JPH0261673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a continuously variable transmission.

As a transmission for a vehicle such as an automobile or a motorcycle, a belt is hung between a driving pulley and a driven pulley so that power is transmitted by the belt, and the width of the driving pulley is Continuously variable transmissions have already been developed that automatically and steplessly change the gear ratio by changing the effective diameter of the pulley by changing it according to the driving conditions (for example, in JP-A-53
-70265, Japanese Patent Application Laid-open No. 55-65755, etc.)
Generally used.

The present invention provides a device for detecting the deceleration state of the vehicle and controlling the gear ratio based on the deceleration signal in a vehicle equipped with a continuously variable transmission as described above, thereby facilitating smooth driving and improving safety. The purpose is to measure the following, and the embodiments shown in the accompanying drawings will be explained below.

In Figures 1 and 2, reference numeral 1 denotes an input shaft that rotates with the rotation of the engine, and the input shaft 1 has a fixed pulley piece 2a and a slidable pulley piece 2b, and the groove width of the pulley is variable. A side V-pulley 2 is formed, and a fluid pressure chamber 3 for controlling the sliding movement of the pulley piece 2b is provided.

4 is an output shaft, and a fixed pulley piece 5 is attached to the output shaft 4.
An output side V-pulley 5 whose groove width is variable is formed by a pulley piece 5b which can be slid and slidably moved, and a fluid pressure chamber 6 is provided for controlling the sliding movement of the pulley piece 5b.

A V-belt 7 for power transmission is hung between the input-side V-pulley 2 and the output-side V-pulley 5, and the V-belt 7 can transmit the rotation of the input shaft 1 to the output shaft 4. By controlling the fluid to the pressure chambers 3 and 6, the effective diameters of the V-pulleys 2 and 5 are variably controlled, thereby making it possible to continuously control the gear ratio.

The fluid supplied to the fluid pressure chambers 3 and 6 is controlled by a gear ratio control valve 8 and a fluid pressure control valve 9.

That is, the gear ratio control valve 8 is interposed in the middle of the fluid passage 14 from the fluid pump 10 to the fluid pressure chamber 3 on the input side, and is connected to the signal of the throttle valve opening sensor 11 that detects the throttle valve opening of the engine and the engine. Rotation speed sensor 12
The fluid pressure control valve 9 controls the fluid pressure supplied to the fluid pressure chamber 3 according to the signal of the fluid passage 14.
The discharge fluid pressure of the pump 10 is controlled by a signal from a pulley piece position sensor 13 that is provided upstream of the speed ratio control valve 8 and detects the position of the input side pulley piece 2b and a signal from the engine speed sensor 12. It is configured like this. Reference numeral 15 denotes a fluid passage that supplies fluid from the fluid pump 10 to the output side fluid pressure chamber 6, and the discharge fluid pressure of the pump 10 is constantly acting on the output side fluid pressure chamber 6 through the fluid passage 15. Since the fluid pressure acting area of the output side fluid pressure chamber 6 is configured to be smaller than the fluid pressure acting area of the input side, the output side pulley piece 5b operates following the operation of the input side pulley piece 2b. .

In the above, when the vehicle is stopped, the fluid pressure in the input side fluid pressure chamber 3 is small, the pulley width of the input side V pulley 2 is widened, the effective diameter of the input side V pulley 2 is small, and the effective diameter of the output side V pulley 5 is small. is in a state where the gear ratio is extremely low.

The signal from the throttle valve opening sensor 11 increases as the throttle valve opening increases.
4 closes and opens the drain passage 14', the signal from the engine speed sensor 12 increases as the engine speed increases, the gear ratio control valve 8 moves in the opening direction. It has come to act in such a way that the supporting force becomes greater.

Therefore, during sudden acceleration when the throttle valve is suddenly fully opened,
The gear ratio control valve 8 keeps the supply fluid passage 14 closed and maintains the low ratio state shown in Figure 1 until the engine speed becomes considerably high, and the engine speed sensor 1
When the signal No. 2 exceeds the signal from the throttle valve opening sensor 11, the gear ratio control valve 8 opens for the first time, and the fluid discharged from the pump 10 passes through the supply fluid passage 14 to the input side fluid pressure chamber. 3, the pulley piece 2b is moved as shown by the arrow in Figure 1 to narrow the pulley width, and as a result, the hooking position of the V-belt 7 on the input side V-pulley 2 gradually moves toward the outer circumference, and the output The side V-pulley 5 moves toward the center while increasing its width, and as shown in FIG. Become. That is, during acceleration with the throttle valve fully open, the gear ratio control characteristic is shown as shown in a of FIG. 3.

During slow acceleration in which the throttle valve is gradually opened, the gear ratio control valve 8 opens at a much lower engine speed than during rapid acceleration, and the gear ratio changes from low to high, as shown in FIG. It exhibits the characteristics shown in b.

In the above-mentioned continuously variable transmission, during braking deceleration while driving at a high gear ratio, the opening of the throttle valve is at its minimum, so the engine speed becomes considerably low and the signal from the engine speed sensor 12 changes to the gear ratio. After the force urging the control valve 8 in the opening direction becomes sufficiently small, the gear ratio control valve 8 closes the supply fluid passage 14.
The system closes the drain passage 14' and opens the drain passage 14', thereby switching to the low ratio side, resulting in the characteristics shown in c in Figure 3, ensuring safe driving by allowing the engine brake to work effectively. Not only is this undesirable in terms of performance, but it also increases the load on the brake and causes problems such as increased wear and tear on brake components.

Therefore, in the present invention, a brake sensor 16 is provided to detect the brake operation state, and a signal from the brake sensor 16 operates the gear ratio control valve 8 to switch from high ratio to low ratio.
The engine speed when switching from the high ratio to the low ratio is variably controlled so that the higher the braking force, the higher the engine speed.

In this way, when braking, the gear is shifted from a high ratio to a low ratio based on a signal from a braking sensor, and the engine speed during this shift operation is variably controlled so that it becomes higher as the braking force increases. As a result, the engine speed during braking is significantly higher than in the past, and the engine brake works effectively, making driving smoother and more stable, as well as significantly reducing the burden on the brakes. It is possible.

Furthermore, by applying the above-mentioned invention to front-engine, front-drive automobiles, engine braking acts strongly on the front wheels in addition to the braking by the brake system, and the braking torque on the front wheels is greater than that on the rear wheels. This completely prevents the rear wheels from locking up and the resulting dangers such as irregular turns.

As the braking sensor 16, for example, a switch that is activated by detecting the pedal depression stroke of the brake pedal, or a brake fluid pressure switch that is activated when the brake fluid pressure supplied to the wheel cylinder exceeds a predetermined value can be used. can.

As shown in FIG. 4, the brake sensor 16 uses the hydraulic pressure of the master cylinder MC, which is activated when the brake pedal BP is depressed, that is, the master cylinder.
When using a brake fluid pressure sensor PS that detects the brake fluid pressure supplied from the MC to the wheel cylinder WC, the signal from the brake fluid pressure sensor PS is input to the control unit C as shown in Figure 5 A and B. In this way, the shift point from a high ratio to a low ratio during braking, that is, the engine braking rotational speed is variably controlled so as to increase proportionally or stepwise as the braking fluid pressure increases.

In addition, as shown in FIG. 6, a deceleration sensor 16 serves as a deceleration G sensor that detects vehicle deceleration during braking and issues a signal.
A sensor GS can also be used, the deceleration G sensor
The difference G-g between the deceleration signal G of the GS and the deceleration g that can be generated by engine braking at the engine speed at that time is determined by the control unit C, and the value of G-g is used to calculate the difference G-g in FIG. As shown in (a) or (b), it is also possible to variably control the shift point from high ratio to low ratio during braking, that is, the engine braking rotational speed, proportionally or stepwise so as to increase as G-g increases.

As described above, according to the present invention, in a vehicle using a continuously variable transmission, a brake sensor is provided to detect deceleration due to braking, and a signal from the brake sensor is used to determine whether the braking force increases as the engine speed increases. By switching the reduction ratio to the larger side at
Engine brake works effectively during braking operation,
In addition to making driving smoother and improving safety, the load on the braking device can be significantly reduced, and the life of various components of the braking device can be significantly extended. When applied to a driven vehicle, it can completely eliminate the problem of rear wheel front locking during braking, and is extremely effective, and has great practical value.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a control system of a continuously variable transmission showing an embodiment of the present invention, with FIG. 1 showing a low ratio state and FIG. 2 showing a high ratio state, respectively.
Figure 3 is a diagram showing the gear ratio control characteristics of a continuously variable transmission.
FIG. 4 is a cross-sectional explanatory diagram showing an example of the brake sensor shown in FIGS. 1 and 2, FIGS. This figure is a block diagram showing another example of the braking sensor, and FIGS. 7A and 7B are diagrams showing the control characteristics of the engine braking rotation speed by the device shown in FIG. 6, respectively. 1...Input shaft, 2...Input side V-pulley, 3...
Input side fluid pressure chamber, 4... Output shaft, 5... Output side V
Pulley, 6... Output side fluid pressure chamber, 7... V-belt, 8... Speed ratio control valve, 9... Fluid pressure control valve, 10... Fluid pump, 11... Throttle valve opening sensor, 12... ...Engine speed sensor, 1
4, 15... Supply fluid passage, 14'... Drain passage, 16... Brake sensor.

Claims (1)

[Scope of Claims] 1. An input-side V-pulley whose pulley width is variably controlled by fluid pressure is provided on the input shaft, and the pulley width is variable in accordance with changes in the pulley width of the input-side V-pulley on the output shaft. A V-pulley on the output side is provided which is controlled automatically, a V-belt is hung between both V-pulleys to transmit power, and a throttle valve is opened in the fluid passage that controls the width of the V-pulley on the input side. In vehicles using a continuously variable transmission equipped with a gear ratio control valve that is activated by signals from a speed sensor and an engine speed sensor, a brake sensor is installed that detects when braking is performed and issues a signal according to the braking force. and is configured to operate the gear ratio control valve to increase the gear ratio based on the signal from the braking sensor, and set the engine rotation speed when the gear ratio control valve operates to increase the gear ratio, A control device for a continuously variable transmission, characterized in that it is configured to variably control braking force so that it increases as the braking force increases. 2 The braking sensor is composed of a deceleration G sensor that detects vehicle deceleration during braking, and detects the deceleration that can be generated by engine braking based on the braking deceleration detected by the deceleration G sensor and the engine rotation speed at that time. The engine speed is calculated and the engine speed is variably controlled so that the engine speed at which the gear ratio control valve operates to increase the gear ratio is increased as the difference increases. A control device for a continuously variable transmission according to claim 1.