JP2005315320A - Transmission control device of vehicle driving device by continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission control device of a vehicle driving device for performing a control mode considered to be desirable in taking the manual change control of a change gear ratio into account in an automatic transmission control of a continuously variable transmission. <P>SOLUTION: In this transmission control device of the vehicle driving device including the continuously variable transmission, when setting of a change gear ratio is changed like steps by manual operation, the target values of initial step-like change of the change gear ratio and the subsequent gradual change of the change gear ratio are calculated, and when the engine rotating speed corresponding to the result of the initial step-like change of the change gear ratio is outside of its allowable rotating speed range, the target value of the change gear ratio is set to such a value that the engine rotating speed is a limit value of the allowable rotating speed range to control the change of gear change ratio. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transmission control device for a continuously variable transmission, and more particularly to a transmission control device for a vehicle drive device in which a continuously variable transmission is incorporated between an engine and wheels.

  There is known a continuously variable transmission in which the ratio of the rotational speed of the input rotational element to the rotational speed of the output rotational element is continuously variable, such as a V-belt transmission or a toroidal transmission. It is also known that a vehicle drive device is configured by being incorporated between the wheel and the wheel. In general, the vehicle is operated in such a way that the driver obtains a desired vehicle speed and adjusts the amount of depression of the accelerator pedal and the brake pedal. At this time, the vehicle speed obtained for the amount of depression of the accelerator pedal and the amount of depression of the brake pedal is adjusted. Since the vehicle load status and the road conditions that change from moment to moment are reflected, the gear ratio that optimally controls the gear ratio of the continuously variable transmission according to the combination of the vehicle speed and the depression amount of the accelerator pedal or brake pedal is set. The gear ratio schedule is determined in advance, and the optimum gear ratio of the continuously variable transmission at that time is obtained by referring to the gear ratio schedule from the vehicle speed and the amount of depression of the accelerator pedal or the brake pedal from time to time. Calculate the desired rotation speed of the input rotation element of the continuously variable transmission as the target rotation speed, and adjust the actual rotation speed of the input rotation element to the target rotation speed. By controlling the transmission ratio of the continuously variable transmission so that, vehicle optimal operation of is achieved for the transmission ratio.

However, the driver sometimes desires driving with a gear ratio different from the automatic gear ratio schedule. In such a case, there is provided target value setting means for setting a target value of the shift control based on the signal of the manual shift command means, and the continuously variable transmission has priority over the automatic shift control based on the signal from the target value setting means. A shift control device for a continuously variable automatic transmission that controls the shift control amount is described in Patent Document 1 below. In this patent document, as a mode of the control, it is determined whether the manual shifting operation lever is operated within a predetermined time which is considered to be an extremely short time or continuously operated over a longer time. Is within a predetermined time, the target gear ratio is changed by a predetermined amount by one step, and when the operation lever is continuously operated, the target gear ratio is continuously changed by a minute amount. It is described that when the engine rotational speed to be exceeded exceeds the allowable limit, the target speed ratio is corrected to the speed ratio corresponding to the allowable limit. Further, in Patent Document 2 below, in a transmission having a plurality of gear stages with a fixed gear ratio, a gear stage that can be selected from an allowable engine speed is displayed, and a gear stage that cannot be selected by a gear shifting operation is displayed. It is described that, when is selected, an alarm is issued without shifting.
JP-A-9-217799 Japanese Patent Laid-Open No. 10-175461

  According to the manual gear ratio change control during automatic transmission control of the continuously variable transmission described in Patent Document 1, the predetermined time for determining whether the operation of the manual transmission operation lever is temporary or continuous is short. Therefore, even when the driver operates the operation lever with the intention of temporary operation, it is determined that the operation is a continuous operation, and as soon as the control for changing the gear ratio by a minute amount is started, the speed change control is performed. There is a possibility that it will be canceled, and if the predetermined time is lengthened, it seems that there is a problem that the response of the shift control corresponding to the manual shift operation is delayed.

  The present invention contemplates a control mode that is desirable in considering the above-described circumstances and manual shift ratio change control in addition to automatic transmission control of a continuously variable transmission, and provides a shift control apparatus for a vehicle drive device that executes the control mode. The issue is to provide.

  In order to solve the above problems, the present invention provides a vehicle drive in which a continuously variable transmission capable of continuously changing the ratio of the rotational speed of the input rotational element to the rotational speed of the output rotational element is incorporated between the engine and the wheel. When the ratio setting is changed stepwise by manual operation in the transmission control device of the apparatus, the initial step change of the ratio and the subsequent target value of the gradual change of the ratio are calculated, and the ratio is When the engine speed corresponding to the result of the initial step change is outside the allowable rotational speed range of the engine, the target value of the ratio is set to the limit value of the allowable rotational speed range. The transmission control apparatus is characterized in that the ratio is changed and controlled to be set to a value.

  The shift control apparatus as described above may execute the manual operation when controlling the ratio by limiting the target value of the ratio to a value at which the engine rotational speed is a limit value of the allowable rotational speed range. May be displayed to the person. In this case, the display may be performed with a delay time until the control of the ratio is completed by limiting the target value of the ratio to a value corresponding to the limit value.

  Further, in particular, the step-like change in the ratio setting by the manual operation is an upshift that lowers the ratio, and the target value of the ratio with the engine rotation speed as the limit value of the allowable rotation speed range is the engine May be a value that sets the minimum rotational speed at which the engine can maintain a stable operation.

  In addition, even if the engine rotation speed corresponding to the result of the ratio having undergone the initial step change is within the allowable rotation speed range of the engine, the ratio gradually changes following the initial step change of the ratio. When the rotation speed of the corresponding engine is out of the allowable rotation speed range of the engine, the change of the ratio may be stopped.

  In a speed change control device for a vehicle drive device in which a continuously variable transmission capable of continuously changing the ratio of the rotational speed of the input rotary element to the rotational speed of the output rotary element is installed between the engine and the wheel, the ratio is manually controlled. When the setting is changed to a step, the target value of the initial step change of the ratio and the subsequent gradual change of the ratio is calculated, and the engine corresponding to the result of the ratio making the initial step change is calculated. When the rotational speed is out of the allowable rotational speed range of the engine, the target value of the ratio is set to a value at which the rotational speed of the engine becomes the limit value of the allowable rotational speed range, and the ratio is controlled to be changed. Therefore, considering that the gear ratio setting change made by manual operation is naturally a step, the step change request is divided into the initial step change and the subsequent gradual change of the gear ratio. By setting the target value based on the control calculation, it is possible to harmonize the quickness and smoothness of the response to the manual operation input, and further, the initial step change of the gear ratio that is performed at once is performed. If the engine speed corresponding to the result of the operation is outside the allowable engine speed range, the target value of the gear ratio should be set to a value at which the engine speed is the limit value of the allowable engine speed range. Thus, it is possible to prevent the engine rotational speed from being out of the allowable rotational speed range due to an unreasonable manual change of the gear ratio, and to ensure stable operation of the vehicle.

  In such a gear ratio control, when the gear ratio is controlled by limiting the target value of the gear ratio to a value at which the engine speed becomes the limit value of the allowable speed range, this is designated as a manual operator. If the manual shift command issued by the user, that is, the driver of the vehicle, is an unreasonable request to drive the engine rotational speed out of the allowable rotational speed range. In addition, it is possible to know that the manual shift command is not executed as it is, and the vehicle can be driven more stably. In this case, if the display is performed with a delay time until the control of the target value of the gear ratio as a value corresponding to the allowable limit value of the engine speed is completed, the display to the driver is quick. Thus, it is possible to avoid the inconvenience that the driver is prompted to change the command and the control result is not consistent with the change command.

  When the step change in the gear ratio setting by manual operation is an upshift that lowers the gear ratio, the engine speed is at least temporarily reduced by executing it, so the engine speed is stable. If the engine speed is reduced to below the minimum speed at which it is possible to maintain the operation, there is a risk of rough engine rotation or stoppage. If the control is automatically corrected so that the engine speed reaches the lowest speed at which the engine can maintain stable operation, the engine will operate stably regardless of the manual gear ratio change operation. Can be secured.

  Further, even if the engine speed corresponding to the result of the gear ratio having undergone the initial step change described above is within the allowable engine speed range, it corresponds to the result of the gradual change following the initial step change of the gear ratio. If the change of the gear ratio is to be stopped when the engine speed is outside the allowable engine speed range, an inappropriate change to the engine speed can be made by executing a manual gear ratio change command. Can be prevented from happening.

  FIG. 1 attached herewith is a schematic diagram showing an example of a vehicle drive device that includes a belt-type continuously variable transmission and is controlled by a shift control device according to the present invention. In the figure, 10 is an engine, and its crankshaft 12 drives a pump 16 of a torque converter 14, thereby driving a turbine 18 and driving a torque converter output shaft 22 via a buffer joint 20, When the direct coupling clutch 24 is engaged, the torque converter is bypassed and the torque converter output shaft 22 is directly driven via the buffer joint 20. A stator 26 of the torque converter is supported by the housing 30 via a one-way clutch 28. The torque converter output shaft 22 is connected to the rotary frame 32, is connected to the intermediate shaft 36 via the clutch 34, and is also connected to the ring gear 40 of the planetary gear unit 38. The sun gear 42 of the planetary gear device is connected to the intermediate shaft 36. A planetary pinion 46 carried by a carrier 44 is meshed between the ring gear 40 and the sun gear 42 of the planetary gear device. The carrier 44 is supported from the housing 50 so as to rotate concentrically with the intermediate shaft 36 by a brake 48, and at the same time, the carrier 44 is selectively prevented from rotating. The brake 48 is engaged when the vehicle moves backward, and prevents the carrier 44 from rotating and reverses the intermediate shaft 36.

  A fixed primary sheave 52 of a continuously variable transmission (CVT) indicated by 51 as a whole is fixed to the intermediate shaft 36. Therefore, the intermediate shaft 36 is a continuously variable transmission having the primary sheave 52 as an input rotation element. It is an input axis. A movable primary sheave 58 that presents a conical belt engaging surface 56 opposite to the conical belt engaging surface 54 of the fixed primary sheave 52 is movable along the axial direction on the intermediate shaft 36, but by a spline. It is installed in the relationship of transmitting torque. The movable primary sheave 58 is provided with a hydraulic cylinder 60, a piston 62 is engaged with the hydraulic cylinder, and a hydraulic chamber 64 is formed between the piston and the movable primary sheave 58. The piston 62 is fixed on the intermediate shaft 36 and rotates integrally therewith. Therefore, the piston 62 is engaged with the hydraulic cylinder 60 fixed to the movable primary sheave 58 in the hydraulic chamber. While changing the volume of 64 appropriately, it rotates integrally with the movable primary sheave 58. Pressure oil is supplied to the hydraulic chamber 64 from the port 66 through the oil passage 68, or the oil in the hydraulic chamber 64 is discharged from the port 66 through the oil passage 68. The intermediate shaft 36 is rotatably supported by a bearing means (not shown) from a housing (not shown).

  An output shaft 70 is arranged in parallel with the intermediate shaft 36 and is spaced apart from the intermediate shaft 36, and is rotatably supported by a bearing means (not shown) from a housing (not shown). A fixed secondary sheave 72 is fixed to the output shaft 70. A movable secondary sheave 78 is movable on the output shaft 70 along its axial direction so as to present a conical belt engaging surface 76 opposite to the conical belt engaging surface 74 of the fixed secondary sheave 72, but It is installed in the relationship of transmitting torque by spline. The movable secondary sheave 78 is provided with a hydraulic cylinder 80, and a piston 82 is engaged with the hydraulic cylinder, and a hydraulic chamber 84 is formed between the piston and the movable secondary sheave 78. The piston 82 is fixed on the output shaft 70 and rotates integrally therewith. Therefore, the piston 82 is engaged with the hydraulic cylinder 80 fixed to the movable-side secondary sheave 78, so that the hydraulic chamber While changing the volume of 84 as appropriate, it rotates integrally with the movable secondary sheave 78. Pressure oil is supplied to the hydraulic chamber 84 from the port 86 through the oil passage 88, or the oil in the hydraulic chamber 84 is discharged from the port 86 through the oil passage 88.

  A groove having a V-shaped cross section formed by the conical belt engaging surface 54 of the fixed primary sheave 52 and the conical belt engaging surface 56 of the movable primary sheave 58 and the conical belt engaging surface 74 of the fixed secondary sheave 72. An endless belt 90 is wound around a groove having a V-shaped cross section formed by the conical belt engaging surface 76 of the movable secondary sheave 78. A gear 92 is attached to the output shaft 70, and a gear 94 is engaged with the gear 92. The gear 94 is attached to one end of a shaft 96 rotatably supported by bearing means (not shown), and a gear 98 is provided at the other end of the shaft. The gear 98 meshes with the input gear 102 of the differential device 100, thereby driving the pair of axles 104 and 106.

  The hydraulic oil is supplied to and discharged from the hydraulic chamber 64 of the movable primary sheave 58 and the hydraulic chamber 84 of the movable secondary sheave 78 by connecting the ports 66 and 86 to the pressure oil source 110 such as a hydraulic pump through the hydraulic switching valve 108. This is done by switching to and connecting to the oil reservoir 112. The hydraulic switching valve 108 includes ports 114 and 116 connected to ports 66 and 86, a port 118 connected to the pressure oil source 110, a port 120 connected to the oil reservoir 112, a valve element 122, a valve, Solenoids 124 and 126 that switch the path pattern of element 122. When neither solenoid 124 or 126 is energized, the passage pattern of the valve element is in the state a, and the communication between ports 116 and 118 and the communication between ports 114 and 120 are both cut off. Yes. When only the solenoid 124 is energized, the passage pattern of the valve element is in the state b, and the ports 116 and 118 are communicated and the ports 114 and 120 are communicated. When only the solenoid 126 is energized, the passage pattern of the valve element is in the state c, and the ports 116 and 120 are communicated, and the ports 114 and 118 are communicated. The gear ratio is kept constant when the passage pattern of the valve element is in the state a, the gear ratio is gradually increased when it is in the state b, and the gear ratio is gradually decreased when it is in the state c.

  The energization of the solenoids 124 and 126 is performed in a pulse manner at a constant cycle, and an electronic type in which a microcomputer is incorporated to determine whether or not a pulse current should be energized to the solenoid 124 or 126 every cycle. This is done by the controller 128. The switching control of the hydraulic switching valve by the pulse current is performed by sorting whether the pulse current should be turned on every cycle, and the number of cycles that are turned on out of a certain number of cycles is the duty ratio. Therefore, it is called duty ratio control. According to such control, if the duty ratio for the solenoid 124 is increased with respect to the duty ratio for the solenoid 126, the speed ratio is increased more quickly according to the increase in the difference, and conversely, the duty ratio for the solenoid 124 is increased. On the other hand, if the duty ratio with respect to the solenoid 126 is increased, the speed ratio is reduced more rapidly as the difference increases.

  In the state shown in the drawing, the hydraulic oil in the hydraulic chamber 64 of the movable primary sheave 58 is largely drained, and the movable primary sheave 58 is far away from the fixed primary sheave 52, and conversely the hydraulic pressure of the movable secondary sheave 78. A large amount of hydraulic oil is supplied to the chamber 84 and the movable secondary sheave 78 is brought closer to the fixed secondary sheave 72, and the gear ratio is almost the maximum value.

  The electronic control device 128 is supplied with various signals I indicating vehicle speed, accelerator pedal depression amount (accelerator opening), brake pedal depression amount (brake hydraulic pressure) and other vehicle driving state information. Based on these information, control calculation is performed according to a control program loaded in advance, and based on the calculation result, the operation of the engine 10, the clutches 24, 34, and 48 is controlled, and the operation of the hydraulic switching valve 108 is controlled, At that time, the control operation according to the present invention is executed.

  FIG. 2 is a flowchart showing one embodiment of the shift control device of the vehicle drive device according to the present invention in its operation mode. Execution determination and determination in each step of the flowchart are performed by the electronic control device 128. Further, the control according to the flowchart is usually repeatedly performed at a cycle of about several tens to 100 milliseconds.

  When the operation of the speed change control device according to the present invention is started as part of the overall operation control of the vehicle, the operation of the vehicle is started by closing the ignition switch not shown in the figure. It is then determined whether or not a manual upshift command has been issued. If the answer is no, the control of this time is terminated as it is, but if the answer is yes, the control proceeds to step 2, and based on various data relating to the driving state of the vehicle and the shift state of the drive system at that time, A target rotational speed Npt for reducing the rotational speed of the primary sheaves 52, 58 in a stepwise manner is calculated.

  Next, the control proceeds to step 3 where the target rotational speed Npt is determined from Npg which is the limit value (in this case, the lower limit value) of the primary sheave speed that can keep the engine speed within the predetermined allowable speed range. It is determined whether or not it is large. If the answer is yes, control proceeds to step 4 where time A is set by a timer incorporated in the electronic controller 128.

  Next, the control proceeds to step 5 where initial step-like shift control is performed in which the gear ratio of the continuously variable transmission 51 is rapidly lowered until the rotation speed of the primary sheaves 52, 58 reaches the target rotation speed Npt. Whether or not the primary sheave rotational speed Np has decreased to the target rotational speed Npt is determined in Step 6, and while the answer is no, the control returns to Step 5 and the upshift of the continuously variable transmission is continued. When the initial step shift is achieved and the answer to step 6 is yes, the control proceeds to step 7.

  In step 7, the target rotational speed Npt of the primary sheave calculated above is reduced by a predetermined minute amount ΔN, and then in step 8, the reduced target rotational speed Npt is calculated as described above. It is determined whether the primary sheave rotation speed is not less than the limit value Npg. While the answer is yes, control proceeds to step 9 where it is determined whether the timer set above has counted up time A. While the answer is no, the control proceeds to Step 10 where the primary sheave rotation speed is reduced to the target value Npt and the control is returned to Step 7 again until the predetermined time set as time A elapses. The speed ratio of the continuously variable transmission is gradually reduced.

  In the meantime, a predetermined time A has elapsed, and it is judged in step 9 or that the target value Npt that is gradually reduced in the middle of the time is not greater than the limit value Npg. Is determined, control proceeds to step 11 where the gradual change upshift of the continuously variable transmission is stopped. At this time, the control further proceeds to step 12, and the setting of time A is cleared.

  If the answer to step 3 is no, the control proceeds to step 13 where the speed ratio of the continuously variable transmission is upshifted in steps until the rotational speed of the primary sheave reaches Npg. In this case, the timer is set to a predetermined time B in the next step 14, and the time B is measured by determining whether or not the time B is counted up in the next step 15. Waiting for the progress, in step 16, a display indicating to the instructor of manual shift is performed that the execution of the upshift commanded manually is incomplete. Also in this case, the control further proceeds to step 17 and the setting of time B is cleared.

  In the above control, time B may be omitted, but in the illustrated embodiment, even when the answer to step 3 is no, an upshift to Npg is performed. The display of the incomplete execution of the upshift to the driver is preferably performed after the execution of the upshift is completed although it is incomplete.

  FIG. 3 shows the manual upshift command signal when the control is executed in the manner shown in the flowchart of FIG. 2, the change in the rotation speed of the primary sheave based on it, and the progress of the incomplete upshift display to the driver. It is a graph. As shown in the figure, even if the primary sheave target rotational speed Npt by the manual command is indicated by a virtual line, the value is suppressed to the value of Npg as indicated by the solid line. Note that the curve indicated by the broken line at the corner of the transition to Npg is the actual change in the primary sheave rotation speed, and the incomplete upshift display is performed at the end of the curve portion. .

  In the above description, an example in which an upshift is commanded by a manual shift command has been described. However, it is obvious that the same control may be performed when a downshift is commanded by a manual shift command. . However, in this case, the allowable limit value of the engine speed is the maximum speed allowed for the engine, the speed allowed for the current engine is quite high, and the speed change that the engine speed reaches such a high speed is high. Since it seems rare to be commanded by manual shifting, the need for such control appears to be fairly low.

  While the present invention has been described in detail with respect to one embodiment thereof, it will be apparent that various modifications can be made within the scope of the present invention.

Schematic which shows an example of the vehicle drive device provided with a belt-type continuously variable transmission and controlled by the transmission control apparatus by this invention. The flowchart which shows the operation example of the transmission control apparatus of the vehicle drive device shown in FIG. The graph which shows progress of the manual upshift command signal in the control shown in the flowchart of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 12 ... Crankshaft, 14 ... Torque converter, 16 ... Pump, 18 ... Turbine, 20 ... Buffer joint, 22 ... Torque converter output shaft, 24 ... Direct coupling clutch, 26 ... Stator, 28 ... One-way clutch, 30 ... Housing, 32 ... rotating frame, 34 ... clutch, 36 ... intermediate shaft, 38 ... planetary gear unit, 40 ... ring gear, 42 ... sun gear, 44 ... carrier, 46 ... planetary pinion pinion, 48 ... brake, 50 ... housing, 51 ... Continuously variable transmission, 52 ... fixed primary sheave, 54, 56 ... belt engagement surface, 58 ... movable primary sheave, 60 ... hydraulic cylinder, 62 ... piston, 64 ... hydraulic chamber, 66 ... port, 68 ... oil passage , 70 ... output shaft, 72 ... fixed side secondary sheave, 74 ... conical belt engaging surface, 76 ... belt engaging surface, 8 ... Moving side secondary sheave, 80 ... Hydraulic cylinder, 82 ... Piston, 84 ... Hydraulic chamber, 86 ..., 88 ... Oil passage, 90 ... Endless belt, 92,94 ... Gear, 96 ... Shaft, 98 ... Gear, 100 ... Differential gear, 102 ... Input gear, 104,106 ... Axle, 108 ... Hydraulic switching valve, 110 ... Pressure oil source, 112 ... Oil reservoir, 114,116,118,120 ... Port, 122 ... Valve element, 124,126 ... Solenoid, 128 ... Electronic control device

Claims (5)

  A continuously variable transmission capable of continuously changing the ratio of the rotational speed of the input rotational element to the rotational speed of the output rotational element is a transmission control device for a vehicle drive device that is incorporated between the engine and the wheel. When the setting is changed stepwise, the target value of the initial step change of the ratio and the subsequent gradual change of the ratio is calculated, and the ratio of the engine corresponding to the result of the ratio making the initial step change is calculated. When the rotational speed is outside the allowable rotational speed range of the engine, the target value of the ratio is set to a value at which the rotational speed of the engine becomes a limit value of the allowable rotational speed range, and the ratio is changed and controlled. A shift control device characterized by the above.   When the ratio is controlled by limiting the target value of the ratio to a value at which the engine rotational speed is the limit value of the allowable rotational speed range, this is displayed to the person performing the manual operation. The shift control apparatus according to claim 1, wherein the shift control apparatus is provided.   The speed change according to claim 2, wherein the display is performed by taking a delay time until the control of the ratio is completed by limiting the target value of the ratio to a value corresponding to the limit value. Control device.   The step change of the ratio setting by the manual operation is an upshift to lower the ratio, and the target value of the ratio with the engine rotation speed as the limit value of the allowable rotation speed range is the engine rotation speed. The speed change control device according to any one of claims 1 to 3, wherein the shift control device has a value that is a minimum rotation speed at which the engine can maintain a stable operation. Even if the engine speed corresponding to the result of the ratio having undergone the initial step change is within the allowable rotational speed range of the engine, the ratio corresponds to the result of the gradual change following the initial step change of the ratio. The speed change control device according to any one of claims 1 to 4, wherein the change of the ratio is stopped when the rotational speed of the engine falls outside an allowable rotational speed range of the engine.

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