JP2584748B2 - Control device for continuously variable transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a control device for a continuously variable transmission, and more specifically, it is possible to suppress slippage of a belt wound between pulleys of a continuously variable transmission. The present invention relates to a control device for a continuously variable transmission.

(Prior Art) Recently, a belt-type continuously variable transmission in which a gear ratio is automatically changed in accordance with an engine operating state has been used in passenger cars and the like. In this continuously variable transmission, the belt winding radius of an input side pulley and an output side pulley interlocked by a belt is changed by an actuator in accordance with an operating state of an engine, thereby performing a stepless speed change. The speed change operation is performed while the belt transmitting the driving force slightly slips so as to match the speed change characteristics of the continuously variable transmission. Therefore, in order to obtain a good shifting operation, it is required that the slip state of the belt with respect to the pulley can always smoothly follow the driver's accelerator operation that is performed flexibly. For example, Japanese Unexamined Patent Publication No. 56-138555 discloses that the above-described continuously variable transmission can be operated under desired conditions such as best fuel efficiency, and under such conditions, required hydraulic pressure is generated in each part of the transmission. A control device for a continuously variable transmission for a vehicle, which prevents an impact during a shift, is disclosed.
Japanese Patent Application Laid-Open No. 58-72758 discloses a flow control device for restricting a flow of oil discharged from a cylinder chamber of a driving pulley and a cylinder chamber of a driven pulley. There is disclosed a shift control device for a belt-type continuously variable transmission in which the belt tension is increased to prevent the belt from excessively slipping with respect to a pulley.

(Problems to be solved by the invention) By the way, what is called a kick down,
In the case of a rapid acceleration state in which the accelerator operation is fast and the accelerator pedal is largely depressed, the engine rotation driving force suddenly increases, so the downshift amount required for the continuously variable transmission is excessively deviating from the shift characteristics. It will be. Therefore, by controlling and adjusting the above-described continuously variable transmission, excessive slippage of the belt with respect to the pulley may not be suppressed. This excessive belt slip causes the engine to run idle, causing not only loss of drive power but also severe wear of the bell. Therefore, it is desired that measures should be taken to appropriately suppress the slip of the belt with respect to the pulley even in a sudden acceleration state such as a kick down.

The present invention has been made in view of such circumstances,
An object of the present invention is to provide a control device for a continuously variable transmission that can suppress slippage of a belt stretched between pulleys with respect to pulleys during rapid acceleration such as kick down.

(Means for Solving the Problems) In order to achieve the above object, a solution of the present invention comprises a first pulley connected to an engine and a second pulley connected to wheels.
As a control device for a continuously variable transmission in which a pulley and a belt are driven and connected by a belt, and a belt winding radius of each pulley is made variable, the transmission ratio is continuously changed. A clutch that is interposed in the power transmission path to connect and disconnect the transmission of the driving force from the engine to the first pulley so that the torque transmitted from the engine to the first pulley decreases when the fastening force decreases; A rapid acceleration state detecting means for detecting a state in which the accelerator opening degree is larger than a predetermined value requiring downshifting and an accelerator opening is larger than a predetermined value recognized as an acceleration operation, as a rapid acceleration state; When the sudden acceleration state is detected, the clutch engagement force is reduced so as to reduce the transmission torque to such an extent that the transmission drive force does not fall off, and And and control means for the switch to the half-clutch state.

According to the present invention, the first pulley connected to the engine via the clutch is operatively connected to the second pulley connected to the wheels by a belt, and the belt winding radius of each pulley changes. As a result, the speed ratio of the continuously variable transmission continuously changes. Then, when the sudden acceleration state detecting means detects a sudden acceleration state in which the accelerator pedal depression speed is larger than a predetermined value that requires downshifting and the accelerator opening is larger than a predetermined value that is recognized as an acceleration operation. By the control means, the engaging force of the clutch is reduced, and the clutch enters a so-called half-clutch state. Therefore, at the time of rapid acceleration such as kick down, the rotational force from the engine is transmitted to the first pulley in a half clutch state.
Slip between the first pulley and the belt is suppressed.

(Effects of the Invention) According to the control device for a continuously variable transmission of the present invention, at the time of sudden acceleration such as kick down, the engagement force of the clutch for connecting and disconnecting the transmission of the driving force of the engine to the pulley is reduced, and In the so-called half-clutch state, the rotational force from the engine is reduced and transmitted to the pulley, so that slippage between the pulley and the belt is suppressed, and the durability of the belt can be improved.

(Embodiment) Hereinafter, an embodiment of a control device for a continuously variable transmission according to the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the control device for the continuously variable transmission according to the present embodiment includes a primary pulley 83 connected to the engine 1 via the clutch 2 and a secondary pulley 84 connected to the wheels 6. Of the V-belt 85 in the continuously variable transmission 4 in which the transmission ratio is continuously changed by making the belt winding radius of each pulley variable. This is a device that suppresses the slip with respect to. This control device detects a state in which the accelerator pedal depression speed is greater than a predetermined value requiring downshifting and the accelerator opening is greater than a predetermined value recognized as an acceleration operation as a rapid acceleration state. State detecting means, and when the rapid acceleration state is detected by the rapid acceleration state detecting means, the clutch 2
And control means for reducing the transmission torque to such an extent that the transmission driving force does not fall off so as to reduce the transmission torque so as to bring the clutch 2 into a so-called half-clutch state. The control means is provided in the control unit 101.

In FIG. 1, reference numeral 1 denotes an engine, and an output (rotation) of the engine 1 is transmitted to a drive shaft 6 via a clutch 2, a gear box 3, a continuously variable transmission 4, and a differential gear 5. From the engine 1 to the drive wheels 6
The power transmission mechanism up to this constitutes the engine drive system.

An intake pipe 8 is connected to the engine 1 via an intake manifold 7, and the output of the engine 1 is adjusted by adjusting the opening of a throttle valve 9 provided in the intake pipe 8. Further, the gear box 3 is manually operated to set R (reverse), N
(Neutral), D (drive), and L (low) ranges can be selected. Further, the connection and disconnection of the clutch 2 and the change of the gear ratio of the continuously variable transmission 4 are automatically performed by connecting an actuator using hydraulic pressure, as described later.

Next, the clutch 2, the gear box 3, and the continuously variable transmission 4 will be sequentially described with reference to FIG. In the clutch 2, a clutch input shaft 21 is directly connected to a crankshaft of the engine 1, and a clutch output shaft 22 is provided rotatably with respect to the input shaft 21.
The clutch disk 23 is spline-fitted to the clutch. Then, by pressing the clutch disc 23 against the flywheel 24 provided integrally with the clutch input shaft 21, the two shafts 21 and 22 are connected, and conversely, the clutch disc 23 and the flywheel 24 are separated from each other. Then both shafts 21,2
It becomes a disconnected state in which the interlocking of 2 is interrupted. Then, by appropriately adjusting the pressing force of the clutch disc 23 to the flywheel 24, a so-called half-clutch state in which the fastening force is reduced can also appear.

To perform such pressure contact and separation of the clutch disc 23 with the flywheel 24, a sleeve 25 is attached to the output shaft 22.
Is slidably and rotatably fitted, and the sleeve
25 is connected to one end of a spring member 27 such as a disc spring that is swingable about a fulcrum 26, while the other end of the spring member 27 faces the back of the clutch disk 23. The clutch pressure plate 28 is connected to the clutch pressure plate 28.
As a result, when the sleeve 25 moves rightward in the drawing, the clutch pressure plate
28, that is, the clutch disk 23 is displaced to the left in a connected state. Conversely, when the sleeve 25 moves leftward from this connected state, the disengaged state is established. In the half-clutch state,
Clutch disc 23 is clutch pressure plate 28
Although the sleeve 25 is pressed against the flywheel 24, the sleeve 25 is at an intermediate position between the two, and the pressing force is adjusted to be low via the spring member 27. In such a half-clutch state, the rotational force input from the crankshaft to the clutch input shaft 21 has a slight play with the clutch output shaft.
22 to reduce the so-called transmission torque.
Therefore, at the time of sudden acceleration such as kick down, the pressure contact force of the clutch disc 23 to the flywheel 24 (that is, the clutch engagement force) is reduced to cause the above-described half-clutch state to appear, as described later. Slip of the V-belt 85 with respect to the primary pulley 83 or the secondary pulley 84 in the continuously variable transmission 4 can be suppressed.

The displacement of the sleeve 25 in the left-right direction in FIG. 2 is adjusted by a cylinder device 29. That is, the piston rod 30 of the cylinder device 29 is connected to one end of a swing arm 32 that can swing around a fulcrum 31, while the other end of the swing arm 32 is connected to the back of the sleeve 25. It is connected to. Further, an oil chamber 34 defined by a piston 33 of the cylinder device 29 is connected to a class solenoid valve 36 formed of a three-way electromagnetic switching valve via a pipe 35, and the clutch solenoid valve 36 is connected to a discharge side of a hydraulic pump 37. It is connected to a pipe 38 extending from the storage tank 39 and a pipe 40 extending from the reserve tank 39, respectively. The suction side of the hydraulic pump 37 is connected to a pipe 42 extending from the reserve tank 39 via a filter 41.

The clutch solenoid valve 36 has two solenoids 36a and 36b for connection and disconnection.
When the solenoid 36a is excited (the solenoid 36b is demagnetized), the hydraulic pump 37 communicates with the oil chamber 34 of the cylinder device 29, the piston rod 30 is extended, and the clutch 2 is connected.
Then, the transmission torque of the clutch 2 at the time of this connection increases as the supply amount of the oil liquid to the oil chamber 34 increases (the pressing force of the clutch disk 23 against the flywheel 24 increases). When the cutting solenoid 36b is excited (the connection solenoid 36a is demagnetized), the oil chamber 34
Is released to the reserve tank 39, the piston rod 30 is contracted by the return spring 43, and the clutch 2
Is disconnected. Further, when both the solenoids 36a and 36b are demagnetized, the oil chamber 34 is closed, and the piston rod 30 is held as it is.

The gear box 3 has an input shaft constituted by the clutch output shaft 22, and a first gear 51 and a second gear 52 having a smaller diameter than the first gear 51 are integrally formed on the clutch output shaft 22. I have. A gearbox output shaft 53 is disposed in parallel with the output shaft 22, and a back gear 54 that constantly meshes with the second gear 52 is provided between the two shafts 22 and 53. ing. Gearbox output shaft
A large-diameter intermediate gear 55 that constantly meshes with the first gear 51 is rotatably fitted to the first gear 51, while a sleeve 56 is integrated with the first gear 51. A clutch gear 57 is always spline-fitted to the sleeve 56, and the clutch gear 57
Can be meshed with the back gear 54 with its axial displacement, and can also be spliced with the intermediate gear 55.

When the clutch gear 57 is at the rightmost position as shown in FIG.
The rotation of the first gear 51, the intermediate gear 55, the clutch gear 57
The rotation of the output shaft 53 at this time corresponds to the forward direction of the vehicle. When the clutch gear 57 is displaced to the leftmost position in the figure, the rotation of the clutch output shaft 22 is transmitted to the gear box output shaft 53 via the second gear 52, the back gear 54, the clutch gear 57 and the sleeve 56. The rotation direction of the output shaft 53 at this time corresponds to the backward direction of the vehicle. Further, when the clutch gear 57 is at the intermediate stroke position in the left-right direction in the figure (when the clutch gear 57 is not in spline engagement with the intermediate gear 55 and is not in mesh with the back gear 54), the clutch output shaft 22 and the gear box The neutral state is established in which the link with the output shaft 53 is interrupted.

The displacement position of the clutch gear 57 is adjusted by a cylinder device 58. That is, the piston rod 59 of the cylinder device 58 is linked to the clutch gear 57 via the interlocking arm 60 so that when the piston rod 59 is extended, the clutch gear 57 is displaced to the left in FIG. Has become. In the cylinder device 58, two oil chambers 62 and 63 are defined by the piston 61, and the oil chamber 62 is connected via a pipe 64, and the oil chamber 63 is connected via a pipe 65. 66 connected to each other. The manual valve 66 is connected to the hydraulic pump 37 via a pipe 67 and to the reserve tank 39 via a pipe 68, respectively.

Such a manual valve 66 is provided by manually operating an operation lever 70 that can swing around a fulcrum 69.
The operation lever 70 is rotated in the clockwise direction in FIG.
Range, D range, L range can be taken. In this R range position, the oil chamber 62 is
When the oil chamber 63 is opened to the reserve tank 39 while being communicated with 37, the piston rod 59 is extended, and the gear box 3 is set in the backward connection state. In the N range position, both oil chambers 62 and 63 are both opened to the reserve tank 39, and the balance action of the return spring 71 causes the piston rod 59, that is, the clutch gear 57 to be in the intermediate stroke position. Box 3 is in the neutral position described above. Further, in the D range position, the oil chamber 62 is opened to the reserve tank 39, the oil chamber 63 is communicated with the hydraulic pump 37, the piston rod 59 is reduced, and the gear box 3 is connected to the aforementioned forward connection. State. In the L range position, the manual valve 66
Is the same position as the D range.

The continuously variable transmission 4 has an input shaft 81 and an output shaft 82 parallel to each other. The input shaft 81 has a primary pulley 83 as a first pulley, and the output shaft 82 has a primary pulley as a second pulley. A secondary pulley 84 is provided, and a V-belt 85 is wound between the pulleys 83 and 84. The primary pulley 83 includes a fixed flange 86 integral with the input shaft 81 and a movable flange 87 slidably displaceable with respect to the input shaft 81. The winding radius of the V-belt 85 with respect to the primary pulley 83 is increased with approaching to the fixed flange 86 with an increase in the diameter. Similarly to the primary pulley 83, the secondary pulley 84 also includes a fixed flange 89 integrated with the output shaft 82 and a movable flange 90 slidably displaceable with respect to the output shaft 82. The V-belt 85 is configured such that the radius of winding of the V-belt 85 around the secondary pulley 84 increases as the amount of oil supply to the hydraulic actuator 91 increases and approaches the fixed flange 89.

The hydraulic actuator 88 is connected via a pipe 92, and the hydraulic actuator 91 is connected via a pipe 93 to a shift solenoid valve 94 formed of a three-way electromagnetic switching valve, and the shift solenoid valve 94 is connected to a hydraulic pump via a pipe 95.
37, and connected to a reserve tank 39 via a pipe 96.

The speed change solenoid valve 94 is provided with two
Having two solenoids 94a and 94b,
(When the deceleration solenoid 94b is demagnetized), the hydraulic actuator 88 is connected to the hydraulic pump 37,
Since the hydraulic actuator 91 is opened to the reserve tank 39, the winding radius of the V belt 85 around the primary pulley 83 increases, while the winding radius around the secondary pulley 84 decreases, and the rotation speed of the output shaft 82 increases. The speed is increased (the gear ratio is small). On the other hand, when the deceleration solenoid 94 is excited (the deceleration solenoid 94a is demagnetized),
Since the hydraulic actuator 91 is communicated with the hydraulic pump 37 and the hydraulic actuator 88 is opened to the reserve tank 39, the winding radius of the V-belt 85 around the primary pulley 83 decreases, while the winding radius around the secondary pulley 84 decreases. As a result, the output shaft 82 enters a deceleration state in which the number of revolutions thereof decreases (a large gear ratio). Of course, the gear ratio is obtained by dividing the rotation speed of the input shaft 81 by the rotation speed of the output shaft 82 (the winding radius of the V belt 85 around the secondary pulley 84 divided by the winding radius around the primary pulley 83). .

Reference numeral 97 in FIG. 2 denotes an electromagnetic relief valve, which keeps the illustrated position during clutch control and gear ratio control described below.

1 and 2, reference numeral 101 denotes a control unit to which signals from the respective sensors 102 to 109 are input, while the control unit 101 outputs a clutch solenoid valve 3 to the control unit 101.
6. Signals are output to the shift solenoid valve 94 and the relief valve 97. The sensors 102 to 109 will be described. The sensor 102 is a throttle sensor that detects the opening of the throttle valve 9. The sensor 103 is a rotation speed sensor that detects the rotation speed Ne of the engine 1 (same as the rotation speed E of the clutch input shaft 21 in the embodiment). Sensor
Reference numeral 104 denotes a rotation speed sensor that detects the rotation speed C of the clutch output shaft 22. The sensor 105 includes R, N,
This is a position sensor that detects the positions of D and L. The sensor 106 is a rotation speed sensor that detects the rotation speed Np of the input shaft 81 of the continuously variable transmission 4. The sensor 107 is a vehicle speed sensor that detects the rotation speed of the output shaft 82 of the continuously variable transmission 4, that is, the vehicle speed. The sensor 108 is an accelerator sensor for detecting the opening degree of the accelerator pedal 110 and obtaining the change speed.
The sensor 109 is a brake sensor for detecting whether or not the brake pedal 111 has been operated.

Next, the contents of control by the control unit 101 will be described with reference to the flowcharts shown in FIGS.

FIG. 3 shows the entire processing system.
After the system initialization in step B,
Various data required for control are input at
The clutch control in step C and the gear ratio control in step D are performed (some are read during the control in step D in consideration of responsiveness). In the following description, a routine for clutch control and a routine for speed ratio control will be described separately.

I. Clutch Control Routine (FIG. 4) First, at step 120, it is determined whether or not the operating lever 70, that is, the gear box 3, is in the N range. (Step 15 in the speed ratio control routine shown in FIG. 5)
7-160) is set, that is,
It is determined whether the vehicle is in a rapid acceleration state including the time of kick down. If the acceleration flag is set and the vehicle is in a rapid acceleration state, the routine proceeds to step 141, where the gear ratio N is read. The gear ratio N is, as described above, the rotational speed of the output shaft 82 of the continuously variable transmission 4 detected by the vehicle speed sensor 107 with respect to the rotational speed Np of the input shaft 81 of the continuously variable transmission 4 detected by the sensor 106. It is calculated as the ratio of Ns. Next, the routine proceeds to step 142, where the read gear ratio N and the required downshift amount (temporary target input rotational speed tNp) obtained based on a previously stored shift control characteristic diagram (not shown) are used. ,
A gear ratio fixed position for obtaining an appropriate degree of slip is calculated. Thereafter, the process proceeds to step 143, where the target clutch pressure Pc corresponding to the gear ratio fixed position is calculated by an equation stored in advance. The target clutch pressure Pc is set so that the clutch 2 is in a so-called half-clutch state and the V-belt 85 of the continuously variable transmission 4 does not slip excessively with respect to the pulley so that the driving force of the entire vehicle does not drop out. A value is required. In consideration of the durability of the clutch 2 and the like, the larger the downshift amount, the higher the target clutch pressure Pc is calculated so that the engagement force of the clutch 2 is increased.

Next, at step 144, it is determined whether or not the input rotation speed Np at that time has reached the temporary target input rotation speed tNp.
If it has reached, it is considered that the downshift has been completed, and the routine proceeds to step 126, where the connection solenoid 36a is turned on, the disconnection solenoid 36b is turned off, and the clutch 2 is engaged.
If it has not reached, the routine proceeds to step 145, where the clutch 2 is adjusted to the target clutch pressure Pc, and a so-called half-clutch state is set. Therefore, even during a kick down in which an excessive shift down amount is required, a sufficient acceleration can be obtained without any drop in the driving force, and the V
The durability of the belt is improved without excessive slippage. By the way, at the time of the kick down described above, the suddenly increased rotational force is transmitted from the engine 1 to the primary pulley 83 of the continuously variable transmission 4 and the winding radius of the primary pulley 83 around the V-belt 85 is small (the secondary pulley 83). (84 side is greatly changed). Therefore, the sliding contact resistance between the V-belt 85 and the primary pulley 83 changes so as to be further reduced, so that the V-belt 85 is easily slipped. Next, at step 146, in order to prevent the engine 1 from overrunning, when the engine speed Ne exceeds 7,000 rpm, safety measures are taken such that the clutch 2 is engaged.

If the acceleration flag has not been set in step 121, the process proceeds to step 122, and clutch control surrounded by a broken line as already proposed is performed.
That is, in step 122, the vehicle speed is high (for example, 10 k
(m / h or more), and if the vehicle speed is high, the vehicle speed flag is set in step 123, and then step 124
Move to. In step 124, a differential value E 'of the rotational speed E of the clutch input shaft 21 is determined, and it is determined whether the differential value E' is positive indicating an increase in the rotational speed, and the differential value E 'is positive. At times, the process proceeds to step 125. In step 125, it is determined whether or not the rotation speed E of the clutch input shaft 21 is higher than the rotation speed C of the clutch output shaft 22. If E> C, the process proceeds to step 126. In step 126, while the connection solenoid 36a of the clutch solenoid valve 36 is excited, the clutch 2 is connected by demagnetizing the disconnection solenoid 36b, that is, the transmission torque thereof is increased. If it is determined in step 125 that E> C is not satisfied, the process proceeds to step 128, in which the connection and disconnection solenoids 36a and 36b of the clutch solenoid valve 36 are both demagnetized, and the transmission torque of the clutch 2 is maintained as it is.

If it is determined in step 124 that E '> 0, the process proceeds to step 127, where it is determined whether E <C. If E <C, the routine proceeds to step 126, where the clutch 2 is engaged, and E <C
If not, the routine proceeds to step 128, where the connected state of the clutch 2 is maintained.

The flow from step 124 to 125 described above is based on the assumption that the rotation of the clutch input shaft 21 is increasing, and the flow from step 125 to 126 is that the rotation speed E of the clutch input shaft 21 Since the rotation speed is higher than the rotation speed C, it is necessary to increase the transmission torque of the clutch 2. Therefore, the connection is performed to increase the transmission torque of the clutch 2. This case corresponds to, for example, a so-called half-clutch connection state during normal start. Since the flow from step 125 to step 128 is performed when the transmission torque of the clutch 2 is just balanced, the clutch 2 is held in that state. In this case, for example, a half clutch at the time of normal starting is used. This corresponds to the holding state.

Conversely, the flow from step 124 to 127 is based on the assumption that the rotational speed of the clutch input shaft 21 is decreasing, and the transmission and reception of the transmission torque between the clutch input shaft 21 and the clutch output shaft 22 has just started from step 124. Since the flow is opposite to the flow to 125, it is checked whether or not E <C contrary to the determination in step 125. Steps 127 to 126
This flow corresponds to, for example, a case where the vehicle is changed to the D range while the vehicle is traveling with the operation lever 70 kept in the N range, and in this case also, a so-called half-clutch state is formed. The flow from step 127 to 128 corresponds to, for example, a deceleration running state using an engine brake.

On the other hand, if it is determined in step 120 that the vehicle is in the N range, the process proceeds to step 130 after resetting the vehicle speed flag in step 129. In step 130, the connection solenoid 36a of the clutch solenoid valve 36 is demagnetized while the disconnect solenoid 36b is excited to disconnect the clutch 2. That is, in this case, since it is clear that the driver himself has requested the neutral state, the clutch 2 is disconnected unconditionally.

If it is determined in step 122 that the vehicle speed is low, the process proceeds to step 131, where it is determined whether or not the accelerator pedal 110 is in the ON state. If it is not ON, it means that the output of the engine 1 has not been requested, so the routine proceeds to step 132, where it is determined whether or not the vehicle speed flag is set. Then, when the vehicle speed flag is set, the vehicle speed has not yet sufficiently decreased, and in this case, the process proceeds to step 133, where it is determined whether or not the brake pedal 111 is depressed ON. Is determined. And when the brake is ON
The routine proceeds to 134, where it is determined that the engine speed Ne is equal to or less than 1,500 rpm.
The process proceeds to 30 (disengagement of clutch 2). Step 13
If it is determined in step 3 that the brake has not been turned on, the process proceeds to step 135, where the engine speed Ne is 1,000.
If it is determined that the rotation speed is equal to or lower than the rpm, the processing of step 130 is performed via step 129 (disengagement of the clutch 2). Then, if it is determined in step 134 that the rotation speed Ne of the engine 1 is not less than 1,500 rpm,
If it is determined that the rotation speed is not lower than the rpm, the process proceeds to step 124, and the above-described processing is performed.

As described above, the reason why the magnitude of the engine speed Ne as a criterion for determining whether or not the clutch 2 is disengaged by the ON / OFF operation of the brake is changed is that at the time of the brake operation,
Considering that the decrease in vehicle speed is faster than during non-braking,
This is to allow time to avoid the danger of engine stall. If it is determined in step 132 that the vehicle speed flag is not set, in order to prevent engine stall,
The process of step 130 is performed via step 129 (disengagement of clutch 2).

II. Gear Ratio Control Routine (FIG. 5) In this embodiment, first, at step 151, the rotational speed sensor 103
, The rotation speed Ne of the engine 1 is increased by the rotation speed sensor 106 in step 152.
However, in step 153, the accelerator opening α is read by the accelerator sensor. And step 154
Then, the accelerator pedal depression speed α 'is calculated. Next, at step 155, a shift control characteristic diagram (not shown)
Based on the target input speed TN corresponding to the accelerator opening α
p is calculated, and the routine goes to step 156.

In step 156, it is determined whether or not the acceleration flag is set.
Then, it is determined whether or not the accelerator pedal depression speed α ′ is greater than a predetermined value ε ′ that requires downshifting. If α ′> ε ′, the process proceeds to step 158, and the tentative target input rotation speed to be shifted down from the shift control characteristic diagram
tNp is calculated. Then, the processing proceeds to step 159, whether it is larger than the predetermined value alpha ₁ for the accelerator opening alpha is found to be clearly accelerating operation is determined. α> α ₁
If so, the flow shifts to step 160, the acceleration flag is set, and the flow shifts to step 161. In step 161, the input rotation speed Np at that time is compared with the above-mentioned provisional target input rotation speed tNp, and if Np <tNp, the process proceeds to step 165, where the deceleration solenoid 94b is turned on and the speed-up solenoid 94a is turned off. The shift down is performed. The input speed Np is the tentative target input speed tN
If it is not less than p, the process proceeds to step 162, where the input rotational speed Np ≧
It is determined whether it is 5,000 rpm. If Np ≧ 5,000 rpm, the process proceeds to step 163, where the acceleration flag is turned off,
Move to step 164. In step 164, the input rotation speed Np is compared with the target input rotation speed TNp, and if Np <TNp, the flow shifts to step 165 to shift down. Np ≧ T
If Np, the process proceeds to step 166, where the speed increasing solenoid 94a is
ON, the deceleration solenoid 94b is turned OFF, and the upshift is performed. Here, according to steps 157 and 159, the accelerator pedal depression speed is larger than the predetermined value ε ′ that requires downshifting, and the accelerator opening is the predetermined value α that is recognized as an acceleration operation.
A rapid acceleration state detecting means for detecting a state larger than ₁ as a rapid acceleration state is constituted.

If the acceleration flag is set in step 156, the process proceeds to step 159. If α ′> ε ′ is not satisfied in step 157, the process proceeds to step 163. In step 159, alpha> alpha ₁ Otherwise, step 163
Move to. If Np <5,000 rpm in step 162, the process proceeds to step 167, in which both the speed increasing solenoid 94a and the speed reducing solenoid 94b are turned off, and the gear ratio is fixed.

As described above, according to the present embodiment, when the engine speed Ne suddenly increases, for example, at the time of kick down, a so-called half-clutch state of the clutch 2 appears,
By reducing the transmission torque to such an extent that the driving force of the entire vehicle does not drop out, slippage between the primary pulley 83 or the secondary pulley 84 and the V-belt 85 can be suppressed. Therefore, during driving, a smooth acceleration / shift operation in accordance with the accelerator operation of the driver can be obtained at all times, the wear of the V-belt 85 is reduced, and the durability is improved.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing an embodiment of the present invention, FIG. 2 is an overall system diagram, FIG. 3 is a flowchart showing overall control contents, FIG. 4 is a flowchart of clutch control,
FIG. 5 is a flowchart of gear ratio control. 1 ... engine, 2 ... clutch, 6 ... wheels, 83 ...
1st pulley (primary pulley), 84 second pulley (secondary pulley), 85 belt (V belt), 10
6: rotational speed sensor, 107: vehicle speed sensor, 108: accelerator sensor, 101: control unit (control means).

Claims (1)

(57) [Claims] 1. A first pulley connected to an engine and a second pulley connected to wheels are operatively connected by a belt.
What is claimed is: 1. A control device for a continuously variable transmission, wherein a speed change ratio is continuously changed by making a belt winding radius of each pulley variable, and provided in a power transmission path from the engine to a first pulley. The clutch that disconnects and transmits the driving force from the engine to the first pulley and the accelerator pedal depressing speed require a downshift so that the torque transmitted from the engine to the first pulley decreases when the fastening force decreases. A rapid acceleration state detecting means for detecting, as a rapid acceleration state, a state in which the accelerator opening is greater than a predetermined value and the accelerator opening is greater than a predetermined value recognized as an acceleration operation; When it is detected, the engagement force of the clutch is reduced so as to reduce the transmission torque to such an extent that the transmission drive force does not fall out, and the clutch is brought into a half-clutch state. Control system for a continuously variable transmission, characterized in that it comprises a means.