JPS60237255A - Hydraulic pressure control device for automatic speed changer - Google Patents

Abstract

PURPOSE:To control properly and highly accurately the period of time of under-lap upon switching the running sub speed changer of the automatic speed changer, in which the sub speed changer is attached to the output side of a main speed changer, from high-speed stage into low-speed stage. CONSTITUTION:An indicated speed changing stage detecting means 150 detects the indicated speed changing stage Sx of the main speed changer 14. The operating means 152 of a predetermined time Ta operates suction throttle opening degree theta, oil temperature T, vehicle speed V and the predetermined time Ta when the operating position of the sub speed changer 16 is changed from H to L. A timer 154 measures an elapsed time Ti from the change of H L, a solenoid valve control means 158 maintains the solenoid valve 102 for controlling the under-lap ON from the time Ti to the time Ta while the same valve 102 is turned OFF after the time Ta has elapsed. Thus, a shock caused upon switching from the high-speed stage into the low-speed stage may be mitigated and the overrunning of the engine may be avoided.

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to a hydraulic divider for manually switching an auxiliary transmission from a high gear to a low gear. BACKGROUND ART In order to improve driving performance, there is an automatic transmission that is equipped with an auxiliary transmission that can be manually switched between a high speed gear and a low speed gear. In order to obtain an appropriate increase in engine speed by avoiding shift impact and excessive engine speed caused by switching the auxiliary transmission from a high gear to a low gear while driving,
It is necessary to control the underlap period, that is, the period during which the high-speed frictional engagement device of the auxiliary transmission is in the released state and the low-speed frictional engagement device remains in the released state. In addition, in automatic transmissions in which the auxiliary transmission is provided on the output side of the main transmission, the inertia mass of the main transmission differs depending on the gear position of the main transmission, and therefore the engine rotational speed during the underlap period differs. Since the rising speed of is different,
During the underlap period, not only the vehicle speed (the higher the vehicle speed, the greater the amount of increase in engine rotational speed required at the time of switching);
It is also necessary to switch according to the gear position of the main transmission. Japanese Patent Publication No. 58-25177 does not deal with hydraulic control when manually operating an auxiliary transmission from a high gear to a low gear, but it deals with hydraulic control related to vehicle speed when automatically shifting from a high gear to a low gear. Controls are disclosed. In other words, a plurality of spool valve-type control valves are provided that receive the hydraulic pressure of the low-speed frictional engagement device and the high-speed frictional engagement device as control pressure, and these multiple control valves control the low-speed frictional engagement device. When the oil pressure rises to a predetermined level that causes the friction engagement device for the low speed gear to slip, the oil pressure of the friction engagement device for the high speed gear is reduced to a value that causes the friction engagement device for the high speed gear to slip. ,
The amount of this reduction is based on the vehicle speed and throttle opening,
Further, when the oil pressure of the high-speed expropriation frictional engagement device drops to a predetermined level that substantially releases the high-speed M frictional engagement device,
The oil pressure of the low speed friction engagement device is increased to a value that substantially engages the low speed friction engagement device. However, the hydraulic control disclosed in Japanese Patent Publication No. 58=-25177 is for downshifting by automatic gear shifting, and cannot be applied immediately to manual switching from a high gear to a low gear in the auxiliary transmission, and there is also a period of overturning. In other words, it discloses control over a period in which both the low-speed gear frictional engagement device and the high-speed frictional engagement device are maintained in a cloudy engaged state.Furthermore, the spool valve type control valve has a complicated structure. , control accuracy is low due to temporal variations in the transmission of control pressure to the control valves, variations in the spring force of the control valves, and the overlap period due to oil temperature. Object of the Invention The object of the present invention is to provide an automatic transmission in which the auxiliary transmission is attached to the output side of the main transmission, and to improve the ungrabbing period when the auxiliary transmission changes from a high gear to a low gear while the vehicle is running. An object of the present invention is to provide a hydraulic control device that can appropriately and accurately control the hydraulic pressure and has a simple configuration. Means for Achieving the Object In order to achieve this object, the present invention provides an auxiliary transmission connected to the output side of a main transmission having a plurality of gears and capable of manually switching between a high gear and a low gear. Equipped with a transmission
In the hydraulic control system of an automatic transmission, it is held in an engaged state to reach the high gear of the auxiliary transmission. A friction engagement device for a high speed gear that is held in an engaged state to achieve a low gear of the auxiliary transmission; A switching valve that connects each engagement device to a hydraulic medium supply oil path to switch the auxiliary transmission from a high gear to a low gear, a solenoid valve that restricts the supply of hydraulic medium to the low gear friction engagement device, and a switching valve. A time measuring means for measuring the time elapsed since the valve was switched from a high gear position to a low gear position, a gear position detecting means for detecting a gear position of a main transmission, a vehicle speed sensor for detecting vehicle speed, a gear position. A time tf' calculation means for calculating a predetermined time related to the detection value of the detection means and the vehicle speed sensor, and a low speed friction coefficient until the elapsed time measured by the time measurement means reaches the time calculated by the time calculation means. and a solenoid valve control means for controlling the solenoid valve by an electric signal so that the supply of hydraulic medium to the coupling device is restricted. According to the invention, the predetermined time calculated by the time calculation means is also related to the intake throttle opening and the temperature of the hydraulic medium. Effect: When the switching valve does not switch from the position corresponding to the high gear to the position corresponding to the low gear due to manual operation by the driver, the high gear friction engagement device of the auxiliary transmission is connected to the drain and its hydraulic pressure is The frictional engagement device for high-speed gears begins to fall, and finally the high-speed frictional engagement device is released.Even after the switching valve is switched, the frictional engagement device for high-speed gears is dependent on the gear position of the main transmission, the vehicle speed, as well as the intake throttle opening and oil temperature. During a predetermined period of time, the supply of hydraulic medium is restricted by a solenoid valve, and even after the high-speed frictional engagement device is released, the disengaged state is maintained, resulting in an ungrabbing period. After this predetermined time has elapsed, the restriction on the supply of hydraulic medium to the low-speed friction engagement device by the solenoid valve is lifted, and the low-speed friction engagement device is supplied with hydraulic medium and quickly enters the engaged state. , the auxiliary transmission shifts to a low gear. During the ungrabbing period of an appropriate length, the engine rotational speed quickly increases to an appropriate value according to the gear position of the main transmission and the vehicle speed. Effects of the Invention In the present invention, the ungrabbing period has a length corresponding to the gear position of the main transmission, and the engine rotation speed increases by an appropriate amount according to the gear position of the main transmission during the ungrabbing period. It is possible to reduce the impact when switching from a high gear to a low gear, and to avoid excessive revving of the engine. Since the ungrabbing period is controlled by controlling a solenoid valve using an electric signal, the configuration is much simpler than that of a spool valve type hydraulic control device. Furthermore, since the acid dip period of the present invention is not affected by temporal variations in transmission of control hydraulic pressure and variations in spring force of the control valve, high control precision can be obtained. Furthermore, the predetermined time period for controlling the supply of hydraulic medium to the low-speed frictional engagement device by the electromagnetic valve is also a function of the throttle opening of the engine. When the throttle opening is low, the time required for the engine to rev up is longer, so the predetermined time is increased, and when the throttle opening is high, the time required for the engine to rev up is shorter, so the predetermined time is increased. By reducing the time, it is possible to compensate for the worsening of the shift shock. In a preferred embodiment, the electromagnetic valve is a valve that opens and closes an oil path that connects an oil path for hydraulic medium from the switching valve to the low-speed frictional engagement device to the drain. Preferably, the predetermined time period during which the supply of hydraulic medium to the low-speed frictional engagement device by the solenoid valve is restricted is also a function of the temperature of the hydraulic medium. When the hydraulic medium is at a low temperature, the viscosity of the hydraulic medium is high, and the flow speed of the hydraulic medium in the oil passage decreases, causing the release and engagement timing of the M friction locking device to shift. By relating it to temperature, such deviations can be compensated for. The present invention will be described in detail with reference to the drawings. FIG. 1 shows an overall configuration diagram of an automatic transmission, and shows the engine 10. It includes a fluid torque converter 12, a leaf transmission 14 having a plurality of gears, and a sub-transmission 16. Sub-transmission 1
6 is an input shaft coupled to the output element of the main transmission 14 +
8. A planetary gear set 20 including a sun gear coupled to the input shaft 18, an output shaft 22'' coupled to the carrier of the planet gear set 20, and controlling the connection between the input shaft 18 and the carrier of the planet gear set 2°. It has a high-speed clutch 24 that controls fixing of the ring gear of the planetary gear set 20, and a low-speed brake 26 that controls fixing of the ring gear of the planetary gear unit 20.When the high-speed clutch 24 is engaged, the rotation of the input shaft 18 is outputted at a reduction ratio of 1. The signal is transmitted to the input shaft 22, and the input shaft 18 is
The rotation is decelerated and transmitted to the output shaft 22. The throttle opening sensor 28 detects the throttle opening of the intake passage, the pattern select switch 30 detects the driving pattern selected by the driver such as economy (economic driving), power (outgoing driving), etc. 32 detects a shift position such as D (drive) or R (reverse) selected by the driver, and an L-H position switch 34 detects a shift position such as L (low gear) or H of the sub-transmission 16 selected by the driver. (high speed gear) position, the oil temperature sensor 4o detects the temperature of oil as a hydraulic medium used in the hydraulic control device 42, the oil pressure sensor 44 detects the oil pressure of the high speed clutch 24, and the vehicle speed sensor 46
detects the rotational speed of the output shaft 22, which is proportional to the vehicle speed. C
The PU 48 continuously receives signals from these sensors and switches, and controls the hydraulic control device 42 based on these signals. FIG. 2 shows the hydraulic control device 42 of FIG. 1 in detail, and the oil pump 50 sucks oil in the oil pan 52, pressurizes it, and discharges it. The main shift control circuit 54 includes well-known elements such as a shift valve and a primary regulator valve that change the gear stage of the main transmission 14, and the primary regulator valve is connected to a line pressure oil passage 56 as a supply pressure oil passage when the throttle opening is 0. Related line pressure P
generate l.

[The 2H switching valve 60 is connected to the boats 62, 64 and the drain 66 connected to the line pressure oil passage 56.
．． 72, and other baud) -68,70;
Boat or drain 62 in relation to L-H position
, 64, 66.613, and 70.72. The L-H switching valve 6o may be supplied with a control pressure in relation to the L-H position and may have a spool that moves in relation to this control pressure. The high speed clutch 24 is held in an engaged state at the H position, and the oil passage 76
is now connected to boat 68. The accumulator 78 is connected to the oil passage 76, and in the middle of the oil passage 76, an orifice 80 and a reverse valve 82 are provided parallel to each other 9u. The check valve 82 opens when the oil in the high speed clutch 24 flows toward the boat 68. Low speed brake 2
6 is held in a locked state at the L position and is connected to the boat 70 via an oil passage 86. Accumulator 8
8 is connected to an oil passage 86, and an orifice 90 and a check valve 92 are provided in parallel with each other in the middle of the oil passage 86. The check valve 92 opens when the oil of the low speed brake 26 flows toward the boat 70. The discharge oil passage 100 branches from the oil passage 86 between the boat 70 and the orifice 90, and guides the oil at the branch point to the drain. The solenoid valve 102 as a solenoid valve has a solenoid 104 and a valve body 106 that opens and closes the discharge oil path 100 in relation to the solenoid 104, and similarly to the main speed change control circuit 54, the solenoid valve 102 has a CP
Controlled by electrical signals from IJ 48. The control performed by CPo 48 will now be described with reference to FIG. In FIG. 3, Pc is the servo oil pressure of the high speed clutch 24, and Pb is the servo oil pressure of the low speed brake 26. Before time tl, the ■ and H positions are at the H (high speed stage) position, and the boat 68 is connected to the boat 62 and the boat 70 is connected to the drain 72 at the L-H switching valve 60, respectively. As a result, the high speed clutch 24 is supplied with oil from the line pressure oil passage 56 and held in the engaged state, while the oil in the low speed brake 26 is discharged and the low speed brake 26 is released. to the state. Retained. Therefore, the sub-transmission 16 is in the high speed gear. At time t1, the L-H position is switched from the H position to the L position by the driver. With this switching, L-Hg
The control pressure of the J switching valve 60 is changed by the CPU 48, and the spool of the L-H switching valve 60 is switched from a high speed position to a low speed position. In this way, the boat 68 is connected to the drain 66, the boat 70 is connected to the boat 64, and the servo oil pressure Pc begins to fall. On the other hand, the boat 70 receives oil from the line pressure M156, but since the solenoid valve 102 still opens the discharge oil passage 100 within the predetermined time Ta from time t1, the servo oil pressure Pb is maintained at zero, and the low speed The engagement of the stage brake 26 is prevented. At time t2, when a predetermined time Ta has elapsed from time t1, solenoid valve 102 closes discharge oil passage 100. As a result, the servo oil pressure Pb starts to rise from time t2 and reaches a predetermined oil pressure at time t3 after time Tb has elapsed from time t2, and the low gear brake 26 becomes half-engaged. The period from when the servo oil pressure Pc appropriately decreases until time t3 is an underlap period in which both the high speed clutch 24 and the low speed brake 26 are in a disengaged state, and the deep rotational speed increases smoothly during this underlap period. . FIG. 4 shows the characteristics of the predetermined time Ta. As the vehicle speed (2) increases, the amount of increase in engine rotational speed required when switching from the H position to the H position increases, so the predetermined time Ta for lengthening the tail wrap period also increases. In addition, the required increase amount of the inertial mass and engine rotational speed of the main transmission R14 is related to the first to fourth gears of the main transmission 14, so the predetermined time Ta is It is also set as a function of the gear position. Note that in FIG. 4, the predetermined time Ta is shorter in the third gear than in the fourth gear because the third gear is the reduction ratio l″c
This is because when the speed is in overdrive, the inertial mass at the third speed is smaller than that at the fourth speed. Furthermore, as the oil temperature T decreases, the viscosity of the oil increases and the oil supply speed to the low speed brake 26 decreases, so the predetermined time Ta becomes a shorter value as the oil temperature T decreases. It is possible to compensate for the shift in the acid wrap period due to the oil temperature T by setting the temperature T. Furthermore, as the throttle opening degree θ increases, the engine speed increases, so the predetermined time Ta is
As the throttle opening becomes higher, the value can be set to a shorter value to compensate for the shift in the underlap period due to the zero throttle opening. FIG. 5 is a flowchart of a speed change control routine according to the control explained in FIG. A flag F1 indicating that the operating position of the sub-transmission 16 has been switched from H to H and a timer that counts the elapsed time TL from the time when the flag F changes from 0 to 1 are reset as initialization (step +10). , 112). The commanded gear Sx of the main transmission 14 is calculated based on the vehicle speed ■, the intake throttle opening degree 0, etc. (step 114), and the drive control (on, off) of the solenoid valve for the main transmission is performed according to the commanded gear Sx. This is done (step 116), and the gear position of the main transmission 14 is set to the commanded gear position Sx. Further, drive control of the sub-transmission solenoid valve is performed according to the H and L operating positions of the sub-transmission 16 (step +18), and the L-H switching valve 60 is placed in a position corresponding to the operating position. If there is no change in the operating position from 11 to 11 (the judgment in step 120 is F-0, the judgment in step 122 returns to the calculation of the indicated gear 5x of the NO8 main transmission (step 114), but the operation position is When changes from H to L (determination at step +22 is YES), flag F is set (step +24),
The count of the elapsed time TI by the timer is disclosed (step 126), and then the vehicle speed v1 indicated gear Sx and the oil temperature T
1 and intake throttle opening θ are read (step 1
28.130.132+ 134), these v +
A predetermined time Ta is calculated based on Sx + T 16 (step 136). Next, compare the elapsed time Ti and the predetermined time Ta (step 138), Ti < T
If a, that is, the predetermined time Ta after the change from H→L
If T
If i≧Ta, that is, after the predetermined time Ta has elapsed, the underlap control solenoid valve 1Ω2 is turned off to close the discharge oil passage 100 (step 142), and the flag F is reset (step 14.1). . FIG. 6 is a functional block diagram of the present invention. The indicated gear position detecting means 150 detects the indicated gear position Sx of the main transmission [4], that is, the actual gear position. When the operation position of the sub-transmission 16 changes from H to L, the predetermined time Ta calculation means 152 calculates the intake throttle opening degree θ,
A predetermined time Ta is calculated based on the oil temperature T1, the vehicle speed V, and the commanded gear position Sx. The timer 154 measures the elapsed time T] since the change from H to L, and the comparing means +56 compares T1 and Ta. Solenoid valve control means 158
keeps the underlap control solenoid valve +02 on until Ti reaches Ta, and after Ta has elapsed, underlap control solenoid valve +02 is turned on.
Turn off the knob control solenoid valve 102. Incidentally, the time t1 that is the starting point of the predetermined time Ta is! ,・Since the L-H position signal of the H position sensor 30 has changed from H to L, the position of the L-H switching valve 60 can be detected from the output of a sensor that can actually detect the position, or the oil pressure sensor 4.
This can be detected from the drop in the servo oil pressure Pc detected by 4. In the embodiment, the solenoid valve 102 is provided in the discharge oil passage 100, but it may be of a type that limits the supply of oil to the low speed brake 26 by opening and closing the oil passage 86. Although the present invention has been described with reference to embodiments, it will be apparent to those skilled in the art that the present invention can be practiced in various ways without departing from the spirit of the invention.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram of the automatic transmission, Figure 2 is a detailed diagram of the hydraulic control device in Figure 1, Figure 3 is a diagram explaining the control performed by the CPU in Figure 2, and Figure 4. 5 is a diagram showing the characteristics of the predetermined time period during which the solenoid valve is held open after switching the switching valve, FIG. 5 is a flowchart of a routine according to the division in FIG. 3, and FIG. 6 is a functional block diagram of the present invention. It is a diagram. , 14... Main transmission, 16... Sub-transmission, 24...
・High-speed gear clutch, 26...low-speed gear brake, 4
8...CPU, 56...Line pressure oil path, 66...
100...Discharge oil path, 102...Solenoid valve, 150...Instructed gear stage calculation means, 152...
・Ta calculation means, +58...Solenoid valve price control means. Patent applicant: Toyota Motor Corporation Representative: Patent attorney: Osamu Nakataira

Claims (1)

[Scope of Claims] I In a hydraulic control device for an automatic transmission, which is equipped with an auxiliary transmission connected to the output side of a main transmission having a plurality of gears and capable of manually switching between high and low gears. , a high-speed friction engagement device that achieves a high speed of the auxiliary transmission by being held in a locked state; a low-speed friction engagement device that achieves a low speed of the auxiliary transmission by being held in a locked state; A switching valve that connects the gear friction engagement device to the drain and the low gear friction engagement device to the hydraulic medium supply oil path to switch the sub-transmission from the high gear to the low gear, and the low gear friction engagement device. a solenoid valve for restricting the supply of hydraulic medium to the main transmission; and time measuring means for measuring the time elapsed since the switching valve was switched from the high gear position to the low gear position; - detecting the gear position of the main transmission; a gear position detection means for detecting a vehicle speed; a vehicle speed sensor for detecting a vehicle speed; a time calculation means for calculating a predetermined time related to a detection value of the gear position detection means and the vehicle speed sensor; and a time calculation means for determining the elapsed time measured by the time measurement means. and a solenoid valve control means for restricting the solenoid valve by an electric signal so that the supply of hydraulic medium to the friction engagement device for the low speed gear is restricted until the time calculated by is reached. , automatic transmission hydraulic control device. 2. Hydraulic control according to claim 1, wherein the solenoid valve is a valve that opens and closes an oil passage connecting an oil passage for hydraulic medium from a switching valve to a low-speed frictional engagement device to a drain. Device. 3. In a hydraulic control system for an automatic transmission equipped with an auxiliary transmission connected to the output side of a main transmission having multiple gears and capable of switching between a high gear and a low gear by manual operation, the hydraulic control device A friction engagement device for a high gear that is held in an engaged state to achieve a high gear of the auxiliary transmission; a friction engagement device for a low gear that is held in an engaged state to achieve a low gear of the auxiliary transmission; a friction engagement for a high gear A switching valve connects the device to the drain and the low speed friction engagement device to the hydraulic medium supply oil path to switch the auxiliary transmission from high speed to low speed, and connects the hydraulic medium to the low speed friction engagement device. A solenoid valve that limits the supply and a time measuring means that measures the elapsed time from the time when the switching valve is switched from the high gear position to the low gear position; 3 Gear position detection means that detects the gear position of the main gearbox. , a vehicle speed sensor that detects vehicle speed, a throttle opening sensor that detects the intake throttle opening, an oil temperature sensor that detects the temperature of the hydraulic medium, gear stage detection means, vehicle speed sensor, throttle opening sensor, and oil temperature sensor detection. A time calculation means for calculating a predetermined time related to the value, and a supply of hydraulic medium to the low speed friction engagement device until the elapsed time measured by the time measurement means reaches the time calculated by the time calculation means. A hydraulic control device for an automatic transmission, comprising: solenoid valve control means for controlling a solenoid valve by an electric signal so that the solenoid valve is restricted. 4. Hydraulic control according to claim 3, wherein the electromagnetic valve is a valve that opens and closes an oil passage connecting an oil passage for hydraulic medium from a switching valve to a low-speed friction engagement device to a drain. Device.