JP5817583B2 - Control device for continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission, and more particularly to a technique for correcting hydraulic pressure supplied to a movable pulley in accordance with the moving speed of the movable pulley.

  A continuously variable transmission is known in which an annular belt or chain is wound between a primary pulley (also referred to as a primary sheave) having a V-shaped groove and a secondary pulley (also referred to as a secondary sheave). In this type of continuously variable transmission, a groove ratio is changed by moving a movable pulley (also referred to as a movable sheave) to achieve a desired gear ratio. The movable pulley moves when hydraulic pressure is supplied or discharged.

  When the hydraulic pressure is supplied, a predetermined amount of hydraulic oil flows through the oil passage as the movable pulley moves. Since the hydraulic oil is a fluid, various phenomena such as a pressure drop can occur due to the flow of the hydraulic oil. Such a phenomenon may cause a difference between the target hydraulic pressure and the actual hydraulic pressure.

  Japanese Patent No. 3607640 (Patent Document 1) discloses an example of a technique for coping with an adverse effect caused by the flow of hydraulic oil. A hydraulic control device configured to counteract the influence is disclosed.

Japanese Patent No. 3607640

  However, if the hydraulic pressure supplied to the movable pulley is always corrected according to the flow of hydraulic oil, for example, an overshoot or undershoot resulting from the feedback control of the transmission ratio occurs, and the transmission ratio increases or decreases after the end of the transmission. In this case, the hydraulic pressure is corrected. In such a case, the correction amount of the hydraulic pressure becomes excessive, and as a result, the control may become unstable.

  The present invention has been made to solve the above-described problems, and an object thereof is to prevent the instability of hydraulic pressure due to correction according to the flow of hydraulic oil.

  In one embodiment, a control device for a continuously variable transmission in which a transmission gear ratio is determined according to the position of a movable pulley that is supplied with hydraulic pressure moves so that a target change width of the position of the movable pulley is greater than a predetermined first threshold value. Is supplied to the movable pulley when at least one of the first condition that the moving pulley is larger than the second condition that the moving speed of the movable pulley is larger than a predetermined second threshold is satisfied. The hydraulic pressure is corrected according to the moving speed of the movable pulley, and if neither the first condition nor the second condition is satisfied, the correction of the hydraulic pressure according to the moving speed of the movable pulley is limited.

  According to this configuration, the hydraulic pressure supplied to the movable pulley is reduced when the gear ratio is expected to change rapidly, such as when the target change width of the position of the movable pulley is large or when the moving speed of the movable pulley is large. While the correction is made according to the moving speed of the movable pulley, that is, the flow rate of the hydraulic oil, the correction of the hydraulic pressure according to the moving speed of the movable pulley is limited when it is not necessary to change the gear ratio quickly. Thereby, when there is no need to change the gear ratio immediately, it is possible to avoid an excessive correction amount of the hydraulic pressure. Therefore, it is possible to prevent hydraulic pressure from becoming unstable due to correction according to the moving speed of the movable pulley, that is, correction according to the flow of hydraulic oil.

  In another embodiment, the control device ends the correction of the hydraulic pressure after starting the correction of the hydraulic pressure according to the moving speed of the movable pulley and before the movable pulley reaches the target position.

  According to this configuration, the correction of the hydraulic pressure according to the moving speed of the movable pulley is completed before the shift is completed. Thereby, it is possible to avoid erroneous correction due to the operation delay of the movable pulley at the end of the shift. Therefore, it is possible to prevent hydraulic pressure from becoming unstable.

  In yet another embodiment, the control device corrects the hydraulic pressure supplied to the movable pulley as the moving speed of the movable pulley increases.

  According to this configuration, since the moving speed of the movable pulley is high, the flow rate of the hydraulic oil is high. As a result, when the hydraulic pressure drop amount is large, the hydraulic pressure drop can be compensated.

  In yet another embodiment, the control device corrects the hydraulic pressure supplied to the movable pulley according to the moving speed of the movable pulley when both the first condition and the second condition are satisfied, When at least one of the condition and the second condition is not satisfied, the correction of the hydraulic pressure according to the moving speed of the movable pulley is limited.

  According to this configuration, the hydraulic pressure supplied to the movable pulley becomes the moving speed of the movable pulley, that is, the flow rate of the hydraulic oil only when the target change width of the position of the movable pulley is large and the moving speed of the movable pulley is high. It is corrected accordingly. On the other hand, if the target change range of the position of the movable pulley is small or the moving speed of the movable pulley is small, there is no need to change the gear ratio immediately, so the correction of hydraulic pressure according to the moving speed of the movable pulley is limited. Is done. Thereby, when there is no need to change the gear ratio immediately, it is possible to avoid an excessive correction amount of the hydraulic pressure.

  In yet another embodiment, the continuously variable transmission is mounted on a vehicle. The control device sets the target position of the movable pulley according to the vehicle speed, and calculates a dynamic target position that changes with a delay with respect to the change of the target position. The target change width is a difference between the target position and the dynamic target position. The moving speed of the movable pulley under the second condition is a dynamic target position changing speed.

  According to this configuration, it is possible to determine whether or not to correct the hydraulic pressure without using the actual moving speed of the movable pulley. Therefore, the hydraulic pressure can be corrected in advance in consideration of operation delays and dead time of the devices.

It is a figure which shows the power train of a vehicle. It is a block diagram of a control system mainly composed of an ECU. FIG. 2 is a first diagram illustrating a hydraulic control circuit. FIG. 3 is a second diagram illustrating a hydraulic control circuit. It is a figure which shows the relationship between the target rotational speed of the input shaft of a continuously variable transmission, and the vehicle speed. It is a figure which shows the flow of override correction. It is a figure which shows the relationship between the moving speed of a movable pulley, and override correction pressure. It is a figure which shows the driving | running state in which override correction | amendment is performed. It is a flowchart which shows the process which ECU performs.

  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.

  A vehicle equipped with a control device according to the present embodiment will be described with reference to FIG. The output of the engine 200 of the power train 100 mounted on this vehicle is input to a belt-type or chain-type continuously variable transmission (CVT) 500 via a torque converter 300 and a forward / reverse switching device 400. The The output of the continuously variable transmission 500 is transmitted to the reduction gear 600 and the differential gear device 700, and is distributed to the left and right drive wheels 800. The power train 100 is controlled by an ECU (Electronic Control Unit) 900 described later. The ECU 900 corresponds to the control device in the claims.

  The torque converter 300 includes a pump impeller 302 connected to the crankshaft of the engine 200 and a turbine impeller 306 connected to the forward / reverse switching device 400 via the turbine shaft 304. A lockup clutch 308 is provided between the pump impeller 302 and the turbine impeller 306. The lockup clutch 308 is engaged or released when the hydraulic pressure supply to the engagement side oil chamber and the release side oil chamber is switched.

  When the lockup clutch 308 is completely engaged, the pump impeller 302 and the turbine impeller 306 are integrally rotated. The pump impeller 302 is provided with a mechanical oil pump 310 that generates hydraulic pressure for controlling the transmission of the continuously variable transmission 500, generating a belt clamping pressure, and supplying lubricating oil to each part. ing.

  The forward / reverse switching device 400 is composed of a double pinion type planetary gear device. Turbine shaft 304 of torque converter 300 is connected to sun gear 402. The input shaft 502 of the continuously variable transmission 500 is connected to the carrier 404. Carrier 404 and sun gear 402 are connected via forward clutch 406. Ring gear 408 is fixed to the housing via reverse brake 410. The forward clutch 406 and the reverse brake 410 are frictionally engaged by a hydraulic cylinder. The input rotational speed of the forward clutch 406 is the same as the rotational speed of the turbine shaft 304, that is, the turbine rotational speed NT.

  When the forward clutch 406 is engaged and the reverse brake 410 is released, the forward / reverse switching device 400 enters the forward engagement state. In this state, the driving force in the forward direction is transmitted to the continuously variable transmission 500. When the reverse brake 410 is engaged and the forward clutch 406 is released, the forward / reverse switching device 400 enters the reverse engagement state. In this state, the input shaft 502 is rotated in the reverse direction with respect to the turbine shaft 304. As a result, the driving force in the reverse direction is transmitted to the continuously variable transmission 500. When both forward clutch 406 and reverse brake 410 are released, forward / reverse switching device 400 enters a neutral state in which power transmission is interrupted.

  The continuously variable transmission 500 includes a primary pulley 504 provided on the input shaft 502, a secondary pulley 508 provided on the output shaft 506, and a transmission belt 510 wound around these pulleys. Power is transmitted using frictional forces between the pulleys and the transmission belt 510.

  The primary pulley 504 includes a movable pulley 512 that can move in the axial direction of the input shaft 502, and a fixed pulley (also referred to as a fixed sheave) 514 that is fixed to the input shaft 502. Similarly, the secondary pulley 508 includes a movable pulley 522 that can move in the axial direction of the output shaft 506 and a fixed pulley 524 that is fixed to the output shaft 506.

  When the movable pulley 512 of the primary pulley 504 moves in the axial direction of the input shaft 502, the groove width of the primary pulley 504 changes, and when the movable pulley 522 of the secondary pulley 508 moves in the axial direction of the output shaft 506, the secondary pulley The groove width of 508 changes.

  The gear ratio GR (= primary pulley rotation speed NIN / secondary pulley rotation speed NOUT) is continuously changed by changing the groove widths of the primary pulley 504 and the secondary pulley 508.

  As is well known, the movable pulley 512 and the movable pulley 522 move in accordance with the hydraulic pressure supplied to their back surfaces.

  As shown in FIG. 2, the ECU 900 includes an engine speed sensor 902, a turbine speed sensor 904, a vehicle speed sensor 906, a throttle opening sensor 908, a cooling water temperature sensor 910, an oil temperature sensor 912, an accelerator opening sensor 914, a foot A brake switch 916, a position sensor 918, a primary pulley rotation speed sensor 922, and a secondary pulley rotation speed sensor 924 are connected.

  The engine speed sensor 902 detects the engine speed (engine speed) NE of the engine 200. The turbine rotation speed sensor 904 detects the rotation speed (turbine rotation speed) NT of the turbine shaft 304. The vehicle speed sensor 906 detects the vehicle speed V. The throttle opening sensor 908 detects the opening degree θ (TH) of the electronic throttle valve. Cooling water temperature sensor 910 detects cooling water temperature T (W) of engine 200. The oil temperature sensor 912 detects the oil temperature T (C) of the continuously variable transmission 500 or the like. The accelerator opening sensor 914 detects the accelerator pedal opening A (CC). The foot brake switch 916 detects whether or not the foot brake is operated. The position sensor 918 detects the position P (SH) of the shift lever 920 by determining whether the contact provided at the position corresponding to the shift position is ON or OFF. Primary pulley rotation speed sensor 922 detects the rotation speed NIN of primary pulley 504. Secondary pulley rotation speed sensor 924 detects rotation speed NOUT of secondary pulley 508. A signal representing the detection result of each sensor is transmitted to ECU 900. The turbine rotational speed NT coincides with the primary pulley rotational speed NIN during forward traveling with the forward clutch 406 engaged. The vehicle speed V becomes a value corresponding to the secondary pulley rotation speed NOUT. Therefore, when the vehicle is stopped and the forward clutch 406 is engaged, the turbine speed NT is zero.

ECU 900 includes a CPU (Central Processing Unit), a memory, an input / output interface, and the like. The CPU performs signal processing according to a program stored in the memory. Thereby, output control of the engine 200, shift control of the continuously variable transmission 500, belt clamping pressure control, engagement / release control of the forward clutch 406, engagement / release control of the reverse brake 410, and the like are executed.

  Output control of the engine 200 is performed by an electronic throttle valve 1000, a fuel injection device 1100, an ignition device 1200, and the like. The hydraulic control circuit 2000 performs the shift control of the continuously variable transmission 500, the belt clamping pressure control, the engagement / release control of the forward clutch 406, and the engagement / release control of the reverse brake 410.

  The main part of the hydraulic control circuit 2000 will be described with reference to FIGS. The hydraulic control circuit 2000 described below is an example, and the present invention is not limited to this.

  The hydraulic pressure generated by the oil pump 310 is supplied to a primary regulator valve 2100, an LPM (Line Pressure Modulator) 1 valve 2310, an LPM2 valve 2320, and an LPM3 valve 2330 through a line pressure oil path 2002.

  The primary regulator valve 2100 is selectively supplied with control pressure from one of the SLT linear solenoid valve 2200 and the SLS linear solenoid valve 2210. Of the control pressure (output hydraulic pressure) of the SLT linear solenoid valve 2200 and the control pressure (output hydraulic pressure) of the SLS linear solenoid valve 2210, the control pressure supplied to the primary regulator valve 2100 is selected by the control valve 2400. The control valve 2400 will be described later.

  The spool of the primary regulator valve 2100 slides up and down according to the supplied control pressure. As a result, the hydraulic pressure generated by the oil pump 310 is regulated (adjusted) by the primary regulator valve 2100. The hydraulic pressure adjusted by primary regulator valve 2100 is used as line pressure PL. In the present embodiment, the higher the control pressure supplied to primary regulator valve 2100, the higher the line pressure PL. Note that the higher the control pressure supplied to the primary regulator valve 2100, the lower the line pressure PL may be.

  The hydraulic pressure output from the LPM2 valve 2320 is supplied to the SLT linear solenoid valve 2200 and the SLS linear solenoid valve 2210. The hydraulic pressure output from the LPM2 valve 2320 is supplied to the SLP linear solenoid valve 2220 in addition to the SLT linear solenoid valve 2200 and the SLS linear solenoid valve 2210.

  The SLT linear solenoid valve 2200, the SLS linear solenoid valve 2210, and the SLP linear solenoid valve 2220 are electromagnetic valves that generate a control pressure according to a current value determined by a duty signal (duty value) transmitted from the ECU 900.

  The LPM1 valve 2310 outputs a hydraulic pressure adjusted with the line pressure PL as a source pressure. The hydraulic pressure output from the LPM1 valve 2310 is supplied to the movable pulley 522 of the secondary pulley 508. The movable pulley 522 of the secondary pulley 508 is supplied with hydraulic pressure that prevents the transmission belt 510 from slipping. That is, the belt clamping pressure is increased or decreased according to the output hydraulic pressure from the LPM1 valve 2310.

  The LPM1 valve 2310 is provided with a spool that is movable in the axial direction and a spring that biases the spool to one side. The LPM1 valve 2310 outputs the hydraulic pressure reduced by using the output hydraulic pressure of the SLS linear solenoid valve 2210 duty-controlled by the ECU 900 as a pilot pressure and the line pressure PL introduced into the LPM1 valve 2310 as the original pressure.

  The LPM2 valve 2320 outputs the hydraulic pressure reduced by using the line pressure PL as the original pressure. As described above, the hydraulic pressure output from the LPM2 valve 2320 is supplied to the SLT linear solenoid valve 2200, the SLS linear solenoid valve 2210, and the SLP linear solenoid valve 2220.

  The LPM3 valve 2330 outputs a hydraulic pressure that is regulated using the line pressure PL as a source pressure. The LPM3 valve 2330 is provided with a spool that is movable in the axial direction and a spring that biases the spool to one side. LPM3 valve 2330 reduces line pressure PL introduced to LPM3 valve 2330 using the output hydraulic pressure of SLP linear solenoid valve 2220 duty-controlled by ECU 900 as a pilot pressure. That is, the hydraulic pressure controlled by the SLP linear solenoid valve 2220 is output from the LPM3 valve 2330.

  The hydraulic pressure output from the LPM3 valve 2330 is supplied to the movable pulley 512 of the primary pulley 504 via the control valve 2400. The gear ratio GR of the continuously variable transmission 500 is controlled by controlling the supply and discharge of the hydraulic pressure from the primary pulley 504 to the movable pulley 512.

  When the hydraulic pressure supplied to the movable pulley 512 of the primary pulley 504 increases, the groove width of the primary pulley 504 becomes narrower. As a result, the gear ratio GR decreases. That is, continuously variable transmission 500 is upshifted.

  When the hydraulic pressure supplied to the movable pulley 512 of the primary pulley 504 decreases, the groove width of the primary pulley 504 increases. As a result, the gear ratio GR increases. That is, continuously variable transmission 500 is downshifted.

  The gear ratio GR is controlled such that, for example, the primary pulley rotation speed NIN becomes a target rotation speed set using a map. The target rotational speed is set using a map having the vehicle speed V and the accelerator opening ACC as parameters. The control method of the gear ratio GR is not limited to this.

  Modulator valve 2340 outputs the reduced hydraulic pressure using the hydraulic pressure output from LPM2 valve 2320 as a source pressure. The hydraulic pressure output from the modulator valve 2340 is supplied to the SL solenoid valve 2500.

  The control valve 2400 includes a first oil passage 2510 to which a hydraulic pressure obtained by reducing the line pressure using the LPM2 valve 2320 is supplied, a second oil passage 2520 to which a hydraulic pressure controlled by the SLT linear solenoid valve 2200 is supplied, and an SLP linear solenoid. An input port to which a third oil passage 2530 to which hydraulic pressure controlled by the valve 2220 is supplied and a fourth oil passage 2540 to supply hydraulic pressure to the secondary pulley 508 are connected to each other is provided. An orifice 2542 is provided on the fourth oil passage 2540.

  Note that an oil passage that does not supply hydraulic pressure to the primary pulley 504 and supplies hydraulic pressure to devices other than the secondary pulley 508 may be used as the fourth oil passage 2540.

  Further, the control valve 2400 is connected to a fifth oil passage 2550 for supplying hydraulic pressure to the forward clutch 406 or the reverse brake 410 and a sixth oil passage 2560 for supplying hydraulic pressure to the primary pulley 504 via a manual valve 2600 described later. Output port.

  In FIG. 3, the spool of the control valve 2400 is switched to either one of the state (A) (left side state) or the state (B) (right side state).

  That is, the control valve 2400 communicates the first oil passage 2510 and the fifth oil passage 2550, blocks the second oil passage 2520 and the fifth oil passage 2550, and also connects the third oil passage 2530 and the sixth oil passage. 2560, the fourth oil passage 2540 and the sixth oil passage 2560 are blocked, and the second oil passage 2520 and the fifth oil passage 2550 are in communication with each other. The state of (B) which interrupts | blocks the 5th oil path 2550, and connects the 4th oil path 2540 and the 6th oil path 2560, and interrupts | blocks the 3rd oil path 2530 and the 6th oil path 2560 is switched.

  When the spool of the control valve 2400 is in the state (A) in FIG. 3 (left side state), the control pressure is supplied from the SLT linear solenoid valve 2200 to the primary regulator valve 2100. That is, the line pressure PL is controlled according to the control pressure of the SLT linear solenoid valve 2200.

  When the spool of the control valve 2400 is in the state (B) in FIG. 3 (right state), the control pressure is supplied from the SLS linear solenoid valve 2210 to the primary regulator valve 2100. That is, the line pressure PL is controlled according to the control pressure of the SLS linear solenoid valve 2210.

  The spool of the control valve 2400 is urged in one direction by a spring. Hydraulic pressure is supplied from the SL solenoid valve 2500 so as to oppose the urging force of the spring.

  When hydraulic pressure is supplied from the SL solenoid valve 2500 to the control valve 2400, the spool of the control valve 2400 is in a state (B) in FIG.

  When the hydraulic pressure is not supplied from the SL solenoid valve 2500 to the control valve 2400, the spool of the control valve 2400 is in a state (A) in FIG. 3 due to the urging force of the spring.

  For example, when a garage shift is performed in which the shift lever 920 is operated from the “N” position to the “D” position or the “R” position, that is, the forward clutch 406 or the reverse brake 410 is changed from the released state to the engaged state. In this case, the SL solenoid valve 2500 is controlled so that the spool of the control valve 2400 is switched from the state (A) to the state (B) in FIG. That is, the SL solenoid valve 2500 is controlled by the ECU 900 so as to output the hydraulic pressure.

  When the continuously variable transmission 500 is downshifted in a state where the continuously variable transmission 500 is controlled not to downshift, the spool of the control valve 2400 is changed from the state (A) to the state (B) in FIG. SL solenoid valve 2500 is controlled to switch to That is, when an abnormal downshift is performed, the spool of control valve 2400 is switched from the state (A) to the state (B).

  Since ECU 900 determines how to control continuously variable transmission 500, it is determined in ECU 900 whether continuously variable transmission 500 is controlled so as not to downshift. Is done. Whether or not the downshift has occurred is determined based on whether or not the ratio between the primary pulley rotational speed NIN and the secondary pulley rotational speed NOUT has changed. Note that the method for determining whether or not the continuously variable transmission 500 is downshifted in a state where the continuously variable transmission 500 is controlled so as not to downshift is not limited thereto.

  In addition to the case where the garage shift is performed and the case where the abnormal downshift is performed, the condition that the vehicle stops with the shift lever 920 in the “D” position (the vehicle speed becomes “0”) is included. When the neutral control execution condition is satisfied, or when the shift lever 920 is operated to the “R” position while the vehicle is traveling forward, the spool of the control valve 2400 is changed from the state shown in FIG. Switch to state.

  The manual valve 2600 will be described with reference to FIG. Manual valve 2600 is mechanically switched according to the operation of shift lever 920. Thereby, the forward clutch 406 and the reverse brake 410 are engaged or released.

  Shift lever 920 is operated to a “P” position for parking, an “R” position for reverse travel, an “N” position for interrupting power transmission, a “D” position and “B” position for forward travel.

  In the “P” position and the “N” position, the hydraulic pressure in the forward clutch 406 and the reverse brake 410 is drained from the manual valve 2600. Thereby, the forward clutch 406 and the reverse brake 410 are released.

  In the “R” position, hydraulic pressure is supplied from the manual valve 2600 to the reverse brake 410. Thereby, the reverse brake 410 is engaged. On the other hand, the hydraulic pressure in forward clutch 406 is drained from manual valve 2600. As a result, the forward clutch 406 is released.

  In the “D” position and the “B” position, hydraulic pressure is supplied from the manual valve 2600 to the forward clutch 406. As a result, the forward clutch 406 is engaged. On the other hand, the hydraulic pressure in the reverse brake 410 is drained from the manual valve 2600. Thereby, the reverse brake 410 is released.

  When the shift lever 920 is in the “D” position, the target rotational speed can take a value within a region indicated by hatching in FIG. That is, the gear ratio can change between the highest gear ratio and the lowest gear ratio among the gear ratios set in continuously variable transmission 500.

  Since the input shaft rotation speed of continuously variable transmission 500 is determined according to the gear ratio of continuously variable transmission 500 and the gear ratio is determined according to the position of movable pulley 512, in this embodiment, continuously variable transmission. The input shaft rotational speed of 500, the gear ratio, and the position of the movable pulley 512 can be handled as having substantially the same meaning. Therefore, the present invention may be applied by replacing the input shaft 502 of the continuously variable transmission 500 with the gear ratio or the position of the movable pulley 512. As an example, instead of the target rotational speed of the input shaft 502 of the continuously variable transmission 500, a target gear ratio or a target position of the movable pulley 512 may be determined.

  Hereinafter, with reference to FIG. 6, correction of the target hydraulic pressure (hereinafter also referred to as override correction) based on the moving speed of the movable pulley 512 of the primary pulley 504 will be described. As an example, the override correction is executed by the ECU 900.

  The override correction is performed by adding an override correction pressure to the target hydraulic pressure of the movable pulley 512 in order to compensate and cancel out a pressure drop that may occur when the hydraulic oil supplied to the movable pulley 512 of the primary pulley 504 passes through an orifice or the like. It is a correction to be added. Note that the override correction pressure may be a negative value. As an example, when the moving speed of the movable pulley 512 of the primary pulley 504 is a negative value, the override correction pressure may be a negative value. In this case, the target hydraulic pressure is reduced as a result.

  In this embodiment, as an example, the speed at which the movable pulley 512 moves in the direction in which the groove width of the primary pulley 504 becomes narrower is a positive value, and the groove in the primary pulley 504 becomes movable in the direction in which the groove width becomes wider. Although the speed at which the pulley 512 moves is set to a negative value, the speed is not limited to this and may be reversed.

  In obtaining the moving speed of the movable pulley 512 of the primary pulley 504, the position of the movable pulley 512 is obtained from the gear ratio of the continuously variable transmission 500, as indicated by a block B1. As described above, since the gear ratio of the continuously variable transmission 500 is determined according to the position of the movable pulley 512, for example, a map showing the relationship between the gear ratio of the continuously variable transmission 500 and the position of the movable pulley 512 is shown. By creating in advance, the position of the movable pulley 512 is obtained from the gear ratio of the continuously variable transmission 500.

  Thereafter, as indicated by block B2, the moving speed of the movable pulley 512 is calculated from the obtained position of the movable pulley 512. As an example, the moving speed of the movable pulley 512 is calculated by differentiating the obtained position of the movable pulley 512, but the method of calculating the moving speed is not limited to this.

  Thereafter, as indicated by block B3, an override correction pressure for the target hydraulic pressure is calculated in accordance with the calculated moving speed. As an example, the override correction pressure is calculated from a two-dimensional map of the moving speed and the override correction pressure created in advance by the developer. As an example, as shown in FIG. 7, the override correction pressure is calculated so as to increase as the moving speed of the movable pulley 512 increases. However, the present invention is not limited to this.

  Returning to FIG. 6, the calculated override correction pressure is added to the target hydraulic pressure, thereby correcting the target hydraulic pressure and determining the command hydraulic pressure. Therefore, the hydraulic pressure supplied to the movable pulley 512 is corrected so that the higher the moving speed of the movable pulley 512, the larger the moving speed. Thereby, since the moving speed of the movable pulley 512 is high, the flow rate of the hydraulic oil is high, and as a result, when the hydraulic pressure drop is large, the hydraulic pressure drop can be compensated.

  With reference to FIG. 8, the operation state in which the override correction pressure is added to the target hydraulic pressure will be described.

  In the present embodiment, as an example, the override correction pressure is added to the target hydraulic pressure only in an operating state in which the gear ratio of continuously variable transmission 500 changes significantly and rapidly. Specifically, the first condition that the target change width of the position of the movable pulley 512 is larger than a predetermined first threshold is satisfied, and the moving speed of the movable pulley 512 (more specifically, the target moving speed). ) Is larger than a predetermined second threshold value, the override correction is executed, and the override correction pressure is added to the target hydraulic pressure.

  When at least one of the first condition and the second condition is not satisfied, the override correction is limited. As an example, the override correction is not executed and the target hydraulic pressure is used as it is as the command hydraulic pressure.

  By executing the override correction only when the target change width of the position of the movable pulley 512 is large and the moving speed of the movable pulley 512 is large, that is, when the gear ratio is expected to change rapidly. When there is no need to change the gear ratio immediately, it is possible to avoid the hydraulic pressure supplied to the movable pulley 512 from becoming excessive due to the override correction. Therefore, instability of hydraulic pressure due to override correction can be prevented.

  The override correction may be limited by reducing the absolute value of the override correction pressure. The override correction pressure is added to the target hydraulic pressure when at least one of the first condition and the second condition is satisfied, and the override is applied when neither the first condition nor the second condition is satisfied. The correction may be limited.

  In the present embodiment, the target change width of the position of the movable pulley 512 is obtained as a difference between the target position shown in FIG. 8 and the dynamic target position. The target position is determined from the target rotational speed of the input shaft 502 of the continuously variable transmission 500 described with reference to FIG. When the target rotational speed is determined, the target gear ratio is determined from the determined target rotational speed and the actual rotational speed of the output shaft 506. As described above, since the gear ratio of the continuously variable transmission 500 is determined according to the position of the movable pulley 512, the position of the movable pulley 512 that achieves the target gear ratio is determined as the target position. Note that the target change width may be calculated using the target gear ratio or the target rotation speed instead of the target position. That is, instead of the position of the movable pulley 512, the present invention may be implemented using the rotation speed or the gear ratio of the input shaft 502 of the continuously variable transmission 500.

  The dynamic target position is calculated by ECU 900 so as to change with a delay with respect to the change of the target position. As an example, the position of the primary delay or the secondary delay with respect to the changed target position is calculated as the dynamic target position.

  The moving speed of the movable pulley 512 in the second condition is a dynamic target position changing speed. The change speed of the dynamic target position is different from the actual moving speed of the movable pulley 512, and can be said to be the target value of the moving speed of the movable pulley 512, that is, the target moving speed. As an example, the target moving speed of the movable pulley 512 is calculated by differentiating the calculated dynamic target position.

  By using the dynamic target position calculated from the target position, it is possible to determine whether or not to perform override correction without detecting the actual position and moving speed of the movable pulley 512. Therefore, the override correction can be performed in advance in consideration of the operation delay and the dead time of the devices.

  Instead of the dynamic target position, the actual position of the movable pulley 512 calculated from the gear ratio or the like, or the position obtained using a model (function) for predicting the position of the movable pulley 512 is used. May be used. In addition, the actual moving speed of the movable pulley 512 may be used instead of the target moving speed, or the moving speed may be calculated from a position obtained using a model (function) for predicting the position of the movable pulley 512. .

  As shown in FIG. 8, after the start of the override correction, the override correction is ended before the shift is completed, that is, before the movable pulley 512 reaches the target position. As an example, the time required for the movable pulley 512 to reach the target position is predicted from the change rate (decrease rate) of the difference between the target position and the actual position, and a predetermined time greater than zero is predicted time. If it falls below, the override correction is terminated.

  By terminating the override correction before the shift is completed, it is possible to avoid erroneous correction due to the operation delay of the movable pulley 512 at the end of the shift. Therefore, it is possible to prevent hydraulic pressure from becoming unstable.

  After completion of the override correction, the override correction pressure is decreased at a predetermined decrease rate, and finally becomes zero. The decrease rate may be decreased or increased as the added override correction pressure is increased.

  With reference to FIG. 9, the process which ECU900 performs is demonstrated. The processing described below may be realized by software, may be realized by hardware, or may be realized by cooperation of software and hardware.

  In step (hereinafter step is abbreviated as S) 100, the first condition that the target change width of the position of the movable pulley 512 is larger than a predetermined first threshold is satisfied, and the moving speed of the movable pulley 512 is satisfied. It is determined whether or not a second condition that is greater than a predetermined second threshold is satisfied.

  When both the first condition and the second condition are satisfied (YES in S100), override correction is executed in S102, and the override correction pressure is added to the target hydraulic pressure.

  After the override correction is performed, the time until the shift is completed, that is, the time until the movable pulley 512 reaches the target position, the time until the speed ratio reaches the target speed ratio, or the rotation speed of the input shaft 502 is the target. If the time required to reach the rotational speed falls below a predetermined time (YES in S104), the override correction is terminated in S106.

  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.

  100 power train, 200 engine, 300 torque converter, 310 oil pump, 312 converter cover, 400 forward / reverse switching device, 402 sun gear, 404 carrier, 406 forward clutch, 408 ring gear, 410 reverse brake, 500 continuously variable transmission, 502 input Shaft, 504 Primary pulley, 506 Output shaft, 508 Secondary pulley, 510 Transmission belt, 600 Reduction gear, 700 Differential gear device, 800 Drive wheel, 900 ECU, 902 Engine speed sensor, 904 Turbine speed sensor, 906 Vehicle speed sensor 908, throttle opening sensor, 910 cooling water temperature sensor, 912 oil temperature sensor, 914 accelerator opening sensor, 916 foot brake switch, 918 position sensor, 20 Shift lever, 922 Primary pulley rotation speed sensor, 924 Secondary pulley rotation speed sensor, 930 Stall determination unit, 932 Fail safe control unit, 934 Vehicle speed detection unit, 936 Fail safe end unit, 938 Engagement prohibition unit, 940 Abnormality determination unit , 1000 Electronic throttle valve, 1100 Fuel injection device, 1200 Ignition device, 2000 Hydraulic control circuit, 2002 Line pressure oil passage, 2100 Primary regulator valve, 2200 SLT linear solenoid valve, 2210 SLS linear solenoid valve, 2220 SLP linear solenoid valve, 2310 LPM1 valve, 2320 LPM2 valve, 2330 LPM3 valve, 2340 Modulator valve, 2400 Control valve, 2500 SL solenoid Idobarubu, 2510 the first oil passage, 2520 the second oil passage, 2530 third oil passage, 2540 No. 4 oil passage, 2542 orifices, 2550 No. 5 oil passage, 2560 No. 6 oil passage, 2600 manual valve.

Claims (4)

A control device for a continuously variable transmission in which a gear ratio is determined according to a position of a movable pulley that is supplied with hydraulic pressure and moves.
A first condition that the target change width of the position of the movable pulley is larger than a predetermined first threshold value, and a second condition that the moving speed of the movable pulley is larger than a predetermined second threshold value. When both of the conditions are satisfied, the hydraulic pressure supplied to the movable pulley is corrected according to the moving speed of the movable pulley,
A control device for a continuously variable transmission that restricts correction of hydraulic pressure in accordance with a moving speed of the movable pulley when at least one of the first condition and the second condition is not satisfied.   2. The continuously variable transmission according to claim 1, wherein the control device ends the correction of the hydraulic pressure after starting the correction of the hydraulic pressure according to the moving speed of the movable pulley and before the movable pulley reaches a target position. Machine control device.   The control device for a continuously variable transmission according to claim 1, wherein the control device corrects the hydraulic pressure supplied to the movable pulley as the moving speed of the movable pulley increases. The continuously variable transmission is mounted on a vehicle,
The controller is
Set the target position of the movable pulley according to the vehicle speed,
Calculating a dynamic target position that changes with a delay relative to the change in the target position;
The target change width is a difference between the target position and the dynamic target position,
2. The continuously variable transmission control device according to claim 1, wherein the moving speed of the movable pulley under the second condition is a speed of change of the dynamic target position.

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