JP2007057073A - Control device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deterioration of drivability while suppressing the occurrence of belt slip when a sudden change in gear ratio is executed.
When it is detected that a sudden downshift is executed (YES in S100), the ECT_ECU performs an upper limit guard on a control value output to a solenoid valve that controls the hydraulic pressure of the input side pulley. Step (S102), a predetermined time elapses after execution of the sudden downshift is detected (YES in S104), or the engine speed is equal to or higher than a predetermined speed α (S106). If the input side pulley hydraulic pressure is equal to or higher than a predetermined hydraulic pressure β (YES in S108), the program is executed including the step of ending the upper limit guard (S110).
[Selection] Figure 4

Description

  The present invention relates to a control device for a continuously variable transmission, and more particularly to control of a gear ratio at a sudden shift.

  Conventionally, in a vehicle equipped with a continuously variable transmission, the speed ratio is feedback controlled so that the actual input rotational speed of the continuously variable transmission matches the set target input rotational speed according to the state of the vehicle. . In the belt-type continuously variable transmission, the effective engagement diameter of the endless belt wound around the pulley is changed by changing the groove width of the pulley by hydraulic pressure, and the gear ratio is controlled. In a vehicle equipped with such a belt-type continuously variable transmission, a downshift of the gear ratio is stepped down during transient shift control when the driver greatly depresses the accelerator or when the driver operates the shift lever. When the gear ratio is suddenly changed as in manual shift control that is executed manually, the hydraulic pressure of the input pulley may drop rapidly. In particular, when the engine is running at a low speed, the discharge pressure of the hydraulic pump is low, the belt torque transmission capacity is insufficient, and the belt may slip.

  In view of such a problem, for example, Japanese Patent Application Laid-Open No. 2001-304389 (Patent Document 1) discloses a shift control device for a belt-type continuously variable transmission that can prevent belt slip due to a sudden change in a gear ratio. To do. The speed change control device includes a primary pulley, a secondary pulley, and an endless belt wound around both pulleys. The transmission control device includes a transmission ratio control unit that controls a transmission ratio between the primary pulley and the secondary pulley, a transmission speed detection unit that detects a transmission speed, and a predetermined speed that is detected in advance by the transmission speed detected by the transmission speed detection unit. And a transmission speed suppression means for suppressing the transmission speed by suppressing the progress of the transmission ratio control by the transmission ratio control means.

According to the speed change control device disclosed in the above-mentioned publication, when the speed change speed exceeds a predetermined value, the progress of the speed ratio control is suppressed, so that the speed change speed is reduced to prevent a sudden speed change. Has the advantage that belt slip is reliably prevented
JP 2001-304389 A

  However, if the progress of the speed ratio control is suppressed until the speed control is completed as in the speed change control device disclosed in the above publication, the progress of the speed ratio control may be unnecessarily suppressed. In other words, in the latter part of the shift control when the engine speed increases and the line pressure and the input-side pulley hydraulic pressure increase sufficiently to prevent slippage, the progress of the gear ratio control is suppressed in the same way as in the initial stage of the shift control. If this is done, the time from the start of shifting to the completion becomes longer, and drivability may deteriorate.

  The present invention has been made to solve the above-described problem, and its object is to suppress the deterioration of drivability while suppressing the occurrence of belt slip when a sudden change in the gear ratio is performed. A control device for a continuously variable transmission is provided.

  A control device for a continuously variable transmission according to a first invention is mounted on a vehicle and changes an effective engagement diameter of an endless belt wound around a pulley by changing a groove width of the pulley by a hydraulic pressure generated by a hydraulic power source. This is a control device for a belt-type continuously variable transmission that changes and controls the gear ratio. When the gear ratio is increasing, the effective engagement diameter of the input pulley is reduced. The control device includes a detecting means for detecting whether or not a sudden change in the gear ratio is executed, and a gear ratio limit for restricting the change in the gear ratio when a sudden change is detected. The restriction is released based on any one of the means, the state detection means for detecting the state of the oil pressure of the oil pressure source and the oil pressure of the input side pulley, and the oil pressure of the oil pressure source and the oil pressure of the input side pulley. And release means.

  According to the first aspect of the invention, the speed ratio limiting means may be stepped by a sudden change in the speed ratio (for example, by a transient speed change control that suddenly increases the speed ratio in response to a sudden increase in the accelerator opening or a shift operation by the driver. When it is detected that the manual transmission control for changing the transmission ratio is executed, the change in the transmission ratio is limited. The release means releases the restriction based on the state of either the hydraulic pressure of the hydraulic power source or the hydraulic pressure of the input side pulley. For example, when a hydraulic source (for example, a hydraulic pump) is driven by a power source (for example, an engine), the hydraulic pressure of the hydraulic source increases as the engine speed increases. For this reason, if the speed of the engine is equal to or higher than a predetermined speed at which a hydraulic pressure source can secure a hydraulic pressure at which belt slip does not occur, the restriction of the gear ratio is released, while suppressing the occurrence of belt slip. As compared with the case where the limit is maintained until the shift control is completed, the shift time can be shortened. Therefore, deterioration of drivability can be suppressed. Therefore, it is possible to provide a control device for a continuously variable transmission that suppresses the deterioration of drivability while suppressing the occurrence of belt slip when a sudden change in the gear ratio is executed.

  The control device for a continuously variable transmission according to the second invention further includes means for detecting the gear ratio of the continuously variable transmission in addition to the configuration of the first invention. The detection means includes means for detecting that a sudden change is executed when the speed of change of the gear ratio is equal to or higher than a predetermined speed.

  According to the second invention, the detecting means detects that a sudden change in the gear ratio is executed when the detected speed of change in the gear ratio is equal to or higher than a predetermined speed. For example, the continuously variable transmission is controlled so that the gear ratio is increased when the accelerator opening is increased by the driver operating the accelerator pedal. As the accelerator opening increases, the gear ratio is rapidly changed at a higher speed. Therefore, it is possible to detect whether or not a sudden change in the gear ratio is executed by detecting whether or not the gear speed of the gear ratio is equal to or higher than a predetermined speed.

  In addition to the configuration of the first invention, the control device for the continuously variable transmission according to the third invention includes means for calculating the target input rotational speed of the continuously variable transmission based on the running state of the vehicle, Means for controlling the continuously variable transmission is further included so that the target input rotational speed matches the actual input rotational speed of the continuously variable transmission. The detecting means includes means for detecting that a sudden change is executed when the difference between the target input rotational speed and the actual input rotational speed of the continuously variable transmission is equal to or greater than a predetermined value.

  According to the third invention, the detecting means detects that a sudden change in the gear ratio is executed if the difference between the target input speed and the actual input speed of the continuously variable transmission is equal to or greater than a predetermined value. To do. For example, the target input rotation speed is set to be increased when the accelerator opening is increased by the operation of the accelerator pedal by the driver. If the difference between the actual input rotational speed and the target input rotational speed is large, a rapid change in the gear ratio with a high shift speed is performed. Accordingly, whether or not a sudden change in the gear ratio is executed by detecting whether or not the difference between the target input speed and the actual input speed is equal to or greater than a predetermined value corresponding to the sudden change. Can be detected.

  In the continuously variable transmission control device according to the fourth aspect of the invention, in addition to the configuration of any one of the first to third aspects, the state detecting means detects the rotational speed of the power source that varies the hydraulic pressure of the hydraulic source. Including a rotation speed detecting means. The releasing means includes means for releasing the restriction when the detected rotation speed is equal to or higher than a predetermined rotation speed.

  According to the fourth aspect of the invention, when the engine speed is equal to or higher than a predetermined speed that can ensure a hydraulic pressure at which no belt slip occurs in the hydraulic power source, belt slippage is generated by canceling the speed ratio control. The shift time can be shortened as compared with the case where the limit is maintained until the shift control is completed while suppressing the shift. Therefore, deterioration of drivability can be suppressed.

  In the continuously variable transmission control apparatus according to the fifth aspect of the invention, in addition to the configuration of any one of the first to third aspects, the state detection means includes a hydraulic pressure detection means for detecting the hydraulic pressure of the input side pulley. Including. The releasing means includes means for releasing the restriction when the detected oil pressure is equal to or higher than a predetermined oil pressure.

  According to the fifth invention, when the hydraulic pressure of the input pulley is equal to or higher than a predetermined hydraulic pressure at which no belt slip occurs, the speed change control is performed while suppressing the occurrence of the belt slip by releasing the speed ratio restriction. The shift time can be shortened compared to the case where the limit is maintained until completion. Therefore, deterioration of drivability can be suppressed.

  In the continuously variable transmission control device according to the sixth aspect of the invention, in addition to the configuration of any one of the first to fourth aspects, the continuously variable transmission is provided with an electromagnetic valve for controlling the hydraulic pressure of the input side pulley. It is done. The state detection means includes means for detecting the control value of the electromagnetic valve. The release means includes means for releasing the restriction when the detected control value is a control value corresponding to a hydraulic pressure equal to or higher than a predetermined hydraulic pressure in the input pulley.

  According to the sixth invention, if the control value of the solenoid valve that controls the oil pressure of the input side pulley is a control value corresponding to a predetermined oil pressure or more that does not cause belt slip in the input side pulley, By canceling the ratio control, the shift time can be shortened as compared with the case where the limit is maintained until the shift control is completed while the occurrence of the belt slip is suppressed. Therefore, deterioration of drivability can be suppressed.

  In the control device for a continuously variable transmission according to the seventh invention, in addition to the configuration of any one of the first to sixth inventions, the release means is predetermined after detecting that a sudden change is executed. Means for releasing the restriction when the specified time has elapsed.

  According to the seventh aspect of the present invention, the restriction is released after a predetermined time has elapsed after the detection of a sudden change in the transmission gear ratio, which can ensure the hydraulic pressure at which no belt slip occurs in the input pulley. Thus, the shift time can be shortened as compared with the case where the limit is maintained until the shift control is completed while the occurrence of the belt slip is suppressed. Therefore, deterioration of drivability can be suppressed.

  In the continuously variable transmission control device according to the eighth invention, in addition to the configuration of any one of the first to seventh inventions, the continuously variable transmission is provided with an electromagnetic valve for controlling the hydraulic pressure of the input side pulley. It is done. The speed ratio limiting means includes means for limiting a control value for the electromagnetic valve during downshifting.

  According to the eighth invention, the gear ratio limiting means limits the control value for the electromagnetic valve at the time of downshift. Thereby, the belt slip which generate | occur | produces when the oil_pressure | hydraulic of the input side pulley at the time of the sudden change of a gear ratio falls rapidly can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a power train of a vehicle including a control device according to the present embodiment will be described. The control apparatus according to the present embodiment is realized by ECT (Electronic Controlled Automatic Transmission) _ECU (Electronic Control Unit) 900 shown in FIG.

  As shown in FIG. 1, the power source 100 is connected to the speed change mechanism 200, and the output shaft 300 of the speed change mechanism 200 is connected to the left and right drive wheels 500 via the differential gear 400. Here, the power source 100 includes various power sources that can be used in the vehicle, such as an internal combustion engine such as a gasoline engine or a diesel engine, or an electric motor such as a motor, and a device that combines the internal combustion engine and the electric motor. In the following description, as a power source 100, fuel is directly injected into a cylinder, and a so-called direct injection gasoline engine capable of homogeneous combustion or stratified combustion is controlled by controlling the injection amount and timing, or the throttle opening is electrically An example in which a gasoline engine equipped with an electronic throttle valve that can be freely controlled will be described (hereinafter, the power source 100 will be referred to as the engine 100).

  The engine 100 is configured to be electrically controllable, and an engine ECU 800 mainly including a microcomputer for the control is provided. The engine ECU 800 is configured to control at least the output of the engine 100, and the output shaft rotational speed (engine rotational speed) NE and the requested output amount such as the accelerator opening PA are input as data for the control. Is done.

  This required output amount is a signal for increasing / decreasing the output of the engine 100, and the operation amount signal of the acceleration / deceleration operation device 700 such as an accelerator pedal operated by the driver and the operation amount are electrically processed. The obtained signal can be used, and in addition, it may be an output request amount signal from a cruise control system (not shown) for maintaining the vehicle speed at the set vehicle speed.

  The transmission mechanism 200 includes a fluid transmission mechanism 210, a forward / reverse switching mechanism 220, and a belt type continuously variable transmission (CVT) 230.

  The fluid transmission mechanism 210 is a device configured to transmit torque between an input-side member and an output-side member via a fluid such as oil, and is adopted as an example in a general vehicle. A torque converter can be mentioned. The fluid transmission mechanism 210 includes a lockup clutch 212. That is, the lock-up clutch 212 is a clutch configured to directly connect the input side member and the output side member by mechanical means such as a friction plate, and is an elastic body such as a coil spring for buffering. The damper 214 which consists of is provided.

  A hydraulic pump that is rotated by the engine 100 as a power source and has a discharge pressure that increases in accordance with the rotational speed is provided at a position close to the fluid transmission mechanism 210. Specifically, it is disposed between the fluid transmission mechanism 210 and the forward / reverse switching mechanism 220. When the fluid transmission mechanism 210 is provided in order to keep the engine 100 driven even when the vehicle is stopped, the automatic clutch that is automatically engaged and disengaged based on the state of the vehicle is The fluid transmission mechanism 210 can be used as a replacement.

  An input member of fluid transmission mechanism 210 is connected to an output member of engine 100, and an output member of fluid transmission mechanism 210 is connected to an input member of forward / reverse switching mechanism 220. This forward / reverse switching mechanism 220 is constituted by a double pinion type planetary gear mechanism as an example, and although not particularly shown, either one of the sun gear and the carrier is used as an input element and the other is used as an output element, and a ring gear is used. A brake element for selectively fixing, and a clutch element for integrating the entire planetary gear mechanism by selectively connecting any two rotating elements of the sun gear, the carrier, and the link gear. . That is, the forward state is set by engaging the clutch element, and the reverse state is set by engaging the brake element.

  A belt type continuously variable transmission 230 shown in FIG. 1 is a belt capable of continuously (continuously) changing the ratio of the rotation speed of the input side member and the rotation speed of the output side member, that is, the gear ratio. Type continuously variable transmission. An example of the belt type continuously variable transmission 230 will be described with reference to FIG.

  A driving pulley (also referred to as a primary pulley or an input pulley) 232, a driven pulley (also referred to as a secondary pulley or an output pulley) 234, and a belt 236 wound around these pulleys 232 and 234 are provided. . Each of the pulleys 232 and 234 includes a fixed sheave 238 and 240 and movable sheaves 242 and 244 that approach and separate from the fixed sheave 238 and 240. The movable sheaves 242 and 244 are fixed to the fixed sheaves 238 and 240. Are provided with hydraulic actuators 246 and 248 for pressing in the direction of approaching. These sheaves 238, 240, 242, and 244 form a V-groove belt winding groove (pulley groove) for winding the belt 236.

  A primary pulley 232 is attached to the input shaft 290, and a secondary pulley 234 is attached to the output shaft 300 disposed in parallel with the input shaft 290. The hydraulic actuator 248 in the secondary pulley 234 is supplied with hydraulic pressure corresponding to the required driving force obtained based on the output request typified by the accelerator pedal opening PA, and presses the movable sheave 244 toward the fixed sheave 240 side. By sandwiching the belt 236, tension necessary to transmit torque is applied to the belt 236.

  In addition, hydraulic oil is supplied to and discharged from the hydraulic actuator 246 of the primary pulley 232 so as to obtain a gear ratio that matches the rotational speed of the input shaft 290 with the target input rotational speed. That is, by changing the groove width (interval between the fixed sheaves 238 and 240 and the movable sheaves 242 and 244) in the pulleys 232 and 234, the wrapping radius (effective engagement diameter) of the belt 236 with respect to the pulleys 232 and 234 is changed. Shifting is executed by changing the size.

  More specifically, the shift is executed by feedback-controlling the hydraulic oil of the primary pulley 232 based on the rotational speed deviation (control deviation) between the actual input rotational speed and the target input rotational speed, and thus the control deviation is large. The faster the speed is changed.

  With reference to FIG. 3, a hydraulic circuit that performs shift control will be described. The supply and discharge of hydraulic oil to and from the primary pulley 232 is performed by flow control. The valve mechanism for that purpose is configured as shown in FIG. That is, the hydraulic actuator 246 of the primary pulley 232 communicates with the first flow control valve 3100 that supplies the line pressure PL and the second flow control valve 3200 connected to the drain.

  The first flow control valve 3100 is a valve for executing an upshift, and a flow between the input port 3300 to which the line pressure PL is supplied and the output port 3400 communicated with the hydraulic actuator 246 of the primary pulley 232. The road is configured to be opened and closed by a spool 3500. A spring 3600 is disposed at one end of the spool 3500, and a first signal pressure port 3700 for applying a signal pressure is formed at an end opposite to the spring 3600 across the spool 3500. Yes. In addition, a second signal pressure port 3800 for applying a signal pressure to the one end side where the spring 3600 is disposed is formed.

  The first solenoid valve 3900 whose output pressure increases according to the duty is connected to the first signal pressure port 3700, and the second solenoid valve whose output pressure increases according to the duty is connected to the second signal pressure port 3800. 4000 is connected to each of the signal pressure ports 3700 and 3800 so that the signal pressure output from the solenoid valves 3900 and 4000 is applied thereto. That is, by increasing the hydraulic pressure applied to the first signal pressure port 3700 and opening the input port 3300, hydraulic oil is supplied from the output port 3400 to the hydraulic actuator 246 of the primary pulley 232, and the groove width of the primary pulley 232 is narrowed. As a result, the gear ratio is lowered. That is, it is upshifted. Further, by increasing the supply flow rate of hydraulic oil at that time, the speed change speed is increased.

  The second flow rate control valve 3200 is a valve for performing a downshift, and the first port 4100 communicated with the hydraulic actuator 246 of the primary pulley 232 is regulated by using the line pressure PL as a source pressure. The spool 4400 is configured to selectively communicate with the second port 4200 to which hydraulic pressure is supplied and the drain port 4300. A spring 4500 is disposed on one end of the spool 4400, and a first signal pressure port 4600 for applying a signal pressure is formed on the one end. A second signal pressure port 4700 for applying a signal pressure is formed at the end opposite to the spring 4500 across the spool 4400.

  The first solenoid valve 3900 is connected to the first signal pressure port 4600, and the second solenoid valve 4000 is connected to the second signal pressure port 4700. These solenoid valves are connected to the signal pressure ports 4600 and 4700, respectively. A signal pressure output by 3900, 4000 is applied. That is, by increasing the hydraulic pressure applied to the second signal pressure port 4700 and causing the first port 4100 to communicate with the drain port 4300, hydraulic oil is discharged from the hydraulic actuator 246 of the primary pulley 232, and the groove width of the primary pulley 232. As a result, the transmission ratio increases. That is, it is downshifted. Further, by increasing the discharge flow rate of the hydraulic oil at that time, the speed change speed is increased.

  Further, a pressure regulating valve 4800 is connected to the second port 4200 of the second flow control valve 3200. This pressure regulating valve 4800 has an input port 5100 to which a line pressure PL is supplied formed on the front side of the piston 5000 pressed by a spring 4900, and an output port communicating with the front side and the back side of the piston 5000. The output port 5200 communicates with the second port 4200 of the second flow rate control valve 3200. Further, the line pressure PL is supplied to the input port 5100 through a double orifice 5300 having a small opening area. That is, the pressure regulating valve 4800 is configured such that a hydraulic pressure having a pressure obtained by subtracting the elastic force of the spring 4900 from the line pressure PL is generated at the output port 5200, that is, the second port 4200 of the second flow rate control valve 3200.

  In the belt-type continuously variable transmission 230, the speed ratio on the lowest speed side (maximum speed ratio: maximum speed ratio: with the belt 236 having a minimum radius of wrapping around the primary pulley 232 and the belt 236 having a maximum radius of wrapping around the secondary pulley 234 On the other hand, the belt 236 has a maximum wrapping radius with respect to the primary pulley 232 and a minimum wrapping radius with the belt 236 with respect to the secondary pulley 234. Ratio (minimum transmission ratio: maximum speed increase state) is set.

  Control of each state of engagement / release of the lockup clutch 212 in the transmission mechanism 200 and half-engagement with slipping, switching of the forward / reverse movement in the forward / reverse switching mechanism 220, and the transmission ratio of the belt-type continuously variable transmission 230 The control is basically performed based on the running state of the vehicle. An ECT (Electronically Controlled Automatic Transmission) _ECU 900 mainly composed of a microcomputer is provided for the control.

  The ECT_ECU 900 is connected to the above-described engine ECU 800 so as to be able to perform data communication. On the other hand, as data for control, the ECT_ECU 900 is input to the vehicle speed, the input side rotational speed (input rotational speed NIN) and the output side rotational speed (output rotational speed) The number NOUT) is input. The rotation speed sensor 600 is a sensor that detects the rotation speed of the primary pulley 232, the secondary pulley 234, and the like in order to execute the shift control in the belt-type continuously variable transmission 230. The pulse gear teeth (not shown) pass through each other to generate a pulse signal in the electromagnetic pickup, and the above-mentioned input rotation speed NIN and output rotation speed NOUT are obtained on the basis of the interval and pulse width of the pulse signal. Configured as follows.

  The transmission mechanism 200 is automatically set in accordance with the stopped state (parking position: P position), reverse state (reverse position: R position), neutral state (neutral position: N position), and the running state of the vehicle. Automatic forward state (drive position: D position) for normal travel, manual forward state for travel by changing the gear ratio stepwise according to the driver's operation, and pumping loss of engine 100 as braking force There is provided a shift device 1000 that selects each state (position) of a state (brake position: B position) and a state (SD position) that prohibits setting of a high speed side gear ratio that is not less than a predetermined value. Are electrically connected to the ECT_ECU 900.

  In the belt-type continuously variable transmission 230 having the above-described configuration, a transient shift control (or linear shift control) that suddenly increases the gear ratio is performed when the driver depresses the accelerator pedal greatly. At this time, the gear ratio changes abruptly (increases rapidly). Alternatively, in the manual shift mode of the belt-type continuously variable transmission 230, when manual shift control for changing the gear ratio stepwise by the driver's operation is performed, for example, when the driver requests a downshift, Since the gear ratio is changed step by step, the gear ratio changes suddenly (abrupt increase).

  The ECT_ECU 900 sets the upper limit guard to the control value output to the second solenoid valve 4000 so that the hydraulic pressure supplied to the input-side pulley 232 does not drop suddenly when the shift control as described above is executed. To implement. That is, the control value is limited so as not to exceed a predetermined upper limit value. This is because, particularly when the engine speed is low, the discharge pressure of the hydraulic pump is low, and when the oil pressure of the input pulley 232 drops rapidly, the belt torque transmission capacity is insufficient and belt slippage occurs. is there.

  However, if the upper limit guard is implemented until the shift control is completed, the shift control may be unnecessarily limited. That is, in the latter stage of the shift control in which the engine speed is increased and the discharge pressure (line pressure) of the hydraulic pump and the hydraulic pressure of the input pulley 232 are increased to the hydraulic pressure at which belt slip does not occur, the above-described upper limit guard is If implemented, the increase in the shift speed is suppressed, and the drivability may be deteriorated by increasing the time from the start to the end of the shift.

  Therefore, according to the present invention, when the ECT_ECU 900 detects that the gear ratio is suddenly changed, the restriction by the upper limit guard is canceled based on the state of either the discharge pressure of the hydraulic pump or the hydraulic pressure of the input pulley 232. It is characterized in that

  Specifically, when the ECT_ECU 900 detects that a sudden change in the gear ratio due to a transient gear shift control or a manual gear shift control is executed, a control value (downshift duty value) output to the second solenoid valve 4000 is detected. (1) Elapse of a predetermined time since it was detected that a sudden change is performed, (2) The engine speed is equal to or higher than a predetermined speed α, (3) When the hydraulic pressure of the hydraulic actuator 246 in the input pulley 232 satisfies any one of the predetermined hydraulic pressures β or more, the upper limit guard is terminated.

  Hereinafter, with reference to FIG. 4, a control structure of a program executed by ECT_ECU 900 that is the control device for continuously variable transmission according to the present embodiment will be described.

  In step (hereinafter, step is described as S) 100, ECT_ECU 900 detects whether or not a sudden downshift is executed. The ECT_ECU 900 may detect, for example, the accelerator opening and the vehicle speed, and detect whether or not a sudden downshift is performed by transient shift control (or linear shift control). For example, when the ECT_ECU 900 detects an increase in the accelerator opening when the vehicle speed is low, the ECT_ECU 900 detects that an abrupt downshift (a sudden change in the gear ratio) is executed by the transient gear shift control.

  Alternatively, the ECT_ECU 900 detects a driver's shift operation on the shift device 1000 in the manual shift mode, and detects whether or not a sudden downshift (a sudden change in the gear ratio) is performed by manual shift control. May be. For example, the ECT_ECU 900 detects that a sudden downshift is performed when an operation for changing the shift stage to the downshift side is performed by the driver's shift operation.

  Alternatively, the ECT_ECU 900 may detect that the sudden downshift is executed when the change amount of the gear ratio (shift speed) is equal to or higher than a predetermined speed, or may be detected by the rotation speed sensor 600. If the difference between the actual input rotational speed and the target input rotational speed set based on the accelerator opening and the vehicle speed is equal to or greater than a predetermined value, it may be detected that a sudden downshift is executed. . If it is detected that a sudden downshift is performed (YES in S100), the process proceeds to S102. Otherwise (NO in S100), this process ends.

  In S102, ECT_ECU 900 performs upper limit guard on the control value (that is, shift duty value) output to second solenoid valve 4000. Specifically, if the shift duty value calculated according to the deviation between the actual input speed and the target input speed is smaller than the upper limit guard value, ECT_ECU 900 uses the calculated shift duty value as a shift command value. If the calculated shift duty value is greater than or equal to the upper limit guard value, the upper limit guard value is output to the second solenoid valve 4000 as a shift command value.

  In S104, ECT_ECU 900 determines whether or not a predetermined time has elapsed after detecting that a sudden change in the gear ratio is executed. The predetermined time is not particularly limited as long as the hydraulic pressure supplied from the hydraulic pump or the hydraulic pressure of the input side pulley 232 can secure the hydraulic pressure at which belt slip does not occur. Be adapted. If the predetermined time has elapsed (YES in S104), the process proceeds to S110. If not (NO in S104), the process proceeds to S106.

  In S106, ECT_ECU 900 determines whether or not the engine speed is equal to or higher than a predetermined speed α. For example, ECT_ECU 900 determines whether or not the engine speed is equal to or higher than a predetermined speed α based on a detection signal representing the engine speed detected by a crank position sensor (not shown). The predetermined rotational speed α is not particularly limited as long as the hydraulic pressure supplied by the hydraulic pump is equal to or higher than the hydraulic pressure at which belt slip does not occur, and is adapted by experiment or the like. . If the engine speed is equal to or higher than a predetermined speed α (YES in S106), the process proceeds to S100. If not (NO in S106), the process proceeds to S108.

  In S108, ECT_ECU 900 determines whether or not the hydraulic pressure of input pulley 232 is equal to or higher than a predetermined hydraulic pressure β. The ECT_ECU 900 may directly detect the hydraulic pressure of the input pulley 232 using a hydraulic sensor or the like to determine whether the hydraulic pressure of the input pulley 232 is equal to or higher than a predetermined hydraulic pressure β. It may be determined whether the control value output to the second solenoid valve 4000 is a control value corresponding to a hydraulic pressure equal to or higher than a predetermined hydraulic pressure β in the input pulley 232. The predetermined hydraulic pressure β is not particularly limited as long as it is equal to or higher than the hydraulic pressure at which belt slip does not occur in the input pulley 232, and is adapted by experiment or the like. If the oil pressure of input side pulley 232 is equal to or higher than a predetermined oil pressure β (YES in S108), the process proceeds to S110. If not (NO in S108), the process proceeds to S102.

  In S110, ECT_ECU 900 ends the upper limit guard for the control value output to second solenoid valve 4000. That is, ECT_ECU 900 outputs a shift duty value calculated according to the difference between the actual input rotation speed and the target rotation speed to second solenoid valve 4000 as a shift command value.

  The operation of ECT_ECU 900, which is a control device for continuously variable transmission according to the present embodiment based on the above-described structure and flowchart, will be described with reference to FIG.

  As shown in FIG. 5 (A), when the driver increases the accelerator opening to AC (1) at time T (0), it is detected that a sudden change in the gear ratio is executed (S100). At YES). As shown in FIG. 5 (B), when the target input rotational speed Ne (0) increases to Ne (1), the difference from the actual input rotational speed increases, as shown in FIG. 5 (C). Furthermore, the shift duty value (control value) for the second solenoid valve 4000 increases. At this time, the shift duty value γ (1) is calculated according to the difference between the actual input rotational speed and the target input rotational speed, but the upper limit guard is implemented by detecting the execution of a sudden change in the gear ratio. Therefore, the upper limit guard value γ (0) is output to the second solenoid valve 4000 as a shift command value (S102).

  By controlling the second solenoid valve 4000, as shown in FIG. 5D, the hydraulic pressure of the input side pulley 232 decreases. Then, the hydraulic pressure of the input side pulley 232 increases as the actual input rotational speed increases. At this time, when the engine speed is equal to or higher than a predetermined speed α (YES at S106), the hydraulic pressure of the input pulley 232 is equal to or higher than a predetermined hydraulic pressure β (YES at S108), and the gear ratio is suddenly changed. If any one of the conditions for the elapse of a predetermined time from the detection of being performed (YES in S104) is satisfied, the execution of the upper limit guard is terminated. As shown in FIG. 5 (C), at time T (1), for example, as shown in FIG. 5 (B), the engine rotational speed becomes equal to or higher than a predetermined rotational speed α, or FIG. As shown in FIG. 5, when the oil pressure in the input pulley 232 becomes equal to or higher than a predetermined oil pressure β, or when a predetermined time elapses as shown in FIG. (S110). That is, the shift duty value γ (1) calculated according to the difference between the actual input rotation speed and the target input rotation speed is output to the second solenoid valve 4000 as a shift command value.

  As described above, according to the continuously variable transmission control apparatus according to the present embodiment, when the hydraulic pump is driven by the engine, the hydraulic pressure of the hydraulic pump increases as the engine speed increases. Therefore, when the engine speed is equal to or higher than a predetermined speed α at which a hydraulic pressure at which no belt slip occurs in the hydraulic pump can be secured, or the hydraulic pressure of the input pulley (or the control value of the second solenoid valve). If a predetermined time elapses after it is detected that a sudden change in the transmission gear ratio is detected, the transmission gear ratio changes to the transmission gear ratio. By canceling the restriction, the shift time can be shortened as compared with the case where the restriction is maintained until the completion of the shift control while suppressing the occurrence of the belt slip. Therefore, deterioration of drivability can be suppressed. Therefore, it is possible to provide a control device for a continuously variable transmission that suppresses the deterioration of drivability while suppressing the occurrence of belt slip when a sudden change in the gear ratio is executed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a control block diagram of the automatic transmission according to the embodiment of the present invention. FIG. 2 is a detailed view of the CVT shown in FIG. 1. It is a figure which shows a part of hydraulic circuit for the transmission control of CVT. It is a flowchart which shows the control structure of the program performed with ECT_ECU which is a control apparatus of the continuously variable transmission which concerns on embodiment of this invention. It is a timing chart which shows operation | movement of ECT_ECU which is a control apparatus of the continuously variable transmission which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Engine, 200 Speed change mechanism, 210 Fluid transmission mechanism, 212 Lock-up clutch, 214 Damper, 220 Forward / reverse switching mechanism, 232 Primary pulley, 234 Secondary pulley, 236 Belt, 290 Input shaft, 300 Output shaft, 400 Differential gear, 500 Drive wheel, 600 revolution speed sensor, 700 acceleration / deceleration operation device, 800 engine ECU, 900 ECT_ECU, 1000 shift device, 3100 first flow control valve, 3200 second flow control valve, 3900, 4000 solenoid valve, 4800 pressure regulating valve.

Claims (8)

A belt-type continuously variable transmission that is mounted on a vehicle and that changes the groove width of the pulley by hydraulic pressure generated by a hydraulic power source, thereby changing the effective engagement diameter of the endless belt wound around the pulley and controlling the transmission ratio. When the gear ratio is increased, the effective engagement diameter of the input pulley decreases, and the control device
Detecting means for detecting whether or not a sudden change in the gear ratio is executed;
When it is detected that the sudden change is executed, a gear ratio limiting means for limiting a change in the gear ratio;
A state detection means for detecting the state of any of the hydraulic pressure of the hydraulic source and the hydraulic pressure of the input pulley;
A control device for a continuously variable transmission, including release means for releasing the restriction based on either the hydraulic pressure of the hydraulic source or the hydraulic pressure of the input pulley. The control device further includes means for detecting a gear ratio of the continuously variable transmission,
The control of the continuously variable transmission according to claim 1, wherein the detecting means includes means for detecting that the sudden change is executed when the speed of change of the speed ratio is equal to or higher than a predetermined speed. apparatus. The controller is
Means for calculating a target input rotational speed of the continuously variable transmission based on a running state of the vehicle;
Means for controlling the continuously variable transmission such that the target input rotational speed matches the actual input rotational speed of the continuously variable transmission;
The detection means includes means for detecting that the sudden change is executed when a difference between the target input rotation speed and the actual input rotation speed of the continuously variable transmission is equal to or greater than a predetermined value. The control device for the continuously variable transmission according to claim 1. The state detection means includes a rotation speed detection means for detecting the rotation speed of a power source that varies the hydraulic pressure of the hydraulic power source,
The continuously variable transmission according to any one of claims 1 to 3, wherein the releasing means includes means for releasing the restriction when the detected rotational speed is equal to or higher than a predetermined rotational speed. Control device. The state detection means includes a hydraulic pressure detection means for detecting the hydraulic pressure of the input pulley,
The control device for a continuously variable transmission according to any one of claims 1 to 3, wherein the releasing means includes means for releasing the restriction when the detected oil pressure is equal to or higher than a predetermined oil pressure. . The continuously variable transmission is provided with a solenoid valve for controlling the hydraulic pressure of the input side pulley,
The state detection means includes means for detecting a control value of the electromagnetic valve,
The said cancellation | release means contains a means for canceling | releasing the said limitation, when the detected control value is a control value corresponding to the hydraulic pressure more than the predetermined hydraulic pressure in the said input side pulley. A control device for a continuously variable transmission according to any one of the above.   7. The device according to claim 1, wherein the canceling unit includes a unit for canceling the restriction when a predetermined time elapses after it is detected that the sudden change is executed. Control device for step transmission. The continuously variable transmission is provided with a solenoid valve for controlling the hydraulic pressure of the input side pulley,
The continuously variable transmission control device according to any one of claims 1 to 7, wherein the speed ratio limiting means includes means for limiting a control value during downshifting of the solenoid valve.

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