JP3227748B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change by continuously changing a winding diameter ratio of a belt wound around a pair of pulleys.
The present invention relates to a shift control device for a continuously variable transmission.

[0002]

Conventionally, wound around the drive belt between the primary pulley and the secondary pulley, a continuously variable transmission of the belt drive to perform continuously variable by changing the diameter ratio winding belt that is wound around the pulleys Machines are known. The continuously variable transmission comprises the hydraulic actuator to contact and separation operation the relative distance of the primary and the stationary pulley member of the secondary pulleys and the movable pulley member, a transmission ratio determined according to the operating information of the vehicle To be the primary hydraulic actuator
Control the hydraulic pressure supplied to the
Secondary hydraulic pressure to achieve the determined line pressure
It is configured to control the hydraulic pressure supplied to the actuator .

[0003] In this case, the conventional control means, for example, as shown in FIG. 14, captures the target primary pulley speed Wpo and the actual primary pulley rotation speed Wp equivalent target gear ratio, the deviation E1 (= Wpo- Wp), and the change gain K1 for decreasing the responsiveness as the engine speed increases.
And a change gain K2 for increasing responsiveness in accordance with an increase in the deviation between the actual value and the target value of the primary pulley, and calculating a basic shift speed Vi1 by multiplying the deviation E1 by both gains K1 and K2. Vi1 is sequentially integrated to obtain a deviation from the previous value, and the deviation is multiplied by a limiter to obtain a correction coefficient 1 / Z
To obtain the integral corrected shift speed ViI. Then, the shift speed Vi is calculated by adding the basic shift speed Vi1 and the integral corrected shift speed ViI, and the electromagnetic control valve is driven by the shift speed signal Du corresponding to the shift control oil pressure Pc capable of achieving the shift speed Vi. , The electromagnetic control valve is the shift control hydraulic pressure Pc
Divides the adjustment, transmission ratio control valve which receives the transmission control oil pressure Pc is supplied to the primary pulley control hydraulic pressure to the primary hydraulic actuators, gear ratio of the continuously variable transmission and the target speed ratio I
It is configured to be.

[0004]

By the way, as described above, the target primary pulley rotational speed Wp corresponding to the target gear ratio is obtained.
o and the deviation E1 (= Wp) between the actual primary pulley rotation speed Wp.
o-Wp) and multiplying the deviation E1 by the gains K1 and K2 for correcting the responsiveness obtained from the fixed map to obtain the basic shift speed Vi1. Responsibility is not considered. That is, when the vehicle suddenly enters the braking state during overdrive and stops, the speed of returning the winding ratio of the primary pulley and the secondary pulley of the continuously variable transmission to the full low state is too slow, and the speed does not return completely. The belt stops halfway and falls into a state where sufficient tension cannot be applied to the belt. As a result, at the time of the next start of the vehicle, a belt slip occurs, a slip between the belt and the pulley is likely to occur, and the belt and the pulley are likely to be unevenly worn, thereby causing a problem that the belt and the pulley are damaged.

An object of the present invention is to provide a shift control device for a continuously variable transmission which can prevent both pulleys from being damaged during a sudden braking.

[0006]

In order to achieve the above object, an invention according to claim 1 comprises a primary pulley on an input shaft connected to an engine, and a secondary pulley on an output shaft connected to a drive shaft. , an endless belt spanning between the pulleys, a primary hydraulic actuator for changing the winding diameter of the endless belt in the primary pulley, a secondary hydraulic pressure to change the winding with only the diameter of the endless belt in the secondary pulley In a shift control device for a continuously variable transmission for a vehicle comprising an actuator,
And the target primary pulley rotational speed setting means for setting a target primary pulley rotational speed in response to the engine load, the primary hydraulic Akuchiyuetahe supplying oil in accordance with the target primary pulley rotational speed set by the target primary pulley rotation speed setting means A shift control valve for controlling the amount, a line pressure setting means for setting a line pressure according to the operating state of the vehicle, and a hydraulic pressure supplied to the secondary hydraulic actuator in accordance with the line pressure set by the line pressure setting means. A pressure regulating valve to be controlled; a deceleration rate detecting means for detecting a deceleration rate of the vehicle; an oil temperature detecting means for detecting a temperature of oil supplied to the primary hydraulic actuator; when the deceleration rate exceeds a predetermined value , A sudden braking state determining means for determining that the vehicle is in a braking state; and A line pressure correcting means for correcting the line pressure set by the line pressure setting means to a high pressure side; and, when it is determined that the braking state is abrupt, based on the oil temperature, the target primary pulley rotational speed setting means. A target primary pulley rotation speed correcting means for correcting the set value to the high rotation side, and a deviation between the target primary pulley rotation speed and the actual primary pulley rotation speed corrected by the target primary pulley rotation speed correcting device. Target shift speed setting means for setting a target shift speed, and shift control means for controlling the pressure regulating valve according to the line pressure correction value and controlling the shift control valve according to the target shift speed. It is characterized by having.

[0007]

The target primary pulley rotation speed setting means sets the target primary pulley rotation speed according to the engine load,
Controlling the primary pressure Akuchiyuetahe supplying oil quantity in accordance with the target primary pulley rotational speed set by the speed change control valve is desired primary pulley speed setting means, the line pressure setting means a line pressure according to the operating condition of the vehicle The pressure control valve controls the hydraulic pressure supplied to the secondary hydraulic actuator in accordance with the line pressure, the deceleration rate detecting means detects the deceleration rate of the vehicle, and the oil temperature detecting means
Detects the temperature of the oil supplied to the hydraulic actuator, and when the deceleration rate exceeds a predetermined value, the sudden braking state determining means determines that the braking state is sudden, and when the braking state is determined, the line pressure correction is performed. The means corrects the line pressure to the high pressure side, and when it is determined that the vehicle is in the sudden braking state, the target primary pulley rotation speed correction means changes the set value set by the target primary pulley rotation speed setting means based on the oil temperature. The target shift speed setting means corrects the rotation speed to the high rotation side, and the target shift speed setting means sets the target shift speed based on the deviation between the target primary pulley rotation speed corrected by the target primary pulley rotation speed correction means and the actual primary pulley rotation speed, and performs shift control. Means to line pressure correction value
Control the pressure control valve according to the
Control the transmission control valve. During sudden braking,
Drive the pressure regulating valve according to the line pressure for
Immediate pulley rotation speed for primary brake pulley
Switching at the target speed based on the speed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The continuously variable transmission shown in FIG. 1 has a continuously variable transmission 2 on a power transmission system P connected to an engine 60 of a vehicle.
0 is controlled. Here, the engine 60 is an electronically controlled fuel injection type four-cycle engine, and various devices such as an injector 1 for injecting fuel and a spark plug 2 for igniting an air-fuel mixture are controlled by a DBWECU 3 as electronic control means of the engine. And this DBW
The ECU 3 includes a continuously variable transmission (CVT) 2 in the power transmission system P.
The CVT ECU 21 which is an electronic control unit of the CV. The two ECUs 3 and 21 are connected by a communication line so that signals can be exchanged between the two ECUs 3 and 21 at all times.

The DBWECU 3 is connected to an actuator 11 for driving the throttle valve 9 as an intake air amount operating means which is driven independently of the operation of an accelerator pedal 10 as an artificial operating member. An electromagnetic control valve 23 for hydraulically controlling the shift speed of the step transmission 20 and an electromagnetic control valve 40 for adjusting the line pressure are connected. Here, the overall configuration of the engine 60 will be briefly described. The flow rate of the intake air sucked from the air cleaner element 5 is measured by a Karman vortex airflow sensor 6 immediately after the intake air. In the air cleaner body 4, in addition to the air flow sensor 6, devices such as an atmospheric pressure sensor and an atmospheric temperature sensor (not shown) are provided, and various data relating to the intake air are measured and input to the DBWECU 3. It has a well-known configuration.

The amount of intake air flowing into the throttle body 8 from the air cleaner body 4 through the intake pipe 7 is controlled by a butterfly type throttle valve 9. The throttle valve 9 is opened and closed by an actuator (in this embodiment, a step motor) 11, not by an accelerator pedal 10 depressed by the driver. In this embodiment,
A so-called DBW (drive-by-wire) system in which the actuator 11 is controlled by the DBWECU 3 is employed. In the figure, reference numeral 12 denotes a throttle position sensor (hereinafter, a throttle sensor) that outputs opening degree information of the throttle valve 9 as intake air amount information, and a detection signal thereof is input to the DBWECU 3.
The accelerator pedal 10 is provided with an accelerator opening sensor 13 as acceleration request detecting means. The depression amount θa is converted into an electric signal as driver's acceleration request information and input to the DBWECU 3. Here, the throttle opening θs is regarded as one of the accelerator opening θa.

The intake gas flows into the intake manifold 15 from the throttle body 8 via the surge tank 14, and becomes an air-fuel mixture by the fuel injected from the injector 1 according to a command from the DBWECU 3. The air-fuel mixture becomes exhaust gas after the explosion / expansion process of the engine 60 ends, flows into the exhaust manifold 16, and after harmful components are removed through an exhaust gas purification device (not shown), the mixture is introduced into the atmosphere from a muffler (not shown). Has been released. Reference numeral 24 denotes an engine rotation sensor that outputs engine rotation information. The continuously variable transmission 20 in FIG. 4 is connected to the crankshaft of the engine 60 via a fluid coupling 41 and a planetary gear type forward / reverse switching device 42.

Here, the continuously variable transmission 20 has a primary pulley 26 having a primary shaft 22 integrally connected to an output shaft of a forward / reverse switching device 42 and a secondary shaft 29 having a secondary shaft 29 for outputting a rotational force to the speed reducer 30. A pulley 28 is provided, and a steel belt 27 is stretched over the primary pulley 26 and the secondary pulley 28. The secondary shaft 29 is configured to transmit torque to the drive wheels 32 of the drive shaft 31 via a speed reducer 30 and a differential (not shown). As shown in FIG.
Both pulleys 26 and 28 are configured in two parts, and the movable pulley members 261 and 281 are fixed pulley members 262 and 282.
It is fitted outside so as to be able to move relative to and away from each other so that relative rotation is impossible. The movable pulley members 261 , 281 and the fixed pulley member 26
2 and 282 , a primary cylinder 33 as a hydraulic actuator for operating the relative distance between the two pulleys.
And a secondary cylinder 34 are formed .

A pair of rotation sensors s1 and s2 for detecting the rotational speeds Wp and Ws of the primary pulley 26 and the secondary pulley 28 are mounted as means for detecting the actual speed ratio In (= Wp / Ws). In this case, by moving the movable pulley 261 closer to the fixed pulley 262 of the primary pulley 26 and increasing the winding diameter of the primary pulley, the movable pulley 281 is separated from the fixed pulley 282 of the secondary pulley 28. the winding diameter is small, the high gear position, and is configured so as to achieve low gear position by operating in reverse. The hydraulic circuit of the continuously variable transmission 20 will be described with reference to FIG. The hydraulic circuit includes an oil pump 37, and the discharge oil is supplied to the fluid coupling 41, the forward clutch 43 and the reverse clutch 44 of the forward / reverse switching unit 42, and the primary cylinder 33 and the secondary cylinder 34 of the continuously variable transmission 20. You.

Here, the oil pump 37 is driven in accordance with the rotation of the engine, changes its oil pressure and supplies it to the line pressure line 49. Line pressure Lilly in this order line pressure passage 49 for restricting the maximum allowable pressure of the discharge pressure of the oil pump 37
Off valve 47 is mounted, moreover regulator valve 48 so as pressure regulating the line pressure to the set value is attached. The regulator valve 48 changes the oil pressure of the line pressure port 481 to the drain port 483 according to the rightward movement of the land 482.
And adjust the oil pressure. The hydraulic pressure adjustment is performed by the pilot pressure supplied to the left end of the spool 484 and the spring 63.
Control pressure and spring 64 supplied to the right end of spool 484
The balance operation is performed. The pilot pressure is
The pressure is regulated and controlled by a modulator valve 53 described later.
Pressure Ru der controls the CVTECU21 through the solenoid control valve 40.

Part of the line pressure line 49 is a clutch module.
Is connected to over motor valve 50, hydraulic fluid pressure regulated to the set value by Doben is supplied to the manual valve 52 through the clutch oil passage 51. The manual valve 52 is interlocked with a manual shift lever for shifting gears, so that the forward side D,
2 and L, a reverse R range, and a neutral N and parking P range. The manual valve 52 connects the forward clutch 43 and the clutch oil passage 51 when the range is forward D, 2 or L, and
Chi are joined. At this time, the engine rotation is transmitted to the continuously variable transmission 20 in the forward rotation direction , while the engine rotation is transmitted to the continuously variable transmission 20 in the reverse rotation direction in the reverse R range.

A part of the line pressure line 49 branches and is adjusted to a set value by a pressure control modulator valve 53, and the hydraulic pressure is controlled by electromagnetic control valves 23 and 40.
The pressure is adjusted to a constant value and the control pressure
The right end is supplied to the right end of a speed ratio control valve 54 described later.
You. Note the electromagnetic control valve 23 is connected to CVTECU21, and outputs the shift control hydraulic pressure Pc in accordance with the transmission ratio signal and the transmission speed signal to the variable speed ratio control valve 54. The primary cylinder 33 and the secondary cylinder 34 of the continuously variable transmission 20 are respectively connected to a main port 541 and a sub port 542 of the speed ratio control valve 54, and in particular, the secondary cylinder 34 is directly connected to a line pressure path 49. Here, the gear ratio control valve 54 includes a pilot port 543 for receiving the gear shift control oil pressure Pc of the electromagnetic control valve 23 in addition to the main and auxiliary ports 541 and 542, and a pressure control module.
Over data tone undergo adjustment pressure from the valve 53 pressure port 54
4. A drain port X communicating with the oil tank 55 is provided, and switching of the oil path is controlled by the spool 56.

Here, the spool 56 opposing the pilot port 543 receives the shift control pressure Pc to the left, and the other end receives the adjustment pressure and spring force in the opposite direction, and switches to the balance position. In this case, the spool 56
The drain port X is closed in response to the rightward movement (the shift control oil pressure Pc decreases), is completely closed after the constant movement, and the communication port between the main port 541 and the sub port 542 increases after the constant movement. The primary pulley control hydraulic pressure Pp of the primary cylinder 33 is increased (the secondary pulley control hydraulic pressure Ps is normally a line pressure), and the actual gear ratio In
Reduces the the high gear position, the reverse leftward movement of the spool 56 (speed change control hydraulic pressure Pc is increased) is released drain port X in response to the reduce the primary pulley control pressure Pp (secondary pulley control pressure Ps is normal state line pressure), increases the actual gear ratio in a low gear position that it is possible. In addition, the electromagnetic control valve 2 that generates the shift control hydraulic pressure Pc
3 is that if the duty ratio Du it receives is low, the hydraulic pressure Pc
And the hydraulic pressure Pc is increased when the duty ratio Du is high. Note that reference numeral 6 in FIG.
_{Reference numeral} 1 denotes an oil temperature sensor that outputs information on the oil temperature T _OIL of the hydraulic circuit.

The main parts of the DBWECU 3 and the CVT ECU 21 are both constituted by a microcomputer.
In particular, the built-in storage circuit stores and processes the maps shown in FIGS. 5 to 9 and the shift control programs shown in FIGS. 10 to 12. Here, the target primary pulley rotation speed calculation map in FIG. 5 is used to calculate the target primary pulley rotation speed Wpo during normal operation according to the throttle opening θs (or the accelerator opening θa). The target primary pulley rotational speed (addition) calculation map in FIG. 6 is the target primary pulley rotational speed addition △ W corresponding to the oil temperature T _01L.
Used to calculate po. This goal primary
リ Wpo is the fluidity of oil depending on the oil temperature.
Improved switching response can be increased according to oil temperature.
Wear. The target secondary cylinder oil pressure calculation map shown in FIG. 7 is based on the input torque Te, the gear ratio I, and the vehicle speed V, and shows the target oil pressure Ps.
Used to calculate o. The intake air amount calculation map of FIG. 8 is used to calculate an intake air amount according to the throttle opening θs and the engine speed Ne. The torque calculation map of FIG. 9 shows the intake air amount A / N and the engine speed Ne.
It is used to calculate the input torque Te.

The DBWECU 3 calculates the throttle opening θs according to the accelerator opening θa and the engine speed Ne,
A well-known function of controlling the throttle valve 9 to the throttle opening θs is provided. On the other hand, CVTECU21 the output shaft speed of the continuously variable transmission 20 (the secondary pulley rotational speed W
calculating a deceleration rate [Delta] V of the vehicle on the basis of s), the rate of deceleration as a sudden braking mode determining means | [Delta] V | To determine whether excess of sudden braking mode determination value [alpha] 1. At this time, if the rapid braking mode M2 is set, the line pressure is reduced to the normal line pressure P 1.
Sudden braking line pressure P l 2 was higher than 1, the target primary pulley rotational speed W that is set in accordance with the A Kuseru opening θa
Setting the p o as the target primary pulley speed Wpor for sudden braking by a predetermined amount increase modification. Furthermore, this sudden shake
The target shift speed V is determined based on the deviation E between the target primary pulley rotation speed Wpo and the actual primary pulley rotation speed Wp.
i1 is calculated, the line pressure regulating valve is driven according to the sudden brake line pressure P12, and the speed ratio control valve 54 is switched to switch the primary pulley 26 at the target speed Vi.
A function of supplying a control oil pressure P p in the primary hydraulic actuator 3 3 through.

Hereinafter, a shift control device for a continuously variable transmission according to this embodiment will be described with reference to control programs shown in FIGS. 10 to 13 and a block diagram shown in FIG. In this embodiment,
By operating an ignition key (not shown), the engine body 60 is started, and the DBWE shown in FIGS.
The control in the CU 3 and the CVT ECU 21 is also started.
The DBWECU 3 controls the fuel injection valve 1 associated with the fuel supply amount control.
The driving process of the ignition plug 2, the driving process of the spark plug 2 accompanying the ignition timing control, and the driving process of the throttle valve accompanying the engine output control are executed according to a known program.

On the other hand, the CVT ECU 21 enters the shift control of the continuously variable transmission shown in FIGS.
The rotational speeds Wp and Ws of the primary pulley 26 and the secondary pulley 28, which are detection data of each sensor, and DBW
The accelerator opening θa (or throttle opening θs) from the ECU 3, the engine speed Ne, and the like are fetched and stored in a predetermined area. Step calculates the actual gear ratio of In from the a2,3,4 primary pulley rotation speed Wp and the secondary pulley rotation speed Ws, and calculates the vehicle speed V from the speed reduction ratio r and the secondary pulley rotation speed Ws of the reduction gear 30, the opening The target primary pulley rotation speed Wpo is calculated from θs. Further, in step a5, the secondary pulley rotation speed Ws is differentiated to calculate the absolute value | ΔV | of the deceleration rate, and stores the calculated value in a predetermined area. Further, in step a6, the intake air amount A / N is calculated from the engine speed Ne and the throttle opening θs, the input torque Te is calculated from the intake air amount A / N and the engine speed Ne, and stored in a predetermined area. I do.

Thereafter, the speed change control in step a7 is performed. In shifting speed control processing to achieve the desired primary pulley speed Wpo is, as shown in FIG. 13, in the first step c 1, the corresponding target gear ratio the target primary pulley speed Wpo and the actual primary pulley rotation speed Wp The deviation E (= Wpo-Wp) is obtained, and step c
At 2, a change gain K1 for decreasing the response in accordance with an increase in the engine speed , a change gain K2 for increasing the response in accordance with an increase in the deviation between the actual value and the target value of the primary pulley , and a ratio control gain K. Import 3 Step c 3
Then, the basic shift speed Vi1 is calculated by multiplying the deviation E by the gains K1, K2, and k3. Further, a deviation between the previous value by integrating the basic shift speed Vi1 in step c 4, multiply it to the limiter for preventing diffusion, further obtains the integral correction shift speed ViI by multiplication of the integral correction factor 1 / Z . Then, in step c5, the basic shift speed Vi
1 and the integrated corrected shift speed ViI to calculate the shift speed Vi, and the shift control oil pressure Pc capable of achieving the same shift speed Vi.
Calculating a corresponding duty signal Du to. In step c6 solenoid control valve 23 is driven at a duty signal Du, the electromagnetic control valve 23 outputs a shift control hydraulic pressure Pc, the speed change ratio control valve 54 which receives the transmission control oil pressure Pc is ply
Supplying Mali pulley control pressure Pp in the primary pulleys oil pressure actuator 33, switching the primary pulley 26 at the target speed change rate, and thus to achieve the target speed ratio I.

Thereafter, the brake control processing in step a8 and the control processing associated with other known shifts in step a9 are performed to complete one control processing. Here, step a8
Will be described. As shown in FIG. 11, first, the control mode is determined. In the normal brake mode M1, the process proceeds to Step b2. In the sudden brake control mode M2, the process proceeds to Step b3. In the non-brake normal mode M0, Step b4 is performed. Process to return to routine. In the control mode determination process shown in FIG. 12, first, at step b5, the vehicle speed V is set to a predetermined value, for example, 5
It is determined whether it is lower than 0 km / h and 50 km / h
If it exceeds , the brake flag is cleared at step b6 in order to prevent overspeed of the continuously variable transmission due to a high-speed downshift, and if it is lower than 50 km / h , the process proceeds to step b7.

[0024] The current engine torque is specified value in this case, even if
For example, it is determined whether it is below 0 (Kg · fcm), that is, whether it is during engine braking or not. If it is not engine braking , the brake flag is cleared in step b8, and if it is engine braking, the process proceeds to step b9. In step b9, it is determined whether or not the deceleration rate | ΔV | exceeds the normal brake mode determination value α1 {here (7 km / h) / sec}.
Is the sudden braking mode determination value α2 ｛here (13 km /
determining whether greater than h) / sec}, exceeds the stearyl
Set the abrupt braking control flag in-up b11 regarded as hard braking mode M2, below the step b10
In step, the normal brake control flag is set and the normal brake mode M1 is regarded. Further, the deceleration rate | ΔV | is equal to the normal brake mode determination value α1 {here (7 km / h) / s
ec}, in particular, if it falls below the brake release determination value α3 {here (4 km / h) / sec}, step b1
At 2, the brake flag is cleared and the non-brake mode M0 is regarded. That is, here, as shown in the mode setting map m4 in FIG. 2, the control is performed such that there is a difference in the judgment value between the time of normal braking and the time of sudden braking in the case of going to the judgment of the brake mode and the case of judging whether the brake is released. It is so as not to cause a Han <br/> quenching to.

According to the determination in step b9, step b
At 10, the normal brake flag is set and the normal brake
To reach from step b2 to step b13 when it is regarded as a mode M1. Here, the target secondary pulley pressure
The normal line pressure Pl1 as in the case of the sudden braking mode M2
Equivalent to a higher sudden brake line pressure P12, for example , the maximum value of the line pressure (when the duty ratio to the electromagnetic control valve 40 is 1
00%) and the target primary pulley rotation speed Wpo
Sets the target primary pulley rotation speed Wpo as it is in accordance with the throttle opening θs from the m1 map of FIG. Accordingly, during normal braking, the hydraulic pressure of the secondary cylinder 34 is adjusted to the maximum value, and the secondary pulley can be operated early so that the winding diameter of the belt 27 becomes the maximum value. The winding diameter can be moved to the minimum side early, the slack of the belt is prevented, and the slip between the belt and the pulley is prevented when the vehicle restarts after stopping.

On the other hand, the step b9 determines
In step b11, the sudden brake flag is set and sudden braking is performed.
When the mode M2 is considered, the steps from the step b3 to the step
Susumu free to b 15. Here, the target secondary pulley pressure is set to the maximum value of the line pressure (the duty ratio to the electromagnetic control valve 40 is set to 1).
00%), and outputs the same duty ratio to the electromagnetic control valve 40. In step b16, the provisional target primary pulley rotation speed 1 (Wpo) is normally calculated from the m1 map, and subsequently the oil temperature T _OIL is taken in, as shown in FIG.
Target primary pulley rotational speed 2 ([Delta] W from m2 map was
po) is calculated as an additional amount, and the normal value Wpo and the additional amount ΔWpo are added as the target primary pulley rotation speed, and the corrected value is set as the target primary pulley for abrupt braking.
The rotation speed is calculated as Wpor . Thereafter, step b17
Then, the gain K3 is set to 2 in order to process the shift speed Vi1 twice as usual (see the m5 map in FIG. 2 ).

When the above-described shift speed control process is executed in response to this process, the maximum hydraulic pressure is ensured in the rapid braking mode M2 because the line pressure has a duty ratio of 100%. Revolution W
po r is usually by Redirecting a listen, moreover, the transmission speed is usually 2
Set to double. Therefore, the secondary pulley 28 at the time of sudden braking exits surge a good response wound ratios come,
As a result, the switching in a short time during sudden braking to the target low gear is made to an appropriate probability, occurrence of slack in the belt is prevented.

Next, when each brake flag is cleared in step b12 by the determination in step b9 and the non-brake mode M0 is considered, that is, in the normal operation state, the process proceeds from step b4 to step b18. Here, the target hydraulic pressure Pso of the secondary cylinder 34 is set to the input torque T
e, actual speed ratio In, vehicle speed V, and the like. In this case, the value calculated from the input torque Te and the actual speed ratio In using the m3 map of FIG.
The target oil pressure Pso is determined. As a result, the line pressure that has been rapidly increased at the time of sudden braking can be returned to the normal value. Subsequently, a target primary pulley speed Wpo corresponding to the throttle opening θs step b 19, 20 m1
It is calculated by a map, stored, the ratio control gain K3 is set to 1, and the process returns to the main routine. As a result, in normal operation, the line pressure and the target primary pulley rotation
The number of turns Wpo and the ratio control gain K3 return to normal values, and the durability of the continuously variable transmission is maintained.

[0029]

As described above, the shift control device for a continuously variable transmission according to the present invention detects the deceleration rate of the vehicle, and if the deceleration rate exceeds the sudden brake mode determination value, a sudden brake mode is set. It calculates the number of rotation sudden braking target primary pulley to be added modified according to the line pressure and the oil temperature brake, by driving the line pressure regulating valve in accordance with the sudden brake line pressure, large diameter winding of the secondary pulley Switch
And the target primary pulley speed for sudden braking
Shift based on the deviation between the actual and the actual primary pulley rotation speed
By controlling the shift control valve according to the speed , the primary pulley
Change the winding diameter of. Because of this,
Primary pulley and secondary pulley in a short time
Both can be properly switched to the target full low (high gear ratio)
To prevent belt slack, etc.
Both pulleys are damaged when starting after a stop
Can be prevented. Moreover, the target primary pulley rotation speed
The shift speed is set to a large value by
The gear is switched to the target low gear ratio (Low side) in a short time.
Replacement is performed accurately, preventing belt slack more reliably
Is done . In addition, this target primary pulley rotation speed
By making a correction to the rotation side according to the oil temperature,
Responsiveness of appropriate switching control can be secured . further,
The target primary pulley rotational speed for abrupt braking is set to a large value in accordance with the oil temperature, it is possible to take into consideration the poor return of the actual gear ratio due to the viscosity of the oil, and it is possible to ensure the responsiveness of the switching control appropriate for the oil temperature.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle power transmission system including a shift control device of a continuously variable transmission as one embodiment of the present invention.

FIG. 2 is a functional block diagram of an electronic control unit in the apparatus of FIG.

FIG. 3 is a hydraulic circuit diagram of the continuously variable transmission used by the continuously variable transmission in the apparatus of FIG.

FIG. 4 is a sectional view of a main part of a continuously variable transmission in the apparatus of FIG. 1;

FIG. 5 is a characteristic diagram of a target primary pulley rotation speed calculation map adopted by the electronic control device in the device of FIG. 1;

6 is a characteristic diagram of a target primary pulley rotation speed (addition) calculation map adopted by the electronic control device in the device of FIG. 1;

FIG. 7 is a characteristic diagram of a target hydraulic pressure calculation map of a secondary cylinder employed by the electronic control device in the device of FIG. 1;

FIG. 8 is a characteristic diagram of an intake air amount calculation map adopted by an electronic control unit in the apparatus of FIG. 1;

FIG. 9 is a characteristic diagram of a torque calculation map adopted by an electronic control unit in the apparatus of FIG.

FIG. 10 is a flowchart of a shift control main routine employed by the electronic control unit in the apparatus of FIG.

FIG. 11 is a flowchart of a brake control routine employed by the electronic control unit in the apparatus of FIG. 1;

FIG. 12 is a flowchart of a brake control routine employed by the electronic control unit in the apparatus of FIG. 1;

FIG. 13 is a flowchart of a shift speed control routine employed by the electronic control unit in the apparatus of FIG.

FIG. 14 is a functional block diagram of an electronic control device in a conventional device.

[Explanation of symbols]

12 throttle opening sensor 13 accelerator opening sensor 20 continuously variable transmission 21 CVT ECU 23 electromagnetic control valve 26 primary pulley 27 drive belt 28 secondary pulley 33 primary cylinder 34 secondary cylinder 40 electromagnetic control valve 45 hydraulic actuator 46 hydraulic actuator 48 regulator valve 54 Shift hydraulic pressure control valve Ws Secondary pulley rotation speed Wp Primary pulley rotation speed Wpo Target primary pulley rotation speed Vi Target shift speed E Deviation ΔV Deceleration rate

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI F16H 59:72 F16H 59:72 63:06 63:06 (58) Investigated field (Int.Cl. ⁷ , DB name) F16H 59 / 00-61/12 F16H 61/16-61/24 F16H 63/40-63/48 F16H 9/00

Claims (1)

(57) [Claims] 1. An input shaft primary pulley connected to an engine, an output shaft side secondary pulley connected to a drive shaft, an endless belt stretched between both pulleys, and an endless belt on the primary pulley side. a primary hydraulic actuator for changing the winding diameter of the belt, the shift control device for a vehicle continuously variable transmission comprising a secondary hydraulic actuator for changing the winding only the diameter of the endless belt in the secondary pulley side, in the engine load Target primary pulley rotation speed setting means for setting the target primary pulley rotation speed in accordance with the target primary pulley rotation speed, and controlling the amount of oil supplied to the primary hydraulic actuator in accordance with the target primary pulley rotation speed set by the target primary pulley rotation speed setting device. A shift control valve, Line pressure setting means for setting a line pressure by using a pressure control valve for controlling a hydraulic pressure supplied to the secondary hydraulic actuator according to the line pressure set by the line pressure setting means; and a deceleration rate for detecting a deceleration rate of the vehicle. and detecting means, oil temperature detecting means for detecting the temperature of the primary hydraulic Akuchiyuetahe supplying oil, when the deceleration rate exceeds a predetermined value, a rapid braking state determining means determines that sudden braking state, rapid braking A line pressure correction unit that corrects the line pressure set by the line pressure setting unit to a high pressure side when determined to be in a state, and based on the oil temperature when determined to be in a rapid braking state.
Target primary pulley rotation speed correction means for correcting the set value set by the target primary pulley rotation speed setting means to a higher rotation side; target primary pulley rotation speed corrected by the target primary pulley rotation speed correction means; Target shift speed setting means for setting a target shift speed based on a deviation from a pulley rotation speed; controlling the pressure regulating valve according to the line pressure correction value; and controlling the shift control valve according to the target shift speed. A shift control device for a continuously variable transmission, comprising: shift control means for controlling.