JP2001146960A - Shift control device of hydraulic continuously variable transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shift control device of hydraulic continuously variable transmission for vehicle capable of controlling the gear ratio certainly to its target value while the primary pressure is well secured at the time of the vehicle being stopped substantially. SOLUTION: At normal times, the target revolving speed of a rotary element is set by a revolving speed feedback control means 54 using the speed of a vehicle and the load on an engine mounted thereon and a feedback control is made for the hydraulic controlling system 64 of the rotary element 21 so that the actual revolving speed becomes identical to the target value, and when the vehicle is stopped substantially, changing-over is made from the revolving speed feedback control to a pressure feedback control made by a pressure feedback control means 55, and the actual oil pressure of the hydraulic controlling system 64 is sensed by an oil pressure sensing means 47, and the target oil pressure of the system 64 is set by a target oil pressure setting means 55A and thereupon the system 64 is feedback controlled so that the actual oil pressure becomes identical to its target oil pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a hydraulic type continuously variable transmission for a vehicle, which controls a speed ratio by rotational speed feedback control or pressure feedback control.

[0002]

2. Description of the Related Art In recent years, continuously variable transmissions have been focused on the point that they can avoid a shift shock by continuously controlling the gear ratio and that they have excellent fuel consumption efficiency. Have been. In such a continuously variable transmission, the gear ratio is generally controlled by hydraulic control.

For example, in the case of a belt-type continuously variable transmission, power generated by an engine is transmitted from a primary pulley to a secondary pulley via a belt. On this occasion,
Normally, hydraulic pressure (line pressure) set for the hydraulic piston of the secondary pulley according to basic characteristics such as transmission torque
To provide a clamping force to the belt and adjust the hydraulic pressure (primary pressure) applied to the hydraulic piston of the primary pulley to change the gear ratio (the gear ratio (effective radius ratio between the primary pulley and the secondary pulley) Control].

In the case of a continuously variable transmission for a vehicle, such a shift control is generally performed by a rotation speed (rotation speed) feedback control of a primary pulley. That is, in the shift control, the target rotation speed of the primary pulley is set based on the vehicle speed and the throttle opening, and the hydraulic pressure applied to the primary pulley is controlled so that the actual rotation speed of the primary pulley becomes the target rotation speed. It is done by doing.

By the way, it is general that the rotation speed sensor becomes difficult to detect as the rotation speed becomes lower. Therefore, when the vehicle is traveling at extremely low speed or stopped, it is difficult to detect the rotation speed of the primary pulley. Therefore, the rotation speed feedback control cannot be executed, and the gear ratio is set to full low (minimum) by open loop control. (Speed ratio on the high speed side).

[0006]

However, open loop control has the following problems due to poor control accuracy. If the primary pressure is too high, the vehicle gradually shifts up when traveling on a congested road, which causes a deterioration in startability.

[0007] If the primary pressure is too low, the input torque cannot be fully transmitted at the time of restart immediately after sudden braking or the like where the speed ratio may become an intermediate speed ratio, and belt slip may occur. In addition, there is a problem that the responsiveness when the vehicle speed increases after starting and the vehicle shifts up is deteriorated. The present invention has been made in view of the above-described problems, and has been made to ensure that the gear ratio can be reliably controlled to a target value (for example, full low) while securing the primary pressure when the vehicle is traveling at extremely low speed or when the vehicle is stopped. It is an object of the present invention to provide a shift control device for a hydraulic continuously variable transmission for a vehicle.

[0008]

For this reason, in the shift control apparatus for a vehicle hydraulic continuously variable transmission according to the present invention, the speed of the vehicle and the engine mounted on the vehicle are normally controlled by the rotation speed feedback control means. The target rotational speed of the rotary element is set based on the load of the vehicle, and the hydraulic control system of the rotary element is feedback-controlled so that the actual rotational speed becomes the target rotational speed. Is detected by the switching means, the control of the hydraulic control system of the rotating element is switched from the rotational speed feedback control to the pressure feedback control by the pressure feedback control means. At the time of pressure feedback control, the actual hydraulic pressure of the hydraulic control system is detected by the hydraulic pressure detection means, the target hydraulic pressure of the hydraulic control system is set by the target hydraulic pressure setting means, and the target pressure is detected by the hydraulic pressure detection means by the pressure feedback control means. The hydraulic control system of the rotary element is feedback-controlled so that the actual hydraulic pressure becomes the target hydraulic pressure set by the target hydraulic pressure setting means.
Therefore, even when the vehicle is traveling at extremely low speed or stopped,
It is possible to reliably control the gear ratio to a target value (for example, full low) while securing the hydraulic pressure at an optimum value.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a shift control device of a hydraulic continuously variable transmission for a vehicle as an embodiment of the present invention. The description will be made based on these drawings. First,
The power transmission mechanism of the vehicle according to the present embodiment will be described. As shown in FIGS. 2A and 2B, in this power transmission mechanism, rotation output from an engine (internal combustion engine) 1 is converted by a torque converter ( The torque is transmitted to a belt-type continuously variable transmission (CVT) 20 via a torque converter 2 and further transmitted to a front differential 31.

A forward / reverse switching mechanism 4 is disposed between the output shaft 7 of the torque converter 2 and the input shaft 24 of the belt-type continuously variable transmission 20, and is provided from the engine 1 via the torque converter 2. The input rotation is input to the continuously variable transmission mechanism 20 via the forward / reverse switching mechanism 4.
The continuously variable transmission 20 is a hydraulic continuously variable transmission that performs shift control and the like by hydraulic control described later.

The stepless speed change mechanism 20 will be described in more detail. The stepless speed change mechanism 20 includes a primary pulley (rotating element of the stepless speed change mechanism 20) 21, a secondary pulley 22, and a belt 23. The rotation input to the primary shaft 24 from the inversion switching mechanism 4 is input to the secondary pulley 22 via the belt 23 from the primary pulley 21 coaxially integrated with the primary shaft 24.

The primary pulley 21 and the secondary pulley 22 are respectively two sheaves 21a, 21 which rotate integrally.
1b, 22a and 22b. One of the sheaves 21a, 22a is a fixed sheave fixed in the axial direction, and the other sheave 21b, 22b is a movable sheave movable in the axial direction by hydraulic actuators (hydraulic pistons) 21c, 22c.

The hydraulic pistons 21c and 22c are supplied with control oil pressure obtained by pressurizing hydraulic oil in an oil tank 61 with an oil pump 62, and the movable sheave 2
The pressing force of the fixed sheaves 21a and 22a of the first sheaves 1b and 22b is adjusted. Secondary pulley 22
The hydraulic piston 22c has a pressure regulating valve (line pressure regulating valve)
The line pressure adjusted by the pressure 63 is applied to the hydraulic piston 21 c of the primary pulley 21, and the hydraulic oil adjusted by the pressure adjusting valve 63 and then adjusted by the flow rate control valve (speed ratio adjusting valve) 64 is adjusted. is supplied, the hydraulic fluid is adapted to act as a hydraulic adjustment speed ratio (primary pressure) P _P. The pressure regulating valve 63 is controlled by duty-controlling a line pressure control solenoid 63A by an electric signal. The flow control valve 64 is controlled by performing duty control on a shift control solenoid 64A with an electric signal, and is also referred to as a shift solenoid valve.

The line pressure should be as low as possible within a range in which power transmission can be ensured by avoiding slippage of the belt 23, so as to reduce the energy loss due to the oil pump 62 and the durability of the transmission itself. Is important in raising
The belt tension control pressure (pressure corresponding to the line pressure) Pout is set based on the transmission torque and a value corresponding to the belt hanging radius of the secondary pulley 22, and the pressure regulating valve 63 is controlled based on the belt tension control pressure Pout. Then, the line pressure is controlled by adjusting the discharge pressure of the oil pump 62.

Further, the primary pressure P _P applied to the hydraulic piston 21c of the line pressure applied to the hydraulic piston 22c P _L and the primary pulley 21 of the secondary pulley 22, the command signal of the controller (electronic control control unit = ECU) 50 , Respectively. That is, the ECU 50 includes an engine speed sensor (crank angle sensor or cam angle sensor) 4
1, throttle opening sensor 46, primary pulley 21
, A secondary rotation sensor 44 for detecting the rotation speed (rotation speed) of the secondary pulley 22, a line pressure sensor 45 for detecting line pressure, and a gear ratio adjustment hydraulic pressure (primary rotation sensor 43). Each detection signal of a primary pressure sensor (hydraulic pressure detecting means) 47 for detecting the pressure P _P , an A / F sensor 48, and an oil temperature sensor (not shown) for detecting the oil temperature of the working oil is inputted,
In U50, based on these detection signals, each pulley 2
A pressure regulating valve 63 and a flow rate control valve 64 provided in a hydraulic supply system for the first and the second 22 are controlled.

Then, as shown in FIG.
Reference numeral 50 denotes control of the above-described flow control valve 64 (speed ratio control).
(Shift control means or primary pressure control means) 52 and a function (line pressure control means) 53 for controlling the pressure regulating valve 63 (line pressure control).
In particular, as shown in FIG. 1, the speed change control means 52 includes, as shown in FIG. 54, pressure feedback control means 55 for performing pressure feedback control on the flow control valve 64, and switching means 56 for switching between rotation speed feedback control and pressure feedback control.

Among them, the rotation speed feedback control means 54 provides a parameter [here, a parameter corresponding to the vehicle speed of the vehicle.
Target primary rotation setting means for setting a target rotation speed of the primary pulley 21 from the rotation speed of the secondary pulley 22 corresponding to the vehicle speed (secondary rotation speed)] and the load of the engine mounted on the vehicle (here, the accelerator opening). 54
A and a calculating means (subtractor) for calculating a deviation ΔN _P (= N _PT −N _P ) between the actual rotation speed N _P of the primary pulley 21 detected by the primary rotation sensor 43 and the target rotation speed N _PT.
54B and this deviation ΔN _P is corrected by PID correction [proportional correction (P
Correction), the integral correction (I correction), the PID correction unit 54C for performing differential correction (D Correction)], PID on the deviation .DELTA.N _P
Based on the corrected control amount (shift duty),
The actual rotation speed N _P of the primary pulley 21 is equal to the target rotation speed N _PT
The feedback control of the flow control valve (speed ratio adjusting valve) 64 is performed so that

The pressure feedback control means 55
Includes a target primary pressure setting means for setting the P _PT (target hydraulic pressure setting means) 55A (target primary pressure as a target hydraulic pressure) the target value of the primary pressure from the input torque inputted to the belt-type continuously variable transmission 20, the primary Calculation means for calculating a deviation ΔP _P (= P _PT −P _P ) between the primary pressure (operating oil pressure applied to the hydraulic piston 21c of the primary pulley 21) P _P detected by the pressure sensor 47 and the target primary pressure P _PT. a subtractor) 55B, PI on the deviation [Delta] P _P
PID correction means 55C for performing D correction [proportional correction (P correction), integral correction (I correction), differential correction (D correction)], and a control amount (shift duty) obtained by performing PID correction on this deviation ΔP _P based, as the actual primary pressure P _P becomes the target primary pressure P _PT flow control valve (gear ratio control valve) 6
4 is feedback-controlled.

It should be noted that the input torque Tin to the primary pulley 21 is equal to the output torque Te during steady rotation of the engine,
It can be calculated from the increased output torque ΔTe and the torque ratio t of the torque converter 2 based on the following equation. Tin = (Te + ΔTe) × t In the above equation, the sum (Te + ΔTe) of the output torque Te during steady rotation and the engine torque increase ΔTe corresponds to the output torque of the engine 1, and this engine output torque (T
e + ΔTe) is multiplied by the torque ratio t to be input to the primary pulley 21 of the continuously variable transmission mechanism 20 in accordance with the torque ratio t.

The output torque Te at the time of steady rotation of the engine in the above equation can be estimated from the engine speed Ne detected by the engine speed sensor 41 and the throttle opening θ detected by the throttle opening sensor 46. However, here, the output torque Te is determined using a map in which the output torque Te is made to correspond to the engine rotation speed Ne and the throttle opening θ. Note that the output torque Te
Is the engine speed Ne and the intake charge efficiency A
/ Ne, the engine speed Ne and the average effective pressure (torque / displacement amount; target Pe), or the engine speed Ne and the boost pressure.

The increased output torque ΔTe is an engine torque that increases when the fuel supply amount to the engine is increased more than usual, such as during warm-up or acceleration of the engine. Since the increase in the fuel supply amount at this time corresponds to the decrease in the air-fuel ratio of the air-fuel mixture, here, based on the air-fuel ratio detection information of the A / F sensor 47 provided in the exhaust passage,
The engine torque increase ΔTe is determined.
If the A / F sensor 47 is not provided, the engine torque increase ΔTe may be obtained based on information on the target air-fuel ratio for engine air-fuel ratio control.

The torque ratio t is expressed by the input / output speed ratio of the torque converter 2 [the output rotation speed of the torque converter 2 (= the rotation speed Nin of the primary pulley 21 of the continuously variable transmission mechanism 20 is changed to the input rotation speed of the torque converter 2 (= the rotation speed of the engine 1). (Nin / Ne) divided by the speed Ne) .In the switching unit 56, the flow rate control valve 64 is normally controlled by the rotation speed feedback control by the rotation speed feedback control unit 54. When it is detected that the vehicle is in a substantially stopped state (extremely low speed running state or stopped state), the flow rate control valve (hydraulic control system) 64 is switched from the rotational speed feedback control to the pressure feedback control by the pressure feedback control means 55. Is switched.

[0023] In the present embodiment, the vehicle is whether in a substantially stopped state, indirectly corresponding to the rotational speed (the secondary rotational speed) N _S and the vehicle speed of the secondary pulley 22 corresponding directly to the vehicle speed The determination is made based on the rotation speed (primary rotation speed) N _P of the primary pulley 21. That is, while the vehicle is traveling, when the secondary rotation speed N _S is preset small threshold N into the _S1 less than or primary speed N _P reaches a preset small threshold value N _P1 or less, vehicle Is determined to be substantially stopped. Conversely, when the vehicle is in a substantially stopped state, the secondary rotation speed N _S becomes equal to or more than a predetermined small threshold value N _S2 (> N _S1 ), and the primary rotation speed N _P becomes a predetermined small threshold value N _S. When it becomes _P2 (> N _P1 ) or more, it is determined that the vehicle has returned to the running state.

As described above, it is determined whether or not the vehicle has substantially stopped and whether or not the vehicle has returned to the running state using both the secondary rotation speed N _S and the primary rotation speed N _P. For reasons. That is, when the primary rotation speed cannot be accurately detected, the primary rotation speed cannot be naturally feedback-controlled, and when the secondary rotation speed cannot be accurately detected,
This is because the primary rotation speed cannot be set as a target, and thus the primary rotation speed cannot be feedback-controlled.

Further, based on the information of the two rotation speed sensors, the primary rotation sensor 43 and the secondary rotation sensor 44, when the detected values of both the sensors 43, 44 become equal to or more than the respective threshold values N _S2 , N _P2 , the vehicle is _stopped. By determining that the vehicle has returned to the running state, it is possible to quickly and reliably determine that the vehicle has returned to the running state.
The reason why hysteresis is provided for the determination thresholds N _S1 and N _S2 and N _P1 and N _P2 is to prevent hunting of control and realize stable control.

In the present embodiment, the gear ratio is controlled to full / low while appropriately securing the primary pressure in the pressure feedback control. In other words, when controlling the gear ratio to full low, the primary pressure is made lower than the line pressure. At this time, the primary pressure is appropriately reduced while recognizing the actual primary pressure. Of course, the switching means 56 returns the control mode of the flow control valve 64 from the pressure feedback control to the rotation speed feedback control when the vehicle changes from a substantially stopped state to a running state.

The flow rate control valve 64 is controlled by controlling the duty of a shift control solenoid 64A. The control duty of the shift control solenoid 64A is calculated by an arithmetic means (adder) 58 by a rotational speed feedback control means. The deviation ΔN _P calculated by
D-corrected control amount (shift duty) or deviation Δ calculated by pressure feedback control means 55
Control variable subjected to PID correction P _P (shift duty)
Is added to the shift reference duty calculated by the shift reference duty calculator 57 from the oil temperature, the line pressure, the gear ratio, and the input rotation speed. The oil temperature,
The line pressure and the input rotation speed can be obtained from, for example, the detection results of the hydraulic pressure sensor, the line pressure sensor 45, and the engine rotation speed sensor 41, and the gear ratio can be obtained by, for example, the primary rotation speed and the secondary rotation speed detected by the primary rotation sensor 43. It can be calculated from the primary rotation speed detected by the rotation sensor 44.

Since the shift control device for a vehicle hydraulic continuously variable transmission according to one embodiment of the present invention is configured as described above, shift control is performed, for example, as shown in the flowchart of FIG. . That is, first, step S1
0, the shift reference duty calculating means 57 calculates the oil temperature,
A shift reference duty is calculated from the line pressure, the speed ratio, and the input rotation speed. Next, in step S20, the flag F is set to 1
It is determined whether or not. The flag F is set to 1 when it is determined that the vehicle is in a running state, and is set to 0 when it is determined that the vehicle is in a substantially stopped state.

Here, for example, in the previous control cycle, the vehicle
If it is determined that the vehicle is in the traveling state, step S30, step
Proceeding to step S40, in step S30 secondary rotation
Number N _SIs a preset threshold N_S1Greater than or threshold
N_S1It is determined whether the following conditions are satisfied.
Mali speed N_PIs a preset threshold N_P1Greater than
Ruka threshold N_P1It is determined whether or not:

In step S30, it is determined that the secondary rotation speed N _S is larger than the threshold value N _S1.
If it is determined at 40 that the primary rotation speed N _P is greater than the threshold value N _P1 , the vehicle is in the running state,
The rotation speed feedback control means 54 controls the flow control valve 6 so that the rotation speed of the primary pulley 21 becomes a target value.
4 is controlled.

In other words, the process proceeds to step S50, where the target primary rotation setting means 54A sets a parameter (here, secondary rotation speed) corresponding to the vehicle speed of the vehicle and the load of the engine mounted on the vehicle (here, accelerator opening).
Then, the target rotation speed of the primary pulley 21 is set.
Then, the process proceeds to step S60, in which the calculating means 54B calculates a deviation ΔN _P (= N _PT −N _P ) between the actual rotation speed N _P of the primary pulley 21 and the target rotation speed N _PT, and calculates PID.
The correction means 54C performs PID correction on the deviation ΔN _P.

Furthermore, holding the flag F to 1 at step S70, the process proceeds to step S80, and the shift reference duty calculated in step S10, have been subjected to PID correction shift duty (deviation .DELTA.N _P calculated in step S60 ), The shift control solenoid 64A is driven by duty control. On the other hand, if it is determined in step S30 that the secondary rotation speed N _S is equal to or less than the threshold value N _S1 , or if it is determined in step S40 that the primary rotation speed N _P is equal to or less than the threshold value N _P1 , the vehicle Assuming that the vehicle has almost stopped, the pressure feedback control means 5
5, the flow control valve 64 is controlled such that the hydraulic pressure acting on the primary pulley 21 becomes the target value. That is, the process proceeds to step S110, and the target primary pressure setting unit 55
A, a target value (target primary pressure) P of the primary pressure is obtained from the input torque input to the belt-type continuously variable transmission 20.
Set _PT . Then, the process proceeds to step S120, where the calculating means 55B calculates a deviation ΔP _P (= P _PT −P _P ) between the actual primary pressure P _P and the target primary pressure P _PT, and calculates P P
PID correction is performed on the deviation ΔP _P by ID correction means 55C.

Further, the flag F is set to 0 in step S130.
, And the process proceeds to Step S80, and Step S10
The shift control solenoid 64A is based on the shift reference duty calculated in step S120 and the shift duty calculated in step S120 (the control amount obtained by subjecting the deviation ΔP _P to PID correction).
Are driven by duty control. Also, the flag F as thus vehicle became substantially stopped state is set to 0, step S90 from step S20, the process proceeds to step S100, the threshold value N of step in S90 the secondary rotation speed N _S is set in advance determining whether a _S2 above, primary speed N _P in step S100 is equal to or preset threshold value N _P2 or more.

If it is determined in step S90 that the secondary rotation speed N _S is less than the threshold value N _S2 , or if it is determined in step S100 that the primary rotation speed N _P is less than the threshold value N _P2 , the vehicle Holds the substantially stopped state, so that the flow control valve 64 is pressure-feedback controlled in steps S90, S100, and S80. Further, the flag F is held at 0 in step S130.

On the other hand, in step S90, it is determined that the secondary rotation speed N _S is equal to or more than the threshold value N _S2 , and
If it is determined in step 100 that the primary rotation speed N _P is equal to or greater than the threshold value N _P2 , the vehicle has returned to the running state, and the flow rate control valve 64 is feedback-controlled in steps S50, S60, and S80. Also,
In step S70, the flag F is set to 1.

As described above, when the vehicle is traveling normally without being in a substantially stopped state (an extremely low speed traveling state or a stopped state), the switching means 56 selects the rotation number feedback control by the rotation number feedback control means 54 and the flow rate control valve 64. The speed change ratio is controlled by duty control of the speed change control solenoid 64A using the speed feedback to control the speed ratio of the primary pulley so that the speed ratio is optimized by the speed feedback control.

On the other hand, when the vehicle is in a substantially stopped state (an extremely low-speed running state or a stopped state), the switching means 56 switches from the rotation speed feedback control by the rotation speed feedback control unit 54 to the pressure feedback control by the pressure feedback control unit 55. And the pressure feedback control causes the shift control solenoid 64 of the flow control valve 64 to operate.
The A and duty control, and controls the adjusting gear ratio primary pressure P _P, even when the vehicle is is difficult to detect the rotational speed, such as the actual rotation speed N _P of the primary pulley 21 to a substantially stopped state , While controlling the primary pressure to an appropriate value (target primary pressure) by pressure feedback control,
The gear ratio can be controlled to full low. Thus, for example, without the primary pressure becoming too high,
It is also possible to avoid a situation in which the gear ratio gradually shifts to the overdrive side when traveling on a congested road, and good startability is maintained. In addition, the belt pressure at the time of restarting can be reliably avoided without the primary pressure becoming excessively low.

The present invention is not limited to the above-described embodiment, but can be implemented with various modifications without departing from the spirit of the present invention. For example, in this embodiment, when the vehicle is substantially stopped, the gear ratio is controlled to be full low, but the control of the gear ratio is not limited to full low. That is, it is conceivable to control the state to an intermediate speed ratio expected from the relationship between the line pressure and the primary pressure.

The determination of whether the vehicle is running or substantially stopped may be based on only one of the secondary rotation speed N _S and the primary rotation speed N _P , or another parameter related to the vehicle speed. Further, the hydraulic control systems 63 and 64 are not limited to duty solenoid control, and other controls such as position control using a linear solenoid can be applied.

The present invention is not limited to the belt type, but can be widely applied to a hydraulic type continuously variable transmission, and can be applied to, for example, a toroidal type.

[0041]

As described above in detail, according to the shift control device for a hydraulic continuously variable transmission for a vehicle of the present invention, when the vehicle is substantially stopped, that is, when the vehicle is traveling at extremely low speed or stopped. The gear ratio can be reliably controlled to a target value (for example, full low) while securing the hydraulic pressure supplied to the rotating element.
Further, since the hydraulic pressure does not become excessively high, it is possible to avoid a situation in which the gear ratio gradually shifts to the overdrive side when traveling on a congested road, and the startability is maintained satisfactorily. Further, since the hydraulic pressure does not become excessively low, belt slip at the time of restart can be reliably avoided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main configuration of a shift control device of a hydraulic continuously variable transmission for a vehicle as one embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a power transmission system of a vehicle with a hydraulic continuously variable transmission according to one embodiment of the present invention;
(A) is a schematic configuration diagram of a power transmission system including the continuously variable transmission, and (b) is a configuration diagram of the continuously variable transmission.

FIG. 3 is a flowchart showing the control performed by a shift control device for a vehicle hydraulic continuously variable transmission as one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 20 Hydraulic continuously variable transmission 21 Primary pulley (rotating element) 47 Primary pressure sensor (oil pressure detecting means) 52 Shift control means 53 Line pressure control means 54 Speed feedback control means 54A Target primary rotation setting means 55 Pressure feedback control Means 55A Target primary pressure setting means (target oil pressure setting means) 56 Switching means 63 Pressure regulating valve (line pressure regulating valve) 64 Flow control valve (hydraulic control system, speed ratio regulating valve)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 63:06 F16H 63:06 (72) Inventor Toru Hashimoto 5-33-8 Shiba 5-chome, Minato-ku, Tokyo Mitsubishi F-term in the Automotive Industry Co., Ltd. (reference) 3J052 AA04 CA21 CB01 CB16 FB35 GC13 GC23 GC42 GC46 GC73 HA11 KA01 LA01

Claims (1)

[Claims] 1. A target rotational speed of a rotary element is set from a vehicle speed of a vehicle and a load of an engine mounted on the vehicle, and a hydraulic control system of the rotary element is set so that an actual rotational speed is equal to the target rotational speed. In a shift control device for a vehicle hydraulic continuously variable transmission having a rotation speed feedback control unit for performing feedback control, a hydraulic pressure detection unit that detects an actual hydraulic pressure supplied to the hydraulic control system, and supplied to the hydraulic control system Target hydraulic pressure setting means for setting a target hydraulic pressure; and pressure feedback for feedback controlling a hydraulic control system of the rotary element so that the actual hydraulic pressure detected by the hydraulic pressure detecting means becomes the target hydraulic pressure set by the target hydraulic pressure setting means. Control means for controlling the hydraulic pressure control system of the rotating element by rotation speed feedback control by the rotation speed feedback control unit in a normal state, so that the vehicle is substantially stopped. Switching means for switching the control of the hydraulic control system of the rotary element from the rotation speed feedback control to the pressure feedback control by the pressure feedback control means when the rotation speed is detected. Shift control device for hydraulic continuously variable transmission.