JP2882204B2 - Transmission control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for determining a power transmission path of an automatic transmission, that is, a shift stage.

[0002]

2. Description of the Related Art In an automatic transmission, a corresponding shift speed is selected by selectively hydraulically operating (engaging) various friction elements (friction clutch or friction brake), and a shift to another shift speed is performed by changing the operating friction element. It is common to do so.
In this shift, a plurality of shift valves are switched between two positions to determine a working oil path, thereby executing the selective hydraulic operation of the various friction elements.

In determining the position of the shift valve, for example, as seen in the automatic transmission described in "L4N71B Automatic Transmission Maintenance Manual" (A261C04) issued in 1982 by the present applicant, The throttle pressure corresponding to the spring and the engine throttle opening and the governor pressure corresponding to the vehicle speed act in opposition to each other in both directions, and the position of the shift valve is determined based on the balance of the forces thereby. A shift speed corresponding to a driving state of the vehicle represented by a vehicle speed can be selected.

[0004]

However, although such a hydraulic shift control device can be constructed at a low cost, the shift point,
In other words, the shift pattern is determined by the design of the shift valve,
There is only one shift pattern.

[0005] Incidentally, the shift pattern may be different between when economical driving is required, such as when driving in an urban area, and when a large amount of power is required, such as when driving on a mountainous road. Feel worse or lack power.

For this purpose, a so-called electronically controlled automatic transmission has been proposed. An example of this kind of automatic transmission is the automatic transmission described in “NISSAN Maxima New Model Manual J30 Type Car Introduction”, issued in August 1991 (FOO7671), which is being developed and used by the present applicant. .

In this automatic transmission, a shift pattern corresponding to the running conditions is selected from a plurality of shift patterns set in advance, and a suitable shift stage is determined from the engine throttle opening and the vehicle speed based on the selected shift pattern. The corresponding shift valve is switched by a constant pilot pressure so as to obtain a suitable gear position.

However, in constructing such an electronically controlled automatic transmission, the main cause of the fact that the shift valve is completely different from the hydraulically controlled automatic transmission and it is necessary to change them to another one is mainly due to the following facts. It has to be completely redesigned. Therefore, in the past, an automatic transmission capable of switching the shift pattern could be constructed only by redesigning the automatic transmission to an expensive electronic control type.

It is an object of the present invention to propose a transmission control device which can construct an automatic transmission capable of switching a transmission pattern at a low cost by using a hydraulic circuit of a hydraulic control type automatic transmission almost as it is. Aim.

[0010]

According to the present invention, there is provided a shift control device according to the present invention, wherein the 1-2 shift valve, the 2-3 shift valve, and the 3-4 shift valve are in the downshift position. By switching between the upshift position and the upshift position to selectively hydraulically operate the various friction elements, the first speed, the second speed,
Speed, third speed, and overdrive speed, wherein the 3-4 shift valve can be locked in a downshift position so that the overdrive speed is not selected by an O / D solenoid. 1-
The two-shift valve and the 2-3 shift valve and the 3-4 shift valve are configured to switch from a downshift position to an upshift position against springs at different shift signal pressures, so that a suitable shift can be performed from a driving state of the vehicle. A shift speed determining means for determining a shift speed; and a shift signal pressure generating means for supplying a pressure corresponding to the preferred shift speed determined by the shift speed to each of the shift valves as the shift signal pressure. The shift between the shift speeds is performed by the O / D solenoid through a 3-4 shift valve.

In this case, the shift signal pressure generating means includes a pressure regulating valve having a constant pressure regulating value, a solenoid capable of draining one of the input and output pressures of the pressure regulating valve, and a pressure regulating valve. Advantageously, the combination with a solenoid that locks to a pressure-disabled state produces three pressures: zero, the pressure-regulated value of the pressure-regulating valve, and the same maximum value as the input pressure.

[0012]

In the apparatus according to the first aspect, the automatic transmission is shifted as follows. That is, the gear position determining means determines a suitable gear position from the operating state of the vehicle, and the shift signal pressure generating means supplies a pressure corresponding to the preferred gear position to each shift valve as a gear signal pressure.

This pressure is applied to a 1-2 shift valve, a 2-3 shift valve, and a 3-4 shift valve to set a downshift position or an upshift position, respectively, and a 3-4 shift valve by an O / D solenoid. Is determined, the selected friction element is hydraulically actuated to bring the automatic transmission into the state in which the above-mentioned preferred gear position is selected.

According to such a shift control device, the 1-2 shift valve, the 2-3 shift valve, and the 3-4 of the hydraulically controlled automatic transmission are provided.
The shift valve itself is used by using the shift valve almost as it is, that is, by applying the pressure of the shift signal pressure generating means to these shift valves instead of the governor pressure and releasing the chamber to which the throttle pressure has been applied to the atmosphere. By changing the hydraulically controlled four-speed automatic transmission to an electronically controlled one without making any change to the configuration of the above, a four-speed automatic transmission capable of selecting a plurality of shift patterns can be constructed at low cost.

In addition, the existing O / D solenoid is used to
Since the overdrive speed is selected via the -4 shift valve, the shift signal pressure generating means only needs to generate three kinds of shift signal pressures in spite of a four-speed automatic transmission. And simplification of control can be realized.

In this case, the shift signal pressure generating means includes a pressure regulating valve having a constant pressure regulating value, a solenoid capable of draining one of the input and output pressures of the pressure regulating valve, and a pressure regulating valve for regulating the pressure regulating valve. Combination with a solenoid that locks in a pressure-impossible state
It is preferable to generate three kinds of pressures: zero, the pressure adjustment value of the pressure adjustment valve, and the same maximum value as the input pressure.

In this case, the shift signal pressure generating means can be constituted at the lowest cost, and the switching of each shift valve can be made clear, so that its malfunction can be eliminated.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 exemplifies a power transmission train of an automatic transmission to be subjected to speed change control by the device of the present invention, and also shows a fastening logic table of various friction elements in the transmission train.

This transmission train is described in the above-mentioned document "L4N71B type automatic transmission maintenance manual" (A26).
1C04), comprising an input shaft 2 to which rotational power from an engine crankshaft is transmitted via a torque converter 1 and an output shaft 3 coaxial with the input shaft.
The first planetary gear set 4 and the second planetary gear set 5 coaxially arranged on the input and output shafts and various friction elements described later.

The first planetary gear set 4 is a normal simple planetary gear set including a sun gear 4S, a ring gear 4R, a pinion 4P meshing with the sun gear 4S, and a carrier 4C rotatably supporting the pinion 4P, and a second planetary gear set 5 Also sun gear 5
S, ring gear 5R, pinion 5P, and carrier 5C
A simple planetary gear set consisting of

Next, various frictional elements that control the speed change control will be described. The carrier 4C can be appropriately connected to the input shaft 2 via the high clutch H / C, and the sun gear 4S can be appropriately fixed to the input shaft 2 by the reverse clutch R / C in addition to the sun gear 4S. I do. The carrier 4C can be further appropriately fixed by a multi-plate low reverse brake LR / B, and prevents reverse rotation (rotation in the opposite direction to the engine) via the low one-way clutch LO / C.

The ring gear 4R is integrally connected to the carrier 5C and is drivingly connected to the output shaft 3, and connects the sun gear 5S to the input shaft 2. Ring gear 5R is overrun clutch OR
/ C, and can be appropriately coupled to the carrier 4C via the forward one-way clutch FO / C and the forward clutch F / C. The forward one-way clutch FO / C connects the ring gear 5R to the carrier 4C in the reverse rotation direction (the direction opposite to the engine rotation) in a state where the forward clutch F / C is connected.

High clutch H / C, reverse clutch R
/ C, low reverse brake LR / B, overrun clutch OR / C and forward clutch F / C are respectively
The band brake B / B is operated by the supply of hydraulic pressure to perform the above-mentioned proper coupling and fixing. In particular, as shown in the logic table of FIG. 1, the second-speed servo apply chamber 2A and the third-speed servo release chamber 3R and 4B are used. It has a fast servo apply chamber 4A, which is opened in a normal state, fastened by supplying pressure only to the chamber 2A, opened when supplying pressure to the chamber 3R in addition to the chamber 2A, and opened to the chamber 4A in addition to the chambers 2A, 3R. Are also fastened when supplying pressure.

The power transmission train of FIG. 1 includes friction elements B / B, H
/ C, F / C, OR / C, LR / B, and R / C are operated in various combinations as shown in the logic table of FIG. In conjunction with the appropriate operation (engagement) of C, the rotation state of the elements constituting the planetary gear sets 4 and 5 is changed, thereby changing the rotation speed ratio of the output shaft 3 to the rotation speed of the input shaft 2 and moving forward. Fourth speed and first reverse speed can be obtained. In the table of FIG. 1, the symbol “△” also indicates operation (inflow of hydraulic pressure), and the symbol “△” indicates a friction element to be activated when engine braking is required. While the overrun clutch OR / C is being actuated as indicated by the symbol △, the forward one-way clutch FO / C juxtaposed to the overrun clutch OR / C is kept unreleased to enable engine braking, and the low reverse brake LR / B is actuated. Of course, the low one-way clutch LO / C juxtaposed therewith is kept undisengageable to allow engine braking.

Further, the forward clutch F /
The dotted circle in C indicates that this clutch remains engaged for the sake of convenience of the shift control hydraulic circuit even though it is not involved in power transmission at the fourth speed.

The shift control hydraulic circuit for the power train shown in FIG. 1 is constructed as shown in FIG. 2 in this embodiment. However, in FIG. 2, the portions according to the present invention are simplified for clarity.

Reference numeral 11 denotes a pressure regulator valve which regulates hydraulic oil from an oil pump 12 to a predetermined line pressure P _L by a well-known operation, and supplies a pressure to a circuit 13 so as to use the same as all base pressures of the automatic transmission. Output. This line pressure is supplied from the circuit 13 to the manual valve 14.

The manual valve 14 is manually operated according to the driving mode desired by the driver. When the driver wants to park (stop) the vehicle in the P (N) range, the line pressure of the circuit 13 is applied to any output circuit. Drain all output circuits without supply. When the manual valve 14 is set to the D range in order to perform automatic shifting traveling from this range, the line pressure of the circuit 13 is output to the circuit 15 and all other output circuits are drained. When the first speed engine braking is desired and the range is set to one range, the line pressure of the circuit 13 is applied to the circuit 15 and output to the circuit 16 to drain the other output circuits. Further, the manual valve 14 outputs the line pressure of the circuit 13 to the circuit 17 when the vehicle is set to the R range for the purpose of reverse traveling, and drains all other output circuits.

The circuit 15 includes a forward clutch F / C and a shift signal pressure generating means 18 which is electronically controlled as described later.
Connect to The circuit 15 further comprises a 1-2 shift valve 19, 2
Of the -3 shift valve 20 and the 3-4 shift valve 21, 1-2
It is connected to the input port 19a of the shift valve 19 and the input port 21a of the 3-4 shift valve 21 and to the input port 22a of the overrun clutch control valve 22.

1-2 shift valve 19, 2-3 shift valve 2
The 0, 3-4 shift valve 21 has the same configuration as that used in the hydraulically controlled automatic transmission.
The output ports 19c, 20c, and 21c are supported by the drain ports 19b,
d, 20d, and 21d, and the means 18
Is switched to the upshift position in accordance with the level of the shift signal pressure Ps output to the output ports 19c, 20c, 2
1c is connected to the input ports 19a, 20a and 21a.

The output port 19c of the 1-2 shift valve is connected by a circuit 24 to the second speed servo apply chamber 2A of the band brake B / B and the input port 20a of the 2-3 shift valve 20. The output port 20c of the 2-3 shift valve is a circuit 25.
3 band servo release chamber 3 for band brake B / B
R and the high clutch H / C. The output port 21c of the 3-4 shift valve is connected to the band brake B /
B is connected to the 4-speed servo apply chamber 4A.

Overrun clutch control valve 22
Is normally overrun clutch OR by spring 22b.
A circuit 27 is provided so that the output port 22c to / C can be resiliently held in a position leading to the drain port 22d and this position can be locked when pressure is present in the circuit 26. The overrun clutch control valve 22 is switched by the pressure generated or lost in the circuit 29 by the O / D solenoid 28, and when switching from the above position by the pressure in the circuit 29, the overrun clutch control valve is switched. Numeral 22 switches the output port 22c to the input port 22a for connection.

Incidentally, the pressure of the circuit 29 is controlled by the 3-4 shift valve 2.
1 and the same direction of action as the spring 21b.

The circuit 29 is connected to the circuit 15 through the orifice 30.
And to the drain port 28a of the O / D solenoid 28. The O / D solenoid 28 normally opens the drain port 28a to eliminate the pressure in the circuit 29, and closes the drain port 28a when ON to generate the same line pressure in the circuit 29 as in the circuit 15.

The shift signal pressure generating means 18 includes a pressure regulating valve 31 and
The A solenoid 32 and the B solenoid 33 are main components, and are connected and configured as shown in the figure. The pressure regulating valve 31 is supplied with the line pressure P _L from the circuit 15 to the input port 31a, and is in a position where it is normally supported by the spring 31b, and connects the output port 31c to the input port 31a. Pm. The pressure Pm is fed back to the pressure regulating valve 31 via the orifice 34 so as to oppose the spring 31b. When the pressure Pm rises and becomes equal to or more than the value corresponding to the spring force of the spring 31b, the pressure regulating valve 31 passes the output port 31c to the drain port 31d and does not further increase the pressure Pm. The output pressure Pm is adjusted to a constant value determined by the spring force of the spring 31b.

The output port 31c of the pressure regulating valve 31 is connected to the circuit 23 via an orifice 35, and the circuit 23 is connected to the drain port 32a of the A solenoid 32. A
The solenoid 32 normally opens the drain port 32a to eliminate the shift signal pressure Ps in the circuit 23, closes the drain port 32a when ON, and changes the shift signal pressure Ps in the circuit 23 to the same value as the output pressure Pm of the pressure regulating valve 31. Shall be

The pressure Pm is further passed through an orifice 36,
The pressure is supplied to the pressure regulating valve 31 so as to cooperate with the spring 31b, and this supply can be stopped by the B solenoid 33 if necessary. For this purpose, the drain port 33a of the B solenoid 33 is connected downstream of the orifice 36. The B solenoid 33 is also the same as the A solenoid 32. The drain port 33a is normally opened to release the downstream pressure of the orifice 36, and when ON, the drain port 33a is closed and the pressure Pm via the orifice 36 is applied to the pressure regulating valve 31. Shall be supplied. Therefore, when the B solenoid 33 is turned off, the pressure regulating valve output pressure Pm is set to a constant pressure value corresponding to the spring force of the spring 31b by the above-mentioned pressure regulation, and the B solenoid 33 is turned on.
At this time, the pressure regulating valve 31 becomes incapable of regulating the pressure, and the output pressure Pm reaches the same maximum value as the line pressure as the input pressure.

The shift signal pressure generating means 18 having the above configuration
Are ON and O of the A solenoid 32 and the B solenoid 33.
With the combination of the FFs, three types of shift signal pressures Ps can be generated as shown in FIG. That is, the A solenoid 32
Is turned off, the circuit 23 is connected to the drain port 32a to be in a non-pressure state irrespective of the presence or absence of the pressure regulating valve output pressure Pm, that is, regardless of the B solenoid 33, so that the shift signal pressure Ps is 0 kg · f. Becomes low level. When the A solenoid 32 is turned on and the B solenoid 33 is turned off, the pressure regulating valve 31 executes a pressure regulating action to set the output pressure Pm to a constant value corresponding to the spring force of the spring 31b.
, The shift signal pressure Ps becomes a medium level of 2.25 kg · f, for example, as shown in FIG. A solenoid 32 and both ON the B solenoid 33 Then, without give performed for pressure regulating valve 31 is regulated pressure effect, together with the same as the line pressure P _L is input pressure the output pressure Pm, it is output pressure Pm to the circuit 23 Since it is output as the shift signal pressure Ps,
Shift signal pressure Ps is the same high level as the line pressure P _L as shown in FIG.

The shift signal pressure Ps is set at each of the shift valves 19 to 21.
Is applied to these shift valves for position control, but when the shift signal pressure Ps is at a low level, all the shift valves 19 to 21 are controlled.
Is in the downshift position, and at the middle level, the 1-2 shift valve 19 switches to the upshift position, and at the high level, the 2-3 shift valve 20 and the 3-4 shift valve 21 also switch to the upshift position. As such, each spring 19b,
The spring force of 20b, 21b is determined.

The circuit 16 from the manual valve 14 is connected via a shuttle valve 38 to the low reverse brake LR / B.
And the circuit 17 is connected to the reverse clutch R / C and to the low reverse brake LR / B via the shuttle valve 37.

ON / OFF of solenoids 28, 32, 33
F is determined by a shift control controller 40 acting as a shift speed determining means, and includes a signal from a throttle opening sensor 41 for detecting an engine throttle opening T and a vehicle speed sensor 42 for detecting a vehicle speed V. And the signal M from the mode selection switch 43 operated by the driver. Mode selection switch 43
Depends on which of two preset gear shift patterns is desired, for example, an economy pattern focusing on fuel consumption shown in FIG. 7A and a power pattern shown in FIG. Alternatively, it is assumed that the driver manually operates according to whether or not they prefer the automatic mode automatically determined from the determination result of the driving state.

The operation of the above embodiment will now be described. When the driver changes the manual valve 14 from the parked / stopped range to the D range in order to desire forward automatic transmission, the line pressure is output to the circuit 15. The pressure in the circuit 15 activates the forward clutch F / C to bring the automatic transmission into a power transmittable state. On the other hand, other friction elements B /
B, H / C and OR / C are appropriately operated by the positions of the 1-2 shift valve 19, 2-3 shift valve 20, and 3-4 shift valve 21, and the control thereof is performed by the controller 40 to control the solenoids 28, 32, and 33. The operation is performed as follows through ON and OFF.

The controller 40 executes the control program shown in FIGS. 5 and 6 to operate the solenoids 28, 32, 33
N, OFF are determined.

FIG. 5 shows a main routine which is executed by, for example, a periodic interruption every 100 msec. In step 51, input information, that is, the throttle opening T, the vehicle speed V, and the selection mode M are read. In step 52, it is determined which of the shift patterns of FIGS. 7A and 7B should be selected by the subroutine of FIG.

In FIG. 6, first, at step 61, the operation position of the mode selection switch 43 is checked. If it is the automatic position, the changing speed ΔT of the throttle opening T is calculated in steps 62 and 63, and it is determined whether or not this is equal to or greater than a set value ΔTs. If ΔT ≧ ΔTs, it is considered that the operation state requires a high output, and the power pattern shown in FIG. 7B is selected in step 64. If ΔT <ΔTs, the operation does not require a high output. In step 65, the economy pattern shown in FIG. 7A is selected. Thus, step 61
If it is determined that the operation position of the mode selection switch 43 is economy or power, the control proceeds to step 65 or 64 to forcibly select a pattern requested by the driver.

In the next step 53 of FIG. 5, based on the speed change pattern selected in this manner, a speed suitable for the current driving condition is determined from the vehicle speed V and the throttle opening T. Next, at step 54, the ON / OFF of the solenoids 28, 32 and 33 for obtaining the preferred gear stage is performed.
Is determined and output to each solenoid.

When the preferred gear is the first speed, the A solenoid 32 is turned off as is apparent from FIG. In addition,
B solenoid 33 and O / D solenoid 28 are ON,
It may be OFF. When the A solenoid valve 32 is turned off, the shift signal pressure Ps is set to a low level as described above, and all the shift valves 19 to 21 are set to the down shift position. As a result, all the chambers of the band brake B / B, the high clutch H / C, and the overrun clutch OR / C are drained,
These friction elements are kept inactive. Therefore, only the forward clutch F / C is operated, and the automatic transmission is coupled with the engagement of the forward one-way clutch FO / C and the low one-way clutch LO / C, as is apparent from the logic table of FIG. , The first speed can be selected as required.

When the preferred gear is the second speed, the A solenoid 32 is turned on and the B solenoid 33 is turned off, as is apparent from FIG. The O / D solenoid 28 is O
Either N or OFF may be used. ON of the A solenoid 32,
When the B solenoid 33 is turned off, the shift signal pressure Ps is set to the middle level as described above, and the 1-2 shift valve 19 is switched to the upshift position. This allows band brake B
The line pressure of the circuit 15 is supplied to the / B second speed servo apply chamber 2A, and the band brake B / B is operated. Therefore, the automatic transmission can select the second speed as required, as is clear from the logic table of FIG. 1, in combination with the operation holding of the forward clutch F / C and the engagement of the forward one-way clutch FO / C. it can.

When the controller 40 determines that engine braking is necessary at the second speed, the O / D solenoid 28 is turned on. Thereby, the circuit 1 is added to the circuit 29.
The same pressure as the line pressure of 5 is generated, and the overrun clutch control valve 22 is stroked against the spring 22b. Therefore, the line pressure of the circuit 15 is supplied to the overrun clutch OR / C, and this clutch is operated, and as apparent from the logic table of FIG. 1, the engine brake at the second speed is enabled.

When the preferred gear is the third speed, the A solenoid 32 is turned on, the B solenoid 33 is turned on, and the O / D solenoid 28 is also turned on, as is apparent from FIG. A
As described above, when the solenoid 32 is turned on and the B solenoid 33 is turned on, the shift signal pressure Ps is set to a high level as described above.
While keeping the -2 shift valve 19 in the upshift position,
The -3 shift valve 20 and the 3-4 shift valve 21 also attempt to switch to the upshift position. On the other hand, when the O / D solenoid 28 is turned on, the same pressure as the line pressure is generated in the circuit 29, which prevents the 3-4 shift valve 21 from switching to the upshift position by cooperating with the spring 21b.
Only the 2-3 shift valve 20 is switched to the upshift position. Thereby, the band brake B / B 3
The line pressure of the circuit 24 is supplied to the high-speed servo release chamber 3R, the band brake B / B is deactivated, and the line pressure of the circuit 24 is supplied to the high clutch H / C.
This clutch is operated. Therefore, the automatic transmission can select the third speed as required, as is clear from the logic table of FIG. 1, in combination with the operation hold of the forward clutch F / C.

In the third speed, the O / D solenoid 2
The pressure generated in the circuit 29 by turning on 8 causes the overrun clutch control valve 22 to stroke against the spring 22b. Therefore, the overrun clutch OR /
The line pressure of the circuit 15 is supplied to C, and this clutch is actuated. As is clear from the logic table of FIG. 1, the engine brake is always activated at the third speed.

When the preferred speed is the fourth speed (overdrive speed), the A solenoid 32 is turned on, the B solenoid 33 is turned on, and the O / D solenoid 28 is turned off, as is apparent from FIG. ON of A solenoid 32
When the B solenoid 33 is turned ON, the shift signal pressure Ps is set to a high level as in the case of the third speed, and this is applied to the 1-2 shift valve 19, 2-3 shift valve 20 and 3-4 shift valve 21. It works in the same way as the third speed. Then, O / D
Turning off the solenoid 28 causes the pressure in the circuit 29 to disappear, which allows the 3-4 shift valve 21 to switch to the upshift position, so that the 3-4 shift valve 21 is also switched to the upshift position. This allows
The line pressure of the circuit 15 is supplied to the 4-speed servo apply chamber 4A of the band brake B / B, and the band brake B / B is operated. Therefore, the automatic transmission uses the high clutch H / C
As shown in the logic table of FIG. 1, the fourth speed can be selected as required.

By the way, as described above, the three types of shift signal pressures P
s is set, and these are assigned to the shift speeds, and the shift valve 19 is set.
According to the configuration, the strokes of all the shift valves can be controlled and the shift can be performed by applying the shift signal pressure to the shift signal pressures and using the O / D solenoid 28 to compensate for the shortage of the type of the shift signal pressure. Although the four-speed automatic transmission is used, each of the shift valves 19 to 21 has the same configuration as that of the hydraulically controlled automatic transmission, and an electronically controlled automatic transmission capable of changing the shift pattern at low cost is used. Can be built. In addition, since the existing O / D solenoid 28 is used for speed change control, the speed change signal pressure generating means 18 has three types of speed change signal pressures Ps regardless of the 4-speed automatic transmission.
The means 18 can be constructed inexpensively by combining the pressure regulating valve 31 and the solenoids 32 and 33, and the control can be easily performed only by turning on and off the solenoids 32 and 33.

When the driver sets the manual valve 14 to one range in order to desire the first speed engine braking, the circuit 15
In addition, the line pressure P _L of the circuit 13 is also output to the circuit 16. At this time, the controller 40 receives a signal from a sensor (not shown) that detects the one range, controls the shift so as to prohibit the shift to the second speed or higher, and controls the O / D solenoid 28. Turn ON. O /
When the D solenoid 28 is turned on, the same pressure as the line pressure is generated in the circuit 29, and the overrun clutch control valve 22 is stroked against the spring 22b. Therefore,
The line pressure of the circuit 15 is supplied to the overrun clutch OR / C to operate this clutch. On the other hand, the line pressure output to the circuit 16 reaches the low reverse brake LR / B via the shuttle valve 37 and activates it. As a result, the first speed is selected, and the overrun clutch OR / C and the low reverse brake LR / B are actuated. As apparent from the logic table of FIG. Make braking possible.

[0055] wishes to reverse travel, the driver when the manual valve 14 to the R range, the line pressure P _L of the circuit 13 only to the circuit 17 is output. The pressure in the circuit 17 reaches and activates the reverse clutch R / C and also reaches the low reverse brake LR / B via the shuttle valve 37 to activate it. Therefore, the automatic transmission uses the reverse clutch R / C and the low reverse brake LR.
By the operation of / B, the reverse gear can be selected as required, as apparent from the logic table of FIG.

In the shift signal pressure generating means 18,
The A solenoid 32 and the B solenoid 33 function similarly even if they are arranged at the positions shown in FIG. That is, the A solenoid 32 is for setting the shift signal pressure Ps to 0 kg · f, and the object can be achieved even with an arrangement that eliminates the input pressure supplied to the port 31a of the pressure regulating valve 31. In the example of FIG. 4, based on this concept, the A solenoid 32 is connected to a line pressure supply circuit to the pressure regulating valve input port 31a, and the orifice 38 is inserted upstream of the connection point. Further, the B solenoid 33 is used to bring the valve 31 into a state in which the valve 31 can perform a pressure regulating operation, or to lock the valve 31 in a state where the pressure cannot be regulated. As shown in FIG. 4, the pressure regulating valve output pressure Pm is fed back via the orifice 34. The purpose can be achieved even when connected to a room. Of course, it is needless to say that the A solenoid 32 and the B solenoid 33 can be arbitrarily combined with the arrangement shown in FIG. 2 and the arrangement shown in FIG.

The shift signal pressure generating means 18 of FIG. 4 can generate three kinds of shift signal pressures by the following operations by performing ON / OFF control according to the logic table shown in FIG. That is, when the A solenoid 32 is turned off, the drain port 32a is opened, the pressure regulating valve input port 31a communicates with the drain port 32a, and the downstream pressure of the orifice 38, that is, the input pressure to the pressure regulating valve 31, becomes zero. Regardless of the state of 31, that is, irrespective of the B solenoid 33, the pressure regulating valve output pressure Pm, and thus the shift signal pressure Ps, becomes a low level of 0 kg · f. When the A solenoid 32 is turned on and the B solenoid 33 is also turned on, the drain port 32a is closed when the A solenoid 32 is turned on, so that the input pressure is supplied to the pressure regulating valve 31, and when the B solenoid 33 is turned on, the drain port is turned on. 33a is closed and the pressure regulating valve output pressure Pm
As a result, the pressure regulating valve 31 performs the pressure regulating operation to make the output pressure Pm a constant value corresponding to the spring force of the spring 31b, and the shift signal pressure Ps is, for example, 2.25 kg · f. Middle level. A solenoid 32
Is turned on and the B solenoid 33 is turned off.
1 can be supplied with the input pressure when the A solenoid 32 is turned on, but the feedback of the output pressure Pm via the orifice 34 is disabled when the B solenoid 33 is turned off. Therefore, the pressure adjustment is performed by the spring force of the spring 31b. Locked in an unobtainable position. Therefore, the output pressure Pm, thus shifting the signal pressure Ps is the same height level as the input pressure line pressure P _L.

[0058]

As described above, according to the present invention, the shift control apparatus according to the present invention includes a 1-2 shift valve, a 2-3 shift valve, and a 3 shift valve.
The first shift speed, the second shift speed, the third shift speed, and the overdrive speed are selected by the -4 shift valve switching between the down shift position and the up shift position to selectively hydraulically operate various friction elements. An automatic transmission capable of locking a 3-4 shift valve to a downshift position so that the overdrive gear position is not selected by an O / D solenoid is premised on the 1-2 shift valve and the 2-3 shift valve. And a 3-4 shift valve configured to switch from a downshift position to an upshift position against a spring at different shift signal pressures, and a shift speed determining means for determining a suitable shift speed from an operating state of the vehicle. And a shift signal pressure generating means for supplying a pressure corresponding to the preferred shift speed determined by the means to the shift valves as the shift signal pressure. The shift between the drive gear position, the O / D
Since the operation is performed by the solenoid through the 3-4 shift valve, the following operation and effect can be obtained.

That is, according to the configuration of the present invention, the 1-2 shift valve, the 2-3 shift valve,
-4 The shift valve is used almost as it is, that is, the shift signal pressure generating means is applied to these shift valves instead of the governor pressure, and the chamber to which the throttle pressure is applied is released to the atmosphere. By switching the hydraulically controlled four-speed automatic transmission to an electronically controlled one without changing the configuration of the valve itself, a four-speed automatic transmission capable of selecting a plurality of shift patterns can be constructed at low cost. .

In addition, the existing O / D solenoid is
Since the overdrive speed is selected via the -4 shift valve, the shift signal pressure generating means only needs to generate three kinds of shift signal pressures in spite of a four-speed automatic transmission. And simplification of control can be realized.

At this time, the shift signal pressure generating means includes a pressure regulating valve having a constant pressure regulating value, a solenoid capable of draining one of the input and output pressures of the pressure regulating valve, and a pressure regulating valve for regulating the pressure regulating valve. A combination with a solenoid that locks in a pressure-disabled state is preferably such that three kinds of pressures are generated: zero, the pressure regulation value of the pressure regulating valve, and the same maximum value as the input pressure. in this case,
In addition to making the shift signal pressure generating means the cheapest, the switching of each shift valve is clarified, and the malfunction can be eliminated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a power transmission train of an automatic transmission to which a shift control device according to an embodiment of the present invention is applied, together with a fastening logic table of various friction elements.

FIG. 2 is a schematic circuit diagram showing only a portion according to the present invention of a transmission control hydraulic circuit of the transmission train.

FIG. 3 is a table showing output pressure characteristics of shift signal pressure generating means in the shift control hydraulic circuit and ON / OFF logic of a solenoid for obtaining each output pressure.

FIG. 4 is a table showing another example of shift signal pressure generating means together with ON / OFF logic of a solenoid.

FIG. 5 is a flowchart showing a shift control program executed by a controller in FIG. 2;

FIG. 6 is a flowchart showing a shift pattern determination program in the same program.

FIG. 7 is a diagram illustrating two types of speed change patterns: an economy pattern and a power pattern.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 torque converter 2 input shaft 3 output shaft 4 first planetary gear set 5 second planetary gear set F / C forward clutch B / B band brake H / C high clutch OR / C overrun clutch R / C reverse clutch LR / B Low reverse brake 11 Pressure regulator valve 12 Oil pump 14 Manual valve 18 Transmission signal pressure generating means 19 1-2 shift valve 20 2-3 shift valve 21 3-4 shift valve 22 Overrun clutch control valve 28 O / D solenoid 31 adjustment Pressure valve 32 A solenoid 33 B solenoid 37 Shuttle valve 40 Controller (speed-gear determining means) 41 Throttle opening sensor 42 Vehicle speed sensor 43 Mode selection switch

Claims (2)

(57) [Claims] 1. 1-2 shift valve, 2-3 shift valve, 3-shift valve
Selecting the first speed, the second speed, the third speed, and the overdrive speed by selectively switching the various friction elements to hydraulically by switching the four-shift valve between the downshift position and the upshift position; An automatic transmission in which the 3-4 shift valve can be locked in the downshift position so that the overdrive speed is not selected by the O / D solenoid. -4 shift valve is configured to switch from a downshift position to an upshift position against a spring at a different shift signal pressure, and a shift speed determining means for determining a suitable shift speed from an operating state of the vehicle is provided. A shift signal pressure generating means for supplying a pressure corresponding to the preferred shift speed determined by the means to each of the shift valves as the shift signal pressure; A shift control device for an automatic transmission, characterized in that shifting between eve shift speeds is performed by the O / D solenoid via a 3-4 shift valve. 2. A pressure regulating valve according to claim 1, wherein said shift signal pressure generating means comprises: a pressure regulating valve having a constant pressure regulating value; a solenoid capable of draining one of input / output pressures of said pressure regulating valve; A shift of an automatic transmission characterized by generating three kinds of pressures of zero, a pressure adjustment value of a pressure regulating valve, and the same maximum value as an input pressure by a combination with a solenoid that locks in an impossible state. Control device.