JPS60104855A - Control device of continuously variable transmission - Google Patents

Abstract

PURPOSE:To obtain arbitrary engine rotation-car velocity characteristic by providing a modulator for adjusting a load signal fluid which varies with an engine load according to the torque transmission ratio and inputting a signal from the modulator to a ratio control valve. CONSTITUTION:There is provided a modulator 14 for adjusting a load signal fluid which varies with an engine load according to the torque transmission ratio, and an auxiliary signal fluid generated from the modulator 14 is applied to a ratio control valve 10 in such a manner as to enlarge the torque transmission ratio. Thus, a signal system can be controlled without any influence of a power system to obtain arbitrary engine rotation-car velocity characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device that variably controls the torque transmission ratio between input and output shafts in a continuously variable transmission.

(Prior art) Currently, as a transmission, 'O! 2. Description of the Related Art Mechanical transmissions that use several gear trains to change the torque transmission ratio between input and output shafts in stages according to the gear ratio are often used.

In this case, since the l/lux transmission ratio changes stepwise, there is a drawback that the torque transmission ratio cannot be selected arbitrarily.For this reason, continuously variable transmissions that can change the torque transmission ratio steplessly have been used. There are various ideas.

For example, one example of a hydraulic continuously variable transmission is I-I S'I'' (hydrostatic transmission), which combines a hydraulic motor and a hydraulic pump.
An example of a mechanical continuously variable transmission is a belt type continuously variable transmission in which the average effective diameter of input and output pulleys is changed in a belt type transmission.

Consider the case where such a continuously variable transmission is not available, for example, when used in a vehicle. Normally, driving control of a vehicle is performed using the accelerator pedal, brake pedal, clutch pedal, etc., and vehicle speed control is performed only by operating the accelerator pedal, except for deceleration, so even if a continuously variable transmission is used for a vehicle. It is desirable to change the torque transmission ratio (that is, the reduction ratio) as appropriate in accordance with the operation of the accelerator pedal. In response to these demands, the torque transmission ratio of the continuously variable transmission has been changed to
Various methods have been proposed for variable control depending on the throttle opening degree of /.

For example, as disclosed in Japanese Patent Application Laid-open No. 56-6°6553, torque transmission of the belt is possible by changing the V bell 1 and groove width of the primary pulley and secondary pulley of the belt type transmission mechanism by a hydraulic actuator. In a V-belt continuously variable transmission that variably controls the ratio, the V-belt groove width of the primary pulley is changed according to the rotation of the primary pulley and the throttle opening, and information corresponding to this groove width is transmitted to the control pulp of the secondary pulley. to control the torque transmission ratio by controlling the groove width of the secondary pulley appropriately.
A similar method has been proposed. In this case, the larger the throttle opening, the larger the torque transmission ratio, and the larger the rotation of the primary pulley, the larger the torque transmission ratio is set, and the relationship between engine rotation and vehicle speed is as shown in FIG. When the groove width of the primary pulley is determined by the rotation of the primary pulley and the throttle opening, the characteristics shown by the solid line ζ in FIG. 1 can be obtained. In the figure, Ll has the maximum torque transmission ratio (at this time L
2 indicates the time when the torque transmission ratio is at its minimum (the peak gh range at this time).For example, if the throttle is suddenly opened to full throttle, the engine speed will change. The vehicle speed increases by f5 on the line Lx until it reaches a predetermined value N1, and then the engine rotation remains constant (N1 rotations) and the torque transmission ratio gradually decreases to increase the vehicle speed. When such control is performed, the vehicle speed increases while the engine rotation remains constant, and there is a problem in that the driver does not feel much acceleration, unlike the conventional driving sensation. Therefore, in the case of the above proposal, the operating pressure of the hydraulic actuator that determines the groove width of the secondary goo is applied as a control signal for the primary pulley, and as shown by the broken line in Fig. 1,
The torque transmission ratio decreases as the engine speed increases, increasing the vehicle speed by 1" to provide a sense of acceleration.Furthermore, in the case of the broken line, even if the vehicle speed is the same, the vehicle speed increases by 1". , the engine speed may be lower than in the case of the solid line, and the fuel efficiency should be improved.

In this way, when changing the torque transmission ratio of a continuously variable transmission, the engine rotation must be changed, that is, the first
It is preferable to control as shown by the broken line in the figure. However, in the case of the above proposal (Japanese Unexamined Patent Publication No. 56-66553),
The actuator pressure of the secondary pulley plays the role of maintaining the belt tension appropriately, and the torque transmission ratio is variably controlled depending on this actuator pressure.
There is a problem in that the slope of the broken line in the diagram cannot be freely set. In other words, in the case of the above proposal, a part of the power system is used in the signal system that controls the power system such as the actuator that actually operates to change the l/lux transmission ratio, so the engine There is a problem in that the degree of freedom in setting the vehicle speed characteristics with respect to rotation is small, and so-called design flexibility is lost.

(Object of the Invention) In view of such problems, the present invention provides control of a continuously variable transmission that allows control to be performed without being influenced by the signal system and the power system, and allows arbitrary engine rotation-vehicle speed characteristics to be obtained. The purpose is to provide a device.

(Structure of the Invention) The control device for a continuously variable transmission of the present invention is configured to steplessly change the torque transmission ratio from the input shaft to the output shaft of the continuously variable transmission using a fluid actuator, and A continuously variable transmission that adjusts the supply of working fluid to a hydraulic actuator using a ratio control valve that is activated when a signal fluid is applied to indicate the state, and that variably controls the torque transmission ratio according to the driving state of the vehicle. In the control device, the load signal fluid that changes depending on the engine load is adjusted according to the torque transmission ratio using a modulator to create an auxiliary signal fluid, and this auxiliary signal fluid is sent to the ratio control valve to increase the torque transmission ratio. It is characterized by having a wobble in addition to the direction.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a hydraulic circuit diagram showing one embodiment of the control device of the present invention, and here shows an example in which a belt type continuously variable transmission is used.

The primary pulley 1 consists of a fixed flange 1a fixed on the input shaft, and a sliding flange 1b facing the fixed flange la IIC and slidable on the input shaft, and the sliding flange 1b is a fluid actuator. It is slid in the axial direction by the primary cylinder 2vc. The secondary pulley 3 includes a fixed flange 3a fixed on the output shaft, and a sliding flange 3 facing the fixed flange 3a and slidable on the output shaft.
b, and the sliding flange 3b is slid in the axial direction by a secondary cylinder 4, which is a fluid actuator. A belt 20 is stretched between the primary pulley 1 and the secondary pulley 3, and the rotation of the primary pulley 1 (input shaft rotation) is transmitted to the secondary pulley 3 (output shaft) V via the belt 20. At this time, both pulleys 1,
■The effective radius of belt 20 in 3 is primary shilling 2
and changes depending on the operation of the secondary cylinder 4. That is, by controlling the hydraulic pressure supplied to both cylinders 2.degree. 4, it is possible to change the effective radius of both pulleys 1 and 3 of the belt 20 and to change the torque transmission ratio steplessly.

To explain the control of the hydraulic pressure supplied to both cylinders 2 and 4, first, the hydraulic pump filter sucks oil in the sump 5,
Line 4. Hydraulic pressure is supplied to the secondary cylinder 4° secondary pulley control valve and ratio detection valve 11 through a, 6a and 11a'. Secondary IJ
The IJ control valve 7 regulates this oil pressure, and the operating pressure of the secondary cylinder 4 is maintained at an appropriate level.

The ratio detection valve 11 is interlocked with the sliding flange 3b of the secondary pulley 3, and by <-12, a pushing force is applied according to the movement of the sliding flange 31), and the hydraulic pressure corresponding to this pushing force is discharged. It is generated on the side lines 11b, llc.

Since the rotation radius of the VELSIT 200 is determined by the movement of the sliding flange 3b, the movement of the sliding flange 3b corresponds to the torque transmission ratio, and therefore the oil pressure of the lines 1ib and ilc is the oil pressure corresponding to the torque transmission ratio.

On the other hand, the oil discharged from the secondary pulley control valve 7 passes through a line 739 and enters the primary pulley control valve, where the oil pressure supplied to the primary cylinder 2 via the line 2a is controlled. Since the primary pulley control valve 8 is located downstream of the secondary pulley control valve 7, the oil pressure supplied to the primary cylinder 2 must be lower than the oil pressure supplied to the secondary cylinder 4 in order to operate both pulps independently. Therefore, the pressure receiving surface fJf of the primary cylinder 2 is made larger than the pressure receiving area of the secondary cylinder 4 to balance the forces acting on the sliding flanges i, b, 31) of both pulleys 1 and 3.

On the other hand, there are lines], Oa and 10b between the primary pulley control valve 8 and the secondary pulley control valve 70.
A ratio control valve 10 is provided which communicates with both the valves 8 and 7 via the valve, and controls the ratio of the control hydraulic pressure of both valves. When the control oil pressure of both pulps, that is, the ratio of the working oil pressure of the primary cylinder 2 and the working oil pressure of the secondary cylinder 4, is changed, the sliding flange lb of both pulleys changes.
, 3bK The force that acts on one side is thicker (and the other side is smaller, and the effective radius of the belt 20 on both pulleys 1 and 3 is changed and the torque transmission ratio changes. In other words, the torque transmission ratio is changed by the ratio control valve 10vrC. It is the one that controls the ratio control pulse.If you change the pressure of the secondary pulley control valve 70, the ratio control pulse 7'lO
Since the oil pressure ratios of the K upper horizontal lines 2a and iia are kept constant, the oil pressures of the lines 2a and 4a both rise and fall, allowing the tension of the bell 20 to be changed. That is, the secondary boolean control valve 7 controls the tension of the V-bell 20.

On the other hand, the pitot tube 9 detects the dynamic pressure in the oil gutter 1cK provided on the side of the fixed flange of the primary pulley 1.
Hydraulic pressure (governor pressure Pc) according to the rotation of primary pulley 1
) are obtained on lines 9a and 9b. Line 9a is connected to secondary pulley control valve 7. In addition to this, the secondary pulley control valve 7 includes a line 11b from the ratio detection valve 11, and a line that receives oil pressure supply from the throttle valve 13, which generates oil pressure (throttle pressure PT) according to the opening degree of the throttle. 13a are connected, and the rotational speed of primary pulley 1, torque transmission ratio, t6 and throttle opening (engine load) V
■Adjust the tension of the heald 20 according to C. Line 9b is also connected to ratio control valve 10, which is supplied with throttle pressure PT from throttle valve 13 through line 13b and hydraulic pressure (module 1/pressure PM) from modulator 14. ) are connected to the hydraulic lines 14a, and the ratio control valve 1o is operated by hydraulic pressure supplied from these lines. Specifically, as the rotation of the primary pulley 1 increases, the torque transmission ratio decreases, and as the throttle opening increases, the torque transmission ratio increases, and the influence of the throttle opening is partially offset by the hydraulic pressure from the modulator 14. Correction. This operation will be explained with reference to FIGS. 3 to 7.

FIG. 3 is a cross-sectional view showing the modulator 14, in which a spool 25 which can freely slide in the left and right directions in the figure is inserted into the modulator head 21, and a grab 22 whose right side is fixed by a snap ring 23. The spool 25 is urged to the left by the spool 1 non-circuit 24. The left end of the spool 25 is a pressure receiving surface; @AR is the reciprocating pressure from the line 11C (1) R (that is, the hydraulic pressure according to the torque transmission from the ratio detection valve 11)
On the right side of the missing valve, where the diameter of the IJ ball has increased in steps, the pressure receiving area AT receives the throttle pressure Pr (i.e., the oil from the throttle valve 13) from the valve 1'J', The right side of the spool 25 receives the biasing force 1 of the spring 24, and also receives the modulated pressure l) M from the line 13c in the pressure receiving part 7 AM.The modulated pressure PM increases here, and the spool 25 moves to the left side. When pushed, the vortex 252 of the spool 25 causes the line 13d to
The line 14a is connected, and hydraulic PM is supplied to the line 14b side to push the spool 25 back. Further, when the throttle pressure PT increases and the spool 25 is pushed to the right, the line 14a and the EVE-JEST EX are connected and the oil pressure PR decreases and the spool 25 is returned. That is, when the oil pressure and the spooling force are balanced, the relationship F-AR@, PR~l-AT-PrPM- is established.

M At this time, the ratio pressure PR is adjusted by the ratio detection valve IIK as shown in FIG.

In other words, at maximum torque transmission (Low range), P
When R is at its maximum and torque transmission is at its minimum (Ilight range), PR is at its minimum and changes almost linearly during this time. As shown in FIG. 5, the throttle pressure PT is adjusted so that it is minimum when the throttle is fully closed, maximum when the throttle is fully open, and changes almost linearly therebetween. Therefore, as shown in Fig. 6, the modulated pressure PM increases linearly as the torque transmission ratio decreases, and increases as the throttle opening increases, and can be expressed by a group of straight lines such as the solid line. You can do it. This modulated pressure PM 71) Niregio control valve 10
Therefore, as shown by the solid line in FIG. 7, as the torque transmission ratio increases, the engine rotational speed also increases. The broken lines in Figures 6 and 7 show the characteristics when the modulation pressure is not changed. In this case, the torque transmission ratio is small if the engine continues to rotate after reaching the specified rotation. This means that it will be accelerated.

As shown in FIG. 6, when the throttle pressure PT is small due to the biasing force of the spring 24, the modulation pressure PM is zero when the torque transmission ratio is large, and the modulation pressure PM does not change until the torque transmission ratio becomes small. Takumi has been set so that PM increases. For this reason, when the throttle pressure PT is small, that is, when the throttle opening is small, the gear shift should not be started from a point where the engine rotation is too low. For this reason, when the throttle opening is small and the engine speed is low, increase the rotation to near the maximum at that throttle opening, increase the output as much as possible, and then reduce the torque transmission ratio to increase speed. , the engine output can be used effectively, and on the other hand, the feeling of acceleration becomes a problem in places where the throttle opening is wide (and the engine speed increases), so it is necessary to change the torque transmission ratio and the engine speed to improve the sense of acceleration. The aim is to improve fuel efficiency.

In addition, the pressure receiving area An of the spool 25 of the modulator 14
, AT, AM and the supporting force F of the spring 25, the rate of change of the torque transmission ratio corresponding to engine rotation can be set arbitrarily, and the acceleration performance can be set arbitrarily. At the same time, even if you change this setting, ratio control valve 1
The adjustment of the torque transmission rate at 0 and the V-belt tension setting at the secondary goo control valve 7 are not disturbed.

In this embodiment, the governor pressure Pa applied to the valve 7 and IOK may be a hydraulic pressure that changes depending on the vehicle speed.

(Effects of the Invention) As explained above, according to the present invention, in high-load areas during work/engine where acceleration is required, the torque (r4 ratio) is changed as the engine rotates to reduce the acceleration sensation. It also has the advantage of reduced fuel consumption, and since the power system and signal system are independent, the rate of change in the torque transmission ratio as the engine rotates can be set arbitrarily, making it easy to meet various demands. can.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the relationship between engine rotation and vehicle speed of a vehicle using a conventional continuously variable transmission, Fig. 2 is a hydraulic circuit diagram showing one embodiment of the control device of the present invention, and Fig. 3 is a cross-sectional view of a modulator used in the control device 171 of the present invention, and FIGS. 4 to 7 are graphs showing various relationships in the control device of the present invention, and FIG. The relationship between ratio pressure and torque transmission ratio. Figure 5 shows the relationship between throttle pressure and throttle opening due to the throttle valve. Figure 6 shows the relationship between modulator pressure and torque transmission ratio due to the modulator. Figure 7 shows the relationship between engine rotation and vehicle speed. The relationships between the two are shown. 1...Primary pulley 2...
...Bridging cylinder 3...Secondary pulley 4...Secondary cylinder 7...Secondary tool control g1 valve 8...Primary force fl
t11fL11 Valve 10... Ratio control valve 11... Ratio detection valve 13...
...Throttle valve 14...Modulator Fig. 3 Fig. 4 Fig. 5 (LOWJ Itc shift, I] -y) It, M
14gI46 Figure O efjen rotation,

Claims (1)

[Claims of Claims] A continuously variable transmission mechanism that transmits power between input and output shafts and continuously changes the torque transmission ratio from the input shaft to the output shaft, and a fluid type that changes the torque transmission ratio of this continuously variable transmission mechanism. an actuator;
It consists of a ratio control valve that adjusts the supply of working fluid to this hydraulic actuator, and a driving signal fluid indicating the driving condition of the vehicle is added to the ratio control valve, and the torque transmission ratio is varied according to the driving condition of the vehicle. In the continuously variable transmission to be controlled, a modulator is provided that adjusts a load signal fluid that changes depending on the engine load according to the torque transmission ratio, and an auxiliary signal fluid generated by the modulator is sent to the ratio control valve Vζ and Increase the torque transmission ratio (
A control device for a continuously variable transmission, characterized in that the direction (C) is added.