JP2718049B2 - Control device for continuously variable transmission - Google Patents

Description

The present invention relates to a control device for a continuously variable transmission.

(B) Conventional technology A conventional control device for a continuously variable transmission is disclosed in JP-A-61-1053.
There is one disclosed in Japanese Patent No. 51. The control device for a continuously variable transmission shown here has a solenoid valve for controlling a lock-up clutch. That is, the lock-up control valve is controlled by the solenoid valve whose duty ratio is controlled, whereby the lock-up clutch is engaged or released. The solenoid valve is also configured to control the supply pressure to the forward clutch or the reverse brake in the idle state. For this purpose, a shift control valve operated by a shift control actuator is used. That is, the signal pressure obtained by the solenoid valve is supplied to the lock-up control valve in a normal shift state, but when the shift control actuator operates to a position exceeding the maximum speed ratio, the signal pressure of the solenoid valve is adjusted by the hydraulic pressure. Supplied to the throttle valve. In the fully closed state of the throttle, the speed change actuator is configured to operate at a position exceeding the maximum speed ratio described above. Since the oil pressure supplied to the forward clutch or the reverse brake is adjusted by the throttle valve, the engaged state of the forward clutch or the like can be controlled by the solenoid valve in the idle state, and thereby the creep speed in the idle state can be reduced. Can be controlled.

(C) Problems to be Solved by the Invention However, in the above-described conventional continuously variable transmission control device, if a failure occurs in a lock-up control hydraulic circuit or the like, the lock-up occurs at the moment when the accelerator pedal is depressed. There is a problem that the clutch is engaged to cause an engine stall, and conversely, the vehicle starts quickly. That is, when the solenoid valve fails in the drain state, when the pressure source which is the hydraulic pressure source of the solenoid valve and the pressure regulating valve sticks, or when the orifice or the filter becomes clogged, the control signal pressure of the solenoid valve becomes zero. . When the throttle is fully closed in this failure state, the hydraulic pressure of the forward clutch and the like is controlled by the solenoid valve. However, since the hydraulic pressure of the solenoid valve is 0, the hydraulic pressure supplied to the forward clutch is the lowest. And the forward clutch is released. When the accelerator pedal is depressed from this state, the shift actuator operates, and the lock-up clutch is controlled by the solenoid valve. However, since the signal pressure of the solenoid valve is 0, the lock-up clutch is engaged. Therefore, when the accelerator pedal is depressed, the forward clutch is connected and the lock-up clutch is engaged. As a result, an engine stall or a rapid start is caused. An object of the present invention is to solve such a problem.

(D) Means for Solving the Problems The present invention solves the above problems by fixing the shift actuator at a position exceeding the maximum speed ratio when the lock-up control device fails. That is,
A control device for a continuously variable transmission according to the present invention includes a shift control actuator that controls a gear ratio of the continuously variable transmission, and a lockup control actuator that controls operation of a lockup clutch of the fluid transmission device, When the shift control actuator is located at a position corresponding to a speed ratio exceeding the maximum speed ratio of the continuously variable transmission, the lockup control actuator is configured to be unable to engage the lock-up clutch. A failure detecting means for detecting that a failure in which a lock-up clutch is always engaged in a device for lock-up control has occurred, and a failure has been detected by the failure detecting means. In case of failure, the gearshift actuator is fixed at a position corresponding to the gear ratio exceeding the maximum gear ratio. It is characterized by having a stage, a.

(E) Action Failure occurs in the lock-up control hydraulic circuit, etc.
In a case where the lock-up clutch is instructed to be engaged, a failure is detected by the failure detection unit, and a signal indicating the failure is input to the failure-time-speed actuator fixing unit. As a result, the speed change actuator is fixed at a position exceeding the maximum speed ratio. In this state, the lock-up control actuator cannot control the lock-up clutch, and the lock-up clutch is held in the released state. Therefore, traveling can be continued for the time being in the maximum gear ratio state and the lock-up release state. If the malfunction speed-change actuator fixing means is operated only when the vehicle speed is equal to or lower than a predetermined vehicle speed, the vehicle can be driven while performing a gear shift with the lock-up clutch engaged at a speed higher than the predetermined vehicle speed.

(F) Embodiment FIG. 2 shows a power transmission mechanism of the continuously variable transmission. This continuously variable transmission has a fluid coupling 12, a forward / reverse switching mechanism 15,
It has a V-belt type continuously variable transmission mechanism 29, a differential device 56, and the like, and can transmit the rotation of the output shaft 10a of the engine 10 to the output shafts 66 and 68 at a predetermined speed ratio and rotation direction. The continuously variable transmission includes a fluid coupling 12 (a lock-up oil chamber 12a, a pump impeller 12b, a turbine runner 12c
Etc.), a rotating shaft 13, a drive shaft 14, a forward / reverse switching mechanism 15, a drive pulley 16 (a fixed cone member 18, a drive pulley cylinder chamber 20 (chambers 20a and 20b), a movable cone member 22, a groove).
22a etc.), planetary gear mechanism 17 (consisting of sun gear 19, pinion gear 21, pinion gear 23, pinion carrier 25, internal gear 27, etc.), V-belt 24, driven pulley 26 (fixed cone member 30, driven pulley cylinder Chamber 32, movable cone member 34, etc.), driven shaft 28, forward clutch 40, drive gear 46, idler gear 48, reverse brake 5
0, idler shaft 52, pinion gear 54, final gear 4
4, pinion gear 58, pinion gear 60, side gear 62,
It is composed of a side gear 64, an output shaft 66, an output shaft 68, etc., but detailed description thereof will be omitted. The configuration of a portion whose description has been omitted is described in JP-A-61-105353 filed by the present applicant.

FIG. 3 shows a hydraulic control device of the continuously variable transmission. The hydraulic control device includes an oil pump 101, a line pressure regulating valve 102, a manual valve 104, a shift control valve 106, an adjustment pressure switching valve 108, a shift motor (step motor) 110, a shift operation mechanism 112, a throttle valve 114, a constant pressure. It has a pressure regulating valve 116, a solenoid valve 118, a coupling pressure regulating valve 120, a lock-up control valve 122, etc., which are connected to each other as shown in the drawing, and a forward clutch 40, a reverse brake 50, The fluid coupling 12, the lock-up oil chamber 12a, the drive pulley cylinder chamber 20, and the driven pulley cylinder chamber 32 are also connected as illustrated. Detailed description of these valves and the like will be omitted. The parts whose description is omitted are described in the above-mentioned Japanese Patent Application Laid-Open No. 61-105353. Each reference numeral in FIG. 3 indicates the following member. Pinion gear 110a,
Tank 130, strainer 131, oil passage 132, relief valve 133,
Valve hole 134, ports 134a-e, spool 136, land 136a-
b, oil passage 138, one-way orifice 139, oil passage 140, oil passage 14
2, one-way orifice 143, valve hole 146, ports 146a-g,
Spool 148, lands 148a-e, sleeve 150, spring 152, spring 154, transmission ratio transmission member 158, oil passage 164,
Oil passage 165, orifice 166, orifice 170, valve hole 172, port 172a-e, spool 174, land 174a-c, spring 175, oil passage 176, orifice 177, lever 178, oil passage 17
9, pin 181, rod 182, lands 182a-b, rack 182
c, pin 183, pin 185, valve hole 186, port 186a-d, oil passage
188, oil passage 189, oil passage 190, valve hole 192, ports 192a-g, spool 194, lands 194a-e, negative pressure diaphragm 198, orifice 199, orifice 202, orifice 203, valve hole 20
4, ports 204a-e, spool 206, lands 206a-b, spring 208, oil passage 209, filter 211, orifice 21
6, port 222, solenoid 224, plunger 224a, spring 225, valve hole 230, ports 230a-e, spool 232,
Lands 232a-b, spring 234, oil passage 235, orifice
236, valve hole 240, port 240a-h, spool 242, land 2
42a-e, oil passage 243, oil passage 245, orifice 246, orifice 247, orifice 248, orifice 249, choke throttle valve 250, relief valve 251, choke throttle valve 252,
Holding valve 253, oil passage 254, cooler 256, cooler holding valve 25
8, orifice 259, changeover detection switch 278.

FIG. 4 shows a shift control device 300 for controlling the operations of the step motor 110 and the solenoid 224. Shift control device 300
Is an input interface 311, a reference pulse generator 312,
CPU (central processing unit) 313, ROM (read only memory) 3
14. It has a RAM (random access memory) 315 and an output interface 316, these are the address bus 319
And a data bus 320. The shift control device 300 includes an engine rotation speed sensor 301, a vehicle speed sensor 302, a throttle opening sensor 303, a shift position switch 304, a turbine rotation speed sensor 305, an engine coolant temperature sensor 306, a brake sensor 307, and a switching detection switch 298. Signal directly or waveform shaper 3
08, 309 and 322, and input through the AD converter 310,
On the other hand, the stepping motor 1 through the amplifier 317 and the lines 317a-d
A signal is output to 10 and a signal is also output to the solenoid 224, but a detailed description thereof will be omitted.
The configuration of a portion whose description is omitted is described in the above-mentioned Japanese Patent Application Laid-Open No. 61-105353.

5 and 6 show the contents of control performed by the transmission control device 300. FIG. The parts other than those described later are the same as those described in the above-mentioned JP-A-61-105353, and the description thereof will be omitted.

The part of the control flow that is directly related to the present invention will be described. After searching for a shift pattern in step 626 or the like shown in FIG. 6, it is determined whether there is a failure in the lockup control system (step 652). Whether or not there is a failure in the lockup control system is performed according to a flow shown in FIG. 7 described later. Failure Continue to step 630 if there is no, on the other hand if there is a failure to the zero target pulse number P _D (same 654), the process proceeds to step 630. In step 630 or less, control is performed such that the actual pulse number P _A coincides with the number of pulses P _D as a target. P _D = 0 is a value smaller than the pulse number of P ₁ corresponding to the maximum speed ratio set in step 608. That is, when P _D = 0, the step motor 110 is at a position exceeding the maximum speed ratio.

The failure detection in step 652 is performed as shown in FIG. That is, it is first determined whether or not a lock-up engagement command has been issued (700), and if the lock-up engagement command has not been issued, the absolute value of the difference between the engine rotation speed _NE and the turbine rotation speed _NT is determined. It is determined whether the value is equal to or less than a predetermined value α (702).
The lock-up failure flag is set (704). If the above condition is not satisfied, the lock-up failure flag is cleared (706). Accordingly, if the lock-up release is instructed and the engine rotational speed _NT matches (when the lock-up clutch is engaged), it is determined that a failure has occurred. .

After all, by the control, if there is a fault in the control system of the lock-up clutch is a target pulse number P _D is 0,
Since the step motor 110 is controlled based on this,
The step motor 110 has a pulse number P ₁ corresponding to the maximum speed ratio.
, The operation is performed on the side with a larger gear ratio. In this state, the adjustment pressure switching valve 108 is fixed at the lower half in FIG. 3, and the oil passage 109 and the oil passage 189 are connected. On the other hand, since the port 186a is closed, the lockup control valve 122 is located on the lockup release side, and the lockup clutch is released. As a result, the gear ratio is fixed to the maximum state and the lock-up clutch is released, so that traveling can be continued for the time being.
In the case of this embodiment, the characteristic of the throttle pressure regulated by the throttle valve 114 is such that a predetermined oil pressure can be obtained even when the oil pressure does not act on the port 192g, and the malfunction occurs when the solenoid valve 118 is in the drain state. Even in this case, a minimum required hydraulic pressure is supplied to the forward clutch 40 or the reverse brake 50. Therefore, the vehicle can travel as described above. Also, creep running can be performed.

As shown in FIG. 8, step 652 and step 6
Between 54, the vehicle speed V is to insert a step 653 to determine if it is less than the predetermined value V _1, to fix only the step motor 110 to the position of the pulse number 0 when the vehicle speed is below a predetermined value V ₁ Control will be performed. Therefore, the shift can be performed at a vehicle speed higher than a predetermined value, and the lock-up clutch can be engaged. By doing so, it becomes possible to travel relatively close to the normal body even at the time of failure.

(G) Effects of the Invention As described above, according to the present invention, when the control system of the lock-up clutch breaks down, the speed-change actuator is fixed in a state where the operation of the lock-up control actuator is disabled. As a result, the lock-up clutch is always in the released state, and the occurrence of troubles such as engine stall is prevented, so that traveling can be continued.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between components of the present invention, FIG. 2 is a diagram showing a power transmission mechanism of a continuously variable transmission, FIG. 3 is a diagram showing a hydraulic control circuit, and FIG. , FIGS. 5 and 6 are diagrams showing a control routine of a shift control, FIG. 7 is a diagram showing a failure determination routine, and FIG. 8 is a diagram showing another embodiment.

Claims (2)

(57) [Claims] A transmission control actuator for controlling a transmission ratio of the continuously variable transmission; and a lockup control actuator for controlling operation of a lockup clutch of the fluid transmission, wherein the transmission control actuator is continuously variable. In a control device for a continuously variable transmission configured to disable engagement of a lock-up clutch by a lock-up control actuator when it is at a position corresponding to a speed ratio exceeding a maximum speed ratio of the transmission, Failure detection means for detecting the occurrence of a failure in which the lock-up clutch is always engaged in the up-control device, and, if a failure is detected by the failure detection means, shifting the speed change actuator to exceed the maximum gear ratio. And a means for fixing the actuator for shifting during failure, which is fixed at a position corresponding to the ratio. Speed control device. 2. The control device for a continuously variable transmission according to claim 1, further comprising vehicle speed determining means, wherein the malfunction speed-change actuator fixing means operates only when the vehicle speed is lower than a predetermined vehicle speed.