JPS60215150A - Shift characteristic controller for stepless transmission - Google Patents

Abstract

PURPOSE:To perform proper control over a running state, by judging the driving condition of a driver and automatically selecting it to a power or economy shift range of shift characteristics. CONSTITUTION:A solenoid valve 63 is connected to a pressure-regulating valve 61 installed in a branch oil passage 60, while a main rotation sensor 72 and a throttle opening sensor 73 both are connected to a control unit 74 controlling this solenoid valve 63, judging the driving condition of a drive, and according to this judgement, a rotary hydraulic characteristic is selected, automatically changing over to a shift characteristic conformable to the driving condition of the driver. With this constitution, since this shift characteristic is automatically selectable to a power or economy range, optimum control over a running state is performable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a belt-type continuously variable transmission in which engine rotation,
The present invention relates to a shift characteristic control device that changes the shift characteristic set by the throttle opening degree, and particularly relates to a device that determines the driving situation of a driver at regular intervals and obtains an economy-oriented or power-oriented shift characteristic adapted to the driving situation.

The main part of this type of continuously variable transmission is a pulley ratio converter consisting of a main pulley and a sub pulley with variable pulley intervals, and a drive belt wound between these pulleys. Regarding the speed change control of such a pulley ratio conversion section, there is a prior art, for example, disclosed in Japanese Patent Application Laid-Open No. 55-65755. That is, the line pressure, which is regulated in accordance with the transmission torque of each gear ratio, is always applied to the sub-pulley side. On the other hand, the spring force changed by rotating the throttle cam according to the throttle opening and the cam lift, and the pitot pressure corresponding to the rotation of the main pulley on the engine side act against the speed change control valve to control the speed change. By supplying or discharging the line pressure to the main pulley side using a valve, the winding radius of the sub pulley relative to the main pulley of the drive belt, that is, the pulley ratio or gear ratio, is changed, thereby providing stepless speed change control. There is.

By the way, the characteristics of the throttle cam according to the throttle opening degree and the characteristics of the pitot pressure according to the engine rotation are uniquely determined, so the operation of the speed change control valve based on these relationships is always constant, and the Shift characteristics for engine speed and throttle opening are fixedly set regardless of driving conditions, etc. Therefore, it is difficult to obtain appropriate speed change characteristics for differences in driving conditions between flat areas and mountainous areas. However, there were also problems in terms of fuel efficiency, etc.

In view of the problem of the fixedly set speed change characteristics of the prior art, the present invention makes it possible to change the speed change characteristics and automatically adjusts the speed change characteristics to the power or economy range that suits the driving situation of the driver. It is an object of the present invention to provide a shift characteristic control device for a continuously variable transmission that performs optimum shift control for switching and driving conditions.

For this purpose, the configuration of the present invention focuses on the fact that the shift characteristics can be changed by changing the characteristics of the pitot pressure depending on the main boolean rotation speed acting on one side of the shift control valve. It is configured to electrically generate rotary oil pressure having characteristics similar to each pitot pressure characteristic, and the power and economy ranges are set in advance in relation to the throttle opening and main pulley rotation speed, and the driver's The system determines in which range the operating conditions are at regular intervals, selects the above-mentioned rotary hydraulic characteristics accordingly, and automatically switches the shifting characteristics to those suitable for the power or economy operating conditions. This is a summary.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, a continuously variable transmission with an electromagnetic powder clutch will be described as an example of a continuously variable transmission to which the present invention is applied in FIG. Continuously variable transmission 2
can be roughly divided into forward and reverse switching section 3, pulley ratio conversion section 4,
It is composed of a final reduction section 5 and a hydraulic control section 6.

In the electromagnetic clutch 1, 13 drive members 9 each having a built-in coil 8 are connected to the crankshaft 1 from the engine.
On the other hand, a driven member 11 is integrally spline-coupled to the transmission input shaft 10 in the rotational direction, and these drives and driven members 9 and 11 are loosely fitted through a gap 12, and a powder chamber 13 is inserted into this gap 12. It is designed to collect electromagnetic particles from the ground. Mano [, Drive member 9
A slip ring 15 is installed through a holder 14, and a power feeding brush 1G is in sliding contact with the slip ring 15 to cause a clutch current to flow through the coil 8.

In this way, when a clutch current is applied to the coil 8, electromagnetic particles are combined in a chain shape and accumulated in the gap 12 between the drive and driven members 9 and 11 due to the lines of magnetic force generated between the drive and driven members 9 and 11.
Due to this coupling force, the driven member 11 slides and is integrally coupled to the drive member 9. On the other hand, when the clutch current is cut, the coupling force between the drive and driven members 9 and 11 due to the electromagnetic powder disappears, resulting in a clutch disengaged state. In this case, if the clutch current is supplied and cut in conjunction with the operation of the switching section 3 of the continuously variable transmission 2 with a shift lever, etc., the P
When switching from the (parking) or N (neutral) range to the D (drive), L (low) or R (reverse) range, the clutch 1 is automatically brought into contact, eliminating the need for clutch pedal operation.

Next, in the continuously variable transmission 2, the switching section 3 is provided between the input shaft 10 from the clutch 1 and the main shaft 17 of the continuously variable transmission 2 disposed coaxially therewith.
A reverse drive gear 18 integrally connected to the main shaft 11 and a reverse driven gear 19 rotatably fitted to the main shaft 11 are meshed with each other via a counter gear 20 and an idler gear 21, and these main shaft 17 and gears 18, 19 A switching clutch 22 is provided between the two.

Switching clutch 22 from the neutral position of P or N range
When the switching clutch 22 is engaged with the gear 18 side, the main shaft 17 is directly connected to the input shaft 10 and the forward state is in the D or L range.When the switching clutch 22 is engaged with the gear 19 side, the power of the input shaft 10 is transferred to the gear 18 or 21, the vehicle is decelerated and reversed to enter the reverse state of N range.

In the pulley ratio converter 4, a sub-shaft 23 is arranged parallel to the main shaft 17, a main pulley 24 and a sub-pulley 25 are provided on both of these axes 17 and 23, respectively, and pulleys 24 and 25 are provided.
An endless drive belt 2G runs between them.

The pulleys 24 and 25 are each divided into two parts, and the movable pulleys 24a and 25a are equipped with a hydraulic servo device 27.
．． 28 is attached to make the boob interval variable.

In this case, the main pulley 24 is fixed side pulley half rest 2
The movable pulley half 24a is moved closer to the fixed pulley body 25b to gradually narrow the pulley interval, and the sub pulley 25 is moved away from the fixed pulley body 25b to gradually increase the pulley interval. As a result, the drive belt 26 is wound around the pulleys 24 and 25 so that the ratio of diameters is changed so that continuously variable power is extracted to the subshaft 23.

In the final reduction section 5 , a large-diameter final gear 32 meshes with an output gear 31 of an output shaft 30 that is connected to the subshaft 23 via an intermediate reduction gear 29 , and a large-diameter final gear 32 meshes with an output gear 31 of an output shaft 30 that is connected to the subshaft 23 via an intermediate reduction gear 29 . Transmission is provided to the axles 34 and 35 of the left and right drive wheels.

Further, the hydraulic control unit 6 has a hydraulic pump 31 on the main pulley 24 side so as to generate hydraulic pressure during engine operation through a pump drive shaft 36 that passes through the main shaft 17 and the input shaft 10 and is directly connected to the engine crankshaft 7. provided. This pump oil pressure is controlled by the oil pressure control circuit 38 according to the throttle opening and engine rotation speed according to the depression of the accelerator, and is supplied to each of the hydraulic servo devices 27 and 28 on the main pulley and sub pulley sides via oil passages 39 and 40Q. , is configured to perform continuously variable speed control of the pulley ratio converter 4.

Regarding the speed change control system in Fig. M2, in the hydraulic nervo device 27 on the main pulley side, the movable pulley half 24a is fitted into the cylinder 27a, which also serves as a piston, and is operated by the line pressure of the servo chamber 27b. Also in the hydraulic servo device 28 on the sub-pulley side, the movable pulley half 25a is fitted into the cylinder 28a and is operated by the line pressure of the servo chamber 28b.
4a has a larger line pressure receiving area than pulley half 25a.

An oil passage 40 from the sub-pulley servo chamber 28b communicates with an oil reservoir 42 via a hydraulic pump 37 and a filter 41, and an oil passage branches from the hydraulic pump discharge side of this oil passage 40 and communicates with the main pulley servo chamber 27b. 39, pressure regulating valve 43
and a speed change control valve 44 are provided.

The speed change control valve 44 consists of a valve body '45, a spool 46, a spring 47 biased against one of the spools 46, and an actuation member 48 that changes the spring force. Hydraulic pressure corresponding to the rotational speed of the main pulley is guided through an oil passage 50, and a throttle cam 51 that rotates in accordance with the throttle opening is in contact with the operating member 48.

In addition, the boat 45b of the valve body 45 is connected to the line pressure supply port 45 by the lands 46a and 46b of the spool 4G.
The boat 45b communicates with the servo chamber 27b through the oil passage 39a of the oil passage 39, and the boat 45c communicates with the servo chamber 27b through the oil passage 39a.
b communicates with the pressure regulating valve 43 side, and the drain boat 45
d communicates with the oil reservoir side through an oil passage 52.

As a result, on the spool 46 of the speed change control valve 44, a hydraulic pressure corresponding to the main pulley rotation speed of the bow 1-45a and a spring horn corresponding to the throttle opening degree caused by the rotation of the throttle cam 51 act against each other. However, it operates based on the relationship between these two. That is, when the oil pressure increases with the engine speed, the boat 45b.

and 45c communicate with each other to supply line pressure to the main pulley valve chamber 27b to start shifting to a high speed gear. Shifting starts on the high rotation side.

Next, the pressure regulating valve 43 includes a valve body 53, a spool 54,
It consists of a spring 55 biased on one side of the spool 54, and the boat 5 on the opposite side of the spool 54.
3a and 53b respectively indicate the oil pressure of the oil passage 50 and the oil pressure of the oil passage 3.
A line pressure of 9C is introduced, and a feedback sensor 5G that engages with the movable pulley half 24a of the main pulley 24 and detects the actual gear ratio is connected to the spring 55. Further, the oil passage 39c on the pump side always communicates with the oil passage 39b on the speed change control valve side regardless of the position of the spool 54. Furthermore, the oil passage 52 on the drain side is also moved left and right by the boat 53 (which is in communication with the boat 53 (1). By controlling the communication between the line pressure boat 53c and the drain side oil passage 52, the line pressure is regulated.

As a result, the spool 54 of the pressure regulating valve 43 has an oil passage 5.
The zero oil pressure drains the line pressure and acts in a direction to lower it, whereas the force of the spring 55 according to the gear ratio determined by the feedback sensor 56 acts in a direction to increase the line pressure. In low speed gears where the transmitted torque is large, the spring 55 is biased by the feedback sensor 5'6.
Since the force is large, the line pressure is set high, and the line pressure is controlled to decrease as the gear shifts to the high speed side, and the pulley pressing force is always maintained to prevent belt slip.

In the above configuration, according to the present invention, first, an oil passage 60 that generates oil pressure according to the main pulley rotation speed branches from, for example, the oil passage 39c of the line pressure circuit, and a pressure regulating valve 60 is connected to this oil passage Go.
1. A throttle θ2 and a solenoid valve 63 for controlling exhaust pressure are sequentially provided. The pressure regulating valve 61 is connected to the spool 64.

It is composed of a spring 65 that biases one side of the line pressure and is configured to always produce a constant oil pressure by regulating the line pressure. The solenoid valve 63 is configured such that the valve body 61 opens and closes the pump port 68 in response to a signal of a predetermined duty ratio input to the coil 6G to control exhaust pressure, and extracts hydraulic pressure to the boat 69 according to the main pulley rotation speed. 69 is a speed change control valve 44;
The drain port 6 communicates with the oil passage 50 to the pressure regulating valve 43.
8 communicates with the drain side oil passage 52.

In addition, the main shaft 1 in the main boot 924 of the pulley ratio converter 4
A rotation sensor 72 consisting of a protrusion 70 and an electromagnetic pickup 71 formed around the entire circumference of the fixed-side boob body 24b, which is integral with the fixed-side boob body 24b, is provided. The rotation sensor 72 and the throttle angle signal 73 are connected to the control unit 1.
4 to the coil 66 of the solenoid valve 63.

The control unit 74 includes a processing section 75 for the output signals of each sensor 72 and 73, a judgment section 76 for determining the operating status based on both signals, and a rotational hydraulic characteristic selected based on the judgment of the judgment section 76 in accordance with the main pulley rotation speed. Output rotary oil pressure characteristic setting section 71
Furthermore, it has a duty ratio setting section 78 that determines and outputs a duty ratio according to the rotational oil pressure characteristics. Here, as shown in FIG. 3, the determination unit 76 determines in advance a predetermined suction pipe negative pressure (for example, power range Ll due to -i oommf-1g) based on the relationship between the engine shaft torque and the engine rotation speed.
When divided into economy region LE and economy region LE, it becomes as shown in Figure 13 (a), and when divided according to the relationship between throttle opening and engine speed or main pulley speed, it becomes as shown in (b), where the throttle opening is large. A power region Lp is set on the side where the main pulley rotation speed is large, and an economy region LL is set on the side where the main pulley rotation speed is large, and the decision is made with reference to a diagram dividing these Ll) and La. In addition, the setting section 17 has a characteristic curve Lp for the power range in which the rate of increase in the rotational oil pressure is small and a characteristic curve L in the economy range in which the rate of increase in the rotational oil pressure is large, as shown in FIG.
E is determined, and one of them is selected based on the result of the determination unit 76 that determines the operating status of the engine. Furthermore, calculate the ratio of Lp and [ε that drip under the operating condition for a predetermined time, index the line pressure of LD and Lε during the operating condition at the time of measurement, and multiply that line pressure by the ratio of 1p and La. Accordingly, the rotary hydraulic characteristics based on the operating conditions are obtained, and the rotary hydraulic characteristics are converted into a duty ratio by the duty setting section 78.Next, the operation of the shift characteristic control device configured as described above is explained using FIG. To explain, the determination section 76 of the control unit 74 determines the power or economy region based on the relationship shown in FIG. N in the economy area
a is incremented by 1, and N+1 is incremented by 1 in the power domain. After that, for a certain period of time NxΔt = (N
E + N9) Judge whether △ has passed or not. If not, perform the above process again. After a certain period of time has passed, each data is stored as Rp and RB, and then the above ND and Nu
Clear. Further, according to the relationship shown in Fig. 3 (C), the rotational oil pressure corresponding to the main pulley rotation speed is picked up as PE and Pp from Lε and Lp, respectively, and (Rp
pp +RhXPa)/(R1)+Ra). That is, the rotational oil pressure is determined by determining the ratio of weight to be given to either the power or economy region depending on the driving situation.

Note that when formulating the above equation, a weighting function can be used to avoid large changes in the ratio at regular intervals, and the previous ratio is taken into consideration, thereby giving continuity to the ratio. As a method, the rotational oil pressure is determined by using the ratio of Rp-αNp+<1-α)RpRε=αNε+(1-α)Rε (0<α×1) in the above equation.

The rotational oil pressure calculated as described above is applied to the duty ratio setting section 7.
8, it is converted into a decouple and the solenoid valve 63 is driven.

On the other hand, the rotational oil pressure in the power or economy range selected by judging the driving situation of the driver acts on one side of the speed change control valve 44 in opposition to a spring force corresponding to the throttle opening, and depending on the relationship between the two, the rotational oil pressure is in the power or economy range. In FIG. 5, the gear ratio is continuously changed between a low gear ratio indicated by a solid line and a high gear ratio indicated by a solid line and a minimum gear ratio. Therefore, in the power range, since the change in the rotational hydraulic characteristics of the main pulley rotation speed is small, it is difficult to shift to the high speed side, so the shift range is set to the high speed side, and the right side of the m1 and m2 areas in Figure 5 is set. This is the shift area indicated by the upward diagonal line.

On the other hand, in the economy range, the oil pressure characteristics are changed to have a large change with respect to the main pulley rotation speed, so it becomes easier to shift to a higher speed gear. Therefore, the speed change range is set from the low rotation side compared to the above, and becomes a wider speed change range than the power range as shown by the downward diagonal lines to the right of the areas m1 and m in FIG.

In this embodiment, there are two types of hydraulic characteristics, but the present invention is not limited to this. Further, the rotational oil pressure may be calculated more precisely by adding a normal region, and the suction pipe negative pressure and the intake air amount may be used instead of the throttle opening.

As is clear from the above embodiments, according to the present invention, the driving situation of the driver is judged and the speed change characteristics are automatically switched to the power or economy range, and the speed change is controlled using the speed change characteristics that match the driver's requirements. Therefore, conflicting demands such as performance and fuel efficiency can be satisfied at the same time. Since the rotary oil pressure characteristics acting on one side of the shift control valve 44 are electrically generated and changed, control is easy, and the characteristic curve of the rotary oil pressure is made proportional, making it possible to shift gears particularly at low engine speeds. Control can also be clearly exercised. Furthermore, since it is automatically switched depending on the driving situation of the driver, operability is good.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram showing an example of a continuously variable transmission to which the present invention is applied, FIG. 2 is a circuit diagram showing an embodiment of 112 according to the present invention, and FIG. Characteristic diagram,
FIG. 4 is a flowchart diagram explaining the present invention in detail;
FIG. 5 shows a transmission characteristic line according to the present invention. 2... Continuously variable transmission, G... Hydraulic control section, 39.40
... Line pressure oil path, 60... Branch oil path, 61...
Pressure regulating valve, 63... Solenoid valve, 72... Main pulley rotation sensor, 73... Throttle 11 sensor, 74
...Control unit, 7G...Driving situation judgment section, 77
...Rotary oil pressure characteristic setting section, 78...Duty ratio setting section. Figure 3 (C) j-1 Shiri C mouth stele i fat C- Funeral diagram 4

Claims (1)

[Claims] A pressure regulating valve that always produces a constant hydraulic pressure in a circuit branching from the line pressure circuit of the continuously variable transmission hydraulic control unit, and the hydraulic pressure is discharged by a duty signal to electrically control several types of rotary hydraulic pressure characteristics according to the main pulley rotation speed. Install a solenoid valve that generates
Sensors for the main pulley rotation speed, throttle opening, etc. are connected to the solenoid valve via a control unit, and the control unit determines the driving situation of the driver and selects the rotational hydraulic characteristics accordingly. A speed change characteristic control device for a continuously variable transmission, characterized in that it is configured to automatically switch to a speed change characteristic suited to driving conditions.