JPH03121358A - Speed change controller for continuously variable transmission - Google Patents

Abstract

PURPOSE:To reduce response delay of a hydraulic device for transmission by providing a correcting means for commanding a preset excessive target value which is excessive in the transmission direction in place of a target value for a predetermined time after transmission is started. CONSTITUTION:For a predetermined time after transmission is started, a target value which is excessive in the transmission direction than a target value acquired from a driving condition is commanded to a transmission actuator by a correcting means. Thus, a hydraulic device for transmission can make a quick response, and in the state that the predetermined time has passed, a deviation between the original target value and an actual value can be made small. Thus, overshoot is not generated in the subsequent transmission control. The same action can be obtained when the above control is carried out for the period till revolution speed of a driving pulley reaches a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a speed change control device for a continuously variable transmission.

(B) Prior Art A conventional speed change control device for a continuously variable transmission is disclosed in, for example, Japanese Patent Laid-Open No. 105351/1983. The gear change control device for the continuously variable transmission shown in this figure calculates a target input rotational speed from the vehicle speed and throttle opening, and performs feedback control so that the deviation between this and the actual input rotational speed becomes small. That is, the step motor, which is the speed change actuator, is commanded a rotation angle that is the sum of the motor rotation angle corresponding to the target speed ratio and the deviation multiplied by the gain. When the deviation becomes O, the actual input rotation speed matches the target rotation speed.

(c) Problems to be Solved by the Invention However, in the conventional shift control device for a continuously variable transmission as described above, a relatively large deviation occurs for a while after the start of the 5th gear shift due to the response delay of the shift hydraulic system. There is a problem in that a state in which a gear ratio that is deviated from the target gear ratio by the amount of feedback due to the deviation is commanded continues, resulting in a 5 overshoot. As a result, the driving feeling is poor, and the gear ratio is not controlled to a predetermined value during gear shifting, resulting in increased fuel consumption. The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention solves the above problems by operating the speed change actuator excessively in the speed change direction immediately after the start of the speed change.

That is, the speed change control device for a continuously variable transmission according to the present invention has the following features:
During a predetermined period of time (T1) after the start of the shift, a preset excessive target value (θ0) that is greater in the shift direction than the kneading is used instead of the target value (off) determined from the operating conditions.
It has a correction means (step 518) for instructing.

Note that it is also possible to operate the same correction means as described above until the drive pulley rotation speed reaches a predetermined value.

(e) Operation Once the shift is started, for a predetermined period of time, the shift actuator is commanded an excessive target value that is larger in the shift direction than the target value determined from the operating conditions. Therefore, the shift hydraulic system responds quickly, and after the predetermined time period has elapsed, the deviation between the original target value and the actual value can be kept small. Therefore, overshoot will not occur in subsequent speed change control. Note that the same effect can be obtained by performing the same control as above until the drive pulley rotational speed reaches a predetermined value.

(F) Embodiment FIG. 2 shows a power transmission mechanism of a continuously variable transmission. This continuously variable transmission has a fluid coupling 12 and a forward/reverse switching mechanism 15.
, (2) a belt type continuously variable transmission mechanism 29, a differential device 56, etc., and can transmit the rotation of the output shaft 10a of the engine 10 to the output shafts 66 and 68 at a predetermined gear ratio and rotation direction. This continuously variable transmission uses fluid coupling 1
2 (lock-up oil chamber 12a, pump impeller 12b
, turbine runner 12c, etc.), rotating shaft 13
, drive shaft 14, forward/reverse switching mechanism 15, drive pulley 16 (
Fixed conical member 18, drive pulley cylinder chamber 20 (chamber 2
0a, chamber 20b), movable conical member 22, groove 22a, etc.), planetary gear mechanism 17 (sun gear 19, pinion gear 21, pinion gear 23, pinion carrier 25)
, internal gear 27, etc.), v-belt 24,
Driven pulley 26 (consisting of fixed conical member 30, driven pulley cylinder chamber 32, movable conical member 34, etc.), driven wheel 28, forward clutch 40, drive gear 46, idler gear 48, reverse brake 50, idler shaft 52, binion gear 54, final gear 44, binion gear 58,
Binion gear 60, side gear 62, side gear 64,
Although it is composed of an output shaft 66, an output shaft 68, etc., a detailed explanation of these will be omitted. Note that the structure of the portions whose explanations are omitted are described in Japanese Patent Application Laid-Open No. 105353/1983 filed by the present applicant.

FIG. 3 shows the hydraulic control system for the continuously variable transmission. This hydraulic control device includes an oil pump 101 and a line pressure regulating valve 102.
, manual valve 104, speed change control valve 106, speed ratio command valve 108, step motor 110, speed change operation mechanism 112,
Throttle valve 114, constant pressure regulating valve 116, solenoid valve 11
8, a coupling pressure regulating valve 120, a lock-up control valve 122, etc., which are connected to each other as shown in the figure, and a forward clutch 40, a reverse brake 50, a fluid coupling 12, a lock-up oil The chamber 12a, the driving pulley cylinder chamber 20, and the driven pulley cylinder chamber 32 are also connected as shown. A detailed explanation of these valves and the like will be omitted. The parts whose explanation is omitted are described in the above-mentioned Japanese Patent Laid-Open No. 105353/1983. In addition, each reference numeral in FIG. 3 indicates the following members. Binion gear 110a, tank 130, strainer 131, oil passage 132, relief valve 133, valve hole 134, boats 134a-e, spool 136, land 136aNb1 oil passage 138, one-way orifice 139,
Oil passage 140, oil passage 142, one-way orifice 143, valve hole 146, boats 146a-g, spool 148, land 148axe, sleeve 15o1 spring 152,
Spring 154, gear ratio transmission member 158, oil passage 164
, oil passage 165, orifice 166, orifice 170,
Valve hole 172° boat 172a''-e, spool 174,
Land 174aNc, spring 175, oil passage 176,
Orifice 177, lever 178, oil passage 179, bottle 1
81, gear ratio command spool 182, land 182a P
-b, rack 182c, bin 183, bin 185, valve hole 186, boats 186a to d, oil passage 188, oil passage 189
, oil passage 190, valve hole 192, boat 192a Ng, spool 194, land 194aNe, negative pressure diaphragm 198, orifice 199, orifice 202, orifice 203, valve hole 204, boat 204axe, spool 206, land 206aNb1 spring 208, oil passage 209, filter 211, orifice 216, boat 222, solenoid 224/plunger 224a, spring 225, valve hole 230, boat 230aNe.

Spool 232, lands 232a-b, spring 23
4, oil passage 235, orifice 236, valve hole 240, bow 1-240a Nh, spool 242, land 242a
~e, oil passage 243, oil passage 245, orifice 246, orifice 247, orifice 248, orifice 249
, choke type throttle valve 250, relief valve 251, choke type throttle valve 252, pressure holding valve 253, oil passage 254, cooler 256, Taller pressure holding valve 258, orifice 25
9. Changeover detection switch 278° FIG. 4 shows a control unit 300 that controls the operation of the step motor 110 and the solenoid 224. The control unit 300 has a human power interface 3
11, reference pulse generator 312, CPU (central processing unit) 313, ROM (read only memory) 314, RA
M (random access memory) 315 and an output interface 316, which are connected to the address bus 3.
19 and data bus 320. This control unit 300 includes an engine speed sensor 301, a vehicle speed sensor 302, a throttle opening sensor 303, a shift position switch 304, a turbine speed sensor 305, an engine coolant temperature sensor 306, an idle switch 307, and a changeover detection switch 298. Signal directly or waveform shaper 308.3
09 and 322, and the AD converter 310, a signal is output to the step motor 110 through the force amplifier 317 and the line 317aNd, and the solenoid 2
Although signals are also output to 24, a detailed explanation of these will be omitted. The structure of the portions whose explanations are omitted are described in the above-mentioned Japanese Patent Application Laid-Open No. 105353/1983.

Control during gear change by the control unit 300 is performed according to the control flow shown in FIG. First, the vehicle speed SP, the throttle opening TVO, and the actual drive pulley rotation speed Nin of the drive pulley 16 are read (step 50).
2) Next, a shift pattern is searched based on the vehicle speed vSP and the throttle opening TVO, and the target drive pulley rotation speed T-Nin is determined (step 504). Next, the gear ratio i-new calculated in the previous routine is set as i・oILd (506), and the current gear ratio i-new is calculated based on the data read in this routine (508). . Note that C in step 508 is a constant. Next, it is determined whether i-old is the maximum transmission ratio LO (510), and if it is the maximum transmission ratio LO, it is determined whether i-new is smaller than the maximum transmission ratio LO. 512), and if it is small, T1 is set as the timer value (514). Step 5
10 and 512, in cases other than the above, the process proceeds to step 516 without setting the timer. Step 516
Then, determine whether the timer is 0 or not, and if the timer is not 0, set θ as the off value. 518) and proceeds to step 522.

On the other hand, if the timer is 0, the off value is
The value is searched (see FIG. 6) and obtained (step 520), and the process proceeds to step 522. In step 522, the target drive pulley rotation speed T-Nin and the actual drive pulley rotation speed Ni
Find the deviation e from n, then step motor rotation angle θ
m is calculated as θm=θff+ using the formula pXe+Kixe (ibid. 524). In addition, P and i
is the feedback gain. Next, the thus obtained θm is output, and the step motor 110 is rotated to θm (step 526). Then perform other controls (see 5.
28).

After all, when the shift from the maximum gear ratio LO is started by the above control, the off value is a value θ larger than the value corresponding to the target gear ratio for the predetermined time T1. (Excessive target value)
It is said that In other words, if the vehicle starts with a constant throttle opening, the vehicle will initially drive at the maximum gear ratio LO, and when the vehicle reaches a predetermined speed, the gear ratio will change from the maximum gear ratio to a smaller value. Start. If this is determined in steps 510 and 512, off is θ from this point on for time T1. It is said that

The value of this θ0 is the value (θI) near the maximum gear ratio in the relationship between the gear ratio and the rotation angle of the step motor shown in Figure 6.
It is considered to be a larger value. Therefore, the change over time of the rotation angle commanded to the step motor 110 is shown in Fig. 1, and the value on the small side of the gear ratio is discontinuously commanded at the same time as the speed change is started. become. Time T1
When the time period elapses, the original target value is restored. As mentioned above,
During time T1, the step motor rotation angle θ is much smaller than the original target value. is commanded, and in response, the spool 174 of the speed change control valve 106 is largely displaced toward the small speed ratio side, supplying a large amount of pressure oil to the drive pulley cylinder chamber 20, and causing a rapid speed change. Therefore, when the time T1 has elapsed, the drive pulley 16 has been displaced to the smaller gear ratio side, and the deviation e has become smaller. This results in
Actual step motor rotation angle θm immediately after 71 hours have passed.
becomes a state that coincides with the target motor rotation angle OFF. This prevents overshoot from occurring.

In the above embodiment, the off value for the time T1 set in the timer is θ. However, off is set to θ until the drive pulley rotational speed Nin reaches a predetermined value. Almost the same effect can be obtained even if the film is closed.

Further, in the above embodiment, θ. Although the value of was kept constant, θ changed over time. You can also reduce the value of . Further, it is also possible to adopt a larger value as the value of θ0 as the absolute value of the difference between the actual value and the target value at the start of the shift is larger.

(G) As described in detail, according to the present invention, an excessively excessive target value is commanded in the shifting direction at the initial stage of shifting, thereby reducing the response delay of the shifting hydraulic system. This reduces the deviation and prevents overshoot from occurring.

[Brief explanation of drawings]

Figure 1 is a diagram showing changes in the step motor rotation angle over time during gear shifting, Figure 2 is a diagram of the framework of the continuously variable transmission,
Figure 3 shows the hydraulic circuit of the continuously variable transmission, Figure 4 shows the control unit of the continuously variable transmission, Figure 5 shows the control flow, and Figure 6 shows the gear ratio and step motor rotation. It is a figure showing the relationship with a corner. 110...Step motor, 300...Control unit.

Claims (1)

[Claims] 1. In a shift control device for a continuously variable transmission in which the gear ratio is feedback-controlled so that the actual value matches a target value determined from operating conditions, for a predetermined period of time after the shift is started, A shift control device for a continuously variable transmission, comprising a correction means for instructing a preset excessive target value, which is larger in the shift direction than the target value, in place of the target value. 2. In a shift control device for a continuously variable transmission in which the gear ratio is feedback-controlled so that the actual value matches the target value determined from the operating conditions, from the start of gear shifting until the input rotational speed reaches a predetermined value. 1. A speed change control device for a continuously variable transmission, comprising a correction means for instructing a preset excessive target value, which is larger than the target value in the speed change direction, in place of the target value.