JP2699324B2 - Hydraulic control method for belt type continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical field   The present invention relates to a hydraulic control method for a belt-type continuously variable transmission.
And in particular to improve the control characteristics of the speed ratio of the continuously variable transmission.
It is about technology. Conventional technology   One type of belt type continuously variable transmission, input shaft and output shaft
And a pair of input sides provided on the input shaft and the output shaft.
A variable pulley, an output variable pulley, and the input variable pulley;
Transmission bell wound between the shaft and the output side variable pulley
And the input-side variable pulley and the output-side variable pulley.
Input side hydraulic cylinder and output side hydraulic pressure to change V groove width
Hydraulic oil flows into the cylinder and the input hydraulic cylinder.
The hydraulic oil from the input side hydraulic cylinder.
Shift direction switching valve that switches to the
Hydraulic oil flowing into the cylinder or its input hydraulic cylinder
Do not restrict the flow rate of the hydraulic oil flowing out of the
Speed control selectively operated in two positions
There is a belt-type continuously variable transmission equipped with a control valve. like this
In a belt-type continuously variable transmission, the actual rotational speed of the input shaft
The shift direction switching valve so that the degree matches the target rotational speed.
While controlling the deviation between the actual rotational speed and the target rotational speed.
When the difference is within a predetermined first criterion value,
The control valve is switched to the flow suppression state, but the deviation is the first judgment
Between the reference value and before reaching the second judgment reference value
The shift speed control valve is periodically repeated between the two positions.
Hydraulic control of the type that operates to control the flow rate at an intermediate speed
Control method is adopted. For example, JP-A-60-95262
That is what is described in the gazette.   According to such a hydraulic control method, the deviation is determined by the first determination.
If the reference value is exceeded, the speed control valve will cycle between the two positions.
Are repeatedly operated, so that the two positions
Belt type at an intermediate speed between the minimum and maximum speed
The speed ratio of the continuously variable transmission is changed to
Improved control characteristics when making the speed follow the target rotation speed
Is done. In other words, the driving state requested by the driver
Target input shaft rotation speed determined for cost ratio
The actual input shaft rotation speed for the change of degree or target gear ratio
Speed or gear ratio can be tracked sufficiently.
While the hunting phenomenon in the passing state is eliminated,
Engine vibration and drivability due to it
It is possible to prevent the deterioration of the situation. Problems to be solved by the invention   However, subsequent studies have shown that such conventional control
It turns out that there are still problems with the method
Was. That is, the change in hydraulic oil capacity in the input-side variable pulley
Volume, input grooved variable pulley V groove width change stroke, etc.
Input that can be obtained correspondingly even if the manipulated variable is the same
The change in the shaft rotation speed or the change in the gear ratio is the actual gear ratio.
Although it is different in relation to
Constant neutral reference value regardless of the actual gear ratio of the transmission
Value is used, so that the entire gear ratio change range is
In some cases, good control characteristics could not be obtained.
For example, according to the starting operation of the vehicle, the throttle valve opening
Target input shaft rotation speed when increased to almost full open
The speed of the input shaft is increased rapidly.
Speed ratio with a rapid downshift to follow
But the deviation is close to the target input shaft rotation speed.
Overshoot even if switched to slow downshift
And then switched to a slow upshift to reach the target value
Even if you try to follow, the input shaft rotation speed
Increase in rotational speed due to engine output torque rather than lower amount
The amount is larger and the deviation from the target input shaft rotation speed is further expanded
Between a slow upshift and an intermediate speed upshift
It may exceed the first criterion value for switching.
In this way, when the deviation exceeds the first reference value, the intermediate speed
Degree upshift is started and the input shaft rotation speed and
Target torque when the output torque of the
Undershoot crossing the speed. And this
Repetition of input shaft rotation speed and transmission torque due to repetition
Fluctuations occurred, and drivability was sometimes impaired.
is there. Means to solve the problem   The present invention has been made in view of the above circumstances.
The main point is that the input and output shafts,
A pair of inputs on the input and output shafts
Variable pulley and variable output pulley, and variable input side
Transmission wound between pulley and output side variable pulley
Belt, the input-side variable pulley and the output-side variable pulley
Input-side hydraulic cylinder and V-groove width
And the output side hydraulic cylinder and the input side hydraulic cylinder.
The state in which the hydraulic oil flows in and the operation from the input side hydraulic cylinder
A shift direction switching valve that switches to a state in which oil flows out;
Hydraulic oil flowing into the input side hydraulic cylinder or its input
Restrict the flow rate of hydraulic oil flowing out of the power side hydraulic cylinder
In two positions: flow suppression state and unrestricted flow state
Bell with selectively controlled shifting speed control valve
G-type continuously variable transmission, the actual rotational speed of the input shaft
To the target rotation speed so that the shift direction switching valve
Control while upshifting or downshifting
The deviation between the actual rotation speed and the target rotation speed
When the shift speed control valve is within the first judgment reference value,
The state is switched to the flow suppression state, but the deviation is the first judgment reference value.
And the shift speed is not exceeded until the second reference value is reached.
A type in which the speed control valve is periodically switched between the two states.
Hydraulic control method for upshift or downshift
At the time of shift, the first judgment reference value is obtained in advance.
From the relationship, the higher the rotation speed of the input shaft, the larger
It is to change to become. The invention's effect   In this way, the upshift or downshift
The first criterion value at the time of
The higher the rotation speed of the input shaft becomes,
The actual input shaft rotation speed.
Intermediate speed shift and slow shift when following the rotational speed
Is properly switched in relation to the rotation speed of the input shaft.
Hunting and the resulting decrease in drivability are resolved.
Be erased. Example   Hereinafter, based on the drawings showing one application example of the present invention,
explain.   In FIG. 2, 10 is connected to the engine 8
The rotation of the engine 8 is shifted at a predetermined gear ratio to
Is a belt-type continuously variable transmission that transmits the output of
The hydraulic control device 12 for changing (shifting) the gear ratio
Have. On the other hand, the gear ratio controller 14
Torque sensor 16, primary variable pulley rotation sensor 18, secondary
Variable pulley rotation sensor 20, transaxle oil temperature sensor
From 22 etc., the throttle operation as the required engine load was
Throttle signal ST indicating the operation amount, of belt type continuously variable transmission 10
Rotation speed of primary variable pulley 24 (actual engine rotation speed
), The rotation speed of the secondary variable pulley 26
Rotation signal RO indicating the transaxle temperature
A signal TH is supplied. Gear ratio controller
14 is to grasp the operating state based on those signals
In particular, in order to obtain desired operating conditions mainly with the minimum fuel efficiency
The optimal target engine speed or target gear ratio
The actual engine speed or gear ratio and the target engine
Hydraulic pressure so that the rotation speed or target gear ratio matches.
The drive signals SD1 and S are supplied to the solenoid valves 28 and 30 in the control device 12.
Supply D2 respectively. Here, the belt type continuously variable transmission 10
The rotation speed of the primary (input) rotary shaft 32 is N_in,Secondary side
(Output side) Set the rotation speed of the rotation shaft 34 to N_outThen
Since the ratio γ is determined by the following equation, the actual vehicle speed
Relevant rotation speed N of the secondary rotation shaft 34_outAre common
From the target rotation speed N_in ^*And target gear ratio γ^*Is unique
Have a relationship. Therefore, the target rotation speed N_in ^*Real times
Rolling speed N_inSpeed ratio γ to match
And target gear ratio γ^*The actual gear ratio γ
Are substantially the same. γ = N_in/ N_out   The belt type continuously variable transmission 10 and the hydraulic control device 12 are
It is configured as shown in FIG. That is, the belt-type stepless
The transmission 10 has a primary rotation shaft 32 and a secondary rotation shaft.
The pair of primary (input) variable pulleys 24 and 34
And the secondary (output side) variable pulley 26
And a power transmission belt 36 wound around
The rotation transmitted from the engine to the primary rotation shaft 32
The force is transmitted to the secondary rotation shaft 34 via the transmission belt 36.
And the direction of rotation, including the gear train of the planetary gear unit, etc.
A differential gear (not shown) is connected via a gear 38 which can be converted.
Through the output shaft 40 connected to the wheels, etc.
ing. The primary variable pulley 24 is fixed to the primary rotation shaft 32.
Axial movement to the fixed rotating body 42 and the primary rotating shaft 32
Possible and non-rotatably fitted to the primary (input) hydraulic
Movable rotating body 46 that is moved in the axial direction by the Linda 44
Depending on the hydraulic pressure of the primary hydraulic cylinder 44
And a fixed rotating body 42 serving as a pair of pulley constituent members and a movable rotating body.
The width of the V-groove formed between the body 46 and the primary side
The effective diameter of the variable pulley 24 (the diameter of the transmission belt 36) has been changed.
It is supposed to be. Similarly, the secondary variable pulley 26
A fixed rotating body 48 fixed to the secondary rotating shaft 34 and its secondary
The secondary shaft is fitted to the shaft 34 so that it can move in the axial direction and cannot rotate.
Side (output side) hydraulic cylinder 50
The secondary hydraulic cylinder 50
According to the hydraulic pressure of the fixed rotating body
The groove width of the V groove formed between 48 and the movable rotating body 52 changes
The effective diameter is changed.
ing. The primary side oil as the first hydraulic cylinder
The pressure cylinder 44 has a double piston structure.
The secondary as the second hydraulic cylinder even if the in hydraulic pressure is supplied
Output larger than that of the side hydraulic cylinder 50 can be obtained.
ing.   The hydraulic control device 12 is supplied from the sensing valve 54.
Corresponding to the hydraulic signal and throttle valve opening
Oil pressure to generate hydraulic oil (line oil pressure) at a given pressure
Supply line hydraulic pressure to the device 56 and the primary hydraulic cylinder 44
Pressure from the primary hydraulic cylinder 44
By allowing the hydraulic oil to drain and reducing its pressure.
Shift direction to change the shift direction (change ratio of gear ratio)
Line supplied to the switching valve 58 and the primary hydraulic cylinder 44
Oil flow rate or flow rate discharged from primary hydraulic cylinder 44
Control to change the shift speed (speed ratio change speed)
A speed control valve 60 is provided, and a secondary hydraulic cylinder is provided.
Line 50 and sensing valve 54 are always supplied with line hydraulic pressure.
Is to be paid.   The hydraulic control device 12 will be further described with reference to FIG.
And the hydraulic pressure generating device 56 includes the pump device 62 and the regulator valve 6
4, throttle detection valve 66, lubricating oil cooler 68, cooler pressure
Consists of valve 70, etc., corresponding to throttle valve opening and gear ratio
Change the line pressure by changing the line pressure via the oil passage 72
Supply to valve 58, speed control valve 60, sensing valve 54, etc.
It is supposed to.   The sensing valve 54 has a spool valve 74 and one
Moves with the movable rotating body 46 of the secondary variable pulley 24 and
The biasing force corresponding to the gear ratio γ of the
Sensing piston applied to the spool valve 74 via the
And an input port 78 and an output port 80.
The flow area between them is controlled by the spool valve 74 which responds to the speed ratio.
The speed change shown in FIG.
The speed ratio pressure signal corresponding to the ratio γ
Power port 82 is provided.   The throttle valve 66 is provided with a spool valve 84 and a throttle valve.
Engages the cam 86 that rotates with the
By being moved with the operation, the spool valve
Apply spring force corresponding to the throttle valve opening to spring 88
And a piston 90 provided through the oil passage 72 and
Adjusting the flow area of the input port 92 which communicates, as shown in FIG.
Is done. A throttle pressure signal indicating the throttle valve opening is output.
Supplied from input port 94 to input port 96 of regulator valve 64
Is done.   The regulator valve 64 is provided with a spool valve 98 and the gear ratio.
Spool valve element receiving pressure signal and throttle pressure signal
And a valve plunger 100 for controlling the pump 98.
Connection between the line port 102 connected to the
By adjusting the distribution area of traffic,
The line oil pressure of the oil passage 72 communicating with the port 102 is shown in FIG.
Adjust so that That is, the output from the pump device 62
The hydraulic pressure supplied to the pump 106 is driven by the engine.
Power loss does not increase.
Slip on the transmission belt 36 of the belt-type continuously variable transmission 10
Is the minimum pressure required to prevent vehicle emissions
It is made to become. The pump device 62
Lube oil cooler 68, sensor
Sing valve 54, throttle detection valve 66, shift direction switching valve
58, operation returned to the tank 108 from the transmission speed control valve 60, etc.
Oil is pumped up by pump 106 and the hydraulic oil is
10 to the regulator valve 64 via the oil passage 112
Have paid.   The shift direction switching valve 58 and the shift speed control valve 60
Together, they constitute a shift valve device. Switching between these shifting directions
The valve 58 and the speed change control valve 60 are the first solenoid valve 28 and the
And the second solenoid valve 30 and the spool valves 118 and 120
And the line oil pressure is
Supplied to the first solenoid valve 28 and the second solenoid valve 30, respectively.
It is. The first solenoid valve 28 has a passage communicating with the oil passage 72.
An orifice 122 is provided and the first solenoid valve 28
By the closing operation (when not energized),
In the hydraulic pressure, the end face 12 of the spool valve element 124 of the spool valve element 118
When acted on 5, the spool valve 124
Group 126 is moved against the urging force of the solenoid 126.
Downstream from the orifice 122 by opening operation (excitation) of 8
By draining the oil side, the line to the spool valve 124 is
When the action of the hydraulic pressure is released, the spool valve 124
Can be moved according to the urging force of
I have. That is, the spool valve 124 operates as the first solenoid valve 28.
In two positions, a supply position and a discharge position, in response to movement
At the supply position (spring 126 side)
In addition, while the oil line 72 and the supply line 128 are connected,
The line between the line 130 and the drain line 131 is cut off,
Allow supply of line hydraulic pressure to the secondary hydraulic cylinder 44
Supply state, and the other side, that is, the discharge position.
In other words, the communication between the oil passage 72 and the supply line 128 is interrupted.
The discharge line 130 is opened to the drain line 131,
Discharge state that allows hydraulic oil to be discharged from the side hydraulic cylinder 44
You get the condition.   On the other hand, the second solenoid valve 30 also has an orifice 132
When the valve is closed, as in the case of the first solenoid valve 28, the spool
The orifice 132 is attached to the end face 135 of the spool 134 of the valve 120.
The applied line oil pressure is applied, and the spool valve 134
It is moved against the urging force of the spring 136.
Release the line hydraulic pressure on the spool valve 134.
Is released and the spool valve 134 biases the spring 136
Moved according to the force. Primary spool valve 120
Output port 138 and input communicating with side hydraulic cylinder 44
A port 140 is provided and the supply line 128 and
Supply port 142 and discharge port 130 respectively connected to
Discharge line 144 and the discharge line 13 through the orifice 146.
And a deceleration port 148 connected to the
The spool valve is opened by the closing operation (when not energized) of the solenoid valve 30.
When the 134 is positioned on the spring 136 side, the input port
While the connection between port 140 and deceleration port 148 is cut off,
When the communication between the port 140 and the discharge port 144 is made
In addition, spool between output port 138 and supply port 142
Communicated through an orifice 150 formed in the valve 134
You. Further, according to the opening operation of the second solenoid valve 30 (at the time of excitation),
The spool valve 134 is moved according to the spring 136.
Between the output port 138 and the supply port 142, and
Communication between input port 140 and deceleration port 148 is established
With the input port 140 and the discharge port 144
It is supposed to be.   That is, the spool valve element 134 of the shift speed control valve 60 is
Based on the operation of the second solenoid valve 30 functioning as a pilot valve
Of the hydraulic oil flowing from the supply line 128 to the output port 138.
2nd position: throttle position where flow is suppressed and open position where flow is not suppressed
At the same time as
If the two positions are for the discharge system, the input port 140
Without restricting the flow of hydraulic oil from
Corresponds to two positions: release position and throttle position
However, in this application example, one shift speed control valve 60 is supplied.
It is common to the system and the discharge system. Soshi
When the shift direction switching valve 58 is in the supply state,
Either the throttled state or the open state for the supply of
When in the discharge state, the discharge
State or open state is controlled by the shift speed control valve 60.
Selected, based on the increase or decrease in the effective diameter of the primary variable pulley 24
Therefore, when the gear ratio is increased or decreased,
The shift speed in both cases is controlled. This change
The speed control valve 60 is turned ON / OFF via the second solenoid valve 30
The operation of the solenoid valve 30 is controlled by the
Is controlled by the controller 14.   As described above, the controller 14
Xel operation amount, that is, a throttle that indicates the throttle valve opening θ
The throttle signal ST is supplied and the throttle operation amount (
In other words, based on the engine load,
Of the primary rotation shaft 32 to obtain the driving performance required
Target rotation speed N_in ^*Is determined. To controller 14
Is, for example, as shown in FIG.
Operating the engine 8 exclusively on the minimum fuel efficiency in accordance with the degree θ
Target rotation speed N_in ^*Or a function expression that gives
A conversion table is stored, and a relation determined in advance in such a manner is stored.
The target engine based on the actual throttle signal ST.
Rotation speed N_in ^*Is determined. In addition,
The rotation signal RI of the primary variable pulley 24 is input to the roller 14.
The actual rotation speed N of the primary rotation shaft 32 is_in
Is supplied, and the controller 14 determines its actual rotational speed N._in
And the target rotation speed N determined as described above._in ^*Compare with
And the deviation Δn_in(= N_in ^*-N_in) To calculate the bias
A difference calculation means is provided.   The controller 14 calculates the deviation Δn_inIs within the specified range
During a certain time, a pulsed drive current is supplied to the second solenoid valve 30
To turn ON / OFF the second solenoid valve 30
Deviation Δn_inOf the pulsed drive current according to the magnitude of
By changing the duty ratio, the excitation time of the second solenoid valve 30 and the
Drive control means for changing each time ratio with the magnetic time
Contains. Based on that, before the shift speed control valve 60
The time ratio between the two states of the contracted state and the open state is
Difference Δn_inOf the transmission ratio of the continuously variable transmission 10
Is controlled to be smaller. Note that the above
To change the duty ratio of the loose drive current,
The wave number, that is, the period may be constant and the pulse width may be changed,
The pulse width may be constant and the period may be changed.   Further, the controller 14 calculates the deviation Δn_inIs given
1 Judgment standard value A_1UOr A_1DIf it is within the second
Position the solenoid valve 30 on the side that suppresses the flow rate in the two positions.
To stabilize gear ratio control. At this time, the first judgment
Value A at the time of quasi-value upshift_1UIs the rotation of the primary rotation shaft 32
Speed N_inIt can be changed in connection with.   Next, the operation of the hydraulic control device configured as above
FIG. 9 shows an example of application of the method according to the present invention.
This will be described with reference to a flowchart.   First, in step S1, the controller 14
Torque signal ST and the rotation signal R1 of the primary variable pulley 24
Of the throttle valve opening θ and the rotation of the primary rotation shaft 32.
Rotation speed N_inRead. And in step S2
Target rotational speed N corresponding to throttle valve opening θ_in ^*Is decided
And at step S3 the target rotational speed N_in ^*When
Actual rotation speed N_inDeviation Δn_inIs calculated. Soshi
In step S4, the first determination reference value A at the time of the upshift
_1UA determination reference value determination routine for determining
After that, in step S5, the deviation Δn_inIs a neutral criterion
Reference value A₀Greater or neutral criterion value -A₀Less than
The decision is made. This neutral judgment reference value A₀Is near zero
Is a very small value, and the upshift and downshift
A hysteresis is provided between them.
No problem.   In the determination reference value determination routine, as shown in FIG.
First, in step SS1, the actual rotational speed N_inBut
Predetermined reference rotation speed N_in1Whether or not
Is determined. If this judgment is affirmed, step
The first determination criterion value A at the time of upshift by executing the shift SS2
_IUIs the value A_AIs determined, but if denied,
SS3 is executed. In this step SS3, the actual rotation
Speed N_inIs a predetermined reference rotation speed N_in2Less than
Is determined. If this judgment is affirmed
The step SS4 is executed and the first criterion value A_1UIs the value
A_BIf not, step SS5
Executed first criterion value A_1UIs the value A_CIs determined.
Here, the first determination reference value A at the time of the upshift is described._1Uage
Each value adopted is A_C> A_B> A_ARelationship
In addition, the judgment reference rotation speed is N_in2> N_in1In the relationship
You. That is, the first judgment reference value A_1UIs the primary rotation shaft 32
Rotation speed N_inIs calculated in advance as shown in FIG.
Are in a certain relationship.   Returning to FIG. 9, in step S5, Δn_in<-
A₀The state that is determined to be
That is, the actual rotation speed N of the primary rotation shaft 32_inIs the target rotation
Speed N_in ^*Lower than the gear ratio γ.
Actual rotation by performing upshift to reduce
Speed N_inNeed to be reduced. That is, Δn_in<-
A₀In the case of, as shown in step S6, the first solenoid valve 2
Drive signal SD1 is not supplied to 8, it is turned off
As a result, the spool valve element 124 of the spool valve element 118
The line is moved to the supply position as shown
The oil passes through the spool valve 118, the supply line 128, and the spool valve 120.
Supply state to supply to the primary side hydraulic cylinder 44,
The movable rotator 46 of the primary side variable pulley 24 faces the fixed rotator 42
Upshift to move and expand its effective diameter
It is chosen. On the other hand, Δn_in> A₀In Case of,
Conversely, a downshift that increases the gear ratio γ is selected.
Selected. That is, as shown in step S7, the solenoid valve
28 when the drive signal SD1 is supplied and turned on.
With this, the spool valve 124 is moved to the discharge position.
The discharge line 130 is opened to the drain line 131,
Allows hydraulic oil to be discharged from the primary hydraulic cylinder 44 side
And the movable rotation of the primary side variable pulley 24
The body 46 is separated from the fixed rotating body 42 to reduce its effective diameter
It is a downshift that can be done.   And the above-mentioned deviation Δn_in(= N_in ^*-N_inAbsolute)
Value | Δn_inThe speed of change of the gear ratio γ in relation to the magnitude of |
As shown in Fig. 11 during the upshift,
As shown in FIG._2UAnd the first judgment reference value A_1U
Is set during the downshift, as shown in Fig. 12.
Sea urchin second criterion value A_2DAnd the first judgment reference value A_1DIs set
And each is provided in the controller 14.
You. A above_1UExcept for the reference value A_2U, A_2D, And A_1D
Is a constant value, and in general, A_2U≧ A_1UAnd A_2D≧ A
_1DAnd A_1D≧ A_1UThere is a relationship. Accordingly
And the deviation Δn_inAre H, I, J during upshift
In the range of
In the range of K, L or M.   By executing step S6, the shift direction switching valve 58 is
Above (in the state of hydraulic oil supply)
Absolute value of deviation | Δn_inHow large is |
To make a determination, first, | Δn_in| Is the standard
Value A_2UIs determined. | Δn_in|
> A_2UIf it is determined in step S9 that the second solenoid valve
The drive signal SD2 is supplied to 30 and it is turned on.
This state corresponds to a drive state with a duty ratio of 100%.
You.   When the second solenoid valve 30 is turned on (excited), the oil passage 72
Line oil passes through the spool valve 118 in the supply state,
It flows directly from the supply line 128 to the output port 138,
It is rapidly supplied to the side hydraulic cylinder 44. Supply at this time
The oil quantity is Q as shown in Fig. 13.₁And by its supply
The effective diameter of the primary variable pulley 24 is rapidly increased,
High shift speed during gear shift (speed ratio change speed)
Is obtained.   On the other hand, in step S8, | Δn_in|> A_2UNot
(Not in the range of J), go to step S10
And | Δn_in| Is A whose value was determined in step S4
_1UWhether it is less than, that is, in the range of H
Is determined. | Δn_in| ≦ A_1UIf it is determined that
In step S11, the drive signal SD2 is supplied to the second solenoid valve 30.
The second solenoid valve 30 is turned off (demagnetized). This OFF
The state is a driving state with a duty ratio of 0%.   If the second solenoid valve 30 is turned off, the spool valve 134
Is in the state shown in FIG. 4 and has passed through the spool valve 118.
Line oil from oil line 72 is primary through orifice 150
This is supplied to the side hydraulic cylinder 44. This drawing
In the state, as shown in FIG._TwoIn
As a result, the effective diameter of the primary side variable pulley
The low shift speed at the time of upshift is increased
can get.   On the other hand, in step S5, it is determined that the vehicle is in the downshift state.
If it has been disconnected, in step S7 the shift direction switching valve
58 is a downshift (discharge state). In this case
The first reference value A at the time of the shift upshift_1UYou
And second criterion value A_2UIs the first reference value during downshifting
A_1DAnd the second criterion value A_2DIs only changed to
The same is true. That is, in step S12, | Δn_in|
> A_2DIs determined in step S13, the second solenoid valve 30
Is set to the OFF state and the high shift in the downshift direction is
Shift speed is obtained. In step S13, | Δ
n_in| ≦ A_1DIf it is determined that the
In 5, the second solenoid valve 30 is turned on and the downshift
Is performed at a low shift speed. Where
FIG. 14 shows the second electromagnetic in the downshift state as described above.
Operating state of valve 30 and oil spillage from primary hydraulic cylinder 44
And the relationship between_ThreeIs the maximum flow rate, Q_FourIs the minimum flow
Indicates the amount.   Deviation | Δn during upshift_in| Is the first criterion
Reference value A_1UAnd the second criterion value A_2UBetween and
| Δn during downshift_in| Is the first judgment reference value
A_1DAnd the second criterion value A_2DIf it is between
In the case of being in the I region and the L region in FIGS. 11 and 12.
, The duty control is executed. In such a case
Sets the duty ratio to the deviation | Δn_inAccording to |
First, in step S16, the deviation
| Δn_in| Is decreasing or increasing
Is determined. That is, the most recently calculated deviation | Δn
_in| And the deviation | Δn calculated in the previous cycle_in'|
It is determined whether the difference from is positive or negative.
If it is determined to be positive, the deviation | Δn_in| Is in the process of decreasing
Therefore, the du to be determined in step S17
Tea ratio D₁From the previous cycle duty ratio D '
An operation to reduce by ΔD is executed and the duty ratio is determined.
Is determined. On the other hand, if it is determined to be negative, the deviation | Δn
_in| Tends to increase, in which case
Duty ratio D to be determined₁The previous duty ratio
Step S18 for increasing D 'by ΔD is executed.
Thus, the duty ratio D is determined.   Note that the duty ratio D₁To determine
For example, the basic equation shown in the following equation (1) is stored in the controller 14 in advance.
Remembered. D₁= ｛(1 / B) × | N_in ^*-N_in｜ + C｝ × 100                                       ... (1) Where B and C are constants   Now, B = 1000, C = 0.3, A_2D= 300, A_1D= 50
| N_in ^*-N_inOperation formula (1) is executed when | = 300
And the duty ratio D at that time₁Is 60%.   Duty ratio D during upshift₁Is the above
As determined in steps S16, S17 and S18
However, during the downshift, the ON / OF of the second solenoid valve 30
Upshift from F to F / S
Since the time is reversed, in step S19,
Duty ratio D₁Is the determined value
It is Δn_inJudgment by positive or negative
Is done. Δn_inIf <0, it is an upshift state
Therefore, the above D₁Is output as the duty ratio as it is
But Δn_inIf> 0, it is downshift state
In step S20, the following equation (2) D_Two= ｛1- (D₁/ 100)｝ × 100 ・ ・ ・ (2) Is executed, and the duty ratio D obtained as a result is obtained._TwoBut,
It is output as a determined value in the case of a downshift. What
Incidentally, if it is made to correspond to the above equation (1), D_TwoFor seeking
As an arithmetic expression, for example, the following expression (3): D_Two= [1-｛(1 / B) × | N_in ^*-N_in| + C｝] × 100                                       ... (3) In any case, D_TwoBut
If 40%, then D₁Is 60%.   Thus, in steps S19 and S20, finally
Duty ratio D₁Or D_TwoIs determined, such a du
Tea ratio D₁Or D_TwoOf the pulse-shaped drive current
In S21, the power is supplied to the second solenoid valve 30, and the operation is repeated.
ON / OFF drive. Then, in step S22,
Duty ratio D obtained through the above steps
₁For the next duty ratio.
Is read as the duty ratio D '. And the above series
Are repeatedly performed.   Due to the above duty control, during upshift
At the time of the downshift, the actual rotational speed N
_inIs the target rotation speed N_in ^*Closer to
Overshoot and hunting
Good gear ratio control responsiveness without
To achieve such fine-grained responsiveness
Need not use a proportional flow control valve such as a servo valve.
In the case of control characteristics caused by valve sticks, etc.
It also leads to preventing flicker.   Also, the gear ratio γ of the belt-type continuously variable transmission 10 as described above.
The first determination reference value A at the time of the upshift_1U
Is the rotation speed of the engine 8, that is, the rotation of the primary rotation shaft 32.
Rolling speed N_inWill be changed in relation to
The problem is solved. That is, the first judgment reference value A_1UBut one
In the case of the conventional case where it is set to a fixed value, it is shown in FIG.
Time t₀Access Vedal at Throttle
When the valve is depressed to a substantially fully open position and the target rotation speed N_in ^*But
When the vehicle starts up, the target rotation speed N_in ^*To follow
First, the first solenoid valve 28 is turned on and the second solenoid valve 30 is turned on.
The state is turned off, and a rapid downshift is performed. What
At the beginning of the vehicle start, a start control routine (not shown)
Is executed, the time t₁Until the time elapses
When the magnetic valve 30 is turned on and a slow downshift is performed,
The transmission belt 36 is prevented from slipping when traveling
Has become. At such a start, the target rotation speed N
_in ^*To the actual rotational speed N_inApproaches, time t_TwoAnd time
t_ThreeAnd the deviation | Δn_in| Is the second size
Disconnection reference value A_2DThe duty system of the second solenoid valve 30 becomes
Control is started, downshifting to intermediate speed, and then
Time t_ThreeAnd time t_FourAnd the deviation | Δn_in|
Is the first criterion value A_1DThe second solenoid valve 30 is ON as below
And a slow downshift takes place. Time t_Four
Is the actual rotation speed N_inIs the target rotation speed N_in ^*Neutral judgment
Reference value A₀It shows the state that exceeded just. And even more
As the amount of shoot increases, the first
The solenoid valve 28 and the second solenoid valve 30 are both turned off and delayed.
Upshift is started. But such a launch
In this case, since the throttle valve is fully opened,
Effect of lowering the rotation speed of primary rotating shaft 32
Effect of increasing the rotation speed by the output torque of the engine 8
Is larger, and the amount of overshoot increases,
Difference | Δn_in| Is the first criterion value A for upshifting_1UTo
To reach. Time t in FIG._FiveIndicates this state. to this
Belt type stepless with upshift of intermediate speed started
The speed of change of the speed ratio γ of the transmission 10 increases sharply,
Rolling speed N_inSharply decreases and the output torque decreases. Ma
The actual rotational speed N_inIs the target rotation speed N_in
^*Once, but the same phenomenon as above occurs and
A speed upshift is performed temporarily. Time in Fig. 16
t₆Indicates this state. In this way, when the vehicle starts
Output torque fluctuates and the drivability is impaired.
In some cases.   However, according to the present embodiment, the first format at the time of the upshift is used.
Disconnection reference value A_1UIs the rotational speed of the engine 8, that is, the primary side
Rotation speed N of input shaft 32_inChanges to a large value as the
Therefore, as shown in FIG._FourFrom time t_Five
Deviation | Δn even during the overshoot period leading to_in| Is the first size
Disconnection reference value A_1UWithout exceeding the conventional case described above.
As described above, the output torque fluctuates and drivability is impaired due to this.
The harm is eliminated.   As described above, one application example of the present invention has been described based on the drawings.
However, the present invention is applied in other aspects.   For example, in the above application example, the first
Judgment reference value A_1UAre based on a step-by-step relationship as shown in Figure 10.
It is determined based on, for example, as shown in FIG.
Can be determined based on a linear relationship
It is.   Further, in the above application example, the first shift at the time of the upshift is performed.
Judgment reference value A_1UDecision criterion decision route for deciding
Is provided between step S8 and step S10 in FIG.
It can be done.   Further, in the above application example, the first determination at the time of the upshift is performed.
Reference value A_1UAnd first judgment reference value A at the time of downshift_1DAnd
Though considered separately, common values may be used
It is. In such a case, the criteria
Between step S12 and step S14 in FIG.
Can be provided.   In addition, the present invention does not depart from the spirit of the present invention.
Various changes, improvements, combinations, etc. based on the knowledge of those skilled in the art
Needless to say, the present invention can be applied in a mode in which
You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a main part of the flowchart of FIG. 9, showing an example of application of the method of the present invention, and FIG. 2 is a belt type to which the present invention is applied. It is a figure showing an outline of an example of a continuously variable transmission. FIG. 3 is a diagram showing a configuration of a main part of FIG. FIG. 4 is a cross-sectional view of a main part for describing the configuration of the hydraulic control device of FIGS. 2 and 3 in further detail. Fifth
The figure shows the relationship between the speed ratio pressure signal output from the sensing valve of FIG. 4 and the amount of movement of the movable rotator. FIG. 6 is a diagram showing the relationship between the throttle pressure signal output from the throttle valve of FIG. 4 and the throttle valve opening. FIG. 7 is a diagram showing the relationship between the line oil pressure adjusted by the regulator valve of FIG. 4 and the throttle valve opening. FIG. 8 is an example of a graph for giving a target engine rotational speed corresponding to the throttle valve opening, and FIG. 9 is a flowchart for explaining the operation in one application example of the present invention. FIG. 10 is a diagram showing the relationship used in the flowchart of FIG. FIG. 11 and FIG.
FIG. 12 is an explanatory diagram for explaining a pattern in which the magnitude of the deviation between the target rotational speed and the actual rotational speed in the example of FIG. 9 is classified. FIGS. 13 and 14 are diagrams showing the change characteristics of the supply flow rate and the discharge flow rate with respect to the duty ratio of the signal for driving the solenoid valve in the shift speed control valve device of FIG. 4, respectively. FIG. 15 is a timing chart showing the operation described in FIG. FIG. 16 is a diagram corresponding to FIG. 15 showing a conventional case. FIG. 17 is a diagram corresponding to FIG. 10 in another application example of the present invention. 10: Belt type continuously variable transmission 24: Primary side variable pulley (input side variable pulley) 26: Secondary side variable pulley (output side variable pulley) 32: Primary side rotary shaft (input shaft) 34: Secondary side rotary shaft (Output shaft) 36: Power transmission belt 44: Primary hydraulic cylinder (input hydraulic cylinder) 50: Secondary hydraulic cylinder (output hydraulic cylinder) 58: Shift direction switching valve 60: Shift speed control valve N _in ^* : Target Rotation speed A _1U : 1st criterion value

Claims (1)

(57) [Claims] An input shaft and an output shaft, a pair of input-side variable pulleys and an output-side variable pulley provided on the input shaft and the output shaft, and a transmission belt wound around the input-side variable pulley and the output-side variable pulley; An input-side hydraulic cylinder and an output-side hydraulic cylinder for respectively changing the V-groove width of the input-side variable pulley and the output-side variable pulley; a state in which hydraulic oil flows into the input-side hydraulic cylinder; A shift direction switching valve for switching between a flow-out state and a flow-out state, and a flow restriction state in which the flow rate of hydraulic oil flowing into the input-side hydraulic cylinder or hydraulic oil flowing out from the input-side hydraulic cylinder is restricted, and a flow-rate non-restriction state in which no restriction is made. A belt-type continuously variable transmission having a transmission speed control valve selectively switched to two positions, The shift direction switching valve is controlled so as to coincide with the rotation speed, and when the deviation between the actual rotation speed and the target rotation speed is within a predetermined first determination reference value during an upshift or a downshift. Switches the shift speed control valve to the flow suppression state, and periodically switches the shift speed control valve between the two positions until the deviation exceeds the first reference value and before reaching the second reference value. A hydraulic control method of controlling the flow rate at an intermediate speed by switching to the first mode during an upshift or a downshift.
A hydraulic control method for a belt-type continuously variable transmission, wherein a judgment reference value is changed from a relationship obtained in advance so as to increase as the rotation speed of the input shaft increases.