JPH1054455A - Shift controller for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the fluctuation of the gear shifting speed by preventing the effect of the error of measurement of the number of revolutions. SOLUTION: A shift controller of a continuously variable transmission is provided with input and output disks 101 for pinching a power roller 100 on the toroidal facing surfaces, a trunnion 103 for supporting the power roller 100 so that the power roller may be freely and slantly rotated, and capable of being displaced in the axial direction by being driven by an actuator 102, a target gear ratio setting means 110 for calculating the target gear ratio according to the operating state of a vehicle, and a shift control means 111 for controlling the actuator 102 according to the target gear ratio. Moreover, it is provided with a displacement amount estimating means 112 for estimating the displacement amount of the trunnion 103, and a gear shifting speed setting means 113 for setting the target gear shifting speed on the basis of the estimated displacement amount of the trunnion 103, and the speed change control means 111 drives the actuator 102 according to the target gear ratio and the target gear shifting speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A continuously variable transmission used in a vehicle has a vehicle speed VSP and a throttle opening TVO (or an accelerator opening AC).
S), the target input shaft rotation speed (target gear ratio) is determined to perform gear shifting. During this gear shifting, the gear speed is set within the target value in order to suppress torque fluctuation. Shift shock caused by the inertia torque of the drive system is reduced. Then, as control for obtaining the target value of the shift speed,
Generally, the difference between the target shift speed and the actual shift speed is performed by feedback control such as PI (proportional or integral) control.

[0003]

However, in the conventional shift control device, the control is performed by determining the rotational speed of the input and output shafts and determining the actual shift speed from the ratio. The input shaft rotation speed and the output shaft rotation speed each include an error. Therefore, if the speed change speed control is performed based on the obtained speed change speed, the speed change speed control amount fluctuates. However, there is a problem that the driving performance is impaired and the drivability is impaired.

Accordingly, 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 a change in shift speed by minimizing the influence of an error in the rotation speed measurement. The purpose is to:

[0005]

According to a first aspect of the present invention, as shown in FIG.
And a trunnion 10 that supports the power roller 100 in a tiltable manner and that can be displaced in the axial direction by being driven by an actuator 102.
3, a target gear ratio setting unit 110 for calculating a target gear ratio according to the driving state of the vehicle, and a gear control unit 111 for controlling the actuator 102 according to the target gear ratio.
In the shift control device for a continuously variable transmission, the displacement estimating means 11 for estimating the displacement of the trunnion 103 is provided.
2, and a shift speed setting means 113 for setting a target shift speed based on the estimated displacement of the trunnion 103. The shift control means 111 drives the actuator 102 according to the target shift ratio and the target shift speed.

In a second aspect based on the first aspect, the shift control means 111 variably controls the shift speed in accordance with the vehicle speed.

In a third aspect based on the first aspect, the shift control means 111 variably controls the shift speed in accordance with the vehicle speed using the speed ratio as a parameter.

In a fourth aspect based on the first aspect, the displacement amount estimating means 112 includes the power roller 1.
The displacement amount of the trunnion 103 is estimated based on the target tilt angle of 00, the target tilt speed of the power roller, and the rotation speed of the power roller 100.

[0009]

Therefore, according to the first aspect of the present invention, the actuator is driven toward the target gear ratio when performing a gear shift,
The power ratio is changed by tilting of the power roller in accordance with the axial displacement of the trunnion, but the speed change speed at this time is set based on the estimated displacement of the trunnion. Is not required to be controlled by the actual transmission speed, and the fluctuation of the transmission speed can be suppressed, so that the drivability of the vehicle including the continuously variable transmission can be improved.

According to the second aspect of the present invention, since the shift speed is variably controlled according to the vehicle speed, a smooth shift can be performed according to the driving state.

In a third aspect of the present invention, the transmission control means includes:
Since the transmission speed is variably controlled in accordance with the vehicle speed using the transmission ratio as a parameter, a smoother transmission can be performed according to the driving state.

According to a fourth aspect of the present invention, the displacement of the trunnion is estimated on the basis of the target tilt angle, the target tilt speed, and the number of rotations of the power roller, and includes an error as in the prior art. However, it is no longer possible to control with the actual shift speed, and it is possible to prevent a change in the shift speed,
Drivability of a vehicle including the continuously variable transmission can be improved.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

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

[0015] Between the engine 1 and the continuously variable transmission 10,
A torque converter T / C as a fluid transmission means having a lock-up clutch L / U is interposed.

The shift control controller 2 reads the opening TVO (or accelerator pedal opening ACS) of a throttle (not shown) responsive 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 (ie, the turbine speed of the torque converter T / C) and the output shaft speed N detected by the output shaft speed sensor 7
o, and as shown in FIG. 12, an actual target input shaft rotation speed RREV corresponding to the operating state is obtained from a preset shift map, and is sent to the step motor 61 of the speed ratio changing means 9 (see FIG. 2). The control amount ASTP is instructed according to the target speed ratio RTO and the feedback control amount (FB control amount) by PI control. The relationship between the drive amount of the step motor 61 and the speed ratio is set as shown in FIG.

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

On the other hand, the trunnion shaft 50 corresponding to the hydraulic pressure
a in the axial direction and the displacement around the axis (= power roller 18)
The tilting mechanism 6 includes a link.
7, the pressure is fed back to the sleeve 64 that moves relative to the spool 63, and the hydraulic pressure to the hydraulic actuator 50 is adjusted by the step motor 6 according to the target speed 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 speed change controller 2 controls the vehicle speed VSP and the throttle opening TV.
A shift determining unit that obtains an actual target input shaft rotation speed RREV according to the driving state of the vehicle and the driver's request using O (or accelerator opening, the same applies hereinafter) as a parameter; For example, a feedback control unit based on PI control according to the deviation of the input shaft rotation speed Nt, and a shift control unit driving the step motor 61 (actuator in the figure) according to the target speed ratio RTO and the feedback control amount. Is done.

Here, an example of the control performed by the transmission control controller 2 is shown in the flowcharts of FIGS.
The details will be described below with reference to the conceptual diagrams of FIGS.
Each flowchart is performed at predetermined time intervals, for example, 10 msec.
It is executed each time.

First, FIG. 5 is a flowchart of a 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 operated. , The input shaft rotation speed Nt and the output shaft rotation speed No are respectively read.

In step S2, each value indicating the driving state of the vehicle is calculated. First, the vehicle speed VSP is obtained by multiplying the output shaft rotational speed No by the conversion constant A.
The actual gear ratio RTO is calculated from the ratio between the input shaft rotation speed Nt and the output shaft rotation speed No, and the engine speed Ne and the throttle opening TVO
Then, the estimated engine torque Tin is calculated from the preset map shown in FIG.

Next, the flowchart of FIG. 6 is performed based on the operating state obtained in steps S1 and S2.
1 shows an outline of shift control of a continuously variable transmission 10.

In step S3, as will be described later, a target input shaft rotation speed map value RREV is set in accordance with the driving state of the vehicle.
0, the target gear ratio map value RTO0 is calculated,
This is a shift determining unit that determines the actual target input shaft rotation speed RREV with a first-order delay. This shift determining unit is equivalent to the conceptual diagrams of FIGS.

In step S4, based on the actual target input shaft rotation speed RREV obtained in step S3,
It calculates the control amount ASTP of the step motor 61, and corresponds to the shift control unit in FIG.

As shown in the flow chart of FIG. 7, this shift control unit obtains the control position FSTP of the step motor 61 in accordance with the target speed ratio RTO in step S5, and in step S6, controls the step motor by PI (proportional integration) control. 6
A control amount FBSTP of 1 is calculated, and a control amount ASTP corresponding to the response characteristic of the step motor 61 is obtained in step S7.

The control amount ASTP is commanded to the stepping motor 61 in step S8 in FIG. 8 to drive the speed ratio changing means 9.

First, step S3 in FIG. 6 and FIG.
The details of the shift determination unit shown in the block diagram of FIG.

Step S30 shows the target rotational speed search section shown in FIG. 4, and as described above, determines the target input shaft rotational speed map value RREV0 from the vehicle speed VSP and the throttle opening TVO based on the map shown in FIG. .

Steps 31 and subsequent steps show the rotation speed change amount determination unit in FIG. 4. First, in step 31, the previous actual target input shaft rotation speed RREV is stored in RREVold. The delay time constant Kr is set to a predetermined value K1.

In step S33, based on the target input shaft rotation speed map value RREV0, the previous value actual target input shaft rotation speed RREVold, and the first-order lag time constant Kr, the first-order actual target input shaft rotation is calculated based on the following equation. The rotation speed RREV is calculated.

RREV = (RREV0 + RREVold × Kr) / (Kr + 1) (1) Accordingly, 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 change ratio RTO0 is calculated from the ratio of the temporarily delayed actual target input shaft speed RREV calculated by the above equation (1) to the output shaft speed No of the continuously variable transmission 10.
And end.

Next, the shift control amount calculation and feedback control amount calculation section in steps S5 and S6 will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. Steps S50 to S56 indicate a shift control amount calculation unit, and steps S60 to S64 indicate a feedback control amount calculation unit.

In step S50, the above-mentioned step S34 is executed.
Based on the target speed ratio RTO0 obtained in step S2 and the estimated engine torque Tin obtained in step S2, based on the target speed ratio RTO0-actual target speed ratio RTO1 map shown in FIG. The gear ratio RTO1 is calculated.

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

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

The tilt angle RPHI and the tilt speed dRPHI
The relationship between the displacement Y of the trunnion shaft 50a driven by the hydraulic actuator 50 in FIG. 2 is as follows.

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 the equation (2), given 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, The displacement amount Y of the actuator 50 can be estimated.

The displacement of the trunnion shaft 50a around the axis and in the axial direction in response to the tilt of the power roller 18c is fed back to the sleeve 64 via the linking mechanism 67, and the displacement dx2 of the sleeve 64 is provided.
Is as follows when the link ratio of the copying mechanism 67 is L.

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

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 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 displacement speed dRPHI.

DRPHI = (RPHI−RPHIold) × 100 (5) Based on the target tilt angle RPHI and the vehicle speed VSP, in step 55, the step motor control amount is determined from the map of FIG. 16 using the tilt angle RPHI as a parameter. Gain B, which is a conversion coefficient, is obtained as speed gain KSPD.

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

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

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

In step S63, the above-mentioned step S61
Is multiplied by a predetermined integral gain ki to calculate the integral FBi of the feedback control amount. Note that the integral gain ki is determined by the actual speed 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
From the sum of Bp and the integral FBi, the feedback control amount FB
STP (the number of steps) is obtained.

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

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

In steps S71 to S76, the control amount ASTP is calculated 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 if the target control amount DSRSTP is larger than the current control amount ASTP, the control amount ASTP is increased by the target value DSTP by the control amount DSTP obtained in step S56.
Increase to RSTP.

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

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

As described above, when shifting, the actual target gear ratio RTO1 that compensates for the torque shift is set by feedforward (steps S50 to S51), and the target tilt angle R is set.
By giving in advance the control amount DSTP of the step motor 61 according to the displacement Y of the hydraulic actuator 50 estimated from the PHI, the vehicle speed VSP, and the target displacement speed dRPHI, the influence of the measurement error of the input / output shaft rotation speed can be suppressed. A stable target tilting speed RPHI (∝ shift speed) can be obtained, and the shift speed control can be performed without using the actual shift speed as in the conventional example. Control is no longer performed using the actual shift speed that includes the error, and it is possible to suppress the change in the shift speed while suppressing the torque change, thereby improving the operability of a vehicle equipped with a continuously variable transmission. It becomes.

Further, as shown in FIG. 16, the speed gain KSPD is variably controlled in accordance with the vehicle speed VSP using the tilt angle RPHI (or gear ratio) as a parameter. Can be.

In the above-described embodiment, the feedback control is performed based on the rotation speed difference Nerr of the input shaft. Can be obtained.

[Brief description of the 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 gear ratio changing means.

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

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

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

FIG. 6 is a flowchart showing an example of the control, wherein C
The outline of the VT control process will be described.

FIG. 7 is a flowchart showing an example of control, and shows an outline of a shift control unit.

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

FIG. 9 is a flowchart illustrating details of a shift determination unit similarly 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 details of a step motor control unit.

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

FIG. 14 shows an actual target gear ratio RTO1 and a target gear ratio RTO0.
The graph which shows the relationship.

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

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

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

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

FIG. 19 is a claim correspondence diagram corresponding to any one of the first to fourth inventions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 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 100 Power roller 101 Input / output disk 102 Actuator 103 Trunnion 110 target gear ratio setting means 111 gear shift control means 112 displacement amount estimating means 113 gear speed setting means

Claims (4)

[Claims] 1. An input / output disk for holding a power roller between opposed toroidal surfaces, a trunnion for supporting the power roller in a tiltable manner and being axially displaceable by being driven by an actuator. A transmission control device for a continuously variable transmission, comprising: a target transmission ratio setting unit that calculates a target transmission ratio according to an operation state; and a transmission control unit that controls the actuator according to the target transmission ratio. A shift amount estimating unit for estimating a displacement amount; and a shift speed setting unit for setting a target shift speed based on the estimated displacement amount of the trunnion. The shift control unit drives an actuator according to a target gear ratio and a target gear speed. A shift control device for a continuously variable transmission, comprising: 2. The shift control device for a continuously variable transmission according to claim 1, wherein said shift control means variably controls a shift speed according to a vehicle speed. 3. The shift control device for a continuously variable transmission according to claim 1, wherein the shift control means variably controls the shift speed in accordance with a vehicle speed using a speed ratio as a parameter. 4. The displacement amount estimating means estimates a displacement amount of a trunnion based on a target tilt angle of the power roller, a target tilt speed of the power roller, and a rotation speed of the power roller. The shift control device for a continuously variable transmission according to claim 1.