JP6130781B2 - Control device for continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission, and more specifically to a control device that performs shift control of a continuously variable transmission mounted on a vehicle.

  Conventionally, a control device that performs shift control of a continuously variable transmission mounted on a vehicle has been proposed, and in particular, control that performs shift control when elongation occurs in the circumference of a power transmission element of a continuously variable transmission. An apparatus has been proposed (for example, Patent Document 1).

  In the technique described in Patent Document 1, the response delay of the transmission ratio feedback control is eliminated by limiting the transmission ratio feedback control when the power transmission element is elastically deformed.

JP 2012-149659 A

  By the way, in the technique described in Patent Document 1, it is noted that the target speed ratio may not be achieved when the circumference of the power transmission element is extended by elastic deformation. We propose to limit the control. However, no consideration is given to the case where the power transmission element is deformed due to deterioration over time.

  When the peripheral length of the power transmission element is extended due to deterioration with time, the gear ratio changes to the LOW side, so that the torque input to a drive member such as a differential mechanism after the transmission increases unintentionally. As a result, the load applied to the driving member also increases, and the durability may be reduced.

  The object of the present invention is to solve the above-described problems, and to increase the torque input to a drive member such as a differential mechanism after the transmission even when the power transmission element of the continuously variable transmission is deformed due to deterioration with time. An object of the present invention is to provide a control device for a continuously variable transmission which is prevented.

In order to solve the above-described problem, in claim 1, an input side element connected to a power source mounted on a vehicle, an output side element connected to a drive wheel of the vehicle, and the power source A continuously variable transmission having a power transmission element for transmitting the power of the input side element from the input side element to the output side element, a regulating member for regulating a spread width of the input side element, and the input side element for the power transmission element And a control means for controlling the input side element and the output side element with the calculated clamping pressure. A gear ratio detecting means for detecting a gear ratio of the machine, a gear ratio determining means for judging whether the detected gear ratio is larger than a preset maximum gear ratio of the continuously variable transmission , The driving force required by the driver is less than the predetermined value. Or a whether determining driving force determining means, the control means, the required driving force is determined to be equal to or greater than a predetermined value, and the continuously variable which the detected gear ratio is set in advance When it is determined that the transmission is greater than the maximum transmission ratio, the input torque input to the continuously variable transmission is reduced.

According to a second aspect of the present invention, the control means includes vehicle speed detection means for detecting a vehicle speed of the vehicle, and an input torque input to the continuously variable transmission when the detected vehicle speed exceeds a predetermined speed. The reduction is reduced.

According to a third aspect of the present invention, the control means is configured to reduce the input torque input to the continuously variable transmission based on the ratio between the detected gear ratio and the maximum gear ratio.

In Claim 4 , it was comprised so that the said power transmission element might be a chain.

According to the first aspect of the present invention, in the continuously variable transmission control device, the gear ratio of the continuously variable transmission is detected, and whether the detected gear ratio is larger than a preset maximum gear ratio of the continuously variable transmission. And determining whether or not the driving force required by the driver of the vehicle is equal to or greater than a predetermined value, determining that the required driving force is equal to or greater than a predetermined value, and detecting the detected gear ratio in advance. Since it is configured to reduce the input torque input to the continuously variable transmission when it is determined that it is greater than the set maximum transmission ratio of the continuously variable transmission, the circumference of the power transmission element has increased due to deterioration over time. Even in this case, it is possible to prevent a torque exceeding an allowable value from being input to a driving member such as a differential mechanism, and thus it is possible to improve the durability of these driving members.

In this case, when the required driving force is determined to be equal to or larger than a predetermined value, and then, is reduced input torque input to the continuously variable transmission, unnecessarily executing the reduction control of the input torque This can prevent the processing from becoming complicated. That is, the gear ratio is greatly changed to the LOW side when a large driving force is required, more specifically, when the driver greatly depresses the accelerator pedal at the start of the vehicle. The input torque reduction control is configured to be limited to a case where a driving force of a predetermined value or more is requested by the driver, and the unnecessary reduction of the input torque input to the continuously variable transmission is avoided. .

In the continuously variable transmission control device according to claim 2 , the vehicle speed of the vehicle is detected, and when the detected vehicle speed exceeds a predetermined speed, the reduction of the input torque input to the continuously variable transmission is stopped. In addition to the effects described above, it is possible to more effectively avoid unnecessary execution of the input torque reduction control and prevent the processing from becoming complicated. That is, when the vehicle speed exceeds a predetermined speed, the gear ratio is reduced and torque exceeding the allowable value is not applied to the drive members after the transmission. Therefore, in such a case, control for reducing the input torque is not performed. I made it.

In the continuously variable transmission control device according to claim 3 , because the input torque input to the continuously variable transmission is reduced based on the ratio between the detected gear ratio and the maximum gear ratio, In addition to the above-described effects, it is possible to more appropriately control the reduction of the input torque input to the continuously variable transmission, thereby further improving the durability of the drive member.

In the control device for continuously variable transmission according to claim 4 , since the power transmission element is a chain, in addition to the above-described effects, the durability of the drive member after the continuously variable transmission is further increased. Can be improved. In other words, some power transmission elements of continuously variable transmissions use metal belts, etc., but chains are more likely to stretch due to elastic deformation than metal belts, etc., compared to belt type continuously variable transmissions and the like. Since the amount of deformation due to deterioration with time is large, it is possible to further improve the durability of the drive member by limiting the input torque input to the continuously variable transmission when the circumference of the chain extends due to deterioration with time. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an overall control device for a continuously variable transmission according to an embodiment of the present invention. It is explanatory drawing which shows the structure of the power transmission element of the continuously variable transmission shown in FIG. It is explanatory drawing which shows the deformation of the power transmission element shown in FIG. 1, and the change of a gear ratio. It is explanatory drawing for demonstrating the control member provided in the continuously variable transmission shown in FIG. 1, and its effect. It is a flowchart which shows operation | movement of the apparatus shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment for implementing a continuously variable transmission control device according to the invention will be described with reference to the accompanying drawings.

  In FIG. 1, the code | symbol 10 shows an engine (internal combustion engine. Power source). The engine 10 is mounted on a vehicle 14 provided with drive wheels 12 (the vehicle 14 is partially indicated by the drive wheels 12 and the like).

  The throttle valve 16 disposed in the intake system of the engine 10 is disconnected from the accelerator pedal 18 disposed on the floor surface of the vehicle driver's seat and the DBW (Drive By Wire) mechanism 20 including an actuator such as an electric motor is disconnected. And is opened and closed by the DBW mechanism 20.

  The intake air metered by the throttle valve 16 flows through an intake manifold (not shown) and mixes with fuel injected from an injector (not shown) in the vicinity of the intake port of each cylinder to form an air-fuel mixture. When an intake valve (not shown) is opened, it flows into a combustion chamber (not shown) of the cylinder. The air-fuel mixture is ignited and combusted in the combustion chamber, and after driving the piston and rotating the crankshaft (not shown), it is discharged to the outside of the engine 10 as exhaust.

  The rotation of the crankshaft is input to the automatic transmission T via the output shaft 22 and the torque converter 24. The automatic transmission T includes a continuously variable transmission (hereinafter referred to as “CVT”) 26.

  The CVT 26 is a main shaft MS, more precisely, a drive pulley (DR pulley, input side element) 26a disposed on the outer peripheral side shaft, and a counter shaft (output shaft) CS parallel to the main shaft MS, more precisely its It consists of a driven pulley (DN pulley; output side element) 26b disposed on the outer peripheral side shaft and a power transmission element, for example, a metal chain 26c, hung between them.

  FIG. 2 is an explanatory view showing the power transmission element of the CVT 26 according to the embodiment of the present invention, more specifically, the structure of the chain 26c. As shown in FIG. 2, the chain 26c includes a plurality of link plates 26c1 and rocker pins 26c3 for flexibly connecting the plurality of link plates 26c1 to each other via pin holes 26c2 formed in the link plate 26c1. Composed.

  Both end portions of the rocker pin 26c3 of the chain 26c are formed so that the end portions protrude from the side of the chain 26c, and the end surfaces of the protruded rocker pin 26c3 and the inner surfaces of the DR pulley 26a and the DN pulley 26b come into contact with each other. Power is transmitted by the frictional force generated by this.

  Returning to FIG. 1, the description will be continued. The DR pulley 26a is fixed to the stationary pulley half 26a1 that is not rotatable relative to the outer shaft of the main shaft MS and is not movable in the axial direction, and to the outer shaft of the main shaft MS. A movable pulley half 26a2 that is relatively incapable of relative rotation and movable relative to the fixed pulley half 26a1 in the axial direction, and is provided on the side of the movable pulley half 26a2 and is supplied with hydraulic pressure (pressure of hydraulic oil) Is provided with a hydraulic actuator 26a3 composed of a piston, a cylinder and a spring for pressing the movable pulley half 26a2 toward the fixed pulley half 26a1.

  The DN pulley 26b has a fixed pulley half 26b1 that is not rotatable relative to the outer peripheral shaft of the countershaft CS and is not axially movable, and an axial direction relative to the fixed pulley half 26b1 that is not rotatable relative to the countershaft CS. A movable pulley half 26b2 which is relatively movable to the movable pulley half 26b2, and is provided on the side of the movable pulley half 26b2 so that the movable pulley half 26b2 is directed to the fixed pulley half 26b1 when hydraulic pressure (hydraulic oil pressure) is supplied. And a hydraulic actuator 26b3 composed of a piston, a cylinder and a spring.

  Although not shown in FIG. 1, a stopper (a regulating member, which will be described later) for regulating the maximum spreading width of each pulley is provided outside the movable pulley halves 26a2 and 26b2 of the DR / DN pulleys 26a and 26b. Provided.

  In the automatic transmission T, the CVT 26 is connected to the engine 10 via the forward / reverse switching mechanism 28. The forward / reverse switching mechanism 28 includes a forward clutch 28a that allows the vehicle 14 to travel in the forward direction, a reverse brake clutch 28b that allows the vehicle 14 to travel in the reverse direction, and a planetary gear mechanism 28c disposed therebetween. The CVT 26 is connected to the engine 10 via a forward clutch 28a (and a reverse brake clutch 28b).

  The rotation of the countershaft CS is transmitted from the secondary shaft (intermediate shaft) SS to the drive wheels 12 via a gear. That is, the rotation of the counter shaft CS is transmitted to the secondary shaft SS through the gears 30a and 30b, and the rotation is transmitted from the differential mechanism 32 to the left and right drive wheels (only the right side is shown) 12 through the gear 30c.

  A disc brake 34 is disposed in the vicinity of the driving wheel (front wheel) 12 and a driven wheel (rear wheel, not shown), and a brake pedal 36 is disposed on the vehicle driver's seat floor. The brake pedal 36 is connected to the disc brake 34 via a master back 38 and a master cylinder 40.

  When the driver depresses the brake pedal 36, the depressing force is increased by the master back 38 and transmitted from the master cylinder 40 to the disc brake 34, and the disc brake 34 is operated to brake (decelerate) the vehicle 14.

  In the forward / reverse switching mechanism 28, the forward clutch 28a and the reverse brake clutch 28b are switched by the driver operating a range selector 44 provided in the vehicle driver's seat to select one of the ranges such as P, R, N, and D. It is done by selecting. The range selection by the driver's operation of the range selector 44 is transmitted to the manual valve of the transmission hydraulic pressure supply mechanism 46, and the vehicle 14 travels forward or backward.

  Although not shown, the transmission hydraulic pressure supply mechanism 46 is provided with an oil pump (oil feed pump), which is driven by the engine 10 to pump up the hydraulic oil stored in the reservoir and discharge it to the oil passage.

  The oil passages are the piston chambers of the hydraulic actuators 26a3 and 26b3 of the DR / DN pulleys 26a and 26b of the CVT 26, the piston chambers of the forward / reverse brake clutches 28a and 28b of the forward / reverse switching mechanism 28, and the pistons of the lock-up clutch of the torque converter 24. The chamber is connected via a solenoid valve.

  In this specification, the automatic transmission T includes a torque converter 24, a CVT 26, and a forward / reverse switching mechanism 28 (more specifically, its forward clutch 28a (or reverse brake clutch 28b)).

  A crank angle sensor 50 is provided at an appropriate position such as near the cam shaft (not shown) of the engine 10 and outputs a signal indicating the engine speed NE for each predetermined crank angle position of the piston. In the intake system, an absolute pressure sensor 52 is provided at an appropriate position downstream of the throttle valve 16 and outputs a signal proportional to the intake pipe absolute pressure (engine load) PBA.

  The actuator of the DBW mechanism 20 is provided with a throttle opening sensor 54 and outputs a signal proportional to the opening TH of the throttle valve 16 through the rotation amount of the actuator.

  An accelerator opening sensor 56 is provided in the vicinity of the accelerator pedal 18 and outputs a signal proportional to the accelerator opening AP corresponding to the driver's accelerator pedal operation amount. A brake switch 58 is provided in the vicinity of the brake pedal 36, and outputs an ON signal when the brake pedal 36 is operated by the driver. The output of the crank angle sensor 50 and the like described above is sent to the engine controller 66.

  The main shaft MS is provided with an NT sensor (rotational speed sensor) 70, which outputs a pulse signal indicating the rotational speed NT of the main shaft MS, specifically, the input shaft rotational speed of the forward clutch 28a.

  An NDR sensor (rotational speed sensor) 72 is provided at an appropriate position in the vicinity of the DR pulley 26a of the CVT 26 to output a pulse signal corresponding to the rotational speed NDR of the DR pulley 26a, in other words, the output shaft rotational speed of the forward clutch 28a. To do.

  An NDN sensor (rotational speed sensor) 74 is provided at an appropriate position in the vicinity of the DN pulley 26b of the CVT 26 to output a pulse signal indicating the rotational speed NDN of the DN pulley 26b (the rotational speed of the countershaft CS), and the secondary shaft. A V sensor (rotation number sensor, vehicle stop detection means, vehicle speed detection means) 76 is provided in the vicinity of the SS gear 30b, and a pulse signal indicating the vehicle speed V, which represents the traveling speed of the vehicle 14 through the rotation of the secondary shaft SS, is provided. Output.

  A range selector switch 80 is provided in the vicinity of the above-described range selector 44 and outputs a signal corresponding to a range such as P, R, N, D selected by the driver.

  In the transmission hydraulic pressure supply mechanism 46, a hydraulic pressure sensor 82 is disposed in the oil passage leading to the DN pulley 26b of the CVT 26, and a signal corresponding to the hydraulic pressure supplied to the piston chamber (not shown) of the hydraulic actuator 26b3 of the DN pulley 26b. Is output. Although not shown, hydraulic sensors are also arranged in oil passages connected to the piston chamber of the forward clutch 28a and the piston chamber of the lock-up clutch of the torque converter 24, and output a signal corresponding to each supply hydraulic pressure.

  The output of the NT sensor 70 and the like described above is sent to the shift controller 90 (control means) including the outputs of other sensors (not shown). The engine controller 66 and the shift controller 90 include a microcomputer including a CPU, a ROM, a RAM, an I / O, and the like, and are configured to be able to communicate with each other.

  The engine controller 66 determines the target throttle opening based on the sensor output described above to control the operation of the DBW mechanism 20, determines the fuel injection amount and the ignition timing, and controls the operation of an ignition device such as an injector or a spark plug. To do.

  The shift controller 90 calculates the pulley supply hydraulic pressure (clamping pressure) based on the sensor output described above, and excites and demagnetizes various solenoid valves of the transmission hydraulic pressure supply mechanism 46 according to the calculated clamping pressure, thereby DR / DN. The hydraulic actuators 26a3 and 26b3 of the pulleys 26a and 26b are controlled to supply and discharge hydraulic pressure to the piston chamber to control the operation of the CVT 26, and the operations of the forward / reverse switching mechanism 28 and the torque converter 24 are controlled.

  More specifically, the shift controller 90 calculates the target gear ratio of the CVT 26 calculated based on the detected vehicle speed V and the accelerator pedal opening AP, and the input torque input from the engine 10 to the CVT 26 via the torque converter 24. Based on the above, the clamping pressure of the DR / DN pulleys 26a and 26b is calculated, and the operation of the CVT 26 is controlled. In this specification, the shift control by the shift controller 90 is referred to as “normal control”.

  FIG. 3 shows the amount of deformation of the power transmission element, more specifically, when the chain 26c is used as the power transmission element, the change in the circumferential length of the chain 26c measured after a predetermined durability test and the LOW end gear ratio. FIG. 4 is an explanatory view showing a change, and FIG. 4 is an explanatory view for explaining a stopper (regulating member) 94 provided on the CVT 26 and its effect.

  As is apparent from the structure of the chain 26c shown in FIG. 2, when power is transmitted from the DR pulley 26a to the DN pulley 26b via the chain 26c, the contact portion between the link plate 26c1 and the rocker pin 26c3 by continuous use, that is, The inner peripheral surface of the pin hole 26c2 is worn. As a result, the pin hole 26c2 extends in the circumferential direction (chain longitudinal direction) and the interval between the rocker pins 26c3 also increases, so that the entire chain 26c extends in the circumferential direction.

  On the other hand, as shown in FIG. 4, in the embodiment of the present invention, a stopper that regulates the axial width of the DR pulley 26a outside the movable pulley half 26a2 of the DR pulley 26a that is relatively movable in the axial direction. 94a is provided. Similarly, a stopper 94b is provided on the outside of the movable pulley half 26b2 of the DN pulley 26b to mechanically fix (restrict) the axial width of the DN pulley 26b.

  That is, when the gear ratio is set to the LOW side, more precisely, to the LOW end, such as when the vehicle 14 starts, the position of the DR pulley 26a is mechanically fixed by the stopper 94. For this reason, even when the circumferential length of the chain 26c is extended due to deterioration with time and the input torque increases when the vehicle starts, the DN pulley 26b side is affected by the circumferential length change of the chain 26c and the winding radius is increased. However, the DR pulley 26a side is hardly affected.

  Therefore, as shown in FIG. 3, when the chain 26c is used as a power transmission element, the LOW end gear ratio increases in proportion to the increase in the circumferential length of the chain 26c due to deterioration over time.

  Although not shown in FIG. 3, even when a metal belt is used as a power transmission element, a phenomenon in which the peripheral length increases due to deterioration with time occurs. However, in the case of a metal belt, power is transmitted by the pressing force of the belt, so the amount of change in the circumferential direction is small compared to the chain 26c, and the change in gear ratio is also small. The influence of torque increase is also relatively small.

  FIG. 5 is a flowchart showing the operation of the control device for the chain type continuously variable transmission according to this embodiment, more specifically, the processing performed by the shift controller 90. Note that the process of FIG. 5 is repeatedly executed at predetermined time intervals.

  In the following, in S10 (S: processing step), it is determined whether or not the vehicle speed V of the vehicle 14 detected by the V sensor 76 is equal to or lower than a predetermined speed (for example, 30 km / h). Immediately after the vehicle 14 has started, the value of the vehicle speed V is low, so S10 is usually affirmed in the first determination and the process proceeds to S12.

  In S12, it is determined whether or not the accelerator opening AP detected by the accelerator opening sensor 56 is greater than or equal to a predetermined opening (for example, 4/8 or more). When the accelerator pedal opening AP is small, that is, when the driving force requested by the driver is relatively small, there is no possibility that an input torque exceeding the allowable value of the driving member is applied, and it can be determined that the durability is not affected. When the result in S12 is negative, the program proceeds to S14 and the above-described normal control is performed.

  On the other hand, when the vehicle speed V is low and the accelerator pedal opening AP is large, in other words, when the gear ratio is set to the LOW side and a relatively large driving force is required, the circumference of the chain 26c When the length is extended due to deterioration over time, there is a possibility that torque exceeding the allowable value is applied to a drive member (gear 30a, 30b, 30c, counter shaft CS, secondary shaft SS, etc.) such as the differential mechanism 32. Therefore, in this embodiment, the input torque reduction control (described later) is executed only when the determination in S10 and S12 is affirmative.

  Accordingly, when the result in S12 is affirmative, the program proceeds to S16 and the gear ratio i is detected (calculated). Specifically, the speed ratio i is calculated by dividing the rotational speed NDN of the DN pulley 26b detected by the NDN sensor 74 by the rotational speed NDR of the DR pulley 26a detected by the NDR sensor 72.

  The gear ratio i is calculated every time the process of S16 is performed from when the vehicle 14 starts traveling, and the calculation result is stored in the memory of the shift controller 90. Therefore, the determination in S16 may be performed based on the average value per predetermined time, or may be performed based on the instantaneous value when the processing in S16 is executed.

  Next, in S18, the value obtained by dividing the detected speed ratio i by the designed maximum speed ratio iLIMIT is 1.0 or more, in other words, whether the detected speed ratio i exceeds the maximum speed ratio iLIMIT. It is judged whether or not.

  Normally, the gear ratio i does not exceed the maximum gear ratio iLIMIT, but when the circumference of the chain 26c is extended due to deterioration over time, the gear ratio is set when the gear ratio is set to the LOW end as when the vehicle 14 starts. A situation occurs in which i exceeds the maximum gear ratio iLIMIT. Accordingly, the determination in S18 corresponds to determining whether or not the circumferential length of the chain 26c has increased due to deterioration over time.

  When the result in S18 is negative, there is no need to execute input torque reduction control, which will be described later, the process proceeds to S14 and normal control is executed. On the other hand, when the result in S18 is affirmative and it is determined that the circumferential length of the chain 26c is extended, the process proceeds to S20, and input torque reduction control for reducing the input torque input from the engine 10 to the CVT 26 is executed.

  Specifically, based on the ratio (i / iLIMIT) between the gear ratio i and the maximum gear ratio iLIMIT, that is, the engine 10 set in advance at the time of shipment of the vehicle 14 by an amount proportional to the amount of change in the gear ratio. The maximum output Tmax is reduced and the program is terminated.

  Note that the reduction of the input torque input from the engine 10 to the CVT 26 is achieved by stopping the fuel supply, stopping the ignition, retarding the ignition timing, changing the throttle opening, or a combination thereof.

  When a torque converter 24, a speed reduction mechanism (not shown) or the like is interposed between the engine 10 and the CVT 26, the process of S20 is performed after converting the increase in engine output torque by the torque converter 24 or the like. Needless to say.

  Further, when the result of S10 is negative in the next and subsequent loops, that is, when the vehicle 14 starts and the vehicle speed V exceeds the predetermined speed, the gear ratio is changed from the LOW end to the HIGH side, and the drive member is allowed. Since it can be determined that there is no possibility that an input torque exceeding the value is applied, the process proceeds to S14, where the above-described input torque reduction control is stopped and normal control is executed.

As described above, according to the embodiment of the present invention, the DR pulley (input side element) 26 a connected to the engine (internal combustion engine; power source) 10 mounted on the vehicle 14, and the drive wheel 12 of the vehicle 14. A CVT (continuously variable) having a DN pulley (output-side element) 26b connected to the power source and a power transmission element (chain 26c, metal belt) for transmitting the power of the engine 10 from the DR pulley 26a to the DN pulley 26b. (Transmission) 26, a stopper (regulating member) 94a for regulating the spread width of the DR pulley 26a, and a clamping pressure of the DR pulley 26a and the DN pulley 26b with respect to the power transmission element are calculated, and the calculated clamping pressure In the control device for the continuously variable transmission, the control means (shift controller 90) for controlling the DR pulley 26a and the DN pulley 26b is provided. , A gear ratio detecting means (shift controller 90, S16) for detecting the gear ratio i of the CVT 26, and determining whether the detected gear ratio i is larger than a preset maximum gear ratio iLIMIT of the CVT 28. Gear ratio determination means (shift controller 90, S18) and driving force determination means (shift controller 90, S12) for determining whether or not the driving force requested by the driver of the vehicle 14 is a predetermined value or more , When it is determined that the required driving force is greater than or equal to a predetermined value and the detected gear ratio i is greater than the preset maximum gear ratio iLIMIT of the CVT 26, the control means Since the input torque input to the CVT 26 is configured to be reduced, even if the circumference of the power transmission element is extended due to deterioration over time, Torque exceeding the capacity can be prevented from being applied to driving members (gears 30a, 30b, 30c, counter shaft CS, secondary shaft SS, etc.) such as differential mechanism 32, and thus the durability of these driving members can be improved. Is possible.

Further, avoids unnecessarily executing the reduction control of the input torque, the processing can be prevented from being complicated. That is, the gear ratio i greatly changes to the LOW side only when a large driving force is required, more specifically, when the driver greatly depresses the accelerator pedal 18 when the vehicle 14 starts. Therefore, the input torque reduction control is configured to be limited to a case where a driving force of a predetermined value or more is requested by the driver, and the input torque input to the CVT 26 is prevented from being unnecessarily reduced. since the, and avoids unnecessarily executing the reduction control of the input torque, the processing can be prevented from being complicated.

  The control means includes vehicle speed detecting means (V sensor 76) for detecting the vehicle speed V of the vehicle 14, and when the detected vehicle speed V exceeds a predetermined speed, an input torque input to the CVT 26 is detected. Since the reduction is stopped, in addition to the above-described effect, it is possible to more effectively avoid unnecessary execution of the input torque reduction control, and to prevent the processing from becoming complicated. That is, when the vehicle speed V exceeds a predetermined speed, the speed ratio i becomes small, and torque exceeding the allowable value is not applied to the drive member after the CVT 26. In such a case, input torque reduction control is not performed. I did it.

  Further, since the control means is configured to reduce the input torque input to the CVT 26 based on the ratio of the detected gear ratio i and the maximum gear ratio iLIMIT, in addition to the above effects, It is possible to more appropriately control the reduction of the input torque that is input, and thus the durability of the drive member can be further improved.

  Further, since the power transmission element is configured to be the chain 26c, in addition to the above-described effects, the durability of the drive member after the CVT 26 can be further improved. In other words, the power transmission element of the CVT 26 uses a metal belt or the like, but the chain 26c is more likely to be stretched due to elastic deformation than the metal belt or the like, and the amount of deformation due to deterioration with time is less than that of the belt type CVT. Therefore, the durability of the drive member can be further improved by limiting the input torque input to the CVT 26c when the circumferential length of the chain 26c is extended due to deterioration over time.

  In the above description, the chain 26c is mainly used as the power transmission element of the CVT 26. However, the gist of the present invention is applicable to the control of the CVT 26 that employs a belt as the power transmission element.

  10 engine (internal combustion engine, power source), 14 vehicle, 26 CVT (continuously variable transmission), 26a DR pulley (input side element), 26b DN pulley (output side element), 26c chain (power transmission element), 76 V Sensor (vehicle speed detection means), 90 shift controller (control means, transmission ratio detection means, transmission ratio determination means, driving force determination means), 94 stopper

Claims (4)

An input side element connected to a power source mounted on a vehicle, an output side element connected to a drive wheel of the vehicle, and a power transmission for transmitting power of the power source from the input side element to the output side element A continuously variable transmission having an element; a regulating member that regulates a spread width of the input side element; and a clamping pressure between the input side element and the output side element with respect to the power transmission element. In a control device for a continuously variable transmission comprising control means for controlling the input side element and the output side element with pressure, a speed ratio detecting means for detecting a speed ratio of the continuously variable transmission, and the detected Gear ratio determining means for determining whether or not a gear ratio is greater than a preset maximum gear ratio of the continuously variable transmission; and determining whether or not the driving force requested by the driver of the vehicle is greater than or equal to a predetermined value. and a driving force determining means, the control hand , The required driving force is determined to be equal to or greater than a predetermined value, and when the detected gear ratio is determined to be larger than the preset said continuously variable transmission maximum speed ratio of the Mu A control device for a continuously variable transmission, wherein the input torque input to the step transmission is reduced.   The control means includes vehicle speed detection means for detecting the vehicle speed of the vehicle, and stops reducing the input torque input to the continuously variable transmission when the detected vehicle speed exceeds a predetermined speed. The continuously variable transmission control device according to claim 1.   3. The continuously variable transmission according to claim 1, wherein the control unit limits an input torque input to the continuously variable transmission based on a ratio between the detected transmission gear ratio and the maximum transmission gear ratio. Transmission control device.   The continuously variable transmission control device according to any one of claims 1 to 3, wherein the power transmission element is a chain.

Images