JP2002005278A - Variable speed control device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable speed control device for a continuously variable transmission capable of kicking down to set a final target change gear ratio at a change gear ratio which lowers at less speed when the target change gear ratio of the variable gear change lowers at a speed higher than the specified one on reaccelerating. SOLUTION: In the case that a throttle opening θt at a preceding sampling period TPSn-1 is 0% and an engine brake is in an operating state through judging from a step 5, when a deviation of a target change gear ratio ΔT(=|Tn-1-Tn|) at the present and preceding sampling periods comparing with a step 6 exceeds a threshold Y, the change gear ratio reduced from the preceding target change gear ratio Tn-1 by a determined amount T is set at the present final target change gear ratio Tnf in a sep 7 to gain smooth kicking down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a continuously variable transmission that controls a shift operation of a continuously variable transmission based on shift information such as a vehicle speed and an accelerator operation amount of an engine.

[0002]

2. Description of the Related Art Conventionally, as an example of a continuously variable transmission having a large transmission torque, there is a toroidal type continuously variable transmission as shown in FIG. FIG. 7 is a schematic view showing a cross section of a part of a toroidal type continuously variable transmission mounted on a vehicle. The toroidal type continuously variable transmission 1 generally includes an input shaft 2 to which an output of the engine E is input, a main shaft 3 which is arranged coaxially with the input shaft 2, and outputs rotation after shifting, and is rotatable with respect to the main shaft 3. A supported input disk 4, an output disk 5 arranged opposite to the input disk 4 and fixed to the main shaft 3, arranged between the input disk 4 and the output disk 5 and from the input disk 4 to the output disk 5 A pair of tiltable power rollers 6 for transmitting torque, and a pair of flange portions 7 provided on the input shaft 2 and the input disk 4 are arranged between the input disk 4 and act on the input disk 4 to reduce the magnitude of the input torque. A pressing means 8 such as a loading cam for changing the pressure contact force of the power roller 6 according to the rotation of the input disk 4 according to the tilt angle by tilting the power roller 6 is provided. Shift to be transmitted to the stepless output disk 5.

[0003] The input disk 4 and the output disk 5 have toroidal curved surfaces that frictionally engage with the power roller 6. The rotation between the input disk 4 and the output disk 5
The power is transmitted via the power roller 6 based on the shearing force of the oil. When the power roller 6 tilts as indicated by the angle θ in the drawing, the contact position of the power roller 6 with the input disk 4 becomes the position of the radius r ₁ , and the contact position of the power roller 6 on the output disk 5 becomes the position of the radius r _2. the gear ratio between the output disc becomes r ₂ / r _1. The power roller 6 is rotatably supported around its own rotation axis 10 by a tiltable trunnion 9, and tilts about a tilt axis 11 (perpendicular to the paper plane) perpendicular to the rotation axis 10. It is possible.

In the conventional control of a continuously variable transmission, in general, speed change information such as a vehicle speed and an accelerator operation amount is detected by various sensors which are detection means, and a target speed ratio calculation means uses a detected value of the speed information as a parameter. The target speed ratio is calculated on the basis of the speed change map described above, and the target speed ratio is made to coincide with the actual speed ratio.

In the shift map control described above, for example, when the throttle opening is used as the accelerator operation amount, if the throttle opening is 0%, the engine brake is applied by simply changing the target gear ratio. Then, the speed ratio control based on the speed change map is as follows. That is, when the throttle opening is greater than 0%, at the same vehicle speed, it is determined that the load is greater as the accelerator is depressed more and the throttle opening is larger, and the gear ratio is increased to shift down to the deceleration side to reduce the load. Shift control is performed so that the vehicle travels at the shift speed. In other words, when a> b, the gear ratio of the throttle opening a%> throttle opening b%
Gear ratio. When the throttle opening is 0%, the throttle opening is always 0% at the same vehicle speed so that the engine brake works in a certain vehicle speed range.
Is set to be larger than the speed ratios of the other throttle openings.

FIG. 6 is a shift map showing the relationship between the vehicle speed V and the throttle opening θ _t (load) in the case of a stepped transmission. As shown in FIG. 6, in the vehicle speed V _0, the speed ratio e in the region throttle opening theta _t is close to 0 A is a large value at 1st (first speed), the throttle opening theta _t is from around 0 As the speed ratio increases, the speed ratio e becomes 3rd (third speed) in the region B, 2nd (second speed) in the region C, and 1st in the region D.
(First speed). When an operation to temporarily returning the accelerator pedal by the vehicle speed V ₀ the throttle opening theta _t a sharp 0% next engine braking. Immediately after that, to perform a kick-down operation, if the accelerator pedal is depressed again to perform rapid acceleration, once in the area B according to the shift map,
After shifting up to rd, the process shifts to region C or region D. Therefore, in the area B, the vehicle is once in a stall state and then accelerates. It is clear that the same phenomenon occurs in the case of the continuously variable transmission as in the case of the stepped transmission.

FIG. 5 is a graph showing the lapse of time between the gear ratio and the throttle opening in the conventional shift control of the continuously variable transmission, and illustrates the situation of the kick down operation.
As shown in FIG. 5, increasing the throttle opening theta _t to 50% of a high gear ratio state (deceleration side), the gear ratio gradually decreases (shifts to the acceleration side) in response to an increase in vehicle speed . By suddenly reducing the throttle opening theta _t 0% by releasing the accelerator depression, then it assumed that reacceleration to kick down. Since decreasing the throttle opening theta _t 0% engine brake begins to work, the gear ratio is slightly increased (downshifting) by the operation of shift control device in response to a decrease in the vehicle speed. Greatly increasing the throttle opening theta _t depresses larger the accelerator immediately thereafter (in the graph 90
%) And the gear ratio slightly decreases (shifts up),
Some sense of stall occurs. After that, the gear ratio starts to increase (shift to the deceleration side), and a large torque is obtained to kick down.

In regard to the shift control of the continuously variable transmission for a vehicle, when the braking state detecting means for detecting the braking state of the vehicle detects the braking ON state, the continuously variable transmission is prohibited from shifting to the speed increasing side. By doing so, it is possible to apply the engine brake and release the brake pedal from the control state to shift to the acceleration state, that is, to shorten the kick down time when performing the kick down operation and respond It has been proposed to improve the performance (Japanese Unexamined Patent Publication No.
194,941).

[0009]

Therefore, when the vehicle driver attempts to re-accelerate the vehicle, the change in the gear ratio in the upshift direction, which causes a sense of stall, is reduced or slightly stopped. However, there is a problem to be solved in that the gear ratio is changed in the direction of quickly downshifting.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and when the accelerator operation is rapidly increased from a zero operation amount, a change in a gear ratio in a shift-up direction is reduced or minutely changed. The shift control device of the continuously variable transmission that enables a quick re-acceleration of the vehicle by stopping, thereby quickly downshifting the gear ratio, reducing the sense of stall, or obtaining a kickdown with good response without causing a sense of stall. It is to provide.

According to the present invention, there is provided a detecting means for detecting shift information such as a vehicle speed and an accelerator operation amount of an engine, and a detecting means provided at a subsequent stage of the engine in accordance with the shift information detected by the detecting means at each sampling time. Target speed ratio calculating means for calculating the target speed ratio of the stepped transmission, accelerator operation determining means for determining the presence or absence of an accelerator operation, the previous target speed ratio calculated by the target speed ratio calculating means at the previous and current sampling times, and the current Threshold value comparing means for comparing whether the target gear ratio deviation obtained from the target gear ratio is greater than a predetermined threshold value, and the accelerator operation amount at the previous sampling time by the accelerator operation determining means is equal to or less than a predetermined value. Is determined and the target speed ratio deviation fluctuates beyond the threshold in the comparison by the threshold comparing means. In response, the present invention relates to a shift control device for a continuously variable transmission, comprising target speed ratio setting means for setting a speed ratio changed from the previous target speed ratio by a predetermined amount smaller than the target speed ratio deviation to a current final target speed ratio. .

In the shift control device of the continuously variable transmission, for example, during a kick-down operation, that is, the accelerator operation amount is temporarily reduced to zero (a predetermined value or less) to set the operation state of the engine to the engine brake state. When trying to accelerate the vehicle suddenly by increasing the accelerator operation amount,
The target gear ratio calculating means calculates a target gear ratio that temporarily fluctuates to a speed increasing side in response to a large accelerator operation amount. By comparing the threshold value comparing means, it is determined that the target gear ratio deviation, which is the difference between the previous target gear ratio and the current target gear ratio, fluctuates more than a predetermined threshold, and the accelerator operation is started at the start of the kick-down operation. Since the amount is once set to zero and there is no accelerator operation at the previous sampling time, the target gear ratio setting means sets the current target gear ratio to
Instead of following the target gear ratio obtained from the gear ratio map, the gear ratio is set to a value that is changed from the previous target gear ratio by a predetermined amount smaller than the target gear ratio deviation. Therefore, the amount of change in the gear ratio that temporarily shifts to the upshift side is reduced or reduced to a small amount, and kick-down acceleration becomes possible immediately.

In the shift control device for a continuously variable transmission,
The threshold value comparing means determines the absolute value of the difference between the previous target gear ratio and the present target gear ratio as the target gear ratio deviation. Since the target gear ratio deviation is the absolute value of the difference, the target gear ratio deviation Is applicable to both the speed increasing side and the decelerating side. The target gear ratio setting means has a value smaller than the threshold value as the predetermined amount. When the target gear ratio deviation is larger than the threshold value, the gear ratio control according to the present invention is executed, so that the control can be performed in small gear ratio steps with a predetermined amount smaller than the threshold value.

In the shift control device for a continuously variable transmission,
The threshold value comparing means sets a target gear ratio deviation as an absolute value of a difference between the previous target gear ratio and the current target gear ratio as the target gear ratio deviation.
A first threshold for comparing the target gear ratio deviation and a second threshold larger than the first threshold and corresponding to rapid acceleration are defined. When the threshold is the first threshold, control corresponding to the case of relatively gentle acceleration is performed as in the case described above. When the threshold is the second threshold, control corresponding to the case of sudden acceleration is performed. The target gear ratio setting means includes, as the predetermined amount, a first predetermined amount having a value smaller than the first threshold and a second predetermined amount having a value smaller than the second threshold and smaller than the first predetermined amount. And When the target gear ratio deviation is larger than the threshold value, the gear ratio control according to the present invention is executed, so that a predetermined amount smaller than the threshold value enables control in small gear ratio increments, and in the case of sudden acceleration. With the second predetermined amount smaller than the first predetermined amount, finer gear ratio control is executed.

The shift control device for a continuously variable transmission includes braking state determining means for determining a braking state of the vehicle. When the braking state determining means determines that the braking state is off, The accelerator operation determining means determines whether or not the accelerator operation has been performed at the previous sampling time, and the accelerator operation determining means determines that the accelerator operation amount exceeds a predetermined value. Is determined to be ON, the target gear ratio setting means sets the target gear ratio calculated by the target gear ratio calculating means at this sampling time as it is as the final target gear ratio this time. When the braking state determining means determines that the braking state is on, and even when the braking state determining means determines that the braking state is off, the accelerator operation determining means determines that the accelerator operation amount at the previous sampling time is a predetermined value. If it is determined that the kick-down operation is performed, the target gear ratio calculated by the target gear ratio calculation means at the current sampling time is not performed without performing the gear ratio control assuming the kick-down operation. The ratio is directly set to the final target gear ratio this time.

The continuously variable transmission is a toroidal type continuously variable transmission. In a continuously variable transmission such as a toroidal-type continuously variable transmission, if a gear is shifted at a relatively slow speed as determined by a shift map during braking, for example, when an engine brake is applied on an uphill slope When the vehicle decelerates relatively quickly, the actual speed change cannot catch up with the changing target gear ratio, and if the engine stalls or the vehicle stops, the vehicle will start next. The shift to the starting gear ratio becomes impossible. By applying the shift control device according to the present invention to a toroidal-type continuously variable transmission, the gear ratio changes quickly even during deceleration, avoiding the above-mentioned disadvantages, and even during re-acceleration, kickdown can be performed without feeling of stall due to shift-up. It is possible to obtain.

According to the present invention, there is provided a continuously variable shift calculated based on shift information such as a vehicle speed and an accelerator operation amount, even when an operation amount of the vehicle is rapidly increasing from an zero operation amount. In response to the state in which the target gear ratio of the machine is shifting to the speed increasing side with a gear ratio width equal to or greater than a certain
The present invention relates to a speed change control device for a continuously variable transmission, comprising setting a speed ratio decreasing at a speed ratio width smaller than the predetermined speed ratio width as a final target speed ratio. That is, if the target gear ratio is still decreasing at a certain rate or more while trying to accelerate suddenly, a stall feeling is felt by upshifting. To avoid this, the final target gear ratio is set as By setting a gear ratio that decreases at a small rate, upshifts can be reduced or suppressed to a small amount, and quick kickdown can be performed. The driving state of the vehicle includes that the braking operation state of the vehicle is off, and in this case, the braking operation is off and the accelerator operation amount is zero. Quick transition is possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a shift control device for a continuously variable transmission according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing an outline of a shift control device for a continuously variable transmission according to the present invention, FIG. 2 is a flowchart showing an example of a shift control flow by a shift control device for a continuously variable transmission according to the present invention, and FIG. FIG. 4 is a flowchart showing another example of a shift control flow by the shift control device of the continuously variable transmission according to the present invention. FIG. 4 is a graph showing the elapsed time of the gear ratio and the accelerator operation amount controlled by the shift control device of the continuously variable transmission shown in FIG. It is a graph shown.

FIG. 1 is a block diagram showing an outline of a shift control device for a continuously variable transmission according to the present invention. According to FIG. 1, a detecting means 20 comprising various sensors installed in a vehicle
Shift information is input to the target speed ratio calculating means 21, the target speed ratio calculating means 21 target speed ratio T (previous target in each control cycle, such as but throttle opening theta _t as the vehicle speed V and the accelerator operation amount detected The gear ratio T _n-1 and the current target gear ratio T _n ) are calculated. Based on the target gear ratio T calculated by the target gear ratio calculator 21 (the previous target gear ratio T _n-1 and the current target gear ratio T _n ), the threshold comparing unit 22 compares the previous target gear ratio T _{n -1} with the current gear ratio T _{n -1.} a target gear ratio difference determined from the target speed ratio T _n ([Delta] T), is compared with a predetermined threshold value (first threshold value Y ₁ and the second threshold value Y _2).

The accelerator operation determining means 23 determines the presence or absence of an accelerator operation on the basis of the accelerator operation amount detected by the detecting means 20. The braking state is determined based on the presence or absence of the depression of the brake pedal detected by the detecting means 20. Judgment means 2
4 detects whether the vehicle is in a braking state. The result of the comparison by the threshold value comparing means 22, the accelerator operation determining means 23
When the target gear ratio deviation exceeds a threshold value in the case of gentle acceleration and rapid acceleration based on the judgment result of the braking state judgment means 24, the target gear ratio setting means 25 The gear ratio is set based on the previous target gear ratio T _n-1 and the predetermined amount (first predetermined amount T ₁ , second predetermined amount T ₂ ), so that the gear ratio changes smoothly, and the downshift quickly occurs during kickdown operation. To achieve. Specific control contents will be described below with reference to FIGS.

One example of the shift control of the continuously variable transmission according to the present invention.
An example is performed according to the flowchart shown in FIG. Figure
The control flow shown in FIG. 2 corresponds to each sampling time of the shift information.
Is executed sequentially with the control timing as the control timing. That is, the vehicle speed V, and
Throttle opening θ as accelerator operation amount_tShift information
Information is detected by various sensors as detecting means (step
1), the target gear ratio calculating means calculates
Based on the shift map with the detected value as a parameter,
This sampling time TPS_n-1, TPS _nSmell
Previous target gear ratio T_n-1And the current target gear ratio T_nTo
Each is calculated (step 2). The braking state determining means is:
The vehicle brake is off (ie, the braking state is off)
It is determined whether or not it is (step 3). Brake pedal
When the braking state is on by stepping on the
Your current target is calculated based on the shift map
Gear ratio T_n(Step 4). That is, this time target shift
This time final target as calculated by the target gear ratio calculation means
Gear ratio T_nfAnd the final target gear ratio T_nfDetermined by
Sudden gear change when vehicle speed / throttle detection signal fails in basic control
In consideration of the above, the normal shift control of the continuously variable transmission is performed.

When it is determined in step 3 that the braking state is off, the previous sampling time TP
S _{n - 1} whether the throttle opening theta _t is 0 percent in is determined by the accelerator operation judgment means (step 5). In step 5, the previous sampling period TPS _n by an accelerator operation judgment means _- the throttle opening theta _t is not 0% at _1, i.e., when it is determined that the accelerator pedal is stepped on, normal in Step 4 Shift control is performed. In Step 5, when the throttle opening theta _t is judged to be 0%, that is, trying to kick down operation, then larger accelerator pedal and the accelerator pedal even temporarily returned when no stepping on the brake pedal When stepping down, the threshold comparing means performs the next comparison. That is, the threshold value comparing means calculates the absolute value of the difference between the current target speed ratio _Tn and the previous target speed ratio _Tn-1 at the current and previous sampling times as the target speed ratio deviation ΔT (= | Tn− ₁₋ T). _n |), and it is compared whether or not the target speed ratio deviation ΔT exceeds a predetermined threshold Y (step 6).

When the target gear ratio deviation ΔT exceeds the threshold value Y, it is determined that the amount of change in the target gear ratio is too large, and the target gear ratio deviation ΔT is calculated from the previous target gear ratio T _{n -1.}
A gear ratio obtained by subtracting a predetermined amount T smaller than the predetermined value T is set as the final target gear ratio _Tnf this time (step 7). That is, for example, in the case of sudden acceleration (| T _{n -1}
−T _n |> Y), the current final target gear ratio T _nf is set to a value obtained by subtracting a predetermined amount T smaller than the target gear ratio deviation ΔT from the previous target gear ratio T _n-1 (T _nf = T _n-1
-T). That is, since the current final target gear ratio T _nf is set to the target gear ratio with a small change amount from the previous target gear ratio T _n−1 , the gear ratio is shifted to the speed increasing side, that is, the shift up side. The amount decreases, and thereafter, the vehicle quickly shifts to the deceleration side, that is, the downshift side. Note that the predetermined amount T is a value smaller than the target speed ratio deviation ΔT. However, if the predetermined amount T is smaller than the threshold value Y, the shift to the downshift side is more quickly performed. Further, as the accelerator operation amount, has been given the throttle opening theta _t, it may be an accelerator pedal depression amount.

The time change of the gear ratio at this time is shown in the graph of FIG. According to FIG. 4, the throttle opening θ
case of increasing and thus reduce to zero _t at time t ₀ moderately at time t _1, the throttle opening degree at time t ₀ theta
_The engine brake is activated in response to the decrease of _t to zero. When increasing the throttle opening theta _t at time t _1, the gear ratio is reduced by a small predetermined amount T is controlled in the upshifting direction changes as shown by the solid line A. As the engine speed increases, the upshifting is only slightly felt and there is no sense of incongruity, and the gear ratio immediately starts to increase (shift to the deceleration side) and shifts down greatly. Therefore, large torque of the engine is output from the continuously variable transmission, and powerful acceleration is obtained.
Quick kickdown is obtained.

Another example of the shift control of the continuously variable transmission according to the present invention is performed according to a flowchart shown in FIG.
In the control flow shown in FIG. 3 as well, each sampling time of the shift information is sequentially executed as a control time. Vehicle speed V and throttle opening θ, which are shift information for the continuously variable transmission
_t is detected by each sensor as the detecting means (step 11). Shift information such as the vehicle speed V and the throttle opening theta _t from the shift map of a parameter, the target speed ratio calculating means is calculated the target gear ratio at each sampling period, the preceding sampling period (TPS) _{n -} in ₁ previous target speed ratio T _{n - 1} and the current target speed ratio T _n at the current sampling period (TPS) _n is read (step 12). The braking state determining means determines, at each sampling time, the braking state of the vehicle, that is, whether or not the brake of the vehicle is off (step 13).

In step 13, when the braking state of the vehicle is not off, that is, when the braking state determining means determines that the operation state of the vehicle is in the braking state when the brake pedal is depressed, the target gear ratio setting means Since the target gear ratio T _n at the current sampling timing (TPS) _n according to the gear shift map is set to the current target gear ratio, the normal gear ratio control is performed (step 14). In step 13, the braking state of the vehicle is turned off, i.e., when the brake pedal is determined that the braking state determining means not stepped on, the last sampling time (TPS) _{n -} throttle opening theta _t in ₁ 0 % Is determined by the accelerator operation determining means (step 1).
5). If the determination in step 15 is NO, that is,
Even when there is an accelerator operation amount other than the zero operation amount, the normal gear ratio control is performed in step 14.

[0027] In the determination in step 15, the previous sampling period (TPS) _{n -} when the throttle opening theta _t is 0% in _1, the last sampling time (TPS)
The driving state of the vehicle at _{n- 1} is an engine brake operating state because the braking state is not on and the accelerator pedal is not depressed. In the operating state, the threshold value comparing means performs the previous and current sampling periods (TPS).
The target gear ratio deviation ΔT (= |) as the difference between the two target gear ratios T _n−1 and T _n at _n−1 and (TPS) _n
T _{n - 1} -T _n |) is compared whether more than a second threshold value Y ₂ (step 16). If the target gear ratio difference ΔT in step 16 does not exceed the second threshold value Y _2, both the target speed ratio T _{n - 1,} T _n target gear ratio deviation ΔT as the absolute value of the difference (= | T _{n - 1} -T _n |) whether exceeds a first threshold value Y ₁ is determined by the threshold comparison means (step 18). The first threshold value Y ₁ is a value equal to the threshold value Y used in the threshold value comparison of ΔT in step 6 of the shift control flow shown in FIG. 2, and is a value smaller than the second threshold value Y ₂ . If the target speed ratio deviation ΔT does not exceed the first threshold value Y ₁ , that is, if the change in the target speed ratio is not a large change,
In step 14, the target gear ratio T according to the gear shift map
Normal gear ratio control is performed with _n as the current final target gear ratio T _nf .

In step 18, the target gear ratio deviation Δ
T is when the exceeds the first threshold value Y ₁ threshold comparison means determines shows that the operation of the loose accelerated in the sampling period (TPS) _n from the engine braking state is performed. This target speed ratio T _n is the previous target speed ratio T _{n -} less than _1, if it is to be a rapid acceleration slightly, the target speed ratio setting means is a predetermined value that is less than the target speed ratio deviation ΔT first predetermined amount T ₁ of the previous target speed ratio T _n was _{- 1} from subtracting the gear ratio (speed increasing side) this final target speed ratio T _nf (= T _{n - 1} -T ₁₎ set (step 19 ). The first predetermined amount T ₁ is a value equivalent to the predetermined amount T reduced in step 7 shown in FIG. For example, in the case of slow acceleration | _- | A _{(T n 1 -T n> Y} 1), this final target speed ratio T _nf the previous target speed ratio T _{n - 1} from a first
It is set to a value obtained by subtracting the predetermined amount _{T 1 (T nf = T n} - 1
-T _1). Since the final target gear ratio T _nf this time is set to the target gear ratio with a small change amount from the previous target gear ratio T _{n− 1} , the change amount in which the gear ratio shifts to the speed increasing side, that is, the shift up side, is reduced. And then on the deceleration side,
Shift quickly to the downshift side. First predetermined amount T
_{Although 1} is a value smaller than the target speed ratio deviation ΔT, a value smaller than the first threshold value Y ₁ is effective for shifting to the downshift side more quickly during gentle acceleration. .

Since the second threshold value Y ₂ is larger than the first threshold value Y ₁ , if the threshold comparison means determines in step 16 that the target speed ratio deviation ΔT exceeds the second threshold value Y ₂ , Indicates that a rapid acceleration operation was performed at the sampling time (TPS) _n . If it is to be rapid acceleration, the target speed ratio setting means, the previous target speed ratio T _{n -} the gear ratio reduced by a second predetermined amount T ₂ than ₁ time the final target speed ratio T _nf (= T _{n - 1−} T ₂ ) (step 17). The second predetermined amount T ₂ is the first predetermined amount T ₁
It is chosen to be smaller. In other words, by shifting the final target gear ratio T _nf this time in small increments of the second predetermined amount T ₂ every control cycle, for example, the target gear ratio on the gear shift map during re-acceleration corresponds to the kick down direction which is the driver's will. Even if changes in the reverse shift-up direction, the shift map is not applied at that time, and the control flow is prioritized and the kick-down is smoothly performed.

FIG. 4 shows a time change of the gear ratio at this time. According to FIG. 4, if allowed to surge at time t ₁ and thus reduce to zero the throttle opening theta _t at time t ₀ to 90%, at time t ₀ to the throttle opening theta _t is reduced to zero In response, the engine brake operates. When brought into surge the throttle opening theta _t at time t _1, the speed ratio is is being controlled is reduced by a small second predetermined amount T ₂ in the upshift direction, in fact,
As the engine speed increases, the gear ratio increases (shifts to the deceleration side) with almost no shift-up felt.
Then shift down without any discomfort. Therefore, a large torque of the engine is output from the continuously variable transmission, and a strong acceleration can be obtained, so that a quick kick down can be obtained.

In the above embodiment, even if the accelerator operation amount is suddenly increased from zero operation amount and the vehicle is accelerated again without stepping on the brake, if the appropriate shift time delay is set, the shift width is too large and the shift speed is too large. It is possible to re-accelerate with a minimum time lag without taking a long time. Furthermore, although the target value determined by the shift map is the target gear ratio, the target value may be the engine speed or the speed input to the continuously variable transmission. Although the continuously variable transmission has been described as a toroidal type continuously variable transmission, the rotation of the input shaft is continuously changed by pushing a V-shaped cross-section belt from the side to change the diameter of the belt wound around the pulley. Belt-type continuously variable transmission. Although the first and second thresholds are provided as thresholds, three or more thresholds may be set.

[0032]

Since the present invention is configured as described above, it has the following effects. That is, in the transmission control device of the continuously variable transmission, the target gear ratio deviation calculated from the previous target gear ratio calculated by the target gear ratio calculating means and the current target gear ratio at the previous and current sampling times is predetermined. The threshold value comparing means compares whether or not the value is larger than the threshold value, the accelerator operation determining means determines that the accelerator operation amount at the previous sampling time is equal to or less than a predetermined value, and the current target gear ratio is In response to the fluctuation exceeding the target speed ratio exceeding the threshold value, the target speed ratio setting means subtracts a predetermined amount smaller than the target speed ratio deviation from the previous target speed ratio to the current final target speed ratio. The throttle opening is set to zero and the engine is braked. Even if the target gear ratio is once calculated to be a large value on the speed increasing side, the target gear ratio this time does not follow the target gear ratio obtained from the gear ratio map, but is calculated from the target gear ratio deviation from the previous target gear ratio. Since the gear ratio is set by subtracting a small predetermined amount, the shift-up once shifted can be reduced or reduced to a small amount, and stall feeling can be reduced or eliminated, and quick kick-down acceleration can be performed.

Also, at the time of re-acceleration, the intention of the driver (whether rapid re-acceleration or slow re-acceleration) is indirectly obtained by dividing the amount of change in the engine rotation into a plurality, and the kick down speed can be adjusted. Furthermore, by changing the approach speed to the target speed according to the amount of change in the target speed ratio during the control cycle,
The driver's intention at the time of re-acceleration (whether he wants to accelerate rapidly or slowly) can be indirectly sampled.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of a shift control device for a continuously variable transmission according to the present invention.

FIG. 2 is a flowchart showing an example of a shift control flow by a shift control device for a continuously variable transmission according to the present invention.

FIG. 3 is a flowchart showing another example of the shift control flow by the shift control device of the continuously variable transmission according to the present invention.

FIG. 4 is a graph showing a time course of a gear ratio and an accelerator operation amount controlled by the gear change control device of the continuously variable transmission shown in FIG. 1;

FIG. 5 is a graph showing a time change of a gear ratio and a throttle opening in a shift control of a conventional continuously variable transmission.

FIG. 6 is a shift map showing a relationship between a vehicle speed and a throttle opening in the case of a stepped transmission.

FIG. 7 is a schematic view showing a cross section of a part of a toroidal type continuously variable transmission shown as an example of a conventional continuously variable transmission.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Toroidal-type continuously variable transmission 20 Detecting means 21 Target gear ratio calculating means 22 Threshold comparing means 23 Accelerator operation judging means 24 Braking state judging means 25 Target gear ratio setting means θ _t Throttle opening TPS sampling timing E Engine T _n current target Gear ratio T _n-1 Previous target gear ratio T _{nf Current} final target gear ratio ΔT Target gear ratio deviation Y ₁ First threshold Y ₂ Second threshold T ₁ First predetermined amount T ₂ Second predetermined amount

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 63:06 F16H 63:06

Claims (8)

[Claims] Detecting means for detecting shift information such as a vehicle speed and an accelerator operation amount of an engine; and a continuously variable shift arranged at a subsequent stage of the engine in accordance with the shift information detected by the detecting means at each sampling time. Target speed ratio calculating means for calculating the target speed ratio of the engine, accelerator operation determining means for determining the presence or absence of an accelerator operation, the previous target speed ratio calculated by the target speed ratio calculating means at the previous and current sampling times, and the current target speed change Threshold value comparing means for comparing whether the target speed ratio deviation obtained from the ratio is greater than a predetermined threshold value, and the accelerator operation determining means determines that the accelerator operation amount at the previous sampling time is equal to or less than a predetermined value. In response to the fact that the target speed ratio deviation fluctuates beyond the threshold in the comparison by the threshold comparing means, A shift control device for a continuously variable transmission, comprising target speed ratio setting means for setting a speed ratio changed from a previous target speed ratio by a predetermined amount smaller than a target speed ratio deviation to a current final target speed ratio. 2. The transmission control device for a continuously variable transmission according to claim 1, wherein said target gear ratio setting means has a value smaller than said threshold value as said predetermined amount. 3. The threshold comparing means, wherein:
3. The continuously variable transmission according to claim 1, wherein at least a first threshold value with which the target gear ratio deviation is compared and a second threshold value that is larger than the first threshold value are determined. Control device. 4. The method according to claim 1, wherein the target gear ratio setting means includes: a first predetermined amount smaller than the first threshold value as the predetermined amount;
The shift control device for a continuously variable transmission according to claim 3, comprising a second predetermined amount smaller than the second threshold value and smaller than the first predetermined amount. 5. A braking state determining means for determining a braking state of the vehicle, wherein when the braking state determining means determines that the braking state is off, the previous sampling by the accelerator operation determining means is performed. When the accelerator operation at the time is determined, the accelerator operation determining means determines that the accelerator operation amount exceeds a predetermined value, and when the braking state determining means determines that the braking state is on. 5. The method according to claim 1, wherein the target gear ratio setting means sets the target gear ratio calculated by the target gear ratio calculating means at this sampling time as the final target gear ratio this time. A shift control device for a continuously variable transmission according to claim 1. 6. The shift control device for a continuously variable transmission according to claim 1, wherein the continuously variable transmission is a toroidal-type continuously variable transmission. 7. A target shift of a continuously variable transmission calculated based on shift information such as a vehicle speed and an accelerator operation amount, even though an operation state of the vehicle is such that an accelerator operation amount sharply increases from zero operation amount. In response to a state in which the gear ratio is shifting to the speed increasing side with a gear ratio width of a certain value or more, a speed ratio that decreases with a gear ratio width smaller than the certain gear ratio width is set as a final target gear ratio. Transmission control device for a continuously variable transmission. 8. The shift control device for a continuously variable transmission according to claim 7, wherein the driving state of the vehicle includes that a braking operation state of the vehicle is off.