JP4396183B2 - Control device for continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission whose torque capacity changes according to a clamping pressure.

  The belt-type continuously variable transmission and the traction-type continuously variable transmission transmit torque using the frictional force between the belt and the pulley and the shearing force of the traction oil between the disk and the roller. Therefore, the torque capacity of these continuously variable transmissions is set according to the pressure acting on the location where the torque is transmitted.

  The above-mentioned pressure in a continuously variable transmission is referred to as pinching pressure. Increasing the pinching pressure can increase the torque capacity and avoid slipping, but on the other hand, more power than necessary to generate high pressure. There are inconveniences such as consumption or reduction in power transmission efficiency. Therefore, in general, the clamping pressure is set as low as possible within a range in which unintended slip does not occur.

  For example, in a vehicle equipped with a continuously variable transmission, the engine speed can be controlled by the continuously variable transmission to improve fuel efficiency. In order to improve the transmission efficiency as much as possible, the clamping pressure is controlled to be set as low as possible within a range where no slip occurs. For that purpose, it is necessary to detect the pressure at which slipping starts (that is, the slip limit pressure). Conventionally, slip is detected by various methods, and the slip limit pressure is detected.

For example, Patent Document 1 discloses a control device for setting a belt clamping pressure in a belt-type continuously variable transmission, which is in a steady running state in which the vehicle is running at a constant speed on a flat road. A control device configured to allow a decrease in the belt clamping pressure at times, and to cancel the decrease in the belt clamping pressure during unsteady traveling, where acceleration / deceleration is frequently performed or traveling on a rough road Are listed. Japanese Patent Application Laid-Open No. H10-228561 describes an apparatus configured to control a hydraulic pressure (line pressure) related to the belt tension in consideration of a delay in a change in the line pressure.
JP 2003-120804 A JP-A-6-207657

  In the invention of the above-mentioned Patent Document 1, when there is a change in the operating state such as an increase in input torque due to, for example, a sudden depression of the accelerator during the clamping pressure reduction control, the corresponding control delay is large. That is, if the responsiveness is low, the continuously variable transmission may slip. On the other hand, in order to prevent such slipping, considering the variation in the hydraulic system and setting the normal belt clamping pressure on the assumption that the responsiveness is low, the fuel consumption improvement effect by reducing the clamping pressure is sufficient. However, there was still room for improvement in these respects. Further, in the invention of Patent Document 2, the control deviation of the feedback control is merely set so that the delay in the change of the line pressure does not cause the overshoot, and the influence on the other corresponding control due to the delay is set. It cannot be avoided.

  The present invention has been made by paying attention to the above technical problem, and it is possible to set an appropriate clamping pressure by reflecting the response when controlling the clamping pressure of the continuously variable transmission in the control. The object is to provide a control device.

In order to achieve the above object, a first aspect of the present invention provides a control device for a continuously variable transmission that controls a clamping pressure that sets a torque capacity of a continuously variable transmission, and a response of a control mechanism that controls the clamping pressure. and executes the change control for changing the clamping pressure according to a predetermined frequency which is previously set in order to detect the sex, the start command point of the change control until it determines the changes in the actual value for the start command and responsiveness detecting means for detecting the response on the basis of the dead time of the control content setting means for setting the control content of said clamping pressure on the basis of the response detected by the response detection means, the A control apparatus comprising: a clamping pressure control means for controlling the clamping pressure in accordance with the control content set by the control content setting means .

Further, the invention according to claim 2 is the invention according to claim 1 , wherein the control content setting means includes means for selecting a control content for controlling the clamping pressure to a relatively high pressure as the responsiveness is low. This is a control device characterized by that.

Furthermore, the invention of claim 3, wherein in the invention in claim 1, wherein the clamping and feedback control means for controlling to a predetermined target value of pressure, the dead time determined by the response detection means based on a control apparatus characterized by further comprising a gain setting means for setting the gain of the feedback control.

Further, according to a fourth aspect of the present invention, in the third aspect of the present invention, the gain setting means sets the gain of the feedback control to a gain in which the control change amount becomes relatively smaller as the responsiveness is lower. It is comprised so that it may carry out, It is a control apparatus characterized by the above-mentioned.

Therefore, according to the first aspect of the present invention, the responsiveness at the time of controlling the clamping pressure of the continuously variable transmission is detected, and based on the responsiveness, the control content such as permission or prohibition of the clamping pressure reduction control is determined. Set and execute control. Therefore, it is possible to control the clamping pressure with appropriate control content that responds quickly to changes in the driving state and fluctuations in the control of the hydraulic system, and prevents or suppresses the slippage of the continuously variable transmission or The fuel consumption can be improved by setting the pressure as low as possible . Further, when the control content of the clamping pressure is set based on the responsiveness when controlling the clamping pressure of the continuously variable transmission, for example, the reduction control of the clamping pressure or the feedback control of the clamping pressure is performed based on the control content Nipping pressure control is performed. Therefore, the responsiveness can be confirmed prior to the control of the clamping pressure or in the process of executing the control, and the clamping pressure can be controlled with more appropriate control content.

Further, according to the invention of claim 2, when the responsiveness in controlling the clamping pressure of the continuously variable transmission is detected, the level of the responsiveness is judged. The control content to control to a higher pressure, for example, the control content to decrease the reduction amount of the clamping pressure as the responsiveness is lower when the clamping pressure is lowered, is selected and executed. As a result, even when the possibility of slipping occurs in the continuously variable transmission due to the low responsiveness of the clamping pressure control, the clamping pressure is controlled to a relatively high pressure, that is, a pressure on the safe side against the slip. By selecting the control content, the clamping pressure can be controlled, and slippage of the continuously variable transmission can be prevented or suppressed.

Still further, according to the invention of claim 3, the responsiveness at the time of controlling the clamping pressure of the continuously variable transmission is detected, and based on the responsiveness, the gain which is a control constant at the time of feedback control of the clamping pressure Is set, and feedback control is executed. Therefore, appropriate feedback control that reflects the responsiveness of the clamping pressure control in the control can be executed.

Further, according to the invention of claim 4, when the gain is set based on the responsiveness at the time of controlling the clamping pressure and the feedback control is executed, it corresponds to the level of the responsiveness of the clamping pressure control. Since an appropriate gain is set, for example, control hunting that may occur when the responsiveness of the clamping pressure control is low can be prevented, and more appropriate feedback control can be executed.

  Next, the present invention will be described based on specific examples. First, an example of a drive system including a power source and a continuously variable transmission targeted in the present invention will be described. FIG. 4 schematically shows an example of a drive system including a belt-type continuously variable transmission 1. The continuously variable transmission 1 is connected to a power source 5 via a forward / reverse switching mechanism 2 and a fluid transmission mechanism 4 with a lock-up clutch 3.

  The power source 5 is composed of an internal combustion engine, or an internal combustion engine and an electric motor, or an electric motor. In the following description, the power source 5 is referred to as the engine 5. The fluid transmission mechanism 4 has a configuration similar to that of, for example, a conventional torque converter, and includes a pump impeller rotated by the engine 5, a turbine runner disposed to face the pump impeller, and a stator disposed therebetween. The turbine runner is rotated by supplying a spiral flow of fluid generated by a pump impeller to the turbine runner, and torque is transmitted.

  In such torque transmission via the fluid, inevitable slip occurs between the pump impeller and the turbine runner, and this causes a reduction in power transmission efficiency. Therefore, the input member such as the pump impeller and the turbine runner A lock-up clutch 3 that directly connects an output side member such as the above is provided. The lock-up clutch 3 is configured to be controlled by hydraulic pressure, and is controlled to a fully engaged state, a fully released state, and a slip state that is an intermediate state between them, and the slip rotation speed can be appropriately controlled. It has become.

  The forward / reverse switching mechanism 2 is a mechanism that is employed when the rotational direction of the engine 5 is limited to one direction, and outputs the input torque as it is or reversely outputs it. It is configured. In the example shown in FIG. 4, a double pinion type planetary gear mechanism is employed as the forward / reverse switching mechanism 2. That is, a ring gear 7 is arranged concentrically with the sun gear 6, and a pinion gear 8 meshed with the sun gear 6 and the pinion gear 8 and another pinion gear 9 meshed with the ring gear 7 are arranged between the sun gear 6 and the ring gear 7. The pinion gears 8 and 9 are held by the carrier 10 so as to rotate and revolve freely. A forward clutch 11 that integrally connects two rotating elements (specifically, the sun gear 6 and the carrier 10) is provided, and the direction of the torque that is output by selectively fixing the ring gear 7 There is provided a reverse brake 12 that reverses.

  The continuously variable transmission 1 has the same configuration as a conventionally known belt-type continuously variable transmission, and each of a driving pulley 13 and a driven pulley 14 arranged in parallel to each other includes a fixed sheave, a hydraulic type The movable sheave is moved back and forth in the axial direction by the actuators 15 and 16. Therefore, the groove width of each pulley 13 and 14 is changed by moving the movable sheave in the axial direction, and accordingly, the winding radius of the belt 17 wound around each pulley 13 and 14 (the effective diameter of the pulleys 13 and 14). ) Changes continuously, and the gear ratio changes steplessly. The drive pulley 13 is connected to a carrier 10 that is an output element in the forward / reverse switching mechanism 2.

  The hydraulic actuator 16 in the driven pulley 14 is supplied with hydraulic pressure (line pressure or its correction pressure) according to the torque input to the continuously variable transmission 1 via a hydraulic pump and a hydraulic control device (not shown). Yes. Therefore, each sheave in the driven pulley 14 holds the belt 17 so that tension is applied to the belt 17, and a holding pressure (contact pressure) between the pulleys 13, 14 and the belt 17 is ensured. . On the other hand, the hydraulic actuator 15 in the drive pulley 13 is supplied with pressure oil corresponding to the speed ratio to be set, and is set to a groove width (effective diameter) corresponding to the target speed ratio. .

  The driven pulley 14 is connected to a differential 19 through a gear pair 18, and torque is output from the differential 19 to driving wheels 20. Therefore, in the above drive mechanism, the lockup clutch 3 and the continuously variable transmission 1 are arranged in series between the engine 5 and the drive wheels 20.

  Various sensors are provided in order to detect the operation state (running state) of the vehicle on which the continuously variable transmission 1 and the engine 5 are mounted. That is, the turbine speed sensor 21 that detects the input speed (the speed of the turbine runner) to the continuously variable transmission 1 and outputs a signal, and the input speed that detects the speed of the drive pulley 13 and outputs the signal. A sensor 22, an output rotation speed sensor 23 that detects the rotation speed of the driven pulley 14 and outputs a signal, and a hydraulic pressure sensor 24 that detects the pressure of the hydraulic actuator 16 on the driven pulley 14 side for setting the belt clamping pressure are provided. ing. Although not specifically shown, an accelerator opening sensor that detects a depression amount of the accelerator pedal and outputs a signal, a throttle opening sensor that detects a throttle valve opening and outputs a signal, and a brake pedal are depressed. A brake sensor or the like that outputs a signal in case is provided.

  A transmission is used to control the engagement / release of the forward clutch 11 and the reverse brake 12, the control of the clamping force of the belt 17, the control of the transmission ratio, and the control of the lockup clutch 3. An electronic control device (CVT-ECU) 25 is provided. The transmission electronic control unit 25 is configured mainly by a microcomputer as an example, performs calculations according to a predetermined program based on input data and data stored in advance, and performs various operations such as forward, reverse, and neutral. And the required clamping pressure setting, the gear ratio setting, the engagement / release of the lock-up clutch 3, the slip rotation speed, and the like are executed.

  Here, an example of data (signal) input to the transmission electronic control unit 25 is as follows: a signal of the input rotation speed (input rotation speed) Nin of the continuously variable transmission 1 and an output of the continuously variable transmission 1. A signal of the rotation speed (output rotation speed) No is input from the corresponding sensor. An engine electronic control unit (E / G-ECU) 26 for controlling the engine 5 receives a signal of an engine speed Ne, an engine (E / G) load signal, a throttle opening signal, an accelerator pedal (not shown). )), The accelerator opening signal is input.

  According to the continuously variable transmission 1, the engine speed, which is the input speed, can be controlled steplessly (in other words, continuously), so that the fuel efficiency of a vehicle equipped with the engine speed can be improved. For example, the target driving force is obtained based on the required driving amount represented by the accelerator opening and the vehicle speed, and the target output necessary to obtain the target driving force is obtained based on the target driving force and the vehicle speed. The engine speed for obtaining the target output with the optimum fuel consumption is obtained based on a map prepared in advance, and the gear ratio is controlled so as to be the engine speed.

  In order not to impair such an improvement in fuel consumption, the power transmission efficiency in the continuously variable transmission 1 is controlled to a good state. Specifically, the torque capacity of the continuously variable transmission 1, that is, the belt clamping pressure, can transmit the target torque determined based on the engine torque, and the belt clamping pressure is as low as possible without causing the belt 17 to slip. It is controlled to become. For example, the belt clamping pressure controls the continuously variable transmission 1 in a so-called unsteady traveling state such as when acceleration / deceleration is performed relatively frequently or when traveling on a rough road with uneven or uneven road surfaces. It is set to a relatively high pressure such as the line pressure that is the total source pressure in the hydraulic system or its correction pressure.

  On the other hand, in steady running conditions such as running on a flat road at a certain speed or above, or in a quasi-steady running condition equivalent to this, the lowest pressure that can transmit input torque without slipping, that is, the limit clamping pressure In order to detect this, the belt clamping pressure is gradually reduced. The belt clamping pressure is set to a belt clamping pressure obtained by adding a predetermined safety factor or a pressure for setting a margin transmission torque for slipping to the detected limit clamping pressure. The belt clamping pressure in the continuously variable transmission is preferably as low as possible within a range where torque can be transmitted without causing slippage.

  However, if a change occurs in the operating state such as an increase in input torque due to an accelerator depressing operation or the like during a decrease control of the belt clamping pressure, if the responsiveness of the clamping pressure control is low, the belt clamping force corresponding to the increase in input torque The increase in pressure may be delayed, causing belt slip. Also, in order to prevent belt slippage, considering the variation in responsiveness due to the influence of the hydraulic system, etc., assuming that the responsiveness is low and setting the normal belt clamping pressure, the clamping pressure is made as small as possible. There may be a case where the fuel efficiency improvement effect due to the reduction to a low pressure cannot be sufficiently obtained. Therefore, the control device of the present invention is configured so that an appropriate clamping pressure can be set by reflecting in the control the responsiveness when controlling the clamping pressure of the continuously variable transmission. A specific example of the control will be described below.

  FIG. 1 is a flowchart showing an example thereof, and FIG. 2 is a part of a time chart when the control shown in the flowchart is performed. In FIG. 1, first, it is determined whether there is a failure or abnormality in a sensor, a hydraulic actuator, a communication system, etc. (step S10). If there is no failure or abnormality in the sensor, actuator, communication system, etc., and if a positive determination is made in step S10, the process proceeds to step S20, and whether or not the running state is in a steady or quasi-steady running state. Is judged.

  If the traveling state is in a steady or quasi-steady traveling state and the determination in step S20 is affirmative, the process proceeds to step S30, where the oil temperature of the continuously variable transmission 1 and the vehicle speed are within predetermined ranges. It is determined whether or not there is. Within the predetermined range of the oil temperature of the continuously variable transmission 1 is a predetermined temperature range as a range of the oil temperature of the continuously variable transmission 1 in a state where the torque acting on the continuously variable transmission 1 is stable. For example, in order to determine that the warm-up has been completed, the upper limit may be infinite, and the temperature range may be set with only the lower limit on the low temperature side. In addition, the predetermined range of the vehicle speed may be a speed range in which the lower limit on the low speed side is set to 0 km / h and the upper limit of the infrequent super high speed region is set as the range of the vehicle speed that is normally high in frequency.

  If the oil temperature of the continuously variable transmission and the vehicle speed are within the predetermined ranges, respectively, if a positive determination is made in step S30, the process proceeds to step S40, where the vehicle is not traveling on a rough road and the belt It is determined whether or not the slip determination is being performed, and further whether or not the tire slip determination is being performed. That is, in this step S30, it is determined whether there is a disturbance such as road surface input or belt slippage.

  The conditions determined in the above steps S10 to S40 are so-called control start conditions for executing the control shown in this flowchart. Although not shown in this specific example, for example, “the lockup clutch is set to the torque fuse state”, “the shift position is in the drive range, and there is no failure”, and the like are added as control start conditions. You can also.

  If a negative determination is made in any of steps S10 to S40, that is, if the control start condition is not satisfied, the process proceeds to step S130, and a belt clamping pressure return command is output. At this time, if the belt clamping pressure has been reduced, the belt clamping pressure is restored to the normal hydraulic pressure state or increased to a hydraulic pressure-up state such as during unsteady running. If the belt clamping pressure is in the hydraulic pressure up state, step S130 is skipped and the process proceeds to the next step S140.

  In step S140, if the feedback control of the belt clamping pressure has been executed, this feedback control is stopped, the process proceeds to step S150, the trip counter Ct is reset to zero, and the flag F is set to “0”. . Thereafter, this routine is once terminated. If the feedback control of the belt clamping pressure has not been executed, step S140 is skipped, and the process proceeds to step S150 where the trip counter Ct is reset to zero and the flag F is set to “0”. Thereafter, this routine is once terminated.

  If the vehicle is not traveling on a rough road, the belt slip is not being determined, and the tire slip is not being determined, and if the determination in step S40 is affirmative, the process proceeds to step S43, and there is a responsiveness check history. It is judged whether or not. The responsiveness check history is a history of each control from checking the responsiveness when controlling the belt clamping pressure to deciding whether to execute the belt clamping pressure control or its feedback control.

  At the beginning of the control, since there is no history of the responsiveness check, a negative determination is made in step S43, and step S45 is skipped and the process proceeds to step S50 where the flag F is determined. This flag F is set to “1” when a stepping-up command for pinching pressure for determining responsiveness is output in step S60 described later, and is set to “0” in step S150 at the end of this routine. This flag is a flow control flag for preventing the step-up command from being repeatedly output until a predetermined time elapses after the pinching-step step-up command is output.

  On the other hand, if the affirmative determination is made in step S43 due to the history of the responsiveness check, the process proceeds to step S45, and it is determined whether or not the trip counter Ct is equal to or greater than the predetermined value Ct0. Here, the trip means, for example, that the engine 5 has been controlled to start and the vehicle has traveled or has entered a traveling state, and this trip counter Ct is incremented every time the engine 5 is controlled to start. It is a counter.

  Since the trip counter Ct has not reached the predetermined value Ct0 at the beginning of the control, a negative determination is made in step S45, and this routine is temporarily terminated without performing the subsequent control. On the other hand, if the trip counter Ct is equal to or greater than the predetermined value Ct0 and the determination in step S45 is affirmative, the process proceeds to step S50 described above, and the flow control flag F is similarly determined. .

  Thus, by providing the trip counter Ct and comparing and judging the number of trips and the predetermined value Ct0, the frequency of checking the responsiveness of the belt clamping pressure control can be appropriately set to a predetermined value.

  Since the flow control flag F is set to “0” at the beginning of the control, the process proceeds to the next step S60, the flow control flag F is set to “1”, and the clamping pressure step-up command Is output. This step-up of the clamping pressure is different from the clamping pressure increase control by the clamping pressure return command in the above-described step S130, in order to calculate the dead time L that is an evaluation parameter in order to determine the responsiveness of the clamping pressure control. This is an increase (step-up) control of the clamping pressure that is executed at the same time. Therefore, the amount of increase in the pinching force due to this step-up is such that a shift caused by a change in the thrust ratio due to the increase in the pinching pressure is not perceived by the driver, and responsiveness can be determined. Set as small as possible.

  When the clamping pressure step-up command is output in step S60, it is determined whether or not a predetermined time has elapsed (step S70). This predetermined time is a period that is predetermined as a time required to determine the responsiveness of the clamping pressure control, starting from the time when the clamping pressure step-up command is output in step S60 described above. Is set to a period as short as possible. Note that if the flow control flag F is set to “1” in the above-described step S50, it is a state in which the clamping pressure step-up command for calculating the dead time L has already been output. The control of S60 is skipped, and the process proceeds to step S70, and it is similarly determined whether or not a predetermined time has elapsed.

  If the predetermined time has elapsed and the determination in step S70 is affirmative, the process proceeds to step S80, and the clamping pressure for restoring the clamping pressure increased by the clamping pressure step-up command in step S60 described above A return command is output. Subsequently, the dead time L is calculated (step S90). As shown in the time chart of FIG. 2, the dead time L is an estimated line at the time of the non-step-up command determined from the store value before point A, with the point A when the step-up command for pinching pressure is output as point A From S, when the pinching pressure actual hydraulic pressure rises by a predetermined value is point B, it can be expressed as a period indicated between points AB, based on the stored value of the hydraulic sensor from the pinching pressure step-up command point Can be calculated.

  On the other hand, if the predetermined time has not elapsed and a negative determination is made in step S70, the routine is temporarily terminated without performing the subsequent control, and the elapse of the predetermined time is awaited.

  When the dead time L is calculated in step S90, it is determined whether or not the dead time L is equal to or less than a predetermined value L0 that is determined in advance as a reference for determining the responsiveness of the clamping pressure control (S100). If the dead time L is less than or equal to the predetermined value L0 and it is determined affirmative in step S100, that is, if it is determined that the dead time is short and the responsiveness of the clamping pressure control is high, the process proceeds to step S110. Belt clamping pressure reduction control is executed. This belt clamping pressure drop control is a control for setting the belt clamping pressure to the lowest possible pressure without causing belt slip, and the belt clamping pressure at this time is the clamping pressure reduction amount of FIG. As shown in the relationship diagram between the dead time and the dead time, the longer the dead time L, that is, the lower the responsiveness of the clamping pressure control, the lower the amount of reduction.

  When the belt clamping pressure reduction control is executed in step S110, the process proceeds to step S120, and feedback control for setting the belt clamping pressure so as to reach a predetermined hydraulic pressure level determined according to the operating conditions is started. In step S150, the trip counter Ct is reset to zero and the flag F is set to “0”. Thereafter, this routine is once terminated.

In the above-described steps S110 and S120, an example is shown in which feedback control is executed during belt clamping pressure reduction control. However, the order of control in steps S110 and S120 may be changed, and feedback control in step S120. May be performed alone. In this case, if the dead time L is long, control hunting may occur. However, as shown in the above specific example, the dead time L is calculated to prevent hunting and perform appropriate feedback control. The gain of feedback control can also be changed in consideration of the value of time L. That is, the longer the dead time L calculated by the feedback control is carried out to change the direction of the value feedback amount of the feedback gain is reduced, it is possible to prevent hunting of the control.

  On the other hand, if the dead time L is greater than the predetermined value L0 and a negative determination is made in step S100, that is, if it is determined that the dead time L is long and the responsiveness of the clamping pressure control is low, the process proceeds to step S130. Then, the subsequent control is executed in the same manner as in the case where a negative determination is made in any of the aforementioned steps S10 to S40, and then this routine is temporarily terminated.

  As described above, according to the control device of the present invention configured to execute the control shown in FIGS. 1 to 3, the belt clamping pressure is stepped up to determine the responsiveness when controlling the clamping pressure. The dead time L is calculated as the evaluation parameter. Depending on the level of responsiveness, the clamping pressure return / increase control, the clamping pressure reduction control in which the amount of reduction is appropriately changed, or the clamping pressure feedback control in which an appropriate feedback gain is set are executed. . As a result, by accurately detecting the responsiveness when controlling the clamping pressure and reflecting the responsiveness in the control, it is possible to execute appropriate clamping pressure control and prevent slippage of the continuously variable transmission or The fuel consumption can be improved by suppressing or setting the pinching pressure as low as possible.

  Here, the relationship between each of the above specific examples and the present invention will be briefly described. The functional means of steps S60, S90, and S100 described above serve as the responsiveness detecting means in the inventions of claims 1 and 2. Equivalent to. Each functional means of steps S110 to S140 corresponds to the control content setting means in the invention of claim 1, and among these, the functional means of step S110 is the control content setting means in the invention of claim 3. It corresponds to. And each functional means of step S110 thru | or S140 is equivalent to the clamping pressure control means in this invention of Claim 4. Furthermore, each functional means of steps S120 and S140 corresponds to the feedback control means and the gain setting means of claim 5.

  Note that the present invention is not limited to the above specific example, and can be applied to a control device for a traction type continuously variable transmission in addition to a belt type continuously variable transmission. In the above specific example, the dead time L is calculated and used as an evaluation parameter for determining the responsiveness when controlling the clamping pressure. However, a time constant may be calculated and used. In the above specific example, the determination of the responsiveness is performed once. However, for example, the squeezing pressure step-up command in step S60 is output a plurality of times, and the responsiveness is determined based on the dead time or time constant calculated for each. The determination may be performed a plurality of times. Furthermore, the determination of the responsiveness may be performed prior to the execution of the clamping pressure control and the feedback control of the clamping pressure, or may be performed in the process in which those controls are executed. In other words, the good responsiveness when controlling the clamping pressure may be the execution condition or start condition of the clamping pressure reduction control or the clamping pressure feedback control.

It is a flowchart for demonstrating an example of control by the control apparatus of this invention. 7 is a time chart for explaining an example of a dead time detection method in the control by the control device of the present invention. In the control by the control apparatus of this invention, it is a figure which shows the relationship between the clamping pressure fall amount and dead time for demonstrating an example of the calculation method of the clamping pressure fall amount. It is a figure which shows typically an example of the drive system containing the continuously variable transmission made into object by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Continuously variable transmission, 3 ... Lock-up clutch, 5 ... Engine (power source), 13 ... Drive pulley, 14 ... Driven pulley, 15, 16 ... Hydraulic actuator, 17 ... Belt, 20 ... Drive wheel, 25 ... Shift Electronic control unit for machine (CVT-ECU).

Claims (4)

In the control device for a continuously variable transmission that controls the clamping force that sets the torque capacity of the continuously variable transmission,
And executes the change control for changing the clamping pressure according to a predetermined frequency of the response is preset in order to detect the control mechanism for controlling the clamping pressure, the starting start command point of the change control and responsiveness detecting means for detecting the response on the basis of the dead time until determining the change in the actual value with respect to the command,
Control content setting means for setting the control content of the clamping pressure based on the responsiveness detected by the responsiveness detection means ;
A clamping pressure control means for controlling the clamping pressure in accordance with the control content set by the control content setting means;
Control device for a continuously variable transmission, characterized in that it comprises a. Before SL control content setting hand stage, the lower the pre-Symbol responsiveness, no according to claim 1, characterized in that it comprises means you select the control contents for controlling the clamping pressure to a relatively high pressure Control device for step transmission. And feedback control means for controlling the pre bellflower pressure to a predetermined target value,
Gain setting means for setting a gain of the feedback control based on the dead time determined by the responsiveness detection means;
Control device for a continuously variable transmission according to claim 1, characterized in that you are further provided with. Before SL gain setting means, the lower the response, the gain of the feedback control, to claim 3, the variation of control is characterized in that it is configured to set to a relatively small gain The control device of the continuously variable transmission described.

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