Device for controlling vehicular belt-type stepless speed change device

Abstract

To provide a device for controlling a vehicular belt-type stepless speed change device to improve acceleration until a maximum speed during race-use, and increase the maximum speed.SOLUTION: An electronic control device 50 comprises: a hydraulic setting part 84 for setting oil pressure to a hydraulic actuator 28c of a secondary pulley 28 by calculating secondary pressure Pout to pinch a transmission belt 30; and a safe rate setting part 86 for setting a safe rate S used to calculate the secondary pressure Pout. The safe rate setting part 86 performs a control to decrease the safe rate S, when a travel mode is a travel mode for a race, an accelerator opening θacc is not less than a predetermined opening θs, an accelerator opening change amount |Δθacc| is not more than a predetermined change amount Δθ, and a vehicle speed V is not less than a predetermined vehicle speed Vs. Thereby, efficiency of power transmission during race-use is improved, i.e., acceleration until a maximum speed is improved and the maximum speed is increased.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for a belt-type continuously variable transmission for a vehicle that aims to improve acceleration up to the maximum speed during race use and increase the maximum speed.

Background Art

[0002] A belt-type continuously variable transmission for a vehicle in which a transmission belt is wound between a primary pulley and a secondary pulley is well known. In the control for setting the belt clamping pressure of the belt-type continuously variable transmission, control is performed to set a set value with a certain safety factor so that the belt does not slip and wear due to disturbances from the road surface or the like. Regarding the control of this belt clamping pressure, Patent Document 1 discloses a technique for performing a traveling road surface determination and reducing the safety factor of the belt clamping pressure when the traveling road surface is a good road with few disturbances, thereby improving the efficiency of power transmission.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the belt-type continuously variable transmission is used in a racing vehicle, improvement in the efficiency of power transmission is prioritized over durability. However, the control for reducing the belt clamping pressure based on the road surface determination disclosed in Patent Document 1 is only performed in a region where the accelerator opening is relatively small. Therefore, there is room for improvement in improving the efficiency of power transmission in a race where the accelerator opening is mostly high, that is, in improving acceleration up to the maximum speed during race use and increasing the maximum speed.

[0005] The present invention has been made against the background of the above circumstances, and an object thereof is to provide a control device for a belt-type continuously variable transmission for a vehicle that improves acceleration up to the maximum speed during race use and increases the maximum speed.

Means for Solving the Problems

[0006] The gist of the present invention is: (a) a control device for a belt-type continuously variable transmission for a vehicle in which a transmission belt is wound between a primary pulley and a secondary pulley, (b) a hydraulic pressure setting unit that calculates a hydraulic pressure command value for clamping the transmission belt and sets the hydraulic pressure to a hydraulic actuator, and a safety factor setting unit that sets a safety factor used for calculating the hydraulic pressure command value, and (c) the safety factor setting unit performs control to lower the safety factor when the driving mode of the vehicle is a race driving mode, the accelerator opening is equal to or greater than a predetermined opening, the change amount of the accelerator opening is equal to or less than a predetermined change amount, and the vehicle speed is equal to or greater than a predetermined vehicle speed.

Effects of the Invention

[0007] According to the present invention, the control device includes a hydraulic pressure setting unit that calculates a hydraulic pressure command value for clamping the transmission belt and sets the hydraulic pressure to a hydraulic actuator, and a safety factor setting unit that sets a safety factor used for calculating the hydraulic pressure command value. The safety factor setting unit performs control to lower the safety factor when the driving mode of the vehicle is a race driving mode, the accelerator opening is equal to or greater than a predetermined opening, the change amount of the accelerator opening is equal to or less than a predetermined change amount, and the vehicle speed is equal to or greater than a predetermined vehicle speed. As a result, the efficiency of power transmission during race use can be improved, that is, the acceleration up to the maximum speed and the increase in the maximum speed can be achieved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Best Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment

[0010] FIG. 1 is a diagram for explaining the schematic configuration of a vehicle 10 to which the present invention is applied, and is also a diagram for explaining the control functions and main parts of the control system for various controls in the vehicle 10. In FIG. 1, the vehicle 10 includes an engine 12 as a power source, a torque converter 14, a forward / reverse switching device 16, a vehicle belt-type continuously variable transmission (hereinafter referred to as a continuously variable transmission) 18, a reduction gear device 20, a differential gear device 22, a pair of left and right front wheels 24L, 24R, and the like.

[0011] The forward / reverse switching device 16 is mainly composed of a forward clutch C1, a reverse brake B1, and a double pinion type planetary gear device 16p.

[0012] The continuously variable transmission 18 includes a primary pulley 26 on the input side with a variable effective diameter as an input side member, a secondary pulley 28 on the output side with a variable effective diameter as an output side member, and a transmission belt 30 wound between the primary pulley 26 and the secondary pulley 28. Power transmission is performed through the friction between the primary pulley 26, the secondary pulley 28, and the transmission belt 30.

[0013] The primary pulley 26 on the input side includes a fixed sheave 26a as a fixed rotating body on the input side, a movable sheave 26b as a movable rotating body on the input side, and a hydraulic actuator 26c for applying an input side thrust for changing the V-groove width between the fixed sheave 26a and the movable sheave 26b. The secondary pulley 28 on the output side includes a fixed sheave 28a as a fixed rotating body on the output side, a movable sheave 28b as a movable rotating body on the output side, and a hydraulic actuator 28c for applying a thrust for changing the V-groove width between the fixed sheave 28a and the movable sheave 28b.

[0014] In the continuously variable transmission 18, the primary pressure Pin supplied to the hydraulic actuator 26c of the primary pulley 26 is controlled by the hydraulic control circuit 40, so that the V-groove widths of the movable sheaves 26b and 28b change, the wrap diameter (effective diameter) of the transmission belt 30 is changed, and the transmission ratio γcvt (= Nin / Nout) of the continuously variable transmission 18 is changed. For example, the primary pressure Pin is controlled so that the output rotational speed Nout, which is the rotational speed of the secondary pulley 28, becomes a predetermined target rotational speed (= Nin / γT) corresponding to the target transmission ratio γT. Further, the secondary pressure Pout supplied to the hydraulic actuator 28c is controlled by the hydraulic control circuit 40, so that the belt clamping pressure W for transmitting power without slippage of the transmission belt 30 is adjusted. The hydraulic control circuit 40 is electrically controlled by an electronic control unit 50 described later.

[0015] The vehicle 10 includes an electronic control unit 50 for executing various controls including the shift control of the continuously variable transmission 18. Various input signals based on detection values detected by various sensors (engine rotational speed sensor 52, turbine rotational speed sensor 54, input rotational speed sensor 56, output rotational speed sensor 58, accelerator opening sensor 60, race driving mode setting switch 62, etc.) provided in the vehicle 10 are input to the electronic control unit 50. For example, various signals representing the engine rotational speed Ne (rpm), turbine rotational speed Nt (rpm), input rotational speed Nin (rpm) of the continuously variable transmission 18, output rotational speed Nout (rpm) of the continuously variable transmission 18 corresponding to the vehicle speed V (km / h), accelerator opening θacc (%), race driving mode setting signal Rmd, etc. are input.

[0016] From the electronic control unit 50, for example, an engine command signal Se for controlling the engine output of the engine 12, a shift control hydraulic pressure command signal Scvt for commanding the control hydraulic pressure of the transmission ratio and belt clamping pressure of the continuously variable transmission 18, a forward and reverse control command signal Sc for controlling the engagement operation of the forward clutch C1 and the reverse brake B1, etc. are output.

[0017] The electronic control unit 50 functionally includes an engine control unit 80, a gear ratio control unit 82, a hydraulic pressure setting unit 84, and a safety factor setting unit 86.

[0018] The engine control unit 80 performs output control of the engine 12. The gear ratio control unit 82 calculates the target gear ratio γT of the continuously variable transmission 18 by applying the accelerator opening θacc and the vehicle speed V to a predetermined gear ratio map, for example.

[0019] The hydraulic pressure setting unit 84 calculates, as hydraulic pressure command values, the primary pressure Pin at which the gear ratio γcvt becomes the target gear ratio γT and the secondary pressure Pout that becomes the belt clamping pressure W for the power transmission belt 30 to transmit power without slipping, respectively. The belt clamping pressure W includes a safety factor S (%) and is calculated by the following formula (1). Belt clamping pressure W = Optimal belt clamping pressure Wa × (1 + S / 100) ··· (1) Here, the optimal belt clamping pressure Wa is the belt clamping pressure required for the power transmission belt 30 to transmit power without slipping, and is obtained in advance by design or experiment from, for example, the target gear ratio γT, the output rotational speed Nout, the required transmission torque, etc. The hydraulic pressure setting unit 84 outputs a transmission control hydraulic pressure command signal Scvt to the hydraulic pressure control circuit 40 so that the calculated primary pressure Pin and secondary pressure Pout are obtained.

[0020] The safety factor setting unit 86 sets the above safety factor S (%) used by the hydraulic pressure setting unit 84 to calculate the secondary pressure Pout. The safety factor setting unit 86, for example, when the running mode of the vehicle is set to the race running mode by the race running mode setting switch 62, the accelerator opening θacc is equal to or greater than a predetermined opening θs, the accelerator opening change amount |Δθacc|, which is the operation change amount of the accelerator opening θacc in a predetermined time, is equal to or less than a predetermined change amount Δθt, and the vehicle speed V is equal to or greater than a predetermined vehicle speed Vs, that is, in the case of high-speed stable running at a high gear ratio, performs control to lower the safety factor S, for example, changes the safety factor S from 25 (%) during normal times to 5 (%). Thereby, the power transmission efficiency is improved, and an improvement in acceleration up to the maximum speed and an increase in the maximum speed can be achieved.

[0021] FIG. 2 is a flowchart for explaining the main part of the control operation of a safety factor setting unit 86 that the electronic control device 50 functionally includes. First, in step S10 (hereinafter, steps are omitted), it is determined whether or not the running mode of the vehicle is set to the race running mode by a race running mode setting signal Rmd from a race running mode setting switch 62. If the determination in S10 is affirmative, in S20, it is determined whether or not an accelerator opening θacc is equal to or greater than a predetermined opening θs set in advance. If the determination in S20 is affirmative, in S30, it is determined whether or not an accelerator opening change amount |Δθacc| is equal to or less than a predetermined change amount Δθt set in advance. If the determination in S30 is affirmative, in S40, it is determined whether or not a vehicle speed V is equal to or greater than a predetermined vehicle speed Vs set in advance. If the determination in S40 is affirmative, in S50, a change to lower the safety factor S (%) of belt clamping is made, and this routine is terminated. Also, when the determinations in S10, S20, S30, and S40 are negative, this routine is also terminated.

[0022] As described above, according to the present embodiment, the electronic control device 50 includes a hydraulic pressure setting unit 84 that calculates a secondary pressure Pout for belt clamping of the transmission belt 30 and sets the hydraulic pressure to a hydraulic actuator 28c of the secondary pulley 28, and a safety factor setting unit 86 that sets a safety factor S used for calculating the secondary pressure Pout. The safety factor setting unit 86 performs control to lower the safety factor S when the running mode of the vehicle is the race running mode, the accelerator opening θacc is equal to or greater than the predetermined opening θs, the accelerator opening change amount |Δθacc| is equal to or less than the predetermined change amount Δθt, and the vehicle speed V is equal to or greater than the predetermined vehicle speed Vs. Thereby, the efficiency of power transmission during race use is improved, that is, the acceleration up to the maximum speed and the increase in the maximum speed are achieved.

[0023] Note that the above description is merely one embodiment, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

Explanation of Reference Numerals

[0024] 18: Continuously variable transmission (belt type continuously variable transmission for vehicles) 26: Primary pulley 28: Secondary pulley 28c: Hydraulic actuator 30: Transmission belt 50: Electronic control unit (control unit) 84: Hydraulic pressure setting unit 86: Safety factor setting unit Pout: Secondary pressure (hydraulic pressure command value) S: Safety factor θacc: Accelerator opening θs: Predetermined opening |Δθacc|: Accelerator opening change amount Δθt: Predetermined change amount V: Vehicle speed Vs: Predetermined vehicle speed

Claims

【Claim 1】 A control device for a belt-type continuously variable transmission for a vehicle in which a transmission belt is wound between a primary pulley and a secondary pulley, comprising a hydraulic pressure setting unit that calculates a hydraulic pressure command value for clamping the transmission belt and sets the hydraulic pressure to a hydraulic actuator, and a safety factor setting unit that sets a safety factor used for calculating the hydraulic pressure command value, wherein the safety factor setting unit performs control to lower the safety factor when the driving mode of the vehicle is a racing driving mode, the accelerator opening is equal to or greater than a predetermined opening, the change amount of the accelerator opening is equal to or less than a predetermined change amount, and the vehicle speed is equal to or greater than a predetermined vehicle speed. A control device for a belt-type continuously variable transmission for a vehicle.

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