JPS62292539A - Automatic transmission for automobile - Google Patents

Abstract

PURPOSE:To prevent an over rotation condition by providing means for setting a comparison rotation according to a target speed change stage and forbidding shift down to the target speed change stage when the engine rotation is higher than the comparison rotation. CONSTITUTION:A controller 800 retrieves a target speed change stage then retrieves a corresponding comparison rotation which is compared with the rotation of engine E detected through a rotation sensor 804. If the engine rotation is higher than the comparison rotation, shift down to the target speed change stage is forbidden and said shift down is allowed only when the engine rotation is lower than the comparison rotation. Consequently, the engine is prevented from entering into an over rotation condition due to the torque being transmitted from a drive wheel and the speed change impact can be reduced.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention relates to an automatic transmission for an automobile, and more specifically, to an automatic transmission in which an engine rotates at a rotation speed higher than a rotation speed specific to a target gear position. The present invention relates to an automatic transmission that prohibits downshifting to a target gear position when the engine is in an overspeed state, thereby preventing an engine from rotating at a rotation speed exceeding an allowable rotation speed.

(Prior Art) As a conventional automatic transmission for automobiles, for example, Automotive Engineering Complete Book Volume 9 "Power Transmission Device" (November 2, 1980)
0, published by Sankaido Co., Ltd.), pages 238 to 251, are known. The automatic transmission for this automobile includes a torque converter and a speed change gear mechanism in which the components are connected via a clutch,
P, R, N, D4, D3 depending on shift lever operation
.

The 2nd class shift position is set.

As is well known in this type of automatic transmission, when the shift lever is operated to the UP position or to a forward automatic transmission position such as D3, the slow/ ) valve pulp opening (the amount of depression of the accelerator pedal) and the vehicle speed are changed. The clutch is automatically engaged and disconnected at a predetermined shift point to perform a gear shift. This shift point is set in a shift schedule (shift schedule) according to the performance of the engine installed in the car and the use of the car body. Appropriate gear ratios can now be obtained for automobiles.

(Problem to be solved by this invention) However,
In conventional automatic transmissions for automobiles, the shift schedule is set based on the vehicle speed and the opening of the throttle valve. When the pedal is fully depressed, kickdown is performed and the gear is shifted to a lower speed (
There was a problem in that the engine speed could exceed the permissible speed range due to a downshift.

This invention was made in view of the above-mentioned problems.
Provided is an automatic transmission for an automobile that prohibits downshifting when the engine rotational speed is equal to or higher than a rotational speed determined in accordance with a target gear position determined by a shift schedule,
The purpose is to prevent the engine from overspeeding.

(Means for Solving the Problems) This invention detects the vehicle speed and the valve opening of the throttle valve, and shifts between each element of the speed change gear mechanism according to a predetermined shift schedule determined by the vehicle speed and the valve opening of the slow/torque pulp. In an automatic transmission for an automobile that changes gears by selectively engaging and disconnecting, an engine speed detection means for detecting engine speed and a target for determining a target gear position from a shift schedule based on vehicle speed and throttle valve opening degree. gear position determining means; reference value setting means for setting a comparison rotation speed according to the target gear position determined by the target gear position determination means; and the comparison rotation speed set by the reference value setting means and the engine rotation speed. and an engine overspeed prevention means that compares the engine rotation speed detected by the cedar/intelligence means and prohibits downshifting to the target gear position when the engine rotation speed is equal to or higher than the comparison rotation speed. Features.

(Function) According to the automatic transmission for an automobile according to the present invention, a comparison rotation speed serving as a comparison standard is set according to a target gear position determined based on a shift schedule, and this comparison rotation speed and the detected engine rotation speed are set. If the detected engine speed is larger than the comparison speed, downshifting to the target gear is prohibited. Therefore, the gear ratio does not become large, and the engine does not fall into an overspeed state due to torque from the driving wheels due to the increase in the gear ratio.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 to 5 show an automatic transmission for an automobile according to an embodiment of the present invention, and FIG. 1 is a schematic diagram of a power transmission system;
FIG. 2 is a hydraulic circuit diagram, and FIGS. 3, 4, and 5 are flowcharts.

First, an overview will be explained based on FIG. ), etc., to the left and right drive wheels (W).

As is well known, the torque converter (T) consists of a pump impeller (2), a turbine launch (4) and a stator (5).
and an engine (E) input to the pump impeller (2).
) is output from the turbine launch (4) to the transmission gear mechanism (2) by the action of fluid. This torque converter (T
) is provided with a direct coupling clutch (Cd) between the pump impeller (2) and the turbine launch (4), which can directly couple the turbine launch (4) and the pump impeller (2).

This direct coupling clutch (Cd) is supplied with hydraulic pressure from a hydraulic control circuit to be described later, and directly couples the pump impeller (2) and the turbine launch (4). In addition, the details of this torque converter (T) and the speed change gear mechanism (1
4) and the details of the hydraulic control circuit are related to the patent application (Title of invention: Method for controlling a direct coupling mechanism of a hydraulic power transmission device of an automatic transmission for a vehicle) filed by the applicant on June 138, 1985. Since it is described in detail in the specification, the following explanation will be simplified.

The speed change gear mechanism (M) consists of a main shaft (3) connected to the turbine runner (4) of the torque converter (T) and a counter shirt (1B) connected to the differential gear (port f).
) are arranged in parallel, and these shafts (3).

(16) Five gear trains (G+) corresponding to the number of gears in between
.

(G)), (G3), (G4), (Gr)
are arranged side by side. The gear train (G1) for the first forward speed is
A drive gear (17) connected to the main shaft (3) via a first speed clutch (Co) and a one-way clutch (G
and a driven gear (18) connectable via o). Similarly, the second forward speed gear train (C7) includes a driving gear (19) connected to the main shaft (3) via a second speed clutch (C,), and an l shaft (
1B) and a driven gear (20) that meshes with a driving gear (19), the third forward gear train (G3)
is a drive gear (21) fixed to the main shaft (3).
) and a driven gear (22) which is connected to the counter shirt (1B) via a third speed clutch (C3) and meshes with the driving gear (21). Outside the city (G4), the driving gear (23) is connected to the main shaft (3) via the fourth speed clutch (C4) and the countershaft (16) via the switching clutch (Cs). and a driven gear (24) connected to and meshing with the teeth (23). Furthermore, the reverse gear train (Gr) is a drive gear (2) of the fourth gear train (G4).
3), and a driven gear (26) connected to the counter shirt (IEI) via the switching clutch (Cs), and both teeth* (25).
, (2!3) and an idle gear (27) meshing with the gears (2!3). Each clutch (C+), (C)), (C
3).

(C4) is connected to a hydraulic control circuit, and is connected or disconnected according to the hydraulic pressure supplied from the hydraulic control circuit. Switching clutch (C
s) is provided between the driven gear (24) and the idle gear (27) of the fourth speed gear train (G4), and the clutch (
By shifting the selector sleeve (S) of the drive float (24) and the idle gear (27) to the left forward position or right reverse position in FIG. 1B) by selectively linking to 1B). One-way clutch (Co)
transmits only the driving torque from the engine (E) to the driving wheels (privilege), and does not transmit torque in the opposite direction.

This speed change gear mechanism (M) can be operated by connecting only the first speed clutch (C) when the selector sleeve (S) is held in the forward position as shown in FIG.
17) is connected to the main shaft (3) to establish a first speed gear train (G1), and torque is transmitted from the main shaft (3) to the counter shirt (1B) via this gear train CG+). If the second speed clutch (C2) is connected while the first speed clutch (C+) is connected, its drive gear (19) is connected to the main shaft (3) and the second speed gear train ( G2) is established, and this gear train (G2)
from the main shaft (3) to the counter shaft (
Torque is transmitted to 18). At this time, the first speed clutch (C+) is also engaged, but the one-way clutch (G
Due to the movement of
2) is established, and the same holds true for third and fourth speeds. When the second speed clutch (C2) is released and the third speed clutch (C3) is connected, the driven gear (22) is connected to the countershaft (16) and the third speed tMi1 row (G
3) has been established.

Furthermore, if the third speed clutch (C3) is released and the fourth speed clutch (C4) is connected, the drive gear (23) is connected to the main shaft (3) and the fourth speed gear train (G4) is established. ke. Furthermore, move the selector sleeve (S) of the switching clutch (Cs) to the right as shown in Figure 1, and switch to the 4th gear clutch (C4).
If only the drive gear (23) is connected to the main shaft (3), the driven gear (24) is connected to the counter shirt (1G) and the reverse tIiI vehicle train (Cr
) is established, and the reverse torque is transmitted from the main shaft (3) to the countershaft (16) via this south iJi row (G'').

The torque transmitted to the countershaft (IB) is.

The power is transmitted from the output gear (28) provided at the end of the shaft (16) to the large diameter gear (Dg) of the differential gear (Df).

One end of a speedometer cable (30) is fixed to a gear (29) meshing with a gear (Ds) fixed to the gear (Dg), and a vehicle speed sensor (31) is attached to the other end of the speedometer cable (30). ) is connected to the speedometer (32) via the magnet (31a), and the speedometer (32) is connected to the gear (Ds), (28) and the cable (3
0) and displays the vehicle speed. The vehicle speed sensor (31) is composed of, for example, a reed switch (3l b) driven by the magneto-y (31a) and the bird magnet (31a), and the magnet (31a) rotates together with the speedometer cable (30). ) opens and closes the reed switch (31b), and on/off signals associated with this opening/closing are supplied to an electronic control device to be described later.

FIG. 2 shows a hydraulic control circuit.

In the figure, (P) is the aforementioned hydraulic pump that pressurizes and discharges the hydraulic oil in the reservoir (R), and the hydraulic pump (
P) discharges pressure oil to the regulator valve (Vr), manual valve (Vm), and governor valve (Vg). The regulator valve (Vr) has a spool (132a) connected to a boat (80b).
) in response to the pressure of the pressure oil supplied from the pump (P) and the elastic force of the spring (82b), the boat (Boa)
, A part of the pressure oil supplied from the pump (P) to (Bob) is transferred from (80c) to the torque converter (T),
It is supplied to the on-off valve (230) and the timing valve (210), and also from the reservoir (R
) to adjust the hydraulic pressure supplied to the manual valve (vl) etc. to line pressure (PR). Note that (253) is a relief valve provided at (80d) of the regulator valve (Vr).

As is well known, in the torque converter (T), supplied pressure oil flows from the pump impeller (2) through the stator (5) to the turbine launch (4), and torque is transmitted using this pressure oil as a medium. do. The oil pressure of this torque converter (T) is controlled by a pressure holding valve (250) and an oil cooler (260).
) to the reservoir (R). Pressure holding valve (250)
The governor pressure (described later) generated by the governor valve (Vg) is guided by the boat (250b), and the spool (251) responds to the governor pressure and the elastic force of the spring (252), causing the boat (250a) to (25
0c) to the reservoir (R). This pressure holding valve (2
50) is the torque converter (T) at the high vehicle speed position.
functions to reduce the internal pressure of the

The spool (71) of the manual valve (V-shoe) responds to manual operation of the shift lever and is in the parking position! 1 (P), reverse position (R), neutral position (N), automatic shift position of 4 forward speeds and (0
4) Automatic shift position of 3 forward speeds excluding 4th speed at (D: +
) and 2nd gear fixed position (2), each clutch (CHI), (C2), (C3
), (C4) and each boat (70a) to (7on) connected to the servo piston (90) etc. 0 For example, when the shift lever is operated to the N position, the manual valve (Vm) The spool (71) is in the position shown to close the boat (?Ob) and all other boats (70a).

(70c) - (?On) is communicated with the drain port (EX). Therefore, as is clear from the figure, each clutch (C+), (C2), (
No pressure oil is introduced into C3) and (C4),
These clutches (C+) to (C4) are placed in a disconnected state. For example, when the shift lever is operated to the (04) position, the spool (71) moves to the left by one position in the figure, and the servo piston (90), the first throttle valve (Vt), and the pressure reducing valve (270) move to the left. The boat (170c) connected to the pump (P) and the boat (70h) connected to the flow control valve (400) and the non-creep valve (Vc) are connected to the boat (?Ob) connected to the pump (P), and the second speed (70g) connected to the clutch (C?) and the boat (70f) connected to the second shift valve (vl),
Furthermore, the fourth speed clutch (C4) and timing valve (
210) to J! I! The involved boat (70k) and the boat (7 (im)) connected to the second shift valve (vl), (7
0n) and Bo) (?Oi) are separated from each other and communicated with each other.

Note that a description of the case where the shift lever is operated to another position will be omitted.

The servo piston (30) has each boat (90a)
.

(90b), (90c) Nff Niall valve (Vl
ll) (7) Bo) (70i).

Pressure oil is introduced from (70c) and (70a), and the spool (91a) responds to the pressure in the chamber communicating with the boat (90b), the pressure in the chamber communicating with the boat (90c), and the elastic force of the spring (91b). Displace accordingly. The right end of the spool (91a) in the figure of this servo piston (80) is the selector sleeve (S) of the aforementioned switching clutch (C!l).
When line pressure (PJI) is introduced to the boat (90b) via the manual valve (Vm), the selector sleeve (S) is held in the position shown in Fig. 1 and the fourth speed gear train (G
4) Connect the driven vehicle (20) to the countershaft (16).

The governor valve (Vg) connects the pump (P) to the boat (80a).
of the discharged oil is guided, and this discharged oil is subjected to a pressure proportional to the vehicle speed (
pressure (Pg)) and output from the boat (80b) to the second shift valve (v2), the modulator valve (220), and the above-mentioned pressure holding valve (250).

The first throttle valve (Vt) has a first spool (10) engaged with a cam (104) that interlocks with the throttle valve.
1) The second spool (102) coupled to the first spool (101) via the spring (103) is connected to the cam (
104) and is displaced by the manual valve (Vm).
The pressure oil supplied to the boat (1.0 Oa) is adjusted to create a pressure (throttle pressure (Pt)) proportional to the valve opening of the throttle valve, that is, the amount of depression of the accelerator pedal.
occurs on boats (100b) and (100c).

The throttle pressure (pt) generated by this first throttle valve (Vt) is
7th cumulator (180), 47th cumulator (
190), modulator valve (220), on-off valve (230), flow control valve (400), first control valve (lfiO), second control valve (181), third control valve (182) and bow ) (300e). In addition, the first spool (101) is displaced and the second shift valve (v2) of this ml throttle valve (Vt)
The boat (100d) and the drain boat (Ex
) to reduce the shift shock during kickdown.

The pressure reducing valve (270) is a well-known one. (270a)
The line pressure (PJI) introduced from the manual valve (V snow)
) is depressurized and output from (2? Ob) to the first shift valve (V +).

The flow rate control valve (400) is configured so that the boat (400a) is the first shift valve (Vl), (400b), (40
0c) Ka? = 7 Jl/valve (Vw) 2, mata, boat (400d) is connected to spool (401) and throttle pressure (pt) introduced from throttle valve (Vt) and spring (40
The flow rate supplied to the first shift valve (vl) is adjusted in response to the elastic force of step 2). This flow control valve (aOO) is
The amount of oil supplied to the first shift valve (VD) is controlled by the throttle pressure (
pt) to prevent a plurality of clutches from being connected to each other, thereby reducing shift shock.

The first shift valve (vl) includes a boat (120a) connected to a pressure reducing valve (270), and a boat (120a) that is constantly in communication with this boat (120a) and connected to a first solenoid valve (140).
+2b), is opened to the drain (EX) and the second
a boat (120c) connected to a control valve (161) of
Boat (120d) connected to second shift valve (v2)
), (120e) baud opened to the drain (EX) and communicated to the second throttle valve (110))
(12or) and a bow) (120g) connected to a flow control valve (aOO).

Boat (1) controlled by first solenoid valve (140)
20a), (120b) hydraulic pressure and spring (121
b) (7) The spool (121a) responds to the elastic force and the boat (120G), (+20d), (120e),
(120f) and (120g) are selectively communicated.

That is, in the illustrated position where the spool (121a) is at the right end in the figure, the boat (120c), (120d)
In the position where the space between the boat (120e) and the boat (120g) are in communication, and the spool is displaced to the left end in the figure,
boat) (120d) (120g) and boat (1
20e) and (120f) are connected. The first solenoid valve (140) has a solenoid (140a) connected to an electronic control device (described later), and when the solenoid (140a) is energized, the valve opens and the first shift valve (Vl) (7) boat (
120b) to the drain (Ex).

The second throttle valve (110) has a spool (111) engaged with a cam (113) that communicates with the throttle valve.
is driven by the cam (113) and the spring (112)
(110a) and a drain boat (EX) displaced against the elastic force of and connected to the first shift valve (vl)
Continuously change the area of the flow path between the This second throttle valve (110) changes the pressure from the first shift valve (V-reverse boat (120f) to Am) to shift from the fourth gear to the third gear.
Reduces shift shock when downshifting to higher speeds.

The second shift valve (v2) is connected to the governor valve (Vg) (130a), the first throttle valve (Vt
) of the first shift valve (vl) (130b), the boat (120d) connected to the first shift valve (vl)
130C), a boat (13Qd) connected to the second solenoid valve (150), a boat (13Qd) of the first shift valve (vl)
Boat (130e) connected to manual valve (Vm) (700)
f), Manual valve (Vm) boat (70m), (
Boat (130g) connected to boat (70n), boat (+3) connected to boat (70a) with manual valve (7 layers)
0i), a boat (130k) opened via the first control valve (180) and a boat (130h) connected to the third gear clutch (C3),
) responds to the hydraulic pressure in the room at the right end in the figure that communicates with the boats (130a) and (130d) and the elastic force of the spring (132). This second shift valve (vl) operates when the spool (131) is in the illustrated position at the right end in the figure.
boat) (130b) and boat (130h), boat (
130c) and a boat (130f).

and the boat (130g) and the drain boat (EX), and when the spool (+31) is at the leftmost position in the figure, the boat (130c) and the boat (130
h).

This second shift valve (v2) communicates between the boat (130f"l and the boat (130k) and the boat (130e) and the boat (130g).
130d) (7) The hydraulic pressure, that is, the pressure movement of the spool (131) is controlled by the second ift solenoid valve core valve 50), and when the second solenoid valve (150) is opened, the illustrated position is controlled, and the second WLfi1 When the valve (15θ) is closed, it takes the leftmost position in the figure. Note that (131) is a click motion mechanism that selectively limits the position of the spool (131).

The non-creep valve (Vc) is connected to a manual valve (7 layers) (300a), (300b), and a boat (300c) connected to a manual valve (Vm) via a third solenoid valve (310). ), the boat (300d) connected to the first gear clutch (C1) and the boat (300d) connected in parallel to the check valve and the third control valve (182)
e), and the spool (301) is connected to the boat (300a).
, (300e) and the spring (302)
It responds to the elastic force of The spring (302) is secured by a lock nut (304).
3) and the spool (301), and the bolt (
Spool (301) by changing the screw length of (303)
The elastic force applied to is adjusted. This non-creep valve (
In the illustrated position where the spool (301) is at the lower end in the figure, the VC) closes the bow (300c) to communicate between the boat (300b) and the boat (300d), and the spool (301) ) is located at the upper end of the figure, and the boat (3ooc) is connected to the boat (EX). The third solenoid valve (31O) is a solenoid (31
0a) is connected to the electronic control unit, and the solenoid (310
The valve opens when the current is applied in a).

The third control valve (162) is a non-creep valve (vc) when the slow 2 torr pressure (pt) is small (300
The throttle pressure (Pt) is guided to e), but the throttle pressure (Pt) is
When t) is large, line pressure (P2) is introduced.

The timing valve (210) is connected to the second gear clutch (C9) (210al fourth gear clutch (C4)).
) (210b), a boat (210c) connected to regulator r (Vr),
) (210d) connected to the inlet boat of the lux converter (T) and two boats (210e), (210F) connected to the modulator valve (220), with the spool (211) connected to the spring (212 ) and the pressure of the boats (210a) and (210b). In this timing valve (210), when the second speed clutch (C2) or the fourth speed clutch (C4) is in the engaged state, the spool (211) moves to the left in the figure and takes the position at the left end in the figure. When the speed clutch (C7) or the fourth speed clutch (C4) is in the released state, the spool (211) moves to the right in the figure and assumes the position shown at the right end in the figure. This timing valve (210) communicates between the boats (210c) and (210e) at both the left end in the figure and the right end in the figure.
During the transition, the boats (210c) and (210e) are cut off, and the boat (210f) is connected to the drain boat (E).
isolate from X).

The modulator valve (220) is a first throttle valve (V
t) into which the throttle pressure (pt) is introduced from the boat (2
20a), governor pressure (Pg) from governor knob r (Vg)
(220b), timing valve (220b),
10) two boats (220c), (22
0d), baud) communicated to the on-off valve (230)
(22Qe) and a boat (220f) connected to the direct coupling clutch (Cd), and the spool (221) is turned on and off in response to the internal pressure of the direct coupling clutch (Cd), throttle pressure (Pt) and governor pressure (Pg). A pressure proportional to the vehicle speed and the throttle valve opening is output to the valve (23G).

The on-off valve (23G) is the first throttle valve (Vt)
A boat (230a) that is connected to the inlet port of the torque converter (T) (230a) to introduce throttle pressure (Pt), a boat (230b) that is connected to the regulator valve (V'), and a boat (230c) that is connected to the inlet boat of the torque converter (T). , direct clutch (
Boat (230d) connected to the piston of Cd) and Boat (230d) connected to the modulator valve (220).
30e).

The spool (231) responds to the throttle pressure (Pt) and the elastic force of the spring (232). This on-off valve (230) communicates the boat (230a) with the drain boat (EX) and the boat (230b) during idling operation of the engine with a small throttle pressure (Pt).
).

(210c) to release the direct coupling clutch (Cd) and increase the amount of oil supplied to the torque converter (T).

In the direct clutch (Cd), the piston pressure chamber is the fourth TL.
This fourth solenoid valve (240) is connected to the solenoid valve (240).
0). When the solenoid (240a) is connected to the electronic control device and the solenoid (24oa) is energized and excited, the fourth solenoid valve (240) operates as a direct clutch (
Drain boat (241)
Ex) to shift the direct coupling clutch (C'd) to the released state side.

The second speed clutch (C2) is the 27th curator (170)
The third speed clutch (C3) is connected in parallel with the third accumulator (180) and the first control valve (180).
The fourth speed clutch (C4) is connected in parallel with the fourth accumulator (190) and the second control valve (t
et) are connected in parallel with each 7 as well-known.
Cumulator (1?Q) , (180) , (190)
reduces the shift shock, and the first control valve (180
) and the second control valve (181) determine the characteristics when the clutch is released. In addition, in FIG. 2, (OH) represents an aperture.

(800) is an electronic control device equipped with a one-chip microcomputer, etc., and this electronic control trace! (800) is ROM
The above-mentioned vehicle speed sensor (31), which stores the shift schedule and comparative rotational speed, etc., detects the vehicle speed, the accelerator sensor (803), which detects the valve opening of the throttle valve, and the rotational speed, which detects the rotational speed of the engine (E). Several sensors (
Along with various sensors such as engine rotation speed detection means) (804), each of the above-mentioned magnetic valve core valves 40), (150), (
240), (310), etc. are connected, and energization control of the solenoid valve is performed based on the output signal of each sensor. In addition, this electronic side g# equipment! (800) includes a target gear determining means for determining a target gear from a shift schedule, a reference value setting means for determining a comparison rotation speed according to the target gear, and a reference value setting means for determining a comparison rotation speed according to the detected engine rotation speed and the comparison rotation speed. This corresponds to engine overspeed prevention means that prohibits downshifting.

In such a hydraulic control circuit, as shown in the table below, the solenoids (140a) and (150c) of the first and second solenoid valves (140) and (150) are connected to the electronic control trace 21 (80).
0) 4. : Therefore, the valves are selectively energized and each clutch (C+), (C2), ((a), (0
4) to establish any one of the first to fourth speeds of the transmission gear mechanism (M) according to the vehicle speed and the opening degree of the throttle valve.

Next, the operation of this embodiment will be explained.

The automatic transmission of this automobile is shown in Figures 3, 4 and 5.
The series of processes shown in the flowchart in the figure is performed by the electronic control unit (
8oo) is repeatedly executed and controlled at a predetermined period.

First, when the ignition switch is turned on, in step (h), the CPU of the electronic control unit (800) is initialized, and in the zeroth step (Pt), the engine (E) is operated with its own blade. In other words, it is determined whether the rotation speed (Ne) of the engine (E) exceeds a predetermined rotation speed (Neo) (for example, 300 [r, P, m, ]) at which it can be determined that the engine (E) is in an operating state. However, if the rotation speed (Me) of the engine (E) exceeds the predetermined rotation speed (Neo) and the engine (E) is in the operating state, the process proceeds to step (R3), and the rotation speed (Me) of the engine (E) ) is below the predetermined rotational speed (Neo), the process proceeds to step (R4).

In step (R3), input data is read from various sensors such as the vehicle speed sensor (31), and in the subsequent step (R5)
Input data processing such as storage of input data is performed in the next step (R6), and in the next step (R6), the torque converter (
Calculate the speed ratio (e) of T). This speed ratio (e) is
The rotational speed of the turbine runner (4) and the pump impeller (2)
) and the rotation speed. The following steps (
In step R7), non-creep control is performed based on vehicle speed data, etc. In this step (R7), the third solenoid valve (310
) Determine the radio wave to energize the solenoid (3108),
Through the output processing in step (Pat) to be described later, the third solenoid valve (182) is energized and the first gear clutch (2) is activated.
Adjust the oil pressure supplied to C1).

In the next step (R8), the processes shown in the flowcharts of FIGS. 4 and 5, which will be described later, are executed to perform gear change control, and then, in step (R9), the gear ratio calculated in the above-mentioned step (R6) is The capacity of the direct coupling clutch (Cd) is controlled based on (e) etc.

On the other hand, in the step (R4) described above, processing is performed to maintain the gear stage of the automatic transmission at the third forward speed.
I+1) to release the clutch (Cd).

After this, in step (Pn), output processing such as energizing the solenoid valve is performed based on the processing results of each step described above, and after the processing of step 2 (Pn) is completed, step (R2 ) is executed repeatedly.

The speed change control in step (R8) is performed by executing the process shown in the flowchart of FIG. first,
After performing a map search in step (Ql), step (
In Q2), the shift schedule retrieved from the map is deciphered.In the next step (Q3), the direct coupling clutch (Cd) is controlled based on the result of decoding the shift schedule, and in the following step (Q4), the shift order is controlled. .

In the shift order control of step (Q4), a series of processes shown in the flowchart of FIG. 5 are performed. First, in step (R1), it is determined whether the current gear position (SO) is smaller (lower speed) than the searched gear position (S), and the current gear position (SO) is determined to be lower than the searched gear position (S). ), proceed to step (R7); if the current gear (SO) is the same as or larger than the searched gear (S), proceed to step (R11); in step (R2), the down timer (YT) is reset. and a predetermined time (Data O
), and in the next step (R3) it is determined whether the kickdown state is present or not, that is, the valve opening degree (TH) of the throttle valve.
It is determined whether or not it is fully open (100 [Xl). In this step (R3), the valve opening degree (TH) is fully open (10 (D$)
), the process proceeds to step (R4),
Furthermore, if it is determined that the valve opening (CTH) is fully open (100 ($)), the process proceeds to step (R7). In step (R4), the up timer (ZT) has completed timing (TIP). The up timer (
If the timing of the up timer (ZT) has not been completed, the process proceeds to step (R5) and outputs the current gear (SO) as the gear (S) to be commanded. If the timing of the up timer (ZT) has been completed, the stage As the gear (S) to proceed to step 2 (R6) and command, select a gear (SO+1) that is one gear higher than the current gear (SO).
Output. Then, as mentioned above, based on the instructions of these steps (Rs) and (Re), step (P
In the output process of o), the solenoid valves (140) and (t5o) are energized. Therefore, the gear stage will not be shifted up beyond one gear, and will not be shifted up unless a predetermined period of time has elapsed, reducing the temporal speed change rate of the gear ratio and causing shift shock. Reduced. After this,
In step (R7), the up timer (ZT) is reset to set a predetermined time (Data O).

On the other hand, in step 2 (Re) mentioned above, step E (
Similarly to R7), the up timer (ZT) is reset, and in the following step (R9), it is determined whether the gear position (S) searched on the map is the same as the current gear position (SO), and the searched gear position (SO) is determined. If the gear position (S) and the current gear position (SO) are the same, the above-mentioned step (R5) is executed; if the searched gear position (S) and the current gear position (SO) are different, step (R5) is executed. In step (Rho), it is determined whether or not the down timer (YT) has completed timing (UP), and if the down timer (YT) has completed timing, the process advances to step (R++). Proceed to the engine (E) rotational speed (
Me) is smaller than a predetermined rotational speed (New), and if the down timer (YT) has not completed counting, the current gear (SO) is maintained in step (Rs) described above. Therefore, unless a predetermined period of time has elapsed, the current gear position (SO) is maintained and no downshift is performed, and the temporal change rate of the gear ratio is reduced, thereby alleviating the shift shock.

In step (Rh), 1 rotation speed sensor (804)
The comparison rotation speed (Me) determined according to the rotation speed (Me) of the engine (E) detected by
(Hem). This comparative rotation speed (Me■) is
The forward speeds are set separately for 4th forward speed, 3rd speed, 2nd speed, and 1st speed, and are stored in a storage device such as a ROM. Although not shown in this flowchart, when the target gear (S) is searched on the map, the comparison rotation speed (Me) is also searched in accordance with the target gear (S). Note that, as in this embodiment, the gear position to be downshifted is the current gear position (SO
), it is possible to determine the comparison rotation speed (Me layer) for the current gear (S). If it is determined that the engine rotation speed (Me) detected in this step (R++) is smaller than the comparison rotation speed (Hem), the process proceeds to step (R12) where the gear position is one step lower than the current gear position (SO). (so-1) and also this step (R
n), the engine speed (Me) is the comparative speed (Me layer)
If it is determined that this is the case, the current gear position (SO) is maintained at the aforementioned step (R5). In other words, the engine rotation a (Me) is the comparative rotation speed (Ne+s) specific to the gear position.
A downshift is allowed only when the engine speed (Ne) is smaller than the comparison speed a (New
') or above, downshifting is prohibited. Therefore, the engine (E) is prevented from over-speeding due to the torque transmitted from the drive wheels, and since the engine (E) is sequentially downshifted according to the magnitude of the gear ratio, the shift shock is also reduced.

In the following step (Rho), the above-mentioned step (R3
), it is determined whether the valve opening degree (TH) of the throttle valve is fully open (loo[Xl) or not, and the valve opening degree (TH
) is fully open, proceed to step (R+t), and if the valve opening (T) I) is not fully open, proceed to step (Rho). In step (RI4), the down timer (Y
T) and set the down timer (YT) to a relatively short predetermined time (Data 1);
In step (Rls), the down timer (YT) is set to a predetermined time (D
ata 2). Therefore, when the gear is downshifted by more than one gear during kickdown, etc.,
The next downshift can be carried out promptly, and the deterioration of the interlocking performance (acceleration performance) of the automobile can be prevented.

As described above, in the automatic transmission for a vehicle according to this embodiment, downshifting is prohibited when the engine speed exceeds the speed set according to the gear position, so that the engine (E ) will no longer be in an over-speed state.

In addition, in the above-mentioned embodiment, the present invention is applied to a parallel gear type automatic transmission with four forward speeds.
It goes without saying that the present invention is also applicable to those using speed or planetary gear mechanisms.

(Effects of the Invention) As explained above, according to the automatic 1V automatic transmission according to the present invention, when the engine rotation speed is higher than the rotation speed specific to the gear determined according to the gear Since downshifting is prohibited during gear shifts, the engine will not overspeed when changing gears.

[Brief explanation of the drawing]

1 to 5 show an automatic transmission for an automobile according to an embodiment of the present invention, in which FIG. 1 is a frame diagram of a power transmission system, FIG. 2 is a hydraulic circuit diagram, and FIGS. 3 and 4. and FIG. 5 are flowcharts. E... Engine Cd... Direct clutch T... Torque converter M... Speed change gear mechanism C1, C2, C3, C4, C5... Clutch 31...
・Vehicle speed sensor 800...Electronic control device (target gear stage determination means, reference value setting means, engine overspeed prevention means) 803...Accelerator sensor 804...Revolution speed sensor (engine rotation speed detection means) Patent application Person Honda Motor Co., Ltd. agent Patent attorney 2 1) Production department Patent attorney Kuni Ohashi Production volume Patent attorney Koyama Nankai Patent attorney No 1)
1 Figure 1 J/ , j7b Figure 4

Claims (1)

[Claims] Detecting the vehicle speed and the valve opening of the throttle valve,
An engine rotation speed detection means for detecting engine rotation speed in an automatic transmission for an automobile that changes speed by selectively connecting and disconnecting each element of a transmission gear mechanism according to a predetermined shift schedule determined by vehicle speed and throttle valve opening degree. and a target gear position determining means for determining a target gear position from a shift schedule based on the vehicle speed and the valve opening of the throttle valve, and setting a comparison rotation speed according to the target gear position determined by the target gear position determining means. Reference value setting means;
Comparing the comparison rotation speed set by the reference value setting means and the engine rotation speed detected by the engine rotation speed detection means, and shifting to the target gear when the engine rotation speed is equal to or higher than the comparison rotation speed. An automatic transmission for an automobile, comprising: an engine overspeed prevention means for prohibiting engine down.