JP4349959B2 - Belt type continuously variable transmission - Google Patents

Description

  The present invention relates to a belt-type continuously variable transmission that enables a stepless speed change by changing the groove width of each pulley based on the thrust of a driving pulley and a driven pulley that span the belt.

  In the belt type continuously variable transmission, since power is transmitted by a belt stretched between a driving pulley and a driven pulley, it is important to prevent the belt from slipping. For this reason, in the conventional belt type continuously variable transmission, the driven pulley thrust that can be held by the driven pulley without slipping the belt is calculated as the target driven pulley thrust, and the drive pulley is installed based on the target driven pulley thrust. Some attempt to prevent belt slippage by calculating a target drive pulley thrust (see, for example, Patent Document 1).

JP 2000-18347 A

  However, the prior art described in the above document sometimes subtracts a correction value based on the target gear ratio or target gear speed from the target driven pulley thrust to achieve the target driving pulley thrust. If the driving pulley does not slide the belt below the limit value, the belt may slip, resulting in poor shifting.

  Therefore, in the above prior art, after calculating the target drive pulley thrust, it is determined whether the target drive pulley thrust is a predetermined value or less. If the target drive pulley thrust is a predetermined value or less, the drive pulley slides the belt. The drive pulley thrust that can be pinched without being recalculated is recalculated as a new target drive pulley thrust, and the target driven pulley thrust is newly recalculated based on the target drive pulley thrust.

  However, in the above prior art, the calculation method of the target drive pulley thrust and the target driven pulley thrust is classified according to the determination result of whether or not the target drive pulley thrust is a predetermined value or less. The thrust and the driven pulley thrust change discontinuously, and the smoothness of the original speed change of the continuously variable transmission is impaired, resulting in inconvenience for the driver and the like.

  In addition, the above-described prior art calculates the target drive pulley thrust based on the target driven pulley thrust, and if the target drive pulley thrust is a predetermined value or less, the target drive pulley thrust and the target driven pulley thrust are calculated again. Therefore, calculation of the target drive pulley thrust and the target driven pulley thrust is inconvenient.

  The present invention has been made in view of these facts, and an object of the present invention is to provide a belt-type continuously variable transmission capable of realizing smooth shifting without causing belt slippage without complicated processes. To do.

  According to the first aspect of the present invention, a driving pulley thrust for generating a target driving pulley thrust for realizing a target gear ratio by passing a belt between the driving pulley and the driven pulley and sandwiching the belt with the driving pulley. A belt type continuously variable transmission comprising: generating means; and driven pulley thrust generating means for generating a target driven pulley thrust for realizing a target gear ratio by sandwiching the belt between the driven pulleys. A steady driving pulley thrust calculating means for calculating a steady driving pulley thrust required to hold the belt without slipping and maintain the current gear ratio; and the driven pulley to grip the belt without slipping A steady driven pulley thrust calculating means for calculating a steady driven pulley thrust required to maintain the gear ratio, and required to achieve a target shift speed; A speed change pulley thrust difference calculating means for calculating a target speed change pulley thrust difference between the dynamic pulley thrust and the driven pulley thrust, and a speed change in the drive pulley or the driven pulley based on the difference between the target speed change ratio and the actual speed change ratio. A gear ratio feedback pulley thrust difference calculating means for calculating a ratio feedback pulley thrust difference, a gear shift thrust obtained by adding the target gear speed pulley thrust difference and the gear ratio feedback pulley thrust difference, and a predetermined value; If the shift thrust exceeds a predetermined value, the steady drive pulley thrust and the absolute value of the shift thrust are added to obtain the target drive pulley thrust, and the steady driven pulley thrust is converted to the target driven pulley thrust. When the shift thrust is not more than a predetermined value, the steady drive pulley thrust is set as the target drive pulley thrust and the steady slave In which by adding the absolute value of the pulley thrust and the speed change thrust, characterized in that it comprises a target pulley thrust calculation means and the target driven pulley thrust.

  According to a second aspect of the present invention, in the first aspect, the shift speed pulley thrust difference calculation means is a fuel efficiency command means for instructing that fuel efficiency is required, and the speed change speed according to the fuel efficiency request command. And a pulley speed difference limiting means for shifting speed for limiting the pulley thrust difference.

  According to the first aspect of the present invention, the actual speed ratio is made to coincide with the target speed ratio based on the difference between the pulley thrust force for speed change required to achieve the target speed change and the difference between the actual speed ratio and the target speed ratio. By adding the gear shift thrust to either the steady drive pulley thrust or the steady driven pulley thrust after classifying the cases based on the gear shift thrust obtained by adding the gear ratio feedback pulley thrust difference required for Since the target driving pulley thrust and the target driven pulley thrust can be calculated independently of each other, the target pulley thrust that does not slide the belt against one of the driving pulley or the driven pulley is calculated, but the other pulley is calculated. The target pulley thrust calculated in this way does not become the pulley thrust for sliding the belt.

  That is, in the first aspect of the invention, there is no inconvenience of recalculating the target drive pulley thrust and the target driven pulley thrust. Therefore, the actual drive pulley thrust and the driven pulley thrust are changed discontinuously, so that the continuously variable transmission is performed. The smoothness of gear shifting inherent in the machine is impaired and the driver or the like is not discomforted. In addition, the complexity of recalculating the target driving pulley thrust and the target driven pulley thrust can be eliminated.

  Therefore, according to the first aspect of the present invention, smooth shifting without causing belt slip can be realized without complicated steps.

  According to the second aspect of the present invention, if there is a fuel efficiency request command, the target drive pulley thrust and the target driven pulley thrust are calculated by limiting the gear speed pulley thrust difference in accordance with the command. While ensuring the basic performance of achieving the target gear ratio without occurrence, it becomes possible to travel in consideration of fuel efficiency requirements, so that the fuel efficiency can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 schematically shows a V-belt continuously variable transmission according to the present invention. This V-belt continuously variable transmission 1 has a primary pulley 2 and a secondary pulley 3 arranged so that their V-grooves are aligned, The V belt 4 is stretched over the V grooves of the pulleys 2 and 3. The primary pulley 2 arranges the engine 5 coaxially, and a lock-up torque converter 6 and a forward / reverse switching mechanism 7 are sequentially arranged between the engine 5 and the primary pulley 2 from the engine 5 side.

  The rotation to the primary pulley 2 is transmitted to the secondary pulley 3 via the V-belt 4, and the rotation of the secondary pulley 3 thereafter reaches the wheel (not shown) via the output shaft 8, the gear set 9 and the differential gear device 10.

  Among the flanges forming the V-grooves of the primary pulley 2 and the secondary pulley 3 in order to change the rotational transmission ratio (hereinafter referred to as “speed ratio”) between the primary pulley 2 and the secondary pulley 3 during the power transmission. One is fixed flanges 2a and 3a, and the other flanges 2b and 3b are movable flanges that can be displaced in the axial direction. The movable flanges 2b and 3b respectively supply a primary pulley pressure Ppri and a secondary pulley pressure Psec, which are generated using a line pressure controlled as described later as a source pressure, to the primary pulley chamber 2c and the secondary pulley chamber 3c, respectively. A thrust toward the fixed flanges 2a and 3a is generated, and the V-belt 4 is sandwiched between the pulley flanges to enable the power transmission between the primary pulley 2 and the secondary pulley 3.

  However, when shifting, the V grooves of both pulleys 2 and 3 are changed by the differential pressure between the primary pulley pressure Ppri and the secondary pulley pressure Psec generated corresponding to the target gear ratio, as will be described later. The target gear ratio is realized by continuously changing the winding arc diameter of the V belt 4 with respect to the pulleys 2 and 3.

  Outputs of the primary pulley pressure Ppri and the secondary pulley pressure Psec are controlled by a shift control hydraulic circuit 11, which is controlled in response to a signal from the transmission controller 12. Therefore, the transmission controller 12 has a signal from the primary pulley rotation sensor 13 that detects the primary pulley rotation speed Npri, a signal from the secondary pulley rotation sensor 14 that detects the secondary pulley rotation speed Nsec, and the depression of the accelerator pedal. Selection from the manual shift switch 17 that detects the selection from the manual shift mode that gives priority to the shift by the driving operation or the shift command from the transmission controller 12 from the signal from the accelerator pedal stroke sensor 16 that detects the stroke. A mode signal, a selection range signal from the inhibitor switch 17, a brake switch 18 for detecting depression of the brake pedal, and a fuel consumption request signal from the economy mode switch 19 for the driver to request driving with a focus on fuel consumption, D And a signal that relates to the transmission input torque Ti from an engine controller 20 for controlling the Jin 5 (such as engine speed and fuel injection time).

  FIG. 2 is a system diagram showing the transmission control hydraulic circuit 11 and the transmission controller 12. First, the transmission control hydraulic circuit 11 will be described. The circuit 11 includes an oil pump 21 that is driven by an engine. The hydraulic oil from the pump 21 to the oil passage 22 is used as a medium, and the pressure is adjusted to a predetermined line pressure PL by a pressure regulator valve 23.

  One of the line pressures PL of the oil passage 22 is adjusted by the pressure reducing valve 24 as the primary pulley pressure Ppri and supplied to the primary pulley chamber 2C, and the other is adjusted by the pressure reducing valve 25 as the secondary pulley pressure Psec and the secondary pulley chamber 3C. To be supplied. However, the pressure regulator valve 23 controls the line pressure PL by the driving duty to the solenoid 23a, and the pressure reducing valves 24 and 25 respectively control the primary pulley pressure Ppri and the secondary pulley pressure Psec by the driving duty to the solenoids 24a and 25a. To do.

  Further, the solenoid drive duty of the pressure regulator valve 23 and the solenoid drive duty of the pressure reducing valves 24 and 25 are determined by the transmission controller 12. That is, the transmission control hydraulic circuit 11 and the transmission controller 12 correspond to the drive pulley thrust generation means and the driven pulley thrust generation means.

  FIG. 3 is a flowchart showing an example of hydraulic control executed by the transmission controller 12. This flowchart is repeatedly executed every predetermined time, for example, several tens of msec after the engine start is detected by turning on the ignition key or the like. The

  First, in step 1, the primary pulley 2 holds the V belt 4 without slipping, and the steady drive pulley thrust Fpri (f) required to maintain the current gear ratio (actual gear ratio) i and the secondary pulley 3 Calculates the steady driven pulley thrust Fsec (f) required to hold the V belt 4 without slipping and maintain the actual gear ratio i. That is, step 1 corresponds to a steady drive pulley thrust calculation means and a steady driven pulley thrust calculation means. The steady drive pulley thrust Fpri (f) and the steady driven pulley thrust Fsec (f) are calculated using, for example, a subroutine shown in FIG.

  Next, in Step 2, a pulley speed difference F (v) for shifting speed between the primary pulley thrust and the secondary pulley thrust required to achieve the target shifting speed V (I) determined based on the driving state is calculated. calculate. That is, step 2 corresponds to a shift speed pulley thrust difference calculation means. Note that the transmission speed pulley thrust difference F (v) is calculated using, for example, a subroutine shown in FIG.

  In step 3, a gear ratio feedback pulley thrust difference F (fb) in the primary pulley 2 or the secondary pulley 3 is calculated based on the difference between the target speed ratio I and the actual speed ratio i. That is, step 3 corresponds to a gear ratio feedback pulley thrust difference calculation means. Note that the gear ratio feedback pulley thrust difference F (fb) is calculated using, for example, a subroutine shown in FIG.

  In step 4, the speed change pulley thrust difference F (v) calculated in step 2 and the speed ratio feedback pulley thrust difference F (fb) calculated in step 3 are added to obtain the speed change thrust F (th). In step 5, the shift thrust F (th) is compared with a predetermined value F. Specifically, the predetermined value F = 0 is set, and it is determined whether or not the shift thrust F (th) exceeds the predetermined value F = 0.

  If it is determined in step 5 that the shift thrust F (th)> 0, in step 6, the steady drive pulley thrust Fpri (f) calculated in step 1 and the shift thrust F (th) are added. The target drive pulley thrust Fpri (o) (= Fpri (f) + F (th)) is calculated. In step 6, the steady driven pulley thrust Fsec (f) calculated in step 1 is directly used as the target driven pulley thrust Fsec (o) (= Fsec (f)).

  If it is determined in step 5 that the shift thrust F (th)> 0 is not satisfied, in step 8, the steady drive pulley thrust Fpri (f) calculated in step 1 is directly used as the target drive pulley thrust Fpri (= Fpri). (f)). In step 9, the steady driven pulley thrust Fsec (f) calculated in step 1 and the shift thrust F (th) are subtracted, that is, the absolute value of the steady driven pulley thrust Fsec (f) and the shift thrust F (th) | F (th) | is added to calculate the target driven pulley thrust Fsec (o) (= Fsec (f) + | F (th) |).

  In step 10, the target drive pulley pressure Ppri (o) to be regulated by the pressure reducing valve 24 is calculated based on the target drive pulley thrust Fpri (o) calculated in step 6 or 8. Specifically, the target drive pulley pressure Ppri (o) is calculated by dividing the target drive pulley thrust Fpri (o) by the pressure receiving area Spri of the primary pulley chamber 2C. In step 11, the target driven pulley pressure Psec (o) to be regulated by the pressure reducing valve 25 is calculated based on the target driven pulley thrust Fsec (o) calculated in step 7 or 9. Specifically, the target drive pulley pressure Psec is calculated by dividing the target drive pulley thrust Fsec by the pressure receiving area Ssec of the secondary pulley chamber 3C.

  Here, the calculation methods used in step 1, step 2 and step 3 are exemplified.

  FIG. 4 is a subroutine illustrating a method for calculating the steady drive pulley thrust Fpri (f) and the steady driven pulley thrust Fsec (f) executed in step 1.

  Referring to FIG. 4, first, at step 11, transmission input torque Ti is calculated based on input torque related information (engine speed and fuel injection time) from engine controller 20. In this embodiment, since power transmission is performed via the lockup torque converter 2, it is preferable to calculate the transmission input torque Ti in consideration of the torque ratio of the torque converter, but the engine output torque is detected. The detected value may be used as it is.

  Next, at step 12, the actual pulley ratio ip is obtained by dividing the primary pulley rotational speed Npri by the secondary pulley rotational speed Nsec. In practice, since the pulley ratio and the gear ratio do not always coincide with each other, when calculating the gear ratio, disturbance compensation or the like must be originally performed on the actual pulley ratio. In the following description, it is assumed that the actual pulley ratio ip obtained by dividing the primary pulley rotational speed Npri by the secondary pulley rotational speed Nsec matches the actual speed ratio i, and the target pulley ratio Ip also matches the target speed ratio I.

  Then, in step 13, using the steady pulley thrust calculation map shown in FIG. 7, based on the transmission input torque Ti calculated in step 11 and the actual pulley ratio ip calculated in step 12, the steady drive pulley thrust Fpri ( f) and the steady driven pulley thrust Fsec (f) are calculated and set as the pulley thrust during steady running where the belt 4 is held without slipping and the current gear ratio i is maintained. In the map of FIG. 7, pulley thrusts that can achieve a desired torque capacity and speed ratio are mapped and stored in advance.

  FIG. 5 is a subroutine illustrating the method for calculating the speed change pulley thrust difference F (v) executed in step 2.

  Referring to FIG. 5, first, at step 21, the target shift speed VI is calculated based on the driving state such as the vehicle speed VSP, the selection range signal, the selection mode signal, and the accelerator pedal stroke amount obtained from the secondary pulley rotation speed Nsec. Next, at step 22, a conversion magnification calculation map shown in FIG. 8 is used, and based on this map, a conversion magnification mg (= Vp / VI) corresponding to the actual pulley ratio ip is obtained. Then, the pulley speed Vp (= mg × VI) is calculated by multiplying the target shift speed VI.

  Then, in step 24, a shift speed pulley thrust difference F (v) is obtained based on the pulley speed Vp calculated in step 23 using the shift speed pulley thrust difference calculation map shown in FIG. In the map of the present embodiment, when the target pulley ratio Ip is large (during downshift), the shift speed pulley thrust difference F (v) is set so that the secondary pulley thrust Fsec is large. When the pulley ratio Ip decreases (during upshift), the shift speed pulley thrust difference F (v) is set so that the primary pulley thrust Fpri increases. Further, in the map of FIG. 9, the side on which the target pulley ratio Ip becomes larger in the pulley speed difference F (v) for the shift speed, that is, the secondary pulley thrust Fsec is used to achieve the target shift speed VI calculated in step 21. It is set to a value obtained by adding a predetermined margin or margin ratio to the necessary pulley speed difference for the shift speed.

  FIG. 6 is a subroutine illustrating the method for calculating the gear ratio feedback pulley thrust difference F (fb) executed in step 3.

  Referring to FIG. 6, first, at step 31, the actual speed ratio i is subtracted from the target speed ratio I to calculate the deviation between the target speed ratio I and the actual speed ratio i, and this deviation is used at step 32. The previous value of the integral deviation of the transmission system is added and updated to a new integral deviation. In step 33, the proportional compensation amount is calculated by multiplying the deviation calculated in step 31 by the proportional gain of the transmission system. Similarly, in step 34, the integral compensation amount is calculated by multiplying the integral deviation calculated in step 32 by the integral gain of the transmission system. In step 35, the proportional ratio compensation amount calculated in step 33 and the integral compensation amount calculated in step 34 are added and added to the primary pulley 2 or the secondary pulley 3, and the gear ratio feedback pulley thrust difference F (fb) is added. Is calculated. In this embodiment, the PI control has been described. However, any control method itself such as PID control may be used as long as it controls feedback control.

  Next, a specific operation of this embodiment will be described with reference to a time chart shown in FIG. In FIG. 10, “steady hydraulic pressure” means the primary pulley pressure Ppri or the secondary pulley pressure Psec calculated based on the steady driving pulley thrust Fpri (f) or the steady driven pulley thrust Fsec (f). The hatched portion indicates the hydraulic pressure calculated based on the shift thrust F (th) = F (v) + F (fb).

  First, when the driver greatly depresses the accelerator pedal at time t1 to request a so-called step-down downshift, the primary pulley pressure Ppri remains the steady oil pressure based on the steady drive pulley thrust Fpri (f), but the secondary pulley pressure Psec is controlled to a hydraulic pressure based on the target driven pulley thrust Fsec (o) obtained by adding the steady driven pulley thrust Fsec (f) and the absolute value | F (th) | . That is, during the time t1 to t2 when the step-down downshift is executed, the shift control by the secondary pulley pressure Psec is executed.

  Further, since the operation of this embodiment is always executed even while traveling, the operation is applied to a shift commanded by the transmission controller 20 in accordance with the travel state such as the vehicle speed VSP in addition to the shift commanded by the driving operation.

  For example, if the transmission controller 19 determines that the shift to the Hi side needs to be corrected at time t2 to t3, the secondary pulley pressure Psec remains at the steady hydraulic pressure based on the steady driven pulley thrust Fsec (f). The primary pulley pressure Ppri is a hydraulic pressure based on the target drive pulley thrust Fpri (o) obtained by adding the steady drive pulley thrust Fpri (f) and the absolute value | F (th) | Controlled. That is, during the period from time t2 to time t3, shift control using the primary pulley pressure Ppri is executed.

  Similarly, when the transmission controller 19 determines that the shift to the Lo side needs to be corrected at time t3 to t4, the primary pulley pressure Ppri remains at the steady hydraulic pressure based on the steady drive pulley thrust Fpri (f). However, the secondary pulley pressure Psec is controlled to a hydraulic pressure based on the target drive pulley thrust Fsec obtained by adding the steady driven pulley thrust Fsec (f) and the absolute value | F (th) | Is done. That is, during the period from time t3 to t4, shift control using the secondary pulley pressure Psec is executed.

  Next, when the driver releases the accelerator pedal at time t4 and requests a so-called foot release upshift, the secondary pulley pressure Psec remains at the steady hydraulic pressure based on the steady driven pulley thrust Fsec (f). The pressure Ppri is controlled to a hydraulic pressure based on the target drive pulley thrust Fpri (o) obtained by adding the steady drive pulley thrust Fpri (f) and the absolute value | F (th) | of the shift thrust. That is, during the time t4 to t5 when the foot release upshift is executed, the shift control using the primary pulley pressure Ppri is executed.

  Therefore, the present invention is required to make the transmission speed pulley thrust difference F (v) required to achieve the target speed V (I) and the actual speed ratio i coincide with the target speed ratio I. Based on the shift thrust F (th) obtained by adding the pulley thrust difference F (fb) for gear ratio feedback, the shift thrust is applied to either the steady drive pulley thrust Fpri or the steady driven pulley thrust Fsec. By adding F (th), the target driving pulley thrust Ppri (o) and the target driven pulley thrust Psec (o) can be calculated independently of each other. Although the target pulley thrust that does not slip is calculated, the target pulley thrust calculated for the other pulley does not become the pulley thrust that slides the belt 4.

  That is, in the present invention, there is no inconvenience of recalculating the target driving pulley thrust Fpri (o) and the target driven pulley thrust Fsec (o), so that the actual driving pulley thrust and the driven pulley thrust change discontinuously. Therefore, the smoothness of the original transmission of the continuously variable transmission is not lost, and the driver does not feel uncomfortable. In addition, the target driving pulley thrust Fpri (o) and the target driven pulley thrust Fsec (o) are recalculated. Can be eliminated.

  Therefore, according to the present invention, it is possible to realize a smooth speed change that does not cause the belt 4 to slip without a complicated process.

  By the way, in this embodiment, the steady drive pulley thrust Fpri (f), the steady driven pulley thrust Fsec (f), the shift speed pulley thrust difference F (v) and the shift feedback pulley thrust F (fb) are independent from each other. Can be calculated. Therefore, in this embodiment, in order to respond to the fuel consumption request from the driver or the transmission controller 20, in step 2, the speed change pulley thrust difference F (v) is limited according to the fuel consumption request command.

  FIG. 11 is a flowchart for calculating the pulley thrust difference F (v) for speed change with a restriction in accordance with the fuel consumption requirement. In the following description, the speed change pulley thrust difference F (v) calculated in step 24 of FIG. 5 is referred to as “speed change pulley thrust difference F (v1)” for the sake of convenience. To do.

  First, in step 41, it is determined whether the shift mode is a manual shift mode in which priority is given to a shift by a driving operation or an automatic shift mode in accordance with a shift command from the transmission controller 20 based on a selection mode signal from the manual shift mode switch 17. The travel mode is selected based on signals relating to various sensors, switches, and transmission input torque input to the machine controller 20. Specifically, based on various information such as vehicle speed VSP, target gear ratio I, accelerator pedal stroke amount, brake signal, selection range signal, engine speed, etc., a step-down downshift running mode and a foot-up upshift running are performed. Various driving modes are conceivable, such as a mode, an auto downshift driving mode based on a shift command from the transmission controller 20, and an auto upshift driving mode.

  In step 42, an application rate rf = rf (m) (0 ≦ rf (m) <1) taking into account fuel efficiency is calculated from the map corresponding to the travel mode selected in step 41. Note that the application rate rf can be set as appropriate according to the shift response required in the travel mode. For example, a travel where a shift response is required, such as a step-down downshift travel mode and a foot lift upshift travel mode. In the mode, the pulley thrust difference F (v) for the shift speed is not limited or kept small, while the shift mode is not required in a travel mode such as the auto downshift travel mode and the auto upshift travel mode. It is preferable that the limit of the speed pulley thrust difference F (v) is increased.

  In step 43, it is determined whether or not the vehicle is in a driving state that requires fuel consumption, based on a fuel consumption request signal from the economy mode switch 19 or a determination by the transmission controller 20.

  First, if there is no fuel consumption request command in step 43, the application rate rf is set to rf (m) = 1 in step 44, and the pulley for shifting speed calculated in step 24 of FIG. Multiply the difference F (v1). In this case, the transmission speed pulley thrust difference F (v) = F (v1) × rf (m) obtained in step 46 is the same as the transmission speed pulley thrust difference F (v1) obtained in FIG. Speed pulley thrust difference F (v1). That is, for calculating the target drive pulley pressure Ppri (o) and the target driven pulley pressure Psec (o), the shift speed pulley thrust difference F (v) = F (v1) that places importance on the shift speed is used as it is.

  On the other hand, if there is a fuel efficiency request command in step 43, the application rate rf is set to the application rate obtained in step 42 (0 ≦ rf (m) <1) in step 45, and in step 46 Multiply the pulley speed difference F (v1) for shifting speed obtained in FIG. In this case, the transmission speed pulley thrust difference F (v) obtained in step 46 is smaller than the transmission speed pulley thrust difference F (v1) obtained in FIG. (v1) × rf (m). That is, in calculating the target drive pulley pressure Ppri (o) and the target driven pulley pressure Psec (o), a pulley speed difference for shift speed F (v) = F (v1) × rf (m) with an emphasis on fuel efficiency is obtained. Use.

  In this embodiment, if there is a fuel efficiency request command, the target driving pulley thrust Fpri and the target driven pulley thrust Fsec are calculated by limiting the pulley speed difference F (v) for shifting speed according to the command. Since it is possible to travel while taking into account fuel efficiency requirements while ensuring the basic performance of achieving the target gear ratio I without causing any slippage, it is possible to improve fuel efficiency.

  Further, in this embodiment, the steady pulley thrusts Fpri (f) and Fsec (f), the target transmission speed pulley thrust difference F (v) and the transmission ratio feedback pulley thrust difference F (fb) are calculated individually. It is easy to limit the pulley thrust difference F (v).

It is the schematic of the V belt type continuously variable transmission which is one form of this invention. FIG. 2 is a system diagram showing a shift control hydraulic circuit and a transmission controller in the same form. 4 is a flowchart illustrating an example of hydraulic control executed by a transmission controller in the same form. 4 is a subroutine illustrating a method for calculating a steady drive pulley thrust and a steady driven pulley thrust executed in step 1 of FIG. 3. 4 is a subroutine illustrating a method for calculating a pulley thrust difference for shift speed, which is executed in Step 2 of FIG. 3. 4 is a subroutine illustrating a method of calculating a gear ratio feedback pulley thrust difference executed in step 3 of FIG. 3. 5 is a steady pulley thrust calculation map used in step 13 of FIG. 4. 6 is a conversion magnification calculation map used in step 22 of FIG. 6 is a pulley speed difference calculation map for shift speed used in step 24 of FIG. 5. It is a time chart which illustrates operation | movement of this form. FIG. 6 is a flowchart for calculating a shift speed pulley thrust difference that is limited in accordance with a fuel efficiency request executed in step 22 of FIG. 5. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 V belt type continuously variable transmission 2 Primary pulley 2a Fixed flange 2b Movable flange 2c Primary pulley chamber 3 Secondary pulley 3a Fixed flange 3b Movable flange 3c Secondary pulley chamber 4 V belt 5 Engine
11 Shift control hydraulic circuit
12 Transmission controller
13 Primary pulley rotation sensor
14 Secondary pulley rotation sensor
16 Accelerator pedal stroke sensor
17 Manual shift switch
17a Inhibitor switch
18 Brake switch
19 Economy mode switch
20 Engine controller
23 Pressure regulator valve
24 Primary pulley pressure reducing valve
25 Secondary pulley side pressure reducing valve

Claims (2)

A driving pulley thrust generating means for generating a target driving pulley thrust for realizing a target speed ratio by passing a belt between the driving pulley and the driven pulley and sandwiching the belt with the driving pulley; and the driven pulley In a belt type continuously variable transmission comprising driven pulley thrust generating means for generating a target driven pulley thrust for sandwiching the belt to achieve a target gear ratio,
A steady drive pulley thrust calculating means for calculating a steady drive pulley thrust required for the drive pulley to hold the belt without slipping and maintain the current gear ratio;
A stationary driven pulley thrust calculating means for calculating a stationary driven pulley thrust required to hold the driven pulley without slipping the belt and maintain a current gear ratio;
A shift speed pulley thrust difference calculating means for calculating a target shift speed pulley thrust difference between the driving pulley thrust and the driven pulley thrust required to achieve the target shift speed;
Gear ratio feedback pulley thrust difference calculating means for calculating a gear ratio feedback pulley thrust difference in the drive pulley or the driven pulley based on the difference between the target gear ratio and the actual gear ratio;
A shift thrust obtained by adding the pulley shift difference for the target shift speed and the pulley thrust difference for the gear ratio feedback is compared with a predetermined value, and when the shift thrust exceeds a predetermined value, the steady drive pulley thrust The absolute value of the shift thrust is added to obtain the target drive pulley thrust and the steady driven pulley thrust is set as the target driven pulley thrust. When the shift thrust is a predetermined value or less, the steady drive pulley thrust is A belt-type continuously variable transmission comprising target pulley thrust calculation means for setting the target driven pulley thrust to be the target driven pulley thrust by adding the steady driven pulley thrust and the absolute value of the shift thrust. .   The speed change pulley thrust difference calculation means is a fuel efficiency command means for instructing that fuel efficiency is required, and a speed change pulley thrust difference limit for limiting the speed change pulley thrust difference in accordance with the fuel efficiency request command. The belt-type continuously variable transmission according to claim 1, further comprising: means.

Images