JPH01116364A - Control device for v-belt type continuously variable transmission - Google Patents

Abstract

PURPOSE:To carry out speed change to a high speed side and avoid a speed change shock at the time of failure while traveling at a high speed by making a first control valve for controlling a driving side pulley generate the maximum oil pressure while a second control valve of controlling a driven side pulley generate the minimum oil pressure at the time of the OFF of an input signal. CONSTITUTION:When an engine speed Nin is less than a cranking rotating speed, an electronic control device 60 sends a signal of zero duty ratio to a speed change control valve 43 and a load thrust control valve 45, and feeds the maximum oil pressure to the speed change ratio controlling oil chamber 16 of a driving side pulley 12 while feeding the minimum oil pressure to the load thrust controlling oil chamber 17 of a driven side pulley 14, to improve a starting property as the maximum speed change ratio. Then, as traveling is started by turning on a starting control valve 47, both control valves 43, 45 are controlled at a defined duty ratio in accordance with the traveling condition to obtain a desired speed change ratio. In this case, if the solenoids 44, 46 of the control valves 43, 45 or the signal system thereof fail and are turned off while traveling at a high speed, speed change is always carried out to a high speed ratio side. Thereby, a speed change shock can be avoided.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a control device for a V-belt type continuously variable transmission, in particular, an oil chamber for thrust control is provided on both the drive side pulley and the driven side pulley, and both oil chambers are provided with oil chambers for thrust control. The first . The present invention relates to a control device for a V-belt continuously variable transmission provided with a second control valve.

[Prior art and its problems]

Conventionally, as a control device for a V-belt type continuously variable transmission, as described in Japanese Patent Laid-Open No. 193936/1982, an oil chamber for thrust control is provided on both the driving pulley or the driven side boolean, and both oil chambers are provided on both sides. It is known to be provided with control valves for respectively controlling the hydraulic pressure supplied to the chambers and electromagnetic valves for respectively generating signal hydraulic pressures acting on the control valves.

In the case of the above control device, the configurations of the control valve and solenoid valve for controlling the respective hydraulic pressures of the driving pulley and the driven pulley are the same, and the solenoid valve is, for example, a normally closed type (closed when not energized). If a solenoid valve is used, the signal oil pressure of the solenoid valve will be maximum when the current is not energized, and the output oil pressure of the control valve will be the minimum (drain). However, with the above configuration, the solenoid valve for controlling the drive side pulley will be Or if the signal system breaks down,
Since the signal oil pressure of this electromagnetic valve is the maximum and the output oil pressure of the control valve is the minimum, the oil pressure supplied to the drive-side pulley decreases rapidly, and as a result, there is a possibility that a shock may occur due to a sudden downshift.

For example, if the solenoid valve for hydraulic control on the drive side pulley is a normally open type (dispersion type when not energized) and the solenoid valve for hydraulic control on the driven pulley is a normally closed type, this problem can be solved during high-speed driving. Even if the solenoid valve for controlling the driving pulley or its signal system fails, the speed will always be shifted to the high speed ratio (High) side, so this problem can be solved.

However, with the above configuration, the following problem occurs when it is difficult to start the engine, such as when the engine is cold. In other words, even if the starter is activated by the ignition switch, if the engine has not started yet, the solenoid valves are both turned off in consideration of the battery charging and discharging balance.
It is customary to hold it in the state. On the other hand, since the engine is forcibly rotated by the starter, the oil pump also rotates, and hydraulic pressure is supplied to each pulley control valve.

At this time, all solenoid valves are OFF, so the signal hydraulic pressure of the normally open solenoid valve for controlling the drive pulley is at its minimum.
The output oil pressure of the control valve becomes maximum, the signal oil pressure of the normally closed solenoid valve for controlling the - side driven side boob becomes maximum, the output oil pressure of the control valve becomes minimum, and the V-belt continuously variable transmission reaches minimum speed change. The gear will be shifted to the ratio (High) side. The inertia of a V-belt continuously variable transmission increases in proportion to the square of the gear ratio, so as the gear ratio is shifted towards the minimum gear ratio, the engine load increases rapidly, making it more difficult to start the engine and draining the battery. This results in

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems.The purpose of the present invention is to avoid shift shock even if the solenoid valve or its signal system fails during high-speed driving, and to avoid shift shock toward the minimum gear ratio when starting the engine. An object of the present invention is to provide a control device for a V-belt continuously variable transmission that can prevent gear changes and improve engine startability.

[Structure of the invention]

In order to achieve the above object, the control device of the present invention provides a thrust control oil chamber in both the driving pulley and the driven pulley, and a second oil chamber having a solenoid for respectively controlling the oil pressure supplied to both oil chambers. 1. In a control device for a V-belt continuously variable transmission equipped with a second control valve, the first control valve for hydraulic control of the drive side boob is designed to output the maximum hydraulic pressure when an OFF signal is input to its solenoid. The second control valve for oil pressure control of the driven side boob is configured such that the solenoid is connected to an O
It is configured to output the minimum oil pressure when the FF signal is input, and when the engine is started, if the engine rotation speed is less than the minimum rotation speed at which the engine can start, the first oil pressure is output. Second
OFF signals are input to both solenoids of the control valves, and when the number of revolutions exceeds the minimum rotation speed, the first. The present invention is characterized in that a control signal for maintaining the maximum gear ratio is input to each solenoid of the second control valve.

That is, when the first control valve is de-energized, the output oil pressure is maximum,
Since the output oil pressure of the second control valve is at its minimum when it is not energized, even if the solenoid valve or its signal system fails during high-speed running, the gear ratio can always be shifted to the high-speed ratio side. Additionally, when the engine speed is less than the minimum speed at which the engine can start (this degree is called the cranking speed), an OFF signal is input to both the solenoids of the first and second control valves, so the engine is turned off. Battery consumption can be prevented in the unstarted state. -Furthermore, if the number of revolutions exceeds the cranking speed, the number 1. Since a control signal for maintaining the maximum gear ratio is input to each solenoid of the second control valve, it is possible to prevent the gear ratio from shifting toward a high speed ratio when starting the engine, improving engine startability. can.

[Explanation of Examples]

FIG. 1 shows a schematic structure of a V-belt type continuously variable transmission according to the present invention. A crankshaft 2 of an engine 1 is connected to an input shaft 5 via a flywheel 3 and a damper mechanism 4. An external gear 6 is fixed to the end of the input shaft 5.
This external gear 6 meshes with an internal gear 7 fixed to a drive shaft 11 of a continuously variable transmission 10 to decelerate the power of the input shaft 5 and transmit it to the drive shaft 11.

The continuously variable transmission IO is composed of a driving side boot 2 provided on a driving shaft 11, a driven side pulley 14 provided on a driven shaft 13, and a V-belt 15 wound between both pulleys. The drive pulley 12 has a fixed sheave 12a and a movable sheave 12b.
A gear ratio control oil chamber 16 for controlling the gear ratio is provided behind the movable sheave 12b. On the other hand, the driven pulley 14 also has a fixed sheave 14a and a movable sheave 14b, similar to the drive side pulley 2. Behind the movable sheave 14b, the load thrust necessary for torque transmission is transferred to the V-belt 15. An oil chamber 17 for controlling the load thrust is provided. The oil pressure supplied to the gear ratio control oil chamber 16 and the load thrust control oil chamber 17 is controlled by a gear change control valve 43 and a load thrust control valve 45, which will be described later.

A hollow shaft 19 is rotatably supported on the outer periphery of the driven shaft 13, and the driven shaft 13 and the hollow shaft 19 are connected and connected by a starting clutch 20 consisting of a wet multi-plate tarlatch.The hydraulic pressure of the starting clutch 20 will be described later. It is controlled by a start control valve 47. A forward gear 21 and a reverse gear 22 are rotatably supported on the hollow shaft 19, and a forward/reverse switching dog clutch 23 connects either the forward gear 21 or the reverse gear 22 to the hollow shaft 19. It is designed to be connected. A reverse idler gear 25 that meshes with the reverse gear 22 and another reverse idler gear 26 are fixed to the reverse idler shaft 24. Further, a counter gear 28 that meshes with the forward gear 21 and the reverse idler gear 26 at the same time, and a final reduction gear 29 are fixed to the counter shaft 27, and the final reduction gear 29 meshes with the ring gear 31 of the differential device 30. , power output shaft 3
2.

The pressure regulating valve 40 regulates the hydraulic pressure discharged from the oil reservoir 41 by the oil pump 42, and supplies it as line pressure to the speed change control valve 43.
, is output to the load thrust control valve 45 and the start control valve 47. The speed change control valve 43, the load thrust control valve 45, and the start control valve 47 are operated by the solenoid 44.
46 and 48 are operated to regulate the line pressure and output control oil pressure to the oil chambers 16 and 17 and the starting clutch 20, respectively. Therefore, only the control signals from the electronic control device 60 to the solenoids 44, 46, and 48 control the speed ratio of the continuously variable transmission 10, the belt tension, and the starting clutch 20.
The torque transmission capacity can be freely controlled.

Among the above control valves 43, 45, 47, load thrust control valve 4
5 and the start control valve 47 are of the normally closed type, whereas the shift control valve 43 is of the normally open type. In other words, the control valve is 45°47
The output oil pressure is the minimum when the input signal to the solenoid 46 and 48 is OFF, and the output oil pressure is the maximum when the input signal is ON, whereas the output oil pressure is the maximum when the input signal to the solenoid 44 is OFF, and the input oil pressure is the maximum when the input signal to the solenoid 44 is OFF. When the signal is ON, the output oil pressure is at its minimum. The shift control valve 43 is configured as a normally open type and the load thrust control valve 45 is configured as a normally open type in this way. ), but drive side boo 1
This is to supply a high oil pressure to the oil chamber 16 of the second pulley 14 and a low oil pressure to the oil chamber 17 of the driven pulley 14, thereby shifting to a high-speed ratio side and avoiding sluggishness caused by a sudden downshift.

Note that the control valves 43, 45, and 47 may be configured, for example, by a combination of a solenoid valve that generates a signal oil pressure and a pressure regulating valve that outputs oil pressure according to the signal oil pressure, or alternatively, a solenoid valve. It may be composed of a single solenoid valve such as
In any case, the control valve 45.47 is connected to the solenoid 46.
The control valve 43 may be of any type as long as it can output a hydraulic pressure proportional to the signal input to the solenoid 48, and the control valve 43 can output a hydraulic pressure inversely proportional to the signal input to the solenoid 44.

FIG. 2 shows a structural diagram of the electronic control device 60, in which 61
is the engine rotation speed N! *A sensor that detects (the rotation speed of the input shaft 5), 62 a sensor that detects the vehicle speed V (the rotation speed of the output shaft 32), and 63 a sensor that detects the rotation speed of the driven shaft 13 (the input rotation speed of the starting clutch 20 or Sensors 64 are P and R for detecting the rotation speed of the driven side boolean IJ14.

A sensor 65 detects the N, D, and L shift positions, and a sensor 65 detects the throttle opening.
~64 signals are input to the input interface 66,
The signal from the sensor 65 is converted into a digital signal by an A/D converter 67. 68 is a central processing unit (CPU), 69
is a read-only memory (R
OM), 70 is a random access memory (RAM) that temporarily stores signals and parameters sent from each sensor.
), 71 are output interfaces, and these CP
U68, ROM69, RAM70, output interface 71, input interface 66 and A/D converter 6
7 are interconnected by a bus 72. The output of the output interface 71 is outputted as a control signal to each solenoid 44, 46, 48 via the output dry buffer 3.

Next, the operation of the control device of the present invention will be explained with reference to FIG.

First, when the control starts, the engine speed Ni is compared with the cranking speed N,1 (minimum speed at which the engine can start) (80), and if Nta<N-t, the engine has not started yet. Solenoid 44,
46 and 48 are turned off (81).

This prevents solenoid power consumption before starting the engine and improves battery charging and discharging balance *Nts≧
In the case of N□, follow the driven wheel rotation speed N, □ and vehicle speed V (
absolute value of the difference (IN,, t −
The value obtained by dividing v l ) by the driven wheel rotation speed N ov L is compared with a constant value ε (82).

If N, ll&, it means that the relative rotation difference before and after the starting clutch 20 is small, in other words, the starting control is in a state where it should be completed, so in this case, the starting control solenoid 4
8 (duty ratio 100%) (83), engages the starting clutch 20, and shifts to shift control (84).
,,On the other hand, No,.

If so, the start control is not yet in a state where it should be completed.
The shift control solenoid 44 is turned on, the load thrust control solenoid 46 is turned on or duty-controlled, and the start control solenoid 48 is duty-controlled so that the start clutch 20 generates the desired transmission torque (85). The gear shift bag WIO is maintained at the maximum gear ratio (Lov), and the start control continues.

When the ignition switch is switched from the OFF position to the start position, the engine is forcibly rotated by the starter, so the oil pump also rotates and oil pressure is supplied to each control valve 43, 45, 47. At this time, if the engine speed N ie is less than the cranking speed N,2, the oil pump discharge pressure is very low, and even if the solenoids 44, 46, 48 are kept in the OFF state, they are not always open. The oil pressure supplied to the oil chamber 16 of the drive pulley 12 via the mold control valve 43 is also low, and can be maintained at the lowest speed ratio (Low). On the other hand, engine speed N! When fi exceeds the cranking rotation speed N□, the oil pump discharge pressure increases,
If each of the solenoids 44 and 46 is maintained in the OFF state, the oil pressure supplied to the oil chamber 16 of the drive side boot 2 through the normally open control valve 43 will also increase, and there is a risk that the gear will be shifted to the high speed ratio side. be. Therefore, in the present invention, when the engine speed N0 becomes equal to or higher than the cranking speed N0, the solenoid 44
．． A control signal for maintaining the maximum gear ratio is input to 46, that is, an ON (duty ratio 1002) signal is input to the solenoid 44, and an ON or digital signal is input to the solenoid 46 to lower the output oil pressure of the gear change control valve 43 and reduce the load. The output oil pressure of the thrust control valve 45 is increased. Thereby, the maximum gear ratio is reliably maintained and the inertia of the continuously variable transmission 10 is minimized, so that the startability of the engine can be improved.

In the above embodiment, an oil chamber for speed ratio control is provided on the driving pulley, and an oil chamber for load thrust control is provided on the driven pulley, but the present invention can also be applied to a reverse configuration. Of course, it is possible to apply

[Effects of the Invention] As is clear from the above description, according to the present invention, the first control valve that controls the driving pulley generates the maximum hydraulic pressure when the input signal is OFF, and the second control valve that controls the driven pulley generates the maximum hydraulic pressure. generates the minimum oil pressure when the input signal is OFF, so even if the solenoid valve or its signal system fails during high-speed driving, the gear will always be shifted to the high-speed ratio side, thereby avoiding shift shock.

Also, if the engine speed is less than the cranking speed, the first. Since the OFF signal is input to both the solenoids of the second control valve, the charging/discharging balance of the battery can be improved, and when the rotation speed exceeds the cranking speed, the solenoid of the first and second control valves is input with the OFF signal to maintain the maximum gear ratio. Since a control signal is input, it is possible to prevent the gear from shifting toward the minimum gear ratio when starting the engine, thereby improving engine startability.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an example of a belt-type continuously variable transmission according to the present invention, FIG. 2 is a configuration diagram of an electronic control device, and FIG. 3 is a flowchart showing the operation of the present invention. 1...Engine, lO...Continuously variable transmission, 12...
・Drive side pulley, 14... Driven side pulley, 15...
■Belt, 16... Oil chamber for speed ratio control, 17... Oil chamber for load thrust control, 43... Speed change control valve, 44...
Solenoid for speed change control, 45...Load thrust control valve, 4
6... Solenoid for load thrust control, 60... Electronic control device. Figure 1 Figure 2

Claims (1)

[Scope of Claims] Thrust control oil chambers are provided in both the driving pulley and the driven pulley, and first and second control valves each having a solenoid for controlling the oil pressure supplied to both oil chambers are provided. In a control device for a V-belt type continuously variable transmission, the first control valve for hydraulic control of the driving pulley is configured to output the maximum hydraulic pressure when an OFF signal is input to the solenoid, and controls the hydraulic pressure of the driven pulley. The second control valve for
It is configured to output the minimum oil pressure when an OFF signal is input to the solenoid, and when the engine speed is less than the minimum speed at which the engine can start, the solenoids of the first and second control valves are activated. A V-belt type continuously variable transmission characterized in that an OFF signal is input to both of them, and a control signal for maintaining the maximum gear ratio is input to the solenoids of the first and second control valves when the rotation speed is above the above-mentioned minimum rotation speed. control device.