JPH0623033B2 - Electronic control unit for continuously variable transmission - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an electronic control device that electronically controls a line pressure by a line pressure control valve in a belt type continuously variable transmission for a vehicle.

[Prior art]

A hydraulic control system for a continuously variable transmission of this type is disclosed in, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Laid-Open No. 65755, a line pressure control valve for adjusting the line pressure acting on the belt in each pulley in accordance with the relationship between the actual gear ratio and the main pulley rotation speed, and the line pressure for the accelerator opening and the main pulley. It has a shift control valve that supplies and drains oil to the main pulley in a balanced relationship of the number of revolutions to control the shift. The role of the line pressure control valve is to apply a pulley pressing force so that the belt rotates in the main and sub pulleys without slipping and the engine output torque is surely transmitted.

[Problems to be Solved by the Invention]

Here, the output torque of the engine is determined by the relationship between the throttle opening and the engine speed. By the way, as described above, the factors that control the line pressure by the line pressure control valve are the gear ratio and the main pulley rotation speed. Therefore, the engine output torque is not equal to the engine rotation speed when the clutch is engaged, and the main pulley rotation speed is It is only given as a function of numbers. Therefore, when the pulley ratio is constant, the line pressure is determined only by the main pulley rotation speed. Therefore, the line pressure control valve can always transmit the maximum torque at each main pulley rotation speed. The line pressure is set to the maximum. For this reason, when the torque at a certain main pulley rotation speed is low, the line pressure becomes unnecessarily high (useless) and the load of the oil pump increases, resulting in deterioration of fuel consumption. Therefore, it is desired to control the line pressure by the line pressure control valve in accordance with not only the engine speed but also the output torque of the engine.
The one disclosed in Japanese Patent Publication No. 7-161347 has been proposed. On the other hand, conventionally, as for a continuously variable transmission, for example, JP-A-54
Electronic controls such as those disclosed in JP-A-6-46153 and JP-A-57-90450 have been proposed. However, in the above-mentioned prior art, the gear ratio control is performed in the minimum fuel consumption state, paying attention to the advantage of continuously variable transmission, and the line pressure control is not mentioned. In view of such circumstances, the present invention optimally controls the line pressure for applying the pulley pressing force in relation to the engine output torque to reduce the load on the oil pump, and an electronic control device for a continuously variable transmission. The purpose is to provide.

[Means for Solving the Problems]

In order to achieve this object, the present invention provides a line pressure control valve in a hydraulic control unit of a continuously variable transmission, and a solenoid valve whose discharge pressure is controlled by an electric signal in a hydraulic system which generates a control hydraulic pressure of the line pressure control valve. And a control device for outputting a control signal to the solenoid valve, wherein the control device includes a throttle opening, an engine speed,
An engine output torque detecting means for detecting the engine torque by inputting each detection signal of the engine speed and the throttle opening, which has a detecting means for respectively detecting the rotating speeds of the main pulley and the auxiliary pulley, and an engine speed. And the main pulley rotation speed detection signals, if both rotation speeds match, it is judged that the clutch is engaged, and if they do not match, clutch engagement judging means is judged to be clutch released, and the clutch engagement judgment. When the clutch is released, a control signal of the line pressure capable of transmitting the maximum torque by the pressure determining means is output to the solenoid valve while the clutch engagement signal is input. When the state is judged, the relation between the torque detected by the engine output torque detecting means, the constant detected from the gear ratio and the effective pitch radius of the main pulley is determined. It is characterized in that a control signal of the line pressure calculated on the basis of the value detected by the operator is output to the solenoid.

[Action]

According to the above configuration, the clutch engagement determining means and the pressure determining means are interposed in the element in which the line pressure is controlled by the line pressure control valve. The line pressure is set so that maximum torque can be transmitted when the clutch is released, such as during idling, so that the required pulley pressing force is applied so that belt slip does not occur during subsequent acceleration. On the other hand, after the clutch is engaged during running, the line pressure is
By setting the line pressure calculated based on the engine output torque, the constant detected from the gear ratio, and the value detected in relation to the main pulley effective pitch radius, the line pressure becomes unnecessarily high. Therefore, it is possible to prevent the increase in the load of the oil pump, and to suppress the unnecessary increase of the load of the oil pump, thereby preventing the deterioration of the fuel consumption.

【Example】

An embodiment of the present invention will be specifically described below with reference to the drawings. First, referring to FIG. 1, as an example of a continuously variable transmission to which the present invention is applied, a continuously variable transmission with an electromagnetic powder clutch will be described. Reference numeral 1 is an electromagnetic powder clutch, 2 is a continuously variable transmission, and The gear transmission 2 is roughly composed of a forward / reverse switching unit 3, a pulley ratio conversion unit 4, a final reduction unit 5, and a hydraulic control unit 6. In the electromagnetic powder clutch 1, a drive member 9 having a coil 8 therein is integrally connected to a crank shaft 7 from the engine, while a driven member 11 is integrally spline-connected in a rotational direction to a transmission input shaft 10. These drives and driven members 9 and 11 are loosely fitted through the gap 12,
Electromagnetic powder is accumulated in the gap 12 from the powder chamber 13. Further, a slip ring 15 is installed on the drive member 9 via a holder 14, and the slip ring 15
A brush 16 for power supply is in sliding contact with the coil 8 so that a clutch current flows through the coil 8. In this way, when a clutch current is applied to the coil 8, the magnetic powder generated between the drive and the driven members 9 and 11 causes the electromagnetic powder to be combined in a chain shape in the gap 12 between the two, and the magnetic powder is integrated to the drive member 9. On the other hand, the driven member 11 is slid and integrally connected and connected.
On the other hand, when the clutch current is cut off, the coupling force between the drive and the driven members 9 and 11 due to the electromagnetic powder disappears and the clutch is disengaged. If the clutch current is supplied and cut in this case in conjunction with the operation of the switching unit 3 of the continuously variable transmission 2 with a shift lever or the like, the P (parking) or N (neutral) range can be achieved. The clutch 1 is automatically engaged or disengaged when switching from the D to the D (drive) or R (reverse) range, and the clutch pedal operation becomes unnecessary. Next, in the continuously variable transmission 2, the switching portion 3 is provided between the input shaft 10 from the clutch 1 and the main shaft 17 arranged coaxially therewith, and the reverse drive gear integrally coupled to the input shaft 10 is provided. The counter gear 20 and the idler gear are a reverse driven gear 19 that is rotatably fitted to the main shaft 17.
21 through meshing, and further these main shaft 17 and gear
A switching clutch 22 is provided between 18,19. Then, when the switching clutch 22 is engaged with the gear 18 side from the neutral position of the P or N range, the main shaft 17 is directly connected to the input shaft 10 and D or L.
When the shift clutch 22 is engaged with the gear 19 side in the range forward state, the power of the input shaft 10 is decelerated and reversed by the gears 18 to 21 to set the R range in the backward state. In the pulley ratio conversion unit 4, a sub shaft 23 is arranged in parallel with the main shaft 17, a main pulley 24 and a sub pulley 25 are provided on both shafts 17 and 23, respectively, and an endless structure is provided between the pulleys 24 and 25. The drive belt 26 is stretched around. The pulleys 24 and 25 are both divided into two parts, and hydraulic servo devices 27 and 28 are attached to the movable pulley halves 24a and 25a to make the pulley interval variable. In this case, in the main pulley 24, the movable pulley half 24a is brought closer to the fixed pulley half 24b to gradually reduce the pulley interval, and the sub pulley 25 is, on the contrary, movable to the fixed pulley half 25b. The pulley halves 25a are moved away from each other and the pulley intervals are gradually increased.
The ratio of the winding diameter in 5 is changed to take out the power without speed change to the auxiliary shaft 23. The final reduction unit 5 has a large-diameter final gear connected to an output gear 31 of an output shaft 30 connected to the auxiliary shaft 23 via an intermediate reduction gear 29.
32 meshes with each other, and is transmitted from the final gear 32 to the axles 34, 35 of the left and right drive wheels via the differential mechanism 33. Further, the hydraulic control unit 6 has an oil pump 37, which is provided on the main pulley 24 side so as to constantly generate hydraulic pressure during engine operation by a pump drive shaft 36 which penetrates the main shaft 17 and the input shaft 10 and is directly connected to the engine crankshaft 7. Is provided. The pump hydraulic pressure is controlled by the hydraulic control circuit 38 by the gear ratio, the throttle opening degree according to the depression of the accelerator, the engine speed, etc., and the hydraulic servo devices 27 on the main pulley side and the sub-pulley side via the oil passages 39, 40. , 28, and is configured to perform continuous shift control of the pulley ratio conversion unit 4. The shift control system of the hydraulic control unit 6 will be described with reference to FIG. 2. In the hydraulic servo device 27 on the main pulley side, the movable pulley half 24a is fitted to the cylinder 27a also as the piston, and the line pressure of the servo chamber 27b is used. In the hydraulic servo device 28 on the auxiliary pulley side, the movable pulley half 25a is fitted in the cylinder 28a and is operated by the line pressure in the servo chamber 28b. In this case, the pulley half 24a is operated. Has a larger line pressure receiving area than the pulley half 25a. Then, the oil passage 4 from the sub-pulley servo chamber 28b
0 communicates with the oil sump 42 via the oil pump 37 and the filter 41, and branches from the oil pump discharge side of the oil passage 40 to the oil passage 39 communicating with the main pulley servo chamber 27b.
0 and a gear ratio control valve 44 are provided. The gear ratio control valve 44 includes a valve body 45, a spool 46, and a spool 46.
The spring 47 of the spool 46 comprises a spring 47 biased to one side and an actuating member 48 for changing the spring force.
The pitot pressure from a rotation sensor 49 provided on the main pulley side for detecting the engine speed is guided to a port 45a on the opposite side via an oil passage 50, and the operating member 48 rotates depending on the throttle opening. The moving throttle cam 51 is in contact. Further, the port 45b of the valve body 45 is the land 46a, 46b of the spool 46.
To selectively communicate with one of the line pressure supply port 45c and the drain port 45d, and the port 45b communicates with the servo chamber 27b through the oil passage 39a of the oil passage 39.
c communicates with the line pressure control valve 60 side through the oil passage 39b. As a result, in the spool 46 of the gear ratio control valve 44,
The pitot pressure corresponding to the engine speed of the port 45a and the spring force corresponding to the throttle opening degree accompanying the rotation of the throttle cam 51 act in opposition to each other, and the relationship between the two acts. That is, when the pitot pressure rises with the engine speed, the ports 45b and 45c communicate with each other to supply a line pressure to the main pulley servo chamber 27b to start shifting to the high speed side, and at this time, the spring 47 depending on the throttle opening degree. The greater the force of, the more the shift start point shifts to the higher speed side of the engine speed. The line pressure control valve 60 includes a valve body 61, a spool 62, ports 61a and 61b communicating with the pump-side oil passage 39c, a drain port 61c,
It has a control port 61d, and the pump discharge hydraulic pressure of the port 61b and the control hydraulic pressure of the port 61d act on the spool 62 in opposition. When the pump discharge hydraulic pressure is constant, the spool 62 is moved by the control hydraulic pressure, and the line pressure is controlled by adjusting the opening between the ports 61a and 61c. Further, as a hydraulic system for generating the control hydraulic pressure of the line pressure control valve 60, for example, a drain port 61 of the line pressure control valve 60 is used.
The oil passage 63 from c communicates with the pressure regulating valve 64 that constantly generates a constant hydraulic pressure. An oil passage 65 from the pressure regulating valve 64 communicates with a solenoid valve 66 that controls the exhaust pressure by an electric signal, and an oil passage 67 for controlling hydraulic pressure from the solenoid valve 66 communicates with a port 61d of the line pressure control valve 60. . Further, as an electric control system for controlling the solenoid valve 66, engine rotation sensors 70 on the engine side, throttle opening sensors 71, rotation sensors 72, 73 installed on the main pulley 24 and the sub-pulley 25 to detect their rotation speeds. Have. The signals of these sensors are input to the control device 74, and the duty signal for line pressure control output from the control device 74 is given to the solenoid valve 66. Here, the theory of the sub-pulley pressing force by the line pressure P will be described. It is expressed by the following equation in relation to the gear ratio i, the friction coefficient μ, the pulley angle β, and the belt winding angle. When i max ≧ i ≧ 1, P = [ζ + {η / [e × p (ξ ×) −1]}] × (T / R) = К (T / R) When 1 ≧ i ≧ i min , P = ζ (T / R) = К ′ (T / R) where ζ = (1/2) · (cos β / μ), η = (1/2) cot β, ξ = μ / sin β Is. From this, it is understood that the line pressure P is obtained by a constant K or K ′ in each of the two gear ratio regions, the engine output torque T, and the main pulley effective pitch radius R. Based on this, the configuration of the control device 74 will be described with reference to FIG. 3. It has an engine output torque detecting means 75 to which signals of the engine speed and the throttle opening of the engine rotation sensor 70 and the throttle opening sensor 71 are inputted. In the fourth
The torque T is detected using the map shown in FIG. The engine rotation signal N _E and the main pulley rotation signal Np from the main pulley rotation sensor 72 are input to the clutch engagement determination means 76,
When both rotations match, it is determined that the clutch is engaged.
The main pulley rotation signal Np and the sub-pulley rotation signal Ns from the sub-pulley rotation sensor 73 are input to the gear ratio calculating means 77, where the gear ratio i (Np / Ns) is calculated, and this output signal is a constant and radius detection. Input to the means 78. On the other hand, the relationship between the constants K and K ′ for the gear ratio i and the main pulley effective pitch radius R is shown in the maps shown in FIGS. 4 (b) and (c). Detected in. The output signals of the engine torque detecting means 75 and the constant / radius detecting means 78 are input to the line pressure calculating means 79, where P =
The required line pressure is obtained by calculating K (T / R) and P = K '(T / R), and this output signal is input to the pressure determining means 80. This means 80 includes the clutch engagement determination means 76.
Is also input, the pressure is determined based on the output of the control device 74 when the clutch is engaged, and the pressure at which the maximum torque can be transmitted is set when the clutch is released. This is converted into a duty signal and output. . Next, the operation of the apparatus thus configured will be described. First, the overall operation will be described.
The solenoid valve 66 controls the exhaust pressure by, for example, a duty signal from 74, and the line pressure control hydraulic pressure generated in the solenoid valve 66 is input to the line pressure control valve 60 via the oil passage 67 to control the line pressure. , Is always introduced into the sub-pulley servo chamber 28b. On the other hand, in the gear ratio control valve 44,
The spool 46 is driven to balance the pitot pressure with the spring force according to the throttle opening, and the gear ratio control valve
The line pressure is supplied to or discharged from the main pulley servo chamber 27b by means of 44, whereby the ratio of the belt winding diameters of the main pulley 24 and the sub pulley 25 is converted, and the line ratio between the maximum gear ratio and the minimum gear ratio is changed. Continuously shift. Therefore, the operation of the line pressure control will be described with reference to the flowchart of FIG. 5. The control device 74 includes the sensors 70, 71, 72, 7
The signal from 3 is input. Therefore, when the clutch engagement determination means 76 determines that the clutch is released due to the mismatch between the engine speed and the main pulley rotation speed, the pressure determination means 80 sets the line pressure at which the maximum torque can be transmitted. The smallest signal is input to solenoid valve 66. Therefore, the highest control oil pressure is input from the solenoid valve 66 to the line pressure control valve 60 to limit the drain thereof, whereby the line pressure is set to the highest value. On the other hand, when the engine speed and the main pulley speed match and the clutch engagement determining means 76 determines that the clutch is engaged, the torque T detected by the engine torque detecting means 75,
The duty signal is output based on the constant based on the gear ratio i, the constant detected by the radius detecting means 78 or K ′, and the line pressure P calculated by the line pressure calculating means 79 based on the value of the main pulley effective pitch radius R. . Therefore, the line pressure by the line pressure control valve 60 along with the control oil pressure by the solenoid valve 66 is
It is controlled based on the above calculation. Although one embodiment of the present invention has been described above, the gear ratio control valve can also be electronically controlled in the same manner as the line pressure control, and can also be applied to a system in which the line pressure is directly controlled by an electric signal.

【The invention's effect】

As is apparent from the above description, according to the electronic control device for a continuously variable transmission of the present invention, the clutch engagement determination means and the pressure determination means are interposed in the element whose line pressure is controlled by the line pressure control valve. And ... The line pressure is set so that maximum torque can be transmitted when the clutch is released, such as during idling, so that the required pulley pressing force is applied so that belt slip does not occur during subsequent acceleration. On the other hand, after the clutch is engaged during running, the line pressure is
By setting the line pressure calculated based on the engine output torque, the constant detected from the gear ratio, and the value detected in relation to the main pulley effective pitch radius, the line pressure becomes unnecessarily high. Therefore, it is possible to prevent the deterioration of fuel consumption by suppressing unnecessary increase of the oil pump load. By simply rewriting the map, it is possible to easily realize a continuously variable transmission combined with various engines.

[Brief description of drawings]

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 the device according to the present invention, and FIG. 3 is a line pressure control system of a control device. Block diagrams shown in FIGS. 4 (a) to 4 (c) are characteristic diagrams, and FIG. 5 is a flow chart for explaining the operation of the present invention. 4 ... Continuously variable transmission, 24 ... Main pulley, 25 ... Sub pulley,
26 …… Belt, 44 …… Gear ratio control valve, 60 …… Line pressure control valve, 66 …… Solenoid valve, 70 …… Engine rotation sensor, 71 …… Throttle opening sensor, 72 …… Main pulley rotation sensor, 73 ... Sub pulley rotation sensor, 74 ... Control device.

Claims (1)

[Claims] 1. A hydraulic control unit for a continuously variable transmission, comprising a line pressure control valve, a solenoid valve for controlling the exhaust pressure by an electric signal in a hydraulic system for generating a control hydraulic pressure of the line pressure control valve, and the solenoid valve. A control device for outputting a control signal, wherein the control device includes a throttle opening, an engine speed,
An engine output torque detecting means for detecting the engine torque by inputting each detection signal of the engine speed and the throttle opening, which has a detecting means for respectively detecting the rotating speeds of the main pulley and the auxiliary pulley, and an engine speed. And the main pulley rotation speed detection signals, if both rotation speeds match, it is judged that the clutch is engaged, and if they do not match, clutch engagement judging means is judged to be clutch released, and the clutch engagement judgment. When the clutch is released, a control signal of the line pressure capable of transmitting the maximum torque by the pressure determining means is output to the solenoid valve while the clutch engagement signal is input. When the state is judged, the relation between the torque detected by the engine output torque detecting means, the constant detected from the gear ratio and the effective pitch radius of the main pulley is determined. An electronic control device for a continuously variable transmission, characterized in that a control signal of a line pressure calculated based on a value detected by a control unit is output to a solenoid.