JPH0579857B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hydraulic control device for an automatic transmission.
In particular, the present invention relates to hydraulic control when manually switching a sub-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 gear and a low gear. In order to obtain an appropriate increase in engine rotational speed by avoiding the shift shock and excessive engine speed that occur when the auxiliary transmission changes from a high gear to a low gear while driving, the underlap period, that is, the auxiliary transmission It is necessary to control the period during which the low-speed frictional engagement device remains in the released state even after the high-speed frictional engagement device is in the released state.

Furthermore, in automatic transmissions in which the auxiliary transmission is provided on the output side of the main transmission, the inertial mass of the main transmission differs depending on the gear position of the main transmission.
Therefore, since the rate of increase in engine rotational speed during the underlap period is different, during the underlap period, not only the vehicle speed (the higher the vehicle speed is, the greater the amount of increase in engine rotational speed required at the time of switching), but also the main transmission. It is also necessary to switch depending on the gear position.

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 friction engagement device and the high-speed friction engagement device as control pressure, and these multiple control valves control the low-speed friction 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 decrease is determined according to the vehicle speed and the throttle opening degree, and furthermore, when the oil pressure of the high-speed friction engagement device drops to a predetermined level that substantially releases the high-speed friction engagement device, the low speed The oil pressure of the frictional engagement device for the lower gear is increased to a value that substantially engages the frictional engagement device for the lower gear.

However, the hydraulic control disclosed in Japanese Patent Publication No. 58-25177 is for downshifting by automatic gear shifting, and cannot be immediately applied to manual switching of the auxiliary transmission from a high gear to a low gear. This disclosure discloses control over a period in which both a stage frictional engagement device and a high-speed stage frictional engagement device are held in a slidingly engaged state. Furthermore, spool valve type control valves have a complicated configuration, and the overlap period is affected by temporal variations in the transmission of control pressure to the control valve, variations in the spring force of the control valve, and oil temperature, resulting in control accuracy. is getting lower.

Therefore, the present applicant filed another application (patent application (1) filed on May 9, 1982 by the present applicant's agent).
(No.), a solenoid valve is provided to control the supply of hydraulic medium to the low-speed frictional engagement device of the auxiliary transmission, and within a predetermined period of time after the high-speed frictional engagement device of the auxiliary transmission is connected to the drain. shows a hydraulic control device in which the electromagnetic valve blocks the supply of hydraulic medium to the frictional engagement device for low speed gears to form an underlap period. However, since engines and automatic transmissions have individual variations, in a device that controls the end of the underlap period over time, the amount of engine rotational speed that increases during a certain underlap period varies from car to car, making it difficult to properly control the underlap period. It was difficult to control.

OBJECTS OF THE INVENTION It is an object of the present invention to reduce the underlap period when the auxiliary transmission is switched from a low gear to a high gear during driving in an automatic transmission in which the auxiliary transmission is attached to the output side of the main transmission. It is an object of the present invention to provide a hydraulic control device that can appropriately and accurately control all types of automobiles regardless of variations in engines and automatic transmissions, and that has a simple configuration.

Means for Achieving the Object According to the present invention, in order to achieve this object, there is provided an auxiliary transmission connected to the output side of a main transmission having a plurality of gears and capable of switching between a high speed gear and a low gear gear by manual operation. a high speed friction engagement device that is held in an engaged state to achieve a high speed of the auxiliary transmission; and a low speed friction engagement device that is held in an engaged state to achieve a low speed of the auxiliary transmission. and a switching valve that connects the high speed friction engagement device to a drain and connects the low speed friction engagement device to a hydraulic medium supply oil path to switch the auxiliary transmission from high speed to low speed. A hydraulic control device for an automatic transmission comprising: a solenoid valve for restricting the supply of hydraulic medium to the low gear frictional engagement device; an engine rotation speed detection means for detecting engine rotation speed; A gear position detection means detects the gear position of the main transmission; a vehicle speed detection means detects the vehicle speed; and control means for controlling the electromagnetic valve by an electric signal so that the supply of hydraulic medium to the low speed friction engagement device is restricted until a predetermined value set in relation to is reached.

Function When the switching valve is switched from the high gear position to the low gear position due to manual operation by the driver, the high gear friction engagement device of the auxiliary transmission is connected to the drain, and its oil pressure begins to decrease, and finally , the high-speed stage frictional engagement device is in the released state.

On the other hand, even after the switching valve is switched, the friction engagement device for the low gear of the auxiliary transmission does not operate until the engine rotational speed reaches a predetermined value set in relation to the gear of the main transmission and the vehicle speed. The supply of hydraulic medium is restricted by a solenoid valve, which remains in the released state even after the high-speed frictional engagement device is released, resulting in an underlap period.

After the engine rotational speed reaches this predetermined value, 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 immediately supplied with hydraulic medium. is engaged, and the sub-transmission shifts to a low gear.

Effects of the Invention In the present invention, since the length of the underlap period is controlled based on the actual engine rotational speed, the length can be appropriately set without being affected by variations in the engine and automatic transmission.

The length of the underlap period depends on the gear position of the main transmission, and the engine rotational speed increases by an appropriate amount according to the gear position of the main transmission during this underlap period. It is possible to reduce the impact when switching to the engine and avoid excessive engine speed.

Since the underlap period is controlled by controlling the electromagnetic valve using an electric signal, the configuration is much simpler than that of a spool valve type hydraulic control device.

Furthermore, the underlap period of the present invention is not affected by temporal variations in the transmission of control hydraulic pressure or variations in the spring force of the control valve, so that high control accuracy can be achieved.

According to a preferred embodiment, the electromagnetic valve is a valve that opens and closes an oil passage connecting a hydraulic medium oil passage from the switching valve to the low-speed frictional engagement device to the drain.

Preferably, the predetermined value K is the product K·V of the coefficient K and the vehicle speed V, and K is a function of the gear position of the main transmission.

Furthermore, K can be set as a function of vehicle speed, intake throttle opening, and 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 frictional engagement device to shift. By relating, such deviations can be compensated for. The amount of increase in engine speed required during the underlap period varies depending on the vehicle speed V, but the coefficient K
By making V a function of the vehicle speed V, the length of the underlap period can be controlled in accordance with the required increase in engine speed. Intake throttle opening θ
As K increases, the time from the start of supply of hydraulic medium to the low-speed frictional engagement device to the actual start of engagement of the low-speed frictional engagement device, that is, the response delay, becomes shorter. This can be compensated by setting it as a function of the opening degree θ.

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

FIG. 1 shows an overall configuration diagram of an automatic transmission, and in order from upstream in the power transmission path of the engine, an engine 10, a fluid torque converter 12, a main transmission 14 having a plurality of gears, and an auxiliary transmission. 16
It is equipped with The auxiliary transmission 16 includes an input shaft 18 coupled to an output element of the main transmission 14;
A planetary gear set 2 including a sun gear coupled to
0, an output shaft 22 coupled to the carrier of the planetary gear set 20, and a high speed clutch 2 for controlling the connection between the input shaft 18 and the carrier of the planetary gear set 20;
4, and a low speed brake 26 for controlling fixation of the ring gear of the planetary gear device 20.
By engaging the high-speed gear clutch 24, the rotation of the input shaft 18 is transmitted to the output shaft 22 at a reduction ratio of 1, and by engaging the low-speed gear brake 26, the rotation of the input shaft 18 is decelerated and transmitted to the output shaft 22. Ru. 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 (output driving), etc. 32 is D selected by the driver
(drive), R (reverse), etc., and the L/H position switch 34 detects the L (low gear) and H (high gear) positions of the sub-transmission 16 selected by the driver. The oil temperature sensor 40 detects the temperature of oil as a hydraulic medium used in the hydraulic control device 42, and the engine rotation speed sensor 44 detects the rotation speed of the output shaft of the engine 10.
That is, the engine rotation speed is detected and the vehicle speed sensor 46
detects the rotational speed of the output shaft 22, which is proportional to the vehicle speed. The CPU 48 receives signals from these sensors and switches as input, 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 is connected to the oil pan 52.
It sucks in the oil inside, 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. Line pressure Pl related to opening degree θ
occurs. The L/H switching valve 60 has ports 62 and 64 connected to the line pressure oil passage 56, drains 66 and 72, and other ports 68 and 7.
0 and ports or drains 62, 64, 66, 68, 70, 7 in relation to the L and H positions.
Controls the connection between the two. L/H switching valve 60
may be of the type having a spool which is supplied with a control pressure in relation to the L and H positions and which moves in relation to this control pressure. High speed clutch 24
is held in the engaged state at the H position, and the oil passage 7
6 to port 68. The accumulator 78 is connected to the oil passage 76, and an orifice 80 and a check valve 82 are provided in parallel with each other in the middle of the oil passage 76. Check valve 82 opens to allow oil in high speed clutch 24 to flow toward port 68. The low speed brake 26 is held in an engaged state at the L position and is connected to the port 70 via an oil passage 86. The accumulator 88 is connected to the 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 is connected to the low speed brake 26
It opens when the oil flows toward port 70. The discharge oil passage 100 branches from the oil passage 86 between the port 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 is controlled by an electric signal from the CPU 48 similarly to the main speed change control circuit 54. be done.

The control performed by the CPU 48 will be explained 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 t1, L and H positions are H (high speed stage)
port 6 in the L/H switching valve 60.
8 to port 62, port 70 to drain 72,
each connected. As a result, the high speed clutch 24 is supplied with oil from the line pressure oil passage 56 and held in an engaged state, while the oil in the low speed brake 26 is discharged and the low speed brake 26 is released. maintained in the state.
Therefore, the sub-transmission 16 is in the high gear.

At time t1, the L/H position is switched from H to L (low gear) by the driver. By this switching, the control pressure of the L/H switching valve 60 is changed to
8, the spool of the L/H switching valve 60 is switched from a high speed position to a low speed position. Thus port 68 is connected to drain 66
, the ports 70 and 64 are respectively connected, and the servo oil pressure Pc begins to fall. In contrast,
The port 70 receives oil from the line pressure oil passage 56, but the solenoid valve 102 continues to open the discharge oil passage 100 even after time t1 until the engine rotational speed Ne reaches the predetermined value K·V. Pb
is held at zero, and engagement of the low speed brake 26 is prevented. Note that K is a coefficient determined by the gear position of the main transmission 14, and can also be a function of the vehicle speed V and oil temperature T ₀ as will be explained later in FIG. 4.

At time t2 when Ne reaches K·V, the solenoid valve 102 closes the discharge oil passage 100. As a result, the servo oil pressure Pb starts to rise from time t2 and reaches the predetermined oil pressure at time t3 after the elapse of the predetermined time Ta, and the low speed brake 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 released, and the engine rotational speed increases smoothly during this underlap period.

FIG. 4 shows the relationship between coefficient K and vehicle speed V. The higher the vehicle speed V is, the greater the amount of increase in engine speed required when switching the auxiliary transmission from a high gear to a low gear. Therefore, K is set as an increasing function of V, and the higher the vehicle speed lengthen the period. Also, as shown in Figure 3, the response delay Ta
However, the response delay Ta can be compensated for by setting K to a smaller value by the response delay Ta and advancing time t2. This response delay Ta becomes shorter as the intake throttle opening θ increases, so as shown in Fig. 5, K is increased as the intake throttle opening θ increases to adjust the response depending on the throttle opening θ. It is also possible to compensate for delays. Furthermore, as the oil temperature T ₀ decreases, the viscosity of the oil increases and the oil supply speed to the low-speed brake 26 decreases, so the correction coefficient K is adjusted as the oil temperature T _{0 decreases} .
As becomes smaller, set it to a smaller value and set it at time t2.
can be accelerated to compensate for the deviation in the underlap period due to the oil temperature _T0 .

FIG. 6 is a flowchart of a speed change control routine for executing the control explained in FIG. When the ignition switch is turned on (step 110), the auxiliary transmission 1
Flag F, which indicates that the operation position of gear 6 has changed from H (high gear: high speed) to L (low gear: low speed), is reset as initialization (step
112). In the main routine (step 114), the designated gear position of the main transmission 14 is calculated based on the intake throttle opening θ, the vehicle speed V, and the like. Sub-transmission 1
6 has not changed from H to L (determination in step 116 is F=0, determination in step 118 is NO), the solenoid valve for controlling the sub-transmission and the solenoid valve for controlling the main transmission are immediately driven. Control is performed according to the operating positions H and L of the sub-transmission 16 and according to the indicated gear position calculated in the main routine (steps 142 and 144). When the operating position is switched from H to L (step 118: YES), flag F is set (step 118: YES).
120). When F=1 (the judgment in step 116 is
= 1), vehicle speed V, engine speed Ne, intake throttle opening θ, and oil temperature _T0 are read (step
124, 126, 128, 130), coefficient K is the indicated gear speed Sx,
Furthermore, θ is calculated based on T ₀ (step
132). Next, compare Ne and K/V (step
134), if Ne<K・V, that is, the engine rotational speed Ne has not yet increased to K・V, turn on the underlap control solenoid valve 102 to open the drain oil passage 100 (step 136),
NeK・V, that is, the engine rotation speed Ne is K・V
If the underlap control solenoid valve 102 is turned off, the discharge oil passage 100 is closed (step 138), and F is reset (step 140).

FIG. 7 is a functional block diagram of the present invention. The indicated gear position detection means 150 detects the indicated gear position Sx of the main transmission 14. The coefficient calculation means 152 calculates the coefficient K based on the indicated gear position Sx, the throttle opening θ, and the oil temperature _T0 , and the multiplier 154 calculates the product K·V of the coefficient K and the vehicle speed V. 156 compares K·V and engine rotational speed Ne. The driving means 158 turns on the underlap control solenoid valve 102 to open the discharge oil passage 100 during a period when Ne has not yet reached K·V, and after Ne reaches K·V, it turns on the underlap control solenoid valve 102. The valve 102 is turned off, the discharge oil passage 100 is closed, and the oil at the line pressure Pl is guided to the low speed brake 26.

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 obvious to those skilled in the art that the present invention can be practiced with various modifications without departing from the spirit of the invention.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of the automatic transmission, FIG. 2 is a diagram showing the main parts of the hydraulic control device in FIG. 1, and FIG. 3 is a diagram explaining the control performed by the CPU.
Figure 4 is a graph showing the relationship between vehicle speed and coefficient;
6 is a graph showing the relationship between intake throttle opening and coefficient, FIG. 6 is a flowchart of a shift control routine according to the control shown in FIG. 3, and FIG. 7 is a functional block diagram of the present invention. 14...Main transmission, 16...Sub-transmission, 24...
...Clutch for high speed gear, 26...Brake for low speed gear, 34...L/H position sensor, 44...
Engine rotation speed sensor, 46...Vehicle speed sensor, 48
...CPU, 56...Line pressure oil path, 60...
L/H switching valve, 66...Drain, 102...
Solenoid valve, 150...indicated gear stage detection means,
152... Coefficient calculation means, 154... Multiplier, 1
56...Comparison means, 158...Driving means.

Claims (1)

[Claims] 1. A sub-transmission connected to the output side of the main transmission having a plurality of gears and capable of switching between a high speed gear and a low gear by manual operation; A high speed friction engagement device that achieves a high speed gear, a low speed friction engagement device that is held in an engaged state to achieve a low speed of the auxiliary transmission, and a high speed friction engagement device are connected to a drain. and a switching valve that connects a low-speed friction engagement device to a hydraulic medium supply oil path to switch the sub-transmission from a high-speed to a low-speed. an electromagnetic valve that limits the supply of hydraulic medium to the friction engagement device; an engine rotation speed detection means that detects the engine rotation speed; a gear position detection means that detects the gear position of the main transmission; and a gear position detection means that detects the vehicle speed. a vehicle speed detecting means for detecting a vehicle speed; A hydraulic control device for an automatic transmission, comprising: control means for controlling a solenoid valve by an electric signal so that supply of hydraulic medium to an engagement device is restricted. 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. The hydraulic control device according to claim 1, wherein the predetermined value is a product K·V of a coefficient K and a vehicle speed V, where K is a function of a gear position of a main transmission. 4. The hydraulic control device according to claim 3, wherein the coefficient K is set as a function of vehicle speed, intake throttle opening, or temperature of the hydraulic medium.