JP2005098329A - Apparatus for controlling speed changing of non-stage transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for controlling speed changing of a non-stage transmission, which apparatus can suppress the decline of the followability and convergency when the actual speed changing ratio of the non-stage transmission is brought near to the target speed changing ratio. <P>SOLUTION: The apparatus for controlling speed changing of the non-stage transmission carries out the feedback control for bringing the actual speed changing ratio near to the target speed changing ratio. The apparatus comprises a deviation judging means for judging the degree of variation of the deviation between the target speed changing ratio and the actual speed changing ratio (steps S2, S3), and a control changing means for selectively changing the feedback control including the proportional control action and the feedback control including the proportional control action and the integral control action (steps from S4 to S14). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transmission control device for a continuously variable transmission that controls a transmission ratio of a continuously variable transmission mounted on a vehicle.

  Conventionally, a vehicle in which a continuously variable transmission is mounted on a power transmission path from an engine to wheels is known. When controlling the gear ratio between the input member and the output member of the continuously variable transmission, feedback control of the gear ratio of the continuously variable transmission is performed with the target engine speed at which the fuel consumption state in the engine is optimized. It is possible. If such a continuously variable transmission is performed, the fuel efficiency is improved and the gear ratio is continuously switched, so that there is little shock associated with the gear shifting. However, since the shift control of the continuously variable transmission is automatically performed based on the shift map, the driver cannot freely select the gear ratio. For example, when climbing or accelerating, it is not possible to execute control such as selecting a gear ratio that prioritizes driving force over fuel consumption or selecting a gear ratio that increases engine braking force when descending a slope. Therefore, a continuously variable transmission having a manual transmission mode in which a driver can arbitrarily change the gear ratio of the continuously variable transmission is known.

  In this manual transmission mode, it is necessary to execute a control different from the feedback control executed in the automatic transmission mode in order to obtain the speed ratio intended by the driver as quickly as possible. For example, there is a method of performing feedback control only by proportional operation, and an example thereof is described in Patent Document 1. The vehicle described in Patent Document 1 is configured such that engine power is transmitted to drive wheels via a continuously variable transmission. The continuously variable transmission is a mechanism that can continuously change 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. A step transmission is mentioned.

  The belt type continuously variable transmission includes a driving pulley attached to an input shaft, a driven pulley attached to an output shaft, and a belt wound around the driving pulley and the driven pulley. It is a transmission. The driving pulley has a fixed sheave and a movable sheave, and is provided with a hydraulic actuator that presses the movable sheave in a direction approaching the fixed sheave. The hydraulic actuator is supplied and discharged with hydraulic pressure so as to obtain a gear ratio for matching the rotational speed of the input shaft to the target input rotational speed.

For example, when the automatic transmission mode is selected, the target input rotation speed is calculated and the target input rotation speed is calculated based on the accelerator opening, the vehicle speed, etc., so that the engine rotation speed becomes the minimum fuel consumption. On the other hand, the gear ratio of the belt-type continuously variable transmission is controlled so that the actual input rotational speed matches. On the other hand, when the manual transmission mode is selected, the gear ratio of the belt type continuously variable transmission can be controlled by manually operating the shift device. As the shift device, a switch provided corresponding to each of the first speed to the sixth speed, a switch for upshifting the current gear ratio, a switch for downshifting, and the like are described. By the way, the actual control of the gear ratio of the belt type continuously variable transmission is executed by controlling the duty ratio of the signal to the solenoid valve connected to the hydraulic actuator. In particular, in the manual transmission mode, when feedback control is performed on the transmission ratio of the belt type continuously variable transmission, only a proportional gain is used as a coefficient (gain) for controlling the duty ratio.
JP 2001-330122 A

  By the way, when only proportional control is used for a control object (belt type continuously variable transmission) having self-balance, as in the transmission control device for a continuously variable transmission described in Patent Document 1 above, target input rotation When the number or disturbance changes stepwise, a steady deviation remains. As a result, the followability and convergence of the actual input rotation speed with respect to the target input rotation speed may be reduced.

  The present invention has been made against the background of the above circumstances, and the transmission of the continuously variable transmission that can suppress the decrease in the followability and convergence when the actual transmission ratio of the continuously variable transmission is brought close to the target transmission ratio. The object is to provide a control device.

  In order to achieve the above object, the invention according to claim 1 is a transmission control device for a continuously variable transmission that executes feedback control for bringing an actual gear ratio closer to a target gear ratio, wherein the target gear ratio, the actual gear ratio, Deviation determining means for determining the degree of change of the deviation, and control switching means for selectively switching between feedback control including proportional action and feedback control including proportional action and integral action based on the determination result of the deviation determining means It is characterized by having.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, when the variation degree of the deviation is out of a predetermined range, feedback control including proportional action is selected, and the variation degree of the deviation is within the predetermined range. In some cases, the control switching means has a function of selecting feedback control including proportional action and integral action.

  In each claim, the “degree of deviation change” includes a deviation change amount, a deviation change rate, a deviation change rate, and the like. Further, the “speed ratio” includes, in addition to the speed ratio itself, an input rotation speed that is a parameter equivalent to the speed ratio.

  According to the first aspect of the present invention, the feedback control including the proportional operation and the feedback control including the proportional operation and the integral operation can be properly used according to the change in the target gear ratio and the disturbance, and the control system is stable. To do. Therefore, the followability and convergence of the actual speed ratio with respect to the target speed ratio are improved.

  According to the invention of claim 2, in addition to the same effect as the invention according to claim 1, when the deviation is outside the predetermined range, the feedback control including the proportional action is selected, and the integral term of the deviation is Since it is not included in the control law of the gear ratio, the control system becomes more stable. Therefore, the followability and convergence of the actual speed ratio with respect to the target speed ratio are further improved.

  Next, an embodiment of the present invention will be described with reference to the drawings. First, FIG. 2 shows a power train of a vehicle to which the present invention can be applied and a control system of the vehicle. In the vehicle Ve shown in FIG. 2, a fluid transmission device 3, a lockup clutch 4, a forward / reverse switching mechanism 5, a belt-type continuously variable transmission 6, and the like are provided on a power transmission path between the engine 1 and the wheels 2. ing. As the engine 1, an internal combustion engine, specifically, a gasoline engine, a diesel engine, an LPG engine, or the like can be used.

  The fluid transmission device 3 and the lockup clutch 4 are provided in a power transmission path between the engine 1 and the forward / reverse switching mechanism 5, and the fluid transmission device 3 and the lockup clutch 4 are arranged in parallel to each other. Has been. The fluid transmission device 3 is a device that transmits power by the kinetic energy of the fluid, and the lockup clutch 4 is a device that transmits power by a frictional force. The forward / reverse switching mechanism 5 is a device that selectively switches the rotation direction of the output member relative to the input member.

  The belt type continuously variable transmission 6 is provided in a power transmission path between the forward / reverse switching mechanism 5 and the wheels 2. The belt type continuously variable transmission 6 has a primary shaft 7 and a secondary shaft 8 arranged in parallel to each other. The primary shaft 7 is provided with a primary pulley 9, and the secondary shaft 8 is provided with a secondary pulley 10. The primary pulley 9 has a fixed sheave 11 fixed to the primary shaft 7 and a movable sheave 12 configured to be movable in the axial direction of the primary shaft 7. A groove M <b> 1 is formed between the fixed sheave 11 and the movable sheave 12.

  Further, a hydraulic servo mechanism 13 is provided for moving the movable sheave 12 in the axial direction of the primary shaft 7 so that the movable sheave 12 and the fixed sheave 11 approach and separate from each other. The hydraulic servo mechanism 13 includes a hydraulic chamber 19 and a piston (not shown) that operates in the axial direction of the primary shaft 7 according to the hydraulic pressure of the hydraulic chamber 19 and is connected to the movable sheave 12. .

  On the other hand, the secondary pulley 10 has a fixed sheave 14 fixed to the secondary shaft 8 and a movable sheave 15 configured to be movable in the axial direction of the secondary shaft 8. A V-shaped groove M <b> 2 is formed between the fixed sheave 14 and the movable sheave 15.

  In addition, a hydraulic servo mechanism 16 is provided that moves the movable sheave 15 in the axial direction of the secondary shaft 8 to bring the movable sheave 15 and the fixed sheave 14 closer to or away from each other. The hydraulic servo mechanism 16 includes a hydraulic chamber 100 and a piston (not shown) that operates in the axial direction of the secondary shaft 8 by the hydraulic pressure of the hydraulic chamber 100 and is connected to the movable sheave 15. An endless belt 17 is wound around the primary pulley 9 and the secondary pulley 10 configured as described above.

  On the other hand, a hydraulic control device 18 having a function of controlling the hydraulic servo mechanisms 13 and 16 and the lockup clutch 4 and the forward / reverse switching mechanism 5 of the belt type continuously variable transmission 6 is provided. Further, an electronic control device 52 as a controller for controlling the engine 1, the lockup clutch 4, the forward / reverse switching mechanism 5, the belt type continuously variable transmission 6, and the hydraulic control device 18 is provided. An arithmetic processing unit (CPU or MPU), a storage unit (RAM and ROM), and a microcomputer mainly including an input / output interface are included.

  The electronic control device 52 includes an operation state of the shift position selection device 50, an operation state of the transmission mode selection device 51, an operation state of the transmission ratio selection device 53, an engine speed, an acceleration request (for example, an operation state of an accelerator pedal), Detection signals such as a braking request (for example, an operation state of a brake pedal), an opening degree of a throttle valve, a rotation speed of the primary shaft 7, and a rotation speed of the secondary shaft 8 are input. A parking position, a reverse position, a neutral position, a first drive position, a second drive position, and the like can be selectively switched by operating a shift position selection device 50 by a vehicle occupant.

  Further, an automatic shift mode and a manual shift mode can be switched by operating a shift mode selection device 51 by a vehicle occupant. The automatic transmission mode is a belt type continuously variable on the basis of a signal input to the electronic control unit 52, for example, a signal such as a vehicle speed or an acceleration request, and data (shift map) stored in the electronic control unit 52. In this mode, the transmission ratio of the transmission 6 is controlled. The manual transmission mode is a mode in which the transmission ratio of the belt type continuously variable transmission 6 can be changed based on the operation state of the transmission ratio selection device 53. In this embodiment, the gear ratio selection device 53 has a downshift button 53A and an upshift button 53B.

  On the other hand, from the electronic control unit 52, a signal for controlling the engine 1, a signal for controlling the belt-type continuously variable transmission 6, a signal for controlling the forward / reverse switching mechanism 5, a signal for controlling the lock-up clutch 4, a hydraulic control unit A signal for controlling 18 is output. The hydraulic control device 18 includes a hydraulic circuit (not shown), a linear solenoid valve (not shown), and the like. The oil amount in the hydraulic chamber 19 and the hydraulic chamber 100 are set according to the energization current of the linear solenoid valve. Hydraulic pressure is controlled.

  Next, the power transmission action in the vehicle Ve shown in FIG. 1 will be described. When the first drive position, the second drive position, or the reverse position is selected, the power of the engine 1 is transmitted through the fluid transmission device 3 or the lockup clutch 4 and the forward / reverse switching mechanism 5 to the belt type. It is transmitted to the primary shaft 7 of the continuously variable transmission 6. The torque of the primary shaft 7 is transmitted to the secondary shaft 8 via the primary pulley 9, the belt 17, and the secondary pulley 10. Then, the torque of the secondary shaft 8 is transmitted to the wheel 2 to generate a driving force. When the neutral position or the parking position is selected, the engine torque is not transmitted to the wheels 2.

  The function of the control system of the vehicle Ve shown in FIG. 1 will be described. Various types of data are stored in the electronic control unit 52, and the engine 1, the belt-type continuously variable transmission 6, the forward / reverse switching mechanism based on the signal input to the electronic control unit 52 and the stored data. 5, the lock-up clutch 4, the hydraulic control device 18 and the like are controlled. First, the shift control of the belt type continuously variable transmission 6 will be described. First, based on the amount of oil in the hydraulic chamber 19 of the hydraulic servo mechanism 13, the thrust that moves the movable sheave 12 of the primary pulley 9 in the axial direction is adjusted. Further, the thrust (clamping pressure) for moving the movable sheave 15 of the secondary pulley 10 in the axial direction is adjusted by the hydraulic pressure of the hydraulic chamber 100 of the hydraulic servo mechanism 16. The width of the groove M1 changes according to the operation of the movable sheave 12 in the axial direction, and the width of the groove M2 changes according to the operation of the movable sheave 15 in the axial direction.

  When the width of the groove M1 is adjusted as described above, the ratio between the winding radius of the belt 17 in the primary pulley 9 and the winding radius of the belt 17 in the secondary pulley 10 changes. As a result, the ratio of the rotational speeds between the primary shaft 7 and the primary pulley 9, and the secondary shaft 8 and the secondary pulley 10, that is, the gear ratio changes. Specifically, when the amount of oil in the hydraulic chamber 19 is increased and the width of the groove M1 is narrowed, the winding radius of the belt 17 in the primary pulley 9 is increased, and the gear ratio of the belt-type continuously variable transmission 6 is decreased. Shift so that In this way, a shift that reduces the gear ratio is an upshift. On the other hand, when the amount of oil in the hydraulic chamber 19 is reduced and the width of the groove M1 is widened, the winding radius of the belt 17 in the primary pulley 9 is reduced, and the gear ratio of the belt-type continuously variable transmission 6 is increased. Shift so that Thus, a shift that increases the gear ratio is a downshift. In either the downshift or the upshift, the actual gear ratio and the target gear ratio of the belt type continuously variable transmission 6 can be controlled continuously, in other words, continuously.

  On the other hand, in the secondary pulley 10, when the width of the groove M <b> 2 is adjusted, the clamping pressure applied to the belt 17 and the tension of the belt 17 change, and torque transmitted between the primary shaft 7 and the secondary shaft 8. Capacity is controlled. Specifically, when the hydraulic pressure in the hydraulic chamber 100 of the hydraulic servo mechanism 16 is increased and the clamping pressure applied to the belt 17 increases, the torque capacity of the belt 17 increases. On the other hand, when the hydraulic pressure in the hydraulic chamber 100 of the hydraulic servo mechanism 16 decreases and the clamping pressure applied to the belt 17 decreases, the torque capacity of the belt 17 decreases.

  A correspondence relationship between the control of the belt type continuously variable transmission 6 as described above and a signal input to the electronic control unit 52 will be described. First, when the first drive position or the second drive position is selected and the automatic shift mode is selected, the vehicle speed, a signal indicating an acceleration request, and a shift map stored in the electronic control unit 52 are displayed. Based on this, the target speed ratio of the belt type continuously variable transmission 6 is calculated, and feedback control is performed to bring the actual speed ratio of the belt type continuously variable transmission 6 closer to the target speed ratio. The vehicle speed is calculated based on the rotation speed of the secondary shaft 8. When this automatic transmission mode is selected, the gear ratio of the belt-type continuously variable transmission 6 is controlled so that the operating state of the engine 1 is along the optimum fuel consumption line. This optimum fuel consumption line is set with engine output, that is, torque and rotation speed as parameters.

  Both the first drive position and the second drive position are positions for controlling the forward / reverse switching mechanism 5 so that torque in a direction for moving the vehicle Ve forward can be transmitted to the wheels 2. The gear ratio that can be selected by the belt-type continuously variable transmission 6 is different between the first drive position and the second drive position. Specifically, even if the vehicle speed is the same, the selectable gear ratio differs between the first drive position and the second drive position. As a result, the first drive position and the second drive position differ in vehicle speed at which engine braking force is generated during repulsive driving, strength of engine braking force, or the like. Therefore, when switching is performed between the first drive position and the second drive position, the gear ratio may be switched even if the vehicle speed and the accelerator opening are the same.

  Next, a case where the manual transmission mode is selected will be described. When this manual shift mode is selected, step shift operation and continuous shift operation can be selected. The step shift operation means an operation of pressing the downshift button 51A or the upshift button 51B for a short time that is a predetermined time or less. The continuous speed change operation means an operation of pressing the downshift button 51A or the upshift button 51B for a long time exceeding a predetermined time. Thus, when the manual transmission mode is selected, the target transmission ratio of the belt-type continuously variable transmission 6 is selected by operating the transmission ratio selection device 53.

  When the step shift operation is executed, a plurality of shift speeds set in advance in the electronic control unit 52 as the target gear ratio of the belt-type continuously variable transmission 6, for example, the first to seventh shift speeds, for example. It is possible to select a gear ratio corresponding to any of the above. The first to seventh speed gears are terms that divide different gear ratios in stages. A mode in which feedback control for bringing the actual speed ratio of the belt-type continuously variable transmission 6 closer to the target speed ratio selected by the step speed change operation is referred to as a step speed change mode.

  Here, the speed ratio corresponding to the first speed is larger than the speed ratio corresponding to the second speed, the speed ratio corresponding to the second speed is larger than the speed ratio corresponding to the third speed, and the third speed The gear ratio corresponding to the fourth speed is larger than the gear ratio corresponding to the fourth speed, the gear ratio corresponding to the fourth speed is larger than the gear ratio corresponding to the fifth speed, and the gear ratio corresponding to the fifth speed is The gear ratio corresponding to the sixth speed is larger than the gear ratio corresponding to the seventh speed.

  As described above, when the step shift operation is executed, a gear ratio corresponding to any one of the gear stages is selected as the target gear ratio of the belt-type continuously variable transmission 6, and the step shift mode is executed. That is, the driver can intentionally select a gear ratio similar to a stepped (multistage) automatic transmission in which the gear ratio is changed stepwise, in other words, discontinuously. Here, in the shift control based on the step shift operation, the belt-type continuously variable transmission is set to a gear ratio (intermediate gear ratio) corresponding to a gear ratio (reference gear ratio) corresponding to a preset gear position. The gear ratio of the machine 6 is not fixed.

  On the other hand, when a continuous speed change operation is executed, it is possible to select a speed ratio corresponding to each speed stage from the first speed to the seventh speed as the target speed ratio of the belt-type continuously variable transmission 6. In addition, it is possible to select a gear ratio corresponding to the gear ratios corresponding to the first to seventh gears as the target gear ratio. In either the automatic transmission mode or the manual transmission mode, the actual transmission ratio of the belt-type continuously variable transmission 6 is determined from the vehicle speed, the rotation speed of the primary shaft 7 (input rotation speed), the rotation speed of the secondary shaft 8, and the like. Is done. Further, when feedback control is performed to bring the actual speed ratio of the belt-type continuously variable transmission 6 close to the target speed ratio, specific examples of control amount, target value, disturbance, and the like will be described. Correspondingly, the target gear ratio corresponds to the “target value”, and the energization current to the linear solenoid valve corresponds to the “operation amount”. In addition, the vehicle Ve travels on a rough road and the vehicle Ve vibrates and the actual input rotation speed fluctuates. The vehicle Ve travels on a low friction coefficient road and the wheels 2 slip, and the actual input rotation speed is Fluctuation and the fact that the oil viscosity in the hydraulic circuit fluctuates due to temperature change corresponds to “disturbance”.

  Next, a specific example of feedback control executed when the actual speed ratio of the belt type continuously variable transmission 6 is brought close to the target speed ratio will be described based on the flowchart of FIG. When the feedback control program is started, it is determined whether or not a condition for changing the speed ratio of the belt type continuously variable transmission 6 in a stepwise manner is satisfied (step S1). Here, “the gear ratio of the belt type continuously variable transmission 6 is changed stepwise” means that “the difference between the target gear ratio selected last time and the target gear ratio selected this time is a predetermined value or more. Means "."

Examples of cases where an affirmative determination is made in step S1 include the following cases.
(First case) When the manual shift mode is selected and the step shift operation is executed.
(Second case) When the automatic transmission mode is selected and the first drive position and the second drive position are switched to each other.
(Third case) When the automatic transmission mode is selected and the acceleration request increases rapidly.

If a negative determination is made in step S1, the control program in FIG. 1 is terminated. On the other hand, when a positive determination is made in step S1, a control deviation necessary for feedback control is calculated (step S2). In the process of step S2, the following equation is used.
NINTD = NINT-NIN
Here, NINTD is a control deviation, NINT is a target input rotational speed, and NIN is an actual input rotational speed.

Subsequent to step S2, the amount of change in control deviation is calculated (step S3). The amount of change in the control deviation is obtained by the following equation.
NINTDD = NINTD (i−1) −NINTD (i)
Here, NINTDD is the amount of change in the control deviation, NINTD (i−1) is the control deviation calculated in the previous routine, and NINTD (i) is the control deviation calculated in the current routine.

Following this step S3, an integral term (I term) is calculated from the control deviation amount. That is, the integration time required for the integration operation is obtained (step S4). Here, the gain of the integral term may be a constant value or may be determined based on the control deviation. Following this step S4, a proportional term (P term) is calculated based on the control deviation amount and the integration time (step S5). Following this step S5,
LO ≦ NINTDD ≦ HI
Is determined (step S6).
Here, LO is a lower limit value of the change amount of the control deviation, and HI is an upper limit value of the change amount of the control deviation.

  If the determination in step S6 is affirmative, the PI control flag including the proportional action and the integral action is turned on (step S7), and feedback control using the PI control is executed (step S8). The control program is terminated. On the other hand, if a negative determination is made in step S6, it is determined whether PI control is currently being executed (step S9). If a negative determination is made in step S9, the PI control flag is turned off (step S10), and the above-described integral term is cleared or addition of the integral term is stopped (step S11). Subsequent to step S11, feedback control is executed using P control that does not include integral operation and also includes proportional operation (step S12), and the control program of FIG. 1 ends.

On the other hand, if a positive determination is made in step S9,
NINTDD ≦ LO HIS
Is determined (step S13). Where LO HIS is a hysteresis corresponding to the lower limit value of the change amount of the control deviation,
LO> LO HIS
There is a relationship. If a negative determination is made in step S13,
NINTDD ≧ HI HIS
Is determined (step S14). Where HI HIS is a hysteresis corresponding to the upper limit of the amount of change in control deviation.
HI <HI HIS
There is a relationship.

  If a negative determination is made in step S14, the process proceeds to step S8. On the other hand, if a positive determination is made in step S13 or step S14, the process proceeds to step S10.

  An example of a time chart corresponding to the control example of FIG. 1 will be described with reference to FIG. The time chart of FIG. 3 shows a case where the manual shift mode is selected and a step shift operation (downshift) is performed. In FIG. 3, the target input rotational speed and the actual input rotational speed are shown as the rotational speed of the primary shaft 7 (input shaft rotational speed). Furthermore, states such as a control deviation, a change amount of the control deviation, and a PI control flag are shown. First, before the time t1, the manual shift mode is not selected. Further, since the target input rotational speed and the actual input rotational speed are the same, the control deviation and the change amount of the control deviation are zero. Further, the PI control flag is turned off.

  When a shift change is executed at time t1 and the manual shift mode is selected, the target input rotation speed indicated by the solid line increases, but the actual input rotation speed is a value before time t1. For this reason, the control deviation increases to the positive side, and the change amount of the control deviation increases to the negative side. And from time t1 to time t2, the change amount of the control deviation changes so as to approach zero. Further, before the time t2, the actual input rotational speed increases and the change amount of the control deviation shifts to the positive side. From time t1 to time t2, the change amount of the control deviation is less than the lower limit value of the change amount of the control deviation, and the P control is executed. The situation and control between time t1 and time t2 correspond to the routines of steps S6, S9, S10, S11, and S12.

  When the change amount of the control deviation reaches the lower limit value of the change amount of the control deviation at time t2, the PI control flag is turned on and PI control is executed. After time t2, the control deviation changes so as to approach zero, becomes substantially constant, and the change amount of the control deviation is also substantially constant. From time t2 to time t3, the change amount of the control deviation is less than or equal to the upper limit value of the change amount of the control deviation and greater than or equal to the lower limit value of the change amount of the control deviation. And the PI control is continuously executed. The situation and control from time t2 to time t3 correspond to the routines of steps S6, S7, and S8. Note that, from time t2 to time t3, the actual input rotation speed of the embodiment indicated by the broken line changes so as to approach the target input rotation speed indicated by the solid line. At time t3, the manual transmission mode is switched to the automatic transmission mode, the PI control flag is turned off, and the actual input rotational speed matches the target input rotational speed.

  Here, a case will be described in which the amount of change in the control deviation changes from within the PI control flag on region to outside the PI control flag on region between time t2 and time t3 during which PI control is executed. In this case, if the amount of change in the control deviation exceeds the lower limit hysteresis and is less than the upper limit hysteresis, the PI control is continued. Such a change in the amount of change in the control deviation and a control corresponding to the change in the amount of change in the control deviation correspond to the routines of steps S6, S9, S13, S14, and S8.

  On the other hand, the PI control flag is turned off when the change amount of the control deviation changes below the hysteresis of the lower limit value or when it changes above the hysteresis of the upper limit value. Such a change in the amount of change in the control deviation and a control corresponding to the change in the amount of change in the control deviation correspond to the routines of steps S6, S9, S13, S14, S10, S11, and S12.

  As described above, in this embodiment, when the condition for changing the speed ratio of the belt type continuously variable transmission 6 in a stepwise manner is satisfied, when the amount of change in the control deviation is small, that is, for executing feedback control. When it is considered that the control system is stable, PI control is executed. For this reason, it is possible to remove the steady deviation generated when the P control is executed by the I control. Therefore, it is possible to improve the actual speed ratio with respect to the target speed ratio, in other words, the followability and convergence of the actual speed ratio with respect to the target input rotation speed. For example, there is no possibility of causing a phenomenon in which the actual input rotation speed is repeatedly increased or decreased with the target input rotation speed as a boundary, that is, a so-called hunting phenomenon, when the actual input rotation speed approaches the target input rotation speed. Furthermore, it is possible to prevent the gear ratio from rapidly changing due to a sudden increase in the I term. Incidentally, in FIG. 3, the actual input rotational speed when P control is continued after time t2 (comparative example) is indicated by a one-dot chain line. As described above, the deviation between the actual input rotation speed and the target input rotation speed when the control of the embodiment is executed is smaller than the deviation between the actual input rotation speed and the target input rotation speed in the control of the comparative example.

  In the above embodiment, the case where the transmission ratio of the belt type continuously variable transmission 6 is controlled based on the amount of oil in the hydraulic chamber 19 is described. However, the belt type is controlled based on the hydraulic pressure in the hydraulic chamber 19. It is also possible to control the gear ratio of the continuously variable transmission 6. It is also possible to control the gear ratio of the belt type continuously variable transmission 6 based on the hydraulic pressure or the oil amount in the hydraulic chamber 100. In this case, the torque capacity of the belt type continuously variable transmission 6 can be controlled based on the oil amount or the hydraulic pressure in the hydraulic chamber 19. The belt-type continuously variable transmission 6 having such a configuration can also execute the control example of FIG. Further, in this embodiment, the “rotation speed” is used for feedback control of the gear ratio of the belt-type continuously variable transmission 6, but the “rotation speed”, which is a parameter equivalent to the rotation speed, may be used. Is possible.

  Further, in FIG. 2, a belt-type continuously variable transmission 6 is shown as a continuously variable transmission, but the control of FIG. 1 is applied to a vehicle having another continuously variable transmission, for example, a toroidal continuously variable transmission. An example can also be applied. This toroidal-type continuously variable transmission is a transmission having an input disk and an output disk having toroidal surfaces, and a power roller in contact with each disk. The input disk is connected to the input rotating member, and the output disk is connected to the output rotating member. Lubricating oil is present on the contact surface between each disk and the power roller. Then, the power roller is moved linearly in a plane perpendicular to the axis of each disk, and the contact radius between the power roller and each disk is adjusted to change the speed between the input rotating member and the output rotating member. The ratio is controlled. Moreover, the capacity | capacitance of the torque transmitted between an input rotation member and an output rotation member is controlled by adjusting the contact surface pressure of each disk and a power roller. In addition, the invention according to the claims can be implemented even if the actuator that controls the gear ratio of the continuously variable transmission is a hydraulic actuator, a pneumatic actuator, an electromagnetic actuator, or the like. It is.

  Here, the correspondence between the functional means shown in FIG. 1 and the configuration of the present invention will be described. Steps S2 and S3 correspond to the deviation judging means of the present invention, and steps S4 to S14 are This corresponds to the control switching means of the present invention. Further, when the process proceeds to step S8 via steps S6 and S7, or when the process proceeds from step S9 to steps S8 via steps S13 and S14, the “change degree of deviation is within a predetermined range” of the present invention. Corresponds to “case”. Furthermore, the case of proceeding to steps S10, S11, and S12 via steps S6 and S9 corresponds to “when the change degree of deviation is outside the predetermined range” of the present invention. That is, in this embodiment, the predetermined range is determined based on the upper limit value and lower limit value of the variation amount of the control deviation, hysteresis, and the like. Further, the amount of change in the control deviation corresponds to the “degree of change in deviation” of the present invention. Further, the belt type continuously variable transmission and the toroidal type continuously variable transmission correspond to the continuously variable transmission of the present invention. In this embodiment, the target input speed and the actual input speed are used instead of the target speed ratio and the actual speed ratio.

  Furthermore, “deviation judgment means” described in each claim of the claims is read as “deviation judgment device” or “deviation judgment controller”, and “control switching means” is replaced with “control switching device” or It can also be read as “control switching controller”. In this case, the electronic control device 52 corresponds to a deviation determining device, a deviation determining controller, a control switching device, and a control switching controller. Furthermore, “deviation judgment means” described in each claim of the claims is read as “deviation judgment step”, and “control device for continuously variable transmission” is replaced with “control method for continuously variable transmission”. It is also possible to read “

It is a flowchart which shows the example of control of this invention. It is a conceptual diagram which shows the power train and control system of the vehicle which can apply the control apparatus of this invention. It is a time chart corresponding to the control example of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Wheel, 6 ... Belt-type continuously variable transmission, 52 ... Electronic control apparatus.

Claims (2)

In a transmission control device for a continuously variable transmission that executes feedback control for bringing an actual gear ratio closer to a target gear ratio,
Deviation judging means for judging the degree of change in deviation between the target gear ratio and the actual gear ratio;
A continuously variable transmission having a feedback control including a proportional action and a control switching means for selectively switching between a feedback control including a proportional action and an integral action based on a determination result of the deviation judging means. Shift control device.   When the variation degree of the deviation is outside the predetermined range, the feedback control including the proportional operation is selected. When the variation degree of the deviation is within the predetermined range, the feedback control including the proportional operation and the integral operation is selected. The shift control device for a continuously variable transmission according to claim 1, wherein the control switching means has a function.

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