JPH0765677B2 - Controller for continuously variable transmission - Google Patents

Description

Description: (a) Field of Industrial Application The present invention relates to a control device for a continuously variable transmission.

(B) Conventional technology As a conventional control device for a continuously variable transmission, Japanese Patent Laid-Open No. 58-1808
There is one shown in No. 63. According to this, D, L, N
Select a gear change pattern according to each select position, etc., then determine a desired gear ratio command signal according to conditions such as vehicle speed and throttle opening, and based on this, control a gear change actuator such as a gear change motor. I am doing it. D
The shift pattern of the range is set such that the engine is always operated in the minimum fuel consumption rate state, and in the L range, the driving force is larger and the engine braking effect is larger than in the D range. It In the N range, the gear ratio is controlled so as to always be in the maximum gear ratio state obtained by the continuously variable transmission. This is to enable the vehicle to start at the maximum gear ratio immediately after selection when selecting a travel range such as the N range to the D range to start traveling.

(C) Problems to be Solved by the Invention However, in such a conventional control device for a continuously variable transmission,
In the N range, the control is performed so that the maximum gear ratio state is always maintained. Therefore, for example, when traveling in the D range, N
If you select the range and then return to the D range again, N
The gear ratio is in the maximum state while being selected to the range, and when returning to the D range again, the engine brake suddenly acts and a large shock accompanying this occurs, so the driving feeling is improved. It may worsen and, in some cases, cause vehicle spin and engine overrun.

In order to solve the above-mentioned problems, the applicant of the present invention discloses that, in Japanese Patent Application No. 59-87788, the same gear ratio as in the D range is applied to the N range while traveling at a vehicle speed higher than a predetermined speed. I have disclosed what was ordered. This prevents a sudden shift from occurring when a selection such as D range → N range → D range is performed, and the D-range traveling state can be smoothly restored.

However, even when the above control is performed, if the throttle opening is made larger than the fully closed state and the engine speed is increased in the state where the D range is selected to the N range, the next time the D range is selected. Since the control state of the automatic transmission does not match the engine rotation state, the clutch is engaged with a large difference in rotational speed between the input side and output side of the forward clutch, resulting in a large engagement shock. To occur. This fastening shock is not only a shock that is uncomfortable for the occupant, but also excessive torque fluctuation may cause slippage of the V-belt, which may damage the V-belt, the pulley, and the like. The present invention aims to solve such problems.

(D) Means for Solving the Problems The present invention controls the gear ratio so that the input side rotation speed and the output side rotation speed of the forward clutch are synchronized when the throttle is opened in the N range. That is, the present invention is
Rotation of the turbine of the fluid transmission device releases the engagement when the select lever is in the neutral position. It is input to the drive pulley via a clutch that changes the gear ratio of the continuously variable transmission so that a control target value is achieved. In a control device for a continuously variable transmission that controls by operating
A neutral detecting means for detecting that the select lever is in the neutral position, a throttle fully closing detecting means for detecting that the throttle is in a fully closed operating state, a means for detecting a vehicle speed, an actual engine speed or an actual turbine. When the actual rotation speed detecting means for detecting the rotation speed and the select lever are in the neutral position, the vehicle speed is equal to or higher than the predetermined value, and the throttle is fully closed, the shift pattern is kept in the D range. The lever is in the neutral position and the vehicle speed is equal to or higher than a predetermined value,
When the throttle is not in the fully closed operation state, there is provided neutral neutral shift control means for controlling the gear ratio with the actual engine rotation speed or the actual turbine rotation speed as a control target value.

(Operation) Therefore, when the select lever is in the neutral position and the throttle is fully closed, if the vehicle speed is equal to or higher than the predetermined value, the gear ratio remains in the D range. In addition, because of the same gear ratio, a sudden gear shift does not occur, and unnecessary operation of the engine brake can be prevented.

Even if the select lever is in the neutral position at a speed equal to or higher than the predetermined vehicle speed, when the throttle is opened, that is, when the engine rotation speed changes, the neutral middle speed change control means causes the actual engine rotation speed or the actual turbine speed to be changed. Since the gear ratio is controlled using the rotation speed as the control target value, the rotation speed on the output side is controlled according to the rotation speed on the input side of the clutch. Therefore, when the neutral range is selected to the D range, the clutch is engaged without fluctuation in rotation, and the D range travels smoothly without causing a shock.

(F) Embodiment FIG. 2 shows a power transmission mechanism of a continuously variable transmission. This continuously variable transmission includes a fluid coupling 12 (fluid transmission), a forward / reverse switching mechanism 15, a V-belt continuously variable transmission mechanism 29, and a differential device 56.
Etc., the rotation of the output shaft 10a of the engine 10 can be transmitted to the output shafts 66 and 68 at a predetermined gear ratio and rotation direction. This continuously variable transmission is equipped with a fluid coupling 12
(Has a lock-up oil chamber 12a, a pump impeller 12b, a turbine runner 12c, etc.), a rotary shaft 13, a drive shaft 14,
Forward / reverse switching mechanism 15, drive pulley 16 (fixed cone plate 18, drive pulley cylinder chamber 20 (chamber 20a, chamber 20b), movable cone plate
22, groove 22a, etc.), planetary gear mechanism 17 (Sun Gear 1
9, consisting of pinion gear 21, pinion gear 23, pinion carrier 25, internal gear 27, etc.), V-belt 24,
Driven pulley 26 (fixed cone plate 30, driven pulley cylinder chamber
32, movable cone plate 34, etc.), driven shaft 28, forward clutch 40, drive gear 46, idler gear 48, reverse brake 50, idler shaft 52, pinion gear 54, final gear.
44, pinion gear 58, pinion gear 60, side gear 62,
The side gear 64, the output shaft 66, the output shaft 68, and the like are included, but detailed description thereof will be omitted. Incidentally, the configuration of the part of which description is omitted is described in Japanese Patent Application No. 226706/59 filed by the present applicant. FIG. 3 shows a hydraulic control device for a continuously variable transmission. This hydraulic control device includes an oil pump 101, a line pressure regulating valve 102, and a manual valve.
104, shift control valve 106, adjusting pressure switching valve 108, shift motor (step motor) 110, shift operating mechanism 112, throttle valve 114, constant pressure pressure regulating valve 116, solenoid valve 118, coupling pressure regulating valve 120, lock-up control It has a valve 122 and the like, which are connected to each other as shown in the figure, and also have a forward clutch 40, a reverse brake 50, and a 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 shown. Detailed description of these valves and the like will be omitted.
Regarding the part of which description is omitted, the aforementioned Japanese Patent Application No. 59-226706 is used.
No. 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, port 13
4a-e, spool 136, lands 136a-b, oil passage 138, one-way orifice 139, oil passage 140, oil passage 142, one-way orifice 143, valve hole 146, ports 146a-g, spool 148, lands 148a-e. , Sleeve 150, spring 152, spring
154, pressing member 158, oil passage 164, oil passage 165, orifice 16
6, 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 18
2, land 182a-b, rack 182c, pin 183, pin 185,
Valve hole 186, ports 186a-d, oil passage 188, oil passage 189, oil passage 19
0, valve hole 192, ports 192a-g, spool 194, land 194
a to e, negative pressure diaphragm 198, orifice 199, orifice 202, orifice 203, valve hole 204, ports 204a to e,
Spool 206, land 206a-b, spring 208, oil passage 20
9, filter 211, orifice 216, 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 to h, spool 242, land 242a to e, oil passage 243, oil passage 245, orifice 246, orifice 247, orifice 24
8, orifice 249, choke type throttle valve 250, relief valve 251, choke type throttle valve 252, pressure holding valve 253, oil passage 254,
Cooler 256, cooler pressure holding valve 258, orifice 259, changeover detection switch 278.

FIG. 4 shows a shift control device 300 that controls the operation of the step motor 110 and the solenoid 224. The shift control device 300 is
Input interface 311, reference pulse generator 312, CPU
(Central processing unit) 313, ROM (Read only memory) 31
4. Has RAM (random access memory) 315 and output interface 316, which are address bus 319.
And data bus 320. This shift control device 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 cooling water temperature sensor 306, and a pattern selection switch 32.
3, the signals from the brake sensor 307 and the changeover detection switch 298 are direct or waveform shapers 308, 309 and 322, and AD.
Input through converter 310, while amplifier 317 and line 317a
Signals are output to the step motor 110 through .about.d and also to the solenoid 224, but detailed description thereof will be omitted. Incidentally, the structure of the portion whose description is omitted is described in the above-mentioned Japanese Patent Application No. 59-226706.

5 and 6 show the contents of control performed by the shift control device 300. Of these, complete engagement control and fluid coupling of the clutch by controlling the solenoid 224.
Regarding lock-up control of 12, the above-mentioned Japanese Patent Application No. 59-22
The description is omitted because it is similar to that described in No. 6706.

First, the shift position is read from the shift position switch 304 (step 502), and then it is determined whether or not the vehicle is in the traveling range, that is, the D, L or R range (step 504). If the vehicle is not in the traveling position, that is, the N range. Alternatively, in the P range, the duty ratio of the solenoid 224 is set to 0 and the lockup clutch is released (see 50
6) Next, it is determined whether or not the idle switch is on (step 507). If the idle switch is not on, that is, if the throttle is not fully closed, the current vehicle speed Vs is the predetermined vehicle speed V ₁ (for example, 10 km). / h)) (Vt> V ₁ ), and if Vs> V ₁ , the current actual turbine rotation speed Nt is set as the control target turbine rotation speed Nt _D (511). Next, based on the control target turbine rotation speed Nt _D , the target step motor pulse number P
Search _D (513). Then, step 630 of FIG.
Go to. If the throttle is fully closed at step 507, or if Vs ≦ V ₁ at step 509, the process proceeds to step 626. Since the control after step 630 and other controls are the same as those described in Japanese Patent Application No. 59-226706,
The description is omitted.

After all, the following control is performed by the control routine. That is, in the case of the D, L and R ranges, the shift pattern is searched according to each range (steps 626, 628 and 640). In the case of N or P range, there are two cases depending on the operating state. That is,
When the throttle is fully closed, or when the vehicle speed is V ₁ or less, the gear ratio retrieved based on the D range gearshift pattern is commanded. For example, if the N range is selected and the throttle is fully closed while running in the D range, the forward clutch
Since 40 is released, the vehicle is in a neutral state, but the V-belt type continuously variable transmission mechanism 29 itself is maintained in the state of the normal gear ratio in the D range, and when it is selected again in the D range, the rotation fluctuation occurs. It returns to the running state in the D range without occurring. On the other hand, when the throttle is not in the fully closed state and the vehicle speed is higher than V ₁ , the control target turbine rotation speed Nt _D
Is determined and the gear ratio is controlled based on this,
The rotation speed of the drive pulley 16, that is, the rotation speed on the output side of the forward clutch 40, is the actual rotation speed of the turbine 12c,
That is, the gear ratio is controlled so as to always match the input side rotation speed of the forward clutch 40. Therefore, when the D range is selected to the N range as in the case described above, the shift is performed so that the input side and the output side of the forward clutch 40 are always maintained in a synchronized state. When the D range is selected again in this state, the forward clutch 40 is engaged with almost no shock because the input side and the output side are rotating in synchronization. Therefore, no shock occurs and the V-belt does not slip.

When the vehicle speed Vs is V ₁ or less, the D range shift pattern is searched even in the N and P ranges, and the gear ratio becomes the maximum state. For example, when the N range is selected to the D range and the vehicle starts immediately. Will immediately start at the maximum gear ratio.

In the above embodiment, the turbine rotation speed was controlled in steps 511 and 513, but this is performed so that the input / output rotation difference of the fluid transmission is ignored and the engine rotation speed is approximately controlled. You can also

(G) Effect of the Invention As described above, according to the present invention, when the accelerator pedal is depressed while the vehicle is traveling in the N range, the actual turbine rotation speed (or the actual engine rotation speed) is set as the control target turbine. Rotation speed (or control target engine rotation speed)
As described above, since the shift control of the continuously variable transmission is performed, it is possible to prevent the clutch engagement shock when the D range is subsequently selected, improve the driving feeling, and reduce the V-belt. Can be prevented from slipping.

[Brief description of 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 device of the continuously variable transmission, and FIG. FIG. 5 is a diagram showing a shift control device of a continuously variable transmission, and FIGS. 5 and 6 are diagrams showing a control routine of the shift control device.

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Claims (1)

[Claims] 1. A control target value is realized for a gear ratio of a continuously variable transmission that is input to a drive pulley through a clutch that releases the engagement of a rotation of a turbine of a fluid transmission when a select lever is in a neutral position. In the control device for a continuously variable transmission that controls by operating the shift actuator, the neutral detection means for detecting that the select lever is in the neutral position and the throttle total for detecting that the throttle is fully closed are in operation. A closing detection means, a means for detecting the vehicle speed, an actual rotation speed detection means for detecting the actual engine rotation speed or the actual turbine rotation speed, the select lever in the neutral position and the vehicle speed is equal to or higher than a predetermined value, and When the throttle is fully closed, the gear shift pattern remains in the D range, but the select lever The vehicle speed is equal to or higher than a predetermined value in the central position,
And a control for a continuously variable transmission characterized by having a neutral medium speed change control means for controlling a speed change ratio by using an actual engine speed or an actual turbine speed as a control target value when the throttle is not fully closed. apparatus.