JP3125537B2 - Control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a continuously variable transmission.

[0002]

2. Description of the Related Art A conventional control device for a continuously variable transmission is disclosed in Japanese Patent Publication No. 4-34027. The control device for the continuously variable transmission shown in the figure includes a torque converter with a lock-up mechanism, a V-belt type continuously variable transmission mechanism,
When a shift down is determined to be necessary based on the difference between the signal corresponding to the actual gear ratio and the signal corresponding to the target gear ratio, the lock must be made. The up-clutch is released. This intends to utilize the torque increasing effect of the torque converter.

[0003]

However, in the conventional control device for a continuously variable transmission, the lock-up clutch is disengaged when a quick downshift is required, and the engine speed increases. There is a problem that it may not be possible to use. That is, when the rapid downshift is performed, the engine rotational speed increases, but the rotational speed of the torque converter on the turbine shaft side also increases due to the shift of the V-belt continuously variable transmission mechanism. Although the speed ratio decreases and enters the torque increasing region, the speed ratio of the torque converter approaches 1 immediately after shifting starts, and the torque increasing effect is hardly obtained. An object of the present invention is to solve such a problem.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by controlling the shift speed of the rapid shift down gear so as to always utilize the torque increasing effect of the torque converter. That is, the control device for a continuously variable transmission according to the present invention, at the time of rapid downshift, shift
Delay the start time of the change in the ratio, and
Time when the vehicle speed is low compared to when it is high.
There is a shift delay unit that is set to be long and controls so that the end of the lock-up clutch release and the end of the gear shift coincide.

[0005]

The lock-up clutch is released at the time of rapid downshift. When the lockup clutch is disengaged, the continuously variable transmission mechanism makes the shift start time correspond to the vehicle speed and the vehicle speed is low
Sometimes delay longer than higher times
Control . Accordingly, a change in the rotation speed on the output side of the torque converter (a change in the rotation speed on the input side of the continuously variable transmission) is delayed with respect to a change in the rotation speed on the input side of the torque converter (change in the rotation speed of the engine). Therefore, the speed difference between the input side and the output side of the torque converter is always kept at a value considerably smaller than 1, and the torque increasing effect of the torque converter is obtained. Thereby, quick acceleration can be performed.

[0006]

FIG. 1 shows the relationship between the components of the present invention. FIG. 2 shows the torque converter 12 and the continuously variable transmission mechanism. The continuously variable transmission mechanism includes a forward / reverse switching mechanism 15, a V-belt type continuously variable transmission mechanism 29, a differential device 56, and the like, and controls the rotation of the turbine shaft 13 to a predetermined speed ratio and a predetermined rotational direction.
6 and 68. The torque converter 12 has a lock-up oil chamber 12a, a pump impeller 12b, a turbine runner 12c, a lock-up clutch 12d, a stator 12e, and the like, and transmits the rotation of an output shaft 10a of the engine 10 to a turbine shaft 13. be able to. More specifically, the continuously variable transmission mechanism includes a drive shaft 14, a forward / reverse switching mechanism 15, a drive pulley 16 (fixed cone member 18, a drive pulley cylinder chamber 20 (chamber 20a,
Chamber 20b), movable cone member 22, 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 (comprising a fixed cone member 30, a driven pulley cylinder chamber 32, a movable cone member 34, etc.), a driven shaft 28,
Forward clutch 40, drive gear 46, idler gear 4
8, a reverse brake 50, an idler shaft 52, a pinion gear 54, a final gear 44, a pinion gear 58, a pinion gear 60, a side gear 62, a side gear 64, an output shaft 66, an output shaft 68, and the like. The detailed description of is omitted. The configuration of the parts not described is described in Japanese Unexamined Patent Application Publication No.
It is described in JP-A-1-105353.

FIGS. 3, 4, 5 and 6 show a hydraulic control device for a continuously variable transmission. This hydraulic control device includes an oil pump 10
1. Line pressure regulating valve 102, manual valve 104, shift control valve 106, regulating pressure switching valve 108, step motor 11
0, transmission operation mechanism 112, throttle valve 114, constant pressure regulating valve 116, solenoid valve 118, coupling pressure regulating valve 1
20, a lock-up control valve 122, etc., which are connected to each other as shown in the drawing. The forward clutch 40, the reverse brake 50, the fluid coupling 12, the lock-up oil chamber 12a, the drive pulley The cylinder chamber 20 and the driven pulley cylinder chamber 32 are also connected as shown. Detailed description of these valves and the like will be omitted. The parts for which the description has been omitted are described in the above-mentioned JP-A-61-105353. 3, 4 and 5 indicate the following members. Pinion gear 110a, tank 130, strainer 131, oil passage 132, relief valve 133, valve hole 134, port 13
4a-e, spool 136, land 136a-b, oil passage 138, one-way orifice 139, oil passage 140, oil passage 1
42, one-way orifice 143, valve hole 146, port 1
46a-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, ports 172a-e, spool 174, lands 174a-c,
Spring 175, oil passage 176, orifice 177, lever 178, oil passage 179, pin 181, rod 182,
Lands 182a-b, rack 182c, pin 183, pin 185, valve hole 186, ports 186a-d, oil passage 18
8, oil passage 189, oil passage 190, valve hole 192, port 19
2a-g, spool 194, lands 194a-e, negative pressure diaphragm 198, orifice 199, orifice 2
02, orifice 203, valve hole 204, port 204a
-E, spool 206, lands 206a-b, spring 208, oil passage 209, filter 211, orifice 216, port 222, solenoid 224, plunger 224a, spring 225, valve hole 230, port 23
0a-e, spool 232, land 232a-b, spring 234, oil passage 235, orifice 236, valve hole 2
40, ports 240a-h, spool 242, land 2
42a-e, oil passage 243, oil passage 245, orifice 24
6, orifice 247, orifice 248, orifice 249, choke-type throttle valve 250, relief valve 25
1. Choke type throttle valve 252, pressure holding valve 253, oil passage 25
4, cooler 256, cooler pressure holding valve 258, orifice 2
59, changeover detection switch 298.

FIGS. 7, 8 and 9 show an electronic control unit 30 for controlling the operation of the step motor 110 and the solenoid 224.
Indicates 0. The electronic control unit 300 includes an input interface 311, a reference pulse generator 312, a CPU (central processing unit) 313, a ROM (read only memory) 314,
It has a RAM (random access memory) 315 and an output interface 316, which are connected by an address bus 319 and a data bus 320. The electronic control unit 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. Is directly or by the waveform shapers 308, 30
9 and 322 and input through the A / D converter 310, while signals are output to the stepper motor 110 through the amplifier 317 and lines 317a-d, and the solenoid 2
Signals are also output to 24, 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.

(First Embodiment of Shift Control) Next, a first embodiment of shift control at the time of kick down will be described based on a control flow shown in FIG. First, it is determined whether or not the flag F indicating whether or not the kick down state (rapid shift down state) is 0 (F = 0 indicates that the kick down state is not established) (step 102). F = 0
In the case of (2), that is, when the flag is not in the kick down state, it is determined whether or not the kick down state is set (No. 104). The kick down state is determined from the fact that the throttle opening is equal to or greater than a predetermined value and the rate of change of the throttle opening is equal to or greater than a predetermined value. In the kick down state, the flag F is set to 1 (10
6), reset the timer (108), and then
The SP, the throttle opening change speed ΔTVO, and the actual speed ratio ip are read (110). Next, it is determined whether or not the lock-up clutch 12d is engaged (112), and if it is engaged, the lock-up clutch 12d is released (114). Next, a shift control at the time of kick down (this will be described later) is performed (116), and then the lock-up clutch 12d is controlled (118), and the routine returns. Step 102
If F = 0 is not satisfied, that is, if the lock-up clutch 12d is in the engaged state, it is determined whether or not the timer t is larger than a predetermined value T1 (at 120).
Is smaller than T1, the routine returns. On the other hand, when t reaches T1, F is set to 0 (122), normal shift control is performed (124), and the routine continues to step 118. In the shift control at the time of kick down in step 116, the vehicle speed VS
The times t1, t2 and t3 shown in FIG. 11 are controlled in accordance with P, the change rate of the throttle opening ΔTVO, and the actual gear ratio ip. The time t1 is the duration of the lock-up clutch release signal, the time t2 is a time to delay the start of the change of the gear ratio, and the time t3 is from the start of the change of the gear ratio until the lock-up clutch 12d is completely engaged. It's time. The content of the control is, specifically, the vehicle speed VS
When P is small, it is difficult to enter the torque increasing operation region of the torque converter as compared with the case where P is large, so the time t2 is lengthened. Also, when the speed ratio ip is large, it is more difficult to enter the torque increasing operation region than when the speed ratio ip is small, so the time t2 is set longer. Also, the greater the change rate of the throttle opening ΔTVO, the longer the time t2,
Make it one hour longer. By changing the gear ratio as shown in FIG. 11, the speed ratio e of the torque converter, that is, the output rotation speed (the rotation speed of the turbine shaft 13) with respect to the input rotation speed (the rotation speed of the input shaft 10a) is changed. The ratio changes as shown in FIG. 11, and the torque ratio of the torque converter also changes as shown in FIG. Therefore, the torque ratio during kick down increases, and a larger driving force can be obtained, so that quick acceleration can be performed.

(Second Embodiment of Shift Control) A second embodiment of shift control at the time of kick down will be described with reference to a control flow shown in FIG. First, it is determined whether the flag F is 0 (step 202). When F = 0, that is, when the flag F indicates that the kick-down state is not established, it is determined whether or not the kick-down state has been established (No. 204). In the kickdown state, the flag F is set to 1 (206), and the timer is reset (20).
8) Then, the change speed of the vehicle speed VSP and the throttle opening △
The TVO and the actual speed ratio ip are read (No. 210).
Next, it is determined whether or not the lock-up clutch 12d is engaged (212), and if it is engaged, the lock-up clutch 12d is released (21).
4). Next, a shift control during kick down is performed (see
16, which will be described later), then controls the lock-up clutch 12d (218), and returns. If F = 0 in step 202, that is, if the flag F indicates that the lock-up clutch 12d is in the engaged state, the gear ratio e and the gear ratio change rate de / dt of the torque converter 12 are read. 220) It is determined whether or not the speed ratio change rate de / dt is greater than 0 and the speed ratio e is equal to or greater than a threshold value (speed ratio at which torque increase cannot be expected) e ₀ (221). Returns if the conditions do not match,
On the other hand, if the conditions match, the flag F is set to 0 (the
2) Normal shift control is performed (224), and step 2 is performed.
Continue to 18. In step 221, it is determined that the speed ratio change rate de / dt is greater than 0 because:
This is to prevent the lock-up clutch 12d from operating immediately after the lock-up clutch 12d is released.
In the gear change control at the time of kick down in step 216, the times t2 and t3 shown in FIG. 15 are controlled according to the vehicle speed VSP, the change speed ΔTVO of the throttle opening, and the actual gear ratio ip. The time t2 is a time for delaying the start of the change of the gear ratio, and the time t3 is a time from the start of the change of the gear ratio until the lock-up clutch 12d is completely engaged. The content of the control is, specifically, when the vehicle speed VSP is low, the torque converter 1 is lower than when the vehicle speed VSP is high.
2, since it is difficult to enter the torque increasing action region, the time t2 is lengthened. Also, when the speed ratio ip is large, it is more difficult to enter the torque increasing operation region than when the speed ratio ip is small, so the time t2 is set longer. In addition, the greater the change rate ΔTVO of the throttle opening, the longer the time t2. By changing the speed ratio as shown in FIG. 15 in this manner, the speed ratio e of the torque converter 12, that is, the output rotation speed (the rotation speed of the turbine shaft 13) with respect to the input rotation speed (the rotation speed of the input shaft 10a). 15 changes as shown in FIG. 15, and the torque ratio of the torque converter 12 also changes as shown in FIG.
It changes as shown in FIG. Therefore, the torque ratio during kick down increases, and a larger driving force can be obtained, so that quick acceleration can be performed. Also,
When the gear ratio e of the torque converter 12 is equal to or more than the threshold value e ₀ , that is, when the gear ratio is such that the torque increasing effect of the torque converter 12 cannot be expected, the gear shift control during kick down is not performed. Do). In the second embodiment, a torque increasing effect can be reliably obtained regardless of the skill of the timer setting.

In the first embodiment of the speed change control, the change of the speed ratio is first set in a range where the speed ratio does not change.
Next, the speed ratio changes linearly. However, as shown in FIG. 12, the speed ratio may be gradually changed to the target value in a state where the change speed is always positive. In addition,
For reference, a broken line in FIG. 12 shows a conventional characteristic (normal change ratio of the speed ratio). Furthermore, the lockup capacity at the time of coasting can be changed by the lockup variable switch 500 shown in FIG. This lock-up capacity is controlled by the duty ratio of the lock-up solenoid 224 so as to have the characteristics shown in FIG. 13 corresponding to the output of the lock-up variable switch 500. Here, if the duty ratio is, for example, 30%, the lock-up clutch is slightly slippery, and the shock when the accelerator is depressed is small. Also, the duty ratio is 80%
, The torque is transmitted directly.

[0012]

As described above, according to the present invention, when the shift start time of the quick shift down gear is changed during the lock-up clutch disengagement time and when the vehicle speed is low in accordance with the vehicle speed.
Since the delay time is delayed longer than when the vehicle is high , the torque converter can be operated in the torque increase region, and the vehicle can be rapidly accelerated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between components of the present invention.

FIG. 2 is a skeleton diagram of a continuously variable transmission.

FIG. 3 is a diagram showing a left part of a hydraulic control device of the continuously variable transmission.

FIG. 4 is a diagram showing a central portion of a hydraulic control device of the continuously variable transmission.

FIG. 5 is a diagram showing a right part of a hydraulic control device of the continuously variable transmission.

FIG. 6 is a diagram showing an arrangement relationship of FIGS. 3, 4, and 5;

FIG. 7 is a diagram showing a left part of the control unit.

FIG. 8 is a diagram showing a right part of the control unit.

FIG. 9 is a diagram showing an arrangement relationship between FIGS. 7 and 8;

FIG. 10 is a diagram showing a control flow.

FIG. 11 is a diagram showing change characteristics such as a speed ratio, a speed ratio, and a torque ratio.

FIG. 12 is a diagram showing a change characteristic of a gear ratio according to another embodiment.

FIG. 13 is a diagram illustrating characteristics of a lockup variable switch.

FIG. 14 is a diagram showing another control flow.

FIG. 15 is a diagram showing change characteristics such as a speed ratio, a speed ratio, and a torque ratio in the case of FIG. 14;

[Explanation of symbols]

 12 Torque converter 12d Lock-up clutch 300 Control unit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuaki Mochizuki Nissan Motor Co., Ltd. 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-3-172666 (JP, A) JP-A-63- 255133 (JP, A) JP-A-4-357362 (JP, A) JP-A-4-191564 (JP, A) JP-A-3-204473 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) F16H 47/06 F16H 59/00-63/48

Claims (3)

(57) [Claims] 1. A control device for a continuously variable transmission having a torque converter with a lock-up clutch and a continuously variable transmission mechanism, wherein a lock-up clutch is released at the time of rapid shift-down. Delay start time of gear ratio change
The delay time corresponds to the vehicle speed, and when the vehicle speed is low,
Set a longer delay time than when high, so that the end of lock-up clutch release coincides with the end of gear shifting.
A control device for a continuously variable transmission, comprising a shift delay means for controlling. 2. The control device for a continuously variable transmission according to claim 1, wherein the speed change delay means always sets a rate of change of the speed ratio from small to large to 0 or more. 3. The rapid shift-down is determined based on the fact that the speed of change of the engine load is equal to or greater than a predetermined value in the direction of increasing the engine load and the engine load is equal to or greater than the predetermined value. The control device for a continuously variable transmission according to any one of the preceding claims.