines the actual target input shaft rotational speed RREV with a first-order lag, and this shift determining unit is equivalent to the conceptual diagrams of FIGS. 3 and 4.

Then, in step S4, based on the actual target input shaft rotation speed RREV obtained in step S3,
The control amount ASTP of the step motor 61 is calculated, which corresponds to the shift control unit in FIG.

As shown in the flow chart of FIG. 7, the gear shift control section obtains the control position FSTP of the step motor 61 according to the target gear ratio RTO in step S5, and in step S6 executes the step motor by PI (proportional integration) control. 6
The control amount FBSTP of 1 is calculated, and the control amount ASTP corresponding to the response characteristic of the step motor 61 is obtained in step S7.

Then, the control amount ASTP is instructed to the step motor 61 in step S8 of FIG. 8 to drive the gear ratio changing means 9.

First, step S3 of FIG. 6 and FIG.
Details of the shift determination unit shown in the block diagram of FIG. 9 will be described based on the flowchart of FIG.

Step S30 is the target rotation speed search unit shown in FIG. 4, and as described above, the target input shaft rotation speed map value RREV0 is obtained from the vehicle speed VSP and the throttle opening TVO based on the map shown in FIG. .

Step 31 and subsequent steps show the rotational speed change amount determining unit of FIG. 4, and first, in step 31, the previous actual target input shaft rotational speed RREV is stored in RREVold, and then in step S32, the target rotational speed is temporarily changed. The delay time constant Kr is set to a predetermined value K1.

Then, in step S33, based on the following equation, the actual target input shaft of the primary delay based on the following equation from the target input shaft rotational speed map value RREV0, the previous value actual target input shaft rotational speed RREVold, and the primary delay time constant Kr. The rotation speed RREV is calculated.

RREV = (RREV0 + RREVold × Kr) / (Kr + 1) (1) Therefore, the relationship between the target input shaft speed map value RREV0 and the actual target input shaft speed RREV is as shown in FIG. The actual target input shaft rotation speed RREV gradually increases toward the map value RREV0 according to the next delay time constant Kr.

In step S34, the target speed ratio RTO0 is calculated from the ratio of the temporary target actual input shaft speed RREV obtained by the above equation (1) and the output shaft speed No of the continuously variable transmission 10.
End in search of.

Next, the shift control amount calculation and feedback control amount calculation unit in steps S5 and S6 will be described with reference to FIG.
This will be described with reference to the flowchart of No. 0. Note that steps S50 to S56 indicate a shift control amount calculation unit, and subsequent steps S60 to S64 indicate a feedback control amount calculation unit.

In step S50, the above step S34 is performed.
Based on the map of target speed ratio RTO0-actual target speed ratio RTO1 shown in FIG. 14, from the target speed ratio RTO0 calculated in step S2 and the estimated engine torque Tin calculated in step S2, the actual target engine speed Tin is used as a parameter. The gear ratio RTO1 is calculated.

In the map of FIG. 14, the actual target gear ratio RTO1 is made variable according to the input torque = the estimated engine torque Tin in order to avoid the influence of the torque shift generated in the toroidal type continuously variable transmission 10. , Which is preset according to the characteristics of the continuously variable transmission 10.

In step S51, the actual target gear ratio R
The control step number FSTP, which is the drive amount of the step motor 61, is calculated from TO1 from the map of FIG.
In step S52, the current tilt angle RPHI of the power roller 18c is stored as the previous value RPHIold,
In step S53, the target value of the tilt angle RPHI is calculated.

This tilt angle RPHI and tilt speed dRPHI
Also, the relationship between the displacement amount Y of the trunnion shaft 50a driven by the hydraulic actuator 50 of FIG.

Y = dφ × f (φ) × ωp (2) where φ: tilt angle dφ: tilt speed [rad / sec] f (φ): determined according to the geometry of the continuously variable transmission Characteristic ωp: Power roller rotation speed From this equation (2), if the target value of the tilt angle RPHI = φ, the target value of the shift speed = tilt speed dRPHI = dφ and the rotation speed ωp of the power roller 18c are given, the hydraulic pressure is calculated. The displacement amount Y of the actuator 50 can be estimated.

The displacement of the trunnion shaft 50a around the shaft and in the axial direction according to the tilting of the power roller 18c is fed back to the sleeve 64 via a tracing mechanism 67 having a link, and the displacement amount dx2 of this sleeve 64 is fed back.
Is given by the following equation, where the link ratio of the tracing mechanism 67 is L.

Dx2 = Y × L (3) The number of steps DSTP of the step motor 61 according to the displacement amount dx2 of the sleeve 64 is DSTP = dx2 × B (when the gain of the step motor 61 is B). 4) The displacement amount dx2 of the sleeve 64 is the step motor 6
The control amount DSTP can be obtained from the estimated displacement amount Y of the hydraulic actuator 50, which is converted into the control amount DSTP of 1.

Next, in step S52, the previous tilt angle RPHI is stored in the previous value RPHIold, and in step S53, the target tilt angle RPHI is calculated from the actual target gear ratio RTO1 obtained in step S50. . This target tilt angle RPHI is a value that is uniquely determined from the actual target gear ratio RTO1.

In step S54, the current target tilt angle R
A value obtained by multiplying the difference between PHI and the previous value RPHIold by 100 is calculated as the target tilting speed dRPHI.

DRPHI = (RPHI−RPHIold) × 100 (5) From the above target tilt angle RPHI and vehicle speed VSP, in step 55, the tilt motor angle RPHI is used as a parameter from the map of FIG. The gain B, which is a conversion coefficient, is obtained as the speed gain KSPD.

Here, the number of steps DSTP of the step motor 61 according to the displacement amount dx2 of the sleeve 64 is DSTP = dRPHI × KSPD (6) from the above equations (2) to (4), and step S56 Then, from the equation (6), the number of steps DST of the step motor 61, which is the shift speed control amount,
Calculate P.

In the feedback control amount calculation subsequently performed, first, in step S61, the actual target input shaft rotational speed RR is calculated.
The difference Nerr between the EV and the input shaft rotation speed Nt is obtained, and in step S61, the integrated value of this rotation speed difference Nerr is calculated as Ni.

Then, in step S62, the rotation speed difference Ner
By multiplying r by a predetermined proportional gain kp, the proportional portion FBp of the feedback control amount is calculated. The proportional gain kp is determined from a predetermined map or function corresponding to the actual gear ratio RTO and the vehicle speed VSP.

In step S63, the above step S61 is performed.
The integral value FBi of the feedback control amount is calculated by multiplying the integral value Ni of the rotational speed difference obtained in step 1 by a predetermined integral gain ki. It should be noted that the integral gain ki is based on the actual gear ratio RTO and the vehicle speed VS.
It is determined from a predetermined map or function corresponding to P.

Thus, in step S64, the proportional component F
The feedback control amount FB is calculated from the sum of Bp and the integral FBi.
Find the STP (number of steps).

Next, the step motor control section shown in step 7 of FIG. 7 executes the subroutine shown in FIG.

First, in step S70, the above step S
The sum of the control step number FSTP obtained in 51 and the feedback control amount FBSTP and speed control amount DSTP obtained in step S64 is obtained as the target step number DSRSTP.

Then, in steps S71 to S76, the control amount ASTP is determined from the target step number DSRSTP and the current control amount ASTP according to the response speed of the step motor 61.
Is calculated and the target control amount DSRSTP is larger than the current control amount ASTP, the control amount ASTP is set as a unit.
The time control amount PSTP is increased by the target value DSRSTP.

That is, in FIG. 18, the speed control amount PS which is the change amount of the step motor 61 per unit time is shown.
TP is the control amount A actually output to the step motor 61.
Increase or decrease until STP reaches the target control amount DSRSTP,
The step motor 61 is driven so that the spool 63 of the control valve 60 has a predetermined gear ratio.

In this way, the control amount ASTP obtained from the flowcharts of FIGS. 5 to 11 is output from the shift control controller 2 to the step motor 61 in step S9 of the signal output unit of FIG. 8 to calculate the power roller 18c. The continuously variable transmission 10 is tilted at the tilting speed dRPHI and set to the actual target gear ratio RTO1.

In this way, when performing gear shifting, the actual target gear ratio RTO1 that compensates for torque shift is set by feedforward (steps S50 to 51), and the target tilt angle d is set.
By previously giving the control amount DSTP of the step motor 61 according to the displacement amount Y of the hydraulic actuator 50 estimated from the RPHI , the vehicle speed VSP, and the target tilting speed dRPHI, the influence of the measurement error of the input / output shaft rotational speed is suppressed. It is possible to obtain a stable target tilting speed dRPHI ( ∝shift speed), and it is possible to perform shift speed control without using the actual shift speed as in the above-mentioned conventional example. Since it is not necessary to control the actual shift speed that includes an error, it is possible to suppress the change in shift speed while suppressing torque fluctuation, and it is possible to improve the drivability of a vehicle equipped with a continuously variable transmission. It becomes.

Further, the speed gain KSPD is variably controlled according to the vehicle speed VSP using the tilt angle RPHI (or gear ratio) as a parameter as shown in FIG. 16, so that a smooth gear change can be performed according to the operating condition. You can

In the above embodiment, the feedback control is performed based on the rotational speed difference Nerr of the input shaft, but although not shown, the same operational effect can be obtained by performing the feedback control based on the difference between the gear ratio and the tilt angle. Can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a continuously variable transmission showing an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a gear ratio changing unit.

FIG. 3 is a block diagram showing an outline of shift control.

FIG. 4 is a block diagram showing an outline of a shift determination unit.

FIG. 5 is a flowchart showing an example of control performed by a shift control controller, showing a signal measurement process.

FIG. 6 is a flowchart similarly showing an example of control, in which C
An outline of the VT control process is shown.

FIG. 7 is a flow chart showing an example of control, showing an outline of a shift control unit.

FIG. 8 is a flowchart showing an example of control, showing a signal output process.

FIG. 9 is a flowchart showing the details of a shift determination unit that is also performed in CVT control processing.

FIG. 10 is a flowchart showing details of a shift control amount calculation unit and an FB control calculation unit, which are also performed by the shift control unit.

FIG. 11 is a flowchart showing the details of the step motor control unit in the same manner.

FIG. 12 is a shift map showing the relationship between the target input shaft speed RREV and the vehicle speed VSP with the throttle opening TVO as a parameter.

FIG. 13 is a torque map showing the relationship between the engine speed Ne and the engine torque Te with the throttle opening TVO as a parameter.

FIG. 14: Actual target gear ratio RTO1 and target gear ratio RTO0
The graph which shows the relationship of.

FIG. 15: Target step number FSTP and actual target gear ratio RT
The graph which shows the relationship of O1.

FIG. 16 is a vehicle speed VS with the tilt angle RPHI as a parameter.
Speed gain KSP showing the relationship between P and speed gain KSPD
The characteristic view of D.

FIG. 17 is a graph showing the relationship between the map search target rotation speed RREV0 and the actual target input shaft rotation speed RREV.

FIG. 18 is a graph showing the relationship between the target step number DSRSTP and the actual output step number ASTP.

[Explanation of symbols]

1 engine 2 Shift control controller 6 Input shaft rotation sensor 7 Output shaft rotation sensor 8 crank angle sensor 9 Gear ratio changing means 10 continuously variable transmission 18c power roller 60 control valve 61 step motor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F16H 101: 04 F16H 101: 04 (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] 1. An input / output disk that holds a power roller between opposing surfaces of a toroidal shape, and a trunnion that supports the power roller in a tiltable manner and is axially displaceable by being driven by an actuator. In a shift control device for a continuously variable transmission, means for setting a target input speed of the continuously variable transmission from a driving state of a vehicle, and a means for setting the target input speed of the actuator based on a difference between the target input speed and an actual input speed. A means for obtaining a feedback control amount, a target gear ratio is obtained from the target input speed and the output speed of the continuously variable transmission, and a target tilt angle corresponding to the target speed ratio.
Means for the variation of itself determine the speed control amount of the actuator, the feedback control amount of the actuator action
A shift control device for a continuously variable transmission, characterized in that the actuator is controlled by a control amount that is a sum of speed control amounts of a chutator . 2. The speed control gain of the actuator is
The shift control device for a continuously variable transmission according to claim 1, wherein the shift control device is reduced as the vehicle speed increases . 3. The speed control gain of the actuator is
The shift control device for a continuously variable transmission according to claim 1, wherein the shift ratio is reduced as the shift ratio is closer to the Hi side .